Steven Farber, Ph.D., assistant professor of microbiology and immunology at Jefferson Medical College of Thomas Jefferson University in Philadelphia, Eric Smart, Ph.D., at the University of Kentucky and their co-workers have found that treating hypercholesterolemic mice with the drug ezetimibe (Zetia) disrupts a complex of two proteins in the intestine. At the same time, they used "antisense" molecules to prevent the formation of the complex in zebrafish, resulting in impaired cholesterol absorption in the intestine. The results suggest that these proteins are integral parts of an unidentified cholesterol transport system in the intestine.
A better understanding of the mechanisms behind cholesterol transport and absorption in the intestine could lead to improved therapies for obesity, diabetes and cardiovascular disease.
Dr. Farber and his colleagues report their findings February 23, 2004 in the Proceedings of the National Academy of Sciences. Specifically, the researchers found that two proteins Caveolin 1 and Annexin 2 were bound extremely tightly in the intestines. When this association was disrupted in zebrafish embryos, they absorbed a cholesterol "analog" more poorly. The scientists also found a similar close association of these proteins in mouse intestinal cells not found in other cells.
When the team treated mice that were fed a high fat Western diet with Zetia, the
two proteins separated. "This was truly an unexpected result," Dr. Farber says. "How cholesterol levels can influence the ability of Zetia to disrupt the complex remains a mystery," he says, adding that both he and Dr. Smart plan to study the question in the near future.
Ezetimibe blocks cholesterol absorption in the intestines, and as a result, scientists have inferred the existence of a chol
Contact: Steve Benowitz or Phyllis Fisher
Thomas Jefferson University