Retinyl retinoate induces hyaluronan production and less irritation than other retinoids.

Hyaluronan, a non-sulfated glycosaminoglycan, retains water, maintains the extracellular spaces and facilitates the transport of ion solutes and nutrients. Hyaluronan is closely involved in keratinocyte proliferation, migration and differentiation. The synthesis of hyaluronan in vitro can be stimulated by several growth factors, including retinoids, dibutyryl cyclic adenosine monophosphate and peroxisome proliferator-activated receptor-alpha agonist. In this study, we examined retinyl retinoate (a novel retinol derivative) on hyaluronan expression in primary human keratinocytes and in hairless mouse epidermal skin. Histochemistry using hyaluronan-binding protein revealed that topical retinyl retinoate increased the intensity of hyaluronan staining in murine skin. Moreover, topical retinyl retinoate increased CD44 (hyaluronan receptor) expression. Using reverse transcription polymerase chain reaction, we assessed the expression level of the hyaluronan synthase 2 (HAS2) gene in primary human keratinocytes and in hairless mouse epidermal skin. We found that retinyl retinoate upregulated mouse HAS2 and human HAS2 mRNA. Application of retinyl retinoate induced increasing transepidermal water loss less than retinol, retinoic acid and retinaldehyde. Taken together, we suggest that retinyl retinoate is more effective on hyaluronan production and less of an irritant than other retinoids.