title: Efficacy and possible mechanisms of topical tranexamic acid in melasma.
abstract: BACKGROUND
  Tranexamic acid (TA) has been suggested as an effective treatment for melasma.
  
  
  OBJECTIVE
  To investigate the effects and mechanism of action of topical TA in the treatment of melasma.
  
  
  METHODS
  In this study, 23 participants with melasma applied a 2% TA formulation to the whole face for 12 weeks. Clinical effects were evaluated using the modified Melasma Area and Severity Index (mMASI) and a chromameter. Skin biopsies were obtained from 10 participants to evaluate pigmentation, vascularity and the expression levels of possible paracrine factors contributing to the effect of TA.
  
  
  RESULTS
  Most of the participants had mild melasma, with mMASI of < 5. The mMASI scores significantly improved in 22 of 23 participants after application. The L* values were increased and the a* values were decreased in both lesional and perilesional normal skin. Fontana-Masson staining showed a significant decrease in melanin content in the epidermis. The number of CD31-positive vessels and the expression of the vascular endothelial growth factor both tended to decrease. Endothelin (ET)-1 was found to be downregulated with TA.
  
  
  CONCLUSIONS
  Topical TA is effective for melasma. This immunohistochemical study found that suppression of ET-1 could be one of the mechanisms of action of TA on melasma.
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: S J
authors.initials: SJ
authors.lastname: Kim
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: J-Y
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: T
authors.initials: T
authors.lastname: Shibata
authors.affiliation: Shiseido Research Center, Yokohama, Japan.
authors.forename: R
authors.initials: R
authors.lastname: Fujiwara
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: H Y
authors.initials: HY
authors.lastname: Kang
mesh_terms: D000328:Adult; D000933:Antifibrinolytic Agents / Q000627:therapeutic use*; D015415:Biomarkers / Q000378:metabolism; D019332:Endothelin-1 / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008548:Melanosis / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D008875:Middle Aged; D012720:Severity of Illness Index; D014148:Tranexamic Acid / Q000627:therapeutic use*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D000933:Antifibrinolytic Agents; D015415:Biomarkers; D019332:Endothelin-1; D042461:Vascular Endothelial Growth Factor A; D014148:Tranexamic Acid