Plasma lathosterol and campesterol in detection of ileal dysfunction.

Plasma lathosterol levels reflect cholesterol synthesis, especially that induced by bile acid malabsorption, whereas plasma plant sterol contents change in parallel with cholesterol and fat absorption. The significance of lathosterols and plant sterols (campesterol and sitosterol) was therefore studied in detection of ileal dysfunction in 29 patients with ileal resection (7 with no malabsorption, 8 with only bile acid malabsorption, and 15 with bile acid, fat, and cholesterol malabsorption) and in 8 jejunoileal bypass patients with fat, bile acid, and cholesterol malabsorption. Ileal dysfunction-induced faecal loss of bile acids was proportionate to cholesterol synthesis, which, in turn, was proportionate to the plasma levels of lathosterols, so that the lathosterols contents were also closely correlated (r = 0.880) to faecal bile acids. The lower the cholesterol absorption, the lower was the plasma campesterol (less consistently, beta-sitosterol) level and the higher the faecal fat. Thus, elevated plasma lathosterol content is highly suggestive of bile acid malabsorption in a patient with suspected ileal dysfunction. High plasma content of lathosterols combined with a low campesterol level points to associated fat malabsorption, indicating that the lathosterol to campesterol ratio in plasma is frequently increased in patients with ileal dysfunction associated with steatorrhoea.