title: Harmful effects of UVA on the structure and barrier function of engineered human cutaneous tissues.
abstract: OBJECTIVE
  To investigate the effects of a single UVA exposure on engineered human cutaneous tissues.
  
  
  METHODS
  Skin equivalents (SE) were obtained by culturing keratinocytes on fibroblast-populated collagen gels; epidermal equivalents (EE) were obtained by seeding keratinocytes on non-populated collagen gels. After maturation and differentiation of the epidermis, SE and EE were exposed to 50 or 100 J/cm2 UVA. Structural damage and total epidermal lipids were analysed and diffusion of radioactive oestradiol was monitored 24 and 72h post-irradiation.
  
  
  RESULTS
  Twenty-four hours after UVA irradiation, a disorganization of the living epidermis is observed. UVA also significantly reduced the skin barrier function and led to an increase in phospholipid and in a decrease of ceramide levels. However, both the structure and the barrier function of SE were recovered 72 h post-irradiation, thereby suggesting that an intrinsic repair process might exist within the irradiated SE.
  
  
  CONCLUSIONS
  This study provides a strong evidence that UVA radiation alters both the epidermal and dermal structures, the synthesis of epidermal lipids, and the permeability of the human skin.
authors: Département de Chirurgie, Université Laval, Québec, Canada.
authors: M
authors: M
authors: Robert
authors: V
authors: V
authors: Bissonauth
authors: G
authors: G
authors: Ross
authors: M
authors: M
authors: Rouabhia
mesh_terms: D002478:Cells, Cultured; D005347:Fibroblasts / Q000378:metabolism / Q000528:radiation effects; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism / Q000528:radiation effects; D050356:Lipid Metabolism; D008055:Lipids / Q000096:biosynthesis; D012867:Skin / Q000033:anatomy & histology / Q000378:metabolism / Q000528:radiation effects; D012869:Skin Absorption / Q000528:radiation effects; D012879:Skin Physiological Phenomena / Q000528:radiation effects*; D017768:Skin, Artificial; D014466:Ultraviolet Rays / Q000009:adverse effects*
chemical_list: D008055:Lipids