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2017 Cardiovascular Research Day Abstract Book

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Serum Levels of Dioxin-Like Pollutants Are Positively Associated With the Cardiometabolic<br />

Disease Risk Biomarker TMAO in Leaner Individuals<br />

Michael Petriello, PhD 1 • Richard Charnigo • Manjula Sunkara • Sony Soman • Marian Pavuk 2 •<br />

Linda Birnbaum 3 • Andrew Morris, PhD 4 • Bernhard Hennig 5<br />

1<strong>Cardiovascular</strong> <strong>Research</strong> Center, University of Kentucky • 2 CDC Agency for Toxic Substances and<br />

Disease Registry • 3 NCI at NIEHS • 4 <strong>Cardiovascular</strong> Medicine, University of Kentucky • 5 Superfund<br />

<strong>Research</strong> Center, University of Kentucky<br />

Postdoc<br />

Trimethylamine N-oxide (TMAO) is a diet and gut microbiota-derived metabolite that has been<br />

linked to cardiovascular disease risk in human studies and animal models. TMAO levels show wide<br />

inter and intra individual variability in humans that can likely be accounted for by multiple factors<br />

including diet, the gut microbiota, levels of the TMAO generating liver enzyme Flavin-containing<br />

monooxygenase 3 (FMO3) and kidney function. We recently found that dioxin-like (DL)<br />

environmental pollutants increased FMO3 expression to elevate circulating diet-derived TMAO in<br />

mice, suggesting that exposure to this class of pollutants might also contribute to inter-individual<br />

variability in circulating TMAO levels in humans. To begin to explore this possibility we examined<br />

the relationship between body burden of DL pollutants (reported by serum lipid concentrations)<br />

and serum TMAO levels (n=340) in the Anniston, AL cohort, which was highly exposed to<br />

polychlorinated biphenyls (PCBs). TMAO concentrations in archived serum samples from the<br />

Anniston Community Health Survey (ACHS-II) were measured, and associations of TMAO with 28<br />

indices of pollutant body burden, including total dioxins toxic equivalent (TEQ), were quantified.<br />

Twenty-three (22 after adjustment for multiple comparisons) of the 28 indices were significantly<br />

positively associated with TMAO. Multivariate modeling revealed that total dioxins TEQ was<br />

significantly associated with TMAO among females (except at high BMIs) but not among males. Our<br />

results from this cross-sectional study indicate that exposure to DL pollutants may contribute to<br />

elevated serum TMAO levels. With the observation that dioxins were only associated with TMAO in<br />

leaner individuals, we have begun to mechanistically study the relationship between dioxin<br />

exposure, FMO3/TMAO, and cardiometabolic disease by characterizing a mouse model that<br />

develops atherosclerosis but not adipose tissue expansion. We examined the effects of PCB 126 on<br />

markers of systemic inflammation and atherosclerotic lesion size. Exposed mice exhibited<br />

significantly increased plasma cytokine levels and accelerated atherosclerotic lesion formation.<br />

More work needs to be completed to determine the role of TMAO and FMO3 in these processes<br />

(Supported in part by NIEHS/NIH grant P42ES007380).<br />

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