Microplastics block blood flow in the brain, a mouse study reveals

For the first time, scientists tracked the movement of microplastics through the bodies of mice in real time¹. Tiny plastic particles are ingested by immune cells, travel through the bloodstream and eventually become lodged in blood vessels in the brain. It’s not clear whether such obstacles occur in humans, the researchers say, but they appear to affect movement in mice.

Microplastics are stains plasticless than 5 millimeters in length, which can be found everywherefrom the deep ocean to the Antarctic ice. They are found in the air we breathe, the water we drink and the food we eat. They can even enter our bloodstream directly through plastic medical devices.

Studies show that microplastics and smaller nanoplastics have made their way into the human brain, liver and kidneys, but researchers are only beginning to understand what happens to these plastic intruders and their effect on human health. One study last year, for example, found that people with micro- and nano-plastics in fatty deposits in a major artery were more likely to experience heart attackstroke or death².

‘car accident’

In the latest study, published in Scientific progress today, Haipeng Huang, a biomedical researcher at Peking University in Beijing, and his colleagues wanted to better understand how microplastics affect the brain. They used a fluorescence imaging technique called miniature two-photon microscopy to observe what was happening in the mouse brain through a transparent window surgically implanted in the animal’s skull.

The imaging technique can track microplastics as they move through the bloodstream, says Eliane El Hayek, an environmental health researcher at the University of New Mexico in Albuquerque. “It’s very interesting and very helpful.”

The researchers gave the mice water laced with fluorescent polystyrene beads, a popular product used to make devices, packaging and even toys. About three hours later, fluorescent cells appeared. Further investigation showed that immune cells known as neutrophils and phagocytes engulfed the bright plastic blobs. Some of these cells probably became trapped in the tight turns of tiny blood vessels in an area of ​​the brain called the cortex. Multiple cells in the plastic packaging would sometimes clump together — “like a collision in blood vessels,” Huang says. Some obstacles eventually disappeared, but others remained during the four-week observation period.

When the researchers injected the plastic beads intravenously into the mice, they observed the glowing cells within minutes. Smaller particles resulted in fewer obstacles.

Worn debris