DNA Methyltransferases in Malar Melasma and Their Modification by Sunscreen in Combination with 4% Niacinamide, 0.05% Retinoic Acid, or Placebo

The study investigated the role of DNA methyltransferases (DNMTs) in malar melasma and the effects of treatments combining sunscreen with 4% niacinamide, 0.05% retinoic acid, or placebo on these enzymes. Conducted on 30 female patients, the research found that DNMT1 expression was significantly higher in melasma-affected skin, indicating DNA hypermethylation. After 8 weeks of treatment, DNMT1 levels decreased across all groups, correlating with clinical improvement. DNMT3b was not overexpressed in affected skin but was reduced in all treatment groups. The study concluded that environmental factors like solar radiation might induce hyperpigmentation through epigenetic changes, but treatments that reduce DNA methylation can counteract these effects.