White matter paramagnetic rim and non-rim lesions share a periventricular gradient in multiple sclerosis: A 7-T imaging study

BACKGROUND

Paramagnetic rim white matter (WM) lesions (PRL) are thought to be a main driver of non-relapsing multiple sclerosis (MS) progression. It is unknown whether cerebrospinal fluid (CSF)-soluble factors diffusing from the ventricles contribute to PRL formation.

OBJECTIVE

To investigate the distribution of PRL and non-rim brain WM lesions as a function of distance from ventricular CSF, their relationship with cortical lesions, the contribution of lesion phenotype, and localization to neurological disability.

METHODS

Lesion count and volume of PRL, non-rim WM, leukocortical lesion (LCL), and subpial/intracortical lesions were obtained at 7-T. The brain WM was divided into 1-mm-thick concentric rings radiating from the ventricles to extract PRL and non-rim WM lesion volume from each ring.

RESULTS

In total, 61 MS patients with ⩾1 PRL were included in the study. Both PRL and non-rim WM lesion volumes were the highest in the periventricular WM and declined with increasing distance from ventricles. A CSF distance-independent association was found between non-rim WM lesions, PRL, and LCL, but not subpial/intracortical lesions. Periventricular non-rim WM lesion volume was the strongest predictor of neurological disability.

CONCLUSIONS

Non-rim and PRL share a gradient of distribution from the ventricles toward the cortex, suggesting that CSF proximity equally impacts the prevalence of both lesion phenotypes.

Clinical course of multiple sclerosis with comorbid endometriosis: A matched cohort study

BACKGROUND

Endometriosis (EMS) is pain syndrome in which endometrial tissue grows outside the uterus. EMS is associated with an increased risk of multiple sclerosis (MS), a demyelinating disease of the central nervous system.

OBJECTIVE

To characterize clinical phenotypes of a cohort of patients with both EMS and MS compared to a cohort of matched controls with only MS.

METHODS

We retrospectively identified patients with EMS and MS at Beth Israel Deaconess Medical Center (BIDMC). We collected data on EMS treatments and analyzed differences in histories of gynecological cancer, smoking, fatigue, anxiety, depression, headache, and neuropathic pain compared to matched controls. We used Wilcoxon signed rank tests for paired samples to compare Expanded Disability Status Scores (EDSS) and timed 25-foot walk values (T25FW).

RESULTS

Using a case-control methodology, we found significantly increased EDSS (p < 0.001) and T25FW (p = 0.01) in the EMS-MS group compared to the MS group. More patients in the EMS-MS group had histories of smoking, anxiety, depression, and headaches, while more patients in the MS group had histories of fatigue and neuropathic pain.

CONCLUSION

When controlling for age, race, and MS therapy, those with EMS-MS experience more MS disability than controls, suggesting this population requires more monitoring and efficacious treatment.

Characterization of cortico-meningeal translocator protein expression in multiple sclerosis

Compartmentalized meningeal inflammation is thought to represent one of the key players in the pathogenesis of cortical demyelination in multiple sclerosis. Positron emission tomography targeting the 18 kDa mitochondrial Translocator Protein (TSPO) is a molecular-specific approach to quantify immune cell-mediated density in the cortico-meningeal tissue compartment in vivo. The aim of this study was to characterize cortical and meningeal TSPO expression in a heterogeneous cohort of multiple sclerosis cases using in vivo simultaneous MR-PET with 11C-PBR28, a second-generation TSPO radioligand, and ex vivo immunohistochemistry. Forty-nine multiple sclerosis patients (21 with secondary progressive and 28 with relapsing-remitting multiple sclerosis) with mixed or high affinity binding for 11C-PBR28 underwent 90-min 11C-PBR28 simultaneous MR-PET. Tracer binding was measured using 60-90 min normalized standardized uptake value ratio values sampled at mid-cortical depth and ∼3 mm above the pial surface. Data in multiple sclerosis patients were compared to 21 age-matched healthy controls. To characterize the nature of 11C-PBR28 PET uptake, the meningeal and cortical lesion cellular expression of TSPO was further described in post-mortem brain tissue from 20 cases with secondary progressive multiple sclerosis and five age-matched healthy donors. Relative to healthy controls, patients with multiple sclerosis exhibited abnormally increased TSPO signal in the cortex and meningeal tissue, diffusively in progressive disease and more localized in relapsing-remitting multiple sclerosis. In multiple sclerosis, increased meningeal TSPO levels were associated with increased Expanded Disability Status Scale scores (p = 0.007, by linear regression). Immunohistochemistry, validated using in-situ sequencing analysis, revealed increased TSPO expression in the meninges and adjacent subpial cortical lesions of post-mortem secondary progressive multiple sclerosis cases relative to control tissue. In these cases, increased TSPO expression was related to meningeal inflammation. Translocator Protein immunostaining was detected on meningeal major histocompatibility complex (MHC)-class II + macrophages and cortical activated MHC-class II + transmembrane protein (TMEM)119+ microglia. In vivo arterial blood data and neuropathology showed that endothelial binding did not significantly account for increased TSPO cortico-meningeal expression in multiple sclerosis. Our findings support the use of TSPO-PET in multiple sclerosis for imaging in vivo inflammation in the cortico-meningeal brain tissue compartment and provide in vivo evidence implicating meningeal inflammation in the pathogenesis of the disease.

Bariatric surgery outcomes in multiple sclerosis: Interplay with vitamin D and chronic pain syndromes

BACKGROUND

Obesity and lower vitamin D levels are associated with adverse outcomes in multiple sclerosis (MS). Bariatric surgery is a safe intervention in patients with MS, although it lowers vitamin D levels in the general population.

OBJECTIVE

To investigate the effects of bariatric surgery on vitamin D levels and interrogate risk factors for unsuccessful post-operative weight loss in patients with MS.

METHODS

We retrospectively identified patients with MS who underwent bariatric surgery from 2001 to 2023. Wilcoxon signed rank tests for paired samples were used to compare pre- and post-operative body mass index (BMI), expanded disability status scale (EDSS), timed 25-foot walk (T25FW), and median vitamin D values.

RESULTS

Following bariatric surgery, patients with MS had a decrease in BMI (mean percent total weight loss of 18.4 %, range 0-38 %, p < 0.001) and an increase in vitamin D values (mean increase of 23 ng/mL, range -4-32 ng/mL, p < 0.001), while no change in EDSS or T25FW was seen. Four out of 20 patients did not lose more than 5 % of their pre-operative BMI, all of whom had chronic pain syndromes and were on gabapentin.

CONCLUSION

Healthy vitamin D levels are attainable following bariatric surgery in patients with MS.

High CD4+:CD8+ ratios with herpes zoster infections in patients with multiple sclerosis on dimethyl fumarate

BACKGROUND

Dimethyl fumarate (DMF) depletes CD8+ and CD4+ T cells, and cases of herpes zoster (HZ) in patients with multiple sclerosis (MS) on DMF have been documented.

OBJECTIVES

To evaluate lymphocyte subsets in patients with MS who developed HZ on DMF (Tecfidera) compared to matched controls who did not develop HZ.

METHODS

We used linear mixed-effects models to test for differences in white blood cell count, lymphocyte percentage, absolute lymphocyte count, CD3+ percentage, absolute CD3+ count, CD4+ percentage, absolute CD4+ count, CD8+ percentage, absolute CD8+ count, and CD4+:CD8+ ratio over time in HZ and non-HZ groups.

RESULTS

Eighteen patients developed HZ while on DMF. The linear mixed-effects model for CD4+:CD8+ ratio showed a significant difference between the HZ and non-HZ groups (p = 0.033). CD4+:CD8+ ratio decreased over time in the HZ group and increased over time in the non-HZ group.

CONCLUSION

Patients with MS who develop HZ while on DMF have high CD4+:CD8+ ratios, suggesting an imbalance of CD4+ and CD8+ cells that may put a patient at risk for developing HZ while on DMF. This result emphasizes the need for lymphocyte subset monitoring (including CD4+:CD8+ ratios) on DMF, as well as vaccination prior to DMF initiation.

Blunted Post-COVID-19 Humoral Immunity in Patients With CNS Demyelinating Disorders on Anti-CD20 Treatments

With unclear characteristics of post-infection and post-vaccination immunity, the multiple sclerosis community lacks evidence to guide patients on their continued coronavirus disease 2019 (COVID-19) infection risk. As disease modifying treatments all modulate the immune system, we expect their use to alter acquired immunity to COVID-19, but the specific impact of individual treatments is unclear. To address this, we analyzed the patient and COVID-19 specific characteristics associated with post-infection humoral immunity in 58 patients with central nervous system (CNS) demyelinating disorders in the Boston metropolitan area. Univariate analysis of variance was performed using Mann Whitney U test for continuous variables, and Chi Square or Fisher Exact test for nominal variables. Univariate and stepwise multivariate nominal logistic regression identified clinical characteristics associated with COVID-19 specific nucleocapsid IgG antibody formation post-infection. Our cohort demonstrated a 42% post-infection seropositive rate with a significantly higher rate observed with shorter duration between infection and antibody collection and use of natalizumab over no/other treatment. Use of anti-CD20 treatments compared to no/other treatment was associated with a significantly lower rate of seropositivity. However, only shorter duration between infection and antibody collection as well as use of no/other treatment compared to anti-CD20 treatment were found to be independently associated with increased likelihood of post-infection seropositivity. Additionally, we demonstrate durability of antibody response up to 9 months in a small subset of patients. Thus, our data supports that patients with CNS demyelinating disorders regardless of DMT are able to form a measurable antibody response after COVID-19 infection, and that patients on anti-CD20 treatments form less robust immunity after COVID-19 infection.

Cortical and phase rim lesions on 7 T MRI as markers of multiple sclerosis disease progression

In multiple sclerosis, individual lesion-type patterns on magnetic resonance imaging might be valuable for predicting clinical outcome and monitoring treatment effects. Neuropathological and imaging studies consistently show that cortical lesions contribute to disease progression. The presence of chronic active white matter lesions harbouring a paramagnetic rim on susceptibility-weighted magnetic resonance imaging has also been associated with an aggressive form of multiple sclerosis. It is, however, still uncertain how these two types of lesions relate to each other, or which one plays a greater role in disability progression. In this prospective, longitudinal study in 100 multiple sclerosis patients (74 relapsing-remitting, 26 secondary progressive), we used ultra-high field 7-T susceptibility imaging to characterize cortical and rim lesion presence and evolution. Clinical evaluations were obtained over a mean period of 3.2 years in 71 patients, 46 of which had a follow-up magnetic resonance imaging. At baseline, cortical and rim lesions were identified in 96% and 63% of patients, respectively. Rim lesion prevalence was similar across disease stages. Patients with rim lesions had higher cortical and overall white matter lesion load than subjects without rim lesions (P = 0.018-0.05). Altogether, cortical lesions increased by both count and volume (P = 0.004) over time, while rim lesions expanded their volume (P = 0.023) whilst lacking new rim lesions; rimless white matter lesions increased their count but decreased their volume (P = 0.016). We used a modern machine learning algorithm based on extreme gradient boosting techniques to assess the cumulative power as well as the individual importance of cortical and rim lesion types in predicting disease stage and disability progression, alongside with more traditional imaging markers. The most influential imaging features that discriminated between multiple sclerosis stages (area under the curve±standard deviation = 0.82 ± 0.08) included, as expected, the normalized white matter and thalamic volume, white matter lesion volume, but also leukocortical lesion volume. Subarachnoid cerebrospinal fluid and leukocortical lesion volumes, along with rim lesion volume were the most important predictors of Expanded Disability Status Scale progression (area under the curve±standard deviation = 0.69 ± 0.12). Taken together, these results indicate that while cortical lesions are extremely frequent in multiple sclerosis, rim lesion development occurs only in a subset of patients. Both, however, persist over time and relate to disease progression. Their combined assessment is needed to improve the ability of identifying multiple sclerosis patients at risk of progressing disease.

Quantitative 7-Tesla Imaging of Cortical Myelin Changes in Early Multiple Sclerosis

Cortical demyelination occurs early in multiple sclerosis (MS) and relates to disease outcome. The brain cortex has endogenous propensity for remyelination as proven from histopathology study. In this study, we aimed at characterizing cortical microstructural abnormalities related to myelin content by applying a novel quantitative MRI technique in early MS. A combined myelin estimation (CME) cortical map was obtained from quantitative 7-Tesla (7T) T2* and T₁ acquisitions in 25 patients with early MS and 19 healthy volunteers. Cortical lesions in MS patients were classified based on their myelin content by comparison with CME values in healthy controls as demyelinated, partially demyelinated, or non-demyelinated. At follow-up, we registered changes in cortical lesions as increased, decreased, or stable CME. Vertex-wise analysis compared cortical CME in the normal-appearing cortex in 25 MS patients vs. 19 healthy controls at baseline and investigated longitudinal changes at 1 year in 10 MS patients. Measurements from the neurite orientation dispersion and density imaging (NODDI) diffusion model were obtained to account for cortical neurite/dendrite loss at baseline and follow-up. Finally, CME maps were correlated with clinical metrics. CME was overall low in cortical lesions (p = 0.03) and several normal-appearing cortical areas (p < 0.05) in the absence of NODDI abnormalities. Individual cortical lesion analysis revealed, however, heterogeneous CME patterns from extensive to partial or absent demyelination. At follow-up, CME overall decreased in cortical lesions and non-lesioned cortex, with few areas showing an increase (p < 0.05). Cortical CME maps correlated with processing speed in several areas across the cortex. In conclusion, CME allows detection of cortical microstructural changes related to coexisting demyelination and remyelination since the early phases of MS, and shows to be more sensitive than NODDI and relates to cognitive performance.

A New England COVID-19 Registry of Patients With CNS Demyelinating Disease: A Pilot Analysis

BACKGROUND AND OBJECTIVES

We sought to define the risk of severe coronavirus disease 2019 (COVID-19) infection requiring hospitalization in patients with CNS demyelinating diseases such as MS and the factors that increase the risk for severe infection to guide decisions regarding patient care during the COVID-19 pandemic.

METHODS

A pilot cohort of 91 patients with confirmed or suspected COVID-19 infection from the Northeastern United States was analyzed to characterize patient risk factors and factors associated with an increased severity of COVID-19 infection. Univariate analysis of variance was performed using the Mann-Whitney U test or analysis of variance for continuous variables and the χ² or Fisher exact test for nominal variables. Univariate and stepwise multivariate logistic regression identified clinical characteristics or symptoms associated with hospitalization.

RESULTS

Our cohort demonstrated a 27.5% hospitalization rate and a 4.4% case fatality rate. Performance on Timed 25-Foot Walk before COVID-19 infection, age, number of comorbidities, and presenting symptoms of nausea/vomiting and neurologic symptoms (e.g., paresthesia or weakness) were independent risk factors for hospitalization, whereas headache predicted a milder course without hospitalization. An absolute lymphocyte count was lower in hospitalized patients during COVID-19 infection. Use of disease-modifying therapy did not increase the risk of hospitalization but was associated with an increased need for respiratory support.

DISCUSSION

The case fatality and hospitalization rates in our cohort were similar to those found in MS and general population COVID-19 cohorts within the region. Hospitalization was associated with increased disability, age, and comorbidities but not disease-modifying therapy use.

CLICK-MS and MASTER-2 Phase IV trial design: cladribine tablets in suboptimally controlled relapsing multiple sclerosis

Cladribine tablets 10 mg (3.5 mg/kg cumulative dose over 2 years) are approved for the treatment of relapsing forms of multiple sclerosis (MS), including relapsing-remitting MS and active secondary progressive MS. However, real-world data on cladribine tablets are limited. CLICK-MS and MASTER-2 are single arm, observational, 30-month, Phase IV studies in the US evaluating the effectiveness and safety of cladribine tablets 3.5 mg/kg in patients with relapsing-remitting MS or active secondary progressive MS who had suboptimal response to prior injectable (CLICK-MS), or infusion/oral (MASTER-2) disease-modifying therapy. The primary end point is 24-month annualized relapse rate. Key secondary end points include patient-reported outcomes on quality of life measures, treatment adherence and adverse events. Studies began in 2019 and are expected to be completed in 2023. Trial registration number • CLICK-MS: NCT03933215 (ClinicalTrials.gov) Full title; CLadribine tablets: observational evaluation of effectIveness and patient-reported outcomes in suboptimally Controlled patients previously taKing injectable disease-modifying drugs for relapsing forms of Multiple Sclerosis • MASTER-2: NCT03933202 (ClinicalTrials.gov) Full title; Cladribine tablets: observational evaluation of effectiveness and patient-reported outcomes in suboptiMAlly controlled patientS previously Taking oral or infusion disEase-modifying dRugs for relapsing forms of multiple sclerosis.

7 T imaging reveals a gradient in spinal cord lesion distribution in multiple sclerosis

We used 7 T MRI to: (i) characterize the grey and white matter pathology in the cervical spinal cord of patients with early relapsing-remitting and secondary progressive multiple sclerosis; (ii) assess the spinal cord lesion spatial distribution and the hypothesis of an outside-in pathological process possibly driven by CSF-mediated immune cytotoxic factors; and (iii) evaluate the association of spinal cord pathology with brain burden and its contribution to neurological disability. We prospectively recruited 20 relapsing-remitting, 15 secondary progressive multiple sclerosis participants and 11 age-matched healthy control subjects to undergo 7 T imaging of the cervical spinal cord and brain as well as conventional 3 T brain acquisition. Cervical spinal cord imaging at 7 T was used to segment grey and white matter, including lesions therein. Brain imaging at 7 T was used to segment cortical and white matter lesions and 3 T imaging for cortical thickness estimation. Cervical spinal cord lesions were mapped voxel-wise as a function of distance from the inner central canal CSF pool to the outer subpial surface. Similarly, brain white matter lesions were mapped voxel-wise as a function of distance from the ventricular system. Subjects with relapsing-remitting multiple sclerosis showed a greater predominance of spinal cord lesions nearer the outer subpial surface compared to secondary progressive cases. Inversely, secondary progressive participants presented with more centrally located lesions. Within the brain, there was a strong gradient of lesion formation nearest the ventricular system that was most evident in participants with secondary progressive multiple sclerosis. Lesion fractions within the spinal cord grey and white matter were related to the lesion fraction in cerebral white matter. Cortical thinning was the primary determinant of the Expanded Disability Status Scale, white matter lesion fractions in the spinal cord and brain of the 9-Hole Peg Test and cortical thickness and spinal cord grey matter cross-sectional area of the Timed 25-Foot Walk. Spinal cord lesions were localized nearest the subpial surfaces for those with relapsing-remitting and the central canal CSF surface in progressive disease, possibly implying CSF-mediated pathogenic mechanisms in lesion development that may differ between multiple sclerosis subtypes. These findings show that spinal cord lesions involve both grey and white matter from the early multiple sclerosis stages and occur mostly independent from brain pathology. Despite the prevalence of cervical spinal cord lesions and atrophy, brain pathology seems more strongly related to physical disability as measured by the Expanded Disability Status Scale.

The relevance of multiple sclerosis cortical lesions on cortical thinning and their clinical impact as assessed by 7.0-T MRI

OBJECTIVE

This study aimed to investigate at 7.0-T MRI a) the role of multiple sclerosis (MS) cortical lesions in cortical tissue loss b) their relation to neurological disability.

METHODS

In 76 relapsing remitting and 26 secondary progressive MS patients (N = 102) and 56 healthy subjects 7.0-T T₂^*-weighted images were acquired for lesion segmentation; 3.0-T T₁-weighted structural scans for cortical surface reconstruction/cortical thickness estimation. Patients were dichotomized based on the median cortical lesion volume in low and high cortical lesion load groups that differed by age, MS phenotype and degree of neurological disability. Group differences in cortical thickness were tested on reconstructed cortical surface. Patients were evaluated clinically by means of the Expanded Disability Status Scale (EDSS).

RESULTS

Cortical lesions were detected in 96% of patients. White matter lesion load was greater in the high than in the low cortical lesion load MS group (p = 0.01). Both MS groups disclosed clusters (prevalently parietal) of cortical thinning relative to healthy subjects, though these regions did not show the highest cortical lesion density, which predominantly involved frontal regions. Cortical thickness decreased on average by 0.37 mm, (p = 0.002) in MS patients for each unit standard deviation change in white matter lesion volume. The odds of having a higher EDSS were associated with cortical lesion volume (1.78, p = 0.01) and disease duration (1.15, p < 0.001).

CONCLUSION

Cortical thinning in MS is not directly related to cortical lesion load but rather with white matter lesion volume. Neurological disability in MS is better explained by cortical lesion volume assessment.

Brainstem lesions are associated with sleep apnea in multiple sclerosis

Background

Studies linking MRI findings in MS patients with obstructive sleep apnea severity are limited.

Objective

We conducted a retrospective study to assess MRI abnormalities associated with obstructive sleep apnea (OSA) in patients with multiple sclerosis (MS).

Methods

We performed retrospective chart review of 65 patients with multiple sclerosis who had undergone polysomnography (PSG) for fatigue as well as brain MRI. We measured the number of lesions in the brainstem and calculated the standardized third ventricular width (sTVW) as a measure of brain atrophy, and subsequently performed correlation analyses of the apnea-hypopnea index (AHI) with brainstem lesion location, sTVW, and Expanded Disability Status Scale (EDSS).

Results

MS Patients with OSA were significantly older and had a higher body mass index (BMI) and higher AHI measures than patients without OSA. After adjustment for covariates, significant associations were found between AHI and lesion burden in the midbrain (p < 0.01) and pons (p = 0.05), but not medulla.

Conclusions

Midbrain and pontine lesions burden correlated with AHI, suggesting MS lesion location could contribute to development of OSA.

Profiles of cortical inflammation in multiple sclerosis by 11C-PBR28 MR-PET and 7 Tesla imaging

BACKGROUND

Neuroinflammation with microglia activation is thought to be closely related to cortical multiple sclerosis (MS) lesion pathogenesis.

OBJECTIVE

Using 11C-PBR28 and 7 Tesla (7T) imaging, we assessed in 9 relapsing-remitting multiple sclerosis (RRMS) and 10 secondary progressive multiple sclerosis (SPMS) patients the following: (1) microglia activation in lesioned and normal-appearing cortex, (2) cortical lesion inflammatory profiles, and (3) the relationship between neuroinflammation and cortical integrity.

METHODS

Mean 11C-PBR28 uptake was measured in focal cortical lesions, cortical areas with 7T quantitative T2* (q-T2*) abnormalities, and normal-appearing cortex. The relative difference in cortical 11C-PBR28 uptake between patients and 14 controls was used to classify cortical lesions as either active or inactive. Disease burden was investigated according to cortical lesion inflammatory profiles. The relation between q-T2* and 11C-PBR28 uptake along the cortex was assessed.

RESULTS

11C-PBR28 uptake was abnormally high in cortical lesions in RRMS and SPMS; in SPMS, tracer uptake was significantly increased also in normal-appearing cortex. 11C-PBR28 uptake and q-T2* correlated positively in many cortical areas, negatively in some regions. Patients with high cortical lesion inflammation had worse clinical outcome and higher intracortical lesion burden than patients with low inflammation.

CONCLUSION

11C-PBR28 and 7T imaging reveal distinct profiles of cortical inflammation in MS, which are related to disease burden.

Leptomeningeal Enhancement on 3D-FLAIR MRI in Multiple Sclerosis: Systematic Observations in Clinical Practice

BACKGROUND AND PURPOSE

Meningeal inflammation is implicated in cortical demyelination and disability progression in multiple sclerosis (MS). Gadolinium (Gd)-enhanced 3-dimensional (3D) FLAIR (fluid-attenuated inversion recovery) magnetic resonance imaging (MRI) can identify leptomeningeal enhancement (LME) in MS. Further characterization is needed to determine if LME is an imaging biomarker for meningeal inflammation. We sought to characterize the natural history of LME in the community setting, including persistence/resolution, effect of disease-modifying therapy, scanner variability, timing of acquisition, and imaging pitfalls that may lead to misinterpretation.

METHODS

A total of 341 MRI exams with Gd-enhanced 3D-FLAIR were reviewed in MS and non-MS patients to determine frequency of enhancement by MS subtype and association with therapy. A phantom was used to assess scanner variability. Two MS patients with seven LME were imaged at four postinjection time points to generate time-intensity curves. Imaging pitfalls were compiled.

RESULTS

A total of 16.6% (40/241) of MS patients revealed LME compared to 8% (8/100) in non-MS patients (P = .04). There was no association with MS subtype, therapy, or disease activity. Detection using General Electric's version of 3D-FLAIR (29%) was greater than with Siemen's 3D-FLAIR (12%) at 1.5T (Tesla) (P < .001). Lesions were generally stable but resolved in 2 patients following high-dose steroids. LME kinetics were heterogeneous, even within patients, without uniform optimal time for acquisition. Enhancement curves exhibited three different variations, similar to the two-compartment model. Imaging pitfalls included enhancements of uncertain biologic significance, cortical veins and anatomic structures, and imaging artifacts.

CONCLUSIONS

Awareness of LME characteristics, variability with imaging parameters, and imaging pitfalls will facilitate determining the potential role as an imaging biomarker for meningeal inflammation.

Characterization of thalamic lesions and their correlates in multiple sclerosis by ultra-high-field MRI

BACKGROUND

Thalamic pathology is a marker for neurodegeneration and multiple sclerosis (MS) disease progression.

OBJECTIVE

To characterize (1) the morphology of thalamic lesions, (2) their relation to cortical and white matter (WM) lesions, and (3) clinical measures, and to assess (4) the imaging correlates of thalamic atrophy.

METHODS

A total of 90 MS patients and 44 healthy controls underwent acquisition of 7 Tesla images for lesion segmentation and 3 Tesla scans for atrophy evaluation. Thalamic lesions were classified according to the shape and the presence of a central venule. Regression analysis identified the predictors of (1) thalamic atrophy, (2) neurological disability, and (3) information processing speed.

RESULTS

Thalamic lesions were mostly ovoid than periventricular, and for the great majority (78%) displayed a central venule. Lesion volume in the thalamus, cortex, and WM did not correlate with each other. Thalamic atrophy was only associated with WM lesion volume (p = 0.002); subpial and WM lesion volumes were associated with neurological disability (p = 0.016; p < 0.001); and WM and thalamic lesion volumes were related with cognitive impairment (p < 0.001; p = 0.03).

CONCLUSION

Thalamic lesions are unrelated to those in the cortex and WM, suggesting that they may not share common pathogenic mechanisms and do not contribute to thalamic atrophy. Combined WM, subpial, and thalamic lesion volumes at 7 Tesla contribute to the disease severity.

COVID-19 in teriflunomide-treated patients with multiple sclerosis

The outbreak of a severe acute respiratory syndrome caused by a novel coronavirus (COVID-19), has raised health concerns for patients with multiple sclerosis (MS) who are commonly on long-term immunotherapies. Managing MS during the pandemic remains challenging with little published experience and no evidence-based guidelines. We present five teriflunomide-treated patients with MS who subsequently developed active COVID-19 infection. The patients continued teriflunomide therapy and had self-limiting infection, without relapse of their MS. These observations have implications for the management of MS in the setting of the COVID-19 pandemic.

Prevalence of Latent Tuberculosis in the Multiple Sclerosis Clinic and Effect of Multiple Sclerosis Treatment on Tuberculosis Testing

Background

Patients with a compromised immune system are at risk for converting from latent tuberculosis infection (LTBI) to active tuberculosis (TB) infection. Multiple sclerosis (MS) therapies may put individuals with LTBI at higher risk of TB.

Methods

Patients at the Beth Israel Deaconess Medical Center MS Clinic were screened for TB as part of routine testing with the QuantiFERON-TB Gold In-Tube (QFT-GIT) assay (Cellestis Ltd) from 2013 to 2017. Patients were tested either before or during immunomodulatory therapy.

Results

Four of 222 patients (1.8%; 95% CI, 0.1%-3.6%) had positive QFT-GIT results; three patients had risk factors for TB, having emigrated from TB-endemic countries or worked in the health care industry. Twenty-eight of 222 patients (12.6%) had an indeterminate assay result, and 75.0% of these occurred in patients taking dimethyl fumarate. Fingolimod, natalizumab, or anti-CD20 treatments showed 0% to 7.7% indeterminate results.

Conclusions

The prevalence of LTBI was 1.8% in the Beth Israel Deaconess Medical Center MS Clinic. Not all LTBI cases were associated with known risk factors for TB. Screening for LTBI before starting immunosuppressive agents for MS could help prevent activation of TB. Dimethyl fumarate use is associated with indeterminate QFT-GIT results, possibly due to functional effects on lymphocytes and levels of cytokines, such as interferon gamma. In contrast, fingolimod use was rarely associated with indeterminate QFT-GIT results despite a high rate of lymphopenia in virtually all patients.

Correction to: Risk factors for lymphopenia in patients with relapsing-remitting multiple sclerosis treated with dimethyl fumarate

Unfortunately, the given name and family name of first author was incorrectly tagged in the xml data, therefore it is abbreviated wrongly as "Morales FS" in Pubmed. The correct given name is Fabian and family name is Sierra Morales. Auhtor name should be abbreviated as Sierra Morales F.

Risk factors for lymphopenia in patients with relapsing-remitting multiple sclerosis treated with dimethyl fumarate

OBJECTIVES

To identify risk factors for DMF-induced lymphopenia and characterize its impact on T lymphocyte subsets in MS patients.

METHODS

We performed a retrospective analysis of 194 RRMS patients treated with DMF at the Beth Israel Deaconess Medical Center (BIDMC) over a median of 17 months. We reviewed demographics, ethnic background, prior medication history, complete blood counts and T lymphocyte subsets. Possible lymphopenia risk factors examined included age, prior natalizumab exposure, vitamin D levels, and concomitant exposure to carbamazepine, opiates, tobacco, or steroids. Lymphopenia was defined as grade 1: absolute lymphocytes count (ALC) 800-999/μl; grade 2: ALC 500-799/μl; grade 3: ALC 200-499/μl; and grade 4: ALC < 200/μl.

RESULTS

Of 194 DMF-treated patients, 73 (38%) developed lymphopenia and reached an ALC nadir after a median of 504 days (range 82-932). Risk of developing DMF-induced lymphopenia increased with BMI 25-30, older age, white ethnicity, non-smoking status, and lowest quartile baseline ALC. Prior exposure to natalizumab or concomitant steroid, opiates or carbamazepine/oxcarbamazepine use was not associated with lymphopenia. Compared to baseline levels, CD8 T cells were significantly more reduced than CD4 cells. CD8 counts were more commonly reduced with age or white ethnicity. Subjects with BMI 25-30 was associated with a higher risk of abnormal CD4 cell count reductions. In contrast, non-smokers were more likely to experience reductions in both CD4 and CD8 counts while on DMF.

CONCLUSIONS

Patients with low baseline lymphocyte counts, with intermediate BMI, with white ethnicity, with advanced age, or with no tobacco use, had a significantly higher incidence of lymphopenia on DMF. Intermediate BMI or lowest quartile baseline ALC predicted low CD4 levels, while advanced age or white ethnicity predicted low CD8 levels from DMF exposure.

Risk factors for lymphopenia in patients with relapsing-remitting multiple sclerosis treated with dimethyl fumarate

OBJECTIVES

To identify risk factors for DMF-induced lymphopenia and characterize its impact on T lymphocyte subsets in MS patients.

METHODS

We performed a retrospective analysis of 194 RRMS patients treated with DMF at the Beth Israel Deaconess Medical Center (BIDMC) over a median of 17 months. We reviewed demographics, ethnic background, prior medication history, complete blood counts and T lymphocyte subsets. Possible lymphopenia risk factors examined included age, prior natalizumab exposure, vitamin D levels, and concomitant exposure to carbamazepine, opiates, tobacco, or steroids. Lymphopenia was defined as grade 1: absolute lymphocytes count (ALC) 800-999/μl; grade 2: ALC 500-799/μl; grade 3: ALC 200-499/μl; and grade 4: ALC < 200/μl.

RESULTS

Of 194 DMF-treated patients, 73 (38%) developed lymphopenia and reached an ALC nadir after a median of 504 days (range 82-932). Risk of developing DMF-induced lymphopenia increased with BMI 25-30, older age, white ethnicity, non-smoking status, and lowest quartile baseline ALC. Prior exposure to natalizumab or concomitant steroid, opiates or carbamazepine/oxcarbamazepine use was not associated with lymphopenia. Compared to baseline levels, CD8 T cells were significantly more reduced than CD4 cells. CD8 counts were more commonly reduced with age or white ethnicity. Subjects with BMI 25-30 was associated with a higher risk of abnormal CD4 cell count reductions. In contrast, non-smokers were more likely to experience reductions in both CD4 and CD8 counts while on DMF.

CONCLUSIONS

Patients with low baseline lymphocyte counts, with intermediate BMI, with white ethnicity, with advanced age, or with no tobacco use, had a significantly higher incidence of lymphopenia on DMF. Intermediate BMI or lowest quartile baseline ALC predicted low CD4 levels, while advanced age or white ethnicity predicted low CD8 levels from DMF exposure.

Longitudinal Characterization of Cortical Lesion Development and Evolution in Multiple Sclerosis with 7.0-T MRI

Background Cortical lesions develop early in multiple sclerosis (MS) and play a major role in disease progression. MRI at 7.0 T shows high sensitivity for detection of cortical lesions as well as better spatial resolution and signal-to-noise ratio compared with lower field strengths. Purpose To longitudinally characterize (a) the development and evolution of cortical lesions in multiple sclerosis across the cortical width, sulci, and gyri; (b) their relation with white matter lesion accrual; and (c) the contribution of 7.0-T cortical and white matter lesion load and cortical thickness to neurologic disability. Materials and Methods Twenty participants with relapsing-remitting MS and 13 with secondary progressive MS, along with 10 age-matched healthy controls, were prospectively recruited from 2010 to 2016 to acquire, in two imaging sessions (mean interval, 1.5 years), 7.0-T MRI T2*-weighted gradient-echo images (0.33 × 0.33 × 1.0 mm3) for cortical and white matter lesion segmentation and 3.0-T T1-weighted images for cortical surface reconstruction and cortical thickness estimation. Cortical lesions were sampled through the cortex to quantify cortical lesion distribution. The Expanded Disability Status Scale (EDSS) was used to assess neurologic disability. Nonparametric statistics assessed differences between and within groups in MRI metrics of cortical and white matter lesion burden; regression analysis explored associations of disability with MRI metrics. Results Twenty-five of 31 (81%) participants developed new cortical lesions per year (intracortical, 1.3 ± 1.7 vs leukocortical, 0.7 ± 1.9; P = .04), surpassing white matter lesion accrual (cortical, 2.0 ± 2.8 vs white matter, 0.7 ± 0.6; P = .01). In contrast to white matter lesions, cortical lesion accrual was greater in participants with secondary progressive MS than with relapsing-remitting MS (3.6 lesions/year ± 4.2 vs 1.1 lesions/year ± 0.9, respectively; P = .03) and preferentially localized in sulci. Total cortical lesion volume independently predicted baseline EDSS (β = 1.5, P < .001) and EDSS changes at follow-up (β = 0.5, P = .003). Conclusion Cortical lesions predominantly develop intracortically and within sulci, suggesting an inflammatory cerebrospinal fluid-mediated lesion pathogenesis. Cortical lesion accumulation was prominent at 7.0 T and independently predicted neurologic disability progression. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Filippi and Rocca in this issue.

Changes in structural network are associated with cortical demyelination in early multiple sclerosis

The aim of this study was to investigate the interplay between structural connectivity and cortical demyelination in early multiple sclerosis. About 27 multiple sclerosis patients and 18 age-matched controls underwent two MRI scanning sessions. The first was done at 7T and involved acquiring quantitative T₁ and T₂ * high-resolution maps to estimate cortical myelination. The second was done on a Connectom scanner and consisted of acquiring high angular resolution diffusion-weighted images to compute white matter structural connectivity metrics: strength, clustering and local efficiency. To further investigate the interplay between structural connectivity and cortical demyelination, patients were divided into four groups according to disease-duration: 0-1 year, 1-2 years, 2-3 years, and >3 years. ANOVA and Spearman's correlations were used to highlight relations between metrics. ANOVA detected a significant effect between disease duration and both cortical myelin (p = 2 × 10^-8 ) and connectivity metrics (p < 10^-4 ). We observed significant cortical myelin loss in the shorter disease-duration cohorts (0-1 year, p = .0015), and an increase in connectivity in the longer disease-duration cohort (2-3 years, strength: p = .01, local efficiency: p = .002, clustering: p = .001). Moreover, significant covariations between myelin estimation and white matter connectivity metrics were observed: Spearman's Rho correlation coefficients of 0.52 (p = .0003), 0.55 (p = .0001), and 0.53 (p = .0001) for strength, local efficiency, and clustering, respectively. An association between cortical myelin loss and changes in white matter connectivity in early multiple sclerosis was detected. These changes in network organization might be the result of compensatory mechanisms in response to the ongoing cortical diffuse damage in the early stages of multiple sclerosis.

In vivo characterization of cortical and white matter neuroaxonal pathology in early multiple sclerosis

Neuroaxonal pathology is a main determinant of disease progression in multiple sclerosis; however, its underlying pathophysiological mechanisms, including its link to inflammatory demyelination and temporal occurrence in the disease course are still unknown. We used ultra-high field (7 T), ultra-high gradient strength diffusion and T1/T2-weighted myelin-sensitive magnetic resonance imaging to characterize microstructural changes in myelin and neuroaxonal integrity in the cortex and white matter in early stage multiple sclerosis, their distribution in lesional and normal-appearing tissue, and their correlations with neurological disability. Twenty-six early stage multiple sclerosis subjects (disease duration ≤5 years) and 24 age-matched healthy controls underwent 7 T T2*-weighted imaging for cortical lesion segmentation and 3 T T1/T2-weighted myelin-sensitive imaging and neurite orientation dispersion and density imaging for assessing microstructural myelin, axonal and dendrite integrity in lesional and normal-appearing tissue of the cortex and the white matter. Conventional mean diffusivity and fractional anisotropy metrics were also assessed for comparison. Cortical lesions were identified in 92% of early multiple sclerosis subjects and they were characterized by lower intracellular volume fraction (P = 0.015 by paired t-test), lower myelin-sensitive contrast (P = 0.030 by related-samples Wilcoxon signed-rank test) and higher mean diffusivity (P = 0.022 by related-samples Wilcoxon signed-rank test) relative to the contralateral normal-appearing cortex. Similar findings were observed in white matter lesions relative to normal-appearing white matter (all P < 0.001), accompanied by an increased orientation dispersion (P < 0.001 by paired t-test) and lower fractional anisotropy (P < 0.001 by related-samples Wilcoxon signed-rank test) suggestive of less coherent underlying fibre orientation. Additionally, the normal-appearing white matter in multiple sclerosis subjects had diffusely lower intracellular volume fractions than the white matter in controls (P = 0.029 by unpaired t-test). Cortical thickness did not differ significantly between multiple sclerosis subjects and controls. Higher orientation dispersion in the left primary motor-somatosensory cortex was associated with increased Expanded Disability Status Scale scores in surface-based general linear modelling (P < 0.05). Microstructural pathology was frequent in early multiple sclerosis, and present mainly focally in cortical lesions, whereas more diffusely in white matter. These results suggest early demyelination with loss of cells and/or cell volumes in cortical and white matter lesions, with additional axonal dispersion in white matter lesions. In the cortex, focal lesion changes might precede diffuse atrophy with cortical thinning. Findings in the normal-appearing white matter reveal early axonal pathology outside inflammatory demyelinating lesions.

PML-IRIS in an HIV-2-infected patient presenting as Bell's palsy

We present the case of an HIV-2-infected patient who developed progressive multifocal leukoencephalopathy (PML) in the setting of immune reconstitution inflammatory syndrome (IRIS) presenting as Bell's palsy. The brain MRI showed a single lesion in the facial colliculus considered initially to be ischemic in nature. This case report should alert clinicians that PML can occur in the setting of HIV-2 infection. It also illustrates the difficulty of establishing the diagnosis of PML.

Heterogeneous pathological processes account for thalamic degeneration in multiple sclerosis: Insights from 7 T imaging

BACKGROUND

Thalamic degeneration impacts multiple sclerosis (MS) prognosis.

OBJECTIVE

To investigate heterogeneous thalamic pathology, its correlation with white matter (WM), cortical lesions and thickness, and as function of distance from cerebrospinal fluid (CSF).

METHODS

In 41 MS subjects and 17 controls, using 3 and 7 T imaging, we tested for (1) differences in thalamic volume and quantitative T₂* (q-T₂*) (2) globally and (3) within concentric bands originating from the CSF/thalamus interface; (4) the relation between thalamic, cortical, and WM metrics; and (5) the contribution of magnetic resonance imaging (MRI) metrics to clinical scores. We also assessed MS thalamic lesion distribution as a function of distance from CSF.

RESULTS

Thalamic lesions were mainly located next to the ventricles. Thalamic volume was decreased in MS versus controls ( p < 10^-2); global q-T₂* was longer in secondary progressive multiple sclerosis (SPMS) only ( p < 10^-2), indicating myelin and/or iron loss. Thalamic atrophy and longer q-T₂* correlated with WM lesion volume ( p < 0.01). In relapsing-remitting MS, q-T₂* thalamic abnormalities were located next to the WM ( p < 0.01 (uncorrected), p = 0.09 (corrected)), while they were homogeneously distributed in SPMS. Cortical MRI metrics were the strongest predictors of clinical outcome.

CONCLUSION

Heterogeneous pathological processes affect the thalamus in MS. While focal lesions are likely mainly driven by CSF-mediated factors, overall thalamic degeneration develops in association with WM lesions.

Challenges in the diagnosis and treatment of CNS demyelinating disorders in Zambia

Demyelinating disease occurs in a population of black adult Zambians whose genetic and environmental risk factors for multiple sclerosis are thought to be rare. The diagnosis of demyelinating disease was based predominantly on compatible clinical history and neurologic exam findings, and in some cases, more definitely established by cerebrospinal fluid exam and imaging findings. When available, laboratory studies excluded other known causes of CNS demyelination. Timely evaluation and treatment with disease-modifying therapies was related to the patient’s employment status. Lack of financial means to go abroad was a major hurdle in a patient’s ability to receive treatment. Significant barriers often prohibit timely diagnosis and prevent proper management of these patients.

The association between intra- and juxta-cortical pathology and cognitive impairment in multiple sclerosis by quantitative T2* mapping at 7 T MRI

Using quantitative T₂* at 7 Tesla (T) magnetic resonance imaging, we investigated whether impairment in selective cognitive functions in multiple sclerosis (MS) can be explained by pathology in specific areas and/or layers of the cortex.

Thirty-one MS patients underwent neuropsychological evaluation, acquisition of 7 T multi-echo T₂* gradient-echo sequences, and 3 T anatomical images for cortical surfaces reconstruction. Seventeen age-matched healthy subjects served as controls.

Cortical T₂* maps were sampled at various depths throughout the cortex and juxtacortex. Relation between T₂*, neuropsychological scores and a cognitive index (CI), calculated from a principal component analysis on the whole battery, was tested by a general linear model.

Cognitive impairment correlated with T₂* increase, independently from white matter lesions and cortical thickness, in cortical areas highly relevant for cognition belonging to the default-mode network (p < 0.05 corrected). Dysfunction in different cognitive functions correlated with longer T₂* in selective cortical regions, most of which showed longer T₂* relative to controls. For most tests, this association was strongest in deeper cortical layers. Executive dysfunction, however, was mainly related with pathology in juxtameningeal cortex. T₂* explained up to 20% of the variance of the CI, independently of conventional imaging metrics (adjusted-R²: 52–67%, p < 5.10^− 4).

Location of pathology across the cortical width and mantle showed selective correlation with impairment in differing cognitive domains. These findings may guide studies at lower field strength designed to develop surrogate markers of cognitive impairment in MS.

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Cognitive deficit in multiple sclerosis is associated with cortical T₂* increase.

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Location of clusters of correlation varies upon affected cognitive domains.

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Global cognitive deficit was associated with T₂* increase in deepest cortical layers.

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Executive dysfunction was associated with T₂* increase in outer cortical layers.

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Regional T₂* explained up to 20% of the variance of cognitive performance in MS.

Neuroinflammatory component of gray matter pathology in multiple sclerosis

OBJECTIVE

In multiple sclerosis (MS), using simultaneous magnetic resonance-positron emission tomography (MR-PET) imaging with ¹¹ C-PBR28, we quantified expression of the 18kDa translocator protein (TSPO), a marker of activated microglia/macrophages, in cortex, cortical lesions, deep gray matter (GM), white matter (WM) lesions, and normal-appearing WM (NAWM) to investigate the in vivo pathological and clinical relevance of neuroinflammation.

METHODS

Fifteen secondary-progressive MS (SPMS) patients, 12 relapsing-remitting MS (RRMS) patients, and 14 matched healthy controls underwent ¹¹ C-PBR28 MR-PET. MS subjects underwent 7T T2*-weighted imaging for cortical lesion segmentation, and neurological and cognitive evaluation. ¹¹ C-PBR28 binding was measured using normalized 60- to 90-minute standardized uptake values and volume of distribution ratios.

RESULTS

Relative to controls, MS subjects exhibited abnormally high ¹¹ C-PBR28 binding across the brain, the greatest increases being in cortex and cortical lesions, thalamus, hippocampus, and NAWM. MS WM lesions showed relatively modest TSPO increases. With the exception of cortical lesions, where TSPO expression was similar, ¹¹ C-PBR28 uptake across the brain was greater in SPMS than in RRMS. In MS, increased ¹¹ C-PBR28 binding in cortex, deep GM, and NAWM correlated with neurological disability and impaired cognitive performance; cortical thinning correlated with increased thalamic TSPO levels.

INTERPRETATION

In MS, neuroinflammation is present in the cortex, cortical lesions, deep GM, and NAWM, is closely linked to poor clinical outcome, and is at least partly linked to neurodegeneration. Distinct inflammatory-mediated factors may underlie accumulation of cortical and WM lesions. Quantification of TSPO levels in MS could prove to be a sensitive tool for evaluating in vivo the inflammatory component of GM pathology, particularly in cortical lesions. Ann Neurol 2016;80:776-790.

WAVE1 and Regulation of Actin Nucleation in Myelination

The myelin sheath can be compared to the neuronal growth cone in that the unfurled sheath looks like a giant lamellum. The authors recently tested this hypothesis by examining the importance of WAVE1, a regulator of lamellipodia formation in neurons and other cells, in myelinogenesis. They found that WAVE1 is critical for formation of oligodendrocyte lamellae and myelin sheaths. They review the regulation of WAVE1 and how WAVE1 is transported and localized to lamellipodia. Because they found that some but not all myelination was impaired by knockout of WAVE1 function, they hypothesize that other regulators of actin nucleation help oligodendrocytes produce myelin in parallel with WAVE1 function. Interestingly, they found that oligodendrocyte maturation also is disturbed with WAVE1 knockout and propose that proper localization and transport of signaling molecules relevant to the integrin signaling cascade are disrupted by loss of WAVE1 function. NEUROSCIENTIST 13(5):486—491, 2007. DOI: 10.1177/1073858407299423

Relapse frequency in transitioning from natalizumab to dimethyl fumarate: assessment of risk factors

Risk of relapse after natalizumab (NAT) cessation and switch to dimethyl fumarate (DMF) is unknown. The objective of this paper is to identify the risk and associated risk factors for relapse after switching from NAT to DMF in relapsing-remitting multiple sclerosis. Patients (n = 30) were treated with NAT for ≥12 months and then switched to DMF in a mean of 50 days. Patient age, annualized relapse rates (ARR), Expanded Disability Status Scale scores (EDSS), and lymphocyte counts were assessed. Overall, eight patients (27 %) had relapses after switching to DMF. Five patients (17 %) suffered severe relapses with multifocal clinical and radiological findings. New lesions by MRI (T2 hyperintense or enhancing) were observed in 35 % of patients. Relapses occurred at a mean of 3.5 months after NAT cessation. Patient age and elevated ARR prior to NAT use were significantly associated with risk of relapse after switch to DMF. Once on DMF for 4 months prior to relapse, lymphocyte count decreased more significantly in patients without relapses than those with relapses. Switching from NAT to DMF correlated with increased relapses. Young patient age, high ARR and stability of lymphocyte counts were risk factors for relapse after transition from NAT to DMF.

Beyond focal cortical lesions in MS: An in vivo quantitative and spatial imaging study at 7T

OBJECTIVES

Using quantitative T2* 7-tesla (7T) MRI as a marker of demyelination and iron loss, we investigated, in patients with relapsing-remitting multiple sclerosis (RRMS) and secondary progressive multiple sclerosis (SPMS), spatial and tissue intrinsic characteristics of cortical lesion(s) (CL) types, and structural integrity of perilesional normal-appearing cortical gray matter (NACGM) as a function of distance from lesions.

METHODS

Patients with MS (18 RRMS, 11 SPMS), showing at least 2 CL, underwent 7T T2* imaging to obtain (1) magnitude images for segmenting focal intracortical lesion(s) (ICL) and leukocortical lesion(s) (LCL), and (2) cortical T2* maps. Anatomical scans were collected at 3T for cortical surface reconstruction using FreeSurfer. Seventeen age-matched healthy participants served as controls.

RESULTS

ICL were predominantly located in sulci of frontal, parietal, and cingulate cortex; LCL distribution was more random. In MS, T2* was higher in both ICL and LCL, indicating myelin and iron loss, than in NACGM (p < 0.00003) irrespective of CL subtype and MS phenotype. T2* was increased in perilesional cortex, tapering away from CL toward NACGM, the wider changes being for LCL in SPMS. NACGM T2* was higher in SPMS relative to RRMS (p = 0.006) and healthy cortex (p = 0.02).

CONCLUSIONS

CL had the same degree of demyelination and iron loss regardless of lesion subtype and disease stage. Cortical damage expanded beyond visible CL, close to lesions in RRMS, and more diffusely in SPMS. Evaluation of NACGM integrity, beyond focal CL, could represent a surrogate marker of MS progression.

Is the Relationship between Cortical and White Matter Pathologic Changes in Multiple Sclerosis Spatially Specific? A Multimodal 7-T and 3-T MR Imaging Study with Surface and Tract-based Analysis

PURPOSE

To investigate in vivo the spatial specificity of the interdependence between intracortical and white matter (WM) pathologic changes as function of cortical depth and distance from the cortex in multiple sclerosis (MS), and their independent contribution to physical and cognitive disability.

MATERIALS AND METHODS

This study was institutional review board-approved and participants gave written informed consent. In 34 MS patients and 17 age-matched control participants, 7-T quantitative T2* maps, 3-T T1-weighted anatomic images for cortical surface reconstruction, and 3-T diffusion tensor images (DTI) were obtained. Cortical quantitative T2* maps were sampled at 25%, 50%, 75% depth from pial surface. Tracts of interest were reconstructed by using probabilistic tractography. The relationship between DTI metrics voxelwise of the tracts and cortical integrity in the projection cortex was tested by using multilinear regression models.

RESULTS

In MS, DTI abnormal findings along tracts correlated with quantitative T2* changes (suggestive of iron and myelin loss) at each depth of the cortical projection area (P < .01, corrected). This association, however, was not spatially specific because abnormal findings in WM tracts also related to cortical pathologic changes outside of the projection cortex of the tract (P < .001). Expanded Disability Status Scale pyramidal score was predicted by axial diffusivity along the corticospinal tract (β = 4.6 × 10(3); P < .001), Symbol Digit Modalities Test score by radial diffusivity along the cingulum (β = -4.3 × 10(4); P < .01), and T2* in the cingulum cortical projection at 25% depth (β = -1.7; P < .05).

CONCLUSION

Intracortical and WM injury are concomitant pathologic processes in MS, which are not uniquely distributed according to a tract-cortex-specific pattern; their association may reflect a common stage-dependent mechanism.

Targeting remyelination treatment for multiple sclerosis

Since disability in multiple sclerosis (MS) is a product of neurodegeneration and deficient remyelination, the ability to enhance neuroregeneration and myelin regeneration in MS is an enticing goal for MS drug development. In particular, remyelination treatments could promote return of neurological function and also prevent further axonal loss and neurodegeneration in MS due to trophic effects of myelin. The study of remyelination has advanced dramatically in the last several years such that a number of pathways inhibiting remyelination have been discovered, including those involving LINGO-1, Notch-1, hyaluronan, retinoid X receptor, and wnt/ß-catenin. Other approaches such as high throughput drug screening for remyelination drugs have caught fire, with identification of dozens of known drugs with oligodendrocyte maturation stimulatory effects. Several drugs identified through screens and other mechanisms are in the process of being further evaluated for remyelination in MS and MS models. We discuss the potential molecular targets and the variety of mechanisms towards drug identification and development in remyelination for MS.

JC virus reactivation during prolonged natalizumab monotherapy for multiple sclerosis

OBJECTIVE

To determine the prevalence of JC virus (JCV) reactivation and JCV-specific cellular immune response during prolonged natalizumab treatment for multiple sclerosis (MS).

METHODS

We enrolled 43 JCV-seropositive MS patients, including 32 on natalizumab monotherapy >18 months, 6 on interferon β-1a monotherapy >36 months, and 5 untreated controls. We performed quantitative real-time polymerase chain reaction in cerebrospinal fluid (CSF), blood, and urine for JCV DNA, and we determined JCV-specific T-cell responses using enzyme-linked immunosorbent spot (ELISpot) and intracellular cytokine staining (ICS) assays, ex vivo and after in vitro stimulation with JCV peptides.

RESULTS

JCV DNA was detected in the CSF of 2 of 27 (7.4%) natalizumab-treated MS patients who had no symptoms or magnetic resonance imaging-detected lesions consistent with progressive multifocal leukoencephalopathy. JCV DNA was detected in blood of 12 of 43 (27.9%) and in urine of 11 of 43 (25.6%) subjects without a difference between natalizumab-treated patients and controls. JC viral load was higher in CD34(+) cells and in monocytes compared to other subpopulations. ICS was more sensitive than ELISpot. JCV-specific T-cell responses, mediated by both CD4(+) and CD8(+) T lymphocytes, were detected more frequently after in vitro stimulation. JCV-specific CD4(+) T cells were detected ex vivo more frequently in MS patients with JCV DNA in CD34(+) (p = 0.05) and B cells (p = 0.03).

INTERPRETATION

Asymptomatic JCV reactivation may occur in CSF of natalizumab-treated MS patients. JCV DNA load is higher in circulating CD34(+) cells and monocytes compared to other mononuclear cells, and JCV in blood might trigger a JCV-specific CD4(+) T-cell response. JCV-specific cellular immune response is highly prevalent in all JCV-seropositive MS patients, regardless of treatment.

A clear and present danger: endogenous ligands of Toll-like receptors

Neurologic disease promoted by microbial pathogens, sterile injury, or neurodegeneration rapidly induces innate immunity in adjacent healthy tissue, which in turn contributes extensively to neurologic injury. With more recent focus on innate immune processes, it appears that necrotic, but not apoptotic, death mechanisms provoke inflammatory responses likely due to the release or production of endogenous ligands that activate resident immune cells of the central nervous system. These ligands comprise a diverse set of proteins, nucleic acids, and glycosaminoglycans, including heat shock proteins, HMGB1, RNA, DNA, hyaluronan, and heparin sulfate, that stimulate innate immune mechanisms largely through Toll-like receptors (TLRs). The blockade of interactions between endogenous ligands and TLRs may enable neuroprotective therapeutic strategies for a variety of neurologic diseases.

Toll-like receptor 8 functions as a negative regulator of neurite outgrowth and inducer of neuronal apoptosis

Toll receptors in Drosophila melanogaster function in morphogenesis and host defense. Mammalian orthologues of Toll, the Toll-like receptors (TLRs), have been studied extensively for their essential functions in controlling innate and adaptive immune responses. We report that TLR8 is dynamically expressed during mouse brain development and localizes to neurons and axons. Agonist stimulation of TLR8 in cultured cortical neurons causes inhibition of neurite outgrowth and induces apoptosis in a dissociable manner. Our evidence indicates that such TLR8-mediated neuronal responses do not involve the canonical TLR–NF-κB signaling pathway. These findings reveal novel functions for TLR8 in the mammalian nervous system that are distinct from the classical role of TLRs in immunity.

WAVE1 is required for oligodendrocyte morphogenesis and normal CNS myelination

Myelin formation involves the outgrowth of an oligodendrocyte cell process that can be regarded as a giant lamellipodium because it is an actively growing structure with extruded cytoplasm. The actin cytoskeleton is critical to morphogenesis, but little is known about regulation of actin dynamics in oligodendrocytes. Wiskott-Aldrich syndrome protein family verprolin homologous (WAVE) proteins mediate lamellipodia formation; thus, we asked whether these proteins function in oligodendrocyte process formation and myelination. Here, we show that WAVE1 is expressed by oligodendrocytes and localizes to the lamella leading edge where actin polymerization is actively regulated. CNS WAVE1 expression increases at the onset of myelination. Expression of dominant-negative WAVE1 impaired process outgrowth and lamellipodia formation in cultured oligodendrocytes. Similarly, oligodendrocytes isolated from mice lacking WAVE1 had fewer processes compared with controls, whereas neurons and astrocytes exhibited normal morphology. In white matter of WAVE1-/- mice, we found regional hypomyelination in the corpus callosum and to a lesser extent in the optic nerve. In optic nerve from WAVE1-/- mice, there were fewer nodes of Ranvier but nodal morphology was normal, implicating a defect in myelin formation. Our in vitro findings support a developmentally dynamic and cell-autonomous role for WAVE1 in regulating process formation in oligodendrocytes. Additionally, WAVE1 function during CNS myelination appears to be linked to regional cues. Although its loss can be compensated for in many CNS regions, WAVE1 is clearly required for normal amounts of myelin to form in corpus callosum and optic nerve. Together, these data demonstrate a role for WAVE1 in oligodendrocyte morphogenesis and myelination.

Age-dependent myelin degeneration and proteolysis of oligodendrocyte proteins is associated with the activation of calpain-1 in the rhesus monkey

Myelin provides important insulating properties to axons allowing for propagation of action potentials over large distances at high velocity. Disruption of the myelin sheath could therefore contribute to cognitive impairment, such as that observed during the normal aging process. In the present study, age-related changes in myelin, myelin proteins and oligodendrocyte proteins were assessed in relationship to calpain-1 expression and cognition in the rhesus monkey. Isolation of myelin fractions from brain white matter revealed that as the content of the intact myelin fraction decreased with age, there was a corresponding increase in the floating or degraded myelin fraction, suggesting an increased breakdown of intact myelin with age. Of the myelin proteins examined, only the myelin-associated glycoprotein decreased with age. Levels of the oligodendrocyte-specific proteins 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and myelin/oligodendrocyte-specific protein (MOSP) increased dramatically in white matter homogenates and myelin with age. Age-related increases in degraded CNPase also were demonstrable in white matter in association with increases in activated calpain-1. Degraded CNPase was also detectable in myelin fractions, with only the floating fraction containing activated calpain-1. The increases in the activated enzyme in white matter were much greater than those found in myelin fractions suggesting a source other than the myelin membrane for the marked overexpression of activated calpain-1 with age. In addition, CNPase was demonstrated to be a substrate for calpain in vitro. In summary, changes in myelin and oligodendrocyte proteins occur with age, and they appear to have a significant relationship to cognitive impairment. The overexpression of CNPase and MOSP suggests new formation of myelin by oligodendrocytes, which may occur in response to myelin degradation and injury caused by proteolytic enzymes such as calpain.

Astrocytic hypertrophy and altered GFAP degradation with age in subcortical white matter of the rhesus monkey

Reactive astrocytosis is a well known phenomenon that occurs in the normal aging process of the brain. While many studies indicate astrocytic hypertrophy and glial fibrillary acidic protein (GFAP) content increase with age in the hippocampal formation of certain animal models, it is unclear whether these findings are generalizable to the primate and to other areas of the brain. In this study, we quantitatively assessed age-related changes in astrocytic cell size and density in a rhesus monkey model of normal aging. By GFAP immunohistochemistry, we observed an increase in GFAP(+) cell size but not density in all subcortical white matter areas of the frontal, temporal, and parietal cortices. No significant increases in astrocyte hypertrophy were observed in any gray matter area examined. In addition, Western blotting experiments showed increases in total and degraded GFAP content with age, suggesting altered degradation and possibly production of GFAP occur with age.

Increased microglial activation and protein nitration in white matter of the aging monkey

Activated microglia are important pathological features of a variety of neurological diseases, including the normal aging process of the brain. Here, we quantified the level of microglial activation in the aging rhesus monkey using antibodies to HLA-DR and inducible nitric oxide synthase (iNOS). We observed that 3 out of 5 white matter areas but only 1 of 4 cortical gray matter regions examined showed significant increases in two measures of activated microglia with age, indicating that diffuse white matter microglial activation without significant gray matter involvement occurs with age. Substantial levels of iNOS and 3-nitrotyrosine, a marker for peroxynitrite, increased diffusely throughout subcortical white matter with age, suggesting a potential role of nitric oxide in age-related white matter injury. In addition, we found that the density of activated microglia in the subcortical white matter of the cingulate gyrus and the corpus callosum was significantly elevated with cognitive impairment in elderly monkeys. This study suggests that microglial activation increases in white matter with age and that these increases may reflect the role of activated microglia in the general pathogenesis of normal brain aging.

Metalloendopeptidase EC 3.4.24.15 is necessary for Alzheimer's amyloid-beta peptide degradation

We have investigated the functional relationship between metalloendopeptidase EC 3.4.24.15 (MP24.15) and the amyloid precursor protein involved in Alzheimer's disease (AD) and discovered that the enzyme promotes Abeta degradation. We show here that conditioned medium (CM) of MP24.15 antisense-transfected SKNMC neuroblastoma has significantly higher levels of Abeta. Furthermore, synthetic-Abeta degradation was increased or decreased following incubation with CM of sense or antisense-transfected cells, respectively. Soluble Abeta1-42 was degraded more slowly than soluble Abeta1-40, while aggregated Abeta1-42 showed almost no degradation. Pretreatment of CM with serine proteinase inhibitors 4-(2-aminoethyl)benzenesulfonyl fluoride and diisopropyl fluorophosphate completely inhibited Abeta degradation. Additionally, alpha1-antichymotrypsin (ACT), a serpin family inhibitor tightly associated with plaques and elevated in AD brain, blocked up to 60% of Abeta degradation. Interestingly, incubation of CM of MP24. 15-overexpressing cells with ACT formed an SDS-resistant ACT complex, suggesting an ACT-serine proteinase interaction. Recombinant MP24. 15 alone did not degrade Abeta. 14C-Diisopropyl fluorophosphate-radiolabeled CM from MP24.15-overexpressing cells contained increased levels of several active serine proteinases, suggesting that MP24.15 activates one or more Abeta-degrading serine proteases. Thus, ACT may cause Abeta accumulation by inhibiting an Abeta-degrading enzyme or by direct binding to Abeta, rendering it degradation-resistant. Identification of the Abeta-degrading enzyme and MP24.15's role in its activation is underway. Pharmacological modulation of either enzyme may provide a means of regulating Abeta in the brain.

Lack of correlation between plaque burden and cognition in the aged monkey

To assess whether amyloid plaque accumulation in the monkey brain can account for age-related cognitive impairment that begins at about 20 years of age, we measured plaque content in the brains of 14 rhesus monkeys aged 5-30 years. We used immunohistochemistry employing the monoclonal antibody 6E10, which is specific to amino acids 1-17 of the amyloid beta peptide to identify amyloid plaques in serial coronal sections of the forebrain. Amyloid plaques accumulate with age, starting at 25 years of age and escalating after 30 years. Until the age of 30, plaques are only found in a few monkeys and are relatively sparse. Results from our group and others show that plaque content and the proportion of individuals afflicted with amyloid plaques increase with age. Although both cognitive dysfunction and plaque content increase with age, amyloid plaque content does not correlate with the cognitive dysfunction observed in elderly monkeys since even in very old subjects some cognitively impaired animals have few amyloid plaques and others with abundant plaques show only minor cognitive impairments. In summary, amyloid plaques appear to accumulate significantly only in monkeys over 25 years of age but do not appear to be a causal factor in age-related cognitive decline of the normal aging rhesus monkey.

Evidence for local production of acute phase response apolipoprotein serum amyloid A in Alzheimer's disease brain

Acute phase serum amyloid A (A-apoSAA), but not constitutive apoSAA (C-apoSAA), was identified by Western blotting experiments in brain protein extracts from eight of nine patients with Alzheimer's disease (AD), one with a brain tumor and one with multiple sclerosis. A-apoSAA was not detected in six subjects with Pick's or Lewy Body disease or three other non-AD brain specimens. Apolipoprotein A-I and albumin were not found in any of the brain protein extracts. A-apoSAA mRNA was detected in AD brain by reverse transcription-polymerase chain reaction (RT-PCR). These data suggest that apoSAA is locally produced in AD brain and that investigation of the neuroinflammatory effects of this injury specific apolipoprotein is warranted.

Offenses and defenses against patients: a psychoanalyst's view of the borderline between empathic failure and malpractice

The behaviour of physicians is increasingly coming under scrutiny and attack, both from patients and from institutions that represent the public interest. This social process is partly a necessary and healthy quest for healing and partly a retaliatory response to inevitable failures on the part of physicians to live up to the standards expected of them. The process can assume such ruthless and pervasive forms that physicians are becoming exposed to impossible demands and even abuse at the hands of those they are trying to help. As a result, many physicians become defensive, withdrawing from patient care or reasserting their own needs in regressive ways that further offend or injure their patients. This increases public anxiety and outrage resulting in regressive and even violent "solutions", creating a vicious cycle in which mutual trust and respect is eroded and true health eludes our grasp. Physicians who practise psychotherapy are particularly aware of such regressive emotional pressures and therefore their experience can be taken as a bellwether of social change. Stirred by recent encounters with colleagues who have undergone public inquisition, humiliation and punishment, and drawing on personal clinical experience with patients whose regressive self-expression could at times be considered "borderline", the author attempts to understand the nature of the emotional forces being experienced by members of the profession at large. As in therapy, so in social change; the outcome depends on how well we understand, contain and channel the powerful feelings that underlie whatever actions are taken.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac-derived thromboxane A2. An initiating mediator of reperfusion injury?

After crystalloid cardioplegic arrest, cardiac-derived thromboxane A2 may be an important initiating mediator of no-reflow and hemodynamic deterioration during reperfusion because of its potent vasoactive properties. Although previous studies have already documented the increased release of cardiac thromboxane A2 after ischemia, none have studied the effects of cardiac thromboxane A2 on hemodynamics. We therefore tested the ability of cardiac thromboxane A2 to mediate deterioration of coronary flow and functional recovery during reperfusion after global ischemia. Crystalloid-perfused rat hearts that had undergone Langendorff preparation (n = 30) were subjected to 2 hours of global ischemia at 15 degrees C under cardioplegic protection with (n = 15) or without (n = 15) thromboxane A2 receptor antagonist SQ29548. In eight of 15 hearts in each group, preischemic and postischemic aortic flow, coronary flow, cardiac output, heart rate, and stroke work were determined. In the remaining seven hearts in each group, preischemic and postischemic coronary effluent levels of the stable hydrolysis product of thromboxane A2 and thromboxane B2 were determined with radioimmunoassay through the use of nonrecirculating perfusate. At the completion of the experiment, water content was determined by wet weight/dry weight calculations. In a separate group (n = 7) preischemic myocardial water content was determined. Within the group protected by cardioplegic solution alone, postischemic aortic flow, coronary flow, cardiac output, and stroke work were all significantly decreased (p < 0.05) compared with preischemic values (aortic flow, 50.8 +/- 2.7 versus 29.4 +/- 3.3 ml/min; coronary flow, 13.2 +/- 1.3 versus 8.5 +/- 1.3 ml/min; cardiac output, 64.0 +/- 3.8 versus 38.0 +/- 4.4 ml/min; stroke work, 12.5 +/- 0.7 versus 7.1 +/- 0.8 cm H2O.ml). In relation to the group with cardioplegic solution alone, postischemic aortic flow, coronary flow, cardiac output, and stroke work were all significantly greater (p < 0.05) in the group with the receptor antagonist (aortic flow: 49.5 +/- 2.4 versus 29.4 +/- 3.3 ml/min; coronary flow; 12.4 +/- 1.2 versus 8.5 +/- 1.3 ml/min; cardiac output, 62.0 +/- 2.8 versus 38.0 +/- 4.4 ml/min; stroke work, 12.6 +/- 0.8 versus 7.1 +/- 0.8 cm H2O.ml). Overall, postischemic coronary effluent thromboxane B2 levels were greater than preischemic values (105.6 +/- 12.4 versus 69.6 +/- 9.8, p < 0.05) and treatment with the receptor antagonist did not significantly affect postischemic thromboxane B2 levels (92.0 +/- 7.3 versus 82.3 +/- 15.5, p = not significant). Neither ischemia nor treatment with the receptor antagonist significantly affected heart rate.(ABSTRACT TRUNCATED AT 400 WORDS)

Parathyroid adenoma in submucosa of esophagus

We recently excised and examined a parathyroid adenoma that was located in the submucosa of the esophagus. It was discovered when an elevated calcium level was found on a screening chemistry profile. Subsequently, the patient was found to have renal stones. At operation two other small parathyroid glands were identified. A fourth one was not found. Following removal of the adenoma, the patient's calcium level returned to normal and has remained normal for several months.