In Vivo Tissue Distribution of Microplastics and the Systemic Metabolic Changes After Gastrointestinal Exposure in Mice

Marcus M. Garcia, Aaron S. Romero, Seth D. Merkley, Jewel L. Meyer-Hagen, Charles Forbes, Matthew J. Campen, Julie G. In, and Eliseo F. Castillo Microplastics (MP) are slated to be the next environmental threat to humans. It is estimated humans consume approximately 5 grams of MP per week. To date, the systemic impact of MP ingestion on metabolic pathways in systemic organs have not been studied utilizing environmentally relevant doses and mixtures. To investigate the impact of ingested MPs on target metabolic pathways, mice were exposed to either polystyrene (5 μm) microspheres or a mixture of MPs consisting of polystyrene (5 μm), polyethylene (1-4 μm), and the biodegradability and biocompatible plastic, poly-(lactic-co-glycolic acid) (5 μm). Exposures were performed twice a week for four weeks at a dose of either 0, 2, or 4 mg/week via oral gastric gavage. Our findings demonstrate that, in mice, ingested MPs can pass through the gut barrier and accumulate in distant tissues. Additionally, we report on the metabolic changes that occur in the colon, liver and brain which show differential responses that are dependent on dose and type of MPs exposure. This study provides critical insight into the pervasive issues of plastic pollution and highlights dose-dependent and polymer type specific metabolic changes in the colon, liver and brain caused by MPs exposure. NIH/NIEHS 1R01 ES032037-01A1. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.