Micro- and Nanoplastics and Pulmonary Health: The Current State of Research.

Micro- and nanoplastics are human made environmental contaminants that pose a growing concern for our health, particularly through airborne exposures. Although human autopsy studies confirm that micro- and nanoplastics are retained in lung tissue, our understanding of their short- and long-term effects on the pulmonary system is limited. We reviewed the existing literature to evaluate the effects of micro- and nanoplastics on the respiratory system and how their downstream effects may induce respiratory disease. In vivo and in vitro studies demonstrate that micro- and nanoplastics appear to have the capacity to disrupt pulmonary homeostasis through oxidative stress, immune activation, epithelial remodeling, and surfactant interference. Unfortunately, most available micro- and nanoplastics exposure studies are conducted using environmentally irrelevant plastics at high doses, which limits the accuracy and validity of conclusions regarding biological mechanisms that may contribute to chronic lung disease. To close this gap, future studies must adopt standardized, human-relevant models and realistic exposure scenarios. This includes using advanced in vitro and ex vivo platforms, and environmentally representative micro- and nanoplastics (rather than polystyrene spheres) to improve clinical relevance and support effective prevention and risk mitigation strategies.