MOG antibody-positive, benign, unilateral, cerebral cortical encephalitis with epilepsy

Objective:

To describe the features of adult patients with benign, unilateral cerebral cortical encephalitis positive for the myelin oligodendrocyte glycoprotein (MOG) antibody.

Methods:

In this retrospective, cross-sectional study, after we encountered an index case of MOG antibody–positive unilateral cortical encephalitis with epileptic seizure, we tested for MOG antibody using our in-house, cell-based assay in a cohort of 24 consecutive adult patients with steroid-responsive encephalitis of unknown etiology seen at Tohoku University Hospital (2008–2014). We then analyzed the findings in MOG antibody–positive cases.

Results:

Three more patients, as well as the index case, were MOG antibody–positive, and all were adult men (median age 37 years, range 23–39 years). The main symptom was generalized epileptic seizure with or without abnormal behavior or consciousness disturbance. Two patients also developed unilateral benign optic neuritis (before or after seizure). In all patients, brain MRI demonstrated unilateral cerebral cortical fluid-attenuated inversion recovery hyperintense lesions, which were swollen and corresponded to hyperperfusion on SPECT. CSF studies showed moderate mononuclear pleocytosis with some polymorphonuclear cells and mildly elevated total protein levels, but myelin basic protein was not elevated. A screening of encephalitis-associated autoantibodies, including aquaporin-4, glutamate receptor, and voltage-gated potassium channel antibodies, was negative. All patients received antiepilepsy drugs and fully recovered after high-dose methylprednisolone, and the unilateral cortical MRI lesions subsequently disappeared. No patient experienced relapse.

Conclusions:

These MOG antibody–positive cases represent unique benign unilateral cortical encephalitis with epileptic seizure. The pathology may be autoimmune, although the findings differ from MOG antibody–associated demyelination and Rasmussen and other known immune-mediated encephalitides.

Hypoxia-like tissue injury and glial response contribute to Balo concentric lesion development

Objective:

To clarify the pathogenic factors and mechanisms underlying the development of concentric demyelinating lesions in Balo disease.

Methods:

We conducted serial clinical, MRI, and histopathologic assessments of concentric lesion formation in a case of relapsing Balo disease.

Results:

The patient experienced 2 attacks caused by left parietal and left frontal lesions in 5 years. In MRI findings from both episodes of expanding lesions, there were diffusion-restricted rings that antedated the appearance of gadolinium enhancement; subsequently, typical concentric T2 lesions appeared concurrently with the disappearance of this enhancement. Histopathologic examinations of biopsied brain tissues revealed definite concentric demyelinating layers typical of Balo disease with massive macrophage infiltration but preserved axons. Numerous hypertrophic astrocytes were observed beyond the edges of and within the demyelinating layers. The expression of hypoxia-inducible factor-1α, a protein related to hypoxia-induced tissue preconditioning that contributes to survival and protection against further hypoxia-like injury, was upregulated primarily in glial cells located beyond the edge of the demyelinating layers but was also elevated in hypertrophic astrocytes on the inner sides of resected lesions and in oligodendrocytes in nondemyelinating layers. In addition, these astrocytes expressed CC motif chemokine 2 and/or interleukin-1β, which are inducible by hypoxia-inducible factor-1α and potentially promote demyelination.

Conclusions:

Our study suggests that a unique interplay between hypoxia-induced tissue preconditioning and proinflammatory cytokines derived from glial cells may contribute to the development of concentric demyelinating lesions in Balo disease.

Complement-dependent and -independent aquaporin 4-antibody-mediated cytotoxicity in human astrocytes: Pathogenetic implications in neuromyelitis optica

Background

Neuromyelitis optica (NMO) is an inflammatory disease caused by the aquaporin (AQP)-4-antibody. Pathological studies on NMO have revealed extensive astrocytic damage, as evidenced by the loss of AQP4 and glial fibrillary acidic protein (GFAP), specifically in perivascular regions with immunoglobulin and complement depositions, although other pathological patterns, such as a loss of AQP4 without astrocyte destruction and clasmatodendrosis, have also been observed. Previous studies have shown that complement-dependent antibody-mediated astrocyte lysis is likely a major pathomechanism in NMO. However, there are also data to suggest antibody-mediated astrocyte dysfunction in the absence of complement. Thus, the importance of complement inhibitory proteins in complement-dependent AQP4-antibody-mediated astrocyte lysis in NMO is unclear. In most of the previous studies, the complement and target cells (astrocytes or AQP4-transfected cells) were derived from different species; however, the complement inhibitory proteins that are expressed on the cell surface cannot protect themselves against complement-dependent cytolysis unless the complements and complement inhibitory proteins are from the same species. To resolve these issues, we studied human astrocytes in primary culture treated with AQP4-antibody in the presence or absence of human complement and examined the effect of complement inhibitory proteins using small interfering RNA (siRNA).

Methods

Purified IgG (10 mg/mL) was obtained from 5 patients with AQP4-antibody-positive NMO, 3 patients with multiple sclerosis (MS), and 3 healthy controls. Confluent human astrocytes transfected with Venus-M1-AQP4-cDNA were incubated with IgG (5% volume). After washing, we cultured the cells with human complements with or without heat inactivation. We observed time-lapse morphological and immunohistochemical changes using a fluorescence microscope. We also evaluated cytotoxicity using a propidium iodide (PI) kit and the lactate dehydrogenase (LDH) assay.

Result

AQP4-antibody alone caused clustering and degradation followed by endocytosis of membraneous AQP4, thereby resulting in decreased cellular adherence and the shrinkage of astrocytic processes. However, these changes were partially reversed by the removal of IgG in culture. In contrast, following the application of AQP4-antibody and non-heated human complements, the cell bodies and nuclei started to swell. At 3 h, most of the astrocytes had lost mobility and adherence and were eventually destroyed or had swollen and were then destroyed. In addition, the remaining adherent cells were mostly PI-positive, indicating necrosis. Astrocyte lysis caused by rabbit complement occurred much faster than did cell lysis with human complement. However, the cell lysis was significantly enhanced by the transfection of astrocytes with siRNA against human CD55 and CD59, which are major complement inhibitory proteins on the astrocyte membrane. AQP4-antibody-negative IgG in MS or control did not induce such changes.

Conclusion

Taken together, these findings suggest that both complement-dependent and complement-independent AQP4-antibody-mediated astrocytopathies may operate in NMO, potentially contributing to diverse pathological patterns. Our results also suggest that the effect of complement inhibitory proteins should be considered when evaluating AQP4-antibody-mediated cytotoxicity in AQP4-expressing cells.

Negative ion production and beam extraction processes in a large ion source (invited)

Recent research results on negative-ion-rich plasmas in a large negative ion source have been reviewed. Spatial density and flow distributions of negative hydrogen ions (H(-)) and positive hydrogen ions together with those of electrons are investigated with a 4-pin probe and a photodetachment (PD) signal of a Langmuir probe. The PD signal is converted to local H(-) density from signal calibration to a scanning cavity ring down PD measurement. Introduction of Cs changes the slope of plasma potential local distribution depending upon the plasma grid bias. A higher electron density H2 plasma locally shields the bias potential and behaves like a metallic free electron gas. On the other hand, the bias and extraction electric fields penetrate in a Cs-seeded electronegative plasma even when the electron density is similar. Electrons are transported by the penetrated electric fields from the driver region along and across the filter and electron deflection magnetic fields. Plasma ions exhibited a completely different response against the penetration of electric fields.

Differential impacts of duration of untreated psychosis (DUP) on cognitive function in first-episode schizophrenia according to mode of onset

Background

The mode of onset and the course of schizophrenia illness exhibit substantial individual variations. Previous studies have pointed out that the mode of onset affects the duration of untreated psychosis (DUP) and clinical outcomes, such as cognitive and social functioning. This study attempted to clarify the association between the DUP and clinical features, taking the different modes of onset into consideration, in a prospective longitudinal study examining patients with first-episode schizophrenia.

Methods

This study was conducted in six areas of Japan. Patients with first-episode schizophrenia were followed for over 18 months. Cognitive function, psychopathology, and social functioning were assessed at baseline and at 6, 12, and 18-month follow-up points.

Results

We identified 168 patients and sufficient information was available to determine the DUP and the mode of onset for 156 patients (92.9%): 79 had an acute onset, and 77 had an insidious onset. The DUP was significantly associated with quality of life (QOL), social functioning, and cognitive function at most of the follow-up points in the insidious-onset group. The DUP and negative symptoms at baseline were significant predictors of cognitive function at the 18-month follow-up in the insidious-onset group.

Conclusions

The present results further support the hypothesis that the DUP affects QOL, social functioning, and cognitive function over the course of illness, especially in patients with an insidious onset. Effective strategies for detecting and caring for individuals with insidious onset early during the course of schizophrenia will be essential for achieving a full patient recovery.

Stiffness matrix representation of hyper-elasticity for surgical simulation and navigation

Nowadays, physics-based simulation plays an important role in industries and clinical fields thanks to the outstanding progress of computer technologies and numerical simulation. One of the demands for the applied technology of physics-based simulation, is the surgical simulation of organ tissue not only for surgical training but also for intra-operative navigation. Although linear Finite Element Method (FEM) is capable of real-time simulation, the conventional FEM analysis does not satisfy the accuracy of non-linear response and interactivity at the same time. The aim of this study is to establish the surgical simulation and navigation to consider hyper-elasticity (HE), which represents the organ's non-linear response material better than the conventional linear material. In this paper, we propose a novel method to decompose the stress-strain relationship of HE, and construct the stiffness matrix for real-time and interactive simulation by extending the linear FEM, which is capable of efficient simulation. The experimental results showed that the proposed method is able to simulate non-linear FEM deformation accurately almost equivalent to the existing non-linear FEM analysis by shorter calculation time. In addition, the deformation with the kidney model was demonstrated.

Severe demyelination but no astrocytopathy in clinically definite neuromyelitis optica with anti-myelin-oligodendrocyte glycoprotein antibody

We report a patient with neuromyelitis optica (NMO) presenting anti-myelin-oligodendrocyte glycoprotein (MOG)-seropositive, in whom biomarkers of demyelination and astrocyte damage were measured during an acute attack. A 31-year-old man developed right optic neuritis followed by longitudinally extensive transverse myelitis, fulfilling the criteria for definite NMO. He was anti-MOG-seropositive and anti-aquaporin-4 seronegative. The myelin basic protein level was markedly elevated whereas glial fibrillary acidic protein was not detectable in cerebrospinal fluid during an acute attack. His symptoms quickly improved after high-dose methylprednisolone therapy. This case suggests that NMO patients with anti-MOG may have severe demyelination in the absence of astrocyte injury.

GNE myopathy associated with congenital thrombocytopenia: a report of two siblings

GNE myopathy is an autosomal recessive muscular disorder caused by mutations in the gene encoding the key enzyme in sialic acid biosynthesis, UDP-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE/MNK). Here, we report two siblings with myopathy with rimmed vacuoles and congenital thrombocytopenia who harbored two compound heterozygous GNE mutations, p.V603L and p.G739S. Thrombocytopenia, which is characterized by shortened platelet lifetime rather than ineffective thrombopoiesis, has been observed since infancy. We performed exome sequencing and array CGH to identify the underlying genetic etiology of thrombocytopenia. No pathogenic variants were detected among the known causative genes of recessively inherited thrombocytopenia; yet, candidate variants in two genes that followed an autosomal recessive mode of inheritance, including previously identified GNE mutations, were detected. Alternatively, it is possible that the decreased activity of GNE/MNK itself, which would lead to decreased sialic content in platelets, is associated with thrombocytopenia in these patients. Further investigations are required to clarify the association between GNE myopathy and the pathogenesis of thrombocytopenia.

Cerebrospinal fluid aquaporin-4 antibody levels in neuromyelitis optica attacks

To elucidate immunopathogenetic roles of aquaporin-4 antibodies in the cerebrospinal fluid (CSF) of neuromyelitis optica spectrum disorders (NMOSD), we analyzed aquaporin-4 antibody titers, cellular and inflammatory markers in the CSF collected from 11 aquaporin-4 antibody seropositive patients. The CSF aquaporin-4 antibody levels during attacks (but not in sera) closely correlated with pleocytosis, inflammatory cytokines including interleukin-6 that can regulate antibody-producing plasmablasts, and glial fibrillary acidic protein levels in the CSF. The amount of aquaporin-4 antibodies present in the central nervous system may have therapeutic implications, as it is associated with astrocyte injury and inflammatory responses during NMOSD attacks. Ann Neurol 2014;76:305–309