Does increased crypt cell proliferation impair cholesterol absorption after proximal gut resection?

Background: The effects of proximal small-bowel resection on absorption and synthesis of cholesterol are unclear. Methods: To study cholesterol absorp tion and synthesis after proximal gut resections of variable length, plasma plant sterols, cholestanol, and cholesterol precursors were measured 1 and 2 months after 50% and 75% proximal small-bowel resection or transection. To examine the effect of increased crypt cell proliferation and brush borde r development on cholesterol absorption, the results were related to the mu cosal morphology, crypt cell proliferation, and disaccharidase activities o f the remaining small bowel. Results: Campesterol levels in proportion to c holesterol decreased markedly more, and those of cholestanol markedly less, than would be expected simply due to the amount of proximal small intestin e removed, whereas sitosterol proportions decreased in proportion to the le ngth of gut resection. Campesterol proportions markedly (P=0.06) increased between 1 and 2 months after 50% resection but remained unchanged after 75% resection. Crypt cell proliferation was only increased in the 75% resectio n group (P < 0.05). The longer the proximal gut resection, the lower was th e mucosal enzyme activity. Both resection groups showed increased plasma ch olesterol precursor proportions and crypt depth (P < 0.05), whereas villus height remained unchanged. After massive proximal resection campesterol and sitosterol proportions were inversely related to crypt cell proliferation (r = -0.86-0.83, P < 0.01). Conclusions: Increased crypt cell proliferation activated by massive proximal gut resection may act as a previously unreco gnized factor in aggravating cholesterol malabsorption and retarding its re covery during the early postoperative period. These findings warrant furthe r investigation.