Multiple Sclerosis Disease Process Research Articles

Causal Effect of Genetic Variants Associated With Body Mass Index on Multiple Sclerosis Susceptibility.

Multiple sclerosis (MS) is an autoimmune disease with both genetic and environmental risk factors. Recent studies indicate that childhood and adolescent obesity double the risk of MS, but this association may reflect unmeasured confounders rather than causal effects of obesity. We used separate-sample Mendelian randomization to estimate the causal effect of body mass index (BMI) on susceptibility to MS. Using data from non-Hispanic white members of the Kaiser Permanente Medical Care Plan of Northern California (KPNC) (2006-2014; 1,104 cases of MS and 10,536 controls) and a replication data set from Sweden (the Epidemiological Investigation of MS (EIMS) and the Genes and Environment in MS (GEMS) studies, 2005-2013; 5,133 MS cases and 4,718 controls), we constructed a weighted genetic risk score using 97 variants previously established to predict BMI. Results were adjusted for birth year, sex, education, smoking status, ancestry, and genetic predictors of MS. Estimates in KPNC and Swedish data sets suggested that higher genetically induced BMI predicted greater susceptibility to MS (odds ratio=1.13, 95% confidence interval: 1.04, 1.22 for the KPNC sample; odds ratio = 1.09, 95% confidence interval: 1.03, 1.15 for the Swedish sample). Although the mechanism remains unclear, to our knowledge, these findings support a causal effect of increased BMI on susceptibility to MS for the first time, and they suggest a role for inflammatory pathways that characterize both obesity and the MS disease process.

Evidence Based Therapeutic Exercise Recommendations for Patients with Multiple Sclerosis: A Physical Therapy Approach

Multiple Sclerosis (MS) is a chronic demyelinating disease of the central nervous system affecting over a million people worldwide. The demyelinating process begins when inflammatory T cells of the immune system attack the oligodendrocytes after infiltrating the blood-brain barrier, creating a cascade effect of neurological symptoms. MS presents itself through physical symptoms including fatigue, depressed mood and motor deficits. Current research has shown promise in using exercise intervention to curb the symptoms of this autoimmune disease. This brief review evaluated studies that utilized exercise to decrease fatigue, improve quality of life (QoL), and improve ability to perform activities of daily living. Assessments utilized to examine efficacy of exercise include the Fatigue Severity Scale, Multidimentional Fatigue Inventory-20, and the Major Depression Inventory. These tests provide both an objective and subjective view of the MS disease process. The purpose of this review is to provide information related to resistance exercise recommendations for physical therapists to use as a guide when prescribing exercise interventions to patients with MS. The training program aims to reduce mobility related impairments, decrease fatigue and improve QoL in individuals with MS. After review of this article the reader should ascertain a newfound comfort and knowledge for delivering progressive resistance training to persons with MS. This guide provides both novice and intermediate-advanced recommendations for exercise. The exercise recommendations are indicated for patients with less than or equal to a 6.0 on the Expanded Disability Status Scale. MS patients should consult a physician before actively engaging in any exercise program.

Role of T cell-glial cell interactions in creating and amplifying central nervous system inflammation and multiple sclerosis disease symptoms.

Multiple Sclerosis (MS) is an inflammatory disease of the Central Nervous System (CNS) that causes the demyelination of nerve cells and destroys oligodendrocytes, neurons and axons. Historically, MS has been thought of as a T cell-mediated autoimmune disease of CNS white matter. However, recent studies have identified gray matter lesions in MS patients, suggesting that CNS antigens other than myelin proteins may be involved during the MS disease process. We have recently found that T cells targeting astrocyte-specific antigens can drive unique aspects of inflammatory CNS autoimmunity, including the targeting of gray matter and white matter of the brain and inducing heterogeneous clinical disease courses. In addition to being a target of T cells, astrocytes play a critical role in propagating the inflammatory response within the CNS induced NF-κB signaling. Here, we will discuss the pathophysiology of CNS inflammation mediated by T cell—glial cell interactions and its contributions to CNS autoimmunity.

Aspirin and multiple sclerosis.

Aspirin is widely used to lessen the risks of cardiovascular events. Some studies suggest that patients with multiple sclerosis have an increased risk for some cardiovascular events, for example, venous thromboembolism and perhaps ischemic strokes, raising the possibility that aspirin could lessen these increased risks in this population or subgroups (patients with limited mobility and/or antiphospholipid antibodies). However, aspirin causes a small increased risk of hemorrhagic stroke, which is a concern as it could potentially worsen a compromised blood-brain barrier. Aspirin has the potential to ameliorate the disease process in multiple sclerosis (for example, by limiting some components of inflammation), but aspirin also has the potential to inhibit mitochondrial complex I activity, which is already reduced in multiple sclerosis. In an experimental setting of a cerebral ischemic lesion, aspirin promoted the proliferation and/or differentiation of oligodendrocyte precursors, raising the possibility that aspirin could facilitate remyelination efforts in multiple sclerosis. Other actions by aspirin may lead to small improvements of some symptoms (for example, lessening fatigue). Here we consider potential benefits and risks of aspirin usage by patients with multiple sclerosis.

Daclizumab reverses intrathecal immune cell abnormalities in multiple sclerosis.

ObjectiveNovel treatments such as natalizumab and fingolimod achieve their therapeutic efficacy in multiple sclerosis (MS) by blocking access of subsets of immune cells into the central nervous system, thus creating nonphysiological intrathecal immunity. In contrast, daclizumab, a humanized monoclonal antibody against the alpha chain of the IL-2 receptor, has a unique mechanism of action with multiple direct effects on innate immunity. As cellular intrathecal abnormalities corresponding to MS have been well defined, we asked how daclizumab therapy affects these immunological hallmarks of the MS disease process.MethodsNineteen subpopulations of immune cells were assessed in a blinded fashion in the blood and 50-fold concentrated cerebrospinal fluid (CSF) cell pellet in 32 patients with untreated relapsing-remitting MS (RRMS), 22 daclizumab-treated RRMS patients, and 11 healthy donors (HDs) using 12-color flow cytometry.ResultsLong-term daclizumab therapy normalized all immunophenotyping abnormalities differentiating untreated RRMS patients from HDs. Specifically, strong enrichment of adaptive immune cells (CD4+ and CD8+ T cells and B cells) in the CSF was reversed. Similarly, daclizumab controlled MS-related increases in the innate lymphoid cells (ILCs) and lymphoid tissue inducer cells in the blood and CSF, and reverted the diminished proportion of intrathecal monocytes. The only marker that distinguished daclizumab-treated MS patients from HDs was the expansion of immunoregulatory CD56bright NK cells.InterpretationNormalization of immunological abnormalities associated with MS by long-term daclizumab therapy suggests that this drug's effects on ILCs, NK cells, and dendritic cell-mediated antigen presentation to CD4+ and CD8+ T cells are critical in regulating the MS disease process.

Serum proteomics in multiple sclerosis disease progression.

A hallmark of multiple sclerosis is the unpredictable disease course (progression). There are currently no clinically useful biomarkers of MS disease progression; most work has focused on the analysis of CSF, which requires an invasive procedure. Here, we explore the potential of proteomics to identify panels of serum biomarkers of disease progression in MS. By comparing the protein signatures of two challenging to obtain, but well-defined, MS phenotypic groups at the extremes of progression (benign and aggressive cases of MS), we identified proteins that encompass processes related to inflammation, opsonization, and complement activation. Findings require validation, but are an important step on the pathway to clinically useful biomarker discovery. This article is part of a Special Issue entitled: Protein dynamics in health and disease. Guest Editors: Pierre Thibault and Anne-Claude Gingras.

A complex role of herpes viruses in the disease process of multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system (CNS). Neither the antigenic target(s) nor the cell population(s) responsible for CNS tissue destruction in MS have been fully defined. The objective of this study was to simultaneously determine the antigen (Ag)-specificity and phenotype of un-manipulated intrathecal CD4+ and CD8+ T cells of patients with relapsing-remitting and progressive MS compared to subjects with other inflammatory neurological diseases. We applied a novel Ag-recognition assay based on co-cultures of freshly obtained cerebrospinal fluid T cells and autologous dendritic cells pre-loaded with complex candidate Ag's. We observed comparably low T cell responses to complex auto-Ag's including human myelin, brain homogenate, and cell lysates of apoptotically modified oligodendroglial and neuronal cells in all cohorts and both compartments. Conversely, we detected a strong intrathecal enrichment of Epstein-Barr virus- and human herpes virus 6-specific (but not cytomegalovirus-specific) reactivities of the Th1-phenotype throughout all patients. Qualitatively, the intrathecal enrichment of herpes virus reactivities was more pronounced in MS patients. This enrichment was completely reversed by long-term treatment with the IL-2 modulating antibody daclizumab, which strongly inhibits MS disease activity. Finally, we observed a striking discrepancy between diminished intrathecal T cell proliferation and enhanced cytokine production of herpes virus-specific T cells among progressive MS patients, consistent with the phenotype of terminally differentiated cells. The data suggest that intrathecal administration of novel therapeutic agents targeting immune cells outside of the proliferation cycle may be necessary to effectively eliminate intrathecal inflammation in progressive MS.

Managing treatment fatigue in patients with multiple sclerosis on long-term therapy: the role of multiple sclerosis nurses.

This article discusses the many ways that nurses can address the factors that lead to treatment fatigue in patients with multiple sclerosis (MS) on long-term disease-modifying therapy, ultimately helping to preserve the patient’s health and quality of life. Patients with MS on long-term therapy may suffer from treatment fatigue and poor adherence due to a variety of different factors, including difficulties with injections, anxiety/depression, financial problems, and inaccurate beliefs about the MS disease process. Because MS nurses have regular interactions with patients, they are ideally situated to help patients cope with these and other factors that may limit adherence.

Current and future drugs for treatment of MS-associated bladder dysfunction

A majority of patients diagnosed with multiple sclerosis (MS) will develop lower urinary tract symptoms (LUTS) during the course of the disease. Even if antimuscarinic (anticholinergic) treatment is currently the mainstay of conservative treatment of neurogenic detrusor overactivity (NDO), including MS-induced NDO, extensive data regarding their effectiveness and safeness are lacking. When antimuscarinic medications fail to prove efficacious, a further option is intradetrusor injections of onabotulinumtoxin A. In several studies, more than half (and up 76%) of the patients treated with onabotulinumtoxin A experienced significant improvement in symptoms or even achieved complete continence. Cannabis extracts have shown some promise but has still not gained wide acceptance as an effective treatment. Over the last few years many new disease-modifying drugs that have been approved and introduced for treatment of MS. These drugs may have effects not only on the MS disease process, but also on the disease symptoms, including LUTS. However, MS is not primarily a bladder disease and treatment of the underlying pathophysiology should be the main goal of treatment. Since most of the urology drugs are targeting LUTS, these drugs should be regarded as “adds on” to treatments modifying the underlying disorder. Considering that most of these drugs have not been studied specifically with respect to efficacy on LUTS, and since they are not without significant side effects, it seems important that if and when they are going to be used for treatment of bladder symptoms should be a joint decision between the neurologist and urologist taking care of the patient.

Gathering thunder.

It's common to accompany the rollout of a new biomedical journal with an explanation for its coming into being, usually by suggesting there's an unmet need, despite the panoply of existing journals. I'm not going to do that, at least not exactly. The biomedical literature is almost unimaginably vast already, much more than even the most diligent speed-reading scholar-who-listens-to-science-blogs-in-her-sleep can keep up with. Our hope is not, therefore, to provide a place to publish papers that have no other home. There are manifold other venues and more each day. Instead, our intention is to provide a single source of vital information for a growing community of translational physicians and scientists who sense a unique moment in the development of the field of inquiry at which neurobiology and immunology intersect. From the perspective of those interested in neurodegeneration, recent reports firmly implicating genes whose sole action relates to inflammation in Alzheimer disease pathogenesis came as a thunderclap. Inflammatory neuromuscular disease now features a wide spectrum of autoantibodies, ranging from tRNA synthetase antibodies in myositis to ganglioside antibodies in the acute demyelinating polyradiculoneuropathy syndromes. These antibodies are used to help classify syndromes and provide pathophysiologic insights. Antibodies have also swarmed into the CNS, with many targeting neurotransmitter receptors and other surface determinants, including NMDARs, AMPARs, mGluRs, glycine receptors, GABA receptors, Caspr2, and LGI1, among several others. Antibody discovery made possible new insights into diagnosis and treatment of neuromyelitis optica (NMO), a recognized entity for more than 100 years. Multiple sclerosis (MS) has become a treatable condition in its early phase and has seen transformative insights emerge from decades of genetic and epidemiologic research. Despite this remarkable progress, we’re still uncertain how the MS disease process causes its myriad of symptoms and how to deploy the varied therapeutics available to us. Neuroinfectious disease stands in many ways at the epicenter of the immunology/neuroscience junction.

Time matters - acute stress response and glucocorticoid sensitivity in early multiple sclerosis.

Psychosocial stress has frequently been associated with disease activity and acute exacerbations in multiple sclerosis (MS). Despite this well established finding, strikingly little is known about the acute hypothalamic-pituitary-adrenal (HPA) and sympathetic-adrenal-medullary (SAM) stress response in MS. Twenty-six early relapsing-remitting MS (RRMS) patients and seventeen age- and sex-matched healthy control subjects (CS) took part in the Trier Social Stress Test (TSST), a well validated psycho-social laboratory stress protocol. Repeated blood samples were analyzed for stress-related cortisol and catecholamine levels as well as for glucocorticoid sensitivity (GCS) of target immune cells. Chronic and acute stress appraisals were assessed by self-report measures. RRMS patients and CS did not differ in stress-related cortisol/catecholamine levels, GCS or stress appraisal in response to the TSST. However, cortisol release as well as GCS was strongly correlated with time since diagnosis but not with neurological disability. Patients with shorter disease duration (2-12 months) expressed a significantly higher cortisol stress response while MS patients with longer disease duration (14-36 months) showed a significantly diminished HPA response as well as lower post-stress GCS. There is evidence for a time-dependent variability in the HPA stress system with an increased cortisol stress response in the first year after diagnosis along with a more blunted HPA stress response and a diminished GCS in subsequent disease stages. Data underscore the highly dynamic nature of HPA axis regulation in the MS disease process, which could possibly relate to compensatory mechanisms within a cytokine-HPA axis feedback circuit model.

Understanding disease processes in multiple sclerosis through magnetic resonance imaging studies in animal models

There are exciting new advances in multiple sclerosis (MS) resulting in a growing understanding of both the complexity of the disorder and the relative involvement of grey matter, white matter and inflammation. Increasing need for preclinical imaging is anticipated, as animal models provide insights into the pathophysiology of the disease. Magnetic resonance (MR) is the key imaging tool used to diagnose and to monitor disease progression in MS, and thus will be a cornerstone for future research. Although gadolinium-enhancing and T2 lesions on MRI have been useful for detecting MS pathology, they are not correlative of disability. Therefore, new MRI methods are needed. Such methods require validation in animal models. The increasing necessity for MRI of animal models makes it critical and timely to understand what research has been conducted in this area and what potential there is for use of MRI in preclinical models of MS. Here, we provide a review of MRI and magnetic resonance spectroscopy (MRS) studies that have been carried out in animal models of MS that focus on pathology. We compare the MRI phenotypes of animals and patients and provide advice on how best to use animal MR studies to increase our understanding of the linkages between MR and pathology in patients. This review describes how MRI studies of animal models have been, and will continue to be, used in the ongoing effort to understand MS.

Multiple sclerosis: Prospects and promise

We have entered a golden era in multiple sclerosis (MS) research. Two decades ago, our understanding of the disease was largely descriptive and there were no approved therapies to modify the natural history of MS. Today, delineation of immune pathways relevant to MS have been clarified; a comprehensive map of genes that influence risk compiled; clues to environmental triggers identified; noninvasive in vivo monitoring of the MS disease process has been revolutionized by high-field MRI; and many effective therapies for the early, relapsing, component of MS now exist. However, major challenges remain. We still have no useful treatment for progressive MS (the holy grail of MS research), no means to repair injured axons or protect neurons, and extremely limited evidence to guide treatment decisions. Recent advances have set in place a foundation for development of increasingly selective immunotherapy for patients; application of genetic and genomic discoveries to improve therapeutic options; development of remyelination or neuroprotection therapies for progressive MS; and integrating clinical, imaging and genomic data for personalized medicine. MS has now advanced from the backwaters of autoimmune disease research to the front-line, and definitive answers, including cures, are now realistic goals for the next decade. Many of the breakthrough discoveries in MS have also resulted from meaningful interactions across disciplines, and especially from translational and basic scientists working closely with clinicians, highlighting that the clinical value of discoveries are most often revealed when ideas developed in the laboratory are tested at the bedside.

Pathology of Multiple Sclerosis

This article summarizes the pathologic features of multiple sclerosis (MS) and other inflammatory demyelinating diseases and discusses neuropathologic studies that have yielded novel insights into potential mechanisms of demyelination. The pathologic hallmark of MS consists of focal demyelinated plaques within the CNS, with variable degrees of inflammation, gliosis, and neurodegeneration. Active MS lesions show a profound pathologic heterogeneity with four major patterns of immunopathology, suggesting that the targets of injury and mechanisms of demyelination in MS may be different in different disease subgroups. Recent pathologic studies have suggested that the subarachnoid space and cortex may be initial sites and targets of the MS disease process, that inflammatory cortical demyelination is present early in MS, and that meningeal inflammation may drive cortical and white matter injury in some MS patients. MS is heterogeneous with respect to clinical, genetic, radiographic, and pathologic features; surrogate MRI, clinical, genetic, serologic, and/or CSF markers for each of the four immunopatterns need to be developed in order to recognize them in the general nonbiopsied MS population. Inflammatory cortical demyelination is an important early event in the pathogenesis of MS and may be driven by meningeal inflammation. These observations stress the importance of developing imaging techniques able to capture early inflammatory cortical demyelination in order to better understand the disease pathogenesis and to determine the impact of potential disease-modifying therapies on the cortex.

Imaging new lesions

Since 1981, when multiple sclerosis (MS) lesions were first visualized in vivo using MRI, understanding of MS disease processes has expanded dramatically. Serial postcontrast imaging shows that MS inflammatory activity is much more frequent than clinical relapses1 and that lesion evolution can take different paths.2 In clinical trials, reduction of new lesion formation predicts clinical efficacy of disease-modifying drugs.3 Despite these advances, key questions remain unanswered: What initiates development of an MS lesion? Which lesions represent severe irreversible tissue damage, and which are likely to remyelinate? What is the most sensitive way to detect new lesions?

Blood RNA profiling in a large cohort of multiple sclerosis patients and healthy controls

Multiple sclerosis (MS) is the most common autoimmune disease of the central nervous system (CNS). It is characterized by the infiltration of autoreactive immune cells into the CNS, which target the myelin sheath, leading to the loss of neuronal function. Although it is accepted that MS is a multifactorial disorder with both genetic and environmental factors influencing its development and course, the molecular pathogenesis of MS has not yet been fully elucidated. Here, we studied the longitudinal gene expression profiles of whole-blood RNA from a cohort of 195 MS patients and 66 healthy controls. We analyzed these transcriptomes at both the individual transcript and the biological pathway level. We found 62 transcripts to be significantly up-regulated in MS patients; the expression of 11 of these genes was counter-regulated by interferon treatment, suggesting partial restoration of a 'healthy' gene expression profile. Global pathway analyses linked the proteasome and Wnt signaling to MS disease processes. Since genotypes from a subset of individuals were available, we were able to identify expression quantitative trait loci (eQTL), a number of which involved two genes of the MS gene signature. However, all these eQTL were also present in healthy controls. This study highlights the challenge posed by analyzing transcripts from whole blood and how these can be mitigated by using large, well-characterized cohorts of patients with longitudinal follow-up and multi-modality measurements.

Cytokine/Chemokine Expression in Reflex Tears from Employers Exposed to Computer Screens in a Healthy Office Environment

Neuroantigen-specific T cells play an important role in the disease process of multiple sclerosis (MS) and experimental allergic encephalomyelitis (EAE). These cells are encephalitogenic and in susceptible animals, these cells alone can cause EAE. However, mechanisms by which encephalitogenicity is controlled are poorly understood. This study underlines the importance of nitric oxide (NO) in the regulation of encephalitogenicity of T cells. Interestingly, reducing NO during myelin basic protein (MBP)-priming of T cells attenuated the ability of these T cells to induce EAE and EAE-associated neuroinflammation and demyelination. Consistently, increasing NO had opposite effect. Similarly scavenging NO reduced the encephalitogenicity of PLP-specific T cells isolated from female PLP-TCR transgenic mice and supplementation of NO broke the tolerance of PLP-specific T cells of male PLP-TCR mice. Reduced encephalitogenicity of neuroantigen-primed T cells isolated from iNOS (-/-) mice compared to that from wild type mice clearly defines an essential role of iNOS-derived NO in controlling the encephalitogenicity of myelin-specific T cells. This study illustrates a novel role of NO in controlling encephalitogenicity of T cells that may participate in the complex pathogenesis of MS.

EDITORIAL

EDITORIAL

Pathogenic CD8 T Cells in Multiple Sclerosis and Its Experimental Models

A growing body of evidence suggests that autoreactive CD8 T cells contribute to the disease process in multiple sclerosis (MS). Lymphocytes in MS plaques are biased toward the CD8 lineage, and MS patients harbor CD8 T cells specific for multiple central nervous system (CNS) antigens. Currently, there are relatively few experimental model systems available to study these pathogenic CD8 T cells in vivo. However, the few studies that have been done characterizing the mechanisms used by CD8 T cells to induce CNS autoimmunity indicate that several of the paradigms of how CD4 T cells mediate CNS autoimmunity do not hold true for CD8 T cells or for patients with MS. Thus, myelin-specific CD4 T cells are likely to be one of several important mechanisms that drive CNS disease in MS patients. The focus of this review is to highlight the current models of pathogenic CNS-reactive CD8 T cells and the molecular mechanisms these lymphocytes use when causing CNS inflammation and damage. Understanding how CNS-reactive CD8 T cells escape tolerance induction and induce CNS autoimmunity is critical to our ability to propose and test new therapies for MS.

Crosstalk between Nitric Oxide and T helper cells

Crosstalk between Nitric Oxide and T helper cells