Acute Eucalyptus Smoke Inhalation Sensitizes Rats to the Postprandial Effects of a High Carbohydrate Oral Load
Citation:
Martin, B., L. Thompson, Y. Kim, S. Snow, M. Schladweiler, P. Phillips, C. King, J. Richards, W. Martin, N. Coates, Ian Gilmour, U. Kodavanti, M. Hazari, AND A. Farraj. Acute Eucalyptus Smoke Inhalation Sensitizes Rats to the Postprandial Effects of a High Carbohydrate Oral Load. Annual meeting of the Society of Toxicology, Baltimore, Maryland, March 10 - 14, 2019.
Impact/Purpose:
This work demonstrates that exposure to air pollution, including from wildland fire-related sources, can modify and potentially heighten responses to even mild day-to-day inflammatory triggers. Thus, exposure may reduce the capacity of the body to compensate, and in essence tolerate, ordinary stressors of the cardiovascular system, potentially increasing cardiovascular risk. This paradigm may explain some of the reported health effects at near NAAQS exposure levels.
Description:
Previous studies have shown that air pollution exposure primes body systems to heightened responses to everyday activities that stress the cardiovascular (CV) system. The goal of this study was to investigate the impacts of a one-time exposure to eucalyptus smoke (ES) on the postprandial CV effects after a single high carbohydrate (HC) challenge, a cardiometabolic stressor long used to predict CV risk. Three-month-old male Sprague Dawley rats were exposed once (1 hr) to filtered air (FA) or ES (700 µg/m3 fine particulate matter), a key wildland fire air pollution source, generated by burning eucalyptus in a quartz tube furnace. Rats were then fasted overnight, and subsequently administered an oral gavage of either water or a HC suspension (70 kcal% from carbohydrate), mimicking a HC meal, 24 hr post-exposure. Two hours post gavage, cardiac and superior mesenteric artery function, circulating lipids and hormones, and pulmonary and systemic inflammatory markers were assessed. ES inhalation alone caused an increase in lung total protein compared to control animals. HC gavage alone caused an increase in glucose, serum interleukin (IL)-13, and keratinocyte chemoattractant (KC)/growth-regulated oncogene (KC-GRO) compared to water in both FA- and ES-exposed animals. By contrast, only ES-exposed and HC-challenged animals had an increase in serum IL-4 and IL-6 compared to FA-exposed animals that received water. Echocardiography data is currently being analyzed. In summary, exposure to a model wildfire air pollution source modifies the response to a HC challenge and suggests that exposure sensitizes the body to inflammatory responses (This abstract does not reflect EPA policy).