P3.25: INTESTINAL CHOLESTEROL ABSORPTION IS PRESERVED AFTER ISOLATED INTESTINAL TRANSPLANTATION DESPITE INCREASED CHOLESTEROL SYNTHESIS

Abstract

Introduction. We aimed to investigate cholesterol metabolism in relation to nutritional status and serum lipids after isolated intestinal transplantation (ITX). Methods. Seven patients who had undergone isolated ITX including ascending colon at median age of 17.3 (range, 5.9–52) years due to intestinal failure caused by chronic intestinal pseudo obstruction (n=5) and total intestinal aganglionosis (n=2) were included median 3.5 (IQR, 2.9–7.4) years after ITX. Blood samples were analyzed for fat-soluble vitamins (A, E, D-25-OH), prealbumin, and cholesterol (total, LDL, HDL) and triglyceride levels. In six patients and 14 heathy age- and gender-matched controls, cholesterol metabolism was assessed with serum non-cholesterol sterols. The ratios to cholesterol (102 x µmol/mmol of cholesterol) of the serum cholesterol precursors (cholestenol, desmosterol and lathosterol) reflect cholesterol synthesis, while those of plant sterols (campesterol, sitosterol, and avenasterol) and cholestanol reflect cholesterol absorption efficiency. Lathosterol/cholestanol ratio reflects the balance between cholesterol absorption and synthesis and campesterol/cholestanol ratio reflects the plant sterol intake. Results. Patients were on tacrolimus-based maintenance immunosuppression without current signs of acute or chronic transplant rejection. All patients had weaned off PN median 39 days (IQR 21–215) after ITX and had a median body mass-index of 18.2 (IQR, 16.6–19.1) kg/m2. The levels of fat-soluble vitamins and prealbumin were mostly in normal range while plasma HDL cholesterol was low and triglyceride levels were increased in most patients (Table 1). Cholesterol precursor levels were significantly increased while plant sterols and cholestanol were not significantly different between patients and controls (Table 2). Increased lathosterol/cholestanol-ratio suggest that cholesterol synthesis markedly predominated absorption in patients’ whole body cholesterol homeostasis while the campesterol/cholestanol ratio suggest that the plant sterol intake was decreased in patients compared to controls (Table 2). Conclusion. Following isolated ITX, intestinal cholesterol absorption efficiency is preserved, while cholesterol synthesis increases likely to compensate malabsorption of bile acids. Satisfactory nutritional status, normal fat-soluble vitamin levels and preserved cholesterol absorption suggest that the compensatory increase was sufficient to maintain adequate lipid absorption.