Impact of Micro- and Nanoplastics on Human Health
Micro- and nanoplastics, which are increasingly prevalent in the environment, routinely enter the human body through various channels, including the water we consume, the food we eat, and even the air we inhale. Recent research from the University of Rhode Island College of Pharmacy indicates that these plastic particles can infiltrate all systems of the body, including the brain, where they may accumulate and potentially trigger Alzheimer’s-like conditions.
Research Overview
Following a previous study that demonstrated the ability of microplastics to cross the blood-brain barrier—a protective filter that shields the brain from harmful substances—researcher Jaime Ross expanded her investigation to assess the implications of these plastic toxins on brain health. Her recent findings suggest that the accumulation of micro- and nanoplastics in the brain may contribute to cognitive decline and the development of Alzheimer’s disease, particularly in individuals with genetic predispositions.
Study Details
Ross’s study was recently published in the journal Environmental Research Communications and involved genetically modified mice that contained the naturally occurring gene APOE4. This variant is a significant risk factor for Alzheimer’s disease, increasing the likelihood of developing the condition by 3.5 times compared to individuals carrying the APOE3 variant.
“In these mice, similar to humans, there is no guarantee that cognitive changes will manifest. For instance, identical twins possessing the APOE4 gene may exhibit vastly different cognitive health,” Ross explained. “This emphasizes the influence of lifestyle and environmental factors. Our research is exploring various modifiable aspects related to Alzheimer’s, including diet, exercise, vitamins, and particularly, exposure to environmental toxins like microplastics.”
Methodology and Findings
To investigate the impact of microplastics, Ross and her team exposed two groups of mice—one with the APOE4 variant and another with the APOE3 variant—to micro- and nanoplastics in their drinking water over a span of three weeks. The polystyrene particles, ubiquitous in items like Styrofoam containers and plastic cups, infiltrated the mice’s organs, including the brain, as anticipated. A control group for each genetic designation was also maintained without microplastic exposure.
The mice underwent a variety of cognitive tests, beginning with an open-field test where they were observed in a chamber for 90 minutes. Typically, mice tend to remain near the walls, seeking refuge from perceived threats. However, the APOE4 mice, particularly males, exhibited increased exploratory behavior, spending more time in the open areas of the chamber, indicating a potentially altered perception of risk.
In another assessment that measured the ability to recognize novel objects, mice were placed in an environment with two distinct objects. After familiarization, one of the objects was replaced with a different shape. The female mice with APOE4 and microplastic exposure demonstrated difficulty recognizing the new object, suggesting signs of cognitive decline that may affect memory.
Conclusion and Future Research Directions
These findings raise significant concerns regarding the cognitive effects linked to micro- and nanoplastic exposure, highlighting them as critical environmental toxins. A current URI study underscores the extent of microplastic accumulation, revealing over 1,000 tons of microplastics within the top two inches of Narragansett Bay’s floor.
Ross emphasizes the necessity for continued research on this topic and advocates for better regulatory measures to address these environmental toxins. She has engaged with the U.S. Congressional delegation regarding the Microplastics Safety Act, which aims to direct the FDA to investigate the human health impacts of microplastics in food and water, particularly regarding vulnerabilities in children and potential links to chronic illnesses.
“There has been insufficient funding allocated to studying the health impacts of microplastics,” Ross noted. “Our research findings in mice resonate with real-world observations, and we seek to promote further studies on the widespread issue of micro- and nanoplastics.”
Key Health Takeaway
Micro- and nanoplastics are emerging environmental toxins with potential links to cognitive decline and Alzheimer’s disease, particularly among individuals with genetic risk factors. Continued research is essential for understanding their impact on human health and informing regulatory policies to mitigate exposure.
