Hyaluronic acid


In chemical terms: glycosaminoglycans, ie. GAG consisting of polymer of disaccharide units 

A molecule with huge mass, about 5-6 million daltons (comparing to water molecule, which has a mass of 18 daltons); consisting of disaccharide units bonding with even more ten thousands repetitive glycosidic bond, and acidic due to the glyruronic acid's carboxil group.

Hyaluronic acid belongs to GAG compounds  along with hyaluronan, heparin, heparan sulfate, chondroitin sulfate, keratan sulfate and dermatan sulfate. Almost all of our somatic cells can produce it, and it can be found in many parts of our body (skin, cartilage, joints, blood, eyes, ovum, mother's milk, etc.)
Its distribution in the body:
  • 55- 60% in the skin;
  • about 30- 35 % in muscles and bones;
  • 9 % in other parts, like synovial fluid, umbilical cord, blood, lymph.
In the tissues it is able to link the extracellular matrix into a network and fill it, also it is able to imbibe water 1000 times its weight, ensuring the tissue's filled space and flexibility - turgor.
Hyaluronic acid can contribute to the functioning of immune system, since it is an excellent antioxidant and has antibacterial effects  as well.
Interesting fact:  The hyaluronic acid in mother's milk contributes to the development in the baby's intestinal flora. The hyaluronic acid content of our body continuously reduces, its amount is the highest in newborn babies' connective tissues, and its production starts to slow in the twenties. 

Hyaluronic acid's role in the skin:

The first we think of: hydration, ensuring elasticity (turgor).
It also has many other important functions.
More than half of the body's hyaluronic acid supply can be found in the deeper layer of skin, in the dermis.
Along with ingredients of fibrous proteins (collagen, elastin) it is created by the fibroblasts, and with their linkage proteoglycans are produced, which are the building components of extracellular matrix. 

ECM= extracellular matrix.
Within the proteoglycan molecules  many glycosaminoglycans link to the extracellular proteins with covalent bond. Due to the negative functional groups of glycosaminoglycans the proteoglycans will also be negative, therefore it can bind a significant amount of cations and water molecules. These provide the structure and medium that ensures the water's binding and storing of appropriate amount, providing the proper tissue turgor.
It does not mean the skin's water storage only: the connective tissue matrix is responsible for the 75-80 % of the body's mobilizable water amount. It provides proper medium for the connective tissue cells' poliferation,metabolism, and migration - that is, for their perfect living conditions - therefore they are suitable for the restoration of skin's biological age. 

Interesting fact:  by linking to cell membrane's lipids and proteins the hyaluronic acid participates in the cell wall's production out of the cell membrane, by creating glycolipids and glycoproteins, which provide mechanical and anti-dehydrational protection, and play an important role in cell's immune reactions, binding pathogens, production of receptor molecules, cell's communication and adhesive ability. 

  • By forming proper volument and structure it contributes to skin's blood circulation and the support of capillary vessels.
  • Due to its great viscosity it prevents the advance of pathogens and alien materials in the connective tissue, obstructs the spread of infections, and it is also an important part of the skin's internal defence, the esophylaxia.
The most crucial evidence for  hyaluronic acid significance is the fact that the fetal injuries heal without marks due to the extremely high hyaluronic acid content of fetal tissues.  
The  water-binding capability of the skin reduces rapidly after 30, so the "thirsty" connective tissue's vitamin and nutriment provision decreases, therefore the free radical formation increases. By the age of 70-75 the skin's hyaluronic acid content decreases to its quarter. The aging process starts spectacularly, wrinkles start to appear on the skin, its elasticity decreases. 

The skin's hyaluronic acid content while aging.
The reasons for the decreasing hyaluronic acid are the diminishing activites of fibroblasts on the one hand, and the growing of dissimilation processes during aging on the other hand. 
The activity of hyaluronidase ensimes increases in the skin, which are in charge of deomposition of proteoglycans. Gags (they are enhanced by inflammation processes, increased oxidation stress, free radicals).

Researches proved that by treating the skin with hyaluronic acid not only the lack formed in the meantime can be substituted, but the functioning of metaloprotease enzymes can also be restricted, and with time, the natural, own hyaluronic acid, the endogen's production can be enhanced within the tissue. 
In infinitely simplified terms the aging process  is oxidation and losing water. On the grounds of the above mentioned facts it is obvious why hyaluronic acid is one of the most effective and popular weapon against the skin's aging.
Lavender Centrum /Medical&Beauty&Manicure/ Medical Cosmetology