News Release 

CFTR inhibition: The key to treating bile acid diarrhea?

Federation of American Societies for Experimental Biology

Estimates are that roughly 1 percent of people in Western countries may have bile acid diarrhea, including patients with Crohn's disease, ileal resection, diarrhea-predominant irritable bowel syndrome (IBS-D), and chronic functional diarrhea. Current management for bile acid diarrhea has demonstrated limited efficacy, with some therapies producing significant side effects. A recent study published in The FASEB Journal explored the efficacy of CFTR (cystic fibrosis transmembrane conductance regulator) inhibition to reduce excessive secretion in the colon due to bile acids.

Researchers studied cell culture models of human intestinal cells. Based on prior studies showing that chenodeoxycholic acid (CDCA) increases secretion in the colon and is linked to CFTR activation, researchers added CDCA to the cultures, which caused an increase in CFTR activity. They then added CFTR inhibitors to the cultures and used short-circuit current measurement to measure CFTR activity. Researchers found that CFTR inhibitors including investigational drug (R)-BPO-27 were able to fully block the increased CFTR activity.

"Bile acid diarrhea is a common problem for which therapeutic options are limited and often ineffective," said Alan S. Verkman, MD, PhD, a researcher within the Departments of Medicine and Physiology at the University of California, San Francisco. "Inhibition of chloride and fluid secretion in the intestine by a CFTR inhibitor offers a new therapeutic option to reduce diarrhea associated with excess bile acids."

Motivated by data implicating CFTR as a major determinant of bile acid secretion, the research team also tested the CFTR inhibitor in a rat model of bile acid diarrhea involving direct infusion of bile acids into the colon. Once again, (R)-BPO-27 was effective; this time, in reducing the increased stool water content.

"To see a physiologist as talented as Alan Verkman, and his colleagues, enter this field and offer such insights is a significant advance," said Thoru Pederson, PhD, Editor-in-Chief of The FASEB Journal.

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This research was supported by grants from National Institutes of Health and the Cystic Fibrosis Foundation.

The FASEB Journal is published by the Federation of the American Societies for Experimental Biology (FASEB). The world's most cited biology journal according to the Institute for Scientific Information, it has been recognized by the Special Libraries Association as one of the top 100 most influential biomedical journals of the past century.

FASEB is composed of 29 societies with more than 130,000 members, making it the largest coalition of biomedical research associations in the United States. FASEB's mission is to advance health and well-being by promoting research and education in biological and biomedical sciences through collaborative advocacy and service to member societies and their members.

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