The non-neuronal and nonmuscular effects of botulinum toxin: an opportunity for a deadly molecule to treat disease in the skin and beyond

Investigating the impact of botulinum toxin type a on the migration of normal human dermal fibroblasts: An in vitro wound healing assay

BACKGROUND

Botulinum toxin A (BoNT-A) is widely utilized in the management of hypertrophic and keloid scars. One proposed mechanism for scar prevention involves the inhibition of fibroblast migration in scars by BoNT-A. However, the data regarding the effect of BoNT-A on the migration of normal human dermal fibroblasts (NHDF) is limited.

OBJECTIVES

The aim of this study was to investigate the inhibitory effect of different types and dilutions of BoNT-A on the migration of NHDF.

METHODS

In vitro scratch wound assay, NHDF cells were cultured, incubated, and subjected to scratching using a sterile tip. Subsequently, the scratched NHDF monolayer was treated with different types of BoNT-A, including onabotulinumtoxinA (ONA), incobotulinumtoxinA (INCO), prabotulinumtoxinA (PRABO), or letibotulinumtoxinA (LETI), at varying concentrations of 10, 20, 25, 40, 50, and 100 units/milliliter (U/mL). Additionally, abobotulinumtoxinA (ABO) was administered at concentrations of 33, 50, 66, 71, 100, 150, 300, and 500 U/mL. Normal saline solution (NSS) served as a negative control. The extent of NHDF migration was evaluated by comparing each dilution of BoNT-A with the controls using high-content imaging at the 48-h time point. Furthermore, the viability of the of NHDF was assessed.

RESULTS

The concentrations of 25, 40, and 50 U/mL of ONA (p < 0.001) and 25 U/mL of LETI (p < 0.05) demonstrated significantly inhibited NHDF migration in comparison to the control group. Conversely, all dilutions of PRABO, INCO, and ABO exhibited comparable NHDF migration to that of the control group. Regarding NHDF viability, no significant decrease was observed across any of the BoNT-A types and dilutions.

CONCLUSION

Different types and dilutions of BoNT-A demonstrated variable inhibitory effects on NHDF migration in vitro. The selection of BoNT-A formulation may significantly impact the clinical outcome of scar prevention related to fibroblast migration.

Embracing the Versatility of Botulinum Neurotoxins in Conventional and New Therapeutic Applications

Botulinum neurotoxins (BoNTs) have been used for almost half a century in the treatment of excessive muscle contractility. BoNTs are routinely used to treat movement disorders such as cervical dystonia, spastic conditions, blepharospasm, and hyperhidrosis, as well as for cosmetic purposes. In addition to the conventional indications, the use of BoNTs to reduce pain has gained increased recognition, giving rise to an increasing number of indications in disorders associated with chronic pain. Furthermore, BoNT-derived formulations are benefiting a much wider range of patients suffering from overactive bladder, erectile dysfunction, arthropathy, neuropathic pain, and cancer. BoNTs are categorised into seven toxinotypes, two of which are in clinical use, and each toxinotype is divided into multiple subtypes. With the development of bioinformatic tools, new BoNT-like toxins have been identified in non-Clostridial organisms. In addition to the expanding indications of existing formulations, the rich variety of toxinotypes or subtypes in the wild-type BoNTs associated with new BoNT-like toxins expand the BoNT superfamily, forming the basis on which to develop new BoNT-based therapeutics as well as research tools. An overview of the diversity of the BoNT family along with their conventional therapeutic uses is presented in this review followed by the engineering and formulation opportunities opening avenues in therapy.

Botulinum toxin type A inhibits M1 macrophage polarization by deactivation of JAK2/STAT1 and IκB/NFκB pathway and contributes to scar alleviation in aseptic skin wound healing

The non-neuronal and non-muscular effects of botulinum toxin type A (BTXA) on scar reduction has been discovered. This study was designed to investigate the effects of BTXA on macrophages polarization during the early stage of skin repair. A skin defect model was established on the dorsal skin of SD rats. BTXA was intracutaneous injected into the edge of wound immediately as the model was established. Histological examinations were performed on scar samples. Raw 264.7 was selected as the cell model of recruited circulating macrophages, and was induced for M1 polarization by LPS. Identify the signaling pathways that primarily regulated M1 polarization and respond to BTXA treatment. Application of BTXA at early stage of injury significantly reduced the scar diameter without delaying wound closure. BTXA treatment improved fiber proliferation and arrangement, and inhibited angiogenesis in scar granular tissue. The number of M1 macrophages and the levels of pro-inflammation were decreased after treated with BTXA in scar tissues. LPS activated JAK2/STAT1 and IκB/NFκB pathways were downregulated by BTXA, as well as LPS induced M1 polarization. At early stage of skin wound healing, injection of BTXA effectively reduced the number of M1 macrophages and the levels of pro-inflammatory mediators which contributes to scar alleviation. BTXA resisted the M1 polarization of macrophages induced by LPS via deactivating the JAK2/STAT1 and IκB/NFκB pathways.

Neurotoxin in the Lower Third of the Face

Botulinum toxin A (BT) is the most required treatment in face rejuvenation. However, applications of BT on the lower third are off-label and specific tips for the treatment of this area should be taken into account to achieve best results. In the current study, literature concerning BT treatment of lower face has been revised and summarized according to anatomy and indications, tips, and complications. BT treatment of the lower face has been reported to be effective and safe when performed with adequate knowledge of anatomy and techniques.

Quantitative Assessment of the Effects of Botulinum Toxin on Skin Perfusion by Laser Doppler Flowmetry: A Clinical Trial

Several studies reported an increase in skin glow, pore shrinkage, and an improvement in oily skin with its mesobotox-like use. The authors aimed to determine the extent of late changes in skin perfusion in the superficial dermis when Botulinium toxin A (Btx-A) is injected into the skin with mesotherapy, independent of any stimulant and surgery, using a laser Doppler flowmeter for analysis. Btx-A was applied to the right cheek and saline mesotherapy to the left cheeks of a total of 9 subjects. Two weeks later, their contribution to skin circulation was measured by the laser Doppler flowmeter. Although it was more on the side where Btx-A was applied, an increase in vascularity was observed on both sides of the subjects and no statistical difference could be found between the right and left cheeks in the late period.

Efficacy of Botulinum Toxin Type A for Prevention of Post-Mastectomy Scar in Transmen: A Prospective, Randomized Study

BACKGROUND

Subcutaneous mastectomies in transmen have been gaining popularity. However, post-operative scars are an inevitable consequence. Recently, Botulinum neurotoxin A (BoNT-A) has shown positive effects in scar prevention. The objective of this study is to investigate the effectiveness of BoNT-A in scar prevention.

METHODS

Fifteen patients who had undergone subcutaneous mastectomy were included. At 14 days post-surgery, either incoBoNT-A or a placebo was injected into the scar on each side. The primary outcome assessment measured the scar's severity using the Vancouver Scar Scale (VSS) and the Patient and Observer Scar Assessment Scale (POSAS). The secondary outcome assessment evaluated the scar's color using a standard measurement device. Outcome assessments were conducted until 6 months post-surgery.

RESULTS

There were significantly lower VSS scores in the BoNT-A group compared to the placebo at the end of the study (7.43 ± 0.26 vs. 8.82 ± 0.26, p < 0.001). The objective assessment revealed a statistically significant decrease in redness values in the BoNT-A group compared to the placebo at 3 and 6 months.

CONCLUSION

BoNT-A has demonstrated effectiveness in scar prevention by reducing the severity of postoperative scar formation and improving overall scar appearance.

Microtoxin for Improving Pore Size, Skin Laxity, Sebum Control, and Scars: A Roundtable on Integrating Intradermal Botulinum Toxin Type A Microdoses Into Clinical Practice

BACKGROUND

In aesthetic clinical practice, botulinum toxin type A (BoNT-A) is best known for its use as a neuromodulator for the treatment of dynamic facial lines; however, when injected intradermally as microdroplets, BoNT-A can improve skin quality and overall skin appearance.

OBJECTIVES

To discuss key aspects of microtoxin use in clinical practice and provide expert guidance on utilization.

METHODS

As part of a continuing medical education lecture series and roundtable, the authors discussed key aspects of microtoxin patient selection, injection technique, and safety.

RESULTS

The experiences of expert faculty are shared here. Clinical experience is consistent with reported data. Microtoxin can be used to reduce pore size, sebum production, rosacea, acne, and fine lines, and to improve jawline and neck definition. Intradermal injection can also be employed for the improvement of transverse neck lines as well as for the safe prevention and management of scars and keloids.

CONCLUSIONS

Expanding the use of BoNT-A, a predictable, minimally invasive, and affordable treatment to address commonly encountered complaints is appealing. The authors have found that making patients aware of microtoxin as a treatment option results in an increased interest in and utilization of BoNT-A, and high satisfaction among appropriately selected patients.

Long‐pulsed Nd: YAG laser (1064 nm) versus intralesional botulinum toxin type (A) in acne vulgaris therapy: a split face study

BACKGROUND

Acne can be considered more than a cosmetic concern due to its large impact on patients' quality of life. There are various therapeutic options for inflammatory acne, but inconvenience and undesirable side effects prompted a search for more acceptable treatments. This study aimed to compare the clinical efficacy and safety of long-pulsed Nd: YAG laser 1064 nm versus intralesional botulinum toxin type-A (BTX-A) in inflammatory acne therapy.

METHODS

A prospective randomized split-face comparative study involved 30 patients with inflammatory acne. Each patient received long-pulsed Nd: YAG 1064 nm laser on one side, and intralesional BTX-A on the other side, monthly until improvement or maximum three sessions. Cases were assessed by acne lesions counting and grading of severity by Investigator's Global Assessment of acne (IGAs) at baseline, each session, and after 3 months follow-up.

RESULTS

A highly statistically significant improvement in lesions count and IGAs for both sides was observed, with statistically non-significant difference between both sides at end of treatment sessions. While, after 3 months follow-up, there was a more significant improvement at laser side.

CONCLUSION

Both long-pulsed Nd: YAG laser 1064 nm and intralesional BTX-A are safe and effective for acne therapy. Nd-YAG laser has a more prolonged efficacy and lower recurrence rate than intralesional BTX-A.

Botulinum Neurotoxin Type A Directly Affects Sebocytes and Modulates Oleic Acid-Induced Lipogenesis

Excess sebum (seborrhea) results in oily skin and is associated with large pore size and acne. Studies in healthy, seborrheic volunteers have reported that intradermal injection of commercial preparations of botulinum neurotoxin type A (BoNT/A) (onabotulinumtoxinA, abobotulinumtoxinA, and incobotulinumtoxinA) reduced sebum production, and thus, skin oiliness and pore size. The mechanism for these effects has not been fully elucidated; however, several theories involving direct or indirect effects of BoNT/A on neuronal and/or dermal cells (e.g., sebocytes) have been proposed. In the present study, we evaluated the direct effect of native research grade BoNT/A complex, a commercial preparation of BoNT/A (onabotA), and BoNT/A variants on sebocyte lipogenesis using an in vitro sebocyte cell model. We show that picomolar concentrations of BoNT/A (BoNT/A complex: half maximal effective concentration [EC₅₀] = 24 pM; BoNT/A 150 kDa: EC₅₀ = 34 pM) modulate sebocyte lipogenesis and reduce oleic acid-induced sebocyte differentiation, lipogenesis, and holocrine-like secretion. Comparative studies with the binding domain of BoNT/A, which lacks enzymatic activity, show that this effect is independent of the enzymatic activity of BoNT/A and likely occurs via sebocyte cell surface receptors (e.g., fibroblast growth factor receptors). Overall, these results shed light on the potential mechanism of action and rationale for use of BoNT/A for treatment of sebum-related conditions.

How Does Botulinum Toxin Inhibit Itch?

Two decades after reports of the anti-pruritic effects of botulinum neurotoxins (BoNTs), there is still no approved product for the anti-itch indication of BoNTs, and most clinical case reports still focus on the off-label use of BoNTs for various itchy conditions. Few randomized clinical trials have been conducted with controversial results, and the beneficial effects of BoNTs against itch are mainly based on case studies and case series. These studies are valuable in presenting the potential application of BoNTs in chronic pruritic conditions, but due to the nature of these studies, they are categorized as providing lower levels of evidence or lower grades of recommendation. To obtain approval for the anti-pruritic indication of BoNTs, higher levels of evidence are required, which can be achieved through conducting large-scale and well-designed studies with proper control groups and established careful and reliable primary and secondary outcomes. In addition to clinical evidence, presenting the mechanism-based antipruritic action of BoNTs can potentially strengthen, accelerate, and facilitate the current efforts towards further investments in accelerating the field towards the potential approval of BoNTs for itchy conditions. This review, therefore, aimed to provide the state-of-the-art mechanisms underlying the anti-itch effect of BoNTs from basic studies that resemble various clinical conditions with itch as a hallmark. Evidence of the neuronal, glial, and immune modulatory actions of BoNTs in reducing the transmission of itch are presented, and future potential directions are outlined.

Nociceptor Neurons are Involved in the Host Response to Escherichia coli Urinary Tract Infections

Purpose

Urinary tract infections (UTIs) can evoke a rapid host immune response leading to bladder inflammation and epithelial damage. Neuroimmune interactions are critical for regulating immune function in mucosal tissues. Yet the role of nociceptor neurons in bladder host defense has not been well defined. This study aimed to explore the interaction between nociceptor neurons and bladder immune system during UTIs.

Methods

In this study, whether uropathogenic Escherichia coli (UPEC) and lipopolysaccharide (LPS) can directly stimulate nociceptor neurons was detected. Female C57BL/6J mice were treated with high dose of capsaicin, a high-affinity TRPV1 agonist, to ablate nociceptor neurons. Bladder inflammation, barrier epithelial function and bladder immune cell infiltration were assessed after UPEC infection. The level of neuropeptide calcitonin gene-related peptide (CGRP) in infected bladder was detected. Furthermore, the effects of CGRP on neutrophils and macrophages were evaluated both in vitro and in vivo.

Results

We found that UPEC and its pathogenic factor LPS could directly excite nociceptor neurons, releasing CGRP into infected bladder, which suppressed the recruitment of neutrophils, the polarization of macrophages and the killing function of UPEC. Both Botulinum neurotoxin A (BoNT/A) and BIBN4096 (CGRP antagonism) blocked neuronal inhibition and prevented against UPEC infection.

Conclusion

The present study showed a novel mechanism by which UPEC stimulated the secretion of CGRP from nociceptor neurons to suppress innate immunity.

Toxicology and pharmacology of botulinum and tetanus neurotoxins: an update

Tetanus and botulinum neurotoxins cause the neuroparalytic syndromes of tetanus and botulism, respectively, by delivering inside different types of neurons, metalloproteases specifically cleaving the SNARE proteins that are essential for the release of neurotransmitters. Research on their mechanism of action is intensively carried out in order to devise improved therapies based on antibodies and chemical drugs. Recently, major results have been obtained with human monoclonal antibodies and with single chain antibodies that have allowed one to neutralize the metalloprotease activity of botulinum neurotoxin type A1 inside neurons. In addition, a method has been devised to induce a rapid molecular evolution of the metalloprotease domain of botulinum neurotoxin followed by selection driven to re-target the metalloprotease activity versus novel targets with respect to the SNARE proteins. At the same time, an intense and wide spectrum clinical research on novel therapeutics based on botulinum neurotoxins is carried out, which are also reviewed here.

The Isolated Mouse Jejunal Afferent Nerve Assay as a Tool to Assess the Effect of Botulinum Neurotoxins in Visceral Nociception

For the past two decades, botulinum neurotoxin A (BoNT/A) has been described as a strong candidate in the treatment of pain. With the production of modified toxins and the potential new applications at the visceral level, there is a real need for tools allowing the assessment of these compounds. In this study, we evaluated the jejunal mesenteric afferent nerve assay to investigate BoNT/A effects on visceral nociception. This ex vivo model allowed the continuous recording of neuronal activity in response to various stimuli. BoNT/A was applied intraluminally during three successive distensions, and the jejunum was distended every 15 min for 3 h. Finally, samples were exposed to external capsaicin. BoNT/A intoxication was validated at the molecular level with the presence of cleaved synaptosomal-associated protein of 25 (SNAP25) in nerve terminals in the mucosa and musculosa layers 3 h after treatment. BoNT/A had a progressive inhibitory effect on multiunit discharge frequency induced by jejunal distension, with a significant decrease from 1 h after application without change in jejunal compliance. The capsaicin-induced discharge was also affected by the toxin. This assay allowed the description of an inhibitory effect of BoNT/A on afferent nerve activity in response to distension and capsaicin, suggesting BoNT/A could alleviate visceral nociception.

Efficacy of Botulinum Toxin A for Scar Prevention After Breast Augmentation: A Randomized Double-Blind Intraindividual Controlled Trial

BACKGROUND

Botulinum toxin A benefits postsurgical scar prevention by reducing wound edge tension and inhibiting in vitro scar tissue fibrosis.

OBJECTIVE

To investigate the efficacy of botulinum toxin Type A (BTX) in improving inframammary scar appearance after primary breast augmentation.

MATERIALS AND METHODS

A prospective, double-blinded, randomized controlled trial was performed with 27 participants receiving primary augmentation mammoplasty with inframammary incisions. After skin closure, intradermal injections of BTX were administered to 1 (treated) side of the inframammary incision. The contralateral side was the control. Scars were evaluated at 3 months, 6 months, and 9 months using the Patient and Observer Scar Assessment Scale and multispectral imaging analysis.

RESULTS

Overall, 22 patients completed the study. There were no significant subjective differences between the treated and control sides except the patient's treated side had significantly higher scores than the control side at 9 months. The treated side showed significantly smaller scar widths at 6 months and 9 months (p < .001) and better scar surface textures at 9 months (p = .003) than the control side.

CONCLUSION

Subjectively, intradermal BTX injection immediately after breast augmentation skin closure caused no significant differences. Objectively, scar width and texture significantly improved at 6 months and 9 months.

A novel treatment for prevention of post-traumatic elbow stiffness using onaBotulinum toxin type A: a prospective placebo controlled randomized trial

Approximately 30% of all upper extremity fractures are elbow fractures which may result elbow stiffness. This study aimed to investigate the efficacy of onaBotulinum Toxin type A injection to prevent post-traumatic pain and elbow-stiffness. All patients were included who presented to a single surgeon with supracondylar/ intraarticular distal humerus fractures, proximal ulna and radius fractures. The study was developed in a randomized placebo controlled study between 2003-2007. The Disabilities of the Arm, Shoulder, and Hand (DASH) score as well as the arc-of-motion (AOM) were assessed after three, six, twelve-months and final follow up for evaluation. Of the 31-patients included, 15-patients (48.4%) received Botox injections. In all patients no complication was observed when injecting a dosage 100-units for the brachialis and biceps brachii muscles. Furthermore, it was an effective method to prevent post-traumatic elbow stiffness, lasting six- months. Significant differences in DASH, VAS-score and ROM after three-months between the Botox and control group (DASH 21.6±11.0 vs. 55.3±11.0 ; VAS 1.2±5.2 vs. 5.7±21.9 ; ROM 103±7.6 vs. 73±6.3 ; p>0.05) were identified in the prospective group. Botulinum toxin is a safe, reliable and effective treatment to prevent post-traumatic elbow stiffness. Our study demonstrates improved early range-of- motion (p<0.05), better extension after 6 weeks and improved functional outcome including VAS and DASH score (p<0.05).

Neurocosmetics in Skincare—The Fascinating World of Skin–Brain Connection: A Review to Explore Ingredients, Commercial Products for Skin Aging, and Cosmetic Regulation

The “modern” cosmetology industry is focusing on research devoted to discovering novel neurocosmetic functional ingredients that could improve the interactions between the skin and the nervous system. Many cosmetic companies have started to formulate neurocosmetic products that exhibit their activity on the cutaneous nervous system by affecting the skin’s neuromediators through different mechanisms of action. This review aims to clarify the definition of neurocosmetics, and to describe the features of some functional ingredients and products available on the market, with a look at the regulatory aspect. The attention is devoted to neurocosmetic ingredients for combating skin stress, explaining the stress pathways, which are also correlated with skin aging. “Neuro-relaxing” anti-aging ingredients derived from plant extracts and neurocosmetic strategies to combat inflammatory responses related to skin stress are presented. Afterwards, the molecular basis of sensitive skin and the suitable neurocosmetic ingredients to improve this problem are discussed. With the aim of presenting the major application of Botox-like ingredients as the first neurocosmetics on the market, skin aging is also introduced, and its theory is presented. To confirm the efficacy of the cosmetic products on the market, the concept of cosmetic claims is discussed.

Botulinum toxin injections as an effective treatment for patients with intertriginous Hailey-Hailey or Darier disease: an open-label 6-month pilot interventional study

BACKGROUND

Patients with Hailey-Hailey and Darier diseases present with disabling inflammatory lesions located in large skin folds, which are often exacerbated or induced by sweating. Quality of life is highly impaired because of pain and recurrent skin infections. An improvement in skin lesions after botulinum toxin A injections has previously been reported in some patients but no prospective interventional studies are available. The aim of this open-label, 6-month, interventional pilot study (NCT02782702) was to evaluate the effectiveness and safety of botulinum toxin A for patients with moderate to very severe skin lesions located in folds.

RESULTS

Thirty patients (26 Hailey-Hailey/4 Darier) were included. Botulinum toxin A proved effective within the first month in two-thirds of patients, taking all study parameters (itchiness, cutaneous pain, sweating and odour, infections, psychosocial impairment and quality of life) into account and persisted during the 6-month follow-up period. No patient was classed as a BtxA non-responder, but 11 (37%) Hailey-Hailey patients (the most severe ones), experienced a relapse during the study. No serious side effects were reported. Mild transient clear fluid discharge at the site of the injections was reported for 27% of patients.

CONCLUSIONS

Botulinic toxin seems to be an effective and safe treatment for Hailey-Hailey and Darier diseases. Nevertheless, it may prove insufficient for the severest of Hailey-Hailey cases and could be considered as supplementary to other conventional treatments. Further studies are required to confirm our results on larger Darier cohorts.

Botulinum toxin in treating Hailey-Hailey disease: A systematic review

BACKGROUND

Hailey-Hailey disease is a rare disorder characterized by recurrent painful blistering, erosions, maceration in the intertriginous regions. Botulinum toxin has been used in the treatment of Hailey-Hailey disease.

AIMS

This study aimed to examine all published articles on botulinum toxin in the treatment of Hailey-Hailey disease, and to evaluate its efficacy and safety.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science were used to identify eligible articles on August 8, 2020. The searching strategy was "(Hailey Hailey or Hailey-Hailey or pemphigus) and botulinum."

RESULTS

Sixteen articles including 38 patients described the use of botulinum toxin in treating Hailey-Hailey disease. Only one case had no response, while the other patients all had partial or complete remission. No side effects were reported. Nine articles including 10 patients mainly described other treatment options, and the patients were only treated with botulinum toxin previously. Their responses to botulinum toxin were limited: one was mild improvement, one was partial response, and the other eight failed.

CONCLUSION

Botulinum toxin is not almighty, but a promising alternative option. We recommend botulinum toxin as an adjuvant or supplemental treatment modality for severe and recalcitrant Hailey-Hailey disease. Larger studies are warranted to confirm its efficacy, safety, long-term effects, and cost performance.

Distinctions in the Management, Patient Impact, and Clinical Profiles of Pachyonychia Congenita Subtypes

Introduction

Pachyonychia congenita (PC) is a rare dermatosis that confers lifelong physical and emotional morbidities in affected patients. However, the clinical findings, treatments, and psychosocial impact of this disease have not been adequately described. The International PC Research Registry (IPCRR), a multinational initiative to collect data on PC patients, has allowed an opportunity to distinguish the salient features of this disease. We aimed to characterize the breadth and extent of nail disease, treatments, and quality of life in PC patients, and to describe any significant differences in clinical presentation or treatment of PC subtypes.

Methods

The most recent IPCRR patient survey data consisting of an 857-response questionnaire and a 102-response addendum were analyzed in a retrospective analysis. The survey data were collected as part of a multinational, multicenter initiative and comprise the largest representative population of PC to date. Participants (survey respondents) were included in the study based on questionnaire responses and a genetic confirmation of having a PC subtype.

Results

A total of 857 survey responses were collected. Genetic variations among PC subtypes influence nail disease onset and severity of symptoms. Nail disease negatively impacts patients' emotional health, especially during the adolescent and young adult years. Nail treatment tools vary little in terms of effectiveness and acquired infection rates.

Conclusion and Discussion

Patients with different PC subtypes have distinct clinical nail presentations and psychosocial impact. Genetic testing should be used to confirm PC diagnoses. Further characterization of PC, especially the rarer subtypes, may allow for more individualized patient education.

Therapeutic Use of Botulinum Neurotoxins in Dermatology: Systematic Review

Botulinum toxin is a superfamily of neurotoxins produced by the bacterium Clostridium Botulinum with well-established efficacy and safety profile in focal idiopathic hyperhidrosis. Recently, botulinum toxins have also been used in many other skin diseases, in off label regimen. The objective of this manuscript is to review and analyze the main therapeutic applications of botulinum toxins in skin diseases. A systematic review of the published data was conducted, following Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Botulinum toxins present several label and off-label indications of interest for dermatologists. The best-reported evidence concerns focal idiopathic hyperhidrosis, Raynaud phenomenon, suppurative hidradenitis, Hailey–Hailey disease, epidermolysis bullosa simplex Weber–Cockayne type, Darier’s disease, pachyonychia congenita, aquagenic keratoderma, alopecia, psoriasis, notalgia paresthetica, facial erythema and flushing, and oily skin. Further clinical trials are still needed to better understand the real efficacy and safety of these applications and to standardize injection and doses protocols for off label applications.

Engineering Botulinum Neurotoxins for Enhanced Therapeutic Applications and Vaccine Development

Botulinum neurotoxins (BoNTs) show increasing therapeutic applications ranging from treatment of locally paralyzed muscles to cosmetic benefits. At first, in the 1970s, BoNT was used for the treatment of strabismus, however, nowadays, BoNT has multiple medical applications including the treatment of muscle hyperactivity such as strabismus, dystonia, movement disorders, hemifacial spasm, essential tremor, tics, cervical dystonia, cerebral palsy, as well as secretory disorders (hyperhidrosis, sialorrhea) and pain syndromes such as chronic migraine. This review summarizes current knowledge related to engineering of botulinum toxins, with particular emphasis on their potential therapeutic applications for pain management and for retargeting to non-neuronal tissues. Advances in molecular biology have resulted in generating modified BoNTs with the potential to act in a variety of disorders, however, in addition to the modifications of well characterized toxinotypes, the diversity of the wild type BoNT toxinotypes or subtypes, provides the basis for innovative BoNT-based therapeutics and research tools. This expanding BoNT superfamily forms the foundation for new toxins candidates in a wider range of therapeutic options.

Bioactivity of abobotulinum toxin is preserved till 2 weeks upon storage at room temperature: Half body comparative study on rabbit model

BACKGROUND

Breakages of the cold chain of botulinum neurotoxin A (BONT-A) preparations is not a rare event and occurs due to several unexpected and unintentional reasons during daily practice and intervention schedules could not be proposed due to the lack of data.

OBJECTIVE

To investigate the heat stability of abobotulinum toxin A (AboBONT-A) in terms of efficacy and duration of action upon storage at room temperature (25°C) for 2, 4, and 8 weeks.

METHODS AND MATERIALS

Twenty rabbits were divided into four groups and received an injection of ideally stored AboBONT-A (Group 1) and stored AboBONT-A for 2 (Group 2), 4 (Group 3), and 8 weeks (Group 4) at room temperature into the anterior auricular muscle. All rabbits were followed up and photographed by weekly for 16 weeks. Grade of paralysis was evaluated by using a modified visual scoring system.

RESULTS

No significant alteration was found in initial potency of stored AboBONT-A at room temperature for up to 4 weeks. Storage at room temperature for 2 weeks did not affect the duration of action (group 2; P = .69), and faster recovery was observed in group 3 and group 4.

CONCLUSION

The bioactivity of AboBONT-A is not altered till 2 weeks upon storage at room temperature.

Botulinum toxin type A in the treatment of Raynaud's phenomenon

Raynaud's phenomenon is a vasospastic disorder clinically characterized by cold or stress-induced discoloration of the skin, pain and ulcers of the fingers or toes. Although this phenomenon might be self-limiting, there is a subgroup of patients requiring a therapeutic approach. The majority of patients do well on conservative measures; however, there is also a subgroup requiring systemic treatment. The efficacy of these systemic treatments is currently not thoroughly investigated. Furthermore, no uniform guidelines exist regarding the choice for a treatment option. In the past several years, several reports have shown the benefits of botulinum toxin for the treatment of Raynaud's phenomenon. In this case series, we report our experience with botulinum toxin type A in the treatment of Raynaud's phenomenon.

The effect of botulinum toxin type A in different dilution on the contraction of fibroblast-In vitro study

BACKGROUND

Botulinum toxin type A (BoNT-A) may directly remodel dermal tissues or induce a loss of normal morphology and cytoplasmic retraction and spread. Intradermal injection was claimed to produce a dermo-lifting effect, including midface lifting by using low concentration with variable dilution.

OBJECTIVE

To understand how intradermal BoNT-A achieves tissue lifting, we examined different type of BoNT-A and their effects on dermal fibroblast contraction.

METHODS

Normal human dermal fibroblasts were treated with onabotulinumtoxin (ONA), abobotulinumtoxin (ABO), prabotulinumtoxinA (PRABO), incobotulinumtoxinA (INCO), and letibotulinumtoxin A (LETI) in dilutions used in real-world practice. Fifty fibroblasts per dilution were photographed and measured the length to demonstrate their contraction every 2 hours from baseline (0 hours) to 12 hours post-treatment.

RESULTS

ONA did not significantly decrease fibroblast lengths, at any timepoint or dilution. At 1:7 dilution ratios, ABO decreased fibroblast lengths after 2 hours and significantly after 10-12 hours. At 1:7, 1:8, 1:9, and 1:10 dilution, PRABO decreased length, and most rapidly at 1:7 and 1:8. At 1:6, 1:8, 1:9, and 1:10 dilution, INCO decreased lengths almost immediately. At 1:6 dilution, INCO decreased lengths almost immediately. At 1:7 dilution, INCO decreased lengths after 2-4 hours, while at 1:8, 1:9, and 1:10 dilution, INCO decreased lenghts nearly imediately. LETI decreased lengths at all dilutions except 1:9, with near-immediate effects at 1:6, 1:7, 1:8, and 1:10. At 1:4 dilution, LETI decreased lengths from 1 hour.

CONCLUSIONS

Different commercial preparations of BoNT-A toxins cause different fibroblast contractions in vitro. Product selection and dilution used may affect the clinical outcome of intradermal injection of BoNT-A for face lifting.

New trends in botulinum toxin use in dermatology

Background

Recent studies have highlighted new botulinum neurotoxin (BoNT) applications in the field of dermatology.

Objective

To review current knowledge of BoNT use in dermatology.

Methods

The literature of the last 5 five years has been reviewed.

Results

We describe interesting protocols of BoNT treatment for hyperhidrosis (HH), hypertrophic scars and keloids, Raynaud phenomenon, facial flushing, oily skin, psoriasis, Hailey-Hailey disease, and cutaneous lesions like painful lesions and periorbital syringomas.

Conclusions

Several skin conditions eligible for BoNT treatment have been described. After the wide application for HH treatment, scars as well as vascular and inflammatory skin disorders, oily skin and cutaneous lesions represent fields of application of BoNT.

Variability of Botulinum Toxins: Challenges and Opportunities for the Future

Botulinum neurotoxins (BoNTs) are the most potent known toxins, and are therefore classified as extremely harmful biological weapons. However, BoNTs are therapeutic drugs that are widely used and have an increasing number of applications. BoNTs show a high diversity and are divided into multiple types and subtypes. Better understanding of the activity at the molecular and clinical levels of the natural BoNT variants as well as the development of BoNT-based chimeric molecules opens the door to novel medical applications such as silencing the sensory neurons at targeted areas and dermal restoration. This short review is focused on BoNTs’ variability and the opportunities or challenges posed for future clinical applications.

Effects of Botulinum Toxin A Observed During Early Scar Formation Following Rhytidectomy: Controlled, Double-Blinded Pilot Study

Several past studies have suggested there are benefits to using botulinum neurotoxin type A (BoNTA) for improving the aesthetic appearance of established scars. This article describes a study on the prophylactic use of BoNTA for controlling scar formations as they occur. It is based on a small, double-blinded, controlled group of patients having just undergone a facelift procedure. The results suggest that the use of BoNTA just after surgery yield both quantitative and qualitative aesthetic benefits, and the data provide some guidance on optimal doses.

Engineering Botulinum Toxins to Improve and Expand Targeting and SNARE Cleavage Activity

Botulinum neurotoxins (BoNTs) are highly successful protein therapeutics. Over 40 naturally occurring BoNTs have been described thus far and, of those, only 2 are commercially available for clinical use. Different members of the BoNT family present different biological properties but share a similar multi-domain structure at the molecular level. In nature, BoNTs are encoded by DNA in producing clostridial bacteria and, as such, are amenable to recombinant production through insertion of the coding DNA into other bacterial species. This, in turn, creates possibilities for protein engineering. Here, we review the production of BoNTs by the natural host and also recombinant production approaches utilised in the field. Applications of recombinant BoNT-production include the generation of BoNT-derived domain fragments, the creation of novel BoNTs with improved performance and enhanced therapeutic potential, as well as the advancement of BoNT vaccines. In this article, we discuss site directed mutagenesis, used to affect the biological properties of BoNTs, including approaches to alter their binding to neurons and to alter the specificity and kinetics of substrate cleavage. We also discuss the target secretion inhibitor (TSI) platform, in which the neuronal binding domain of BoNTs is substituted with an alternative cellular ligand to re-target the toxins to non-neuronal systems. Understanding and harnessing the potential of the biological diversity of natural BoNTs, together with the ability to engineer novel mutations and further changes to the protein structure, will provide the basis for increasing the scope of future BoNT-based therapeutics.

Blocking Neuronal Signaling to Immune Cells Treats Streptococcal Invasive Infection

The nervous system, the immune system, and microbial pathogens interact closely at barrier tissues. Here, we find that a bacterial pathogen, Streptococcus pyogenes, hijacks pain and neuronal regulation of the immune response to promote bacterial survival. Necrotizing fasciitis is a life-threatening soft tissue infection in which "pain is out of proportion" to early physical manifestations. We find that S. pyogenes, the leading cause of necrotizing fasciitis, secretes streptolysin S (SLS) to directly activate nociceptor neurons and produce pain during infection. Nociceptors, in turn, release the neuropeptide calcitonin gene-related peptide (CGRP) into infected tissues, which inhibits the recruitment of neutrophils and opsonophagocytic killing of S. pyogenes. Botulinum neurotoxin A and CGRP antagonism block neuron-mediated suppression of host defense, thereby preventing and treating S. pyogenes necrotizing infection. We conclude that targeting the peripheral nervous system and blocking neuro-immune communication is a promising strategy to treat highly invasive bacterial infections. VIDEO ABSTRACT.