Update on the diagnosis and treatment of neuromyelits optica spectrum disorders (NMOSD) - revised recommendations of the Neuromyelitis Optica Study Group (NEMOS). Part I: Diagnosis and differential diagnosis

Biomarkers for neuromyelitis optica: a visual analysis of emerging research trends

Neuromyelitis optica is an inflammatory demyelinating disease of the central nervous system that differs from multiple sclerosis. Over the past 20 years, the search for biomarkers for neuromyelitis optica has been ongoing. Here, we used a bibliometric approach to analyze the main research focus in the field of biomarkers for neuromyelitis optica. Research in this area is consistently increasing, with China and the United States leading the way on the number of studies conducted. The Mayo Clinic is a highly reputable institution in the United States, and was identified as the most authoritative institution in this field. Furthermore, Professor Wingerchuk from the Mayo Clinic was the most authoritative expert in this field. Keyword analysis revealed that the terms "neuromyelitis optica" (261 times), "multiple sclerosis" (220 times), "neuromyelitis optica spectrum disorder" (132 times), "aquaporin 4" (99 times), and "optical neuritis" (87 times) were the most frequently used keywords in literature related to this field. Comprehensive analysis of the classical literature showed that the majority of publications provide conclusive research evidence supporting the use of aquaporin-4-IgG and neuromyelitis optica-IgG to effectively diagnose and differentiate neuromyelitis optica from multiple sclerosis. Furthermore, aquaporin-4-IgG has emerged as a highly specific diagnostic biomarker for neuromyelitis optica spectrum disorder. Myelin oligodendrocyte glycoprotein-IgG is a diagnostic biomarker for myelin oligodendrocyte glycoprotein antibody-associated disease. Recent biomarkers for neuromyelitis optica include cerebrospinal fluid immunological biomarkers such as glial fibrillary acidic protein, serum astrocyte damage biomarkers like FAM19A5, serum albumin, and gamma-aminobutyric acid. The latest prospective clinical trials are exploring the potential of these biomarkers. Preliminary results indicate that glial fibrillary acidic protein is emerging as a promising candidate biomarker for neuromyelitis optica spectrum disorder. The ultimate goal of future research is to identify non-invasive biomarkers with high sensitivity, specificity, and safety for the accurate diagnosis of neuromyelitis optica.

Newly emerging type B insulin resistance (TBIR) during treatment with eculizumab for AQP4-IgG-positive neuromyelitis optica spectrum disorder (NMOSD): fatal outcome

BACKGROUND

Aquaporin-4 immunoglobulin G (AQP4-IgG) antibody-positive neuromyelitis optica spectrum disorders (NMOSD) are frequently associated with other autoimmune disorders, including systemic lupus erythematosus (SLE). Eculizumab (ECU) is a highly effective long-term treatment for NMOSD. However, ECU is known to increase significantly the risk of infection with encapsulated bacteria and sepsis. Recently, increased insulin resistance (IR) in patients with NMOSD has been suggested. Type B IR (TBIR) is a rare autoimmune condition often accompanying or preceding SLE. TBIR has not yet been reported in NMOSD.

OBJECTIVE

To report an ECU-treated patient with AQP4-IgG-positive NMOSD who developed fatal septic complications after the emergence of TBIR.

METHODS

Description of the clinical course over a period of 8 years.

RESULTS

A female patient was diagnosed with NMOSD at the age of 16 years. A variety of disease-modifying drugs failed to achieve sufficient disease control, resulting in severe tetraparesis. Treatment with ECU was started 6 years after NMOSD diagnosis and stabilized the disease. The patient developed TBIR 8 months after initiation of ECU therapy. Following high-dose intravenous methylprednisolone therapy for a clinical relapse and three further courses of ECU, the patient was admitted with severe pneumonia caused by the encapsulated bacterium Klebsiella pneumoniae and hypoglycemia. Despite multimodal therapy, the patient died from sepsis-related multiorgan failure 18 months after initiation of ECU.

CONCLUSIONS

TBIR should be considered as differential diagnosis in patients with NMOSD presenting with disturbed glucose metabolism, irrespective of the presence of SLE. More real-world data are needed on the risk/benefit ratio of ECU treatment in patients who have co-existing autoimmune comorbidities that may compromise immune function. Strategies to mitigate the risk of serious infection in patients treated with ECU are discussed.

Dysphagia in neuromyelitis optica spectrum disorder and multiple sclerosis: A comparison of frequency, severity, and effects on quality of life

OVERVIEW

Dysphagia has been previously discussed as a potential life-threatening condition secondary to chronic neurological diseases such as multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). However, its impact on the quality of life (QoL) of patients with NMOSD has never been studied before. This study aims to determine the frequency of dysphagia and its impact on QoL in NMOSD patients in comparison with MS people and healthy individuals.

METHODS

Seventy-five MS and sixty-five NMOSD patients with an expanded disability status scale (EDSS) score ≥ 3.5 in addition to 106 healthy controls were enrolled in this cross-sectional study. All the participants completed the self-report dysphagia in MS (DYMUS) and 36-item short-form health survey (SF-36) questionnaires. In case of positive answers to at least one of the questions in DYMUS, they were asked to fill out the dysphagia handicap index (DHI) questionnaire.

RESULTS

The frequency of dysphagia in NMOSD, MS, and control groups was 61.54 %, 72.97 %, and 27 %, respectively. Patients with swallowing problems had reduced scores across different swallowing-related QoL domains compared to non-dysphagic patients (p < 0.05). NMOSD (1, IQR [0-3.5]) and MS patients (2, IQR [0-4]) had a significantly higher median total DYMUS score than control (0, IQR [0-1]) (p < 0.01). However, there was no discernible difference between the two patient groups. NMOSD had the highest mean total DHI score (21.22 ± 21), followed by MS (15.25 ± 18.94) and control (7.08 ± 5.12). A significant correlation was seen in the NMOSD group between the DHI total score and the SF-36 total score (r = 0.62, p < 0.05). The DHI and SF-36 subscales showed a strong association as well. The overall SF-36 scores in both the control and MS groups was not significantly correlated with DHI. The generalized linear model analysis showed that the NMOSD group's age (p-value = 0.005), EDSS (p-value < 0.001), and total DYMUS score (p-value = 0.018) significantly affected overall health status.

CONCLUSION

The presence of dysphagia significantly impacts the QoL in NMOSD patients, particularly in aspects related to swallowing. These findings underscore the critical need for diligent dysphagia screening and emphasize the importance of educating both caregivers and NMOSD patients about managing this challenging symptom.

Improving the sensitivity of myelin oligodendrocyte glycoprotein-antibody testing: exclusive or predominant MOG-IgG3 seropositivity-a potential diagnostic pitfall in patients with MOG-EM/MOGAD

BACKGROUND

Myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD) is the most important differential diagnosis of both multiple sclerosis and neuromyelitis optica spectrum disorders. A recent proposal for new diagnostic criteria for MOG-EM/MOGAD explicitly recommends the use of immunoglobulin G subclass 1 (IgG1)- or IgG crystallizable fragment (Fc) region-specific assays and allows the use of heavy-and-light-chain-(H+L) specific assays for detecting MOG-IgG. By contrast, the utility of MOG-IgG3-specific testing has not been systematically evaluated.

OBJECTIVE

To assess whether the use of MOG-IgG3-specific testing can improve the sensitivity of MOG-IgG testing.

METHODS

Re-testing of 22 patients with a definite diagnosis of MOG-EM/MOGAD and clearly positive MOG-IgG status initially but negative or equivocal results in H+L- or Fc-specific routine assays later in the disease course (i.e. patients with spontaneous or treatment-driven seroreversion).

RESULTS

In accordance with previous studies that had used MOG-IgG1-specific assays, IgG subclass-specific testing yielded a higher sensitivity than testing by non-subclass-specific assays. Using subclass-specific secondary antibodies, 26/27 supposedly seroreverted samples were still clearly positive for MOG-IgG, with MOG-IgG1 being the most frequently detected subclass (25/27 [93%] samples). However, also MOG-IgG3 was detected in 14/27 (52%) samples (from 12/22 [55%] patients). Most strikingly, MOG-IgG3 was the predominant subclass in 8/27 (30%) samples (from 7/22 [32%] patients), with no unequivocal MOG-IgG1 signal in 2 and only a very weak concomitant MOG-IgG1 signal in the other six samples. By contrast, no significant MOG-IgG3 reactivity was seen in 60 control samples (from 42 healthy individuals and 18 patients with MS). Of note, MOG-IgG3 was also detected in the only patient in our cohort previously diagnosed with MOG-IgA+/IgG- MOG-EM/MOGAD, a recently described new disease subvariant. MOG-IgA and MOG-IgM were negative in all other patients tested.

CONCLUSIONS

In some patients with MOG-EM/MOGAD, MOG-IgG is either exclusively or predominantly MOG-IgG3. Thus, the use of IgG1-specific assays might only partly overcome the current limitations of MOG-IgG testing and-just like H+L- and Fcγ-specific testing-might overlook some genuinely seropositive patients. This would have potentially significant consequences for the management of patients with MOG-EM/MOGAD. Given that IgG3 chiefly detects proteins and is a strong activator of complement and other effector mechanisms, MOG-IgG3 may be involved in the immunopathogenesis of MOG-EM/MOGAD. Studies on the frequency and dynamics as well as the clinical and therapeutic significance of MOG-IgG3 seropositivity are warranted.

Clinical and biochemical evaluation of rituximab as add on therapy in neuromyelitis optica spectrum disorders

OBJECTIVE

This study assesses the efficacy of rituximab in the treatment of neuromyelitis optica spectrum disorders (NMOSD).

METHODS

The study initially included 40 patients with NMOSD diagnosed, after excluding patients who did not meet the complete inclusion criteria. Patients in the conventional group received routine clinical treatment, while patients in the study group received additional treatment with rituximab on the basis of the conventional treatment. Baseline data and clinically relevant indicators were collected for all patients, and the efficacy was compared between the two groups.

RESULTS

Baseline data were comparable between the two groups (p > 0.05). The EDSS scores after clinical treatment in the study group were lower than those in the conventional group, and the difference in EDSS scores before and after treatment was higher than that in the conventional group (p < 0.05). The difference in visual acuity correction before and after treatment was not significant between the two groups (p > 0.05). Laboratory indicators in the study group after clinical treatment were superior to those in the conventional group (all p < 0.05). The recurrence rate after clinical treatment in the study group was significantly lower than that in the conventional group (p < 0.05). Adverse reactions after clinical treatment in the study group were less than those in the conventional group (p < 0.05).

CONCLUSION

This study found that rituximab demonstrated significant efficacy in the acute attacks and recurrence prevention of NMOSD, emphasizing its relatively good safety and tolerability. It highlights the potential of rituximab in treating NMOSD and provides valuable insights for future disease management.

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.

Treatment access and satisfaction on disease-modifying therapies of neuromyelitis optica spectrum disorder patients in China: a cross-sectional survey

Background

Neuromyelitis optica spectrum disorder (NMOSD) is a rare and debilitating disease that has become more widely recognized in China. Legislative measures have been implemented by the government to improve treatment access for rare diseases.

Objectives

To investigate the diagnostic journey, treatment status, treatment accessibility, and treatment satisfaction of the NMOSD patients on disease-modifying therapies (DMTs) in China.

Design

A patient online survey.

Methods

This cross-sectional online survey was conducted between November 2022 and January 2023. Patients over 18 years old and diagnosed with NMOSD were included. The questionnaire consisted of five sections covering demographics, diagnostic and treatment experiences, DMTs availability, cost and affordability, and treatment satisfaction using the Treatment Satisfaction Questionnaire for Medication (version II). Patient opinions and demands were also collected at the end of the survey.

Results

A total of 375 patients diagnosed with NMOSD were recruited, of which 321 patients used DMTs. It required 1.22 ± 3.22 years and 3.58 ± 4.24 hospital visits for a definitive diagnosis. One-third of the patients still needed to travel for over 2 h to access DMTs. The total treatment expenditure was estimated to be CNY 59,827.00 (USD 8315.95) a year. Drug expenses alone accounted for 52.22% of the average annual household income. The most common challenges perceived were the inability to afford treatment and a lack of effective options. No significant difference was found in treatment satisfaction among DMTs, except that rituximab scored lowest in convenience compared to other DMTs. Patients' age and travel time required to obtain medications were negatively associated with global treatment satisfaction.

Conclusion

In China, patients with NMOSD face challenges in obtaining proper treatment due to diagnostic difficulties, distant medication access, and high costs. Policies should prioritize improving disease education and alleviating financial burdens for the patients.

Predicting time to serologic diagnosis of AQP4+ NMOSD based on clinical factors and social determinants of health

BACKGROUND

Early serologic diagnosis and initiation of targeted therapy are associated with better outcomes in aquaporin-4 IgG positive (AQP4+) neuromyelitis optica spectrum disorder (NMOSD).

OBJECTIVE

To determine predictors of time to serologic diagnosis of AQP4+ NMOSD.

METHODS

In CANOPTICS, a multi-centre, Canadian cohort study of NMOSD, we retrospectively evaluated time from the first clinical attack to first positive AQP4-IgG serology. We used a multivariable negative binomial regression model to evaluate possible predictors of time to diagnosis.

RESULTS

We identified 129 participants with AQP4+ NMOSD from 7 centres. Diagnostic delay of >1 month was observed in 82 (63.6 %). Asian compared to European (White) ethnicity (IRR:0.40, 95 % CI:0.21-0.78), female sex (IRR:0.56, 95 % CI:0.32-0.99), later calendar year (IRR:0.84, 95 % CI:0.81-0.86), and hospitalization for the first attack (IRR:0.35, 95 % CI:0.20-0.62) were associated with shorter times to serologic diagnosis. We did not observe any overall effect of Afro-Caribbean ethnicity, but in exploratory analyses, Afro-Caribbean individuals with low income had longer times to diagnosis.

CONCLUSION

More than 60 % of patients with NMOSD experienced delays to AQP4-IgG serologic diagnosis in this cohort. Given evidence of more adverse long-term outcomes in Afro-Caribbean individuals with NMOSD, intersectional effects of ethnicity and social determinants of health merit further study.

Therapeutic inertia in the management of neuromyelitis optica spectrum disorder

Introduction and objective

Limited information is available on how neurologists make therapeutic decisions in neuromyelitis optica spectrum disorder (NMOSD), especially when new treatments with different mechanisms of action, administration, and safety profile are being approved. Decision-making can be complex under this uncertainty and may lead to therapeutic inertia (TI), which refers to lack of treatment initiation or intensification when therapeutic goals are not met. The study aim was to assess neurologists' TI in NMOSD.

Methods

An online, cross-sectional study was conducted in collaboration with the Spanish Society of Neurology. Neurologists answered a survey composed of demographic characteristics, professional background, and behavioral traits. TI was defined as the lack of initiation or intensification with high-efficacy treatments when there is evidence of disease activity and was assessed through five NMOSD aquaporin-4 positive (AQP4+) simulated case scenarios. A multivariate logistic regression analysis was used to determine the association between neurologists' characteristics and TI.

Results

A total of 78 neurologists were included (median interquartile range [IQR] age: 36.0 [29.0-46.0] years, 55.1% male, median [IQR] experience managing demyelinating conditions was 5.2 [3.0-11.1] years). The majority of participants were general neurologists (59.0%) attending a median (IQR) of 5.0 NMOSD patients (3.0-12.0) annually. Thirty participants (38.5%) were classified as having TI. Working in a low complexity hospital and giving high importance to patient's tolerability/safety when choosing a treatment were predictors of TI.

Conclusion

TI is a common phenomenon among neurologists managing NMOSD AQP4+. Identifying TI and implementing specific intervention strategies may be critical to improving therapeutic decisions and patient care.

Case report: Tolosa-Hunt syndrome-expanding the neuromyelitis optica spectrum disorder phenotype?

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune astrocytopathy caused by the autoantibody of aquaporin-4 (AQP4). Herein, we report a case of Tolosa-Hunt syndrome presenting with abducens palsy and AQP4 antibodies. This was a rare case of AQP4-immunoglobulin G seropositivity in a patient with Tolosa-Hunt syndrome. Our findings may expand the clinical phenotype of NMOSD and indicate that clinicians should consider testing for AQP4 antibodies in patients with Tolosa-Hunt syndrome.

Clinical and imaging features of patients with late-onset myelin oligodendrocyte glycoprotein antibody-associated disease

BACKGROUND

There is an age-dependent change in the clinical phenotype of Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). However, the clinical features of late-onset MOGAD have not been well described.

METHODS

Clinical data of 110 MOGAD patients, including 21 late-onset patients with onset age greater than or equal to 50 years old were retrospectively analyzed.

RESULTS

Compared to pediatric- and younger adult-onset ones, late-onset MOGAD patients experienced milder disease onset (p < 0.001), more monophasic course (p < 0.001), fewer relapses (p = 0.007), less cerebrospinal fluid leukocytosis (p = 0.021), less longitudinally extensive transverse myelitis (onset p = 0.026, whole course p = 0.028), fewer lesions in basal ganglia (whole course p = 0.012), thalamus (whole course p = 0.040) and cerebellum (whole course p = 0.028). However, they had more cerebral symptoms (p = 0.021 onset and whole course), more lesions in white matter (onset p = 0.005, whole course p < 0.001) and periventricular area (onset p = 0.026), along with longer and delayed therapeutic intervention (p < 0.001). The main differences in clinical characteristics between late-onset patients with and without these brain involvements might be comorbidities.

CONCLUSIONS

Late-onset MOGAD are more likely to experience delayed diagnosis. Brain involvement may be modulated by comorbidities of the elderly, which alter the clinical manifestations of late-onset MOGAD.

Prevalence of neuromyelitis optica spectrum disorder in the United States

BACKGROUND

Neuromyelitis optic spectrum disorder (NMOSD) is a rare demyelinating, autoimmune disease and the burden in United States is not well characterized.

OBJECTIVE

The objective of this study was to determine the 2022 US prevalence of NMOSD.

METHODS

We constructed a cross-sectional study using aggregated electronic health record data for 25.7 million patients who had a 2022 clinical encounter. The data originated from the TriNetX US Collaborative Network of 55 healthcare organizations that span all 50 states. NMOSD prevalence was determined by querying for age-interval, sex, and race combinations, with direct standardization to the 2022 US Census data.

RESULTS

There were 1772 NMOSD patients among 25,743,039 patients for a prevalence of 6.88/100,000. Prevalence was the highest in Blacks (12.99/100,000) who represented 27.7% of NMOSD patients, then Asians (9.41/100,000and Whites (5.58/100,000). Among females, the prevalence of NMOSD was 9.48/100,000, and Black and Asian females had a 2.65- and 1.94-times higher prevalence than White females. In males, the prevalence of NMOSD was 3.52/100,000 and it did not differ by race. We observed a 3/5:1 female-to-male ratio in NMOSD. The age- and sex-adjusted 2022 estimate of persons with NMOSD in the United States was 15,413 females and 6233 males.

CONCLUSION

We estimate that there were near 22,000 Americans living with NMOSD in 2022.

Relapses and Serious Infections in Patients with Neuromyelitis Optica Spectrum Disorder Treated with Rituximab: A Swedish Single-Center Study

Neuromyelitis optica spectrum disorder (NMOSD) is a rare immune-mediated relapsing-remitting disease of the central nervous system. The usage of rituximab, as relapse-preventive therapy, in NMOSD is common. We performed a single-center retrospective cohort study to assess the risk of relapses and severe infectious events (SIEs) in rituximab-treated NMOSD patients. This study included 24 aquaporin-4 IgG+ (AQP4+), 8 myelin-oligodendrocyte-protein IgG+ (MOG+), and 10 double-seronegative NMOSD patients. Relapses were observed in 50% of all patients during a mean treatment time of 4.0 (range: 0.5-8.25) years. The incidence risk ratio (IRR) of relapse was three times higher in MOG+ compared to AQP4+ patients (IRR: 3.0, 95% confidence interval (CI); 1.2-7.7). SIEs occurred in 40% of all patients during follow-up. AQP4+ patients conferred an increased risk of SIEs compared to MOG+ patients (IRR; 5.3, 95% CI; 1.2-24.3). Incomplete CD19+ B-lymphocyte suppression was not correlated with relapse risk (hazard ratio; 1.9, 95% CI; 0.7-5.2), and there was no correlation between IgG-levels and SIE risk (odds ratio; 2.0, 95% CI; 0.8-4.8). In conclusion, considerable risks of both relapses and SIEs were observed in NMOSD patients exposed to rituximab, which underlines the need for close clinical vigilance of disease activity and infections during treatment.

Eculizumab for a catastrophic relapse in NMOSD: case report

Neuromyelitis optica spectrum disorders (NMOSD) are a group of inflammatory disorders of central nervous system characterized by immune-mediated demyelination and axonal damage, predominantly affecting spinal cord and optic nerves. This case report describes a 47-year-old woman with an aggressive form of seropositive NMOSD who had previously been treated with corticosteroids, plasma exchange, and cyclophosphamide. She experienced a life-threatening relapse that did not respond to conventional treatment, but ultimately showed a positive response to eculizumab. Furthermore, we describe the role of sNfL.

Update on the diagnosis and treatment of neuromyelitis optica spectrum disorders (NMOSD) - revised recommendations of the Neuromyelitis Optica Study Group (NEMOS). Part II: Attack therapy and long-term management

This manuscript presents practical recommendations for managing acute attacks and implementing preventive immunotherapies for neuromyelitis optica spectrum disorders (NMOSD), a rare autoimmune disease that causes severe inflammation in the central nervous system (CNS), primarily affecting the optic nerves, spinal cord, and brainstem. The pillars of NMOSD therapy are attack treatment and attack prevention to minimize the accrual of neurological disability. Aquaporin-4 immunoglobulin G antibodies (AQP4-IgG) are a diagnostic marker of the disease and play a significant role in its pathogenicity. Recent advances in understanding NMOSD have led to the development of new therapies and the completion of randomized controlled trials. Four preventive immunotherapies have now been approved for AQP4-IgG-positive NMOSD in many regions of the world: eculizumab, ravulizumab - most recently-, inebilizumab, and satralizumab. These new drugs may potentially substitute rituximab and classical immunosuppressive therapies, which were as yet the mainstay of treatment for both, AQP4-IgG-positive and -negative NMOSD. Here, the Neuromyelitis Optica Study Group (NEMOS) provides an overview of the current state of knowledge on NMOSD treatments and offers statements and practical recommendations on the therapy management and use of all available immunotherapies for this disease. Unmet needs and AQP4-IgG-negative NMOSD are also discussed. The recommendations were developed using a Delphi-based consensus method among the core author group and at expert discussions at NEMOS meetings.

A comprehensive review of the advances in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare relapsing neuroinflammatory autoimmune astrocytopathy, with a predilection for the optic nerves and spinal cord. Most cases are characterised by aquaporin-4-antibody positivity and have a relapsing disease course, which is associated with accrual of disability. Although the prognosis in NMOSD has improved markedly over the past few years owing to advances in diagnosis and therapeutics, it remains a severe disease. In this article, we review the evolution of our understanding of NMOSD, its pathogenesis, clinical features, disease course, treatment options and associated symptoms. We also address the gaps in knowledge and areas for future research focus.

Neuromyelitis Optica: Pathogenesis Overlap with Other Autoimmune Diseases

PURPOSE OF REVIEW

Neuromyelitis optica (NMO) is an auto-immune disease essentially depicted by optic neuritis and transverse myelitis. Per se, NMO was initially believed to be a sub-type of multiple sclerosis with typical demyelinating cerebral lesions and optic nerve inflammation. More recently, corroborating lignes of evidence have strengthened the concept of the spectrum of diseases associated with NMO and more specifically with the role of anti-aquaporin-4 antibodies in the pathogenesis of disease.

RECENT FINDINGS

In this article, we review the recent pathogenic findings in NMO and more interestingly the newly discovered role of anti-aquaporin-4 antibodies as key players in triggering cerebral lesions. The concept of spectrum of diseases associated with NMO is also discussed. These recent findings have paved in the further understanding of the pathogenesis underlying NMO and new treatments are currently being developed targeting anti-aquaporin-4 antibodies.

Potential Role of Antibodies against Aquaporin-1 in Patients with Central Nervous System Demyelination

Aquaporins (AQPs; AQP0-AQP12) are water channels expressed in many and diverse cell types, participating in various functions of cells, tissues, and systems, including the central nervous system (CNS). AQP dysfunction and autoimmunity to AQPs are implicated in several diseases. The best-known example of autoimmunity against AQPs concerns the antibodies to AQP4 which are involved in the pathogenesis of neuromyelitis optica spectrum disorder (NMOSD), an autoimmune astrocytopathy, causing also CNS demyelination. The present review focuses on the discovery and the potential role of antibodies against AQP1 in the CNS, and their potential involvement in the pathophysiology of NMOSD. We describe (a) the several techniques developed for the detection of the AQP1-antibodies, with emphasis on methods that specifically identify antibodies targeting the extracellular domain of AQP1, i.e., those of potential pathogenic role, and (b) the available evidence supporting the pathogenic relevance of AQP1-antibodies in the NMOSD phenotype.

Blood-Brain Barrier Breakdown in Neuroinflammation: Current In Vitro Models

The blood-brain barrier, which is formed by tightly interconnected microvascular endothelial cells, separates the brain from the peripheral circulation. Together with other central nervous system-resident cell types, including pericytes and astrocytes, the blood-brain barrier forms the neurovascular unit. Upon neuroinflammation, this barrier becomes leaky, allowing molecules and cells to enter the brain and to potentially harm the tissue of the central nervous system. Despite the significance of animal models in research, they may not always adequately reflect human pathophysiology. Therefore, human models are needed. This review will provide an overview of the blood-brain barrier in terms of both health and disease. It will describe all key elements of the in vitro models and will explore how different compositions can be utilized to effectively model a variety of neuroinflammatory conditions. Furthermore, it will explore the existing types of models that are used in basic research to study the respective pathologies thus far.

Neuromyelitis optica spectrum disorder with AQP4-IgG presenting as area postrema syndrome and progressing to myelitis: A rare case report

Key Clinical Message

Neuromyelitis optica spectrum disorders can less commonly present with area postrema syndrome progressing to myelitis. Management involves intravenous glucocorticoids, plasma exchange, and preventive immunotherapy.

Abstract

Neuromyelitis optica spectrum disorders can less commonly present with area postrema syndrome progressing to myelitis. The majority of patients have positive AQP4-Ab. Diagnosis is based on clinical and imaging findings. These patients can be treated with intravenous glucocorticoids, plasma exchange, and preventive immunotherapy.