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In vitro effects of polystyrene microplastics exposure on adipose tissue dysfunction

Toxicology in Vitro 2026
Maria Sofia Molonia, Santi Trischitta, Federica Lina Salamone, Antonella Saija, Antonio Speciale, F Cimino

Summary

Researchers exposed adipose tissue cells to polystyrene microplastics and found that the effects depended on the developmental stage of the cells. While fully mature fat cells showed minimal changes, microplastics exposure during the differentiation process significantly promoted fat cell enlargement, triggered oxidative stress, endoplasmic reticulum stress, and inflammatory responses. The findings suggest that microplastics may be more disruptive to fat tissue during its formation than after it has matured.

Polymers
Body Systems
Models
Study Type In vitro

Microplastics (MPs) are ubiquitous plastic particles with significant human health concerns due to their widespread distribution in the environment. The present study aims to evaluate the impact of exposure to polystyrene (PS) MPs (5 μm) on adipose tissue functionality using a well-established in vitro model of murine 3T3-L1 adipocytes, mimicking two distinct environmental exposure scenarios: fully differentiated mature adipocytes and preadipocytes undergoing the differentiation process. In fully differentiated adipocytes, PS MPs exposure did not produce significant alterations in key markers of adipogenesis (PPARγ and FASN), endoplasmic reticulum (ER) stress (p-eIF2α and GRP78), or inflammation (IL-6 and MCP-1). Interestingly, PS MPs exposure during adipocyte differentiation process significantly promoted adipocyte hypertrophy, as evidenced by the upregulation of adipogenic markers. Additionally, MPs induced reactive oxygen species and main key markers of the ER stress response and apoptosis. Finally, our results demonstrated that PS MPs exposure triggered an inflammatory response. In conclusion these findings underscore the multifaceted impact of PS MPs on adipose tissue during differentiation, demonstrating their ability to perturb oxidative balance and ER homeostasis, and to induce inflammatory signaling. Finally, our results emphasize the importance of the stage-specific responses in assessing the impact of environmental contaminants on adipose tissue function. • PS MPs promote adipogenesis, endoplasmic reticulum stress and inflammation. • In fully differentiated adipocytes, PS MPs no affects metabolic dysregulation. • PS MPs disrupt adipose tissue homeostasis, contributing to metabolic dysfunction.

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