Anti-ageing effects of a new synthetic sphingolipid (K6EAA-L12) on aged murine skin.

Recently, we reported on the anti-ageing effects of K6PC-5. This compound induced keratinocyte differentiation and fibroblast proliferation by increasing sphingosine-1 phosphate synthesis. We performed this study to confirm the anti-ageing effects of new synthetic products (the K6EAA series) derived from K6PC-5 through an amino group induction. Cellular responses such as differentiation, proliferation and calcium mobilization were investigated using cultured human keratinocytes and fibroblasts. Also, we measured the expressions of collagen mRNA and protein using real time RT-PCR and ELISA, respectively. The K6EAA-L12 product, selected by in vitro screening, was evaluated for anti-ageing effects on intrinsically and extrinsically (photo) aged models of hairless mice. In the intrinsically aged murine skin, K6EAA-L12 showed anti-ageing effects by activating collagen synthesis, eventually causing dermal thickening. Also, in the photo-aged skin, the dermal collagen density and dermal thickness were increased. In photo-aged murine skin, K6EAA-L12 increased stratum corneum integrity by increasing corneodesmosome density and improved the barrier recovery rate. However, there were no changes in the expressions of epidermal differentiation maker proteins. In conclusion, topical K6EAA-L12, a new synthetic K6PC-5 derivative, improves intrinsically and extrinsically (photo) aged skin by increasing the collagen density and improving the skin barrier function.