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Frontiers in Neurology 2023New neurological complications of COVID-19 infection have been reported in recent research. Among them, the spectrum of anti-MOG positive diseases, defined as anti-MOG...
BACKGROUND
New neurological complications of COVID-19 infection have been reported in recent research. Among them, the spectrum of anti-MOG positive diseases, defined as anti-MOG antibody associated disease (MOGAD), is distinguished, which can manifest as optic neuritis, myelitis, or various forms of encephalitis (MOGAE).
MATERIALS AND METHODS
This study reports a new case of MOGAE following SARS-CoV-2 infection. A literature review of other MOGAE cases associated with COVID-19 infection was conducted and summarized.
RESULTS
A 60-year-old male patient, who had previously been infected with COVID-19, was admitted to the Neurology Department with a rapidly progressive deterioration of his cognitive functions that lasted for about 3 months. On neurological examination, the Mini-Mental State Examination (MMSE) score was 17, which further deteriorated to 13. In addition, central paresis of the right VIIth nerve and pyramidal hemiparesis on the right side were noted. The MRI of the brain showed multiple hyperintense lesions. The CSF examination revealed an elevated total protein level with a normal cell count, and serum showed a positive finding of anti-MOG antibodies. Taking into account all the information, the diagnosis of MOGAE, following COVID-19 infection, was made. A total of 9 similar cases of MOGAE associated with SARS-CoV-2 infection were identified in the available literature. Among them 2 cases presented progressive cognitive dysfunction and another 5 altered mental status. The most frequently described MRI changes were hyperintense lesions located cortically and/or subcortically. Anti-MOG antibodies were positive in all patients. In 5 cases they were detected only in serum, in 2 cases in serum and CSF, and in 2 cases the origin was not reported.
CONCLUSION
The reported cases of MOGAE following COVID-19 infection suggest an increasing new clinical problem, and show an association between COVID-19 and MOGADs.
PubMed: 37638199
DOI: 10.3389/fneur.2023.1239657 -
Frontiers in Cellular Neuroscience 2023Imbalance between excitation and inhibition in the cerebral cortex is one of the main theories in neuropsychiatric disorder pathophysiology. Cortical inhibition is...
Imbalance between excitation and inhibition in the cerebral cortex is one of the main theories in neuropsychiatric disorder pathophysiology. Cortical inhibition is finely regulated by a variety of highly specialized GABAergic interneuron types, which are thought to organize neural network activities. Among interneurons, axo-axonic cells are unique in making synapses with the axon initial segment of pyramidal neurons. Alterations of axo-axonic cells have been proposed to be implicated in disorders including epilepsy, schizophrenia and autism spectrum disorder. However, evidence for the alteration of axo-axonic cells in disease has only been examined in narrative reviews. By performing a systematic review of studies investigating axo-axonic cells and axo-axonic communication in epilepsy, schizophrenia and autism spectrum disorder, we outline convergent findings and discrepancies in the literature. Overall, the implication of axo-axonic cells in neuropsychiatric disorders might have been overstated. Additional work is needed to assess initial, mostly indirect findings, and to unravel how defects in axo-axonic cells translates to cortical dysregulation and, in turn, to pathological states.
PubMed: 37435048
DOI: 10.3389/fncel.2023.1212202 -
Frontiers in Cellular Neuroscience 2022Various cortical functions arise from the dynamic interplay of excitation and inhibition. GABAergic interneurons that mediate synaptic inhibition display significant...
Various cortical functions arise from the dynamic interplay of excitation and inhibition. GABAergic interneurons that mediate synaptic inhibition display significant diversity in cell morphology, electrophysiology, plasticity rule, and connectivity. These heterogeneous features are thought to underlie their functional diversity. Emerging attention on specific properties of the various interneuron types has emphasized the crucial role of cell-type specific inhibition in cortical neural processing. However, knowledge is still limited on how each interneuron type forms distinct neural circuits and regulates network activity in health and disease. To dissect interneuron heterogeneity at single cell-type precision, we focus on the chandelier cell (ChC), one of the most distinctive GABAergic interneuron types that exclusively innervate the axon initial segments (AIS) of excitatory pyramidal neurons. Here we review the current understanding of the structural and functional properties of ChCs and their implications in behavioral functions, network activity, and psychiatric disorders. These findings provide insights into the distinctive roles of various single-type interneurons in cortical neural coding and the pathophysiology of cortical dysfunction.
PubMed: 36299494
DOI: 10.3389/fncel.2022.992409 -
Frontiers in Neuroscience 2019Hereditary spastic paraplegia (HSP) and hereditary ataxia (HA) are two groups of disorders characterized, respectively, by progressive dysfunction or degeneration of the...
Hereditary spastic paraplegia (HSP) and hereditary ataxia (HA) are two groups of disorders characterized, respectively, by progressive dysfunction or degeneration of the pyramidal tracts (HSP) and of the Purkinje cells and spinocerebellar tracts (HA). Although HSP and HA are generally shown to have distinct clinical-genetic profiles, in several cases the clinical presentation, the causative genes, and the cellular pathways and mechanisms involved overlap between the two forms. Genetic analyses in humans in combination with and studies using model systems have greatly expanded our knowledge of spinocerebellar degenerative disorders. In this review, we focus on the zebrafish (), a vertebrate model widely used in biomedical research since its overall nervous system organization is similar to that of humans. A critical analysis of the literature suggests that zebrafish could serve as a powerful experimental tool for molecular and genetic dissection of both HA and HSP. The zebrafish, found to be very useful for demonstrating the causal relationship between defect and mutation, also offers a useful platform to exploit for the development of therapies.
PubMed: 31920481
DOI: 10.3389/fnins.2019.01311 -
Critical Reviews in Oncology/hematology Jul 2015Erdheim-Chester disease (ECD) is a rare form of non-Langerhans-cell histiocytosis, associated in more than 50% of cases to BRAF(V600E) mutations in early multipotent... (Review)
Review
Erdheim-Chester disease (ECD) is a rare form of non-Langerhans-cell histiocytosis, associated in more than 50% of cases to BRAF(V600E) mutations in early multipotent myelomonocytic precursors or in tissue-resident histiocytes. It encompasses a spectrum of disorders ranging from asymptomatic bone lesions to multisystemic, life-threatening variants. We reviewed all published reports of histologically-confirmed ECD and explored clinical, radiological, prognostic and therapeutic characteristics in a population of 448 patients, including a unique patient from our Department. To find a clinically relevant signature defining differentiated prognostic profiles, the patients' disease features were compared in relation to their CNS involvement that occurred in 56% of the entire population. Diabetes insipidus, visual disturbances, pyramidal and extra-pyramidal syndromes were the most recurrent neurological signs, whereas concomitant pituitary involvement, retro-orbital masses and axial lesions in the presence of symmetric bilateral osteosclerosis of long bones depicted the typical ECD clinical picture. Patients with CNS infiltration showed a lower occurrence of heart involvement and a higher incidence of bone, skin, retro-peritoneal, lung, aortic and renal infiltration. No difference in the therapeutic algorithm was found after stratification for CNS involvement. A better understanding of the disease pathogenesis, including BRAF deregulation, in keeping with improved prognostic criteria, will provide novel suggestions for the management of ECD.
Topics: Adrenal Cortex Hormones; Adult; Bone and Bones; Central Nervous System; Erdheim-Chester Disease; Humans; Kidney; Male; Myocardium; Point Mutation; Prognosis; Proto-Oncogene Proteins B-raf
PubMed: 25744785
DOI: 10.1016/j.critrevonc.2015.02.004 -
Epilepsy Research Oct 2014The utility of MRI-based hippocampal subfield volumetry as a diagnostic test for hippocampal sclerosis (HS) is based on the hypothesis that specific hippocampal... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
The utility of MRI-based hippocampal subfield volumetry as a diagnostic test for hippocampal sclerosis (HS) is based on the hypothesis that specific hippocampal subfields are differentially affected in HS. While qualitative studies suggest selective involvement of certain hippocampal subfields in this condition, whether quantifiable differences exist remains unclear. Neuronal density measurement is the most widely used technique for measuring subfield pathological change in HS. Therefore, a systematic review and meta-analysis of studies reporting neuronal densities in temporal lobe epilepsy was performed in order to quantify subfield pathology in hippocampal sclerosis.
METHODS
Studies were identified by searching the Medline and Embase databases using the search terms: cell count, hippocampus, and epilepsy. Of the 192 studies identified by the literature search, seven met all inclusion and exclusion criteria. Random effects meta-analyses were performed, comparing: (i) neuronal densities in control (n=121) versus HS (n=371) groups for subfields CA1-4; and (ii) amount of neuronal loss in HS between subfields CA1-4.
RESULTS
Statistically significant neuronal loss was observed comparing HS to control groups in all subfields CA1-4 (p<0.001 for all comparisons). Significantly greater neuronal loss was demonstrated in HS comparing CA1 versus CA2 (p<0.001), CA3 (p=0.005), and CA4 (p=0.003). Greater pyramidal cell loss was also demonstrated in CA3 relative to the CA2 subfield (p=0.003). No significant differences were identified comparing CA2 and CA4 (p=0.39); or comparing CA3 and CA4 (p=0.64).
CONCLUSIONS
HS is characterized by pathology in all hippocampal subfields. Quantifiable differences exist in the involvement of specific hippocampal subfields in HS. Neuronal loss is greatest in CA1, intermediate in CA3 and CA4, and least in CA2. Further studies are required to determine if this pattern can be detected using in vivo MRI.
Topics: Cell Count; Epilepsy; Hippocampus; Humans; Neurons; Sclerosis
PubMed: 25107686
DOI: 10.1016/j.eplepsyres.2014.07.003