Mutations in DNMT3B Modify Epigenetic Repression of the D4Z4 Repeat and the Penetrance of Facioscapulohumeral Dystrophy.

Facioscapulohumeral dystrophy (FSHD) is associated with somatic chromatin relaxation of the D4Z4 repeat array and derepression of the D4Z4-encoded DUX4 retrogene coding for a germline transcription factor. Somatic DUX4 derepression is caused either by a 1-10 unit repeat-array contraction (FSHD1) or by mutations in SMCHD1, which encodes a chromatin repressor that binds to D4Z4 (FSHD2). Here, we show that heterozygous mutations in DNA methyltransferase 3B (DNMT3B) are a likely cause of D4Z4 derepression associated with low levels of DUX4 expression from the D4Z4 repeat and increased penetrance of FSHD. Recessive mutations in DNMT3B were previously shown to cause immunodeficiency, centromeric instability, and facial anomalies (ICF) syndrome. This study suggests that transcription of DUX4 in somatic cells is modified by variations in its epigenetic state and provides a basis for understanding the reduced penetrance of FSHD within families.

Strength training and aerobic exercise training for muscle disease.

BACKGROUND: Strength training or aerobic exercise programmes, or both, might optimise muscle and cardiorespiratory function and prevent additional disuse atrophy and deconditioning in people with a muscle disease. This is an update of a review first published in 2004 and last updated in 2013. We undertook an update to incorporate new evidence in this active area of research. OBJECTIVES: To assess the effects (benefits and harms) of strength training and aerobic exercise training in people with a muscle disease. SEARCH METHODS: We searched Cochrane Neuromuscular's Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL in November 2018 and clinical trials registries in December 2018. SELECTION CRITERIA: Randomised controlled trials (RCTs), quasi-RCTs or cross-over RCTs comparing strength or aerobic exercise training, or both lasting at least six weeks, to no training in people with a well-described muscle disease diagnosis. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included 14 trials of aerobic exercise, strength training, or both, with an exercise duration of eight to 52 weeks, which included 428 participants with facioscapulohumeral muscular dystrophy (FSHD), dermatomyositis, polymyositis, mitochondrial myopathy, Duchenne muscular dystrophy (DMD), or myotonic dystrophy. Risk of bias was variable, as blinding of participants was not possible, some trials did not blind outcome assessors, and some did not use an intention-to-treat analysis. Strength training compared to no training (3 trials) For participants with FSHD (35 participants), there was low-certainty evidence of little or no effect on dynamic strength of elbow flexors (MD 1.2 kgF, 95% CI -0.2 to 2.6), on isometric strength of elbow flexors (MD 0.5 kgF, 95% CI -0.7 to 1.8), and ankle dorsiflexors (MD 0.4 kgF, 95% CI -2.4 to 3.2), and on dynamic strength of ankle dorsiflexors (MD -0.4 kgF, 95% CI -2.3 to 1.4). For participants with myotonic dystrophy type 1 (35 participants), there was very low-certainty evidence of a slight improvement in isometric wrist extensor strength (MD 8.0 N, 95% CI 0.7 to 15.3) and of little or no effect on hand grip force (MD 6.0 N, 95% CI -6.7 to 18.7), pinch grip force (MD 1.0 N, 95% CI -3.3 to 5.3) and isometric wrist flexor force (MD 7.0 N, 95% CI -3.4 to 17.4). Aerobic exercise training compared to no training (5 trials) For participants with DMD there was very low-certainty evidence regarding the number of leg revolutions (MD 14.0, 95% CI -89.0 to 117.0; 23 participants) or arm revolutions (MD 34.8, 95% CI -68.2 to 137.8; 23 participants), during an assisted six-minute cycle test, and very low-certainty evidence regarding muscle strength (MD 1.7, 95% CI -1.9 to 5.3; 15 participants). For participants with FSHD, there was low-certainty evidence of improvement in aerobic capacity (MD 1.1 L/min, 95% CI 0.4 to 1.8, 38 participants) and of little or no effect on knee extension strength (MD 0.1 kg, 95% CI -0.7 to 0.9, 52 participants). For participants with dermatomyositis and polymyositis (14 participants), there was very low-certainty evidence regarding aerobic capacity (MD 14.6, 95% CI -1.0 to 30.2). Combined aerobic exercise and strength training compared to no training (6 trials) For participants with juvenile dermatomyositis (26 participants) there was low-certainty evidence of an improvement in knee extensor strength on the right (MD 36.0 N, 95% CI 25.0 to 47.1) and left (MD 17 N 95% CI 0.5 to 33.5), but low-certainty evidence of little or no effect on maximum force of hip flexors on the right (MD -9.0 N, 95% CI -22.4 to 4.4) or left (MD 6.0 N, 95% CI -6.6 to 18.6). This trial also provided low-certainty evidence of a slight decrease of aerobic capacity (MD -1.2 min, 95% CI -1.6 to 0.9). For participants with dermatomyositis and polymyositis (21 participants), we found very low-certainty evidence for slight increases in muscle strength as measured by dynamic strength of knee extensors on the right (MD 2.5 kg, 95% CI 1.8 to 3.3) and on the left (MD 2.7 kg, 95% CI 2.0 to 3.4) and no clear effect in isometric muscle strength of eight different muscles (MD 1.0, 95% CI -1.1 to 3.1). There was very low-certainty evidence that there may be an increase in aerobic capacity, as measured with time to exhaustion in an incremental cycle test (17.5 min, 95% CI 8.0 to 27.0) and power performed at VO2 max (maximal oxygen uptake) (18 W, 95% CI 15.0 to 21.0). For participants with mitochondrial myopathy (18 participants), we found very low-certainty evidence regarding shoulder muscle (MD -5.0 kg, 95% CI -14.7 to 4.7), pectoralis major muscle (MD 6.4 kg, 95% CI -2.9 to 15.7), and anterior arm muscle strength (MD 7.3 kg, 95% CI -2.9 to 17.5). We found very low-certainty evidence regarding aerobic capacity, as measured with mean time cycled (MD 23.7 min, 95% CI 2.6 to 44.8) and mean distance cycled until exhaustion (MD 9.7 km, 95% CI 1.5 to 17.9). One trial in myotonic dystrophy type 1 (35 participants) did not provide data on muscle strength or aerobic capacity following combined training. In this trial, muscle strength deteriorated in one person and one person had worse daytime sleepiness (very low-certainty evidence). For participants with FSHD (16 participants), we found very low-certainty evidence regarding muscle strength, aerobic capacity and VO2 peak; the results were very imprecise. Most trials reported no adverse events other than muscle soreness or joint complaints (low- to very low-certainty evidence). AUTHORS' CONCLUSIONS: The evidence regarding strength training and aerobic exercise interventions remains uncertain. Evidence suggests that strength training alone may have little or no effect, and that aerobic exercise training alone may lead to a possible improvement in aerobic capacity, but only for participants with FSHD. For combined aerobic exercise and strength training, there may be slight increases in muscle strength and aerobic capacity for people with dermatomyositis and polymyositis, and a slight decrease in aerobic capacity and increase in muscle strength for people with juvenile dermatomyositis. More research with robust methodology and greater numbers of participants is still required.

Strength training and aerobic exercise training for muscle disease.

BACKGROUND: Strength training or aerobic exercise programmes might optimise muscle and cardiorespiratory function and prevent additional disuse atrophy and deconditioning in people with a muscle disease. This is an update of a review first published in 2004. OBJECTIVES: To examine the safety and efficacy of strength training and aerobic exercise training in people with a muscle disease. SEARCH METHODS: We searched the Cochrane Neuromuscular Disease Group Specialized Register (July 2012), CENTRAL (2012 Issue 3 of 4), MEDLINE (January 1946 to July 2012), EMBASE (January 1974 to July 2012), EMBASE Classic (1947 to 1973) and CINAHL (January 1982 to July 2012). SELECTION CRITERIA: Randomised or quasi-randomised controlled trials comparing strength training or aerobic exercise programmes, or both, to no training, and lasting at least six weeks, in people with a well-described diagnosis of a muscle disease.We did not use the reporting of specific outcomes as a study selection criterion. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted the data obtained from the full text-articles and from the original investigators. We collected adverse event data from included studies. MAIN RESULTS: We included five trials (170 participants). The first trial compared the effect of strength training versus no training in 36 people with myotonic dystrophy. The second trial compared aerobic exercise training versus no training in 14 people with polymyositis and dermatomyositis. The third trial compared strength training versus no training in a factorial trial that also compared albuterol with placebo, in 65 people with facioscapulohumeral muscular dystrophy (FSHD). The fourth trial compared combined strength training and aerobic exercise versus no training in 18 people with mitochondrial myopathy. The fifth trial compared combined strength training and aerobic exercise versus no training in 35 people with myotonic dystrophy type 1.In both myotonic dystrophy trials and the dermatomyositis and polymyositis trial there were no significant differences between training and non-training groups for primary and secondary outcome measures. The risk of bias of the strength training trial in myotonic dystrophy and the aerobic exercise trial in polymyositis and dermatomyositis was judged as uncertain, and for the combined strength training and aerobic exercise trial, the risk of bias was judged as adequate. In the FSHD trial, for which the risk of bias was judged as adequate, a +1.17 kg difference (95% confidence interval (CI) 0.18 to 2.16) in dynamic strength of elbow flexors in favour of the training group reached statistical significance. In the mitochondrial myopathy trial, there were no significant differences in dynamic strength measures between training and non-training groups. Exercise duration and distance cycled in a submaximal endurance test increased significantly in the training group compared to the control group. The differences in mean time and mean distance cycled till exhaustion between groups were 23.70 min (95% CI 2.63 to 44.77) and 9.70 km (95% CI 1.51 to 17.89), respectively. The risk of bias was judged as uncertain. In all trials, no adverse events were reported. AUTHORS' CONCLUSIONS: Moderate-intensity strength training in myotonic dystrophy and FSHD and aerobic exercise training in dermatomyositis and polymyositis and myotonic dystrophy type I appear to do no harm, but there is insufficient evidence to conclude that they offer benefit. In mitochondrial myopathy, aerobic exercise combined with strength training appears to be safe and may be effective in increasing submaximal endurance capacity. Limitations in the design of studies in other muscle diseases prevent more general conclusions in these disorders.

Hypothermia after CPR prolongs conduction times of somatosensory evoked potentials.

BACKGROUND: To investigate the effect of mild hypothermia on conduction times and amplitudes of median nerve somatosensory evoked potentials (SEP) in patients after cardiopulmonary resuscitation (CPR). METHODS: Patients treated with hypothermia after CPR who underwent SEP recording during hypothermia and after rewarming were selected from a prospectively collected database. Latencies and amplitudes of N9 (peripheral conduction time, PCT), N13, and N20 were measured. The central conduction time (CCT) was defined as peak-peak latency N13-N20. Recordings of 25 patients were assessed by a second observer to determine the intraclass correlation coefficient (ICC). RESULTS: A total of 115 patients were included. The mean body temperature at SEP during hypothermia was 33.1 °C (SD 0.8) and after rewarming 37.1 °C (SD 0.8). Mean latencies of N9, N13, and N20 and mean CCT were longer during hypothermia. There were no consistent differences in amplitudes. There was an almost perfect ICC for assessment of latencies and amplitudes. CONCLUSIONS: This study showed that PCT and CCT of median nerve SEP were prolonged during treatment with hypothermia after CPR compared with after rewarming. Amplitudes did not differ consistently.

Second intravenous immunoglobulin dose in patients with Guillain-Barré syndrome with poor prognosis (SID-GBS): a double-blind, randomised, placebo-controlled trial.

BACKGROUND: Treatment with one standard dose (2 g/kg) of intravenous immunoglobulin is insufficient in a proportion of patients with severe Guillain-Barré syndrome. Worldwide, around 25% of patients severely affected with the syndrome are given a second intravenous immunoglobulin dose (SID), although it has not been proven effective. We aimed to investigate whether a SID is effective in patients with Guillain-Barré syndrome with a predicted poor outcome. METHODS: In this randomised, double-blind, placebo-controlled trial (SID-GBS), we included patients (≥12 years) with Guillain-Barré syndrome admitted to one of 59 participating hospitals in the Netherlands. Patients were included on the first day of standard intravenous immunoglobulin treatment (2 g/kg over 5 days). Only patients with a poor prognosis (score of ≥6) according to the modified Erasmus Guillain-Barré syndrome Outcome Score were randomly assigned, via block randomisation stratified by centre, to SID (2 g/kg over 5 days) or to placebo, 7-9 days after inclusion. Patients, outcome adjudicators, monitors, and the steering committee were masked to treatment allocation. The primary outcome measure was the Guillain-Barré syndrome disability score 4 weeks after inclusion. All patients in whom allocated trial medication was started were included in the modified intention-to-treat analysis. This study is registered with the Netherlands Trial Register, NTR 2224/NL2107. FINDINGS: Between Feb 16, 2010, and June 5, 2018, 327 of 339 patients assessed for eligibility were included. 112 had a poor prognosis. Of those, 93 patients with a poor prognosis were included in the modified intention-to-treat analysis: 49 (53%) received SID and 44 (47%) received placebo. The adjusted common odds ratio for improvement on the Guillain-Barré syndrome disability score at 4 weeks was 1·4 (95% CI 0·6-3·3; p=0·45). Patients given SID had more serious adverse events (35% vs 16% in the first 30 days), including thromboembolic events, than those in the placebo group. Four patients died in the intervention group (13-24 weeks after randomisation). INTERPRETATION: Our study does not provide evidence that patients with Guillain-Barré syndrome with a poor prognosis benefit from a second intravenous immunoglobulin course; moreover, it entails a risk of serious adverse events. Therefore, a second intravenous immunoglobulin course should not be considered for treatment of Guillain-Barre syndrome because of a poor prognosis. The results indicate the need for treatment trials with other immune modulators in patients severely affected by Guillain-Barré syndrome. FUNDING: Prinses Beatrix Spierfonds and Sanquin Plasma Products.

Strength training and aerobic exercise training for muscle disease.

BACKGROUND: Strength training or aerobic exercise programmes might optimise muscle and cardiorespiratory function and prevent additional disuse atrophy and deconditioning in people with a muscle disease. OBJECTIVES: To examine the safety and efficacy of strength training and aerobic exercise training in people with a muscle disease. SEARCH STRATEGY: We searched the Cochrane Neuromuscular Disease Group Trials Specialized Register (July 2009), the Cochrane Rehabilitation and Related Therapies Field Register (October 2002, August 2008 and July 2009), The Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2009) MEDLINE (January 1966 to July 2009), EMBASE (January 1974 to July 2009), EMBASE Classic (1947 to 1973) and CINAHL (January 1982 to July 2009). SELECTION CRITERIA: Randomised or quasi-randomised controlled trials comparing strength training or aerobic exercise programmes, or both, to no training, and lasting at least 10 weeks.For strength training Primary outcome: static or dynamic muscle strength. Secondary: muscle endurance or muscle fatigue, functional assessments, quality of life, muscle membrane permeability, pain and experienced fatigue.For aerobic exercise training Primary outcome: aerobic capacity expressed as work capacity. Secondary: aerobic capacity (oxygen consumption, parameters of cardiac or respiratory function), functional assessments, quality of life, muscle membrane permeability, pain and experienced fatigue. DATA COLLECTION AND ANALYSIS: Two authors independently assessed trial quality and extracted the data. MAIN RESULTS: We included three trials (121 participants). The first compared the effect of strength training versus no training in 36 people with myotonic dystrophy. The second trial compared strength training versus no training, both combined with albuterol or placebo, in 65 people with facioscapulohumeral muscular dystrophy. The third trial compared combined strength training and aerobic exercise versus no training in 18 people with mitochondrial myopathy. In the myotonic dystrophy trial there were no significant differences between training and non-training groups for primary and secondary outcome measures. In the facioscapulohumeral muscular dystrophy trial only a +1.17 kg difference (95% confidence interval 0.18 to 2.16) in dynamic strength of elbow flexors in favour of the training group reached statistical significance. In the mitochondrial myopathy trial there were no significant differences in dynamic strength measures between training and non-training groups. Exercise duration and distance cycled in a submaximal endurance test increased significantly in the training group compared to the control group. AUTHORS' CONCLUSIONS: In myotonic dystrophy and facioscapulohumeral muscular dystrophy, moderate-intensity strength training appears not to do harm but there is insufficient evidence to conclude that it offers benefit. In mitochondrial myopathy, aerobic exercise combined with strength training appears to be safe and may be effective in increasing submaximal endurance capacity. Limitations in the design of studies in other muscle diseases prevent more general conclusions in these disorders.