Acting centrally or peripherally: A renewed interest in the central nervous system penetration of disease-modifying drugs in multiple sclerosis

Impact of High-Efficacy Therapies for Multiple Sclerosis on B Cells

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative autoimmune disorder of the central nervous system characterized by demyelination and neurodegeneration. Traditionally considered a T-cell-mediated disease, the crucial role of B lymphocytes in its pathogenesis, through different mechanisms contributing to inflammation and autoreactivity, is increasingly recognized. The risk of long-term disability in MS patients can be reduced by an early treatment initiation, in particular with high-efficacy therapies. The aim of this review is to provide an overview of the mechanisms of action of high-efficacy therapies for MS, with a focus on their impact on B cells and how this contributes to the drugs' efficacy and safety profiles. Anti-CD20 monoclonal antibodies, Alemtuzumab, Cladribine and sequestering therapies encompassing Natalizumab and S1P receptors modulators will be discussed and emerging therapies, including Bruton's Tyrosine Kinase inhibitors, will be presented.

Clinical opinions and case studies on understanding and managing hypogammaglobulinaemia in multiple sclerosis: United Kingdom perspective

BACKGROUND

Immunomodulatory disease-modifying therapies (DMTs) in multiple sclerosis (MS) have implications for secondary immunological effects and immunodeficiencies such as hypogammaglobulinaemia and reductions in immunoglobulin levels. Neurologists and treating healthcare professionals should be aware of hypogammaglobulinaemia and be able to manage resulting complications appropriately.

METHODS

This paper draws on brief clinical case studies in the United Kingdom to illustrate aspects of immunomodulatory DMTs in MS and aims to inform and increase understanding of the role of immunoglobulins in MS, including the presentation of reduced immunoglobulin levels and the interpretation of haematological parameters.

RESULTS AND CONCLUSIONS

Hypogammaglobulinaemia and prolonged or substantial reductions in immunoglobulin levels carry clinical implications for people living with MS. UK healthcare professionals working in MS can learn from other immunological specialities concerning the management of infection, vaccination, immunisation and treatment with different DMTs. They should be aware of how hypogammaglobulinaemia in MS presents and how to manage this in the context of DMTs, including the interpretation of haematological parameters and safety.

From diagnosis to treatment: exploring the mechanisms underlying optic neuritis in multiple sclerosis

Multiple sclerosis (MS) is a chronic autoimmune disease affecting the central nervous system, commonly causing sensory disturbances, motor weakness, impaired gait, incoordination and optic neuritis (ON). According to the statistics, up to 50% of MS patients experience vision problems during the disease course, suffering from blurred vision, pain, color vision deficits, and even blindness. Treatments have progressed from corticosteroids to therapies targeted against B/T cells. This review comprehensively and systematically reappraises the diagnostic methods for visual impairment in MS patients. It also summarizes the most recent treatment approaches and effective medications for ON in MS. Finally, we examine the immunoinflammatory mechanisms that underlie lesions in the central nervous system in multiple sclerosis, in order to direct future investigations to confirm these mechanisms in the visual pathway.

Ofatumumab for multiple sclerosis with disability accumulation

BACKGROUND

The ASCLEPIOS/APLIOS/APOLITOS/ALITHIOS trials highlighted the benefits of ofatumumab in reducing relapse rates and disability progression in multiple sclerosis (MS). However, its effects on patients with severe disability status remains uncertain. This study aimed to clarify the outcomes of ofatumumab in MS patients with high Expanded Disability Status Scale (EDSS) scores and prolonged disease durations.

METHODS

This is a retrospective cohort study of MS patients treated with ofatumumab at an MS center in Japan. At 12 months of treatment, patients with MS starting ofatumumab were classified into the treatment-responsive or treatment-resistant groups based on ofatumumab continuity, incidence of relapses with EDSS worsening, progression independent of relapse activity (PIRA). We used logistic regression analysis to identify factors associated with ofatumumab response.

RESULTS

Seventy patients were included in the analysis; 39 (56 %) patients were relapsing-remitting (RR), and 31 (44 %) patients were secondary progressive (SP) MS. Mean age at ofatumumab initiation, age at onset, and disease duration were 48.0, 33.9, and 14.1 years, respectively. The median EDSS was 4.5 (3.0-6.5); 38(56 %) patients were classified as resistant. The resistant rates by disease type were 33 % (13/39) and 81 % (26/31) for RR and SP MS, respectively. On multivariate analysis, EDSS and No evidence of disease activity (NEDA) 3 were independent factors for ofatumumab responsiveness (OR, 1.74, 0.04; 95 % CI, 1.17-2.73, 0.00-0.47; p = 0.01, 0.04).

CONCLUSION

Ofatumumab may yield more favorable effects when initiated in patients with MS with lower EDSS scores.

Cladribine tablets in relapsing-remitting multiple sclerosis preferentially target B-cells

Recent studies demonstrate the efficacy of B cell-targeting therapies in managing multiple sclerosis (MS) activity, emphasizing the critical role of B cells in MS pathogenesis. CladB study aimed to quantify the temporal changes in peripheral immune cells and their activity over 96 weeks of Cladribine tablets (CladT) treatment in relapsing-remitting MS (RRMS). Ten participants (3 males, 7 females) had blood samples collected at multiple intervals (Day 0, 1, 5, then weekly for 8 weeks, biweekly for up to 24 weeks, and monthly for up to 96 weeks) for immune cell analysis, compared to a historical alemtuzumab-treated cohort. Paired cerebrospinal fluid (CSF) was also taken for various analyses, alongside clinical and brain imaging assessments. CladT depleted memory B cells, while alemtuzumab rapidly depleted T and B cells. The кFLC index decreased from 164.5 ± 227.1 to 71.3 ± 84.7 at 48 weeks (p = 0.002) and to 64.4 ± 67.3 at 96 weeks (p = 0.01). The IgG index dropped from 1.1 ± 0.5 at baseline to 0.8 ± 0.4 at 48 weeks (p = 0.014) and to 0.8 ± 0.3 at 96 weeks (p = 0.02). CSF CXCL-13 decreased from 88.6 ± 68.4 pg/mL to 39.4 ± 35.2 pg/mL at 48 weeks (p = 0.037) and 19.1 ± 11.7 pg/mL at 96 weeks (p = 0.027). CSF NfL levels were reduced at 48 weeks (p = 0.01). CladT primarily depletes memory B cells and antibody-secreting cell precursors in RRMS, leading to sustained effects on intrathecal antibody production and total IgG, and a reduction in CSF CXCL-13.

The role of dopamine in the modulation of monocyte-induced Th17- and Th1-immune response in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) with autoimmune mechanism of development. The investigation of neuroimmune interaction is one of the most developing directions in MS pathogenesis study. Catecholamines are direct mediators of this interaction and can be involved in the pathogenesis of MS by modulating cells of both innate and adaptive immune systems. The aim of this study was to investigate the influence of dopamine and norepinephrine on the ability of monocytes of patients with relapsing-remitting MS, to induce Th17- and Th1-immune response, which play a crucial role in the autoimmunity of the CNS. We found, that both dopamine and norepinephrine modulate the production of Th17- (IL-23, IL-1β, and IL-6) and Th1-promoting (IL-12p70) cytokines by activated peripheral blood mononuclear cells or CD14+ monocytes in patients with MS and in healthy subjects. We also found the inhibitory effect of dopamine and norepinephrine on monocyte-induced production of IL-17 and IFN-γ by autologous CD4+ T-cells in both groups. Finally, the multidirectional role of D1- and D2-like dopaminergic receptors in the modulatory effect of dopamine on the ability of CD14+ monocytes to activate CD4+ T-cells was established, expanding the potential role of dopamine in the neuroimmune interaction.

Sphingosine 1-phosphate receptor modulators in multiple sclerosis treatment: A practical review

Four sphingosine 1-phosphate (S1P) receptor modulators (fingolimod, ozanimod, ponesimod, and siponimod) are approved by the US Food and Drug Administration for the treatment of multiple sclerosis. This review summarizes efficacy and safety data on these S1P receptor modulators, with an emphasis on similarities and differences. Efficacy data from the pivotal clinical trials are generally similar for the four agents. However, because no head-to-head clinical studies were conducted, direct efficacy comparisons cannot be made. Based on the adverse event profile of S1P receptor modulators, continued and regular monitoring of patients during treatment will be instructive. Notably, the authors recommend paying attention to the cardiac monitoring guidelines for these drugs, and when indicated screening for macular edema and cutaneous malignancies before starting treatment. To obtain the best outcome, clinicians should choose the drug based on disease type, history, and concomitant medications for each patient. Real-world data should help to determine whether there are meaningful differences in efficacy or side effects between these agents.

Remyelinating effect driven by transferrin-loaded extracellular vesicles

Extracellular vesicles (EVs) are involved in diverse cellular functions, playing a significant role in cell-to-cell communication in both physiological conditions and pathological scenarios. Therefore, EVs represent a promising therapeutic strategy. Oligodendrocytes (OLs) are myelinating glial cells developed from oligodendrocyte progenitor cells (OPCs) and damaged in chronic demyelinating diseases such as multiple sclerosis (MS). Glycoprotein transferrin (Tf) plays a critical role in iron homeostasis and has pro-differentiating effects on OLs in vivo and in vitro. In the current work, we evaluated the use of EVs as transporters of Tf to the central nervous system (CNS) through the intranasal (IN) route. For the in vitro mechanistic studies, we used rat plasma EVs. Our results show that EVTf enter OPCs through clathrin-caveolae and cholesterol-rich lipid raft endocytic pathways, releasing the cargo and exerting a pro-maturation effect on OPCs. These effects were also observed in vivo using the animal model of demyelination induced by cuprizone (CPZ). In this model, IN administered Tf-loaded EVs isolated from mouse plasma reached the brain parenchyma, internalizing into OPCs, promoting their differentiation, and accelerating remyelination. Furthermore, in vivo experiments demonstrated that EVs protected the Tf cargo and significantly reduced the amount of Tf required to induce remyelination as compared to soluble Tf. Collectively, these findings unveil EVs as functional nanocarriers of Tf to induce remyelination.

Ocrelizumab associates with reduced cerebrospinal fluid B and CD20dim CD4+ T cells in primary progressive multiple sclerosis

The anti-CD20 monoclonal antibody ocrelizumab reduces disability progression in primary progressive multiple sclerosis. CD20 is a prototypical B-cell marker; however, subpopulations of CD4+ and CD8+ T cells in peripheral blood and cerebrospinal fluid also express low levels of CD20 (CD20dim). Therefore, direct targeting and depletion of these CD20dim T-cell subpopulations may contribute to the therapeutic effect of ocrelizumab. The aim of this observational cohort study was to compare CD20+ B-cell and CD20dim T-cell distributions between peripheral blood and cerebrospinal fluid of ocrelizumab-treated or ocrelizumab-untreated people with primary progressive multiple sclerosis. Ocrelizumab treatment was associated with depletion of circulating B cells and CD20dim CD4+ and CD20dim CD8+ T cells (P < 0.0001, P = 0.0016 and P = 0.0008, respectively) but, in cerebrospinal fluid, only with lower proportions of B cells and CD20dim memory CD4+ T cells (P < 0.0001 and P = 0.0043, respectively). The proportional prevalence of cerebrospinal fluid CD20dim memory CD8+ T cells was not significantly reduced (P = 0.1333). Only in cerebrospinal fluid, the proportions of CD20dim cells within CD4+ and not CD8+ T cells positive for CCR5, CCR6 and CXCR3 were reduced in ocrelizumab-treated participants. The proportion of CD20dim CD4+ T cells and abundance of CD4+ relative to CD8+ T cells in cerebrospinal fluid correlated positively with age (R = 0.6799, P = 0.0150) and Age-Related Multiple Sclerosis Severity score (R = 0.8087, P = 0.0014), respectively. We conclude that, in contrast to cerebrospinal fluid CD20dim CD8+ T cells, B cells and CD20dim CD4+ T cells are reduced in cerebrospinal fluid of people with primary progressive multiple sclerosis with an ocrelizumab-associated depletion of circulating B cells and CD20dim T cells. Therefore, these cells are likely to contribute to the therapeutic effects of ocrelizumab in people with primary progressive multiple sclerosis.

Hallmarks of spinal cord pathology in multiple sclerosis

A disparity exists between spinal cord and brain involvement in multiple sclerosis (MS), each independently contributing to disability. Underlying differences between brain and cord are not just anatomical in nature (volume, white/grey matter organization, vascularization), but also in barrier functions (differences in function and composition of the blood-spinal cord barrier compared to blood-brain barrier) and possibly in repair mechanisms. Also, immunological phenotypes seem to influence localization of inflammatory activity. Whereas the brain has gained a lot of attention in MS research, the spinal cord lags behind. Advanced imaging techniques and biomarkers are improving and providing us with tools to uncover the mechanisms of spinal cord pathology in MS. In the present review, we elaborate on the underlying anatomical and physiological factors driving differences between brain and cord involvement in MS and review current literature on pathophysiology of spinal cord involvement in MS and the observed differences to brain involvement.

Toward identifying key mechanisms of progression in multiple sclerosis

A major therapeutic goal in the treatment of multiple sclerosis (MS) is to prevent the accumulation of disability over an often decades-long disease course. Disability progression can result from acute relapses as well as from CNS intrinsic parenchymal disintegration without de novo CNS lesion formation. Research focus has shifted to progression not associated with acute inflammation, as it is not sufficiently controlled by currently available treatments. This review outlines how recent advances in the understanding of the pathogenesis of progressive MS have been facilitated by the development of more precise, less static pathogenetic concepts of progressive MS, as well as by new techniques for the analysis of region-specific proteomic and transcriptomic signatures in the human CNS. We highlight key drivers of MS disease progression and potential targets in its treatment.

[The role of dopamine receptors in the modulation of mononuclear phagocytes in multiple sclerosis]

OBJECTIVE

To investigate the role of dopamine receptor D1DR and D2DR in the production of cytokines interleukin-6 (IL-6) and IL-1β by monocytes and macrophages in patients with relapsing-remitting multiple sclerosis (MS).

MATERIAL AND METHODS

Ten patients with relapsing-remitting MS and 10 healthy subjects were examined. The level of IL-6 and IL-1β production was assessed in culture supernatants obtained from CD14+ monocytes or macrophages stimulated with interferon-γ (IFN-γ) and lipopolysaccharide (LPS). To study the role of dopamine receptors in the regulation of CD14+ monocytes or macrophages, samples of cells were incubated in the presence of specific D1DR or D2DR antagonists, after which IFN-γ/LPS were added to the cultures. Levels of cytokines in culture supernatants were measured by enzyme-linked immunosorbent assay.

RESULTS

The production of IL-6 and IL-1β by CD14+ monocytes and macrophages was comparable between the groups. Blockade of D1DR suppressed cytokine production by CD14+ monocytes and macrophages in both groups. In contrast, blockade of D2DR increased the production of cytokines by CD14+ monocytes and did not affect cytokine production by macrophages in both groups.

CONCLUSIONS

Targeting of dopaminergic receptors could be considered as an additional mechanism of immunomodulation in MS with both pro- and anti-inflammatory effects on cells of the innate immune system.

Innovative drug delivery strategies to the CNS for the treatment of multiple sclerosis

Disorders of the central nervous system (CNS), such as multiple sclerosis (MS) represent a great emotional, financial and social burden. Despite intense efforts, great unmet medical needs remain in that field. MS is an autoimmune, chronic inflammatory demyelinating disease with no curative treatment up to date. The current therapies mostly act in the periphery and seek to modulate aberrant immune responses as well as slow down the progression of the disease. Some of these therapies are associated with adverse effects related partly to their administration route and show some limitations due to their rapid clearance and inability to reach the CNS. The scientific community have recently focused their research on developing MS therapies targeting different processes within the CNS. However, delivery of therapeutics to the CNS is mainly limited by the presence of the blood-brain barrier (BBB). Therefore, there is a pressing need to develop new drug delivery strategies that ensure CNS availability to capitalize on identified therapeutic targets. Several approaches have been developed to overcome or bypass the BBB and increase delivery of therapeutics to the CNS. Among these strategies, the use of alternative routes of administration, such as the nose-to-brain (N2B) pathway, offers a promising non-invasive option in the scope of MS, as it would allow a direct transport of the drugs from the nasal cavity to the brain. Moreover, the combination of bioactive molecules within nanocarriers bring forth new opportunities for MS therapies, allowing and/or increasing their transport to the CNS. Here we will review and discuss these alternative administration routes as well as the nanocarrier approaches useful to deliver drugs for MS.

Bioavailable central nervous system disease-modifying therapies for multiple sclerosis

Disease-modifying therapies for relapsing multiple sclerosis reduce relapse rates by suppressing peripheral immune cells but have limited efficacy in progressive forms of the disease where cells in the central nervous system play a critical role. To our knowledge, alemtuzumab, fumarates (dimethyl, diroximel, and monomethyl), glatiramer acetates, interferons, mitoxantrone, natalizumab, ocrelizumab, ofatumumab, and teriflunomide are either limited to the periphery or insufficiently studied to confirm direct central nervous system effects in participants with multiple sclerosis. In contrast, cladribine and sphingosine 1-phosphate receptor modulators (fingolimod, ozanimod, ponesimod, and siponimod) are central nervous system-penetrant and could have beneficial direct central nervous system properties.

The role of biogenic amines in the modulation of monocytes in autoimmune neuroinflammation

Multiple sclerosis (MS) is inflammatory demyelinating and neurodegenerative disease of the central nervous system (CNS) with autoimmune mechanism of development. The study of the neuroimmune interactions is one of the most developing directions in the research of the pathogenesis of MS. The influence of biogenic amines on the pathogenesis of experimental autoimmune encephalomyelitis (EAE) and MS was shown by the modulation of subsets of T-helper cells and B-cells, which plays a crucial role in the autoimmunity of the CNS. However, along with T- and B-cells the critical involvement of mononuclear phagocytes such as dendritic cells, macrophages, and monocytes in the development of neuroinflammation also was shown. It was demonstrated that the activation of microglial cells (resident macrophages of the CNS) could initiate the neuroinflammation in the EAE, suggesting their role at an early stage of the disease. In contrast, monocytes, which migrate from the periphery into the CNS through the blood-brain barrier, mediate the effector phase of the disease and cause neurological disability in EAE. In addition, the clinical efficacy of the therapy with depletion of the monocytes in EAE was shown, suggesting their crucial role in the autoimmunity of the CNS. Biogenic amines, such as epinephrine, norepinephrine, dopamine, and serotonin are direct mediators of the neuroimmune interaction and may affect the pathogenesis of EAE and MS by modulating the immune cell activity and cytokine production. The anti-inflammatory effect of targeting the biogenic amines receptors on the pathogenesis of EAE and MS by suppression of Th17- and Th1-cells, which are critical for the CNS autoimmunity, was shown. However, the latest data showed the potential ability of biogenic amines to affect the functions of the mononuclear phagocytes and their involvement in the modulation of neuroinflammation. This article reviews the literature data on the role of monocytes in the pathogenesis of EAE and MS. The data on the effect of targeting of biogenic amine receptors on the function of monocytes are presented.

Evaluation of Temozolomide and Fingolimod Treatments in Glioblastoma Preclinical Models

Glioblastomas are malignant brain tumors which remain lethal due to their aggressive and invasive nature. The standard treatment combines surgical resection, radiotherapy, and chemotherapy using Temozolomide, albeit with a minor impact on patient prognosis (15 months median survival). New therapies evaluated in preclinical translational models are therefore still required to improve patient survival and quality of life. In this preclinical study, we evaluated the effect of Temozolomide in different models of glioblastoma. We also aimed to investigate the efficacy of Fingolimod, an immunomodulatory drug for multiple sclerosis also described as an inhibitor of the sphingosine-1-phosphate (S1P)/S1P receptor axis. The effects of Fingolimod and Temozolomide were analyzed with in vitro 2D and 3D cellular assay and in vivo models using mouse and human glioblastoma cells implanted in immunocompetent or immunodeficient mice, respectively. We demonstrated both in in vitro and in vivo models that Temozolomide has a varied effect depending on the tumor type (i.e., U87MG, U118MG, U138MG, and GL261), demonstrating sensitivity, acquired resistance, and purely resistant tumor phenotypes, as observed in patients. Conversely, Fingolimod only reduced in vitro 2D tumor cell growth and increased cytotoxicity. Indeed, Fingolimod had little or no effect on 3D spheroid cytotoxicity and was devoid of effect on in vivo tumor progression in Temozolomide-sensitive models. These results suggest that the efficacy of Fingolimod is dependent on the glioblastoma tumor microenvironment. Globally, our data suggest that the response to Temozolomide varies depending on the cancer model, consistent with its clinical activity, whereas the potential activity of Fingolimod may merit further evaluation.

From bedside to bench: how existing therapies inform the relationship between Epstein-Barr virus and multiple sclerosis

Therapy for relapsing-remitting multiple sclerosis (MS) has advanced dramatically despite incomplete understanding of the cause of the condition. Current treatment involves inducing broad effects on immune cell populations with consequent off-target side effects, and no treatment can completely prevent disability progression. Further therapeutic advancement will require a better understanding of the pathobiology of MS. Interest in the role of Epstein-Barr virus (EBV) in multiple sclerosis has intensified based on strong epidemiological evidence of an association between EBV seroprevalence and MS. Hypotheses proposed to explain the biological relationship between EBV and MS include molecular mimicry, EBV immortalised autoreactive B cells and infection of glial cells by EBV. Examining the interaction between EBV and immunotherapies that have demonstrated efficacy in MS offers clues to the validity of these hypotheses. The efficacy of B cell depleting therapies could be consistent with a hypothesis that EBV-infected B cells drive MS; however, loss of T cell control of B cells does not exacerbate MS. A number of MS therapies invoke change in EBV-specific T cell populations, but pathogenic EBV-specific T cells with cross-reactivity to CNS antigen have not been identified. Immune reconstitution therapies induce EBV viraemia and expansion of EBV-specific T cell clones, but this does not correlate with relapse. Much remains unknown regarding the role of EBV in MS pathogenesis. We discuss future translational research that could fill important knowledge gaps.

[New neuroimaging methods in assessing the activity of neuroinflammation in multiple sclerosis]

The review presents current data on the use of positron emission tomography and single-photon emission computed tomography in multiple sclerosis (MS) to assess the activity of the pathological process, including neuroinflammation, demyelination, activation of microglia, neurodegeneration and local blood flow disorders. These methodologies are a new approach for studying the mechanisms of action and evaluating the clinical effect of disease modifying therapy of MS, especially those capable of penetrating into brain tissue. Among them, the most attention is attracted by cladribine tablets acting on the mechanism of immune reconstitution therapy, most likely with the modulation of immune reactions directly in the brain tissue.

[The influence of fluoxetine on neuroimmune interaction in multiple sclerosis]

OBJECTIVE

To study the effect of fluoxetine on Th17- and Th1-immune response, which plays an important role in the pathogenesis of multiple sclerosis (MS).

MATERIAL AND METHODS

Ten patients with relapsing-remitting MS and ten healthy subjects were examined. The functions of Th17- and Th1-immune responses were assessed by the production of cytokines interleukin-17 (IL-17) and interferon-gamma (IFN-γ) by CD4+ T cells stimulated with macrophages or microbeads coated with anti-CD3 and anti-CD28-antibodies. To assess the effect of fluoxetine on the macrophages-induced Th17- and Th1-immune response, macrophages were pre-incubated in the presence of fluoxetine and co-cultured with autologous CD4+ T-cells. In the case of stimulation of CD4+ T-cells with anti-CD3/CD28-microbeads, fluoxetine was added directly to the T-helper cells before adding of microbeads. In addition, we evaluated the effect of fluoxetine on the production of the factors of differentiation of Th17-cells cytokines IL-6 and IL-1β by macrophages. The levels of cytokines in the cell culture supernatants were measured by ELISA.

RESULTS

The production of IL-17 and IFN-γ by CD4+ T-cells stimulated with macrophages or anti-CD3/CD28-microbeads was comparable between the groups. Fluoxetine suppressed the production of IL-17 and IFN-γ by anti-CD/CD28-stimulated CD4+ T-cells in both groups. Fluoxetine also suppressed the production of IL-6 and IL-1β by macrophages as well as their ability to induce IL-17 and IFN-γ production by CD4+ T-cells in both groups.

CONCLUSIONS

Fluoxetine may have an anti-inflammatory effect in MS that could be mediated by suppression of Th17- and Th1-cells or macrophage-induced Th17- and Th1-immune response.

Diroximel Fumarate as a Novel Oral Immunomodulating Therapy for Relapsing Forms of Multiple Sclerosis: A Review on the Emerging Data

Multiple sclerosis (MS) is a chronic inflammatory, demyelinating and neurodegenerative disorder of the central nervous system. Disease-modifying drugs (DMDs) and subsequent adherence are crucial for preventing reversible episodes of neurological dysfunction and delayed onset of progressive accumulation of irreversible deficits. Yet, side effects may limit their usage in clinical practice. Gastrointestinal (GI) side effects are a significant limitation of the use of dimethyl fumarate (DMF), the most frequently prescribed oral DMD in MS worldwide. Diroximel fumarate (DRF) is a second-generation oral fumaric acid ester (FAE) that was developed as a formulation with better GI tolerability. The improved tolerability is assumed to be related to a lower synthesis of gut-irritating methanol. Other explanations for DRF’s lower extent of GI irritation include a more modest off-target activity due to its chemical structure. The superior GI tolerability of DRF compared to DMF could be proven in clinical trials and lead to approval of DRF for the treatment of relapsing forms of MS/relapsing-remitting MS (United States Food and Drug Administration and European Medicines Agency, respectively). Here, we summarize the mode of action of oral FAE and compare the chemical and physiological characteristics of DMF and DRF. Moreover, we discuss the adverse effects of FAE and introduce the emerging preclinical and trial data leading to the approval of DRF in MS. This article additionally reviews our current understanding of coronavirus disease 2019 (COVID-19) and the efficacy of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) vaccination in people treated with FAE.

Th17-cells in depression: Implication in multiple sclerosis

Depression is one of the most common neuropsychological symptoms of multiple sclerosis. However, in addition to mood disorder, depression can also influence on multiple sclerosis course. The mechanism of this dependence is not fully understood. The recent studies suggest the possible common immune mechanisms in the pathogenesis of depression and multiple sclerosis. In particular, it was shown that along with biogenic amines disturbance, neuroinflammation also play an important role in the pathogenesis of depression. Significant attention is drawn to Th17-cells subsets, which are considered as critical players in the pathogenesis of inflammatory diseases of the central nervous system, including multiple sclerosis. This brief report reviews the literature data on the role of neuroinflammation in the reciprocal influence of multiple sclerosis and depression with focus on Th17-cells, which may underlie pathogenetic mechanisms of both this diseases.

Cladribine Treatment for MS Preserves the Differentiative Capacity of Subsequently Generated Monocytes, Whereas Its Administration In Vitro Acutely Influences Monocyte Differentiation but Not Microglial Activation

Cladribine (2-chlorodeoxyadenosine, 2CdA) is one of the most effective disease-modifying drugs for multiple sclerosis (MS). Cladribine is a synthetic purine nucleoside analog that induces cell death of lymphocytes and oral cladribine treatment leads to a long-lasting disease stabilization, potentially attributable to immune reconstitution. In addition to its effects on lymphocytes, cladribine has been shown to have immunomodulatory effects on innate immune cells, including dendritic cells and monocytes, which could also contribute to its therapeutic efficacy. However, whether cladribine can modulate human macrophage/microglial activation or monocyte differentiation is currently unknown. The aim of this study was to determine the immunomodulatory effects of cladribine upon monocytes, monocyte-derived macrophages (MDMs) and microglia. We analyzed the phenotype and differentiation of monocytes from MS patients receiving their first course of oral cladribine both before and three weeks after the start of treatment. Flow cytometric analysis of monocytes from MS patients undergoing cladribine treatment revealed that the number and composition of CD14/CD16 monocyte subsets remained unchanged after treatment. Furthermore, after differentiation with M-CSF, such MDMs from treated MS patients showed no difference in gene expression of the inflammatory markers compared to baseline. We further investigated the direct effects of cladribine in vitro using human adult primary MDMs and microglia. GM-CSF-derived MDMs were more sensitive to cell death than M-CSF-derived MDMs. In addition, MDMs treated with cladribine showed increased expression of costimulatory molecules CD80 and CD40, as well as expression of anti-inflammatory, pro-trophic genes IL10 and MERTK, depending on the differentiation condition. Cladribine treatment in vitro did not modulate the expression of activation markers in human microglia. Our study shows that cladribine treatment in vitro affects the differentiation of monocytes into macrophages by modulating the expression of activation markers, which might occur similarly in tissue after their infiltration in the CNS during MS.

Cladribine Tablets for Relapsing-Remitting Multiple Sclerosis: A Clinician's Review

Multiple sclerosis (MS) is a chronic neurodegenerative disease characterized by inflammation and demyelination for which there is currently no cure; therefore, the aim of therapy is to reduce the risk of relapse and disability progression. The treatment options for MS have increased greatly in recent years with the development of several disease-modifying therapies (DMTs) and the advent of immune reconstitution therapy (IRT). IRTs are administered in short-dosing periods to produce long-term effects on the immune system. Treatment with an IRT is based on the 3Rs: reduction, repopulation, and reconstitution of lymphocytes, which leads to restoration of immune effector functions. Cladribine tablets represent a selective, high-efficacy, oral form of IRT for patients with MS that targets lymphocytes and spares innate immune cells. Patients require only two weekly treatment courses, with each course comprising two treatment weeks, in Years 1 and 2; therefore, cladribine tablets are associated with a lower monitoring burden than many other DMTs, while short dosing periods can help to improve adherence. This review provides an overview of IRT and offers the clinician's perspective on the current MS treatment landscape, with a focus on practical advice for the management of patients undergoing treatment with cladribine tablets based on the most recent evidence available, including risks associated with COVID-19 and recommendations for vaccination in patients with MS.

The Dual Role of the β2-Adrenoreceptor in the Modulation of IL-17 and IFN-γ Production by T Cells in Multiple Sclerosis

Norepinephrine is a neurotransmitter that also has an immunomodulatory effect and is involved in multiple sclerosis (MS) pathogenesis. This study aimed to clarify the role of the β₂-adrenoreceptor in the norepinephrine-mediated modulation of interleukin-17 (IL-17) and interferon-γ (IFN-γ) production, which play a critical pathogenetic role in MS. CD4⁺ T cells obtained from twenty-five relapsing-remitting MS patients and sixteen healthy subjects were cultured ex vivo with norepinephrine and/or β₂-adrenoreceptor antagonist or agonist, followed by a cytokine production analysis using ELISA. Norepinephrine suppressed IL-17 and IFN-γ production by the anti-CD3/anti-CD28-microbead-stimulated CD4⁺ T cells in both groups. Blockade of the β₂-adrenoreceptor with the specific antagonist ICI 118.551 enhanced norepinephrine-mediated IL-17 suppression but decreased its inhibitory effect on IFN-γ production in MS patients. In contrast, the β₂-adrenoreceptor agonist formoterol did not influence norepinephrine’s inhibitory effect on cytokine production in both groups. The blockade of the β₂-adrenoreceptor, even in the absence of exogenous norepinephrine, suppressed IL-17 production but did not influence IFN-γ production in both groups. Conversely, β₂-adrenoreceptor activation by formoterol decreased IFN-γ production and did not affect IL-17 production in both groups. These data illustrate the inhibitory effect of norepinephrine on IL-17 and IFN-γ production by CD4⁺ T cells in MS. The inhibitory effect of norepinephrine on IFN-γ production by CD4⁺ T cells in MS could be mediated via β₂-adrenoreceptor activation.