Small intestinal submucosa as a bioscaffold for tissue regeneration in defects of the colonic wall.

backgroundSmall intestinal submucosa (SIS) has proved considerable regenerative capacity for repair of bowel wall defects at different locations. This study assesses the effectiveness of SIS in the repair of defects at a gastrointestinal location with strong bacterial contamination.

methodsFourteen domestic pigs had a 4.5 x 1.5 cm full-thickness defect created on the wall of the descending colon. Repair was done by suturing an SIS patch to the defect. Grafts were harvested after 30, 60, and 90 days. Outcomes were evaluated on the basis of animal survival, clinical course, and macroscopic, histological, and immunohistochemical assessment.

resultsAll animals survived the scheduled observation period. No patch failure and no postoperative leakage occurred. No luminal narrowing occurred at SIS-patched colon. Morphometric examination revealed contraction of the patched area of 77% after 30 days and more than 90% after 60 and 90 days. By 60 and 90 days, all animals showed mucosal regeneration at the margins of the graft. By 90 days, regeneration of smooth muscle cells was present at the original site of the muscularis mucosae. None of the reconstructed areas showed complete mucosal coverage or regeneration of a structured muscular layer.

conclusionSIS can be used effectively for patch repair of colonic defects in a porcine model. Distinctive contraction of the reconstructed area and limited architectural regeneration of the bowel wall suggest limitation of morphologic regenerative capacities in large-bowel regeneration.