Body fluid markers for multiple sclerosis and differential diagnosis from atypical demyelinating disorders

INTRODUCTION

Body fluid markers could be helpful to predict the conversion into clinically definite multiple sclerosis (MS) in people with a first demyelinating event of the central nervous system (CNS). Consequently, biomarkers such as oligoclonal bands, which are integrated in the current MS diagnostic criteria, could assist early MS diagnosis.

AREAS COVERED

This review examines existing knowledge on a broad spectrum of body fluid markers in people with a first CNS demyelinating event, explores their potential to predict conversion to MS, to assess MS disease activity, as well as their utility to differentiate MS from atypical demyelinating disorders such as neuromyelitis optica spectrum disorder and myelin oligodendrocyte glycoprotein associated disease.

EXPERT OPINION

This field of research has shown a dramatic increase of evidence, especially in the last decade. Some biomarkers are already established in clinical routine (e.g. oligoclonal bands) while others are currently implemented (e.g. kappa free light chains) or considered as breakthroughs (e.g. neurofilament light). Determination of biomarkers poses challenges for continuous monitoring, especially if exclusively detectable in cerebrospinal fluid. A handful of biomarkers are measurable in blood which holds a significant potential.

Astrocytic phagocytosis of myelin debris and reactive characteristics in vivo and in vitro

BACKGROUND INFORMATION

Persistent myelin debris can inhibit axonal regeneration, thereby hindering remyelination. Effective removal of myelin debris is essential to eliminate the interference of myelin debris in oligodendrocyte progenitor cell (OPC) activation, recruitment to demyelinating sites and/or differentiation into mature oligodendrocytes (OLs). In addition to microglia, it has been reported that astrocytic phagocytosis of myelin debris is a feature of early demyelination.

RESULTS

In the present study, astrocytes effectively phagocytized myelin debris in vitro and in vivo. On the 5th day after injecting myelin debris into the brain, astrocytes were enriched in the area injected with myelin debris compared with microglia, and their ability to engulf myelin debris was stronger than that of microglia. When exposed to myelin debris, astrocytes phagocytizing myelin debris triggered self-apoptosis, accompanied by the activation of NF-κB, down-regulation of Nrf2, and the increase of ciliary neurotrophic factor (CNTF) and basic fibroblast growth factor (bFGF). However, the activation of astrocytic NF-κB did not influence the inflammatory cytokines IL-1β, IL-6, and TNF-α, and the anti-inflammatory factor IL-10. The proliferation of astrocytes and mobilization of OPCs in the subventricular zone were elevated on the 5th day after intracerebral injection of myelin debris.

CONCLUSIONS

The results suggested that myelin phagocytosis of astrocytes should help improve the microenvironment and promote myelin regeneration by increasing CNTF and bFGF within the central nervous system.

SIGNIFICANCE

However, the molecular interaction of astrocytes acting as phagocytes remains to be further explored. Therefore, an improvement of astrocytes to phagocytize myelin debris may be a promising treatment measure to prevent demyelination and promote remyelination in MS and other diseases with prominent myelin injury.

Inpatient Burden of Neurological Disorders: A Route Map for Allocation of Resources and Postgraduate Training

Introduction There are limited data regarding the profile of inpatient neurological disorders in India. Understanding the spectrum of diseases and the profile of patients admitted in an inpatient setting will help to streamline services, allocate resources, develop management protocols, design curricula, and improve training programs of postgraduate students in neurology training. Objective The objective of this study is to study the profile of inpatient neurological disorders in 1000 consecutive patients admitted to a tertiary care neurological center. Methods Data from 1000 consecutive inpatients admitted to the Neurology Department at St. John's Medical College Hospital, Bengaluru from January 2018 to October 2018 were collected from the medical records. The data obtained from the case records were entered into a Microsoft Excel spreadsheet for descriptive analysis. Results The average age of the patients was 48 years (±18.18) and 606 of the 1000 patients were males. Strokes, including arterial and venous strokes, formed the major inpatient caseload, accounting for 48.7% of cases. Of these, 84% had ischemic arterial strokes, 7.4% had intracranial hemorrhage, and 8.4 % had cerebral sinus venous strokes; 19.3% of patients were admitted for seizures while 8.2% of patients were admitted for headache. Meningitis was diagnosed in 5.2% of patients; 4.8% of patients had central nervous system demyelinating and autoimmune diseases. A number of other diagnoses comprised less than 2.5% each and included movement disorders, peripheral nerve, spine and nerve roots disorders, neuromuscular diseases, neurodegenerative diseases, and medical and functional illness. Conclusion The most common disorders in the inpatient setting are stroke, seizure, headache, meningitis, and autoimmune/demyelinating disorders. These disorders should receive priority while planning the allocation of resources, educational curriculum, training, and teaching programs.

Comparison of the Efficacy of Optogenetic Stimulation of Glia versus Neurons in Myelination

Increasing evidence demonstrates that optogenetics contributes to the regulation of brain behavior, cognition, and physiology, particularly during myelination, potentially allowing for the bidirectional modulation of specific cell lines with spatiotemporal accuracy. However, the type of cell to be targeted, namely, glia vs neurons, and the degree to which optogenetically induced cell activity can regulate myelination during the development of the peripheral nervous system (PNS) are still underexplored. Herein, we report the comparison of optogenetic stimulation (OS) of Schwann cells (SCs) and motor neurons (MNs) for activation of myelination in the PNS. Capitalizing on these optogenetic tools, we confirmed that the formation of the myelin sheath was initially promoted more by OS of calcium translocating channelrhodopsin (CatCh)-transfected SCs than by OS of transfected MNs at 7 days in vitro (DIV). Additionally, the level of myelination was substantially enhanced even until 14 DIV. Surprisingly, after OS of SCs, > 91.1% ± 5.9% of cells expressed myelin basic protein, while that of MNs was 67.8% ± 6.1%. The potent effect of OS of SCs was revealed by the increased thickness of the myelin sheath at 14 DIV. Thus, the OS of SCs could highly accelerate myelination, while the OS of MNs only somewhat promoted myelination, indicating a clear direction for the optogenetic application of unique cell types for initiating and promoting myelination. Together, our findings support the importance of precise cell type selection for use in optogenetics, which in turn can be broadly applied to overcome the limitations of optogenetics after injury.

Cognitive Functioning in Patients with Pediatric-Onset Multiple Sclerosis, an Updated Review and Future Focus

Pediatric-onset multiple sclerosis (POMS) is relatively rare, but as technology and neuroimaging advance, an increasing number of cases are identified, and our understanding of how multiple sclerosis (MS) impacts the developing brain improves. There are consistent findings in the literature highlighting the impact of MS and other demyelinating diseases on cognitive functioning and cognitive development. We also have a better understanding of how POMS impacts psychosocial functioning and functional outcomes in daily living. This paper hopes to review findings associated with cognitive and psychosocial functioning in patients with POMS, as well as explore more recent advances in the field and how they relate to cognitive and psychosocial outcomes. We also discuss the ongoing need for future studies with a focus on better understanding deficits and disease correlates, but also preventative measures and potential rehabilitation.

Myelin oligodendrocyte glycoprotein antibody-associated demyelination: comparison between onset phenotypes

BACKGROUND AND PURPOSE

The aim of this study was to analyse the clinical and prognostic features of myelin oligodendrocyte glycoprotein (MOG) antibody-associated demyelination with different onset phenotypes.

METHODS

A total of 52 MOG-IgG-seropositive patients were divided into four groups: (i) optic neuritis (ON) at onset (MOG-ON⁺ , n = 23), (ii) transverse myelitis (TM) at onset (MOG-TM⁺ , n = 12), (iii) pure brain symptoms at onset (MOG-ON^- -TM^- , n = 14) and (iv) both ON and TM at onset (n = 3). This final group was not included in further analyses. Data were collected through medical records and regular follow-up.

RESULTS

Median age at presentation was 24 (range, 3-63) years in the whole cohort (50% female). MOG-ON^- -TM^- patients had the youngest age of onset across the three groups. Patients with MOG-TM⁺ tended to relapse more frequently and had a longer interval to first relapse than was observed in MOG-ON⁺ and MOG-ON^- -TM^- patients. High MOG-IgG titres were associated with increased cerebrospinal fluid leukocytes. The likelihood of harbouring transient, low MOG-IgG titres was higher in the MOG-TM⁺ group than in the other groups. After a median disease duration of 20 months, most but not all cases had a favourable outcome, with 8% developing severe visual deficit, 2% becoming wheelchair-dependent and 6% developing cognitive impairment. The onset phenotype appeared to be an important predictor of disability type. Having high MOG-IgG titres (odds ratio, 0.168, P = 0.027) or female gender (odds ratio, 0.270, P = 0.067) was associated with a lower likelihood of complete recovery.

CONCLUSIONS

Onset phenotype may influence long-term presentation, MOG-IgG status as well as outcome. Further large and prospective studies are needed to better clarify the clinical implications of the first demyelinating event.

Myelopathy

Myelopathy is an inclusive term, referring to pathology leading to a neurologic deficit related to the spinal cord. The clinical diagnosis of myelopathy requires a detailed history and physical examination to define the clinical syndrome. Neuroimaging is indicated in most instances of new-onset myelopathy. It is indicated also when the worsening of a myelopathy is unexplained. Advances in neuroimaging have proved to play a vital role in diagnosis. Appropriate diagnosis and treatment are dependent upon an adequate imaging evaluation to establish the presence of mechanical stability, extrinsic spinal cord compression, or an intramedullary lesion. The most frequent etiology of myelopathy is related to degenerative disease of the spine from osteophyte or extruded disc material causing compression of the spinal cord in the cervical or thoracic spine. The next common etiologies are spinal cord compression due to extradural masses caused by metastatic disease to bone or blunt trauma. In these cases, emergency imaging should be performed to assess the nature of the lesion causing the myelopathy and plan the most appropriate treatment. Also urgent imaging should be performed when an abscess in the spinal canal is suspected. Less urgent is imaging of primary neoplasms of the meninges, roots, or spinal cord, as well as noninfectious inflammatory processes, such as multiple sclerosis, and neurodegenerative, vascular, nutritional, or idiopathic disorders leading to myelopathy. Although a survey of the entire spinal cord can be performed with imaging, it is more appropriate to define from the clinical findings what levels of the spine and spinal cord should be imaged. This approach helps limit the likelihood of false-positive imaging findings that may encourage needless attempts to fix what is not broken. Similarly, the most appropriate imaging study and protocol should be selected in order to provide a timely and accurate diagnosis. To do so requires detailed knowledge regarding the strengths and limitations of the multiple imaging modalities available. This chapter outlines an approach to proper study selection based on the likely etiology of myelopathy from the clinical findings. Chapters 33-39 cover these disorders in detail.

Infection and the etiology and pathogenesis of multiple sclerosis

Multiple sclerosis (MS) currently defies clinical and scientific definitions, and carries a prognosis that remains practically unchanged despite many years of intensive research. Although the prevailing dogma is that MS is an immune-mediated condition, it fulfills none of the criteria of an autoimmune disease. On the other hand, there is enough significant data to suggest that infectious agents(s) could be involved in either direct damage to the white matter or induce inflammatory responses that secondarily affect the brain. Our goal here is to review the data supporting the possibility that infection has a critical role in the disease, examine the list of potential candidates that have been suggested, and outline an approach regarding the potential role of infectious agents in the etiology and pathogenesis of MS.