• Posted April 17, 2024

Mouse Study Shows Microplastics Migrating From Gut to Other Organs

Microplastics could be migrating from the digestive tract into the kidneys, livers and brains of human beings, a new mouse study suggests.

Lab mice exposed to microplastics in their drinking water wound up with the tiny plastic particles lodged in a number of different organs, researchers reported April 10 in the journal Environmental Health Perspectives.

“We could detect microplastics in certain tissues after the exposure,” said senior researcher Eliseo Castillo, an associate professor with the University of New Mexico School of Medicine. “That tells us it can cross the intestinal barrier and infiltrate into other tissues.”

Scientists estimate that people ingest five grams of microplastic particles each week, on average, about as much plastic as found in a credit card, researchers said in background notes.

“Over the past few decades, microplastics have been found in the ocean, in animals and plants, in tap water and bottled water,” Castillo said in a university news release. “They appear to be everywhere.”

To see what happens after these tiny plastic particles are eaten, Castillo and colleagues fed lab mice an amount of microplastics equivalent to what humans ingest weekly.

After a month, researchers found microplastics had found their way out of the gut and into the tissues of the liver, kidney and brain.

The accumulation in mice over such a short time has dire implications for humans, Castillo said, although animal research doesn't always pan out in humans.

Still, “these mice were exposed for four weeks,” Castillo said. “Now, think about how that equates to humans, if we're exposed from birth to old age.”

Castillo also is concerned that microplastics could be exacerbating the health problems of humans, based on prior research that has shown the particles can cause inflammation and alter cell metabolism.

Such increased inflammation could worsen gastrointestinal conditions like ulcerative colitis and Crohn’s disease, Castillo said.

The next step in research will be to see how diet affects uptake of microplastics, Castillo said.

“Everyone’s diet is different,” Castillo noted. “So, what we're going to do is give these laboratory animals a high-cholesterol/high-fat diet or high-fiber diet, and they will be either exposed or not exposed to microplastics.”

Research is also planned into how microplastics change the natural bacteria of the gut, Castillo said.

“At the end of the day, the research we are trying to do aims to find out how this is impacting gut health,” Castillo said.

“Research continues to show the importance of gut health. If you don't have a healthy gut, it affects the brain, it affects the liver and so many other tissues,” Castillo said. “So, even imagining that the microplastics are doing something in the gut, that chronic exposure could lead to systemic effects.”

More information

Yale School of Medicine has more about microplastics.

SOURCE: University of New Mexico, news release, April 15, 2024