UC Berkeley

Cardiac dysfunction in patients with liver cirrhosis is strongly associated with increased serum bile acid concentrations. Here we show that excess bile acids decrease fatty acid oxidation in cardiomyocytes and can cause heart dysfunction, a cardiac syndrome that we term cholecardia. Farnesoid X receptor; Small Heterodimer Partner double knockout mice, a model for bile acid overload, display cardiac hypertrophy, bradycardia, and exercise intolerance. In addition, double knockout mice exhibit an impaired cardiac response to catecholamine challenge. Consistent with this decreased cardiac function, we show that elevated serum bile acids reduce cardiac fatty acid oxidation both in vivo and ex vivo. We find that increased bile acid levels suppress expression of proliferator-activated receptor-γ coactivator 1α, a key regulator of fatty acid metabolism, and that proliferator-activated receptor-γ coactivator 1α overexpression in cardiac cells was able to rescue the bile acid-mediated reduction in fatty acid oxidation genes. Importantly, intestinal bile acid sequestration with cholestyramine was sufficient to reverse the observed heart dysfunction in the double knockout mice.

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