Psyllium augments the cholesterol-lowering action of cholestyramine in hamsters by enhancing sterol loss from the liver.
OBJECTIVE
Psyllium hydrophilic mucilloid is a nonabsorbable soluble fiber that lowers plasma cholesterol levels in several species, including humans. However, its mechanism of action has not been fully elucidated. Therefore, using a hamster model, experiments were performed to determine whether psyllium given alone or in combination with a submaximal dose of cholestyramine blocks intestinal cholesterol absorption.


METHODS
The efficiency of cholesterol absorption and concentrations of plasma and hepatic total cholesterol were measured in male hamsters fed a cholesterol-enriched chow diet (0.1%) that contained either avicel (cellulose) (7.5%), surfomer (3%), cholestyramine (1% or 3%), or psyllium (7.5%) as single agents or a fixed level of cholestyramine (1%) combined with variable levels of psyllium (2%, 4%, 6%, or 8%).


RESULTS
Psyllium, cholestyramine, and surfomer, when given alone, markedly lowered plasma and hepatic cholesterol concentrations. Surfomer, and cholestyramine at the higher dose (3%), blocked cholesterol absorption by 54% and 75%, respectively, whereas psyllium had no effect. Combining psyllium with a submaximal dose of cholestyramine augmented the cholesterol-lowering action of the resin without effecting any marked change in the level of cholesterol absorption, except at the highest dose used.


CONCLUSIONS
Psyllium, given either as a single agent or as an adjunct to treatment with cholestyramine, exerts a significant hypocholesterolemic effect by enhancing net negative sterol balance across the liver.
Turley
S D
SD
Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas.
Daggy
B P
BP
Dietschy
J M
JM
D000818:Animals; D002784:Cholesterol / Q000097:blood* / Q000493:pharmacokinetics; D002792:Cholestyramine Resin / Q000494:pharmacology*; D006224:Cricetinae; D003864:Depression, Chemical; D007408:Intestinal Absorption / Q000187:drug effects; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008297:Male; D008647:Mesocricetus; D011108:Polymers / Q000494:pharmacology; D011620:Psyllium / Q000494:pharmacology*; D013261:Sterols / Q000378:metabolism*; D013386:Succinates / Q000494:pharmacology
D011108:Polymers; D013261:Sterols; D013386:Succinates; D002792:Cholestyramine Resin; D011620:Psyllium; C025487:surfomer; D002784:Cholesterol