Serum cholesterol precursors, cholestanol, and plant sterols in primary biliary cirrhosis

We measured serum cholesterol precursors (squalene, delta 8-cholestenol, desmosterol, lathosterol, cholestanol) and plant sterols (campesterol, sitosterol, and avenasterol) from 11 patients (one man) with primary biliary cirrhosis (PBC) and 13 healthy women matched for age and weight. In PBC serum total cholesterol was increased (9.4 versus 5.9 mmol/l; p less than 0.05), whereas serum cholestanol in terms of mmol/mol of cholesterol was elevated fourfold. In similar terms, serum plant sterols, especially sitosterol and avenasterol, were modestly increased, whereas most of serum cholesterol precursors were decreased. The serum contents of cholestanol were negatively associated with those of serum cholesterol precursors and positively with those of sitosterol and avenasterol with the serum cholesterol concentration. The liver function tests were positively related to serum cholestanol contents (r value ranged from 0.588 to 0.839 for alkaline phosphatase, aspartate aminotransferase, alanine amino-transferase, and bilirubin). The findings suggest that in cholestatic liver disease reduced serum cholesterol precursor contents reflect reduced cholesterol synthesis, whereas increased serum plant sterol and cholestanol contents are determined mainly by impaired biliary elimination.