164907961
Impact of maternal malnutrition on gut barrier defence: implications for pregnancy health and fetal development
Small intestinal Paneth cells, enteric glial cells (EGC), and goblet cells maintain gut mucosal integrity, homeostasis, and influence host physiology locally and through the gut-brain axis. Little is known about their roles during pregnancy, or how maternal malnutrition impacts these cells and their development. Pregnant mice were fed a control diet (CON), undernourished by 30% vs. control (UN), or fed a high-fat diet (HF). At day 18.5 (term=19), gut integrity and function were assessed by immunohistochemistry and qPCR. UN mothers displayed reduced mRNA expression of Paneth cell antimicrobial peptides (AMP; Lyz2, Reg3g) and an accumulation of villi goblet cells, while HF had reduced Reg3g and mucin (Muc2) mRNA and increased lysozyme protein. UN fetuses had increased mRNA expression of gut transcription factor Sox9, associated with reduced expression of maturation markers (Cdx2, Muc2), and increased expression of tight junctions (TJ; Cldn-7). HF fetuses had increased mRNA expression of EGC markers (S100b, Bfabp, Plp1), AMP (Lyz1, Defa1, Reg3g), and TJ (Cldn-3, Cldn-7), and reduced expression of an AMP-activator (Tlr4). Maternal malnutrition altered expression of genes that maintain maternal gut homeostasis, and altered fetal gut permeability, function, and development. This may have long-term implications for host-microbe interactions, immunity, and offspring gut-brain axis function.
5759713
Paneth cells directly sense gut commensals and maintain homeostasis at the intestinal host-microbial interface
The intestinal epithelium is in direct contact with a vast microbiota, yet little is known about how epithelial cells defend the host against the heavy bacterial load. To address this question we studied Paneth cells, a key small intestinal epithelial lineage. We found that Paneth cells directly sense enteric bacteria through cell-autonomous MyD88-dependent toll-like receptor (TLR) activation, triggering expression of multiple antimicrobial factors. Paneth cells were essential for controlling intestinal barrier penetration by commensal and pathogenic bacteria. Furthermore, Paneth cell-intrinsic MyD88 signaling limited bacterial penetration of host tissues, revealing a role for epithelial MyD88 in maintaining intestinal homeostasis. Our findings establish that gut epithelia actively sense enteric bacteria and play an essential role in maintaining host-microbial homeostasis at the mucosal interface.
16193738
Gut microbiome-host interactions in health and disease
The gut microbiome is the term given to describe the vast collection of symbiotic microorganisms in the human gastrointestinal system and their collective interacting genomes. Recent studies have suggested that the gut microbiome performs numerous important biochemical functions for the host, and disorders of the microbiome are associated with many and diverse human disease processes. Systems biology approaches based on next generation 'omics' technologies are now able to describe the gut microbiome at a detailed genetic and functional (transcriptomic, proteomic and metabolic) level, providing new insights into the importance of the gut microbiome in human health, and they are able to map microbiome variability between species, individuals and populations. This has established the importance of the gut microbiome in the disease pathogenesis for numerous systemic disease states, such as obesity and cardiovascular disease, and in intestinal conditions, such as inflammatory bowel disease. Thus, understanding microbiome activity is essential to the development of future personalized strategies of healthcare, as well as potentially providing new targets for drug development. Here, we review recent metagenomic and metabonomic approaches that have enabled advances in understanding gut microbiome activity in relation to human health, and gut microbial modulation for the treatment of disease. We also describe possible avenues of research in this rapidly growing field with respect to future personalized healthcare strategies.
9735482
Bacteria as vitamin suppliers to their host: a gut microbiota perspective.
Food-related lactic acid bacteria (LAB) as well as human gut commensals such as bifidobacteria can de novo synthesize and supply vitamins. This is important since humans lack the biosynthetic capacity for most vitamins and these must thus be provided exogenously. Although vitamins are present in a variety of foods, deficiencies still occur, mainly due to malnutrition as a result of insufficient food intake and because of poor eating habits. Fermented milks with high levels of B-group vitamins (such as folate and riboflavin) can be produced by LAB-promoted and possibly bifidobacteria-promoted biosynthesis. Moreover, certain strains of LAB produce the complex vitamin cobalamin (or vitamin B12). In this review, fermented foods with elevated levels of B-group vitamins produced by LAB used as starter cultures will be covered. In addition, genetic abilities for vitamin biosynthesis by selected human gut commensals will be discussed.
6844710
Mechanisms controlling pathogen colonization of the gut.
The intestinal microbiota can protect efficiently against colonization by many enteric pathogens ('colonization resistance', CR). This phenomenon has been known for decades, but the mechanistic basis of CR is incompletely defined. At least three mechanisms seem to contribute, that is direct inhibition of pathogen growth by microbiota-derived substances, nutrient depletion by microbiota growth and microbiota-induced stimulation of innate and adaptive immune responses. In spite of CR, intestinal infections are well known to occur. In these cases, the multi-faceted interactions between the microbiota, the host and the pathogen are shifted in favor of the pathogen. We are discussing recent progress in deciphering the underlying molecular mechanisms in health and disease.
1892064
Bowels control brain: gut hormones and obesity
Food intake and energy expenditure are tightly regulated by the brain, in a homeostatic process that integrates diverse hormonal, neuronal and metabolic signals. The gastrointestinal tract is an important source of such signals, which include several hormones released by specialized enteroendocrine cells. These hormones exert powerful effects on appetite and energy expenditure. This Review addresses the physiological roles of peptide YY, pancreatic polypeptide, islet amyloid polypeptide, glucagon-like peptide 1, glucagon, oxyntomodulin, cholecystokinin and ghrelin and discusses their potential as targets for the development of novel treatments for obesity.
1791045
The inflammatory reflex
Inflammation is a local, protective response to microbial invasion or injury. It must be fine-tuned and regulated precisely, because deficiencies or excesses of the inflammatory response cause morbidity and shorten lifespan. The discovery that cholinergic neurons inhibit acute inflammation has qualitatively expanded our understanding of how the nervous system modulates immune responses. The nervous system reflexively regulates the inflammatory response in real time, just as it controls heart rate and other vital functions. The opportunity now exists to apply this insight to the treatment of inflammation through selective and reversible 'hard-wired' neural systems.“The mind has great influence over the body, and maladies often have their origin there.” Molière (1622–1673).
205538522
Childhood malnutrition and the intestinal microbiome
Malnutrition contributes to almost half of all deaths in children under the age of 5 y, particularly those who live in resource-constrained areas. Those who survive frequently suffer from long-term sequelae including growth failure and neurodevelopmental impairment. Malnutrition is part of a vicious cycle of impaired immunity, recurrent infections, and worsening malnutrition. Recently, alterations in the gut microbiome have also been strongly implicated in childhood malnutrition. It has been suggested that malnutrition may delay the normal development of the gut microbiota in early childhood or force it toward an altered composition that lacks the required functions for healthy growth and/or increases the risk for intestinal inflammation. This review addresses our current understanding of the beneficial contributions of gut microbiota to human nutrition (and conversely the potential role of changes in that community to malnutrition), the process of acquiring an intestinal microbiome, potential influences of malnutrition on the developing microbiota, and the evidence directly linking alterations in the intestinal microbiome to childhood malnutrition. We review recent studies on the association between alterations in the intestinal microbiome and early childhood malnutrition and discuss them in the context of implications for intervention or prevention of the devastation caused by malnutrition.
13674953
Marked differences in tight junction composition and macromolecular permeability among different intestinal cell types
BackgroundMammalian small intestinal tight junctions (TJ) link epithelial cells to one another and function as a permselective barrier, strictly modulating the passage of ions and macromolecules through the pore and leak pathways, respectively, thereby preventing the absorption of harmful compounds and microbes while allowing regulated transport of nutrients and electrolytes. Small intestinal epithelial permeability is ascribed primarily to the properties of TJs between adjoining enterocytes (ENTs), because there is almost no information on TJ composition and the paracellular permeability of nonenterocyte cell types that constitute a small but significant fraction of the intestinal epithelia.ResultsHere we directed murine intestinal crypts to form specialized organoids highly enriched in intestinal stem cells (ISCs), absorptive ENTs, secretory goblet cells, or Paneth cells. The morphological and morphometric characteristics of these cells in organoids were similar to those in vivo. The expression of certain TJ proteins varied with cell type: occludin and tricellulin levels were high in both ISCs and Paneth cells, while claudin-1, -2, and -7 expression was greatest in Paneth cells, ISCs, and ENTs, respectively. In contrast, the distribution of claudin-15, zonula occludens 1 (ZO-1), and E-cadherin was relatively homogeneous. E-cadherin and claudin-7 marked mainly the basolateral membrane, while claudin-2, ZO-1, and occludin resided in the apical membrane. Remarkably, organoids enriched in ENTs or goblet cells were over threefold more permeable to 4 and 10 kDa dextran compared to those containing stem and Paneth cells. The TJ-regulator larazotide prevented the approximately tenfold increases in dextran flux induced by the TJ-disrupter AT1002 into organoids of different cell types, indicating that this ZO toxin nonselectively increases permeability. Forced dedifferentiation of mature ENTs results in the reacquisition of ISC-like characteristics in TJ composition and dextran permeability, suggesting that the post-differentiation properties of TJs are not hardwired.ConclusionsDifferentiation of adult intestinal stem cells into mature secretory and absorptive cell types causes marked, but potentially reversible, changes in TJ composition, resulting in enhanced macromolecular permeability of the TJ leak pathway between ENTs and between goblet cells. This work advances our understanding of how cell differentiation affects the paracellular pathway of epithelia.
23204633
Secretion of microbicidal α-defensins by intestinal Paneth cells in response to bacteria
Paneth cells in mouse small intestinal crypts secrete granules rich in microbicidal peptides when exposed to bacteria or bacterial antigens. The dose-dependent secretion occurs within minutes and α-defensins, or cryptdins, account for 70% of the released bactericidal peptide activity. Gram-negative bacteria, Gram-positive bacteria, lipopolysaccharide, lipoteichoic acid, lipid A and muramyl dipeptide elicit cryptdin secretion. Live fungi and protozoa, however, do not stimulate degranulation. Thus intestinal Paneth cells contribute to innate immunity by sensing bacteria and bacterial antigens, and discharge microbicidal peptides at effective concentrations accordingly.
36197789
Paneth cell differentiation in the developing intestine of normal and transgenic mice.
Paneth cells represent one of the four major epithelial lineages in the mouse small intestine. It is the only lineage that migrates downward from the stem-cell zone located in the lower portion of the crypt of Lieberkühn to the crypt base. Mature Paneth cells release growth factors, digestive enzymes, and antimicrobial peptides from their apical secretory granules. Some of these factors may affect the crypt stem cell, its transit-cell descendants, differentiating villus-associated epithelial lineages, and/or the gut microflora. We used single and multilabel immunocytochemical methods to study Paneth cell differentiation during and after completion of gut morphogenesis in normal, gnotobiotic, and transgenic mice as well as in intestinal isografts. This lineage emerges coincident with cytodifferentiation of the fetal small intestinal endoderm, formation of crypts from an intervillus epithelium, and establishment of a stem-cell hierarchy. The initial differentiation program involves sequential expression of cryptdins, a phospholipase A2 (enhancing factor), and lysozyme. A dramatic increase in Paneth cell number per crypt occurs during postnatal days 14-28, when crypts proliferate by fission. Accumulation of fucosylated and sialylated glycoconjugates during this period represents the final evolution of the lineage's differentiation program. Establishment of this lineage is not dependent upon instructive interactions from the microflora. Transgenic mice containing nucleotides -6500 to +34 of the Paneth cell-specific mouse cryptdin 2 gene linked to the human growth hormone gene beginning at its nucleotide +3 inappropriately express human growth hormone in a large population of proliferating and nonproliferating cells in the intervillus epithelium up to postnatal day 5. Transgene expression subsequently becomes restricted to the Paneth cell lineage in the developing crypt. Cryptdin 2 nucleotides -6500 to +34 should be a useful marker of crypt morphogenesis and a valuable tool for conducting gain-of-function or loss-of-function experiments in Paneth cells.
4311453
Paneth cells constitute the niche for Lgr5 stem cells in intestinal crypts
Homeostasis of self-renewing small intestinal crypts results from neutral competition between Lgr5 stem cells, which are small cycling cells located at crypt bottoms. Lgr5 stem cells are interspersed between terminally differentiated Paneth cells that are known to produce bactericidal products such as lysozyme and cryptdins/defensins. Single Lgr5-expressing stem cells can be cultured to form long-lived, self-organizing crypt–villus organoids in the absence of non-epithelial niche cells. Here we find a close physical association of Lgr5 stem cells with Paneth cells in mice, both in vivo and in vitro. CD24+ Paneth cells express EGF, TGF-α, Wnt3 and the Notch ligand Dll4, all essential signals for stem-cell maintenance in culture. Co-culturing of sorted stem cells with Paneth cells markedly improves organoid formation. This Paneth cell requirement can be substituted by a pulse of exogenous Wnt. Genetic removal of Paneth cells in vivo results in the concomitant loss of Lgr5 stem cells. In colon crypts, CD24+ cells residing between Lgr5 stem cells may represent the Paneth cell equivalents. We conclude that Lgr5 stem cells compete for essential niche signals provided by a specialized daughter cell, the Paneth cell.
37478103
Intestinal absorption of water-soluble vitamins in health and disease.
Our knowledge of the mechanisms and regulation of intestinal absorption of water-soluble vitamins under normal physiological conditions, and of the factors/conditions that affect and interfere with theses processes has been significantly expanded in recent years as a result of the availability of a host of valuable molecular/cellular tools. Although structurally and functionally unrelated, the water-soluble vitamins share the feature of being essential for normal cellular functions, growth and development, and that their deficiency leads to a variety of clinical abnormalities that range from anaemia to growth retardation and neurological disorders. Humans cannot synthesize water-soluble vitamins (with the exception of some endogenous synthesis of niacin) and must obtain these micronutrients from exogenous sources. Thus body homoeostasis of these micronutrients depends on their normal absorption in the intestine. Interference with absorption, which occurs in a variety of conditions (e.g. congenital defects in the digestive or absorptive system, intestinal disease/resection, drug interaction and chronic alcohol use), leads to the development of deficiency (and sub-optimal status) and results in clinical abnormalities. It is well established now that intestinal absorption of the water-soluble vitamins ascorbate, biotin, folate, niacin, pantothenic acid, pyridoxine, riboflavin and thiamin is via specific carrier-mediated processes. These processes are regulated by a variety of factors and conditions, and the regulation involves transcriptional and/or post-transcriptional mechanisms. Also well recognized now is the fact that the large intestine possesses specific and efficient uptake systems to absorb a number of water-soluble vitamins that are synthesized by the normal microflora. This source may contribute to total body vitamin nutrition, and especially towards the cellular nutrition and health of the local colonocytes. The present review aims to outline our current understanding of the mechanisms involved in intestinal absorption of water-soluble vitamins, their regulation, the cell biology of the carriers involved and the factors that negatively affect these absorptive events.
1220297
Glial cells in the gut
Abstract   The enteric nervous system is composed of both neurons and glia. Recent evidence indicates that enteric glia–which vastly outnumber enteric neurons–are actively involved in the control of gastrointestinal functions: they contain neurotransmitter precursors, have the machinery for uptake and degradation of neuroligands, and express neurotransmitter‐receptors which makes them well suited as intermediaries in enteric neurotransmission and information processing in the ENS. Novel data further suggest that enteric glia have an important role in maintaining the integrity of the mucosal barrier of the gut. Finally, enteric glia may also serve as a link between the nervous and immune systems of the gut as indicated by their potential to synthesize cytokines, present antigen and respond to inflammatory insults. The role of enteric glia in human disease has not yet been systematically studied, but based on the available evidence it is predictable that enteric glia are involved in the etiopathogenesis of various pathological processes in the gut, particularly such with neuroinflammatory or neurodegenerative components.
20237536
IL‐1β and IL‐10 have dual effects on enteric glial cell proliferation
Inflammatory bowel disease is typically accompanied by functional and structural changes of the enteric nervous system. In pathological studies, cellular loss and axonal degeneration have been described in the myenteric plexus. However, more recent studies suggest that the proliferation rate of myenteric glial cells is enhanced in animal models of intestinal inflammation. Therefore, we have investigated the effect of different cytokines on the proliferative response of enteric glial cells (EGCs), comparing transformed enteric glial cell lines, primary astrocyte cultures and transformed oligodendrocytes. Cells were incubated in serum‐free chemically defined medium in the presence or absence of either interleukin (IL)‐1β or IL‐10 at concentrations ranging between 0.1 and 100 ng mL–1 for 48 h. Subsequently, [3H]thymidine was added to each culture dish for an additional 6 h, and the amount of incorporated [3H] was assessed. IL‐1β significantly and dose‐dependently suppressed [3H]‐uptake by EGCs. In contrast, IL‐10 induced a biphasic response; IL‐10 at low concentrations (0.1 ng mL–1) caused a significant suppression of [3H]‐uptake, whereas high concentrations (5–100 ng mL–1) significantly enhanced [3H] uptake. These results indicate that EGC proliferation can be modulated by cytokines. The differential effects of IL‐1β and IL‐10 suggest that during intestinal inflammation there may be a regulatory interplay between different classes of cytokines modulating EGC proliferation.
32606585
Lipopolysaccharides enhance the action of bradykinin in enteric neurons via secretion of interleukin‐1β from enteric glial cells
Functional changes of the enteric nervous system have been observed under inflammatory states of inflammatory bowel disease increasing the endotoxin level. The aim of the present study was to determine the effect of lipopolysaccharides (LPS) on myenteric neuron–glia interaction in vitro. We examined the increase of the intracellular Ca2+ concentration ([Ca2+]i) and the release of interleukin‐1β (IL‐1β) or prostaglandin E2 (PGE2) and COX‐2 expression in myenteric plexus cells from the rat intestine induced by LPS. LPS potentiated BK‐induced [Ca2+]i increases in both myenteric neurons and enteric glial cells, which were suppressed by a B1R antagonist. Only in enteric glial cells, a B1R agonist increased [Ca2+]i. The effects of LPS were blocked by pretreatment with an interleukin‐1 receptor antagonist or by reducing the density of enteric glial cells in culture. LPS prompted the release of IL‐1β from enteric glial cells. The augmenting effects of IL‐1β on the BK‐induced neural [Ca2+]i increase and PGE2 release from enteric glial cells were abolished by a phospholipase A2 (PLA2) inhibitor and a COX inhibitor, and partly suppressed by a COX‐2 inhibitor. IL‐1β up‐regulated the COX‐2 expression in enteric glial cells. LPS promotes IL‐1β secretion from enteric glial cells, resulting in augmentation of the neural response to BK through PGE2 release via glial PLA2 and COX‐2. The alteration of the regulatory effect of glial cells may be the cause of the changes in neural function in the enteric nervous system in inflammatory bowel disease. © 2009 Wiley‐Liss, Inc.
30220237
Enteric glia regulate intestinal barrier function and inflammation via release of S-nitrosoglutathione.
BACKGROUND & AIMS
Barrier functions across epithelia and endothelia are essential for homeostatic tissue regulation. Astroglia interact with cerebral endothelia to maintain the blood-brain barrier. Whether similar interactions between astrocyte-like enteric glia and epithelia regulate intestinal barrier function is not known.


METHODS
Fluorescent permeability markers were used to measure intestinal barrier function in vivo after conditional ablation of enteric glia in transgenic mice. Enteric glial cell regulation of epithelial barrier integrity then was modeled in vitro using coculture. Glial-derived barrier-inducing factors were characterized using size-exclusion chromatography and mass spectrometry. Epithelial barrier integrity was assessed by transepithelial resistance readings and by quantitative measurement of tight-junction-associated protein expression by quantitative polymerase chain reaction and Western blot.


RESULTS
We show that ablation of enteric glial cells in transgenic mice causes intestinal mucosal barrier dysfunction, resulting in inflammation. Glial-derived s-nitrosoglutathione (GSNO) was identified as a potent inducer of mucosal barrier function in vitro and in vivo and of attenuated tissue inflammation after ablation of enteric glia in transgenic mice. GSNO regulation of mucosal barrier function was associated directly with an increased expression of perijunctional F-actin and tight-junction-associated proteins zonula occludens-1 and occludin. GSNO also significantly restored mucosal barrier function in colonic biopsy specimens from patients with Crohn's disease, a well-described inflammatory permeability disorder associated with enteric glial-cell disruption.


CONCLUSIONS
Enteric glia therefore share the ability of astrocytes to regulate tight-junction integrity, and cellular interactions comparable with those maintaining blood-brain barrier function also regulate epithelial permeability at mucosal surfaces.
23245961
Isolation, identification, and culture of normal mouse colonic glia
We have developed a novel method of isolating and culturing murine colonic mucosal glial cells. Two morphologies are appreciated, a small flat bi or tri polar cell and a larger multipolar cell. The glial cultures have been freed of contaminating fibroblasts and epithelial cells and have been passaged by trypsinization. By intermediate filament (IF) typing, the glial cells have been further characterized as astrocyte‐like. All cells expressed glial fibrillary acid protein but not neurofilament 160 protein. The glial cultures expressed the neuropeptides, substance P and substance K. Central nervous system astrocytes synthesize neuropeptides, prostaglandins and cytokines, and can express major histocompatibility class II antigens. It is likely that enteric mucosal glia will also prove to have varied functions. These cultures can now be used to define the role of enteric mucosal glia and to further study their complex interaction with other cells of the colonic mucosa.
42100492
Colonization of the bowel by the precursors of enteric glia: Studies of normal and congenitally aganglionic mutant mice
The terminal portion of the ls/ls mouse is congenitally aganglionic because the precursors of enteric neurons fail to enter this region. This animal was studied in order to gain insight into the origin of enteric glia and into the process by which the precursors of these cells colonize the gut. In control (CD‐1) mice, immunoreactivity of the glial marker, glial fibrillary acidic protein, appeared for the first time in the fetal bowel at day E16 and, in adults, was much more intense within intraenteric neural elements than in nerves outside the bowel. Glial fibrillary acidic protein developed in tissue cultures of fetal intestine explanted before the protein appeared in situ, and before the bowel became innervated by extrinsic nerves; thus, the precursors of cells able to elaborate glial fibrillary acidic protein must have been present, but unrecognizable, in the original explants. This explant assay demonstrated that these glial precursors were present in all regions of the bowel of control mice, but not in the presumptive aganglionic bowel of ls/ls mice. The nerves (of extrinsic origin) in the aganglionic tissue of ls/ls mice showed a high level of immunoreactive glial fibrillary acidic protein; nevertheless, their ultrastructure was typical of peripheral nerve, not enteric plexus, and they contained Schwann cells, not enteric glia. These observations support the view that enteric glia are derived from the single wave of neural crest colonists that populates the enteric nervous system before the gut receives its extrinsic innervation. These glial precursors, like neuronal precursors, tend to be excluded from the presumptive aganglionic ls/ls bowel. In contrast, Schwann cells grow into the abnormal ls/ls gut with the extrinsic innervation. The enteric microenvironment appears to promote the expression of glial fibrillary acidic protein in both enteric glia and Schwann cells; however, even within the bowel, Schwann cells retain their characteristic morphology. It is thus probable that the normal enteric nervous system contains supporting cells of separate lineages, enteric glia and Schwann cells.
40449660
Acquisition of neuronal and glial markers by neural crest–derived cells in the mouse intestine
Enteric neurons and glia arise from the neural crest. The phenotype of crest‐derived cells was examined as they differentiated into neurons or glia in the mouse small and large intestine. Previous studies have shown that undifferentiated enteric crest–derived cells are Phox2b+/Ret+/p75+/Sox10+, and at embryonic day (E) 10.5, about 10–15% of the crest‐derived cells in the small intestine have started to differentiate into neurons. In the current study, by E12.5 and E14.5, about 25% and 47%, respectively, of Phox2b+ cells in the small intestine were immunoreactive to the pan‐neuronal protein, ubitquitin hydrolase (PGP9.5), and the percentage did not change dramatically from E14.5 onward. The differentiation of crest‐derived cells into neurons in the colon lagged behind that in the small intestine by several days. Differentiating enteric neurons showed high Ret, low p75, and undetectable Sox10 immunostaining. Glial precursors were identified by the presence of brain‐specific fatty acid binding protein (B‐FABP) and detected first in the fore‐ and rostral midgut at E11.5. Glial precursors appeared to be B‐FABP+/Sox10+/p75+ but showed low Ret immunostaining. S100b was not detected until E14.5. Adult glial cells were B‐FABP+/Sox10+/p75+/S100b+. A nucleic acid stain (to identify all ganglion cells) was combined with immunostaining for PGP9.5 and S100b to detect neurons and glial cells, respectively, in the postnatal intestine. At postnatal day 0, fewer than 5% and 10% of cells in myenteric ganglia of the small and large intestine, respectively, were neither PGP9.5+ nor S100b+. Because some classes of neurons are not present in significant numbers until after birth, the expression of PGP9.5 by developing enteric neurons appeared to precede the expression of neuron type–specific markers. J. Comp. Neurol. 456:1–11, 2003. © 2002 Wiley‐Liss, Inc.
34066966
Advances in ontogeny of the enteric nervous system
Abstract  The neurons and glia that comprise the enteric nervous system (ENS), the intrinsic innervation of the gastrointestinal tract, are derived from vagal and sacral regions of the neural crest. In order to form the ENS, neural crest‐derived precursors undergo a number of processes including survival, migration and proliferation, prior to differentiation into neuronal subtypes, some of which form functional connections with the gut smooth muscle. Investigation of the developmental processes that underlie ENS formation has progressed dramatically in recent years, in no small part due to the attention of scientists from a range of disciplines on the genesis of Hirschsprung's disease (aganglionic megacolon), the major congenital abnormality of the ENS. This review summarizes recent advances in the field of early ENS ontogeny and focuses on: (i) the spatiotemporal migratory pathways followed by vagal and sacral neural crest‐derived ENS precursors, including recent in vivo imaging of migrating crest cells within the gut, (ii) the roles of the RET and EDNRB signalling pathways and how these pathways interact to control ENS development, and (iii) how perpendicular migrations of neural crest cells within the gut lead to the formation of the myenteric and submucosal plexi located between the smooth muscle layers of the gut wall.
34295490
Cell-Specific Transcriptional Profiling Reveals Candidate Mechanisms Regulating Development and Function of Uterine Epithelia in Mice
ABSTRACT All mammalian uteri have luminal (LE) and glandular epithelia (GE) in their endometrium. The LE mediates uterine receptivity and blastocyst attachment for implantation, and the GE synthesize and secrete or transport bioactive substances involved in blastocyst implantation, uterine receptivity, and stromal cell decidualization. However, the mechanisms governing uterine epithelial development after birth and their function in the adult are not fully understood. Here, comprehensive microarray analysis was conducted on LE and GE isolated by laser capture microdissection from uteri on Postnatal Day 10 (PD 10) and day of pseudopregnancy (DOPP) 2.5 and 3.5. This data was integrated with analysis of uteri from gland-containing control and aglandular progesterone-induced uterine gland knockout mice from PD 10 and DOPP 3.5. Many genes were expressed in both epithelia, but there was greater expression of genes in the LE than in the GE. In the neonate, GE-expressed genes were enriched for morphogenesis, development, migration, and retinoic acid signaling. In the adult, LE-expressed genes were enriched for metabolic processes and steroid biosynthesis, whereas retinoid signaling, tight junction, extracellular matrix, and regulation of kinase activity were enriched in the GE. The transcriptome differences in the epithelia support the idea that each cell type has a distinct and complementary function in the uterus. The candidate genes and regulatory networks identified here provide a framework to discover new mechanisms regulating development of epithelia in the postnatal uterus and their functions in early pregnancy.
22600918
Amniotic fluid inhibits Toll-like receptor 4 signaling in the fetal and neonatal intestinal epithelium
The fetal intestinal mucosa is characterized by elevated Toll-like receptor 4 (TLR4) expression, which can lead to the development of necrotizing enterocolitis (NEC)—a devastating inflammatory disease of the premature intestine—upon exposure to microbes. To define endogenous strategies that could reduce TLR4 signaling, we hypothesized that amniotic fluid can inhibit TLR4 signaling within the fetal intestine and attenuate experimental NEC, and we sought to determine the mechanisms involved. We show here that microinjection of amniotic fluid into the fetal (embryonic day 18.5) gastrointestinal tract reduced LPS-mediated signaling within the fetal intestinal mucosa. Amniotic fluid is abundant in EGF, which we show is required for its inhibitory effects on TLR4 signaling via peroxisome proliferator-activated receptor, because inhibition of EGF receptor (EGFR) with cetuximab or EGF-depleted amniotic fluid blocked the inhibitory effects of amniotic fluid on TLR4, whereas amniotic fluid did not prevent TLR4 signaling in EGFR- or peroxisome proliferator-activated receptor γ–deficient enterocytes or in mice deficient in intestinal epithelial EGFR, and purified EGF attenuated the exaggerated intestinal mucosal TLR4 signaling in wild-type mice. Moreover, amniotic fluid-mediated TLR4 inhibition reduced the severity of NEC in mice through EGFR activation. Strikingly, NEC development in both mice and humans was associated with reduced EGFR expression that was restored upon the administration of amniotic fluid in mice or recovery from NEC in humans, suggesting that a lack of amniotic fluid-mediated EGFR signaling could predispose to NEC. These findings may explain the unique susceptibility of premature infants to the development of NEC and offer therapeutic approaches to this devastating disease.
2416312
Spatial and temporal expression of an epithelial mucin, Muc-1, during mouse development.
The Muc-1 mucin is found as a transmembrane protein in the apical surface of glandular epithelia. To provide insight into possible functions, we have assessed the timing of expression and the distribution of the Muc-1 protein during mouse embryogenesis using three different techniques: RT-PCR, northern blots and immunohistochemistry. Our results indicate that Muc-1 expression correlates with epithelial differentiation in stomach, pancreas, lung, trachea, kidney and salivary glands. Once started, Muc-1 synthesis continually increases with time, mainly due to epithelial area growth. Our data suggest that expression of the Muc-1 gene is under spatial and temporal control during organogenesis. Although Muc-1 is present in different organs, its expression is not induced systemically, but according to the particular onset of epithelial polarization and branching morphogenesis of each individual organ. It is of particular interest that Muc-1 protein can be detected lining the apical surfaces of the developing lumens when the epithelium of these organs is still undergoing folding and branching, and glandular activity has not yet started. We speculate that Muc-1 may participate in epithelial sheet differentiation/lumen formation during early development of the organs known to express it. This speculation is based on: (1) the detection of Muc-1 expression early during organogenesis, (2) the defined apical localization in different epithelia, (3) the decrease in cell-cell interactions when Muc-1 protein is highly expressed and (4) the possible interaction of its cytoplasmic tail with the actin cytoskeleton. However, it remains to be established using in vitro systems, whether the temporal and local expression of the Muc-1 gene coincident with the morphogenetic events described here is relevant for the process.
28653615
The Sox transcriptional factors: Functions during intestinal development in vertebrates.
The intestine has long been studied as a model for adult stem cells due to the life-long self-renewal of the intestinal epithelium through the proliferation of the adult intestinal stem cells. Recent evidence suggests that the formation of adult intestinal stem cells in mammals takes place during the thyroid hormone-dependent neonatal period, also known as postembryonic development, which resembles intestinal remodeling during frog metamorphosis. Studies on the metamorphosis in Xenopus laevis have revealed that many members of the Sox family, a large family of DNA binding transcription factors, are upregulated in the intestinal epithelium during the formation and/or proliferation of the intestinal stem cells. Similarly, a number of Sox genes have been implicated in intestinal development and pathogenesis in mammals. Futures studies are needed to determine the expression and potential involvement of this important gene family in the development of the adult intestinal stem cells. These include the analyses of the expression and regulation of these and other Sox genes during postembryonic development in mammals as well as functional investigations in both mammals and amphibians by using the recently developed gene knockout technologies.
19576530
Expression of Cdx‐2 in the mouse embryo and placenta: Possible role in patterning of the extra‐embryonic membranes
Three mouse homologues of the Drosophila homeotic gene Caudal (Cad) have been described. They are currently designated Cdx‐1, Cdx‐2, and Cdx‐4. Cdx‐1 and 2 are both strongly expressed in the adult mid‐ and hindgut, while Cdx‐1 and 4 have been shown to be activated in the embryonic primitive streak. Using a polyclonal antibody against a fusion protein containing the amino terminal 109 amino acids of murine Cdx‐2, we here describe the topographical location of the gene product from early cleavage to 12.5 days of embryonic development. Cdx‐2 expression begins at 3.5 days and is confined to the trophectoderm, being absent from the inner cell mass. Subsequently, staining is located in the extra‐embryonic ectoderm adjacent to the epiblast, but sparing the more superficially placed polar, as well as the mural trophoblastic cells. Continuing expression in the fetal membranes involves the chorion, the allantoic bud, and, at even later stages, the spongiotrophoblast. From 8.5 days, Cdx‐2 begins to be expressed in embryonic tissues, principally (unlike Cdx‐1) in the posterior part of the gut from its earliest formation, as well as in the tail bud and in the caudal part of the neural tube. Cdx‐2 is, therefore, transcribed well before any other membrane of the Cad homologue group and of the related Hox‐C group; its expression in the extra‐embryonic membranes and in the hindgut reflects the phylogenetic relationship between the cloaca and the chorio‐allantois and suggests the possibility that homeobox genes may be involved in placental development and/or patterning. © 1995 wiley‐Liss, Inc.
4472503
Persistent Gut Microbiota Immaturity in Malnourished Bangladeshi Children
Therapeutic food interventions have reduced mortality in children with severe acute malnutrition (SAM), but incomplete restoration of healthy growth remains a major problem. The relationships between the type of nutritional intervention, the gut microbiota, and therapeutic responses are unclear. In the current study, bacterial species whose proportional representation define a healthy gut microbiota as it assembles during the first two postnatal years were identified by applying a machine-learning-based approach to 16S ribosomal RNA data sets generated from monthly faecal samples obtained from birth onwards in a cohort of children living in an urban slum of Dhaka, Bangladesh, who exhibited consistently healthy growth. These age-discriminatory bacterial species were incorporated into a model that computes a ‘relative microbiota maturity index’ and ‘microbiota-for-age Z-score’ that compare postnatal assembly (defined here as maturation) of a child’s faecal microbiota relative to healthy children of similar chronologic age. The model was applied to twins and triplets (to test for associations of these indices with genetic and environmental factors, including diarrhoea), children with SAM enrolled in a randomized trial of two food interventions, and children with moderate acute malnutrition. Our results indicate that SAM is associated with significant relative microbiota immaturity that is only partially ameliorated following two widely used nutritional interventions. Immaturity is also evident in less severe forms of malnutrition and correlates with anthropometric measurements. Microbiota maturity indices provide a microbial measure of human postnatal development, a way of classifying malnourished states, and a parameter for judging therapeutic efficacy. More prolonged interventions with existing or new therapeutic foods and/or addition of gut microbes may be needed to achieve enduring repair of gut microbiota immaturity in childhood malnutrition and improve clinical outcomes.
2990026
Diet rapidly and reproducibly alters the human gut microbiome
Long-term dietary intake influences the structure and activity of the trillions of microorganisms residing in the human gut, but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids and the outgrowth of microorganisms capable of triggering inflammatory bowel disease. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles.
4400297
An obesity-associated gut microbiome with increased capacity for energy harvest
The worldwide obesity epidemic is stimulating efforts to identify host and environmental factors that affect energy balance. Comparisons of the distal gut microbiota of genetically obese mice and their lean littermates, as well as those of obese and lean human volunteers have revealed that obesity is associated with changes in the relative abundance of the two dominant bacterial divisions, the Bacteroidetes and the Firmicutes. Here we demonstrate through metagenomic and biochemical analyses that these changes affect the metabolic potential of the mouse gut microbiota. Our results indicate that the obese microbiome has an increased capacity to harvest energy from the diet. Furthermore, this trait is transmissible: colonization of germ-free mice with an ‘obese microbiota’ results in a significantly greater increase in total body fat than colonization with a ‘lean microbiota’. These results identify the gut microbiota as an additional contributing factor to the pathophysiology of obesity.
205230992
Functional interactions between the gut microbiota and host metabolism
The link between the microbes in the human gut and the development of obesity, cardiovascular disease and metabolic syndromes, such as type 2 diabetes, is becoming clearer. However, because of the complexity of the microbial community, the functional connections are less well understood. Studies in both mice and humans are helping to show what effect the gut microbiota has on host metabolism by improving energy yield from food and modulating dietary or the host-derived compounds that alter host metabolic pathways. Through increased knowledge of the mechanisms involved in the interactions between the microbiota and its host, we will be in a better position to develop treatments for metabolic disease.
2990026
Diet rapidly and reproducibly alters the human gut microbiome
Long-term dietary intake influences the structure and activity of the trillions of microorganisms residing in the human gut, but it remains unclear how rapidly and reproducibly the human gut microbiome responds to short-term macronutrient change. Here we show that the short-term consumption of diets composed entirely of animal or plant products alters microbial community structure and overwhelms inter-individual differences in microbial gene expression. The animal-based diet increased the abundance of bile-tolerant microorganisms (Alistipes, Bilophila and Bacteroides) and decreased the levels of Firmicutes that metabolize dietary plant polysaccharides (Roseburia, Eubacterium rectale and Ruminococcus bromii). Microbial activity mirrored differences between herbivorous and carnivorous mammals, reflecting trade-offs between carbohydrate and protein fermentation. Foodborne microbes from both diets transiently colonized the gut, including bacteria, fungi and even viruses. Finally, increases in the abundance and activity of Bilophila wadsworthia on the animal-based diet support a link between dietary fat, bile acids and the outgrowth of microorganisms capable of triggering inflammatory bowel disease. In concert, these results demonstrate that the gut microbiome can rapidly respond to altered diet, potentially facilitating the diversity of human dietary lifestyles.
2611652
Impact of high-fat diet on the intestinal microbiota and small intestinal physiology before and after the onset of obesity.
The modulation of the intestinal microbiota by high-fat diet (HFD) has a major impact on both immunological and metabolic functions of the host. Taking this into consideration, the aim of this contribution is to review the impact of HFD on microbiota profile and small intestinal physiology before and after the onset of obesity and its metabolic complications. Evidence from animal studies suggest that before the onset of obesity and its metabolic complications, HFD induces intestinal dysbiosis - encompassing changes in composition balance and massive redistribution with bacteria occupying intervillous spaces and crypts - associated with early physiopathological changes, predominantly in the ileum, such as low-grade inflammation, decreased antimicrobial peptides expression, impaired mucus production, secretion and layer's thickness, and decreased expression of tight junction proteins. With time, major inflammatory signals (e.g. toll-like receptor-4 dependent) become activated, thereby stimulating proinflammatory cytokines secretion in the small intestine. This inflammatory state might subsequently exacerbate disruption of the mucus layer barrier and increase epithelial permeability of the small intestine, thereby creating an environment that facilitates the passage of bacterial components (e.g. lipopolysaccharide, peptidoglycan and flagellin) and metabolites from the intestinal lumen (e.g. secondary bile acids) to the circulation and peripheral tissues (i.e. leaky gut), eventually promoting the development of systemic inflammation, obesity, adiposity, insulin resistance and glucose intolerance preceding hyperglycemia. Although the mechanisms are still not completely understood, prebiotics, probiotics, polyphenols, peroxisome proliferator-activated receptor-γ agonists (such as rosiglitazone) and exercise have been shown to reverse HFD-induced intestinal phenotype and to attenuate the severity of obesity and its associated metabolic complications.
22397144
Alterations of gut barrier and gut microbiota in food restriction, food deprivation and protein-energy wasting.
Increasing evidence shows that gut microbiota composition is related to changes of gut barrier function including gut permeability and immune function. Gut microbiota is different in obese compared to lean subjects, suggesting that gut microbes are also involved in energy metabolism and subsequent nutritional state. While research on gut microbiota and gut barrier has presently mostly focused on intestinal inflammatory bowel diseases and more recently on obesity and type 2 diabetes, this review aims at summarizing the present knowledge regarding the impact, in vivo, of depleted nutritional states on structure and function of the gut epithelium, the gut-associated lymphoid tissue (GALT), the gut microbiota and the enteric nervous system. It highlights the complex interactions between the components of gut barrier in depleted states due to food deprivation, food restriction and protein energy wasting and shows that these interactions are multidirectional, implying the existence of feedbacks.
35670292
Obesogenic diet-induced gut barrier dysfunction and pathobiont expansion aggravate experimental colitis
Consumption of a typical Western diet is a risk factor for several disorders. Metabolic syndrome is the most common disease associated with intake of excess fat. However, the incidence of inflammatory bowel disease is also greater in subjects consuming a Western diet, although the mechanism of this phenomenon is not clearly understood. We examined the morphological and functional changes of the intestine, the first site contacting dietary fat, in mice fed a high-fat diet (HFD) inducing obesity. Paneth cell area and production of antimicrobial peptides by Paneth cells were decreased in HFD-fed mice. Goblet cell number and secretion of mucin by goblet cells were also decreased, while intestinal permeability was increased in HFD-fed mice. HFD-fed mice were more susceptible to experimental colitis, and exhibited severe colonic inflammation, accompanied by the expansion of selected pathobionts such as Atopobium sp. and Proteobacteria. Fecal microbiota transplantation transferred the susceptibility to DSS-colitis, and antibiotic treatment abrogated colitis progression. These data suggest that an experimental HFD-induced Paneth cell dysfunction and subsequent intestinal dysbiosis characterized by pathobiont expansion can be predisposing factors to the development of inflammatory bowel disease.
22724062
Starvation compromises Paneth cells.
Lack of enteral feeding, with or without parenteral nutritional support, is associated with increased intestinal permeability and translocation of bacteria. Such translocation is thought to be important in the high morbidity and mortality rates of patients who receive nothing by mouth. Recently, Paneth cells, important constituents of innate intestinal immunity, were found to be crucial in host protection against invasion of both commensal and pathogenic bacteria. This study investigates the influence of food deprivation on Paneth cell function in a mouse starvation model. Quantitative PCR showed significant decreases in mRNA expression of typical Paneth cell antimicrobials, lysozyme, cryptdin, and RegIIIγ, in ileal tissue after 48 hours of food deprivation. Protein expression levels of lysozyme and RegIIIγ precursor were also significantly diminished, as shown by Western blot analysis and IHC. Late degenerative autophagolysosomes and aberrant Paneth cell granules in starved mice were evident by electron microscopy, Western blot analysis, and quantitative PCR. Furthermore, increased bacterial translocation to mesenteric lymph nodes coincided with Paneth cell abnormalities. The current study demonstrates the occurrence of Paneth cell abnormalities during enteral starvation. Such changes may contribute to loss of epithelial barrier function, causing the apparent bacterial translocation in enteral starvation.
45991269
Diet‐induced obesity has neuroprotective effects in murine gastric enteric nervous system: involvement of leptin and glial cell line‐derived neurotrophic factor
Non‐technical summary  The enteric nervous system (ENS) is an autonomous nervous system integrated along the gut that controls major gastrointestinal (GI) functions such as motility. Increasing data have demonstrated that nutritional factors can modulate the ENS phenotype and consequently impact upon GI functions. Western diet is central in the development of obesity but surprisingly no study has characterized its impact upon ENS phenotype and functions. We show that Western diet‐induced obesity (DIO) prevented age‐associated loss in a specific population of enteric neurons leading to an acceleration of gastric emptying. In addition, we showed that neuroprotective effects of DIO likely involved leptin and glial cell line‐derived neurotrophic factor (GDNF). This is the first study demonstrating an impact of DIO upon the ENS. These DIO‐induced neuroplastic changes in the ENS could be involved in the physiopathology of obesity.
53771035
High-Fat Diet During the Perinatal Period Induces Loss of Myenteric Nitrergic Neurons and Increases Enteric Glial Density, Prior to the Development of Obesity
Diet-induced obesity induces peripheral inflammation accompanied by a loss of myenteric neurons. Few studies, however, have investigated the effects of a high-fat diet (HFD) on either the development of myenteric neurons or prior to the occurrence of obesity. The present study assessed the effects of maternal HFD on the density and neurochemical phenotype of myenteric ganglia in the upper gastrointestinal tract. Sprague-Dawley rats were fed either a control or HFD (14% or 60% kcal from fat, respectively) from embryonic day 13; the fundus, corpus and duodenum were fixed thereafter at postnatal 2, 4, 6 and 12 weeks of age for subsequent immunohistochemical studies. While myenteric ganglion size did not differ throughout the study, HFD exposure decreased the number of nitrergic neurons by 6 weeks of age in all regions. This decrease was accompanied by a loss of PGP-immunoreactive neurons, suggesting a decline in myenteric neuronal number. HFD also increased myenteric plexus glial cell density in all regions by 4 weeks of age. These changes occurred in the absence of an increase in serum or gastric inflammatory markers. The present study suggests that exposure to a HFD during the perinatal time period results in glial proliferation and loss of inhibitory nitrergic neurons prior to the onset of obesity, suggesting that dietary alterations may affect gastrointestinal functions independently of increased adiposity or glycemic dysregulation.
3587483
Worldwide trends in body-mass index, underweight, overweight, and obesity from 1975 to 2016: a pooled analysis of 2416 population-based measurement studies in 128·9 million children, adolescents, and adults
Summary Background Underweight, overweight, and obesity in childhood and adolescence are associated with adverse health consequences throughout the life-course. Our aim was to estimate worldwide trends in mean body-mass index (BMI) and a comprehensive set of BMI categories that cover underweight to obesity in children and adolescents, and to compare trends with those of adults. Methods We pooled 2416 population-based studies with measurements of height and weight on 128·9 million participants aged 5 years and older, including 31·5 million aged 5–19 years. We used a Bayesian hierarchical model to estimate trends from 1975 to 2016 in 200 countries for mean BMI and for prevalence of BMI in the following categories for children and adolescents aged 5–19 years: more than 2 SD below the median of the WHO growth reference for children and adolescents (referred to as moderate and severe underweight hereafter), 2 SD to more than 1 SD below the median (mild underweight), 1 SD below the median to 1 SD above the median (healthy weight), more than 1 SD to 2 SD above the median (overweight but not obese), and more than 2 SD above the median (obesity). Findings Regional change in age-standardised mean BMI in girls from 1975 to 2016 ranged from virtually no change (−0·01 kg/m2 per decade; 95% credible interval −0·42 to 0·39, posterior probability [PP] of the observed decrease being a true decrease=0·5098) in eastern Europe to an increase of 1·00 kg/m2 per decade (0·69–1·35, PP>0·9999) in central Latin America and an increase of 0·95 kg/m2 per decade (0·64–1·25, PP>0·9999) in Polynesia and Micronesia. The range for boys was from a non-significant increase of 0·09 kg/m2 per decade (−0·33 to 0·49, PP=0·6926) in eastern Europe to an increase of 0·77 kg/m2 per decade (0·50–1·06, PP>0·9999) in Polynesia and Micronesia. Trends in mean BMI have recently flattened in northwestern Europe and the high-income English-speaking and Asia-Pacific regions for both sexes, southwestern Europe for boys, and central and Andean Latin America for girls. By contrast, the rise in BMI has accelerated in east and south Asia for both sexes, and southeast Asia for boys. Global age-standardised prevalence of obesity increased from 0·7% (0·4–1·2) in 1975 to 5·6% (4·8–6·5) in 2016 in girls, and from 0·9% (0·5–1·3) in 1975 to 7·8% (6·7–9·1) in 2016 in boys; the prevalence of moderate and severe underweight decreased from 9·2% (6·0–12·9) in 1975 to 8·4% (6·8–10·1) in 2016 in girls and from 14·8% (10·4–19·5) in 1975 to 12·4% (10·3–14·5) in 2016 in boys. Prevalence of moderate and severe underweight was highest in India, at 22·7% (16·7–29·6) among girls and 30·7% (23·5–38·0) among boys. Prevalence of obesity was more than 30% in girls in Nauru, the Cook Islands, and Palau; and boys in the Cook Islands, Nauru, Palau, Niue, and American Samoa in 2016. Prevalence of obesity was about 20% or more in several countries in Polynesia and Micronesia, the Middle East and north Africa, the Caribbean, and the USA. In 2016, 75 (44–117) million girls and 117 (70–178) million boys worldwide were moderately or severely underweight. In the same year, 50 (24–89) million girls and 74 (39–125) million boys worldwide were obese. Interpretation The rising trends in children's and adolescents' BMI have plateaued in many high-income countries, albeit at high levels, but have accelerated in parts of Asia, with trends no longer correlated with those of adults. Funding Wellcome Trust, AstraZeneca Young Health Programme.
12418148
Risk Factors, Incidence, and Morbidity Associated With Obstetric Clostridium difficile Infection.
OBJECTIVE
To evaluate the risk factors, incidence, and morbidity associated with the diagnosis of obstetric Clostridium difficile infection.


METHODS
We performed a retrospective cohort study on women admitted for delivery using the Healthcare Cost and Utilization Project Nationwide Inpatient Sample from the United States. The delivery admission records of pregnant women were reviewed between 1999 and 2013. After adjusting for demographic and clinical characteristics, we assessed risk factors for the diagnosis of C difficile infection using unconditional logistic regression.


RESULTS
Of the total 13,881,592 births in our cohort, we identified 2,757 (0.02%) admissions for delivery complicated by a diagnosis of C difficile infection. During the study period, the rate of C difficile infection diagnoses among women hospitalized for delivery doubled from 15 (95% CI 11.87-16.96) to 30 (24.42-31.78) per 100,000 deliveries per year (P<.001). Risk factors associated with the diagnosis of C difficile infection included age older than 35 years, multiple gestations, smoking, Crohn's disease, ulcerative colitis, long-term antibiotic use, pneumonia, pyelonephritis as well as cesarean or perineal wound infection. The diagnosis of C difficile infection in pregnancy was associated with a significant increase in maternal death (8.0/1,000 vs 0.1/1,000, adjusted odds ratio [OR] 56.8, 95% CI 35.8-90.1). Furthermore, there was an increase in sepsis (46.4/1,000 vs 0.6/1,000, adjusted OR 59.1, 95% CI 48.8-71.6), paralytic ileus (58.0/1,000 vs 1.5/1,000, adjusted OR 33.1, 95% CI 27.5-39.8), venous thromboembolism (38.4/1,000 vs 3.1/1,000, adjusted OR 8.1, 95% CI 6.5-10.2), and hospital stays greater than 2 weeks (173.0/1,000 vs 6.5,1,000, adjusted OR 24.3, 95% CI 21.6-27.4) among pregnant women with C difficile infection.


CONCLUSION
The diagnosis of C difficile infections in pregnancy has increased over the past 15 years and this diagnosis is associated with significant maternal morbidity and mortality.
37663636
Folate Production by Bifidobacteria as a Potential Probiotic Property
ABSTRACT The ability of 76 Bifidobacterium strains to produce folate was investigated. In order to evaluate folic acid productivity, bifidobacteria were cultivated in the folate-free semisynthetic medium SM7. Most of the tested strains needed folate for growth. The production and the extent of vitamin accumulation were not a function of species but were distinctive features of individual strains. Six strains among the 17 that grew without folate produced significantly higher concentrations of vitamin (between 41 and 82 ng ml−1). The effects of exogenous folate and p-aminobenzoic acid (PABA) concentrations on folate production were evaluated. In contrast to most of the other strains, the folate yield of B. adolescentis MB 239 was not negatively affected by either PABA or exogenous folic acid. Folate production by B. adolescentis MB 239 was studied in the pH range of the colonic environment, and a comparison of folate production on raffinose, lactose, and fructo-oligosaccharides, which belong to three important groups of fermentable intestinal carbon sources, was established. Differences in folate biosynthesis by B. adolescentis MB 239 were not observed as a function either of the pH or of the carbon source. Fecal culture experiments demonstrated that the addition of B. adolescentis MB 239 may increase the folate concentration in the colonic environment.
8336084
Metabolomics analysis reveals large effects of gut microflora on mammalian blood metabolites
Although it has long been recognized that the enteric community of bacteria that inhabit the human distal intestinal track broadly impacts human health, the biochemical details that underlie these effects remain largely undefined. Here, we report a broad MS-based metabolomics study that demonstrates a surprisingly large effect of the gut “microbiome” on mammalian blood metabolites. Plasma extracts from germ-free mice were compared with samples from conventional (conv) animals by using various MS-based methods. Hundreds of features were detected in only 1 sample set, with the majority of these being unique to the conv animals, whereas ≈10% of all features observed in both sample sets showed significant changes in their relative signal intensity. Amino acid metabolites were particularly affected. For example, the bacterial-mediated production of bioactive indole-containing metabolites derived from tryptophan such as indoxyl sulfate and the antioxidant indole-3-propionic acid (IPA) was impacted. Production of IPA was shown to be completely dependent on the presence of gut microflora and could be established by colonization with the bacterium Clostridium sporogenes. Multiple organic acids containing phenyl groups were also greatly increased in the presence of gut microbes. A broad, drug-like phase II metabolic response of the host to metabolites generated by the microbiome was observed, suggesting that the gut microflora has a direct impact on the drug metabolism capacity of the host. Together, these results suggest a significant interplay between bacterial and mammalian metabolism.
24129838
The Rationale for Probiotics Improving Reproductive Health and Pregnancy Outcome
Medical problems of most importance to reproductive health of women differ to some extent between the developed world and resource‐disadvantaged countries. Nevertheless, many share a common link in microbial involvement.
23674259
Maternal metabolic, immune, and microbial systems in late pregnancy vary with malnutrition in mice†
Abstract Malnutrition is a global threat to pregnancy health and impacts offspring development. Establishing an optimal pregnancy environment requires the coordination of maternal metabolic and immune pathways, which converge at the gut. Diet, metabolic, and immune dysfunctions have been associated with gut dysbiosis in the nonpregnant individual. In pregnancy, these states are associated with poor pregnancy outcomes and offspring development. However, the impact of malnutrition on maternal gut microbes, and their relationships with maternal metabolic and immune status, has been largely underexplored. To determine the impact of undernutrition and overnutrition on maternal metabolic status, inflammation, and the microbiome, and whether relationships exist between these systems, pregnant mice were fed either a normal, calorically restricted (CR), or a high fat (HF) diet. In late pregnancy, maternal inflammatory and metabolic biomarkers were measured and the cecal microbiome was characterized. Microbial richness was reduced in HF mothers although they did not gain more weight than controls. First trimester weight gain was associated with differences in the microbiome. Microbial abundance was associated with altered plasma and gut inflammatory phenotypes and peripheral leptin levels. Taxa potentially protective against elevated maternal leptin, without the requirement of a CR diet, were identified. Suboptimal dietary conditions common during pregnancy adversely impact maternal metabolic and immune status and the microbiome. HF nutrition exerts the greatest pressures on maternal microbial dynamics and inflammation. Key gut bacteria may mediate local and peripheral inflammatory events in response to maternal nutrient and metabolic status, with implications for maternal and offspring health. Summary Sentence Malnutrition alters immune and metabolic systems in pregnancy, and gut microbes may mediate the maternal response to these suboptimal dietary exposures.
19823199
Pregnancy-related changes in the maternal gut microbiota are dependent upon the mother's periconceptional diet
Shifts in the maternal gut microbiome have been implicated in metabolic adaptations to pregnancy. We investigated how pregnancy and diet interact to influence the composition of the maternal gut microbiota. Female C57BL/6 mice were fed either a control or a high fat diet for 8 weeks prior to mating. After confirmation of pregnancy, maternal weight gain and food intake were recorded. Fecal pellets were collected at 2 timepoints prior to mating (at the beginning of the experiment, and after 6 weeks of the specified diet) and at 4 timepoints during pregnancy (gestation day 0.5, 5.5, 10.5, and 15.5). The microbial composition and predicted metabolic functionality of the non-pregnant and pregnant gut was determined via sequencing of the variable 3 region of the 16S rRNA gene. Upon conception, differences in gut microbial communities were observed in both control and high fat-fed mice, including an increase in mucin-degrading bacteria. Control versus high fat-fed pregnant mice possessed the most profound changes to their maternal gut microbiota as indicated by statistically significant taxonomic differences. High fat-fed pregnant mice, when compared to control-fed animals, were found to be significantly enriched in microbes involved in metabolic pathways favoring fatty acid, ketone, vitamin, and bile synthesis. We show that pregnancy-induced changes in the female gut microbiota occur immediately at the onset of pregnancy, are vulnerable to modulation by diet, but are not dependent upon increases in maternal weight gain during pregnancy. High fat diet intake before and during pregnancy results in distinctive shifts in the pregnant gut microbiota in a gestational-age dependent manner and these shifts predict significant differences in the abundance of genes that favor lipid metabolism, glycolysis and gluconeogenic metabolic pathways over the course of pregnancy.
28154194
Enhanced offspring predisposition to steatohepatitis with maternal high-fat diet is associated with epigenetic and microbiome alterations
Objective Non-alcoholic fatty liver disease (NAFLD) is an important co-morbidity associated with obesity and a precursor to steatohepatitis. However, the contributions of gestational and early life influences on development of NAFLD and NASH remain poorly appreciated. Methods Two independent studies were performed to examine whether maternal over-nutrition via exposure to high fat diet (HFD) leads to exacerbated hepatic responses to post-natal HFD and methionine choline deficient (MCD) diets in the offspring. Offspring of both control diet- and HFD-fed dams were weaned onto control and HFD, creating four groups. Results When compared to their control diet-fed littermates, offspring of HF-dams weaned onto HFD gained greater body weight; had increased relative liver weight and showed hepatic steatosis and inflammation. Similarly, this group revealed significantly greater immune response and pro-fibrogenic gene expression via RNA-seq. In parallel, 7–8 week old offspring were challenged with either control or MCD diets for 3 weeks. Responses to MCD diets were also exacerbated due to maternal HFD as seen by gene expression of classical pro-fibrogenic genes. Quantitative genome-scale DNA methylation analysis of over 1 million CpGs showed persistent epigenetic changes in key genes in tissue development and metabolism (Fgf21, Ppargc1β) with maternal HFD and in cell adhesion and communication (VWF, Ephb2) in the combination of maternal HFD and offspring MCD diets. Maternal HFD also influenced gut microbiome profiles in offspring leading to a decrease in α-diversity. Linear regression analysis revealed association between serum ALT levels and Coprococcus, Coriobacteriacae, Helicobacterioceae and Allobaculum. Conclusion Our findings indicate that maternal HFD detrimentally alters epigenetic and gut microbiome pathways to favor development of fatty liver disease and its progressive sequelae.
3351351
Intestinal epithelial cells: regulators of barrier function and immune homeostasis
The abundance of innate and adaptive immune cells that reside together with trillions of beneficial commensal microorganisms in the mammalian gastrointestinal tract requires barrier and regulatory mechanisms that conserve host–microbial interactions and tissue homeostasis. This homeostasis depends on the diverse functions of intestinal epithelial cells (IECs), which include the physical segregation of commensal bacteria and the integration of microbial signals. Hence, IECs are crucial mediators of intestinal homeostasis that enable the establishment of an immunological environment permissive to colonization by commensal bacteria. In this Review, we provide a comprehensive overview of how IECs maintain host–commensal microbial relationships and immune cell homeostasis in the intestine.
7250162
Prenatal undernutrition permanently decreases enteric neuron number and sympathetic innervation of Auerbach's plexus in the rat.
The density of the sympathetic innervation and enteric neuron number in Auerbach's plexus has been investigated by glyoxylic acid histofluorescence and by enzyme histochemistry respectively, in the jejunum of adult rats whose mothers had undergone dietary restriction during the last two weeks of pregnancy. Enteric neuron numbers were reduced by 27% and the sympathetic innervation was more sparse, less regularly arranged and showed less fluorescence in the undernourished rats compared to control groups. These results indicate that the effects of maternal undernutrition on the sympathetic and enteric nervous systems are long lasting in the offspring and also that the terminal parts of the sympathetic neuron, as well as the cell body, are susceptible to a nutritional insult.
35798336
High-fat diet and age-dependent effects on enteric glial cell populations of mouse small intestine
Diabetes and obesity are increasing in prevalence at an alarming rate throughout the world. Autonomic diabetic neuropathy is evident in individuals that experience a long-standing diabetic disease state, and gastrointestinal (GI) dysmotility is thought to be the outcome of neuropathies within the enteric nervous system (ENS) of these patients. To date, an analysis of enteric glial cell population changes during diabetic symptoms has not been performed, and may bring insight into disease pathology and neuropathy, given glial cell implications in gastrointestinal and neuronal homeostasis. Diabetes and obesity were monitored in C57Bl/6J mice fed a 72% high-fat diet, and duodenal glial expression patterns were evaluated by immunohistochemistry and RT-PCR for S100β, Sox10 and GFAP proteins and transcripts, as well as transmission electron microscopy (TEM). The high-fat diet caused obesity, hyperglycemia and insulin resistance after 4 weeks. These changes were associated with a significant decline in the area density indices of mucosa-associated glial cell networks, evidenced by S100β staining at 8 and 20 weeks. All three markers and TEM showed that myenteric glial cells were unaffected by early and late disease periods. However, analysis of Sox10 transcript expression and immunoreactivity showed a diet independent, age-associated decline in glial cell populations. This is the first study showing that mucosal glia cell damage occurs during diabetic symptoms, suggesting that mucosal enteric glia injury may have a pathophysiological significance during this disease. Our results also provide support for age-associated changes in longitudinal studies of enteric glial cells.
1534055
High-fat diet modifies the PPAR-γ pathway leading to disruption of microbial and physiological ecosystem in murine small intestine
Significance Our study aimed at exploring the intersection of high-fat diet, mucosal immune defenses, and microbiota. It remains unclear how diet imbalance toward excessive fat intake leads to secondary pathological effects on host physiology through the microbiota. We show that a short period of consumption of high-fat diet alters the small-intestinal defenses and that the biochemistry of the ileum is drastically modified, leading to physiological changes close to that observed in cystic fibrosis. We identified peroxisome proliferator-activated receptor-γ as major regulator of mucosal defenses upon exposure to fat excess. As a result, our work provides a fundamental understanding of the underlying cause of severe chronic disorders associated with Western diet. Diet is among the most important factors contributing to intestinal homeostasis, and basic functions performed by the small intestine need to be tightly preserved to maintain health. Little is known about the direct impact of high-fat (HF) diet on small-intestinal mucosal defenses and spatial distribution of the microbiota during the early phase of its administration. We observed that only 30 d after HF diet initiation, the intervillous zone of the ileum—which is usually described as free of bacteria—became occupied by a dense microbiota. In addition to affecting its spatial distribution, HF diet also drastically affected microbiota composition with a profile characterized by the expansion of Firmicutes (appearance of Erysipelotrichi), Proteobacteria (Desulfovibrionales) and Verrucomicrobia, and decrease of Bacteroidetes (family S24-7) and Candidatus arthromitus. A decrease in antimicrobial peptide expression was predominantly observed in the ileum where bacterial density appeared highest. In addition, HF diet increased intestinal permeability and decreased cystic fibrosis transmembrane conductance regulator (Cftr) and the Na-K-2Cl cotransporter 1 (Nkcc1) gene and protein expressions, leading to a decrease in ileal secretion of chloride, likely responsible for massive alteration in mucus phenotype. This complex phenotype triggered by HF diet at the interface between the microbiota and the mucosal surface was reversed when the diet was switched back to standard composition or when mice were treated for 1 wk with rosiglitazone, a specific agonist of peroxisome proliferator-activated receptor-γ (PPAR-γ). Moreover, weaker expression of antimicrobial peptide-encoding genes and intervillous bacterial colonization were observed in Ppar-γ–deficient mice, highlighting the major role of lipids in modulation of mucosal immune defenses.
18820778
High Fat Diet-Induced Gut Microbiota Exacerbates Inflammation and Obesity in Mice via the TLR4 Signaling Pathway
Background & Aims While it is widely accepted that obesity is associated with low-grade systemic inflammation, the molecular origin of the inflammation remains unknown. Here, we investigated the effect of endotoxin-induced inflammation via TLR4 signaling pathway at both systemic and intestinal levels in response to a high-fat diet. Methods C57BL/6J and TLR4-deficient C57BL/10ScNJ mice were maintained on a low-fat (10 kcal % fat) diet (LFD) or a high–fat (60 kcal % fat) diet (HFD) for 8 weeks. Results HFD induced macrophage infiltration and inflammation in the adipose tissue, as well as an increase in the circulating proinflammatory cytokines. HFD increased both plasma and fecal endotoxin levels and resulted in dysregulation of the gut microbiota by increasing the Firmicutes to Bacteriodetes ratio. HFD induced the growth of Enterobecteriaceae and the production of endotoxin in vitro. Furthermore, HFD induced colonic inflammation, including the increased expression of proinflammatory cytokines, the induction of Toll-like receptor 4 (TLR4), iNOS, COX-2, and the activation of NF-κB in the colon. HFD reduced the expression of tight junction-associated proteins claudin-1 and occludin in the colon. HFD mice demonstrated higher levels of Akt and FOXO3 phosphorylation in the colon compared to the LFD mice. While the body weight of HFD-fed mice was significantly increased in both TLR4-deficient and wild type mice, the epididymal fat weight and plasma endotoxin level of HFD-fed TLR4-deficient mice were 69% and 18% of HFD-fed wild type mice, respectively. Furthermore, HFD did not increase the proinflammatory cytokine levels in TLR4-deficient mice. Conclusions HFD induces inflammation by increasing endotoxin levels in the intestinal lumen as well as in the plasma by altering the gut microbiota composition and increasing its intestinal permeability through the induction of TLR4, thereby accelerating obesity.
19300217
Propensity to high-fat diet-induced obesity in rats is associated with changes in the gut microbiota and gut inflammation.
Consumption of diets high in fat and calories leads to hyperphagia and obesity, which is associated with chronic "low-grade" systemic inflammation. Ingestion of a high-fat diet alters the gut microbiota, pointing to a possible role in the development of obesity. The present study used Sprague-Dawley rats that, when fed a high-fat diet, exhibit either an obesity-prone (DIO-P) or obesity-resistant (DIO-R) phenotype, to determine whether changes in gut epithelial function and microbiota are diet or obese associated. Food intake and body weight were monitored daily in rats maintained on either low- or high-fat diets. After 8 or 12 wk, tissue was removed to determine adiposity and gut epithelial function and to analyze the gut microbiota using PCR. DIO-P but not DIO-R rats exhibit an increase in toll-like receptor (TLR4) activation associated with ileal inflammation and a decrease in intestinal alkaline phosphatase, a luminal enzyme that detoxifies lipopolysaccharide (LPS). Intestinal permeability and plasma LPS were increased together with phosphorylation of myosin light chain and localization of occludin in the cytoplasm of epithelial cells. Measurement of bacterial 16S rRNA showed a decrease in total bacterial density and an increase in the relative proportion of Bacteroidales and Clostridiales orders in high-fat-fed rats regardless of phenotype; an increase in Enterobacteriales was seen in the microbiota of DIO-P rats only. Consumption of a high-fat diet induces changes in the gut microbiota, but it is the development of inflammation that is associated with the appearance of hyperphagia and an obese phenotype.
3103094
Obesity alters gut microbial ecology.
We have analyzed 5,088 bacterial 16S rRNA gene sequences from the distal intestinal (cecal) microbiota of genetically obese ob/ob mice, lean ob/+ and wild-type siblings, and their ob/+ mothers, all fed the same polysaccharide-rich diet. Although the majority of mouse gut species are unique, the mouse and human microbiota(s) are similar at the division (superkingdom) level, with Firmicutes and Bacteroidetes dominating. Microbial-community composition is inherited from mothers. However, compared with lean mice and regardless of kinship, ob/ob animals have a 50% reduction in the abundance of Bacteroidetes and a proportional increase in Firmicutes. These changes, which are division-wide, indicate that, in this model, obesity affects the diversity of the gut microbiota and suggest that intentional manipulation of community structure may be useful for regulating energy balance in obese individuals. The sequences reported in this paper have been deposited in the GenBank database [accession nos. DQ 014552--DQ 015671 (mothers) and AY 989911--AY 993908 (offspring)].
2082429
Dietary fat and bile juice, but not obesity, are responsible for the increase in small intestinal permeability induced through the suppression of tight junction protein expression in LETO and OLETF rats
BackgroundAn increase in the intestinal permeability is considered to be associated with the inflammatory tone and development in the obesity and diabetes, however, the pathogenesis of the increase in the intestinal permeability is poorly understood. The present study was performed to determine the influence of obesity itself as well as dietary fat on the increase in intestinal permeability.MethodsAn obese rat strain, Otsuka Long Evans Tokushima Fatty (OLETF), and the lean counter strain, Long Evans Tokushima Otsuka (LETO), were fed standard or high fat diets for 16 weeks. Glucose tolerance, intestinal permeability, intestinal tight junction (TJ) proteins expression, plasma bile acids concentration were evaluated. In addition, the effects of rat bile juice and dietary fat, possible mediators of the increase in the intestinal permeability in the obesity, on TJ permeability were explored in human intestinal Caco-2 cells.ResultsThe OLETF rats showed higher glucose intolerance than did the LETO rats, which became more marked with the prolonged feeding of the high fat diet. Intestinal permeability in the OLETF rats evaluated by the urinary excretion of intestinal permeability markers (Cr-EDTA and phenolsulfonphthalein) was comparable to that in the LETO rats. Feeding the high fat diet increased intestinal permeability in both the OLETF and LETO rats, and the increases correlated with decreases in TJ proteins (claudin-1, claudin-3, occludin and junctional adhesion molecule-1) expression in the small, but not in the large intestine (cecum or colon). The plasma bile acids concentration was higher in rats fed the high fat diet. Exposure to bile juice and the fat emulsion increased TJ permeability with concomitant reductions in TJ protein expression (claudin-1, claudin-3, and junctional adhesion molecule-1) in the Caco-2 cell monolayers.ConclusionExcessive dietary fat and/or increased levels of luminal bile juice, but not genetic obesity, are responsible for the increase in small intestinal permeability resulting from the suppression of TJ protein expression.
17050352
Microbiome of prebiotic-treated mice reveals novel targets involved in host response during obesity
The gut microbiota is involved in metabolic and immune disorders associated with obesity and type 2 diabetes. We previously demonstrated that prebiotic treatment may significantly improve host health by modulating bacterial species related to the improvement of gut endocrine, barrier and immune functions. An analysis of the gut metagenome is needed to determine which bacterial functions and taxa are responsible for beneficial microbiota–host interactions upon nutritional intervention. We subjected mice to prebiotic (Pre) treatment under physiological (control diet: CT) and pathological conditions (high-fat diet: HFD) for 8 weeks and investigated the production of intestinal antimicrobial peptides and the gut microbiome. HFD feeding significantly decreased the expression of regenerating islet-derived 3-gamma (Reg3g) and phospholipase A2 group-II (PLA2g2) in the jejunum. Prebiotic treatment increased Reg3g expression (by ∼50-fold) and improved intestinal homeostasis as suggested by the increase in the expression of intectin, a key protein involved in intestinal epithelial cell turnover. Deep metagenomic sequencing analysis revealed that HFD and prebiotic treatment significantly affected the gut microbiome at different taxonomic levels. Functional analyses based on the occurrence of clusters of orthologous groups (COGs) of proteins also revealed distinct profiles for the HFD, Pre, HFD-Pre and CT groups. Finally, the gut microbiota modulations induced by prebiotics counteracted HFD-induced inflammation and related metabolic disorders. Thus, we identified novel putative taxa and metabolic functions that may contribute to the development of or protection against the metabolic alterations observed during HFD feeding and HFD-Pre feeding.
21175725
REG3γ-deficient mice have altered mucus distribution and increased mucosal inflammatory responses to the microbiota and enteric pathogens in the ileum
REG3γ is considered to have a protective role against infection with Gram-positive bacteria due to its bactericidal activity, but evidence from in vivo studies is lacking. We generated a REG3γ−/− mouse, and investigated the effect of lack of REG3γ on intestinal mucus distribution, spatial compartmentalization of bacteria, and expression of innate immunity genes. Infection studies were also performed with Gram-positive and Gram-negative pathogens to investigate the antimicrobial role of REG3γ. REG3γ−/− mice display altered mucus distribution, increased bacterial contact with the epithelium, and elevated inflammatory markers in the ileum without histological evidence of pathology. Infection response pathway genes were differentially expressed in both Listeria monocytogenes and Salmonella enteritidis infected REG3γ−/− and wild-type (wt) mice. Higher amounts of myeloperoxidase and interleukin-22 transcripts were present in the ileal mucosa of REG3γ−/− than wt mice, but translocation to the organs was unaffected. We concluded that REG3γ has a protective role against mucosal infection with pathogenic Listeria and Salmonella in vivo. REG3γ is equally distributed throughout the mucus and its absence results in increased epithelial contact with the microbiota resulting in low-grade inflammation. REG3γ can bind to Gram-negative and Gram-positive bacteria and influence mucus distribution in the ileum, properties which may contribute to mucosal protection.
24277591
Comparison of the microbicidal and muramidase activities of mouse lysozyme M and P.
Lysozyme is one of the most abundant antimicrobial proteins in the airspaces of the lung. Mice express two lysozyme genes, lysozyme M and P, but only the M enzyme is detected in abundance in lung tissues. Disruption of the lysozyme M locus significantly increased bacterial burden and mortality following intratracheal infection with a Gram-negative bacterium. Unexpectedly, significant lysozyme enzyme activity (muramidase activity) was detected in the airspaces of uninfected lysozyme M-/- mice, amounting to 25% of the activity in wild-type mice. Muramidase activity in lysozyme M-/- mice was associated with increased lysozyme P mRNA and protein in lung tissue and bronchoalveolar lavage fluid respectively. The muramidase activity of recombinant lysozyme P was less than that of recombinant M lysozyme. Recombinant P lysozyme was also less effective in killing selected Gram-negative bacteria, requiring higher concentrations than lysozyme M to achieve the same level of killing. The lower antimicrobial activity of P lysozyme, coupled with incomplete compensation by P lysozyme in lysozyme M-/- mice, probably accounts for the increased susceptibility of null mice to infection. Recombinant lysozyme M and P were equally effective in killing selected Gram-positive organisms. This outcome suggests that disruption of both M and P loci would significantly increase susceptibility to airway infections, particularly those associated with colonization by Gram-positive organisms.
33712909
Role of mucus layers in gut infection and inflammation.
The intestinal mucus is an efficient system for protecting the epithelium from bacteria by promoting their clearance and separating them from the epithelial cells, thereby inhibiting inflammation and infection. The function of the colon inner mucus layer is especially important as this explains how we can harbor the large number of bacteria in our gut. The major component of this mucus system is the MUC2 mucin which organizes the mucus by its enormously large net-like polymers. Pathogenic microorganisms, in turn, have developed mechanisms for circumventing this well-organized mucus protective system.
4465176
High-fat-diet-mediated dysbiosis promotes intestinal carcinogenesis independently of obesity
Several features common to a Western lifestyle, including obesity and low levels of physical activity, are known risk factors for gastrointestinal cancers. There is substantial evidence suggesting that diet markedly affects the composition of the intestinal microbiota. Moreover, there is now unequivocal evidence linking dysbiosis to cancer development. However, the mechanisms by which high-fat diet (HFD)-mediated changes in the microbial community affect the severity of tumorigenesis in the gut remain to be determined. Here we demonstrate that an HFD promotes tumour progression in the small intestine of genetically susceptible, K-rasG12Dint, mice independently of obesity. HFD consumption, in conjunction with K-ras mutation, mediated a shift in the composition of the gut microbiota, and this shift was associated with a decrease in Paneth-cell-mediated antimicrobial host defence that compromised dendritic cell recruitment and MHC class II molecule presentation in the gut-associated lymphoid tissues. When butyrate was administered to HFD-fed K-rasG12Dint mice, dendritic cell recruitment in the gut-associated lymphoid tissues was normalized, and tumour progression was attenuated. Importantly, deficiency in MYD88, a signalling adaptor for pattern recognition receptors and Toll-like receptors, blocked tumour progression. The transfer of faecal samples from HFD-fed mice with intestinal tumours to healthy adult K-rasG12Dint mice was sufficient to transmit disease in the absence of an HFD. Furthermore, treatment with antibiotics completely blocked HFD-induced tumour progression, suggesting that distinct shifts in the microbiota have a pivotal role in aggravating disease. Collectively, these data underscore the importance of the reciprocal interaction between host and environmental factors in selecting a microbiota that favours carcinogenesis, and they suggest that tumorigenesis is transmissible among genetically predisposed individuals.
6188944
Intestinal REG3 Lectins Protect against Alcoholic Steatohepatitis by Reducing Mucosa-Associated Microbiota and Preventing Bacterial Translocation.
Approximately half of all deaths from liver cirrhosis, the tenth leading cause of mortality in the United States, are related to alcohol use. Chronic alcohol consumption is accompanied by intestinal dysbiosis and bacterial overgrowth, yet little is known about the factors that alter the microbial composition or their contribution to liver disease. We previously associated chronic alcohol consumption with lower intestinal levels of the antimicrobial-regenerating islet-derived (REG)-3 lectins. Here, we demonstrate that intestinal deficiency in REG3B or REG3G increases numbers of mucosa-associated bacteria and enhances bacterial translocation to the mesenteric lymph nodes and liver, promoting the progression of ethanol-induced fatty liver disease toward steatohepatitis. Overexpression of Reg3g in intestinal epithelial cells restricts bacterial colonization of mucosal surfaces, reduces bacterial translocation, and protects mice from alcohol-induced steatohepatitis. Thus, alcohol appears to impair control of the mucosa-associated microbiota, and subsequent breach of the mucosal barrier facilitates progression of alcoholic liver disease.
12801372
The Antibacterial Lectin RegIIIγ Promotes the Spatial Segregation of Microbiota and Host in the Intestine
Innate immune signaling and antimicrobial peptide activity maintain separation of the microbiota and intestinal epithelium. The mammalian intestine is home to ~100 trillion bacteria that perform important metabolic functions for their hosts. The proximity of vast numbers of bacteria to host intestinal tissues raises the question of how symbiotic host-bacterial relationships are maintained without eliciting potentially harmful immune responses. Here, we show that RegIIIγ, a secreted antibacterial lectin, is essential for maintaining a ~50-micrometer zone that physically separates the microbiota from the small intestinal epithelial surface. Loss of host-bacterial segregation in RegIIIγ−/− mice was coupled to increased bacterial colonization of the intestinal epithelial surface and enhanced activation of intestinal adaptive immune responses by the microbiota. Together, our findings reveal that RegIIIγ is a fundamental immune mechanism that promotes host-bacterial mutualism by regulating the spatial relationships between microbiota and host.
44647875
Impaired gut barrier function in malnourished patients
The gastrointestinal tract is essential to host defence, acting as a barrier to absorption and translocation of gut antigens, including bacteria. In experimental models, protein malnutrition is permissive to gut barrier failure and endogenous infection. A clinical correlate has not been described. Intestinal morphology and barrier function to food protein antigens was studied in malnourished patients. Thirty‐five individuals were evaluated, 20 malnourished patients and 15 well nourished hospital controls. Morphology was assessed from endoscopic biopsies of the second part of the duodenum, and serum immunoglobulin (Ig) G antibodies to gliadin and β‐lactoglobulin were measured. No antibody to food proteins was evident in the control group. In contrast, serum IgG antibodies to at least one antigen were present in 15 malnourished patients and to both antigens in ten (P < 0.0001 versus controls). Severely malnourished patients were more likely to have both antibodies present than those with mild or moderate malnutrition (P < 0.05). Antibody‐positive malnourished patients had significantly better nutritional status than antibody‐negative patients with malnutrition (P < 0.05). In no group of patients was there morphological evidence of abnormal mucosa or an immunological infiltrate. Gut barrier function is compromised in malnourished patients which suggests a mechanism that may facilitate gut‐derived infection and sepsis.
22998797
Gut barrier function in malnourished patients
Background—The integrity of the gastrointestinal mucosa is a key element in preventing systemic absorption of enteric toxins and bacteria. In the critically ill, breakdown of gut barrier function may fuel sepsis. Malnourished patients have an increased risk of postoperative sepsis; however, the effects of malnutrition on intestinal barrier function in man are unknown. Aims—To quantify intestinal barrier function, endotoxin exposure, and the acute phase cytokine response in malnourished patients. Patients—Malnourished and well nourished hospitalised patients. Methods—Gastrointestinal permeability was measured in malnourished patients and well nourished controls using the lactulose:mannitol test. Endoscopic biopsy specimens were stained and morphological and immunohistochemical features graded. The polymerase chain reaction was used to determine mucosal cytokine expression. The immunoglobulin G antibody response to endotoxin and serum interleukin 6 were measured by enzyme linked immunosorbent assay. Results—There was a significant increase in intestinal permeability in the malnourished patients in association with phenotypic and molecular evidence of activation of lamina propria mononuclear cells and enterocytes, and a heightened acute phase response. Conclusions—Intestinal barrier function is significantly compromised in malnourished patients, but the clinical significance is unclear.
45502062
Contribution of enteric infection, altered intestinal barrier function, and maternal malnutrition to infant malnutrition in Bangladesh.
BACKGROUND
Malnourished children are at increased risk for death due to diarrhea. Our goal was to determine the contribution of specific enteric infections to malnutrition-associated diarrhea and to determine the role of enteric infections in the development of malnutrition.


METHODS
Children from an urban slum in Bangladesh were followed for the first year of life by every-other-day home visits. Enteropathogens were identified in diarrheal and monthly surveillance stools; intestinal barrier function was measured by serum endocab antibodies; and nutritional status was measured by anthropometry.


RESULTS
Diarrhea occurred 4.69 ± 0.19 times per child per year, with the most common infections caused by enteric protozoa (amebiasis, cryptosporidiosis, and giardiasis), rotavirus, astrovirus, and enterotoxigenic Escherichia coli (ETEC). Malnutrition was present in 16.3% of children at birth and 42.4% at 12 months of age. Children malnourished at birth had increased Entamoeba histolytica, Cryptosporidium, and ETEC infections and more severe diarrhea. Children who became malnourished by 12 months of age were more likely to have prolonged diarrhea, intestinal barrier dysfunction, a mother without education, and low family expenditure.


CONCLUSIONS
Prospective observation of infants in an urban slum demonstrated that diarrheal diseases were associated with the development of malnutrition that was in turn linked to intestinal barrier disruption and that diarrhea was more severe in already malnourished children. The enteric protozoa were unexpectedly important causes of diarrhea in this setting. This study demonstrates the complex interrelationship of malnutrition and diarrhea in infants in low-income settings and points to the potential for infectious disease interventions in the prevention and treatment of malnutrition.
22937137
The gut as a portal of entry for bacteremia. Role of protein malnutrition.
The current studies were performed to determine the influence of malnutrition alone or in combination with endotoxemia in promoting bacterial translocation from the gastrointestinal tract. Bacterial translocation did not occur in control, starved (up to 72 hours), or protein-malnourished (up to 21 days) mice not receiving endotoxin. Bacterial translocation to the mesenteric lymph nodes (MLNs) occurred in 80% of control mice 24 hours after receiving endotoxin (p less than 0.01). However, the combination of malnutrition plus endotoxin was associated with a higher incidence of translocation to the systemic organs (p less than 0.01), and higher numbers of bacteria per organ (p less than 0.01), than was seen in normally nourished mice receiving endotoxin. Additionally, mice that were protein malnourished were more susceptible to the lethal effects of endotoxin than were control animals, and the mortality rate was directly related to the degree of malnutrition (R2 = 0.93) (p less than 0.05). Histologically, endotoxin in combination with protein malnutrition resulted in mechanical damage to the gut mucosal barrier to bacteria. Thus, in the mice that were protein malnourished the spread of bacteria from the gut could not be controlled nor could translocated bacteria be cleared as well as normally nourished mice receiving endotoxin. These results support the concept that under certain circumstances the gut may serve as a clinically important portal of entry for bacteria.
46775621
Apolipoprotein E knockout mice have accentuated malnutrition with mucosal disruption and blunted insulin-like growth factor I responses to refeeding.
Apolipoprotein E (apoE) is synthesized mainly in the liver and in the brain and is critical for cholesterol metabolism and recovery from brain injury. However, although apoE mRNA increases at birth, during suckling, and after fasting in rat liver, little is known about its role in early postnatal development. Using an established postnatal malnutrition model and apoE knock-out (ko) mice, we examined the role of apoE in intestinal adaptation responses to early postnatal malnutrition. Wild-type and apoE-ko mice were separated from their lactating dams for defined periods each day (4 hours on day 1, 8 hours on day 2, and 12 hours thereafter). We found significant growth deficits, as measured by weight gain or tail length, in the apoE-ko mice submitted to a malnutrition challenge, as compared with malnourished wild type, especially during the second week of postnatal development (P < .05). In addition, apoE-ko animals failed to show growth catch-up after refeeding, compared with wild-type malnourished controls. Furthermore, we found shorter crypts and reduced villus height and area in the apoE-ko malnourished mice, compared with controls, after refeeding. Insulinlike growth factor 1 expression was also blunted in the ileum in apoE-ko mice after refeeding, compared with wild-type controls, which exhibited full insulinlike growth factor 1 expression along the intestinal crypts, villi, and in the muscular layer. Taken together, these findings suggest the importance of apoE in coping with a malnutrition challenge and during the intestinal adaptation after refeeding.
22143671
Malnutrition as an enteric infectious disease with long-term effects on child development.
Malnutrition is a major contributor to mortality and is increasingly recognized as a cause of potentially lifelong functional disability. Yet, a rate-limiting step in achieving normal nutrition may be impaired absorptive function due to multiple repeated enteric infections. This is especially problematic in children whose diets are marginal. In malnourished individuals, the infections are even more devastating. This review documents the evidence that intestinal infections lead to malnutrition and that malnutrition worsens intestinal infections. The clinical data presented here derive largely from long-term cohort studies that are supported by controlled animal studies. Also reviewed are the mechanisms by which enteric infections lead to undernutrition and by which malnutrition worsens enteric infections, with implications for potential novel interventions. Further intervention studies are needed to document the relevance of these mechanisms and, most importantly, to interrupt the vicious diarrhea-malnutrition cycle so children may develop their full potential.
20834720
Cd1d-dependent regulation of bacterial colonization in the intestine of mice.
The accumulation of certain species of bacteria in the intestine is involved in both tissue homeostasis and immune-mediated pathologies. The host mechanisms involved in controlling intestinal colonization with commensal bacteria are poorly understood. We observed that under specific pathogen-free or germ-free conditions, intragastric administration of Pseudomonas aeruginosa, E. coli, Staphylococcus aureus, or Lactobacillus gasseri resulted in increased colonization of the small intestine and bacterial translocation in mice lacking Cd1d, an MHC class I-like molecule, compared with WT mice. In contrast, activation of Cd1d-restricted T cells (NKT cells) with alpha-galactosylceramide caused diminished intestinal colonization with the same bacterial strains. We also found prominent differences in the composition of intestinal microbiota, including increased adherent bacteria, in Cd1d-/- mice in comparison to WT mice under specific pathogen-free conditions. Germ-free Cd1d-/- mice exhibited a defect in Paneth cell granule ultrastructure and ability to degranulate after bacterial colonization. In vitro, NKT cells were shown to induce the release of lysozyme from intestinal crypts. Together, these data support a role for Cd1d in regulating intestinal colonization through mechanisms that include the control of Paneth cell function.
26452635
Level of activation of the unfolded protein response correlates with Paneth cell apoptosis in human small intestine exposed to ischemia/reperfusion.
BACKGROUND & AIMS
In the intestine, Paneth cells participate in the innate immune response. Their highly secretory function makes them susceptible to environmental conditions that cause endoplasmic reticulum (ER) stress. We investigated whether intestinal ischemia/reperfusion (I/R) induces ER stress, thereby activating the unfolded protein response (UPR), and whether excessive UPR activation affects Paneth cells. In addition, we investigated the consequences of Paneth cell compromise during physical barrier damage.


METHODS
Jejunal I/R was studied using a human experimental model (n = 30 patients). Activation of the UPR was assessed using immunofluorescence for binding protein and quantitative polymerase chain reaction analyses for C/EBP homologous protein (CHOP), growth arrest and DNA-damage inducible protein 34 (GADD34), and X-box binding protein 1 (XBP1) splicing. Paneth cell apoptosis was assessed by double staining for lysozyme and M30. Male Sprague-Dawley rats underwent either intestinal I/R to investigate UPR activation and Paneth cell apoptosis, or hemorrhagic shock with or without intraperitoneal administration of dithizone, to study consequences of Paneth cell compromise during physical intestinal damage. In these animals, bacterial translocation and circulating tumor necrosis factor-α and interleukin-6 levels were assessed.


RESULTS
In jejunum samples from humans and rats, I/R activated the UPR and resulted in Paneth cell apoptosis. Apoptotic Paneth cells showed signs of ER stress, and Paneth cell apoptosis correlated with the extent of ER stress. Apoptotic Paneth cells were shed into the crypt lumen, significantly lowering their numbers. In rats, Paneth cell compromise increased bacterial translocation and inflammation during physical intestinal damage.


CONCLUSIONS
ER stress-induced Paneth cell apoptosis contributes to intestinal I/R-induced bacterial translocation and systemic inflammation.
10820430
A Novel Role for Defensins in Intestinal Homeostasis: Regulation of IL-1β Secretion1
Impaired expression of α-defensin antimicrobial peptides and overproduction of the proinflammatory cytokine IL-1β have been associated with inflammatory bowel disease. In this study, we examine the interactions between α-defensins and IL-1β and the role of defensin deficiency in the pathogenesis of inflammatory bowel disease. It was found that matrix metalloproteinase-7-deficient (MMP-7−/−) mice, which produce procryptdins but not mature cryptdins (α-defensins) in the intestine, were more susceptible to dextran sulfate sodium-induced colitis. Furthermore, both baseline and dextran sulfate sodium-induced IL-1β production in the intestine were significantly up-regulated in MMP-7−/− mice compared with that in control C57BL/6 mice. To elucidate the molecular mechanism for the increased IL-1β production in defensin deficiency in vivo, we evaluated the effect of defensins on IL-1β posttranslational processing and release. It was found that α-defensins, including mouse Paneth cell defensins cryptdin-3 and cryptdin-4, human neutrophil defensin HNP-1, and human Paneth cell defensin HD-5, blocked the release of IL-1β from LPS-activated monocytes, whereas TNF-α expression and release were not affected. Unlike α-defensins, human β-defensins and mouse procryptdins do not have any effect on IL-1β processing and release. Thus, α-defensins may play an important role in intestinal homeostasis by controlling the production of IL-1β.
3214191
Mechanism of IL-1β-Induced Increase in Intestinal Epithelial Tight Junction Permeability1
The IL-1β-induced increase in intestinal epithelial tight junction (TJ) permeability has been postulated to be an important mechanism contributing to intestinal inflammation of Crohn’s disease and other inflammatory conditions of the gut. The intracellular and molecular mechanisms that mediate the IL-1β-induced increase in intestinal TJ permeability remain unclear. The purpose of this study was to elucidate the mechanisms that mediate the IL-1β-induced increase in intestinal TJ permeability. Specifically, the role of myosin L chain kinase (MLCK) was investigated. IL-1β caused a progressive increase in MLCK protein expression. The time course of IL-1β-induced increase in MLCK level correlated linearly with increase in Caco-2 TJ permeability. Inhibition of the IL-1β-induced increase in MLCK protein expression prevented the increase in Caco-2 TJ permeability. Inhibition of the IL-1β-induced increase in MLCK activity also prevented the increase in Caco-2 TJ permeability. Additionally, knock-down of MLCK protein expression by small interference RNA prevented the IL-1β-induced increase in Caco-2 TJ permeability. The IL-1β-induced increase in MLCK protein expression was preceded by an increase in MLCK mRNA expression. The IL-1β-induced increase in MLCK mRNA transcription and subsequent increase in MLCK protein expression and Caco-2 TJ permeability was mediated by activation of NF-κB. In conclusion, our data indicate that the IL-1β increase in Caco-2 TJ permeability was mediated by an increase in MLCK expression and activity. Our findings also indicate that the IL-1β-induced increase in MLCK protein expression and Caco-2 TJ permeability was mediated by an NF-κB-dependent increase in MLCK gene transcription.
1565580
IL-1β Causes an Increase in Intestinal Epithelial Tight Junction Permeability1
IL-1β is a prototypical proinflammatory cytokine that plays a central role in the intestinal inflammation amplification cascade. Recent studies have indicated that a TNF-α- and IFN-γ-induced increase in intestinal epithelial paracellular permeability may be an important mechanism contributing to intestinal inflammation. Despite its central role in promoting intestinal inflammation, the role of IL-1β on intestinal epithelial tight junction (TJ) barrier function remains unclear. The major aims of this study were to determine the effect of IL-1β on intestinal epithelial TJ permeability and to elucidate the mechanisms involved in this process, using a well-established in vitro intestinal epithelial model system consisting of filter-grown Caco-2 intestinal epithelial monolayers. IL-1β (0–100 ng/ml) produced a concentration- and time-dependent decrease in Caco-2 transepithelial resistance. Conversely, IL-1β caused a progressive time-dependent increase in transepithelial permeability to paracellular marker inulin. IL-1β-induced increase in Caco-2 TJ permeability was accompanied by a rapid activation of NF-κB. NF-κB inhibitors, pyrrolidine dithiocarbamate and curcumin, prevented the IL-1β-induced increase in Caco-2 TJ permeability. To further confirm the role of NF-κB in the IL-1β-induced increase in Caco-2 TJ permeability, NF-κB p65 expression was silenced by small interfering RNA transfection. NF-κB p65 depletion completely inhibited the IL-1β-induced increase in Caco-2 TJ permeability. IL-1β did not induce apoptosis in the Caco-2 cell. In conclusion, our findings show for the first time that IL-1β at physiologically relevant concentrations causes an increase in intestinal epithelial TJ permeability. The IL-1β-induced increase in Caco-2 TJ permeability was mediated in part by the activation of NF-κB pathways but not apoptosis.
13116577
Growth and chronic disease: findings in the Helsinki Birth Cohort
There is now clear evidence that the pace and pathway of early growth is a major risk factor for the development of a group of chronic diseases that include coronary heart disease, stroke, type 2 diabetes and hypertension. This has led to a new ‘developmental’ model for these disorders. The so-called ‘fetal origins hypothesis’ proposes that the disorders originate through developmental plasticity, whereby malnutrition during fetal life, infancy and early childhood permanently change the structure and function of the body, a phenomenon known as ‘programming’. This paper reviews recent findings in the Helsinki Birth Cohort, which comprises 13 345 men and women born in the city during 1934–1944. There is also an older cohort comprising 7086 people born during 1924–1933. We review the paths of pre- and postnatal growth that lead to later disease. Children who later develop coronary heart disease and type 2 diabetes grow slowly during fetal life and infancy but thereafter increase their body mass indices rapidly. Those who later develop stroke grow slowly in fetal life, infancy and during childhood. We also review how the growth of girls during infancy, childhood and at puberty influences chronic disease in the next generation.
23028832
Enteric glia express proteolipid protein 1 and are a transcriptionally unique population of glia in the mammalian nervous system
In the enteric nervous system (ENS), glia outnumber neurons by 4‐fold and form an extensive network throughout the gastrointestinal tract. Growing evidence for the essential role of enteric glia in bowel function makes it imperative to understand better their molecular marker expression and how they relate to glia in the rest of the nervous system. We analyzed expression of markers of astrocytes and oligodendrocytes in the ENS and found, unexpectedly, that proteolipid protein 1 (PLP1) is specifically expressed by glia in adult mouse intestine. PLP1 and S100β are the markers most widely expressed by enteric glia, while glial fibrillary acidic protein expression is more restricted. Marker expression in addition to cellular location and morphology distinguishes a specific subpopulation of intramuscular enteric glia, suggesting that a combinatorial code of molecular markers can be used to identify distinct subtypes. To assess the similarity between enteric and extraenteric glia, we performed RNA sequencing analysis on PLP1‐expressing cells in the mouse intestine and compared their gene expression pattern to that of other types of glia. This analysis shows that enteric glia are transcriptionally unique and distinct from other cell types in the nervous system. Enteric glia express many genes characteristic of the myelinating glia, Schwann cells and oligodendrocytes, although there is no evidence of myelination in the murine ENS. GLIA 2015;63:2040–2057
17561194
Glial cells in the mouse enteric nervous system can undergo neurogenesis in response to injury.
The enteric nervous system (ENS) in mammals forms from neural crest cells during embryogenesis and early postnatal life. Nevertheless, multipotent progenitors of the ENS can be identified in the adult intestine using clonal cultures and in vivo transplantation assays. The identity of these neurogenic precursors in the adult gut and their relationship to the embryonic progenitors of the ENS are currently unknown. Using genetic fate mapping, we here demonstrate that mouse neural crest cells marked by SRY box-containing gene 10 (Sox10) generate the neuronal and glial lineages of enteric ganglia. Most neurons originated from progenitors residing in the gut during mid-gestation. Afterward, enteric neurogenesis was reduced, and it ceased between 1 and 3 months of postnatal life. Sox10-expressing cells present in the myenteric plexus of adult mice expressed glial markers, and we found no evidence that these cells participated in neurogenesis under steady-state conditions. However, they retained neurogenic potential, as they were capable of generating neurons with characteristics of enteric neurons in culture. Furthermore, enteric glia gave rise to neurons in vivo in response to chemical injury to the enteric ganglia. Our results indicate that despite the absence of constitutive neurogenesis in the adult gut, enteric glia maintain limited neurogenic potential, which can be activated by tissue dissociation or injury.
41464640
Obesity in pregnancy stimulates macrophage accumulation and inflammation in the placenta.
Abstract Obesity and pregnancy are associated with a combination of insulin resistance and inflammatory changes which exacerbate in combination. Based on the similarity between the inflammatory transcriptomes of adipose tissue and placenta, we hypothesized that the placenta develops exaggerated inflammation in response to obesity. The aim of this study was to characterize placental inflammatory mediators and macrophage accumulation in relation to peripheral inflammation in obesity. Placental macrophages and maternal peripheral blood mononuclear cells (PBMC) from 20 obese and 15 lean women were functionally and phenotypically characterized using immunohistochemistry, flow cytometry and expression for macrophage markers and inflammatory cytokines. The number of resident CD68+ and CD14+ cells was increased 2–3 fold in the placenta of obese as compared to lean women. The macrophage population was characterized by a marked phenotypic heterogeneity with complex subsets of CD14+, CD68+ and CD11b+ (mac-1) cells and by an increased expression of the pro-inflammatory cytokines IL-1, TNF-alpha, IL-6. Placental inflammation was associated with an activation of PBMC gene expression with an increase in the monocyte differentiation and maturation markers CD14 and CD68 in maternal but not fetal PBMC. The inflammatory changes were associated with higher plasma concentrations of C-reactive protein and IL-6 in obese compared to lean women. In conclusion, the chronic inflammation state of pre-gravid obesity is extending to in utero life with accumulation of a heterogeneous macrophage population and pro-inflammatory mediators in the placenta. The resulting inflammatory milieu in which the fetus develops may have critical consequences for short and long term programming of obesity.
10644802
Enduring consequences of maternal obesity for brain inflammation and behavior of offspring
Obesity is well characterized as a systemic inflammatory condition, and is also associated with cognitive disruption, suggesting a link between the two. We assessed whether peripheral inflammation in maternal obesity may be transferred to the offspring brain, in particular, the hippocampus, and thereby result in cognitive dysfunction. Rat dams were fed a high‐saturated‐fat diet (SFD), a high‐trans‐fat diet (TFD), or a low‐fat diet (LFD) for 4 wk prior to mating, and remained on the diet throughout pregnancy and lactation. SFD/TFD exposure significantly increased body weight in both dams and pups compared to controls. Microglial activation markers were increased in the hippocampus of SFD/TFD pups at birth. At weaning and in adulthood, proinflammatory cytokine expression was strikingly increased in the periphery and hippocampus following a bacterial challenge [lipopolysaccharide (LPS)] in the SFD/TFD groups compared to controls. Microglial activation within the hippocampus was also increased basally in SFD rats, suggesting a chronic priming of the cells. Finally, there were marked changes in anxiety and spatial learning in SFD/TFD groups. These effects were all observed in adulthood, even after the pups were placed on standard chow at weaning, suggesting these outcomes were programmed early in life.—Bilbo, S. D., Tsang, V. Enduring consequences of maternal obesity for brain inflammation and behavior of offspring. FASEB J. 24, 2104–2115 (2010). www.fasebj.org
31226981
Placental structure and inflammation in pregnancies associated with obesity.
BACKGROUND
Pre-gravid obesity is associated with increased morbidity and mortality for both mother and offspring. Recent studies have demonstrated a heightened inflammatory response both systemically and locally within the adipose and placental tissue in women with pre-gravid obesity, which may play a role in mediating the adverse pregnancy outcomes. The aim of this study was to characterise the maternal and placental inflammatory status and investigate associated changes in placental structure in obese women.


METHODS
The pro-inflammatory status of a cohort of 47 non-obese (BMI 20-25 kg/m(2)) and 33 obese (≥30 kg/m(2)) women was characterised by measuring maternal circulating levels and placental gene expression of pro-inflammatory cytokines, and quantifying immune cell populations within the placenta. The effect of pre-gravid obesity on placental structure was investigated by examining placental maturity, vessel density, the formation of syncytial knots and sprouts, and the degree of fibrin deposition, chorangiosis and muscularisation of vessel walls.


RESULTS
Maternal obesity was associated with significantly greater IL-1β (p < 0.05), IL-8 (p < 0.05), MCP-1 (p < 0.001) and CXCR2 (p < 0.05) mRNA expression within the placenta and higher circulating maternal levels of IL-6 (3.30 ± 0.38 vs. 1.77 ± 0.15 pg/ml) (p < 0.001) compared with non-obese women. There were no differences in the number of CD14(+), CD68(+) cells or neutrophils within the placental villi of non-obese and obese women. However there were significantly higher numbers of neutrophils within the interstitial space (p < 0.05). Greater muscularity of placental vessel walls was associated with maternal obesity (p = 0.03), however no other associated structural changes were observed.


CONCLUSIONS
Our findings show that although pre-gravid obesity was associated with greater expression of placental pro-inflammatory cytokines and higher circulating IL-6 in pregnancy, there were no major differences in immune cell populations within the placental villi and only a greater degree of muscularity in the vessel walls.
25927516
A High-Fat/High-Cholesterol Diet Inhibits Growth of Fetal Hippocampal Transplants via Increased Inflammation
A diet containing high levels of saturated fat and cholesterol is detrimental to many aspects of health and is known to lead to obesity, metabolic syndrome, heart disease, diabetes, and cancer. However, the effects of a diet rich in saturated fat and cholesterol on the brain are not currently well understood. In order to determine direct effects of a high saturated fat and cholesterol diet upon fetal hippocampal tissue, we transplanted hippocampal grafts from embryonic day 18 rats to the anterior eye chamber of 16-month-old host animals that were fed either a normal rat chow diet or a 10% hydrogenated coconut oil + 2% cholesterol diet (HFHC diet) for 8 weeks. One eye per rat received topical application of an IL-1 receptor antagonist (IL-1Ra, Kineret®) and the other served as a saline control. Results revealed that the HFHC diet led to a marked reduction in hippocampal transplant growth, and detrimental effects of the diet were alleviated by the IL-1 receptor antagonist IL-1Ra. Graft morphology demonstrated that the HFHC diet reduced organotypical development of the hippocampal neuronal cell layers, which was also alleviated by IL-1Ra. Finally, grafts were evaluated with markers for glucose transporter expression, astrocytes, and activated microglia. Our results demonstrate significant effects of the HFHC diet on hippocampal morphology, including elevated microglial activation and reduced neuronal development. IL-1Ra largely blocked the detrimental effects of this diet, suggesting a potential use for this agent in neurological disorders involving neuroinflammation.
206758114
Toll-Like Receptor Stimulation Induces Nondefensin Protein Expression and Reverses Antibiotic-Induced Gut Defense Impairment
ABSTRACT Prior antibiotic exposure is associated with increased mortality in Gram-negative bacteria-induced sepsis. However, how antibiotic-mediated changes of commensal bacteria promote the spread of enteric pathogenic bacteria in patients remains unclear. In this study, the effects of systemic antibiotic treatment with or without Toll-like receptor (TLR) stimulation on bacterium-killing activity, antibacterial protein expression in the intestinal mucosa, and bacterial translocation were examined in mice receiving antibiotics with or without oral supplementation of dead Escherichia coli or Staphylococcus aureus. We developed a systemic ampicillin, vancomycin, and metronidazole treatment protocol to simulate the clinical use of antibiotics. Antibiotic treatment decreased the total number of bacteria, including aerobic bacteria belonging to the family Enterobacteriaceae and the genus Enterococcus as well as organisms of the anaerobic genera Lactococcus and Bifidobacterium in the intestinal mucosa and lumen. Antibiotic treatment significantly decreased the bacterium-killing activity of the intestinal mucosa and the expression of non-defensin-family proteins, such as RegIIIβ, RegIIIγ, C-reactive protein-ductin, and RELMβ, but not the defensin-family proteins, and increased Klebsiella pneumoniae translocation. TLR stimulation after antibiotic treatment increased NF-κB DNA binding activity, nondefensin protein expression, and bacterium-killing activity in the intestinal mucosa and decreased K. pneumoniae translocation. Moreover, germfree mice showed a significant decrease in nondefensin proteins as well as intestinal defense against pathogen translocation. Since TLR stimulation induced NF-κB DNA binding activity, TLR4 expression, and mucosal bacterium-killing activity in germfree mice, we conclude that the commensal microflora is critical in maintaining intestinal nondefensin protein expression and the intestinal barrier. In turn, we suggest that TLR stimulation induces nondefensin protein expression and reverses antibiotic-induced gut defense impairment.
17066985
Release of Luminal Exosomes Contributes to TLR4-Mediated Epithelial Antimicrobial Defense
Exosomes are membranous nanovesicles released by most cell types from multi-vesicular endosomes. They are speculated to transfer molecules to neighboring or distant cells and modulate many physiological and pathological procedures. Exosomes released from the gastrointestinal epithelium to the basolateral side have been implicated in antigen presentation. Here, we report that luminal release of exosomes from the biliary and intestinal epithelium is increased following infection by the protozoan parasite Cryptosporidium parvum. Release of exosomes involves activation of TLR4/IKK2 signaling through promoting the SNAP23-associated vesicular exocytotic process. Downregulation of let-7 family miRNAs by activation of TLR4 signaling increases SNAP23 expression, coordinating exosome release in response to C. parvum infection. Intriguingly, exosomes carry antimicrobial peptides of epithelial cell origin, including cathelicidin-37 and beta-defensin 2. Activation of TLR4 signaling enhances exosomal shuttle of epithelial antimicrobial peptides. Exposure of C. parvum sporozoites to released exosomes decreases their viability and infectivity both in vitro and ex vivo. Direct binding to the C. parvum sporozoite surface is required for the anti-C. parvum activity of released exosomes. Biliary epithelial cells also increase exosomal release and display exosome-associated anti-C. parvum activity following LPS stimulation. Our data indicate that TLR4 signaling regulates luminal exosome release and shuttling of antimicrobial peptides from the gastrointestinal epithelium, revealing a new arm of mucosal immunity relevant to antimicrobial defense.
13090401
Antimicrobial peptide elicitors: new hope for the post-antibiotic era.
Antimicrobial peptides or host defense peptides are fundamental components of human innate immunity. Recent and growing evidence suggests they have a role in a broad range of diseases, including cancer, allergies and susceptibility to infection, including HIV/AIDS. Antimicrobial peptide elicitors (APEs) are physical, biological or chemical agents that boost human antimicrobial peptide expression. The current knowledge of APEs and their potential use in the treatment of human infectious diseases are reviewed, and a classification system for APEs is proposed. The efficient use of APEs in clinical practice could mark the beginning of the urgently needed post-antibiotic era, but further trials assessing their efficacy and safety are required.
34659367
Inflammation and disruption of the mucosal architecture in claudin-7-deficient mice.
BACKGROUND & AIMS
Integrity of the intestinal epithelium is required for nutrition absorption and defense against pathogens. Claudins are cell adhesion molecules that localize at tight junctions (TJs); many are expressed in the intestinal tract, but little is known about their functions. Claudin-7 is unique in that it has a stronger basolateral membrane distribution than other claudins, which localize primarily to apical TJs in the intestinal epithelium. We investigated the basolateral functions of claudin-7 and assessed the effects of disruption of Cldn7 in intestines of mice.


METHODS
We generated Cldn7(-/-) mice and examined their intestines by histology, molecular and cellular biology, and biochemistry approaches. We performed gene silencing experiments in epithelial cell lines using small interfering RNAs (siRNAs).


RESULTS
The Cldn7(-/-) mice had severe intestinal defects that included mucosal ulcerations, epithelial cell sloughing, and inflammation. Intestines of Cldn7(-/-) mice produced significantly higher levels of cytokines, the nuclear factor κB p65 subunit, and cyclooxygenase 2; they also up-regulated expression of matrix metalloproteinases (MMPs)-3 and -7. siRNA in epithelial cell lines showed that the increased expression of MMP-3 resulted directly from claudin-7 depletion, whereas that of MMP-7 resulted from inflammation. Electron microscopy analysis showed that intestines of Cldn7(-/-) mice had intercellular gaps below TJs and cell matrix loosening. Deletion of Cldn7 reduced expression and altered localization of the integrin α2 subunit in addition to disrupting formation of complexes of claudin-7, integrin α2, and claudin-1 that normally form in epithelial basolateral compartments of intestines.


CONCLUSIONS
In mice, claudin-7 has non-TJ functions, including maintenance of epithelial cell-matrix interactions and intestinal homeostasis.
14568573
SOX9 is an intestine crypt transcription factor, is regulated by the Wnt pathway, and represses the CDX2 and MUC2 genes
TCF and SOX proteins belong to the high mobility group box transcription factor family. Whereas TCFs, the transcriptional effectors of the Wnt pathway, have been widely implicated in the development, homeostasis and disease of the intestine epithelium, little is known about the function of the SOX proteins in this tissue. Here, we identified SOX9 in a SOX expression screening in the mouse fetal intestine. We report that the SOX9 protein is expressed in the intestinal epithelium in a pattern characteristic of Wnt targets. We provide in vitro and in vivo evidence that a bipartite β-catenin/TCF4 transcription factor, the effector of the Wnt signaling pathway, is required for SOX9 expression in epithelial cells. Finally, in colon epithelium-derived cells, SOX9 transcriptionally represses the CDX2 and MUC2 genes, normally expressed in the mature villus cells of the intestinal epithelium, and may therefore contribute to the Wnt-dependent maintenance of a progenitor cell phenotype.
6868134
Distortions in Development of Intestinal Microbiota Associated with Late Onset Sepsis in Preterm Infants
Late onset sepsis (LOS) is a major contributor to neonatal morbidity and mortality, especially in premature infants. Distortions in the establishment of normal gut microbiota, commensal microbes that colonize the digestive tract, might increase the risk of LOS via disruption of the mucosal barrier with resultant translocation of luminal contents. Correlation of distortions of the intestinal microbiota with LOS is a necessary first step to design novel microbiota-based screening approaches that might lead to early interventions to prevent LOS in high risk infants. Using a case/control design nested in a cohort study of preterm infants, we analyzed stool samples that had been prospectively collected from ten preterm infants with LOS and from 18 matched controls. A 16S rRNA based approach was utilized to compare microbiota diversity and identify specific bacterial signatures that differed in their prevalence between cases and controls. Overall α-diversity (Chao1) was lower in cases two weeks before (p<0.05) but not one week before or at the time of diagnosis of LOS. Overall microbiota structure (Unifrac) appeared distinct in cases 2 weeks and 1 week before but not at diagnosis (p<0.05). Although we detected few operational taxonomic units (OTUs) unique or enriched in cases, we found many OTUs common in controls that were lacking in cases (p<0.01). Bifidobacteria counts were lower in cases at all time points. Our results support the hypothesis that a distortion in normal microbiota composition, and not an enrichment of potential pathogens, is associated with LOS in preterm infants.
23273485
Gut-origin sepsis: evolution of a concept.
The concept of bacterial translocation and gut-origin sepsis as a cause of systemic infectious complications and the multiple organ dysfunction syndrome (MODS) in surgical and ICU patients has emerged over the last several decades, although the exact clinical relevance of these phenomena continues to be debated. Thus, the goal of this review is to trace the evolution of gut-origin sepsis and gut-induced MODS and put these disorders and observations into clinical perspective. Additionally, the mechanisms leading to gut-derived complications are explored as well as therapeutic options to limit or prevent these complications. From this work, several major conclusions emerge. First, that bacterial translocation occurs clinically and is responsible for increased infectious complications in patients undergoing major abdominal surgery. However, the phenomenon of bacterial translocation is not sufficient to explain the development of MODS in ICU patients. Instead, the development of MODS in these high-risk patients is likely due to gut injury and the systemic spread of non-microbial, tissue-injurious factors that reach the systemic circulation via the intestinal lymphatics. These observations have resulted in the gut-lymph hypothesis of MODS.
36175417
Ontogenetic development of intestinal nutrient transporters.
sharing the same DNA, express different subsets of those genes at a given time, and why each cell expresses different genes at different times. This problem is conspicuous for the ver­ tebrate gastrointestinal tract, which undergoes two dramatic developmental transitions associated with changing functional demands. At the first and more abrupt transition, coinciding with birth in mammals and hatching in birds, the gut assumes from the yolk sac or placenta the responsibility for extracting nutrients. At the second transition, coinciding with weaning in mammals and metamorphosis in amphibia, many species experience a marked change in diet. Ontogenetic development has been intensively studied for many gut func­ tions, such as secretion of enzymes and gastric acid (30-32, 41, 42). Less information has been available for intestinal nutrient transporters, but studies of their development are now proliferating. Our review begins by summariz­ ing patterns of prenatal and postnatal development for transporters of sugars, amino acids, peptides, bile salts, and vitamins. We then consider de­ velopmental changes in regionalization of transport along two axes: the length of the intestine, and the crypt/villus axis of the intestinal mucosa. After
11090681
Intestinal Permeability and Carrier-Mediated Monosaccharide Absorption in Preterm Neonates during the Early Postnatal Period
Immaturity of intestinal epithelial barrier function and absorptive capacity may play a role in the pathophysiology of intestinal complications in preterm neonates during the early postnatal period. We determined the intestinal permeability and carrier-mediated absorption of monosaccharides in preterm neonates during the first 2 wk after birth. Fifty-nine preterm neonates born between 25 and 32 wk gestation were included within 24 h of birth. Neonates received exclusively parenteral nutrition during the first 7 d after birth; enteral feeding was initiated at d 8. An intestinal permeability-absorption test was performed at 1, 4, 7, and 14 d after birth. The lactulose-to-rhamnose ratio was determined as a marker of intestinal permeability. Urinary excretion percentages of d-xylose and 3-O-methyl-d-glucose were determined as markers of passive and active carrier-mediated monosaccharide absorption, respectively. Intestinal permeability transiently increased between d 1 and 7 in all neonates (p < 0.05). Carrier-mediated monosaccharide absorption increased between d 1 and 14 in neonates of 28–30 wk (p < 0.05) to the level observed in the neonates of 30–32 wk gestation. In neonates <28 wk, intestinal permeability at d 7 was higher (p < 0.05) and carrier-mediated monosaccharide absorption at d 14 was lower (p < 0.01) as compared with neonates ≥28 wk. The barrier function of the intestinal epithelium transiently decreases during the first week after birth in preterm neonates who are not enterally fed. Diminished barrier function and low monosaccharide absorptive capacity, particularly in neonates <28 wk, may predispose these patients to the development of intestinal complications during the early postnatal period.
7066465
The absorption of vitamin A in prematurely born infants with experience in the use of absorbable vitamin A in the prophylaxis of retrolental fibroplasia.
Forty-two premature infants were tested for vitamin A absorption after the oral ingestion of 0.5 cc. (35,000 U.S.P. units) of percomorph liver oil. Only three (7%) showed good absorption levels. The mean absorption level found from three to five hours after the test dose was 16 units of vitamin A. Forty-one were tested for vitamin A absorption after the oral ingestion of either 2 cc. or 3 cc. (16,000-24,000 U.S.P. units) of vitamin A in a vehicle of either alcohol or propylene glycol. Of these 37 (90%) showed good absorption levels. The mean absorption level found from three to five hours after the test dose was 85 units of vitamin A. Retrolental fibroplasia could not be prevented from developing in a certain number of premature infants9 eyes by the daily oral administration of 5000 U.S.P. of vitamin A in an absorbable water soluble form. Even the addition of 20,000 U.S.P. units of vitamin A in oil by intramuscular injection failed to prevent the development of bilateral retrolental fibroplasia in one infant. If vitamin D follows the same laws of absorption as does vitamin A, the provision of both A and D in a readily absorbable form should be of great practical advantage to the prematurely born infant.
21398608
Nutritional modulation of the gut microbiota and immune system in preterm neonates susceptible to necrotizing enterocolitis.
The gastrointestinal inflammatory disorder, necrotizing enterocolitis (NEC), is among the most serious diseases for preterm neonates. Nutritional, microbiological and immunological dysfunctions all play a role in disease progression but the relationship among these determinants is not understood. The preterm gut is very sensitive to enteral feeding which may either promote gut adaptation and health, or induce gut dysfunction, bacterial overgrowth and inflammation. Uncontrolled inflammatory reactions may be initiated by maldigestion and impaired mucosal protection, leading to bacterial overgrowth and excessive nutrient fermentation. Tumor necrosis factor alpha, toll-like receptors and heat-shock proteins are identified among the immunological components of the early mucosal dysfunction. It remains difficult, however, to distinguish the early initiators of NEC from the later consequences of the disease pathology. To elucidate the mechanisms and identify clinical interventions, animal models showing spontaneous NEC development after preterm birth coupled with different forms of feeding may help. In this review, we summarize the literature and some recent results from studies on preterm pigs on the nutritional, microbial and immunological interactions during the early feeding-induced mucosal dysfunction and later NEC development. We show that introduction of suboptimal enteral formula diets, coupled with parenteral nutrition, predispose to disease, while advancing amounts of mother's milk from birth (particularly colostrum) protects against disease. Hence, the transition from parenteral to enteral nutrition shortly after birth plays a pivotal role to secure gut growth, digestive maturation and an appropriate response to bacterial colonization in the sensitive gut of preterm neonates.
8768571
Necrotizing enterocolitis risk: state of the science.
Necrotizing enterocolitis (NEC) is the most common cause of gastrointestinal-related morbidity and mortality in the neonatal intensive care unit (NICU). Its onset is sudden and the smallest, most premature infants are the most vulnerable. Necrotizing enterocolitis is a costly disease, accounting for nearly 20% of NICU costs annually. Necrotizing enterocolitis survivors requiring surgery often stay in the NICU more than 90 days and are among those most likely to stay more than 6 months. Significant variations exist in the incidence across regions and units. Although the only consistent independent predictors for NEC remain prematurity and formula feeding, others exist that could increase risk when combined. Awareness of NEC risk factors and adopting practices to reduce NEC risk, including human milk feeding, the use of feeding guidelines, and probiotics, have been shown to reduce the incidence of NEC. The purpose of this review is to examine the state of the science on NEC risk factors and make recommendations for practice and research.
3455047
Necrotizing Enterocolitis in the Premature Infant: Neonatal Nursing Assessment, Disease Pathogenesis, and Clinical Presentation
Necrotizing enterocolitis (NEC) remains one of the most catastrophic comorbidities associated with prematurity. In spite of extensive research, the disease remains unsolved. The aims of this article are to present the current state of the science on the pathogenesis of NEC, summarize the clinical presentation and severity staging of the disease, and highlight the nursing assessments required for early identification of NEC and ongoing care for infants diagnosed with this gastrointestinal disease. The distributions of systemic and intestinal clinical signs that are most sensitive to nursing assessment and associated with Bell Staging Criteria are presented. These descriptive data are representative of 117 cases of NEC diagnosed in low-gestational-age infants (<29 weeks' gestation). The data highlight the clinical signs most commonly observed in infants with NEC and thus provide NICU nurses an evidence-based guide for assessment and care of infants with NEC.
24987933
Epidemiology of necrotizing enterocolitis – Part II: Risks and susceptibility of premature infants during the surfactant era: A regional study
Objectives:  We observed a reduced incidence of necrotizing enterocolitis (NEC) despite increased survival of extremely premature infants over the last two decades. A different susceptibility pattern to NEC according to gestation has been proposed. We aim to examine the influence of perinatal risk factors for NEC in infants less than 32 weeks gestation, in our region, in the post‐surfactant era.
11483055
Sex Differences in a Hypoxia Model of Preterm Brain Damage
Male sex is a well-established risk factor for poor neurodevelopmental outcome after premature birth. The mechanisms behind this sex-related difference are unknown. The damage associated with prematurity can be mimicked in rodents by prolonged exposure to sublethal postnatal hypoxia. This chronic hypoxia leads to anatomical changes in mice that strongly resemble the loss of volume, decreased myelination, and ventriculomegaly seen in preterm newborns. However, no sex differences have been previously noted in this rodent model. We hypothesized that sex comparisons in hypoxic mice would show sex-related differences in brain volume and white matter loss in response to the same degree of hypoxic insult. Mice were placed in chronic sublethal hypoxia from postnatal day 3–11. Cortical, hippocampal, and cerebellar volumes and myelination indices were measured. We found that the male hippocampus, normally larger than the female, undergoes a greater volume loss compared with females (p < 0.05). Myelination, generally greater in males, was significantly disrupted by hypoxia in neonatal male forebrain. These results support the use of this rodent model to investigate the basis of sex-related susceptibility to brain damage and develop new sex-based neuroprotective strategies.
8920949
Boys live dangerously in the womb
The growth of every human fetus is constrained by the limited capacity of the mother and placenta to deliver nutrients to it. At birth, boys tend to be longer than girls at any placental weight. Boy's placentas may therefore be more efficient than girls, but may have less reserve capacity. In the womb boys grow faster than girls and are therefore at greater risk of becoming undernourished. Fetal undernutrition leads to small size at birth and cardiovascular disorders, including hypertension, in later life. We studied 2003 men and women aged around 62 years who were born in Helsinki, Finland, of whom 644 had hypertension: we examined their body and placental size at birth. In both sexes, hypertension was associated with low birth weight. In men, hypertension was also associated with a long minor diameter of the placental surface. The dangerous growth strategy of boys may be compounded by the costs of compensatory placental enlargement in late gestation. In women, hypertension was associated with a small placental area, which may reduce nutrient delivery to the fetus. In men, hypertension was linked to the mothers' socioeconomic status, an indicator of their diets: in women it was linked to the mothers' heights, an indicator of their protein metabolism. Boys' greater dependence on their mothers' diets may enable them to capitalize on an improving food supply, but it makes them vulnerable to food shortages. The ultimate manifestation of their dangerous strategies may be that men have higher blood pressures and shorter lives than women. Am. J. Hum. Biol., 2010. © 2009 Wiley‐Liss, Inc.
8535762
The sex-specific effects of famine on the association between placental size and later hypertension.
BACKGROUND
People who had low birth weight are at increased risk of hypertension. This may reflect fetal programming by undernutrition. Placental size is also associated with hypertension. Maternal undernutrition during the Dutch famine reduced placental surface area. We examined whether maternal undernutrition altered the relationship between placental size and later hypertension.


METHODS
Retrospective cohort study among 860 subjects born in Amsterdam during 1943-47. 216 subjects were taking anti-hypertensive medication. Birth records included placental length and breadth from which we calculated its area.


RESULTS
Among men who were not in utero during the famine hypertension was associated with a small placental surface area due to a small placental breadth, and with an oval-shaped surface. The OR for hypertension was 0.83 (95% CI 0.70 to 1.00) for a 40 cm(2) increase in surface area. Among men who were in utero during the famine hypertension was associated with a large placental surface area due to a large placental breadth, and with a round-shaped surface. The OR for hypertension was 1.34 (95% CI 0.99 to 1.80) for a 40 cm(2) increase in surface area. The associations between placental size and hypertension in men who were and were not in utero during the famine were significantly different (p values for interaction = 0.008 for placental surface area, 0.001 for the breadth and 0.01 for the difference in the two diameters). Among women hypertension was not associated with placental size.


CONCLUSIONS
Our study provides the first direct evidence that changes in maternal diet during pregnancy alter the relationship between placental size and later hypertension among men but not women. We suggest that among men who were not in utero during the famine, hypertension was related to impaired implantation, whereas among men who were in utero during the famine it was related to compensatory expansion of the placental surface.
25736831
Sex differences in developmental programming models.
The theory of developmental programming suggests that diseases such as the metabolic syndrome may be 'programmed' by exposure to adverse stimuli during early development. The developmental programming literature encompasses the study of a wide range of suboptimal intrauterine environments in a variety of species and correlates these with diverse phenotypic outcomes in the offspring. At a molecular level, a large number of variables have been measured and suggested as the basis of the programmed phenotype. The range of both dependent and independent variables studied often makes the developmental programming literature complex to interpret and the drawing of definitive conclusions difficult. A common, though under-explored, theme of many developmental programming models is a sex difference in offspring outcomes. This holds true across a range of interventions, including dietary, hypoxic, and surgical models. The molecular and phenotypic outcomes of adverse in utero conditions are often more prominent in male than female offspring, although there is little consideration given to the basis for this observation in most studies. We review the evidence that maternal energy investment in male and female conceptuses may not be equal and may be environment dependent. It is suggested that male and female development could be viewed as separate processes from the time of conception, with differences in both timing and outcomes.