New evidence links microplastics to degenerative disease

By HPN Staff

Microplastics — tiny particles that are nearly ubiquitous in the modern world — trigger Alzheimer’s-like symptoms in mice with a genetic marker for the disease, according to a new study.

The findings are one more cause for concern in a growing field of research that has identified microplastics in most human organs, including the brain.

This latest study, from a team at the University of Rhode Island, found different impacts in mice of different sexes that, for three weeks, were given water laced with plastic particles. Male mice seemed more apathetic after exposure, the researchers said, and the female mice more forgetful.

“Interestingly, these sex-dependent differences strongly relate to human clinical symptoms of [Alzheimer’s Disease], with men more often presenting with symptoms such as apathy and impaired motor control, and women often presenting with symptoms related to memory loss,” the study states.

Why it matters

Alzheimer’s, a poorly understood form of dementia, is a leading cause of death, particularly for people over 65. There is no known cure.

Cases can be hard to predict, but there are known risk factors, including a genetic marker called APOE4.

About 25% of people have the APOE4 gene, and they’re 3.5 times more likely to develop Alzheimer’s than those with the most common gene variant, APOE3, according to The Washington Post.

How APOE4 is involved is unclear, but “it is clear that the presence of APOE4 alone is not sufficient to cause AD, and there must be other contributing factors,” researchers in the Rhode Island study wrote.

Heavy metals and pesticides have been linked to Alzheimer’s, but there’s growing evidence that nano and microplastics (NMPs), which are less than 1 micrometer and 5 millimeters in size, respectively, play a role.

The Rhode Island study found that exposure to these plastics, which scrape off from plastic food containers and other plastic items, “can alter cognition and memory.” They used mice with the APOE4 genetic marker, running them through mazes and other tests, and found that those mice had problems that mice with the APOE3 marker did not.

A previous study by another team identified microplastics in human brains and said the amount of plastic in those brains was significantly higher in people who died with dementia.

The bigger picture

It was just a few years ago that plastic was discovered in human blood, according to The Post, so this is a new field of study.

But already scientists have found that NMPs can:

• Boost inflammation
• Alter cognition
• Impact reproduction
• And impact behavior

“NMPs have also been shown to interact with every system of the body,” scientists in the Rhode Island study said.

Additional details

Many things remain unclear, including how APOE4 may interact with plastic molecules and other pollutants.

The Washington Post, quoting University of New Mexico toxicology professor Matthew Campen, noted APOE4 affects how proteins transfer fat and other materials around the body.

 “What if APOE4 is just shuttling more plastic from the mouth into the brain?” Campen said. “Nobody’s really looked at this.”