Wrinkles can sometimes be considered as “charming” but only a few find them attractive per se. The most obvious proof of this universal fight against wrinkles is the consistent increase in revenue performed by anti-agers over the last five years, despite of the recession.
Although growth slipped slightly to 7% in 2009 (from 9% in 2008), it still far outperformed the overall global skin care category (3% growth) as well as the global beauty and personal care industry as a whole (4% growth1). Wrinkles appear gradually; they are the result of the multiple, daily stresses that our face undergoes. Each frown, and unfortunately, each smile and laugh, contributes to gradually deepening these lines in the skin. Slow but cumulative destruction of the macromolecules of the dermis and the dermal-epidermal junction progressively diminish the youthful qualities of the skin. During the ageing process, the synthesis of filling macromolecules diminishes, and destruction is no longer offset as it should be. Synthesis is no longer integrated, and molecular associations become unbalanced. The dermal-epidermal junction, which is highly complex and rich in macromolecules, becomes less dense and therefore less able to adapt to stress.
Role of collagens I, III and IV
Collagen is one of the most abundant proteins of the extra-cellular matrix.2 Collagen I, along with collagen III, constitutes 80% of the collagen in the dermis, while type IV collagen is the major component of the basement membrane. Collagen molecules are helicoidal trimeric proteins secreted by the fibroblasts. The collagen I and III molecules auto assemble to each other in the dermis in order to form the characteristic fibres of the tissue. In that way they constitute the cross-linked structure able to resist the various physical stresses (extensions) the skin undergoes. Collagen III has the particularity to be produced by the young fibroblasts and during the early phases of wound healing. It is the collagen of “youth”, its proportion decreases with age to the advantage of collagen I. It is less resistant than collagen I, but could be partly responsible for the skin’s smoothness. The collagen type IV is part, with laminin-5, of the anchorage proteins of the basement membrane, at the interface of the extracellular matrix (dermis) and the basal layer cells (epidermal proliferative keratinocytes). It plays an important role in ensuring the cohesive function of the dermal-epidermal junction.
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