Yoshiyuki Mitsui

Mutations in the gene encoding p62 in Japanese patients with amyotrophic lateral sclerosis

Objective: The purpose of this study was to find mutations in the SQSTM1 gene encoding p62 in Japanese patients with amyotrophic lateral sclerosis (ALS), since this gene has been recently identified as a causative gene for familial and sporadic ALS in the United States. Methods: We sequenced this gene in 61 Japanese patients with sporadic and familial ALS. To our knowledge, we describe for the first time the clinical information of such mutation-positive patients. Results: We found novel mutations, p.Ala53Thr and p.Pro439Leu, in 2 patients with sporadic ALS. The clinical picture of the mutation-positive patients was that of typical ALS with varied upper motor neuron signs. Although this gene is causative for another disease, Paget disease of bone (PDB), none of our patients showed evidence of concomitant PDB. Conclusion: The presence of mutations in this racial population suggests worldwide, common involvement of the SQSTM1 gene in ALS.

Altered vasoreactivity to angiotensin II in experimental diabetic neuropathy: role of nitric oxide.

We evaluated the effects of angiotensin II and an angiotensin‐converting enzyme inhibitor (cilazapril) on nerve blood flow (NBF) and electrophysiology in control and diabetic rats. When applied locally to the sciatic nerve, the dose–response curve of angiotensin II was more potent in experimental diabetic neuropathy (EDN) than control rats. No difference existed in plasma angiotensin II levels between EDN and controls. The rats were given typical rat pellets or pellets treated with 10 mg/kg per day cilazapril for 4 weeks. Diabetes caused a significant reduction in NBF, nerve conduction velocity, and compound muscle action potential (CMAP) amplitudes. NBF was significantly increased in diabetic rats supplemented with cilazapril diet, and nerve conduction velocity and amplitudes of the CMAP were also improved after 4 weeks on this diet. Direct application 10−3 mol/L cilazapril on sciatic nerve did not increase NBF in normal and EDN rats. We topically applied the nitric oxide synthase (NOS) inhibitor, NG‐nitro‐L‐arginine, on sciatic nerve and observed reduced inhibition of NBF in EDN, which was correctable with a cilazapril diet. These results suggest that diabetic neuropathy may have an increasing vasopressor action with angiotensin II and this is likely to be the mechanism of NOS inhibition. Angiotensin II‐converting enzyme inhibitors may have potential in the treatment of diabetic neuropathy.

Sensorimotor polyneuropathy associated with chronic lymphocytic leukemia, IgM antigangliosides antibody and human T-cell leukemia virus I infection.

A 65‐year‐old man presented with a sensorimotor polyneuropathy associated with B‐cell chronic lymphocytic leukemia (CLL) and immunoglobulin M (IgM) antibody to various gangliosides. Electrophysiological studies denoted significant abnormalities of motor and sensory nerve conduction. Although the pathology of sural nerve biopsy looked minimally affected, immunohistochemical studies showed specific binding of IgM to the human peripheral nerve. Our patient also had high titer of antibody to human T‐cell leukemia virus I (HTLV‐I) in both serum and cerebrospinal fluid (CSF), which might activate B‐cell–mediated immunity and facilitate the production of IgM antibody. The other unique feature is the reactivity of antibody to gangliosides. The patient had IgM antibody reactivities to gangliosides with disialosyl residue such as GT1b, GQ1b and GD3, but not to GD1b. IgM antibody to gangliosides with disialosyl residue has been reported in ataxic symptoms, but our patient failed to demonstrate ataxia. Without reactivity to GD1b, sensory ataxic neuropathy might not develop even in the presence of antibody reactive to other gangliosides with disialosyl residue.

VCP gene analyses in Japanese patients with sporadic amyotrophic lateral sclerosis identify a new mutation

Accumulating evidence has proven that mutations in the VCP gene encoding valosin-containing protein (VCP) cause inclusion body myopathy with Paget disease of the bone and frontotemporal dementia. This gene was later found to be causative for amyotrophic lateral sclerosis (ALS), a fatal neurodegenerative disease, occurring typically in elderly persons. We thus sequenced the VCP gene in 75 Japanese patients with sporadic ALS negative for mutations in other genes causative for ALS and found a novel mutation, p.Arg487His, in 1 patient. The newly identified mutant as well as known mutants rendered neuronal cells susceptible to oxidative stress. The presence of the mutation in the Japanese population extends the geographic region for involvement of the VCP gene in sporadic ALS to East Asia.

Magnetic resonance imaging and brain-stem auditory evoked potentials in neuro-Behcet's disease

We studied central nervous system lesions in patients with neuro-Behcets disease using magnetic resonance imaging (MRI) of the brain and recording of brain-stem auditory evoked potentials (BAEPs). MRI revealed abnormal findings in seven of eight patients. MRI studies demonstrated extensive regions with high intensity signal in the brain stem and/or basal ganglia on T2-weighted images obtained during the acute stage of the disease in three patients. One of these patients had a strongly gadolinum-enhanced round lesion in the lower pons. In four of the other five patients with chronic disease, brain-stem atrophy was observed on T1-weighted images. Atrophic changes were more severe in the brain stem than in the cerebellum. Abnormal BAEPs were observed in three patients and consisted of prolongation of interpeak latency of waves III-V and defects of wave III or V. Abnormal BAEPs were recorded in patients with severe inflammatory changes or progression of atrophic changes in the brain stem. Our findings show that MRI and BAEPs are useful in detecting the presence and assessing the degree of neurological involvement in patients with neuro-Behcets disease.

A multicentre prospective study of Guillain-Barré Syndrome in Japan: a focus on the incidence of subtypes

Objective Guillain–Barré Syndrome (GBS) is classified into the two major subtypes; acute inflammatory demyelinating polyneuropathy (AIDP) and acute motor axonal neuropathy (AMAN). Previous studies have suggested that AIDP is predominant and AMAN is rare in Western countries, whereas AMAN is not always uncommon in East Asia. We aimed to clarify the incidence of the subtypes of GBS in Japan. Methods We performed a prospective multicentre survey over 3u2005years (2007–2010). Clinical and electrophysiological findings were collected from 184 patients with GBS in 23 tertiary neurology institutes. Anti-ganglioside antibodies were measured by ELISA. We also surveyed the incidence of Fisher syndrome (FS). Results By electrodiagnostic criteria of Ho et al, patients were classified as having AIDP (40%), or AMAN (22%), or unclassified (38%). Anti-GM1 IgG antibodies were found for 47% of AMAN patients, and 18% of AIDP patients (p<0.001). There were no specific regional trends of the electrodiagnosis and anti-GM1 positivity. During the same study period, 79 patients with FS were identified; the percentage of FS cases out of all cases (FS/(GBS+FS)) was 26%. Conclusions The frequency of GBS patients with the electrodiagnosis of AMAN by single nerve conduction studies is approximately 20% in Japan, and the AMAN pattern is closely associated with anti-GM1 antibodies. The incidence of FS appears to be much higher in Japan than in Western countries.

Effect of zenarestat, an aldose reductase inhibitor, on endoneurial blood flow in experimental diabetic neuropathy of rat

The effects of zenarestat, an aldose reductase inhibitor, on endoneurial blood flow (NBF) were explored in streptozotocin-induced diabetic rats. Rats were maintained on a diet of containing 0.09% zenarestat for 8 weeks, then NBF in the sciatic nerve was measured using microelectrode hydrogen polarography. NBF in the diabetic control rats was significantly lower than values in age-matched control rats, however, NBF was not significantly altered in diabetic rats treated with zenarestat. Direct application of nitric oxide synthase inhibitor, NG-nitro-L-arginine, did not affect NBF in diabetic control rats, whereas this application significantly reduced NBF both in age-matched control and zenarestat treated diabetic rats. Considerable levels of zenarestat were confirmed in the sciatic nerve in the drug treated rats. These data suggest that aldose reductase, such as zenarestat, might restore or prevent the alteration of endoneurial blood flow resulting from an impairment of nitric oxide function.

Safety and efficacy of thalidomide in patients with POEMS syndrome: a multicentre, randomised, double-blind, placebo-controlled trial

BACKGROUNDnPolyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome is a rare cause of demyelinating neuropathy, with multi-organ involvement characterised by plasma cell dyscrasia and VEGF overproduction. No treatments have been established for patients with POEMS syndrome who are not eligible for stem-cell transplantation. Thalidomide suppresses VEGF and plasma cell proliferation. We aimed to assess the safety and efficacy of thalidomide for the treatment of POEMS syndrome.nnnMETHODSnWe did a randomised, double-blind, placebo-controlled, phase 2/3 trial at 12 hospitals in Japan. Adults (age ≥20 years) with POEMS syndrome who were ineligible for autotransplantation were randomly assigned (1:1) by a minimisation method to treatment with oral dexamethasone (12 mg/m(2) per day on the first 4 days of every 28-day cycle) plus either oral thalidomide (200 mg daily) or placebo for six cycles. All study personnel and patients were masked to treatment allocation. The primary endpoint was the reduction rate of serum VEGF concentrations at 24 weeks. Analysis was by intention to treat. This study is registered with the UMIN Clinical Trials Registry, UMIN000004179.nnnFINDINGSnBetween Nov 11, 2010, and July 3, 2014, we randomly assigned 25 patients to receive either thalidomide (n=13) or placebo (n=12); one patient in the placebo group was excluded from analyses because of a protocol violation. The adjusted mean VEGF concentration reduction rate at 24 weeks was 0·39 (SD 0·34) in the thalidomide group compared with -0·02 (0·54) in the placebo group (adjusted mean difference 0·41, 95% CI 0·02-0·80; p=0·04). Mild sinus bradycardia was more frequent in the thalidomide group than in the placebo group (seven [54%] vs zero; p=0·006). Five patients had serious adverse events: three in the thalidomide group (transient cardiac arrest, heart failure, and dehydration) and two in the placebo group (ileus and fever). No deaths occurred during the randomised study. In the 48-week open-label study period (n=22), newly developed adverse events were sinus bradycardia (n=4), constipation (n=5), and mild sensory neuropathy (n=5). Two patients died in the open-label study; both patients were initially in the placebo group, and the cause of death was progression of the disease.nnnINTERPRETATIONnThalidomide reduces serum VEGF concentrations and represents a new treatment for patients with POEMS syndrome who are not eligible for stem-cell transplantation. Thalidomide treatment poses a risk of bradycardia; however, the benefits are likely to exceed the risk.nnnFUNDINGnJapanese Ministry of Health, Labour, and Welfare, and Fujimoto Pharmaceuticals.

A small dose of the immunosuppressive agent FK506 (tacrolimus) protects peripheral nerve from ischemic fiber degeneration

The immunosuppressant agent FK506 (tacrolimus) has proven to be neuroprotective against brain ischemia, but there are no data on potential neuroprotective effects of FK506 in peripheral nerve ischemia. We examined the potential effects of two doses of FK506 in protecting peripheral nerve from ischemic fiber degeneration. Ischemia in the left sciatic nerve of the rat was produced by injecting 2 × 106 microspheres (14 μm) into the left femoral, hypogastric, and superior gluteal arteries in proportions of 47%, 37%, and 17%, respectively. After embolization, FK506 was injected into the left femoral, hypogastric, and superior gluteal arteries in doses of 9.4, 7.4, and 3.4 μg, respectively, for the high‐dose group and 4.7, 3.7, and 1.7 μg, respectively, for the low‐dose group. The control rats were injected with saline. FK506 treatment resulted in dramatic behavioral improvement in nerve function, in the number of functioning nerve fibers, and in the salvage of a majority of nerve fibers from ischemic fiber degeneration in a dose‐dependent fashion. These results suggest that a small dose of FK506 protects peripheral nerve from ischemic fiber degeneration and that it may have potential in the treatment of ischemic neuropathy.

Aging differentially modifies sensitivity of nerve blood flow to vasocontractile agents (endothelin-1, noradrenaline and angiotensin II) in sciatic nerve

This study examined the influence of the vaso-constricting agents (noradrenaline, endothelin-1 and angiotensin II) in Sprague-Dawley rats aged 2, 6 and 24 months by evaluating epineurial arteriolar vasoreactivity in response to superfused teat agents. Nerve blood flow (NBF) was measured using microelectrode H2 polarography. In 24-month-old rats, NBF was decreased and vascular resistance (VR) was increased compared with 2- and 6-month-old rats. All of the constricting agents reduced NBF in the 2-, 6- and 24-month groups, however, the effects of the constricting agents reduced significantly with age. These results suggest that during aging, there is a decline of vasoconstrictive responses to noradrenaline, endothelin-1 and angiotensin II in peripheral nerve and that these changes may be due to altered function of receptors.