Small extracellular vesicles: connecting early life exposure outcomes to air pollution during pregnancy to early childhood health.

Exposure to air pollution poses a serious threat to maternal and child health, particularly during critical developmental periods. Extracellular vesicles (EVs), as key mediators of intercellular communication, have emerged as a novel mechanism through which environmental exposures, including air pollutants, exert systemic effects. This review synthesizes current evidence on the role of small EVs (sEVs) in mediating the biological impacts of prenatal air pollution exposure, with a focus on their molecular profile, including the presence of signaling molecules like miRNAs and proteins, and their implications for childhood health outcomes. In this review, we explore mechanisms involving sEVs in transplacental exposure, signaling and epigenetic modifications, linking exposure to adverse developmental and health effects in early life. Furthermore, we highlight the potential of sEVs as biomarkers for exposure assessment and predictors of adverse health outcomes. Relevant studies were identified through a comprehensive literature search and systematic review of experimental and epidemiological evidence. By integrating insights from toxicology, epidemiology, and molecular biology, we identify specific needs for further research into sEVs, both as mechanistic mediators and diagnostic tools for air pollution-related health risks.