As researchers and clinicians continue their search for new biomarkers capable of predicting cardiovascular event risk, there is optimism that the nontraditional marker trimethylamine N-oxide (TMAO), a microbial byproduct of intestinal bacteria, may serve as an accurate screening tool for predicting future risk of heart attack, stroke, and even death in persons not otherwise identified by traditional risk factors. The TMAO assay, currently available from LipoScience (Raleigh, N.C.) for research only purposes, was recently named by the Cleveland Clinic as one of its top 10 innovations for 2014. TMAO is produced when intestinal bacteria digest the nutrient phosphatidylcholine (choline) present in egg yolks, red meat, and dairy products. This metabolite is believed to directly contribute to the pathophysiology of atherosclerosis and resulting coronary artery disease. A study led by Cleveland Clinic researchers (published in the April issue of the New England Journal of Medicine) established that intestinal microbiota, when suppressed with antibiotics, produce less TMAO, and when not suppressed TMAO was tied to dietary phosphatidylcholine through the use of stable-isotope-tracer feeding studies. Additionally, the study identified the potential clinical significance of the intestinal microbiota-dependent metabolite by showing that fasting plasma TMAO levels predict the risk of future cardiovascular events independently […]