Structure of lamellar lipid domains and corneocyte envelopes of murine stratum corneum. An x-ray diffraction study

Abstract

The lipid of the outermost layer of the skin is confined largely to the extracellular spaces surrounding the corneocytes of the stratum corneum where it forms a multilamellar adhesive matrix to act as the major permeability barrier of the skin. Knowledge of the molecular architecture of these intercellular domains is important for understanding various skin pathologies and their treatment, percutaneous drug delivery, and the cosmetic maintenance of the skin. We have surveyed by X-ray diffraction the structure of the intercellular domains and the extracted lipids of murine stratum corneum (SC) at 25, 45, and 70 degrees C which are temperatures in the vicinity of known thermal phase transitions [Rehfeld, S. J., & Elias, P. M. (1982) J. Invest. Dermatol. 79, 1-3]. The intercellular domains produce lamellar diffraction patterns with a Bragg spacing of 131 +/- 2 A. Lipid extracted from the SC and dispersed in excess water does not produce a simple lamellar diffraction pattern at any temperature studied, however. This and other facts suggest that another component, probably a protein, must be present to control the architecture of the intercellular lipid domains. We have also obtained diffraction patterns attributable to the protein envelopes of the corneocytes. The patterns suggest a beta-pleated sheet organizational scheme. No diffraction patterns were observed that could be attributed to keratin.

Consequences of beta-glucocerebrosidase deficiency in epidermis. Ultrastructure and permeability barrier alterations in Gaucher disease.

“…The intracellular glucosylceramide-enriched deposits in Gaucher macrophages consist of aggregates of twisted bilayers, with a bilayer width of60 A (5 1 ). In contrast, x-ray diffraction and ultrastructural studies have demonstrated that the normal lamellar spacing in normal murine and human SC is formed by two back-toback leaflets measuring _ 130 A (single leaflet = 65 A) (4,52). Whereas normal mature lamellar bilayers lack glucosylceramides ( 1, 2), the increased content ofextracellular glucosylceramides which occurs in both BrCBE-treated skin and in Gaucher mouse SC, may prevent formation of this normal repeating bilayer pattern.…”

The effect of heat on skin permeability

“…To isolate stratum corneum, the epidermis was incubated at 4 • C in a solution of 0.5% trypsin in phosphate-buffered saline (PBS; Sigma Chemical, St. Louis, MO, USA) for 12 h; rinsed with distilled water and immersed in a fresh 0.5% trypsin solution for 3 h at 38 • C; rinsed again with distilled water and dried at room temperature under vacuum (30 kPa absolute pressure) overnight; and finally stored in −70 • C freezer (White et al, 1988).…”

Studying the penetration of fatty acids into human skin by ex vivo TOF-SIMS imaging

“…Freeze-fracture [6,7] and ruthenium tetroxide post-fixation [8] electron microscopy studies revealed that lipids are arranged into bilayers [9,10]. Lipid chains tend to pack in tight lateral highly ordered packing (according to packing density: liquid < hexagonal (gel) < orthorhombic (crystalline) phases), which has been studied using atomic force microscopy [11], Fourier transformed infrared spectroscopy [12], wide-angle X-ray diffraction [13] and electron diffraction [14]. All three phases coexist, but it is believed that conformationally ordered orthorhombic packing of lipids is mainly responsible for the resistance to transdermal delivery of molecules [15].…”