Research on aging is booming. So much so that some no longer see it as an inevitable process, but as a disease that can therefore be cured. This is in particular 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 because it is not inevital” (ed. Quantity). If the pill that will make us look younger is not yet in the program, the knowledge of the processes of senescence, that is the degradation of cellular functions, is being refined and allows us to develop strategies to slow them down. In particular, we are witnessing a paradigm shift regarding the skin. “We have long believed that aging, general but also cutaneous, was linked to a slowdown in metabolism, a lack of production of young cells”, explains Cyrille Telinge, founder of the Novexpert cosmetics brand. What appears rather today is that manufactured cells are made with errors, aging appears as an accumulation of defects. The consequence is that we seek less to encourage people to produce than to produce good quality products. We take stock of the progress of knowledge and its cosmetic applications to combat sagging skin.
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Did you say zombies?
Ten years ago, the concept of zombie cells emerged, old and damaged cells that don’t want to die, that roam the tissues and stop their functioning. “We find them everywhere in the body, in the bones, in the cartilage, in the brain, and we are beginning to understand that they play an important role in many degenerative diseases,” emphasizes Patrick Bogdanowicz, researcher in the biology of aging at the Pierre Fabre group, in particular for the Avène brand. They are not numerous, but because they send out many deleterious signals, they impact all tissues. These cells are not eliminated for two reasons. Normally, when a cell is greatly altered by external attacks, or simply when it is old, it is destroyed. It either destroys itself or sends inflammatory signals that command the immune system to kill it. “When cells don’t want to self-destruct, or when their inflammatory signal isn’t detected, they become zombies,” says Cyrille Telinge. This destabilizes the skin, because not only are they no longer useful – they no longer replicate – but, in addition, they cause problems due to the messages they send, what scientists call senescence-secretion SMS. What are the consequences for the firmness of the skin? In the dermis, these zombie cells are senescent fibroblasts, and the messages they send stop collagen production. They produce enzymes, the MMPs (matrix metalloproteases), which destroy this fiber, the main protein in the skin. If the latter are needed, especially for the healing process, in excess, they become problematic.
The parade of young people
Medical research goes straight to the point, it works on molecules that can destroy these deleterious cells. Clinical studies are underway in particular on arthrosis and on some degenerative diseases of the brain. In the cosmetics sector, the answers vary. In Chanel it is a natural enzymatic active that would increase the elimination by the skin of these fibroblasts that have become undesirable. “At Avène, we try to block text messages sent to bypass the zombie cells in their environment and render them harmless. In 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 that affects both fundamental research and cosmetics is to act on natural systems that 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-clean regularly. less quickly. In cosmetics, we have the ability to increase autophagy, through molecules that target this famous gene, “explains Cyrille Telinge. Our brand (Novexpert) has shown in an in vitro study that its patented Novaxyline complex can reduce the number of zombie cells by activating the SIRT1 gene.
Other difficult approaches
In collaboration with Inserm, Clarins has shown that, with the decline in estrogen in menopause, fibroblasts not only produce less collagen, but also lose their tensile strength, i.e. the ability to keep collagen fibers taut, which suddenly organize themselves to random. The purpose here is therefore to re-muscle the fibroblasts so that they ensure this tensioning. Property shown by the extract of gorse. This finding is in line with current fibroblast knowledge. “It has long been believed that their number has decreased over the years, but it is above all that they are exhausted, their activity decreases by 32% between the ages of 29 and 80,” points out Cyrille Telinge. Among the advances that lead beads to cosmetics: the discovery of a new collagen. Until now, laboratories have focused on collagen III, which makes the skin plump and disappears faster over the years (at 50 we lost 50%), and on collagen I, which ensures its structure. Today, a newcomer is making headlines in research on aging skin (and hair), collagen XVII. “It acts on the renewal of keratinocytes, is therefore involved in smoothing and above all in the thickness of the skin. Instead, it favors a good junction between the epidermis and the dermis, an essential element for firming the skin as much as the density of the dermis ”, explains Cyrille Telinge. If we compare the skin with a mattress, it is the idea that the foam of the surface layer must be well adhered to the underlying springs. Vitamin C, silicon, peptides, retinol, hyaluronic acid … It is up to the laboratories to verify whether the most important active ingredients in the synthesis of collagen have an impact on this newcomer as well. Keep on…
