Comparison of growth, neovascularization, and enzymatic function of fetal intestinal grafts in the omentum and renal capsule.

Fetal tissues are less immunogenic and may be a useful donor source for organ transplantation. This report compares the fate of fetal small bowel segments transplanted in the omentum and renal capsule of recipient syngeneic rats. Two-centimeter segments of fetal jejunum and ileum were obtained from 26 donor 19-day gestational age rat fetuses and transplanted into the subrenal capsule (n = 35) and omentum (n = 40) in syngeneic Fisher rats (weight, 150 g) as free grafts. No immunosuppression was used. At 2 weeks posttransplantation, the recipient rats underwent laparotomy and the grafts were evaluated for viability, growth, enzymatic function, and revascularization. Viable grafts were identified in 27 of 35 renal capsule grafts and 34 of 40 omental grafts. The order of magnitude of fetal growth in the omentum for jejunum was 16 +/- 10 versus ileum 23 +/- 9 (NS). However, in the renal capsule, ileal growth (15 +/- 6) was significantly greater than jejunum (8 +/- 5; P less than .01). Growth for both jejunal and ileal segments was greater in the omentum (P less than .02). The lumen of all omental grafts remained patent; however, 26 of 27 renal grafts had cystic dilatations and areas of obstruction. Microfil casts of the specimens showed vascular connections (neovascularization) between the graft and omentum, a normal serosal vascular pattern, and many submucosal capillary-like vessels. Maltase activity was measured in fetal grafts and compared with control pups bred on the same date as the donor animals. The grafts had a higher maltase level 33.4 +/- 34.6 mumol/min/g than controls 8.3 +/- 2.0 (P less than .005).(ABSTRACT TRUNCATED AT 250 WORDS)