Stratum corneum lipids and structural proteins (SC barrier)

The stratum corneum (SC) is the outermost layer of the epidermis, serving as the body's primary interface with the environment and its main permeability barrier (StatPearls, 2023 [1]). It is characterized by a brick and mortar structure where protein-rich corneocytes (the bricks) are embedded in a continuous matrix of intercellular lipids (the mortar) (Journal of Clinical and Aesthetic Dermatology, 2014 [2]). Key structural proteins include filaggrin, loricrin, and involucrin, which form the cornified envelope, while the lipid matrix is composed of a precise ratio of ceramides, cholesterol, and free fatty acids (PubMed, 2018 [3]). This complex maintains skin hydration by preventing transepidermal water loss (TEWL) and provides a robust defense against pathogenic microorganisms and chemical irritants (International Journal of Molecular Sciences, 2020 [4]). Defects in these components, such as filaggrin mutations or altered ceramide profiles, are central to the pathogenesis of inflammatory skin diseases like atopic dermatitis and psoriasis (British Journal of Dermatology, 2019 [5]). Therapeutic interventions target this barrier through the application of emollient lipids, humectants, and barrier-repair formulations designed to mimic the natural composition of the SC (Dermatologic Therapy, 2020 [6]).

Other names

Skin barrierEpidermal barrierCornified envelopeStratum corneum extracellular matrixBrick and mortar model

Restoration of the physical skin barrier through replenishment of intercellular lipids and enhancement of corneocyte hydration (StatPearls, 2023 [1]).