title: The complex metabolism of trimethylamine in humans: endogenous and exogenous sources.
abstract: Trimethylamine (TMA) is a tertiary amine with a characteristic fishy odour. It is synthesised from dietary constituents, including choline, L-carnitine, betaine and lecithin by the action of microbial enzymes during both healthy and diseased conditions in humans. Trimethylaminuria (TMAU) is a disease typified by its association with the characteristic fishy odour because of decreased TMA metabolism and excessive TMA excretion. Besides TMAU, a number of other diseases are associated with abnormal levels of TMA, including renal disorders, cancer, obesity, diabetes, cardiovascular diseases and neuropsychiatric disorders. Aside from its role in pathobiology, TMA is a precursor of trimethylamine-N-oxide that has been associated with an increased risk of athero-thrombogenesis. Additionally, TMA is a major air pollutant originating from vehicular exhaust, food waste and animal husbandry industry. The adverse effects of TMA need to be monitored given its ubiquitous presence in air and easy absorption through human skin. In this review, we highlight multifaceted attributes of TMA with an emphasis on its physiological, pathological and environmental impacts. We propose a clinical surveillance of human TMA levels that can fully assess its role as a potential marker of microbial dysbiosis-based diseases.
authors.affiliation: Molecular Medicine Group,International Centre for Genetic Engineering and Biotechnology,New Delhi,India.
authors.forename: Jyoti
authors.initials: J
authors.lastname: Chhibber-Goel
authors.affiliation: Molecular Medicine Group,International Centre for Genetic Engineering and Biotechnology,New Delhi,India.
authors.forename: Anamika
authors.initials: A
authors.lastname: Gaur
authors.affiliation: Molecular Medicine Group,International Centre for Genetic Engineering and Biotechnology,New Delhi,India.
authors.forename: Varsha
authors.initials: V
authors.lastname: Singhal
authors.affiliation: Cardiothoracic Sciences Centre,All India Institute of Medical Sciences,New Delhi,India.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Parakh
authors.affiliation: Cardiothoracic Sciences Centre,All India Institute of Medical Sciences,New Delhi,India.
authors.forename: Balram
authors.initials: B
authors.lastname: Bhargava
authors.affiliation: Molecular Medicine Group,International Centre for Genetic Engineering and Biotechnology,New Delhi,India.
authors.forename: Amit
authors.initials: A
authors.lastname: Sharma
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000378:metabolism; D000818:Animals; D050197:Atherosclerosis / Q000378:metabolism* / Q000473:pathology; D004032:Diet; D006801:Humans; D008661:Metabolism, Inborn Errors / Q000378:metabolism* / Q000473:pathology; D008744:Methylamines / Q000032:analysis / Q000378:metabolism / Q000652:urine*; D009369:Neoplasms / Q000378:metabolism* / Q000473:pathology; D009812:Odorants / Q000032:analysis; D051437:Renal Insufficiency / Q000378:metabolism* / Q000473:pathology; D012307:Risk Factors; D013927:Thrombosis / Q000378:metabolism* / Q000473:pathology
chemical_list: D000393:Air Pollutants; D008744:Methylamines; C005855:trimethyloxamine; C023336:trimethylamine