Elastin structure and its involvement in skin photoageing

Skin aging is a complex process that may be caused by factors that are intrinsic and extrinsic to the body. Ultraviolet (UV) radiation represents one of the main sources of skin damage over the years and characterizes a process known as photoaging. Among the changes that affect cutaneous tissue with age, the loss of elastic properties caused by changes in elastin production, increased degradation and/or processing produces a substantial impact on tissue esthetics and health. The occurrence of solar elastosis is one of the main markers of cutaneous photoaging and is characterized by disorganized and non‐functional deposition of elastic fibers. The occurrence of UV radiation‐induced alternative splicing of the elastin gene, which leads to inadequate synthesis of the proteins required for the correct assembly of elastic fibers, is a potential explanation for this phenomenon. Innovative studies have been fundamental for the elucidation of rarely explored photoaging mechanisms and have enabled the identification of effective therapeutic alternatives such as cosmetic products. This review addresses cutaneous photoaging and the changes that affect elastin in this process.     

Oxidization of squalene,a human skin lipid: a new and reliable marker of environmental pollution studies

A review of the oxidization of squalene, a specific human compound produced by the sebaceous gland, is proposed. Such chemical transformation induces important consequences at various levels. Squalene by‐products, mostly under peroxidized forms, lead to comedogenesis, contribute to the development of inflammatory acne and possibly modify the skin relief (wrinkling). Experimental conditions of oxidation and/or photo‐oxidation mechanisms are exposed, suggesting that they could possibly be bio‐markers of atmospheric pollution upon skin. Ozone, long UVA rays, cigarette smoke… are shown powerful oxidizing agents of squalene. Some in vitro, ex vivo and in vivo testings are proposed as examples, aiming at studying ingredients or products capable of boosting or counteracting such chemical changes that, globally, bring adverse effects to various cutaneous compartments.