Stratum corneum proteins and lipids (SC proteins and lipids)

The stratum corneum (SC) is the outermost layer of the epidermis, serving as the body's primary interface with the environment and providing a vital permeability barrier (StatPearls, 2023). It is structurally organized according to a "brick and mortar" model, where keratin-filled corneocytes are surrounded by a complex matrix of intercellular lipids (PubMed, PMID: 18254808). The protein component includes filaggrin, which is processed into natural moisturizing factors (NMFs), and structural proteins like loricrin and involucrin that form the cornified envelope (Journal of Investigative Dermatology, 2012). The lipid matrix consists of a precise mixture of ceramides, cholesterol, and free fatty acids, which are essential for preventing transepidermal water loss (TEWL) (JCI, 2004). Deficiencies or alterations in these proteins and lipids are central to the pathogenesis of skin disorders such as atopic dermatitis, psoriasis, and various forms of ichthyosis (International Journal of Molecular Sciences, 2018). Pharmacological interventions often target this layer through the application of topical emollients, humectants, and barrier-repair formulations containing physiological lipids. Additionally, keratolytic agents like salicylic acid or urea are used to modulate the desquamation process by breaking down protein links between corneocytes. Maintaining the integrity of the stratum corneum is crucial for preventing systemic absorption of environmental toxins and protecting against microbial invasion.

Other names

Skin barrierCornified envelopeIntercellular lipid matrixEpidermal barrier

Restoration of the epidermal permeability barrier through lipid replenishment, hydration of the cornified layer, and modulation of corneocyte cohesion and desquamation.