Anti-ageing
Facing an underrated skin problem
SyriCalm CLR ( PC ) from CLR Chemisches Laboratorium shows immense benefits in formulations intended for sensitive or stressed skin . Technical marketing director ,
Harald van der Hoeven discusses how the active ingredient addresses hyperosmotic stress in skin care .
To maintain its barrier properties , skin is constantly in a process of renewal . In this process the keratinocytes , which make up the epidermis , go through a continuous process of differentiation . The result is a well-established stratum corneum ( SC ), in which corneocytes are embedded in a lipid-rich matrix making the SC the actual physical barrier between the body and the outside world . The turnover time of a healthy functioning epidermis is estimated to be between two and fi ve weeks , depending on factors such as age .
The SC is extremely vulnerable to external attacks . For instance , exposure to UV light
Figure 1 : Water gradient in normal skin ( green line ) compared to that of dry skin ( red line ) or surfactants , as well as sudden changes in environmental humidity and temperature all have a negative impact on the SC ’ s quality . This not only infl uences the physical barrier properties of the skin , but also negatively affects the layers below the SC .
Keratinocytes in the stratum granulosum ( SG ) can also be affected negatively by external stresses . These are regarded as the ‘ real SC factory ’ because this is the section of the epidermis where the keratinocytes produce the precursors of the natural moisturising factors and ceramides . This is also where the keratinocytes go through a keratinisation process where they metamorphose into corneocytes . These processes are all fundamentally important in building up a strong SC .
It is crucial to maintain the quality and activity of the keratinocytes in the SG . In this context , one specifi c property of these cells demands special attention – namely cellular volume . This is essential for cellular functioning . Negative external infl uences directly and indirectly induce hyperosmotic stress , and hence the loss of cellular volume in the epidermis .
Figure 2 : The assessment of taurine effl ux and the effect of SyriCalm CLR ( PC )
What is hyperosmotic stress ?
This phenomenon can affect keratinocytes in the SG . While the SG has a steep water gradient , SC disruption leads to an increase in water loss and volume degradation of these cells ( see Figure 1 ). At the border between the stratum spinosum and SG , the cells start to lose water . The intracellular water concentration reaches about 40 percent at the border between SG and SC , while at the surface of the skin the cells contain 15 to 30 percent water . This extreme loss of intracellular water in the SG is part of the regular differentiation process .
Hyperosmotically stressed skin shows a signifi cantly elevated loss of intracellular water depicted by the red line in Figure 1 . External stresses lead to an elevated loss of cellular water in the SG . A disruption of its quality – an abundant phenomenon caused by external stress – leads to the drying out of the SC . This is where the corneocytes start absorbing water from the SG . Another cause of hyperosmotic stress is the penetration of electrolytes into the skin , causing keratinocytes to try and
16 | MAY 2017 | P C Review