ABSORPTION, EXCRETION, AND DISTRIBUTION OF PLANT STEROLS AFTER PROXIMAL GUT RESECTION AND AUTOTRANSPLANTATION OF PORCINE ILEUM

Contribution of different gut segments to plant sterol absorption, ada ptation of plant sterol absorption after partial small bowel resection , and effects of gut transplantation (necessitates extrinsic autonomic denervation and lymphatic disruption) on plant sterol biodynamics are unclear. We studied the consequences of massive proximal small bowel resection and autotransplantation of the remaining ileum on the adapti ve absorption and biodynamics of plant sterols. Dietary, fecal, biliar y, hepatic and plasma plant sterols, fecal elimination and absorption of cholesterol, small bowel morphology, and intestinal transit were de termined before (n = 5) and at 4, 8, and 14 wk after resection of the proximal 75% of the jejunoileum (n = 15) and autotransplantation of th e remaining ileum (n = 15) or transection (n = 5). Proximal gut resect ion significantly reduced cholesterol absorption efficiency; percentag e absorption and biliary secretion of plant sterols; plasma, biliary a nd hepatic campesterol-to-cholesterol proportions; and sitosterol prop ortions in plasma and bile. Autotransplantation of the remaining ileum further significantly decreased cholesterol absorption efficiency; pe rcentage absorption and biliary secretion of campesterol; campesterol proportions in plasma, bile and liver; and plasma proportions of sitos terol while increasing fecal excretion of neutral and acidic steroids. Plasma proportions of the two plant sterols, but absorption of just c ampesterol, were gradually improved with increasing cholesterol absorp tion and villus height after proximal gut resection; the same result w as observed to a lesser degree after ileal autotransplantation. In add ition, significant positive correlations were found between percentage cholesterol and campesterol absorption and the plasma plant sterol pr oportions in both proximal resection groups, between campesterol absor ption and ileal villus height in the resection group, and between camp esterol absorption and intestinal transit time in the autotransplantat ion group. In conclusion, plasma campesterol and sitosterol closely re flect absorption of cholesterol and plant sterols from intact and auto transplanted ileum during adaptation to proximal gut resection. A loss of proximal gut absorptive surface impairs cholesterol and campestero l absorption more than sitosterol absorption, the rat ter being appare ntly less dependent on available jejunal villus surface area.