title: Photorejuvenation induced by 5-aminolevulinic acid photodynamic therapy in patients with actinic keratosis: a histologic analysis.
abstract: BACKGROUND
  Repeated exposure to ultraviolet radiation from the sun results in premature photoaging. Photodynamic therapy (PDT) has been shown to be effective for treatment of photoaging, although the data from most studies have been based on clinical observation.
  
  
  OBJECTIVE
  We investigated whether 5-aminolevulinic acid (ALA)-PDT induced histologic changes suggesting photorejuvenation.
  
  
  METHODS
  Fourteen patients with one to three actinic keratoses on the face were treated twice with ALA-PDT by using a 1200 W metal halogen lamp at 1-month intervals. Skin biopsy before and 1 month after the PDT was performed. Twenty-five pairs of specimens were obtained. We examined the specimens with routine and immunohistochemical staining and evaluated the parameters associated with photoaging by using image analysis.
  
  
  RESULTS
  After ALA-PDT, the mean epidermal thickness and dermal inflammatory infiltrate were reduced. The total collagen volume in the dermis significantly increased with expression of type I and III procollagen. The level of transforming growth factor beta and transforming growth factor beta type II receptors in the epidermis also increased. The elastotic material with co-localizing fibrillin-1 and tropoelastin expression in the dermis decreased after treatment. The expression of matrix metalloproteinases-1, -3, and -12 also decreased.
  
  
  CONCLUSIONS
  The study was limited by the small sample size.
  
  
  CONCLUSIONS
  ALA-PDT resulted in histological changes indicating restoration of photoaged skin. These data suggest that ALA-PDT could be effective for photorejuvenation.
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Min Young
authors.initials: MY
authors.lastname: Park
authors.affiliation: Laboratory of Cell Biology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Seonghyang
authors.initials: S
authors.lastname: Sohn
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea.
authors.forename: Eun-So
authors.initials: ES
authors.lastname: Lee
authors.affiliation: Department of Dermatology, Ajou University School of Medicine, Suwon, Korea. Electronic address: maychan@ajou.ac.kr.
authors.forename: You Chan
authors.initials: YC
authors.lastname: Kim
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000622:Aminolevulinic Acid / Q000627:therapeutic use*; D005260:Female; D000071838:Fibrillin-1; D000071837:Fibrillins; D006801:Humans; D007150:Immunohistochemistry; D055623:Keratosis, Actinic / Q000188:drug therapy* / Q000473:pathology; D008297:Male; D020782:Matrix Metalloproteinases / Q000378:metabolism; D008840:Microfilament Proteins / Q000378:metabolism; D008875:Middle Aged; D010778:Photochemotherapy; D017319:Photosensitizing Agents / Q000627:therapeutic use*; D011347:Procollagen / Q000378:metabolism; D018125:Receptors, Transforming Growth Factor beta / Q000378:metabolism; D012060:Rejuvenation; D016212:Transforming Growth Factor beta / Q000378:metabolism; D014333:Tropoelastin / Q000378:metabolism; D054392:Adipokines
chemical_list: D000622:Aminolevulinic Acid; D000071838:Fibrillin-1; D000071837:Fibrillins; D020782:Matrix Metalloproteinases; D008840:Microfilament Proteins; D017319:Photosensitizing Agents; D011347:Procollagen; D018125:Receptors, Transforming Growth Factor beta; D016212:Transforming Growth Factor beta; D014333:Tropoelastin; C000605722:FBN1 protein, human; D054392:Adipokines