1012000
Apolipoprotein CIII Overexpressing Mice Are Predisposed to Diet-Induced Hepatic Steatosis and Hepatic Insulin Resistance
Nonalcoholic fatty liver disease (NAFLD) and insulin resistance have recently been found to be associated with increased plasma concentrations of apolipoprotein CIII (APOC3) in humans carrying single nucleotide polymorphisms within the insulin response element of the APOC3 gene. To examine whether increased expression of APOC3 would predispose mice to NAFLD and hepatic insulin resistance, human APOC3 overexpressing (ApoC3Tg) mice were metabolically phenotyped following either a regular chow or high-fat diet (HFD). After HFD feeding, ApoC3Tg mice had increased hepatic triglyceride accumulation, which was associated with cellular ballooning and inflammatory changes. ApoC3Tg mice also manifested severe hepatic insulin resistance assessed by a hyperinsulinemic-euglycemic clamp, which could mostly be attributed to increased hepatic diacylglycerol content, protein kinase C-ε activation, and decreased insulin-stimulated Akt2 activity. Increased hepatic triglyceride content in the HFD-fed ApoC3Tg mice could be attributed to a ≍70% increase in hepatic triglyceride uptake and ≍50% reduction hepatic triglyceride secretion. Conclusion: These data demonstrate that increase plasma APOC3 concentrations predispose mice to diet-induced NAFLD and hepatic insulin resistance. (Hepatology 2011;54:1650-1660)
24209170
Targeted expression of catalase to mitochondria prevents age-associated reductions in mitochondrial function and insulin resistance.
Aging-associated muscle insulin resistance has been hypothesized to be due to decreased mitochondrial function, secondary to cumulative free radical damage, leading to increased intramyocellular lipid content. To directly test this hypothesis, we examined both in vivo and in vitro mitochondrial function, intramyocellular lipid content, and insulin action in lean healthy mice with targeted overexpression of the human catalase gene to mitochondria (MCAT mice). Here, we show that MCAT mice are protected from age-induced decrease in muscle mitochondrial function (∼30%), energy metabolism (∼7%), and lipid-induced muscle insulin resistance. This protection from age-induced reduction in mitochondrial function was associated with reduced mitochondrial oxidative damage, preserved mitochondrial respiration and muscle ATP synthesis, and AMP-activated protein kinase-induced mitochondrial biogenesis. Taken together, these data suggest that the preserved mitochondrial function maintained by reducing mitochondrial oxidative damage may prevent age-associated whole-body energy imbalance and muscle insulin resistance.
17577030
Human originated bacteria, Lactobacillus rhamnosus PL60, produce conjugated linoleic acid and show anti-obesity effects in diet-induced obese mice.
Many previous studies have reported that conjugated linoleic acid could be produced by starter culture bacteria, but the effects of the bacteria were not investigated. Moreover, there was no evidence of the conjugated linoleic acid-producing bacteria having potential health or nutritional effects related to conjugated linoleic acid, including reducing body fat. Here, we investigated the anti-obesity effect of Lactobacillus rhamnosus PL60, a human originated bacterium that produces t10, c12-conjugated linoleic acid, on diet-induced obese mice. After 8 weeks of feeding, L. rhamnosus PL60 reduced body weight without reducing energy intake, and caused a significant, specific reduction of white adipose tissue (epididymal and perirenal). Although the size of epididymal adipocytes was not reduced by L. rhamnosus PL60, apoptotic signals and UCP-2 mRNA levels increased in adipose tissue. Liver steatosis, a well known side effect of CLA, was not observed by L. rhamnosus PL60 treatment; on the contrary it seemed to be normalized. Results showed that the amount of conjugated linoleic acid produced by Lactobacillus rhamnosus PL60 was enough to produce an anti-obesity effect.
43129468
Trends in Socioeconomic Disparities in Organized and Opportunistic Gastric Cancer Screening in Korea (2005-2009)
Background: A growth of consensus and increasing activities related to organized cancer screening programs has occurred in Korea since 1999. It is important to assess disparities in the fight against cancer, and it is crucial to identify particular groups that may be experiencing a high burden of cancer-related illness. Methods: Data from 8,160 men and women ages >40 years from the 2005 to 2009 Korean National Cancer Screening Survey were used to analyze the relationship between socioeconomic position and receiving upper gastrointestinal series or upper endoscopy within the past 2 years. We used absolute and relative concentration indexes, that is, summary measures of disparity based on both rate differences and rate ratios. Results: For organized screening, the education disparity declined, but the income disparity index increased, indicating that participation in organized screening was relatively more concentrated among the lower-income groups. For opportunistic screening, income and education disparities increased due to the widening of socioeconomic differences. Conclusions: The results of this study suggested progress toward socioeconomic disparity-related goals in organized screening for gastric cancer. However, the income disparity trends in organized screening may change in a manner similar to those in opportunistic screening in the future because of the much faster rate of organized screening uptake by those higher on the socioeconomic scale. Impact: This study addresses the routine monitoring of coverage of screening among different socioeconomic groups and could be used to inform polices to reduce disparity in coverage. Cancer Epidemiol Biomarkers Prev; 19(8); 1919–26. ©2010 AACR.
20659139
Diffusion-weighted imaging in transient global amnesia exposes the CA1 region of the hippocampus
IntroductionTransient global amnesia (TGA) is characterized by a sudden onset of anterograde amnesia without alteration of consciousness or personal identity. Interestingly, recent studies have reported a high frequency of small high-signal abnormalities in the hippocampus with diffusion-weighted (DW) imaging, and ischemia has been proposed as an etiology of TGA. We hypothesized that TGA lesions occur preferentially in the CA1 region of the hippocampus, known to be susceptible to ischemia.MethodsOver a 30-month period 34 patients with TGA underwent MRI including DW imaging within 4 days of symptom onset. Patients with high-signal abnormalities in the hippocampus on the initial DW images underwent subsequent DW and T2-weighted imaging in the coronal plane to identify the precise lesion locations.ResultsFourteen patients had small (1–3 mm) high-signal abnormalities in the hippocampus unilaterally on DW images. One of these patients had two lesions in one hippocampus and therefore in total 15 lesions were identified: four in the hippocampal head, and 11 in the body. Eleven lesions in ten patients with available coronal images were clearly demonstrated on both coronal DW and T2-weighted images and were localized to the lateral portion of the hippocampus, corresponding to the CA1 region.ConclusionLesions associated with TGA were localized exclusively to the lateral portion of the hippocampus corresponding to the CA1 region. This finding supports the ischemic etiology of TGA; however, the pathophysiological mechanism involved requires further study.
42111963
Effects of insulin-like growth factor binding protein-3 and farnesyltransferase inhibitor SCH66336 on Akt expression and apoptosis in non-small-cell lung cancer cells.
BACKGROUND
Overexpression of insulin-like growth factor binding protein-3 (IGFBP-3) induces apoptosis in non-small-cell lung cancer (NSCLC) cells in vitro and in vivo. However, Ras-mediated signaling pathways could develop resistance to apoptotic activities of IGFBP-3 in NSCLC cells. We thus evaluated the therapeutic potential of the combination of IGFBP-3 and SCH66336, a farnesyltransferase inhibitor that blocks Ras activation, in NSCLC cell lines.


METHODS
The effects of the combination of adenoviral IGFBP-3 (Ad-IGFBP3) and SCH66336 on proliferation and apoptosis of NSCLC cell lines (H1299, H596, A549, H460, H358, H322, and H226B) were assessed in vitro and in vivo by using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a flow cytometry-based terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling assay, western blot analyses, and an NSCLC xenograft tumor model. The specific effects of Ad-IGFBP 3 and SCH66336 on mitogen-activated protein kinase and Akt were assessed by using adenoviral vectors that express constitutively active MEK1 or constitutively active Akt. Synergy was assessed by median effect analysis.


RESULTS
The combination of Ad-IGFBP3 and SCH66336 had synergistic antiproliferative effects in five cell lines (H1299, H596, A549, H460, and H322). Antiproliferative effects were accompanied by increased apoptosis in H460 cells in vitro. Overexpression of a constitutively active Akt but not a constitutively active MEK-1 rescued H460 cells from apoptosis induced by single or combined treatment of Ad-IGFBP3 and SCH66336. In H1299 tumor xenografts, Ad-IGFBP3 and SCH66336 was associated with decreased tumor volume, increased apoptosis, and decreased Akt levels.


CONCLUSIONS
The combination of Ad-IGFBP3 and SCH66336 decreased Akt expression and increased apoptosis in NSCLC cells in vitro and in vivo. Simultaneous treatment with IGFBP-3 and SCH66336 may have the potential to be an effective therapeutic strategy in NSCLC.
996215
Inducible nitric oxide synthase (iNOS) expression is increased in lipopolysaccharide (LPS)-stimulated diabetic rat glomeruli: effect of ACE inhibitor and angiotensin II receptor blocker.
Previously, we reported that high glucose enhanced cytokine-induced nitric oxide (NO) production by rat mesangial cells (MCs), and that the enhanced expression of the iNOS pathway may promote extracellular matrix accumulation by MCs. The present study was designed to examine whether the iNOS pathway is pathologically altered in experimental diabetic nephropathy, and whether therapy with angiotensin converting enzyme (ACE) inhibitor (imidapril: I) or angiotensin II type I receptor (AT1) blocker (L-158,809: L), ameliorates these changes. Male Sprague-Dawley rats were injected with diluent (control: C) or streptozotocin. At sacrifice after 4, 8 and 12 weeks, rats underwent either a 4 hour placebo or an intraperitoneal lipopolysaccharide (LPS, 2 mg/kg) challenge. Systolic blood pressure (SBP) and urinary protein excretion (UPE) increased significantly in diabetic (D) rats compared with C. The basal expression of glomerular iNOS mRNA was increased in D rats compared with that of C rats, by reverse- transcription (RT)-polymerase chain reaction (PCR), whereas there was no significant difference in the level of protein by Western blot analysis. Upon LPS stimulation, the iNOS mRNA and protein expression was significantly elevated in D rats. In D rats, this up-regulation, of LPS-stimulated iNOS expression, was equally ameliorated both by I and L in mRNA and protein levels. From immunohistochemistry (IHC), there was a negative staining for the iNOS within the glomeruli of five C rats without LPS treatment, but one of four rats, with LPS treatment, showed minimal iNOS staining in the glomeruli. In D rats, the glomerular mesangium and podocytes were positive for iNOS in each of three out of five rats with, and without, LPS treatment. In conclusion, LPS-stimulated glomerular iNOS expression was enhanced in diabetic pnephropathy, and the activation of angiotensin II may play a role in this enhancement.
31435250
Multiple forms of secretory phospholipase A2 in plants.
Multiple secretory phospholipase A2 (sPLA2) genes have been identified in plants and encode isoforms with distinct regulatory and catalytic properties. Elucidation of this genetic and biochemical heterogeneity has provided important clues to the regulation and function of the individual enzymes. An increasing body of evidence shows that their lipid products, lysophospholipids and free fatty acids, mediate a variety of cellular responses, including plant growth, development, and responses to stress and defense. This review discusses the newly-acquired information on plant sPLA2s including the molecular and biochemical characteristics, and signaling functions of each isoform.