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  • Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis.

Intestinal microbiota metabolism of L-carnitine, a nutrient in red meat, promotes atherosclerosis.

Nature medicine (2013-04-09)
Robert A Koeth, Zeneng Wang, Bruce S Levison, Jennifer A Buffa, Elin Org, Brendan T Sheehy, Earl B Britt, Xiaoming Fu, Yuping Wu, Lin Li, Jonathan D Smith, Joseph A DiDonato, Jun Chen, Hongzhe Li, Gary D Wu, James D Lewis, Manya Warrier, J Mark Brown, Ronald M Krauss, W H Wilson Tang, Frederic D Bushman, Aldons J Lusis, Stanley L Hazen
ABSTRACT

Intestinal microbiota metabolism of choline and phosphatidylcholine produces trimethylamine (TMA), which is further metabolized to a proatherogenic species, trimethylamine-N-oxide (TMAO). We demonstrate here that metabolism by intestinal microbiota of dietary L-carnitine, a trimethylamine abundant in red meat, also produces TMAO and accelerates atherosclerosis in mice. Omnivorous human subjects produced more TMAO than did vegans or vegetarians following ingestion of L-carnitine through a microbiota-dependent mechanism. The presence of specific bacterial taxa in human feces was associated with both plasma TMAO concentration and dietary status. Plasma L-carnitine levels in subjects undergoing cardiac evaluation (n = 2,595) predicted increased risks for both prevalent cardiovascular disease (CVD) and incident major adverse cardiac events (myocardial infarction, stroke or death), but only among subjects with concurrently high TMAO levels. Chronic dietary L-carnitine supplementation in mice altered cecal microbial composition, markedly enhanced synthesis of TMA and TMAO, and increased atherosclerosis, but this did not occur if intestinal microbiota was concurrently suppressed. In mice with an intact intestinal microbiota, dietary supplementation with TMAO or either carnitine or choline reduced in vivo reverse cholesterol transport. Intestinal microbiota may thus contribute to the well-established link between high levels of red meat consumption and CVD risk.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Desmosterol, ≥84% (GC)
Levocarnitine, European Pharmacopoeia (EP) Reference Standard
Supelco
Choline chloride, Pharmaceutical Secondary Standard; Certified Reference Material
Sigma-Aldrich
Trimethylamine N-oxide, 95%
Sigma-Aldrich
Choline chloride, BioUltra, ≥99.0% (AT)
Sigma-Aldrich
Choline chloride, BioReagent, suitable for cell culture, suitable for insect cell culture, ≥98%
Sigma-Aldrich
L-Carnitine inner salt, synthetic, ≥98%
Sigma-Aldrich
Choline chloride, ≥98%
Sigma-Aldrich
Choline chloride, ≥99%
Sigma-Aldrich
Propionyl-L-carnitine, ≥94.0% (HPLC)