Intestinal microbiota metabolism of l carnitine, a nutrient in red meat, promotes atherosclerosis Nature Medicine Gut Microbiota Derived TMAO: A Causal Factor Promoting Atherosclerotic Cardiovascular Disease? Characterization of TMAO productivity from carnitine challenge facilitates personalized nutrition and microbiome signatures discovery Microbiome Springer Nature Link Decoding TMAO in the Gut Organ Axis: From Biomarkers and Cell Death Me DDDT Dove Medical Press TMAO (Trimethylamine oxide) biocrates life science