Micro and Nano-Plastics in coronary blood and air pollution exposure across the spectrum of coronary artery disease

Background Micro- and nanoplastics (MNPs) are ubiquitous environmental pollutants. Evidence is increasing that they accumulate in human tissues following exposure and are emerging as a risk factor for health. Nonetheless, current knowledge about the burden of MNPs in the coronary circulation across the spectrum of coronary artery disease (CAD), from the acute to the chronic setting, remains limited. Moreover, the association between MNPs, air pollution exposure, and biological pathways underlying inflammation and clinical presentation of CAD has still to be investigated. Purpose To evaluate the burden (presence, concentration and type) of MNPs in the coronary blood of patients undergoing invasive coronary angiography for suspected CAD, stratified according to the clinical presentation into: 1) patients presenting with ST-segment elevation myocardial infarction (STEMI); 2) patients with chronic coronary syndromes (CCS); 3) patients with angiographically normal coronary arteries (control group). We explored associations among coronary burden of MNPs, air pollution exposure and inflammatory biomarkers across the three study groups. Methods Cross-sectional study, including 61 consecutive patients undergoing coronary angiography for suspected CAD, stratified into: STEMI (n=19), CCS (n=20) and controls with normal coronary arteries (n=22). MNPs were quantified in coronary and peripheral blood using pyrolysis-gas chromatography-mass spectrometry and laser direct infrared spectroscopy. Air pollution exposure data were collected on the day of the invasive procedure (acute exposure) and over the preceding two years (chronic exposure). Results MNPs were detected significantly more frequently in STEMI patients (84.2%) than in CCS (40%) and controls (31.8%) (p=0.002), with higher concentration and greater polymer diversity [median of 3 polymers (IQR: 2–4), p<0.001]. Polyethylene was the predominant polymer (97%). The same polymers were consistently identified in peripheral and coronary blood samples from individual patients, with the highest concentrations in coronary blood (p<0.001). STEMI patients showed higher levels of IL-6 and TNF-α (p<0.006) and were exposed to higher levels of PM2.5 (p<0.012). MNP detection was more frequent among smokers and patients exposed to PM2.5>15 µg/m³ (p=0.006), with all patients presenting both factors showing detectable MNPs (p<0.001). In multivariable analysis, smoking history emerged as the only independent predictor of MNP presence (OR 5.69, 95%CI 1.33-26.63, p=0.023). Conclusions STEMI patients exhibited a greater burden of MNPs in coronary blood than CCS and controls. MNPs detection frequently co-occurred with elevated inflammatory biomarkers, greater PM2.5 exposure, and smoking, suggesting a potential association between environmental exposure and CAD.