Deciphering the links: Fragmented polystyrene as a driver of skin inflammation

Area of Science:

• Environmental Health
• Toxicology
• Dermatology

Background:

• Nano- and microplastics (NMPs) are pervasive environmental contaminants.
• Growing evidence suggests NMPs pose significant risks to human health.

Purpose of the Study:

• To investigate the penetration and inflammatory effects of fragmented polystyrene (fPS) on human skin.
• To quantify fPS penetration depth and amount in various skin models.
• To elucidate the molecular mechanisms of fPS-induced skin inflammation.

Main Methods:

• In-vitro studies using human keratinocyte (HaCaT) and dermal fibroblast (HDF) cells.
• Ex-vivo analysis using 3D human skin models and mouse dorsal skin.
• In-vivo assessment using human abdominal skin models.
• RNA sequencing to analyze gene expression changes.
• Validation of findings at mRNA and protein levels.

Main Results:

• Fragmented polystyrene (fPS) particles were internalized by HaCaT and HDF cells, leading to cytotoxicity.
• fPS penetrated the dermal layer of a 3D human skin model within one hour (avg. 4.7 μg for <2 μm particles).
• RNA sequencing revealed significant upregulation of key inflammatory genes (e.g., IL-1α, IL-6, IL-8, ICAM-1).
• Inflammatory response showed a dose-dependent increase in 3D human and mouse skin models.

Conclusions:

• Fragmented polystyrene readily penetrates human skin models.
• fPS exposure induces a robust, dose-dependent inflammatory response in the skin.
• These findings highlight the toxicological impact of NMPs on skin health and necessitate further research for mitigation.