Botulinum toxin in dermatology - beyond wrinkles and sweat

Botulinum neurotoxin serotype A inhibited ocular angiogenesis through modulating glial activation via SOCS3

BACKGROUND

Pathological angiogenesis causes significant vision loss in neovascular age-related macular degeneration and other retinopathies with neovascularization (NV). Neuronal/glial-vascular interactions influence the release of angiogenic and neurotrophic factors. We hypothesized that botulinum neurotoxin serotype A (BoNT/A) modulates pathological endothelial cell proliferation through glial cell activation and growth factor release.

METHODS

A laser-induced choroidal NV (CNV) was employed to investigate the anti-angiogenic effects of BoNT/A. Fundus fluorescence angiography, immunohistochemistry, and real-time PCR were used to assess BoNT/A efficacy in inhibiting CNV and the molecular mechanisms underlying this inhibition. Neuronal and glial suppressor of cytokine signaling 3 (SOCS3) deficient mice were used to investigate the molecular mechanisms of BoNT/A in inhibiting CNV via SOCS3.

FINDINGS

In laser-induced CNV mice with intravitreal BoNT/A treatment, CNV lesions decreased > 30%; vascular leakage and retinal glial activation were suppressed; and Socs3 mRNA expression was induced while vascular endothelial growth factor A (Vegfa) mRNA expression was suppressed. The protective effects of BoNT/A on CNV development were diminished in mice lacking neuronal/glial SOCS3.

CONCLUSION

BoNT/A suppressed laser-induced CNV and glial cell activation, in part through SOCS3 induction in neuronal/glial cells. BoNT/A treatment led to a decrease of pro-angiogenic factors, including VEGFA, highlighting the potential of BoNT/A as a therapeutic intervention for pathological angiogenesis in retinopathies.

Evaluation of Efficacy of Corticosteroid and Corticosteroid Combined with Botulinum Toxin Type A in the Treatment of Keloid and Hypertrophic Scars: A Meta-Analysis

BACKGROUND

Both keloid and hypertrophic scars are common benign skin lesions manifested by hyperplasia of fibroblasts. Clinically, this will not only have physiological effects on patients, but also cause psychological damage. However, there is no unified standard treatment method at present. Intralesional corticosteroid injection alone and corticosteroid combined with botulinum toxin type A has been gradually found to be useful for the treatment of keloid and hypertrophic scars, but the difference in efficacy between the two is controversial.

METHODS

A systematic search was made of the relevant experiments from Web of Science, PubMed, Scopus, Google Scholar, Cochrane Library, and China National Knowledge Infrastructure (CNKI).

RESULTS

The scores of Visual Analog Scale (VAS), Vancouver Scar Score sheet (VSS), scar thickness, itching degree and patient satisfaction after the combination of corticosteroid and botulinum toxin type A were superior than those after corticosteroid (P<0.05).

CONCLUSION

Compared with corticosteroid alone, corticosteroid combined with botulinum toxin type A is more effective in the treatment of keloid and hypertrophic scar. Although clinical case studies for the treatment of keloid or hypertrophic scars are limited, it is necessary and helpful to understand the effectiveness of corticosteroid combined with botulinum toxin type A in the treatment of keloid or hypertrophic scars.

LEVEL OF EVIDENCE III

This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Botulinum toxin (Botox) A for reducing the appearance of facial wrinkles: a literature review of clinical use and pharmacological aspect

Background: Botulinum toxin (Botox) consists of 7 types of neurotoxins; however, only toxins A and B are used clinically. Botox A is used for several disorders in the field of medicine, particularly in dermatology, for cosmetic purposes. It is produced by the bacterium Clostridium botulinum and can be used as a treatment to reduce the appearance of wrinkles in the upper areas of the face, elevate the eyebrows and treat problems such as hyperhidrosis, lichen simplex, pompholyx (dyshidrotic eczema) and acne vulgaris.

Objectives: This article provides a literature review regarding the general issue of Botox as a treatment for reducing facial wrinkle.

Discussion: Botox works by blocking the release of acetylcholine, resulting in paralysis of the local muscles, which usually occurs 24 hrs to two weeks following Botox injection. This effect will last three to six months. The optimal dose of cosmetic Botox in dermatology is 20 units. Botox is relatively safe and does not result in any adverse side effects. However, in certain circumstances, the effect of Botox will gradually resolve, resulting in reduced muscle paralysis over time.

Conclusion: Botox is good and safe medicine to reduce the appearance of facial wrinkles.

Intralesional triamcinolone alone or in combination with botulinium toxin A is ineffective for the treatment of formed keloid scar: A double blind controlled pilot study

Cutaneous injury can ignite excessive fibroproliferative growth that results in keloid formation. Keloids are associated with significant morbidity related to disfigurement and/or symptoms (e.g., pain and pruritus). First-line treatment of formed keloids involves topical or intralesional steroids. Recurrent or resistant keloids are managed by surgical excision or cryotherapy, followed by steroidal application or adjuvant irradiation. Although adjuvant irradiation appears to be most efficacious, alternative therapeutic options are needed for patients without access to radiation centers. Botulinum Toxin A (BTA) appears to have similar inhibitory effects to irradiation on the cell cycle via downregulation of pathogenic cytokines. Herein, we conducted a study to compare the efficacy of intralesional triamcinolone used alone, or in combination with BTA, in the treatment of formed keloid scars. Twenty patients with a cumulative of 40 keloids completed the study. There was no significant difference between treatment arms with respect to height vascularization, pliability, and pigmentation scores. The addition of BTA resulted in significant symptomatic improvement of pain and pruritus as compared to intralesional triamcinolone alone (p < 0.001). Irradiation is only effective when administered in the adjuvant setting where inhibitory effects on cell cycle and migration are optimized. Future studies with intralesional triamcinolone and BTA should be performed adjuvantly.

Use of botulinum A toxin for proctalgia fugax-a case report of successful treatment

Proctalgia fugax is considered as intermittent anal pain of unknown etiology; a variety of treatments have been used, without, however, permanent results. Injection of botulinum A toxin is recently suggested as an alternative option. We present the case of a woman presenting proctalgia fugax that was untreatable through other current forms of treatment. After two administrations of botulinum A toxin, 80 units and 100 units each, the patient remained asymptomatic on 8-month follow-up control. Botulinum A toxin injection can reduce internal anal sphincter pressure, leading to relief of symptoms, and seems a promising option with minimal morbidity in cases on proctalgia fugax that does not respond to other current treatments.

Bioimaging of botulinum toxin and hyaluronate hydrogels using zwitterionic near-infrared fluorophores

Background

The injection of botulinum toxin (BTX) to reduce facial wrinkles is one of the most frequently performed plastic surgery procedures. The biocompatible hydrogels are injected with BTX for effective tissue augmentation. However, it is difficult to determine the interval of injection for effective tissue augmentation.

Method

BTX and hyaluronate (HA) hydrogels were labeled with zwitterionic (ZW) near-infrared (NIR) fluorophores and visualized for 3 weeks after injection to BALB/c nude mice.

Results

BTX-ZW conjugates and diaminohexane (DAH)-HA-ZW hydrogels were successfully prepared by the conventional EDC/NHS chemistry. Using the NIR fluorescence imaging, we confirmed that approximately 10% of BTX-ZW conjugates and 50% of DAH-HA-ZW hydrogels remained 3 weeks post-injection.

Conclusion

This bioimaging technique using invisible NIR fluorescence light can be exploited for various biomedical applications.

Management of familial benign chronic pemphigus

Benign familial chronic pemphigus or Hailey-Hailey disease is caused by an autosomal dominant mutation in the ATP2C1 gene leading to suprabasilar acantholysis. The disease most commonly affects intertriginous areas symmetrically. The chronic nature of the disease and multiple recurrences make the disease bothersome for patients and a treatment challenge for physicians. Treatments include topical and/or systemic agents and surgery including laser. This review summarizes the available treatment options.

Aquagenic keratoderma. Two new case reports and a new hypothesis

Aquagenic keratoderma has been described as a transient condition affecting predominantly young females and defined clinically by the appearance of palmar hyper-wrinkling accentuated after immersion in water. We present two new cases with aquagenic palmoplantar acrokeratoderma - a child and a young male. A significant clinical improvement was achieved after topical treatment with aluminum salts. Aquagenic palmar keratoderma may be a clue to cystic fibrosis in adolescents and young adults. We developed a new hypothesis on its pathogenesis.

Pharmacological sphincterotomy for chronic anal fissures by botulinum toxin a

Chronic anal fissure is a common proctologic disease. Botulinum toxin (BTX) can be used for temporary chemical denervation to treat this painful disorder. Its application is by intramuscular injections into either the external or internal anal sphincter muscle. The mode of action, application techniques, and possible complications or adverse effects of BTX therapy are discussed in this report. The healing rate is dependent on the BTX dosage. The short-term healing rate (</= 6 months) is 60-90%, whereas about 50% of the patients show a complete response in long-term follow-up studies (> 1 year). Adverse effects are generally mild, but relapses occur more often than with surgery. Conservative therapy is currently considered as a first-line treatment. With increasing evidence for its efficacy, BTX can now be considered among the first-line nonsurgical treatements. Although, surgical management by lateral sphincterotomy is the most effective treatment, it shows a higher incidence of incontinence and greater general morbidity rate than BTX. BTX is a useful alternative to surgery and in many cases, surgery can be avoided with the use of BTX.

Proctalgia fugax, an evidence-based management pathway

PURPOSE

Proctalgia fugax (PF) is a benign anorectal condition which has been described in the literature since the nineteenth century commonly presenting to general surgeons. There is little high level evidence on the subject and its therapeutic modalities. We aimed through this systematic literature review to outline the definition and diagnostic criteria of this condition, the aetiology and differential diagnoses and describe the different treatment modalities that have been attempted and their success.

METHOD

A literature search of Google Scholar and Medline using Pubmed as the search engine was used to identify all studies directly related to the definition, aetiology and treatment options for this condition (latest at 12 August 2008) was performed.

RESULTS

The search produced 61 references with three others obtained from the references of these papers. The prevalence of PF in the general population ranges from 4% to 18%. The diagnosis is based on the presence of characteristic symptoms as defined by Rome III guidelines and physical examination. The mainstay of treatment is reassurance and careful counselling with evidence in the literature for warm baths, topical treatment with glyceryl trinitrate or diltiazem and salbutamol inhalation. In persistent cases, local anaesthetic blocks, clonidine or Botox injections can be considered after clarification of risk and benefit.

CONCLUSION

Based on this we suggest that diagnosis should be made through exclusion of common organic causes such as haemorrhoids, anal fissure or anorectal carcinoma and on the fulfillment of Rome III criteria. The main treatment for this benign condition remains reassurance and topical treatment.

Botulinum toxin type A reduces histamine-induced itch and vasomotor responses in human skin

BACKGROUND

Clinical evidence has revealed the antipruritic effect of botulinum toxin type A (BoNT/A). BoNT/A is believed to be effective against itch as it inhibits the release of acetylcholine as well as some other substances that may be involved in itch.

OBJECTIVES

To investigate the effect of subcutaneous administration of BoNT/A on experimentally histamine-induced itch in human skin.

METHODS

In this double-blind, placebo-controlled study, 14 healthy men (mean +/- SD age 26.3 +/- 2.6 years) received BoNT/A (Botox; Allergan, Irvine, CA, U.S.A.; 5 U) and isotonic saline on the volar surface of either forearm. Histamine prick tests were performed four times at the treatment sites (before treatment, and days 1, 3 and 7 after treatment). The itch intensity (as rated on a 0-10 visual analogue scale), itch area, neurogenic inflammation (visible flare area), blood flow (laser Doppler) and cutaneous temperature (thermographic images) were measured over the course of the trials.

RESULTS

BoNT/A reduced the histamine-induced itch intensity (F(1,39) = 30.2, P < 0.001) and itch area (F(1,39) = 8.8, P = 0.011) compared with saline at all time points after treatment. The duration of itch was also shorter for BoNT/A-treated areas (F(1,39) = 19.4, P < 0.001), with a peak effect at day 7. The flare area was smaller in the BoNT/A-treated arm compared with the saline-treated arm at all time points after treatment (F(1,39) = 15.4, P = 0.002). Findings from blood flow (F(1,26) = 177.3, P < 0.001) and temperature measurements (F(1,26) = 27.6, P < 0.001) clearly showed the suppressive effect of BoNT/A on vasomotor reactions, with the maximal effect on days 3 and 7.

CONCLUSIONS

BoNT/A reduced the itch intensity, blood flow and neurogenic inflammation in response to the histamine prick test in human skin. The findings could be applicable in the treatment of some pruritic conditions that can be difficult to treat with conventional treatments.

Botulinum toxin, Quo Vadis?

Botulinum toxin (BTX), derived from the exotoxin of Clostridium botulinum, cleaves Soluble N-ethylmaleimide-sensitive factor-Attachment protein REceptor (SNARE) proteins, causing chemodenervation of cholinergic neurons. BTX also inhibits exocytosis of vesicles containing norepinephrine, glutamate, substance P and calcitonin gene-related peptide (CGRP) and inhibits expression of the vanilloid receptor. Clinical applications of BTX, which include the treatment of overactive skeletal and smooth muscles, hypersecretory and painful disorders, have increased exponentially since it was first used clinically to treat strabismus more than two decades ago. In this editorial, we discuss reports of new therapeutic indications of BTX, and propose new areas for research.