Collagen and elastin: the proteins synonymous with suppleness and firmness.

Elastin is a proteinsecreted by fibroblasts, the primary cells of connective tissue. As a reminder, connective tissue is a supportive tissue; the dermis, the deep layer of the skin, is a connective tissue unlike the epidermis, the more superficial layer, which is an epithelial tissue.

Elastin is a major protein component of tissues found in the skin, but also in the lungs, arteries, bladder, elastic ligaments and cartilage. Elastin is synthesised from a soluble precursor known as tropoelastin through the cross-linking of lysine residues by lysyl oxidases. Following this, elastin is composed of soluble tropoelastin, residues of glycine, valine, proline and modified alanine.

The role of elastin is to enable various elements of the body to maintain their shape even after being stretched. It thus allows the skin to return to its original state very quickly after being stretched, pricked or pinched. Thanks to elastin, the skin is perfectly stretchable with improved tonicity.

With an equal diameter, elastin is five times more elastic than arubber band !

Nevertheless, the production of elastin by fibroblasts ceases at puberty. Even though elastin proteins are resilient and hard to degrade, certain enzymes known as elastases, also secreted by fibroblasts, are capable of cleaving them and making them less effective. Consequently, the skin loses its elasticity and wrinkles become more pronounced.

Elastin, as such, exists as a cosmetic active ingredient; it is derived from the marine environment, thus we refer to it asmarine elastin even though the INCI name remains ELASTIN. However, products containing it are very rare on the market. We rather find treatments containing elastin boosting actives such as "Calcium 2-ketogluconate". Elastin is more common in dietary supplements even though the effectiveness on the skin after ingestion of such a compound is a subject of debate in the scientific community.

Naturally present in the body, collagen is the most abundant protein in the human body: it accounts for about 25% of the proteins recorded in the body. Produced by fibroblasts, it provides a mechanical resistance to stretching and a structure to many of the body's connective tissues, which is why collagen is found, among other things, in the skin, muscles, bones, ligaments, tendons, hair...

There exist 28 types of collagen with different properties depending on where it is located, of which type I is the major component of the extracellular matrix of the dermis, representing 80 to 90% of the total collagen. It is characterised by three polypeptide chains organised in a helical manner and each composed of a thousand amino acids linked together by disulphide bridges to form patterns (called sequences). Glycine is the most represented amino acid, but it is also rich in proline and hydroxyproline.

Collagen holds significant importance for the skin. Present in the form of fibres, it ensures tissue regeneration, provides a high degree of elasticity, imparts flexibility and resistance, and acts as a binder between skin cells, helping to maintain its structure. The issue is that as the years pass, collagen synthesis slows down. This loss can begin around the age of 25, and the body can lose approximately 1% of collagen per year, and progressively up to 25% per year. Thus, by the age of 80, we have lost 75% of collagen compared to young adults. Moreover, over the years, collagen fibres become rigid, fragmented and disorganised.

These phenomena promote the appearance of wrinkles, loss of firmness and elasticity in tissues, and sagging of the skin. On the other hand, a lack of collagen in the skin results in an irregular skin texture: the skin loses its radiance and the complexion becomes less uniform. Unprotected exposure to UV rays, smoking, air pollution, not to mention the role of diet with glycation (the binding of sugars to collagen) leading to a stiffening of this protein, all contribute to this premature degradation of collagen.

To slow down skin ageing, the external supply of collagen can be beneficial. Therefore, it can be used in cosmetics to compensate for the decrease in production associated with age, thereby helping to reduce the depth of wrinkles and improve the appearance of the skin.

Caution! Generally, the collagen used in cosmetology is of animal origin: it is either extracted from beef or pork cartilage, or from the skin, bones and scales of fish. The INCI name gives no indication of the source of the collagen. Therefore, it is necessary to approach the manufacturer to know its origin. The one used in our wrinkle and firmness loss serum is of plant origin: it consists of plant fragments of type I collagen that mimic human collagen and has been transiently generated through wild plants. The Nicotiana benthamiana is the one used to serve as a support. To do this, a synthetic fragment of human type I collagen was cloned and transcribed in vitro, before being inserted into the cytoplasm of the plant cells.