Focal Demyelination Research Articles

Restore axonal conductance in a locally demyelinated axon with electromagnetic stimulation.

Axonal demyelination leads to failure of axonal conduction. Current research on demyelination focuses on the promotion of remyelination. Electromagnetic stimulation is widely used to promote neural activity. We hypothesized that electromagnetic stimulation of the demyelinated area, by providing excitation to the nodes of Ranvier, could rescue locally demyelinated axons from conductance failure. 
Approach: We built a multi-compartment NEURON model of a myelinated axon under electromagnetic stimulation. We simulated the action potential propagation and observed conductance failure when local demyelination occurred. Conductance failure was due to current leakage and a lack of activation of the nodes in the demyelinated region. To investigate the effects of electromagnetic stimulation on locally demyelinated axons, we positioned a miniature coil next to the affected area to activate nodes in the demyelinated region. 
Main results: Subthreshold microcoil stimulation caused depolarization of node membranes. This depolarization, in combination with membrane depolarization induced by the invading action potential, resulted in sufficient activation of nodes in the demyelinated region and restoration of axonal conductance. Efficacy of restoration was dependent on the amplitude and frequency of the stimuli, and the location of the microcoil relative to the targeted nodes. The restored axonal conductance was due to the enhanced Na+ current and reduced K+ current in the nodes, rather than a reduction in leakage current in the demyelinated region. Finally, we found that microcoil stimulation had no effect on axonal conductance in healthy, myelinated axons. 
Significance: Activation of nodes in the demyelinated region using electromagnetic stimulation provides an alternative treatment strategy to restore axonal function under local demyelination conditions. Results provide insights to the development of microcoil technology for the treatment of focal segmental demyelination cases, such as neuropraxia, spinal cord injury, and auditory nerve demyelination. &#xD.

Forceps minor control of social behaviour.

The PRISM project, funded by the EU's Innovative Medicines Initiative, has identified a transdiagnostic, pathophysiological relationship between the integrity of the default mode network (DMN) and social dysfunction. To explore the causal link between DMN integrity and social behaviour, we employed a preclinical back-translation approach, using focal demyelination of the forceps minor to disrupt DMN connectivity in mice. By applying advanced techniques such as functional ultrasound imaging and automated analysis of social behaviour, we demonstrated that reduced DMN connectivity leads to impaired social interactions and increased anxiety in mice. Notably, these effects were reversible, indicating that the forceps minor, a critical fibre tract connecting key DMN regions in the prefrontal cortex, plays a crucial role in social function. This study provides direct evidence for a causal relationship between DMN integrity and social dysfunction, with potential implications for developing targeted treatments in precision psychiatry.

Myelin Imaging of the Spinal Cord in Animal Models and Patients with Multiple Sclerosis Using [11C]MeDAS PET: A Translational Study.

Multiple sclerosis (MS) is a neurodegenerative disease characterized by demyelinated lesions in the brain and spinal cord. A few clinical studies using PET to image myelin in the brain have been performed, but none investigated the spinal cord. Because clinically relevant motor symptoms are primarily due to spinal cord damage, this translational study evaluated [11C]N-methyl-4,4'-diaminostilbene (MeDAS) as a PET tracer for myelin imaging in the rat and human spinal cord. Methods: [11C]MeDAS PET of the spinal cord was conducted in experimental autoimmune encephalomyelitis, lysophosphatidylcholine, and spinal cord injury animal models of focal demyelination. Then, 6 healthy controls and 11 MS patients were subjected to MRI and [11C]MeDAS PET of the spinal cord between C5 and T6 vertebrae. Regions of interest covering 100%, 60%, and 40% of the diameter of the spinal canal were drawn, and tracer uptake was normalized to the activity in the blood pool, muscle, or injected dose per unit of body weight (SUV). Results: [11C]MeDAS uptake was significantly reduced in spinal cord lesions in all animal models. In humans, tracer uptake was significantly higher in the cervical than the thoracic spinal cord, which corresponds well with the known physiologic rostral-caudal gradient in myelin density. MS patients had significantly lower [11C]MeDAS uptake in the upper spinal cord (C5-T3) than did controls. The [11C]MeDAS PET signal was inversely correlated with the presence of MS lesions in specific sections of the spinal cord. The best differentiation among regions with different myelin density was obtained when the smallest region of interest was used and spinal cord uptake was expressed as SUV. Conclusion: [11C]MeDAS PET shows the potential to quantify myelin density in the spinal cord. It enables detection of physiologic differences in myelin density between spinal cord segments and between MS patients and healthy controls, which warrants further evaluation of this technique.

Возможности искусственного интеллекта в характеристике очагов демилинизации пациентов с рассеянным склерозом

INTRODUCTION. Magnetic resonance imaging (MRI) of the central nervous system (CNS) is the method of choice in patients with clinical manifestations of multiple sclerosis (MS) to determine dissemination in space and time according to McDonald diagnostic criteria. Being an important diagnostic tool, tomography also acts as a method for further monitoring of the condition, including for assessing the subclinical course of the disease. The multiplicity of demyelination foci and the discrete nature of the course are an obstacle to a quick and accurate analysis of the volume of changes that have occurred. The automated system for analyzing MRI scans "Brain Snitch", developed by the Department of Nervous and Neurosurgical Diseases together with the Laboratory of Information and Computer Technologies of the Research Institute of the Belarusian State Medical University, allows tracking the current state of the lesion: the degree of activity of the pathological process, the size of the lesion, its localization and intensity. AIM. Evaluation of the state of absolute brightness of active demyelination foci in patients with MS using the automated system "Brain Snitch", based on the work of artificial intelligence. MATERIALS AND METHODS. Scans of various sequences of MRI studies (T1, T1 with contrast, T2, T2 FLAIR) of MRI studies of patients with MS. Active demyelination lesions visualized in T1 mode on MRI were compared with similar lesions in T2 and T2 FLAIR modes in the Brain Snitch program to obtain tabular values of absolute brightness (intensity equivalent, presented by the program using the artificial intelligence technology of the automated Brain Snitch program) of these lesions. RESULTS AND DISCUSSION. Using the automated Brain Snitch program based on artificial intelligence technology, a tendency towards reduced absolute brightness of active demyelination lesions (p = 0.046) was found, compared with the absolute brightness values in T2 mode of lesions similar to inactive (not accumulating contrast agent) in T1 mode. CONCLUSIONS. The tendency found in the course of the study to a reduced absolute brightness of active foci in the T2 mode may serve as a basis for the development of additional criteria for evaluating the activity of pathomorphological foci in multiple sclerosis in radiological and neurological practice.

Modulation of OPC Mitochondrial Function by Inhibiting USP30 Promotes Their Differentiation.

Multiple lines of evidence indicate that mitochondrial dysfunction occurs in demyelinating diseases, such as multiple sclerosis (MS). Failure of remyelination is thought to be caused in part by a block of oligodendrocyte progenitor cell (OPC) differentiation into oligodendrocytes, which generate myelin sheaths around axons. The process of OPC differentiation requires a substantial amount of energy and high demand for ATP which is supplied through the mitochondria. In this study, we highlight mitochondrial gene expression changes during OPC differentiation in two murine models of remyelination and in human postmortem MS brains. Given these transcriptional alterations, we then investigate whether genetic alteration of USP30, a mitochondrial deubiquitinase, enhances OPC differentiation and myelination. By genetic knockout of USP30, we observe increased OPC differentiation and myelination without affecting OPC proliferation and survival in invitro and exvivo assays. We also find that OPC differentiation is accelerated invivo following focal demyelination in USP30 knockout mice. The promotion of OPC differentiation and myelination observed is associated with increased oxygen consumption rates in USP30 knockout OPCs. Together, these data indicate a role for mitochondrial function and USP30 in OPC differentiation and myelination.

Validation of a Set of Clinical Criteria for the Diagnosis of Secondary Progressive Multiple Sclerosis.

Background/Objectives: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system characterized by progressive impairment of neuronal transmission due to focal demyelination. The most common form is RRMS (relapsing-remitting multiple sclerosis), which, under the influence of certain factors, can progress to SPMS (secondary progressive multiple sclerosis). Our study aimed to validate the criteria proposed by a working group of the Romanian Society of Neurology versus the criteria proposed by a group of experts from Spain, Karolinska, and Croatia concerning the progression from RRMS to SPMS. Methods: This was done by gathering epidemiological data (age, gender) and by applying clinical tests such as the 9HPT (9-hole peg test), 25FWT (25-foot walk test), and EDSS (expanded disability status scale) tests and the SDMT test (symbol digit modalities test). The present research is a cohort study that included a number of 120 patients diagnosed with MS according to the McDonald Diagnostic Criteria 2017. The study was carried out between January 2023 and April 2024, including patients hospitalized in the Neurology Clinic of the Clinical Rehabilitation Hospital from Iasi, Romania. The data were collected at baseline (T0) and at a 12-month interval (T1). Results: The statistical analysis was conducted using Kaiser-Meyer-Olkin analysis, which indicated a value of 0.683, thus validating the clinical tests used. The correlation matrix and the linear regression for all the tests showed highly significant statistical results. Furthermore, the ROC curve analysis of the criteria suggested by the working group of the Romanian Society of Neurology demonstrated that the EDSS, 9HPT, and 25FWT are highly sensitive in diagnosing SPMS, an opinion that is shared with the Spanish experts, but not with the Karolinska expert panel. Using the criteria given by the Croatian expert group in the ROC curve analysis showed that only the EDSS was strongly significant for the progression to the SPMS phase. Conclusions: In conclusion, all clinical methods used demonstrated that they are valid and can contribute to identifying patients with an increased risk of progression. The model proposed by the Romanian Society of Neurology working group is similar to other countries' expert opinions and can be used to detect the risk of disease progression and establish a more tailored therapeutic management of SPMS.

Resting state functional magnetic resonance imaging in patients with multiple sclerosis before and after high-dose immunosuppressive therapy and autologous hemopoietic stem cell transplantation

BACKGROUND: Multiple sclerosis is a chronic autoimmune disease characterized by multifocal foci of demyelination in the central nervous system, usually affecting people of working age. The disease causes damage to the blood-brain barrier, the development of multifocal inflammation, destruction of the myelin sheath of axons and various degrees of damage. It is clinically manifested by restriction of motor activity, visual acuity, as well as other symptoms leading to loss of performance and disability of the patient. AIM: determination of changes in the functional connectivity of brain neural networks in patients with multiple sclerosis before and after high-dose immunosuppressive therapy and autologous hematopoietic stem cell transplantation by performing functional magnetic resonance imaging at rest. MATERIALS AND METHODS: The data of functional magnetic resonance imaging of patients with multiple sclerosis were analyzed in dynamics before and after the use of high-dose immunosuppressive therapy followed by autologous hematopoietic stem cell transplantation. The study involved 25 patients with a verified diagnosis of multiple sclerosis. Each underwent complex magnetic resonance imaging at two time points (before and after high-dose immunosuppressive therapy followed by autologous hematopoietic stem cell transplantation) with a difference of 12 months, which included structural magnetic resonance imaging - in order to exclude the presence of pathological foci in the brain (in addition to foci of multiple sclerosis) and functional magnetic resonance imaging.-resonance imaging at rest — to assess functional connectivity. Also, according to the method generally accepted in classical neurology, a clinical neurological examination was performed. RESULTS: At the stage of comparing data on the two groups obtained using functional magnetic resonance imaging at rest, changes in functional activity were detected in various parts of the brain, presumably responsible for clinical differences in the studied groups. CONCLUSION: Currently, the links between brain structures and morphological changes that cause cognitive impairment in multiple sclerosis are being studied. To predict the progression of the disease, the development of biomarkers, including those based on functional magnetic resonance imaging, is required. Evaluating changes in the functional connectivity of brain neural networks can help personalize therapeutic and rehabilitation approaches.

Focal slowing of nerve conduction velocity in leprosy patients unveiled through multisegmented nerve analysis.

Leprosy is a chronic infectious disease caused by Mycobacterium leprae (M. leprae), an intracellular bacillus that systematically invades the peripheral nerves. Diagnosing leprosy neuropathy is still a defying skill, and late diagnosis and treatment are still a reality. Based on the biological characteristics of M. leprae, particularly its preference for invading the Schwann cells localized at the coldest areas of human body, we hypothesized that these areas have focal demyelination that may escape detection through standard nerve conduction studies (NCSs) protocols. Twenty-five patients with confirmed multibacillary leprosy and 14 controls were accessed. A multisegmented NCS protocol (MP) was performed, targeting short segments through the coldest areas, to identify focal areas of slowed conduction velocity. The effectiveness of this multisegmented protocol was compared to the standard protocol (SP) to detect abnormalities. All leprosy patients presented an abnormal study with the MP, contrasting to 19 with the SP. The most frequent NCS pattern was an asymmetric neuropathy with focal slowing of conduction velocity, found in 23 out of 25 leprosy patients. Significant differences favoring the proposed method were observed when comparing the MP with the SP. Notably, the MP increased the sensitivity to detect abnormalities by 122%, 133%, and 257% for the median, peroneal, and tibial nerves, respectively. MP also increases sensitivity to detect focal abnormalities in the ulnar nerve. The MP protocol significantly increases the sensitivity of NCSs to detect neurophysiological abnormalities in leprosy neuropathy.

Deferiprone promoted remyelination and functional recovery through enhancement of oligodendrogenesis in experimental demyelination animal model.

Remyelination refers to myelin regeneration, which reestablishes metabolic supports to axons. However, remyelination often fails in multiple sclerosis (MS), leading to chronic demyelination and axonal degeneration. Therefore, pharmacological approaches toward enhanced remyelination are highly demanded. Recently, deferiprone (DFP) was reported to exert neuroprotective effects, besides its iron-chelating ability. Since DFP exerts protective effects through various mechanisms, which share several factors with myelin formation process, we aimed to investigate the effects of DFP treatment on remyelination. Focal demyelination was induced by injection of lysolecithin, into the optic nerve of male C57BL/6J mice. The animals were treated with DFP/vehicle, starting from day 7 and continued during the myelin repair period. Histopathological, electrophysiological, and behavioral studies were used to evaluate the outcomes. Results showed that DFP treatment enhanced remyelination, decreased g-ratio and increased myelin thickness. At the mechanistic level, DFP enhanced oligodendrogenesis and ameliorated gliosis during the remyelination period. Furthermore, our results indicated that enhanced remyelination led to functional recovery as evaluated by the electrophysiological and behavioral tests. Even though the exact molecular mechanisms by which DFP-enhanced myelin repair remain to be elucidated, these results raise the possibility of using deferiprone as a therapeutic agent for remyelination therapy in MS.

Exploring the Clinical Impact of Magnetite Nanoparticles in a Multifaceted Approach to Treating Multiple Sclerosis

Multiple sclerosis (MS) is a serious neurological disorder due to its widespread prevalence, chronic nature, frequent progression to disability, and tendency to affect young people. The pathogenesis of MS is based on the immunopathogenesis hypothesis. Biocompatible magnetite nanoparticles, which exhibit selective sorption activity towards cell membrane surface proteins, circulating immune complexes, lymphocytotoxic antibodies, and the complement system, as well as enhance phagocytic activity and the completion index of leukocyte phagocytosis, can be effectively used for immunocorrection. The main goal of the study is to slow the progression of MS, improve the neurological status and overall condition of the patient, and reduce the dynamics of the spread of demyelinating lesions in the brain. Materials and methods: A patient diagnosed with multiple sclerosis, secondary progressive type, cerebrospinal form, at the clinical aggravation stage was included in the study. Neurological status and disability were assessed using the EDSS scale, and brain MRI with contrast enhancement was performed. The nanodevice Micromage-B was administered orally as an immunosorbent and immunomodulator. The regimen and dosage of Micromage-B were personalized. Assessments of general condition and neurological status were conducted every 7 days for 6 months, with contrast-enhanced brain MRI performed in the 5th month. Results: The use of Micromage-B in MS treatment led to an objective improvement in neurological status, with reduced stiffness and fatigue in the lower extremities. Gait and coordination improved, hand tremors decreased, depression and concentration disorders subsided, appetite was restored, and speech improved. Throughout the treatment period, positive dynamics in the normalization of neurological status were observed. After 6 months, the total score on the EDSS scale decreased from 210 to 45. The most significant improvements were observed in the evaluation of the pyramidal system and coordination, with the EDSS Disability Scale score decreasing from 6.0 to 5.0. For the first time, contrast-enhanced brain MRI showed a reduction in the number of new demyelination foci by the 4th month of Micromage-B administration. The positive changes in neurological status correlated with the MRI results. The recovery of central nervous system activity in MS is likely not only due to the immunosuppressive properties of magnetite nanoparticles but also due to the activation of remyelination mechanisms and oligodendrocyte differentiation through enzymatic methylation. Conclusion: The use of biocompatible nanodevices in the complex treatment of MS is promising. Further improvement and study of the regimen and method of using biocompatible magnetite nanoparticles to enhance MS treatment effectiveness are required.

Effective Application of Biocompatible Magnetite Nanoparticles in the Treatment of Multiple Sclerosis: Results of a Clinical Study

Multiple sclerosis (MS) is a serious neurological disorder due to its widespread prevalence, chronic nature, frequent progression to disability, and tendency to affect young people. The pathogenesis of MS is based on the immunopathogenesis hypothesis. Biocompatible magnetite nanoparticles, which exhibit selective sorption activity towards cell membrane surface proteins, circulating immune com-plexes, lymphocytotoxic antibodies, and the complement system, as well as enhance phagocytic ac-tivity and the completion index of leukocyte phagocytosis, can be effectively used for immunocor-rection. The main goal of the study is to slow the progression of MS, improve the neurological status and overall condition of the patient, and reduce the dynamics of the spread of demyelinating lesions in the brain. Materials and methods: A patient diagnosed with multiple sclerosis, secondary progres-sive type, cerebrospinal form, at the clinical aggravation stage was included in the study. Neurologi-cal status and disability were assessed using the EDSS scale, and brain MRI with contrast enhance-ment was performed. The nanodevice Micromage-B was administered orally as an immunosorbent and immunomodulator. The regimen and dosage of Micromage-B were personalized. Assessments of general condition and neurological status were conducted every 7 days for 6 months, with contrast-enhanced brain MRI performed in the 5th month. Results: The use of Micromage-B in MS treatment led to an objective improvement in neurological status, with reduced stiffness and fatigue in the lower extremities. Gait and coordination improved, hand tremors decreased, depression and concen-tration disorders subsided, appetite was restored, and speech improved. Throughout the treatment period, positive dynamics in the normalization of neurological status were observed. After 6 months, the total score on the EDSS scale decreased from 210 to 45. The most significant improvements were observed in the evaluation of the pyramidal system and coordination, with the EDSS Disability Scale score decreasing from 6.0 to 5.0. For the first time, contrast-enhanced brain MRI showed a reduction in the number of new demyelination foci by the 4th month of Micromage-B administra-tion. The positive changes in neurological status correlated with the MRI results. The recovery of central nervous system activity in MS is likely not only due to the immunosuppressive properties of magnetite nanoparticles but also due to the activation of remyelination mechanisms and oligoden-drocyte differentiation through enzymatic methylation. Conclusion: The use of biocompatible nanodevices in the complex treatment of MS is promising. Further improvement and study of the regimen and method of using biocompatible magnetite nanoparticles to enhance MS treatment effec-tiveness are required.

Trametinib, an anti-tumor drug, promotes oligodendrocytes generation and myelin formation.

Oligodendrocytes (OLs) are differentiated from oligodendrocyte precursor cells (OPCs) in the central nervous system (CNS). Demyelination is a common feature of many neurological diseases such as multiple sclerosis (MS) and leukodystrophies. Although spontaneous remyelination can happen after myelin injury, nevertheless, it is often insufficient and may lead to aggravated neurodegeneration and neurological disabilities. Our previous study has discovered that MEK/ERK pathway negatively regulates OPC-to-OL differentiation and remyelination in mouse models. To facilitate possible clinical evaluation, here we investigate several MEK inhibitors which have been approved by FDA for cancer therapies in both mouse and human OPC-to-OL differentiation systems. Trametinib, the first FDA approved MEK inhibitor, displays thebest effect in stimulating OL generation in vitro among the four MEK inhibitors examined. Trametinib also significantly enhances remyelination in both MOG-induced EAE model and LPC-induced focal demyelination model. More exciting, trametinib facilitates the generation of MBP+ OLs from human embryonic stem cells (ESCs)-derived OPCs. Mechanism study indicates that trametinib promotes OL generation by reducing E2F1 nuclear translocation and subsequent transcriptional activity. In summary, our studies indicate a similar inhibitory role of MEK/ERK in human and mouse OL generation. Targeting the MEK/ERK pathway might help to develop new therapies or repurpose existing drugs for demyelinating diseases.

Trigeminal neuralgia.

Trigeminal neuralgia (TN) is a facial pain disorder characterized by intense and paroxysmal pain that profoundly affects quality of life and presents complex challenges in diagnosis and treatment. TN can be categorized as classical, secondary and idiopathic. Epidemiological studies show variable incidence rates and an increased prevalence in women and in the elderly, with familial cases suggesting genetic factors. The pathophysiology of TN is multifactorial and involves genetic predisposition, anatomical changes, and neurophysiological factors, leading to hyperexcitable neuronal states, central sensitization and widespread neural plasticity changes. Neurovascular compression of the trigeminal root, which undergoes major morphological changes, and focal demyelination of primary trigeminal afferents are key aetiological factors in TN. Structural and functional brain imaging studies in patients with TN demonstrated abnormalities in brain regions responsible for pain modulation and emotional processing of pain. Treatment of TN involves a multifaceted approach that considers patient-specific factors, including the type of TN, with initial pharmacotherapy followed by surgical options if necessary. First-line pharmacological treatments include carbamazepine and oxcarbazepine. Surgical interventions, including microvascular decompression and percutaneous neuroablative procedures, can be considered at an early stage if pharmacotherapy is not sufficient for pain control or has intolerable adverse effects or contraindications.

Presenile dementia concomitant with Sjogren's syndrome：A Case Report

What etiology would you think of apart from classic degenerative cause for a dementia lady to make a diagnosis of AD at her age of 58? It has been reported that a 65-year-old female had got declining speech for the past seven years，concomitant with “rampant caries”in her mouth and “vitiligo”on her skin. She was also allergic to penicillin，together with an abnormal subpopulation of lymphocytes (TBNK) and multiple foci of demyelination seen on her brain CT （limbic system). Finally，a diagnosis of presenile dementia resulting from Sjogren's syndrome was established for this lady，suggesting that the autoimmunity mechanism may be involved in the pathogenesis of presenile dementia in a relatively young person.

β-carbolines that enhance GABAA receptor response expressed in oligodendrocytes promote remyelination in an in vivo rat model of focal demyelination.

Demyelination is typically followed by a remyelination process through mature oligodendrocytes (OLs) differentiated from precursor cells (OPCs) recruited into the lesioned areas, however, this event usually results in uncompleted myelination. Potentiation of the remyelination process is an important target for designing effective therapeutic strategies against white matter loss. Here, it was evaluated the remyelinating effect of different β-carbolines that present differential allosteric modulation on the GABAA receptor expressed in OLs. For this, we used a focalized demyelination model in the inferior cerebellar peduncle (i.c.p.) of rats (DRICP model), in which, demyelination by ethidium bromide (0.05%) stereotaxic injection was confirmed histologically by staining with Black-Gold II (BGII) and toluidine blue. In addition, a longitudinal analysis with diffusion-weighted magnetic resonance imaging (dMRI) was made by computing fractional anisotropy (FA), apparent diffusion coefficient (ADC) and diffusivity parameters to infer i.c.p. microstructural changes. First, dMRI analysis revealed FA decreases together with ADC and radial diffusivity (RD) increases after demyelination, which correlates with histological BGII observations. Then, we evaluated the effect produced by three allosteric GABAA receptor modulators, the N-butyl-β-carboline-3-carboxylate (β-CCB), ethyl 9H-pyrido [3,4-b]indole-3-carboxylate (β-CCE), and 4-ethyl-6,7-dimethoxy-9H-pyrido [3,4-b]indole-3-carboxylic acid methyl ester (DMCM). The results indicated that daily systemic β-CCB (1 mg/Kg) or β-CCE (1 mg/Kg) administration for 2 weeks, but not DMCM (0.35 mg/Kg), in lesioned animals increased FA and decreased ADC or RD, suggesting myelination improvement. This was supported by BGII staining analysis that showed a recovery of myelin content. Also, it was quantified by immunohistochemistry both NG2+ and CC1+ cellular population in the different experimental sceneries. Data indicated that either β-CCB or β-CCE, but not DMCM, produced an increase in the population of CC1+ cells in the lesioned area. Finally, it was also calculated the g-ratio of myelinated axons and observed a similar value in those lesioned animals treated with β-CCB or β-CCE compared to controls. Thus, using the DRICP model, it was observed that either β-CCB or β-CCE, positive modulators of the GABAA receptor in OLs, had a potent promyelinating effect.

Application of a computer vision algorithm to identify foci of demyelination in multiple sclerosis on MRI images

The research was aimed at analyzing modern algorithms for diagnosing lesions in multiple sclerosis on MRI images. Multiple sclerosis is a severe disease of the central nervous system and ranks first among the causes of disability in patients of young working age. In connection with the development of computer vision and machine learning technologies, the relevance of using these technologies for medical diagnostics is growing. Such approaches are necessary for the effective development and implementation of diagnostic systems using artificial intelligence. Modern algorithms and models for lesion segmentation were selected and implemented. Material and methods. The paper presents CV features of diagnosing multiple sclerosis on MRI images, existing data sets: ISBI-2015, MSSEG-2016, MSSEG-2021; existing algorithms and models for lesion segmentation: U-Net, nnU-Net, TransUnet, TransBTS, UNETR, Swin UNETR. Results and discussion. The architectures and models of nnU-Net, UNETR, Swin UNETR were trained and compared at ISBI2015 with various parameters and loss functions. Four MRI sequences were used: T2-WI, T2-FLAIR, PD, MPRAGE. Lesion segmentation was approved by certified experienced neuroradiologists. Conclusions. The approaches described in the paper including data processing, model training, and results analysis, focused on the selection and development of high-quality computer vision algorithms for identifying multiple sclerosis lesions in MRI images. Identification and segmentation of demyelination foci is a necessary step for diagnosing the disease, as well as for calculating and interpreting more meaningful indicators of disease severity and progression.

Value of MUNE versus compound muscle action potential in assessing motor unit loss in patients with carpal tunnel syndrome

BackgroundThe most prevalent nerve entrapment disorder, known as carpal tunnel syndrome (CTS), is brought on by wrist-based median nerve compression. Focal demyelination progresses to axonal dysfunction as the condition worsens. In order to detect motor unit (MU) loos, this study compares two motor unit number estimation (MUNE) techniques with compound muscle action potential (CMAP) amplitude. The CMAP amplitude and MUNE of the median nerve in 137 hands of 70 neurophysiologically approved CTS patients, aged 40.27 ± 10.06 years were examined. Another 90 hands from 56 healthy volunteers who are age- and gender-matched serve the control group.ResultsIn contrast to 192.5 and 248.5 in controls, the median nerve values of incremental and adapted multipoint stimulation (aMPS) MUNE in CTS patients were, respectively, 111 and 133 (p < 0.0001). Patients with severe CTS compared to those with mild CTS using both methods had significantly lower MUNE. MUNE values are the same regardless of gender or hand dominance. In comparison to MUNE methods (cutoff values of 106.5 and 203, respectively), CMAP amplitude had a sensitivity and specificity of more than 60% in detecting MU loss (cutoff value of 6.85 mV). The CTS grading had no effect on the CMAP amplitude. MUNE values had positive with CMAP amplitude and negative with CTS grading and Phalen test positivity.ConclusionsWhen identifying motor nerve involvement in CTS patients, the MUNE technique is more accurate than a standard motor nerve conduction study (NCS). It was emphasized that MUNE evaluation in determining MU loss in the early stages of CTS may be helpful in diagnosis and treatment. There was no correlation between handedness and the number of MUs as determined by MUNE techniques. Both methods almost equally identify MU loss and have the same sensitivity and specificity.

Characteristics, Prevalence, and Clinical Relevance of Juxtacortical Paramagnetic Rims in Patients With Multiple Sclerosis.

A subgroup of patients with multiple sclerosis (MS) presents focal paramagnetic rims at the border between cortex and white matter (juxtacortical paramagnetic rims [JPRs]). We investigated the presence of this finding in our in vivo MS cohort and explored its potential clinical relevance. Moreover, we exploited postmortem MRI of fixed whole MS brains to (1) detect those rims and (2) investigate their histologic correlation. Quantitative susceptibility mapping (QSM) and magnetization-prepared 2 rapid acquisition gradient-echo (MP2RAGE) images at 3T-MRI of 165 patients with MS from the in vivo cohort were screened for JPRs and the presence of cortical lesions. Five postmortem brains from patients with MS were imaged with 3T-MRI to obtain QSM and MP2RAGE sequences. Tissue blocks containing JPRs were excised and paraffin-embedded slices stained by immunohistochemistry for myelin basic protein (for myelin) and anti-CR3/43 (for major histocompatibility complex II-positive microglia/macrophages). DAB-Turnbull stain was performed to detect iron. JPRs are present in approximately 10% of in vivo patients and are associated with increased cortical lesion load. One of the 5 postmortem brains showed JPRs. Histologically, JPRs correspond to an accumulation of activated iron-laden phagocytes and are associated with demyelination of the whole overlying cortical ribbon. JPRs are a novel potential MRI biomarker of focal cortical demyelination, which seems related to global cortical pathology and might be useful for diagnostic and stratification purposes in a clinical setting.

Interplay between androgen and CXCR4 chemokine signaling in myelin repair

In men, reduced levels of testosterone are associated with the prevalence and progression of multiple sclerosis (MS), a chronic and disabling demyelinating disorder. Testosterone has been shown to promote myelin repair. Here, we demonstrate that the cooperation between testosterone and CXCR4 signaling involving astrocytes is required for myelin regeneration after focal demyelination produced in the ventral mouse spinal cord by the infusion of lysolecithin. The testosterone-dependent remyelination of axons by oligodendrocytes was accompanied by an increase in astrocytes expressing CXCR4, its ligand CXCL12 and the androgen receptor (AR) within the demyelinated area. Depriving males of their testosterone or pharmacological inhibition of CXCR4, with the selective antagonist AMD3100, prevented the appearance of astrocytes expressing CXCR4, CXCL12 and AR within the demyelinated area and the concomitant recruitment of myelin forming oligodendrocytes. Conditional genetic ablation of either CXCR4 or AR in astrocytes also completely blocked the formation of new myelin by oligodendrocytes. Interestingly, the gain of function mutation in CXCR4 causing WHIM syndrome allows remyelination to take place, even in the absence of testosterone, but its potentiating effects remained observable. After testosterone deprivation or CXCR4 inhibition, the absence of astrocytes within the demyelinated area led to the incursion of Schwann cells, most likely derived from spinal nerves, and the formation of peripheral nerve type myelin. In patients with progressive MS, astrocytes expressing CXCR4 and AR surrounded myelin lesions, and their presence opposed the incursion of Schwann cells. These results highlight a mechanism of promyelinating testosterone signaling and the importance of normalizing its levels in combined myelin repair therapies.

Osmotic demyelinating syndrome and its manifestations

Osmotic demyelination syndrome (ODS) is a rare and severe dysmetabolic lesion of the central nervous system which is difficult to diagnose. Its prevalence in the general population reaches 0.5 %, and in intensive care nits — 2.5 %. Within the framework of ODS, central pontine myelinolysis with demyelination of the pons and extrapontine myelinolysis with foci of demyelination in the cerebellum and cerebral hemispheres are distinguished. Clinical cases of ODS that developed against the background of dehydration are presented