Corneocyte lipid envelope and extracellular lipid lamellae of the stratum corneum (CLE/ELL)

The corneocyte lipid envelope (CLE) and extracellular lipid lamellae (ELL) of the stratum corneum represent the primary physical and chemical barrier of the skin (PMID: 24635383). The CLE is a specialized structure consisting of ultra-long-chain omega-hydroxyceramides covalently bound to the cornified envelope of corneocytes, serving as a scaffold for the ELL (PMID: 22115773). The ELL is composed of a precise mixture of ceramides, cholesterol, and free fatty acids organized into lamellar phases that prevent transepidermal water loss (TEWL) and the entry of pathogens (PMID: 18306158). In diseases such as atopic dermatitis and psoriasis, the composition and organization of these lipids are significantly altered, leading to barrier dysfunction and inflammation (PMID: 30130616). Therapeutic targeting of these structures involves the topical application of physiological lipids to restore barrier integrity or the use of chemical enhancers to modulate lipid fluidity for drug delivery (PMID: 17350483). Additionally, certain drugs like PPAR agonists are investigated for their ability to stimulate the endogenous synthesis of these critical lipid components (PMID: 15930161).

Other names

Skin lipid barrierStratum corneum lipid matrixIntercellular lipid lamellaeCornified lipid envelope

Restoration of the lipid barrier through exogenous replacement of ceramides, cholesterol, and fatty acids; occlusion to reduce transepidermal water loss; and stimulation of endogenous lipid synthesis via nuclear receptor activation.