Purpose of review: The mechanisms related to adverse respiratory and cardiovascular effects in populations exposed to particulate matter are under debate and different models have been used to further our understanding of the various aspects of those effects. In this review we present some studies that may give new insights into the cellular and systemic mechanisms related to particulate matter toxicity.
Recent findings: Strong epidemiological evidence is now available regarding exposure markers and health effects. This is evident in the correlation between carbon content in macrophages and decrease in lung function, an increase in the risk of chronic obstructive pulmonary disease, lung cancer and postnatal mortality. The role of outdoor temperature and a missing allele for GSTM1 and the impact of these factors on cardiovascular effects are also reported. At the experimental level, the effects of particulate matter and the interactions between different cell types, the role of toll-like receptor-2 and 4, the translocation of particles through cell monolayers and the activation of endothelial cells by particulate matter are also discussed. The role of composition is under intense debate, and different statistical analyses have been proposed.
Summary: Experimental studies on the effects of particulate matter are giving plausibility to the epidemiological findings, but the possible mechanisms of action are also becoming a hot topic.