The association of bile acid excretion and atherosclerotic coronary artery disease

Abstract

Background: Excess cholesterol is usually eliminated from the body by conversion to bile acids excreted in feces as bile salts. The excretion of large amounts of bile protects against atherosclerosis, while diminished excretion may lead to coronary artery disease (CAD). Objective: To investigate a relationship between CAD and bile acid excretion. Methods: Bile acid excretion was compared between 36 patients with proven CAD and 37 CAD-free individuals (controls). The groups were comparable for demographics and selected risk factors. All subjects received a 4-day standard diet that included ∼500 mg of cholesterol. Fecal bile acids from 24-hour stool collections were measured by gas liquid chromatography. Results: CAD patients excreted lower amounts of total bile acids (358 ± 156 mg) than controls (617 ± 293 mg; p < 0.01) and less deoxycholic acid (188.29 ± 98.12 mg versus 325.96 ± 198.57 mg; p < 0.0001) and less lithocholic acid (115.43 ± 71.89 mg versus 197.27 ± 126.87 mg; p < 0.01). Advanced age, male gender, left ventricular ejection fraction and total bile acid levels were significant independent factors that predicted CAD ( p < 0.05). Mortality, CAD and cerebrovascular accident development rates were significantly lower for the controls at the 13-year follow up. Conclusion: CAD patients have significantly decreased bile acid excretion levels than non-CAD patients. An impaired ability to excrete cholesterol may be an additional risk factor for CAD development.