Infiltration by monocytes of the central nervous system and its role in multiple sclerosis: reflections on therapeutic strategies

Mononuclear macrophage infiltration in the central nervous system is a prominent feature of neuroinflammation. Recent studies on the pathogenesis and progression of multiple sclerosis have highlighted the multiple roles of mononuclear macrophages in the neuroinflammatory process. Monocytes play a significant role in neuroinflammation, and managing neuroinflammation by manipulating peripheral monocytes stands out as an effective strategy for the treatment of multiple sclerosis, leading to improved patient outcomes. This review outlines the steps involved in the entry of myeloid monocytes into the central nervous system that are targets for effective intervention: the activation of bone marrow hematopoiesis, migration of monocytes in the blood, and penetration of the blood–brain barrier by monocytes. Finally, we summarize the different monocyte subpopulations and their effects on the central nervous system based on phenotypic differences. As activated microglia resemble monocyte-derived macrophages, it is important to accurately identify the role of monocyte-derived macrophages in disease. Depending on the roles played by monocyte-derived macrophages at different stages of the disease, several of these processes can be interrupted to limit neuroinflammation and improve patient prognosis. Here, we discuss possible strategies to target monocytes in neurological diseases, focusing on three key aspects of monocyte infiltration into the central nervous system, to provide new ideas for the treatment of neurodegenerative diseases.

Multiple sclerosis is at a checkpoint: advancing the program

Multiple sclerosis(MS) is a chronic inflammatory and demyelinating disease of the central nervous system(CNS). Patients with MS experience sensory and motor function loss due to myelin and/or axon damage perpetuated by infiltrating immune cells(Hauser and Cree, 2020).

Gut flora in multiple sclerosis:implications for pathogenesis and treatment

Multiple sclerosis is an inflammatory disorder chara cterized by inflammation,demyelination,and neurodegeneration in the central nervous system.Although current first-line therapies can help manage symptoms and slow down disease progression,there is no cure for multiple sclerosis.The gut-brain axis refers to complex communications between the gut flo ra and the immune,nervous,and endocrine systems,which bridges the functions of the gut and the brain.Disruptions in the gut flora,termed dys biosis,can lead to systemic inflammation,leaky gut syndrome,and increased susceptibility to infections.The pathogenesis of multiple sclerosis involves a combination of genetic and environmental factors,and gut flora may play a pivotal role in regulating immune responses related to multiple scle rosis.To develop more effective therapies for multiple scle rosis,we should further uncover the disease processes involved in multiple sclerosis and gain a better understanding of the gut-brain axis.This review provides an overview of the role of the gut flora in multiple scle rosis.

Physical exercise and synaptic protection in human and pre-clinical models of multiple sclerosis

In multiple sclerosis,only immunomodulato ry and immunosuppressive drugs are recognized as disease-modifying therapies.Howeve r,in recent years,several data from pre-clinical and clinical studies suggested a possible role of physical exe rcise as disease-modifying therapy in multiple sclerosis.Current evidence is sparse and often conflicting,and the mechanisms underlying the neuroprotective and antinflammatory role of exercise in multiple sclerosis have not been fully elucidated.Data,mainly derived from pre-clinical studies,suggest that exe rcise could enhance longterm potentiation and thus neuroplasticity,could reduce neuroinflammation and synaptopathy,and dampen astrogliosis and microgliosis.In humans,most trials focused on direct clinical and MRI outcomes,as investigating synaptic,neuroinflammato ry,and pathological changes is not straightfo rward compared to animal models.The present review analyzed current evidence and limitations in research concerning the potential disease-modifying therapy effects of exercise in multiple sclerosis in animal models and human studies.

Unraveling the potential of acute intermittent hypoxia as a strategy for inducing robust repair in multiple sclerosis

Multiple sclerosis(MS)is a debilitating inflammatory disease of the central nervous system characterized by immune-mediated segmental demyelination and variable degrees of axonal and neuronal degeneration that contribute to disability.Inducing efficient and effective repair programs following demyelination is a major goal and challenge in MS.Conventional MS therapies focus largely on modulating the immune aspects of the disease contributing to lesions.While this alleviates some symptoms and mitigates damage,it does not tackle the fundamental challenge of effective remyelination,which few MS patients experience,especially in the progressive phase of the disease.

Assistive techniques and their added value for tremor classification in multiple sclerosis

Tremor occurs in about half of multiple sclerosis(MS)patients.MS tremor has a broad frequency range of 2.5-7 Hz,with a higher prevalence of postural tremor(44%)compared to intentional tremor(6%)(Alusi et al.,2001).Tremor may affect the upper and lower extremities,head,and trunk,and may even affect the vocal cords in isolated cases of palatal tremor.MS tremor is classically attributed to lesions of the brain stem,cerebellum,or cerebellar peduncles,and tremor intensity has been shown to correlate with the number of lesions or their functional connections.However,recent work has demonstrated that inflammatory damage to the cerebello-thalamic and cortico-thalamic pathways might also play an important role in causing tremor,as it co-occurs with other signs and symptoms of MS such as dysarthria,dysmetria,dysdiadochokinesia,and dystonia(Alusi et al.,2001).

Examination of the Effective Factors on the Multiple Sclerosis Diseases

This study was an attempt to examine the effective factors of the Multiple Sclerosis diseases. The participants of the study were selected from among a total number of 45 men and women who were treated in a health center in Azarbayegan and Damavand in Iran. In order to study, the researchers applied various procedures to collect the data of the study. The participants were interviewed and filled out the questionnaires. After categorizing and classifying the collected information and data, it was processed and analyzed and the results are found. To test the research questions, a one-sample T-test was used to analyze the data. The role of hypo vitamin D as a possible risk factor for multiple sclerosis was reviewed. First, it was emphasized that hypo vitamin could be only one of the risk factors for multiple sclerosis and that numerous other environmental and genetic risk factors appear to interact and combine to trigger the disease. The main aim of this study was to examine the effective factors of Multiple Sclerosis diseases. The methodology of this research was to test the research questions;one-sample T-test was used to analyze the data. The findings of this study revealed that the factors of gender, cold weather, vitamin D deficiency, and age (between 30 - 59) were effective on the Multiple Sclerosis diseases.

Immunologic pathogenesis of multiple sclerosis

Multiple sclerosis （MS） is an autoimmune disease. The etiology and pathogenesis of MS remain unclear. At present, there are substantial evidences to support the hypothesis that genetics plays a crucial role. The people who have genetic predisposing genes easily develop immune-mediated disorder, probably in conjunction with environmental factors. The aim of this review is to describe recent observations regarding the immunologic pathogenesis of MS.

Beginning from the end:the presynaptic terminal as a pathomechanism hub in frontotemporal dementia and amyotrophic lateral sclerosis

Frontotemporal dementia and amyotrophic lateral sclerosis:Frontotemporal dementia(F T D)and amyo t rophic lateral sclerosis(ALS)are neurodegenerative diseases with significant overlapping attributes.While these neurodegenerative diseases affect different neuronal populations(with FTD affecting neurons of the frontal and temporal lobes,and ALS affecting upper and lower motor neurons),these two diseases are complexly intertwined.FTD and ALS exist on a disease spectrum,with shared genetic causes,clinical presentations,and pathologies.

Carboplatin restores neuronal toxicity in FUS-linked amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis(ALS),also known as Lou Geh rig's disease,is a progressive neurodegenerative disorder that affects motor neurons in the brain and spinal cord.This leads to muscle weakness,paralysis,and ultimately,respiratory failure(Cha and Kim,2022).

Biochemical dissection of STAT3 signaling in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis(ALS)is a progressive neurodegenerative disease characterized by the loss of upper and lower motor neurons,clinically marked by muscle atrophy and weakness.Although the clinical course is highly variable,the average time from the onset of symptoms to the need for respiratory support or death is 3-5 years.ALS is the most prevalent motor neuron disease in adults,occurring at a rate of 2 per 100,000 individuals and affecting 5.4 per 100,000 individuals overall.

Disruption of neuronal actin barrier promotes the entry of disease-implicated proteins to exacerbate amyotrophic lateral sclerosis pathology

Amyotrophic lateral sclerosis(ALS)is a devastating neurological disease characterized by the accumulation of aberrant proteins in motor neurons of the brain and spinal cord.Patients with ALS develop skeletal muscle weakness,resulting in death from respiratory paralysis,which usually occurs 2-4 years after clinical onset(Goutman et al.,2022).

Small extrachromosomal circular DNA in amyotrophic lateral sclerosis matter

Comprehensive studies identify motor neuron spectrum disorders including amyotrophic lateral sclerosis(ALS)as globally rising fatal disorders with the highest prevalence in aging populations,influenced by ethnicity and ancestry(GBD 2016 Motor Neuron Disease Colla borators,2018).While~10% of diagnoses involve a family history(fALS),most cases are considered sporadic(sALS).However,population-based studies suggest that even cases without a common index mutation impart heritability(Ryan et al.,2019),indicating a crucial role of rare and as yet unknown genetic denominators.

Translational challenges in amyotrophic lateral sclerosis therapy with macrophage migration inhibitory factor

Macrophage migration inhibitory factor(MIF):MIF acts as a pleiotropic inflammatory mediator,playing regulatory roles in innate and adaptive immunity,neuroinflammation,neuroendocrine functions,and nervous system development(Matejuk et al.,2024).In recent years,MIF has attra cted significant inte rest from research groups as a potential target for the treatment of various neurodegenerative diseases,including Alzheimer's disease,Parkinson's disease,multiple sclerosis,and glioblastoma(Matejuk et al.,2024).

Treating amyotrophic lateral sclerosis with allogeneic Schwann cell-derived exosomal vesicles: a case report

Schwann cells are essential for the maintenance and function of motor neurons,axonal networks,and the neuromuscular junction.In amyotrophic lateral sclerosis,where motor neuron function is progressively lost,Schwann cell function may also be impaired.Recently,important signaling and potential trophic activities of Schwann cell-derived exosomal vesicles have been reported.This case report describes the treatment of a patient with advanced amyotrophic lateral sclerosis using serial intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles,marking,to our knowledge,the first instance of such treatment.An 81-year-old male patient presented with a 1.5-year history of rapidly progressive amyotrophic lateral sclerosis.After initial diagnosis,the patient underwent a combination of generic riluzole,sodium phenylbutyrate for the treatment of amyotrophic lateral sclerosis,and taurursodiol.The patient volunteered to participate in an FDA-approved single-patient expanded access treatment and received weekly intravenous infusions of allogeneic Schwann cell-derived exosomal vesicles to potentially restore impaired Schwann cell and motor neuron function.We confirmed that cultured Schwann cells obtained from the amyotrophic lateral sclerosis patient via sural nerve biopsy appeared impaired(senescent)and that exposure of the patient’s Schwann cells to allogeneic Schwann cell-derived exosomal vesicles,cultured expanded from a cadaver donor improved their growth capacity in vitro.After a period of observation lasting 10 weeks,during which amyotrophic lateral sclerosis Functional Rating Scale-Revised and pulmonary function were regularly monitored,the patient received weekly consecutive infusions of 1.54×1012(×2),and then consecutive infusions of 7.5×1012(×6)allogeneic Schwann cell-derived exosomal vesicles diluted in 40 mL of Dulbecco’s phosphate-buffered saline.None of the infusions were associated with adverse events such as infusion reactions(allergic or otherwise)or changes in vital signs.Clinical lab serum neurofilament and cytokine levels measured prior to each infusion varied somewhat without a clear trend.A more sensitive in-house assay suggested possible inflammasome activation during the disease course.A trend for clinical stabilization was observed during the infusion period.Our study provides a novel approach to address impaired Schwann cells and possibly motor neuron function in patients with amyotrophic lateral sclerosis using allogeneic Schwann cell-derived exosomal vesicles.Initial findings suggest that this approach is safe.

Is autoimmunity in multiple sclerosis secondary to neurodegeneration？

Multiple sclerosis （MS） is characterized by neurological symptoms that are separated in time and space, which correlate with demyelination and white matter lesions. The conventional pathophysiological model is that an autoimmune reaction against the myelinated nerve sheath results in demyelination, accompanied by axon damage and the death of oligodendrocytes that produce myelin. There is no cure for MS, but current treatments are pr imar i ly aimed at suppressing the autoimmune reaction, with the goal of reducing demyelination. These treatments have limited efficacy and developing better treatments for MS remains an important goal. Here we argue that the autoimmune reaction may be secondary to neurodegeneration or neurotoxicity, and that protecting neurons from glutamate-mediated toxicity may be a better therapeutic strategy than targeting the immune system. We have recently demonstrated that a protein-protein interaction between the GluR2 subunit of the AMPA （a-Amino-3-hydroxy-5-methyl-4- isoxazolepropionic acid） glutamate receptor and GAPDH （Glyceraldehyde 3-phosphate dehydrogenase） is elevated in human MS plaques and in an animal model of MS. Disrupting this interaction in a rodent model restores neurological function, preserves myelin, and protects neurons, oligodendrocytes and axons. The peptide we created to block the GluR2-GAPDH interaction also reduces immune system activation, suggesting that autoimmunity is not necessarily the primary etiology in MS. The GluR2-GAPDH interaction may promote cell death via increased calcium influx through non-GluR2- containing AMPA receptors, or through the p53 and Siahl cell death pathways.

Blood diagnostic and prognostic biomarkers in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a devastating neurodegenerative disease for which the current treatment approaches remain severely limited.The principal pathological alterations of the disease include the selective degeneration of motor neurons in the brain,brainstem,and spinal cord,as well as abnormal protein deposition in the cytoplasm of neurons and glial cells.The biological markers under extensive scrutiny are predominantly located in the cerebrospinal fluid,blood,and even urine.Among these biomarke rs,neurofilament proteins and glial fibrillary acidic protein most accurately reflect the pathologic changes in the central nervous system,while creatinine and creatine kinase mainly indicate pathological alterations in the peripheral nerves and muscles.Neurofilament light chain levels serve as an indicator of neuronal axonal injury that remain stable throughout disease progression and are a promising diagnostic and prognostic biomarker with high specificity and sensitivity.However,there are challenges in using neurofilament light chain to diffe rentiate amyotrophic lateral sclerosis from other central nervous system diseases with axonal injury.Glial fibrillary acidic protein predominantly reflects the degree of neuronal demyelination and is linked to non-motor symptoms of amyotrophic lateral sclerosis such as cognitive impairment,oxygen saturation,and the glomerular filtration rate.TAR DNA-binding protein 43,a pathological protein associated with amyotrophic lateral sclerosis,is emerging as a promising biomarker,particularly with advancements in exosome-related research.Evidence is currently lacking for the value of creatinine and creatine kinase as diagnostic markers;however,they show potential in predicting disease prognosis.Despite the vigorous progress made in the identification of amyotrophic lateral sclerosis biomarkers in recent years,the quest for definitive diagnostic and prognostic biomarke rs remains a formidable challenge.This review summarizes the latest research achievements concerning blood biomarkers in amyotrophic lateral sclerosis that can provide a more direct basis for the differential diagnosis and prognostic assessment of the disease beyond a reliance on clinical manifestations and electromyography findings.

The burden of upper motor neuron involvement is correlated with the bilateral limb involvement interval in patients with amyotrophic lateral sclerosis:a retrospective observational study

Amyotrophic lateral sclerosis is a rare neurodegenerative disease characterized by the involvement of both upper and lower motor neurons.Early bilateral limb involvement significantly affects patients'daily lives and may lead them to be confined to bed.However,the effect of upper and lower motor neuron impairment and other risk factors on bilateral limb involvement is unclear.To address this issue,we retrospectively collected data from 586 amyotrophic lateral sclerosis patients with limb onset diagnosed at Peking University Third Hospital between January 2020 and May 2022.A univariate analysis revealed no significant differences in the time intervals of spread in different directions between individuals with upper motor neuron-dominant amyotrophic lateral sclerosis and those with classic amyotrophic lateral sclerosis.We used causal directed acyclic graphs for risk factor determination and Cox proportional hazards models to investigate the association between the duration of bilateral limb involvement and clinical baseline characteristics in amyotrophic lateral sclerosis patients.Multiple factor analyses revealed that higher upper motor neuron scores(hazard ratio[HR]=1.05,95%confidence interval[CI]=1.01–1.09,P=0.018),onset in the left limb(HR=0.72,95%CI=0.58–0.89,P=0.002),and a horizontal pattern of progression(HR=0.46,95%CI=0.37–0.58,P<0.001)were risk factors for a shorter interval until bilateral limb involvement.The results demonstrated that a greater degree of upper motor neuron involvement might cause contralateral limb involvement to progress more quickly in limb-onset amyotrophic lateral sclerosis patients.These findings may improve the management of amyotrophic lateral sclerosis patients with limb onset and the prediction of patient prognosis.

Multifaceted superoxide dismutase 1 expression in amyotrophic lateral sclerosis patients:a rare occurrence?

Amyotrophic lateral sclerosis(ALS)is a neuromuscular condition resulting from the progressive degeneration of motor neurons in the cortex,brainstem,and spinal cord.While the typical clinical phenotype of ALS involves both upper and lower motor neurons,human and animal studies over the years have highlighted the potential spread to other motor and non-motor regions,expanding the phenotype of ALS.Although superoxide dismutase 1(SOD1)mutations represent a minority of ALS cases,the SOD1 gene remains a milestone in ALS research as it represents the first genetic target for personalized therapies.Despite numerous single case reports or case series exhibiting extramotor symptoms in patients with ALS mutations in SOD1(SOD1-ALS),no studies have comprehensively explored the full spectrum of extramotor neurological manifestations in this subpopulation.In this narrative review,we analyze and discuss the available literature on extrapyramidal and non-motor features during SOD1-ALS.The multifaceted expression of SOD1 could deepen our understanding of the pathogenic mechanisms,pointing towards a multidisciplinary approach for affected patients in light of new therapeutic strategies for SOD1-ALS.

Neurogenic bowel dysfunction in patients with spinal cord injury, myelomeningocele, multiple sclerosis and Parkinson’s disease

Exciting new features have been described concerning neurogenic bowel dysfunction,including interactions between the central nervous system,the enteric nervous system,axonal injury,neuronal loss,neurotransmission of noxious and non-noxious stimuli,and the fields of gastroenterology and neurology.Patients with spinal cord injury,myelomeningocele,multiple sclerosis and Parkinson's disease present with serious upper and lower bowel dysfunctions characterized by constipation,incontinence,gastrointestinal motor dysfunction and altered visceral sensitivity.Spinal cord injury is associated with severe autonomic dysfunction,and bowel dysfunction is a major physical and psychological burden for these patients.An adult myelomeningocele patient commonly has multiple problems reflecting the multisystemic nature of the disease.Multiple sclerosis is a neurodegenerative disorder in which axonal injury,neuronal loss,and atrophy of the central nervous system can lead to permanent neurological damage and clinical disability.Parkinson's disease is a multisystem disorder involving dopaminergic,noradrenergic,serotoninergic and cholinergic systems,characterizedby motor and non-motor symptoms.Parkinson's disease affects several neuronal structures outside the substantia nigra,among which is the enteric nervous system.Recent reports have shown that the lesions in the enteric nervous system occur in very early stages of the disease,even before the involvement of the central nervous system.This has led to the postulation that the enteric nervous system could be critical in the pathophysiology of Parkinson's disease,as it could represent the point of entry for a putative environmental factor to initiate the pathological process.This review covers the data related to the etiology,epidemiology,clinical expression,pathophysiology,genetic aspects,gastrointestinal motor dysfunction,visceral sensitivity,management,prevention and prognosis of neurogenic bowel dysfunction patients with these neurological diseases.Embryological,morphological and experimental studies on animal models and humans are also taken into account.