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Neurotoxins: Wrinkle Relief & Prevention

Abstract:

Onabotulinum Toxin A ( BoTNA), is the gold standard treatment for temporary reduction of dynamic rhytid. However there are some evidences which repeated treatments over a long time may have preventative and progressive reductions of rhytides, however more study required to explain the exact mechanism of additional benefits of BoNTA beyond temporary paralysis of muscle.

Introduction:

BoNTA has been introduced over two decades ago and is the most common cosmetic treatment in USA. It blocks the release of acetylcholine and prevents the treated muscle to contract. As a result the dynamic rhytides ( wrinkles induced by facial movements) will be reduced or completely fades away. However,there are evidences, in people who receives repeated treatment over glabellar, pre-orbital and frontal muscles, over time, it can prevent new dynamic rhytids formation and may progressively reduce static (resting) wrinkles as well.

It also improve the quality of skin.

The exact mechanisms are not known, however, it may be due to triggering new collagen formation by stimulating fibroblasts, and or reorganizing the old collagen fibers on treated areas.

Also, the interval of next treatment maybe wider with people who received repeated treatment, over time.

Mechanism of additional benefits of BoNTA with repeated treatment ( theories):

First, theory of learned response, in which patients avoid using as much as used which causes wrinkles.

Second;physiologic muscle response, in which even a single injection causes some atrophy(shrinking) of the treated muscle for a period of up to 12 months. It is obvious wrinkle formation stops after muscle movement inhibited by injection of BoTNA.

However, what is less known, its reducing effect on established wrinkles over repeated treatments progressively and cumulatively.

To be able to explain better, it is worth mentioning that human skin has three important biomechanical characteristic: strength, pliability ( ability to stretch) and elasticity ( ability to recoil). With aging these biomechanical features change and exacerbates with UV exposure.

Recent study ( a Cohort study on 48 women, with a single treatment of BoNTA) shows a significant improvement in elasticity and pliability could be measured up to four months after the treatment. The biomechanical changes in the skin induced by BoNTA are the opposite of caused by aging.

The extracellular matrix ( ECM) of skin, composed mainly, of collagen, in addition to glycosaminoglycans and elastin fibers. Collagen, is the most abundant protein in the skin, and is responsible for the integrity and proper functioning of the skin.

Biopsy of the skin in 18 volunteers with moderate to severe wrinkles, before and 3 months after

Periorbital injection of BoTNA shows the collagen became more compact and organized compare to baseline biopsy, however, histochemical analysis did not show any change in the level of elastin or collagen fibers.So, this may explain the extended improvement and results induced by, repeated injection in extended periods. Other study shows BoNTA may activate fibroblast cell activity which causes skin remodeling.

Individual practitioners, often, influenced by their own daily observation and patients feedbacks which, further proves, that regular and repeated injections of BoNTA, results in better skin quality, less wrinkles and longer lasting results in compare to sporadic treatment. This makes sense, as repeated injection, prevents return of muscle function, consequently, less muscle movement causes less crease and better collagen reorganization which prevents new wrinkle formation and more youthful skin.

Conclusions:

BoNTA, is inseparable part of cosmetic medicine and the most common non invasive cosmetic treatment in the past two decades. It has become evident, that it is no longer merely a temporary muscle paralyzing agent, as, it can induce better skin quality, less wrinkles and its effect last longer if been performed on a regular base for a longer period vs. sporadic use