Nazem Atassi

Increased in vivo glial activation in patients with amyotrophic lateral sclerosis: Assessed with [11C]-PBR28

Evidence from human post mortem, in vivo and animal model studies implicates the neuroimmune system and activated microglia in the pathology of amyotrophic lateral sclerosis. The study aim was to further evaluate in vivo neuroinflammation in individuals with amyotrophic lateral sclerosis using [11C]-PBR28 positron emission tomography. Ten patients with amyotrophic lateral sclerosis (seven males, three females, 38–68 years) and ten age- and [11C]-PBR28 binding affinity-matched healthy volunteers (six males, four females, 33–65 years) completed a positron emission tomography scan. Standardized uptake values were calculated from 60 to 90 min post-injection and normalized to whole brain mean. Voxel-wise analysis showed increased binding in the motor cortices and corticospinal tracts in patients with amyotrophic lateral sclerosis compared to healthy controls (pFWE < 0.05). Region of interest analysis revealed increased [11C]-PBR28 binding in the precentral gyrus in patients (normalized standardized uptake value = 1.15) compared to controls (1.03, p < 0.05). In patients those values were positively correlated with upper motor neuron burden scores (r = 0.69, p < 0.05), and negatively correlated with the amyotrophic lateral sclerosis functional rating scale (r = –0.66, p < 0.05). Increased in vivo glial activation in motor cortices, that correlates with phenotype, complements previous histopathological reports. Further studies will determine the role of [11C]-PBR28 as a marker of treatments that target neuroinflammation.

Inflammation, Homocysteine, and Vitamin B6 Status After Ischemic Stroke

Background and Purpose— Epidemiological studies have described an association between low vitamin B6 (measured as pyridoxal 5′-phosphate [PLP]) and ischemic stroke, independent of homocysteine (tHcy). We investigated B6 status, tHcy, and inflammation (measured by C-reactive protein [CRP]) in patients with stroke and controls. Methods— Consecutive cases with new ischemic stroke were compared with matched controls. Fasting tHcy, PLP, and CRP were measured. Results— The adjusted odds ratio of low PLP in the highest compared with the lowest CRP quartile was 16.6 (2, 139.9, P =0.01). Age, CRP, supplemental vitamin use, and albumin were independent predictors of PLP (P <0.05 for all). No relationship was observed between CRP and tHcy. Conclusion— The relationship between inflammation and low B6 status may partially explain the findings of previous epidemiological studies.

The PRO-ACT database Design, initial analyses, and predictive features

Objective: To pool data from completed amyotrophic lateral sclerosis (ALS) clinical trials and create an open-access resource that enables greater understanding of the phenotype and biology of ALS. Methods: Clinical trials data were pooled from 16 completed phase II/III ALS clinical trials and one observational study. Over 8 million de-identified longitudinally collected data points from over 8,600 individuals with ALS were standardized across trials and merged to create the Pooled Resource Open-Access ALS Clinical Trials (PRO-ACT) database. This database includes demographics, family histories, and longitudinal clinical and laboratory data. Mixed effects models were used to describe the rate of disease progression measured by the Revised ALS Functional Rating Scale (ALSFRS-R) and vital capacity (VC). Cox regression models were used to describe survival data. Implementing Bonferroni correction, the critical p value for 15 different tests was p = 0.003. Results: The ALSFRS-R rate of decline was 1.02 (±2.3) points per month and the VC rate of decline was 2.24% of predicted (±6.9) per month. Higher levels of uric acid at trial entry were predictive of a slower drop in ALSFRS-R (p = 0.01) and VC (p < 0.0001), and longer survival (p = 0.02). Higher levels of creatinine at baseline were predictive of a slower drop in ALSFRS-R (p = 0.01) and VC (p < 0.0001), and longer survival (p = 0.01). Finally, higher body mass index (BMI) at baseline was associated with longer survival (p < 0.0001). Conclusion: The PRO-ACT database is the largest publicly available repository of merged ALS clinical trials data. We report that baseline levels of creatinine and uric acid, as well as baseline BMI, are strong predictors of disease progression and survival.

Depression in amyotrophic lateral sclerosis

Abstract Depression is an under-recognized comorbidity associated with amyotrophic lateral sclerosis (ALS). The goals of this study were to prospectively estimate the prevalence of depression and other ALS related symptoms and to study the impact of depression on enrollment in research studies. One hundred and twenty-seven people with ALS completed the ALS Depression Inventory (ADI-12) and answered questions about ALS related symptoms and research study enrollment preferences. Demographics, ALS symptoms, medications, functional status, and research enrollment were compared between depressed and non-depressed patients. Results showed that the prevalence of mild and severe depression was 29% and 6%, respectively. More than one-third of our ALS patients were receiving anti-depressants to treat depression, sialorrhea, and pseudobulbar affect. Depression prevalence was not correlated with disease duration or progression. Except for anxiety, none of the ALS related symptoms predicted depression. The presence of depression did not have an effect on the decision to enroll in research studies. In conclusion, major depression is less common in our ALS cohort than in the general population. The diagnosis of depression can be masked by some ALS related symptoms and it has no impact on enrollment in ALS clinical trials.

Diagnostic timelines and delays in diagnosing amyotrophic lateral sclerosis (ALS)

Abstract The objective of this study was to characterize the diagnostic timelines and their predictors in people with amyotrophic lateral sclerosis (ALS). Patients were identified through ALS billing codes. Time from presenting symptom to first doctor visit, first doctor visit to suspected ALS diagnosis, suspected to confirmed ALS diagnosis, and presenting symptom to confirmed ALS diagnosis (total diagnostic time) were collected. Regression models were used to analyze the predictors of diagnostic delay. Three hundred and four ALS patients were included in the analysis. Median total diagnostic time was 11.5 months. Diagnostic timelines were longer in patients with age > 60 years (p < 0.001), sporadic ALS (p = 0.043), and limb onset (p = 0.010). The presence of fasciculations, slurred speech, and lower extremity weakness when symptoms were first noted were independent predictors of shorter time to ALS diagnosis (p = 0.04, p = 0.02, and p = 0.04, respectively). About half of the patients (52%) received an alternative diagnosis and each patient saw an average of three different physicians before ALS diagnosis was confirmed. In conclusion, diagnostic timelines in ALS are long, and patients see many physicians and receive multiple alternative diagnoses before the diagnosis of ALS is confirmed. Older age, sporadic disease, and limb onset can delay ALS diagnosis.

Transplantation of spinal cord–derived neural stem cells for ALS Analysis of phase 1 and 2 trials

Objective: To test the safety of spinal cord transplantation of human stem cells in patients with amyotrophic lateral sclerosis (ALS) with escalating doses and expansion of the trial to multiple clinical centers. Methods: This open-label trial included 15 participants at 3 academic centers divided into 5 treatment groups receiving increasing doses of stem cells by increasing numbers of cells/injection and increasing numbers of injections. All participants received bilateral injections into the cervical spinal cord (C3-C5). The final group received injections into both the lumbar (L2-L4) and cervical cord through 2 separate surgical procedures. Participants were assessed for adverse events and progression of disease, as measured by the ALS Functional Rating Scale–Revised, forced vital capacity, and quantitative measures of strength. Statistical analysis focused on the slopes of decline of these phase 2 trial participants alone or in combination with the phase 1 participants (previously reported), comparing these groups to 3 separate historical control groups. Results: Adverse events were mostly related to transient pain associated with surgery and to side effects of immunosuppressant medications. There was one incident of acute postoperative deterioration in neurologic function and another incident of a central pain syndrome. We could not discern differences in surgical outcomes between surgeons. Comparisons of the slopes of decline with the 3 separate historical control groups showed no differences in mean rates of progression. Conclusions: Intraspinal transplantation of human spinal cord–derived neural stem cells can be safely accomplished at high doses, including successive lumbar and cervical procedures. The procedure can be expanded safely to multiple surgical centers. Classification of evidence: This study provides Class IV evidence that for patients with ALS, spinal cord transplantation of human stem cells can be safely accomplished and does not accelerate the progression of the disease. This study lacks the precision to exclude important benefit or safety issues.

A phase I, pharmacokinetic, dosage escalation study of creatine monohydrate in subjects with amyotrophic lateral sclerosis

Abstract Creatine monohydrate (creatine) has potential neuroprotective properties and is a commonly used supplement in amyotrophic lateral sclerosis (ALS) and other neurodegenerative disorders. Minimum therapeutic and maximum tolerated dosages of creatine are not yet known, nor is it known what systemic plasma concentrations result from specific dosage regimens. The objectives of this study were to establish steady-state plasma pharmacokinetics of creatine at several dosages, and to evaluate the effects of creatine on brain metabolites using proton magnetic resonance spectroscopy (1H-MRS). Six participants with ALS received creatine at three weekly escalating oral dosages (5, 10, and 15 g b.i.d.). Plasma creatine levels and MR spectra were obtained at baseline and with each dosage increase. Mean pre-dose steady-state creatine plasma concentrations were 20.3, 39.3, and 61.5 ug/ml at 5, 10, and 15 g b.i.d., respectively. Creatine spectra increased by 8% (p = 0.06) and glutamate + glutamine signals decreased by 17% (p = 0.039) at higher dosages. There were no safety concerns at any of the dosages. In conclusion, creatine plasma concentrations increased in a dose-dependent manner. Creatine appears to cross the blood-brain barrier, and oral administration of 15 g b.i.d. is associated with increased in vivo brain creatine concentrations and decreased glutamate concentrations.

A randomized trial of mexiletine in ALS: Safety and effects on muscle cramps and progression.

Objective: To determine the safety and tolerability of mexiletine in a phase II double-blind randomized controlled trial of sporadic amyotrophic lateral sclerosis (SALS). Methods: Sixty participants with SALS from 10 centers were randomized 1:1:1 to placebo, mexiletine 300 mg/d, or mexiletine 900 mg/d and followed for 12 weeks. The primary endpoints were safety and tolerability. Secondary endpoints were pharmacokinetic study from plasma and CSF, ALS Functional Rating Scale–Revised (ALSFRS-R) score, slow vital capacity (SVC), and muscle cramp frequency and severity. Results: The only serious adverse event among active arm participants was one episode of imbalance. Thirty-two percent of participants receiving 900 mg of mexiletine discontinued study drug vs 5% on placebo (p = 0.026). Pharmacokinetic study demonstrated a peak plasma concentration 2 hours postdose and strong correlation between plasma and CSF (p < 0.001). Rates of decline of ALSFRS-R and SVC did not differ from placebo. Analysis of all randomized patients demonstrated significant reductions of muscle cramp frequency (300 mg: rate = 31% of placebo, p = 0.047; 900 mg: 16% of placebo, p = 0.002) and cramp intensity (300 mg: mean = 45% of placebo, p = 0.08; 900 mg: 25% of placebo, p = 0.005). Conclusions: Mexiletine was safe at both doses and well-tolerated at 300 mg/d but adverse effects at 900 mg/d led to a high rate of discontinuation. Mexiletine treatment resulted in large dose-dependent reductions in muscle cramp frequency and severity. No effect on rate of progression was detected, but clinically important differences could not be excluded in this small and short-duration study. Classification of evidence: This study provides Class I evidence that mexiletine is safe when given daily to patients with amyotrophic lateral sclerosis at 300 and 900 mg and well-tolerated at the lower dose.

ALS biomarkers for therapy development: State of the field and future directions

Biomarkers have become the focus of intense research in the field of amyotrophic lateral sclerosis (ALS), with the hope that they might aid therapy development efforts. Notwithstanding the discovery of many candidate biomarkers, none have yet emerged as validated tools for drug development. In this review we present a nuanced view of biomarkers based on the perspective of the Food and Drug Administration; highlight the distinction between discovery and validation; describe existing and emerging resources; review leading biological fluid‐based, electrophysiological, and neuroimaging candidates relevant to therapy development efforts; discuss lessons learned from biomarker initiatives in related neurodegenerative diseases; and outline specific steps that we, as a field, might take to hasten the development and validation of biomarkers that will prove useful in enhancing efforts to develop effective treatments for ALS patients. Most important among these is the proposal to establish a federated ALS Biomarker Consortium in which all interested and willing stakeholders may participate with equal opportunity to contribute to the broader mission of biomarker development and validation. Muscle Nerve 53: 169–182, 2016

Glial activation colocalizes with structural abnormalities in amyotrophic lateral sclerosis

Objective: In this cross-sectional study, we aimed to evaluate brain structural abnormalities in relation to glial activation in the same cohort of participants. Methods: Ten individuals with amyotrophic lateral sclerosis (ALS) and 10 matched healthy controls underwent brain imaging using integrated MR/PET and the radioligand [11C]-PBR28. Diagnosis history and clinical assessments including Upper Motor Neuron Burden Scale (UMNB) were obtained from patients with ALS. Diffusion tensor imaging (DTI) analyses including tract-based spatial statistics and tractography were applied. DTI metrics including fractional anisotropy (FA) and diffusivities (mean, axial, and radial) were measured in regions of interest. Cortical thickness was assessed using surface-based analysis. The locations of structural changes, measured by DTI and the areas of cortical thinning, were compared to regional glial activation measured by relative [11C]-PBR28 uptake. Results: In this cohort of individuals with ALS, reduced FA and cortical thinning colocalized with regions demonstrating higher radioligand binding. [11C]-PBR28 binding in the left motor cortex was correlated with FA (r = −0.68, p < 0.05) and cortical thickness (r = −0.75, p < 0.05). UMNB was correlated with glial activation (r = +0.75, p < 0.05), FA (r = −0.77, p < 0.05), and cortical thickness (r = −0.75, p < 0.05) in the motor cortex. Conclusions: Increased uptake of the glial marker [11C]-PBR28 colocalizes with changes in FA and cortical thinning. This suggests a link between disease mechanisms (gliosis and inflammation) and structural changes (cortical thinning and white and gray matter changes). In this multimodal neuroimaging work, we provide an in vivo model to investigate the pathogenesis of ALS.