A Perfect Storm of Pollutants: Environmental Mixtures in the Pathogenesis of Atherosclerosis.

Atherosclerosis is a complex, multifactorial disease and the leading underlying cause of cardiovascular morbidity and mortality worldwide. Beyond traditional risk factors, growing evidence highlights the critical role of environmental exposures in modulating atherogenesis. In real-world scenarios, individuals are exposed to complex mixtures of contaminants, including particulate matter, toxic metals, pesticides, polycyclic aromatic hydrocarbons, and endocrine-disrupting chemicals. These combined exposures may exert additive, synergistic or antagonistic effects, resulting in biological responses that cannot always be predicted from single-agent exposures. At the cellular and molecular level, both chemical mixtures and environmental co-exposures converge on key pathogenic pathways, including oxidative stress, endothelial dysfunction, chronic inflammation, and lipid dysregulation. These processes may favor monocyte recruitment, foam cell formation, vascular smooth muscle cell remodeling, and plaque instability. Moreover, cumulative exposures are associated with epigenetic alterations, such as dysregulation of DNA methylation and non-coding expression patterns, which may influence long-term susceptibility to atherosclerosis. This structured narrative review synthesizes evidence from 37 studies investigating the cellular and molecular mechanisms underlying the impact of environmental mixtures and multipollutant co-exposures on atherosclerosis. By integrating evidence from epidemiological, toxicological, experimental, bioinformatics and multi-omics studies, while recognizing the predominantly associative nature of the available human evidence, we highlight emerging mechanistic insights and discuss the relevance of mixture-based approaches for improving risk assessment and informing future preventive strategies.