Aging research is booming. So much so that some no longer see it as an inevitable process, but as a disease that can therefore be treated. This is particularly the opinion, in the United States, of some scientists, including Professor David A. Sinclair, geneticist specializing in aging, author of the book “Why we age and why it is not inevitable” (ed. quantity). If the pill that will make us look younger is not yet on the program, knowledge of the processes of senescence, that is to say the degradation of cell functions, is being refined and makes it possible to develop strategies to slow them down. In particular, we are witnessing a paradigm shift concerning the skin. “We have long believed that aging, general but also cutaneous, was linked to a slowdown in metabolism, to a lack of production of young cells, explains Cyrille Telinge, founder of the cosmetics brand Novexpert. What appears rather today is that the cells manufactured are made with errors, aging appears as an accumulation of defects. The consequence is that we seek less to stimulate to produce more than to manufacture good quality products. » We take stock of the progress of knowledge and their cosmetic applications to fight against sagging skin.
Did you say zombies?
A good ten years ago, the concept of zombie cells emerged, old and damaged cells which do not want to die, which roam the tissues and disrupt their functioning. “We find them everywhere in the body, in the bones, the cartilage, the brain, and we are beginning to realize that they play an important role in many degenerative pathologies, underlines Patrick Bogdanowicz, researcher in biology of aging at the within the Pierre Fabre group, notably for the Avène brand. They are not numerous, but as they send a lot of deleterious signals, they have an impact on all the tissues. These cells are not eliminated for two reasons. Normally, when a cell is very altered by external attacks, or simply when it is old, it is destroyed. Either it destroys itself, or it sends inflammatory signals that command the immune system to eliminate it. “When the cells do not want to self-destruct, or when their inflammatory signal is not detected, they become zombies”, explains Cyrille Telinge. This destabilizes the skin, because not only are they no longer useful – they no longer replicate – but, in addition, they cause problems because of the messages they send, what scientists call SMS for senescence-messaging. secretome. What are the consequences for the firmness of the skin? In the dermis, these zombie cells are senescent fibroblasts, and the messages they send disrupt the production of collagen. They produce enzymes, MMPs (matrix metalloproteases), which destroy this fiber, the main protein of the skin. If the latter are necessary, especially for the healing process, in excess, they become problematic.
The youth parade
Medical research goes straight to the point, it works on molecules that can destroy these deleterious cells. Clinical studies are in progress in particular concerning osteoarthritis and certain degenerative diseases of the brain. In the cosmetics sector, the answers vary. At Chanel, it is a natural enzymatic active which would increase the elimination by the skin of these fibroblasts which have become undesirable. “At Avène, we try to block the text messages sent to bypass the zombie cells in their environment and make them harmless. At high doses, niacinamide (vitamin B3) has been shown to be very effective. It also slows down the appearance of senescent cells,” explains Patrick Bogdanowicz. Concrete result: collagen is less degraded. Another approach which interests both fundamental research and cosmetics is to act on the natural systems which allow a cell not to become senescent too quickly. How does it work? A cell can itself degrade the waste it produces, this is called autophagy, and it is this process that increases its longevity. “Studies conducted on residents of Okinawa, Japan, where there is one of the highest rates of centenarians in the world and one of the lowest rates of metabolic diseases, have shown that the SIRT1 gene – activated in them, while it is not for most of us – allowed their cells to self-cleanse regularly. And therefore to age less quickly. In cosmetics, we have the ability to boost autophagy, via molecules that target this famous gene,” explains Cyrille Telinge. Our brand (Novexpert) has shown via in vitro study that its patented complex Novaxyline can reduce the number of zombie cells by activating the SIRT1 gene.
Other tough approaches
In partnership with Inserm, Clarins has demonstrated that, with the drop in estrogen at menopause, not only do the fibroblasts produce less collagen, but they also lose tensile strength, that is to say the ability to keep the collagen fibers taut, which, as a result, organize themselves no matter How? ‘Or’ What. The aim here is therefore to remuscle the fibroblasts so that they ensure this tensioning. Property shown by gorse extract. This discovery is in line with current knowledge on the fibroblast. “It was long believed that their number decreased over the years, but it is above all that they are exhausted, their activity decreases by 32% between 29 and 80 years old”, underlines Cyrille Telinge. Among the advances that bring beads to cosmetics: the discovery of a new collagen. Until now, the labs focused on collagen III, the one that makes the skin plump and disappears the fastest over the years (at 50, we have lost 50%), and on collagen I, which ensures the structure. Today, a newcomer is making headlines in research on the aging of the skin (and hair), collagen XVII. “It acts on the renewal of keratinocytes, it is therefore involved in smoothing and especially the thickness of the skin. On the other hand, it promotes a good junction between the epidermis and the dermis, an element as essential to firm skin as the density of the dermis”, explains Cyrille Telinge. If we compare the skin to a mattress, it is the idea that the foam of the superficial layer must be well attached to the springs below. Vitamin C, silicon, peptides, retinol, hyaluronic acid… It is up to the labs to test whether the star active ingredients in collagen synthesis also have an impact on this newcomer. To be continued…