The human gut harbours trillions of microbial organisms. The overall architecture of the microbial community is remarkably stable over time within an individual and his/her family members. However, gut microbial composition and function are also profoundly influenced by dietary exposure and the local intestinal environment. Thus, the combined functions of the gut microbiome and host genotype together determine global physiological responses to varied nutrient inputs, with both dynamic and adaptive functional components from gut microbiome and host participating. Furthermore, the gut microbiome has been increasingly appreciated to play important physiological and metabolic roles in our overall health and disease.

It has long been recognised that heart failure (HF) is associated with altered intestinal function, likely as a consequence of ischaemia and/or congestion within the intestines. There is enhanced gut bacterial translocation due to impaired intestinal barrier function, as well as release and detection of heightened levels of endotoxin-like compounds within the circulation, accompanied by heightened inflammatory responses and increased indices of oxidative stress. On the other hand, metabolic derangements as a result of altered gut microbial metabolism may also influence the overall host metabolic processes. Our group has discovered that gut microbiota, via specific microbial choline trimethylamine-lyases, play an obligatory role in the generation of trimethylamine N-oxide (TMAO), a bioactive metabolite of choline or L-carnitine that contributes to cardiovascular disease pathogenesis.1 ,2 In recent studies, we further observed that patients with HF have significantly …