Time is myelin: early cortical myelin repair prevents atrophy and clinical progression in multiple sclerosis

Cortical myelin loss and repair in multiple sclerosis (MS) have been explored in neuropathological studies, but the impact of these processes on neurodegeneration and the irreversible clinical progression of the disease remains unknown. Here, we evaluated in vivo cortical demyelination and remyelination in a large cohort of people with all clinical phenotypes of MS followed up for 5 years using magnetization transfer imaging (MTI), a technique that has been shown to be sensitive to myelin content changes in the cortex. We investigated 140 people with MS (37 clinically isolated syndrome, 71 relapsing-MS, 32 progressive-MS), who were clinically assessed at baseline and after 5 years and, along with 84 healthy controls, underwent a 3 T-MRI protocol including MTI at baseline and after 1 year. Changes in cortical volume over the radiological follow-up were computed with a Jacobian integration method. Magnetization transfer ratio was employed to calculate for each patient an index of cortical demyelination at baseline and of dynamic cortical demyelination and remyelination over the follow-up period. The three indices of cortical myelin content change were heterogeneous across patients but did not significantly differ across clinical phenotypes or treatment groups. Cortical remyelination, which tended to fail in the regions closer to CSF (-11%, P < 0.001), was extensive in half of the cohort and occurred independently of age, disease duration and clinical phenotype. Higher indices of cortical dynamic demyelination (β = 0.23, P = 0.024) and lower indices of cortical remyelination (β = -0.18, P = 0.03) were significantly associated with greater cortical atrophy after 1 year, independently of age and MS phenotype. While the extent of cortical demyelination predicted a higher probability of clinical progression after 5 years in the entire cohort [odds ratio (OR) = 1.2; P = 0.043], the impact of cortical remyelination in reducing the risk of accumulating clinical disability after 5 years was significant only in the subgroup of patients with shorter disease duration and limited extent of demyelination in cortical regions (OR = 0.86, P = 0.015, area under the curve = 0.93). In this subgroup, a 30% increase in cortical remyelination nearly halved the risk of clinical progression at 5 years, independently of clinical relapses. Overall, our results highlight the critical role of cortical myelin dynamics in the cascade of events leading to neurodegeneration and to the subsequent accumulation of irreversible disability in MS. Our findings suggest that early-stage myelin repair compensating for cortical myelin loss has the potential to prevent neuro-axonal loss and its long-term irreversible clinical consequences in people with MS.

Association Between Anti-CD20 Therapies and COVID-19 Severity Among Patients With Relapsing-Remitting and Progressive Multiple Sclerosis

Importance

In patients with multiple sclerosis (MS), factors associated with severe COVID-19 include anti-CD20 therapies and neurologic disability, but it is still unclear whether these 2 variables are independently associated with severe COVID-19 or whether the association depends on MS clinical course.

Objective

To assess the association between anti-CD20 therapies and COVID-19 severity in patients with relapsing-remitting MS (RRMS) and progressive MS (PMS).

Design, Setting, and Participants

This multicenter, retrospective cohort study used data from the COVISEP study, which included patients with MS and COVID-19 from February 1, 2020, to June 30, 2022, at 46 French MS expert centers, general hospitals, and private neurology practices. Eligible patients with RRMS were those treated with high-efficacy MS therapy (ie, anti-CD20, fingolimod, or natalizumab), and eligible patients with PMS were those younger than 70 years with an Expanded Disability Status Scale (EDSS) score of 8 or lower. Patients were monitored from COVID-19 symptom onset until recovery or death.

Exposures

Current anti-CD20 therapy (ocrelizumab or rituximab).

Main Outcomes and Measures

The main outcome was severe COVID-19 (ie, hospitalization with any mode of oxygenation or death). All analyses were conducted separately in patients with RRMS and PMS using propensity score-weighted logistic regression. Subgroup analyses were performed according to COVID-19 vaccine status, sex, EDSS score, and age.

Results

A total of 1400 patients, 971 with RRMS (median age, 39.14 years [IQR, 31.38-46.80 years]; 737 [76.1%] female) and 429 with PMS (median age, 54.21 years [IQR, 48.42-60.14 years]; 250 [58.3%] female) were included in the study. A total of 418 patients with RRMS (43.0%) and 226 with PMS (52.7%) were treated with anti-CD20 therapies. In weighted analysis, 13.4% and 2.9% of patients with RRMS treated and not treated with anti-CD20 had severe COVID-19, respectively, and anti-CD20 treatment was associated with increased risk of severe COVID-19 (odds ratio [OR], 5.20; 95% CI, 2.78-9.71); this association persisted among vaccinated patients (7.0% vs 0.9%; OR, 8.85; 95% CI, 1.26-62.12). Among patients with PMS, 19.0% and 15.5% of patients treated and not treated with anti-CD20 had severe COVID-19, respectively, and there was no association between anti-CD20 treatment and severe COVID-19 (OR, 1.28; 95% CI, 0.76-2.16). In PMS subgroup analysis, anti-CD20 exposure interacted negatively with EDSS score (P = .009 for interaction) and age (P = .03 for interaction); anti-CD20 therapies were associated with risk of severe COVID-19 only in patients with less neurologic disability and younger patients with PMS.

Conclusions and Relevance

In this cohort study, risk of severe COVID-19 was higher in patients with PMS than in those with RRMS. Use of anti-CD20 therapies was associated with an increased risk of severe COVID-19 among patients with RRMS. In patients with PMS, there was no association between anti-CD20 therapies and risk of severe COVID-19.

Pregnancy and neuromyelitis optica spectrum disorders: 2022 recommendations from the French Multiple Sclerosis Society

BACKGROUND

In 2020, the French Multiple Sclerosis (MS) Society (SFSEP) decided to develop a national evidence-based consensus on pregnancy in MS. As neuromyelitis optica spectrum disorders (NMOSD) shares a series of commonalities with MS, but also some significant differences, specific recommendations had to be developed.

OBJECTIVES

To establish recommendations on pregnancy in women with NMOSD.

METHODS

The French Group for Recommendations in Multiple Sclerosis (France4MS) reviewed PubMed and universities databases (January 1975 through June 2021). The RAND/UCLA appropriateness method, which was developed to synthesise the scientific literature and expert opinions on health care topics, was used to reach a formal agreement. Fifty-six MS experts worked on the full-text review and initial wording of recommendations. A sub-group of nine NMOSD experts was dedicated to analysing available data on NMOSD. A group of 62 multidisciplinary healthcare specialists validated the final proposal of summarised evidence.

RESULTS

A strong agreement was reached for all 66 proposed recommendations. They cover diverse topics, such as pregnancy planning, follow-up during pregnancy and postpartum, delivery routes, loco-regional analgesia or anaesthesia, prevention of postpartum relapses, breastfeeding, vaccinations, reproductive assistance, management of relapses, and disease-modifying treatments.

CONCLUSION

Physicians and patients should be aware of the new and specific evidence-based recommendations of the French MS Society for pregnancy in women with NMOSD. They should help harmonise counselling and treatment practise, allowing for better individualised choices.

Pregnancy and multiple sclerosis: 2022 recommendations from the French multiple sclerosis society

OBJECTIVE

The objective of this study was to develop evidence-based recommendations on pregnancy management for persons with multiple sclerosis (MS).

BACKGROUND

MS typically affects young women in their childbearing years. Increasing evidence is available to inform questions raised by MS patients and health professionals about pregnancy issues.

METHODS

The French Group for Recommendations in Multiple Sclerosis (France4MS) reviewed PubMed and university databases (January 1975 through June 2021). The RAND/UCLA appropriateness method was developed to synthesise the scientific literature and expert opinions on healthcare topics; it was used to reach a formal agreement. Fifty-six MS experts worked on the full-text review and initial wording of recommendations. A group of 62 multidisciplinary healthcare specialists validated the final proposal of summarised evidence.

RESULTS

A strong agreement was reached for all 104 proposed recommendations. They cover diverse topics, such as pregnancy planning, follow-up during pregnancy and postpartum, delivery routes, locoregional analgesia or anaesthesia, prevention of postpartum relapses, breastfeeding, vaccinations, reproductive assistance, management of relapses and disease-modifying treatments.

CONCLUSION

The 2022 recommendations of the French MS society should be helpful to harmonise counselling and treatment practice for pregnancy in persons with MS, allowing for better and individualised choices.

The risk of infections for multiple sclerosis and neuromyelitis optica spectrum disorder disease-modifying treatments: Eighth European Committee for Treatment and Research in Multiple Sclerosis Focused Workshop Review. April 2021

Over the recent years, the treatment of multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) has evolved very rapidly and a large number of disease-modifying treatments (DMTs) are now available. However, most DMTs are associated with adverse events, the most frequent of which being infections. Consideration of all DMT-associated risks facilitates development of risk mitigation strategies. An international focused workshop with expert-led discussions was sponsored by the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) and was held in April 2021 to review our current knowledge about the risk of infections associated with the use of DMTs for people with MS and NMOSD and corresponding risk mitigation strategies. The workshop addressed DMT-associated infections in specific populations, such as children and pregnant women with MS, or people with MS who have other comorbidities or live in regions with an exceptionally high infection burden. Finally, we reviewed the topic of DMT-associated infectious risks in the context of the current SARS-CoV-2 pandemic. Herein, we summarize available evidence and identify gaps in knowledge which justify further research.

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.

Association of Central Hypersomnia and Fatigue in Patients With Multiple Sclerosis: A Polysomnographic Study

OBJECTIVE

To evaluate sleepiness and central hypersomnia in multiple sclerosis (MS)-associated fatigue, we performed long-term polysomnography in patients with MS and healthy controls.

METHODS

Patients with MS and healthy controls completed questionnaires on sleep, fatigue, sleepiness, and depression. They underwent nocturnal polysomnography, multiple sleep latency tests, and bed rest 24-hour polysomnography. Patients were divided into 3 groups (fatigue and sleepiness, fatigue and no sleepiness, neither fatigue nor sleepiness).

RESULTS

Among 44 patients with MS, 19 (43.2%) had fatigue and sleepiness, 15 (34%) had only fatigue, and 10 (22.7%) had neither fatigue nor sleepiness. Compared to 24 controls, patients with fatigue and sleepiness had higher REM sleep percentages (median [interquartile range] 20.5% [19.6-24.7] vs 18.1% [12.6-20.6]), lower arousal indexes (12.7 [7.5-17.0] vs 22.4 [14.3-34.4]), and shorter daytime mean sleep latencies (8.6 [6.3-14.3] vs 16.6 [12.6-19.5] min). Restless leg syndrome, periodic leg movements, and sleep apnea had similar frequencies between groups. Central hypersomnia was found in 10 (53%) patients with fatigue and sleepiness (narcolepsy type 2, n = 2), in 2 (13%) patients with fatigue only, and in 3 (30%) patients with neither fatigue nor sleepiness. Patients with central hypersomnia were younger and sleepier than those without hypersomnia, but had similar levels of fatigue, disability, depression, cognitive performance, and frequencies of the human leukocyte antigen DQB1*0602 genotype. The severity of fatigue increased with higher depression scores, higher sleepiness severity, and lower sleep efficacy.

CONCLUSION

Central hypersomnias are frequent in MS when fatigue and sleepiness are present. Screening them through polysomnography studies is recommended.

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 β2Na_v 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.

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.

Superficial siderosis of the central nervous system: a rare cause of dementia with therapeutic consequences

A 75-year-old patient was evaluated for dementia. His past medical history included an ischaemic cardiomyopathy treated with aspirin daily. His neurological examination showed mild ataxia syndrome and central deafness. The neuropsychological examination did not suggest Alzheimer's disease. No specific aetiology was found from biological investigations, but MRI scans revealed a superficial siderosis, which was further confirmed with CSF exams. This case highlights the interest of MRI with echo-gradient-T2 weighted sequences in patients investigated for memory disorders. Once the diagnosis is known, specific preventive measures have to be taken: searching for a treatable source of bleeding and the interruption of antiplatelet aggregation or anticoagulant treatments.