Micro- and nanoplastics at the vascular interface: experimental insights into endothelial pathways and clinical evidence

Abstract Micro- and nanoplastics (MNPs) are increasingly recognized as environmental contaminants with potential implications for cardiovascular health. Their detection in the human circulation and vascular tissues raises the question of how circulating plastic particles interact with the vessel wall. As the primary cellular interface between the circulation and surrounding tissues, the vascular endothelium is uniquely positioned to encounter circulating MNPs. In this Review, we integrate experimental and human evidence on MNP-endothelium interactions and critically examine whether endothelial injury may provide a mechanistic link between circulating MNPs and cardiovascular disease. Experimental studies increasingly support direct effects of MNPs on endothelial homeostasis, including inflammatory and oxidative stress responses, impaired barrier integrity, and alterations in endothelial phenotype and function. Human studies, in contrast, primarily demonstrate circulating and vascular MNP burden and associations with atherosclerotic disease and cardiovascular outcomes, without yet establishing direct endothelial dysfunction or causality. Major differences between experimental exposure conditions and human internal exposure, together with analytical uncertainties in MNP detection, further complicate translation of these findings. Understanding how the endothelium functions as an interface for circulating MNPs, and to what extent it mediates their vascular effects, will be essential for defining the cardiovascular relevance of human MNP exposure.