Botulinum toxin in clinical practice

Comparison of the efficacy of occlusal splint and botulinum toxin therapies in patients with temporomandibular disorders with sleep bruxism

PURPOSE

This study aims to evaluate the efficacy of occlusal splint and botulinum toxin (BTX) therapies for improving the pain scores and mouth opening in patients with temporomandibular disorders (TMD) with sleep bruxism (SB).

MATERIALS AND METHODS

A retrospective cohort study was conducted based on clinical record reviews of patients with TMD symptoms (e.g., temporomandibular joint [TMJ] pain, masticatory muscle pain, TMJ internal derangements, joint sounds, and limited mouth opening) and SB. The patients were divided into two groups: occlusal splint group and BTX group. Maximum unassisted mouth opening (MMO) and pain score on a visual analogue scale (VAS) before treatment and at 1‑, 3‑, and 6‑month follow-up were analyzed to evaluate the clinical outcomes.

RESULTS

A total of 60 patients (49 women and 11 men, mean age 34.63 ± 11.85 years) were enrolled. Each group had 30 patients. The comparisons of the groups at 1 and 3 months after treatment indicated that the BTX group had higher MMO values (P = 0.013 and 0.034, respectively) and lower VAS scores than the occlusal splint group (P = 0.000 and 0.001, respectively). No difference between the two groups was observed 6 months after treatment (P > 0.05).

CONCLUSIONS

Both occlusal splint and BTX treatment methods were successful in treating TMD with SB. BTX provided patients with rapid relief in the early period; therefore, BTX can be recommended as a primary treatment option in patients with greater pain.

Intragastric Botulinum Toxin Injection and Botulism: An Alarm for Clinicians

Clostridium botulinum produces the most potent bacterial toxin, botulinum toxin A (BTXA), which has various therapeutic and cosmetic indications. Intragastric BTXA injection is a new obesity treatment method that was argued to be safe due to the inactivation of BTXA through the liver or metabolization within the gastric wall. However, a 36-year-old woman was admitted to the intensive care unit (ICU) due to developing botulism as a result of an intragastric injection of BTXA. The diplopia, headaches, ptosis, decreased muscle force, and respiratory distress two days after injection were her first chief complaints, and also, she experienced significant dysphagia, hoarse voice, thick tongue, constipation, hyposmia, and hypogeusia after two weeks. This case report highlights the necessity for physicians to have sufficient information about this method and consider possible life-threatening adverse effects including botulism.

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.

Early investigational agents for the treatment of benign prostatic hyperplasia'

INTRODUCTION

Benign prostatic hyperplasia (BPH), as a clinical entity that affects many people, has always been in the forefront of interest among researchers, pharmaceutical companies, and physicians. Patients with BPH exhibit a diverse range of symptoms, while current treatment options can occasionally cause adverse events. All the aforementioned have led to an increased demand for more effective treatment options.

AREAS COVERED

This review summarizes the outcomes of new medications used in a pre-clinical and clinical setting for the management of male lower urinary tract symptoms (LUTS)/BPH and provides information about ongoing trials and future directions in the management of this condition. More specifically, sheds light upon drug categories, such as reductase‑adrenoceptor antagonists, drugs interfering with the nitric oxide (NO)/cyclic guanosine monophosphate (GMP) signaling pathway, onabotulinumtoxinA, vitamin D3 (calcitriol) analogues, selective cannabinoid (CB) receptor agonists, talaporfin sodium, inhibitor of transforming growth factor beta 1 (TGF-β1), drugs targeting the hormonal control of the prostate, phytotherapy, and many more.

EXPERT OPINION

Clinical trials are being conducted on a number of new medications that may emerge as effective therapeutic alternatives in the coming years.

Analysis of Breast Milk Samples in Lactating Women After Undergoing Botulinum Toxin Injections for Facial Rejuvenation: A Pilot Study

Abstract Background: There are little data on the risk to a breastfeeding infant after facial botulinum toxin injections to the mother. Objective: To detect the presence of botulinum toxin in breast milk from lactating subjects treated with facial botulinum toxin injections, as measured by enzyme-linked immunosorbent assay (ELISA). Methods: For this pilot study, lactating women were injected with standardized facial botulinum toxin type A (BTXA) (range 40-92 U). Collected breast milk samples over 5 days were analyzed for the presence of botulinum toxin. Exclusion criteria included (1) lactating women still using their breast milk for their infant, (2) muscular disorders, (3) any medication that could interfere with neuromuscular function, (4) uncontrolled systemic disease, (5) pregnant, and (6) neuromodulator injection in the past 90 days. Results: Four lactating women were recruited. Eight samples had no BTXA detected, whereas 8 of the 16 total had detectible amounts, which were well below the reported lethal oral dose for an infant. Conclusion: Although the exclusion of lactating women from receiving cosmetic botulinum toxin injections is out of an abundance of caution to the theoretical risk to the infant, this study helps support the notion that facial botulinum toxin injections do not warrant an interruption in breastfeeding. Further studies with larger sample sizes are needed.

Prevention of component separation in complex abdominal wall surgery by Botox prehabilitation: a propensity-matched study

AIM

To facilitate midline fascial closure in complex abdominal wall surgery, component separation techniques (CST) are usually required. However, CST is associated with an enlarged morbidity. Prehabilitation could increase the compliance of the abdominal wall and thereby decrease the necessity of myofascial release. This can be accomplished by administration of botulinum toxin type A (BTA) in the lateral abdominal wall musculature. The aim of this study was to determine the effect of BTA on the subsequent necessity to perform CST in patients with complex abdominal wall hernias.

METHODS

Patients with a complex abdominal wall hernia, planned to undergo CST between July 2020 and November 2022 were included. Outcome of procedures with 300U of BTA 4 (2-6) weeks prior to surgery, were retrospectively analyzed by comparison with propensity matched subjects of an historical group. Hernia width difference was assessed by CT and operative details were included.

RESULTS

A total of 13 patients with a median hernia width of 12 cm (IQR 9-14, range 24) were prehabilitated with BTA between July 2020 and November 2022. A CST was planned for all, however not required in 6/13 patients (46%) to accomplish midline fascial closure. A mean elongation of lateral abdominal wall musculature of 4.01 cm was seen in patients not requiring CST. Compared to the propensity score matched control group, a 27% reduction (p = 0.08) in the need for CST was observed.

CONCLUSION

There is a tendency for decrease of necessity for CST by preoperatively administered BTA in patients with complex abdominal wall defects. Although small, as this study used propensity matched comparison, further exploration of BTA should be encouraged.

Collateral beauty in the damages: an overview of cosmetics and therapeutic applications of microbial proteases

Microbial proteases are enzymes secreted by a variety of microorganisms, including bacteria and fungi, and have attracted significant attention due to their versatile applications in the food and pharmaceutical industries. In addition, certain proteases have been used in the development of skin health products and cosmetics. This article provides a review of microbial proteases in terms of their classification, sources, properties, and applications. Moreover, different pharmacological and molecular investigations have been reviewed. Various biological activities of microbial proteases, such as Arazyme, collagenase, elastin, and Nattokinase, which are involved in the digestion of dietary proteins, as well as their potential anti-inflammatory, anti-cancer, antithrombotic, and immunomodulatory effects have been included. Furthermore, their ability to control infections and treat various disorders has been discussed. Finally, this review highlights the potential applications and future perspectives of microbial proteases in biotechnology and biomedicine, and proposes further studies to develop new perspectives for disease control and health-promoting strategies using microbial resources.

Intrasphincteric Botox injections in Hirschsprung's disease: indications and outcome in 64 procedures over a ten-year period

BACKGROUND

Intrasphincteric botulinum toxin (Botox) injection for symptomatic postoperative anal achalasia in Hirschsprung's disease (HSCR) has found wide application in the last twenty years. The aim of this study was to describe effectiveness and functional outcome of a series of patients treated over a 10-year period.

METHODS

All consecutive HSCR patients who received intrasphincteric Botox injections between January 2007 and December 2016 were included. Demographic data and clinical features were collected. A detailed questionnaire focusing on outcome in the medium and long-term was administered to all families.

RESULTS

In the study period 64 intrasphincteric Botox injections were performed in 31 patients. Completed questionnaires were returned by 27 out of 28 eligible patients (96%) reporting improvement or symptoms resolution in 16 (59%). The highest success rates were experienced by patients younger than 4, with long HSCR forms and with recurrent enterocolitis (75%, 100% and 100% of success rates, respectively). No major complications occurred. Minor complications were described by 7 patients (26%).

CONCLUSIONS

Intrasphincteric Botox injection proved to be feasible, safe and reasonably effective in children with HSCR and postoperative anal achalasia. Infants and toddlers with long HSCR forms and recurrent bouts of enterocolitis are those who would benefit most from this treatment.

TFOS Lifestyle: Impact of cosmetics on the ocular surface

In this report the use of eye cosmetic products and procedures and how this represents a lifestyle challenge that may exacerbate or promote the development of ocular surface and adnexal disease is discussed. Multiple aspects of eye cosmetics are addressed, including their history and market value, psychological and social impacts, possible problems associated with cosmetic ingredients, products, and procedures, and regulations for eye cosmetic use. In addition, a systematic review that critically appraises randomized controlled trial evidence concerning the ocular effects of eyelash growth products is included. The findings of this systematic review highlight the evidence gaps and indicate future directions for research to focus on ocular surface outcomes associated with eyelash growth products.

Improvement in health-related quality of life with Botulinum toxin A injection in acquired superior oblique palsy

Purpose

This study aimed to investigate the outcomes of Botulinum toxin A (BTA) injection into the inferior oblique (IO) muscle for the management of unilateral acute acquired superior oblique palsy (SOP) and to evaluate changes in health-related quality of life post-injection using the Adult Strabismus-20 (AS-20) questionnaire.

Methods

A prospective cohort study was performed in patients with unilateral acute acquired SOP who received BTA injections. Four units of BTA were injected into the ipsilateral IO muscle. Ocular examinations were performed pre-and post-injection, including alignment, ocular movement, and cyclotorsion deviation. The patients' AS-20 questionnaire scores were analyzed.

Results

A total of 21 patients with acute acquired SOP were included. The initial median vertical deviation was 5 PD (range 1-16), which was improved to 0 PD (range 0-10) at both 1 and 6 months post-injection (p < 0.001 and p < 0.001, respectively). The median torsional deviation was 7° (range 2-18) at baseline and resolved to 0 degrees (range -3-5) at the 1-month and 0° (range -2-7) at the 6-month follow-up (p < 0.001 and p < 0.001, respectively). There were significant increases in the overall score (OAS), psychosocial subscale score (PSS), and functional subscale score (FSS) from baseline values at both the 1-month (p < 0.001, p < 0.001, and p = 0.001, respectively) and 6-month follow-up (all p < 0.001).

Conclusion

Injecting BTA into the ipsilateral IO muscle successfully resolved vertical and torsional deviations and significantly improved quality-of-life scores. Our findings show that BTA treatment, as an early treatment for acute acquired SOP, can help patients by significantly improving their quality of life.

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.

Structural basis for botulinum neurotoxin E recognition of synaptic vesicle protein 2

Botulinum neurotoxin E (BoNT/E) is one of the major causes of human botulism and paradoxically also a promising therapeutic agent. Here we determined the co-crystal structures of the receptor-binding domain of BoNT/E (HCE) in complex with its neuronal receptor synaptic vesicle glycoprotein 2A (SV2A) and a nanobody that serves as a ganglioside surrogate. These structures reveal that the protein-protein interactions between HCE and SV2 provide the crucial location and specificity information for HCE to recognize SV2A and SV2B, but not the closely related SV2C. At the same time, HCE exploits a separated sialic acid-binding pocket to mediate recognition of an N-glycan of SV2. Structure-based mutagenesis and functional studies demonstrate that both the protein-protein and protein-glycan associations are essential for SV2A-mediated cell entry of BoNT/E and for its potent neurotoxicity. Our studies establish the structural basis to understand the receptor-specificity of BoNT/E and to engineer BoNT/E variants for new clinical applications.

Botulinum neurotoxin: A therapeutic powerhouse with broad clinical implications

ABSTRACT

Clostridium botulinum is a Gram-positive bacterium that produces one of the most deadly chemodenervating toxins in the world. To date, six distinct neurotoxins are available for prescription use in the United States. Decades of data across aesthetic therapeutic areas and therapeutic disease states support the safety and efficacy of C. botulinum, providing good symptom management and improved quality of life in appropriately chosen patients. Unfortunately, many clinicians are slow to progress patients to toxin therapy from more conservative measures, and others wrongly interchange the products despite characteristics unique to each. Commensurate with an improved understanding of the complex pharmacology and clinical implications of botulinum neurotoxins is the importance for clinicians to appropriately identify, educate, refer, and/or treat candidate patients. This article provides an overview of the history, mechanism of action, differentiation, indications, and uses for botulinum neurotoxins.

Efficacy and safety of long-term botulinum toxin treatment for acquired cervical dystonia: a 25-year follow-up

Botulinum toxin A (BoNT/A) is the first-line treatment for idiopathic cervical dystonia (ICD) and is widely used in the clinical setting. To date, scanty data are available on the effectiveness of BoNT in treating acquired cervical dystonia (ACD). Here we present a long-term follow-up of ACD patients treated with BoNT/A that focused on safety and efficacy. The study included subjects who had received at least six treatments of three commercially available BoNT/A drugs [abobotulinumtoxinA (A/Abo), incobotulinumtoxinA (A/Inco) and onabotulinumtoxinA (A/Ona)]. Safety and efficacy were assessed based on patients' self-reports regarding adverse effects (AE), duration of improvement of dystonia and/or pain relief. Global clinical improvement was measured on a six-point scale. 23 patients with ACD were administered 739 treatments (A/Abo in 235, A/Inco in 72, A/Ona in 432) with a mean number of treatments of 31 ± 20 (range 6-76) and duration of 10 ± 6 weeks (range 2-25). The mean dose was 737 ± 292 U for A/Abo, 138 ± 108 U for A/Inco and 158 ± 80 U for A/Ona. The average benefit duration was 89 ± 26 (A/Abo), 88 ± 30 days (A/Inco), and 99 ± 55 days (A/Ona) (p = 0.011); global clinical improvement for all sessions was 4 ± 1. ANOVA one-way analysis indicated that A/Ona had the best profile in terms of duration (p < 0.05), whereas A/Abo had the best pain relief effect (p = 0.002). Side effects were reported in 9% of treatments (67/739), with ten treatments (1%) complicated by two side effects. Most side effects were rated mild to moderate; severe side effects occurred following three treatments with the three different BoNT; two required medical intervention. No allergic reactions were reported. Even after 25 years of repeated treatments, all serotypes of BoNT demonstrate positive effects in treating ACD with long-lasting efficacy and safety.

Efficacy, Safety, and Accuracy of Intra-articular Therapies for Hand Osteoarthritis: Current Evidence

The lifetime risk of symptomatic hand osteoarthritis (OA) is 39.8%, with one in two women and one in four men developing the disease by age 85 years and no disease-modifying drug (DMOAD) available so far. Intra-articular (IA) therapy is one of the options commonly used for symptomatic alleviation of OA disease as it can circumvent systemic exposure and potential side effects of oral medications. The current narrative review focuses on the efficacy and safety profiles of the currently available IA agents in hand OA (thumb-base OA or interphalangeal OA) such as corticosteroids and hyaluronic acid (HA), as well as the efficacy and safety of IA investigational injectates in phase 2/3 clinical trials such as prolotherapy, platelet-rich plasma, stem cells, infliximab, interferon-? and botulinum toxin, based on the published randomized controlled trials on PubMed database. The limited published literature revealed the short-term symptomatic benefits of corticosteroids in interphalangeal OA while long-term data are lacking. Most of the short-term studies showed no significant difference between corticosteroids and hyaluronic acid in thumb-base OA, usually with a faster onset of pain relief in the corticosteroid group and a slower but greater (statistically insignificant) pain improvement in the HA group. The majority of studies in investigational agents were limited by small sample size, short-term follow-up, and presence of serious side effects. In addition, we reported higher accuracy rates of drug administrations under imaging guidance than landmark guidance (blind method), and then briefly describe challenges for the long-term efficacy and prospects of IA therapeutics.

Neurotoxins Acting at Synaptic Sites: A Brief Review on Mechanisms and Clinical Applications

Neurotoxins generally inhibit or promote the release of neurotransmitters or bind to receptors that are located in the pre- or post-synaptic membranes, thereby affecting physiological functions of synapses and affecting biological processes. With more and more research on the toxins of various origins, many neurotoxins are now widely used in clinical treatment and have demonstrated good therapeutic outcomes. This review summarizes the structural properties and potential pharmacological effects of neurotoxins acting on different components of the synapse, as well as their important clinical applications, thus could be a useful reference for researchers and clinicians in the study of neurotoxins.

Do randomised controlled trials evaluating functional outcomes following botulinum neurotoxin-A align with focal spasticity guidelines? A systematic review

PURPOSE

The impact of botulinum neurotoxin-A (BoNT-A) on functional outcomes when managing focal muscle spasticity remains unclear. It is possible that randomised controlled trial (RCT) design and/or reporting may be a contributing factor. The objective of this review was to determine the extent to which RCTs evaluating functional outcomes following BoNT-A align with focal spasticity guidelines.

MATERIALS AND METHODS

RCTs published from 2010 were included if they targeted focal spasticity, included BoNT-A, randomised a physical intervention to the upper/lower limb, or the primary outcome(s) related to the activity/participation domains of the International Classification of Functioning, Disability, and Health. Data extraction and quality appraisal using the Modified PEDro and Modified McMasters Tool were performed independently by two reviewers. General research practices were also extracted such as compliance with therapy reporting guidelines.

RESULTS

Fifty-two RCTs were eligible. Individualised goal setting was uncommon (25%). Six studies (11.5%) included multi-disciplinary management, and five (9.6%) included patient/caregiver education. Four studies (7.7%) measured outcomes beyond 6 months. The Median Modified PEDro score was 11/15.

CONCLUSIONS

Alignment with focal spasticity guidelines in RCTs was generally low. Our understanding of the impact of focal spasticity management on functional outcomes may be improved if RCT design aligned more closely with guideline recommendations.IMPLICATIONS FOR REHABILITATIONThe influence of BoNT-A on improved functional outcomes is yet to be determined.Individualised goal setting with a multi-disciplinary team is uncommon in an RCT design, despite it being a key guideline recommendation.Given the long-term nature of spasticity management, guidelines recommend short as well as long-term reviews following intervention however RCTs rarely assess beyond 6 months.

Current and emerging treatment options for premature ejaculation

Premature ejaculation (PE) is a prevalent male sexual dysfunction. Current standard treatment regimens include behavioural therapies, topical anaesthetics, dapoxetine and other selective serotonin reuptake inhibitors (SSRIs). Most of the pharmacotherapeutic options target neurotransmitters (such as serotonin and oxytocin) that have a role in the ejaculation mechanism. However, these treatments are mildly effective and only provide a temporary delay in the ejaculation latency time, and PE recurs when the treatment is stopped. Thus, a treatment for PE is urgently needed and research is ongoing to find the ideal PE therapy. The efficacy and safety of topical anaesthetics and SSRIs in delaying ejaculation have been confirmed in many well-designed controlled trials. Both preclinical and clinical studies on new-generation SSRIs are ongoing. Moreover, promising results came from clinical trials in which the efficacy of on-demand PE therapies targeting neurotransmitters other than serotonin, such as α1-adrenoceptor antagonists and oxytocin antagonists, was assessed. Surgical intervention and neuromodulation have been proposed as potential treatment options for PE; however, current PE guidelines do not recommend these treatments owing to safety concerns.

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.

Crystal Structures of the Clostridium botulinum Neurotoxin A6 Cell Binding Domain Alone and in Complex with GD1a Reveal Significant Conformational Flexibility

Clostridium botulinum neurotoxin A (BoNT/A) targets the soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex, by cleaving synaptosomal-associated protein of 25 kDa size (SNAP-25). Cleavage of SNAP-25 results in flaccid paralysis due to repression of synaptic transmission at the neuromuscular junction. This activity has been exploited to treat a range of diseases associated with hypersecretion of neurotransmitters, with formulations of BoNT/A commercially available as therapeutics. Generally, BoNT activity is facilitated by three essential domains within the molecule, the cell binding domain (H_C), the translocation domain (H_N), and the catalytic domain (LC). The H_C, which consists of an N-terminal (H_CN) and a C-terminal (H_CC) subdomain, is responsible for BoNT’s high target specificity where it forms a dual-receptor complex with synaptic vesicle protein 2 (SV2) and a ganglioside receptor on the surface of motor neurons. In this study, we have determined the crystal structure of botulinum neurotoxin A6 cell binding domain (H_C/A6) in complex with GD1a and describe the interactions involved in ganglioside binding. We also present a new crystal form of wild type H_C/A6 (crystal form II) where a large ‘hinge motion’ between the H_CN and H_CC subdomains is observed. These structures, along with a comparison to the previously determined wild type crystal structure of H_C/A6 (crystal form I), reveals the degree of conformational flexibility exhibited by H_C/A6.

Goal-Setting in Multiple Sclerosis-Related Spasticity Treated with Botulinum Toxin: The GASEPTOX Study

Spasticity is one of the most disabling symptoms in multiple sclerosis (MS). Botulinum toxin injection (BTI) is a first-line treatment for focal spasticity. There is a lack of evidence of a functional improvement following BTI in MS-related spasticity. To describe goal-setting for BTI in MS, and evaluate the degree of attainment, using goal attainment scaling (GAS) 4-to-6 weeks after injection session, a one-year multi-center retrospective observational study assessing goal-setting and achievement during BTI session in spastic patients with MS was set up. Following the GAS method, patients and their physicians set up to three goals and scored their achievement 4 to 6 weeks thereafter. Commonly used goals from three centers were combined into a standardized list and 125 single BTI sessions were analyzed. The most frequent goals regarded lower limb (LL) impairments (equinovarus foot, toe claw) or locomotion (stability, walking distance, clinging) and accounted for 89.1%, versus 10.9% for upper limb (UL), mostly for mild-to-moderate MS. Overall, goals were frequently achieved (85.77%) mainly when related to gait and mobility rather than hygiene and ease of care. This study gives an overview on the most frequent, relevant, and achievable goals to be set in real-life practice of BTI for spasticity management in MS.

Elucidation of critical pH-dependent structural changes in Botulinum Neurotoxin E

Botulinum Neurotoxins (BoNT) are the most potent toxins currently known. However, they also have therapeutic applications for an increasing number of motor related conditions due to their specificity, and low diffusion into the system. Although the start- and end- points for the BoNT mechanism of action are well-studied, a critical step remains poorly understood. It is theorised that BoNTs undergo a pH-triggered conformational shift, activating the neurotoxin by priming it to form a transmembrane (TM) channel. To test this hypothesis, we combined molecular dynamics (MD) simulations and small-angle x-ray scattering (SAXS), revealing a new conformation of serotype E (BoNT/E). This conformation was exclusively observed in simulations below pH 5.5, as determined by principal component analysis (PCA), and its theoretical SAXS profile matched an experimental SAXS profile obtained at pH 4. Additionally, a localised secondary structural change was observed in MD simulations below pH 5.5, in a region previously identified as instrumental for membrane insertion for serotype A (BoNT/A). These changes were found at a critical pH value for BoNTs in vivo, and may be relevant for their therapeutic use.

Comparative Pharmacodynamics of Three Different Botulinum Toxin Type A Preparations following Repeated Intramuscular Administration in Mice

Botulinum neurotoxin type A (BoNT/A) causes muscle paralysis by blocking cholinergic signaling at neuromuscular junctions and is widely used to temporarily correct spasticity-related disorders and deformities. The paralytic effects of BoNT/A are time-limited and require repeated injections at regular intervals to achieve long-term therapeutic benefits. Differences in the level and duration of effectivity among various BoNT/A products can be attributed to their unique manufacturing processes, formulation, and noninterchangeable potency units. Herein, we compared the pharmacodynamics of three BoNT/A formulations, i.e., Botox^® (onabotulinumtoxinA), Xeomin^® (incobotulinumtoxinA), and Coretox^®, following repeated intramuscular (IM) injections in mice. Three IM injections of BoNT/A formulations (12 U/kg per dose), 12-weeks apart, were administered at the right gastrocnemius. Local paresis and chemodenervation efficacy were evaluated over 36 weeks using the digit abduction score (DAS) and compound muscle action potential (CMAP), respectively. One week after administration, all three BoNT/A formulations induced peak DAS and maximal reduction of CMAP amplitudes. Among the three BoNT/A formulations, only Coretox^® afforded a significant increase in paretic effects and chemodenervation with a prolonged duration of action after repeated injections. These findings suggest that Coretox^® may offer a better overall therapeutic performance in clinical settings.

Discovering Biological Conflict Systems Through Genome Analysis: Evolutionary Principles and Biochemical Novelty

Biological replicators, from genes within a genome to whole organisms, are locked in conflicts. Comparative genomics has revealed a staggering diversity of molecular armaments and mechanisms regulating their deployment, collectively termed biological conflict systems. These encompass toxins used in inter- and intraspecific interactions, self/nonself discrimination, antiviral immune mechanisms, and counter-host effectors deployed by viruses and intragenomic selfish elements. These systems possess shared syntactical features in their organizational logic and a set of effectors targeting genetic information flow through the Central Dogma, certain membranes, and key molecules like NAD⁺. These principles can be exploited to discover new conflict systems through sensitive computational analyses. This has led to significant advances in our understanding of the biology of these systems and furnished new biotechnological reagents for genome editing, sequencing, and beyond. We discuss these advances using specific examples of toxins, restriction-modification, apoptosis, CRISPR/second messenger-regulated systems, and other enigmatic nucleic acid-targeting systems. Expected final online publication date for the Annual Review of Biomedical Data Science, Volume 5 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Pore Size-Dependent Stereoscopic Hydrogels Enhance the Therapeutic Efficiency of Botulinum Toxin for the Treatment of Nerve-Related Diseases

Botulinum toxin (BoNT) is a major neurotherapeutic protein that has been used at low doses for diverse pharmacological applications. However, the pleiotropic effect of BoNT depends on multiple periodic injections owing to its rapid elimination profile, short-term therapeutic effect, and high mortality rate when administered at high doses. In addition to low patient compliance, these drawbacks represent the significant challenges that limit the further clinical use of BoNT. This study developed a new hydrogel-based single dosage form of BoNT by employing a one-step cross-linking chemistry. Its controlled porous structures and composition facilitated uniform drug distribution inside the hydrogel and controllable release of BoNT mediated by slow diffusion. A single dose remained stable for at least 2.5 months and showed sustained effect for at least 20 weeks, meeting the requirements for a single-dose form of BoNT. Additionally, this dosage form was evaluated as safe from all aspects of toxicology. This delivery system resulted in a 100% survival rate after administering a BoNT dose of 30 units, while a dose of more than 5 units of naked BoNT caused a 100% mortality rate within a few days. Overall, this strategy could provide patients with the first single-dose treatment option of BoNT and improve their quality of life.

Immunogenicity of botulinum toxin

Botulinum toxin treatment is the most common non-surgical cosmetic treatment. Although there are many available treatments using botulinum toxin, their effects are temporary and repeated injections are required. These frequent injections can trigger an immunological response. In addition, botulinum toxin acts as an antigen in the body; thus, its effect disappears progressively due to this immunological reaction, which may cause treatment failure. Active botulinum toxin consists of a core neurotoxin and complexing proteins, the exact effects of which remain unclear. However, the complexing proteins are closely related to the immune response and the formation of neutralizing antibodies. Since neutralizing antibodies can lead to treatment failure, their formation should be prevented. Furthermore, various methods of detecting neutralizing antibodies have been used to predict treatment failure.

Botulinum Toxin Injection for Painful Adductor Pollicis Contracture after Thumb Carpometacarpal Resection Arthroplasty

Pollux adductus deformity is an accompanying symptom of thumb carpometacarpal osteoarthritis. We describe a case of a patient who presented with increased muscle tone of the adductor pollicis muscle and chronic pain in the thenar musculature, i.e., recurrence of an adduction deformity. The patient reported a symptom-free period of 5.5 years after having received resection-suspension-arthroplasty for stage IV thumb carpometacarpal osteoarthritis until spasmodic pain appeared. Due to the functional impairment of this condition, we administered therapy including 100 units of Botox^® (onabotulinumtoxinA, Allergan, Dublin, Ireland) injected with a fanning technique into the adductor pollicis muscle. Thus, we observed a substantial improvement in the patient-reported outcome measures as well as pain levels compared with initial values. The current case shows the pivotal role of the adductor pollicis muscle when patients report pain at the base of the thumb, which can cause considerable impairments despite the complication-free surgical treatment of thumb CMC OA.

Botulinum Toxin A Ameliorates Neuroinflammation in the MPTP and 6-OHDA-Induced Parkinson's Disease Models

Recently, increasing evidence suggests that neuroinflammation may be a critical factor in the development of Parkinson's disease (PD) in addition to the ratio of acetylcholine/dopamine because dopaminergic neurons are particularly vulnerable to inflammatory attack. In this study, we investigated whether botulinum neurotoxin A (BoNT-A) was effective for the treatment of PD through its anti-neuroinflammatory effects and the modulation of acetylcholine and dopamine release. We found that BoNT-A ameliorated MPTP and 6-OHDA-induced PD progression, reduced acetylcholine release, levels of IL-1β, IL-6 and TNF-α as well as GFAP expression, but enhanced dopamine release and tyrosine hydroxylase expression. These results indicated that BoNT-A had beneficial effects on MPTP or 6-OHDA-induced PD-like behavior impairments via its anti-neuroinflammation properties, recovering dopamine, and reducing acetylcholine release.

Oromandibular dystonia and temporomandibular disorders

BACKGROUND

The aim of this study was to characterize clinical features of patients with oromandibular dystonia (OMD) who had temporomandibular disorder (TMD) symptoms.

METHODS

A retrospective chart review of patients seeking treatment at a tertiary-level orofacial pain clinic from January 2015 through December 2020 was undertaken. The inclusionary criteria consisted of a diagnosis of OMD (International Classification of Diseases, Revision 10 code G24.4), which had been confirmed by a neurologist.

RESULTS

Eleven patients met the inclusion criteria. Focal dystonia and jaw deviation OMD were the most frequent diagnoses. A dental procedure was a triggering or aggravating factor in 36.4% of patients. All but 2 patients had a sensory trick, or tactile stimulus to a particular body part, and approximately one-half of the patients used an oral appliance as a sensory trick device. All but 1 patient had received a diagnosis of TMD, with myofascial pain of the masticatory muscles being the most prevalent diagnosis. Four patients had received a recommendation for orthodontic treatment. About one-half of the patients had undergone 1 or more invasive dental or maxillofacial surgical interventions to address their dystonia. Anxiety was the most common psychological comorbidity.

CONCLUSIONS

Because patients with OMD commonly experience TMD symptoms, they can receive a misdiagnosis of TMD while the OMD is overlooked.

PRACTICAL IMPLICATIONS

Owing to concomitant TMD symptoms, patients most often seek dental consultations and undergo treatments such as orthodontic interventions and temporomandibular joint surgeries. A dentist's competency in recognizing these patients can prevent unnecessary procedures and facilitate appropriate patient care.

Comparative Effectiveness of Injection Therapies for Hemiplegic Shoulder Pain in Stroke: A Systematic Review and Network Meta-Analysis

Hemiplegic shoulder pain (HSP) hampers post-stroke functional recovery and is not well managed with conservative treatments. This systematic review aimed to examine the various injection therapies for HSP and investigate their effectiveness at different time points. The protocol of this meta-analysis was registered on INPLASY with a registration number of INPLASY202180010. PubMed, EMBASE, and Scopus were searched from their inception to 4 August 2021 for the clinical studies investigating comparative effectiveness of different injection regimens for treating hemiplegic shoulder pain in patients with stroke. The primary outcome was the weighted mean difference (WMD) on the visual analog scale (VAS) of pain reduction in the fourth-week and between the fourth and twenty-fourth weeks. Ranking probabilities of the WMD for each treatment were obtained using simulations. Seventeen studies with 595 participants were included. The network meta-analysis showed that at the fourth-week, intra-muscular botulinum toxin (BoNT) injections and suprascapular nerve blocks (SSNB) were superior to a placebo, with WMDs of 1.55 (95% CI, 0.09 to 3.01) and 1.44 (95% CI, 0.07 to 2.80), respectively. SSNB possessed the highest probability (53.3%) and appeared to be the best treatment in the fourth-week, followed by intra-muscular BoNT injections (42.6%). Intramuscular BoNT injections were better than the placebo, with a WMD of 1.57 (95% CI, 0.30 to 2.84) between the 4th and 24th weeks. Intramuscular BoNT injections had the highest probability (79.8%) as the best treatment between the 4th and 24th weeks. SSNB was likely to rank first in relieving HSP at the fourth post-treatment week, whereas intra-muscular BoNT injections had the highest probability to achieve the best treatment effectiveness in the post-injection period between the fourth and twenty-fourth weeks. However, as some of the included studies used a non-randomized controlled design, more randomized controlled trials are needed in the future to validate and better understand the short- and long-term efficacy of different injection therapies for management of HSP.

Botulinum Toxin in the Surgical Treatment of Complex Abdominal Hernias: A Surgical Anatomy Approach, Current Evidence and Outcomes

BACKGROUND/AIM

Abdominal wall hernias represent a common problem in surgical practice. A significant proportion of them entails large defects, often difficult to primarily close without advanced techniques. Injection of botulinum toxin preoperatively at specific points targeting lateral abdominal wall musculature has been recently introduced as an adjunct in achieving primary fascia closure rates.

MATERIALS AND METHODS

A literature search was conducted investigating the role of botulinum toxin in abdominal wall reconstruction focusing on anatomic repair of hernia defects.

RESULTS

Injecting botulinum toxin preoperatively achieved chemical short-term paralysis of the lateral abdominal wall muscles, enabling a tension-free closure of the midline, which according to anatomic and clinical studies should be the goal of hernia repair. No significant complications from botulinum injections for complex hernias were reported.

CONCLUSION

Botulinum is a significant adjunct to complex abdominal wall reconstruction. Further studies are needed to standardize protocols and create more evidence.

A Comprehensive Review of Tic Disorders in Children

Tics are characterized by sudden, rapid, recurrent, nonrhythmic movement or vocalization, and are the most common movement disorders in children. Their onset is usually in childhood and tics often will diminish within one year. However, some of the tics can persist and cause various problems such as social embarrassment, physical discomfort, or emotional impairments, which could interfere with daily activities and school performance. Furthermore, tic disorders are frequently associated with comorbid neuropsychiatric symptoms, which can become more problematic than tic symptoms. Unfortunately, misunderstanding and misconceptions of tic disorders still exist among the general population. Understanding tic disorders and their comorbidities is important to deliver appropriate care to patients with tics. Several studies have been conducted to elucidate the clinical course, epidemiology, and pathophysiology of tics, but they are still not well understood. This article aims to provide an overview about tics and tic disorders, and recent findings on tic disorders including history, definition, diagnosis, epidemiology, etiology, diagnostic approach, comorbidities, treatment and management, and differential diagnosis.

Botulinum toxin type A versus anticholinergics for cervical dystonia

BACKGROUND

This is an update of a Cochrane Review first published in 2005. Cervical dystonia is the most common form of focal dystonia and is a highly disabling movement disorder, characterised by involuntary, usually painful, head posturing. Currently, botulinum toxin type A (BtA) is considered the first line therapy for this condition. Before BtA, anticholinergics were the most widely accepted treatment.

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus anticholinergic drugs in adults with cervical dystonia.

SEARCH METHODS

We searched the Cochrane Movement Disorders' Trials Register to June 2003, screened reference lists of articles and conference proceedings to September 2018, and searched CENTRAL, MEDLINE, and Embase, with no language restrictions, to July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised trials (RCTs) of BtA versus anticholinergic drugs in adults with cervical dystonia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records, selected included studies, extracted data using a paper pro forma, and evaluated the risk of bias and quality of the evidence. We resolved disagreements by consensus or by consulting a third review author. If enough data had been available, we were to perform meta-analyses using a random-effects model for the comparison of BtA versus anticholinergic drugs to estimate pooled effects and corresponding 95% confidence intervals (95% CI). The primary efficacy outcome was improvement in cervical dystonia-specific impairment. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We included one RCT of moderate overall risk of bias (as multiple domains were at unclear risk of bias), which included 66 BtA-naive participants with cervical dystonia. Two doses of BtA (Dysport; week 0 and 8; mean dose 262 to 292 U) were compared with daily trihexyphenidyl (up to 24 mg daily). The trial was sponsored by the BtA producer. BtA reduced cervical dystonia severity by an average of 2.5 points (95% CI 0.68 to 4.32) on the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) severity subscale 12 weeks after injection, compared to trihexyphenidyl. More participants reported adverse events in the trihexyphenidyl treatment group (76 events), compared with the BtA group (31 events); however, the difference in dropouts due to adverse events was inconclusive between groups. There was a decreased risk of dry mouth, and memory problems with BtA, but the differences were inconclusive between groups for the other reported side effects (blurred vision, dizziness, depression, fatigue, pain at injection site, dysphagia, and neck weakness).

AUTHORS' CONCLUSIONS

We found very low-certainty evidence that BtA is more effective, better tolerated, and safer than trihexyphenidyl. We found no information on a dose-response relationship with BtA, differences between BtA formulations or different anticholinergics, the utility of electromyography-guided injections, or the duration of treatment effect.

Scientific review of the aesthetic uses of botulinum toxin type A

Botulinum toxin type A (BoNT-A), onabotulinumtoxinA (Botox) was approved by the United States Food and Drug Administration for temporary improvement of glabellar lines in patients 65 years and younger in 2002, and has also been used widely for aesthetic purposes such as hyperhidrosis, body shape contouring, and other noninvasive facial procedures. BoNT-A inhibits presynaptic exocytosis of acetylcholine (ACh)-containing vesicles into the neuromuscular junction at cholinergic nerve endings of the peripheral nervous system, thereby paralyzing skeletal muscles. ACh is the most broadly used neurotransmitter in the somatic nervous system, preganglionic and postganglionic fibers of parasympathetic nerves, and preganglionic fibers or postganglionic sudomotor nerves of sympathetic nerves. The scientific basis for using BoNT-A in various cosmetic procedures is that its function goes beyond the dual role of muscle paralysis and neuromodulation by inhibiting the secretion of ACh. Although the major target organs for aesthetic procedures are facial expression muscles, skeletal body muscles, salivary glands, and sweat glands, which are innervated by the somatic or autonomic nerves of the peripheral cholinergic nerve system, few studies have attempted to directly explain the anatomy of the areas targeted for injection by addressing the neural physiology and rationale for specific aesthetic applications of BoNT-A therapy. In this article, we classify the various cosmetic uses of BoNT-A according to the relevant component of the peripheral nervous system, and describe scientific theories regarding the anatomy and physiology of the cholinergic nervous system. We also review critical physiological factors and conditions influencing the efficacy of BoNT-A for the rational aesthetic use of BoNT-A. We hope that this comprehensive review helps promote management policies to support long-term, safe, successful practice. Furthermore, based on this, we look forward to developing and expanding new advanced indications for the aesthetic use of BoNT-A in the future.

Comparative Pharmacodynamics Study of 3 Different Botulinum Toxin Type A Preparations in Mice

A new complexing protein-free botulinum toxin Type A (CBoNT) with the same mechanism of action as the botulinum toxin complex onabotulinumtoxinA (OBoNT) and complexing protein-free incobotulinumtoxinA (IBoNT) was recently developed.

The Efficacy of Dose Increments of Botulinum Toxin A in the Treatment of Childhood Esotropia

Background

Botulinum toxin is known to have a powerful chemodenervation effect, and it is a well-established alternative to incisional surgery for strabismus. This study aims to investigate the efficacy of dose increments of botulinum toxin A (BTA) for the treatment of specific ranges of angle deviation.

Methods

This was a prospective study that included patients presenting with esotropia to Dhahran Eye Specialist Hospital between 2016 and 2020, who were managed by a single surgeon. Botulinum toxin was given in different dosages (2.5, 5, 7.5, 10 international units (IU)) according to the size of deviation (11–19, 20–29, 30–39, and ≥40 prism diopters (PD)), respectively. A successful outcome was defined as deviation ≤10 PD in the last visit (a minimum of 6 months) following a single injection.

Results

A total of 56 patients with esotropia were included. The mean pre-treatment angle of deviation was 38.6 ± 2.5 PD. BTA injection in a dose of 2.5 IU for the 11–19 PD angle of deviation showed the highest rate of successful outcomes (75%). According to the type of esotropia, partially accommodative esotropia showed the best response to the use of dose increments (59%). The incidence of ptosis post-BTA injection was the least (37.5%) with the smallest dose (2.5 IU).

Conclusion

BTA usage in dose increments is safe, efficient, and might be more cost-effective with less incidence of BTA associated complications. Different esotropia diagnoses have different clinical responses. However, larger studies are necessary to better predict the outcome of using dose increments.

Effects of Prismatic Lenses on Lateral Axial Dystonia in Parkinson's Disease: A Pilot Study

OBJECTIVE: In Parkinson's disease (PD), postural abnormalities such as lateral axial dystonia (LAD) are relatively common. Evidence suggests that both peripheral and central mechanisms contribute to these postural abnormalities. We previously reported an improvement in LAD following the use of prisms in two PD patients. Here, we further investigate the effects of prismatic lenses in a case series of nine patients with PD and LAD. METHODS: Nine patients underwent an orthoptic evaluation and were provided with prismatic lenses. Patients were evaluated at baseline and after one and three months of permanent prismatic lens use and again re-evaluated one month after the discontinuation of prismatic lens use. RESULTS: We found a linear relationship between disease duration and LAD severity. Compared to basal measurements, we observed a slight improvement in LAD. Furthermore, we found a significant reduction in self-perceived back pain due to the use of prismatic lenses. There was no significant association between the individual effects of prismatic lenses in patients with PD and their baseline LAD or other clinical and demographic features (all P>0.05). CONCLUSION: The present pilot study provides novel data on the possible effectiveness of prismatic lenses for LAD treatment in PD patients.

Botulinum toxin type A therapy for blepharospasm

BACKGROUND

This is an update of a Cochrane Review first published in 2005. Blepharospasm is the second most common form of focal dystonia. It is a disabling disorder, characterised by chronic, intermittent or persistent, involuntary eyelid closure, due to spasmodic contractions of the orbicularis oculi muscles. Currently, botulinum toxin type A (BtA) is considered the first line of therapy for this condition.

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus placebo in people with blepharospasm.

SEARCH METHODS

We searched Cochrane Movement Disorders' Trials Register, CENTRAL, MEDLINE, Embase, reference lists of included articles, and conference proceedings. We ran all elements of the search, with no language restrictions, in July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with blepharospasm.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records, selected included studies, extracted data using a paper pro forma, and evaluated the risk of bias. We resolved disagreements by consensus, or by consulting a third review author. We performed meta-analyses using a random-effects model, for the comparison of BtA versus placebo, to estimate pooled effects and corresponding 95% confidence intervals (95% CI). We did not carry out any prespecified subgroup analyses. The primary efficacy outcome was improvement on any validated symptomatic rating scale. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We included three RCTs, assessed at low to moderate overall risk of bias, which randomised 313 participants with blepharospasm. Two studies excluded participants with poorer prior responses to BtA treatment, therefore, they included an enriched population with a higher probability of benefiting from this therapy. All trials were industry-funded. All RCTs evaluated the effect of a single BtA treatment session. BtA resulted in a moderate to large improvement in blepharospasm-specific severity, with a reduction of 0.93 points on the Jankovic Rating Scale (JRS) severity subscale at four to six weeks after injection (95% confidence interval (CI) 0.61 to 1.25; I² = 9%) compared to placebo. BtA was also resulted in a moderate to large improvement in blepharospasm-specific disability and blepharospasm-specific involuntary movements at four to six weeks after injection (disability: 0.69 JRS disability subscale points, 95% CI 0.18 to 1.19; I² = 74%; blepharospasm-specific involuntary movements: standardised mean difference (SMD) 0.79, 0.31 to 1.27; I² = 58%) compared to placebo. BtA did not show a risk of adverse events (risk ratio (RR) 1.18, 95% CI 0.87 to 1.60; I² = 0%). However, BtA increased the risk of vision complaints and eyelid ptosis (vision complaints: RR 5.73, 95% CI 1.79 to 18.36; I² = 51%; eyelid ptosis: RR 4.02, 95% CI 1.61 to 10.00; I² = 39%). There was no distinction between BtA and placebo in the number of participants who dropped out of the trial. A single trial estimated the duration of effects to be 10.6 weeks (range 6.1 to 19.1). We found no evidence supporting the existence of a clear dose-response relationship with BtA. We found no data reporting the impact of BtA on health-related quality of life, or the development of secondary non-responsiveness.

AUTHORS' CONCLUSIONS

We are moderately certain that a single BtA treatment resulted in a clinically relevant reduction of blepharospasm-specific severity and disability, and have low certainty that it is well tolerated, when compared with placebo. There is low-certainty evidence that people treated with BtA are not at an increased risk of developing adverse events, though BtA treatment likely increases the risk of visual complaints and eyelid ptosis. There are no data from RCTs evaluating the effectiveness and safety of repeated BtA injection cycles. There is no evidence from RCTs to allow us to draw definitive conclusions on the optimal treatment intervals and doses, or the impact on quality of life.

Botulinum toxin type A therapy for hemifacial spasm

BACKGROUND

This is an update of a Cochrane Review, first published in 2005. Hemifacial spasm (HFS) is characterised by unilateral, involuntary contractions of the muscles innervated by the facial nerve. It is a chronic disorder, and spontaneous recovery is very rare. The two treatments routinely available are microvascular decompression and intramuscular injections with botulinum toxin type A (BtA).

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus placebo in people with HFS.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, reference lists of articles, and conference proceedings in July 2020. We ran the electronic database search, with no language restrictions, in July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with HFS.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records. We planned to select included studies, extract data using a paper pro forma, and evaluate the risk of bias. We resolved disagreements by consensus, or by consulting a third review author. We planned to perform meta-analyses. The primary efficacy outcome was HFS-specific improvement. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We found no parallel-group randomised controlled trials comparing BtA and placebo in HFS.

AUTHORS' CONCLUSIONS

We did not find any randomised trials that evaluated the efficacy and safety of botulinum toxin type A in people with hemifacial spasm, so we are unable to draw any conclusions. Observational data show a strong association between BtA treatment and symptom improvement, and a favourable safety profile. While it is unlikely that future placebo-controlled RCTs will evaluate absolute efficacy and safety, they should address relevant questions for both people with HFS (such as long-term effects, quality of life, and other patient-reported outcomes), and clinicians (such as relative effectiveness of different BtA formulations and schemes of treatment) to better guide clinical practice.).

Botulinum toxin type A therapy for cervical dystonia

BACKGROUND

This is an update of a Cochrane Review first published in 2005. Cervical dystonia is the most common form of focal dystonia, and is a highly disabling movement disorder, characterised by involuntary, usually painful, head posturing. Currently, botulinum toxin type A (BtA) is considered the first line therapy for this condition.

OBJECTIVES

To compare the efficacy, safety, and tolerability of BtA versus placebo, in people with cervical dystonia.

SEARCH METHODS

We searched Cochrane Movement Disorders' Trials Register, CENTRAL, MEDLINE, Embase, reference lists of articles, and conference proceedings in July 2020. All elements of the search, with no language restrictions, were last run in July 2020.

SELECTION CRITERIA

Double-blind, parallel, randomised, placebo-controlled trials (RCTs) of BtA versus placebo in adults with cervical dystonia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed records, selected included studies, extracted data using a paper pro forma, and evaluated the risk of bias. We resolved disagreements by consensus or by consulting a third review author. We performed meta-analyses using a random-effects model, for the comparison of BtA versus placebo, to estimate pooled effects and corresponding 95% confidence intervals (95% CI). We performed preplanned subgroup analyses according to BtA dose used, the BtA formulation used, and the use (or not) of guidance for BtA injections. The primary efficacy outcome was improvement in cervical dystonia-specific impairment. The primary safety outcome was the proportion of participants with any adverse event.

MAIN RESULTS

We included nine RCTs, with moderate, overall risk of bias, that included 1144 participants with cervical dystonia. Seven studies excluded participants with poorer responses to BtA treatment, therefore, including an enriched population with a higher probability of benefiting from this therapy. Only one trial was independently funded. All RCTs evaluated the effect of a single BtA treatment session, using doses from 150 U to 500 U of onabotulinumtoxinA (Botox), 120 U to 240 U of incobotulinumtoxinA (Xeomin), and 250 U to 1000 U of abobotulinumtoxinA (Dysport). BtA resulted in a moderate to large improvement from the participant's baseline clinical status, assessed by the investigators, with a mean reduction of 8.09 points in the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS total score) at week four after injection (95% CI 6.22 to 9.96; I² = 0%) compared to placebo. This corresponded, on average, to a 18.4% improvement from baseline. The mean difference (MD) in TWSTRS pain subscore at week four was 2.11 (95% CI 1.38 to 2.83; I² = 0%) compared to placebo. Overall, both participants and clinicians reported an improvement of subjective clinical status. It was unclear if dropouts due to adverse events differed (risk ratio (RR) 2.51; 95% CI 0.42 to 14.94; I² = 0%) However, BtA treatment increased the risk of experiencing an adverse event (R) 1.23; 95% CI 1.05 to 1.43; I² = 28%). Neck weakness (14%; RR 3.40; 95% CI 1.19 to 9.71; I² = 15%), dysphagia (11%; RR 3.19; 95% CI 1.79 to 5.70; I² = 0%), and diffuse weakness or tiredness (8%; RR 1.80; 95% CI 1.10 to 2.95; I² = 0%) were the most common treatment-related adverse events. Treatment with BtA resulted in a decreased risk of dropouts. We have moderate certainty in the evidence across all of the aforementioned outcomes, with the exception of subjective assessment and tolerability, in which we have high confidence in the evidence. We found no evidence supporting the existence of a clear dose-response relationship between BtA and improvement in cervical dystonia-specific impairment, a destinction between BtA formulations, or a variation with use of EMG-guided injection for efficacy outcomes. Due to clinical heterogeneity, we did not pool health-related quality of life data, duration of clinical effect, or the development of secondary non-responsiveness.

AUTHORS' CONCLUSIONS

We are moderately certain in the evidence that a single BtA treatment session resulted in a clinically relevant reduction of cervical dystonia-specific impairment, and pain, and highly certain that it is well tolerated, compared with placebo. There is moderate-certainty evidence that people treated with BtA are at an increased risk of developing adverse events, most notably, dysphagia, neckweakness and diffuse weakness or tiredness. There are no data from RCTs evaluating the effectiveness and safety of repeated BtA injection cycles. There is no evidence from RCTs to allow us to draw definitive conclusions on the optimal treatment intervals and doses, the usefulness of guidance techniques for injection, the impact on quality of life, or the duration of treatment effect.

Catch and Anchor Approach To Combat Both Toxicity and Longevity of Botulinum Toxin A

Botulinum neurotoxins have remarkable persistence (∼weeks to months in cells), outlasting the small-molecule inhibitors designed to target them. To address this disconnect, inhibitors bearing two pharmacophores-a zinc binding group and a Cys-reactive warhead-were designed to leverage both affinity and reactivity. A series of first-generation bifunctional inhibitors was achieved through structure-based inhibitor design. Through X-ray crystallography, engagement of both the catalytic Zn2+ and Cys165 was confirmed. A second-generation series improved on affinity by incorporating known reversible inhibitor pharmacophores; the mechanism was confirmed by exhaustive dialysis, mass spectrometry, and in vitro evaluation against the C165S mutant. Finally, a third-generation inhibitor was shown to have good cellular activity and low toxicity. In addition to our findings, an alternative method of modeling time-dependent inhibition that simplifies assay setup and allows comparison of inhibition models is discussed.

Techniques and devices for the endoscopic treatment of gastroparesis (with video)

BACKGROUND AND AIMS

Gastroparesis is a symptomatic chronic disorder of the stomach characterized by delayed gastric emptying in the absence of mechanical obstruction. Several endoscopic treatment modalities have been described that aim to improve gastric emptying and/or symptoms associated with gastroparesis refractory to dietary and pharmacologic management.

METHODS

In this report we review devices and techniques for endoscopic treatment of gastroparesis, the evidence regarding their efficacy and safety, and the financial considerations for their use.

RESULTS

Endoscopic modalities for treatment of gastroparesis can be broadly categorized into pyloric, nonpyloric, and nutritional therapies. Pyloric therapies such as botulinum toxin injection, stent placement, pyloroplasty, and pyloromyotomy specifically focus on pylorospasm as a therapeutic target. These interventions aim to reduce the pressure gradient across the pyloric sphincter, with a resultant improvement in gastric emptying. Nonpyloric therapies, such as venting gastrostomy and gastric electrical stimulation, are intended to improve symptoms. Nutritional therapies, such as feeding tube placement, aim to provide nutritional support.

CONCLUSIONS

Several endoscopic interventions have shown utility in improving the quality of life and symptoms of select patients with refractory gastroparesis. Methods to identify which patients are best suited for a specific treatment are not well established. Endoscopic pyloromyotomy is a relatively recent development that may prove to be the preferred pyloric-directed intervention, although additional and longer-term outcomes are needed.

Duplication of clostridial binding domains for enhanced macromolecular delivery into neurons

Neurological diseases constitute a quarter of global disease burden and are expected to rise worldwide with the ageing of human populations. There is an increasing need to develop new molecular systems which can deliver drugs specifically into neurons, non-dividing cells meant to last a human lifetime. Neuronal drug delivery must rely on agents which can recognise neurons with high specificity and affinity. Here we used a recently introduced ‘stapling’ system to prepare macromolecules carrying duplicated binding domains from the clostridial family of neurotoxins. We engineered individual parts of clostridial neurotoxins separately and combined them using a strong alpha-helical bundle. We show that combining two identical binding domains of tetanus and botulinum type D neurotoxins, in a sterically defined way by protein stapling, allows enhanced intracellular delivery of molecules into neurons. We also engineered a botulinum neurotoxin type C variant with a duplicated binding domain which increased enzymatic delivery compared to the native type C toxin. We conclude that duplication of the binding parts of tetanus or botulinum neurotoxins will allow production of high avidity agents which could deliver imaging reagents and large therapeutic enzymes into neurons with superior efficiency.

•

Macromolecules carrying duplicated clostridial binding domains (Hc) were produced.

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Double tetanus Hc increased protein delivery into cultured rodent neurones.

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Double tetanus Hc increased enzyme delivery into rodent spinal cord and brain area.

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Double BoNT/D Hc increased enzyme delivery into rat and human neurones in culture.

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Recombinant double-Hc BoNT/C was engineered, increasing delivery in cell cultures.

Symptomatic Brain Hemorrhages from Cavernous Angioma After Botulinum Toxin Injections, a Role of TLR/MEKK3 Mechanism? Case Report and Review of the Literature

BACKGROUND

Cavernous angiomas (CAs) are vascular malformations that may result in stroke.

CASE DESCRIPTION

Herein, we evaluate a CA patient with chronic migraine who experienced 2 documented symptomatic hemorrhages after receiving respective high doses of botulinum toxin (Btx).

CONCLUSIONS

Recently, bacterial lipopolysaccharide has been reported to contribute to CA development through Toll-like receptor signaling, causing hemorrhagic angiogenic proliferation. Lipopolysaccharide and Btx share a common intracellular signaling pathway driving CA development and hemorrhage. Significance of these observations is demonstrated by previous works on plasma molecules showing prognostic associations with symptomatic hemorrhages in human CA, related to the same canonical pathways. Authors suggest careful tracking of the association of Btx and hemorrhage in CA patients.

Clinical relevance of neutralizing antibodies in botulinum toxin long-term treated still-responding patients with cervical dystonia

Background:

The aim of the study was to test the clinical relevance of neutralizing antibodies (NABs) in patients with cervical dystonia (CD) still responding to repeat injections with botulinum toxin type A (BoNT/A).

Methods:

Enzyme-linked immunosorbent assay (ELISA)-test evidence from a cross-sectional study on 221 CD-patients with treatment durations of between 2 and 21 years and still responding to repeat BoNT/A-injections showed the presence of antibodies against BoNT/A in 39 patients. A mouse hemi-diaphragm (MHDA) confirmation test was performed in these 39 ELISA-positive patients, and demographic (age, sex, age at onset of CD) and treatment-related (duration of treatment, mean dose of the last 10 injections, TSUI-score, patient’s subjective scoring of the treatment effect, patient’s scoring of quality of life by means of the CDQ24-questionnaire) data from these 39 patients were compared with data from ELISA-negative patients. Paralysis time, the MHDA outcome measure, was correlated with clinical data.

Results:

The ELISA-positive CD-patients had significantly higher TSUI-scores (p < 0.015), and had been treated for significant longer (p < 0.022) and with significantly higher doses (p < 0.001). Patient’s rating of BoNT/A-treatment effect and quality of life tended to be worse in ELISA-positive compared with ELISA-negative patients. The paralysis time of ELISA-positive patients was significantly correlated with the mean dose of the last 10 injections (p < 0.027) and the pain subscore of the CDQ24 (p < 0.012).

Conclusions:

Presence of NABs is clinically relevant in CD, leading to a significantly worse head position, therapy with significantly higher BoNT/A doses, and a correlation between the CDQ24 pain-subscore and antibody titers.

IncobotulinumtoxinA for the Treatment of Glabellar Frown Lines: A Prospective, Multicenter, Single-arm Study in Taiwan

Objective: We assessed clinical effectiveness, longevity of treatment effects, and patient satisfaction with incobotulinumtoxinA for glabellar frown lines (GFL) treatment in Asian patients. Design, Setting, and Participants: This was a prospective, multicenter, single-arm, open-label study at six sites in Taiwan. Patients aged 20 to 65 years with mild to very severe GFLs (Merz scale: 1-4 points) were eligible; 45 patients [including 23 BoNT/A-naïve and 22 previously-treated ("switch") patients were enrolled. Patients received intramuscular incobotulinumtoxinA injection at up to five injection points. Total doses ranged from 12 to 20U. Measurements: Investigators assessed improvements in dynamic GFLs at Days 14 and 120 using the validated five-point Merz scale (0=no lines; 4=very severe lines). Treatment satisfaction was self-reported by patients via questionnaire. Results: All patients showed excellent response to treatment in that Merz scores at Day 14 were 0 or 1 point(s). Both groups showed a mean improvement of 2.9 points; the response rate (1-point improvement or more from baseline) was 100 percent. GFL improvement was maintained over at least four months in both groups (mean improvements at Day 120: 1.5 points, naïve; 1.7 points, switch). Patient satisfaction ratings remained high (almost 100% in both groups) throughout the study. There were no statistically significant differences between groups regarding treatment satisfaction or GFL improvement (Merz score) at Days 14 and 120. No adverse events occurred. Conclusion: In Asian patients, incobotulinumtoxinA treatment for dynamic GFLs is effective and long lasting, with no expected differences between BoNT/A-naïve patients and those switching from other BoNT/As. IncobotulinumtoxinA yields consistent and natural-looking results for first and subsequent treatments.

The burden of sialorrhoea in chronic neurological conditions: current treatment options and the role of incobotulinumtoxinA (Xeomin®)

Sialorrhoea is a frequent symptom of neurological diseases (e.g. Parkinson’s disease, motor neuron disease, cerebral palsy, and stroke) and is defined as excessive saliva accumulation leading to unintentional loss of saliva from the mouth. Sialorrhoea increases the overall burden on the patient and their caregivers, the impact of which can be both physical and psychosocial. Treatments for sialorrhoea range from lifestyle and behavioural guidance, to medications, surgery or radiation. Nonpharmacological interventions include advice on posture, swallowing control, cough management, dietary changes, eating and drinking techniques, and behavioural modification; however, these conservative measures may be ineffective for people with progressive neurological conditions. The pharmacological treatment of sialorrhoea is challenging because medications licensed for this purpose are limited, but treatments can include anticholinergic drugs and botulinum toxins. Surgical treatment of sialorrhoea is typically reserved as a last resort for patients. IncobotulinumtoxinA (Xeomin®) is the first botulinum toxin type A to receive US and UK marketing authorization for the symptomatic treatment of chronic sialorrhoea due to neurological disorders in adults. In this review, we discuss and compare the frequency and method of administration, location of treatment delivery, approximate annual costs and main side effects of botulinum toxin and different anticholinergic drugs. Management of patients with chronic neurological conditions requires input from multiple specialist teams and thus a multidisciplinary team (MDT) approach is considered fundamental to ensure that care is consistent and tailored to patients’ needs. To ensure that adult patients with neurological conditions receive the best care and sialorrhoea is well managed, we suggest a potential clinical care pathway for sialorrhoea with a MDT approach, which healthcare professionals could aspire to.