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Extracellular Matrix (2)

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Cosmetic products advertising the importance of collagen have become ubiquitous, and many are now aware of its significance in skincare. However, collagen is not the only essential component of the skin. Understanding the skin’s composition is essential to maximize the efficacy of different products.

The skin comprises three layers – the epidermis, dermis, and subcutaneous layer. Collagen, which is frequently mentioned, is mainly found in the dermis. The loss of collagen leads to skin aging, resulting in fine lines, enlarged pores, and reduced elasticity. The dermis contains different types of cells, including fibroblasts, hair follicle cells, blood vessel cells, sweat gland cells, and more. The extracellular matrix (ECM) is the space between cells and is akin to a building’s framework, providing a place for cells to reside.

The ECM is crucial in the skin, and while glycosaminoglycans (GAGs) play a vital role, the other two types, proteoglycans and structural proteins, are equally important. Proteoglycans are composite sugars consisting of protein and GAGs. They can form a gel-like substance that includes several other matrix components. A core protein molecule can connect to over 100 GAG chains. Proteoglycans are vital in cell movement, proliferation, differentiation, signal transduction, cell adhesion, and cell-matrix interaction. Studies have linked decreased proteoglycan content to skin aging, and it may be a crucial anti-aging element in the future.

Structural proteins, such as collagen and elastin, are vital components of the skin structure. In the ECM, these proteins are akin to cement and steel, giving it strength and resilience. Collagen is the most abundant protein in the human body, comprising over 30% of total protein content. At least 19 collagen types with different chemical and immunological properties exist, and types I and III collagen are present in the skin. Stimulating type I collagen synthesis is a common principle in medical aesthetics today. Elastin provides skin tissue elasticity, making it stretchy. Its elasticity is at least five times greater than that of a rubber band of the same cross-sectional area. Reduced elastin content causes skin to lose elasticity and age.

In addition to the aforementioned substances, the ECM contains other components, such as fibronectin and laminin. Understanding the ECM is crucial to comprehend the real impact of skin aging beyond collagen loss. These components bestow specific functions on the skin, and a change in any of them may lead to skin aging.