Ceramides and Skin Function

Abstract

Ceramides are the major lipid constituent of lamellar sheets present in the intercellular spaces of the stratum corneum. These lamellar sheets are thought to provide the barrier property of the epidermis. It is generally accepted that the intercellular lipid domain is composed of approximately equimolar concentrations of free fatty acids, cholesterol, and ceramides. Ceramides are a structurally heterogeneous and complex group of sphingolipids containing derivatives of sphingosine bases in amide linkage with a variety of fatty acids. Differences in chain length, type and extent of hydroxylation, saturation etc. are responsible for the heterogeneity of the epidermal sphingolipids. It is well known that ceramides play an essential role in structuring and maintaining the water permeability barrier function of the skin. In conjunction with the other stratum corneum lipids, they form ordered structures. An essential factor is the physical state of the lipid chains in the nonpolar regions of the bilayers. The stratum corneum intercellular lipid lamellae, the aliphatic chains in the ceramides and the fatty acids are mostly straight long-chain saturated compounds with a high melting point and a small polar head group. This means that at physiological temperatures, the lipid chains are mostly in a solid crystalline or gel state, which exhibits low lateral diffusional properties and is less permeable than the state of liquid crystalline membranes, which are present at higher temperatures. The link between skin disorders and changes in barrier lipid composition, especially in ceramides, is difficult to prove because of the many variables involved. However, most skin disorders that have a diminished barrier function present a decrease in total ceramide content with some differences in the ceramide pattern. Formulations containing lipids identical to those in skin and, in particular, some ceramide supplementation could improve disturbed skin conditions. Incomplete lipid mixtures yield abnormal lamellar body contents, and disorder intercellular lamellae, whereas complete lipid mixtures result in normal lamellar bodies and intercellular bilayers. The utilization of physiological lipids according to these parameters have potential as new forms of topical therapy for dermatoses. An alternative strategy to improving barrier function by topical application of the various mature lipid species is to enhance the natural lipid-synthetic capability of the epidermis through the topical delivery of lipid precursors.

Quantitative study of stratum corneum ceramides contents in patients with sensitive skin

“…Major components of intercorneocyte lipids are ceramides, cholesterol and fatty acids, and it has been reported that ceramides play the essential role among them. 3,4 Skin diseases can cause abnormalities in the formation of intercorneocyte lipids. In particular, there have been reports of decreased ceramides in the stratum corneum in skin diseases with a damaged skin barrier, such as atopic dermatitis, 5,6 psoriasis 7 and ichthyosis.…”

“…Ceramides are a structurally heterogeneous and complex group of sphingolipids containing derivatives of sphingosine bases in amide linkage with a variety of fatty acids with 24-26 carbon links. 4,32 Inside a cell, it has been reported that ceramides act as secondary signal transmitters and participate in the lipid signal paths in mammal cells, and induce cell proliferation and differentiation, restraint of cell cycle and apoptosis as major responses of intra-cell reaction to external stimulation. 33,34 Stratum corneum ceramides are heterogeneous compound mixtures.…”

Reliability of fourier transform infrared spectroscopy in the characterization of human skin

“…The FT-IR spectroscopy band in the 1738 -1646 cm -1 region originates from: the C=O stretch of monosubstituted amides like those found in N-acetylated GAG's [3], protein backbone (Protein Amide I) [6], ceramides [20], phospholipid esters [21] and the −COOH asymmetric vibrations [1]. Figure 2 shows the standard curve of the DS band in the 1738 -1646 cm -1 region that was used to quantify the corresponding FT-IR bands on the spectra of human skin (Figure 1).…”

“…The area of this band decreased by 35.60% (w/w) in the older group ( Table 1). Such band is made out of contributions from molecules known to increase with age like proteins [22], and from reactive carbonyl compounds that are believed to cause "the carbonyl stress" [23], minus reductions from molecules that decreased, such as GAG-N-acetyl groups [5,18] ceramides [20], and phospholipids [21]. The 35.60% (w/w) decrease of band intensity at 1738 -1646 cm -1 in the older group, indicates that there were more losses than gains in the number of molecules containing functional groups that absorb IR light in this region.…”

Influence of ceramide 2 on in vitro skin permeation and retention of 5-ALA and its ester derivatives, for Photodynamic Therapy

“…It has been postulated (Coderch et al, 2003;Bouwstra, Ponec, 2006) that formulations containing lipids identical to those in skin, in particular, some ceramide supplementation could have two divergent actions: (i) improve intercellular lamellae disorder or (ii) increase the skin lamellar phase, which could difficult the penetration of some drugs. These at first sight contradictory effects are dependent of the formulation that contains the ceramide.…”