In skin, the dermal epidermal junction (DEJ) is the layer responsible for supporting the epidermis and for the communication between epidermal and dermal cells. Traditionally, the study of the mechanisms of skin aging has overlooked this important area. The DEJ is physically a basement membrane that separates the skin cells in the epidermis from the extracellular matrix (ECM) which lies below, in the dermis. This membrane is composed of two layers, the basal lamina, in contact with the cells, and the underlying reticular lamina, in contact with the ECM. The basal lamina is rich in collagen type IV, proteoglycans and the glycoproteins entactin and laminin. These molecules provide a structural network and bioadhesive properties for cell attachment.
Laminin is a glycoprotein of about 850 kDa and it is, after collagen, the most abundant protein in the ECM. However, while Collagen performs exclusively a structural role in the skin, Laminin is involved in functionalisation and activation of cells, in processes such as cell proliferation, migration and adhesion. These mechanisms are necessary to keep the normal balance of the skin and are essential for processes as important as wound healing, for instance. Laminin only exists in basement membranes. It is composed of three very long polypeptide chains (alpha, beta and gamma) arranged in the shape of an assymetric cross and held together by disulfide bonds. The three chains exist as different subtypes which results in twelve different isoforms for laminin, of which the best well studied is Laminin-1.
Keratinocytes recognise the binding domains on Laminin, particularly Laminin-5, by using their own integrin receptors, transmembrane proteins located on specific junction points called hemidesmosomes.
Lipotec has identified and synthesized a sequence from the alpha chain of Laminin: a hexapeptide named Serilesine®. This peptide retains many of the chracteristics of the native protein, and promotes cell adhesion and proliferation. Certain features of the DEJ are altered by the aging process, such as the anchoring ability of keratinocytes, probably due to deficiencies in the expression of integrins as we age.
Laminin-5 synthesis has also been proved to decrease in aged skin. This causes a loss of contact between dermis and epidermis, and results in the skin losing elasticity and becoming saggy. The cohesion between dermis and epidermis is essential to maintain skin balance because it enables the transport of oxygen, nutrients and waste, contributing to the health of the epidermis. Serilesine's synthetic hexapeptide from Laminin-1 is able to restore the skin’s normal function by promoting synthesis of Laminin-5, stimulating keratinocyte and fibroblast proliferation, inducing a redensifying effect on the dermis, and an improvement in skin elasticity, compactness, tonicity and smoothness.
COSMETIC BENEFITS
- Improves cell adhesion by enhancing synthesis of laminin-5
- Adhesion of cells to the basement membrane and among themselves provides firmness to the skin
- Increased contact between skin cells ensures correct nourishment and health
- Induces a significant increase in dermis density, improving skin compactness
Active 0.5% Hexapeptide-10
Serilesine® Solution GCC can be incorporated at the final stage of the manufacturing process, provided the temperature is below 40°C (104°F). Taking into consideration the concentration of peptide in Serilesine® Solution GC, it is recommended that 1 - 10% of the solution be present in the final formulation in order to obtain significant restructuring activity.
INCI: Water (and) Hexapeptide-10