title: Indole-3-acetic acid: a potential new photosensitizer for photodynamic therapy of acne vulgaris.
abstract: OBJECTIVE
  ALA (5-aminolevulinic acid) photodynamic therapy (PDT) is a new treatment option for acne. However, it needs a relatively long incubation period and adverse effects are common. Indole-3-acetic acid (IAA) is not toxic by itself but produces free radicals with ultraviolet B. In this study we examined the potential of IAA as a photosensitizer for acne treatment.
  
  
  METHODS
  Free radical formation was measured after visible light irradiation of IAA. Antimicrobial effect was evaluated by assessing growth suppression of Propionibacterium acnes and Staphylococcus aureus after IAA PDT. To evaluate the histological changes, skin biopsies were performed on nude mice skin after IAA PDT. To evaluate the clinical efficacy of IAA PDT, 14 acne patients were treated with the following IAA PDT regimen: three times each with a 15 minutes incubation period and a 2-week interval. The number of inflammatory lesions and the amount of sebum secretion were then assessed.
  
  
  RESULTS
  IAA produced free radicals with green light irradiation. Importantly, IAA lost its photosensitizing ability after exposure to certain amount of light. This implies IAA PDT would not require post-procedure photo-protection. The growth of P. acnes and S. aureus were significantly suppressed with IAA PDT. In addition, IAA PDT treated skin showed destruction of follicular ostia epithelium. Interestingly, there was no significant difference between a 4 hours and a 30 minutes incubation, which means that longer absorption time is not necessary for IAA PDT. In the clinical study, inflammatory lesions and sebum secretion were significantly reduced. The procedure was painless and no adverse effect was observed. Photo-protection was not performed and there were no further phototoxic responses.
  
  
  CONCLUSIONS
  IAA PDT has therapeutic effects on acne via its antimicrobial activities, its sebum-reducing effect and through relieving follicular occlusion. It is a very simple and safe treatment option for acne.
authors.affiliation: Department of Dermatology, Seoul National University College of Medicine, Seoul National University Bundang Hospital, Seoul, Korea.
authors.forename: Jung-Im
authors.initials: JI
authors.lastname: Na
authors.forename: So-Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Jeong-Hye
authors.initials: JH
authors.lastname: Kim
authors.forename: Sang-Woong
authors.initials: SW
authors.lastname: Youn
authors.forename: Chang-Hun
authors.initials: CH
authors.lastname: Huh
authors.forename: Kyoung-Chan
authors.initials: KC
authors.lastname: Park
mesh_terms: D000152:Acne Vulgaris / Q000188:drug therapy* / Q000382:microbiology / Q000473:pathology; D000818:Animals; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D004847:Epithelial Cells / Q000187:drug effects / Q000473:pathology; D005609:Free Radicals / Q000378:metabolism; D018859:Hair Follicle / Q000187:drug effects / Q000473:pathology; D006801:Humans; D007210:Indoleacetic Acids / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D010865:Pilot Projects; D011425:Propionibacterium acnes / Q000187:drug effects; D012627:Sebaceous Glands / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D012629:Sebum / Q000378:metabolism; D013211:Staphylococcus aureus / Q000187:drug effects; D016896:Treatment Outcome
chemical_list: D005609:Free Radicals; D007210:Indoleacetic Acids; D017319:Photosensitizing Agents; C030737:indoleacetic acid