Mark W. Frampton, M.D.

Each day the average person breathes about 15,000 liters, or approximately 35 pounds, of air. Gaseous and particulate contaminants in that air gain access to the body with each breath, and may have both short and long-term effects on human health. Our ongoing studies examine the effects of particle exposure on lung function, airway inflammation, and cardiovascular function. Utilizing both environmental chamber and mouthpiece exposure systems, subjects are exposed to environmentally relevant concentrations of pollutants, with or without exercise. Respiratory and systemic effects are determined using measures of lung function, examination for markers of inflammation in exhaled air, characterization of blood leukocyte and platelet responses using 3-color flow cytometry, and detailed cardiovascular monitoring.

Ultrafine particles (UFP, <100 nm diameter) may be particularly important with regard to cardiovascular effects because of their potential for evading clearance mechanisms and entering the lung interstitium and vascular space. We have demonstrated in healthy nonsmokers that inhalation of low concentrations of UFP causes changes in leukocyte expression of adhesion molecules, and reductions in the pulmonary diffusing capacity, that are consistent with altered endothelial function. The elderly and people with underlying vascular disease, such as diabetics, may be more susceptible to vascular effects of particle exposure because of impaired endothelial function and increased risk for atherosclerosis. Our studies explore the hypothesis that inhalation of ultrafine particles alters endothelial function in healthy and susceptible people. Endothelial dysfunction is critically linked to the pathogenesis of atherosclerotic vascular disease. Data from these human clinical studies of exposure to air pollutants help to elucidate the mechanisms responsible for pollutant health effects, and assist in establishing rational air quality standards.