Dataset Information

Differentially Altered NMDAR Dependent and Independent Long-Term Potentiation in the CA3 Subfield in a Model of Anti-NMDAR Encephalitis.

ABSTRACT: Purpose: Autoantibodies against NMDA receptors (NMDAR) in the cerebrospinal fluid (CSF) from anti-NMDAR encephalitis patients have been suggested to be pathogenic since in previous studies using patient CSF, NMDAR-dependent processes such as long-term potentiation (LTP) were compromised. However, autoantibodies may represent a family of antibodies targeted against different epitopes, and CSF may contain further autoantibodies. Here, we tested the specificity of the autoantibody by comparing NMDAR-dependent and NMDAR-independent LTP within the same hippocampal subfield, CA3, using CSF samples from four anti-NMDAR encephalitis patients and three control patients. Methods: We performed a stereotactic injection of patient-derived cell-free CSF with proven presence or absence of NMDAR-antibodies into the rat hippocampus in vivo. Hippocampal brain slices were prepared 1-8 days after intrahippocampal injection, and NMDAR-dependent LTP at the associational-commissural (A/C) fiber-CA3 synapse was compared to NMDAR-independent LTP at the mossy fiber (MF)-CA3 synapse. Results: The LTP magnitude at A/C fiber-CA3 synapses in slices from control-CSF-treated animals (168 ± 8% n = 54) was significantly higher than LTP in slices from NMDAR-CSF-treated animals (139 ± 9%, n = 40; P = 0.015), although there was some variation between the individual CSF samples. We found residual LTP in NMDAR-CSF-treated tissue which could be abolished by the NMDAR inhibitor D-AP5. Moreover, the CA3 field excitatory postsynaptic potential (fEPSP) was followed by epileptiform afterpotentials in 5% of slices (4/78) from control-CSF-treated animals, but in 26% of slices (12/46) from NMDAR-CSF-treated animals (P = 0.002). Application of the LTP-inducing paradigm increased the proportion of slices with epileptiform afterpotentials, but D-AP5 significantly reduced the occurrence of epileptiform afterpotentials only in NMDAR-CSF-treated, but not in control tissue. At the MF synapse, no significant difference in LTP values of control-CSF and in NMDAR-CSF-treated tissue was observed indicating that NMDAR-independent MF-LTP is intact in NMDAR-CSF-treated tissue. Conclusion: These findings indicate that anti-NMDAR containing CSF impairs LTP at the A/C fiber-CA3 synapse, although there is substantial variation among CSF samples suggesting different epitopes among patient-derived antibodies. The differential inhibition of LTP at this synapse in contrast to the MF-CA3 synapse suggests the specificity and underlines the pathophysiological role of the NMDAR-antibody.

SUBMITTER: Blome R

PROVIDER: S-EPMC6079239 | biostudies-literature | 2018

REPOSITORIES: biostudies-literature

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Differentially Altered NMDAR Dependent and Independent Long-Term Potentiation in the CA3 Subfield in a Model of Anti-NMDAR Encephalitis.

Blome Roman R Bach Willi W Guli Xiati X Porath Katrin K Sellmann Tina T Bien Christian G CG Köhling Rüdiger R Kirschstein Timo T

Frontiers in synaptic neuroscience 20180731

<b>Purpose</b>: Autoantibodies against NMDA receptors (NMDAR) in the cerebrospinal fluid (CSF) from anti-NMDAR encephalitis patients have been suggested to be pathogenic since in previous studies using patient CSF, NMDAR-dependent processes such as long-term potentiation (LTP) were compromised. However, autoantibodies may represent a family of antibodies targeted against different epitopes, and CSF may contain further autoantibodies. Here, we tested the specificity of the autoantibody by compari ...[more]

PMID: 30108497

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Project description:ObjectiveTo investigate the nature of prodromal headache in anti-NMDA receptor (NMDAR) encephalitis.MethodsRetrospective review of the clinical information of 39 patients with anti-NMDAR encephalitis admitted between January 1999 and September 2017. Five patients with an atypical presentation were excluded. Thus, in 34 patients (median 27 years [range, 12-47 years]; 28 [82%] female), the clinical features were compared between patients who initially reported headache and those who did not report.ResultsTwenty-two patients (65%) reported headache either transiently (n = 5) or continuously (n = 17). Encephalitic symptoms (psychobehavioral memory alterations, seizure, dyskinesias, or altered level of consciousness) developed in 20 patients with median 5.5 days (range, 1-29 days) after headache onset. In one patient, NMDAR antibodies were detected in CSF 3 days after headache onset. Patients with headache had more frequently fever (14/22 [64%] vs. 2/12 [17%] p = 0.013) and higher CSF pleocytosis (median white blood cells 79/?l [range, 6-311/?l] vs. 30/?l [range, 2-69/?l], p = 0.035) than those without headache, but there was no difference in gender, age at onset, seizure, migraine, CSF oligoclonal band detection, elevated IgG index, tumor association, or brain MRI abnormalities between them.ConclusionsHeadache often developed with fever and pleocytosis, but it was rapidly replaced by psychiatric symptoms. Based on current knowledge on the antibody-mediated mechanisms that cause a decrease of synaptic NMDAR through crosslinking and internalization leading to a state mimicking "dissociative anesthesia," we speculated that prodromal headache is not likely caused by direct effect of the autoantibodies but rather meningeal inflammation (noninfectious aseptic meningitis) that occurs in parallel to intrathecal antibody synthesis as an epiphenomenon of NMDAR autoimmunity. Psychobehavioral alterations following headache is an important clue to the diagnosis.

Project description:OBJECTIVE:To determine whether neurophysiological mechanisms indicating cortical excitability, long-term potentiation (LTP)-like plasticity, GABAergic and glutamatergic function are altered in patients with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis and whether they can be helpful as markers of diagnostic assessment, disease progression, and potentially therapy response. METHODS:Neurophysiological characterizations of patients with NMDAR encephalitis (n = 34, mean age: 28 ± 11 years; 30 females) and age/gender-matched healthy controls (n = 27, 28.5 ± 10 years; 25 females) were performed using transcranial magnetic stimulation-derived protocols including resting motor threshold, recruitment curve, intracortical facilitation, short intracortical inhibition, and cortical silent period. Paired associative stimulation (PAS) was applied to assess LTP-like mechanisms which are mediated through NMDAR. Moreover, resting state functional connectivity was determined using functional magnetic resonance imaging. RESULTS:PAS-induced plasticity differed significantly between groups (P = 0.0056). Cortical excitability, as assessed via motor-evoked potentials after PAS, decreased in patients, whereas it increased in controls indicating malfunctioning of NMDAR in encephalitis patients. Lower PAS-induced plasticity significantly correlated with the modified Rankin Scale (mRS) (r = -0.41; P = 0.0031) and was correlated with lower functional connectivity within the motor network in NMDAR encephalitis patients (P < 0.001, uncorrected). Other neurophysiological parameters were not significantly different between groups. Follow-up assessments were available in six patients and demonstrated parallel improvement of PAS-induced plasticity and mRS. INTERPRETATION:Assessment of PAS-induced plasticity may help to determine NMDAR dysfunction and disease severity in NMDAR encephalitis, and might even aid as a sensitive, noninvasive, and well-tolerated "electrophysiological biomarker" to monitor therapy response in the future. CLINICAL TRIAL REGISTRATION:ClinicalTrials.gov: Identifier: NCT01865578.

Project description:Background Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis is one of the most prevalent autoimmune encephalitis and is closely related to catatonia. This study aimed to investigate the clinical features and disease outcomes of adult catatonic anti-NMDAR encephalitis patients. Methods Adult patients diagnosed with anti-NMDAR encephalitis between January 2013 and October 2021 were retrospectively enrolled in this study. According to the Bush Francis Catatonia screening instrument (BFCSI), patients were divided into two groups: those with catatonia and those without catatonia. The modified Rankin scale (mRS), Clinical Assessment Scale for Autoimmune Encephalitis (CASE), Neuropsychiatric Inventory (NPI), Patient Health Questionnaire-9 (PHQ-9) and 7-item Generalized Anxiety Disorder Questionnaire (GAD-7) scores were assessed at follow-up. The Mann–Whitney U test (nonparametric), Student’s t test (parametric), and chi-squared test were used to analyse the differences between the two groups. Results Eighty-four patients were recruited, including twenty-five catatonic patients and fifty-nine noncatatonic patients. Among them, 28 had positive antibody only in cerebrospinal fluid (CSF), 4 had positive antibody only in serum and 52 had positive antibody both in CSF and serum. Catatonic patients experienced more disturbance of consciousness (p = 0.01), aggression (p = 0.046) and affective disorders (p = 0.043) than noncatatonic patients. The mRS scores of the catatonia group assessed at admission (p = 0.045) were worse than those of the non-catatonia group. Catatonic patients were more inclined to develop deep vein thrombosis (p = 0.003), decubitus (p = 0.046), pneumonia (p = 0.025), and to be admitted to the intensive care unit (ICU) (p = 0.011) than noncatatonic patients. All patients in the catatonia group received first-line immunotherapy. At the 24-month follow-up, 2 patients in the catatonia group did not achieve good outcomes. At the last follow-up, the catatonia group had more relapses (p = 0.014) and more neuropsychiatric problems (p = 0.035). Conclusions Adult anti-NMDAR encephalitis patients with catatonia present distinct clinical features in disease course and are prone to experience more relapses and long-term neuropsychiatric problems than those without catatonia. Supplementary Information The online version contains supplementary material available at 10.1186/s12888-022-04505-x.

Dataset Information

Differentially Altered NMDAR Dependent and Independent Long-Term Potentiation in the CA3 Subfield in a Model of Anti-NMDAR Encephalitis.

Publications

Differentially Altered NMDAR Dependent and Independent Long-Term Potentiation in the CA3 Subfield in a Model of Anti-NMDAR Encephalitis.

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