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.

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.

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.

Microglia depletion as a therapeutic strategy:friend or foe in multiple sclerosis models?

M ultiple sclerosis is a chro nic central nervous system demyelinating disease whose onset and progression are driven by a combination of immune dysregulation,genetic predisposition,and environmental fa ctors.The activation of microglia and astrocytes is a key player in multiple sclerosis immunopathology,playing specific roles associated with anatomical location and phase of the disease and controlling demyelination and neurodegeneration.Even though reactive mic roglia can damage tissue and heighten deleterious effects and neurodegeneration,activated microglia also perform neuroprotective functions such as debris phagocytosis and growth fa ctor secretion.Astrocytes can be activated into pro-inflammato ry phenotype A1 through a mechanism mediated by activated neuroinflammatory microglia,which could also mediate neurodegeneration.This A1 phenotype inhibits oligodendrocyte prolife ration and differe ntiation and is toxic to both oligodendrocytes and neurons.Howeve r,astroglial activation into phenotype A2 may also take place in response to neurodegeneration and as a protective mechanism.A variety of animal models mimicking specific multiple sclerosis features and the associated pathophysiological processes have helped establish the cascades of events that lead to the initiation,progression,and resolution of the disease.The colonystimulating facto r-1 receptor is expressed by myeloid lineage cells such as peripheral monocytes and macrophages and central nervous system microglia.Importantly,as microglia development and survival critically rely on colony-stimulating factor-1 receptor signaling,colony-stimulating factor-1 receptor inhibition can almost completely eliminate microglia from the brain.In this context,the present review discusses the impact of microglial depletion through colo ny-stimulating factor-1 receptor inhibition on demyelination,neurodegeneration,astroglial activation,and behavior in different multiple sclerosis models,highlighting the diversity of microglial effects on the progression of demyelinating diseases and the strengths and weaknesses of microglial modulation in therapy design.

CDP-choline to promote remyelination in multiple sclerosis:the need for a clinical trial

Multiple sclerosis is a multifactorial chronic inflammatory disease of the central nervous system that leads to demyelination and neuronal cell death,resulting in functional disability.Remyelination is the natural repair process of demyelination,but it is often incomplete or fails in multiple sclerosis.Available therapies reduce the inflammatory state and prevent clinical relapses.However,therapeutic approaches to increase myelin repair in humans are not yet available.The substance cytidine-5′-diphosphocholine,CDP-choline,is ubiquitously present in eukaryotic cells and plays a crucial role in the synthesis of cellular phospholipids.Regenerative properties have been shown in various animal models of diseases of the central nervous system.We have already shown that the compound CDPcholine improves myelin regeneration in two animal models of multiple sclerosis.However,the results from the animal models have not yet been studied in patients with multiple sclerosis.In this review,we summarise the beneficial effects of CDP-choline on biolipid metabolism and turnover with regard to inflammatory and regenerative processes.We also explain changes in phospholipid and sphingolipid homeostasis in multiple sclerosis and suggest a possible therapeutic link to CDP-choline.

The role of fibronectin in multiple sclerosis and the effect of drug delivery across the blood-brain barrier

Remyelination failure is one of the main characteristics of multiple sclerosis and is potentially correlated with disease progression.Previous research has shown that the extracellular matrix is associated with remyelination failure because remodeling of the matrix often fails in both chronic and progressive multiple sclerosis.Fibronectin aggregates are assembled and persistently exist in chronic multiple sclerosis,thus inhibiting remyelination.Although many advances have been made in the mechanisms and treatment of multiple sclerosis,it remains very difficult for drugs to reach pathological brain tissues;this is due to the complexity of brain structure and function,especially the existence of the blood-brain barrier.Therefore,herein,we review the effects of fibronectin aggregates on multiple sclerosis and the efficacy of different forms of drug delivery across the blood-brain barrier in the treatment of this disease.

Safety,immunogenicity,efficacy,and acceptability of COVID-19 vaccination in people with multiple sclerosis:a narrative review

In the last two years,a new seve re acute res piratory syndrome coronavirus(SARS-CoV)infection has spread worldwide leading to the death of millions.Va ccination represents the key factor in the global strategy against this pandemic,but it also poses several problems,especially for vulnerable people such as patients with multiple scle rosis.In this review,we have briefly summarized the main findings of the safety,efficacy,and acceptability of Coronavirus Disease 2019(COVID-19)vaccination fo r multiple sclerosis patients.Although the acceptability of COVID-19 vaccines has progressively increased in the last year,a small but significant part of patients with multiple sclerosis still has relevant concerns about vaccination that make them hesitant about receiving the COVID-19 vaccine.Overall,available data suggest that the COVID-19 vaccination is safe and effective in multiple scle rosis patients,even though some pharmacological treatments such as anti-CD20 therapies or sphingosine I-phosphate receptor modulato rs can reduce the immune response to vaccination.Accordingly,COVID-19 vaccination should be strongly recommended for people with multiple scle rosis and,in patients treated with anti-CD20 therapies and sphingosine I-phosphate receptor modulato rs,and clinicians should evaluate the appropriate timing for vaccine administration.Further studies are necessary to understand the role of cellular immunity in COVID-19 vaccination and the possible usefulness of booster jabs.On the other hand,it is mandatory to learn more about the reasons why people refuse vaccination.This would help to design a more effective communication campaign aimed at increasing vaccination coverage among vulnerable people.

Neuroimmune,clinical and treatment challenges in multiple sclerosis-related psychoses

In recent years,epidemiological and genetic studies have shown an association between autoimmune diseases and psychosis.The question arises whether patients with schizophrenia are more likely to develop multiple sclerosis(MS)later in life.It is well known that the immune system plays an important role in the etiopathogenesis of both disorders.Immune disturbances may be similar or very different in terms of different types of immune responses,disturbed myelination,and/or immunogenetic predispositions.A psychotic symptom may be a consequence of the MS diagnosis itself or a separate entity.In this review article,we discussed the timing of onset of psychotic symptoms and MS and whether the use of corticosteroids as therapy for acute relapses in MS is unfairly neglected in patients with psychiatric comorbidities.In addition,we discussed that the anti-inflammatory potential of antipsychotics could be useful and should be considered,especially in the treatment of psychosis that coexists with MS.Autoimmune disorders could precipitate psychotic symptoms,and in this context,autoimmune psychosis must be considered as a persistent symptomatology that requires continuous and specific treatment.

Exploring the mechanism of Yishen Daluo decoction in the treatment of multiple sclerosis based on network pharmacology and in vitro experiments

Objective:To explore the mechanism and related active components of Yishen Daluo decoction(YSDLD)in treating multiple sclerosis(MS).Methods:Targets of YSDLD were collected through the TCMSP,Chemistry,and TCMID databases.The MS targets were collected through OMIM,DrugBank,Gencards,TTD,and Pharmgkb databases.We built“componentetarget”network diagrams and proteineprotein interaction(PPI)diagrams and performed topological analysis.The targets were subjected to GO and KEGG enrichment analysis.Molecular docking verification was conducted on selected targets and molecules.Finally,in vitro experiments were con-ducted.BV2 cells were induced by lipopolysaccharide for model establishment.CCK8 experiment was conducted to explore the effect of YSDLD and RT-qPCR technology was used to explore the expression of key targets.Results:There were 184 active components in YSDLD and 898 targets of its action.There were 940 MS targets,and 215 targets were shared by YSDLD and MS.According to the“componentetarget”diagram,the top five key components included quercetin,kaempferol,beta-sitosterol,stigmasterol,and nar-ingenin.IL-6,IL-1 b,TNF-α,AKT1,and VEGFA were the important targets identified by PPI network to-pology analysis.A total of 564 functions were identified by GO enrichment analysis(P<0.01),mainly involving inflammatory response,hypoxia response,plasma membrane,neuronal cell body,protein phosphatase binding,and cytokine activity.KEGG enrichment analysis enriched 98 pathways(P<.01).YSDLD at the concentration of 20 m g/mL had no effect on BV2 cells.RT-qPCR indicated that YSDLD at the concentrations of 15 m g/mL and 20 m g/mL alleviated LPS-induced inflammatory injury and lowered the content of inflammatory factors(P<0.05).Conclusion:In this paper,the network pharmacology and in vitro experiments were used to explore the potential mechanism of YSDLD in treating MS.The research provides a good basis for the development of YSDLD and drugs for MS in future.

MicroRNAs as disease progression biomarkers and therapeutic targets in experimental autoimmune encephalomyelitis model of multiple sclerosis

Multiple sclerosis is an autoimmune neurodegenerative disease of the central nervous system characterized by pronounced inflammatory infiltrates entering the brain,spinal cord and optic nerve leading to demyelination.Focal demyelination is associated with relapsing-remitting multiple sclerosis,while progressive forms of the disease show axonal degeneration and neuronal loss.The tests currently used in the clinical diagnosis and management of multiple sclerosis have limitations due to specificity and sensitivity.MicroRNAs(miRNAs)are dysregulated in many diseases and disorders including demyelinating and neuroinflammatory diseases.A review of recent studies with the experimental autoimmune encephalomyelitis animal model(mostly female mice 6–12 weeks of age)has confirmed miRNAs as biomarkers of experimental autoimmune encephalomyelitis disease and importantly at the pre-onset(asymptomatic)stage when assessed in blood plasma and urine exosomes,and spinal cord tissue.The expression of certain miRNAs was also dysregulated at the onset and peak of disease in blood plasma and urine exosomes,brain and spinal cord tissue,and at the post-peak(chronic)stage of experimental autoimmune encephalomyelitis disease in spinal cord tissue.Therapies using miRNA mimics or inhibitors were found to delay the induction and alleviate the severity of experimental autoimmune encephalomyelitis disease.Interestingly,experimental autoimmune encephalomyelitis disease severity was reduced by overexpression of miR-146a,miR-23b,miR-497,miR-26a,and miR-20b,or by suppression of miR-182,miR-181c,miR-223,miR-155,and miR-873.Further studies are warranted on determining more fully miRNA profiles in blood plasma and urine exosomes of experimental autoimmune encephalomyelitis animals since they could serve as biomarkers of asymptomatic multiple sclerosis and disease course.Additionally,studies should be performed with male mice of a similar age,and with aged male and female mice.

The contribution of oligodendrocytes and oligodendrocyte progenitor cells to central nervous system repair in multiple sclerosis： perspectives for remyelination therapeutic strategies

Oligodencrocytes（OLs） are the main glial cells of the central nervous system involved in myelination of axons. In multiple sclerosis（MS）, there is an imbalance between demyelination and remyelination processes, the last one performed by oligodendrocyte progenitor cells（OPCs） and OLs, resulting into a permanent demyelination, axonal damage and neuronal loss. In MS lesions, astrocytes and microglias play an important part in permeabilization of blood-brain barrier and initiation of OPCs proliferation. Migration and differentiation of OPCs are influenced by various factors and the process is finalized by insufficient acummulation of OLs into the MS lesion. In relation to all these processes, the author will discuss the potential targets for remyelination strategies.

Protective effects of pharmacological therapies in animal models of multiple sclerosis: a review of studies 2014–2019

Multiple sclerosis(MS)is an inflammatory demyelinating disease of the central nervous system.The disability caused by inflammatory demyelination clinically dominates the early stages of relapsing-remitting MS and is reversible.Once there is considerable loss of axons,MS patients enter a secondary progressive stage.Disease-modifying drugs currently in use for MS suppress the immune system and reduce relapse rates but are not effective in the progressive stage.Various animal models of MS(mostly mouse and rat)have been established and proved useful in studying the disease process and response to therapy.The experimental autoimmune encephalomyelitis animal studies reviewed here showed that a chronic progressive disease can be induced by immunization with appropriate amounts of myelin oligodendrocyte glycoprotein together with mycobacterium tuberculosis and pertussis toxin in Freund's adjuvant.The clinical manifestations of autoimmune encephalomyelitis disease were prevented or reduced by treatment with certain pharmacological agents given prior to,at,or after peak disease,and the agents had protective effects as shown by inhibiting demyelination and damage to neurons,axons and oligodendrocytes.In the cuprizone-induced toxicity animal studies,the pharmacological agents tested were able to promote remyelination and increase the number of oligodendrocytes when administered therapeutically or prophylactically.A monoclonal IgM antibody protected axons in the spinal cord and preserved motor function in animals inoculated with Theiler's murine encephalomyelitis virus.In all these studies the pharmacological agents were administered singly.A combination therapy may be more effective,especially using agents that target neuroinflammation and neurodegeneration,as they may exert synergistic actions.

Metabolic checkpoints in neurodegenerative T helper 17（TH17） and neuroregenerative regulatory T(Treg) cells as new therapeutic targets for multiple sclerosis

The central nervous system (CNS) is an immune-privileged site with tightly-regulated immune responses, a concept proposed by Nobel Laureate Sir Peter Medawar in 1960. Under physiological conditions, only a few T lymphocytes conducting immunosurveillance can infiltrate the CNS.

Perspectives on neuroreparative therapies for treating multiple sclerosis

A need to develop neuroreparative therapies for multiple sclerosis（MS）：MS is the most common neurological disease of young Caucasian adults.This disease is characterized by inflammatory demyelination of the central nervous system（CNS）and involves activation of key inflammatory cells of both the adaptive and innate immune systems,which target and destroy both myelin and oligodendrocytes （the my- elin-forming glial cells in the CNS）. Key pathological features of the disease include autoimmune inflammation, axonal degeneration and demyelination （myelin loss）, latter of which can occur in both white matter and gray matter. The key cell type damaged in MS is oligodendrocytes, which produce the insulating myelin sheath surrounding many axons in the CNS. Myelin and oligodendrocytes have critical roles.

Galectin-3 prospects as a therapeutic agent for multiple sclerosis

Galectin-3 (Gal-3) in oligodendrocyte (OLG) differentiation: OLGs are the cells in charge of myelination in the central nervous system (CNS), allowing rapid conduction of the neural action potential and giving trophic support to axons. OLGs undergo a series of changes throughout their life cycle: first, upon neural stem cell comm让ment to the OLG lineage, cells referred to as OLG precursor cells (OPC) present a bipolar morphology, have proliferative and migratory capacity and express molecular markers like platelet-derived growth factor receptor alpha and neural/glial antigen 2.

Should mast cells be considered therapeutic targets in multiple sclerosis?

Mast cells are immune cells of the myeloid lineage that are found throughout the body,including the central nervous system.They perform many functions associated with innate and specific immunity,angiogenesis,and vascular homeostasis.Moreover,they have been implicated in a series of pathologies(e.g.,hypersensitivity reactions,tumors,and inflammatory disorders).In this review,we propose that this cell could be a relevant therapeutic target in multiple sclerosis,which is a central nervous system degenerative disease.To support this proposition,we describe the general biological properties of mast cells,their contribution to innate and specific immunity,and the participation of mast cells in the various stages of multiple sclerosis and experimental autoimmune encephalomyelitis development.The final part of this review is dedicated to an overview of the available mast cells immunomodulatory drugs and their activity on multiple sclerosis and experimental autoimmune encephalomyelitis,including our own experience related to the effect of ketotifen fumarate on experimental autoimmune encephalomyelitis evolution.

Positive frequency of autoantibodies in multiple sclerosis patients Are they associated with therapy?

BACKGROUND： Humoral autoimmunity in patients with multiple sclerosis is often asymptomatic and transient during interferon therapy. OBJECTIVE： To analyze the frequency of positivity to autoantibodies in multiple sclerosis patients and to clarify whether it is modified by immunomodulating therapy. DESIGN： A retrospective study.TIME AND SE＇rrlNG： The study was performed at the Multiple Sclerosis Center, Department of Neurosciences, Salerno Hospital, Italy, between 2005 and 2007. PARTICIPANTS： A total of 169 multiple sclerosis patients were included, 57 males and 112 females Individuals were mainly outpatients and were usually tested yearly for autoantibodies. Patients with previous immunological diseases were excluded from statistical evaluation. METHODS： The frequency of positivity was calculated in patients grouped for gender, multiple sclerosis clinical parameters, magnetic resonance imaging features and disease modifying therapy. A total of 113 patients were treated with beta interferons. MAIN OUTCOME MEASURES： Frequency of positivity to any autoantibody. Prevalences and incidences were calculated.RESULTS： The overall prevalence of autoantibodies within 3 years was 47.3%. In multiple sclerosis patients who were untreated or treated with drugs other than interferons, the prevalence was higher, and greater positivity to autoantibodies was seen in patients treated with interferons [odds ratio （95% confidence interval）, 2.87 （1.5 - 5.2）, P 〈 0.05 - 0.01]. Multiple regression analysis showed a significant association of the positivity to autoantibodies with interferon therapy, rather than gender, relapse or magnetic resonance imaging. CONCLUSION： Interferon therapy is associated with significantly higher frequency of autoantibodies in patients with multiple sclerosis. The differences among the therapies are not influenced by other variables such as gender or clinical pattern.

Sequencing of high-efficacy disease-modifying therapies in multiple sclerosis： perspectives and approaches

Multiple sclerosis（MS） is characterized by chronic inflammation in conjunction with neurodegeneration within the central nervous system. Most individuals with MS begin with a relapsing remitting course that later transitions to secondary progressive MS. Currently available disease-modifying therapies（DMTs） for relapsing MS have been demonstrated to reduce disease activity, however most patients require a change in therapy over the course of their disease. Treatment goals include the prevention of relapses and disability accumulation and to achieve this objective requires careful planning. Sequencing of DMTs for individual patients should be designed in such a way to maximize disease control and minimize risk based on the mechanism of action, pharmacokinetic and pharmacodynamic properties of each therapy. This includes the DMT patients are being switched from to those they are being switched to. The reversibility of immune system effects should be a key consideration for DMT sequence selection. This feature varies across DMTs and should factor more prominently in decision making as newer treatments become available for the prevention of disability accumulation in patients with progressive MS. In this short review, we discuss the landscape of existing therapies with an eye to the future when planning for optimal DMT sequencing. While no cure exists for MS, efforts are being directed toward research in neuroregeneration with the hope for positive outcomes.

Alemtuzumab: A Place in Therapy for Treatment of Multiple Sclerosis

Alemtuzumab is a humanized mononclonal antibody known to cause rapid depletion of B-and T-cell lymphocytes. Subsequent repletion of these lymphocytes leads to changes in adaptive immunity. Alemtuzumab is approved by the United States Food and Drug Administration (FDA) for the treatment of B-cell lymphocytic leukemia but has been investigated off-label in recent years for treatment of autoimmune diseases, including multiple sclerosis (MS). In MS treatment, alemtuzumab is administered as pulsed therapy, given once daily initially for 5 consecutive days and then for 3 consecutive days at 12-month intervals. Alemtuzumab has recently been compared to interferon beta 1-a in one phase II and two phase III trials in patients with relapsing-remitting MS. Results from the studies show alemtuzumab compared to interferon beta 1-a is associated with a greater reduction in the risk of sustained accumulation of disability and is more effective in reducing disease relapse rates. The treatment of MS continues to be a healthcare challenge due to the modest clinical benefit and adverse effect profiles of available disease modifying treatment options. Available data suggest alemtuzumab may offer better efficacy outcomes compared to traditional disease modifying therapies in patients with MS. However, the agent has not been compared to other new disease modifying medications that have been recently introduced.