Effect of bile salt-binding resins on the morphology of rat jejunum and colon (original) (raw)

1980, Digestive Diseases and Sciences

One mechanism suggested to account for the hypocholesteremic effect of dietary fibers is their ability to sequester bile salts. Since bile salts have been found to alter intestinal structure, the morphological effects of several commonly used, xenobiotic, bile salt-binding agents was investigated. Wistar rats were fed a purified stock diet, ad libitum, for 6 weeks containing either 2% cholestyramine, 2% colestipol, or 2% DEAE-Sephadex. The bile salt-binding capacity of these substances was tested in vitro using taurocholate and glycocholate. The effect of in vivo feeding of the resins was to evoke ultrastructural topographical deviations from control appearance in both jejunal and colonic mucosae. Colonic cell injury was more severe than that observed in the jejunum of both colestipol-and DEAE-Sephadex-fed animals while the reverse was true for the rats fed cholestyramine. The degree of distortion in each condition was positively correlated with the extent of bite salt-binding capability in vitro. The rank order of both effects in terms of increasing severity was DEAE-Sephadex < colestipol < cholestyramine. Cholestyramine, colestipol, and DEAE-Sephadex are synthetic, nonabsorbable anion-exchange resins which effectively bind bile acids in vitro (1, 2) and in vivo (3-5). This binding reduces the effective micellar concentration of bile acids in the upper intestinal tract, thereby decreasing the solubilization of cholesterol and of the monoglycerides and fatty acids derived from lipolysis (6). This, in turn, leads to hypolipidemia and increased fecal elimination of certain lipids (7, 8). In addition to the possible direct effects of cholestyramine on cholesterol absorption, there is also a tenfold increase in fecal excretion of the bound bile acids (9), resulting in reduced feed