LENGTH OF TRANSPLANTED SMALL-BOWEL REQUIRED FOR ADEQUATE WEIGHT-GAIN IN RATS

Progress has been made toward developing a clinically successful small -bower transplant procedure, but there has been little research concer ning the functional aspects of the transplanted small bowel. Using a r at model, our study examined the length of transplanted small bowel re quired to provide adequate weight gain. The rats were divided into six groups; groups 1 and 2 were considered controls. Group 1 (n = 6) unde rwent a gastrostomy. Group 2 (n = 3) underwent a jejunoileectomy follo wed by re-establishment of intestinal continuity and anastomosis of th e native proximal small bowel to an abdominal stoma and the distal por tion to the ascending colon. Groups 3 (n = 5), 4 (n = 4), 5 (n = 5), a nd 6 (n = 4) underwent small-bower transplantation, receiving 100%, 50 %, 25%, and 15% transplants, respectively. The donor small-bowel anast omoses were the same as the native small-bowel anastomoses in group 2. All of the rats began to produce stool within 4 days of becoming depe ndent upon the transplanted small bowel. By the end of postoperative w eek 4, there was no significant difference between the percentages of preoperative body weight in groups 1-4 (range 125.7% 130.0%). Although the weight gain in group 5 was significantly less than that in groups 1-4 (P < 0.05), it was adequate (111.8%); group 6 animals lost weight (94.7%). It is concluded that a 50% or more small-bowel transplant wi th or without an ileocecal valve provides ample weight gain; minimally adequate weight gain is achieved by a 25% transplant without an ileoc ecal valve; and the graft begins to function soon after transplantatio n.