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Wide-spread fasciculations are a characteristic feature in amyotrophic lateral sclerosis (ALS), suggesting motor axonal hyperexcitability. Previous excitability studies have shown increased nodal persistent sodium conductances and decreased potassium currents in motor axons of ALS patients, both of the changes inducing hyperexcitability. Altered axonal excitability potentially contributes to motor neuron death in ALS, but the relationship of the extent of motor neuronal death and abnormal excitability has not been fully elucidated. We performed multiple nerve excitability measurements in the median nerve at the wrist of 140 ALS patients and analyzed the relationship of compound muscle action potential (CMAP) amplitude (index of motor neuronal loss) and excitability indices, such as strength-duration time constant, threshold electrotonus, recovery cycle and current-threshold relationships. Compared to age-matched normal controls (n = 44), ALS patients (n = 140) had longer strength-duration time constant (SDTC: a measure of nodal persistent sodium current; p < 0.05), greater threshold changes in depolarizing threshold electrotonus (p < 0.05) and depolarizing current threshold relationship (i.e. less accommodation; (p < 0.05), greater superexcitability (a measure of fast potassium current; p < 0.05) and reduced late subexcitability (a measure of slow potassium current; p < 0.05), suggesting increased persistent sodium currents and decreased potassium currents. The reduced potassium currents were found even in the patient subgroups with normal CMAP (> 5mV). Regression analyses showed that SDTC (R = -0.22) and depolarizing threshold electrotonus (R = -0.22) increased with CMAP decline. These findings suggest that motor nerve hyperexcitability occurs in the early stage of the disease, and precedes motor neuronal loss in ALS. Modulation of altered ion channel function could be a treatment option for ALS.

ObjectiveTo elucidate current epidemiological, clinical profiles, and treatment of polyneuropathy, organomegaly, endocrinopathy, M-protein, and skin changes (POEMS) syndrome.MethodsWe conducted a nationwide survey in 2015 using an established epidemiologic method. Data processing sheets were sent to all neurology and hematology specialist departments throughout Japan to identify patients with POEMS who were seen between April 2012 and March 2015.ResultsThe estimated number of patients with POEMS was 392 (95% confidence interval [CI] 320–464), and the prevalence was 0.3 per 100,000. Detailed clinical profiles were available for 167 patients. Median age at onset was 54 years (range, 21–84 years), and the ratio of male to female was 1.5. All patients showed polyneuropathy; 89% had monoclonal plasma cell proliferation; and 84% had elevated vascular endothelial growth factor level in whom pretreatment serum or plasma was available (n = 87). Other common features were skin changes (84%), edema/effusion (81%), and organomegaly (76%). A total of 160 patients were treated with any of the following: radiation, corticosteroids, melphalan, thalidomide, lenalidomide, bortezomib, or autologous stem cell transplantation. Primary therapeutic options were thalidomide (n = 86) and autologous stem cell transplantation (n = 71). Thirty-nine patients (24%) were initially treated with corticosteroid alone. The 10-year overall survival was 93% (95% CI 86%–96%).DiscussionThis study showed current epidemiologic and clinical status of POEMS syndrome in Japan. A quarter of patients were still inadequately treated with corticosteroid alone, whereas either autologous stem cell transplantation or immunomodulatory drugs improved the prognosis.

ObjectivePOEMS (polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes) syndrome is a rare multisystem disease characterised by plasma cell dyscrasia and overproduction of vascular endothelial growth factor (VEGF). VEGF is assumed to be useful in monitoring disease activity, because VEGF levels usually decrease after treatment. However, there is no study to investigate whether the extent of decrease in VEGF correlates with clinical outcome. We tested the predictive efficacy of serum VEGF levels in POEMS syndrome.MethodThis was an institutional review board approved retrospective observational cohort study of 20 patients with POEMS monitored regularly for more than 12 months (median follow-up, 87 months) after treatment onset using our prospectively accumulated database of POEMS from 1999 to 2015. Patients were treated by autologous peripheral blood stem cell transplantation or thalidomide administration. Serum VEGF was measured by ELISA. Outcome measures included clinical and laboratory findings and relapse-free survival.ResultsSerum VEGF levels decreased rapidly after treatment, and stabilised by 6 months post treatment. Patients with normalised serum VEGF levels (<1040 pg/mL) at 6 months showed prolonged relapse-free survival (HR=12.81, 95% CI 2.691 to 90.96; p=0.0001) and greater later clinical improvement. The rate of serum VEGF reduction over the first 6 months post treatment correlated with increased grip strength, serum albumin levels, and compound muscle action potential amplitudes at 12 months.ConclusionsSerum VEGF level at 6 months post treatment is a predicative biomarker for disease activity and prognosis in POEMS syndrome. Serum VEGF could be used as a surrogate endpoint for relapse-free survival or clinical or laboratory improvement of POEMS syndrome for clinical trials.

ObjectiveTo propose the optimal diagnostic criteria for polyneuropathy, organomegaly, endocrinopathy, M-protein and skin changes (POEMS) syndrome using appropriate statistical methods and disease controls.MethodsThis retrospective cohort study included 104 consecutive patients with suspected POEMS syndrome, among whom a gold standard group of 60 patients with definitive POEMS syndrome diagnosis were followed for at least 12 months to strictly exclude other disorders mimicking POEMS syndrome and to confirm response to POEMS syndrome-specific treatment. Thirty patients with chronic inflammatory demyelinating polyradiculoneuropathy (demyelinating polyradiculoneuropathy controls) and 30 with multiple myeloma or immunoglobulin light chain amyloidosis (monoclonal plasma cell proliferation controls) were also included. Logistic regression analyses were performed to determine optimal combination of clinical and laboratory abnormalities, characteristic of POEMS syndrome.ResultsThe diagnostic criteria were statistically defined as the presence of the three major criteria (polyneuropathy (typically demyelinating), monoclonal plasma cell proliferative disorder and elevated vascular endothelial growth factor) and at least two of the four minor criteria (oedema/effusion, skin changes, organomegaly and sclerotic bone lesions), based on best performance by area under the receiver operating characteristic curve analyses. The sensitivity and specificity were 100% and 100%, respectively; the diagnostic accuracy of the proposed criteria was equivalent to somewhat complicated previous criteria.ConclusionsThe statistically defined, simple diagnostic criteria for POEMS syndrome could accelerate early diagnosis and treatment, thereby contribute to better outcome in patients with this serious disease. Prospective larger studies are required to confirm the validity.