Alteration of cardiac function in ApoE−/− mice by subchronic urban and regional inhalation exposure to concentrated ambient PM2.5

Abstract

Ambient PM2.5 (particulate matter with an aerodynamic diameters of less than 2.5 μm) is associated with alterations in the autonomic nervous system and cardiac function, but there are significant response variations. The authors simultaneously studied the effects of concentrated PM2.5 (CAPs) in Sterling Forest (SF; dominated by long-range transported PM) and at the Mount Sinai School of Medicine (MS; rich in Ni and elemental/organic carbon [EC/OC]) in Manhattan, NY. ApoE−/− mice (n = 8/group) were exposed to filtered air or CAPs (average 133 and 123 μg/m3 in SF and MS, respectively) for 6 h/day, 5 days/week for 6 months. Electrocardiogram (ECG) tracings were monitored using telemetry. At MS, current day CAPs mass was negatively associated with short-term changes in heart rate (HR), and positively with HR variability (HRV). At SF, CAPs mass was positively associated with HR, and negatively with HRV. At MS, HR and HRV changes were associated with PM2.5 components associated with redisual oil combustion > long-range transport > traffic > FeMn > incineration > soil, and fireworks had no associations. At SF, HR and HRV were associated with long-range transport > Ni refinery > soil > residual oil combustion/traffic. At both sites, there were cardiac function associations with PM2.5, but not EC. At MS, there were associations with Ni and P, whereas at SF, they were with a mixture of long-range transported PM, crustal material, and combustion products. Thus subchronic CAPs exposures at locations with different particle compositions produced different effects on cardiac function in ApoE−/− mice.