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Emerging evidence of ozone metabolic effects and potential mechanisms
Citation:
Kodavanti, U. Emerging evidence of ozone metabolic effects and potential mechanisms. Presented at Society of Toxicology, Phoenix, AZ, March 23 - 27, 2014.
Impact/Purpose:
This symposium abstract includes the evidence of systemic metabolic alterations in rats after exposure to ozone and potential mechanisms. The key findings will be reviewed in context of metabolic syndrome predisposition.
Description:
SOT 2014 Abstract: Invitational Emerging evidence of ozone metabolic effects and potential mechanisms U.P. Kodavanti NHEERL, USEPA, Research Triangle Park, NC Recent evidence suggests that air pollutants are linked to metabolic syndrome and impact several key metabolic processes. While ozone and other respirable pollutants are unlikely to translocate systemically, neuronal pathways and/or systemic mediators released from lung injury have been implicated in metabolic impairment. Our studies provide evidence that short-term ozone exposure induces profound metabolic alterations, including acute increases in blood leptin, glucose, fatty acids, amino acids, and glucose intolerance in rodent models. These metabolic alterations are reflected in transcriptional changes in the liver, consistent with increased catabolism (i.e., increased energy expenditure and reduced lipid synthesis). Liver metabolic processes are likely coordinated with changes in adipose and muscle metabolism. Because these systemic changes are accompanied by large increases in circulating catecholamine (i.e., stress response), derangement of neurohormonally-mediated metabolic processes likely play a key role. Experiments using adrenalectomized rats confirm the importance of circulating adrenal hormones in the induction of the acute metabolic response. Collectively, data show that acute air pollution exposure results in increased energy expenditure. Conversely, the hypothermic and bradycardia responses noted in rodents exposed to air pollutants would suggest reduced energy demand. Current investigations are using systems approaches (transcriptomic, proteomic, and metabolomic) to discern how these acute metabolic responses may relate to adaptation, and when elicited in a chronic basis, may result in disease (e.g., obesity, insulin resistance, and/or type 2 diabetes). (This abstract does not reflect USEPA policy).