Atopic Dermatitis: a Short Summary
Ceramides are part of the 3 main lipid types in the skin:
- ceramide
- backbone:long aminoalcohol chain (C16-24)= cer (sphingoid base + fatty acid)
- 12 types identified
- cholesterol
- free fatty acids
Roles of lipids in the skin
- constituents of cell membranes (plasma, cellular organelle)
- lipid droplets (adipocytes in fat and sequestration of toxic lipids (protection from cell death)
- epidermal barrier
- essential for survival
- lipids unique to skin
- epidermal permeability barrier lipids
- the epidermal barrier is located in the stratum corneum SC in lamellar structures (lamellar bodies)
Synthesis of ceramides (and epidermal lipids in general)
- lipid synthesis in the stratum granulosum (SG)
- lipid packaging (between the SG and the stratum corneum (SC))
- lipid secretion and processing in the SC
Diseases related to anomalies in the synthesis of epidermal lipids in general (of which ceramides are a part of)
- Atopic Dermatitis
- anomalies in lipid processing (strtum corneum) and ceramide (lipid) synthesis (stratum granulosum)
- Harlequin ichtyosis and lamellar ichtyosis
- anomalies in lipid packaging (location between stratum granulosum and stratum corneum)
- Gaucher and Niemann-Pick Diseases
- anomalies in lipid processing (location in the stratum corneum)
Role of ceramides in the skin
- Structural roles:
- constitute the backbone structure of sphingolipids
- components of cell membranes
- epidermal permeability barrier function
- role in intracellular signaling
- accumulation results in cell cycle arrest
- regulation of cell differentiation
- regulation of apoptosis/autophagy
- role in immunity
- more precisely in innate immunity: induce antimicrobial peptide production
Contributors:
Dr Christophe HSU – dermatologist. Geneva, Switzerland
Source de l’Information. Uchida Y. The unique feature of epidermal barrier lipid formation. Investigative Dermatology (IID) 2013 – Edinburgh, United Kingdom (UK).
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