title: Comparative immunohistochemical assessment of cutaneous cyclooxygenase-2 enzyme expression in chronological aging and photoaging.
abstract: OBJECTIVE
  Skin aging can be classified into chronological aging and photoaging. Cyclooxygenase-2 (COX-2) may be involved in ultraviolet-induced inflammation, photocarcinogenesis and the aging process. Studies done focused on assessing COX-2 expression after acute ultraviolet exposure and in photocarcinogenesis. Comparative assessment of COX-2 expression in chronological aging and photoaging was not previously studied. We aimed to compare COX-2 expression in chronological aging and photoaging.
  
  
  METHODS
  Sixty participants were included (20 with chronological aging, 20 with photoaging, and 20 non-skin-aged contributors as controls). Fitzpatrick skin type and Glogau's photoaging type were assessed. Immunohistochemical evaluation of COX-2 was done in biopsies from sun-protected skin in the chronological aging and control groups, and from sun-exposed skin in the photoaging group.
  
  
  RESULTS
  Comparison between each two groups showed a high statistically significant difference, with the highest percentage of mild, moderate and marked expression in the control, chronological aging and photoaging groups, respectively. A high statistically significant positive correlation was found between grading of solar elastosis in the photoaging group and COX-2 expression parameters.
  
  
  CONCLUSIONS
  COX-2 expression is significantly higher in chronologically aged and photoaged skin than the normal young skin. This level of expression is significantly higher in photoaging than in chronological aging. COX-2 expression is positively related with the degree of solar elastosis in photoaging.
authors.affiliation: Department of Dermatology and Venereology, Ain Shams University, Cairo, Egypt.
authors.forename: Mohammed Ahmad
authors.initials: MA
authors.lastname: Habib
authors.forename: Samar Abdallah M
authors.initials: SA
authors.lastname: Salem
authors.forename: Sarah Adel
authors.initials: SA
authors.lastname: Hakim
authors.forename: Yahia Ahmad Mostafa
authors.initials: YA
authors.lastname: Shalan
mesh_terms: D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D012867:Skin / Q000201:enzymology*; D015595:Skin Aging; D055815:Young Adult
chemical_list: D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human
keywords: chronological aging; cyclooxygenase-2 (COX-2); photoaging