Particulate matter inhalation impairs coronary microvascular reactivity.
LeBlanc-AJ; Hu-Y; Muller-Delp-J; Chen-BT; Frazer-D; Castranova-V; Nurkiewicz-TR
25th Conference of the European Society for Microcirculation, Budapest, Hungary, August 26-29, 2008. Bologna, Italy: Medimond S. r. l., 2008 Aug; :13-17
We have recently shown that systemic microvascular function is impaired after inhalation exposure to fine and ultrafine particulate matter (PM). Studies have shown that exposure to airborne particle pollution increases the risk of ischemic cardiovascular events. However, it remains unclear how the coronary microcirculation contributes to such insults. We tested the hypothesis that microvascular reactivity is impaired after PM exposure in rat coronary arterioles. Rats were exposed to filtered air (control), fine PM, or ultrafine PM via inhalation at concentrations relevant to ambient air pollution (4-90 [ ]g measured pulmonary deposition). Coronary arterioles were subsequently isolated and responses to flow (FID), acetylcholine (ACh), endothelin and dea-NONO-ate were assessed. Exposure to either fine or ultrafine PM significantly impaired FID, but neither group displayed an altered response to ACh. Interestingly, vascular smooth muscle nitric oxide (NO) sensitivity (dea- NONO-ate) was decreased by exposure to ultrafine PM, but not fine PM. Furthermore, ultrafine PM exposure diminished vasoconstrictor responses to endothelin, whereas fine PM exposure had no effect on endothelin reactivity. These results suggest that ultrafine PM exposure causes significantly more microvascular dysfunction than fine PM. It is probable that such disturbances in coronary microvascular function contribute to the cardiac events associated with particle pollution exposure.
Particle-aerodynamics; Particulate-dust; Particulates; Laboratory-animals; Laboratory-testing; Cardiopulmonary-system-disorders; Cardiovascular-function; Cardiovascular-function-tests; Cardiovascular-system; Cardiovascular-system-disorders; Inhalation-studies; Respirable-dust; Risk-factors; Reaction-rates; Nanotechnology
25th Conference of the European Society for Microcirculation, Budapest, Hungary, August 26-29, 2008