Lamellar body mimetic system: An up-to-down repairing strategy of the stratum corneum lipid structure

Abstract

Epidermal lamellar bodies (LBs) are organelles that secrete their content, mainly lipids and enzymes, into the intercorneocyte space of the stratum corneum (SC) to form the lamellar structure of this tissue. Thus, LBs have a key role in permeability and the microbial cutaneous barrier. In this work, a complex lipid system that mimics the morphology, structure and composition of LBs has been designed. To evaluate the effect of this system on delipidized SC, in vitro experiments using porcine skin were performed. The microstructure of SC samples (native, delipidized and, delipidized after treatment) was evaluated by freeze substitution transmission electron microscopy (FSTEM) and grazing-incidence small-angle X-ray scattering (GISAXS). Delipidized SC samples showed no evidence of lipid lamellae after extraction with organic solvents. However, after treatment with the LB mimetic system, new lamellar structures between corneocytes were detected by FSTEM, and high intensity peaks and reflections were found in the GISAXS pattern. These results demonstrate a strong effect of the treatment in repairing part of the lipid lamellar structure of the SC. Accordingly, future research could extend the use of this system to repair skin barrier dysfunction.

Keywords: Freeze substitution transmission electron microscopy (FSTEM); Grazing-incidence small-angle scattering (GISAXS); Lamellar bodies (LBs); Lipid composition; Skin lipids; Stratum corneum (SC).