1. Effect of increased pigmentation on the antifibrotic response of human skin to UV-A1 phototherapy.
- Author
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Wang F, Garza LA, Cho S, Kafi R, Hammerberg C, Quan T, Hamilton T, Mayes M, Ratanatharathorn V, Voorhees JJ, Fisher GJ, and Kang S
- Subjects
- Adult, Collagen Type I genetics, Collagen Type I metabolism, Collagen Type III genetics, Collagen Type III metabolism, Dose-Response Relationship, Radiation, Female, Humans, Hyperpigmentation pathology, Male, Matrix Metalloproteinases genetics, Matrix Metalloproteinases metabolism, Polymerase Chain Reaction, RNA, Messenger analysis, Radiation Dosage, Scleroderma, Localized pathology, Severity of Illness Index, Treatment Outcome, Ultraviolet Rays, Hyperpigmentation etiology, Scleroderma, Localized radiotherapy, Skin radiation effects, Ultraviolet Therapy adverse effects
- Abstract
Objective: To investigate the efficacy, potential limitations, and biological mechanisms of UV-A1 phototherapy for skin sclerosis due to collagen deposition disorders., Design: Before-and-after trial of UV-A1 irradiation of sclerotic skin; in vivo biochemical analyses after UV-A1 irradiation of normal skin., Setting: Academic referral center., Participants: Patients with morphea/scleroderma or sclerodermoid graft-vs-host disease and volunteers without skin disease. Intervention Sclerotic skin was treated with high-dose (130 J/cm(2); n = 12) or medium-dose (65 J/cm(2); n = 6) UV-A1 phototherapy 3 times per week for 14 weeks; normal skin was treated with UV-A1 irradiation at various doses and frequencies, with biopsies performed afterwards., Main Outcome Measures: In sclerotic skin, induration was clinically assessed using a scoring scale. In normal skin, quantitative polymerase chain reaction was used to assess antifibrotic responses, defined as decreased type I and type III procollagen and increased matrix metalloproteinase levels., Results: In patients with sclerotic skin treated with high-dose UV-A1 irradiation, clinical scores for induration modestly decreased. To investigate what factors prevented further improvement (ie, complete clearance), normal skin with light pigmentation was exposed to UV-A1 irradiation (70-150 J/cm(2)) and was assessed for antifibrotic responses. A single high-dose exposure (110-150 J/cm(2)) elicited substantial antifibrotic responses and induced skin darkening. This skin darkening attenuated responses to subsequent UV-A1 exposures and was dose dependent. Thus, to minimize skin darkening, additional patients with sclerotic skin were treated with medium-dose UV-A1 phototherapy, which was no less effective than high-dose therapy., Conclusion: Clinical responses of sclerotic skin to UV-A1 phototherapy were modest because of UV-A1-induced skin darkening, which is photoprotective and attenuates antifibrotic responses., Trial Registration: clinicaltrials.gov Identifier: NCT00129415.
- Published
- 2008
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