Demyelinating and thrombotic diseases of the central nervous system: common pathogenic and triggering factors

Anti-MOG Antibody Syndrome and Cerebral Sinovenous Thrombosis: A Cause–Effect Hypothesis

Cerebral venous thrombosis is an uncommon event of stroke in childhood. Its origin is multifactorial and often it manifests with nonspecific symptoms that may overlap with underlying predisposing factors. Anti–myelin oligodendrocyte glycoprotein (MOG) antibody syndrome is a group of recently recognized acquired demyelinating diseases that occur more commonly in children, usually, with a favorable outcome. The association between cerebral venous thrombosis and demyelinating syndrome has been reported but their clinical relationship is matter of debate and various hypotheses have been advanced including intravenous (IV) steroid therapy and/or the consequence of a shared inflammatory-thrombotic process. Herein, we report the case of a child with anti-MOG antibody syndromes who developed a thrombosis of the superior sagittal sinus and of the right Trolard's vein.

Coagulation/Complement Activation and Cerebral Hypoperfusion in Relapsing-Remitting Multiple Sclerosis

Introduction

Multiple sclerosis (MS) is a demyelinating disease of the central nervous system with an underlying immune-mediated and inflammatory pathogenesis. Innate immunity, in addition to the adaptive immune system, plays a relevant role in MS pathogenesis. It represents the immediate non-specific defense against infections through the intrinsic effector mechanism “immunothrombosis” linking inflammation and coagulation. Moreover, decreased cerebral blood volume (CBV), cerebral blood flow (CBF), and prolonged mean transit time (MTT) have been widely demonstrated by MRI in MS patients. We hypothesized that coagulation/complement and platelet activation during MS relapse, likely during viral infections, could be related to CBF decrease. Our specific aims are to evaluate whether there are differences in serum/plasma levels of coagulation/complement factors between relapsing-remitting (RR) MS patients (RRMS) in relapse and those in remission and healthy controls as well as to assess whether brain hemodynamic changes detected by MRI occur in relapse compared with remission. This will allow us to correlate coagulation status with perfusion and demographic/clinical features in MS patients.

Materials and Methods

This is a multi-center, prospective, controlled study. RRMS patients (1° group: 30 patients in relapse; 2° group: 30 patients in remission) and age/sex-matched controls (3° group: 30 subjects) will be enrolled in the study. Patients and controls will be tested for either coagulation/complement (C3, C4, C4a, C9, PT, aPTT, fibrinogen, factor II, VIII, and X, D-dimer, antithrombin, protein C, protein S, von-Willebrand factor), soluble markers of endothelial damage (thrombomodulin, Endothelial Protein C Receptor), antiphospholipid antibodies, lupus anticoagulant, complete blood count, viral serological assays, or microRNA microarray. Patients will undergo dynamic susceptibility contrast-enhanced MRI using a 3.0-T scanner to evaluate CBF, CBV, MTT, lesion number, and volume.

Statistical Analysis

ANOVA and unpaired t-tests will be used. The level of significance was set at p ≤ 0.05.

Discussion

Identifying a link between activation of coagulation/complement system and cerebral hypoperfusion could improve the identification of novel molecular and/or imaging biomarkers and targets, leading to the development of new effective therapeutic strategies in MS.

Clinical Trial Registration

Clinicaltrials.gov, identifier NCT04380220.

An Uncommon Diagnosis in a Child Presenting With Double Vision and Imbalance

Acute disseminated encephalomyelitis (ADEM) is exceptionally uncommon, with approximately 3 pediatric cases reported in the United States each year. Given the uncommon nature of ADEM, most of the current data rely heavily on case reports. The overwhelming majority of cases have been reported after an acute viral infection or vaccination. Although up to 90% of cases exhibit full remission after intravenous steroids, those in which treatment is delayed can display debilitating sequelae. Here, we present a case of ADEM in a 7-year-old boy who presented with double vision and imbalance with no recent history of acute viral infections or vaccinations.

A Perspective of Coagulation Dysfunction in Multiple Sclerosis and in Experimental Allergic Encephalomyelitis

A key role of both coagulation and vascular thrombosis has been reported since the first descriptions of multiple sclerosis (MS). Subsequently, the observation of a close concordance between perivascular fibrin(ogen) deposition and the occurrence of clinical signs in experimental allergic encephalomyelitis (EAE), an animal model of MS, led to numerous investigations focused on the role of thrombin and fibrin(ogen). Indeed, the activation of microglia, resident innate immune cells, occurs early after fibrinogen leakage in the pre-demyelinating lesion stage of EAE and MS. Thrombin has both neuroprotective and pro-apoptotic effects according to its concentration. After exposure to high concentrations of thrombin, astrocytes become reactive and lose their neuroprotective and supportive functions, microglia proliferate, and produce reactive oxygen species, IL-1β, and TNFα. Heparin inhibits the thrombin generation and suppresses EAE. Platelets play an important role too. Indeed, in the acute phase of the disease, they begin the inflammatory response in the central nervous system by producing of IL-1alpha and triggering and amplifying the immune response. Their depletion, on the contrary, ameliorates the course of EAE. Finally, it has been proven that the use of several anticoagulant agents can successfully improve EAE. Altogether, these studies highlight the role of the coagulation pathway in the pathophysiology of MS and suggest possible therapeutic targets that may complement existing treatments.

Risk of venous thromboembolism in neuromyelitis optica patients hospitalized for acute relapse

Background:

Neuromyelitis optica spectrum disorder (NMOSD) patients may be at increased risk of venous thromboembolism (VTE) not only due to ambulatory disability but also due to systemic autoimmune and inflammatory mechanisms altering the hemostatic balance.

Objective:

To compare the risk of VTE in NMOSD versus multiple sclerosis (MS) patients hospitalized for acute relapses.

Methods:

Hospital admissions for MS or NMOSD exacerbations were retrospectively identified. Demographics and medical history were recorded. The relationship between visit diagnosis and presence of VTE within 6 weeks of relapse onset was assessed by univariate logistic regression. A multivariate model evaluated the relationship between diagnosis, age, race, gender, body mass index (BMI), disease modifying therapy use, oral corticosteroid use, oral contraceptive use, smoking, length of stay (LOS), and ambulatory status on VTE risk.

Results:

A total of 30 NMOSD patients had 55 hospitalizations; 179 MS patients had 264 hospitalizations. Six NMOSD patients and one MS patient had VTE. NMOSD visits compared to MS visits had an odds ratio (OR) of VTE of 32.2 ( p = 0.002). NMOSD was more likely to be associated with VTE (OR = 17.4; p = 0.01) controlling for age, LOS, and ambulatory disability.

Conclusion:

NMOSD may be a risk factor for VTE. Larger prospective studies are required to confirm this risk and determine implications for prophylaxis.

Secondary Progressive Multiple Sclerosis: Definition and Measurement

Secondary progressive multiple sclerosis (SPMS) is diagnosed retrospectively and involves a clinical course characterized by a progressive accumulation of neurological disability, independent of relapses, following an initial relapsing-remitting (RR) phase. Our incomplete understanding of the pathological mechanisms underlying neurodegeneration in multiple sclerosis (MS) may explain why, to date, there is no definitive imaging or laboratory test that is able to inform us when the disease is clearly entering into a progressive phase and why the vast majority of clinical trials testing immunosuppressant and immunomodulating drugs in SPMS patients has so far yielded disappointing or mixed results. Here we discuss the definition(s) of SPMS and how it may vary, outcome measurements (current and emerging) and modern trial design.

Is the Motor System Necessary for Processing Action and Abstract Emotion Words? Evidence from Focal Brain Lesions

Neuroimaging and neuropsychological experiments suggest that modality-preferential cortices, including motor- and somatosensory areas, contribute to the semantic processing of action related concrete words. Still, a possible role of sensorimotor areas in processing abstract meaning remains under debate. Recent fMRI studies indicate an involvement of the left sensorimotor cortex in the processing of abstract-emotional words (e.g., "love") which resembles activation patterns seen for action words. But are the activated areas indeed necessary for processing action-related and abstract words? The current study now investigates word processing in two patients suffering from focal brain lesion in the left frontocentral motor system. A speeded Lexical Decision Task on meticulously matched word groups showed that the recognition of nouns from different semantic categories - related to food, animals, tools, and abstract-emotional concepts - was differentially affected. Whereas patient HS with a lesion in dorsolateral central sensorimotor systems next to the hand area showed a category-specific deficit in recognizing tool words, patient CA suffering from lesion centered in the left supplementary motor area was primarily impaired in abstract-emotional word processing. These results point to a causal role of the motor cortex in the semantic processing of both action-related object concepts and abstract-emotional concepts and therefore suggest that the motor areas previously found active in action-related and abstract word processing can serve a meaning-specific necessary role in word recognition. The category-specific nature of the observed dissociations is difficult to reconcile with the idea that sensorimotor systems are somehow peripheral or 'epiphenomenal' to meaning and concept processing. Rather, our results are consistent with the claim that cognition is grounded in action and perception and based on distributed action perception circuits reaching into modality-preferential cortex.

Correlation Between Daam2 Expression Changes and Demyelination in Guillain-Barre Syndrome

Wnt signaling has been implicated in developmental and regenerative myelination of the CNS and PNS. The present translational investigation was undertaken to assess whether a soluble factor like Wnt may be responsible for the critically important skeletal muscle neuromuscular junction-Schwann cell communication. Specifically, three key aspects were examined: (a) whether the expression of Daam2, disheveled-associated activator of morphogenesis, a key Wnt signaling downstream effector, and PIP5K is changed in the demyelinating conditions and under different stages of progress of clinical recovery of patients with Guillain-Barre syndrome; (b) whether critical protein interactions of Daam2 with disheveled and Arf6 are changed; and (c) whether expression of c-Jun/Krox, a key negative regulator of remyelination, is changed. Daam2 was elevated in acute presentation in GB syndrome. Reduction occurred with clinical improvement of the patients. With progressive clinical improvement, c-Jun/Krox expression significantly reduced with time. Wnt signaling likely causes immediate early gene activation and transcriptional shutdown of factors critical for formation and maintenance of myelination. Whether the findings of the present study are specific to pathophysiology of demyelination in acute infectious polyradiculopathy and multiple sclerosis or a generalized aspect of demyelinating diseases merits to be examined in future studies.