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OBJECTIVE:: Rescue with tissue-engineered small intestine (TESI) after massive small bowel resection (MSBR).SUMMARY BACKGROUND DATA:: Short bowel syndrome is a morbid product of massive small bowel resection. We report the first replacement of a vital organ by tissue engineering with TESI after MSBR.METHODS:: Ten male Lewis rats underwent TESI implantation with green fluorescent protein (GFP)-marked cells (TESI+, n = 5) or sham laparotomy (TESI−, n = 5) followed by MSBR. Side-to-side anastomosis of TESI to proximal small intestine was performed or omitted. TESIØ animals underwent implantation of engineered intestine with no further surgery. Weights were measured QOD until day 40. Transit times were measured. DNA assay was performed with computer morphometry. Northern blots of RNA were probed for intestinal alkaline phosphatase (IAP) and villin. Hematoxylin and eosin, S100, and smooth muscle actin immunohistochemistry were performed. Blood was collected at sacrifice.RESULTS:: All 10 rats initially lost then regained weight. The initial rate of weight loss was higher in TESI+ versus TESI−, but the nadir was reached a week earlier with more rapid weight gain subsequently to 98% preoperative weight on day 40 in animals with engineered intestine versus 76% (P < 0.03). Serum B12 was higher at 439 pg/mL versus 195.4 pg/mL. IAP mRNA appeared greater in TESI+ than TESIØ, with constant villin levels. Histology revealed appropriate architecture including nerve. GFP labeling persisted.CONCLUSIONS:: Anastomosis of TESI significantly improved postoperative weight and B12 absorption after MSBR. IAP, a marker of differentiation in intestinal epithelium, is present in TESI, and GFP labeling was accomplished. [ABSTRACT FROM AUTHOR]

OBJECTIVE Novel production and in vitro characterization of tissue engineered colon.SUMMARY BACKGROUND DATA The colon provides important functions of short chain fatty acid production, sodium and water absorption, and storage. We report the first instance of tissue-engineered colon (TEC) production from autologous cells and its in vitro characterization.METHODS Organoid units, mesenchymal cell cores surrounded by a polarized epithelia derived from full thickness sigmoid colon dissection from neonatal Lewis rats, adult rats, and tissue engineered colon itself, were implanted on a polymer scaffold into the omentum of syngeneic hosts. TEC was either anastomosed at 4 weeks or excised for Üssing chamber studies or histology, immunohistochemistry, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick end labeling assay.RESULTS TEC was generated by 100% of all animals without regard to tissue source, the first instance of engineered intestine from adult cells or an engineered tissue. TEC architecture is identical to native with muscularis propria staining for actin, acetylcholinesterase detected in a linear distribution in the lamina propria, S100-positive cells, ganglion cells, and a terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick end labeling assay similar to native colon. Üssing chamber data indicated in vitro function consistent with mature colonocytes, and a positive short circuit current response to theophylline indicating intact ion transfer. TEM showed normal microarchitecture. Colon architecture was maintained in anastomosis with gross visualization of fluid uptake.CONCLUSIONS TEC can be successfully produced with fidelity to native architecture and in vitro function from neonatal syngeneic tissue, adult tissue, and TEC itself. [ABSTRACT FROM AUTHOR]