In spite of more than two decades of mechanistic research, the recent statement of air pollution and Cardiovascular Diseases (CVD) from the American Heart Association remarked that at front of high degree of consistency of the epidemiology findings showing increased air pollution related CVD risk, the evidence on intermediate mechanisms remains moderate or weak. Exosomes might be the ideal candidate to mediate the effects of air pollution, since potentially they could be produced by the respiratory system, reach the systemic circulation and lead to the development of endothelial dysfunction.
The main object of our proposal is to determine whether exposure to air particles and PM-associated metals can modify exosomes (as quantity, size, membrane molecules, procoagulant activity and miRNAs content) in plasma of human subjects and to investigate whether these alterations may be linked to CVD risk factors and outcomes. The study population will include 2000 overweighed/obese subjects presenting at the Center for Obesity and Weight Control, Milan. Obese subjects have been shown to be particularly susceptible to the effects of air pollution. Exposure to air pollutants will be assessed using: a) ambient concentrations of particulate and gaseous air pollutants; b) geographical information and modelling; c) road density and traffic intensity data; d) Metals determination in urine and hair; e) Personal passive samplers (to measure PM), on a subgroup of subjects (n=200). To identify altered exosome-associated miRNAs, we will follow a two-stage, split sample study design: a discovery stage involving OpenArray miRNA expression profiling (on 1000 subjects) and a replication stage involving a real time analysis of the top 10 miRNAs. We will integrate the human study with an in-vitro model using a system made of paired cell cultures (A549 lung/ granulocytes and endothelial cells) to clarify if exosomes produced by lung/granulocytes can directly interact with endothelial cells.