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Non-invasive visual evoked potentials to assess optic nerve involvement in the dark agouti rat model of experimental autoimmune encephalomyelitis induced by myelin oligodendrocyte glycoprotein.

ABSTRACT: Experimental autoimmune encephalomyelitis (EAE) is the primary disease model of multiple sclerosis (MS), one of the most diffused neurological diseases characterized by fatigue, muscle weakness, vision loss, anxiety and depression. EAE can be induced through injection of myelin peptides to susceptible mouse or rat strains. In particular, EAE elicited by the autoimmune reaction against myelin oligodendrocyte glycoprotein (MOG) presents the common features of human MS: inflammation, demyelination and axonal loss. Optic neuritis affects visual pathways in both MS and in several EAE models. Neurophysiological evaluation through visual evoked potential (VEP) recording is useful to check visual pathway dysfunctions and to test the efficacy of innovative treatments against optic neuritis. For this purpose, we investigate the extent of VEP abnormalities in the dark agouti (DA) rat immunized with MOG, which develops a relapsing-remitting disease course. Together with the detection of motor signs, we acquired VEPs during both early and late stages of EAE, taking advantage of a non-invasive recording procedure that allows long follow-up studies. The validation of VEP outcomes was determined by comparison with ON histopathology, aimed at revealing inflammation, demyelination and nerve fiber loss. Our results indicate that the first VEP latency delay in MOG-EAE DA rats appeared before motor deficits and were mainly related to an inflammatory state. Subsequent VEP delays, detected during relapsing EAE phases, were associated with a combination of inflammation, demyelination and axonal loss. Moreover, DA rats with atypical EAE clinical course tested at extremely late time points, manifested abnormal VEPs although motor signs were mild. Overall, our data demonstrated that non-invasive VEPs are a powerful tool to detect visual involvement at different stages of EAE, prompting their validation as biomarkers to test novel treatments against MS optic neuritis.

SUBMITTER: Castoldi V

PROVIDER: S-EPMC8018089 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Purpose: To describe a Japanese girl with unilateral optic neuritis who was seropositive for the anti-myelin-oligodendrocyte glycoprotein (MOG). Serial recordings of the pattern visual evoked potentials (pVEPs) were made to follow the dynamic changes of the disease activity. Observations: A 5-year-old girl developed a sudden reduction of vision and deep ocular pain in her right eye. On examination at our university hospital, the best-corrected visual acuity (BCVA) was light perception, and a swelling of the optic disc and tortuous vessels at the posterior pole of the right eye were observed. MRI demonstrated that her right optic nerve was hyperintense on short TI inversion recovery (STIR) sequence. A diagnosis of right papillitis was made, and she was treated with steroid pulse therapy followed by a gradual tapering of oral prednisolone. The visual acuity decreased to no light perception and plasmapheresis combined with high-dose intravenous immunoglobulin therapy was performed. The decimal visual acuity rapidly improved and recovered to 1.2, and no recurrence was observed for at least 1 year. On day 19, she was found to be anti-MOG antibody positive and anti-Aquaporin 4 antibody negative. pVEPs were recorded during the course of the disease process which showed the dynamic changes of the physiology of the visual pathways. The implicit times of the N75 and P100 components were prolonged in the right eye in the acute phase. The right visual acuity remained at 1.2 for at least 1 year, but the implicit times of the N75 and P100 components of the pVEPs of the right eye were still prolonged compared to left eye. Conclusion: Our findings indicate a positive relationship between the anti-MOG antibodies-positivity and the prolonged pVEPs. Further analyses of the pVEPs and other clinical findings of the optic neuritis are needed to establish the clinical significance of the anti-MOG antibodies positivity and optic neuritis for the diagnosis, treatment, and prognosis for this disease.

Project description:ObjectiveWe examined a cohort of adults with aquaporin-4 (AQP4) antibody-negative neuromyelitis optica/neuromyelitis optica spectrum disorder (NMO/NMOSD) for antibodies to myelin oligodendrocyte glycoprotein (MOG).MethodsWe performed a flow cytometry cell-based assay using live human lentivirus-transduced cells expressing full-length surface MOG. Serum was tested in 23 AQP4 antibody-negative NMO/NMOSD patients with bilateral and/or recurrent optic neuritis (BON, n = 11), longitudinally extensive transverse myelitis (LETM, n = 10), and sequential BON and LETM (n = 2), as well as in patients with multiple sclerosis (MS, n = 76) and controls (n = 52).ResultsMOG antibodies were detected in 9/23 AQP4 antibody-negative patients with NMO/NMOSD, compared to 1/76 patients with MS and 0/52 controls (p < 0.001). MOG antibodies were detected in 8/11 patients with BON, 0/10 patients with LETM, and 1/2 patients with sequential BON and LETM. Six of 9 MOG antibody-positive patients had a relapsing course. MOG antibody-positive patients had prominent optic disc swelling and were more likely to have a rapid response to steroid therapy and relapse on steroid cessation than MOG antibody-negative patients (p = 0.034 and p = 0.029, respectively). While 8/9 MOG antibody-positive patients had good follow-up visual acuity, one experienced sustained visual impairment, 3 had retinal nerve fiber layer thinning, and one had residual spinal disability.ConclusionsMOG antibodies have a strong association with BON and may be a useful clinical biomarker. MOG antibody-associated BON is a relapsing disorder that is frequently steroid responsive and often steroid dependent. Failure to recognize the disorder early and institute immunotherapy promptly may be associated with sustained impairment.Classification of evidenceThis study provides Class II evidence that MOG antibodies are associated with AQP4 antibody-negative BON (sensitivity 69%, 95% confidence interval [CI] 42%-87%; specificity 99%, 95% CI 93.7%-99.8%).

Project description:BackgroundKey clinical features of chronic relapsing inflammatory optic neuropathy (CRION) include relapsing inflammatory optic neuritis (ON) and steroid dependency, both of which have been reported among patients with myelin oligodendrocyte glycoprotein antibodies (MOG-Abs). We investigated the relevance of the presence of serum MOG-IgG with the current diagnostic criteria for CRION among patients with idiopathic inflammatory optic neuritis (iON).MethodsRetrospective reviews of a database prospectively collated between 2011 and 2017 from the tertiary referral center for multiple sclerosis and neuromyelitis optica were performed. Sixty-four patients with iON, who did not meet the diagnostic criteria for multiple sclerosis, neuromyelitis optica (NMO) spectrum disorder with/without NMO-IgG, or acute disseminated encephalomyelitis and who had no symptomatic central nervous system (CNS) lesions other than on the optic nerve, were included from a cohort of 615 patients with inflammatory demyelinating diseases of the CNS. Fulfillment of the current diagnostic criteria for CRION, assay results for the serum IgG1 MOG-Ab, and characteristics of CRION patients with MOG-IgG were compared to those of non-CRION patients with MOG-IgG.ResultsTwelve iON patients fulfilled the current diagnostic criteria for CRION, 11 patients were positive for MOG-IgG, and one patient was borderline. Among the other 52 iON patients not meeting the criteria for CRION, 14 had relapsing disease courses and 38 had monophasic courses, of which MOG-IgG positivity were 0% and 29%, respectively. CRION patients with MOG-IgG had more relapsing disease courses (first steroid-dependent worsening/relapse in 2.3 months, range 0.4-7.0) and poorer optical coherence tomography outcomes at follow-up than non-CRION patients with MOG-IgG. However, patients in the two groups did not differ in terms of age of onset, sex, or steroid treatment duration after initial attack.ConclusionsCRION, according to the current diagnostic criteria, is a relapsing optic neuritis associated with MOG-IgG. Among iON patients with MOG-IgG, the absence of steroid-dependent attacks in the early stages of the disease may predict a long-term non-relapsing disease course and a more favorable outcome.

Project description:Background: Myelin oligodendrocyte glycoprotein (MOG) antibody associated encephalomyelitis is increasingly being considered a distinct disease entity, with seizures and encephalopathy commonly reported. We investigated the clinical features of MOG-IgG positive patients presenting with seizures and/or encephalopathy in a single cohort. Methods: Consecutive patients with suspected idiopathic inflammatory demyelinating diseases were recruited from a tertiary University hospital in Guangdong province, China. Subjects with MOG-IgG seropositivity were analyzed according to whether they presented with or without seizure and/or encephalopathy. Results: Overall, 58 subjects seropositive for MOG-IgG were analyzed, including 23 (40%) subjects presenting with seizures and/or encephalopathy. Meningeal irritation (P = 0.030), fever (P = 0.001), headache (P = 0.001), nausea, and vomiting (P = 0.004) were more commonly found in subjects who had seizures and/or encephalopathy, either at presentation or during the disease course. Nonetheless, there was less optic nerve (4/23, 17.4%, P = 0.003) and spinal cord (6/16, 37.5%, P = 0.037) involvement as compared to subjects without seizures or encephalopathy. Most MOG encephalomyelitis subjects had cortical/subcortical lesions: 65.2% (15/23) in the seizures and/or encephalopathy group and 50.0% (13/26) in the without seizures or encephalopathy group. Cerebrospinal fluid (CSF) leukocytes were elevated in both groups. Subgroup analysis showed that 30% (7/23) MOG-IgG positive subjects with seizures and/or encephalopathy had been misdiagnosed for central nervous system infection on the basis of meningoencephalitis symptoms and elevated CSF leukocytes (P = 0.002). Conclusions: Seizures and encephalopathy are not rare in MOG encephalomyelitis, and are commonly associated with cortical and subcortical brain lesions. MOG-encephalomyelitis often presents with clinical meningoencephalitis symptoms and abnormal CSF findings mimicking central nervous system infection in pediatric and young adult patients.

Project description:BACKGROUND: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS). It is associated with local activation of microglia and astroglia, infiltration of activated macrophages and T cells, active degradation of myelin and damage to axons and neurons. The proposed role for CX3CL1 (fractalkine) in the control of microglia activation and leukocyte infiltration places this chemokine and its receptor CX3CR1 in a potentially strategic position to control key aspects in the pathological events that are associated with development of brain lesions in MS. In this study, we examine this hypothesis by analyzing the distribution, kinetics, regulation and cellular origin of CX3CL1 and CX3CR1 mRNA expression in the CNS of rats with an experimentally induced MS-like disease, myelin oligodendrocyte glycoprotein (MOG)-induced autoimmune encephalomyelitis (EAE). METHODS: The expression of CX3CL1 and its receptor CX3CR1 was studied with in situ hybridization histochemical detection of their mRNA with radio labeled cRNA probes in combination with immunohistochemical staining of phenotypic cell markers. Both healthy rat brains and brains from rats with MOG EAE were analyzed. In defined lesional stages of MOG EAE, the number of CX3CR1 mRNA-expressing cells and the intensity of the in situ hybridization signal were determined by image analysis. Data were statistically evaluated by ANOVA, followed by Tukey\primes multiple comparison test. RESULTS: Expression of CX3CL1 mRNA was present within neuronal-like cells located throughout the neuraxis of the healthy rat. Expression of CX3CL1 remained unaltered in the CNS of rats with MOG-induced EAE, with the exception of an induced expression in astrocytes within inflammatory lesions. Notably, the brain vasculature of healthy and encephalitic animals did not exhibit signs of CX3CL1 mRNA expression. The receptor, CX3CR1, was expressed by microglial cells in all regions of the healthy brain. Induction of MOG-induced EAE was associated with a distinct accumulation of CX3CR1 mRNA expressing cells within the inflammatory brain lesions, the great majority of which stained positive for markers of the microglia-macrophage lineage. Analysis in time-staged brain lesions revealed elevated levels of CX3CR1 mRNA in microglia in the periplaque zone, as well as a dramatically enhanced accumulation of CX3CR1 expressing cells within the early-active, late-active and inactive, demyelinated lesions. CONCLUSION: Our data demonstrate constitutive and regulated expression of the chemokine CX3CL1 and its receptor CX3CR1 by neurons/astrocytes and microglia, respectively, within the normal and inflamed rat brain. Our findings propose a mechanism by which neurons and reactive astrocytes may control migration and function of the surrounding microglia. In addition, the accumulation of CX3CR1 expressing cells other than microglia within the inflammatory brain lesions indicate a possible role for CX3CL1 in controlling invasion of peripheral leucocytes to the brain.

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Non-invasive visual evoked potentials to assess optic nerve involvement in the dark agouti rat model of experimental autoimmune encephalomyelitis induced by myelin oligodendrocyte glycoprotein.

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