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BIOAVAILABLE AIR PARTICULATE POLLUTION CONSTITUENTS DIRECTLY ALTER CARDIOVASCULAR FUNCTION EX VIVO
Citation:
Dreher, K L., E. Murphy, S. Gabel, S. Kelly, S. Proctor, AND J. Russell. BIOAVAILABLE AIR PARTICULATE POLLUTION CONSTITUENTS DIRECTLY ALTER CARDIOVASCULAR FUNCTION EX VIVO. Presented at American Lung Association and American Thoracic Society International Meeting, Orlando, Florida, May 21-26, 2004.
Description:
Epidemiological studies have reported associations between particulate air pollution exposure and cardiovascular (CV) effects within susceptible individuals. Particle characteristics and biological mechanisms responsible for these observations are not known. We examined whether soluble constituents derived from oil combustion directly affect cardiovascular function ex vivo. Langendorff perfused rat hearts were exposed to a particle-free leachate (L) of residual oil fly ash (ROFA). ROFA-L exposure produced a dose dependent decrease in flow rate and left ventricular developed pressure but increased arrhythmia frequency. Alterations in ex vivo cardiac function were reproduced by a surrogate metal mixture and inhibited by antioxidant treatment. The ability of ROFA-L to alter vascular function in arteries taken from healthy and type 2 diabetic rats was examined. Aortic ring contractile force was measured following exposure to various doses of a ROFA-L and phenylepherine (PE). ROFA-L produced a dose dependent increase in PE-mediated contractility in both healthy and diabetic aortae. At low ROFA-L doses diabetic aortae displayed a greater PE-induced contractile response when compared to healthy aortae. A strong ROFA-L induced contractile response was observed only in diabetic aortae following the initial ROFA-L exposure with subsequent PE stimulation. Acetylcholine-mediated vascular relaxation was inhibited to a greater extent in diabetic aortae when compared to healthy aortae following ROFA-L exposure. These results provide mechanistic insight into alterations in CV function by oil combustion particles by demonstrating that: 1) bioavailable constituents can act directly to impair CV function; 2) exposure history and disease status maybe critical in modulating vascular functional responses; and 3) aortae from Type 2 diabetic rats were more sensitive to alterations in vascular function. (This abstract does not reflect EPA Policy)