Recurrence of severe symptomatic late-onset neutropenia on ocrelizumab.

BACKGROUND: Late-onset neutropenia (LON), defined as an absolute neutrophil count (ANC) < 1500/mm3 that develops between 4 weeks and 6 months after the last drug administration, is a rare side effect of anti-CD20 drugs including ocrelizumab. Although continuation of ocrelizumab after LON is not contraindicated, the risk of LON recurrence is not well known. CASES: We report three cases of recurrent symptomatic agranulocytosis (ANC < 500/mm3) occurring under ocrelizumab. CONCLUSION: Given the risk of recurrence of symptomatic agranulocytosis and the availability of other treatments, a therapeutic switch may be discussed after the first episode of LON.

Clinical correlates of respiratory disorders in patients with severe multiple sclerosis: A cross-sectional cohort.

BACKGROUND: Respiratory disorders remain incompletely described in multiple sclerosis (MS), even though they are a frequent cause of death. METHODS: The objective was to describe respiratory disorders in MS patients with Expanded Disability Status Score (EDSS) ⩾ 6.5. Diaphragm dysfunction was defined by at least two of the seven criteria: clinical signs, inspiratory recruitment of neck muscles during wakefulness, reduced upright vital capacity (VC) < 80%, upright-to-supine VC ⩾ 15% of upright VC, decrease in Maximal Inspiratory Pressure < 60%, phasic activation of inspiratory neck muscles during sleep, and opposition of thoracic and abdominal movements during sleep. Cough weakness was defined by a peak cough flow < 270 L/min and/or need for cough assist. Sleep apnea syndrome was defined by an apnea-hypopnea index ⩾ 15. RESULTS: Notably, 71 MS patients were included: median age 54 [48, 61] years; median disease duration 21.4 [16.0, 31.4] years. Of these, 52 patients had one or more respiratory disorders; diaphragm dysfunction was the most frequent (n = 34). Patients with diaphragm dysfunction and cough weakness were more disabled. The fatigue score and the cognitive evaluations did not differ between the groups. Five patients required non-invasive ventilation. CONCLUSION: Respiratory disorders are frequent in severe MS, mostly diaphragm dysfunction. Of interest, instrumental interventions are available to address these disorders.

Monitoring recovery after CNS demyelination, a novel tool to de-risk pro-remyelinating strategies.

In multiple sclerosis, while remarkable progress has been accomplished to control the inflammatory component of the disease, repair of demyelinated lesions is still an unmet need. Despite encouraging results generated in experimental models, several candidates favouring or promoting remyelination have not reached the expected outcomes in clinical trials. One possible reason for these failures is that, in most cases, during preclinical testing, efficacy was evaluated on histology only, while functional recovery had not been assessed. We have generated a Xenopus laevis transgenic model Tg(mbp:GFP-NTR) of conditional demyelination in which spontaneous remyelination can be accelerated using candidate molecules. Xenopus laevis is a classic model for in vivo studies of myelination because tadpoles are translucent. We reasoned that demyelination should translate into loss of sensorimotor functions followed by behavioural recovery upon remyelination. To this end, we measured the swimming speed and distance travelled before and after demyelination and during the ongoing spontaneous remyelination and have developed a functional assay based on the visual avoidance of a virtual collision. Here we show that alteration of these functional and clinical performances correlated well with the level of demyelination and that histological remyelination, assayed by counting in vivo the number of myelinating oligodendrocytes in the optic nerve, translated in clinical-functional recovery. This method was further validated in tadpoles treated with pro-remyelinating agents (clemastine, siponimod) showing that increased remyelination in the optic nerve was associated with functional improvement. Our data illustrate the potential interest of correlating histopathological parameters and functional-clinical parameters to screen molecules promoting remyelination in a simple in vivo model of conditional demyelination.

Oligodendrocyte progenitor cell recruitment and remyelination in multiple sclerosis: the more, the merrier?

Promoting remyelination to prevent/reduce neurodegeneration in patients with multiple sclerosis (MS) is a major therapeutic goal. The longstanding view that the block of oligodendrocyte progenitor cell (OPC) differentiation in MS lesions is the leading cause of remyelination failure has inspired the scientific community to focus primarily on OPC differentiation-promoting compounds as pro-remyelinating agents. Yet, these strategies have been challenged by findings that active MS lesions contain surviving oligodendrocytes that may contribute to remyelination, while many chronic lesions contain low numbers of oligodendroglial cells. In addition, clinical trials using differentiation-stimulating drugs have shown limited efficacy. Thus, a strategic shift in the design of potential remyelination-promoting therapies may be required to achieve significant clinical benefits, which calls for a careful reconsideration of the mechanisms underlying remyelination failure in MS. Here, we argue that both the rate and the efficacy of OPC recruitment are fundamental determinants of remyelination, and that stimulating this process in MS may be crucial to achieve myelin regeneration. We first review different types of MS lesions in early and chronic MS, with a particular focus on OPCs and surviving oligodendrocytes. Based on the neuropathological findings and results obtained using models of demyelination, we make the case that OPC differentiation block in chronic MS is likely the consequence of defective OPC recruitment during earlier phases of the disease, because (i) if the recruitment is too slow, OPCs reach the axons after what we define as 'remyelination-permissive window', and thus remain undifferentiated; and (ii) if the recruitment is inefficient, OPC density in the lesions remains below the threshold required for differentiation. Importantly, we highlight that OPC proliferation in MS lesions is scarce, which strongly suggests that repeated episodes of demyelination/remyelination (OPC differentiation) will deplete the lesional OPC pool unless perilesional OPCs are recruited. We also point out that surviving mature oligodendrocytes in a subtype of early MS lesions may actually prevent the recruitment of OPCs. Because it has been suggested that OPC-mediated remyelination may be more efficient than that by surviving oligodendrocytes, we suggest that stimulating OPC recruitment during active disease should benefit remyelination in multiple types of lesions, including those with spared oligodendrocytes. Finally, we review molecular determinants of OPC recruitment and suggest a potential therapeutically-relevant strategy to increase this process in patients with MS.

Endogenous clues promoting remyelination in multiple sclerosis.

PURPOSE OF REVIEW: The introduction some 30 years ago of ß-interferon, followed by a panel of immunomodulators and immunosuppressants has led to a remarkable improvement in the management of multiple sclerosis (MS) patients. Despite these noticeable progresses, which lower the number of relapses and thereby ameliorate patients' quality of life, preventing long-term progression of disability is still an unmet need, highlighting the necessity to develop therapeutic strategies aimed at repairing demyelinated lesions and protecting axons from degeneration. The capacity of human brain to self-regenerate demyelinated lesion has opened a field of research aimed at fostering this endogenous potential. RECENT FINDINGS: The pioneer electron microscopic evidence by Périer and Grégoire [Périer O, Grégoire A. Electron microscopic features of multiple sclerosis lesions. Brain 1965; 88:937-952] suggesting the capacity of human brain to self-regenerate demyelinated lesion has opened a field of research aimed at fostering this endogenous potential. Here we review some recently identified mechanisms involved in the remyelination process, focusing on the role of electrical activity and the involvement of innate immune cells. We then provide an update on current strategies promoting endogenous myelin repair. SUMMARY: Identification of therapeutic targets for remyelination has opened an active therapeutic field in MS. Although still in early phase trials, with heterogenous efficacy, the door for myelin regeneration in MS is now opened.

Anti-CD20 therapies decrease humoral immune response to SARS-CoV-2 in patients with multiple sclerosis or neuromyelitis optica spectrum disorders.

BACKGROUND: SARS-CoV-2 seroconversion rate after COVID-19 may be influenced by disease-modifying therapies (DMTs) in patients with multiple sclerosis (MS) or neuromyelitis optica spectrum disorders (NMO-SD). OBJECTIVE: To investigate the seroprevalence and the quantity of SARS-CoV-2 antibodies in a cohort of patients with MS or NMO-SD. METHODS: Blood samples were collected in patients diagnosed with COVID-19 between 19 February 2020 and 26 February 2021. SARS-CoV-2 antibody positivity rates and Ig levels (anti-S IgG titre, anti-S IgA index, anti-N IgG index) were compared between DMTs groups. Multivariate logistic and linear regression models were used to estimate the influence of DMTs and other confounding variables on SARS-CoV-2 serological outcomes. RESULTS: 119 patients (115 MS, 4 NMO, mean age: 43.0 years) were analysed. Overall, seroconversion rate was 80.6% within 5.0 (SD 3.4) months after infection. 20/21 (95.2%) patients without DMT and 66/77 (85.7%) patients on DMTs other than anti-CD20 had at least one SARS-CoV-2 Ig positivity, while this rate decreased to only 10/21 (47.6%) for patients on anti-CD20 (p<0.001). Being on anti-CD20 was associated with a decreased odd of positive serology (OR, 0.07 (95% CI 0.01 to 0.69), p=0.02) independently from time to COVID-19, total IgG level, age, sex and COVID-19 severity. Time between last anti-CD20 infusion and COVID-19 was longer (mean (SD), 3.7 (2.0) months) in seropositive patients compared with seronegative patients (mean (SD), 1.9 (1.5) months, p=0.04). CONCLUSIONS: SARS-CoV-2 antibody response was decreased in patients with MS or NMO-SD treated with anti-CD20 therapies. Monitoring long-term risk of reinfection and specific vaccination strategies in this population may be warranted. TRIAL REGISTRATION NUMBER: NCT04568707.

Charting a global research strategy for progressive MS-An international progressive MS Alliance proposal.

BACKGROUND: Progressive forms of multiple sclerosis (MS) affect more than 1 million individuals globally. Recent approvals of ocrelizumab for primary progressive MS and siponimod for active secondary progressive MS have opened the therapeutic door, though results from early trials of neuroprotective agents have been mixed. The recent introduction of the term 'active' secondary progressive MS into the therapeutic lexicon has introduced potential confusion to disease description and thereby clinical management. OBJECTIVE: This paper reviews recent progress, highlights continued knowledge and proposes, on behalf of the International Progressive MS Alliance, a global research strategy for progressive MS. METHODS: Literature searches of PubMed between 2015 and May, 2021 were conducted using the search terms "progressive multiple sclerosis", "primary progressive multiple sclerosis", "secondary progressive MS". Proposed strategies were developed through a series of in-person and virtual meetings of the International Progressive MS Alliance Scientific Steering Committee. RESULTS: Sustaining and accelerating progress will require greater understanding of underlying mechanisms, identification of potential therapeutic targets, biomarker discovery and validation, and conduct of clinical trials with improved trial design. Encouraging developments in symptomatic and rehabilitative interventions are starting to address ongoing challenges experienced by people with progressive MS. CONCLUSION: We need to manage these challenges and realise the opportunities in the context of a global research strategy, which will improve quality of life for people with progressive MS.

Oligodendrocyte Secreted Factors Shape Hippocampal GABAergic Neuron Transcriptome and Physiology.

Oligodendrocytes form myelin for central nervous system axons and release factors which signal to neurons during myelination. Here, we ask how oligodendroglial factors influence hippocampal GABAergic neuron physiology. In mixed hippocampal cultures, GABAergic neurons fired action potentials (APs) of short duration and received high frequencies of excitatory synaptic events. In purified neuronal cultures without glial cells, GABAergic neuron excitability increased and the frequency of synaptic events decreased. These effects were largely reversed by adding oligodendrocyte conditioned medium (OCM). We compared the transcriptomic signature with the electrophysiological phenotype of single neurons in these three culture conditions. Genes expressed by single pyramidal or GABAergic neurons largely conformed to expected cell-type specific patterns. Multiple genes of GABAergic neurons were significantly downregulated by the transition from mixed cultures containing glial cells to purified neuronal cultures. Levels of these genes were restored by the addition of OCM to purified cultures. Clustering genes with similar changes in expression between different culture conditions revealed processes affected by oligodendroglial factors. Enriched genes are linked to roles in synapse assembly, AP generation, and transmembrane ion transport, including of zinc. These results provide new insight into the molecular targets by which oligodendrocytes influence neuron excitability and synaptic function.

Human papillomavirus lesions in 16 MS patients treated with fingolimod: Outcomes and vaccination.

Few cases of human papillomavirus (HPV) diseases have been reported in multiple sclerosis (MS) patients treated with fingolimod. We describe a case series of 16 MS patients (11 women, 5 men) developing HPV lesions after the onset of fingolimod, without previous HPV history. Fingolimod had to be discontinued in six patients. Six patients received vaccination for HPV, with good tolerance. Our report highlights that systematic HPV screening and discussion about HPV vaccination before fingolimod onset are crucial. In case of occurrence of HPV lesions during fingolimod treatment, a comprehensive workup of HPV disease is necessary, with discussion of HPV vaccination to prevent secondary lesions. Prevalence studies of HPV lesions are needed in MS patients with the different disease-modifying therapies.

A randomized study of natalizumab dosing regimens for relapsing-remitting multiple sclerosis.

BACKGROUND: REFINE was an exploratory, dose- and frequency-blinded, prospective, randomized, dose-ranging study in relapsing-remitting multiple sclerosis (RRMS) patients. OBJECTIVE: To examine the efficacy, safety, and tolerability of natalizumab administered via various regimens in RRMS patients. METHODS: Clinically stable RRMS patients previously treated with 300 mg natalizumab intravenously for ⩾12 months were randomized to one of six natalizumab regimens over 60 weeks: 300 mg administered intravenously or subcutaneously every 4 weeks (Q4W), 300 mg intravenously or subcutaneously every 12 weeks (Q12W), or 150 mg intravenously or subcutaneously Q12W. The primary endpoint was the mean cumulative number of combined unique active magnetic resonance imaging (MRI) lesions at week 60. RESULTS: In total, 290 patients were enrolled. All Q12W dosing arms were associated with increased clinical and MRI disease activity and closed early; ⩾39.5% of patients in each Q12W arm met rescue criteria. In the 300 mg intravenous and subcutaneous Q4 W arms, the mean cumulative number of combined unique active MRI lesions was 0.23 and 0.02, respectively; annualized relapse rates were 0.07 and 0.08, respectively; and trough natalizumab serum levels and α4-integrin saturation were comparable. CONCLUSION: Natalizumab 300 mg subcutaneous Q4W was comparable to 300 mg intravenous Q4W dosing with respect to efficacy, pharmacokinetics/pharmacodynamics, and safety.

Multiple sclerosis: Is there a risk of worsening after yellow fever vaccination?

BACKGROUND: Yellow fever vaccine (YFV) is not advised for multiple sclerosis (MS) patients because of the potential risk of post-vaccine relapses. OBJECTIVE: To assess the risk of relapsing-remitting multiple sclerosis (RR-MS) worsening after YFV. METHODS: Non-interventional observational retrospective, exposed/non-exposed cohort study nested in the French national cohort including MS. RESULTS: 128 RR-MS were included. The 1-year annualized relapse rate (ARR) following YFV did not differ between exposed: 0.219 (0.420) and non-exposed subjects: 0.208 (0.521) (p = 0.92). Time to first relapse was not different between groups (adjusted hazard ratio (HR) = 1.33; 95% confidence interval (CI) = 0.53-3.30, p = 0.54). CONCLUSION: These results suggest that YFV does not worsen the course of RR-MS.

An alternative mechanism of early nodal clustering and myelination onset in GABAergic neurons of the central nervous system.

In vertebrates, fast saltatory conduction along myelinated axons relies on the node of Ranvier. How nodes assemble on CNS neurons is not yet fully understood. We previously described that node-like clusters can form prior to myelin deposition in hippocampal GABAergic neurons and are associated with increased conduction velocity. Here, we used a live imaging approach to characterize the intrinsic mechanisms underlying the assembly of these clusters prior to myelination. We first demonstrated that their components can partially preassemble prior to membrane targeting and determined the molecular motors involved in their trafficking. We then demonstrated the key role of the protein ß2Nav for node-like clustering initiation. We further assessed the fate of these clusters when myelination proceeds. Our results shed light on the intrinsic mechanisms involved in node-like clustering prior to myelination and unravel a potential role of these clusters in node of Ranvier formation and in guiding myelination onset.

Highlights from the 2019 European Congress on Treatment and Research in Multiple Sclerosis (ECTRIMS 2019).

The 2019 ECTRIMS Congress, in Stockholm, has had record-breaking figures for both attendance and scientific production. There were 9361 participants from 100 different countries for a total of 1541 abstracts. Upon invitation of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) executive committee, the authors of this meeting report assessed abstracts from all poster and oral presentations for novelty, scientific quality and relevance for basic and clinical multiple sclerosis (MS) research. The objective of this report is to highlight a selection of basic, translational and clinical studies out of the many outstanding projects that were presented. Abstracts and references cited in our report were chosen at the discretion of the authors and all co-authors and the ECTRIMS executive committee agreed on the selection. In the event of discrepancies between the abstract and the uploaded poster or presentation, we aimed to present data derived from the poster or presentation. All abstracts are accessible through the ECTRIMS online library ( https://onlinelibrary.ectrimscongress.eu/ectrims/#!*menu=36*browseby=3*sortby=2*ce_id=160 ) and also published in this journal (Volume 25 Issue 2_suppl, September 2019; https://journals.sagepub.com/toc/msja/25/2_suppl ). A few additional references from the literature were added but were restricted to the ones that authors considered as absolutely required for an optimized understanding of the topics highlighted.

Outcomes of ileal conduit urinary diversion in patients with multiple sclerosis.

AIM: The objective of this study was to report the long-term outcomes and complications of patients with multiple sclerosis (MS) who underwent noncontinent urinary diversion to treat lower urinary tract symptoms (LUTS). MATERIAL AND METHODS: A retrospective study included all adult patients with MS who underwent an ileal conduit urinary diversion between 2000 and 2015. Early postoperative complications were reported as well as long-term complications, reoperation rates, and renal function. RESULTS: Overall, 91 patients were included. The surgery was indicated for refractory urinary incontinence (n = 73), renal failure (n = 8), major perineal skin ulcer due to urinary incontinence (n = 6), and recurrent urinary tract infections (n = 4). The median follow-up was 50 months (range, 3-158 months). A significant reduction (P < .05) of postoperative nonobstructive pyelonephritis rate was observed. There was no significant difference between preoperative and postoperative renal function (P = .32). Early postoperative complications were reported in 24 patients (26%): 4 Clavien I, 6 Clavien II, 9 Clavien III, 4 Clavien IV, and 1 Clavien V. Nine patients required reoperation for these complications (9.9%). Late complications were reported in 28 patients (30.8%): 8 ureteral anastomosis stenosis, 2 stoma stenosis, 2 incisional hernias, 6 kidney or ureteral lithiasis, and 10 pyelonephritis. Among them, 15 patients (16.5%) required reoperation for late complications. CONCLUSION: Noncontinent urinary diversion using ileal conduit appears to be an effective end-stage solution in MS patients. The perioperative morbidity rate of 26% and the late complication rate of 31% should be considered to better inform patients before the surgery.

Assessment of lesions on magnetic resonance imaging in multiple sclerosis: practical guidelines.

MRI has improved the diagnostic work-up of multiple sclerosis, but inappropriate image interpretation and application of MRI diagnostic criteria contribute to misdiagnosis. Some diseases, now recognized as conditions distinct from multiple sclerosis, may satisfy the MRI criteria for multiple sclerosis (e.g. neuromyelitis optica spectrum disorders, Susac syndrome), thus making the diagnosis of multiple sclerosis more challenging, especially if biomarker testing (such as serum anti-AQP4 antibodies) is not informative. Improvements in MRI technology contribute and promise to better define the typical features of multiple sclerosis lesions (e.g. juxtacortical and periventricular location, cortical involvement). Greater understanding of some key aspects of multiple sclerosis pathobiology has allowed the identification of characteristics more specific to multiple sclerosis (e.g. central vein sign, subpial demyelination and lesional rims), which are not included in the current multiple sclerosis diagnostic criteria. In this review, we provide the clinicians and researchers with a practical guide to enhance the proper recognition of multiple sclerosis lesions, including a thorough definition and illustration of typical MRI features, as well as a discussion of red flags suggestive of alternative diagnoses. We also discuss the possible place of emerging qualitative features of lesions which may become important in the near future.

Role of a Contactin multi-molecular complex secreted by oligodendrocytes in nodal protein clustering in the CNS.

The fast and reliable propagation of action potentials along myelinated fibers relies on the clustering of voltage-gated sodium channels at nodes of Ranvier. Axo-glial communication is required for assembly of nodal proteins in the central nervous system, yet the underlying mechanisms remain poorly understood. Oligodendrocytes are known to support node of Ranvier assembly through paranodal junction formation. In addition, the formation of early nodal protein clusters (or prenodes) along axons prior to myelination has been reported, and can be induced by oligodendrocyte conditioned medium (OCM). Our recent work on cultured hippocampal neurons showed that OCM-induced prenodes are associated with an increased conduction velocity (Freeman et al., 2015). We here unravel the nature of the oligodendroglial secreted factors. Mass spectrometry analysis of OCM identified several candidate proteins (i.e., Contactin-1, ChL1, NrCAM, Noelin2, RPTP/Phosphacan, and Tenascin-R). We show that Contactin-1 combined with RPTP/Phosphacan or Tenascin-R induces clusters of nodal proteins along hippocampal GABAergic axons. Furthermore, Contactin-1-immunodepleted OCM or OCM from Cntn1-null mice display significantly reduced clustering activity, that is restored by addition of soluble Contactin-1. Altogether, our results identify Contactin-1 secreted by oligodendrocytes as a novel factor that may influence early steps of nodal sodium channel cluster formation along specific axon populations.

Efficacy of rituximab in refractory RRMS.

OBJECTIVE: To investigate the efficacy of rituximab as rescue therapy in patients with relapsing-remitting multiple sclerosis (RRMS) and persistent disease activity confirmed by magnetic resonance imaging (MRI) despite immunosuppressive disease-modifying therapy (DMT). METHODS: In this observational nationwide retrospective multicenter study, we first identified 351 off-label rituximab-treated patients through a cohort of 15,984 RRMS patients. In this group, we identified patients with disease activity prior to rituximab confirmed by MRI (one or more new T2 lesion and/or gadolinium-enhancing lesion) despite immunosuppressive DMT (fingolimod, natalizumab, or mitoxantrone) with a follow-up after rituximab initiation longer than 6 months. Outcome data were collected from the French Observatory of Multiple Sclerosis (OFSEP) register and medical charts. RESULTS: A total of 50 patients were identified. Median rituximab treatment duration was 1.1 (0.5-6.4) year. Mean annualized relapse rate significantly decreased from 0.8 during last immunosuppressive DMT to 0.18 after rituximab ( p < 0.0001). While 72% of patients showed gadolinium-enhancing lesions on the last MRI performed during last immunosuppressive DMT, 8% of them showed gadolinium-enhancing lesions on the first MRI performed 6.1 (range 1.4-18.4) months after rituximab ( p < 0.0001). CONCLUSION: This study provides level IV evidence that rituximab reduces clinical and MRI disease activity in patients with active RRMS despite immunosuppressive DMT.

Dysregulation of energy metabolism in multiple sclerosis measured in vivo with diffusion-weighted spectroscopy.

OBJECTIVE: We employed diffusion-weighted magnetic resonance spectroscopy (DW-MRS), which allows to measure in vivo the diffusion properties of metabolites, to explore the functional neuro-axonal damage and the ongoing energetic dysregulation in multiple sclerosis (MS). METHODS: Twenty-five patients with MS and 18 healthy controls (HC) underwent conventional magnetic resonance imaging (MRI) and DW-MRS. The apparent diffusion coefficient (ADC) of total N-acetyl-aspartate (tNAA) and creatine-phosphocreatine (tCr) were measured in the parietal normal-appearing white matter (NAWM) and in the thalamic grey matter (TGM). Multiple regressions were used to compare metabolite ADCs between groups and to explore clinical correlations. RESULTS: In patients compared with HCs, we found a reduction in ADC(tNAA) in the TGM, reflecting functional and structural neuro-axonal damage, and in ADC(tCr) in both NAWM and TGM, possibly reflecting a reduction in energy supply in neurons and glial cells. Metabolite ADCs did not correlate with tissue atrophy, lesional volume or metabolite concentrations, while in TGM metabolite ADCs correlated with clinical scores. CONCLUSION: DW-MRS showed a reduction in tCr diffusivity in the normal-appearing brain of patients with MS, which might reflect a state of ongoing energy dysregulation affecting neurons and/or glial cells. Reversing this energy dysregulation before neuro-axonal degeneration arises may become a key objective in future neuroprotective strategies.

The Xenopus tadpole: An in vivo model to screen drugs favoring remyelination.

BACKGROUND: In multiple sclerosis, development of screening tools for remyelination-promoting molecules is timely. OBJECTIVE: A Xenopus transgenic line allowing conditional ablation of myelinating oligodendrocytes has been adapted for in vivo screening of remyelination-favoring molecules. METHODS: In this transgenic, the green fluorescent protein reporter is fused to E. coli nitroreductase and expressed specifically in myelinating oligodendrocytes. Nitroreductase converts the innocuous pro-drug metronidazole to a cytotoxin. Spontaneous remyelination occurs after metronidazole-induced demyelinating responses. As tadpoles are transparent, these events can be monitored in vivo and quantified. At the end of metronidazole-induced demyelination, tadpoles were screened in water containing the compounds tested. After 72 h, remyelination was assayed by counting numbers of oligodendrocytes per optic nerve. RESULTS: Among a battery of molecules tested, siponimod, a dual agonist of sphingosine-1-phosphate receptor 1 and 5, was among the most efficient favoring remyelination. Crispr/cas9 gene editing showed that the promyelinating effect of siponimod involves the sphingosine-1-phosphate receptor 5. CONCLUSION: This Xenopus transgenic line constitutes a simple in vivo screening platform for myelin repair therapeutics. We validated several known promyelinating compounds and demonstrated that the strong remyelinating efficacy of siponimod implicates the sphingosine-1-phosphate receptor 5.

ECTRIMS/EAN Guideline on the pharmacological treatment of people with multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a complex disease with new drugs becoming available in the past years. There is a need for a reference tool compiling current data to aid professionals in treatment decisions. OBJECTIVES: To develop an evidence-based clinical practice guideline for the pharmacological treatment of people with MS. METHODS: This guideline has been developed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology and following the updated EAN recommendations. Clinical questions were formulated in Patients-Intervention-Comparator-Outcome (PICO) format and outcomes were prioritized. The quality of evidence was rated into four categories according to the risk of bias. The recommendations with assigned strength (strong and weak) were formulated based on the quality of evidence and the risk-benefit balance. Consensus between the panelists was reached by use of the modified nominal group technique. RESULTS: A total of 10 questions were agreed, encompassing treatment efficacy, response criteria, strategies to address suboptimal response and safety concerns and treatment strategies in MS and pregnancy. The guideline takes into account all disease-modifying drugs approved by the European Medicine Agency (EMA) at the time of publication. A total of 21 recommendations were agreed by the guideline working group after three rounds of consensus. CONCLUSION: The present guideline will enable homogeneity of treatment decisions across Europe.