Faculty Bibliography

Microgliosis is a prominent pathological feature in many neurological diseases including multiple sclerosis (MS), a progressive auto-immune demyelinating disorder. The precise role of microglia, parenchymal central nervous system (CNS) macrophages, during demyelination, and the relative contributions of peripheral macrophages are incompletely understood. Classical markers used to identify microglia do not reliably discriminate between microglia and peripheral macrophages, confounding analyses. Here, we use a genetic fate mapping strategy to identify microglia as predominant responders and key effectors of demyelination in the cuprizone (CUP) model. Colony-stimulating factor 1 (CSF1), also known as macrophage colony-stimulating factor (M-CSF) - a secreted cytokine that regulates microglia development and survival-is upregulated in demyelinated white matter lesions. Depletion of microglia with the CSF1R inhibitor PLX3397 greatly abrogates the demyelination, loss of oligodendrocytes, and reactive astrocytosis that results from CUP treatment. Electron microscopy (EM) and serial block face imaging show myelin sheaths remain intact in CUP treated mice depleted of microglia. However, these CUP-damaged myelin sheaths are lost and robustly phagocytosed upon-repopulation of microglia. Direct injection of CSF1 into CNS white matter induces focal microgliosis and demyelination indicating active CSF1 signaling can promote demyelination. Finally, mice defective in adopting a toxic astrocyte phenotype that is driven by microglia nevertheless demyelinate normally upon CUP treatment implicating microglia rather than astrocytes as the primary drivers of CUP-mediated demyelination. Together, these studies indicate activated microglia are required for and can drive demyelination directly and implicate CSF1 signaling in these events.

Cell-free DNA (cfDNA) from cerebrospinal fluid (CSF) offers unique opportunities for genomic profiling of tumors involving the central nervous system but remains uncommonly used in clinical practice. We describe our clinical experience using cfDNA from CSF for routine molecular testing using Memorial Sloan Kettering Integrated Mutation Profiling of Actionable Cancer Targets (targeting 468 cancer-related genes). In all, 148 cfDNA samples were assessed, comparing results of cfDNA versus genomic DNA (gDNA; gDNA from cell pellets) derived from the same CSF sample and the primary tumor. Of these, 71.6% (106/148) were successfully sequenced. Somatic alterations (mutations and fusions) were observed in 70.8% (75/106) of the samples; 97.3% (73/75) comprised variants confirming central nervous system involvement by a previously diagnosed tumor, 14.7% (11/75) had additional variants consistent with a therapy-related resistance mechanism, and 2.7% (2/75) had variants that independently diagnosed a new primary. Among samples with paired cfDNA and gDNA sequencing results, cfDNA was more frequently positive for at least one mutation [43.6% (55/126) versus 19.8% (25/126)] and harbored 1.6× more mutations (6.94 versus 4.65; P = 0.005), with higher mean variant allele fractions (41.1% versus 13.0%; P < 0.0001). Among mutation-positive cfDNAs, the corresponding gDNA was frequently negative (44.6%; 25/55) or failed sequencing (17.8%; 9/55). Routine molecular profiling of cfDNA is superior to gDNA from CSF, facilitating the capture of mutations at high variant allele frequency, even in the context of a negative cytology.

Adolescents with anxiety disorders exhibit excessive emotional and somatic arousal. Neuroimaging studies have shown abnormal cerebral cortical activation and connectivity in this patient population. The specific role of cerebellar output circuitry, specifically the dentate nuclei (DN), in adolescent anxiety disorders remains largely unexplored. Resting-state functional connectivity analyses have parcellated the DN, the major output nuclei of the cerebellum, into three functional territories (FTs) that include default-mode, salience-motor, and visual networks. The objective of this study was to understand whether FTs of the DN are implicated in adolescent anxiety disorders. Forty-one adolescents (mean age 15.19 ± 0.82, 26 females) with one or more anxiety disorders and 55 age- and gender-matched healthy controls completed resting-state fMRI scans and a self-report survey on anxiety symptoms. Seed-to-voxel functional connectivity analyses were performed using the FTs from DN parcellation. Brain connectivity metrics were then correlated with State-Trait Anxiety Inventory (STAI) measures within each group. Adolescents with an anxiety disorder showed significant hyperconnectivity between salience-motor DN FT and cerebral cortical salience-motor regions compared to controls. Salience-motor FT connectivity with cerebral cortical sensorimotor regions was significantly correlated with STAI-trait scores in HC (R² = 0.41). Here, we report DN functional connectivity differences in adolescents diagnosed with anxiety, as well as in HC with variable degrees of anxiety traits. These observations highlight the relevance of DN as a potential clinical and sub-clinical marker of anxiety.

INTRODUCTION/BACKGROUND:According to evidence-based clinical practice guidelines, patients presenting with disabling stroke symptoms should be treated with intravenous tissue plasminogen activator (IV tPA) within 4.5 hours of time last known well. However, 25% of strokes are detected upon awakening ('wake-up strokes'; WUS) which renders patients ineligible for IV tPA administered via time-based treatment algorithms because it is impossible to establish a reliable time of symptom onset. We performed a systematic review and meta-analysis of the efficacy and safety of IV tPA compared with normal saline, placebo, or no treatment in patients with WUS using imaging-based treatment algorithms. METHODS:We searched Medline, Web of Science, and Scopus between January 1, 2006 and April 30, 2020. We included controlled trials (randomized or nonrandomized), observational cohort studies (prospective or retrospective), and single-arm studies in which adults with WUS were administered IV tPA after MR- or CT-based imaging. Our primary outcome was recovery at 90 days (defined as a modified Rankin Scale [mRS] score of 0-2) and our secondary outcomes were symptomatic intracranial hemorrhage (sICH) within 36 hours, mortality, and other adverse effects. RESULTS:We included 16 studies that enrolled a total of 14,017 patients. Most studies were conducted in Europe (37.5%) or North America (37.5%), and 1,757 patients (12.5%) received IV tPA. All studies used MRI-based (5 studies) or CT-based (10 studies) imaging selection and one study used a combination of modalities. Sixty-one percent of patients receiving IV tPA achieved mRS of 0-2 at 90 days (95% CI 51% to 70%; 12 studies), with a relative risk (RR) of 1.21 compared with patients not receiving IV tPA (95% CI 1.01 to 1.46; 4 studies). Three percent of patients receiving IV tPA experienced sICH within 36 hours (95% CI 2.5% to 4.1%; 16 studies), an RR of 4.00 compared with patients not receiving IV tPA (95% CI 2.85 to 5.61; 7 studies). CONCLUSIONS:This systematic review and meta-analysis suggests that IV tPA is associated with a better functional outcome at 90 days despite the increased but acceptable risk of sICH. Based on these results, IV tPA should be offered as a treatment for WUS patients with favorable neuroimaging findings.

Migraine is a prevalent primary headache disorder and is usually considered as benign. However, structural and functional changes in the brain of individuals with migraine have been reported. High frequency of white matter abnormalities, silent infarct-like lesions, and volumetric changes in both gray and white matter in individuals with migraine compared to controls have been demonstrated. Functional magnetic resonance imaging (MRI) studies found altered connectivity in both the interictal and ictal phase of migraine. MR spectroscopy and positron emission tomography studies suggest abnormal energy metabolism and mitochondrial dysfunction, as well as other metabolic changes in individuals with migraine. In this review, we provide a brief overview of neuroimaging studies that have helped us to characterize some of these changes and discuss their limitations, including small sample sizes and poorly defined control groups. A better understanding of alterations in the brains of patients with migraine could help not only in the diagnosis but may potentially lead to the optimization of a targeted anti-migraine therapy.

Background and aims: The Work Productivity and Activity Impairment (WPAI) questionnaire is a patientreported outcome assessing percentage of work time missed, impairment while working, overall work impairment and activity impairment over seven days prior. We report 2-year changes in WPAI, and associations with the 29-item Multiple Sclerosis Impact Scale (MSIS-29) and SymptoMScreen (self-reported symptom burden) among patients with relapsing-remitting MS (RRMS) in the Phase IIIb CASTING trial (NCT02861014). Method(s): Patients (n=680; Expanded Disability Status Scale score <=4.0) with a suboptimal response to one or two prior disease-modifying therapies (DMTs) received intravenous ocrelizumab 600mg every 24 weeks for 96 weeks. WPAI, MSIS-29 and SymptoMScreen were completed at baseline, Week 24, Year 1 and Year 2. Spearman correlations were assessed between change in WPAI subscores from baseline to Year 2, MSIS-29 subscores, and SymptoMScreen total score. Result(s): WPAI improved from baseline to Year 2, with significant reduction in overall work impairment (-3.08, p=0.020) and activity impairment (-5.69, p<0.001), and consistent trends in work time missed (-2.54, p=0.102) and impairment while working (-1.66, p=0.129). Improvement in SymptoMScreen score correlated with reduction in all WPAI measures: work time missed (rs=0.196), impairment while working (rs=0.387), overall work impairment (rs=0.362) and activity impairment (rs=0.421) over two years (all p<0.01). MSIS-29 improvements correlated with WPAI improvements over two years (Table 1). Table 1 Conclusion(s): Patients with a suboptimal response to one or two prior DMTs who switched to ocrelizumab showed improvement in work productivity (WPAI), which correlated with improvement in physical/psychological impacts of MS (MSIS-29) and decrease in symptom burden (SymptoMScreen) over two years

OBJECTIVE:To examine social, economic, and migratory influences on the health of racial and ethnic minority groups in Canada, with a special focus on Caribbean immigrants. METHODS:Combined annual cycles (2011-2016) of the Canadian Community Health Survey (CCHS) data totaling over 300,000 adult Canadian residents were aggregated. Descriptive statistics and multivariable logistic regression models were used to examine the prevalence and associated factors of (1) cardiovascular disease diagnosed by a healthcare professional, and (2) self-rated general health among racial and ethnic groups. RESULTS:Caribbeans in general, Black and other non-White Canadians had significantly higher odds (adjusted for age/sex) of reporting any cardiovascular disease compared with White Canadians. Only non-Caribbean Blacks had higher odds of self-rated fair or poor general health compared with White Canadians. Multivariate logistic regression models revealed that after controlling for social and demographic factors, immigration status and years since migration, Caribbean non-Blacks and Black Caribbeans were at higher odds of having a doctor-reported cardiovascular health condition compared with White Canadians. Caribbean non-Blacks also had higher odds of fair or poor self-rated health than White Canadians. CONCLUSION:The results of this study highlight the need for additional investigations of other potential influences on physical health statuses, especially among migrants and those of African ancestry who might be more prone to adverse health outcomes.

BACKGROUND AND PURPOSE/OBJECTIVE:Indirect consequences of the Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) pandemic include those related to failure of patients to seek or receive timely medical attention for seemingly unrelated disease. We report our experience with stroke code imaging during the early pandemic months of 2020. MATERIALS AND METHODS/METHODS:Retrospective review of stroke codes during the 2020 pandemic and both 2020 and matched 2019 prepandemic months was performed. Patient variables were age, sex, hospital location, and severity of symptoms based on the NIHSS. We reviewed the results of CT of the head, CTA, CTP, and MR imaging examinations and classified a case as imaging-positive if any of the imaging studies yielded a result that related to the clinical indication for the study. Both year-to-year and sequential comparisons were performed between pandemic and prepandemic months. RESULTS:= .03). CONCLUSIONS:During our pandemic period, there was a significantly decreased number of stroke codes but simultaneous increases in positivity rates, symptom severity, and inpatient codes. We postulate that this finding reflects the documented reluctance of patients to seek medical care during the pandemic, with the shift toward a greater proportion of inpatient stroke codes potentially reflecting the neurologic complications of the virus itself.

Slowed information processing speed is among the earliest markers of cognitive impairment in multiple sclerosis (MS) and has been associated with white matter (WM) structural integrity. Localization of WM tracts associated with slowing, but not significant impairment, on specific cognitive tasks in pediatric and young age onset MS can facilitate early and effective therapeutic intervention. Diffusion tensor imaging data were collected on 25 MS patients and 24 controls who also underwent the Symbol Digit Modalities Test (SDMT) and the computer-based Cogstate simple and choice reaction time tests. Fractional anisotropy (FA), mean (MD), radial (RD) and axial (AD) diffusivities were correlated voxel-wise with processing speed measures. All DTI metrics of several white matter tracts were significantly different between groups (p < 0.05). Notably, higher MD, RD, and AD, but not FA, in the corpus callosum correlated with lower scores on both SDMT and simple reaction time. Additionally, all diffusivity metrics in the left corticospinal tract correlated negatively with SDMT scores, whereas only MD in the right superior fronto-occipital fasciculus correlated with simple reaction time. In conclusion, subtle slowing of processing speed is correlated with WM damage in the visual-motor processing pathways in patients with young age of MS onset.

Background and aims: Natalizumab extended interval dosing (EID) is associated with lower progressive multifocal leukoencephalopathy risk than standard interval dosing (SID) in anti-JC virus antibody positive multiple sclerosis patients. However, EID efficacy has yet to be demonstrated in a randomised controlled trial, and real-world efficacy data would be valuable. Method(s): This study compared Multiple Sclerosis Performance Test (MSPT) functional changes occurring during treatment with natalizumab EID versus SID in MS PATHS, a network of healthcare institutions providing access to real-world clinical data. An MSPT segment was defined as the time between two MSPT assessments six months apart. MSPT segments with average infusion cycles >35 days and 35 days were defined as EID and SID, respectively. Patients could contribute multiple segments to both groups. Missing covariate data were multiply imputed. Covariates at segment start (Table) were balanced between groups by inverse probability weighting (IPW) based on a logistic propensity score model. Differences in annualized change in MSPT scores were compared between EID/SID arms with weighted linear regression. Result(s): Data from 152 EID and 1,079 SID segments were analysed. After IPW, all baseline factors exhibited a standard mean difference 0.05. Annualised change in MSPT scores of processing speed, manual dexterity, and ambulation did not differ significantly between EID and SID. On average, MSPT scores were maintained or improved while on natalizumab (Figure). Conclusion(s): Functional outcomes between patients treated with natalizumab EID versus SID were comparable. Cognitive processing speed, manual dexterity, and walking speed were maintained or improved over time for both treatment groups