Bile Acid diarrhea: prevalence, pathogenesis, and therapy

Area of Science:

• Gastroenterology
• Digestive System Physiology
• Microbiome Research

Background:

• Bile acid diarrhea (BAD) is frequently observed in patients with ileal Crohn's disease or after ileal resection.
• A significant percentage of individuals with functional diarrhea or irritable bowel syndrome with diarrhea (IBS-D) also exhibit signs of BAD.
• The prevalence of BAD is estimated to affect approximately 1% of the general population.

Purpose of the Study:

• To explore the underlying causes of bile acid diarrhea (BAD), including hormonal deficiencies and genetic factors.
• To understand the physiological mechanisms by which bile acids influence colonic function.
• To review diagnostic methods and therapeutic strategies for managing BAD.

Main Methods:

• Investigated the role of fibroblast growth factor 19 (FGF-19) deficiency in regulating bile acid (BA) synthesis.
• Examined genetic variations impacting BA enterohepatic circulation and TGR5 receptor function.
• Analyzed changes in fecal microbiome composition and primary bile acids in patients with IBS-D.

Main Results:

• Bile acids (BAs) are implicated in enhancing mucosal permeability, stimulating water and electrolyte secretion, and accelerating colonic transit.
• Elevated levels of primary BAs in stool and altered fecal microbiomes are observed in patients with IBS-D.
• Diagnostic approaches include specific tests and therapeutic trials with bile acid sequestrants.

Conclusions:

• BAD is a condition with significant prevalence, particularly in functional diarrhea and IBS-D patients.
• Understanding the role of FGF-19, genetic factors, and the TGR5 receptor is crucial for diagnosing and treating BAD.
• Management strategies include bile acid sequestrants, with FXR agonists showing therapeutic promise.