title: Structure and function of human stratum corneum under deformation.
abstract: BACKGROUND
  The stratum corneum (SC) has an important barrier function. The effect of a mechanical stress applied to the SC is controversial on this important physiological parameter.
  
  
  OBJECTIVE
  To assess both in vitro and in vivo the structure and function of human SC submitted to controlled strains, we measured the transepidermal water loss (TEWL), in vivo, on human skin submitted to controlled strains ranging from 0 to 20% extension imposed by a Densi-score device. We also looked at the structure of the SC by means of X-ray diffraction and transmission electron microscopy.
  
  
  RESULTS
  Transmission electron microscopy and X-ray diffraction analysis were performed on harvested and stretched human SC. TEWL was not significantly influenced by the relative deformation applied to the skin. At high strain (60%) imposed in vitro to the SC, lipid bilayers and corneosomes were detached from corneocytes. Only rare corneosomes showed internal disruption. X-ray analysis did not reveal modifications in the supramolecular organization of intercellular lipids while stretching the SC.
  
  
  CONCLUSIONS
  Submitting human SC to an extension force up to 20% elongation does not significantly alter the barrier function.
authors.affiliation: L'Oréal Recherche, Centre Charles-Zviak, Clichy, France. jlleveque@recherche.loreal.com
authors.forename: Jean-Luc
authors.initials: JL
authors.lastname: Lévêque
authors.forename: Philippe
authors.initials: P
authors.lastname: Hallégot
authors.forename: Jean
authors.initials: J
authors.lastname: Doucet
authors.forename: Gérald
authors.initials: G
authors.lastname: Piérard
mesh_terms: D000328:Adult; D001834:Body Water / Q000378:metabolism; D002463:Cell Membrane Permeability; D046508:Culture Techniques; D004817:Epidermis / Q000378:metabolism* / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D011336:Probability; D012016:Reference Values; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D014870:Water Loss, Insensible / Q000502:physiology*; D014961:X-Ray Diffraction
chemical_list: D008563:Membrane Lipids