Application of glucosylceramide-based liposomes increased the ceramide content in a three-dimensional cultured skin epidermis.

Ceramide is an intercellular lipid of the stratum corneum and is one of the most important components of the epidermal permeability barrier. Glucosylceramide (GlcCer), a ceramide precursor, was applied to three-dimensional skin culture to regulate ceramide. GlcCer/dimyristoylphosphatidylcholine (DMPC) = 4/4 (molar ratio and GlcCer/DMPC/dimyristoylphosphatidylglycerol (DMPG) = 4/4/1(molar ratio) liposomes were prepared by the thin-layer method. The particle diameters of GlcCer/DMPC and GlcCer/DMPC/DMPG liposomes were 124.0 ± 0.6 and 119.3 ± 18.9 nm, and the zeta potentials were 1.3 ± 0.3 and -19.9 ± 0.3 mV, respectively. Stability of these GlcCer liposomes was measured by transmission light scattering. Transmission light scattering of neutrally charged GlcCer (GlcCer/DMPC) liposomes increased in a time dependent manner. In contrast, negatively charged GlcCer (GlcCer/DMPC/DMPG) liposomes were not changed. ß-Glucocerebrosidase activity was measured in a cultured human skin model. Results confirmed that the cultured human skin model has ß-glucocerebrosidase activity. GlcCer/DMPC/DMPG liposomes were applied to the three-dimensional cultured human skin model, and ceramide NS, NP, AS, and AP were extracted from it. The various extracted ceramides were separated by high-performance thin-layer chromatography and quantified by a densitometer. The amount of ceramide AS only in the cultured skin model was significantly higher with the application of GlcCer-based liposomes than that of the nonapplication group, and was also dose dependent. Thus, GlcCer-based liposomes are useful for enriching the ceramide AS levels in a three-dimensional cultured skin model.