DNA Methylation in Malar Melasma and Its Change by Sunscreen, Retinoic Acid and Niacinamide.

Recognize the DNA methylation status of the malar melasma and perilesional skin, and its change after treatment with 50 SPF sunscreen (S), 4% niacinamide (N), or 0.025% retinoic acid (RA). METHODS: Fifty-six lesion of 28 female patients without treatment were clinically evaluated, as also the expression of DNA methyl transferases 1 and 3 by real time-PCR (polymerase chain reaction amplification), immunohistochemistry and immunofluorescence. It was initially quantified and after 8 weeks of treatment with S, RA and N. RESULTS: Relative expression of DNA methyl transferases were significantly elevated compared with unaffected skin in all subjects indicating hypermethylation of DNA. Hypermethylation decreased by S (7 vs 3 times relative expression, p<0.05), RA (7 vs 2 times relative expression p<0.05), and N (7 vs 1 relative expression p<0.01) correlated with clinical improvement, this was also supported by immunohistochemistry and immunofluorescence. CONCLUSIONS: The investigators found hypermethylation of DNA in melasma lesions. Environmental factors such as sun radiation may induce DNA hypermethylation triggering hyperpigmentation trough the activation of pathways regulated by epigenetic modifications. Thus, decreasing methylation by sunscreen protection and the genetic transcription modification through N and RA, may allow their clinical improvement regardless its depigmenting effect.