The idea of growing old just doesn’t creep into the minds of many baby boomers, who are under pressure to look good all the time. New anti-aging actives formulated in creams and serums make consumers feel increasingly more youthful than their actual age as their outer appearances reflect their inner youthfulness. The ever-increasing growth in new products designed to prevent the skin from aging has attracted consumers in droves to the vibrant anti-aging market.

This column will detail the benefits of hyaluronic acid, which is found naturally in our own skin cells. I’ll answer two key questions, namely: how do we keep our skin youthful looking and how can we undo the damage of time?

Hyaluronic acid’s name is derived from the Greek word for glass (hyalos) which accurately describes its transparent glassy appearance. Hyaluronic acid (HA), is the most abundant glycosaminoglycan (GAG) found in human dermis. It was originally discovered in 1934 by Karl Meyer and John Palmer who isolated it from bovine vitreous humor.¹

In young skin, HA is found at the periphery and at interfaces of collagen and elastin fibers. It is thought to help hold together collagen and elastin in the proper configuration. Studies have shown that these connections with HA are absent in aged skin, which may help explain the disorganization of collagen and elastin fibers.²

HA is produced in the human body and is found in the tissue of all animals. It is made by bacterial enzyme-based, bio-fermentation process. Commercial sources include rooster combs and chicken cartilage. It is a negatively-charged, sugar-like molecule of alternating molecules of N-acetyl glucosamine and glucoronic acid. This disaccharide molecule is linked together and belongs to the GAG family of collagen molecule. HA or sodium HA is unique because, unlike other types of collagen, it is not linked to other proteins or sulfur.

HA structure is identical irrespective of its source of origin, which could range from bacterial culture, animals or humans. It is a viscous carbohydrate fluid present in connective tissue as synovial fluid, which is responsible for lubricating and cushioning joints.

Dermatologicals

HA is non-toxic and non-sensitizing, and therefore can be safely used for all skin types and carries no risk of allergic reactions. Dermal fillers enable dermatologists to inject these naturally-occurring components back into the dermis to restore skin’s volume and minimize the appearance of wrinkles. They mimic the natural materials found in our cells and are injected into skin folds, and deep wrinkles to lift and reshape the face. They are the most popular cosmetic procedures because they produce natural looking results. They are reasonable in cost ($450-600 per syringe), efficient and are instantly transforming.

In fact, injections are the fastest growing non-surgical aesthetic procedures.

Patients see the results immediately after just one injection treatment. The effects are temporary but they can last up to six months. Side effects are rare, but they include redness, swelling and bruising. Fillers help skin regenerate natural collagen. It is important to maintain a strong moisture barrier in the top layer of the skin.

Hyaluronic acid has strong water-binding properties, which makes it a key ingredient in wrinkle-fighting treatments.

More Details

There are many different types of fillers and each one has different benefits, usage parameters and duration of effectiveness. In order to develop a gel-like viscosity that could possess an increased residence time, HA is cross-linked. Untreated HA is rapidly broken down by hyaluronidase enzyme. Its half-life is no longer than one day. The most popular cross-linking agent is 1,4-butanediol diglycidyl ether. This process results in HA gels of different viscosity grades.


Commercial dermatological preparations are:

Fillers: These are typically HA derived from rooster combs. Another available grade is Hylaform Plus, called Captique. It is similar to Hylaform except it is derived from bacteria. This product has been withdrawn from US market. Restylane is a hyaluronic acid product that is also derived from bacteria. Juvederm, both ultra and ultra plus grades, are non-animal derived dermal fillers consisting of a smooth gel. The ultra plus grade is stronger, giving dermatologists the ability to better treat deeper folds and wrinkles. It also lasts a little longer.

Topicals: HA is important for tissue repair and maintaining skin hydration.³ HA binds water up to 500 times its weight. Hyaluronic acid does not penetrate the skin because of its large molecular size.⁴ HA, and its derivative sodium HA, are used in cosmetic formulations for their strong water-binding capabilities. It brings moisture up to the top layer of the skin and keeps skin hydrated. When it is formulated in creams and serums, it provides skin moisturization lasting for few days.
HA has the ability to pull moisture from the atmosphere and trap it on the surface of the skin only, because it can’t penetrate the stratum corneum and enter the epidermis.⁵ It has been shown that soy isoflavones can increase levels of GAG and specifically HA in aging skin, although the exact mechanism is not known.⁶

Hyaluronic acid is responsible for maintaining skin water balance, providing hydration, lubrication and cellular function as well as imparting a cushion effect between the joints. It provides a reservoir of water within the skin. In aging skin marked by dehydration, sagging, and wrinkles, a remarkable improvement is demonstrated when skin’s HA levels are boosted.

Conclusions

The loss of hyaluronic acid in the human body is one of the causes of wrinkles. Hyaluronic acid-injected fillers make skin look younger and improve its tone, making it smooth and supple. Effective active ingredients such as retinoids, peptides and HA are gaining credibility in high-end anti-aging preparations. Regular use of skin care products containing such actives can undo the damage of time.
However, the effectiveness of hyaluronic acid oral supplementation remains somewhat controversial.

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References:

1. J. Biol. Chem. 107:629-34, 1934
2. Int. J. Derm.33(2):119-22, 1944
3. Sudel KM etal - Photochem. Photobiol. 2005; 81:581-587
4. Zettersten EM, etal. J. Am. Derm. 1997; 37:403
5. Cosmetics & Toiletries, 113 (3) 35-42., 1998
6. Photobiol. 2005; 81:581-587

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Navin M. Geria
Senior Technical Advisor and Principal
Doctors Skin Prescription
E-mail: tokuho02@optonline.net

Navin Geria, ex-Pfizer Research Fellow, is senior technical advisor and principal of the dermatological research company, Doctors Skin Prescription (DSP), Boston, founded by dermatologist David J. Goldberg M.D.J.D. and plastic surgeon William P. Adams M.D.F.A.C.S. Geria has more than 30 years of experience in the personal care industry and was previously with Clairol, Warner-Lambert, Schick, Bristol-Myers and most recently SpaDermaceuticals. He has earned nearly 20 US patents, has been published extensively and has been both a speaker and a moderator at cosmetic industry events.