SERUM CHOLESTANOL, CHOLESTEROL PRECURSORS AND PLANT STEROLS IN DIFFERENT INFLAMMATORY BOWEL DISEASES

The role of cholestasis and ileal dysfunction on sterol metabolism was studied in 79 patients with inflammatory bowel diseases (IBDs) and in 23 irritable bowel syndrome (IBS) controls by determining serum stero l/cholesterol proportions. The sterols included cholesterol precursors (Delta(8)-cholestenol, desmosterol and lathosterol), markers of chole sterol synthesis, cholestanol and plant sterols (campesterol and sitos terol), markers of cholesterol absorption and biliary secretion. The I BD patients were subgrouped into distal ulcerative colitis (dUC, n = 2 1), pancolitis (pUC, n = 29), ileal Crohn's disease (iCD, n = 20) and colonic Crohn's disease (cCD, n = 9). The cholestanol proportions were increased in the 3 colonic IBD groups, up to two times in cCD patient s and seven times in a case with clinically overt primary sclerosing c holangitis, but were within the control IBS levels in the patients wit h ICD. The sitosterol, but not campesterol, proportion was significant ly increased only in the pUC group. In the iCD group only the serum pr ecursor sterol proportions, especially those for Delta(8)-cholestenol and lathosterol, were elevated probably due to ileal dysfunction induc ed bile acid malabsorption and compensatorily increased cholesterol sy nthesis. In conclusion, the findings suggest that the increased choles tanol proportion in colonic IBD is determined mainly by impaired bilia ry elimination of this sterol, while in ileal affision the dominating change in sterol balance is activated cholesterol synthesis. Thus incr eased serum cholestanol is a novel finding in colonic IBD, apparently indicating the presence of subclinical cholestasis in a marked number (20-50%) of IBD patients.