Probing Long-Term Impacts: Low-Dose Polystyrene Nanoplastics Exacerbate Mitochondrial Health and Evoke Secondary Glycolysis... 2024 Peng et al

Andy

Retired committee member
Full title: Probing Long-Term Impacts: Low-Dose Polystyrene Nanoplastics Exacerbate Mitochondrial Health and Evoke Secondary Glycolysis via Repeated and Single Dosing

Abstract

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Nanoplastics (NPs) are omnipresent in the environment and contribute to human exposure. However, little is known regarding the long-term effects of NPs on human health. In this study, human intestinal Caco-2 cells were exposed to polystyrene nanoplastics (nanoPS) in an environmentally relevant concentration range (102–109 particles/mL) under two realistic exposure scenarios.

In the first scenario, cells were repeatedly exposed to nanoPS every 2 days for 12 days to study the long-term effects. In the second scenario, only nanoPS was added once and Caco-2 cells were cultured for 12 days to study the duration of the initial effects of NPs.

Under repeated dosing, initial subtle effects on mitochondria induced by low concentrations would accrue over consistent exposure to nanoPS and finally lead to significant impairment of mitochondrial respiration, mitochondrial mass, and cell differentiation process at the end of prolonged exposure, accompanied by significantly increased glycolysis over the whole exposure period.

Single dosing of nanoPS elicited transient effects on mitochondrial and glycolytic functions, as well as increased reactive oxygen species (ROS) production in the early phase of exposure, but the self-recovery capacity of cells mitigated these effects at intermediate culture times. Notably, secondary effects on glycolysis and ROS production were observed during the late culture period, while the cell differentiation process and mitochondrial mass were not affected at the end.

These long-term effects are of crucial importance for comprehensively evaluating the health hazards arising from lifetime exposure to NPs, complementing the extensively observed acute effects associated with prevalent short-term exposure to high concentrations. Our study underlines the need to study the toxicity of NPs in realistic long-term exposure scenarios such as repeated dosing.

Paywall, https://pubs.acs.org/doi/10.1021/acs.est.3c10868
 
"Exacerbate" means "make worse" cf "exaggerate" which could be improved or worsened.

"Impair" or "compromise" would have been a better choice, as used in the text.

Discussion said:
The change of bioenergetic health index (BHI), an indicator of mitochondrial health, quantitatively depicted the dynamic transition, where the BHI values of nanoPS-treated Caco-2 cells were far below those of untreated cells, indicative of compromised mitochondrial health.

Overall, the initial slight impacts on mitochondrial respiration (ETC and OXPHOS) by low concentrations would accumulate upon repeated nanoPS exposure and finally lead to significantly impaired mitochondrial functions that are much more serious than acute toxicity at high concentrations. These findings complement the previously documented short-term effects and exhibit possible heightened mitochondrial stress and impairment resulting from long-term exposure, which are implicated in the potential pathogenesis of various human metabolic disorders such as diabetes and obesity, as well as conditions including cancer, cardiovascular disease, and neurodegeneration.
 
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