ARB Research Seminar
This page updated September 12, 2013
Cardiopulmonary Health Effects of Semi-Volatile and Non-Volatile Components of PM
Michael T. Kleinman, Ph.D., Department of Medicine, University of California, Irvine
October 09, 2013
Cal EPA Headquarters, 1001 "I" Street, Sacramento, CA
Heart disease is the leading cause of death in the U.S., and exposure to particulate matter (PM) air pollution may contribute to both disease and death among populations living in polluted environments. The observed associations between PM exposure and human heart disease and death may be related to PM-induced oxidative stress and/or inflammation in the body; however, the specific mechanisms by which PM exposure worsens heart function and cardiovascular disease are not well understood.
PM is composed of solid, liquid, and semi-volatile organic components. Preliminary studies demonstrated that if most of the organic components were removed from the particles, the particles would become much less chemically reactive. We therefore tested the hypothesis that removal of organic constituents of PM would reduce the particle's ability to induce or accelerate atherosclerosis. In atherosclerosis, plaques composed of fat, cholesterol, and other components build up inside arteries and cause them to narrow over time, potentially leading to heart attack or stroke.
For this study, an atherosclerotic mouse model was used. Mice were exposed by using a particle concentrator-thermal denuder system that removed semi-volatile organic components from ambient ultrafine PM. Changes in atherosclerotic plaque formation were measured, along with heart rate, heart rate variability, and levels of lipid peroxidation. Detailed chemical and physical characterizations of thermally denuded particles were also conducted. This study showed that a novel methodology could be employed to deliver intact ultrafine ambient PM, denuded ultrafine PM, and the organic constituents alone to an atherosclerotic mouse model.
Using this methodology a major finding was that exposures to intact PM and to the isolated organic constituents of the particles accelerated the development of atherosclerotic plaques and induced decreases in heart rate variability compared to controls, as well as promoting serum lipid peroxidation. These changes were not observed when mice were exposed to denuded particles free of the organic component. These results suggest that the organic constituents of ultrafine PM, rather than the denuded particle itself, may play an important role in the progression of heart disease.
Michael T. Kleinman, Ph.D., is a Professor and Co-Director of the Air Pollution Health Effects Laboratory in the Department of Medicine at the University of California, Irvine. Prior to joining the faculty at UCI in 1982, he directed the Aerosol Exposure and Analytical Laboratory at Rancho Los Amigos Hospital in Downey, California. Dr. Kleinman's current research has focused on toxicological studies of airborne contaminants using laboratory animals. Professor Kleinman has published more than 100 articles in peer-reviewed journals dealing with the uptake and dosimetry of inhaled pollutants, cardiopulmonary and immunological responses associated with inhalation of PM2.5, health effects of acidic and non-acidic aerosols, and studies of the effects of mixtures of particles with other pollutants such as ozone, formaldehyde, sulfur dioxide, and nitrogen dioxide. Dr. Kleinman's previous studies examined cardiopulmonary effects of concentrated ambient ultrafine, fine and coarse particles using animal models of susceptible human populations. His current studies address the role of organic and inorganic constituents of air pollution mixtures in the development or exacerbation of heart disease. Dr. Kleinman has been studying the health effects of exposures to particles and gases found in ambient air for more than 30 years.
Dr. Kleinman is a consultant to the U.S. EPA Science Advisory Board, a member of the Board of Scientific Counselors for the Center of Disease Control and Prevention (CDC-ATSDR/NCEH). Professor Kleinman has recently been appointed Chairman of the State of California's Scientific Review Panel on Toxic Air Contaminants. In addition Dr. Kleinman also serves as Chairman of the Air Quality Advisory Committee, which reviews California's air quality criteria documents. Professor Kleinman holds a M.S. in Chemistry from the Polytechnic Institute of Brooklyn and a Ph.D. in Environmental Health Sciences from New York University.