Published in Environmental Science & Technology on May 30, 2024, the study demonstrates for the first time that repeated low-level exposure to nanoplastics made from polystyrene causes significant damage to mitochondria, the cell’s energy centers, and suppresses cell differentiation under prolonged exposure.

Groundbreaking research by Ghent University, co-funded by the European Imptox project, has provided new insights into the detrimental effects of repeated low-dose exposure to nanoplastics on cellular health. This pioneering study, led by Imptox researcher Prof. Dr. Andreja Rajkovic, and Prof. Dr. Jana Asselman, replicates very realistic scenarios of low-level, continuous exposure to nanoplastics, as encountered in daily life. Published in Environmental Science & Technology on May 30, 2024, the study demonstrates for the first time that repeated low-level exposure to nanoplastics made from polystyrene - a material widely used in the plastics industry - causes significant damage to mitochondria, the cell’s energy centers, and suppresses cell differentiation under prolonged exposure.

The invisible threat of nanoplastics

Nanoplastics, minute particles smaller than 1,000 nanometres, can be intentionally produced (e.g. for application in the medical or agricultural sector) or result from the degradation of larger plastic debris. Studies have highlighted that even everyday plastic items can release trillions of nanoplastics during regular activities, such as food preparation. These particles, invisible to the naked eye, permeate every aspect of our environment and are present in the air we breathe, the water we drink, and the food we consume. Despite their widespread distribution, our understanding of the long-term health impacts of nanoplastics is still limited, and researchers are only now beginning to develop the sophisticated tools needed to study these minuscule pieces and their potential health risks.

Bridging the gap with an innovative experimental approach

To address this critical research gap, Ghent University researchers have developed an experimental setup that investigates the impacts of both short-term and prolonged exposure to nanoplastics. They use human intestinal cells, which mimic the lining of the human gut, making them ideal for studying the effects of ingested nanoplastics.

The cells were exposed to polystyrene nanoplastics in two different ways:

• Repeated exposure: Cells were subjected to low doses of nanoplastics every two days for a period of 12 days, serving as a realistic proxy for semi and long-term exposure.
• Single exposure: Cells were exposed to nanoplastics once and then observed over the same 12-day period to study the immediate and lingering effects of a one-time exposure.

This dual methodology allowed the scientists to compare the effects of continuous, low-level exposure with those of a single exposure, offering a view of how sustained exposure to nanoplastics might impact human health.

CC-BY Imptox, adapted from original infographic in https://doi.org/10.1021/acs.est.3c10868

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Key findings

The findings revealed significant cellular damage with repeated exposure to nanoplastics, even at low doses. The nanoplastics compromised the mitochondria, leading to decreased mitochondrial function, reduced mitochondrial mass, and impaired cell development. Furthermore, the cells increasingly relied on glycolysis, an inefficient energy production pathway.

After a single exposure to nanoplastics, the cells experienced temporary disruptions in mitochondrial functions and energy production. Alongside this, there was an increase in reactive oxygen species (ROS), which are unstable molecules that can cause significant cellular damage. Despite these initial disturbances, the cells demonstrated a resilient capacity for recovery over time. By the end of the 12-day observation period, no lasting damage was observed confirming that the cells could recover from a one-time exposure.

Implications and future directions

The findings from this study reveal critical insights into the potential health risks of prolonged exposure to nanoplastics. “Our study highlights the crucial need to understand the long-term health risks posed by nanoplastics. Prolonged, low-dose repetitive exposure has shown significant impacts on cellular function, underscoring the importance of continued research in this area,” says Rajkovic. Given that our daily environment exposes us continuously to low levels of nanoplastics, the implications of these findings should not be underestimated, emphasizing the need for comprehensive strategies to mitigate these risks.

Quoted study
Peng, M., Grootaert, C., Vercauteren, M., Boon, N., Janssen, C., Rajkovic, A.*, & Asselman, J. (2024). Probing Long-Term Impacts: Low-Dose Polystyrene Nanoplastics Exacerbate Mitochondrial Health and Evoke Secondary Glycolysis via Repeated and Single Dosing. Environmental Science & Technology. Published May 30, 2024. https://doi.org/10.1021/acs.est.3c10868

News cover image by Freepik. Artist: Julos.