Microplastics Linked to Cognitive Decline in Mice
Recent findings from a study at the University of Rhode Island indicate that micro- and nanoplastics are pervasive in our environment, infiltrating our food, water, and air. This research highlights their potential to accumulate in the brain and possibly exacerbate conditions akin to Alzheimer’s disease.
The study expands on previous findings that microplastics can bypass the blood-brain barrier, a protective mechanism that usually shields the brain from harmful substances. Assistant Professor Jaime Ross led research indicating that the presence of these tiny particles in the brain might be linked to memory issues and cognitive decline, especially in individuals with genetic predispositions for Alzheimer’s.
Examining Microplastic Exposure in Genetically Modified Mice
In the recent study, published in Environmental Research Communications, Ross’s team worked with mice genetically modified to possess the APOE4 gene, a known risk factor for Alzheimer’s that increases the likelihood of developing the disease significantly compared to those with the APOE3 variant.
Ross noted, “In these mice, like in humans, cognitive changes aren’t a certainty. Identical twins carrying APOE4 can have vastly different cognitive health.” This variation suggests that environmental and lifestyle factors—like diet and exposure to toxins—could significantly influence the risk of developing Alzheimer’s.
To investigate, the team exposed two groups of mice—one with APOE4 and the other with APOE3—to microplastics through their drinking water for three weeks. As expected, the polystyrene particles, common in various everyday items, were found in multiple organs, including the brain. A control group of both types did not receive any microplastic exposure.
To assess cognitive abilities, the researchers conducted an open-field test where mice were placed in a chamber to explore freely. Normally, mice tend to stay close to walls for safety, but those with APOE4 exposed to microplastics ventured into open spaces, demonstrating altered behavior.
Behavioral and Memory Impacts
Additionally, Ross tested the mice’s ability to recognize new objects. After an exploration period, the mice were returned to find one object replaced with a different one. The female APOE4 mice exposed to microplastics showed delays in recognizing the novel object, indicating possible cognitive decline.
“We noticed a shift in behavior; males explored more freely, while females struggled with recognition tasks,” Ross explained. This aligns with trends observed in human Alzheimer’s patients—the differences in apathy and memory changes seem mirrored between genders.
Addressing an Environmental and Health Crisis
The findings raise serious concerns regarding the cognitive effects of microplastic exposure, amplifying the discussion around these prominent environmental toxins. A separate study conducted in 2023 revealed alarming quantities of microplastics—over 1,000 tons—accumulated in Narragansett Bay.
Ross hopes to continue her research and advocates for greater regulatory actions. The Microplastics Safety Act, introduced to the U.S. House, aims to compel the FDA to investigate the implications of microplastics on human health, particularly concerning children’s vulnerabilities and potential links to various diseases.
“There’s been insufficient funding for studying the health impacts of microplastics,” Ross remarked, emphasizing how essential it is to explore this ongoing issue further. “What we observe in mice reflects real-world concerns.”
Reference: “Short-term exposure to polystyrene microplastics alters cognition, immune, and metabolic markers in an apolipoprotein E (APOE) genotype and sex-dependent manner” by Lauren Gaspar, Sydney Bartman, Hannah Tobias-Wallingford, Giuseppe Coppotelli and Jaime M Ross, 20 August 2025, Environmental Research Communications.
