Restoration of collagen formation in photodamaged human skin by tretinoin (retinoic acid)

A correlation may exist between topical application of tretinoin and an increase in collagen I production in sun-damaged skin. The formation of collagen, a protein that is a component of connective tissue, is decreased in sun-damaged human skin. Skin biopsies were performed on 26 healthy, white participants. Analysis of biopsies from sun-protected areas of the buttocks and sun-damaged areas of the participants' forearms indicated that collagen I formation was significantly lessened in the damaged skin. An additional 29 white patients were randomly assigned to apply either a topical preparation of 0.1% tretinoin cream or a similar-looking placebo cream with no active ingredients. Some of the patients were treated for 10 months and some for 12 months. Biopsies were performed before treatment began and again at the end of treatment. Analysis of the biopsies found a 119% increase in collagen I staining of fibroblasts and an 80% increase in extracellular collagen I formation in patients treated with tretinoin. There was an 18% decrease in collagen staining of fibroblasts in patients who received the placebo.