Teriflunomide Promotes Blood-Brain Barrier Integrity by Upregulating Claudin-1 via the Wnt/β-catenin Signaling Pathway in Multiple Sclerosis

The blood-brain barrier (BBB) and tight junction (TJ) proteins maintain the homeostasis of the central nervous system (CNS). The dysfunction of BBB allows peripheral T cells infiltration into CNS and contributes to the pathophysiology of multiple sclerosis (MS). Teriflunomide is an approved drug for the treatment of MS by suppressing lymphocytes proliferation. However, whether teriflunomide has a protective effect on BBB in MS is not understood. We found that teriflunomide restored the injured BBB in the EAE model. Furthermore, teriflunomide treatment over 6 months improved BBB permeability and reduced peripheral leakage of CNS proteins in MS patients. Teriflunomide increased human brain microvascular endothelial cell (HBMEC) viability and promoted BBB integrity in an in vitro cell model. The TJ protein claudin-1 was upregulated by teriflunomide and responsible for the protective effect on BBB. Furthermore, RNA sequencing revealed that the Wnt signaling pathway was affected by teriflunomide. The activation of Wnt signaling pathway increased claudin-1 expression and reduced BBB damage in cell model and EAE rats. Our study demonstrated that teriflunomide upregulated the expression of the tight junction protein claudin-1 in endothelial cells and promoted the integrity of BBB through Wnt signaling pathway.

The weighted cumulative exposure method and its application to pharmacoepidemiology: A narrative review

PURPOSE

The weighted cumulative exposure (WCE) method has been used in a number of fields including pharmacoepidemiology where it can account for intensity, duration and timing of exposures on the risk of an outcome. The method uses a data driven approach with flexible cubic B-splines to assign weights to past doses and select an aetiologically appropriate time window. Predictions of risk are possible for common exposure patterns encountered in real-world studies. The purpose of this study was to describe applications of the WCE method to pharmacoepidemiology and assess the strengths and limitations of the method.

METHOD

A literature search was undertaken to find studies applying the WCE method to the study of medicines. Articles published in PubMed using the search term 'weighted cumulative exposure' and articles citing Sylvestre et al. (2009) in Google Scholar or Scopus up to March 2023 were subsequently reviewed. Articles were selected based on title and review of abstracts.

RESULTS

Seventeen clinical applications using the data-driven WCE method with flexible cubic splines were identified in the review. These included 3 case-control studies and 14 cohort studies, of which 12 were analysed with Cox proportional hazards models and 2 with logistic regression. Thirteen studies used time windows of 1 year or longer. Of 11 studies which compared conventional models with the WCE method, 10 (91%) studies found a better fit with WCE models while one had an equivalent fit. The freely available 'WCE' software package has facilitated the applications of the WCE method with flexible cubic splines.

CONCLUSIONS

The WCE method allows additional insights into the effect of cumulative exposure on outcomes, including the timing and intensity (dose) of the exposure on the risk. The flexibility of the method is particularly well suited to studies with long-term exposures that vary over time or where the current risk of an event is affected by how far the exposure is in the past, which is difficult to model with conventional definitions of exposure. Interpretation of the results can be more complex than for conventional models and would be facilitated by a standardised reporting framework.

Economic burden of multiple sclerosis in the United States: A systematic literature review

BACKGROUND

Multiple sclerosis (MS) is chronic progressive disease that poses a significant economic burden to patients and health care systems in the United States. We conducted a systematic literature review to provide up-to-date insights on the economic burden of MS in the United States.

OBJECTIVE

To comprehensively review and summarize the latest published evidence on the economic burden of MS with a focus on cost, resource use, and work productivity.

METHODS

A systematic literature search was conducted using the Embase and Medline databases to identify studies, published between January 2011 and July 2022, reporting cost, resource use, or work productivity outcomes among people with MS in the United States. Clinical trials, economic modeling studies, and review articles were excluded. Details of eligible studies, including study design, patient population, and study outcomes for the overall population, as well as subgroups of interest, were extracted and summarized qualitatively.

RESULTS

Overall, 65 studies reporting cost, resource use, or work productivity data were included with majority of studies using claims data. The direct costs associated with MS ranged from $16,614 (2006) to $72,744 (2017) per patient per year with diseasemodifying therapies (DMTs) being the major cost contributors accounting for 43%-78%. The indirect costs reported ranged from $9,122 (2017) to $30,601 (2011) per patient per year with absenteeism, early retirement, and informal care being the key drivers for indirect costs. Costs, resource use, and work impairment were significantly higher for patients with severe disability compared with those with mild disability. Pharmacy costs were the major cost drivers in patients with mild, moderate, and severe disability. Similarly, patients with relapses incurred significantly higher costs, resource use, and work impairment compared with those without relapses. Additional hospitalization charges were the major driver of higher costs in patients who experienced relapses compared with those without relapses.

CONCLUSIONS

Direct costs, particularly DMTs, appear to be the major cost drivers for people with MS in the United States. Availability of lower-cost therapies may considerably decrease the economic burden on these patients and the health care systems. Future research focusing on indirect costs, intangible costs, and their contributors would contribute to further understanding of economic burden to avoid underestimation of the financial burden experienced by the patients.

The association between disability progression, relapses, and treatment in early relapse onset MS: an observational, multi-centre, longitudinal cohort study

The indirect contribution of multiple sclerosis (MS) relapses to disability worsening outcomes, and vice-versa, remains unclear. Disease modifying therapies (DMTs) are potential modulators of this association. Understanding how these endo-phenotypes interact may provide insights into disease pathogenesis and treatment practice in relapse-onset MS (ROMS). Utilising a unique, prospectively collected clinical data from a longitudinal cohort of 279 first demyelinating event cases followed for up to 15 years post-onset, we examined indirect associations between relapses and treatment and the risk of disability worsening, and vice-versa. Indirect association parameters were estimated using joint models for longitudinal and survival data. Early relapses within 2.5 years of MS onset predicted early disability worsening outcomes (HR = 3.45, C.I 2.29-3.61) per relapse, but did not contribute to long-term disability worsening thereinafter (HR = 0.21, C.I 0.15-0.28). Conversely, disability worsening outcomes significantly contributed to relapse risk each year (HR = 2.96, C.I 2.91-3.02), and persisted over time (HR = 3.34, C.I 2.90-3.86), regardless of DMT treatments. The duration of DMTs significantly reduced the hazards of relapses (1st-line DMTs: HR = 0.68, C.I 0.58-0.79; 3rd-line DMTs: HR = 0.37, C.I 0.32-0.44) and disability worsening events (1st-line DMTs: HR = 0.74, C.I 0.69-0.79; 3rd-line DMTs: HR = 0.90, C.I 0.85-0.95), respectively. Results from time-dynamic survival probabilities further revealed individuals having higher risk of future relapses and disability worsening outcomes, respectively. The study provided evidence that in ROMS, relapses accrued within 2.5 years of MS onset are strong indicators of disability worsening outcomes, but late relapses accrued 2.5 years post onset are not overt risk factors for further disability worsening. In contrast, disability worsening outcomes are strong positive predictors of current and subsequent relapse risk. Long-term DMT use and older age strongly influence the individual outcomes and their associations.

Thinking outside the box: non-canonical targets in multiple sclerosis

Multiple sclerosis (MS) is an immune-mediated disease of the central nervous system that causes demyelination, axonal degeneration and astrogliosis, resulting in progressive neurological disability. Fuelled by an evolving understanding of MS immunopathogenesis, the range of available immunotherapies for clinical use has expanded over the past two decades. However, MS remains an incurable disease and even targeted immunotherapies often fail to control insidious disease progression, indicating the need for new and exceptional therapeutic options beyond the established immunological landscape. In this Review, we highlight such non-canonical targets in preclinical MS research with a focus on five highly promising areas: oligodendrocytes; the blood-brain barrier; metabolites and cellular metabolism; the coagulation system; and tolerance induction. Recent findings in these areas may guide the field towards novel targets for future therapeutic approaches in MS.

Disability Progression in Multiple Sclerosis Patients using Early First-line Treatments

BACKGROUND

Therapeutic management of relapsing-remitting multiple sclerosis (RRMS) has evolved towards early treatment. The objective was to assess the impact of early treatment initiation on disability progression among RRMS first-line treated patients.

METHODS

This study included all incident RRMS cases starting interferon or glatiramer acetate for the first time from 1996/01/01 to 2012/31/12 (N=5,279) from ten MS expert OFSEP centers (Observatoire Français de la Sclérose en Plaques). The delay from treatment start to attain an irreversible Expanded Disability Status Scale score of 3.0 were compared between "Early" group (N= 1,882; treated within 12 months following MS clinical onset) and "Later" group using propensity score weighted Kaplan-Meier methods, overall and stratified by age.

RESULTS

Overall, the restricted mean time before reaching EDSS 3.0 (RMST) from treatment start was 11 years and two months for patients treated within the year following MS clinical onset and 10 years and seven months for patients treated later. Thus, early treated patients gained 7 months (95% CI: [4-11] months) in the time to reach EDSS 3.0 compared to patients treated later (treatment start delayed by 28 months). The difference in RMST was respectively six months (95% CI: [1-10] months) and 14 months (95% CI: [4-24] months) in the "≤40 years" age group and in the ">40 years" age group, in favour of early group. .

CONCLUSIONS

Early treatment initiation resulted in a significant reduction of disability progression among patients with RRMS, and also among older patients.

SARS-CoV-2 Infection and Vaccination Outcomes in Multiple Sclerosis

Background:

The effects of the SARs-CoV-2 vaccination and infection on clinical outcomes, including relapse risk, have been insufficiently explored in people with MS (PwMS). The objectives of this study were to determine the incidence of new neurologic symptoms or symptom recrudescence among PwMS who received the SARs-CoV-2 vaccine, characterize outcomes following SARs-CoV-2 infection, and assess MS-specific determinants of vaccine hesitancy.

Methods:

Online surveys that assessed incidence and severity of SARs-CoV-2 infection, vaccination status/type, reasons for vaccine deferral, and post-vaccination symptoms were administered to PwMS. Medical charts were reviewed for consenting respondents. Associations between infection, post-vaccination outcomes, and clinical characteristics were compared using chi-square tests, 2-sample T-tests, and adjusted logistic regression models.

Results:

n=292 of 333 respondents were vaccinated, of which 58% reported post-vaccination side effects, most commonly among mRNA vaccine recipients (p=0.02), younger patients (p<0.01), and relapsing-remitting MS (p=0.03). Twelve percent endorsed recrudescence of existing MS symptoms, while 3% endorsed new neurologic symptoms post-vaccination. N=62 reported SARs-CoV-2 infection since the start of the pandemic, more frequent in younger individuals (1-year OR=0.958, 10-year OR=0.649, p<0.01). Neither DMT nor B-cell therapies specifically were associated with vaccine side effects, neurologic symptoms, or SARs-CoV-2 infection. Twenty-one percent of unvaccinated cited a desire for provider guidance prior to vaccination.

Conclusion:

Our findings provide new data to suggest that among PwMS who received SARs-CoV-2 vaccination, clinical disease worsening is rare and mostly associated with symptom recrudescence, as opposed to new relapses. Post-vaccination side effects may occur more often among mRNA vaccine recipients, and in younger individuals.

Beyond McDonald: updated perspectives on MRI diagnosis of multiple sclerosis

INTRODUCTION

Magnetic resonance imaging (MRI) is an essential paraclinical test to establish an accurate and early diagnosis of multiple sclerosis (MS), which is based on the application of the McDonald criteria.

AREAS COVERED

The objective of this article is to analyze, based on publicly available database since the publication of the 2017 McDonald diagnostic criteria, the clinical impact of these criteria, to discuss the potential inclusion within these criteria of the optic nerve to demonstrate dissemination in space, and to guide the acquisition and interpretation of MRI scans for diagnostic purposes. Finally, the authors will review emerging MRI features that could improve the specificity of MRI in the diagnosis of MS and consequently minimize the misdiagnosis of this disease.

EXPERT OPINION

Although the optic nerve has not been included as one of the topographies required to demonstrate demyelinating lesion disseminated in space in the 2017 McDonald criteria, new studies seem to show some improvement in the sensitivity of these criteria when this topography is considered. New radiological findings such as the central vein sign and iron rims, should be considered within the typical MRI features of this disease with the objective of minimizing MRI-based diagnostic errors.