Tissue engineering of the intestine has emerged as a potential curative therapy for patients with short gut syndrome. Currently, the intestinal mucosa can be regenerated using epithelial cell clusters and polymeric scaffolds. Although the mucosa is necessary for intestinal function, it is insufficient without the muscularis of the small intestine that propels the enteric content forward. Therefore, the regeneration of the muscularis represents a critical step in realizing the clinical potential of intestinal tissue engineering. The long-term objective of the proposed research is to engineer the environment for the formation of the intestinal muscularis. Three specific aims will examine the scaffold design, signaling cues, and cellular interaction as follows. Specific Aim 1: Investigate the effects of scaffold design on muscularis formation. Sheets of aligned smooth muscle cells growing on oriented fibers will be produced. The choice of the material for the fabrication of the oriented-fiber sheets will be investigated. A spatial gradient of basic fibroblast growth factor will be created using microspheres to enhance angiogenesis in the orthogonal-layer tube. Specific Aim 2: Investigate the effect of butyrate on the phenotype of smooth muscle cells after implantation. The phenotype of the smooth muscle cells will be modulated by the delivery of butyrate in vivo. Labeled butyrate will be encapsulated in biodegradable microspheres that will release the content after a period of delay. A spatial gradient of lag time in butyrate delivery will be created to match the differential rates of smooth muscle cell proliferation in the multi- layer tube. Specific Aim 3: Investigate the effects of pacemaker cells on smooth muscle cells. To create the rhythmic contractions, we will reconstitute a network of pacemaker cells adjacent the layers of the smooth muscle cells in the contractile state. A multi-layer tube with smooth muscle cells in rolled sheets and the pacemaker cells in collagen gel surrounding the tube will form the basis of the motor unit. The effects of stem cell factor delivery, the collagen concentration, the cell density, and the arrangement of the cell types will be studied. PUBLIC HEALTH RELEVANCE: The massive loss of the small intestine results in short gut syndrome. These patients rely on intravenous nutrition that can lead to liver failure. This research will address a critical step toward the regeneration of the small intestine for patients with short gut syndrome.