Aging of the Epidermis: Another Role for Hyaluronic Acid ?
-When senescence occurs, the epidermis becomes thinner (atrophic).
-This study shows that stem cells are still present in the epidermis (LRIG+ cells interfollicular epidermis in mice), but that there is reduced wnt signaling (reduced lef1 expression).
-The wnt signaling pathway controls adult tissue regeneration in skin, intestine and bone barrow.
-CD44 down regulation is part of senescent epidermis . (Hyaluronic Acid is ineffective in CD44 knock out mice)