ADAPTIVE LIPID-METABOLISM AFTER ILEAL AUTOTRANSPLANTATION IN PIGS WITH PROXIMAL GUT RESECTION

Background. Transplantation of the small intestine impairs intestinal absorptive function, but the adaptive response of a segmental graft is unknown. The aim of this study was to investigate the effects of ilea l autotransplantation on the adaptive absorption and metabolism of lip ids in pigs that had undergone proximal gut resection. Methods. Serum lipids, plasma vitamins A and E, absorption and excretion of cholester ol, bile acids and fat, plasma cholesterol precursor and plant sterol proportions to cholesterol (respective markers of cholesterol synthesi s and absorption) enteric structure, and transit were determined 4, 8, and 24 weeks after 7.5 % proximal resection with (n = 15) or without (n = 15) autotransplantation of the remaining Ileum. Results. As compa red with pigs that underwent proximal gut resection, the additional au totransplantation reduced the adaptive increase in total serum and hig h-density lipoprotein cholesterol, plasma plant sterol proportions and vitamin E concentrations, cholesterol and fat absorption efficiency, and villus height (p < 0.05 for all) during the 14 postoperative weeks and resulted in increases of up to 4.6, 2.7, 1.3, and 2.1 times the p lasma cholesterol precursors (p < 0.005), fecal excretion of bile acid s (p < 0.0005), neutral steroids (p < 0.005), and net elimination of c holesterol (p < 0.0005), respectively. Cholesterol and fat absorption and plasma plant sterols were significantly enhanced between 8 and 14 weeks after autotransplantation (p < 0.05, p < 0.005, and p < 0.05, re spectively), whereas fecal elimination of cholesterol remained increas ed until the end of the follow-up. Conclusions. Autotransplantation of the ileum in pigs that have undergone proximal small bowel resection disturbs the adaptive absorption of cholesterol, bile acids, fat, and fat-soluble vitamins, resulting, through increased fecal elimination o f cholesterol, in decreased serum cholesterol despite a marked compens atory increase in cholesterol synthesis.