Intermittent theta burst stimulation (iTBS) versus 10 Hz high-frequency repetitive transcranial magnetic stimulation (rTMS) to alleviate treatment-resistant unipolar depression: A randomized controlled trial (THETA-DEP).

BACKGROUND: Recently intermittent theta burst stimulation (iTBS) proved to be non-inferior to conventional repetitive transcranial magnetic stimulation (10 Hz rTMS) in unipolar depression after failure of one antidepressant trial, but to date no randomized control trial assessed the ability of iTBS to improve depression level and quality of life in more resistant features of depression with a long-term (6 month) follow-up in comparison to 10 Hz rTMS. OBJECTIVES/HYPOTHESIS: The aim of our study was to compare the efficacy of 10 Hz rTMS and iTBS in treatment-resistant unipolar depression on response rates (50% decrease of MADRS scores at one month from baseline) and change in quality of life during a 6-month follow-up. In addition, we investigated whether some clinical features at baseline were associated with the response in the different groups. METHOD: Sixty patients were randomized in a double-blind, controlled study at the University Hospital Center of Nantes, and received 20 sessions of either rTMS or iTBS applied to the left dorsolateral prefrontal cortex targeted by neuronavigation. Statistical analysis used Fischer's exact test and Chi-square test as appropriate, linear mixed model, and logistic regression (occurrence of depressive relapse and factors associated with the therapeutic response). RESULTS: Included patients showed in mean more than 3 antidepressants trials. Response rates were 36.7% and 33.3%, and remission rates were 18.5% and 14.8%, in the iTBS and 10 Hz rTMS groups respectively. Both groups showed a similar significant reduction in depression scores and quality of life improvement at 6 months. We did not find any clinical predictive factor of therapeutic response in this sample. CONCLUSION: Our study suggests the clinical interest of iTBS stimulation (which is more time saving and cost-effective as conventional rTMS) to provide long-lasting improvement of depression and quality of life in highly resistant unipolar depression.

Homoplasmic mitochondrial tRNAPro mutation causing exercise-induced muscle swelling and fatigue.

OBJECTIVE: To demonstrate the causal role in disease of the MT-TP m.15992A>T mutation observed in patients from 5 independent families. METHODS: Lactate measurement, muscle histology, and mitochondrial activities in patients; PCR-based analyses of the size, amount, and sequence of muscle mitochondrial DNA (mtDNA) and proportion of the mutation; respiration, mitochondrial activities, proteins, translation, transfer RNA (tRNA) levels, and base modification state in skin fibroblasts and cybrids; and reactive oxygen species production, proliferation in the absence of glucose, and plasma membrane potential in cybrids. RESULTS: All patients presented with severe exercise intolerance and hyperlactatemia. They were associated with prominent exercise-induced muscle swelling, conspicuous in masseter muscles (2 families), and/or with congenital cataract (2 families). MRI confirmed exercise-induced muscle edema. Muscle disclosed severe combined respiratory defect. Muscle mtDNA had normal size and amount. Its sequence was almost identical in all patients, defining the haplotype as J1c10, and sharing 31 variants, only 1 of which, MT-TP m.15992A>T, was likely pathogenic. The mutation was homoplasmic in all tissues and family members. Fibroblasts and cybrids with homoplasmic mutation had defective respiration, low complex III activity, and decreased tRNAPro amount. Their respiratory complexes amount and tRNAPro aminoacylation appeared normal. Low proliferation in the absence of glucose demonstrated the relevance of the defects on cybrid biology while abnormal loss of cell volume when faced to plasma membrane depolarization provided a link to the muscle edema observed in patients. CONCLUSIONS: The homoplasmic MT-TP m.15992A>T mutation in the J1c10 haplotype causes exercise-induced muscle swelling and fatigue.

Force-sharing within the Triceps Surae: An Achilles Heel in Achilles Tendinopathy.

PURPOSE: The primary aim of this study was to determine whether the distribution of force between the three heads of the triceps surae differs between people with Achilles tendinopathy and controls. We also aimed to determine the effect of this force distribution on subtendon strain. METHODS: Data were collected for 21 participants with Achilles tendinopathy and 21, case-wise paired, asymptomatic controls. Ultrasonography was used to measure muscle volume, fascicle length, pennation angle and subtendon length at rest. Muscle activation was estimated using surface electromyography during maximal and submaximal isometric plantarflexion tasks. The product of normalized activation, physiological cross-sectional area, and the cosine of the pennation angle was considered as an index of individual muscle force. Displacement of the distal myotendinous junction of each muscle was measured during the submaximal contractions. RESULTS: The contribution of the gastrocnemius lateralis to the overall triceps surae physiological cross-sectional area and activation was 8.5% (P = 0.047, d = 0.75) and 24.7% lower (main effect group P = 0.009, d = 0.67) in people with Achilles tendinopathy than in the controls, respectively. Consequently, gastrocnemius lateralis contributed approximately 28% less (main effect group P = 0.025, d = 0.62) of the triceps surae force in people with Achilles tendinopathy. The contribution of gastrocnemius medialis and soleus was not different between groups. Subtendon strain was not different between groups (P = 0.835). CONCLUSIONS: These results provide evidence for a difference in force-sharing strategy within the triceps surae in people with Achilles tendinopathy compared with the controls. Whether this altered strategy is a cause or a consequence of Achilles tendinopathy should be explored further.

Efficacy of intermittent Theta Burst Stimulation (iTBS) and 10-Hz high-frequency repetitive transcranial magnetic stimulation (rTMS) in treatment-resistant unipolar depression: study protocol for a randomised controlled trial.

BACKGROUND: The treatment of depression remains a challenge since at least 40% of patients do not respond to initial antidepressant therapy and 20% present chronic symptoms (more than 2 years despite standard treatment administered correctly). Repetitive transcranial magnetic stimulation (rTMS) is an effective adjuvant therapy but still not ideal. Intermittent Theta Burst Stimulation (iTBS), which has only been used recently in clinical practice, could have a faster and more intense effect compared to conventional protocols, including 10-Hz high-frequency rTMS (HF-rTMS). However, no controlled study has so far highlighted the superiority of iTBS in resistant unipolar depression. METHODS/DESIGN: This paper focuses on the design of a randomised, controlled, double-blind, single-centre study with two parallel arms, carried out in France, in an attempt to assess the efficacy of an iTBS protocol versus a standard HF- rTMS protocol. Sixty patients aged between 18 and 75 years of age will be enrolled. They must be diagnosed with major depressive disorder persisting despite treatment with two antidepressants at an effective dose over a period of 6 weeks during the current episode. The study will consist of two phases: a treatment phase comprising 20 sessions of rTMS to the left dorsolateral prefrontal cortex, localised via a neuronavigation system and a 6-month longitudinal follow-up. The primary endpoint will be the number of responders per group, defined by a decrease of at least 50% in the initial score on the Montgomery and Asberg Rating Scale (MADRS) at the end of rTMS sessions. The secondary endpoints will be: response rate 1 month after rTMS sessions; number of remissions defined by a MADRS score of <8 at the endpoint and 1 month after; the number of responses and remissions maintained over the next 6 months; quality of life; and the presence of predictive markers of the therapeutic response: clinical (dimensional scales), neuropsychological (evaluation of cognitive functions), motor (objective motor testing) and neurophysiological (cortical excitability measurements). DISCUSSION: The purpose of our study is to check the assumption of iTBS superiority in the management of unipolar depression and we will discuss its effect over time. In case of a significant increase in the number of therapeutic responses with a prolonged effect, the iTBS protocol could be considered a first-line protocol in resistant unipolar depression. TRIAL REGISTRATION: ClinicalTrials.gov, Identifier NCT02376491 . Registered on 17 February 2015 at http://clinicaltrials.gov .

Electrochemical skin conductance for quantitative assessment of sweat function: Normative values in children.

OBJECTIVES: The Sudoscan™ system (Impeto Medical, Paris, France) has been recently proposed as a standardized, easy, painless tool for sudomotor function assessment. It is now used as an additional diagnostic tool in small fibre neuropathy. So far, no work has been published in children. The aim of this study was to measure electrochemical skin conductance (ESC) using the Sudoscan™ system in children in order to assess its feasibility and to provide normative values. METHODS: 100 children were included in the study: 55 girls and 45 boys, age rank 2-17, mean 10.5 y. They were accompanying their brother or sister who came as outclinic patients in the Department of Paediatrics or the Department of Paediatric surgery of the University Hospital. RESULTS: All subjects underwent the test. It was performed without any difficulty, except for some of the youngest who sometimes had some trouble in keeping calm for 3 min over the plates. 4 subjects who took the test were excluded from the analysis (2 diabetic patients and 2 having had previous chemotherapy). ESC was quite stable along childhood with an overall 80.1 µS value for hands and 81.9 µS for feet, very similar to what is observed in adults. CONCLUSION: Maturation process seems to occur early in life, in accordance to sudomotor control when assessed by sympathetic skin response, which is also recorded early in infancy. SIGNIFICANCE: ESC measurement is a simple and easy-to-perform test that can be performed in the clinical setting in children in 5 min.

Vincristine-induced neuropathy: Atypical electrophysiological patterns in children.

INTRODUCTION: Vincristine is an antimitotic agent used for treatment of leukemia, lymphomas, and cancers. Its main side effect is a dose-related, length-dependent (LD) axonal neuropathy. METHODS: We performed electrodiagnostic (EDx) examinations in 17 children who had been treated with vincristine and who presented with the clinical picture of a peripheral neuropathy. RESULTS: The mean dose of vincristine was 8.5 ± 4.0 mg/m(2) . Clinical motor symptoms were more frequent and more severe than sensory ones. Thirteen children presented with a motor deficit, 4 of whom could no longer walk. EDx examination showed an axonal neuropathy with a non-length-dependent (NLD) pattern in 9 children and an LD pattern in 8. A major motor predominance was encountered in 12 patients. CONCLUSIONS: The electrophysiological and clinical motor predominance described differs from the mainly sensory neuropathy reported in adults. Incomplete myelination due to young age may have resulted in greater sensitivity of some nerves to neurotoxic agents.

Guillain-Barré syndrome during childhood: particular clinical and electrophysiological features.

INTRODUCTION: Guillain-Barré syndrome (GBS) has some specific characteristics in children. METHODS: In this study we reviewed the clinical, laboratory, electrophysiological, and prognosis features of the 19 children diagnosed with GBS at Nantes University Hospital from 2000 to 2011. RESULTS: Gait disturbance and leg pain were the most frequent presenting symptoms. Electrophysiological examinations revealed significant abnormalities even when performed within the first week after onset. Decreased distal CMAP amplitude was noted in 89% of cases. The pattern indicated an acute inflammatory demyelinating polyneuropathy in 95% of cases and acute motor axonal neuropathy in the remaining 5%. About two-thirds of the children were treated with intravenous immunoglobulin. After >1 year of follow-up, 17 patients had complete recovery. CONCLUSION: Gait disorder, leg pain, a high rate of distal conduction block, and a good prognosis are among the main specific features of GBS in childhood.

Immune response and mitochondrial metabolism are commonly deregulated in DMD and aging skeletal muscle.

Duchenne Muscular Dystrophy (DMD) is a complex process involving multiple pathways downstream of the primary genetic insult leading to fatal muscle degeneration. Aging muscle is a multifactorial neuromuscular process characterized by impaired muscle regeneration leading to progressive atrophy. We hypothesized that these chronic atrophying situations may share specific myogenic adaptative responses at transcriptional level according to tissue remodeling. Muscle biopsies from four young DMD and four AGED subjects were referred to a group of seven muscle biopsies from young subjects without any neuromuscular disorder and explored through a dedicated expression microarray. We identified 528 differentially expressed genes (out of 2,745 analyzed), of which 328 could be validated by an exhaustive meta-analysis of public microarray datasets referring to DMD and Aging in skeletal muscle. Among the 328 validated co-expressed genes, 50% had the same expression profile in both groups and corresponded to immune/fibrosis responses and mitochondrial metabolism. Generalizing these observed meta-signatures with large compendia of public datasets reinforced our results as they could be also identified in other pathological processes and in diverse physiological conditions. Focusing on the common gene signatures in these two atrophying conditions, we observed enrichment in motifs for candidate transcription factors that may coordinate either the immune/fibrosis responses (ETS1, IRF1, NF1) or the mitochondrial metabolism (ESRRA). Deregulation in their expression could be responsible, at least in part, for the same transcriptome changes initiating the chronic muscle atrophy. This study suggests that distinct pathophysiological processes may share common gene responses and pathways related to specific transcription factors.

Apoptosis in mitochondrial myopathies is linked to mitochondrial proliferation.

Increased susceptibility to apoptosis has been shown in many models of mitochondrial defects but its relevance to human diseases is still discussed. We addressed the presence of apoptosis in muscle from patients with mitochondrial DNA (mtDNA) disorders. Taking advantage of the mosaic pattern of muscle morphological anomalies associated with heteroplasmic mtDNA alterations, we have used an in situ approach to address the relationship between apoptosis and respiratory defect, mitochondrial proliferation and mutation load. Different patterns of mitochondrial morphological alterations were provided by the analysis of muscles with large mtDNA deletion (16 cases) or with the MELAS mutation (4 cases). The patient's age at biopsy ranged from 0.4 to 66 years and the muscle mutant mtDNA proportion from 32 to 82%. Apoptotic muscle fibres were observed in a small proportion of muscle fibres of 16 out of the 20 biopsies by three different detection methods for different steps of apoptosis: caspase 3 activation, fragmentation of nuclear DNA [terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay] or overexpression of the pro-apoptotic factor Bax. Analysis of apoptotic features in parallel to cytochrome c oxidase (COX) and succinate dehydrogenase activity of more than 34,000 individual muscle fibres showed that apoptosis occurred only in muscle fibres with mitochondrial proliferation (ragged red fibres, RRF) irrespective of their COX activity. Molecular analyses of single muscle fibres evidenced that, as expected, the presence of COX defect was associated with higher proportion of mutant mtDNA and lower amount of normal mtDNA. Within COX-defective fibres, the presence of mitochondrial proliferation was associated with increase of the mtDNA content but without change in the ratio between normal and mutant mtDNA molecules, thus showing that mitochondrial proliferation was accompanied by similar amplification of normal and mutant mtDNA molecules. Within RRF, apoptosis was associated with higher mutation proportion, suggesting that it was provoked by severe respiratory defect in the same time as increased mitochondrial mass. In conclusion, apoptosis most probably contributes to mitochondrial pathology. It is tightly linked to mitochondrial proliferation and high mutation load. When considering training therapeutics, one will have to take into account the possibility to induce apoptosis in parallel to mitochondrial proliferation.

A novel mutation in the mitochondrial tRNA Asn gene associated with a lethal disease.

We describe a lethal mitochondrial disease in a 10-month-old child who presented with encephalomyopathy. Histochemical and electron microscopy examinations of skeletal muscle biopsy revealed abnormal mitochondria associated with a combined deficiency of complexes I and IV. After excluding mitochondrial DNA deletions and depletion, direct sequencing was used to screen for mutation in all transfer RNA (tRNA) genes. A T-to-C substitution at position 5693 in the tRNA(Asn) gene was found in blood and muscle. Microdissection of muscle biopsy and its analysis revealed the highest level of this mutation in cytochrome c oxidase (COX)-negative fibres. We suggest that this novel mutation would affect the anticodon loop structure of the tRNA(Asn) and cause a fatal mitochondrial disease.

Effect of 1-year oral administration of dehydroepiandrosterone to 60- to 80-year-old individuals on muscle function and cross-sectional area: a double-blind placebo-controlled trial.

BACKGROUND: The age-related decline of dehydroepiandrosterone and its sulfate ester levels is thought to be related to the development of age-associated usual modifications, such as neuromuscular function impairments. It is often claimed that individuals can enhance their muscular capacity by boosting dehydroepiandrosterone levels through oral supplementation. However, to our knowledge, there have been no controlled studies on a significant number of individuals demonstrating positive effects on the neuromuscular system. This study determines if 1-year administration of a replacement dose of dehydroepiandrosterone, 50 mg/d, orally administered, could have a beneficial influence on several determinants of the muscular function altered during aging. METHODS: This work was completed within the frame of the DHEAge Study, which was conducted in France from March 1, 1998, to October 31, 1999. It was performed on 280 healthy ambulatory and independent men and women aged 60 to 80 years. The study design was a double-blind placebo-controlled trial. Dehydroepiandrosterone sulfate serum concentration, handgrip strength, isometric and isokinetic knee muscle strength, and thigh (fat and muscle) cross-sectional area were analyzed before and just after 12 months of placebo or dehydroepiandrosterone treatment. RESULTS: The results give evidence that dehydroepiandrosterone administration restores dehydroepiandrosterone sulfate serum concentrations to the normal range for young adults (aged 20-50 years). However, no positive effect inherent to dehydroepiandrosterone treatment was observed either on muscle strength or in muscle and fat cross-sectional areas. CONCLUSIONS: The compensation of the deficit of dehydroepiandrosterone during aging using a 50-mg/d dose does not induce beneficial effects on muscle state in healthy subjects. The conditions in which dehydroepiandrosterone could contribute to preserve or improve muscle strength and morphological features still need to be determined.

Ageing muscle: clonal expansions of mitochondrial DNA point mutations and deletions cause focal impairment of mitochondrial function.

Although mitochondrial DNA deletions have been shown to accumulate in cytochrome c oxidase deficient muscle fibres of ageing muscle, this has not been demonstrated for point mutations. In this study, we investigated the occurrence of mitochondrial DNA alterations (point mutations and deletions) in cytochrome c oxidase deficient muscle fibres from 14 individuals, without muscle disease, aged 69-82 years. Immunohistochemical investigation showed that the majority of the cytochrome c oxidase deficient muscle fibres expressed reduced levels of subunit II of cytochrome c oxidase, which is encoded by mitochondrial DNA, whereas there was normal or increased expression of subunit IV of cytochrome c oxidase, which is encoded by nuclear DNA. This pattern is typical for mitochondrial DNA mutations causing impaired mitochondrial translation. Single muscle fibres (109 cytochrome c oxidase deficient and 109 normal fibres) were dissected and their DNA extracted. Mitochondrial DNA point mutations were searched for in five tRNA genes by denaturing gradient gel electrophoresis while deletions were looked for by polymerase chain reaction amplification. High levels of clonally expanded point mutations were identified in eight cytochrome c oxidase deficient fibres but in none of the normal ones. They included the previously described pathogenic tRNALeu(UUR)A3243G and tRNALysA8344G mutations and three original mutations: tRNAMetT4460C, tRNAMetG4421A, and a 3-bp deletion in the tRNALeu(UUR) gene. Four different large-scale mitochondrial DNA deletions were identified in seven cytochrome c oxidase deficient fibres and in one of the normal ones. There was no evidence of depletion of mitochondrial DNA by in situ hybridisation experiments. Our data show that mitochondrial DNA point mutations, as well as large-scale deletions, are associated with cytochrome c oxidase deficient muscle fibre segments in ageing. Their focal accumulation causes significant impairment of mitochondrial function in individual cells in spite of low overall levels of mitochondrial DNA mutations in muscle.