Angela Genge

Recovery of N-acetylaspartate in corticomotor neurons of patients with ALS after riluzole therapy

RILUZOLE, a glutamate antagonist, has been shown to be efficacious in the treatment of patients with amyotrophic lateral sclerosis (ALS), allowing prolonged survival and time to tracheostomy. The efficacy of riluzole in thought to result from reduced glutamate excitotoxicity on motor neurons of patients with ALS, but this has never been demonstrated directly in vivo. N-acetylaspartate (NAA), a compound that is readily measured in vivo using proton magnetic resonance spectroscopy, can be used as a surrogate marker for neuronal loss or sublethal injury. To determine whether riluzole reverses sublethal corticomotoneuron damage in patients with ALS we measured NAA/creatine (Cr) relative intensity ratios in the motor cortex before and after treatment with riluzole 50 mg bid. After 3 weeks of riluzole therapy in 11 patients NAA/Cr increased from 2.14 ± 0.26 to 2.27 ± 0.24 (p = 0.044), whereas, in 12 untreated patients NAA/Cr decreased from 2.17 ± 0.20 to 2.08 ± 0.20 (p = 0.099). Thus the change in NAA/Cr between the treated and untreated groups was 0.22 ± 0.095 (p = 0.008). The magnitude of increase in NAA/Cr in those treated was not correlated with age, sex, duration of treatment or disease, the presence of probable or definite upper motor neuron (UMN) signs, bulbar features, or pre-treatment NAA/Cr. We conclude that magnetic resonance spectroscopy can provide a novel surrogate measure of neuronal integrity that demonstrates reversal of sublethal UMN injury in patients with ALS within weeks of initiating riluzole therapy.

Short‐term dichloroacetate treatment improves indices of cerebral metabolism in patients with mitochondrial disorders

Article abstract—We performed a short-term, double-blind, placebo-controlled, crossover trial of sodium dichloroacetate (DCA) therapy in 11 patients affected by various primary mitochondrial disorders. Independent measures of ox-idative metabolism (venous blood metabolites, exercise testing, phosphorus magnetic resonance [MR] spectroscopy of muscle, and proton MR spectroscopy of brain) were used in order to monitor metabolic responses to the drug. One week of DCA treatment produced significant decreases (p < 0.05) in blood lactate, pyruvate, and alanine at rest and after bicycle exercise. Proton MR spectra collected from a supraventricular volume of interest in brain of seven of ll patients also showed significant changes. Brain lactatekreatine ratio decreased by 42% during DCA treatment (p < 0.05). Brain cholinelcreatine ratio (which is low in patients with myelinopathies) increased by 18% (p < 0.01) after therapy. N-Acetylaspartatelcreatine ratio (an index of neuronal damage or loss) increased by 8% after treatment (p < 0.05). Proton MR spectra collected in two of 11 patients from a volume of interest including the basal ganglia showed similar results (decrease of 36.6% in lactatekreatine; increases of 16% in cholinelcreatine and 4.5% in N-acetylaspartatelcreatine). Phosphorus MR spectroscopy of muscle and self-assessed clinical disability were unchanged. Our study indicates that short-term DCA treatment not only lowers blood lactate but also improves indices of both brain oxidative metabolism and neuronal and glial density or function.

Effects of aerobic training in patients with mitochondrial myopathies

We studied the physiologic adaptation of patients with mitochondrial myopathies to aerobic training. Ten patients underwent individually supervised, moderate-intensity aerobic training on a treadmill for 8 weeks. Biochemical and functional measures improved with training. Estimated aerobic capacity increased by 30%. Blood lactate concentrations at rest and after exercise decreased by 30%. Muscle phosphorus magnetic resonance spectroscopy measurements of adenosine diphosphate recovery after exercise improved by more than 60%. Fatigue and tolerance to daily activities also improved. Although the improvement in exercise tolerance may be due in part to reversal of the effects of secondary deconditioning, this uncontrolled clinical trial suggests that aerobic training can benefit patients with mitochondrial myopathies.

Phase II/III randomized trial of TCH346 in patients with ALS

Background: TCH346 exerts antiapoptotic effects by binding to glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and blocking the apoptotic pathway in which GAPDH is involved. Apoptosis is considered to be a key pathogenic mechanism in neurodegenerative diseases including ALS. Methods: Patients were randomly assigned in a double-blind fashion to receive either placebo or one of four doses of TCH346 (1.0, 2.5, 7.5, or 15 mg/day) administered orally once daily for at least 24 weeks. The primary outcome measure was the rate of change in the revised ALS functional rating scale (ALSFRS-R). The trial design included a 16-week lead-in phase to determine each patients rate of disease progression. The between treatment comparison was adjusted for the individual pretreatment rates of progression. The study was powered to detect a 25% reduction in the rate of decline of the ALSFRS-R as compared with placebo. Secondary outcome measures included survival, pulmonary function, and manual muscle testing (MMT). Results: Five hundred ninety-one patients were enrolled at 42 sites in Europe and North America. There were no differences in baseline variables. There were no significant differences between placebo and active treatment groups in the mean rate of decline of the ALSFRS-R or in the secondary outcome measures (survival, pulmonary function, and MMT). Conclusion: The trial revealed no evidence of a beneficial effect of TCH346 on disease progression in patients with ALS.

A prospective, randomized, placebo‐controlled evaluation of corticoneuronal response to intrathecal BDNF therapy in ALS using magnetic resonance spectroscopy: feasibility and results

During the multicenter, phase III trial of intrathecal BDNF in ALS, we evaluated the neuronal marker N‐acetylaspartate (NAA) as a surrogate marker of therapeutic efficacy using proton magnetic resonance spectroscopic imaging (MRSI) in a prospective and blinded manner. Selected subjects tolerated the study well without pump malfunction. The NAA to creatine (Cr) intensity ratio (NAA/Cr) was measured in the precentral and postcentral gyri, the superior parietal lobule, the supplementary motor area, and the premotor cortex. After 4.5±0.6 weeks treatment, NAA/Cr did not change significantly in any of the regions in the BDNF‐treated group (n=5) compared to the placebo group (n=6). The lack of change in NAA correlated with the lack of clinical efficacy and supports the validity of NAA/Cr as a surrogate in this setting. MRSI is a feasible and safe method to evaluate intrathecal therapies in ALS.

Combined aerobic training and dichloroacetate improve exercise capacity and indices of aerobic metabolism in muscle cytochrome oxidase deficiency

There is no generally effective therapy for mitochondrial myopathies.In this study, we measured responses to combined aerobic training and oral dichloroacetate (DCA) therapy in a 25-year-old woman with a mitochondrial myopathy caused by cytochrome oxidase deficiency. The patient trained for 14 weeks, and DCA therapy was begun after 8 weeks. Independent indices of aerobic capacity and oxidative metabolism showed substantial improvement. Venous lactate concentrations at rest, and after a constant amount of work, decreased by approximately 50% after 8 weeks of aerobic training, and by more than 70% with the combination of training and DCA treatment. Heart rate at rest and after a constant amount of submaximal work decreased progressively. Aerobic capacity on a graded submaximal exercise test improved by 71% from baseline by the end of the treatment period.31 P magnetic resonance spectroscopy measurements of rate constants for recovery of muscle phosphocreatine increased 1.7-fold and metabolically active adenine diphosphate increased 2.8-fold after 8 weeks of training alone, and 4.5-fold and 23.0-fold after 14 weeks of training plus DCA treatment. Responses to the SF-36 Health Survey suggested a marked reduction in handicap. Thus, in this open study of a patient with cytochrome oxidase deficiency, a combination of aerobic training and DCA treatment resulted in substantial improvements in biochemical indices, exercise performance, and handicap. We conclude that exercise limitation in patients with mitochondrial myopathy may arise from effects of chronic deconditioning in addition to the effects of primary mitochondrial dysfunction and may be partially reversed by training and administration of DCA. NEUROLOGY 1996;47: 529-534

Characterization of the mitochondrial DNA abnormalities in the skeletal muscle of patients with inclusion body myositis

Inclusion body myositis (IBM) is a late-onset inflammatory myopathy with distinctive clinical and histopathological features. The molecular basis for the disease remains unknown, but abnormal nuclear morphology and the accumulation of a protein that binds single-stranded DNA in a sequence-independent fashion suggest a nuclear defect. Evidence of mitochondrial respiratory chain dysfunction (ragged-red fibers, multiple mtDNA deletions) has been reported in IBM muscle. Here we have investigated the relationship of the mtDNA abnormalities in sporadic and familial IBM patients to the pathogenesis of the disease. In situ hybridization analysis with mtDNA probes revealed several different mtDNA abnormalities in cytochrome c oxidase-negative muscle fibers including large-scale mtDNA deletions and mtDNA depletion, but no evidence for nonspecific DNA binding. Contrary to previous reports, we did not observe mtDNA deletions on Southern blot analysis, consistent with the presence of multiple different deleted mtDNA species demonstrated by single fiber PCR. There was no consistent correlation between the mitochondrial abnormalities and markers of muscle regeneration, inflammation, or microscopically detectable pathological alterations of myonuclei in the same fibers. Thus, early molecular abnormalities in IBM may simply accelerate the accumulation of mtDNA abnormalities that occurs with natural aging.

Western ALS study group

As a prelude to carrying out ALS clinical trials, our Western ALS (WALS) study group carried out a natural history study of 167 ALS patients using 42 strength and functional efficacy assessments at monthly intervals at 5 centers. The results demonstrated that declining pulmonary function correlated closely with death. The study also highlighted the variability in measurements and the importance of vigorous training and monitoring.

A multi-center screening trial of rasagiline in patients with amyotrophic lateral sclerosis: Possible mitochondrial biomarker target engagement

Rasagiline, a monoamine oxidase B inhibitor, slowed disease progression in the SOD1 mouse, and in a case series of patients with amyotrophic lateral sclerosis (ALS). Here we determine whether rasagiline is safe and effective in ALS compared to historical placebo controls, and whether it alters mitochondrial biomarkers. We performed a prospective open-label, multicenter screening trial of 36 ALS patients treated with 2 mg oral rasagiline daily for 12 months. Outcomes included the slope of deterioration of the revised ALS Functional Rating Scale (ALSFRS-R), adverse event monitoring, time to treatment failure, and exploratory biomarkers. Participants experienced no serious drug-related adverse events, and the most common adverse event was nausea (11.1%). Rasagiline did not improve the rate of decline in the ALSFRS-R; however, differences in symptom duration compared to historical placebo controls differentially affected ALSFRS-R slope estimates. Rasagiline changed biomarkers over 12 months, such that the mitochondrial membrane potential increased (JC-1 red/green fluorescent ratio 1.92, p = 0.0001) and apoptosis markers decreased (Bcl-2/Bax ratio 0.24, p < 0.0001). In conclusion, engagement of exploratory biomarkers and questions about comparability of baseline characteristics lead us to recommend a further placebo-controlled trial.

Correspondence Regarding: TDP-43 Proteinopathy and Motor Neuron Disease in Chronic Traumatic Encephalopathy. J Neuropathol Exp Neurol 2010:69;918-29

We read with interest the recent article “TDP-43 proteinopathy and motor neuron disease in chronic traumatic encephalopathy” by McKee et al (1). As neuromuscular specialists who care for large numbers of patients with amyotrophic lateral sclerosis (ALS), we have concerns about the conclusions drawn from 3 cases diagnosed as having ALS in life, while having histologic changes of both ALS and chronic traumatic encephalopathy (CTE) at autopsy. In their 12-paragraph discussion section and subsequent New York Times interview (2), the authors propose a cascade of events starting with head trauma, leading to TDP-43 proteinopathy, and ultimately to various clinical phenotypes including motor neuron disease. In support of this, they state, “… of all the putative environmental risk factors, trauma to the CNS emerges as one of the strongest and most consistent contenders for initiating the molecular cascades that result in ALS.” In actuality, the data linking trauma to ALS are significantly …