title: Hypo-collagenesis in photoaged skin predicts response to anti-aging cosmeceuticals.
abstract: BACKGROUND
  Chronic sun exposure causes photoaging, the appearance of prematurely aged skin. This phenomenon is characterized by progressive alteration of the dermal extracellular matrix, including elastin and collagen fibers. While many cosmeceuticals claim to improve the appearance of photoaged skin, data are lacking regarding their ability to induce molecular responses associated with wrinkle effacement, particularly increased collagen production.
  
  
  OBJECTIVE
  To conduct a meta-analysis to determine whether there was a factor(s) that could predict response to various cosmeceuticals.
  
  
  METHODS
  Hundred subjects enrolled in five separate studies of cosmeceuticals containing: L-ascorbic acid, pentapeptide, α-lipoic acid, yeast extract, or 1% idebenone. Five groups consisting of 16-20 volunteers applied one cosmeceutical to their photodamaged forearms for several weeks. Punch biopsies were obtained pretreatment and post-treatment and analyzed for type I procollagen by ELISA.
  
  
  RESULTS
  Analysis of basal collagenesis reinforced the notion that hypo-collagenesis is associated with photoaging severity, independent of age or gender. Treatment outcome varied greatly among subjects, ranging from no improvement to a 7-fold increase in collagenesis. Retrospective statistical meta-analysis was conducted to determine whether age, gender, type of cosmeceutical, or evidence of hypo-collagenesis in untreated skin could predict responsiveness to cosmeceuticals. Our analysis revealed that subjects with hypo-collagenesis responded 6.4 times more often than subjects with normo-collagenesis.
  
  
  CONCLUSIONS
  Hypo-collagenesis was the only factor that influenced treatment outcome. This study therefore identifies hypo-collagenesis as the unique parameter predicting anti-aging cosmeceutical treatment outcome. These findings provide a basis for future cosmetic testing and the potential development of custom formula skin care.
authors.affiliation: Department of Dermatology, University of Michigan, Ann Arbor, Michigan, USA. dsachs@med.umich.edu
authors.forename: Dana L
authors.initials: DL
authors.lastname: Sachs
authors.forename: Laure
authors.initials: L
authors.lastname: Rittié
authors.forename: Heather A
authors.initials: HA
authors.lastname: Chubb
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Orringer
authors.forename: Gary
authors.initials: G
authors.lastname: Fisher
authors.forename: John J
authors.initials: JJ
authors.lastname: Voorhees
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000975:Antioxidants / Q000494:pharmacology; D001205:Ascorbic Acid / Q000494:pharmacology; D002457:Cell Extracts / Q000494:pharmacology; D003358:Cosmetics / Q000494:pharmacology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011347:Procollagen / Q000096:biosynthesis*; D014176:Protein Biosynthesis / Q000187:drug effects*; D012867:Skin / Q000187:drug effects* / Q000378:metabolism*; D015595:Skin Aging / Q000187:drug effects* / Q000502:physiology; D008063:Thioctic Acid / Q000494:pharmacology; D014451:Ubiquinone / Q000031:analogs & derivatives / Q000494:pharmacology; D015003:Yeasts
chemical_list: D000975:Antioxidants; D002457:Cell Extracts; D003358:Cosmetics; D011347:Procollagen; D014451:Ubiquinone; D008063:Thioctic Acid; C036619:idebenone; D001205:Ascorbic Acid