Untargeted metabolomics identifies trimethyllysine, a TMAO-producing nutrient precursor, as a predictor of incident cardiovascular disease risk
Xinmin S. Li, Zeneng Wang, Tomas Cajka, Jennifer A. Buffa, Ina Nemet, Alex G. Hurd, Xiaodong Gu, Sarah M. Skye, Adam B. Roberts, Yuping Wu, Lin Li, Christopher J. Shahen, Matthew A. Wagner, Jaana A. Hartiala, Robert L. Kerby, Kymberleigh A. Romano, Yi Han, Slayman Obeid, Thomas F. Lüscher, Hooman Allayee, Federico E. Rey, Joseph A. DiDonato, Oliver Fiehn, W.H. Wilson Tang, Stanley L. Hazen
Xinmin S. Li, Zeneng Wang, Tomas Cajka, Jennifer A. Buffa, Ina Nemet, Alex G. Hurd, Xiaodong Gu, Sarah M. Skye, Adam B. Roberts, Yuping Wu, Lin Li, Christopher J. Shahen, Matthew A. Wagner, Jaana A. Hartiala, Robert L. Kerby, Kymberleigh A. Romano, Yi Han, Slayman Obeid, Thomas F. Lüscher, Hooman Allayee, Federico E. Rey, Joseph A. DiDonato, Oliver Fiehn, W.H. Wilson Tang, Stanley L. Hazen
View: Text | PDF
Research Article Cardiology Vascular biology

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.

Authors

Xinmin S. Li, Zeneng Wang, Tomas Cajka, Jennifer A. Buffa, Ina Nemet, Alex G. Hurd, Xiaodong Gu, Sarah M. Skye, Adam B. Roberts, Yuping Wu, Lin Li, Christopher J. Shahen, Matthew A. Wagner, Jaana A. Hartiala, Robert L. Kerby, Kymberleigh A. Romano, Yi Han, Slayman Obeid, Thomas F. Lüscher, Hooman Allayee, Federico E. Rey, Joseph A. DiDonato, Oliver Fiehn, W.H. Wilson Tang, Stanley L. Hazen

×

Figure 2

Stable-isotope-dilution LC-MS/MS analyses verify systemic levels of TML are associated with incident cardiovascular disease risks independent of TMAO.

Options: View larger image (or click on image) Download as PowerPoint
Stable-isotope-dilution LC-MS/MS analyses verify systemic levels of TML ...
Kaplan-Meier estimates and 3-year risks (HR [95% CI]) for (A) major adverse cardiac events (MACE, including myocardial infarction, stroke or death); and (B) all-cause mortality (5 years) ranked by trimethyllysine (TML) quartiles in the validation cohort (N = 2,140). (C) Forest plots indicate the HR (95% CI) for incident (3-year) risks for MACE and all-cause mortality (5-year) according to TML quartiles. HR (unadjusted, open circles) and multivariable Cox model 1 adjusted (filled black circles; adjusted for age, sex, high-density lipoprotein [HDL], low-density lipoprotein [LDL], smoking, diabetes mellitus, hypertension, C-reactive protein level), or model 2 adjusted (filled red squares, adjusted for model 1 plus trimethylamine N-oxide [TMAO]). The 5%–95% confidence interval is indicated by line length. The analyses were performed using R 3.4.1. HR, hazard ratio.