Influence of a highly purified senna extract on colonic epithelium

Background: Chronic use of sennoside laxatives often causes pseudomelanosis coli. A recent study suggested that pseudomelanosis coli is associated wit h an increased colorectal cancer risk. A single high dose of highly purifie d senna extract increased proliferation rate and reduced crypt length in th e sigmoid colon compared to historical controls. Aims: To evaluate in a con trolled study the effects of highly purified senna extract on cell prolifer ation and crypt length in the entire colon and on p53 and bcl-2 expression. Methods: Addition of a senna extract to colonic ravage was studied in 184 consecutive outpatients. From 32 randomised patients, 15 with sennosides (S en), 17 without (NSen), biopsies were taken. Proliferative activity was stu died in 4 areas of the colon, using 5-bromo-2'-deoxyuridine labelling and i mmunohistochemistry (labelling index, LI). Expression of p53 and bcl-2 in t he sigmoid colon was determined immunohistochemically, Results: Crypts were shorter in Sen than in NSen in the transverse and sigmoid colon. LI was hi gher in Sen than in NSen in the entire colon. No difference in p53 expressi on was seen. Bcl-2 expression was higher in both groups when crypts were sh orter and/or proliferation was increased. Conclusion: Sennosides induce acu te massive cell loss probably by apoptosis, causing shorter crypts, and inc reased cell proliferation and inhibition of apoptosis to restore cellularit y. These effects may reflect the mechanism for the suggested cancer-promoti ng effect of chronic sennoside use. Copyright (C) 2000 S. Karger AG, Basel.