Researchers discover new diet-toxicant interaction
An NIEHS grantee and colleagues have identified a new interaction that may link exposure to polychlorinated biphenyls (PCBs) with cardiovascular disease. Although their manufacture and use are now banned in the United States, PCBs break down slowly, so they remain in the environment for long periods of time.
Scientists are only just beginning to understand the mechanisms that connect diet, exposure to environmental pollutants, and cardiovascular risk. To study these mechanisms, the researchers whether exposure to PCBs can lead to increased levels of trimethylamine N-oxide (TMAO). TMAO is produced when the body metabolizes certain foods, especially those derived from animals. Several large studies in humans have linked high levels of circulating TMAO with an increased risk for heart disease.
The researchers conducted studies in mice and found that several types of PCBs led to increased levels of a liver enzyme that generates TMAO. In addition, feeding dietary precursors of TMAO to mice that had been exposed to PCBs increased blood levels of TMAO.
Taken together, the new findings identify environmental pollutants as a previously unknown modulator of blood TMAO levels and raise the possibility that exposure to environmental pollutants, like PCBs, may contribute to variability in TMAO levels among people.
Citation: Petriello MC, Hoffman JB, Sunkara M, Wahlang B, Perkins JT, Morris AJ, Hennig B. 2016. Dioxin-like pollutants increase hepatic flavin containing monooxygenase (FMO3) expression to promote synthesis of the pro-atherogenic nutrient biomarker trimethylamine N-oxide from dietary precursors. J Nutr Biochem 33:145-153.