FOCUS ON HYALURONIC ACID
1. WHAT IS HYALURONIC ACID?
A key molecule for our tissues
Hyaluronic acid is a long molecule which exists naturally in the human body, as well as in
animals and some bacteria.
We produce cells called fibroblasts (as well as other cellular populations e.g. synoviocites)
in order to protect and hydrate the tissues, giving them their firmness and plasticity.
These are found in large concentrations in the dermis, a connective tissue in the skin, but
they are also present in the tendons, in the vitreous humour of the eye, in the synovial
liquid filling the joint cavities, the aortic walls and the umbilical cord.
In time, the quantity of hyaluronic acid present in the organism tends to fall, generating
phenomena such as ageing of the skin, loss of plasticity and compactness of the skin and
the appearance of wrinkles, as well as possible problems with the joints and a general
reduction of tissue elasticity.
2. HOW DOES IT WORK?
A hydrating and protective sponge
Hyaluronic acid has a strong hydrating power because of its chemical-physical properties.
From a chemical point of view it is classified as a glycosaminoglycan (GAG): the molecule
is actually formed by repeated long sequences of two simple sugars, glucuronic acid and
N-acetylglucosamine. This results in a linear, flexible and significantly polar molecule,
which is extremely soluble in water.
It is really because of its molecular structure that hyaluronic acid behaves like a sponge,
capable of absorbing, firmly holding and releasing large quantities of water based on local
requirements.
Together with collagen this is an essential constituent and elastic fibre from what is known
as the “extra cellular matrix” or “ECM” – of the dermis, guarantees the right degree of skin
humidity.
In addition to its capacity to bind water, this valuable macromolecule acts as a lubricant
and is capable of absorbing impacts to the moving parts of the human body and on the
joints. It has an important function in the transportation of nutritional substances. It also
protects the organism from viruses and bacteria: as a result of their length and strong
hydrating ability the molecules of hyaluronic acid organise a structure of a reticular type in
the dermis, as well as giving tone and form to the tissue, constituting a filter against the
diffusion of potentially toxic substances. It also has significant anti-inflammatory and
healing properties, encouraging the production of new collagen and the processes of
tissue repair.
3. A BIT OF HISTORY
From its discovery by Karl Meyer to modern biotechnologies
The history of hyaluronic acid began in 1934, when the biochemist Karl Meyer and his
assistant John W. Palmer isolated the molecule in the bovine vitreous humour for the first
time in the laboratories of Columbia University. The two researchers called the substance
Hyaluronic Acid, from Hyalos, which in Ancient Greek means vitreous, together with Uronic
Acid, one of the saccharide fractions constituting hyaluronic acid.
However the modern era for hyaluronic acid only began when, a long time afterwards, its
presence in the various connective tissues and the dermis in addition to the vitreous
humour and its fundamental role in skin hydration and in the cellular metabolism was
identified. It was first used for human beings in the 1980s. Special viscous gels based on
hyaluronic acid were injected in some ophthalmic operations. Then the substance proved
effective for joint problems and then in dermocosmetics.
Initially the molecule was extracted using very complex procedures involving animal
tissues such as rooster combs. Today biotechnology can be used to obtain hyaluronic acid
by fermentation of bacterial cultures.
4. HOW AND WHEN IS IT USED?
A valuable friend not simply for the skin
Nowadays, when we talk about hyaluronic acid, it is immediately associated with the most
advanced anti-wrinkle treatments and new frontiers of dermocosmetics.
Undoubtedly the anti-ageing properties of this molecule have led to a small but important
revolution in the cosmetics field. In fact, hyaluronic acid fillers allow all kinds of beauty
problems to be tackled, from remodelling cheekbones, restoring the firmness and
hydration of the face, hands and décolleté area, and even increasing lip volume. The big
advantage of a biocompatible substance, already produced by our body, is the fact that it
has virtually no contraindications in subjects in good health.
But maybe not everybody knows that hyaluronic acid has numerous, effective applications
in many other medical and therapeutic fields:
In ophthalmic surgery, because of the production of artificial tears in the treatment of dry
eye syndrome and as a viscoelastic solution in cataract surgery. It is used in ear surgery
as a regenerator of perforated tympanic membrane: the application of hyaluronic acid
stimulates the formation of healing tissue. In inflammatory situations and mouth ulcers,
aphthae and stomatitis, or in second and third degree burns, there are treatments which
benefit from the reparatory properties of this molecule.
In rheumatology and orthopaedics hyaluronic acid is used as an intraarticular therapy, not
simply as a lubricant of synovial fluid, but also with a protective role for the tissues, limiting
the penetration of free radicals and proteolytic enzymes. In the urological field, finally,
hyaluronic acid in synergy with other substances carries out an important antiinflammatory and reparative function for the epithelium of the bladder (urothelium). In the
case of wounds, ulcers and burns, this molecule has proved particularly effective at
speeding up and favouring the healing and reparatory process in tissues.