Botulinum toxin type a blocks aquaporin 5 trafficking by decreasing synaptosomal-associated protein 23 in submandibular acinar cells.

The trafficking of aquaporin 5 (AQP5) is critical for salivary secretion. Synaptosomal-associated protein 23 (SNAP23) is an important regulator in the process of membrane fusion. However, the role of SNAP23 on AQP5 trafficking has not been explored. Botulinum toxin type A (BoNT/A) is a bacterial toxin that effectively treats sialorrhea. We previously reported that BoNT/A induced AQP5 redistribution in cultured acinar cells, but the mechanism remained unclear. In this study, SNAP23 was predominantly localized to the plasma membrane of acinar cells in the rat submandibular gland (SMG) and colocalized with AQP5 at the apical membrane of acinar cells. In stable GFP-AQP5-transfected SMG-C6 cells, the acetylcholine receptor agonist carbachol (CCh) induced trafficking of AQP5 from intracellular vesicles to the apical membrane. Furthermore, SNAP23 knockdown by siRNA significantly inhibited CCh-induced AQP5 trafficking, whereas this inhibitory effect was reversed by SNAP23 re-expression, indicating that SNAP23 was essential in AQP5 trafficking. More importantly, BoNT/A inhibited salivary secretion from SMGs, and the underlying mechanism involved that BoNT/A blocked CCh-triggered AQP5 trafficking by decreasing SNAP23 in acinar cells. Taken together, these results identified a crucial role for SNAP23 in AQP5 trafficking and provided new insights into the mechanism of BoNT/A in treating sialorrhea and thereby a theoretical basis for clinical applications.

Exploring the effects of extracranial injections of botulinum toxin type A on activation and sensitization of central trigeminovascular neurons by cortical spreading depression in male and female rats.

BACKGROUND: OnabotulinumtoxinA (onabotA), is assumed to achieve its therapeutic effect in migraine through blocking activation of unmyelinated meningeal nociceptors and their downstream communications with central dura-sensitive trigeminovascular neurons in the spinal trigeminal nucleus (SPV). The present study investigated the mechanism of action of onabotA by assessing its effect on activation and sensitization of dura-sensitive neurons in the SPV by cortical spreading depression (CSD). It is a follow up to our recent study on onabotA effects on activation and sensitization of peripheral trigeminovascular neurons. METHODS: In anesthetized male and female rats, single-unit recordings were used to assess effects of extracranial injections of onabotA (five injections, one unit each, diluted in 5 µl of saline were made along the lambdoid (two injection sites) and sagittal (two injection sites) suture) vs. vehicle on CSD-induced activation and sensitization of high-threshold (HT) and wide-dynamic range (WDR) dura-sensitive neurons in the SPV. RESULTS: Single cell analysis of onabotA pretreatment effects on CSD-induced activation and sensitization of central trigeminovascular neurons in the SPV revealed the ability of this neurotoxin to prevent activation and sensitization of WDR neurons (13/20 (65%) vs. 4/16 (25%) activated neurons in the control vs. treated groups, p = 0.022, Fisher's exact). By contrast, onabotA pretreatment effects on CSD-induced activation and sensitization of HT neurons had no effect on their activation (12/18 (67%) vs. 4/7 (36%) activated neurons in the control vs. treated groups, p = 0.14, Fisher's exact). Regarding sensitization, we found that onabotA pretreatment prevented the enhanced responses to mechanical stimulation of the skin (i.e. responses reflecting central sensitization) in both WDR and HT neurons. In control but not treated WDR neurons, responses to brush (p = 0.004 vs. p = 0.007), pressure (p = 0.002 vs. p = 0.79) and pinch (p = 0.007 vs. 0.79) increased significantly two hours after CSD. Similarly, in control but not treated HT neurons, responses to brush (p = 0.002 vs. p = 0.79), pressure (p = 0.002 vs. p = 0.72) and pinch (p = 0.0006 vs. p = 0.28) increased significantly two hours after CSD. Unexpectedly, onabotA pretreatment prevented the enhanced responses of both WDR and HT neurons to mechanical stimulation of the dura (commonly reflecting peripheral sensitization). In control vs. treated WDR and HT neurons, responses to dural stimulation were enhanced in 70 vs. 25% (p = 0.017) and 78 vs. 27% (p = 0.017), respectively. CONCLUSIONS: The ability of onabotA to prevent activation and sensitization of WDR neurons is attributed to its preferential inhibitory effects on unmyelinated C-fibers. The inability of onabotA to prevent activation of HT neurons is attributed to its less extensive inhibitory effects on the thinly myelinated Aδ-fibers. These findings provide further pre-clinical evidence about differences and potentially complementary mechanisms of action of onabotA and calcitonin gene-related peptide-signaling neutralizing drugs.

Mobile digital gait analysis captures effects of botulinum toxin in hereditary spastic paraplegia.

BACKGROUND AND PURPOSE: Hereditary spastic paraplegias (HSPs) comprise a group of inherited neurodegenerative disorders characterized by progressive spasticity and weakness. Botulinum toxin has been approved for lower limb spasticity following stroke and cerebral palsy, but its effects in HSPs remain underexplored. We aimed to characterize the effects of botulinum toxin on clinical, gait, and patient-reported outcomes in HSP patients and explore the potential of mobile digital gait analysis to monitor treatment effects and predict treatment response. METHODS: We conducted a prospective, observational, multicenter study involving ambulatory HSP patients treated with botulinum toxin tailored to individual goals. Comparing data at baseline, after 1 month, and after 3 months, treatment response was assessed using clinical parameters, goal attainment scaling, and mobile digital gait analysis. Machine learning algorithms were used for predicting individual goal attainment based on baseline parameters. RESULTS: A total of 56 patients were enrolled. Despite the heterogeneity of treatment goals and targeted muscles, botulinum toxin led to a significant improvement in specific clinical parameters and an improvement in specific gait characteristics, peaking at the 1-month and declining by the 3-month follow-up. Significant correlations were identified between gait parameters and clinical scores. With a mean balanced accuracy of 66%, machine learning algorithms identified important denominators to predict treatment response. CONCLUSIONS: Our study provides evidence supporting the beneficial effects of botulinum toxin in HSP when applied according to individual treatment goals. The use of mobile digital gait analysis and machine learning represents a novel approach for monitoring treatment effects and predicting treatment response.

OnabotulinumtoxinA as a promising treatment for primary trochlear headache: A retrospective case series.

OBJECTIVES: To report the efficacy of onabotulinumtoxinA (BoNTA) injections in relieving pain in patients with primary trochlear headache (PRTH). METHODS: Examination of medical records for patients diagnosed with PRTH according to the International Classification of Headache Disorders, 3rd edition criteria and treated with BoNTA. Data were collected for variables related to pain relief, duration of effectiveness, and adverse effects. RESULTS: Six patients were included in the study. All had previously undergone standard care interventions, including infiltrations or oral treatments, yet experienced treatment failure or symptom recurrence. All patients received 20 units of BoNTA, administered in the corrugator and procerus muscles. Subsequent to the BoNTA injections, all six patients reported substantial pain relief, with five achieving complete remission of symptoms. The analgesic effect persisted for a duration of 3 months. No adverse events were reported in any of the cases. CONCLUSIONS: Our case series presents the first evidence of the potential of BoNTA as a safe and effective treatment option for PRTH. From a clinical standpoint, having a safer alternative is of paramount significance for patients with limited treatment options, such as those with PRTH. Further research is warranted to validate these findings and explore the long-term efficacy of BoNTA in PRTH management.

Early effect of onabotulinumtoxinA on EEG-based functional connectivity in patients with chronic migraine: A pilot study.

OBJECTIVE: In this pilot prospective cohort study, we aimed to evaluate, using high-density electroencephalography (HD-EEG), the longitudinal changes in functional connectivity (FC) in patients with chronic migraine (CM) treated with onabotulinumtoxinA (OBTA). BACKGROUND: OBTA is a treatment for CM. Several studies have shown the modulatory action of OBTA on the central nervous system; however, research on migraine is limited. METHODS: This study was conducted at the Neurology Unit of "Policlinico Tor Vergata," Rome, Italy, and included 12 adult patients with CM treated with OBTA and 15 healthy controls (HC). Patients underwent clinical scales at enrollment (T0) and 3 months (T1) from the start of treatment. HD-EEG was recorded using a 64-channel system in patients with CM at T0 and T1. A source reconstruction method was used to identify brain activity. FC in δ-θ-α-ß-low-γ bands was analyzed using the weighted phase-lag index. FC changes between HCs and CM at T0 and T1 were assessed using cross-validation methods to estimate the results' reliability. RESULTS: Compared to HCs at T0, patients with CM showed hyperconnected networks in δ (p = 0.046, area under the receiver operating characteristic curve [AUC: 0.76-0.98], Cohen's κ [0.65-0.93]) and ß (p = 0.031, AUC [0.68-0.95], Cohen's κ [0.51-0.84]), mainly involving orbitofrontal, occipital, temporal pole and orbitofrontal, superior temporal, occipital, cingulate areas, and hypoconnected networks in α band (p = 0.029, AUC [0.80-0.99], Cohen's κ [0.42-0.77]), predominantly involving cingulate, temporal pole, and precuneus. Patients with CM at T1, compared to T0, showed hypoconnected networks in δ band (p = 0.032, AUC [0.73-0.99], Cohen's κ [0.53-0.90]) and hyperconnected networks in α band (p = 0.048, AUC [0.58-0.93], Cohen's κ [0.37-0.78]), involving the sensorimotor, orbitofrontal, cingulate, and temporal cortex. CONCLUSION: These preliminary results showed that patients with CM presented disrupted EEG-FC compared to controls restored by a single session of OBTA treatment, suggesting a primary central modulatory action of OBTA.

Sequential administration of peripheral nerve blocks and onabotulinumtoxinA for the treatment of chronic migraine and other headache disorders-A retrospective tolerability and safety study.

OBJECTIVE: To determine the tolerability and safety of concurrent peripheral nerve blocks and onabotulinumtoxinA treatment during a single outpatient clinic procedure visit. BACKGROUND: Procedural interventions are available for the treatment of headache disorders. OnabotulinumtoxinA and peripheral nerve blocks are used as alternatives or in addition to oral therapies to reduce the frequency and intensity of migraine attacks. There is currently a lack of safety data focusing on the sequential administration of local anesthetic via peripheral nerve blocks and onabotulinumtoxinA during a single clinical encounter for the treatment of headache. The primary aim of the study was to determine the safety and tolerability of concurrent peripheral nerve blockade and onabotulinumtoxinA injections during a single outpatient clinic procedure visit. We hypothesized that the dual intervention would be safe and well tolerated by patients with chronic migraine and other headache disorders. METHODS: A retrospective chart review was performed using clinical data from patients seen by multiple providers over a 16-month timeframe at one outpatient headache clinic. Patients were identified by procedure codes and those receiving peripheral nerve block(s) and onabotulinumtoxinA injections during a single encounter within the study period were eligible for inclusion. Inclusion criteria were (1) patients 18 years and older who were (2) receiving both peripheral nerve blocks and onabotulinumtoxinA injections for the treatment of chronic migraine. Patients were excluded if they were under age 18, received their procedure outside of the clinic (emergency room, inpatient ward), or were receiving sphenopalatine ganglion blocks. Age- and sex-matched patients who received one procedure, either peripheral nerve blocks or onabotulinumtoxinA, were used for control. The primary outcome of this safety study was the number of adverse events that occurred in the dual intervention group compared to the single intervention control arms. Information regarding adverse events was gathered via retrospective chart review. If an adverse event was recorded, it was then graded by the reviewer utilizing the Common Terminology Criteria for Adverse Events ranging from Grade 1 Mild Event to Grade 5 Death. Additionally, it was noted whether the adverse event led to treatment discontinuation. RESULTS: In total, 375 patients were considered eligible for inclusion in the study. After age and sex matching of controls, 131 patients receiving dual intervention were able to be compared to 131 patients receiving onabotulinumtoxinA alone and 104 patients receiving dual intervention were able to be compared to 104 patients receiving peripheral nerve block(s) alone. The primary endpoint analysis showed no significant difference in total adverse events between dual intervention compared to nerve blocks alone or onabotulinumtoxinA alone. The number of adverse events that led to treatment discontinuation approached but did not reach statistical significance for those receiving dual intervention versus onabotulinumtoxinA alone in the number of adverse events that led to treatment termination (4.6%, 6/131 vs. 0.8%, 1/131, p = 0.065); however, the number of patients who discontinued therapy was not significantly different between those groups (2.3%, 3/131 vs. 0.8%, 1/131; p = 0.314; odds ratio 0.3 [0-3.2]; p = 0.338). CONCLUSIONS: In this retrospective chart review, there was no significant difference in adverse events or therapy discontinuation between patients receiving sequential peripheral nerve block(s) and onabotulinumtoxinA injections versus those receiving either peripheral nerve block(s) or onabotulinumtoxinA injections alone. As a result, we concluded that the combination procedure is likely safe and well tolerated in routine clinical practice.

The impact of the migraine treatment onabotulinumtoxinA on inflammatory and pain responses: Insights from an animal model.

OBJECTIVE: Migraine, a prevalent and debilitating disease, involves complex pathophysiology possibly including inflammation and heightened pain sensitivity. The current study utilized the complete Freund's adjuvant (CFA) model of inflammation, with onabotulinumtoxinA (BoNT/A) as a treatment of interest due to its use in clinical migraine management. Using an animal model, the study sought to investigate the role of BoNT/A in modulating CFA-induced inflammation, alterations in pain sensitivity, and the regulation of calcitonin gene-related peptide (CGRP) release. Further, we aimed to assess the changes in SNAP-25 through western blot analysis to gain insights into the mechanistic action of BoNT/A. METHODS: BoNT/A or control was administered subcutaneously at the periorbital region of rats 3 days before the induction of inflammation using CFA. Periorbital mechanical sensitivity was assessed post-inflammation, and alterations in CGRP release were evaluated. Changes in SNAP-25 levels were determined using western blot analysis. RESULTS: Upon CFA-induced inflammation, there was a marked increase in periorbital mechanical sensitivity, with the inflammation side showing increased sensitivity compared to other periorbital areas. BoNT/A did decrease the withdrawal thresholds in the electronic von Frey test. Despite not being able to observe differences in pain thresholds or CGRP release, BoNT/A reduced baseline release under CFA inflamed conditions. Analysis of SNAP-25 levels in the trigeminal ganglion revealed both intact and cleaved forms that were notably elevated in BoNT/A-treated animals. These findings, derived from western blot analysis, suggest an effect on neurotransmitter release. CONCLUSION: Our investigation highlights the role of BoNT/A in reducing baseline CGRP in the context of inflammation and its involvement in SNAP-25 cleavage. In contrast, BoNT/A did not appear to alter facial pain sensitivity induced by inflammation, suggesting that mechanisms other than baseline CGRP could be implicated in the elevated thresholds in the CFA model.

Improvement of neurogenic urinary dysfunctions in female rats treated with an injection of botulinum toxin A at the epicenter of the spinal cord injured site.

OBJECTIVE: To assess the effect of an injection of botulinum toxin A (BoNT/A) at the epicenter of the spinal cord injury (SCI) site on the recovery of lower urinary tract function in female rats with thoracic SCI. MATERIALS AND METHODS: Twenty-four female Wistar rats with Sham (laminectomy at T8/T9 level) or SCI (at T8/T9; 30 g compression for 5 s) were assigned into Sham-SS (injected with 5 µL of saline solution), Sham-BoNT/A (injected with 15 pg/rat, equivalent to 7.5 Units/kg of BoNT/A in 5 µL volume), SCI-SS (injured and injected with saline), SCI-BoNT/A (injured and injected with BoNT/A), N = 6 per group. Weekly evaluation of stereotyped micturition behavior, hind-limb nociception, and locomotor activity was performed 1 week before and during 6 weeks after surgery. Subsequently, all groups underwent simultaneous electromyography of the external urethral sphincter (EUS-EMG) and cystometric (CMG) studies. RESULTS: A compression SCI at the T8/T9 thoracic level significantly impairs sensory and locomotive functions, as well as stereotyped micturition behavior. However, these impairments were improved by BoNT/A injection after SCI. Neither injections of saline solution nor BoNT/A had an appreciable effect on the same parameters evaluated in the Sham groups. The combined EUS-EMG and CMG evaluations revealed important improvements of lower urinary tract physiology, particularly a reduction in the frequency of non-voiding contractions and the properties of EUS bursting activity indicated as the amplitude of the EUS-EMG signal and duration of burst electrical activity during effective voiding. CONCLUSION: The severe impairments on sensory and locomotive functions as well stereotyped micturition caused by an SCI could be potentially attenuated by an injection of a small amount of BoNT/A directly into the epicenter of the SCI region. A reduction in the release of neurotoxic neurotransmitters requiring the SNARE complex may be the mechanism triggered by BoNT/A to reduce neurotoxicity and hyperexcitability created in the SCI area to improve the survival of spinal cord cells involved in micturition.

Predicting non-response to intraglandular botulinum neurotoxin A injections for drooling in children with neurodevelopmental disabilities.

AIM: To develop robust multivariable prediction models for non-response to (1) submandibular botulinum neurotoxin A (BoNT-A) injections and (2) concurrent submandibular and parotid (four-gland) injections, to guide treatment decisions for drooling in children with neurodevelopmental disabilities, including cerebral palsy. METHOD: This was a retrospective cohort study including 262 children (155 males/107 females, median age 7 years 11 months [IQR 5 years 1 month], range 4 years 0 months - 17 years 11 months) receiving submandibular injections and 74 children (52 males/22 females, median age 7 years 7 months [IQR 4 years 3 months], range 4 years 9 months - 18 years 8 months) receiving four-gland injections. Multivariable logistic regression analyses were used to estimate associations between candidate predictors and non-response 8 weeks after injection. RESULTS: Ninety-six children (37%) were non-responders to submandibular injections, for which developmental age was the strongest predictor (adjusted odds ratio [aOR] 2.13; 95% confidence interval [CI] 1.02-4.45 for developmental age <4 years or 4-6 years with IQ <70). Other characteristics that showed a trend towards an increased risk of non-response were diagnosis, sex, and head position. Thirty-four children (46%) were non-responders to four-gland injections, for which tongue protrusion (aOR 3.10; 95% CI 1.14-8.43) seemed most predictive, whereas multiple preceding submandibular injections (aOR 0.34; 95% CI 0.10-1.16) showed a trend towards being protective. Predictors were, however, unstable across different definitions of non-response and both models (i.e. submandibular and four-gland) had insufficient discriminative ability. INTERPRETATION: Potential predictors of non-response to BoNT-A injections were identified. Nevertheless, the developed prediction models seemed inadequate for guidance of treatment decisions. WHAT THIS PAPER ADDS: Developmental age seemed most predictive of non-response to submandibular botulinum neurotoxin A injections. Non-response to concurrent submandibular and parotid injections was best predicted by tongue protrusion and number of previous injections. Multivariable prediction models including these clinical characteristics were unable to discriminate well. Predictors differed when non-response was defined using alternative outcome measures.

Effects of botulinum toxin in two indicators of loss of domain and hernia size among patients with large ventral hernias.

BACKGROUND: In patients with large ventral hernias, botulinum toxin to external and internal oblique muscles decreases thickness and increases length. We examined the impact of botulinum toxin in the amount of loss of domain according to two ratios and in hernia size. METHODS: Between October 2021 and November 2023, 20 patients with ventral hernias measuring 10 cm or more on the horizontal size underwent the administration of 50 units of botulinum toxin to each external and each internal oblique muscle 4 weeks before their surgery. Incisional hernia volume to peritoneal volume ratio, volume ratio, and hernia size were compared before and 4 weeks after the injection of botulinum toxin. Comparisons between all variables obtained before and after the administration of botulinum toxin were performed using either the paired t-test or the Wilcoxon signed-rank test. Pearson correlation coefficient was used to analyze associations between initial conditions and further changes observed after botulinum toxin injection. RESULTS: We observed a 42% reduction in muscle amplitude, 16% increase in intra-abdominal volume, 28% decrease in herniated volume, decreases of 6% in IHV/PV ratio and of 11% in V ratio, 11% reduction of hernia width, and decrease of 10% in rectangular and elliptical hernia areas. CONCLUSIONS: In patients with large ventral hernias, botulinum toxin is associated with reduction of hernia size and decrease in loss of domain, the latter not being significant when less than 10% of the visceral block is herniated.

Comparing the evidence for botulinum neurotoxin injections in paediatric anterior drooling: a scoping review.

Paediatric anterior drooling has a major impact on the daily lives of children and caregivers. Intraglandular botulinum neurotoxin type-A (BoNT-A) injections are considered an effective treatment to diminish drooling. However, there is no international consensus on which major salivary glands should be injected to obtain optimal treatment effect while minimizing the risk of side effects. This scoping review aimed to explore the evidence for submandibular BoNT-A injections and concurrent submandibular and parotid (i.e. four-gland) injections, respectively, and assess whether outcomes could be compared across studies to improve decision making regarding the optimal initial BoNT-A treatment approach for paediatric anterior drooling. PubMed, Embase, and Web of Science were searched to identify relevant studies (until October 1, 2023) on submandibular or four-gland BoNT-A injections for the treatment of anterior drooling in children with neurodevelopmental disabilities. Similarities and differences in treatment, patient, outcome, and follow-up characteristics were assessed. Twenty-eight papers were identified; 7 reporting on submandibular injections and 21 on four-gland injections. No major differences in treatment procedures or timing of follow-up were found. However, patient characteristics were poorly reported, there was great variety in outcome measurement, and the assessment of side effects was not clearly described.   Conclusion: This review highlights heterogeneity in outcome measures and patient population descriptors among studies on paediatric BoNT-A injections, limiting the ability to compare treatment effectiveness between submandibular and four-gland injections. These findings emphasize the need for more extensive and uniform reporting of patient characteristics and the implementation of a core outcome measurement set to allow for comparison of results between studies and facilitate the optimization of clinical practice guidelines. What is Known: • There is no international consensus on which salivary glands to initially inject with BoNT-A to treat paediatric drooling. What is New: • Concluding on the optimal initial BoNT-A treatment based on literature is currently infeasible. There is considerable heterogeneity in outcome measures used to quantify anterior drooling.and clinical characteristics of children treated with intraglandular BoNT-A are generally insufficiently reported. • Consensus-based sets of outcome measures and patient characteristics should be developed and implemented.

Intrauterine botulinum toxin A administration promotes endometrial regeneration mediated by IGFBP3-dependent OPN proteolytic cleavage in thin endometrium.

Adequate endometrial growth is a critical factor for successful embryo implantation and pregnancy maintenance. We previously reported the efficacy of intrauterine administration of botulinum toxin A (BoTA) in improving the endometrial angiogenesis and the rates of embryo implantation. Here, we further evaluated its potent therapeutic effects on the uterine structural and functional repair and elucidated underlying molecular regulatory mechanisms. This study demonstrated that a murine model of thin endometrium was successfully established by displaying dramatically decreased endometrial thickness and the rates of embryo implantation compared to normal endometrium. Interestingly, the expressions of insulin-like growth factor binding protein-3 (IGFBP3) and an active 35 kDa-form of osteopontin (OPN) were significantly reduced in thin endometrium, which were almost fully restored by intrauterine BoTA administration. Neutralization of BoTA-induced IGFBP3 subsequently suppressed proteolytic cleavage of OPN, exhibiting un-recovered endometrial thickness even in the presence of BoTA administration, suggesting that BoTA-induced endometrial regeneration might be mediated by IGFBP3-dependent OPN proteolytic cleavage. Our findings suggest that intrauterine BoTA administration improves the endometrial environment in our murine model with thin endometrium by increasing endometrial receptivity and angiogenesis in a manner dependent on the regulatory effect of IGFBP3 on OPN proteolytic cleavage, proposing BoTA as an efficient therapeutic strategy for the patients with thin endometrium.

In-vivo assessment of application of folinic acid and botulinum toxin A in cleft lip surgical defects.

INTRODUCTION: Folinic acid and botulinum toxin A have shown promising results in wound healing in different studies. This study aimed to compare the effects of these approaches on wound healing after simulating cleft lip surgery in rats. METHODS: In this experimental animal study, after creating lip defects, 30 rats were randomly divided into three groups and received normal saline (CTL), botulinum toxin A (BOT), and folinic acid (FOL). Biopsy from the skin wounds was performed after 14- and 28-days. These samples were stained with haematoxylin and eosin and Masson trichrome staining. Finally, each pathological parameter of wound healing was rated in this study. RESULTS: While the inflammatory response was not different among the study groups, fibroblast proliferation and collagen deposition were significantly higher in FOL group compared to BOT group. Moreover, both BOT and FOL facilitated epithelial healing and 14-day angiogenesis as compared with normal saline. CONCLUSIONS: Improved wound healing was observed using both botulinum toxin A and folinic acid in rat animal models. However, the application of botulinum toxin A caused less fibroblast proliferation and collagen deposition which can potentially lead to less scar formation, which can be particularly important in the aesthetic zone.

Onabotulinum toxin A improves neurogenic detrusor overactivity following spinal cord injury: a systematic review and meta-analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVES: The current study aimed to assess the efficacy and safety of Onabotulinum toxin A (OBTX-A) treatment for neurogenic detrusor overactivity (NDO) in spinal cord injury (SCI) patients. SETTING: Iran. METHODS: All relevant articles of clinical trials and cohort studies indexed in PubMed/MEDLINE, Embase, Scopus, and Web of Science databases up to September 6, 2022, that addressed OBTX-A treatment for NDO following SCI were included. The quality of eligible studies was evaluated using Cochrane criteria. Also, the weighted mean difference (WMD) was measured with a random-effect model. RESULTS: Regarding the overall efficacy after OBTX-A treatment in the short term, volume per void (VV) (WMD = 118.8, 95% CI: 90.9-146.7, p < 0.01), incontinence-quality of life (IQoL) (WMD = 24.3, 95% CI: 15.8-32.8, p < 0.01), and maximum cystometric capacity (MCC) (WMD = 144.5, 95% CI: 132.3 to 156.7, p < 0.01) significantly increased, while maximum detrusor pressure during storage (MDP) (WMD = -30.5, 95% CI: -35.9 to -25.1, p < 0.01) showed a significant decrease. Furthermore, compared to the placebo group at the 200-unit dose, there was a significant increase in MCC (WMD = 113.5, 95% CI: 84.7 to 142.3, p < 0.01) and a significant decrease in MDP (WMD = -27.2, 95% CI: -39.2 to -15.1, p < 0.01). Urinary tract infection (UTI), hematuria, and autonomic dysreflexia were the most common side effects, occurring at rates of 29.6%, 14.8%, and 13.4%, respectively. CONCLUSION: Our findings highlighted the effectiveness and safety of OBTX-A as a promising treatment of NDO following SCI.

The Role of Botulinum Neurotoxin A in the Conservative Treatment of Fractures: An Experimental Study on Rats.

This paper explores the role of botulinum neurotoxin in aiding fracture recovery through temporary muscle paralysis. Specifically, it investigates the effects of botulinum neurotoxin-induced paralysis of the sternocleidomastoid muscle on clavicle fractures in rats. The research aims to assess safety, effectiveness, and the impact on fracture healing. Healthy male Albino Wistar rats were divided into four groups: clavicle fracture, botulinum neurotoxin injection, both, and control. Surgeries were conducted under anaesthesia, and postoperatively, animals were monitored for 28 days. Euthanasia and radiological assessment followed, examining fracture healing and muscle changes, while tissues were histopathologically evaluated. The modified Lane-Sandhu scoring system was used for the radiographic evaluation of clavicle fractures, and the results varied from complete healing to nonunion. Histopathological examination at 28 days postfracture showed fibrous tissue, mesenchymal cells, and primary callus formation in all groups. Despite varied callus compositions, botulinum neurotoxin administration did not affect clavicle healing, as evidenced by similar scores to the control group. Several studies have explored botulinum neurotoxin applications in fracture recovery. Research suggests its potential to enhance functional recovery in certain types of fractures. Theoretical benefits include managing muscle spasticity, aiding reduction techniques, and preventing nonunion. However, botulinum neurotoxin's transient effect and nonuniversal applications should be considered. The present study found that botulinum toxin had no clear superiority in healing compared to controls, while histological evaluation showed potential adverse effects on muscle tissue. Further research is essential to understand its risk-benefit balance and long-term effects.

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

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

Tirbanibulin (KX2-391) analog KX2-361 inhibits botulinum neurotoxin serotype A mediated SNAP-25 cleavage in pre- and post-intoxication models in cells.

Botulinum neurotoxins (BoNT) inhibit neuroexocytosis, leading to the potentially lethal disease botulism. BoNT serotype A is responsible for most human botulism cases, and there are no approved therapeutics to treat already intoxicated patients. A growing body of research has demonstrated that BoNT/A can escape into the central nervous system, and therefore, identification of BoNT/A inhibitors that can penetrate BBB and neutralize the toxin within intoxicated neurons would be important. We previously identified an FDA-approved, orally bioavailable compound, KX2-391 (Tirbanibulin) that inhibits BoNT/A in motor neuron assays. Recently, a structural analog of KX2-391, KX2-361, has been shown to exhibit good oral bioavailability and cross BBB with high efficiency in mouse experiments. Therefore, in this work, we evaluated the inhibitory effects of KX2-361 against BoNT/A. Toward this goal, we first evaluated the compound for its effects on cell viability in PC12 cells, via MTT assay, and in mouse embryonic stem cell (mESC)-derived motor neurons, with imaging-based assays. Following, we tested KX2-361 in mESC-derived motor neurons intoxicated with BoNT/A holotoxin, and the compound exhibited activity against the toxin in both pre- and post-intoxication conditions. Excitingly, KX2-361 also inhibited BoNT/A enzymatic component (light chain; LC) in PC12 cells transfected with BoNT/A LC. Furthermore, our molecular docking analyses suggested that KX2-361 can directly bind to BoNT/A LC. Medicinal chemistry approaches to develop structural analogs of KX2-361 to increase its efficacy against BoNT/A may provide a critical lead compound with BBB penetration capacity for drug development efforts against BoNT/A intoxication.

Histomorphometric Changes of the Masseter Muscle of Rats After a Single Injection of Botulinum Toxin Type A.

BACKGROUND: It has been reported that botulinum toxin type A (BoNT-A) produces structural changes in masticatory muscles. However, not all histomorphometric parameters affected by BoNT-A parameters have been assessed. This study investigated the histomorphometric changes in the masseter muscle of rats after a single injection of BoNT-A. METHODS: Forty-four adult animals were randomly divided into control group (n = 22) and BoNT-A group (n = 22). Controls received a single dose of 0.14 mL/kg of saline in masseter muscles, and the BoNT-A group received a 7 U/Kg of BoNT-A. The groups received the same volume of injected substances. Animals were sacrificed on 7th (n = 5), 14th (n = 5), 21st (n = 5), 28th (n = 4) and 90th (n = 3) days post-treatment. Histological masseter tissue slides were obtained from hematoxylin-eosin treatment and analyzed in optical microscopy regarding muscle cross-sectional area, amount of connective tissue and quantity and diameter of myocytes. For statistical analysis, generalized linear models were used to compare the data (ANOVA). In all test, the significance level of 5% was set. RESULTS: BoNT-A values of cross-sectional area of the masseter muscle were significantly lower than controls (p < 0.01) throughout the study. Regarding myocytes quantity, BoNT-A subgroups presented higher values than controls (p < 0.0001) since the 14th day until the end of the study; however, the diameter of myocytes was smaller in all BoNT-A subgroups (p < 0.0001) in all assessment points. The amount of connective tissue was higher in BoNT-A subgroups (p < 0.0001) throughout the study. CONCLUSION: A single injection of BoNT-A altered the structure of masseter muscle of rats, regarding its histomorphometric parameters. NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Unilateral injection of botulinum toxin type A into the masseter muscle induces mandibular asymmetry in adolescent rats by suppressing the angular process growth.

INTRODUCTION: Mandibular asymmetry has negative impacts on maxillofacial aesthetics and psychological well-being. This study investigated the effects of unilateral injection of botulinum toxin type A (BTX-A) into the masseter muscle on mandibular symmetry. METHODS: Forty Wistar rats (4-week-old) were divided into 4 groups (n = 10): control, group 1 (1U BTX-A), group 2 (3U BTX-A), and group 3 (1U BTX-A for 3 times). BTX-A was injected into the right masseter of treatment groups. Cone-beam computerized tomography scans were taken before the injection and then at 2 weeks, 4 weeks, and 6 weeks after injection. Histologic and immunohistochemical staining were done for the condylar cartilage. RNA sequencing and quantitative reverse transcription polymerase chain reaction were used to detect gene expression in the angular process. RESULTS: In Groups 2 and 3, the right angular process length and the ramus height were reduced 4 weeks after injection, resulting in the mandibular midline deviating to the right side; the right condylar cartilage had reduced thickness and decreased expression of RUNX2, SOX9, and COL II (P <0.05). Two hundred sixty-one genes were differentially expressed (256 downregulated) in the angular process at 3 days post-BTX-A injection, and the calcium signaling pathway was unveiled through the Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis. Furthermore, TRPC1, Wnt5a, CaMKII, Ctnnb1, and RUNX2 expression were significantly downregulated at 1 and 3 days postinjection. CONCLUSIONS: Unilateral injection of BTX-A into the masseter muscle in adolescent rats induces mandibular asymmetry by suppressing the angular process growth on the injected side.

BAcTrace, a tool for retrograde tracing of neuronal circuits in Drosophila.

Animal behavior is encoded in neuronal circuits in the brain. To elucidate the function of these circuits, it is necessary to identify, record from and manipulate networks of connected neurons. Here we present BAcTrace (Botulinum-Activated Tracer), a genetically encoded, retrograde, transsynaptic labeling system. BAcTrace is based on Clostridium botulinum neurotoxin A, Botox, which we engineered to travel retrogradely between neurons to activate an otherwise silent transcription factor. We validated BAcTrace at three neuronal connections in the Drosophila olfactory system. We show that BAcTrace-mediated labeling allows electrophysiological recording of connected neurons. Finally, in a challenging circuit with highly divergent connections, BAcTrace correctly identified 12 of 16 connections that were previously observed by electron microscopy.