The Impact of PM2.5 on Platelet Activity and Cardiovascular Health
Introduction
Fine particulate matter (PM2.5), comprising particles with a diameter of 2.5 micrometers or less, is a significant air pollutant known to penetrate deep into the respiratory tract and enter the bloodstream. Chronic exposure to PM2.5 has been linked to various adverse health outcomes, particularly affecting cardiovascular health. Emerging research indicates that PM2.5 exposure may influence platelet activity, thereby contributing to cardiovascular diseases.
How PM2.5 Affects Platelets:
Increased levels of inflammatory cytokines like IL-6 and TNF-α from PM2.5 exposure can enhance platelet activation.
Inflammation and Oxidative Stress:
PM2.5 exposure induces systemic inflammation and oxidative stress, which can activate platelets and promote their aggregation.
Pro-thrombotic Effects:
Activated platelets can contribute to blood clot formation, increasing the risk of thrombosis, which is a common underlying mechanism for heart attacks and strokes.
Altered Platelet Count and Function:
Some studies have reported changes in platelet count (either increased or decreased) and altered platelet function in individuals exposed to high levels of PM2.5.
Endothelial Dysfunction:
PM2.5 exposure can damage the endothelial cells lining blood vessels, which in turn promotes platelet adhesion and activation.
Inflammatory Cytokine Release:
Increased levels of inflammatory cytokines like IL-6 and TNF-α from PM2.5 exposure can enhance platelet activation.
The activation and aggregation of platelets due to PM2.5 exposure have significant health implications:
Multiple studies have found that short-term and long-term exposure to PM2.5 is associated with increased platelet aggregation, higher mean platelet volume (MPV), and elevated levels of platelet activation markers (e.g., P-selectin).
Increased Thrombosis Risk: Enhanced platelet activity can lead to the formation of blood clots, increasing the risk of thrombosis, heart attacks, and strokes. from the study : Long-term exposure to PM2.5 and cardiovascular disease incidence and mortality in an Eastern Mediterranean country :The cohort comprised 3081 participants over 35 years old who were free of CVDs. Mean three-year PM2·5 exposure for the cohort was measured at 45.28 μg/m3, ranging from 20.01 to 69.80 μg/m3. The median time period for conducting necessary follow-ups was 12.3 years for the whole population. In well-adjusted models, 10 μg/m3 increase in PM2.5 corresponded to a 3% increase in the incidence rate of CVDs [0.95 CI = 1.016, 1.036] but No consistent association was observed between PM2.5 concentration and fatal CVD (fatal AMI, fatal stroke, SCD (Sudden Cardiac Death)) and all-cause mortality.
Increase Platelet production :
A study involving 362,396 Taiwanese adults found that each 10 μg/m³ increase in the 2-year average PM2.5 concentration was associated with a 0.42% increase in platelet counts in men and a 0.49% increase in women. This suggests that long-term exposure to PM2.5 may enhance blood coagulability.
Cardiovascular Disease Incidence: Long-term exposure to PM2.5 has been associated with higher rates of cardiovascular diseases, partly due to its effect on platelet activation.
reference :
- https://ehjournal.biomedcentral.com/articles/10.1186/s12940-021-00797-w
- https://pubmed.ncbi.nlm.nih.gov/29753251/