Trimethylamine N-oxide (TMAO) is a metabolite of choline, phosphatidylcholine, and L-carnitine .1 It is formed by gut microbiota-mediated metabolism of choline, phosphatidylcholine, and L-carnitine to TMA followed by oxidation of TMA by flavin-containing monooxygenase 3 (FMO3) in the liver.1,2,3 Dietary administration of TMAO (0.12% w/w) increases renal tubulointerstitial fibrosis, collagen deposition, and Smad3 phosphorylation in mice and increases aortic lesion area in atherosclerosis-prone ApoE-/- mice.1,4 Plasma levels of TMAO are elevated in patients with chronic kidney disease and decreased in patients with active, compared with inactive, ulcerative colitis.1,2 Elevated plasma levels of TMAO are associated with increased risk of cardiovascular disease.4
1.Tang, W.H.W., Wang, Z., Kennedy, D.J., et al.Gut microbiota-dependent trimethylamine N-oxide (TMAO) pathway contributes to both development of renal insufficiency and mortality risk in chronic kidney diseaseCirc. Res.116(3)448-455(2015) 2.Wilson, A., Teft, W.A., Morse, B.L., et al.Trimethylamine-N-oxide: A novel biomarker for the identification of inflammatory bowel diseaseDig. Dis. Sci.60(12)3620-3630(2015) 3.Zhang, L.S., and Davies, S.S.Microbial metabolism of dietary components to bioactive metabolites: Opportunities for new therapeutic interventionsGenome Med.8(1)46(2016) 4.Wang, Z., Klipfell, E., Bennett, B.J., et al.Gut flora metabolism of phosphatidylcholine promotes cardiovascular diseaseNature472(7341)57-63(2011)