In recent decades, medical and technological advances have contributed to the major increase in human life expectancy. In industrialized countries, societies must now face the medical, social and economic consequences of a population pyramid that has been completely transformed by the inflation of older population groups. The significant expansion of this graying population has also created a large market for certain consumer goods that are attractive to 50- to 70-year-olds, in particular food, sporting activities, well-being, fashion and cosmetics.
SCIENCE AND AGING
Biologists, gerontologists and researchers in the pharmaceutical industry are trying to develop therapeutic strategies aimed at improving the quality of life for these aging populations. In particular, their efforts are focusing on an increase in health expectancy by trying to rid aging of its usual procession of diseases, physiological deterioration and physical or mental impairments. In recent years, significant progress has been made in understanding the biological mechanisms underlying the process of senescence. It has now been established that one of the fundamental causes of aging is the accumulation, over time, of the molecular damage inherent to our own metabolism, our genetic constitution, our life history and our environment. As a direct consequence, this molecular deterioration results in major dysfunctions within cells, organs, systems and, finally, within our body as a whole. The identification of fundamental aging mechanisms has naturally led to the elaboration and development of pharmacological means aimed at preventing, slowing down, or even repairing, certain age-related physiological alterations.
SKIN: IT REFLECTS OUR AGE AND OUR LIFE HISTORY
Among the various components of our bodies that are affected by the aging process, skin stands out. In terms of mass and surface, skin is our body’s most significant organ. It performs several essential functions, whether they are mechanical protection, waterproofing/impermeability, temperature regulation, providing a barrier against microorganisms, salt excretion, vitamin D synthesis, or the perception of tactile sensations and sexual feelings. Its appearance reflects our age and our state of health, but also our life history. Skin aging is a phenomenon with direct consequences on our daily lives and on our psychological and social well-being.
A DOUBLE AGING PROCESS…
Due to its constant exposure to external deterioration factors, unlike other organs, skin has the disadvantage of being subjected to both intrinsic aging (that is chronological, linked to the simple passing of time) and extrinsic aging linked to harmful environmental factors, such as ultraviolet irradiation, pollution, and temperature and humidity changes, or to behavioral factors, such as smoking, stress, nutritional errors, etc. Skin aging is manifested in different ways: dehydration, loss of elasticity and texture, atrophy, sagging, fragility, pallor, yellowing, and the appearance of dark spots and wrinkles.
Several molecular and cellular mechanisms that are involved in both intrinsic aging and extrinsic aging work together to alter our skin’s appearance: failure to renew keratinocytes (cells of the skin’s surface layer), decreased synthesis of collagen and elastin molecules (macromolecules involved in the skin’s texture, produced by specialized cells known as fibroblasts), degradation of collagen and elastin molecules by metalloproteases (degradation enzymes activated by UV rays), alteration of skin components by oxygen free radicals and glycation products (two types of toxic molecules, inexorable products of our metabolism), loss of water (dehydration), lipid production deficit (dryness), reduced dermal papilla vascularization (pallor, yellowing), melanin synthesis disorders (hyper- or hypopigmentation), etc.
AN EXHAUSTIVE THERAPEUTIC APPROACH…
The skin is the ideal organ to study the development of deteriorations linked to intrinsic and extrinsic aging, as well as their alteration under the effect of topical and parenteral therapeutic interventions, because it can be directly accessed for observation. With sun exposure having been recognized as a major environmental factor that is likely to accelerate skin aging, researchers in the cosmetics industry initially focused their efforts on the development of effective sunscreens and their integration into cosmetic formulations. With the progress that has been made in understanding the fundamental mechanisms of skin aging, more sophisticated anti-aging strategies have now been developed. To effectively combat age- and sun-related skin deterioration, a comprehensive therapeutic approach is essential. A treatment for mature skin must take into account all the mechanisms involved in skin aging, such as the regeneration of epidermal cells, the synthesis and degradation of extracellular matrix molecules, the hydro-lipid balance, oxidation, glycation, pigmentation, etc. The therapeutic activity of numerous compounds (retinoids, antioxidants, glycation inhibitors, growth drivers, peptides, lipids, anti-inflammatories, polyhydroxy acids, melanogenesis inhibitors, vitamins, minerals) has been scientifically proven on certain aspects of skin aging. These active ingredients, with often synergistic properties, are now incorporated into cosmeceutical formulations.
COSMETICS AND COSMECEUTICALS
Unlike cosmetics, which are products aimed at immediately but only temporarily improving the appearance of the skin through their esthetic properties, cosmeceuticals contain ingredients with scientifically proven biological properties that have a prolonged activity going well beyond their period of application. A wide range of cosmeceutical formulations with varying degrees of clinical efficiency, aimed at removing wrinkles and restoring the skin’s main youthful characteristics, is now available. Cosmeceutical innovations are evolving alongside the clarification of complex links uniting the physiology of the skin and the biological mechanisms of aging. At the same time, the development of new measurement procedures, allowing for an accurate assessment of the potential beneficial effects of anti-aging formulations, must guarantee consumers that these cosmeceutical formulations will fully meet their expectations in terms of prolongation or restoration of their skin’s youth.
