Microplastics hit the liver hard on a high-fat diet, mouse study finds

In mice, polyethylene microplastics caused much more liver damage when the animals were also on a high-fat diet, a finding that adds to concerns about how routine plastic exposure may interact with modern diets.

What happened?

At the University of Oklahoma, researchers tested polyethylene microplastics, the plastic used in items like plastic bags and milk jugs, and found far stronger signs of liver damage in mice on a high-fat diet than in mice on a standard diet.

Tae Gyu Oh, Ph.D., an oncology science professor at the OU College of Medicine, and his colleagues exposed mice to equal amounts of microplastics for eight weeks.

Some of the mice were kept on a standard diet, while others were fed a diet meant to model MASH, or metabolic dysfunction-associated steatohepatitis, a serious type of fatty liver disease.

In blood tests, mice that got microplastics while eating the high-fat diet showed liver-injury markers that rose to more than double the levels seen in mice given the same particles with a standard diet.

The researchers also used spatial transcriptomics to map the damage at the single-cell level and found distinct liver "hot spots."

Why does it matter?

The finding, published in the journal Science Advances, stands out because avoiding microplastics is becoming more difficult, and liver disease is already a significant public health issue.

"Exposure to microplastics is inevitable," Oh said. "We inhale them, ingest them and they are on our skin. … This high-resolution view helped us identify specific 'hot spots' of liver damage at the single-cell level that would have been impossible to detect using traditional approaches."

Researchers still do not fully understand how these particles affect the body, but the results suggest that diet may make the damage worse.

The team highlighted two parts of the liver's response: PPAR-alpha, a gene regulator, and Anxa2, a tissue-repair gene.

The results suggest microplastics may disrupt the liver's usual defense and repair processes, particularly when fatty liver disease is already putting the organ under strain.

Researchers are still studying how closely findings in mice translate to humans.

The study also helps explain why institutions are investing more in examining environmental contaminants alongside chronic disease rather than treating them as separate issues.

Oh explained, "By gaining such a detailed look at the liver, we were able to see specific regions where microplastic exposure triggered inflammation and altered important biological pathways. These findings provide new clues about how environmental exposures may contribute to liver disease and point to areas for future investigation."

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