title: One week's holiday sun exposure induces expression of photoaging biomarkers.
abstract: BACKGROUND
  Skin aging is accompanied by the upregulation of the expression of various matrix metalloproteinases (MMPs). It was shown that exposure to ultraviolet radiation (UVR) may induce skin expression of MMPs and dysregulation of the transforming growth factor beta (TGF-β)/Smad pathway. The aim of our study was to compare the effects of short holiday UVR exposure and lifetime UVR exposure, on the expression of MMP-8, TGF-β1, and Smad2 in human skin biopsies.
  
  
  METHODS
  Skin biopsies were taken from the outer upper arm of 15 elderly people with significant photoaging (mean age 64.1 years) (Group 1) and from 15 healthy young adult volunteers (mean age 24.1 y) who participated in a six-day sun holiday. Biopsies were taken twice: 24 hours before leaving for holiday (Group 2a) and 24 hours after returning (Group 2b). The expression of TGF-β1, Smad2, and MMP-8 was examined by immunochemistry and measured semiquantitatively by two independent pathologists.
  
  
  RESULTS
  The mean expression of TGF-β1 in dermal fibroblasts and keratinocytes in Group 1 and Group 2b was significantly lower than in Group 2a (0.54% ± 0.44% and 0.48% ± 0.51% vs. 1.48% ± 0.72%, respectively). The percentage of Smad2 (+) cells in Group 1 and Group 2b was lower than in Group 2a (2.13% ± 1.39% and 1.81% ± 1.16% vs. 4.13% ± 1.58%, respectively). The MMP-8 expression in Group 2b was 1.36% ± 0.68% and was significantly higher than in Group 1 (0.34% ± 0.42%) and Group 2a in which the protein was not detected (p < 0.001).
  
  
  CONCLUSIONS
  We conclude that the decrease in the expression of TGF-β1 and Smad2 is a persistent biomarker of skin photoaging, while the increased expression of MMP-8 in keratinocytes can be regarded as a marker of acute sun exposure.
authors.affiliation: Department of Dermatology, Medical University of Lodz, Poland. lesiak_ola@interia.pl.
authors.forename: Aleksandra
authors.initials: A
authors.lastname: Lesiak
authors.forename: Michal
authors.initials: M
authors.lastname: Rogowski-Tylman
authors.forename: Marian
authors.initials: M
authors.lastname: Danilewicz
authors.forename: Anna
authors.initials: A
authors.lastname: Wozniacka
authors.forename: Joanna
authors.initials: J
authors.lastname: Narbutt
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D004249:DNA Damage; D006693:Holidays; D006801:Humans; D008297:Male; D020784:Matrix Metalloproteinase 8 / Q000096:biosynthesis; D008875:Middle Aged; D012867:Skin / Q000378:metabolism* / Q000473:pathology / Q000528:radiation effects*; D015595:Skin Aging / Q000473:pathology / Q000502:physiology*; D012871:Skin Diseases / Q000209:etiology / Q000378:metabolism / Q000473:pathology; D051899:Smad2 Protein / Q000096:biosynthesis; D013030:Spain; D055108:Sunbathing / Q000293:injuries; D013472:Sunlight / Q000009:adverse effects; D016212:Transforming Growth Factor beta / Q000096:biosynthesis; D053773:Transforming Growth Factor beta1 / Q000096:biosynthesis; D055815:Young Adult
chemical_list: D015415:Biomarkers; C497782:SMAD2 protein, human; D051899:Smad2 Protein; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; C488762:MMP8 protein, human; D020784:Matrix Metalloproteinase 8
keywords: IHC; MMP-8; Smad2; TGF-β1; photoaging; short and long UVR exposure