Reacción a "A study claims that patients who have suffered a heart attack have higher levels of micro- and nanoplastics in their blood"

The article evaluates the presence of micro- and nanoplastics (MNPs) in the coronary and peripheral blood of 61 patients. The results revealed a significantly higher quantity of synthetic polymers in patients suffering from acute myocardial infarction in comparison with patients with normal coronary arteries. The authors observed that higher plastic detection correlates with elevated levels of inflammatory biomarkers, suggesting a direct relationship between MNPs, smoking, and fine particulate matter (PM2.5) pollution as drivers for coronary artery disease

Linking the exposome to cardiovascular health via in vivo detection is a truly pioneering outcome, but the study presents significant methodological weaknesses that compromise its conclusions regarding the relationship between plastics and cardiovascular health. First, the sample size is too small (61 patients, only 31 with detectable MNPs) to reliably support a multivariable regression analysis. The paper omits ingestion as a primary route for MNP internalization, which is contrary to the current scientific consensus. Additionally, relying on monitoring stations near the patients' residences implies that regional outdoor data accurately reflects individual exposure, ignoring indoor air pollution, occupational hazards, and other factors. Finally, the link to smoking is unclear, as cigarette filters are primarily made of cellulose acetate, which is a polymer not found in this study.

Other methodological issues include gender and comorbidity differences across the cohorts, but, more importantly, the use of the Py-GC/MS technique. This methodology is known to give rise to false positives because the thermal degradation of lipids produces volatile compounds identical to those of plastics.

This issue is particularly critical for polyethylene, which accounts for 97% of the findings, as using 1-hexadecene as the sole indicator ignores the fact that this compound is also formed when pyrolyzing biological matrices. The omission of pyrograms and specific ions further undermines the credibility of the quantification. It is important to note that the measured concentrations, reaching up to 2.5 mg/L, are extraordinarily high, falling within the upper range of levels detected in wastewater treatment plant influents. This strongly suggests a potential artifact derived from medical materials and the release of plaque lipids during the aspiration procedure, a possibility the article fails to address.

Finally, while the need to reduce plastic exposure is obvious under the precautionary principle and the approach of in vivo analyses is appealing, the study suffers from major methodological gaps and conclusions that are insufficiently supported by clear evidence.