UCLA and USC researchers co-authored a study, which appearsin the April edition of Environmental Health Perspectives, concerning humancell damage from the inhalation of ultrafine particulates, the smallest among aclass of microscopic airborne pollutants created from incomplete combustion ofgasoline.
The report is a collaborative effort among researchers atthe Southern California Particle Center & Supersite at UCLA, the DavidGeffen School of Medicine at UCLA and the Department of Environmental Engineeringat USC.
The study is among the first to report that ultrafineparticulates not only lodge deep inside the lungs, but also penetrate deep intothe mitochondria, the power source of a human cell, and they remain thereindefinitely. Over time, ultrafine particulates lodged in the mitochondriacause severe structural damage, adversely affecting cell function.
A number of past epidemiological studies have shown anassociation between ambient air particulates from automobile exhaust andadverse health outcomes, but those studies focus on particulates that measuregreater than 0.1 micrometers. The findings in the current study are consideredsignificant in this field of research because they are among the first to showa direct link between ultrafine particulates and destruction of a specificentity in a human cell.
Forthis study, researchers spent five months collecting particulates under thedirection of Constantinos Sioutas, deputy director of Southern CaliforniaParticle Center & Supersite and a professor of environmental engineering atUSC. Samples were separated into three categories: coarse, fine and ultrafine.Dr. John Froines, director of the Southern California Particle Center andSupersite, Dr. Andre Nel, professor in the UCLA Department of Medicine andinvestigator for center and Dr. Arthur Cho, professor of pharmacology at UCLAand investigator for the center, performed lab analyses to assess how the sizeand chemical composition of the particulates affect changes in the body.
Researchers agreed that while the effects of cell damagefrom exposure to ultrafine particulates are clear, the question of howultrafine particulates gain access to the mitochondria or specifically how theyinduce damage to the mitochondria remains a mystery and will require additionalresearch to answer.
The Southern California Particle Center & Supersite,which is part of the UCLA Institute of the Environment at UCLA, brings togetherscientists from leading universities nationwide to investigate the health effectsof particulate matter. Funding for the study was provided by the EPA Science ToAchieve Results program and the California Air Resources Board, with support bythe National Institute of Environmental Health Sciences.