Treatment of photoaged skin with topical tretinoin increases epidermal-dermal anchoring fibrils: a preliminary report

Photoaging of the skin refers to cumulative damage from sun exposure. There is limited evidence so far that 0.1 percent tretinoin applied directly to the skin can improve the characteristics and appearance of photodamaged skin. In this study, six women (age range, 36 to 55 years) applied tretinoin to one forearm and an inactive placebo cream to the other forearm daily for four months. At the beginning and end of the study, skin biopsies were taken and the structure of the skin was examined using an electron microscope. Specifically, the number of anchoring fibrils in the epidermal-dermal junction were counted; these structures contain the protein collagen. It was theorized that during sun damage, exposure to UV light increases the production of collagenase, the enzyme that breaks down collagen in the skin, and that the collagenase degrades the anchoring fibrils. Tretinoin is believed to inhibit this process, preserving the anchoring fibrils. The anchoring fibrils may literally anchor the layers of skin to one another, straightening out the tiny wrinkles caused by sun damage. Treatment with tretinoin doubled the density of anchoring fibrils as compared with the placebo cream; the increased number of these anchoring fibrils may be responsible for the improved appearance of photoaged skin when treated with tretinoin. (Consumer Summary produced by Reliance Medical Information, Inc.)