How the presence of microplastics in the brain raises questions about cognitive health
A study from the University of Rhode Island suggests that exposure to microplastics can induce behavioral and memory changes in mice genetically predisposed to Alzheimer's, rekindling the discussion about environmental risks and neurodegeneration.
The research, published in Environmental Research Communications and reported internationally, observed clear differences between animals carrying and not carrying the APOE4 risk allele after brief but intense exposure.
The experiment administered polystyrene microplastics in drinking water for weeks and analyzed behaviors and brain biomarkers, finding plastic particles in brain tissue and signs of immune response.
The authors caution about the limitations of directly translating results from animal models to humans, although they emphasize that the data open up relevant hypotheses about the interaction between risk genes and environmental pollutants.
APOE4 and vulnerability to microplastics
The APOE4 allele, present in a significant portion of the population, is a recognized risk factor for Alzheimer's disease and, according to the researchers, modulated the mice's response to plastic exposure in the study.
In the APOE4-positive mice, behavioral changes were differentially observed by sex: males showed greater apathy in exploration tests, and females showed difficulty recognizing objects—patterns that echo human clinical profiles.
Alzheimer's disease: signs in animal models
Although the observed changes resemble early markers associated with Alzheimer's, specialists insist that the evidence in mice does not prove causality in humans and call for longitudinal studies with designs that simulate real-life exposure.
The authors also point out the need to incorporate aging and other environmental factors in future trials to evaluate the clinical relevance of the findings.
Plastic Pollution and Exposure Routes
Recent research has detected micro- and nanoplastics in human tissues, including the brain, increasing the urgency of understanding entry routes, cumulative doses, and long-term effects.
Experts propose investigating the digestive, respiratory, and olfactory pathways, and comparing particle shapes and sizes: morphology can influence internal transport and toxicity.
Brain Health: Implications and Limits of Current Knowledge
The presence of microplastics in the brain does not automatically imply irreversible damage, but it does require recognition of a potential environmental factor that could interact with genetic vulnerabilities to affect brain health.
While the scientific community develops more robust protocols, practical recommendations focus on reducing personal exposure and promoting policies that limit plastic pollution on a global scale.
