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.

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.

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 (0–0.10) 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.

[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 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.

Trisodium nitriloacetate monohydrate: promoting effect in urinary bladder carcinogenesis in rats treated with N-butyl-N-(4-hydroxybutyl)nitrosamine

The effect of trisodium nitrilotriacetate monohydrate [(Na3NTA X H2O) CAS: 18662-53-8] on development of urinary bladder tumors in rats initiated with N-butyl-N-(4-hydroxybutyl)nitrosamine [(BBN) CAS: 3817-11-6] was studied. Twenty-one male inbred W rats 6 weeks of age were given drinking water containing 500 ppm of BBN for 4 weeks and then put on diet containing 10,000 ppm of Na3NTA X H2O for 28 weeks. Na3NTA X H2O promoted the development of urinary bladder tumors in rats treated with BBN. The incidences of papilloma and transitional cell carcinomas in the urinary bladder were 90% (18/20) and 25% (4/20), respectively, in rats treated with BBN and then Na3NTA X H2O and 0 in those treated with BBN or Na3NTA X H2O alone. The incidence of papillary or nodular hyperplasia in week 32 was 100% (20/20) in rats treated with BBN and then Na3NTA X H2O and 61% (13/21) in rats treated with BBN only.

Effect of propylthiouracil on the thyroid tumorigenesis induced by N-bis(2-hydroxypropyl)nitrosamine in rats

The effect of 0.15% propylthiouracil (PTU) on thyroid tumorigenesis was studied in male Wistar rats given a single i.p. injection of 280 mg of N-bis(-2-hydroxypropyl)nitrosamine (DHPN) per 100 g body weight. The mean weights of the thyroid of rats treated with DHPN followed by PTU and with PTU alone were significantly higher than those of rats treated with DHPN only and control rats. The incidences of follicular adenoma at the end of week 20 of the experiment were 100% (21/21) in rats treated with DHPN followed by PTU, and 19% (4/21) in rats given DHPN alone. Papillary adenoma was observed in one rat treated with DHPN followed by PTU. The incidence of follicular carcinomas with invasive growth into the capsule, adipose tissues or blood vessels was 52% (11/21) in rats given DHPN and then PTU. No papillary carcinomas or solid tumors were found in any rats. Rats given PTU alone and untreated rats had no thyroid tumors. The serum concentration of T4 in rats treated with PTU alone was significantly lower than that in the control group. The serum concentration of T4 in rats treated with DHPN followed by PTU was slightly, but not significantly, lower than that in control rats. The serum concentrations of T3 in rats treated with DHPN followed by PTU, DHPN alone and PTU alone were also slightly, but not significantly, lower than that in controls.

Trisodium nitrilotriacetate monohydrate: promoting effects on the development of renal tubular cell tumors in rats treated with N-ethyl-N-hydroxyethylnitrosamine

The effect of trisodium nitrilotriacetate monohydrate [N,N-bis(carboxymethyl)glycine trisodium salt] (Na3NTA X H2O) on development of renal tubular cell tumors induced with N-ethyl-N-hydroxyethylnitrosamine [CAS:13147-25-6; 2-(ethylnitrosamino)-ethanol] (EHEN) was studied. Six-week-old male inbred W rats were given a diet containing 1,000 ppm of EHEN for 2 weeks and then a diet containing a high (10,000 ppm) or low (500 ppm) concentration of Na3NTA X H2O for 30 weeks. The rats were killed during week 32. The higher concentration of Na3NTA X H2O enhanced the development of renal tubular cell tumors and increased the number and size of tumors in rats treated with EHEN, but the lower concentration of Na3NTA X H2O did not. The incidence of renal tubular cell tumors in week 32 was 33% in rats treated with 1,000 ppm EHEN for 2 weeks, 100% in rats treated with 1,000 ppm EHEN for 2 weeks plus high Na3NTA X H2O diet for 30 weeks, and 39% in rats treated with 1,000 ppm EHEN for 2 weeks and then given low Na3NTA X H2O diet for 30 weeks. Numbers of atypical cell foci per kidney area (No./cm2) were 17.0 +/- 7.6 in rats treated with EHEN and high Na3NTA X H2O, 7.3 +/- 2.2 in rats treated with EHEN and low Na3NTA X H2O, 3.7 +/- 1.4 in rats treated with EHEN alone, and 1.0 +/- 2.4 in rats treated with high Na3NTA X H2O diet alone. Atypical cell foci retained a tubular pattern and consisted of basophilic cells with a large nucleus or clear cells with a small nucleus.

Basic lead acetate: promoting effect on the development of renal tubular cell tumors in rats treated with N-ethyl-N-hydroxyethylnitrosamine

The development of renal tubular cell tumors by the end of experimental week 32 was studied in inbred Wistar male rats fed a diet containing 1,000 or 500 ppm N-ethyl-N-hydroxyethylnitrosamine (EHEN) for 2 weeks and then given 1,00 ppm basic lead acetate (LA) for 20 weeks. A low dose of LA enhanced the development of renal tubular cell tumors in rats treated with EHEN and increased the number and size of the tumors. The incidence of renal tubular cell tumors at the end of week 32 was 50% in rats treated with 1,000 ppm EHEN for 2 weeks and 100% in rats treated with 1,000 ppm EHEN for 2 weeks and then given 1,000 ppm LA for 20 weeks. The incidences of renal tumors of more than 3 mm in diameter were 70% in rats treated with 1,000 ppm EHEN plus LA and 0% in rats treated with EHEN or LA alone. The low dose of LA showed the enhancing effect of the development of renal tubular cell tumors in rats treated with a subthreshold dose of 500 ppm EHEN.

Promoting effects of phenobarbital and barbital on development of thyroid tumors in rats treated with N-bis(2-hydroxypropyl)nitrosamine

Phenobarbital (PB) and barbital (BB) promoted the development of thyroid tumors in rats treated with a sub-effective dose of N-bis(2-hydroxypropyl)nitrosamine (DHPN) for thyroid tumorigenesis. Rats were given s.c. injections of 70 mg DHPN/100 g body weight once a week for 4 or 6 weeks with or without diet containing 500 p.p.m. PB or BB for the next 12 weeks. The incidences of thyroid tumors at the end of week 20 of the experiment were 66% in rats given DHPN for 4 weeks and then PB, 23% in rats given DHPN for 4 weeks and then BB, 100% in rats given DHPN for 6 weeks and then PB, 45% in rats given DHPN for 6 weeks and then BB, and 23% in rats given DHPN for 6 weeks. Rats given only DHPN for 4 weeks or only PB or BB had no thyroid tumors after 20 weeks.