Imptox researchers from Ghent University recently published their findings in Environmental Pollution illuminating the long-term impact of microplastics on human cells.

In the intricate realm of microplastics, the pervasive presence of these minuscule particles in our food and personal care products has sparked significant concern about their implications for human health which are not yet fully understood.

In a comprehensive study, Imptox researchers from Ghent University, spearheaded by Prof. Andreja Rajkovic, in cooperation with colleagues from the Laboratory for Environmental Toxicology, delved into the cellular and bioenergetic effects of microplastics, specifically polystyrene (PS), under various exposure scenarios. Published in Environmental Pollution, and available online since September 15, 2023, the study focused on four human cell lines derived from crucial organs: lung (A549 and BEAS-2B), colon (Caco-2), and liver (HepG2). These cell lines, representing major exposure routes in the body (inhalation, ingestion, and detoxification), were exposed to 2-μm PS microspheres at concentrations ranging from 10² to 10⁵ particles/mL.

KEY ASPECTS EXPLORED

1. Cellular Uptake Dynamics: The undifferentiated Caco-2 cells, in particular, displayed a remarkable uptake rate of PS during short exposures (48 hours). Intriguingly, differentiation states of A549 and Caco-2 cells did not significantly influence the biological effects, except for reactive oxygen species (ROS) production, despite differentiated cells showing a weaker ability to internalize PS.
2. Long-term Impact: The most striking revelation was the enduring impact of polystyrene on cellular and mitochondrial functions, persisting even after the initial exposure period. Caco-2 cells, post-exposed for 12 days following a single PS dosing, exhibited elevated oxidative stress and mitochondrial dysfunction. PS particles were observed to endure in cell membranes and nuclei, indicating chronic stress induced by these microplastics.
3. Real-life Scenario Exploration: This study used lower particle concentrations (10²-10⁵ particles/mL) than those used in most studies (10⁴ and 10¹² particles/mL), as the lower concentrations are closer to the currently documented real-life exposure scenarios for humans (no more than 10⁵ particles/mL ). Furthermore, the researchers used PS particles with a size of 2 μm, ensuring relevance to real-life exposure scenarios. Larger particles were deemed non-internalizable, while nano-sized particles' exposure concentrations were challenging to validate due to limited human exposure data.

This study marks a further step toward understanding the nuanced impact of microplastics on human cells. Prof. Rajkovic’s research team has created a unique pioneering workflow that combines single plate analysis in Agilent Seahorse XFe96 and Sartorius Incucyte SX5 instruments for in-depth studies of the bioenergetic status of human cells in function of micro(nano)plastics exposure and their cargo. By considering differentiation status, cell type, and extended exposure periods, it provides a comprehensive perspective. The scientists utilized polystyrene, a common component in various plastic products, to bridge their findings with existing research conducted at higher exposure concentrations. The meticulous assessment of cellular responses, metabolism indicators, and dynamic particle behaviour underpins their commitment to a thorough risk evaluation of microplastics' impact on human health.

Stay tuned as we continue our journey, probing the unseen realms of micro and nanoplastics, safeguarding human health one discovery at a time.

Reference:

Miao Peng, Maaike Vercauteren, Charlotte Grootaert, Andreja Rajkovic, Nico Boon, Colin Janssen, Jana Asselman, “Cellular and bioenergetic effects of polystyrene microplastic in function of cell type, differentiation status and post-exposure time”, Environmental Pollution, Volume 337, 2023.

https://doi.org/10.1016/j.envpol.2023.122550

Keywords:

microplastics, nanoplastics, human health, polystyrene, microbiology, plastic pollution, science