New insights into skin structure: scratching the surface.

The formation, structural organization, and barrier functions of stratum corneum (SC) are reviewed. Stratum corneum is considered as a composite material and a biopolymer with properties so unique as to consider it a 'smart material'. SC, together with stratum granulosum (SG) responds (as an actively smart material) to environmental signals with appropriate modulations in its barrier properties. Current theories on the mode of barrier formation, validity of use of animal models and ex vivo human skin in studies of percutaneous absorption, as well as its implications in development of transdermal systems (TDS) are discussed. Potential pitfalls in extrapolating from animal data and the use of cadaver skin/epidermal membranes in evaluations of TDS are also stressed.

[1]  R. Chilcott,et al.  Transepidermal water loss does not correlate with skin barrier function in vitro. , 2002, The Journal of investigative dermatology.

[2]  P. Elias,et al.  Structural and lipid biochemical correlates of the epidermal permeability barrier. , 1991, Advances in lipid research.

[3]  L. Packer,et al.  Sebaceous gland secretion is a major physiologic route of vitamin E delivery to skin. , 1999, The Journal of investigative dermatology.

[4]  S. Friberg,et al.  Water permeation of reaggregated stratum corneum with model lipids. , 1990, The Journal of investigative dermatology.

[5]  R. Warner,et al.  Water disrupts stratum corneum lipid lamellae: damage is similar to surfactants. , 1999, The Journal of investigative dermatology.

[6]  I. Leigh.  The Keratinocyte handbook , 1994 .

[7]  J. Bouwstra,et al.  The role of ceramide composition in the lipid organisation of the skin barrier. , 1999, Biochimica et biophysica acta.

[8]  L. Norlén,et al.  Skin barrier structure and function: the single gel phase model. , 2001, The Journal of investigative dermatology.

[9]  P. Elias,et al.  Omega-hydroxyceramides are required for corneocyte lipid envelope (CLE) formation and normal epidermal permeability barrier function. , 2000, The Journal of investigative dermatology.

[10]  M. Denda,et al.  Immobilization‐induced and crowded environment‐induced stress delay barrier recovery in murine skin , 1998, The British journal of dermatology.

[11]  U. Rassner,et al.  The secretory granular cell: the outermost granular cell as a specialized secretory cell. , 1998, The journal of investigative dermatology. Symposium proceedings.

[12]  R. Paoletti,et al.  Advances in Lipid Research , 1988 .

[13]  H. Junginger,et al.  Structure of fully hydrated human stratum corneum: a freeze-fracture electron microscopy study. , 1996, The Journal of investigative dermatology.

[14]  W. Cunliffe,et al.  Human beta defensin-1 and -2 expression in human pilosebaceous units: upregulation in acne vulgaris lesions. , 2001, The Journal of investigative dermatology.

[15]  Reply: Letters to the Editor , 2001 .

[16]  W. Scherbaum,et al.  Corticotropin-releasing hormone: An autocrine hormone that promotes lipogenesis in human sebocytes , 2002, Proceedings of the National Academy of Sciences of the United States of America.

[17]  B. Forslind.  A domain mosaic model of the skin barrier. , 1994, Acta dermato-venereologica.

[18]  C. Chuong,et al.  What is the 'true' function of skin? , 2002, Experimental dermatology.

[19]  J. Bouwstra,et al.  Does the single gel phase exist in stratum corneum? , 2002, The Journal of investigative dermatology.

[20]  L. Goldsmith.  Physiology, biochemistry, and molecular biology of the skin , 1991 .

[21]  M. Bloom,et al.  A model membrane approach to the epidermal permeability barrier. , 1994, Biochemistry.

[22]  P. Elias,et al.  Isolation and lipid biochemical characterization of stratum corneum membrane complexes: implications for the cutaneous permeability barrier. , 1982, The Journal of investigative dermatology.

[23]  P. Elias,et al.  Ionic calcium reservoirs in mammalian epidermis: ultrastructural localization by ion-capture cytochemistry. , 1985, The Journal of investigative dermatology.

[24]  P. Elias,et al.  From basket weave to barrier. Unifying concepts for the pathogenesis of the disorders of cornification. , 1993, Archives of dermatology.

[25]  Karen Holbrook,et al.  Calcium regulation of growth and differentiation of mouse epidermal cells in culture , 1980, Cell.

[26]  A V Rawlings,et al.  Stratum corneum moisturization at the molecular level. , 1994, The Journal of investigative dermatology.

[27]  M. Visscher,et al.  Skin Science and the Future of Dermatology , 1998, Journal of cutaneous medicine and surgery.

[28]  R. Ghadially,et al.  Morphology of lipid alterations in the epidermis: A review , 1997, Microscopy research and technique.