Tiny plastic particles are now found across the environment, including in air, water and food. But what they do inside the human body is still largely unknown. A new laboratory study suggests that high concentrations of nanoplastics can damage kidney cells, raising questions about how sustained exposure might affect long-term kidney health.
Researchers at Flinders University exposed human kidney cells to different types and concentrations of nanoplastics under controlled laboratory conditions. The study, published in Cell Biology and Toxicology, focused on particles made from commonly used plastics, including polystyrene, polyethylene and poly(methyl methacrylate).
At lower concentrations, the nanoplastics did not cause immediate toxicity. But when exposure levels increased, researchers observed changes in cell shape, survival and regulation. According to the authors, these disruptions suggest that higher nanoplastic burdens could interfere with the kidney’s ability to maintain healthy cell function.
The effects were not uniform. The degree of cellular disruption depended on particle size, concentration and polymer type. Some combinations triggered measurable changes even at relatively lower doses, while others showed effects only at higher concentrations. This variability highlights the complexity of assessing potential health risks from nanoplastics, the researchers noted.
Because the kidneys play a central role in filtering blood and removing waste, sustained damage to kidney cells could theoretically impair filtration efficiency over time. The authors caution, however, that their findings are based on in vitro experiments, not studies in people or animals. The research does not establish how much nanoplastic exposure occurs in daily life or whether typical environmental exposures reach levels shown to harm cells in the lab.
The study adds to a growing body of research exploring how microscopic plastic particles interact with human tissues. While microplastics are generally defined as particles smaller than 5 millimeters, nanoplastics are far smaller and may behave differently in biological systems due to their size and surface properties.
The researchers emphasize that additional long-term studies are needed to understand how nanoplastics move through the body, whether they accumulate in organs and how real-world exposure compares with laboratory conditions. They also point to the need to examine potential downstream effects, including DNA damage and broader impacts on organ function.
Kidney disease already affects an estimated 1 in 7 adults in Australia, often driven by conditions such as diabetes and high blood pressure. While the new findings do not suggest nanoplastics are a known cause of kidney disease, they highlight an emerging area of environmental health research that warrants closer investigation.
For now, experts say the results should be viewed as an early warning signal rather than evidence of direct harm. The study helps clarify how nanoplastics can interact with kidney cells under extreme conditions, but it does not yet answer how those findings translate to everyday exposure from food, water or the environment.
This research was supported by the Australian Research Council Future Fellowship, the Flinders Foundation and the Flinders Medical Centre Renal Research Fund.