Application of an in vitro reconstructed human skin coculture with THP-1 on cosmetics in skin sensitization.

BACKGROUND

Sensitivity testing for cosmetic formulations mainly involves human patch tests. Cell models, including KeratinoSensTM, ARE-Nrf2 luciferase LuSens and h-CLAT, can predict chemical sensitization according to the OECD 442E standard.

OBJECTIVE

The aim of this study was to identify a potential approach for the assessment of the sensitization potential of cosmetics using skin models cocultured with THP-1 cells.

METHODS

We identified the surface markers CD54 and CD86 in THP-1 cells using flow cytometry and enzyme-linked immunosorbent assays (ELISAs); detected the relative secretion of IL-18, MTT and 7AAD; and evaluated tissue and cell viability. Adverse reactions were analysed using the human patch test.

RESULTS

The relative level of IL-18 secretion after exposure to cinnamyl aldehyde, 2,4-dinitrochlorobenzene, propyl gallate and coumarin was less than 0.79. The relative fluorescence intensity of CD54 was greater than 150, and that for CD86 was greater than 200. Using RFI CD54 ≥ 150, RFI CD86 ≥ 200 or RS IL-18 ≤ 0.79 as the potential sensitization standard, an 18-item cosmetic formulation caused sensitization. Moreover, a 23-item cosmetic formulation caused sensitization in the human patch test. The sensitivity to the products in the in vitro test reached 56.52 %, compared with 75 % for the cleaning products.

CONCLUSION

RFI CD54/CD86 and IL-18 may serve as a new approach to evaluate potential sensitization to cosmetics. In vitro SkinEthic and THP-1 cell coculture combined with the human patch test may better predict potential sensitization to cosmetics.