Skin Elasticity and Collagen

• Elastic and reticular fibres give the skin flexibility and strength.
• Rupture of elastic fibres results in permanent striae (stretchmarks), found in pregnancy and obesity, when the skin is over-stretched.
• Collagen fibres bind water and give skin strength, but this ability declines with age, leading to wrinkles.

Collagen

• Collagen consists of tubular structures, each representing a chain of amino acids.
• Three such chains are twisted in a spiral to form a collagen unit.
• Many collagen units join end to end, forming long continuous threads.
• These long threads are stacked side by side.
• During youth, the threads are sparsely cross-linked, allowing them to move past each other, making the connective tissue elastic.
• As age increases, more cross-links form, greatly restricting sliding ability, which results in less elastic tissue.

Amino Acids in Collagen

• Alanine, lysine, glycine, proline, and hydroxyproline are the amino acids found in collagen.
• Vitamin C is essential for the production of hydroxyproline.
• UVA inhibits the formation of collagen, causing deterioration.
• Collagen production starts with pro-collagen, which transforms into collagen.
• Pro-collagen is hygroscopic, binding many times its weight in water.
• With increasing age, pro-collagen content decreases, causing increased dryness and lack of elasticity.

Elastin

• Exactly how elastin is produced is not yet known.
• Soluble pro-elastin undergoes chemical transformations to produce fibrous elastin.
• Glycoproteins exist in the space between collagen and elastin fibers.
• They provide support, lubrication, and the correct environment for the development of fibroblasts.