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Acrolein-Induced Increases in Blood Pressure and Heart Rate Are Coupled with Decreased Blood Oxygen Levels During Exposure in Hypertensive Rats
Citation:
Perez, C., A. Ledbetter, M. Hazari, N. Coates, A. Carll, D. Winsett, D. Costa, AND A. Farraj. Acrolein-Induced Increases in Blood Pressure and Heart Rate Are Coupled with Decreased Blood Oxygen Levels During Exposure in Hypertensive Rats. Presented at Society of Toxicology Annual meeting, March 10 - 14, 2013.
Impact/Purpose:
This study demonstrates that acrolein induced cardiovascular responses in hypertesnion are associated with reduced blood oxygen levels suggesting that the cardiovascular effects of air pollution may be mediated by hypoxia. These findings help establish biological plausibility for the epidemiological data that links exposure to air pollution to increased cardiovascular morbidity and mortality.
Description:
Exposure to air pollution increases the risk of cardiovascular morbidity and mortality, especially in individuals with pre-existing cardiovascular disease. Recent studies link exposure to air pollution with reduced blood oxygen saturation suggesting that hypoxia is a potential mechanism that mediates the adverse cardiovascular effects of air pollution. The purpose of this study was to characterize the cardiovascular effects of exposure to acrolein, a potent irritant and component of cigarette smoke and diesel exhaust and determine if acrolein exposure causes decreased blood oxygen levels. We hypothesized that hypertensive rats would be more sensitive to the adverse cardiovascular effects of acrolein and that the cardiovascular effects of acrolein would be coupled with decreased arterial blood oxygen levels during exposure. Spontaneously hypertensive (SH) and Wistar Kyoto (WKY; rats with normal blood pressure) rats implanted with biopotential radiotelemetry transmitters were exposed once for 3 hours to 3 parts per million acrolein gas or filtered air (control) in whole body plethysmograph chambers while cardiovascular and ventilatory parameters were monitored. In a separate cohort of rats, arterial blood samples were drawn before, during, and after exposure to acrolein to monitor blood oxygen saturation. We found that hypertensive, but not normal rats, had significant increases in heart rate, blood pressure, breathing frequency, and minute volume during acrolein exposure. These effects were coupled with significant decreases in arterial blood pO2 and K+ levels and significant increases in pCO2. The data suggest that hypertension predisposes to the adverse health effects of air pollution exposure and that hypoxia may have an important role in mediating these physiologic responses (This abstract does not reflect EPA policy).