Decreased Peak Expiratory Flow Associated with Muscle Fiber-Type Switching in Spinal and Bulbar Muscular Atrophy

Exercise attenuates polyglutamine-mediated neuromuscular degeneration in a mouse model of spinal and bulbar muscular atrophy

BACKGROUND

Spinal and bulbar muscular atrophy (SBMA) is a hereditary neuromuscular disorder caused by the expansion of trinucleotide cytosine-adenine-guanine (CAG) repeats, which encodes a polyglutamine (polyQ) tract in the androgen receptor (AR) gene. Recent evidence suggests that, in addition to motor neuron degeneration, defective skeletal muscles are also the primary contributors to the pathogenesis in SBMA. While benefits of physical exercise have been suggested in SBMA, underlying mechanism remains elusive.

METHODS

We investigated the effect of running exercise in a transgenic mouse model of SBMA carrying human AR with 97 expanded CAGs (AR97Q). We assigned AR97Q mice to exercise and sedentary control groups, and mice in the exercise group received 1-h forced running wheel (5 m/min) 5 days a week for 4 weeks during the early stage of the disease. Motor function (grip strength and rotarod performance) and survival of each group were analysed, and histopathological and biological features in skeletal muscles and motor neurons were evaluated.

RESULTS

AR97Q mice in the exercise group showed improvement in motor function (~40% and ~50% increase in grip strength and rotarod performance, respectively, P < 0.05) and survival (median survival 23.6 vs. 16.7 weeks, P < 0.05) with amelioration of neuronal and muscular histopathology (~1.4-fold and ~2.8-fold increase in motor neuron and muscle fibre size, respectively, P < 0.001) compared to those in the sedentary group. Nuclear accumulation of polyQ-expanded AR in skeletal muscles and motor neurons was suppressed in the mice with exercise compared to the sedentary mice (~50% and ~30% reduction in 1C2-positive cells in skeletal muscles and motor neurons, respectively, P < 0.05). We found that the exercise activated 5'-adenosine monophosphate-activated protein kinase (AMPK) signalling and inhibited mammalian target of rapamycin pathway that regulates protein synthesis in skeletal muscles of SBMA mice. Pharmacological activation of AMPK inhibited protein synthesis and reduced polyQ-expanded AR proteins in C2C12 muscle cells.

CONCLUSIONS

Our findings suggest the therapeutic potential of exercise-induced effect via AMPK activation in SBMA.

Simple and efficient differentiation of human iPSCs into contractible skeletal muscles for muscular disease modeling

Pathophysiological analysis and drug discovery targeting human diseases require disease models that suitably recapitulate patient pathology. Disease-specific human induced pluripotent stem cells (hiPSCs) differentiated into affected cell types can potentially recapitulate disease pathology more accurately than existing disease models. Such successful modeling of muscular diseases requires efficient differentiation of hiPSCs into skeletal muscles. hiPSCs transduced with doxycycline-inducible MYOD1 (MYOD1-hiPSCs) have been widely used; however, they require time- and labor-consuming clonal selection, and clonal variations must be overcome. Moreover, their functionality should be carefully examined. Here, we demonstrated that bulk MYOD1-hiPSCs established with puromycin selection rather than G418 selection showed rapid and highly efficient differentiation. Interestingly, bulk MYOD1-hiPSCs exhibited average differentiation properties of clonally established MYOD1-hiPSCs, suggesting that it is possible to minimize clonal variations. Moreover, disease-specific hiPSCs of spinal bulbar muscular atrophy (SBMA) could be efficiently differentiated via this method into skeletal muscle that showed disease phenotypes, suggesting the applicability of this method for disease analysis. Finally, three-dimensional muscle tissues were fabricated from bulk MYOD1-hiPSCs, which exhibited contractile force upon electrical stimulation, indicating their functionality. Thus, our bulk differentiation requires less time and labor than existing methods, efficiently generates contractible skeletal muscles, and may facilitate the generation of muscular disease models.

Daytime napping, comorbidity profiles, and the risk of sarcopenia in older individuals

Appropriate daytime napping is associated with the decreased risk of cerebro-cardiovascular diseases, but whether daytime napping affects sarcopenia remains to be explored. Our study plans to examine the associations between sarcopenia with daytime napping and comorbidity. The study population came from the China Health and Retirement Longitudinal Study 2011-2015. Latent class analysis (LCA) was used to identify comorbidity profiles based on 14 doctor-diagnosed chronic diseases. Subsequently, smooth function and restricted cubic spline with three binomial regression models determined the associations between sarcopenia with daytime napping and comorbidity profiles. About 18.7% (2,894) and 5.4% (832) of 15,404 individuals were diagnosed with sarcopenia and severe sarcopenia. LCA delineated four classes as the best fit as follows: dominant heart diseases or risks (class 1, N = 2,203), dominant chronic lung diseases (class 2, N = 740), minimal or least diseases (class 3, N = 10,612, reference), and dominant digestive diseases and rheumatism (class 4, N = 1849). Compared with the reference group (class 3), the multivariate-adjusted ORs (95% CIs) of sarcopenia in model 3 were 0.72 (0.60-0.88) for class 1, 1.17 (0.92-1.51) for class 2, and 0.92 (0.77-1.09) for class 4. Smooth function and restricted cubic spline suggested that individuals who napped about 60 min seemingly had the lowest risk of sarcopenia. Individuals who napped for 1-59 min (adjusted OR = 0.80, 95% CI: 0.68-0.94) and 60-119 min (adjusted OR = 0.83, 95% CI: 0.72-0.95) had the significantly lower risk of sarcopenia but not severe sarcopenia than those who did not nap. Insufficient and excessive daytime napping might be associated with the increased risk of sarcopenia, especially in individuals with a dominant chronic lung disease profile.

Development of a functional composite for the evaluation of spinal and bulbar muscular atrophy

This study aimed to develop a functional measurement that combines quantitative motor evaluation index of various body regions in patients with spinal and bulbar muscular atrophy (SBMA). We assessed subjects with SBMA and healthy controls with quantitative muscle strength measurements and functional scales. We selected tongue pressure, grip power, % peak expiratory flow (%PEF), timed walking test, and % forced vital capacity (%FVC) as components. By combining these values with Z-score, we created a functional composite (SBMA functional composite: SBMAFC). We also calculated the standardized response mean to compare the sensitivity of SBMAFC with that of existing measurements. A total of 97 genetically confirmed patients with SBMA and 36 age- and sex-matched healthy controls were enrolled. In the longitudinal analysis, the standardized response mean of SBMAFC was larger than that of existing rating scales. Receiver operating characteristic (ROC) analysis demonstrated that the SBMAFC is capable of distinguishing between subjects with early-stage SBMA and healthy controls. SBMAFC is more sensitive to disease progression than existing functional rating scales and is a potential outcome measure in clinical trials of SBMA.

Neuromuscular junction pathology is correlated with differential motor unit vulnerability in spinal and bulbar muscular atrophy

Spinal and bulbar muscular atrophy (SBMA) is an X-linked, neuromuscular neurodegenerative disease for which there is no cure. The disease is characterized by a selective decrease in fast-muscle power (e.g., tongue pressure, grip strength) accompanied by a selective loss of fast-twitch muscle fibers. However, the relationship between neuromuscular junction (NMJ) pathology and fast-twitch motor unit vulnerability has yet to be explored. In this study, we used a cross-model comparison of two mouse models of SBMA to evaluate neuromuscular junction pathology, glycolytic-to-oxidative fiber-type switching, and cytoskeletal alterations in pre- and postsynaptic termini of tibialis anterior (TA), gastrocnemius, and soleus hindlimb muscles. We observed significantly increased NMJ and myofiber pathology in fast-twitch, glycolytic motor units of the TA and gastrocnemius compared to slow-twitch, oxidative motor units of the soleus, as seen by decreased pre- and post-synaptic membrane area, decreased pre- and post-synaptic membrane colocalization, increased acetylcholine receptor compactness, a decrease in endplate area and complexity, and deficits in neurofilament heavy chain. Our data also show evidence for metabolic dysregulation and myofiber atrophy that correlate with severity of NMJ pathology. We propose a model in which the dynamic communicative relationship between the motor neuron and muscle, along with the developmental subtype of the muscle, promotes motor unit subtype specific vulnerability, metabolic alterations, and NMJ pathology.

A Prediction Model for Peak Expiratory Flow Derived From Venous Blood Biomarkers and Clinical Factors in Amyotrophic Lateral Sclerosis

Although peripheral venous blood biomarkers are related to respiratory function in Amyotrophic lateral sclerosis (ALS) patients, there are still few prediction models that predict pulmonary function. This study aimed to investigate the venous blood biomarkers associated with respiratory function in patients with ALS from southwest China and to create prediction models based on those clinical biomarkers using logistic regression. A total of 319 patients with ALS from the retrospective cohort and 97 patients with ALS from the prospective cohort were enrolled in this study. A multivariable prediction model for the correlation between peak expiratory flow (PEF) and hematologic, biochemical laboratory parameters, and clinical factors in patients with ALS was created. Along with female patients, bulbar-onset, lower body mass index (BMI), later age of onset, lower level of creatinine, uric acid, triglyceride, and a higher level of high-density lipoprotein cholesterol (HDL_C) were related to reduced PEF. The area under the receiver operating characteristics (ROC) curve is.802 for the test set and.775 for the validation set. The study constructed a multivariable prediction model for PEF in patients with ALS. The results can be helpful for clinical practice to predict respiratory impairment.

Peak expiratory flow is a reliably household pulmonary function parameter correlates with disease severity and survival of patients with amyotrophic lateral sclerosis

Background

Amyotrophic lateral sclerosis (ALS) is an incurable and fatal neurodegenerative disease; most ALS patients die within 3 to 5 years after symptom onset, usually as a consequence of respiratory failure. In the present study, we aim to screen the survival-related pulmonary function parameters, and to explore the predictive value of peak expiratory flow (PEF) in disease severity and prognosis in patients with ALS.

Methods

The discovery cohort included 202 ALS patients, and the demographic and clinical characteristics of eligible patients were collected and pulmonary function tests were performed using MS-PFT spirometer. In the validation cohort, 62 newly diagnosed ALS patients performed the pulmonary function test by MS-PFT spirometer and household peak flow meter (KOKA) simultaneously.

Results

Among 12 pulmonary function parameters, FVC, FEV1, PEF, MEF75%, and MVV were identified to be independent predictive factors for survival. PEF was highly correlated with FVC (r = 0.797), MVV (r = 0.877), FEV1 (r = 0.847), and MEF75% (r = 0.963). Besides, the values of PEF were positively associated with disease severity (ALSFRS-R score, r_s = 0.539, P < 0.0001), and negatively associated with progression rate (ΔALSFRS-R, r_s = -0.316, P < 0.0001). Finally, we also confirmed that the values of KOKA-measured PEF were highly correlated with the ones measured using MS-PFT spirometer (r = 0.9644, p < 0.0001).

Conclusions

Our work emphasizes the critical role of PFTs in predicting prognosis of ALS patients. PEF is an easily available pulmonary function index, which is also a promising indicator in predicting disease severity and survival for ALS patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02635-z.

Ratio of urinary N-terminal titin fragment to urinary creatinine is a novel biomarker for amyotrophic lateral sclerosis

OBJECTIVE

We aimed to investigate the validity of urinary N-terminal titin fragment as a biomarker for amyotrophic lateral sclerosis (ALS).

METHODS

We consecutively enrolled patients with ALS (n=70) and healthy controls (HC) (n=43). We assessed the urinary titin N-terminal fragment, urinary neurotrophin receptor p75 extracellular domain, serum neurofilament light chain (NfL), motor functional measurements and prognosis. We used urinary creatinine (Cr) levels to normalise the urinary levels of titin fragment.

RESULTS

Compared with HC, patients with ALS had significantly increased urinary levels of titin N-terminal fragment normalised with Cr (titin/Cr) (ALS, 27.2 pmol/mg/dL; HC, 5.8 pmol/mg/dL; p<0.001), which were correlated with the scores of the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale (r=-0.422, p<0.001). A Cox proportional hazards model demonstrated that the high urinary level of titin/Cr was a survival predictor in patients with ALS. Multivariate analysis of prognostic factors showed that the urinary titin/Cr and serum NfL were independent factors for poor prognosis.

CONCLUSIONS

Our findings indicate that urinary N-terminal titin fragment is a non-invasive measure of muscle damage in ALS, which could be applied in disease monitoring and prediction of disease progression, in combination with serum NfL.

Effects of Physical Therapist Intervention on Pulmonary Function in Children With Cerebral Palsy: A Systematic Review and Meta-Analysis

OBJECTIVE

The purpose of this study was to evaluate the effects of physical therapy on pulmonary function and respiratory muscle strength in children with cerebral palsy (CP).

METHODS

A search of 10 databases was conducted for this systematic review. Initially, there were no language, study design, or time frame restrictions. All studies assessing the effect of physical therapy on the respiratory system in children with CP were included. Two reviewers independently extracted and documented data. The data extracted included description of the intervention (duration, therapeutic method) and study results (change of spirometric parameters, respiratory muscle strength). The effects of physical therapist treatment were calculated using software.

RESULTS

A total of 269 children aged 5 to 18 years from 10 studies were included. The included studies consisted of 5 different therapeutic methods (inspiratory muscle training [IMT], aerobic training, swimming, respiratory exercise, exercise with elastic bands). Physical therapist intervention led to a significant increase in the maximal expiratory pressure (MEP) (I2 = 0%), peak expiratory flow (I2 = 0%), and maximum oxygen consumption (I2 = 37%). A separate analysis of the most frequently used therapy (IMT) showed a positive effect on MEP (I2 = 0%) and maximal inspiratory pressure (I2 = 35%).

CONCLUSION

Various forms of physical therapy have potential to demonstrate a positive effect on maximal inspiratory pressure, MEP, and peak expiratory flow in children with CP. There is no possibility to recommend the best method and duration of the physical therapy; however, it can be suggested that physical therapy should be applied for at least 4 weeks and include IMT.

IMPACT

CP is one of the most common causes of physical disabilities in children, and pulmonary dysfunction is the leading cause of death in people with CP. Thus, it is warranted to seek different approaches that may improve pulmonary function in people with CP. This review has shown that various forms of physical therapy have potential to improve the pulmonary function of children with CP.

Disease mechanism, biomarker and therapeutics for spinal and bulbar muscular atrophy (SBMA)

Spinal and bulbar muscular atrophy (SBMA) is a hereditary neuromuscular disorder caused by CAG trinucleotide expansion in the gene encoding the androgen receptor (AR). In the central nervous system, lower motor neurons are selectively affected, whereas pathology of patients and animal models also indicates involvement of skeletal muscle including loss of fast-twitch type 2 fibres and increased slow-twitch type 1 fibres, together with a glycolytic-to-oxidative metabolic switch. Evaluation of muscle and fat using MRI, in addition to biochemical indices such as serum creatinine level, are promising biomarkers to track the disease progression. The serum level of creatinine starts to decrease before the onset of muscle weakness, followed by the emergence of hand tremor, a prodromal sign of the disease. Androgen-dependent nuclear accumulation of the polyglutamine-expanded AR is an essential step in the pathogenesis, providing therapeutic opportunities via hormonal manipulation and gene silencing with antisense oligonucleotides. Animal studies also suggest that hyperactivation of Src, alteration of autophagy and a mitochondrial deficit underlie the neuromuscular degeneration in SBMA and provide alternative therapeutic targets.

Muscle BDNF improves synaptic and contractile muscle strength in Kennedy's disease mice in a muscle-type specific manner

KEY POINTS

Muscle-derived neurotrophic factors may offer therapeutic promise for treating neuromuscular diseases. We report that a muscle-derived neurotrophic factor, BDNF, rescues synaptic and muscle function in a muscle-type specific manner in mice modelling Kennedy's disease (KD). We also find that BDNF rescues select molecular mechanisms in slow and fast muscle that may underlie the improved cellular function. We also report for the first time that expression of BDNF, but not other members of the neurotrophin family, is perturbed in muscle from patients with KD. Given that muscle BDNF had divergent therapeutic effects that depended on muscle type, a combination of neurotrophic factors may optimally rescue neuromuscular function via effects on both pre- and postsynaptic function, in the face of disease.

ABSTRACT

Deficits in muscle brain-derived neurotrophic factor (BDNF) correlate with neuromuscular deficits in mouse models of Kennedy's disease (KD), suggesting that restoring muscle BDNF might restore function. To test this possibility, transgenic mice expressing human BDNF in skeletal muscle were crossed with '97Q' KD mice. We found that muscle BDNF slowed disease, doubling the time between symptom onset and endstage. BDNF also improved expression of genes in muscle known to play key roles in neuromuscular function, including counteracting the expression of neonatal isoforms induced by disease. Intriguingly, BDNF's ameliorative effects differed between muscle types: synaptic strength was rescued only in slow-twitch muscle, while contractile strength was improved only in fast-twitch muscle. In sum, muscle BDNF slows disease progression, rescuing select cellular and molecular mechanisms that depend on fibre type. Muscle BDNF expression was also affected in KD patients, reinforcing its translational and therapeutic potential for treating this disorder.

Deterioration of muscle force and contractile characteristics are early pathological events in spinal and bulbar muscular atrophy mice

Spinal and bulbar muscular atrophy (SBMA), also known as Kennedy's Disease, is a late-onset X-linked progressive neuromuscular disease, which predominantly affects males. The pathological hallmarks of the disease are selective loss of spinal and bulbar motor neurons, accompanied by weakness, atrophy and fasciculations of bulbar and limb muscles. SBMA is caused by a CAG repeat expansion in the gene that encodes the androgen receptor (AR) protein. Disease manifestation is androgen dependent and results principally from a toxic gain of AR function. There are currently no effective treatments for this debilitating disease. It is important to understand the course of the disease in order to target therapeutics to key pathological stages. This is especially relevant in disorders such as SBMA, for which disease can be identified before symptom onset, through family history and genetic testing. To fully characterise the role of muscle in SBMA, we undertook a longitudinal physiological and histological characterisation of disease progression in the AR100 mouse model of SBMA. Our results show that the disease first manifests in skeletal muscle, before any motor neuron degeneration, which only occurs in late-stage disease. These findings reveal that alterations in muscle function, including reduced muscle force and changes in contractile characteristics, are early pathological events in SBMA mice and suggest that muscle-targeted therapeutics may be effective in SBMA.This article has an associated First Person interview with the first author of the paper.

Application of Automatic Kinematic Analysis Program for the Evaluation of Dysphagia in ALS patients

Dysphagia in amyotrophic lateral sclerosis (ALS) increases the risk of malnutrition, dehydration, and aspiration pneumonia. Kinematic analysis of videofluoroscopic swallowing study (VFSS) can provide detailed movement of the hyoid bone, revealing abnormalities of swallowing in ALS patients. We developed an automated kinematic analysis program (AKAP) that analyzes the trajectory of the hyoid bone via a visual tracking method. The aim of this study was to investigate the hyoid movement in ALS patients using AKAP and compare it with non-dysphagic subjects. Thirty ALS patients who underwent VFSS in Seoul National University Bundang Hospital between 2015 and 2017 were recruited. For comparison, 30 age-matched control subjects were also enrolled; the same swallowing study was conducted using thin fluid and yogurt. The hyoid bone movement was analyzed by evaluating the vertical and horizontal distances with four peak points (A, B, C, D), and the time of each point were also calculated. With respect to distance parameters, only vertical peak distance (distance between B, D points) during thin fluid swallowing was significantly decreased in ALS patients. (p = 0.038) With respect to temporal parameters, Time ABC, Time ABCD, and Duration C were significantly increased in ALS patients when swallowing both thin fluid and yogurt. (Time ABC p = 0.019, p = 0.002; Time ABCD p = 0.001, p = 0.004; Duration C p = 0.004, p = 0.025 respectively). This result revealed that dysphagia in ALS patient is caused by decreased velocity of hyoid bone movement due to the development of weakness in swallowing-related muscles. The parameters of kinematic analysis could be used to quantitatively evaluate dysphagia in motor neuron disease.

Molecular Mechanisms and Therapeutics for SBMA/Kennedy's Disease

Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular disease caused by a polyglutamine (polyQ) expansion in the androgen receptor (AR). Despite the fact that the monogenic cause of SBMA has been known for nearly 3 decades, there is no effective treatment for this disease, underscoring the complexity of the pathogenic mechanisms that lead to a loss of motor neurons and muscle in SBMA patients. In the current review, we provide an overview of the system-wide clinical features of SBMA, summarize the structure and function of the AR, discuss both gain-of-function and loss-of-function mechanisms of toxicity caused by polyQ-expanded AR, and describe the cell and animal models utilized in the study of SBMA. Additionally, we summarize previously conducted clinical trials which, despite being based on positive results from preclinical studies, proved to be largely ineffective in the treatment of SBMA; nonetheless, these studies provide important insights as researchers develop the next generation of therapies.

The prognostic value of spirometric tests in Amyotrophic Lateral Sclerosis patients

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) patients tend to develop progressive respiratory muscle weakness, leading to ventilatory failure and ineffective cough, principal causes of morbidity and mortality. Since patients are usually unaware of these symptoms, these are generally not noticed until the advanced stages and are associated with poor prognosis. The monitoring of respiratory function on a regular basis is therefore of great importance. Despite the availability of several pulmonary function tests, none of them was found to be the best indicator of the disease progression throughout the course of this condition. The main aim of our work was to evaluate the prognostic value of these respiratory measures evaluated in a brief period of observation and their correlation with motor functional impairments in an ALS cohort.

PATIENTS AND METHODS

Patients with ALS who had respiratory assessments performed and functional motor scales administered at baseline and six months later were included. All patients were assessed with forced vital capacity, both in seated and supine position (FVC; sFVC), peak expiratory flow (PEF), peak expiratory cough flow (PCEF), the revised ALS functional rating scale (ALSFRS-R), at baseline and after six months, and their disease progression rate (ΔFS) was obtained.

RESULTS

We included 73 patients with probable or definite ALS according to El-Escorial revised Criteria. At baseline, PCEF and PEF significantly correlated with ALSFRS-R total, bulbar and spinal subscores and ΔFS, while FVC% significantly correlated with ΔFS. After 6 months all the respiratory parameters significantly correlated with ALSFRS-R and all its subscores. Longitudinally, FVC%, sFVC% and PCEF significantly correlated with ΔFS and some of ALSFRS-R subscores. As concerns the survival analysis, monthly declines of FVC% and sFVC%, significantly correlated with the survival. The worse prognosis in terms of survival was finally found in those whose FVC% and sFVC% dropped below their respective cut-offs.

CONCLUSION

Throughout the course of ALS disease, the monitoring of several respiratory markers, namely FVC, sFVC, PEF and PCEF, plays a critical role in predicting the prognosis of these subjects, both in terms of survival and functional ability. The implementation of monthly cut-offs in the evaluation of FVC and sFVC may allow a faster recognition of those patients with worse prognosis and therefore an optimized tailored clinical care, as well as a better stratification in clinical trials.

Joint Indian Chest Society-National College of Chest Physicians (India) guidelines for spirometry

Although a simple and useful pulmonary function test, spirometry remains underutilized in India. The Indian Chest Society and National College of Chest Physicians (India) jointly supported an expert group to provide recommendations for spirometry in India. Based on a scientific grading of available published evidence, as well as other international recommendations, we propose a consensus statement for planning, performing and interpreting spirometry in a systematic manner across all levels of healthcare in India. We stress the use of standard equipment, and the need for quality control, to optimize testing. Important technical requirements for patient selection, and proper conduct of the vital capacity maneuver, are outlined. A brief algorithm to interpret and report spirometric data using minimal and most important variables is presented. The use of statistically valid lower limits of normality during interpretation is emphasized, and a listing of Indian reference equations is provided for this purpose. Other important issues such as peak expiratory flow, bronchodilator reversibility testing, and technician training are also discussed. We hope that this document will improve use of spirometry in a standardized fashion across diverse settings in India.

Study protocol for the MEXiletine hydrochloride administration trial: a placebo-controlled, randomised, double-blind, multicentre, crossover study of its efficacy and safety in spinal and bulbar muscular atrophy (MEXPRESS)

INTRODUCTION

Spinal and bulbar muscular atrophy (SBMA) is a slowly progressive neuromuscular disease. Cold exposure often leads to worsening of motor symptoms including paresis. Although mexiletine hydrochloride administration has been shown to be effective for the treatment of several muscular diseases, its effectiveness in SBMA has not been validated to date. The trial will test it as a symptomatic drug for cold paresis. This study is the first trial to evaluate the efficacy and safety of mexiletine hydrochloride administration in patients with SBMA.

METHODS AND ANALYSIS

A placebo-controlled, randomised, double-blind, multicentre, crossover clinical trial will be conducted to assess the safety and efficacy of mexiletine hydrochloride in patients with SBMA. The eligible patients will be assigned randomly in a 1:1 ratio to two groups in a double-blind manner. Participants will take mexiletine hydrochloride (300 mg/day) or a placebo orally three times a day for 4 weeks (period 1). After a 1-week washout period, participants will take the other drug for 4 weeks (period 2). The primary endpoint is the difference in distal latencies between room temperature and cold exposure conditions.

ETHICS AND DISSEMINATION

This study will be conducted in compliance with the Helsinki Declaration and the Ethical Guidelines for Medical and Health Research Involving Human Subjects by the Japanese government and has been approved by the ethics committee of Nagoya University Graduate School of Medicine, as a central institutional review board, and by each facility. The results will be disseminated in peer-reviewed journals and at scientific conferences.

TRIAL REGISTRATION NUMBER

UMIN000026150; Pre-results.

Beyond motor neurons: expanding the clinical spectrum in Kennedy's disease

Kennedy's disease, or spinal and bulbar muscular atrophy (SBMA), is an X-linked neuromuscular condition clinically characterised by weakness, atrophy and fasciculations of the limb and bulbar muscles, as a result of lower motor neuron degeneration. The disease is caused by an abnormally expanded triplet repeat expansions in the ubiquitously expressed androgen receptor gene, through mechanisms which are not entirely elucidated. Over the years studies from both humans and animal models have highlighted the involvement of cell populations other than motor neurons in SBMA, widening the disease phenotype. The most compelling aspect of these findings is their potential for therapeutic impact: muscle, for example, which is primarily affected in the disease, has been recently shown to represent a valid alternative target for therapy to motor neurons. In this review, we discuss the emerging study of the extra-motor neuron involvement in SBMA, which, besides increasingly pointing towards a multidisciplinary approach for affected patients, deepens our understanding of the pathogenic mechanisms and holds potential for providing new therapeutic targets for this disease.

Treatment with Creatine Monohydrate in Spinal and Bulbar Muscular Atrophy: Protocol for a Randomized, Double-Blind, Placebo-Controlled Trial

Background

Although spinal and bulbar muscular atrophy (SBMA) has been classified as a motor neuron disease, several reports have indicated the primary involvement of skeletal muscle in the pathogenesis of this devastating disease. Recent studies reported decreased intramuscular creatine levels in skeletal muscles in both patients with SBMA and transgenic mouse models of SBMA, which appears to contribute to muscle weakness.

Objective

The present study aimed to examine the efficacy and safety of oral creatine supplementation to improve motor function in patients with SBMA.

Methods

A randomized, double-blind, placebo-controlled, three-armed clinical trial was conducted to assess the safety and efficacy of creatine therapy in patients with SBMA. Patients with SBMA eligible for this study were assigned randomly in a 1:1:1 ratio to each group of placebo, 10 g, or 15 g daily dose of creatine monohydrate in a double-blind fashion. Participants took creatine or placebo orally 3 times a day for 8 weeks. Outcome measurements were results of neurological assessments, examinations, and questionnaires collected at baseline and at weeks 4, 8, and 16 after a washout period. The primary endpoint was the change in handgrip strength values from baseline to week 8. The secondary endpoints included the following: results of maximum voluntary isometric contraction tests of extremities; tongue pressure; results of the 15-foot timed walk test and the rise from bed test; modified quantitative myasthenia gravis score; respiratory function test results; activities of daily living assessed with the Revised Amyotrophic Lateral Sclerosis Functional Rating Scale and the Spinal and Bulbar Muscular Atrophy Functional Rating Scale; skeletal muscle mass measured with dual-energy X-ray absorptiometry; urinary 8-hydroxydeoxyguanosine levels; and questionnaires examining the quality of life, swallowing function, and fatigue.

Results

Participant enrollment in the trial started from June 2014 and follow-up was completed in July 2015. The study is currently being analyzed.

Conclusions

This is the first clinical trial evaluating creatine therapy in SBMA. Given that creatine serves as an energy source in skeletal muscles, recovery of intramuscular creatine concentration is expected to improve muscle strength.

Trial Registration

University Hospital Medical Information Network Clinical Trials Registry UMIN000012503; https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000014611 (Archived by WebCite at http://www.webcitation.org/6xOlbPkg3).