Influence of air pollutants on circulating inflammatory cells and microRNA expression in acute myocardial infarction

Air pollutants increase the risk and mortality of myocardial infarction (MI). The aim of this study was to assess the inflammatory changes in circulating immune cells and microRNAs in MIs related to short-term exposure to air pollutants. We studied 192 patients with acute coronary syndromes and 57 controls with stable angina. For each patient, air pollution exposure in the 24-h before admission, was collected. All patients underwent systematic circulating inflammatory cell analyses. According to PM(2.5) exposure, 31 patients were selected for microRNA analyses. STEMI patients exposed to PM(2.5) showed a reduction of CD4(+) regulatory T cells. Furthermore, in STEMI patients the exposure to PM(2.5) was associated with an increase of miR-146a-5p and miR-423-3p. In STEMI and NSTEMI patients PM(2.5) exposure was associated with an increase of miR-let-7f-5p. STEMI related to PM(2.5) short-term exposure is associated with changes involving regulatory T cells, miR-146a-5p and miR-423-3p.