A systematic review of the potential neurotoxicity of micro-and nanoplastics: the known and unknown
Abstract
Background: The escalating accumulation of micro- and nanoplastics (MNPs) in the environment has raised significant concerns regarding their neurotoxic potential in vertebrates. This critical review synthesizes evidence from 234 original research articles across aquatic and terrestrial models, as well as in vitro systems, to evaluate the impacts of MNPs on the brain.
Main body: Emerging data suggest that MNPs may reach the brain via olfactory translocation or by penetrating the blood-brain barrier, potentially facilitated by biomolecular corona formation. However, distribution kinetics, long-term retention, and true internal exposure levels remain unresolved. We highlight that neurotoxic outcomes, such as oxidative stress, cholinergic dysfunction, neurotransmitter imbalances, and neuronal apoptosis, vary widely depending on particle size, shape, polymer type, exposure concentration, and host species. Nevertheless, inconsistencies across models and experimental conditions, such as mismatches between oxidative stress markers and behavioral effects or lack of dose-response relationships, hinder mechanistic clarity and translational relevance to human health. Notably, most current studies employ spherical polystyrene particles at supraphysiological concentrations, limiting ecological and clinical extrapolation. Interactions with microbial biofilms and host microbiota are largely unexplored, despite their probable role in modulating neurotoxicity via the gut-brain axis. Moreover,…
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Evidence Hub reads this as a systematic review, done in people. Its evidence level is 1 of 5 (Highest · pooled evidence). Pooled evidence from several studies sits at the top of the evidence pyramid.
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