Charcot-Marie-Tooth disease type 2A with an autosomal-recessive inheritance: the first report of an adult-onset disease.

Axonal Charcot-Marie-Tooth disease (CMT) is most frequently caused by mutations in the MFN2 gene (CMT2A) that can lead to various clinical phenotypes. The age at disease onset varies, but most cases occur before adolescence. We report two Japanese sisters who presented with middle-age-onset peripheral neuropathy with distinct clinical features. In the affected sisters, a homozygous missense mutation, c.1894C>T, p.R632W, corresponding to the transmembrane domain of MFN2 was identified; this mutation was heterozygous in another non-affected sibling, demonstrating co-segregation of the genotype and phenotype. The patients developed adult-onset slowly progressive muscle weakness that was predominant in the calf muscles and sensory disturbance. Magnetic resonance imaging revealed diffuse atrophy of the spinal cord, especially in the thoracic segment, and mild atrophy of the parietal lobe and the cerebellum in both patients. Electron microscopy of the sural nerve revealed clusters of round and swollen mitochondria. This is the first case report of adult-onset CMT2A with an autosomal-recessive inheritance pattern. The phenotype caused by the MFN2 mutation in these cases is very mild, considering that the mutation causes middle-aged-onset Charcot-Marie-Tooth even in the homozygous state. The mechanism of MFN2 mutation-induced toxicity is an interesting theme that awaits further investigations.

Stem cell factor-activated bone marrow ameliorates amyotrophic lateral sclerosis by promoting protective microglial migration.

Amyotrophic lateral sclerosis (ALS) is a progressive disease associated with motor neuron death. Several experimental treatments, including cell therapy using hematopoietic or neuronal stem cells, have been tested in ALS animal models, but therapeutic benefits have been modest. Here we used a new therapeutic strategy, bone marrow transplantation (BMT) with stem cell factor (SCF)- or FMS-like tyrosine kinase 3 (flt3)-activated bone marrow (BM) cells for the treatment of hSOD1(G93A) transgenic mice. Motor function and survival showed greater improvement in the SCF group than in the group receiving BM cells that had not been activated (BMT alone group), although no improvement was shown in the flt3 group. In addition, larger numbers of BM-derived cells that expressed the microglia marker Iba1 migrated to the spinal cords of recipient mice compared with the BMT alone group. Moreover, after SCF activation, but not flt3 activation or no activation, the migrating microglia expressed glutamate transporter-1 (GLT-1). In spinal cords in the SCF group, inflammatory cytokines tumor necrosis factor-α and interleukin-1ß were suppressed and the neuroprotective molecule insulin-like growth factor-1 increased relative to nontreatment hSOD1(G93A) transgenic mice. Therefore, SCF activation changed the character of the migrating donor BM cells, which resulted in neuroprotective effects. These studies have identified SCF-activated BM cells as a potential new therapeutic agent for the treatment of ALS.

Inactivation of TNF-α ameliorates diabetic neuropathy in mice.

Tumor necrosis factor (TNF)-α is a potent proinflammatory cytokine involved in the pathogenesis of diabetic neuropathy. We inactivated TNF-α to determine if it is a valid therapeutic target for the treatment of diabetic neuropathy. We effected the inactivation in diabetic neuropathy using two approaches: by genetic inactivation of TNF-α (TNF-α(-/-) mice) or by neutralization of TNF-α protein using the monoclonal antibody infliximab. We induced diabetes using streptozotocin in wild-type and TNF-α(-/-) mice. We measured serum TNF-α concentration and the level of TNF-α mRNA in the dorsal root ganglion (DRG) and evaluated nerve function by a combination of motor (MNCV) and sensory (SNCV) nerve conduction velocities and tail flick test, as well as cytological analysis of intraepidermal nerve fiber density (IENFD) and immunostaining of DRG for NF-κB p65 serine-276 phosphorylated and cleaved caspase-3. Compared with nondiabetic mice, TNF-α(+/+) diabetic mice displayed significant impairments of MNCV, SNCV, tail flick test, and IENFD as well as increased expression of NF-κB p65 and cleaved caspase-3 in their DRG. In contrast, although nondiabetic TNF-α(-/-) mice showed mild abnormalities of IENFD under basal conditions, diabetic TNF-α(-/-) mice showed no evidence of abnormal nerve function tests compared with nondiabetic mice. A single injection of infliximab in diabetic TNF-α(+/+) mice led to suppression of the increased serum TNF-α and amelioration of the electrophysiological and biochemical deficits for at least 4 wk. Moreover, the increased TNF-α mRNA expression in diabetic DRG was also attenuated by infliximab, suggesting infliximab's effects may involve the local suppression of TNF-α. Infliximab, an agent currently in clinical use, is effective in targeting TNF-α action and expression and amelioration of diabetic neuropathy in mice.

[Case of minocycline-induced vasculitic neuropathy].

A 70-year-old woman was admitted to our hospital because of fever, numbness in her extremities and right drop foot. Because her hip prosthesis had loosened as a result of infection, she had been taking 100 mg of minocycline orally for eight months. Three months before admission, she had had melena several times and body weight loss and pyrexia developed. A month before admission, asymmetrical paresthesia and numbness appeared in her extremities and finally right drop foot developed. Laboratory tests showed elevated C-reactive protein and positive anti-nuclear antibody. Abnormalities found in nerve conduction study were compatible with mononeuritis multiplex. Sural nerve biopsy revealed an occluded medium-size artery in the epineurium and axonal degeneration in the nerve fascicles, confirming the diagnosis of vasculitic neuropathy. These manifestations met the American Congress Rheumatology criteria for polyarteritis nodosa. However, her clinical conditions markedly improved after discontinuing minocycline and therefore she was diagnosed as having minocycline-induced vasculitic neuropathy. Although minocycline-induced vasculitis is a well known adverse effect of the drug, peripheral neuropathy with biopsy findings has rarely been reported. Drug induced-vasculitis is important as a differential diagnosis for mononeuritis multiplex because the symptoms can be improved by the discontinuation of an offending drug.

[A case of agrammatism due to cerebral infarction of the middle-lower part of the right precentral gyrus].

A right-handed 75-year-old man was admitted to our hospital complaining of sudden speech difficulty. Neurological examination showed slight left facial palsy of central origin. Although his spontaneous speech was fluent and contained no phonological or verbal paraphasia, it was like telegraphic speech, omitting or misusing postpositional particles. There was no history of changing handedness or family history of sinistrality or ambidexterity. Brain magnetic resonance imaging revealed fresh infarction of the middle-lower part of the right precentral gyrus. The WAIS-R VIQ, PIQ, and total IQ scores were 108, 100, and 117, respectively. In the explanation of a four-frame comic strip of the SLTA, there were misuses of postpositional particles in both speaking and writing. There was about 10% misuse on 249 questions for inserting postpositional particles in sentences. He had difficulty in changing from active- to passive-voice sentences and vice versa. In this patient, the lesion of the middle-lower part of the right precentral gyrus might be important for the expression of agrammatism in crossed aphasia.

[Subacute myopathy in a patient with mild Cushing disease manifested by accompanying Kleinfelter syndrome].

A 69-year-old man was admitted because of subacute development of lower limb weakness from one month ago. He showed central obesity, gynecomastia, dorsal fat pad ("buffalo hump"), and proximal muscle weakness in the lower extremities (manual muscle test 4). Needle EMG, muscle MRI and labolatry screening including CPK were negative for neuromuscular diseases, except for the hypogenitalism accidentally detected in MRI. Although blood corticol was in normal range, the levels of serum ACTH and 24-hour urinary free cortisol excretion were high, and the dexamethasone suppression tests were positive. Brain MRI showed a small pituitary mass with gadolinium enhancement, and ACTH measurement from petrosal sinus sampling after CRH stimulation lead to the diagnosis of definite Cushing disease. Moreover, he also showed low testosterone and elevated LH and FSH. Chromosome banding revealed 47 XXY in 22 in 30 cells, leading to the diagnosis of mosaic Klinefelter syndrome. The supplementation with testosterone was partially effective for his weakness. The surgical resection of pituitary microadenoma resulted in the full recovery. Either Klinefelter syndrome or mild Cushing disease alone was insufficient as a cause of the muscle weakness in this patient. It is plausible that the mild elevation of cortisol accompanied by the lack of tesstelone may underlie the weakness, probably linked to impaired balance between muscle anabolism and catabolism.

Rationale and usefulness of newly devised abbreviated diagnostic criteria and staging for diabetic polyneuropathy.

In order to establish a diagnostic criteria for diabetic polyneuropathy (DP) for daily practice, usefulness of the abbreviated diagnostic criteria proposed by Diabetic Neuropathy Study Group in Japan was examined in 131 diabetic patients in admission and outpatient clinic. The prerequisite condition includes: (1) diagnosed as diabetes and (2) other neuropathies than diabetic neuropathy can be excluded. The criteria should meet any of the following three items: (1) sensory symptoms considered to be due to DP, (2) bilaterally decreased or absent ankle reflex and (3) decreased vibratory sensation in bilateral medial malleoli. Using this criteria, sensitivity (68%) and specificity (74%) were obtained by evaluating nerve conduction study as gold standard, suggesting usefulness of the criteria for diagnosis of DP especially for daily practice. Staging of DP is now sought to establish the consensus for the specific therapy for its stage. Thirty-one diabetic patients in admission was evaluated to examine usefulness of the newly devised staging system of DP. Staging was almost consistent between the new staging system and Dyck's staging (gold standard) and nerve function deteriorated with increasing stage, suggesting that usefulness and rationale of this staging system is well substantiated.

Hereditary motor and sensory neuropathy (proximal dominant form, HMSN-P) among Brazilians of Japanese ancestry.

Hereditary motor and sensory neuropathy (proximal dominant form, HMSN-P) has been reported exclusively from Okinawa Prefecture in Japan. We herein report three brothers with HMSN-P who are among Brazilians of Japanese ancestry. They showed the typical clinical manifestations and were compatible with HMSN-P. Okinawa Prefecture has been a site of emigration to other countries, mainly in South America, since 1908. Although this is the first reported familial case of HMSN-P occurring outside Japan, it is estimated that there are 19 or 20 individuals with HMSN-P among these emigrants. Since HMSN-P might be misdiagnosed as familial amyotrophic lateral sclerosis or spinal muscular atrophy, neurologists in countries where individuals of Okinawan extraction reside should be aware of this hereditary neuropathy. HMSN-P should no longer be regarded as an endemic condition limited to Okinawa.

Cytomegalovirus-induced small-bowel hemorrhage in a patient with nonsystemic vasculitic neuropathy.

A 73-year-old man who was being treated with corticosteroids for nonsystemic vasculitic neuropathy developed small-bowel hemorrhage after ileostomy for ileus. Immunohistochemical staining for cytomegalovirus (CMV) antigen in the ulcer in the resected ileum was positive; thus, cytomegalovirus infection of the small intestine caused his gastrointestinal manifestations. Cytomegalovirus infection should be considered in the differential diagnosis of gastrointestinal diseases in patients with collagen vascular diseases receiving immunosuppressive agents.

Clinical Phenotype and Segregation of Mitochondrial 3243A>G Mutation in 2 Pairs of Monozygotic Twins.

IMPORTANCE: The regulatory factors explaining the wide spectrum of clinical phenotypes for mitochondrial 3243A>G mutation are not known. Crosstalk between nuclear genes and mitochondrial DNA might be one factor. OBSERVATIONS: In this case series, we compared 2 pairs of male twins with the mitochondrial 3243 A>G mutation and mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes syndrome with a female control patient. One pair of monozygotic twins presented with diabetes and deafness in their 30s, stroke-like episodes in their 40s, and cardiac events and death in their 50s. Another pair of twins presented with deafness and stroke-like episodes in their 20s. The degree of heteroplasmy of 3243A>G mutation in the various tissues and organs was similar in the first pair of twins compared with the control patient. CONCLUSIONS AND RELEVANCE: The clinical phenotype and segregation of mitochondrial 3243A>G mutation was similar in monozygotic twins. The onset age and distribution of the symptoms might be regulated by nuclear genes. Our findings might help to predict the clinical course of the surviving twins and afford an opportunity for therapy before the onset of mitochondrial disease, especially for monozygotic twins caused by nuclear transfer with a small amount of nuclear-donor mitochondrial DNA.

Antiganglion neuron antibodies correlate with neuropathy in Sjögren's syndrome.

To investigate the possible implication of antibodies against dorsal root ganglion neuron in the pathogenesis of sensory neuropathy with Sjögren's syndrome, we examined the pathogenic role of antiganglion neuron antibodies by immunoblotting, immunohistochemistry and immunoreactive assay. Sjögren's syndrome patients without neuropathy, patients with vasculitic neuropathy and normal volunteers were evaluated as controls. Antiganglion neuron antibodies recognizing certain proteins of several different molecular weights were detected only in patients of sensory neuropathy with Sjögren's syndrome. Those antibodies labeled specific-sized neurons in the fixed ganglion and isolated ganglion neurons under the culture condition, each of which corresponded well to clinical manifestations. These results suggest that antiganglion neuron antibodies may contribute to the pathogenesis of sensory neuropathy with Sjögren's syndrome.

[A case of stroke-like episode of MELAS of which progressive spread would be prevented by edaravone].

A thirty-two-year-old woman who had been diagnosed MELAS with 3243A > G mutation presented headache, nausea, decreased bilateral visual acuity, and topographical disturbance on January 1 in 2002. Although brain CT showed no fresh lesion, recurrence of stroke-like episode was considered. Immediately, she was treated with ubiquinone (210 mg/day, p.o.) and tocopherol nicotinate (300 mg/day, p.o.). She became confused on the fifth day. Diffusion weighted- and T2 weighted-MRI revealed appearance of hyperintense lesion at the right occipital lobe. We started edaravone infusion (30 mg, twice a day, div.) for two weeks with informed consent from her family. On 13th day her consciousness was improved. Edema and signal intensity of the lesion were decreased on MRI with minimal spread to the parietal lobe. She discharged on the 30th day with marked visual field loss, hemispatial neglect, and topographical amnesia. MRI after four months showed remarkable atrophy of the right occipital region. In our department, five stroke-like episodes including this case were treated with ubuiquinone and tocopherol nicotinate. This regimen was effective in prevention of progressive spread of lesions only in two episodes. Edaravone is radical scavenger used in acute cerebral infarction. Progressive spread into the neighboring regions is one of characteristics of MELAS, although its precise mechanisms are not well known. Oxidative stress induced by released free radicals through mitochondrial dysfunction might be one of factors and edaravone would make an effect through blockage of the free radicals. Edaravone could not rescue neurons in the initial lesion. Although more numbers of cases are needed to establish the effect of edaravone on MELAS, it could minimize the neurological deficits after stroke-like episode of MELAS.

Urinary Potassium Excretion and Renal and Cardiovascular Complications in Patients with Type 2 Diabetes and Normal Renal Function.

BACKGROUND AND OBJECTIVES: We investigated the association of urinary potassium and sodium excretion with the incidence of renal failure and cardiovascular disease in patients with type 2 diabetes. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: A total of 623 Japanese type 2 diabetic patients with eGFR≥60 ml/min per 1.73 m(2) were enrolled in this observational follow-up study between 1996 and 2003 and followed-up until 2013. At baseline, a 24-hour urine sample was collected to estimate urinary potassium and sodium excretion. The primary end point was renal and cardiovascular events (RRT, myocardial infarction, angina pectoris, stroke, and peripheral vascular disease). The secondary renal end points were the incidence of a 50% decline in eGFR, progression to CKD stage 4 (eGFR<30 ml/min per 1.73 m(2)), and the annual decline rate in eGFR. RESULTS: During the 11-year median follow-up period, 134 primary end points occurred. Higher urinary potassium excretion was associated with lower risk of the primary end point, whereas urinary sodium excretion was not. The adjusted hazard ratios for the primary end point in Cox proportional hazards analysis were 0.56 (95% confidence interval [95% CI], 0.33 to 0.95) in the third quartile of urinary potassium excretion (2.33-2.90 g/d) and 0.33 (95% CI, 0.18 to 0.62) in the fourth quartile (>2.90 g/d) compared with the lowest quartile (<1.72 g/d). Similar associations were observed for the secondary renal end points. The annual decline rate in eGFR in the fourth quartile of urinary potassium excretion (-1.3 ml/min per 1.73 m(2)/y; 95% CI, -1.5 to -1.0) was significantly slower than those in the first quartile (-2.2; 95% CI, -2.4 to -1.8). CONCLUSIONS: Higher urinary potassium excretion was associated with the slower decline of renal function and the lower incidence of cardiovascular complications in type 2 diabetic patients with normal renal function. Interventional trials are necessary to determine whether increasing dietary potassium is beneficial.

SUMO-1 co-localized with mutant atrophin-1 with expanded polyglutamines accelerates intranuclear aggregation and cell death.

To investigate the implication of small ubiquitin-related modifier-1 (SUMO-1) in the formation of neuronal intranuclear inclusions in polyglutamine diseases, we examined the localization of SUMO-1 in dentatorubral-pallidoluysian atrophy (DRPLA) brain tissues and PC12 cells expressing truncated atrophin-1 with expanded poly-glutamine stretches. SUMO-1 was co-localized with neuronal intranuclear inclusions in DRPLA brain and the DRPLA model cells, which showed that the aggregates formed by expanded polyglutamine stretches were highly SUMOlylated. In addition, to examine the role of SUMO-1 in nuclear aggregate formation and cell death, either SUMO-1 or DeltaSUMO-1, which is a SUMOlylation defective mutant lacking the C-terminal motif, was co-transfected with atrophin-1 with expanded polyglutamine stretches. Co-transfection of DeltaSUMO-1 decreased number of the cells with nuclear aggregates and consequent apoptosis of PC12 cells, both of which were markedly enhanced by co-transfection of SUMO-1 with atrophin-1 with expanded polyglutamine stretches. These results suggest that SUMO-1 is implicated in the pathogenesis of DRPLA and accelerates aggregate formation and cell death.

Gene therapy for neuropathic pain by silencing of TNF-α expression with lentiviral vectors targeting the dorsal root ganglion in mice.

Neuropathic pain can be a debilitating condition. Many types of drugs that have been used to treat neuropathic pain have only limited efficacy. Recent studies indicate that pro-inflammatory mediators including tumor necrosis factor α (TNF-α) are involved in the pathogenesis of neuropathic pain. In the present study, we engineered a gene therapy strategy to relieve neuropathic pain by silencing TNF-α expression in the dorsal root ganglion (DRG) using lentiviral vectors expressing TNF short hairpin RNA1-4 (LV-TNF-shRNA1-4) in mice. First, based on its efficacy in silencing TNF-α in vitro, we selected shRNA3 to construct LV-TNF-shRNA3 for in vivo study. We used L5 spinal nerve transection (SNT) mice as a neuropathic pain model. These animals were found to display up-regulated mRNA expression of activating transcription factor 3 (ATF3) and neuropeptide Y (NPY), injury markers, and interleukin (IL)-6, an inflammatory cytokine in the ipsilateral L5 DRG. Injection of LV-TNF-shRNA3 onto the proximal transected site suppressed significantly the mRNA levels of ATF3, NPY and IL-6, reduced mechanical allodynia and neuronal cell death of DRG neurons. These results suggest that lentiviral-mediated silencing of TNF-α in DRG relieves neuropathic pain and reduces neuronal cell death, and may constitute a novel therapeutic option for neuropathic pain.

Predictive properties of plasma amino acid profile for cardiovascular disease in patients with type 2 diabetes.

Prevention of cardiovascular disease (CVD) is an important therapeutic object of diabetes care. This study assessed whether an index based on plasma free amino acid (PFAA) profiles could predict the onset of CVD in diabetic patients. The baseline concentrations of 31 PFAAs were measured with high-performance liquid chromatography-electrospray ionization-mass spectrometry in 385 Japanese patients with type 2 diabetes registered in 2001 for our prospective observational follow-up study. During 10 years of follow-up, 63 patients developed cardiovascular composite endpoints (myocardial infarction, angina pectoris, worsening of heart failure and stroke). Using the PFAA profiles and clinical information, an index (CVD-AI) consisting of six amino acids to predict the onset of any endpoints was retrospectively constructed. CVD-AI levels were significantly higher in patients who did than did not develop CVD. The area under the receiver-operator characteristic curve of CVD-AI (0.72 [95% confidence interval (CI): 0.64-0.79]) showed equal or slightly better discriminatory capacity than urinary albumin excretion rate (0.69 [95% CI: 0.62-0.77]) on predicting endpoints. A multivariate Cox proportional hazards regression analysis showed that the high level of CVD-AI was identified as an independent risk factor for CVD (adjusted hazard ratio: 2.86 [95% CI: 1.57-5.19]). This predictive effect of CVD-AI was observed even in patients with normoalbuminuria, as well as those with albuminuria. In conclusion, these results suggest that CVD-AI based on PFAA profiles is useful for identifying diabetic patients at risk for CVD regardless of the degree of albuminuria, or for improving the discriminative capability by combining it with albuminuria.

Haematopoietic cells produce BDNF and regulate appetite upon migration to the hypothalamus.

Brain-derived neurotrophic factor (BDNF) suppresses food intake by acting on neurons in the hypothalamus. Here we show that BDNF-producing haematopoietic cells control appetite and energy balance by migrating to the hypothalamic paraventricular nucleus. These haematopoietic-derived paraventricular nucleus cells produce microglial markers and make direct contacts with neurons in response to feeding status. Mice with congenital BDNF deficiency, specifically in haematopoietic cells, develop hyperphagia, obesity and insulin resistance. These abnormalities are ameliorated by bone marrow transplantation with wild-type bone marrow cells. Furthermore, when injected into the third ventricle, wild-type bone marrow mononuclear cells home to the paraventricular nucleus and reverse the hyperphagia of BDNF-deficient mice. Our results suggest a novel mechanism of feeding control based on the production of BDNF by haematopoietic cells and highlight a potential new therapeutic route for the treatment of obesity.

4-Hydroxy hexenal derived from docosahexaenoic acid protects endothelial cells via Nrf2 activation.

Recent studies have proposed that n-3 polyunsaturated fatty acids (n-3 PUFAs) have direct antioxidant and anti-inflammatory effects in vascular tissue, explaining their cardioprotective effects. However, the molecular mechanisms are not yet fully understood. We tested whether n-3 PUFAs showed antioxidant activity through the activation of nuclear factor erythroid 2-related factor 2 (Nrf2), a master transcriptional factor for antioxidant genes. C57BL/6 or Nrf2(-/-) mice were fed a fish-oil diet for 3 weeks. Fish-oil diet significantly increased the expression of heme oxygenase-1 (HO-1), and endothelium-dependent vasodilation in the aorta of C57BL/6 mice, but not in the Nrf2(-/-) mice. Furthermore, we observed that 4-hydroxy hexenal (4-HHE), an end-product of n-3 PUFA peroxidation, was significantly increased in the aorta of C57BL/6 mice, accompanied by intra-aortic predominant increase in docosahexaenoic acid (DHA) rather than that in eicosapentaenoic acid (EPA). Human umbilical vein endothelial cells were incubated with DHA or EPA. We found that DHA, but not EPA, markedly increased intracellular 4-HHE, and nuclear expression and DNA binding of Nrf2. Both DHA and 4-HHE also increased the expressions of Nrf2 target genes including HO-1, and the siRNA of Nrf2 abolished these effects. Furthermore, DHA prevented oxidant-induced cellular damage or reactive oxygen species production, and these effects were disappeared by an HO-1 inhibitor or the siRNA of Nrf2. Thus, we found protective effects of DHA through Nrf2 activation in vascular tissue, accompanied by intra-vascular increases in 4-HHE, which may explain the mechanism of the cardioprotective effects of DHA.