Untargeted metabolomics identifies trimethyllysine, a TMAO-producing nutrient precursor, as a predictor of incident cardiovascular disease risk

Abstract

Using an untargeted metabolomics approach in initial (N = 99 subjects) and replication cohorts (N = 1,162), we discovered and structurally identified a plasma metabolite associated with cardiovascular disease (CVD) risks, N6,N6,N6-trimethyl-L-lysine (trimethyllysine, TML). Stable-isotope-dilution tandem mass spectrometry analyses of an independent validation cohort (N = 2,140) confirmed TML levels are independently associated with incident (3-year) major adverse cardiovascular event risks (hazards ratio [HR], 2.4; 95% CI, 1.7-3.4) and incident (5-year) mortality risk (HR, 2.9; 95% CI, 2.0-4.2). Genome-wide association studies identified several suggestive loci for TML levels, but none reached genome-wide significance; and d9(trimethyl)-TML isotope tracer studies confirmed TML can serve as a nutrient precursor for gut microbiota-dependent generation of trimethylamine (TMA) and the atherogenic metabolite trimethylamine N-oxide (TMAO). Although TML was shown to be abundant in both plant- and animal-derived foods, mouse and human fecal cultures (omnivores and vegans) showed slow conversion of TML to TMA. Furthermore, unlike chronic dietary choline, TML supplementation in mice failed to elevate plasma TMAO or heighten thrombosis potential in vivo. Thus, TML is identified as a strong predictor of incident CVD risks in subjects and to serve as a dietary precursor for gut microbiota-dependent generation of TMAO; however, TML does not appear to be a major microbial source for TMAO generation in vivo.

Diet‐Related Metabolites Associated with Cognitive Decline Revealed by Untargeted Metabolomics in a Prospective Cohort

“…Interestingly, we observed a correlation ( r = 0.44) between TML and the gut microbial metabolite of carnitine trimethylamine‐N‐oxide (TMAO), which has been linked to cardiovascular diseases . The effects of TML on health and aging are poorly documented, with the notable exception of a recent untargeted metabolomics study reporting an association of TML with increased risk of cardiovascular diseases …”

The mutual interplay of gut microbiota, diet and human disease

“…1) [62]. Metabolomic studies suggested that high TMAO concentrations are positively correlated with cardiovascular events such as death, myocardial infarction (MI) and stroke [63]. In line with these data, in Apoe-deficient mice fed a TMAO-rich diet increased macrophage foam cell formation and aortic atherosclerotic plaque development was observed [28,64].…”

The biology of ergothioneine, an antioxidant nutraceutical

“…It had been designated as a transporter of carnitine and of the (non-physiological) tetraethylammonium cation. However, in a really groundbreaking paper, Gründemann et al (130) recognised that the rates observed (using radioisotopes) were too small to be physiologically meaningful, and using a method that we would now refer to as 'untargeted metabolomics' (159)(160)(161)(162)(163)(164) , they incubated two kinds of HEK293 cells in serum. The first were normal cells, that, as with many transporters (119) , do not in fact express SLC22A4 at significant levels, while the second had been engineered to overexpress the transporter.…”