IMPAIRED ABSORPTION OF CHOLESTEROL AND BILE-ACIDS IN PATIENTS WITH ANILEOANAL ANASTOMOSIS

Background-No data exist on cholesterol absorption in patients with an ileoanal anastomosis (IAA). Aims-To study cholesterol absorption and its effects on cholesterol and bile acid metabolism in patients with a n IAA. Patients and methods-Cholesterol absorption, and serum, biliary , and faecal lipids were studied in 24 patients with an IAA and 20 con trols. Results-Fractional cholesterol absorption was significantly low er in the patients (36% versus 47% in controls). Surprisingly, the cal culated intestinal influx of endogenous cholesterol was reduced so tha t the absolute absorption of cholesterol was decreased; elimination of cholesterol as faecal neutral steroids remained normal. Thus, the sli ghtly increased cholesterol synthesis was mainly due to increased faec al bile acid excretion, which, in turn, was associated with reduced ab sorption and biliary secretion of bile acids. Serum total and low dens ity lipoprotein (LDL) cholesterol and LDL triglycerides were lower in the patients. Molar percentage and saturation index of biliary cholest erol were slightly higher in patients with an IAA. Proportions of seco ndary bile acids in bile and faeces were diminished, and faecal uniden tified bile acids were higher in patients. Conclusions-Cholesterol abs orption is significantly impaired in patients with an IAA, and is clos ely related to changes in serum and biliary Lipids observed in these p atients.