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Chronic Waterborne Exposure to Polystyrene Microplastics Induces Kupffer Cell Polarization Imbalance and Hepatic Lipid Accumulation

The FASEB Journal 2025 2 citations ? Citation count from OpenAlex, updated daily. May differ slightly from the publisher's own count.
Ting Li, Ting Li, Zhenghong Yao, Yuxin Huang, Ran Li, Lu Zhang, Rucheng Chen, Weijia Gu

Summary

Researchers found that long-term exposure to polystyrene microplastics in drinking water caused significant fat accumulation in the livers of mice over 9 to 12 weeks. The microplastics triggered an imbalance in immune cells in the liver called Kupffer cells, shifting them toward a pro-inflammatory state. The study identifies a specific signaling pathway through which microplastics may disrupt fat metabolism and contribute to liver problems.

Polymers
Body Systems
Models

Microplastics (MPs), particles under 5 mm, are widespread environmental contaminants. Polystyrene (PS), used in many household items, degrades into polystyrene MPs (PS-MPs), which accumulate in the environment. Chronic exposure to waterborne PS-MPs was found to disrupt hepatic lipid metabolism in C57BL/6N mice through inflammatory Kupffer cell polarization and IL-17/NF-κB signaling pathways. While short-term PS-MPs exposure revealed preferential accumulation in the liver and testes, long-term exposure (9-12 weeks) induced significant increases in body fat percentage and hepatic lipid deposition independent of dietary changes. Mechanistically, chronic PS-MPs exposure promoted Kupffer cell polarization toward pro-inflammatory M1 phenotypes, accompanied by upregulated IL-17 expression and suppressed anti-inflammatory cytokines. Western blot analysis demonstrated concurrent elevation of lipid synthesis markers with reduced lipid oxidation and transport proteins. These findings established that PS-MPs accumulation drives hepatic steatosis through dual mechanisms of macrophage-mediated inflammation and impaired lipid homeostasis pathways.

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