Citation:

Harmon, M., Y. Kim, C. King, B. Martin, N. Coates, Ian Gilmour, A. Farraj, AND M. Hazari. The Effect of Enriched vs. Inadequate Housing Conditions on Biomass Smoke-induced Cardiovascular Dysfunction in Mice#. Society of Toxicology 2019 Annual Meeting, Baltimore, Maryland, March 10 - 14, 2019.

Impact/Purpose:

This work demonstrates a previously undescribed role for housing conditions as a determinant of the health effects of exposure to air pollution. Poor housing conditions, and other psycho-social factors, may increase vulnerability of subjects to the cardiopulmonary effects of air pollution exposure. These findings may spur consideration of such factors in air quality policy efforts geared towards mitigating the effects of air pollution.

Description:

Air pollution increases the risk of cardiovascular (CV) morbidity and mortality, even with short term exposures. Extrinsic factors that cause psychosocial stress may increase susceptibility to the CV effects of air pollution. Lower socioeconomic status, lack of physical activity and green spaces (i.e. urbanized areas) are associated with deleterious CV changes. Noise, extreme temperatures, and inadequate social environment lead to stress and CV changes in rodents. In addition, wildfires increasingly threaten public health as they become more widespread and occur more frequently at urban/wildland interfaces. Biomass smoke is an understudied air pollutant. We hypothesized that unenriched housing conditions (IE), as a factor of psychosocial stress, would worsen CV responses in mice exposed to biomass wood smoke, and that subsequent inclusion of environmental enrichment (EE) would mitigate these effects. Female C57BL/6 mice were divided into IE or EE housing, and after 6 weeks, mice were implanted with radiotelemeters which continuously monitored heart rate (HR), body temperature, and electrocardiogram. Two weeks later, mice were exposed to filtered air (FA) for 1 hour and 4 days later to biomass wood smoke (flaming eucalyptus; WF) for 1 hour. Mean baseline HR, 1 week prior to exposure, was significantly lower in the EE group (592.6 bpm ± 1.2) compared to the IE group (607.0 ± 1.2; p < 0.0001). During a single 1-hour exposure to biomass smoke, HR in the IE group increased earlier and was significantly elevated after 54 minutes (618.0 bpm ± 15.3) compared to the EE group (504.4 bpm ± 27.3; p = 0.001). HR during WF in the IE group was significantly elevated after 1-hour (636.9 bpm ± 24.6) compared to FA (524.1 bpm ± 22.2; p = 0.003); however, in EE conditions, HR did not significantly increase during WF. These results suggest that housing stress and EE differentially affect baseline HR and sensitivity to the CV effects of biomass smoke (This abstract does not reflect EPA policy)..

Record Details: