NUTRITIONAL PARAMETERS AND RELEASE OF NEU ROTENSIN FOLLOWING SMALL-BOWEL RESECTION, SYNGENEIC, OR ALLOGENEIC SEGMENTAL TRANSPLANTATION IN RATS

The aim of the following study was to gain some insight into the funct ional characteristics of different portions of the small intestine aft er either partial resection or syngeneic and allogeneic transplantatio n 3 months postoperatively. Nutritional parameters (serum albumin leve ls, serum triglyceride levels, maltose absorption, excretion of fecal fat) and fat-stimulated neurotensin release were determined in Lewis r ats that underwent small-bowel resection (n = 21), syngeneic (Lewis--> Lewis, n = 21), or allogeneic transplantation (Brown Norway-->Lewis, n = 24). The length of the remnant, isograft, or allograft was 27 cm (i .e., one-third of the rat small intestine) and consisted of the proxim al (n = 7), middle (n = 7), or distal (n = 7) portion. Three postopera tive deaths were due to ileus or pneumonia. After allotransplantation cyclosporine (15 mg/kg body wt. s.c.) was administered for graft accep tance. The control group was not operated upon, but was composed of we ight- and age-matched Lewis rats (n = 7). We found that resection of t wo-thirds of the small intestine led to significantly lower levels of albumin and triglycerides in all three portions investigated (P < 0.01 ), but did not affect maltose absorption. Excretion of fecal fat was e levated significantly only after distal resection (P < 0.05). When com pared to resected animals, syngeneic transplantation did not affect th e nutritional parameters, but caused a significantly higher hormone re lease (P < 0.05) in all three different intestinal grafts. Allogeneic transplantation was successful when the middle or distal portion was g rafted. All recipients of proximal allografts showed a severe loss of body weight and died between day 8 and 1 0 after transplantation. Post mortem examination revealed no signs of acute rejection. We conclude t hat when transplantation of short intestinal segments is considered, i t is of vital importance to take into account the functional differenc es and the influence of immunosuppressive drug therapy in the regulati on of bowel function.