Development of a lip vermilion epithelium reconstruction model using keratinocytes from skin and oral mucosa.

Kobayashi, Eri; Ling, Yiwei; Kobayashi, Ryota; Hoshikawa, Emi; Itai, Eriko; Sakata, Osamu; Okuda, Shujiro; Naru, Eiji; Izumi, Kenji

Lip vermilion is unique and can be distinguished from the adjacent skin and oral mucosa. However, because of the lack of appropriate evaluation tools, skin and/or oral mucosa substitutes such as in vitro vermilion epithelial models have been used for lip product testing. We aimed to develop and characterize a lip vermilion epithelium reconstruction model (LVERM) using skin and oral keratinocytes. LVERM was manufactured by co-culturing primary skin and oral keratinocytes, using a device that allowed the separation of cell seeding, and created an intercalated cell-free zone, referred to as the vermilion part. After removing the device, LVERM construction was completed in 8 days, in a submerged condition. Subsequently, they were placed in an air–liquid interface for 7 days. To determine the epithelial characteristics of LVERM, keratin 2e (KRT2) and small proline-rich protein 3 (SPRR3) expression patterns were examined. The in vivo expression profiles of KRT2 and SPRR3 genes in vermilion were also examined. We found that a continuous multi-layered epithelium was generated in the LVERM that exhibited ortho- and para-keratinization in the skin and oral mucosa parts, respectively. Although an intermediate keratinization pattern was observed in the vermilion part, KRT2 and SPRR3 were co-expressed in the suprabasal layer, consistent with the expression pattern of a single vermilion epithelial model. Clustering analysis revealed that KRT2 and SPRR3 gene expression in vermilion was location-dependent within the sample. Therefore, LVERM can be used as an evaluation tool for lip products and has great importance in innovative approaches for cosmetic testing.

ORAL mucosa; EPITHELIUM; KERATINOCYTES; GENE expression; LIPS; KERATINIZATION; CELL separation

Histochemistry & Cell Biology, 2023, Vol 160, Issue 4, p349

0948-6143

Academic Journal

10.1007/s00418-023-02206-4