Serum urate at trial entry and ALS progression in EMPOWER.

Our objective was to determine whether serum urate predicts ALS progression. A study population comprised adult participants of EMPOWER (n = 942), a phase III clinical trial to evaluate the efficacy of dexpramipexole to treat ALS. Urate was measured in blood samples collected during enrollment as part of the routine block chemistry. We measured outcomes by combined assessment of function and survival rank (CAFs), and time to death, by 12 months. Results showed that in females there was not a significant relation between urate and outcomes. In males, outcomes improved with increasing urate (comparing highest to lowest urate quartile: CAFS was 53 points better with p for trend = 0.04; and hazard ratio for death was 0.60 with p for trend = 0.07), but with adjustment for body mass index (BMI) at baseline, a predictor of both urate levels and prognosis, associations were attenuated and no longer statistically significant. Overall, participants with urate levels equal to or above the median (5.1 mg/dl) appeared to have a survival advantage compared to those below (hazard ratio adjusted for BMI: 0.67; 95% confidence interval 0.47-0.95). In conclusion, these findings suggest that while the association between urate at baseline and ALS progression is partially explained by BMI, there may be an independent beneficial effect of urate.

Task-related fMRI responses to a nicotinic acetylcholine receptor partial agonist in schizophrenia: A randomized trial.

INTRODUCTION: AQW051, an α7-nicotinic acetylcholine receptor partial agonist, enhanced cognitive function in rodent models of learning and memory. This study evaluated brain activation during performance of a working memory task (WMT) and an episodic memory task (EMT), and the effect of AQW051 on task-related brain activation and performance in subjects with schizophrenia. METHODS: This was a double-blind, randomized, placebo-controlled, multicenter, 2-period cross-over trial (NCT00825539) in participants with chronic, stable schizophrenia. Participants, stratified according to smoking status, were randomized (1:1:1:1:1:1) to 1 of 6 sequence groups that determined the study drug dose (AQW051 7.5mg, 50mg or 100mg) and order of administration versus placebo. The primary outcome was brain activation in a priori target regions of interest (ROIs) during performance of the WMT and EMT, measured using functional magnetic resonance imaging. The effect of AQW051 on task-related (EMT and WMT) brain activation and performance was also assessed, as were safety and tolerability. RESULTS: Overall, 60 of 68 enrolled participants completed the study (AQW051 then placebo: 7.5mg n=9; 50mg n=11; 100mg n=10. Placebo then AQW051: 7.5mg n=10; 50mg n=11; 100mg n=9). Significant task-related brain activation (5% significance level) was observed with placebo. During the WMT, a medium effect size was observed in the inferior prefrontal cortex with AQW051 100mg versus placebo (0.431; p=0.105). During the EMT encoding phase, a large effect size was observed in the anterior hippocampus (0.795; p=0.007) and a medium effect size in the posterior hippocampus (0.476; p=0.079) with AQW051 7.5mg. No other medium/large effect sizes were observed with any dose on either task. Effects on brain activation were generally not associated with changes in cognitive performance. AQW051 was well tolerated with an acceptable safety profile. CONCLUSIONS: Overall, no consistent effects of AQW051 on brain regions involved in the performance of a WMT or EMT were observed; however, this study presents a model for evaluating potential response to pharmacological interventions for cognitive impairment in schizophrenia.

Quantitative strength testing in ALS clinical trials.

OBJECTIVE: To study the attributes of quantitative strength testing using hand-held dynamometry (HHD) as an efficacy measure in 2 large phase 3 amyotrophic lateral sclerosis (ALS) trials. METHODS: In the phase 3 trials of ceftriaxone and dexpramipexole, 513 and 943 patients, respectively, were enrolled in double-blind, randomized, placebo-controlled trials with planned follow-up of at least 1 year. Patients were studied every 3 months in the ceftriaxone study and every 2 months in the dexpramipexole study. Evaluators of HHD were trained and had to show evidence of adequate performance of strength testing; the testing paradigm involved testing 9 muscle groups in the upper and lower extremity bilaterally. Neither drug significantly affected any outcome measure. Strength measurements were evaluated by individual muscle and by megascores, which averaged scaled strength measures to produce an overall measure of muscle strength. RESULTS: A measure combining rate of decline with both within- and between-patient variabilities of measurement, the coefficient of variation for rate of change, was calculated, and showed that HHD overall performed slightly less well than Amyotrophic Lateral Sclerosis Functional Rating Scale-revised (ALSFRS-R) but better than vital capacity. Individual muscles were highly correlated to the identical muscles on the contralateral side, as well as to other muscles in the same body region. Strength decline was correlated both with ALSFRS-R and vital capacity. CONCLUSION: Quantitative strength testing using HHD is a reliable and reproducible measure of decline in ALS.

Activity of secukinumab, an anti-IL-17A antibody, on brain lesions in RRMS: results from a randomized, proof-of-concept study.

The objective of this study was to assess the effect of secukinumab, a monoclonal antibody that inhibits interleukin (IL)-17A, on number of new active brain magnetic resonance imaging (MRI) lesions in subjects with relapsing-remitting multiple sclerosis (MS). Subjects (N = 73) were randomized 1:1 to secukinumab 10 mg/kg or placebo by intravenous infusion at weeks 0, 2, 4, 8, 12, 16, and 20. MRI scans were obtained within 30 days prior to randomization, on a monthly basis during the treatment period, and at study completion. The primary endpoint was the cumulative number of combined unique active lesions (CUAL) observed on brain MRI scans from week 4 to week 24. Compared with placebo, secukinumab non-significantly reduced the number of CUAL observed on 4-weekly MRI from week 4 to 24 (primary endpoint) by 49 % (95 % CI -10 to 77 %; P = 0.087) and significantly reduced the number of cumulative new gadolinium-enhancing T1 lesions by 67 % (31-84 %, P = 0.003). CUAL reductions were progressively greater from week 4 (1 %) to week 16 (49 %) and persisted until end-study (50 %). There were no serious adverse events; the adverse event rate was comparable to placebo (53 versus 49 %), although mild-to-moderate infection was somewhat more frequent (37 versus 23 %). This proof-of-concept study provides the first evidence that blocking IL-17A with an antibody may reduce MRI lesion activity in MS. Further studies are needed to confirm this finding and determine the magnitude of effect.

Metabotropic glutamate receptor type 5 in levodopa-induced motor complications.

Metabotropic glutamate receptors type 5 (mGluR5) are implicated in regulation of synaptic plasticity and learning, and were the focus of our investigation in human Parkinson's disease (PD) patients with dyskinesias and wearing-off, and in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) monkeys with dyskinesias. Using the selective mGluR5 ligand [(3)H]ABP688 autoradiography, we measured mGluR5 in brain slices from 11 normal and 14 PD patients and from MPTP monkeys, in relation to motor complications (dyskinesias and wearing-off) associated with treatment with l-dopa. In 16 monkeys with a bilateral MPTP lesion and four controls, [(3)H]ABP688 specific binding was elevated in the striatum of dyskinetic l-dopa-treated MPTP monkeys but not in MPTP monkeys without dyskinesias compared to controls. PD patients with motor complications (either dyskinesias or wearing-off) had higher [(3)H]ABP688 specific binding compared to those without motor complications and controls in putamen, external and internal globus pallidus. Elevated glutamatergic transmission as measured with increased mGluR5 specific binding was associated with motor complications and its antagonism could be targeted for their treatment.

Somatic mitochondrial DNA mutations in single neurons and glia.

Somatic mitochondrial DNA (mtDNA) point mutations reach high levels in the brain. However, the cell types that accumulate mutations and the patterns of mutations within individual cells are not known. We have quantified somatic mtDNA mutations in 28 single neurons and in 18 single glia from post-mortem human substantia nigra of six control subjects. Both neurons and glia contain mtDNA with somatic mutations. Single neurons harbor a geometric mean (95% CI) of 200.3 (152.9-262.4) somatic mtDNA point mutations per million base pairs, compared to 133.8 (97.5-184.9) for single glia (p=0.0251). If mutations detected multiple times in the same cell are counted only once, the mean mutation level per million base pairs remains elevated in single neurons (146.9; 124.0-174.2) compared to single glia (100.5; 81.5-126.5; p=0.009). Multiple distinct somatic point mutations are present in different cells from the same subject. Most of these mutations are individually present at low levels (less than 10-20% of mtDNA molecules), but with high aggregate mutation levels, particularly in neurons. These mutations may contribute to changes in brain function during normal aging and neurodegenerative disorders.

Attenuation of free radical production and paracrystalline inclusions by creatine supplementation in a patient with a novel cytochrome b mutation.

Mitochondrial cytopathies are associated with increased free radical generation and paracrystalline inclusions. Paracrystalline inclusions were serendipitously found in a young male athlete with a very high respiratory exchange ratio during steady-state exercise; he also had an unusually low aerobic capacity. Direct sequencing of the mitochondrial DNA (mtDNA) coding regions revealed a novel missense mutation (G15497A) resulting in a glycine-->serine conversion at a highly conserved site in the cytochrome b gene in the subject, his mother, and sister. Cybrids, prepared by fusion of the subject's platelets with either U87MG rho degrees or SH-SY5Y rho degrees cells, generated higher basal levels of reactive oxygen species (ROS), had a lower adenosine triphosphate (ATP) content, and were more sensitive to oxygen and glucose deprivation and peroxynitrite generation compared to control cybrids with wild-type mtDNA. Cell survival was significantly enhanced with 50 mmol/L creatine monohydrate (CM) administration. The subject was also treated with CM (10 g/d) for a period of 5 weeks and a repeat muscle biopsy showed no paracrystalline inclusions. The results suggest that the development of exercise-induced paracrystalline inclusions may be influenced by the G15497A mtDNA mutation, and that CM mitigates against the pathological consequences of this mutation.

Somatic mitochondrial DNA mutations in cortex and substantia nigra in aging and Parkinson's disease.

Oxidative damage to mitochondrial DNA (mtDNA) increases with age in the brain and can induce G:C to T:A and T:A to G:C point mutations. Though rare at any particular site, multiple somatic mtDNA mutations induced by oxidative damage or by other mechanisms may accumulate with age in the brain and thus could play a role in aging and neurodegenerative diseases. However, no prior study has quantified the total burden of mtDNA point mutation subtypes in the brain. Using a highly sensitive cloning and sequencing strategy, we find that the aggregate levels of G:C to T:A and T:A to G:C transversions and of all point mutations increase with age in the frontal cortex (FCtx). In the substantia nigra (SN), the aggregate levels of point mutations in young controls are similar to the levels in the SN or FCtx of elderly subjects. Extrapolation from our data suggests an average of 2.7 (FCtx) to 3.2 (SN) somatic point mutations per mitochondrial genome in elderly subjects. There were no significant differences between Parkinson's disease (PD) patients and age-matched controls in somatic mutation levels. These results indicate that individually rare mtDNA point mutations reach a high aggregate burden in FCtx and SN of elderly subjects.

A heteroplasmic mitochondrial complex I gene mutation in adult-onset dystonia.

Mitochondrial DNA (mtDNA) mutations can cause rare forms of dystonia, but the role of mtDNA mutations in other types of dystonia is not well understood. We now report identification by sequencing, restriction endonuclease analyses, and clonal analyses of a heteroplasmic missense A to G base pair substitution at nucleotide position 3796 (A3796G) in the gene encoding the ND1 subunit of mitochondrial complex I in a patient with adult-onset dystonia, spasticity, and core-type myopathy. The mutation converts a highly conserved threonine to an alanine. The same mutation subsequently was identified in 2 of 74 additional unrelated adult-onset dystonia patients. A muscle biopsy was obtained from 1 of these 2 subjects and this revealed abnormalities of electron transport chain (ETC) activities. The mutation was absent in 64 subjects with early onset dystonia, 82 normal controls, and 65 subjects with Parkinson's disease or multiple system atrophy. The A3796G mutation previously has been reported in 3 of 226 subjects from mitochondrial haplogroup H. Each of the 3 subjects in our study harboring the A3796G mutation was also from haplogroup H. However, a subgroup analysis of haplogroup H subjects from our study indicates that the A3796G mutation is significantly overrepresented among haplogroup H adult-onset dystonia subjects compared with haplogroup H controls (P<0.01). This difference remains significant even after excluding the index patient (P=0.04). These data suggest that, among haplogroup H subjects, the presence of the A3796G mutation increases the risk of developing adult-onset dystonia.

Treatment of Leber's hereditary optic neuropathy: theory to practice.

Dramatic advances in our understanding of the molecular genetic basis of Leber's hereditary optic neuropathy (LHON) have revolutionized our ability to diagnose and prognosticate this disease. Unfortunately no corresponding advances in the treatment of LHON have emerged. Glaucoma is a prevalent form of optic neuropathy that has been studied extensively. Lessons learned from treatment of LHON and glaucoma may have important implications for both diseases. LHON presents formidable challenges to the design and conduct of clinical trials. The acutely symptomatic LHON patient with monocular vision loss provides a unique clinical situation in which to test an agent during a critical therapeutic window. Advances in neuroprotection, apoptosis, and neurodegenerative diseases may provide important clues for potential therapeutic agents for LHON. Antioxidants and agents that interfere with the critical steps of mitochondrial-dependent, oxidative stress-induced apoptosis are candidates for future LHON therapy. A variety of neuroprotective agents, under active investigation in other diseases, may be useful in LHON therapy. Effective pharmacotherapy will complement the current management approach that has changed little in the 130 years since LHON was originally described.