Recipient growth and nutritional status following transplantation of segmental small-bowel allografts

Concerning small-bowel transplantation in children, the question arises whether a segmental small-bowel graft from an adult donor would permit normal growth of the young recipient. Orthotopic small-bowel transplantation was performed in 4- to 6-week-old Lewis rats weighing 100-135 g. The entire small bowel of the recipient was replaced with an intestinal allograft consisting of the entire small bowel (N = 6), the jejunum (N = 6), or the ileum (N = 6) from adult Brown Norway rats. Immunosuppression with cyclosporine (15 mg/kg im) on alternate days for 4 weeks achieved graft acceptance of indefinite duration. Six and twelve months after transplantation, all recipients demonstrated normal global nutritional parameters (hematocrit, serum albumin) and gained weight at a rate comparable to that for age-matched controls. Nutritional deficiencies did not become apparent clinically. By 10 to 12 months, the levels of fat-soluble vitamins (A and E) were reduced significantly in recipients of segmental grafts. Vitamin B₁₂ levels were also reduced but not significantly. Fecal fat was significantly elevated in all rats with grafts (3.2 ± 1.0 to 4.8 ± 0.9 g fat/100 g stool; controls, 1.8 ± 0.4), but the increase was most pronounced in those with jejunal grafts (4.7 ± 0.9). This was paralleled by a reduction in serum triglyceride levels in all transplanted rats, a reduction which reverted to normal by 10 to 12 months for rats with entire small-bowel grafts but not for those with segmental grafts. Graft biopsy demonstrated normal intestinal architecture with villus hyperplasia of segmental grafts. Our findings indicate that allografts of the entire adult small bowel permit normal growth of young recipients, and that segmental grafts (ileal > jejunal), within the limits of their respective absorptive capacities, possess sufficient functional reserve and adaptability to provide caloric nutritional balance and thus normal growth of the recipients.