Choline and butyrate beneficially modulate the gut microbiome without affecting atherosclerosis in APOE*3-Leiden.CETP mice

Background and aims: Choline has been shown to exert atherogenic effects in Apoe^−/− and Ldlr^−/− mice, related to its conversion by gut bacteria into trimethylamine (TMA) that is converted by the liver into the proinflammatory metabolite trimethylamine-N-oxide (TMAO). Since butyrate beneficially modulates the gut microbiota and has anti-inflammatory and antiatherogenic properties, the aim of the present study was to investigate whether butyrate can alleviate choline-induced atherosclerosis. To this end, we used APOE*3-Leiden.CETP mice, a well-established atherosclerosis-prone model with human-like lipoprotein metabolism. Methods: Female APOE*3-Leiden.CETP mice were fed an atherogenic diet alone or supplemented with choline, butyrate or their combination for 16 weeks. Results: Interestingly, choline protected against fat mass gain, increased the abundance of anti-inflammatory gut microbes, and increased the expression of gut microbial genes involved in TMA and TMAO degradation. Butyrate similarly attenuated fat mass gain and beneficially modulated the gut microbiome, as shown by increased abundance of anti-inflammatory and short chain fatty acid-producing microbes, and inhibited expression of gut microbial genes involved in lipopolysaccharide synthesis. Both choline and butyrate upregulated hepatic expression of flavin-containing monooxygenases, and their combination resulted in highest circulating TMAO levels. Nonetheless, choline, butyrate and their combination did not influence atherosclerosis development, and TMAO levels were not associated with atherosclerotic lesion size. Conclusions: While choline and butyrate have been reported to oppositely modulate atherosclerosis development in Apoe^−/− and Ldlr^−/− mice as related to changes in the gut microbiota, both dietary constituents did not affect atherosclerosis development while beneficially modulating the gut microbiome in APOE*3-Leiden.CETP mice.