Physicochemical properties and combined toxic effects of micro- and nanoplastics on gut and gut-organ axes

Background

Microplastics and nanoplastics are emerging foodborne contaminants that pose significant and underexplored threats to human health, particularly through their interactions with the gut-brain axis.

Scope and approach

Here we provide an in-depth exploration of the mechanistic pathways underlying the toxic effects of micro- and nanoplastics, with a focus on their impact on gut microbiota homeostasis, intestinal barrier integrity, oxidative stress, inflammation, and immune modulation. Drawing on insights from multiple model organisms, including Caenorhabditis elegans, Danio rerio, Drosophila, and rodents, we synthesize current knowledge regarding the diverse ways in which plastic particles disrupt intestinal function and induce systemic toxicity, providing valuable insights into the effects and underlying mechanisms of intestinal toxicity and gut-based external organ impairment. Plastic particles can cause mechanical damage and dysfunction in the intestinal tract and even neuronal damage by altering the intestinal flora.

Key findings and conclusions

One of the key innovations of this review is its exploration of the role of micro- and nanoplastics as vectors for dietary pollutants such as heavy metals, organic contaminants, and antibiotics, emphasizing the compounded risks of combined exposures. By integrating findings from various models, we highlight how plastic particles’ mechanical, chemical, and physical properties contribute to their toxicity and the challenges these pose to the scientific community. Importantly, we identify significant gaps in understanding, such as the long-term effects of chronic exposure to different plastic types and their potential for cumulative toxicity over time. This review also underscores the urgent need for standardized methodologies to detect and quantify plastic particles in biological systems, and calls for innovative strategies to mitigate their harmful effects through both dietary interventions and pharmaceutical approaches.