title: A broad spectrum high-SPF photostable sunscreen with a high UVA-PF can protect against cellular damage at high UV exposure doses.
abstract: BACKGROUND
  Advances in sunscreen technologies have yielded broad spectrum sunscreens at high-sun protection factor (SPF) and ultraviolet A protection factor (UVA-PF) levels that are photostable and powerful in protecting skin from erythema. Questions arise whether these sunscreens protect proportionally against cellular skin damage caused by high ultraviolet exposures.
  
  
  OBJECTIVE
  The objective of this study is to evaluate if high-SPF sunscreen can protect skin at a cellular level under UV exposure doses [>50 minimal erythema dose (MED)] similarly to the SPF value.
  
  
  METHODS
  Sunburn cells, Langerhans cells, thymine dimers, protein 53 (p53), and matrix metalloproteinase (MMP)-1 and MMP-9 endpoints were evaluated in biopsies from 12 subjects following four treatments: unprotected exposed to 0, 1 and 3 MED and sunscreen (SPF 55) protected exposed to 55 MED of UV radiation.
  
  
  RESULTS
  All the markers showed significantly more damage for the 3 MED-untreated sites when compared with non-irradiated control, and majority of the markers showed marked damage following unprotected 1 MED exposure. After 55 MEDs, sunscreen-protected sites showed significantly less p53 and MMP-9 (keratinocyte) staining than the 1 MED-exposed unprotected sites, while all the other biomarkers in sunscreen protected sites showed no statistical differences from 1 MED-exposed unprotected sites.
  
  
  CONCLUSIONS
  A high-SPF photostable sunscreen with high UVA-PF can provide proportionately high protection against multiple cellular damage markers.
authors.affiliation: Johnson & Johnson Consumer and Personal Products Inc., Skillman, NJ, USA.
authors.forename: Curtis
authors.initials: C
authors.lastname: Cole
authors.forename: Yohini
authors.initials: Y
authors.lastname: Appa
authors.forename: Hao
authors.initials: H
authors.lastname: Ou-Yang
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000378:metabolism; D004890:Erythema / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D005260:Female; D006801:Humans; D007801:Langerhans Cells / Q000378:metabolism* / Q000473:pathology; D008297:Male; D020781:Matrix Metalloproteinase 1 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D008875:Middle Aged; D011740:Pyrimidine Dimers / Q000378:metabolism; D012867:Skin / Q000378:metabolism* / Q000473:pathology; D059405:Sun Protection Factor; D013473:Sunscreening Agents; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D015415:Biomarkers; D011740:Pyrimidine Dimers; D013473:Sunscreening Agents; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; C522360:MMP1 protein, human; D020781:Matrix Metalloproteinase 1
keywords: Langerhans cell; biomarkers; biopsy; erythema; matrix metalloproteinases; minimal erythema dose; p53; sunburn cell; thymine dimer