Tretinoin

Tretinoin Treatment before Carbon Dioxide Laser Resurfacing: A Clinical and Biochemical Analysis

Orringer JS, MD, Kang S, MD, Johnson TM, MD, et al. J Amer Acad Dermatol. 2004;51:940-6.

Summary

The authors present a prospective, randomized, double-blind clinical trial to ascertain the validity of using tretinoin prior to carbon dioxide resurfacing in order to enhance results. Clinical and biochemical outcomes were sought. It is known that C[O.sub.2] laser-treated photo-damaged skin has increased mRNA levels of matrix metalloproteinases (MMPs)-1, 3, and 9, as well as increased levels of type I and III procollagen. Since tretinoin has been shown to inhibit induction of MMPs and stimulate collagen production in photodamaged skin, levels of types I and III collagen and MMPs-1, 3, and 9 were calculated to determine if these specific actions had a positive influence on results of resurfacing. Eleven patients with moderate to severe photodamage of the forearms were enrolled and randomized to use tretinoin 0.05% cream or vehicle cream daily for 3 weeks before undergoing resurfacing. Focal areas of the forearms were then treated with the Coherent Ultrapulse C[O.sub.2] laser. Next, 3-mm punch biopsies were taken from laser-treated areas at various points between day 1 and 6 months post-treatment. Total RNA was extracted from each biopsy and then levels of mRNA for types I and III collagen and MMPs-1, 3, and 9 were determined. Regarding clinical outcomes, separate areas of the forearms were treated with the C[O.sub.2] laser. Areas were then evaluated on days 7, 14, 21, and 28 after resurfacing to determine the clinical appearance of the wounds and the amount of re-epithelialization. These same areas were also evaluated by a colorimeter to determine levels of postoperative erythema on day 28, 3 months, and 6 months. There were no statistically significant differences in levels of both MMPs and collagens found between tretinoin-treated and untreated skin. There were also no clinically or statistically significant differences in rates of re-epithelialization or in intensity of erythema between treated and untreated skin.

Comment

This study is important in that it tests a commonly practiced treatment regimen that has not been fully evaluated for its efficacy. Although many dermatologists use this treatment regimen, this study failed to reveal any advantage of using tretinoin before C[O.sub.2] laser resurfacing. The study had some limits, given its small sample size and the inability of this study to be performed on the face. Also, only one concentration of tretinoin was used. Perhaps higher concentrations are needed and for longer periods of time prior to treatment. If in fact tretinoin has enhanced results clinically, the study provides data that this action is not through the inhibition of induction of MMPs or through stimulating collagen production. The authors raise an interesting point of using tretinoin in the post-treatment period.

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