Phototherapeutic modalities pose no significantly increased risk of oxidative damage to DNA in dark skinned individuals.

Autor: Youssef R; Department of Dermatology, Faculty of Medicine, Cairo University, Cairo, Egypt., Ossama S; Department of Dermatology, Faculty of Medicine, Cairo University, Cairo, Egypt., Mashaly HM; Department of Dermatology, Faculty of Medicine, Cairo University, Cairo, Egypt., Fathy M; Department of Dermatology, Faculty of Medicine, Cairo University, Cairo, Egypt., Safwat M; Department of Dermatology, Faculty of Medicine, Cairo University, Cairo, Egypt., Shaker O; Department of Medical Biochemistry, Faculty of Medicine, Cairo University, Cairo, Egypt., El-Mofty M; Department of Dermatology, Faculty of Medicine, Cairo University, Cairo, Egypt.
Jazyk: angličtina
Zdroj: Indian journal of dermatology, venereology and leprology [Indian J Dermatol Venereol Leprol] 2016 Nov-Dec; Vol. 82 (6), pp. 666-672.
DOI: 10.4103/0378-6323.186485
Abstrakt: Background: 8-oxoguanine, a major product of DNA oxidation, is considered a key parameter in measuring the carcinogenic effects of ultraviolet radiation.
Objective: To assess and compare the carcinogenic potential of different photo (chemo) therapeutic modalities in photoresponsive skin diseases by measuring the levels of 8-oxoguanine in dark-skinned individuals before and after photo (chemo) therapy.
Methods: A prospective, randomized controlled pilot study was conducted in 63 patients of skin types III-V with photo-responsive dermatoses including vitiligo, psoriasis and mycosis fungoides. Patients were divided into three groups; Group 1 (received narrowband ultraviolet-B), Group 2 (received psoralen plus ultraviolet-A) and Group 3 (received broadband ultraviolet-A). Biopsies were taken before and after phototherapy to measure 8-oxoguanine levels using enzyme-linked immunosorbent assay. Biopsies were also taken from the sun-protected skin in 21 controls subjects who had no dermatological disease.
Results: Regardless of the disease, a significantly higher level of 8-oxoguanine was found after treatment when compared to the pre-treatment baseline levels; however, these levels were comparable to those in control subjects. A weakly significant positive correlation was found between cumulative dose and 8-oxoguanine levels following psoralen plus ultraviolet-A therapy. In controls, comparing the 8-oxoguanine levels between skin types III and IV showed significantly lower 8-oxoguanine in skin type IV.
Conclusion: Therapeutic doses of ultraviolet radiation are relatively safe in dark skinned patients; however, minimizing the cumulative dose of phototherapeutic modalities (particularly psoralen plus ultraviolet-A) is recommended.
Databáze: MEDLINE
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