Neuromyelitis optica spectrum disorders: An update

Sex hormones and neuromyelitis optica spectrum disorder: a bidirectional Mendelian randomization study

BACKGROUND

Females are considered to have an increased susceptibility to neuromyelitis optica spectrum disorder (NMOSD) than males, especially aquaporin-4 (AQP4) antibody positive NMOSD, indicating that sex hormones may be involved in the NMOSD pathogenesis. However, the causality between sex hormones and NMOSD still remains unclear.

METHODS

Based on the genome-wide association study (GWAS) data of three sex hormones (estradiol (E2), progesterone (PROG) and bioavailable testosterone (BAT)), sex hormone-binding globulin (SHBG), age of menarche, age of menopause, and NMOSD (total, AQP4 + and AQP4 -), we performed a two-sample bidirectional Mendelian randomization (MR) study. Sex-stratified GWAS data of E2, PROG, BAT, and SHBG was obtained for gender-specific MR analysis. Causal inferences were based on the inverse variance weighted method, MR-Egger regression, and weighted median method. The reverse MR analysis was also performed to assess the impact of NMOSD on hormone levels.

RESULTS

PROG in females had aggravative effects on NMOSD (P < 0.001), especially AQP4 - NMOSD (P < 0.001). In the reverse MR analysis, total NMOSD was found to decrease the level of BAT (P < 0.001) and increase the level of SHBG (P = 0.001) in females.

CONCLUSION

Findings of this MR analysis revealed mutual causal associations between sex hormones and NMOSD, which provided novel perspectives about the gender-related pathogenesis of NMOSD.

Discrepancy in clinical and laboratory profiles of NMOSD patients between AQP4 antibody positive and negative: can NMOSD be diagnosed without AQP4 antibody?

AQP4-IgG has been considered as the pathogenic factor leading to NMOSD. However, about 20-30% of patients lack AQP4-IgG. So far, all therapeutic medicines are ineffective for NMOSD patients without AQP4 IgG. Thus AQP4-IgG is the pathogenic factor of NMOSD has been suspected and challenged. In addition, lack of efficacy of immunotherapy in NMOSD without AQP4 IgG has been a serious problem in the neurology. Identifying the clinical and laboratory characteristics and diversities between NMOSD patients with and without AQP4-IgG can be helpful to further explore the pathogenesis of NMOSD and guide clinical treatment. This is a single-centre retrospective study in The First Hospital of Jilin University, China including 92 patients diagnosed as NMOSD from January 2013 to January 2015. The characteristics of clinic, blood, cerebrospinal fluid (CSF), and image between AQP4-IgG negative (AQP4-IgG-) and AQP4-IgG positive (AQP4-IgG+) NMOSDs were compared. Our results showed that in the AQP4-IgG+ group, the ratio of women to men was 5.55, while in AQP4-IgG- group was 1.54 (P = 0.0092). In the AQP4-IgG+ patients, the expanded disability status scale (EDSS) was from 0 to 8.5, with an average of 5.550 ± 0.25, and the AQP4-IgG- patients had the EDSS score from 0 to 9, with an average of 4.032 ± 0.36 (P = 0.0006), which mainly affected movement system (P < 0.05) and superficial sensory impairment (P < 0.05). In the AQP4-IgG+ group, the blood brain barrier (BBB) permeability (P = 0.0210) and myelin basic protein (MBP) were increased (P = 0.0310) when compared to AQP4-IgG- group. Higher level IL-17 was seen in AQP4-IgG+ group than AQP4-IgG- group (P= 0.0066). Our results demonstrated that the NMOSD with AQP4-IgG more likely occurred in women and presented more severe clinical symptoms as well as significant BBB damage and increased MBP and IL-17 in CSF and blood, respectively compared with NMOSD without AQP4-IgG group. The differences in clinical and laboratory profiles between NMOSD with and without AQP4-IgG indicate the heterogeneity of NMOSD, in which AQP4-IgG may not be the only pathogenic molecule. It is necessary to find more pathogenic factors and to explore the new pathogenesis of NMOSD and therapeutic methods in the future.

Progress in treatment of neuromyelitis optica spectrum disorders (NMOSD): Novel insights into therapeutic possibilities in NMOSD

Neuromyelitis optica spectrum disorder (NMOSD) is a rare autoimmune inflammatory demyelinating disorder of the central nervous system (CNS), which is a severely disabling disorder leading to devastating sequelae or even death. Repeated acute attacks and the presence of aquaporin-4 immunoglobulin G (AQP4-IgG) antibody are the typical characteristics of NMOSD. Recently, the phase III trials of the newly developed biologicals therapies have shown their effectiveness and good tolerance to a certain extent when compared with the traditional therapy with the first- and second-line drugs. However, there is still a lack of large sample, double-blind, randomized, clinical studies to confirm their efficacy, safety, and tolerability. Especially, these drugs have no clear effect on NMOSD patients without AQP4-IgG and refractory patients. Therefore, it is of strong demand to further conduct large sample, double-blind, randomized, clinical trials, and novel therapeutic possibilities in NMOSD are discussed briefly here.

SARS-CoV-2 triggering autoimmune diseases

Autoimmunity, hyperstimulation of the immune system, can be caused by a variety of reasons. Viruses are thought to be important environmental elements that contribute to the development of autoimmune antibodies. It seems that viruses cause autoimmunity with mechanisms such as molecular mimicry, bystander activation of T cells, transient immunosuppression, and inflammation, which has also been seen in post-Covid-19 autoimmunity. Infection of respiratory epithelium by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dysregulates the immune response, triggers both innate and acquired immunity that led to the immune system's hyperactivation, excessive cytokine secretion known as “cytokine storm,” and finally acute respiratory distress syndrome (ARDS) associated with high mortality. Any factor in the body that triggers chronic inflammation can contribute to autoimmune disease, which has been documented during the Covid-19 pandemic. It has been observed that some patients produce autoantibody and autoreactive CD4⁺ and CD8⁺ T cells, leading to the loss of self-tolerance. However, there is a scarcity of evidence defining the precise molecular interaction between the virus and the immune system to elicit autoreactivity. Here, we present a review of the relevant immunological findings in Covid-19 and the current reports of autoimmune disease associated with the disease.

Approach to optic neuritis: An update

Over the past few years, there has been remarkable development in the area of optic neuritis. The discovery of new antibodies has improved our understanding of the pathology of the disease. Antiaquaporin4 antibodies and antimyelin oligodendrocytes antibodies are now considered as distinct entities of optic neuritis with their specific clinical presentation, neuroimaging characteristics, treatment options, and course of the disease. Similarly, there has been a substantial change in the treatment of optic neuritis which was earlier limited to steroids and interferons. The development of new immunosuppressant drugs and monoclonal antibodies has reduced the relapses and improved the prognosis of optic neuritis as well as an associated systemic disease. This review article tends to provide an update on the approach and management of optic neuritis.

Comparisons of clinical phenotype, radiological and laboratory features, and therapy of neuromyelitis optica spectrum disorder by regions: update and challenges

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory demyelinating disease of the central nervous system (CNS) associated with autoantibody (ab) to aquaporin-4 (AQP4). There is obvious variation between regions and countries in the epidemiology, clinical features and management in NMOSD. Based on published population-based observation and cohort studies, the different clinical pattern of NMOSD has been seen in several geographical regions and some of these patients with NMOSD-like features do not fully meet the current diagnostic criteria, which is needed to consider the value of recently revised diagnostic criteria. At present, all treatments applied in NMOSD have made great progress, however, these treatments failed in AQP4 ab negative and refractory patients. Therefore, it is necessary to turn into an innovative idea and to open a new era of NMOSD treatment to develop novel and diverse targets and effective therapeutic drugs in NMOSD and to conduct the trails in large clinical samples and case-control studies to confirm their therapeutic effects on NMOSD in the future, which still remain a challenge.

Is Fertility Affected in Women of Childbearing Age with Multiple Sclerosis or Neuromyelitis Optica Spectrum Disorder?

Multiple sclerosis (MS) is a chronic immune-mediated demyelinating disease of the central nervous system (CNS), which is more prevalent among women of childbearing age. Neuromyelitis optica spectrum disorder (NMOSD) is a severe autoimmune disease of the CNS with similar prevalence features to MS and has recently been considered a different entity from MS. Measuring ovarian reserve is one way of evaluating fertility. Anti-Müllerian hormone (AMH) is a peptide hormone produced by ovarian granulosa cells of early follicles and is considered to be a marker for ovarian reserve. With MS and NMOSD predominance in young women, the present study aimed to address the possibility of these diseases affecting fertility by measuring AMH levels in MS and NMOSD patients and comparing it with healthy controls. The present study included 23 relapsing-remitting MS (RRMS) patients, 23 seronegative NMOSD patients, and 23 healthy age-matched controls between 18 and 45 years of age. Serum samples of the three groups were collected, and the AMH levels were measured with AMH Gen II Enzyme-Linked Immunosorbent Assay, Beckman Coulter kit. In the present study, the AMH levels did not differ significantly between the groups (p = 0.996). The mean AMH in the RRMS group was 3.59 ± 0.55 ng/ml compared with the mean of 3.60 ± 0.50 ng/ml in healthy controls. The mean AMH levels in the NMOSD group were 3.66 ± 0.61 ng/ml. Lower levels of AMH were found to be negatively associated with annualized relapse rate (in both groups of patients) and MS severity score. However, the difference was not significant. In NMOSD patients, the serum levels of AMH were negatively associated with disease duration (r = - 0.42, p = 0.023). There had been a significant negative correlation between mean AMH serum levels with Expanded Disability Status Scale (EDSS) at the time of diagnosis and at the time of study in the NMOSD group (r = - 0.402, p = 0.03 and r = - 0.457, p = 0.014, respectively). There was not a significant difference in mean serum AMH levels between RRMS and NMOSD patients compared with that of healthy controls. Further studies with larger sample sizes should be conducted, which take more variables affecting fertility in women with either RRMS or NMOSD into account to put an end to the controversial issue of fertility in this area.

Acute anosmia in neuromyelitis optica spectrum disorder

The cardinal features of neuromyelitis optica spectrum disorder (NMOSD) are optic neuritis, longitudinal extensive transverse myelitis and area postrema syndrome. Olfactory dysfunction is not listed as a feature in the NMOSD diagnostic criteria. Here, we present an aquaporin-4 antibody positive patient who, in addition to classical features of NMOSD, developed acute anosmia with magnetic resonance imaging (MRI) evidence of olfactory bulb abnormalities. While the association of anosmia and NMOSD has been rarely noted previously, to our knowledge, no prior cases have found this to be one of the presenting features of a relapse nor have they identified acute radiological correlates.

Neuro-Behcet's disease: An update on diagnosis, differential diagnoses, and treatment

Neuro-Behcet's disease (NBD) is defined as a combination of neurologic symptoms and/or signs in a patient with Behcet's disease (BD). Relevant syndromes include brainstem syndrome, multiple-sclerosis like presentations, movement disorders, meningoencephalitic syndrome, myelopathic syndrome, cerebral venous sinus thrombosis (CVST), and intracranial hypertension. Central nervous involvement falls into parenchymal and non-parenchymal subtypes. The parenchymal type is more prevalent and presents as brainstem, hemispheric, spinal, and meningoencephalitic manifestations. Non-parenchymal type includes CVST and arterial involvement. Perivascular infiltration of polymorphonuclear and mononuclear cells is seen in most histo-pathologic reports. In parenchymal NBD, cerebrospinal fluid (CSF) generally exhibits pleocytosis, increased protein and normal glucose. In NBD and CVST, CSF pressure is increased but content is usually normal. The typical acute NBD lesions in brain magnetic resonance imaging (MRI) are mesodiencephalic lesions. The pattern of extension from thalamus to midbrain provides a cascade sign. Brain MRI in chronic NBD usually shows brain or brainstem atrophy and/or black holes. The spinal MRI in the acute or subacute myelopathies reveals noncontiguous multifocal lesions mostly in cervical and thoracic lesions. In chronic patients, cord atrophy can also be seen. Brain MRI (particularly susceptibility-weighted images), MR venography (MRV) and computerized tomographic venography (CTV) can be used to diagnose CVST. Parenchymal NBD attacks can be treated with glucocorticoids alone or in combination with azathioprine. For patients with relapsing-remitting or progressive courses, shifting to more potent immunosuppressive drugs such as mycophenolate, methotrexate, cyclophosphamide, or targeted therapy is warranted. For NBD and CVST, immunosuppressive drugs with or without anticoagulation are suggested.

Longitudinally Extensive Transverse Myelitis Due to Toxoplasma: An Autopsy Study

Toxoplasma is an obligate intracellular parasite that remains asymptomatic in humans but, at times, can cause devastating disease. Here, we describe an autopsy study of a young immunocompetent gentleman with no comorbidities whose presentation was acute transverse myelitis. Magnetic resonance imaging spine showed longitudinally extensive spinal cord lesion (LESCL) that mimicked neuromyelitis optica with normal brain imaging at presentation. Investigations showed albuminocytological dissociation which prompted a course of parenteral steroid. However, the lesion relentlessly progressed to involve the brain stem and cerebrum leading to toxoplasmic encephalitis that terminated fatally. This report highlights that toxoplasma can present as LESCL and needs to be considered in the differential diagnosis of atypical myelitis.

Diagnosis and management of Neuromyelitis Optica Spectrum Disorder (NMOSD) in Iran: A consensus guideline and recommendations

Neuromyelitis Optica Spectrum Disorder (NMOSD) is a relapsing neuro inflammatory disease of the central nervous system that typically presents with optic neuritis or myelitis and may cause severe disability. The diagnostic criteria have been updated and several immunosuppressive agents have been demonstrated to prevent acute exacerbations. As the disease rarely develops in a progressive course, management of acute attacks and proper prevention of exacerbations may change the long term out-come and prevent future disability. Consensus recommendations and guidelines will help the physicians to improve their practice and unify the treatment approaches in different communities. In order to develop a national consensus and recommendations for the diagnosis and management of NMOSD in Iran, a group of neurologists with long term experience in management of NMOSD were gathered to develop this consensus based on available national and international data. The primary draft was prepared and discussed to suggest the most appropriate treatment for these patients. We propose strategies for early diagnosis and treatment for prevention of relapses and minimizing consequences of attacks as a primary therapeutic goal. Attacks are currently treated with intravenous corticosteroids and, in refractory cases, with plasma exchange. All participants agreed on preventive treatment with currently available immunosuppressive agents such as azothioprin, rituximab and mycofenolate mofetil based on previous positive data in NMOSD in order to reduce attack frequency. The current consensus reviews the previous data and provides the clinicians with practical recommendations and advices for the diagnosis and management of NMOSD based on scientific data and clinical experience.

Anti-myelin oligodendrocyte glycoprotein antibodies: Magnetic resonance imaging findings in a case series and a literature review

Myelin oligodendrocyte glycoprotein is a protein exclusively expressed on the surface of oligodendrocytes and myelin in the central nervous system. Antibodies against myelin oligodendrocyte glycoprotein were initially detected in children with demyelinating syndromes, and more recently reported in a broad spectrum of central nervous system demyelinating diseases in adults, including neuromyelitis optica spectrum disorders and bilateral optic neuritis. Patients with myelin oligodendrocyte glycoprotein antibody-associated demyelination appear to have unique clinical and radiological features. To the best of our knowledge a series of Italian patients with optic neuritis and positivity to myelin oligodendrocyte glycoprotein antibodies has not yet been reported and the paper on myelin oligodendrocyte glycoprotein antibodies are more focused on clinical features, diagnosis and outcome than on the radiological appearance, so we want to retrospectively report magnetic resonance imaging features of a group of eight patients, who came to our Ophthalmologic Emergency Department for optic neuritis and were found seropositive for myelin oligodendrocyte glycoprotein antibodies, comparing our data with the findings described in the literature.

A 66-Year-Old Woman with a Progressive, Longitudinally Extensive, Tract Specific, Myelopathy

A 66-year-old woman presented with progressive lancinating pain and sensory deficits attributable to a myelopathy of unclear etiology. Spinal cord magnetic resonance imaging showed a longitudinally extensive T2-hyperintense lesion of the dorsal columns. Comprehensive serum, urine, and cerebrospinal fluid analyses failed to identify an etiology. Empiric intravenous methylprednisolone and intravenous immunoglobulin were of no benefit and serial screens for an occult malignancy were negative. She developed dysesthesias and allodynia affecting her entire body and lost the use of her arms and legs due to severe sensory ataxia that was steadily progressive from onset. She opted against additional aggressive medical management of her condition and passed away on hospice eleven months after symptom onset. Autopsy revealed findings most consistent with polyphasic spinal cord ischemia affecting the dorsal and lateral white matter tracts and, to a lesser extent, adjacent gray matter. The underlying etiology for the progressive vasculopathy remains unknown. Spinal cord ischemia affecting the posterior spinal cord is rare and to our knowledge this case represents the only instance of a progressive spinal cord tractopathy attributable to chronic spinal cord ischemia.

Research into the Physiology of Cerebrospinal Fluid Reaches a New Horizon: Intimate Exchange between Cerebrospinal Fluid and Interstitial Fluid May Contribute to Maintenance of Homeostasis in the Central Nervous System

Cerebrospinal fluid (CSF) plays an essential role in maintaining the homeostasis of the central nervous system. The functions of CSF include: (1) buoyancy of the brain, spinal cord, and nerves; (2) volume adjustment in the cranial cavity; (3) nutrient transport; (4) protein or peptide transport; (5) brain volume regulation through osmoregulation; (6) buffering effect against external forces; (7) signal transduction; (8) drug transport; (9) immune system control; (10) elimination of metabolites and unnecessary substances; and finally (11) cooling of heat generated by neural activity. For CSF to fully mediate these functions, fluid-like movement in the ventricles and subarachnoid space is necessary. Furthermore, the relationship between the behaviors of CSF and interstitial fluid in the brain and spinal cord is important. In this review, we will present classical studies on CSF circulation from its discovery over 2,000 years ago, and will subsequently introduce functions that were recently discovered such as CSF production and absorption, water molecule movement in the interstitial space, exchange between interstitial fluid and CSF, and drainage of CSF and interstitial fluid into both the venous and the lymphatic systems. Finally, we will summarize future challenges in research. This review includes articles published up to February 2016.