A Pilot Study of A2NTX, a Novel Low-Molecular-Weight Neurotoxin Derived from Subtype A2 for Post-Stroke Lower Limb Spasticity: Comparison with OnabotulinumtoxinA.

All the currently used type A botulinum neurotoxins for clinical uses are of subtype A1. We compared the efficacy and safety for the first time head-to-head between a novel botulinum toxin A2NTX prepared from subtype A2 and onabotulinumtoxinA (BOTOX) derived from A1 for post-stroke spasticity. We assessed the modified Ashworth scale (MAS) of the ankle joint, the mobility scores of Functional Independence Measure (FIM), and the grip power of the unaffected hand before and after injecting 300 units of BOTOX or A2NTX into calf muscles. The procedure was done in a blinded manner for the patient, the injecting physician, and the examiner. Stroke patients with chronic spastic hemiparesis (15 for A2NTX and 16 for BOTOX) were enrolled, and 11 for A2NTX and 13 for BOTOX (MAS of ankle; > or = 2) were entered for the MAS study. Area-under-curves of changes in MAS (primary outcome) were greater for A2NTX by day 30 (p = 0.044), and were similar by day 60. FIM was significantly improved in the A2NTX group (p = 0.005), but not in the BOTOX group by day 60. The hand grip of the unaffected limb was significantly decreased in the BOTOX-injected group (p = 0.002), but was unaffected in the A2NTX-injected group by day 60, suggesting there was less spread of A2NTX to the upper limb than there was with BOTOX. Being a small-sized pilot investigation with an imbalance in the gender of the subjects, the present study suggested superior efficacy and safety of A2NTX, and warrants a larger scale clinical trial of A2NTX to confirm these preliminary results.

Clinical Safety and Tolerability of A2NTX, a Novel Low-Molecular-Weight Neurotoxin Derived from Botulinum Neurotoxin Subtype A2, in Comparison with Subtype A1 Toxins.

All the botulinum type A neurotoxins available for clinical use are of the A1 subtype. We developed a subtype A2 low-molecular-weight (150 kD (kilo Dalton)) neurotoxin (A2NTX) with less spread and faster entry into the motor nerve terminal than A1 in vitro and in vivo. Preliminary clinical studies showed that its efficacy is superior to A1 toxins. We conducted an open study exploring its safety and tolerability profile in comparison with A1LL (LL type A1 toxin, or onabotulinumtoxinA) and a low-molecular-weight (150 kD) A1 neurotoxin (A1NTX). Those who had been using A1LL (n = 90; 50-360 mouse LD50 units) or A1NTX (n = 30; 50-580 units) were switched to A2NTX (n = 120; 25-600 units) from 2010 to 2018 (number of sessions ~27, cumulative doses ~11,640 units per patient). The adverse events for A2NTX included weakness (n = 1, ascribed to alcoholic polyneuropathy), dysphagia (1), local weakness (4), and spread to other muscles (1), whereas those for A1LL or A1NTX comprised weakness (n = 2, A1NTX), dysphagia (8), ptosis (6), local weakness (7), and spread to other muscles (15). After injections, 89 out of 120 patients preferred A2NTX to A1 for the successive sessions. The present study demonstrated that A2NTX had clinical safety up to the dose of 500 units and was well tolerated compared to A1 toxins.

Increased IP-10 production by blood-nerve barrier in multifocal acquired demyelinating sensory and motor neuropathy and multifocal motor neuropathy.

OBJECTIVE: Dysfunction of the blood-nerve barrier (BNB) plays important roles in chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). The aim of the present study was to identify the candidate cytokines/chemokines that cause the breakdown of the BNB using sera from patients with CIDP and MMN. METHODS: We determined the levels of 27 cytokines and chemokines in human peripheral nerve microvascular endothelial cells (PnMECs) after exposure to sera obtained from patients with CIDP variants (typical CIDP and multifocal acquired demyelinating sensory and motor neuropathy [MADSAM]), MMN and amyotrophic lateral sclerosis (ALS), and healthy controls (HC), using a multiplexed fluorescent bead-based immunoassay system. RESULTS: The induced protein (IP)10 level in the cells in both the MADSAM and MMN groups was markedly increased in comparison with the typical CIDP, ALS and HC groups. The other cytokines, including granulocyte colony-stimulating factor,vascular endothelial growth factor (VEGF) and interleukin-7, were also significantly upregulated in the MADSAM group. The increase of IP-10 produced by PnMECs was correlated with the presence of conduction block in both the MADSAM and MMN groups. CONCLUSION: The autocrine secretion of IP-10 induced by patient sera in PnMECs was markedly upregulated in both the MADSAM and MMN groups. The overproduction of IP-10 by PnMECs leads to the focal breakdown of the BNB and may help to mediate the transfer of pathogenic T cells across the BNB, thereby resulting in the appearance of conduction block in electrophysiological studies of patients with MADSAM and MMN.

MR Spectroscopy in Patients with Hereditary Diffuse Leukoencephalopathy with Spheroids and Asymptomatic Carriers of Colony-stimulating Factor 1 Receptor Mutation.

PURPOSE: Hereditary diffuse leukoencephalopathy with spheroids (HDLS) is a rare neurodegenerative disorder with various clinical presentations. Mutation of the colony-stimulating factor 1 receptor (CSF1R) gene is considered to be a cause of this autosomal dominant disorder. The purpose of this study was to report magnetic resonance spectroscopy (MRS) findings in patients with HDLS and asymptomatic carriers and to clarify the use of MRS in this disease. MATERIALS AND METHODS: In this retrospective, institutional review board-approved study, we included four consecutive patients, genetically diagnosed with HDLS, and two asymptomatic carriers after acquiring informed consent. We performed single-voxel MRS of the left centrum semiovale on a 3-T clinical scanner. We also included a sex-matched normal dataset. We quantified N-acetylaspartate (NAA), creatine, choline-containing compounds (Cho), glutamine, glutamate (Glu), myo-inositol (Ins), glutathione, lactate (Lac), and gamma-amino butyric acid using LCModel. We performed statistical analysis, and P value <0.05 was considered significant. RESULTS: In HDLS cases, MRS revealed decreased NAA and Glu concentrations, which probably reflected neuronal damage and/or loss, and a subsequent reduction of neurotransmitters. A patient with HDLS also had increased Cho and Ins concentrations, indicating gliosis, and increased Cho concentration was also observed in an asymptomatic carrier. This suggests that metabolic changes had already occurred in an asymptomatic state. CONCLUSION: We demonstrated changes in metabolite concentrations not only in patients with HDLS but also in asymptomatic CSF1R mutation carriers. Our study indicates that MRS is a potentially useful tool for the analysis of metabolic and pathophysiological findings of HDLS, even during the early stages of disease.

Late-onset spastic paraplegia: Aberrant SPG11 transcripts generated by a novel splice site donor mutation.

We identified a novel homozygous mutation in the splice site donor (SSD) of intron 30 (c.5866+1G>A) in consanguineous Japanese SPG11 siblings showing late-onset spastic paraplegia using the whole-exome sequencing. Phenotypic variability was observed, including age-at-onset, dysarthria and pes cavus. Coding DNA sequencing revealed that the mutation affected the recognition of the constitutive SSD of intron 30, splicing upstream onto a nearby cryptic SSD in exon 30. The use of constitutive splice sites of intron 29 was confirmed by sequencing. The mutant transcripts are mostly subject to degradation by the nonsense-mediated mRNA decay system. SPG11 transcripts, escaping from the nonsense-mediated mRNA decay pathway, would generate a truncated protein (p.Tyr1900Phefs5X) containing the first 1899 amino acids and followed by 4 aberrant amino acids. This study showed a successful clinical application of whole-exome sequencing in spastic paraplegia and demonstrated a further evidence of allelic heterogeneity in SPG11. The confirmation of aberrant transcript by splice site mutation is a prerequisite for a more precise molecular diagnosis.

Increased proinflammatory cytokines in sera of patients with multifocal motor neuropathy.

BACKGROUND: Multifocal motor neuropathy (MMN) is characterized by clinical improvement with intravenous immunoglobulin and the frequent detection of anti-ganglioside antibodies. However, the immunological background of the neuronal damage in MMN is still unclear. OBJECTIVE: The aim of this study is to investigate abnormalities in the cytokine and chemokine profiles of MMN patients. METHODS: Sera from 16 patients with MMN, 16 patients with sporadic amyotrophic lateral sclerosis (ALS), and 15 patients with other non-inflammatory neurological diseases (ONDs) were analyzed for 27 cytokines and chemokines using a multiplex bead array. We also checked whether the altered cytokine/chemokine profile in the MMN group differed significantly in the presence or absence of abnormal electrophysiological findings. RESULTS: Serum IL-1Ra, IL-2, G-CSF, TNF-α, and TNFR1 levels were significantly higher in the MMN group than in the ONDs group. Of these, G-CSF and TNF-α also showed significant increases compared to the ALS group. Serum G-CSF and TNF-α levels were significantly higher in MMN patients presenting with focal demyelination including conduction block than in patients without any focal demyelination. CONCLUSIONS: Proinflammatory cytokines may contribute to peripheral nerve demyelination in MMN.

Are multifocal motor neuropathy patients underdiagnosed? An epidemiological survey in Japan.

INTRODUCTION: Our objective was to do an epidemiologic survey of patients with multifocal motor neuropathy (MMN) in comparison with those with amyotrophic lateral sclerosis (ALS) in Japan. METHODS: In this retrospective study, we examined 46 patients with MMN and 1,051 patients with ALS from major neuromuscular centers in Japan from 2005 to 2009. Diagnosis was based on the European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/PNS) and the revised El Escorial criteria. The efficacy of intravenous immunoglobulin (IVIg) was also taken into consideration in the diagnosis of MMN. RESULTS: The ratio of MMN to ALS patients (0­0.10) varied among the centers, but mostly converged to 0.05. The prevalence was estimated to be 0.29 MMN patients and 6.63 ALS patients per 100,000 population. CONCLUSIONS: The frequency of MMN patients was around 1 out of 20 ALS patients, and MMN was possibly underdiagnosed in some centers.

Sera from patients with multifocal motor neuropathy disrupt the blood-nerve barrier.

OBJECTIVE: In multifocal motor neuropathy (MMN), the destruction of the blood-nerve barrier (BNB) has been considered to be the key step in the disease process. The purpose of the present study was to ascertain whether sera from patients with MMN can open the BNB, and which component of patient sera is the most important for this disruption. METHODS: We evaluated the effects of sera from patients with MMN, patients with amyotrophic lateral sclerosis, and control subjects on the expression of tight junction proteins and vascular cell adhesion molecule-1 (VCAM-1), and on the transendothelial electrical resistance (TEER) in human peripheral nerve microvascular endothelial cells (PnMECs). RESULTS: The sera from patients with MMN decreased the claudin-5 protein expression and the TEER in PnMECs. However, this effect was reversed after application of an anti-vascular endothelial growth factor (anti-VEGF) neutralising antibody. The VEGF secreted by PnMECs was significantly increased after exposure to the sera from patients with MMN. The sera from patients with MMN also increased the VCAM-1 protein expression by upregulating the nuclear factor kappa-B (NF-κB) signalling. The immunoglobulin G purified from MMN sera decreased the expression of claudin-5 and increased the VCAM-1 expression in PnMECs. CONCLUSIONS: The sera from MMN patients may disrupt the BNB function via the autocrine secretion of VEGF in PnMECs, or the exposure to autoantibodies against PnMECs that are contained in the MMN sera. Autoantibodies against PnMECs in MMN sera may activate the BNB by upregulating the VCAM-1 expression, thereby allowing for the entry of a large number of circulating inflammatory cells into the peripheral nervous system.

[Treatment of spasticity with botulinum toxin].

The beneficial effects of rehabilitation are known to plateau around 6 months after stroke. But there are some reports that motor functions are improved with using botulinum neurotoxin A (BoNT-A) for limb spasticity in the maintenance stage of stroke. Though it has been thought that BoNT-A works in the peripheral nerves so far, Caleo showed BoNT-A can affect the central nervous system. We suspected BoNT-A affected the spinal cord directly following retrograde transsynaptic transport from his reports. We deduce the abnormal stretch reflex is made a modification by affecting the spinal cord, and it follows that motor function.We suggest it is important BoNT-A injection immediately followed by intensive rehabilitation to regain active motor function, because BoNT-A has a specific affinity to cleave certain proteins involved in the mechanism of acetylcholine exocytosis. We propose BoNT-A treatment at 3-month interval should be set.

[Update of multifocal motor neuropathy].

We surveyed patients with multifocal motor neuropathy (MMN) in comparison with those with amyotrophic lateral sclerosis (ALS) in Japan. This retrospective study consisted of 47 patients with MMN and 1,051 patients with ALS from major neuromuscular centers in Japan from 2005 to 2009. The ratio of MMN to ALS patients (0-0.10) varied among the centers, but mostly converged to 0.05. The prevalence was estimated to be 0.3 cases for MMN and 6.63 cases for ALS per 100,000 persons. Twenty-seven of 47 patients (56.5%) showed conduction block (CB). Of the 45 patients who received intravenous immunoglobulin (MVg), 34(75.6 %) demonstrated clear clinical improvement.

[A case of cerebral air embolism developed during pleural lavage].

We report a patient with cerebral air embolism in whom we could perform serial brain magnetic resonance images (MRIs). A 78-year-old man was admitted to our hospital because of recurrent empyema after surgery for esophageal cancer. He suddenly demonstrated left hemiparesis in the middle of pleural lavage. After about 30 minutes from onset, the computed tomography (CT) revealed multiple air-isodense spots in the right hemisphere of the brain. After about 2 hours from onset, many hypointense spots in the right hemisphere were revealed on T2*-weighted image (T2*WI). These findings suggested cerebral air embolism. He didn't receive hyperbaric oxygen therapy because he had status epilepticus. The hypointense spots on the T2*WI became smaller and spread after 7 hours from onset and almost disappeared after 53 days. It is important to recognize that cerebral arterial air embolism is similar to multiple microbleeds and cerebral arteriovenous fistula in hypointense spots on the T2*WI.

[Treatment and indication of botulinum toxin type A for limb spasticity - can we break the 6 months barrier?].

It is common knowledge that recovery of motor function is limited at 6 months after the onset of stroke. But there are some reports that motor functions are improved with using botulinum toxin type A for limb spasticity in the maintenance stage of stroke. Though it has been thought that botulinum toxin type A works in the peripheral nerves so far, Caleo showed botulinum toxin can affect the central nervous system. We suspected botulinum toxin type A affected the spinal cord directly following retrograde transynaptic transport from our experiments and his reports. So, we deduce the abnormal stretch reflex is made a modification by affecting the spinal cord, not only the injected muscle is relaxed, but also motor function is improved. Botulinum toxin type A shows sustained activity up to only 3 months, so we think we should use sufficient dose of botulinum toxin which may cause weakness. Rehabilitation with injected muscles contractions is important soon after botulinum toxin treatment, because botulinum toxin has a specific affinity to cleave certain proteins involved in the mechanism of acetylcholine exocytosis. The new botuslinum toxins type A which decrease the risk of production of antibodies and diffusion of noninjected muscles are under development.