Botulinum Toxin: An Update on Pharmacology and Newer Products in Development

Neurobiological mechanisms of botulinum neurotoxin-induced analgesia for neuropathic pain

Botulinum neurotoxins (BoNTs) are a family of neurotoxins produced by Clostridia and other bacteria that induce botulism. BoNTs are internalized into nerve terminals at the site of injection and cleave soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins to inhibit the vesicular release of neurotransmitters. BoNTs have been approved for multiple therapeutic applications, including the treatment of migraines. They have also shown efficacies for treating neuropathic pain, such as diabetic neuropathy, and postherpetic and trigeminal neuralgia. However, the mechanisms underlying BoNT-induced analgesia are not well understood. Peripherally administered BoNT is taken up by the nerve terminals and reduces the release of glutamate, calcitonin gene-related peptide, and substance P, which decreases neurogenic inflammation in the periphery. BoNT is retrogradely transported to sensory ganglia and central terminals in a microtubule-dependent manner. BoNTs decrease the expression of pronociceptive genes (ion channels or cytokines) from sensory ganglia and the release of neurotransmitters and neuropeptides from primary afferent central terminals, which likely leads to decreased central sensitization in the dorsal horn of the spinal cord or trigeminal nucleus. BoNT-induced analgesia is abolished after capsaicin-induced denervation of transient receptor potential vanilloid 1 (TRPV1)-expressing afferents or the knockout of substance P or the neurokinin-1 receptor. Although peripheral administration of BoNT leads to changes in the central nervous system (e.g., decreased phosphorylation of glutamate receptors in second-order neurons, reduced activation of microglia, contralateral localization, and cortical reorganization), whether such changes are secondary to changes in primary afferents or directly mediated by trans-synaptic, transcytotic, or the hematogenous transport of BoNT is controversial. To enhance their therapeutic potential, BoNTs engineered for specific targeting of nociceptive pathways have been developed to treat chronic pain. Further mechanistic studies on BoNT-induced analgesia can enhance the application of native or engineered BoNTs for neuropathic pain treatment with improved safety and efficacy.

Botulinum Toxin Accessory Proteins: Are They Just an Accessory?

BACKGROUND

Botulinum neurotoxins produced by Clostridium botulinum consist of a complex of a core neurotoxin protein and one or more nontoxin accessory proteins. The accessory proteins are generally thought to protect the neurotoxin from the gastric environment in botulism poisoning, dissociating away upon absorption. Other than their questionable immunogenicity, they are rarely mentioned in botulinum toxin therapy.

OBJECTIVE

To review evidence that accessory proteins potentially play a role in neurotoxin activity.

RESULTS

Evidence suggests that the accessory proteins do not dissociate from the neurotoxin complex and enhance neurotoxin activity. Complexed type A botulinum toxin has dramatically higher endopeptidase activity than noncomplexed neurotoxin. A primary accessory protein, hemagglutinin-33, exhibits this same effect on both type A and type E core neurotoxin proteins, the latter not natively having this accessory protein. A clinical study using an objective computer assessment assay has shown a correlation between type A complex size and glabellar strain reduction, which reflects increasing clinical efficacy. Finally, a systematic review found no correlation between type A complex size and neutralizing antibody formation.

CONCLUSION

Accessory proteins may play a role in the efficacy of botulinum toxin and could remain complexed to the neurotoxin for longer than previously reported.

Clinical neurophysiology in the treatment of movement disorders: IFCN handbook chapter

In this review, different aspects of the use of clinical neurophysiology techniques for the treatment of movement disorders are addressed. First of all, these techniques can be used to guide neuromodulation techniques or to perform therapeutic neuromodulation as such. Neuromodulation includes invasive techniques based on the surgical implantation of electrodes and a pulse generator, such as deep brain stimulation (DBS) or spinal cord stimulation (SCS) on the one hand, and non-invasive techniques aimed at modulating or even lesioning neural structures by transcranial application. Movement disorders are one of the main areas of indication for the various neuromodulation techniques. This review focuses on the following techniques: DBS, repetitive transcranial magnetic stimulation (rTMS), low-intensity transcranial electrical stimulation, including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), and focused ultrasound (FUS), including high-intensity magnetic resonance-guided FUS (MRgFUS), and pulsed mode low-intensity transcranial FUS stimulation (TUS). The main clinical conditions in which neuromodulation has proven its efficacy are Parkinson's disease, dystonia, and essential tremor, mainly using DBS or MRgFUS. There is also some evidence for Tourette syndrome (DBS), Huntington's disease (DBS), cerebellar ataxia (tDCS), and axial signs (SCS) and depression (rTMS) in PD. The development of non-invasive transcranial neuromodulation techniques is limited by the short-term clinical impact of these techniques, especially rTMS, in the context of very chronic diseases. However, at-home use (tDCS) or current advances in the design of closed-loop stimulation (tACS) may open new perspectives for the application of these techniques in patients, favored by their easier use and lower rate of adverse effects compared to invasive or lesioning methods. Finally, this review summarizes the evidence for keeping the use of electromyography to optimize the identification of muscles to be treated with botulinum toxin injection, which is indicated and widely performed for the treatment of various movement disorders.

Botulism Cases in Romania-An Overview of 14-Year National Surveillance Data

Botulism is a priority disease worldwide because it has a very severe course of evolution that can lead to death. This paper aims to describe the main epidemiological characteristics of botulism cases confirmed in Romania over 14 years (2007-2020). We performed a retrospective study using the publicly available national surveillance data and reported to the National Institute of Public Health. A total of 325 cases of foodborne botulism were reported in Romania, with no infant or wound botulism. Most of the cases (125, 38.5%) were reported among young adults (25-44 years old), over half (205, 63%) of them living in rural areas. The incriminated food item was identified in 161 cases; in most cases (145, 90%) the food item was prepared in the household. The main food category was represented by meat and meat-based products (94, 68.6%). In almost all cases the identified type was BoNT/B (230/231, 99.5%). Fifteen deaths were recorded, and the case fatality rate was 4.6%. Botulism cases were reported annually in Romania. Surveillance data are essential for implementing control measures and adapting educational campaigns according to existing needs.

Comparative Study on the Duration and Efficacy of Various Botulinum Toxin Type A Injections for Reducing Masseteric Muscle Bite Force and Treating Facial Wrinkles

OBJECTIVE

Botulinum toxin serotype A (BoNT/A) is widely used for minimal invasive aesthetic treatments. Different brands of BoNT/A exhibit structural variations. The aim of this study was to compare the duration and efficacy of various BoNT/A brands available in Thailand for reducing bite force and treating wrinkles.

METHODS

Fifty participants were randomly assigned to one of five groups, with each group receiving a different BoNT/A brand, namely, incobotulinumtoxinA (IncoA), onabotulinumtoxinA (OnaA), abobotulinumtoxinA (AboA), letibotulinumtoxinA (LetiA), and prabotulinumtoxinA (PraboA). BoNT/A was administered to the masseter muscle and the upper face. Bite force was measured before injection and at 2, 4, 8, 12, 16, 20, and 24 weeks post-injection. Evaluation scores for wrinkle improvement were assessed after the treatment.

RESULTS

The most significant reduction in bite force occurred between 2 and 4 weeks post-injection. PraboA demonstrated the most substantial reduction in bite force, while IncoA had the least effect. However, the percentage of bite force reduction did not exhibit statistical significance between BoNT/A types. Additionally, the reduction in bite force for all BoNT/A types was reversed at 4 months post-injection. More than half of the participants experienced improvement beyond 16 weeks.

CONCLUSIONS

The structural differences among BoNT/A brands did not significantly affect the longevity and efficacy of bite force reduction and wrinkle treatment.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: TCTR20211205001 (registered 4 Dec 2021).

The Role of Botulinum Toxin Type-A in Spasticity: Research Trends from a Bibliometric Analysis

Botulinum toxin type-A (BoNT-A) has emerged as a key therapeutic agent for the management of spasticity. This paper presents a comprehensive bibliometric and visual analysis of research concerning BoNT-A treatment of spasticity to elucidate current trends and future directions in this research area. A search was conducted in the Web of Science database for articles focused on the use of BoNT-A in spasticity published between 2000 and 2022. We extracted various metrics, including counts of publications and contributions from different countries, institutions, authors, and journals. Analytical methods in CiteSpace were employed for the examination of co-citations, collaborations, and the co-occurrence of keywords. Our search yielded 1489 publications. Analysis revealed a consistent annual increase in research output. The United States, United Kingdom, and Italy were the leading contributors. The top institution in this research was Assistance Publique Hopitaux, Paris. The journal containing the highest number of relevant publications was Toxins. Key frequently occurring keywords were 'stroke', 'cerebral palsy', 'adult spasticity', and 'upper extremity'. This study identified 12 clusters of keywords and 15 clusters of co-cited references, indicating the main focus areas and emerging themes in this field. This study comprehensively analyzed and summarized trends in BoNT-A research in the field of spasticity over the past 22 years.

Treatment of Frey Syndrome with Botulinum Toxin-A: A Practical Approach from Minor's Test to Injection

Introduction

Frey's syndrome, described by Lucy Frey in 1923, is a unique condition characterized by sweating, flushing, and reddening as a direct response to mastication. This phenomenon results from the aberrant regeneration of postganglionic parasympathetic neurons originating from the auriculotemporal nerve and the subsequent acetylcholine secretion induced by masticatory stimuli. Although rare, this syndrome can have multiple underlying causes and is frequently observed, occurring in up to 65% of cases following lateral parotid resections. Additionally, it can less commonly manifest after neck dissection, facelift procedures, or be associated with diabetes mellitus.

Method

This article outlines a comprehensive diagnostic algorithm for Frey's syndrome, which includes the utilization of the Minor-Starch-Iodine Test. This test is a key component in diagnosing the syndrome and is discussed in detail, providing insights into its procedure and interpretation. Additionally, the gold standard of treatment for established Frey's syndrome, botulinum toxin A, is thoroughly described, including its mechanism of action, administration, and potential side effects.

Discussion

Finally, the article underscores the need for further research to enhance our understanding of Frey's syndrome, leading to better diagnostic methods and more tailored treatment options for patients.

Cellular and molecular mechanisms involved in the analgesic effects of botulinum neurotoxin: A literature review

Botulinum neurotoxins (BoNTs), derived from Clostridium botulinum, have been employed to treat a range of central and peripheral neurological disease. Some studies indicate that BoNT may be beneficial for pain conditions as well. It has been hypothesized that BoNTs may exert their analgesic effects by preventing the release of pain-related neurotransmitters and neuroinflammatory agents from sensory nerve endings, suppressing glial activation, and inhibiting the transmission of pain-related receptors to the neuronal cell membrane. In addition, there is evidence to suggest that the central analgesic effects of BoNTs are mediated through their retrograde axonal transport. The purpose of this review is to summarize the experimental evidence of the analgesic functions of BoNTs and discuss the cellular and molecular mechanisms by which they can act on pain conditions. Most of the studies reviewed in this article were conducted using BoNT/A. The PubMed database was searched from 1995 to December 2022 to identify relevant literature.

Botulinum Toxin to Improve the Prognosis of Skin Transplantation: A Short Narrative Review

Skin transplantation is a traditional and well-established method of repairing skin loss, especially deep second-degree postburn wounds. Complications often happen amid the healing process, including necrosis and skin contracture, which has raised widespread concern from patients and doctors. Since the first recorded medical application of botulinum toxin for strabismus, accumulating evidence has enclosed all-round potential of botulinum toxin, more than aesthetic management. In recent decades, botulinum toxin also has been revealed to improve the prognosis of skin grafts. This literature review aims to briefly summarize the history and latest advances of its use for skin transplantation.

Short-Term Effects of Botulinum Toxin-A Injection on the Medial Gastrocnemius Histological Features in Ambulant Children with Cerebral Palsy: A Longitudinal Pilot Study

Botulinum toxin-A (BoNT-A) injection is known to exert beneficial effects on muscle tone, joint mobility and gait in children with cerebral palsy (CP). However, recent animal and human studies have raised the concern that BoNT-A might be harmful to muscle integrity. In CP-children, the impact of BoNT-A on muscle structure has been poorly studied, and inconsistent results have been reported. This study was aimed at determining the time course effect of a single BoNT-A administration on medial gastrocnemius (MG) morphology in CP-children. MG microbiopsies from 12 ambulant and BoNT-A-naïve CP-children (age, 3.4 (2.3) years, ranging from 2.5 to 7.8 years; seven boys and five girls; GMFCS I = 5, II = 4 and III = 3) were collected before and 3 and 6 months after BoNT-A treatment to analyze the fiber cross-sectional area (fCSA) and proportion; capillarization; and satellite cell (SC) content. Compared with the baseline, the fCSA decreased at 3 months (-14%, NS) and increased at 6 months (+13%, NS). Fiber size variability was significantly higher at 3 months (type I: +56%, p = 0.032; type IIa: +37%, p = 0.032) and 6 months (type I: +69%, p = 0.04; type IIa: +121%, p = 0.032) compared with the baseline. The higher type I proportion seen at 3 months was still present and more pronounced at 6 months (type I: +17%, p = 0.04; type IIx: -65%, p = 0.032). The capillary fiber density was reduced at 3 months (type I: -43%, NS; type II: -44%, p = 0.0320) but normalized at 6 months. There was a non-significant increase in SC/100 fibers at 3 months (+75%, NS) and 6 months (+40%, NS) compared with the baseline. These preliminary data suggest that BoNT-A induced alterations in the MG of children with CP, which were still present 6 months after BoNT-A injection but with signs of muscle recovery.

Longitudinal Assessment of Facial Hyperhidrosis Management: Evaluating the Utility and Quality of Life Improvements following Botulinum Toxin Injection

Facial hyperhidrosis is a debilitating condition that can severely impact the quality of life. This study aimed to assess the long-term utility of Botulinum toxin type A therapy (BTA) for facial hyperhidrosis and its impact on quality of life over a one-year period. Conducted at the Pius Brinzeu Clinical Emergency Hospital in Timisoara, Romania, this longitudinal observational study involved 77 adult patients with primary facial hyperhidrosis. Participants received two sessions of Botulinum toxin injections (50 U IncoBTX-A each) and were evaluated at baseline, 6 months, and 12 months using the Hyperhidrosis Disease Severity Scale (HDSS), WHOQOL-BREF, Dermatology Life Quality Index (DLQI), and a bespoke survey. The study demonstrated significant reductions in HDSS scores from 3.6 ± 0.5 to 1.2 ± 0.8 post-treatment, sustained at 1.3 ± 0.6 at 12 months (p-value < 0.001). DLQI scores markedly decreased from 24.8 ± 4.2 to 6.2 ± 2.1 post-treatment, stabilizing at 6.5 ± 2.5 at 12 months (p-value < 0.001). Sweat production significantly dropped from 0.75 g ± 0.15 to 0.18 g ± 0.07 per 15 min (p-value < 0.001). WHOQOL-BREF scores improved notably in the mental domain from 66.7 ± 6.1 to 70.8 ± 5.2 at 12 months (p-value < 0.001), with physical and social domains also showing significant improvements. Correlation analysis revealed strong negative correlations between DLQI total score and HDSS (rho = -0.72, p-value < 0.001) and sweat production (rho = -0.68, p-value < 0.001). Regression analysis indicated significant predictors for DLQI total score, including HDSS (B Coefficient = -3.8, p-value < 0.001) and sweat production (B Coefficient = -2.2, p-value < 0.001). BTA therapy significantly improved the quality of life in facial hyperhidrosis patients, with lasting effects on symptom severity, sweat production, and quality of life domains. The correlation and regression analyses further substantiated the treatment's impact on both physical and psychological aspects. These findings advocate Botulinum toxin as a viable long-term treatment for facial hyperhidrosis.

Basis of movement control in dystonia and why botulinum toxin should influence it?

Dystonia is a network disorder involving multiple brain regions, such as the motor cortex, sensory cortex, basal ganglia, and cerebellum. Botulinum toxin (BoNT) is the first-line therapy for treating focal dystonia and is a potent molecule that blocks the release of acetylcholine at the peripheral neuromuscular junction. However, the clinical benefits of BoNT are not solely related to peripheral muscle relaxation or modulation of afferent input from the muscle spindle. An increasing body of evidence, albeit in smaller cohorts, has shown that BoNT leads to distant modulation of the pathological brain substrates implicated in dystonia. A single treatment session of BoNT has been observed to reduce excessive motor excitability and improve sensory processing. Furthermore, owing to plasticity effects that are induced by botulinum, neural reorganization of pathological networks occurs, presumably leading to defective motor programs of dystonia replaced with normal movement patterns. However, longitudinal studies investigating the effects of multiple treatment sessions in large, well-characterized homogenous cohorts of dystonia will provide further compelling evidence supporting central botulinum mechanisms.

Exploring the Central Mechanisms of Botulinum Toxin in Parkinson's Disease: A Systematic Review from Animal Models to Human Evidence

Botulinum toxin (BoNT) is an effective and safe therapy for the symptomatic treatment of several neurological disturbances. An important line of research has provided numerous pieces of evidence about the mechanisms of action of BoNT in the central nervous system, especially in the context of dystonia and spasticity. However, only a few studies focused on the possible central effects of BoNT in Parkinson's disease (PD). We performed a systematic review to describe and discuss the evidence from studies focused on possible central effects of BoNT in PD animal models and PD patients. To this aim, a literature search in PubMed and SCOPUS was performed in May 2023. The records were screened according to title and abstract by two independent reviewers and relevant articles were selected for full-text review. Most of the papers highlighted by our review report that the intrastriatal administration of BoNT, through local anticholinergic action and the remodulation of striatal compensatory mechanisms secondary to dopaminergic denervation, induces an improvement in motor and non-motor symptoms in the absence of neuronal loss in animal models of PD. In human subjects, the data are scarce: a single neurophysiological study in tremulous PD patients found that the change in tremor severity after peripheral BoNT administration was associated with improved sensory-motor integration and intracortical inhibition measures. Further clinical, neurophysiological, and neuroimaging studies are necessary to clarify the possible central effects of BoNT in PD.

Botulinum toxin A dissolving microneedles for hyperhidrosis treatment: design, formulation and in vivo evaluation

Multiple periodic injections of botulinum toxin A (BTX-A) are the standard treatment of hyperhidrosis which causes excessive sweating. However, BTX-A injections can create problems, including incorrect and painful injections, the risk of drug entry into the bloodstream, the need for medical expertise, and waste disposal problems. New drug delivery systems can substantially reduce these problems. Transdermal delivery is an effective alternative to conventional BTX-A injections. However, BTX-A's large molecular size and susceptibility to degradation complicate transdermal delivery. Dissolving microneedle patches (DMNPs) encapsulated with BTX-A (BTX-A/DMNPs) are a promising solution that can penetrate the dermis painlessly and provide localized translocation of BTX-A. In this study, using high-precision 3D laser lithography and subsequent molding, DMNPs were prepared based on a combination of biocompatible polyvinylpyrrolidone and hyaluronic acid polymers to deliver BTX-A with ultra-sharp needle tips of 1.5 ± 0.5 µm. Mechanical, morphological and histological assessments of the prepared DMNPs were performed to optimize their physicochemical properties. Furthermore, the BTX-A release and diffusion kinetics across the skin layers were investigated. A COMSOL simulation was conducted to study the diffusion process. The primary stability analysis reported significant stability for three months. Finally, the functionality of the BTX-A/DMNPs for the suppression of sweat glands was confirmed on the hyperhidrosis mouse footpad, which drastically reduced sweat gland activity. The results demonstrate that these engineered DMNPs can be an effective, painless, inexpensive alternative to hypodermic injections when treating hyperhidrosis.

Pathogenicity and virulence of Clostridium botulinum

Clostridium botulinum, a polyphyletic Gram-positive taxon of bacteria, is classified purely by their ability to produce botulinum neurotoxin (BoNT). BoNT is the primary virulence factor and the causative agent of botulism. A potentially fatal disease, botulism is classically characterized by a symmetrical descending flaccid paralysis, which is left untreated can lead to respiratory failure and death. Botulism cases are classified into three main forms dependent on the nature of intoxication; foodborne, wound and infant. The BoNT, regarded as the most potent biological substance known, is a zinc metalloprotease that specifically cleaves SNARE proteins at neuromuscular junctions, preventing exocytosis of neurotransmitters, leading to muscle paralysis. The BoNT is now used to treat numerous medical conditions caused by overactive or spastic muscles and is extensively used in the cosmetic industry due to its high specificity and the exceedingly small doses needed to exert long-lasting pharmacological effects. Additionally, the ability to form endospores is critical to the pathogenicity of the bacteria. Disease transmission is often facilitated via the metabolically dormant spores that are highly resistant to environment stresses, allowing persistence in the environment in unfavourable conditions. Infant and wound botulism infections are initiated upon germination of the spores into neurotoxin producing vegetative cells, whereas foodborne botulism is attributed to ingestion of preformed BoNT. C. botulinum is a saprophytic bacterium, thought to have evolved its potent neurotoxin to establish a source of nutrients by killing its host.

Skin Toxicities Associated with Botulin Toxin Injection for Aesthetic Procedures: Data from the European Spontaneous Reporting System

Botulinum toxin is a protein deriving from the bacteria Clostridium botulinum and it is widely used for the treatment of a variety of muscle hyperactivity syndromes and for cosmetic indications. Having a long-lasting effect, Botulinum toxin type A (BTA) is one of the most botulin toxin products used. Even if BTA has shown benefits in reducing the vertical lines between the eyebrows, Adverse Drug Reactions (ADRs) have been experienced as well, of which the most common ones are headache and drooping eyelids. In addition, since other local and systemic risks have been identified, a non-interventional post-authorization safety study (PASS) has been started. The aim of the present study was to report cases of skin toxicity associated with this drug, considering Individual Case Safety Reports (ICSRs) existing on the Eudravigilance website. Among 1464 ICSRs sent to the EV database, 718 ICSRs, including 5154 PTs, reported BTA as a suspected drug associated with cutaneous toxicity. The majority of patients experiencing BTA-induced skin toxicity were female (92.1%) belonging mostly to the age group of 18-64 years. The most serious criteria, when reported, were "Other Medically Important Condition" and "Caused/prolonged hospitalization", although the outcome was mainly reported as "Unknown". The most reported PTs, related to skin disorders, were: "Erythema", "Rash", "Pruritus", "Urticaria", "Swelling face", "Brow ptosis", "Eyelid ptosis", "Injection site pain", and "Angioedema". Considering that in most ICSRs, ADRs related to skin disorders were symptoms of hypersensitivity reactions which in some conditions could be life-threatening, further studies are required to better define the safety profile of BTA used for aesthetic procedures.

Tailored Indications for Different Neurotoxins

Background

Minimally invasive procedures have become increasingly popular because they require minimal downtime and are effective for achieving a more youthful appearance. All U.S. Food and Drug Administration-approved neurotoxins are indicated for achieving similar effects, even though they are different in regard to structure, manufacturing technique, and storage requirements. It is agreed upon that each neurotoxin is unique and therefore not interchangeable. The aim of the author is to provide an approach for choosing the optimal toxin in different indications regarding the area of treatment, the age and characteristics of the patient, potential risks, and ultimate goals.

Methods

As the country that the author practices carries onabotulinum (ONA), prabotulinum (PRA), and abobotulinum (ABO) toxin type-A, one of these three toxins was preferred for each category. ABO toxins were preferred in wide areas due to the broader action halo. Typical examples include hyperhidrosis treatment, wide forehead area, and calf slimming. In areas where very precise and targeted treatment is required, PRA and ONA toxins were preferred to limit potential side effects due to wider diffusion. First-time patients were typically treated with PRA toxins for a softer trial periods where as "repeat" patients were successfully treated with ABO toxins.

Results

No toxin is superior to the other in terms of producing effects. Yet, small differences in their properties can allow the plastic surgeon to cater to each patient's needs while yielding the most optimal results.

Conclusions

This study is meant to serve as a guideline for choosing the ideal toxin in different patient settings and indications.

"Pseudo"-Secondary Treatment Failure Explained via Disease Progression and Effective Botulinum Toxin Therapy: A Pilot Simulation Study

BACKGROUND

The objective of this study was to provide evidence from a simple simulation. In patients with focal dystonia, an initial good response to botulinum neurotoxin (BoNT) injections followed by a secondary worsening does not necessarily arise from an antibody-induced secondary treatment failure (NAB-STF), but may stem from a "pseudo"-secondary treatment failure (PSEUDO-STF).

METHODS

The simulation of the outcome after BoNT long-term treatment was performed in four steps: 1. The effect of the first single BoNT injection (SI curve) was displayed as a 12-point graph, corresponding to the mean improvement from weeks 1 to 12. 2. The remaining severity of the dystonia during the nth injection cycle was calculated by subtracting the SI curve (weighted by the outcome after n - 1 cycles) from the outcome after week 12 of the (n - 1)th cycle. 3. A graph was chosen (the PRO curve), which represents the progression of the severity of the underlying disease during BoNT therapy. 4. The interaction between the outcome during the nth BoNT cycle and the PRO curve was determined.

RESULTS

When the long-term outcome after n cycles of BoNT injections (applied every 3 months) was simulated as an interactive process, subtracting the effect of the first cycle (weighted by the outcome after n - 1 cycles) and adding the progression of the disease, an initial good improvement followed by secondary worsening results. This long-term outcome depends on the steepness of the progression and the duration of action of the first injection cycle. We termed this response behavior a "pseudo"-secondary treatment failure, as it can be compensated via a dose increase.

CONCLUSION

A secondary worsening following an initial good response in BoNT therapy of focal dystonia might not necessarily indicate neutralizing antibody induction but could stem from a "PSEUDO"-STF (a combination of good response behavior and progression of the underlying disease). Thus, an adequate dose adaptation must be conducted before diagnosing a secondary treatment failure in the strict sense.

A look at the future-new BoNTs and delivery systems in development: What it could mean in the clinic

Despite the expanding clinical utility of botulinum neurotoxins, there remain problems to be solved for attaining the best outcome. The efficacy and safety need to be reconsidered for commercially available preparations all derived from subtype A1 or B1. Emerging new toxins include A2 or A6 subtypes or engineered toxins with less spread, more potency, longer durations of action, less antigenicity and better safety profile than currently used preparations. Non-toxic BoNTs with a few amino acid replacements of the light chain (LC) may have a role as a drug-delivery system if the toxicity is abolished entirely. At present, efficacy of these BoNTs in animal botulism was demonstrated.

Layer-Specific BTX-A Delivery to the Gastric Muscularis Achieves Effective Weight Control and Metabolic Improvement

The rising incidence of health-endangering obesity constantly calls for more effective treatments. Gastric intramural injection of botulinum neurotoxin A (BTX-A) as a new modality carries great promise yet inconsistent therapeutic efficacy. A layer-specific delivery strategy enabled by dissolving microneedles is hence pioneered to investigate the working site of BTX-A and the resulting therapeutic effects. The drug-loaded tips of the layer-specific gastric paralysis microneedles (LGP-MN) rapidly release and achieve uniform distribution of BTX-A within the designated gastric wall layers. In an obesity rat model, the LGP-MNs not only prove safer than conventional injection, but also demonstrate consistently better therapeutic effects with muscular layer delivery, including 16.23% weight loss (3.06-fold enhancement from conventional injection), 55.20% slower gastric emptying rate, improved liver steatosis, lowered blood lipids, and healthier gut microbiota. Further hormonal study reveals that the elevated production of stomach-derived glucagon-like peptide-1 due to the muscularis-targeting LGP-MN treatment is an important contributor to its unique glucose tolerance-improving effect. This study provides clear indication of the gastric muscularis as the most favorable working site of BTX-A for weight loss and metabolic improvement purposes, and meanwhile suggests that the LGP-MNs could serve as a novel clinical approach to treat obesity and metabolic syndromes.

Bruxism and Botulinum Injection: Challenges and Insights

Botulinum toxin (BTA) is a bacterial-derived extract that can inhibit muscle contraction, acting directly on the absorption of acetylcholine. Thanks to this property, botulinum has been used in aesthetic and general medicine for several years. Nowadays, the use of botulinum toxin is being deepened to address the problem of bruxism. In this scoping review, the results of the studies in the literature of the last 10 years were analyzed. Indeed, 12 reports (found on PubMed, Web of Science, and Scopus, entering the keywords "BRUXISM" and "BOTULINUM TOXIN") were deemed eligible for inclusion in this review. In the studies reviewed, BTA was injected into different muscle groups: masseters, masseter and temporalis or masseter, temporalis, and medial pterygoid. Botulinum toxin injection is a viable therapeutic solution, especially in patients with poor compliance or without improvement in conventional treatment.

Botulinum toxin in the management of parkinsonian disorders

Many studies have shown that botulinum toxin (BoNT) can be an option to treat motor and non-motor symptoms in Parkinson's disease (PD) and parkinsonian syndromes. The advantages of BoNT compared to oral medications include localized action and low incidence of systemic side effects, which is important in treating neurodegenerative disease. Motor symptoms that can be treated with BoNT include blepharospasm, apraxia of eyelid opening, tremor, cervical dystonia and limb dystonia. Other indications with less evidence include camptocormia, freezing of gait and dyskinesia. Non-motor symptoms that may improve with BoNT include sialorrhea, pain, overreactive bladder, dysphagia and constipation. However, the current evidence for use of BoNT in parkinsonism is mostly based on open-label studies and there are few randomized, controlled trials. BoNT can be a valuable tool to treat certain symptoms of PD and parkinsonian syndromes to improve the patient's quality of life. However, many of the uses are not supported by high quality studies and further studies are needed to provide further evidence of efficacy, define the optimal injection protocols such as doses and muscle selection.

How does botulinum toxin really work?

Over the past 30 years, Botulinum toxin (BoNT) has emerged as an effective and safe therapeutic tool for a number of neurological conditions, including dystonia. To date, the exact mechanism of action of BoNT in dystonia is not fully understood. Although it is well known that BoNT mainly acts on the neuromuscular junction, a growing body of evidence suggests that the therapeutic effect of BoNT in dystonia may also depend on its ability to modulate peripheral sensory feedback from muscle spindles. Animal models also suggest a retrograde and anterograde BoNT transportation from the site of injection to central nervous system structures. In humans, however, BoNT central effects seem to depend on the modulation of afferent input rather than on BoNT transportation. In this chapter, we aimed to report and discuss research evidence providing information on the possible mechanisms of action of BoNT in relation to treatment of dystonia.

Trends in Botulinum Toxin Use among Patients with Multiple Sclerosis: A Population-Based Study

There are limited real-world data on the use of botulinum toxin type A (BoNT-A) in patients with multiple sclerosis (MS). Accordingly, this nationwide, population-based, retrospective cohort study aimed to describe BoNT-A treatment trends in patients with MS between 2014 and 2020 in France. This study extracted data from the French National Hospital Discharge Database (Programme de Médicalisation des Systèmes d'Information, PMSI) covering the entire French population. Among 105,206 patients coded with MS, we identified those who received ≥1 BoNT-A injection, administered within striated muscle for MS-related spasticity and/or within the detrusor smooth muscle for neurogenic detrusor overactivity (NDO). A total of 8427 patients (8.0%) received BoNT-A injections for spasticity, 52.9% of whom received ≥3 BoNT-A injections with 61.9% of the repeated injections administered every 3 to 6 months. A total of 2912 patients (2.8%) received BoNT-A injections for NDO, with a mean of 4.7 injections per patient. Most repeated BoNT-A injections within the detrusor smooth muscle (60.0%) were administered every 5 to 8 months. There were 585 patients (0.6%) who received both BoNT-A injections within striated muscle and the detrusor smooth muscle. Overall, our study highlights a broad range of BoNT-A treatment practices between 2014 and 2020 in patients with MS.

Is there a role for botulinum toxin A in the emergency setting for delayed abdominal wall closure in the management of the open abdomen? A systematic review

INTRODUCTION

Emergency laparotomy for either trauma or non-trauma indications is common and management is varied. Use of the open abdomen technique allowing for planned re-look is an option; however, performing delayed definitive fascial closure (DFC) following this can be a challenge. The use of botulinum toxin-A (BTX) infiltration into the lateral abdominal wall has been well documented within the elective setting; its use within the emergency setting is undecided. This systematic review assesses the efficacy and safety of BTX injection into the lateral abdominal wall muscles in the emergency setting. The primary outcome is DFC rate.

METHODS

Systematic review was performed according to the PROSPERO registered protocol (CRD42020205130). Papers were dual screened for eligibility, and included if they met pre-stated criteria where the primary outcome was DFC. Articles reporting fewer than five cases were excluded. Bias was assessed using the Cochrane Risk of Bias and Joanna Brigg's appraisal tools.

FINDINGS

Fourteen studies were screened for eligibility, twelve full texts were reviewed and two studies were included. Both studies showed evidence of bias due to confounding factors and lack of reporting. Both studies suggested significantly higher rates of DFC than reported in the literature against standard technique (90.7% vs 66%); however, these data are difficult to interpret due to strict study inclusion criteria or lack of a control population.

CONCLUSION

The use of BTX is deemed safe and its effects in the emergency situation may have great potential. Unfortunately, to date, there is insufficient evidence to facilitate opinion.

Xeomin®, a Commercial Formulation of Botulinum Neurotoxin Type A, Promotes Regeneration in a Preclinical Model of Spinal Cord Injury

Xeomin® is a commercial formulation of botulinum neurotoxin type A (BoNT/A) clinically authorized for treating neurological disorders, such as blepharospasm, cervical dystonia, limb spasticity, and sialorrhea. We have previously demonstrated that spinal injection of laboratory purified 150 kDa BoNT/A in paraplegic mice, after undergoing traumatic spinal cord injury (SCI), was able to reduce excitotoxic phenomena, glial scar, inflammation, and the development of neuropathic pain and facilitate regeneration and motor recovery. In the present study, as proof of concept in view of a possible clinical application, we studied the efficacy of Xeomin® in the same preclinical SCI model in which we highlighted the positive effects of lab-purified BoNT/A. Data comparison shows that Xeomin® induces similar pharmacological and therapeutic effects, albeit with less efficacy, to lab-purified BoNT/A. This difference, which can be improved by adjusting the dose, can be attributable to the different formulation and pharmacodynamics. Although the mechanism by which Xeomin® and laboratory purified BoNT/A induce functional improvement in paraplegic mice is still far from being understood, these results open a possible new scenario in treatment of SCI and are a stimulus for further research.

Dystonias: Clinical Recognition and the Role of Additional Diagnostic Testing

Dystonia is the third most common movement disorder, characterized by abnormal, frequently twisting postures related to co-contraction of agonist and antagonist muscles. Diagnosis is challenging. We provide a comprehensive appraisal of the epidemiology and an approach to the phenomenology and classification of dystonia, based on the clinical characteristics and underlying etiology of dystonia syndromes. We discuss the features of common idiopathic and genetic forms of dystonia, diagnostic challenges, and dystonia mimics. Appropriate workup is based on the age of symptom onset, rate of progression, whether dystonia is isolated or combined with another movement disorder or complex neurological and other organ system eatures. Based on these features, we discuss when imaging and genetic should be considered. We discuss the multidisciplinary treatment of dystonia, including rehabilitation and treatment principles according to the etiology, including when pathogenesis-direct treatment is available, oral pharmacological therapy, chemodenervation with botulinum toxin injections, deep brain stimulation and other surgical therapies, and future directions.

Biological and Immunological Characterization of a Functional L-HN Derivative of Botulinum Neurotoxin Serotype F

Botulinum neurotoxins (BoNTs) can cause nerve paralysis syndrome in mammals and other vertebrates. BoNTs are the most toxic biotoxins known and are classified as Class A biological warfare agents. BoNTs are mainly divided into seven serotypes A-G and new neurotoxins BoNT/H and BoNT/X, which have similar functions. BoNT proteins are 150 kDa polypeptide consisting of two chains and three domains: the light chain (L, catalytic domain, 50 kDa) and the heavy chain (H, 100 kDa), which can be divided into an N-terminal membrane translocation domain (HN, 50 kDa) and a C-terminal receptor binding domain (Hc, 50 kDa). In current study, we explored the immunoprotective efficacy of each functional molecule of BoNT/F and the biological characteristics of the light chain-heavy N-terminal domain (FL-HN). The two structure forms of FL-HN (i.e., FL-HN-SC: single chain FL-HN and FL-HN-DC: di-chain FL-HN) were developed and identified. FL-HN-SC could cleave the vesicle associated membrane protein 2 (VAMP2) substrate protein in vitro as FL-HN-DC or FL. While only FL-HN-DC had neurotoxicity and could enter neuro-2a cells to cleave VAMP2. Our results showed that the FL-HN-SC had a better immune protection effect than the Hc of BoNT/F (FHc), which indicated that L-HN-SC, as an antigen, provided the strongest protective effects against BoNT/F among all the tested functional molecules. Further in-depth research on the different molecular forms of FL-HN suggested that there were some important antibody epitopes at the L-HN junction of BoNT/F. Thus, FL-HN-SC could be used as a subunit vaccine to replace the FHc subunit vaccine and/or toxoid vaccine, and to develop antibody immune molecules targeting L and HN domains rather than the FHc domain. FL-HN-DC could be used as a new functional molecule to evaluate and explore the structure and activity of toxin molecules. Further exploration of the biological activity and molecular mechanism of the functional FL-HN or BoNT/F is warranted.

Lateral Epicondylitis: Critical Analysis Review of Current Nonoperative Treatments

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Lateral epicondylitis (LE) or tennis elbow is a common cause of elbow pain in the general population, especially women in the fourth and fifth decades of life who participate in repetitive forceful movements involving the wrist and forearm.

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The pathogenesis of this overuse injury is believed to start from an overload event leading to a microtear in or near the origin of the extensor carpi radialis brevis that is subsequently prone to additional injury and structural weakness over time.

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Treatment of LE often begins with a wide variety of nonoperative modalities including rest, nonsteroidal anti-inflammatory drugs, bracing, and physical therapy. For recalcitrant symptoms, additional nonoperative therapies are implemented; however, there remains a lack of comparative efficacy between these adjunct treatments.

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In this article, we examine the available literature regarding nonoperative management of LE and provide supplementary insight into the effectiveness of current modalities.

Utility of botulinum toxin injection for post-operative pain management after conventional hemorrhoidectomy: a systematic review and meta-analysis of clinical trials

BACKGROUND

Botulinum Toxin (BTX) has been found to have anti-spasm and analgesic effects. The utility of BTX after conventional hemorrhoidectomy remains unclear. Thus, a systematic review and meta-analysis are required to find out its utility after conventional hemorrhoidectomy.

METHODS

Using specific keywords, we comprehensively go through the potential articles on PubMed, ClinicalTrials.gov, and Europe PMC sources until March 27^th, 2022. All published studies on botulinum toxin anal sphincter injection after conventional hemorrhoidectomy were collected. We were using Review Manager 5.4 software to conduct statistical analysis.

RESULTS

Five clinical trial studies with a total of 260 patients undergoing hemorrhoidectomy were included in the analysis Our pooled analysis revealed that BTX injection after hemorrhoidectomy was associated with lower VAS at 24 h post-operative [Mean Difference -1.35 (95% CI -1.90, -0.80), p < 0.00001, I² = 0%] and shorter time to return work [Mean Difference -8.94 days (95% CI -12.57, -5.30), p < 0.00001, I² = 0%]. However, BTX injection did not differ significantly from placebo in terms of time to first defecation (p = 0.22), fecal incontinence (p = 0.91) and urinary retention incidence (p = 0.18).

CONCLUSION

BTX sphincter injection may offer some benefit after conventional hemorrhoidectomy in reducing pain from the first day after the procedure and promoting wound healing without complication. Further randomized clinical trials are still needed to confirm the results of our study.

Cosmetic Treatment Using Botulinum Toxin in the Oral and Maxillofacial Area: A Narrative Review of Esthetic Techniques

Botulinum toxin (BoNT) is an anaerobic rod-shaped-neurotoxin produced by Clostridium botulinum, that has both therapeutic and lethal applications. BoNT injection is the most popular cosmetic procedure worldwide with various applications. Patients with dynamic wrinkles in areas such as the glabella, forehead, peri-orbital lines, nasal rhytides, and perioral rhytides are indicated. Excessive contraction of muscles or hyperactivity of specific muscles such as bulky masseters, cobble stone chins, gummy smiles, asymmetric smiles, and depressed mouth corners can achieve esthetic results by targeting the precise muscles. Patients with hypertrophic submandibular glands and parotid glands can also benefit esthetically. There are several FDA-approved BoNTs (obabotuli-numtoxinA, abobotulinumtoxinA, incobotulinumtoxinA, letibotulinumtoxinA, prabotulinumtox-inA, daxibotulinumtoxinA, rimbotulinumtoxinB) and novel BoNTs on the market. This paper is a narrative review of the consensus statements of expert practitioners and various literature on the injection points and techniques, highlighting both the Asian and Caucasian population separately. This paper can serve as a practical illustrative guide and reference for optimal, safe injection areas and effective doses for application of BoNT in the face and oral and maxillofacial area. The history of BoNT indications, contraindications, and complications, and the merits of ultrasonography (US)-assisted injections are also discussed.

Treatment Outcomes of Intravesical Botulinum Toxin A Injections on Patients with Interstitial Cystitis/Bladder Pain Syndrome

Botulinum toxin A (BoNT-A) is effective in reducing bladder hypersensitivity and increasing capacity through the effects of anti-inflammation in the bladder urothelium; however, studies on the treatment outcome of interstitial cystitis/bladder pain syndrome (IC/BPS) are lacking. We investigated the treatment outcome in IC/BPS patients receiving intravesical BoNT-A injections. This retrospective study included IC/BPS patients who had 100U BoNT-A intravesical injections in the past 20 years. The treatment outcomes at 6 months following the BoNT-A treatment were evaluated using the global response assessment (GRA) scale. The treatment outcomes according to the GRA scale include clinical symptoms, urodynamic parameters, cystoscopic characteristics, and urinary biomarkers, and it was these predictive factors for achieving satisfactory outcomes which were investigated. Among the 220 enrolled patients (180 women, 40 men) receiving BoNT-A injections, only 87 (40%) had significantly satisfactory treatment outcomes. The satisfactory group showed significantly larger voided volumes, and lower levels of both the urinary inflammatory protein MCP-1 and the oxidative stress biomarker 8-isoprostane in comparison to the unsatisfactory group. The IC severity and detrusor pressure are predictive factors of BoNT-A treatment outcomes. IC/BPS patients with less bladder inflammation showed satisfactory outcomes with intravesical BoNT-A injections. Patients with severe bladder inflammation might require more intravesical BoNT-A injections to achieve a satisfactory outcome.

The Use of Botulinum Toxin in the Management of Hidradenitis Suppurativa: A Systematic Review

Hidradenitis suppurativa (HS) is a chronic inflammatory skin condition characterized by suppurative infection, sinus tract, and abscess formation. International management guidelines are largely consensus-based. Botulinum toxin (BTX) has been widely used in the treatment of apocrine and eccrine gland disorders, such as hyperhidrosis, although the effectiveness of BTX in the treatment of HS remains unknown. The aim of this systematic review was to understand the published evidence of BTX safety and effectiveness in the management of HS.

METHODS

We conducted a PRISMA-compliant, prospectively registered (PROSPERO, CRD42021228732), systematic review. We devised bespoke search strategy and applied it to the Cochrane Central Register of Controlled Trials, Medline, Embase, and OpenGrey up until March 2022. We included all clinical studies that reported outcomes following BTX treatment in patients diagnosed with HS (both adult and pediatric).

RESULTS

A total of 4658 studies were identified, of which six met full inclusion criteria reporting data on 26 patients. The six identified studies included one randomized control trial, one case series, and four case studies. The one included randomized control trial demonstrated a significant reduction in the Dermatology Life Quality Index score at 3 months following treatment with BTX.

CONCLUSIONS

The effectiveness and safety of BTX in the treatment of HS remain unknown. This systematic review identified a paucity of high-quality clinical data. Evidence of treatment effectiveness is likely to come from registry-based cohort studies using established core outcome sets in the first instance.

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.

Botulinum Toxin, a Drug with Potential Interest for Dentists—An Introduction

The review is an introduction to medical, non-cosmetic treatments with botulinum neurotoxin (BoNT) in the orofacial region. It focuses on the current most common, best-documented and safest indications of interest for dentists in terms of dystonia and sialorrhea. These conditions are recommended to start with and suitable to gain better skill and experience with BoNT. The introduction also stresses the importance of correct diagnostics based on interdisciplinary cooperation, precise targeting of the injections, measurements of treatment effect, and control of the oral health with regard to side effects.

Do Bacteria Provide an Alternative to Cancer Treatment and What Role Does Lactic Acid Bacteria Play?

Cancer is one of the leading causes of mortality and morbidity worldwide. According to 2022 statistics from the World Health Organization (WHO), close to 10 million deaths have been reported in 2020 and it is estimated that the number of cancer cases world-wide could increase to 21.6 million by 2030. Breast, lung, thyroid, pancreatic, liver, prostate, bladder, kidney, pelvis, colon, and rectum cancers are the most prevalent. Each year, approximately 400,000 children develop cancer. Treatment between countries vary, but usually includes either surgery, radiotherapy, or chemotherapy. Modern treatments such as hormone-, immuno- and antibody-based therapies are becoming increasingly popular. Several recent reports have been published on toxins, antibiotics, bacteriocins, non-ribosomal peptides, polyketides, phenylpropanoids, phenylflavonoids, purine nucleosides, short chain fatty acids (SCFAs) and enzymes with anticancer properties. Most of these molecules target cancer cells in a selective manner, either directly or indirectly through specific pathways. This review discusses the role of bacteria, including lactic acid bacteria, and their metabolites in the treatment of cancer.

Comparison of Botulinum neurotoxin efficiency in dystonia associated with Parkinson's disease and atypical parkinsonism: a retrospective study with a self-reported improvement scale

Botulinum neurotoxin (BoNT) is a useful therapeutic option to treat dystonic manifestations. Data on its efficiency on dystonia associated with Parkinson's disease (PD) or atypical parkinsonism (AP) are scarce and no comparison of the efficiency of BoNT has been performed between these diseases and between the different localizations of dystonia in these pathologies. We retrospectively collected from patients' medical records the result of 611 BoNT injections in 63 dystonic parkinsonian patients (44 PD and 19 AP) using a self-reported clinical improvement scale and duration of effect. Using these data, we modeled the degree of improvement and its duration after BoNT treatment with a linear mixed model. This allowed us to assess the influence of clinical parameters on the reported treatment efficiency. On a scale from 0 to 100, patients with PD and AP, respectively, report a mean improvement of 69% and 55% after BoNT injection and it is similar regarding the different localizations of dystonia. Duration of effect is, however, longer in PD compared to AP (P = 0.023). Patients' demographic and clinical characteristics had no effect on the degree of improvement or duration of effect. Overall, our results support the use of BoNT in the various dystonic phenomena associated with degenerative parkinsonian syndromes. Shorter delays between injection sessions should be considered in AP compared to PD.Trial registration: This study was registered on Clinicaltrial.gov (NCT04948684).

Cell-Free Blood Cell Secretome (BCS) Counteracts Skin Aging: Multi-Center Prospective Regenerative Aesthetic Medicine Study Using Exokine®

Background

The “Inflammation Theory of Ageing” identifies pro-inflammatory cytokines and oxidative damage as one cause of cellular and mitochondrial deterioration and aging. Cell-free blood cell secretome (BCS) also known as autologous conditioned serum (ACS) has shown anti-inflammatory and regenerative mode of action in musculoskeletal disorders and radicular compression.

Aim

To confirm that BCS can improve signs of skin aging from a previous study in a multi-center setting.

Methods

Prospective, one-armed, multi-center interventional therapeutic study. Ninety-five women with skin firmness loss were treated with four intra-dermal injection sessions in both cheeks at 0, 2, 4 and 6 weeks. BCS was processed with Exokine® medical device according to manufacturer’s instructions. Primary endpoints were cutometric R0 and R3 at 12 and 24 weeks. GAIS, FACE-Q^TM, Patient Attractivity Self-Assessment and safety were evaluated.

Results

Mean skin firmness (R0) improved significantly from baseline 0.40 mm to 0.38 mm at week 12 and to 0.36 mm at week 24. Mean skin tiring (R3) improved significantly from baseline 0.45 mm to 0.42 mm at week 12 and to 0.40 at week 24. FACE-Q^TM “Satisfaction with Skin” significantly improved from baseline to weeks 12, 24 and 48. So did “Satisfaction with Facial Appearance” and “Psychological and Social Function”. “Satisfaction with Decision” and “Satisfaction with Outcome” were stable at week 24 and 48. At week 48 patients assessed their age 1.68 years younger vs Baseline. FACE-Q^TM aging appraisal improves from Baseline 52.94 to 65.23 at week 48. GAIS, by both physicians and patients, confirm improvement of skin.

Conclusion

For up to 48 weeks four intra-dermal injections with cell-free BCS increase facial skin firmness and resilience to tiring and patients’ satisfaction with their facial appearance and skin. Patients perceive their face as younger. BCS has the ability to sustainably rejuvenate facial skin safely.

Study Registration

Registration on German clinical trials register: DRKS00013014.

An Update on the Cosmetic Use of Botulinum Toxin: The Pattern of Practice among Korean Dermatologists

The efficacy and safety of botulinum toxin injection have made it a popular aesthetic procedure worldwide. A cross-sectional survey was performed in order to determine the pattern of type A botulinum toxin injections in cosmetic practice, for which an 18-item questionnaire was distributed to dermatologists. A total of 469 Korean board-certified dermatologists participated in the survey, with the following results: the main candidates for type A botulinum toxin injection were individuals in their 40–50 years (46.1%), followed by those in their 20–30 years (33.4%), and people over 60 years of age (20.5%). Overall, the upper face (the glabella, forehead, and crow’s line, in decreasing order) was the most favored area of injection (51%). In contrast, body contouring (i.e., shoulder, calf) and treatment for benign masseter hypertrophy were significantly more popular in the 20–30 years age group than their older counterparts. For wrinkle effacement, the most preferred dilution was 100 units/2.5 mL with isotonic sodium chloride injection (51.2%), and the most often used interval was six months (43.6%). About half (46.3%) of the dermatologists reported the experience of clinical cases which were suspicious of botulinum toxin resistance. Despite this, regarding the choice of the product, type A botulinum toxin products with greater cost-effectiveness were favored over products with a lower risk of antibody formation. Other than its cosmetic usage, botulinum toxin is applied for a variety of skin conditions. Further studies are suggested in order to identify the practice pattern of type A botulinum toxin for therapeutic uses in dermatology, such as hyperhidrosis and rosacea.

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.

Temporary Botulinum Immobilization of Residuum Muscles for Facilitation of the Initial Ingrowth of Skin to the Porous Skin and Bone Integrated Pylon in the Technology of Direct Skeletal Attachment: Large Animal Model

Enhancing the technology of bone-anchored limb prosthetics, we present a modified porcine model for developing an infection-free integration between the skin and a percutaneous bone implant. The deeply porous Skin and Bone Integrated Pylon (SBIP) presented an infection-free skin-implant interface both after implantation into the dorsum and after implantation into the residuum after below-knee amputation. However, deep ingrowth of skin into the porous cladding of the SBIP was achieved better in the dorsal procedure, while implantation to the residuum sometimes developed a stoma, probably due to the high mobility of the skin and soft tissues in the pig's thigh. Uncontrolled high skin mobility during the first week after implantation constituted a limitation for the porcine animal model, which we tried to address in the current study. As our previous studies showed that casting of the leg residuum did not sufficiently limit the skin's movement around the implant, we tested a modified protocol of the implantation, which included injection of botulinum toxin into the thigh muscles. During the course of the study, we identified proper botulinum toxin componentry, dosage, and the period after injections to achieve a maximal effect of immobilization of the muscles affecting skin movements. To verify the immobilization, we used kinetic data on the asymmetry of loading during gait with the Strideway System, Tekscan, Inc., Boston, MA, USA. We found that injections in the four muscles of the distal thigh of the left hind leg with MYOBLOC® (rimabotulinumtoxinB; 5,000 units/muscle) were sufficient to provide noticeable immobilization by the fourth week after the procedure. This conclusion was made based on the analysis of the dynamics of asymmetry in vertical ground reactions on the injected (left hind) and uninvolved (right hind) legs during gait over an instrumented walkway.

Video-Urodynamic Characteristics and Predictors of Switching from Botulinum Neurotoxin a Injection to Augmentation Enterocystoplasty in Spinal Cord Injury Patients

Botulinum neurotoxin type A (BoNT-A) injection and augmentation enterocystoplasty (AE) are alternative and effective management strategies for neurogenic detrusor overactivity (NDO) refractory to pharmacotherapy. A great majority of patients with spinal cord injury (SCI) may, however, prefer BoNT-A injections to AE, due to the less invasive characteristics. In this study we evaluated the influence of various video-urodynamic study (VUDS) parameters in SCI patients who continuously received repeat BoNT-A detrusor injections or switched to AE to improve their bladder conditions. We compared the changes in the urodynamic parameters before and after each mode of treatment. In this retrospective study, all SCI patients with refractory NDO who had received at least one BoNT-A injection were enrolled. VUDS was performed before and after both BoNT-A injection and AE. All of the urodynamic parameters of the storage and micturition-including the bladder capacity of every sensation, maximal flow rate (Qmax), post-voiding residual volume, detrusor pressure at Qmax, and bladder contractility index-were recorded. A total of 126 patients, including 46 women and 80 men, with a mean age of 41.8 ± 13.1 years, were recruited for this study. All of the patients receiving either BoNT-A injection or AE had a statistically significant increase of bladder capacity at every time-point during filling and a decrease in detrusor pressure at Qmax during voiding. Patients who switched from BoNT-A to AE had greater improvements in their urodynamic parameters when compared with those who continued with BoNT-A injections. Accordingly, SCI patients receiving BoNT-A injections but experiencing few improvements in their urodynamic parameters should consider switching to AE to achieve a better storage function and bladder capacity.

Editorial on the Special Issue "Botulinum Toxin for the Treatment of Neurological Disorders: Where We Are and Where We Need to Go"

Over the past 30 years, botulinum toxin (BoNT) has seen an ever-expanding use in disorders afflicting the nervous system [...].

Botulinum toxin in cancer therapy-current perspectives and limitations

Abstract

Different serotypes of botulinum toxins (BoNTs) act upon different types of SNARE proteins. This property is used in aesthetic medicine to treat certain eye disorders such as crossed eyes (strabismus) and uncontrolled blinking (blepharospasm), to treat muscle spasms or movement disorders, and, for the two last decades, more and more often, to provide support in cancer therapy, especially so as to obtain analgesic effects upon spastic conditions. The limited literature data also suggests that the addition of BoNTs to the culture of cancer cell lines reduces cell growth, and mitotic activity, and promotes their apoptosis. BoNTs have several advantages that can be emphasized: BoNTs act on both perfusion and oxygenation; moreover, BoNTs are considered to be safe and free of systemic side effects upon administration. Recently, advances in molecular biology techniques have allowed a wide variety of novel BoNT constructs with alternative functions. These constructs could be assessed as potential new classes of anti-cancer drugs. This creates new potential perspectives in the wider use of non-toxic modified BoNT constructs in cancer therapy. In the light of the mentioned premises and existing literature reports, the aim of this review is to summarize current data and reports considering BoNT use in cancer therapy.

Key points

•Botulinum toxin (BoNTs) may be useful in cancer treatment.

•Botulinum toxin can serve as an analgesic after cancer radiotherapy.

•Botulinum toxin has the ability to inhibit tumor growth and promote apoptosis of neoplastic cells.

Screening of a Focused Ubiquitin-Proteasome Pathway Inhibitor Library Identifies Small Molecules as Novel Modulators of Botulinum Neurotoxin Type A Toxicity

Botulinum neurotoxins (BoNTs) are known as the most potent bacterial toxins, which can cause potentially deadly disease botulism. BoNT Serotype A (BoNT/A) is the most studied serotype as it is responsible for most human botulism cases, and its formulations are extensively utilized in clinics for therapeutic and cosmetic applications. BoNT/A has the longest-lasting effect in neurons compared to other serotypes, and there has been high interest in understanding how BoNT/A manages to escape protein degradation machinery in neurons for months. Recent work demonstrated that an E3 ligase, HECTD2, leads to efficient ubiquitination of the BoNT/A Light Chain (A/LC); however, the dominant activity of a deubiquitinase (DUB), VCIP135, inhibits the degradation of the enzymatic component. Another DUB, USP9X, was also identified as a potential indirect contributor to A/LC degradation. In this study, we screened a focused ubiquitin-proteasome pathway inhibitor library, including VCIP135 and USP9X inhibitors, and identified ten potential lead compounds affecting BoNT/A mediated SNAP-25 cleavage in neurons in pre-intoxication conditions. We then tested the dose-dependent effects of the compounds and their potential toxic effects in cells. A subset of the lead compounds demonstrated efficacy on the stability and ubiquitination of A/LC in cells. Three of the compounds, WP1130 (degrasyn), PR-619, and Celastrol, further demonstrated efficacy against BoNT/A holotoxin in an in vitro post-intoxication model. Excitingly, PR-619 and WP1130 are known inhibitors of VCIP135 and USP9X, respectively. Modulation of BoNT turnover in cells by small molecules can potentially lead to the development of effective countermeasures against botulism.

High-Dose Neuromodulators: A Roundtable on Making Sense of the Data in Real-World Clinical Practice

BACKGROUND

For aesthetic treatment with botulinum neurotoxin type A (BoNTA), interest in maximizing treatment duration and efficacy has prompted study of doses higher than those used in registration studies. As data emerge, it is important that physicians understand how to apply study findings to their own practice so that patient demand is satisfied.

OBJECTIVES

To bring together leading experts in neuromodulators for a roundtable discussion on the implications of high-dose BoNTA studies for patient care.

METHODS

The authors reviewed and discussed recent data from high-dose BoNTA studies for abobotulinum toxin A, incobotulinum toxin A, and Oonobotulinumtoxin A.

RESULTS

Discussion focused on the challenges of data interpretation and extrapolation of study findings for real-world patient care. The authors participated in a candid discussion of whether the observed improvements in treatment duration and patient satisfaction warrant treatment with high-dose regimens delivered as high-concentration injections. Safety was also discussed, as well as economic considerations for both practices and patients. Of note, for BoNTA products, the registration dose, when administered in a smaller total volume, appears to give rise to more durable results than those observed in pivotal trials, implicating product concentration as an important consideration. Importantly, at higher doses, extended duration of effect does not appear to be at the expense of natural-looking results.

CONCLUSIONS

While the authors provide considerations for the development of individual clinical practice, there is no one-size-fits-all recommendation. It may be that "high-dose" BoNTA is in reality the optimal dose; however, important economic considerations may prevent rapid uptake for all patients.