title: Prolonged viability of human organotypic skin explant in culture method (hOSEC).
abstract: BACKGROUND
  Currently, the cosmetic industry is overwhelmed in keeping up with the safety assessment of the increasing number of new products entering the market. To meet such demand, research centers have explored alternative methods to animal testing and also the large number of volunteers necessary for preclinical and clinical tests.
  
  
  OBJECTIVE
  This work describes the human skin ex-vivo model (hOSEC: Human Organotypic Skin Explant Culture) as an alternative to test the effectiveness of cosmetics and demonstrate its viability through cutaneous keratinocytes' proliferative capacity up to 75 days in culture.
  
  
  METHODS
  The skin explants obtained from surgeries were cultured in CO2-humid incubator. After 1, 7, 30 and 75 days in culture, skin fragments were harvested for analysis with histomorphological exam (HE staining) on all days of follow-up and immunohistochemistry for Ck5/6, Ck10 and Ki-67 only on the 75th day.
  
  
  RESULTS
  On the 7th day, the epidermis was perfect in the dermoepidermal junction, showing the viability of the model. On the 30th day, the epidermis was thicker, with fewer layers on the stratum corneum, although the cutaneous structure was unaltered. On the 75th day, the skin became thinner but the dermoepidermal junctions were preserved and epidermal proliferation was maintained. After the 75th day on culture, the skin was similar to normal skin, expressing keratinocytes with Ck5/6 on supra-basal layers; Ck10 on differentiated layers; and viability could be assessed by the positivity of basal cells by Ki-67.
  
  
  CONCLUSIONS
  The hOSEC model seems a good alternative to animal testing; it can be used as a preclinical test analogous to clinical human skin test with similar effectiveness and viability proven by immunohistological analyses.
authors.affiliation: Universidade de São Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Marco Andrey Cipriani
authors.initials: MA
authors.lastname: Frade
authors.affiliation: Private Institute of Clinical Research and Biotechnology, Ribeirao Preto, SP, Brazil.
authors.forename: Thiago Antônio Moretti de
authors.initials: TA
authors.lastname: Andrade
authors.affiliation: Private Institute of Clinical Research and Biotechnology, Ribeirao Preto, SP, Brazil.
authors.forename: Andréia Fernanda Carvalho Leone
authors.initials: AF
authors.lastname: Aguiar
authors.affiliation: Private Institute of Clinical Research and Biotechnology, Ribeirao Preto, SP, Brazil.
authors.forename: Flávia Araújo
authors.initials: FA
authors.lastname: Guedes
authors.affiliation: Universidade de São Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Marcel Nani
authors.initials: MN
authors.lastname: Leite
authors.affiliation: Private Institute of Clinical Research and Biotechnology, Ribeirao Preto, SP, Brazil.
authors.forename: Williane Rodrigues
authors.initials: WR
authors.lastname: Passos
authors.affiliation: Universidade de São Paulo, Ribeirao Preto, SP, Brazil.
authors.forename: Eduardo Barbosa
authors.initials: EB
authors.lastname: Coelho
authors.affiliation: University of Birmingham, Birmingham, England.
authors.forename: Pranab Kummar
authors.initials: PK
authors.lastname: Das
mesh_terms: D018929:Cell Culture Techniques / Q000379:methods*; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival; D002478:Cells, Cultured; D005240:Feasibility Studies; D006801:Humans; D007150:Immunohistochemistry; D015603:Keratinocytes / Q000166:cytology* / Q000187:drug effects*; D015203:Reproducibility of Results; D012867:Skin / Q000166:cytology*; D012882:Skin Tests / Q000379:methods; D013473:Sunscreening Agents / Q000633:toxicity*; D013997:Time Factors
chemical_list: D013473:Sunscreening Agents