Ceramides
As ceramides one calls a the lipids counting sub-group of sphingolipids . They consist of a sphingosine molecule that is bound to a fatty acid by an amide bond .
General
Ceramides occur together with other skin components in humans, among other things in the horny layer ( stratum corneum ). Due to their amphiphilic structure, they form double lipid layers and thus a natural barrier that protects the skin from drying out and prevents foreign substances from penetrating. Of malfunctioning of the balance of these substances leads to dry skin or abnormal skin conditions such as dermatitis , atopic dermatitis ( eczema ) and psoriasis ( psoriasis ).
In addition to the barrier function in the stratum corneum, ceramides also have a wide range of tasks in the rest of the organism in cell differentiation, signal transduction, apoptosis , etc.
Classes
The natural ceramides are divided into classes, which are marked with Roman numerals and differ in the chromatographic behavior of the ceramides. In addition to ceramide III, ceramide I, which is an important component of the bilayer of the stratum corneum, is also of particular importance . A newer and more common nomenclature is based on the structure of the ceramide and is based on a letter system:
| Hydroxylation of the amidated fatty acid | Sphingoid base | |
|---|---|---|
| N - N maybe hydroxylated | S - sphingosine | |
| cerium | A - A lpha-hydroxy fatty acid | P - phytosphingosine |
| O - O mega-hydroxy fatty acid | H - 6 H ydroxysphingosin |
structure
There are various options for the chain structure, which can be determined using X-ray crystallography , among other things . The three best-known structures relate to the inclusion angle α between the two chains. These include the parallel chain arrangement with α = 0 °, an angled arrangement with 0 ° <α <180 ° and the elongated shape with α = 180 °. The species occurring in each case are largely dependent on the head structure of the ceramide and contribute significantly to the behavior of the ceramide in mixed systems. That is, which lamellar spacings prevail in double-layer systems and whether the ceramide class forms gel phases, inverse hexagonal structures and the like.
Linoleic acid
Ceramide I is a compound that is structurally represented as an ester of linoleic acid . Insufficient intake of this essential fatty acid cannot produce enough ceramide I, which leads to dry, flaky skin and barrier disorders.
Biological effects
Ceramide is a central molecule in the sphingolipid metabolism, it modulates the activity of the corresponding enzymes. The consequences of this modulated enzyme activity include the inhibition of cell growth , the induction of apoptosis , the promotion of cell differentiation, cell aging and inflammatory reactions. The physiological fine-tuning and regulation of ceramide and its counterparts, such as sphingosine-1-phosphate (SPP), is likely to be of great importance for tissue homeostasis.
Effect of antidepressants on ceramides
It is currently being investigated whether there is a connection between the use of various antidepressants, etc. a. so-called selective reuptake inhibitors , and the physiological ceramide production in nerve cells exists. After seven years of research at the University of Erlangen-Nuremberg, it was discovered that the above. Group of antidepressants inhibit the formation of ceramides, which have a self-inhibiting effect on the formation of new nerve cells. Due to the increased formation of new nerve cells, antidepressants contribute to a scientifically neglected but decisive improvement in the mood of patients.
use
Ceramides are used in the form of cosmetic preparations for dry skin and for hair care. In medicine, they serve the prevention of skin disorders and medical skin care for skin diseases such as atopic dermatitis ( neurodermatitis ) and psoriasis .
Individual evidence
- ↑ S. Raudenkolb, W. Hübner u. a .: Polymorphism of ceramide 3. Part 1: an investigation focused on the head group of N-octadecanoylphytosphingosine. In: Chemistry and physics of lipids. Volume 123, Number 1, March 2003, pp. 9-17, PMID 12637161 .
- ↑ S. Motta, M. Monti u. a .: Ceramide composition of the psoriatic scale. In: Biochimica et Biophysica Acta . Volume 1182, Number 2, September 1993, pp. 147-151, PMID 8357845 .
- ↑ S. Raudenkolb: Investigations on the structural and physicochemical characterization of stratum corneum lipids and their mixed systems. Dissertation, Math.-Nat.-Tech. Faculty of the Martin Luther University Halle-Wittenberg, 2002, p. 19.
- ↑ ME Venable, JY Lee et al. a .: Role of ceramide in cellular senescence. In: The Journal of biological chemistry. Volume 270, Number 51, December 1995, pp. 30701-30708, PMID 8530509 .
- ↑ Gerit Goltz: Characterization of ceramidase inhibitors on the human keratinocyte cell line HaCaT. Dissertation, Free University of Berlin, 2002, p. 4.
- ↑ Antidepressants have surprising effects. In: welt.de . July 12, 2013, accessed September 29, 2015 .