From exposure to neurotoxicity induced by micro-nanoplastics with brain accumulation and cognitive decline

The pervasive presence of micro-nanoplastics (MNPs) in the human environment has raised concerns regarding their potential implications for neurological health. Once regarded as biologically inert, MNPs are now recognised as capable of penetrating the blood-brain barrier (BBB) or entering the central nervous system (CNS) through sensory neuronal pathways. Recent studies have demonstrated that MNPs can accumulate in key brain regions, such as the hippocampus and prefrontal cortex, which are critical for memory, emotion, and executive function. Animal experiments have revealed that chronic exposure to MNPs may result in cognitive deficits, behavioral disturbances, and pathological features resembling neurodegenerative diseases. The mechanisms underlying these adverse effects are likely multifaceted, involving oxidative stress, persistent neuroinflammation, synaptic dysfunction, and disturbances of the gut-brain axis. In addition to their direct neuronal effects, MNPs may also impair cerebrovascular health by promoting endothelial dysfunction, vascular calcification, and small vessel injury, further increasing the risk of cognitive decline and stroke. This review synthesizes current evidence from environmental exposure to neural accumulation, providing mechanistic insights into MNPs-induced neurotoxicity. The review also highlights critical knowledge gaps and emphasizes the urgent need for further research and public health interventions to address this emerging environmental threat.