Lora Clawson

ABERRANT RNA PROCESSING IN A NEURODEGENERATIVE DISEASE : THE CAUSE FOR ABSENT EAAT2, A GLUTAMATE TRANSPORTER, IN AMYOTROPHIC LATERAL SCLEROSIS

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that is characterized by selective upper and lower motor neuron degeneration, the pathogenesis of which is unknown. About 60%-70% of sporadic ALS patients have a 30%-95% loss of the astroglial glutamate transporter EAAT2 (excitatory amino acid transporter 2) protein in motor cortex and spinal cord. Loss of EAAT2 leads to increased extracellular glutamate and excitotoxic neuronal degeneration. Multiple abnormal EAAT2 mRNAs, including intron-retention and exon-skipping, have now been identified from the affected areas of ALS patients. The aberrant mRNAs were highly abundant and were found only in neuropathologically affected areas of ALS patients but not in other brain regions. They were found in 65% of sporadic ALS patients but were not found in nonneurologic disease or other disease controls. They were also detectable in the cerebrospinal fluid (CSF) of living ALS patients, early in the disease. In vitro expression studies suggest that proteins translated from these aberrant mRNAs may undergo rapid degradation and/ or produce a dominant negative effect on normal EAAT2 resulting in loss of protein and activity. These findings suggest that the loss of EAAT2 in ALS is due to aberrant mRNA and that these aberrant mRNAs could result from RNA processing errors. Aberrant RNA processing could be important in the pathophysiology of neurodegenerative disease and in excitotoxicity. The presence of these mRNA species in ALS CSF may have diagnostic utility.

Serum antibodies to GM1 ganglioside in amyotrophic lateral sclerosis

We report the presence of serum antibodies directed against GM1 ganglioside, a defined neural antigen, in many patients with amyotrophic lateral sclerosis (ALS). We examined serum from a series of patients with well-documented clinical diagnoses. Serum antibodies to GM1 ganglioside were measured using ELIS A assays. Our results showed that polyclonal IgM anti-GM1 antibodies were present at dilutions of 1:25 to 1:2,000 in 42 of 74 (57%) patients with ALS. The anti-GM1 antibodies were especially frequent in patients with prominent lower motor neuron signs (41/59; 69%). Few normal controls (2/23) and motor-sensory neuropathy patients (3/27) had similar antibodies. Anti-GM1 antibodies did occur in patients with nonneural autoimmune disorders. However, the anti-GM1 antibodies in these patients tended to differ from those in ALS based on an analysis of their light chain types. Further examination of the role and spectrum of serum antiganglioside antibody activity in motor neuron syndromes is warranted.

Early use of non‐invasive ventilation prolongs survival in subjects with ALS

Non‐invasive positive pressure ventilation (NPPV) can improve survival in ALS patients with advanced respiratory impairment, but it is not known if it is beneficial earlier in the disease course. A retrospective cohort study of patients with ALS was performed comparing survival from time of diagnosis in subjects who started NPPV use when their FVC was ⩾65% predicted (Early NPPV) with subjects who started NPPV when their FVC was below 65% predicted (Standard NPPV). The Early group (n = 25) and the Standard group (n = 67) were similar except for pulmonary function (mean FVC in Early NPPV group = 74.3±10.1% predicted and 48.3±11.3 in Standard group, p<0.001). The median time from ALS diagnosis to death was significantly longer in the Early NPPV group (2.7 years vs. 1.8 years, p = 0.045). This remained significant after adjustment for potential confounding factors (H.R. = 0.55, 95% CI 0.31–0.98). Survival from time of diagnosis was nearly one year longer in the Early group. Until more definitive data are available from randomized trials, our findings suggest that clinicians either encourage earlier use of NPPV or use more sensitive tests for respiratory muscle impairment than upright FVC.

Hospitalization in amyotrophic lateral sclerosis Causes, costs, and outcomes

Objective: As ALS progresses, extensive supportive care is required, including multidisciplinary outpatient care and hospitalization. The authors studied the causes, health care utilization, and outcomes for hospitalized patients with ALS. Methods: With use of the 1996 Nationwide Inpatient Sample, an administrative database representing 20% of U.S. hospitals, 1,600 hospitalizations in patients with ALS were identified and compared with 5,364,728 non-ALS hospitalizations. Results: The most common concurrent diagnoses in patients with ALS were dehydration and malnutrition (574 patients, 36%), pneumonia (507 patients, 32%), and respiratory failure (398 patients, 25%). Only 38% of patients with ALS were discharged to home without home health care compared with 73% of patients with non-ALS. Fifteen percent of patients with ALS died in the hospital compared with 3% of non-ALS patients. The average length of hospital stay and charges were greater for patients with ALS than for non-ALS patients (8.4 days and

A phase II trial of talampanel in subjects with amyotrophic lateral sclerosis.

19,810 for ALS patients and 5.4 days and

Electrical impedance myography as a biomarker to assess ALS progression

11,924 for non-ALS patients). Mortality was significantly associated with emergency room admission (versus nonemergency admission; OR = 1.60), increasing age (per year; OR = 1.03), respiratory failure (OR = 3.37), and pneumonia (OR = 2.02) (p < 0.01 for all comparisons). Conclusions: Patients with ALS have lengthy and costly hospital admissions, a high in-hospital mortality rate, and few routine discharges. Recognition of the issues that precipitate hospitalization may allow development of preventive strategies.

High-dosage ascorbic acid treatment in charcot-marie-tooth disease type 1A results of a randomized, double-masked, controlled trial

Abstract Our objective was to determine if chronic treatment with the non-competitive AMPA antagonist talampanel is efficacious and safe in subjects with ALS. A double-blind, placebo-controlled, multicenter, randomized clinical trial of nine months treatment duration was conducted in 59 subjects with ALS, with 40 subjects receiving talampanel 50 mg p.o. t.i.d, and 19 subjects receiving placebo. Primary outcome measure was rate of decline in isometric arm strength (as measured by change in arm strength megaslope of the Tufts Quantitative Neuromuscular Exam (TQNE)). Other efficacy endpoints included rate of decline in respiratory function, isometric leg strength, bulbar function, fine motor function, the ALS Functional Rating Scale (ALSFRS), and survival. Secondary safety outcome measures were frequency of adverse events, neurological status, plasma concentration of talampanel, vital signs, routine laboratory tests, and electrocardiograms. Decline in muscle strength was 15% less in talampanel treated subjects, and decline in ALSFRS was 30% slower in talampanel treated subjects. Talampanel was safe in subjects with ALS. Mortality rates (8% talampanel, 5% placebo) and drug discontinuation rates (25% talampanel, 16% placebo) were similar in active treatment and placebo groups. Dizziness and somnolence occurred significantly more often in talampanel treated subjects. Although no efficacy measure reached statistical significance, there was a repeated trend toward slower decline in ALSFRS and isometric muscle strength in talampanel treated subjects. Talampanel was well tolerated in subjects with ALS. Although certain adverse events occurred more frequently in the active treatment group, the rate of subject drop-out after nine months did not exceed that seen in other trials. These findings provide strong support for a phase III trial to determine the efficacy of talampanel in subjects with ALS.

Amyotrophic lateral sclerosis: evaluation and treatment of respiratory impairment

Abstract Electrical impedance myography (EIM), a non-invasive, electrophysiological technique, has preliminarily shown value as an ALS biomarker. Here we perform a multicenter study to further assess EIM’s potential for tracking ALS. ALS patients were enrolled across eight sites. Each subject underwent EIM, handheld dynamometry (HHD), and the ALS Functional Rating Scale-revised (ALSFRS-R) regularly. Techniques were compared by assessing the coefficient of variation (CoV) in the rate of decline and each technique’s correlation to survival. Results showed that in the 60 patients followed for one year, EIM phase measured from the most rapidly progressing muscle in each patient had a CoV in the rate of decline of 0.62, compared to HHD (0.82) and the ALSFRS-R (0.74). Restricting the measurements to the first six months gave a CoV of 0.55 for EIM, 0.93 for HHD, and 0.84 for ALSFRS-R. For both time-periods, all three measures correlated with survival. Based on these data, a six-month clinical trial designed to detect a 20% treatment effect with 80% power using EIM would require only 95 patients/arm compared to the ALSFRS-R, which would require 220 subjects/arm. In conclusion, EIM can serve as a useful ALS biomarker that offers the prospect of greatly accelerating phase 2 clinical trials.

Promoting excellence in end‐of‐life care in ALS

IMPORTANCE No current medications improve neuropathy in subjects with Charcot-Marie-Tooth disease type 1A (CMT1A). Ascorbic acid (AA) treatment improved the neuropathy of a transgenic mouse model of CMT1A and is a potential therapy. A lower dosage (1.5 g/d) did not cause improvement in humans. It is unknown whether a higher dosage would prove more effective. OBJECTIVE To determine whether 4-g/d AA improves the neuropathy of subjects with CMT1A. DESIGN A futility design to determine whether AA was unable to reduce worsening on the CMT Neuropathy Score (CMTNS) by at least 50% over a 2-year period relative to a natural history control group. SETTING Three referral centers with peripheral nerve clinics (Wayne State University, Johns Hopkins University, and University of Rochester). PARTICIPANTS One hundred seventy-four subjects with CMT1A were assessed for eligibility; 48 did not meet eligibility criteria and 16 declined to participate. The remaining 110 subjects, aged 13 to 70 years, were randomly assigned in a double-masked fashion with 4:1 allocation to oral AA (87 subjects) or matching placebo (23 subjects). Sixty-nine subjects from the treatment group and 16 from the placebo group completed the study. Two subjects from the treatment group and 1 from the placebo group withdrew because of adverse effects. INTERVENTIONS Oral AA (4 g/d) or matching placebo. MAIN OUTCOMES AND MEASURES Change from baseline to year 2 in the CMTNS, a validated composite impairment score for CMT. RESULTS The mean 2-year change in the CMTNS was -0.21 for the AA group and -0.92 for the placebo group, both better than natural history (+1.33). This was well below 50% reduction of CMTNS worsening from natural history, so futility could not be declared (P > .99). CONCLUSIONS AND RELEVANCE Both treated patients and those receiving placebo performed better than natural history. It seems unlikely that our results support undertaking a larger trial of 4-g/d AA treatment in subjects with CMT1A. TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00484510.

Pulmonary predictors of survival in amyotrophic lateral sclerosis: Use in clinical trial design

Patients with amyotrophic lateral sclerosis (ALS) invariably develop respiratory muscle weakness and most die from pulmonary complications. There are numerous tests available to evaluate respiratory status in ALS and it is important to understand their various advantages and limitations. Forced vital capacity (FVC) is commonly used but can remain normal despite substantial inspiratory muscle weakness. Maximal pressures measured at the mouth are useful for excluding weakness if they are normal but are difficult to interpret if abnormal. Invasive testing, such as measurement of transdiaphragmatic pressure, provides an accurate measure of inspiratory strength but is not readily available and is not practical for serial measures. There are supportive respiratory techniques that have been shown to benefit patients with ALS. Clinicians should be familiar with these interventions, including mechanically assisted coughing, non-invasive ventilation and tracheostomy with mechanical ventilation. Observational studies have demonstrated improved survival and quality of life with noninvasive ventilation. Tracheostomy with long-term mechanical ventilation is not frequently used but can be an important component of care for ALS. This review describes an approach to respiratory evaluation and care of patients with ALS.