Scientists Link Microplastics and Vascular Dementia: A New Window Into Brain Health
Vascular dementia is a form of cognitive decline that occurs when the brain’s smallest blood vessels are damaged. Although it is one of the leading causes of dementia, it has not received the same intense research focus as Alzheimer’s disease, which is better known for its characteristic plaques and tangles of abnormal proteins in the brain.
Now, new work from the University of New Mexico (UNM) is highlighting a neglected side of dementia research: the role of vascular disease and even microplastics and nanoplastics in the brain.
Elaine Bearer, MD, PhD, the Harvey Family Endowed and Distinguished Professor in UNM’s Department of Pathology, has developed a framework to better define and classify different forms of vascular dementia. Her work, published in The American Journal of Pathology, proposes a structured way to identify specific processes that lead to small vessel brain injury. Beyond this, her research brings up a surprising and concerning factor that may be influencing brain health — the presence of microplastics and nanoplastics in the brain.
This discovery could reshape how researchers think about dementia, showing that the disease might not simply be a story of either Alzheimer’s or vascular decline, but rather a tangled overlap of multiple mechanisms.
What the New Research Shows
According to Bearer, vascular dementia is caused by a range of small vessel problems that can deprive brain tissue of oxygen or nutrients, leak blood components into sensitive areas, or trigger inflammation. Traditionally, doctors have focused on risk factors like hypertension, atherosclerosis, and diabetes. These conditions remain critical, but they do not tell the whole story.
Bearer’s study identified 10 distinct processes that contribute to vascular brain injury. These include issues such as reduced nutrient delivery, leakage of blood serum into the brain, inflammation, and impaired waste clearance. All of these can result in tiny strokes that, over time, damage neurons and disrupt memory and thinking.
For the research, Bearer relied on a unique resource: a repository of donated brains from New Mexicans who had died with dementia. Using specialized microscopes and staining techniques, she examined the tissues closely and discovered that many people who were diagnosed with Alzheimer’s disease also showed clear evidence of small vessel disease. This suggests that Alzheimer’s and vascular dementia are not always distinct conditions, but may often occur together.
She noted that in New Mexico, perhaps half of patients diagnosed with Alzheimer’s also had significant vascular disease in their brains. This means doctors may be overlooking an important factor when diagnosing and treating dementia.
Microplastics Enter the Picture
What makes Bearer’s work especially intriguing is the connection to microplastics and nanoplastics. These particles, which come from the breakdown of plastic products in the environment, are already known to accumulate in many human organs. Recent studies have shown they can be detected in the liver, kidney, lungs, and even the bloodstream. But the discovery of their presence in the human brain takes the concern to a whole new level.
Bearer’s investigation revealed that people with dementia had more microplastics in their brains compared to people without dementia. Not only were the particles more numerous, but their presence correlated with the type and severity of dementia symptoms. Areas with higher amounts of microplastics also showed increased levels of inflammation, suggesting that the plastics may contribute to harmful processes in the brain’s delicate environment.
She explained that the problem is that, until recently, scientists did not have the tools to visualize these particles inside brain tissue. New staining and microscopy techniques made it possible to detect them. This technological breakthrough has opened up an entirely new line of questioning about the role of environmental contaminants in brain health.
Why Vascular Dementia Has Been Overlooked
One of the reasons vascular dementia has received less attention compared to Alzheimer’s is that its underlying pathologies have not been clearly defined. Without a standardized framework, doctors and researchers have lacked the tools to properly classify and diagnose its many variations.
Bearer argues that by creating a structured approach — a way to score and categorize the different processes that damage small vessels — clinicians will be better equipped to identify and measure vascular dementia both in living patients and in autopsies.
This methodical approach could also help researchers design more effective treatments. If doctors can pinpoint whether a patient’s dementia stems from oxygen deprivation, inflammation, waste clearance issues, or a combination of these, therapies can be better targeted.
The National Institutes of Health (NIH) has already shown interest in this direction, raising the possibility of forming a consensus group of neuropathologists to establish a new classification and scoring system. Such a move could standardize research and accelerate progress across the field.
The Overlap With Alzheimer’s
For decades, Alzheimer’s disease has been studied primarily through the lens of amyloid plaques and tau tangles — abnormal protein structures that accumulate in the brain. While these features are indeed hallmark signs of Alzheimer’s, Bearer’s work suggests that in many patients, they do not exist in isolation.
The overlap between Alzheimer’s pathology and vascular disease could help explain why some patients decline faster than others, or why certain treatments have limited effectiveness. It also raises important questions about whether therapies designed solely around amyloid or tau can ever be fully effective without considering vascular health.
The Growing Concern About Plastics in the Brain
The idea that nanoplastics in the brain are a “new player” in dementia pathology is one of the most provocative aspects of Bearer’s research. Scientists are still unsure how these particles cross into the brain. One possibility is that they slip through the blood–brain barrier, the protective shield that normally keeps harmful substances out. Another is that they enter through the olfactory system, bypassing the barrier entirely by traveling through nerves in the nose.
Whatever the route, their presence in brain tissue raises urgent concerns. Not only are microplastics widespread in the environment, but human exposure is constant. Plastics are in the air, water, and food supply, making it nearly impossible to avoid them.
Bearer’s findings indicate that the levels of plastics in the brain are not only higher in people with dementia but may also be rising over time in the general population. If that is the case, the burden of microplastics could increase future rates of vascular and neurodegenerative disease.
Collaboration and Funding
Bearer’s research builds on her collaboration with Gary Rosenberg, MD, professor of Neurology and director of the UNM Alzheimer’s Disease Research Center (ADRC). Rosenberg, who has spent years studying the role of vascular disease in dementia, supported this effort through a five-year, $21.7 million NIH grant awarded in 2024.
The partnership underscores the importance of combining expertise in neurology, pathology, and innovative imaging methods to tackle complex diseases like dementia.
Why This Matters for the Future of Dementia Research
The ultimate goal of this line of research is to refine diagnosis and treatment for people with dementia. A classification system for vascular dementia, along with recognition of factors like microplastic accumulation, could make it possible to more accurately identify the underlying causes of each patient’s condition.
This has the potential to shift how clinical trials are designed, how treatments are tested, and how neurologists approach dementia care. Instead of a one-size-fits-all approach, doctors may one day be able to tailor therapies based on the exact combination of vascular and neurodegenerative factors present in the brain.
Additional Context: What Are Microplastics and Nanoplastics?
To put this discovery in perspective, it helps to understand what these particles are. Microplastics are defined as plastic fragments smaller than 5 millimeters, while nanoplastics are even tinier, typically under 1 micrometer. These particles come from the breakdown of everyday plastic products — bottles, packaging, clothing fibers, and more.
Once in the environment, they enter the food chain. Humans ingest them through drinking water, seafood, table salt, and even the air. Over the past decade, studies have confirmed that microplastics can be detected in human stool, blood, lungs, and placental tissue.
The brain is especially concerning because of its sensitivity. Unlike other organs, the brain has limited ability to repair itself. Even small disruptions in oxygen supply, inflammation, or clearance of waste can have profound impacts on cognition and memory. The idea that microplastics may contribute to these disruptions adds a serious environmental dimension to dementia research.
The Road Ahead
Much work remains to be done. Scientists need to determine whether microplastics directly cause vascular damage and dementia, or whether they are simply byproducts of other disease processes. It is also crucial to understand how these particles interact with brain cells, how they influence inflammation, and whether reducing exposure could meaningfully lower the risk of dementia.
Still, the discovery of plastics in human brains and their possible role in dementia opens a new frontier in medical research. It emphasizes the need for both environmental and medical communities to work together, because the health impacts of plastics may extend far beyond pollution or marine ecosystems — they could be influencing how our brains age.
Reference
Research Paper: Exploring Vascular Contributions to Cognitive Impairment by Elaine L. Bearer, The American Journal of Pathology, August 2025.
