Effect of teriflunomide on gray and white matter brain pathology in multiple sclerosis using volumetric and diffusion-tensor imaging MRI measures

Dynamic Changes in Long-Standing Multiple Sclerosis Revealed by Longitudinal Structural Network Analysis Using Diffusion Tensor Imaging

BACKGROUND AND PURPOSE

DTI can be used to derive conventional diffusion measurements, which can measure WM abnormalities in multiple sclerosis. DTI can also be used to construct structural brain networks and derive network measurements. However, few studies have compared their sensitivity in detecting brain alterations, especially in longitudinal studies. Therefore, in this study, we aimed to determine which type of measurement is more sensitive in tracking the dynamic changes over time in MS.

MATERIALS AND METHODS

Eighteen patients with MS were recruited at baseline and followed up at 6 and 12 months. All patients underwent MR imaging and clinical evaluation at 3 time points. Diffusion and network measurements were derived, and their brain changes were evaluated.

RESULTS

None of the conventional DTI measurements displayed statistically significant changes during the follow-up period; however, the nodal degree, nodal efficiency, and nodal path length of the left middle frontal gyrus and bilateral inferior frontal gyrus, opercular part showed significant longitudinal changes between baseline and at 12 months, respectively.

CONCLUSIONS

The nodal degree, nodal efficiency, and nodal path length of the left middle frontal gyrus and bilateral inferior frontal gyrus, opercular part may be used to monitor brain changes over time in MS.

Patterns of brain atrophy in recently-diagnosed relapsing-remitting multiple sclerosis

Recurrent neuroinflammation in relapsing-remitting MS (RRMS) is thought to lead to neurodegeneration, resulting in progressive disability. Repeated magnetic resonance imaging (MRI) of the brain provides non-invasive measures of atrophy over time, a key marker of neurodegeneration. This study investigates regional neurodegeneration of the brain in recently-diagnosed RRMS using volumetry and voxel-based morphometry (VBM). RRMS patients (N = 354) underwent 3T structural MRI <6 months after diagnosis and 1-year follow-up, as part of the Scottish multicentre 'FutureMS' study. MRI data were processed using FreeSurfer to derive volumetrics, and FSL for VBM (grey matter (GM) only), to establish regional patterns of change in GM and normal-appearing white matter (NAWM) over time throughout the brain. Volumetric analyses showed a decrease over time (q<0.05) in bilateral cortical GM and NAWM, cerebellar GM, brainstem, amygdala, basal ganglia, hippocampus, accumbens, thalamus and ventral diencephalon. Additionally, NAWM and GM volume decreased respectively in the following cortical regions, frontal: 14 out of 26 regions and 16/26; temporal: 18/18 and 15/18; parietal: 14/14 and 11/14; occipital: 7/8 and 8/8. Left GM and NAWM asymmetry was observed in the frontal lobe. GM VBM analysis showed three major clusters of decrease over time: 1) temporal and subcortical areas, 2) cerebellum, 3) anterior cingulum and supplementary motor cortex; and four smaller clusters within the occipital lobe. Widespread GM and NAWM atrophy was observed in this large recently-diagnosed RRMS cohort, particularly in the brainstem, cerebellar GM, and subcortical and occipital-temporal regions; indicative of neurodegeneration across tissue types, and in accord with limited previous studies in early disease. Volumetric and VBM results emphasise different features of longitudinal lobar and loco-regional change, however identify consistent atrophy patterns across individuals. Atrophy measures targeted to specific brain regions may provide improved markers of neurodegeneration, and potential future imaging stratifiers and endpoints for clinical decision making and therapeutic trials.

Effect of Lymphaticovenous Anastomosis on Muscle Edema, Limb, and Subfascial Volume in Lower Limb Lymphedema: MRI Studies

BACKGROUND

Although satisfactory volume reduction in secondary unilateral lower limb lymphedema after lymphaticovenous anastomosis (LVA) in the affected limb has been well reported, alleviation of muscle edema and the impact of LVA on the contralateral limb have not been investigated.

STUDY DESIGN

This retrospective cohort study enrolled patients who underwent supermicrosurgical LVA between November 2015 and January 2017. Pre- and post-LVA muscle edema were assessed using fractional anisotropy (FA) and apparent diffusion coefficient (ADC). The primary endpoint was changes in limb/subfascial volume assessed with magnetic resonance volumetry at least 6 months after LVA.

RESULTS

Twenty-one patients were enrolled in this study. Significant percentage reductions in post-LVA muscle edema were found in the affected thigh (83.6% [interquartile range = range of Q1 to Q3; 29.8-137.1] [FA], 53.3% [27.0-78.4] [ADC]) as well as limb (21.7% [4.4-26.5]) and subfascial (18.7% [10.7-39.1]) volumes. Similar findings were noted in the affected lower leg: 71.8% [44.0-100.1] (FA), 59.1% [45.8-91.2] (ADC), 21.2% [6.8-38.2], and 28.2% [8.5-44.8], respectively (all p < 0.001). Significant alleviation of muscle edema was also evident in the contralateral limbs (thigh: 25.1% [20.4-57.5] [FA]; 10.7% [6.6-17.7] [ADC]; lower leg: 47.1% [35.0-62.8] [FA]; 14.6% [6.5-22.1] [ADC]; both p < 0.001), despite no statistically significant difference in limb and subfascial volumes.

CONCLUSIONS

Our study found significant reductions in muscle edema and limb/subfascial volumes in the affected limb after LVA. Our findings regarding edema in the contralateral limb were consistent with possible lymphedema-associated systemic influence on the unaffected limb, which could be surgically relieved.

Real-world effectiveness and safety profile of teriflunomide in the management of multiple sclerosis in the Gulf Cooperation Council countries: An expert consensus narrative review

Background

The prevalence of multiple sclerosis (MS) is increasing in Gulf Cooperation Council (GCC) countries. Multiple sclerosis contributes to significant burden on patients and caregivers. The pharmacological treatment in MS involves treating acute exacerbations and preventing relapses and disability progression using disease-modifying therapies. Clinical evidence suggests that teriflunomide is one of the therapeutic choices for patients with relapsing–remitting MS (RRMS). However, genetic and cultural differences across different regions may contribute to variations in drug use. Therefore, it is necessary to consider real-world evidence for teriflunomide usage in GCC countries.

Methods

An expert group for MS gathered from GCC countries in December 2020. The consensus highlighting role of teriflunomide in MS management has been developed using clinical experiences and evidence-based approach.

Results

The expert-recommended patient profile for teriflunomide usage includes individuals aged 18 years and above, both men and women (on effective contraceptives) with clinically isolated syndrome or RRMS. The factors considered were cost-effectiveness of the drug, patient preference, adherence, monitoring, established safety profile, and coronavirus disease 2019 status.

Conclusion

Expert recommendations based on their clinical experience will be more helpful to clinicians in clinical settings regarding the usage of teriflunomide and provide valuable insights applicable in day-to-day practice.

Fingolimod treatment reverses signs of diffuse white matter damage in multiple sclerosis: A pilot study

BACKGROUND

In multiple sclerosis (MS) diffuse normal appearing white matter (NAWM) damage may drive chronic worsening independent of relapse activity. Diffusion tensor imaging (DTI) is a nonconventional MRI technique that can be used to assess microstructural alterations in myelin and axons. The aim of our study was to investigate the effect of six months fingolimod treatment on the integrity of entire and segmented NAWM in patients with relapsing-remitting multiple sclerosis (RRMS).

METHODS

Ten RRMS patients initiating fingolimod treatment were included in the study. Patients underwent 3 T MRI including diffusion tensor sequences at baseline before the initiation of treatment and at six months. The mean values for fractional anisotropy (FA), and mean, radial and axial diffusivities (MD, RD and AD) were calculated within the whole NAWM and in six segmented sub-regions of NAWM (frontal, parietal, temporal, occipital, cingulate and deep NAWM). Clinical characteristics, Expanded Disability Status Scale (EDSS) and volumetric MRI data were also evaluated.

RESULTS

In the cingulate NAWM FA was increased and RD was decreased significantly at six months compared to baseline (0.462 vs. 0.472, P = 0.027 and 0.000646 vs. 0.000634, P = 0.041, respectively), indicating improvements in myelin and axonal integrity following fingolimod treatment, whereas there were no alterations in cingulate MD or AD. Cingulate and temporal FA and RD correlated with T2 lesion volume percentage of cingulate and temporal areas. EDSS change correlated with change of the whole NAWM AD.

CONCLUSIONS

Increased FA and decreased RD in the cingulate NAWM might suggest microstructural fingolimod-induced improvements in the normal appearing cingulate white matter. Our results support the concept that DTI can be used as a marker of diffuse neuronal damage also in interventional settings.

Slowing of brain atrophy with teriflunomide and delayed conversion to clinically definite MS

Background:

We explored the effect of teriflunomide on cortical gray matter (CGM) and whole brain (WB) atrophy in patients with clinically isolated syndrome (CIS) from the phase III TOPIC study and assessed the relationship between atrophy and risk of conversion to clinically definite MS (CDMS).

Methods:

Patients (per McDonald 2005 criteria) were randomized 1:1:1 to placebo, teriflunomide 7 mg, or teriflunomide 14 mg for ⩽108 weeks (core study). In the extension, teriflunomide-treated patients maintained their original dose; placebo-treated patients were re-randomized 1:1 to teriflunomide 7 mg or 14 mg. Brain volume was assessed during years 1–2.

Results:

Teriflunomide 14 mg significantly slowed annualized CGM and WB atrophy versus placebo during years 1–2 [percent reduction: month 12, 61.4% (CGM; p = 0.0359) and 28.6% (WB; p = 0.0286); month 24, 40.2% (CGM; p = 0.0416) and 43.0% (WB; p < 0.0001)]. For every 1% decrease in CGM or WB volume during years 1–2, risk of CDMS conversion increased by 14.5% (p = 0.0004) and 47.3% (p < 0.0001) during years 1–2, respectively, and 6.6% (p = 0.0570) and 35.9% (p = 0.0250) during years 1–5. In patients with the least (bottom quartile) versus most (top quartile) atrophy during years 1–2, risk of CDMS conversion was reduced by 58% (CGM; p = 0.0024) and 58% (WB; p = 0.0028) during years 1–2, and 42% (CGM; p = 0.0138) and 29% (WB; p = 0.1912) during years 1–5.

Conclusion:

These findings support the clinical relevance of CGM and WB atrophy and early intervention with teriflunomide in CIS.

Temporal Dynamics of Diffusion Metrics in Early Multiple Sclerosis and Clinically Isolated Syndrome: A 2-Year Follow-Up Tract-Based Spatial Statistics Study

Background: Tract-based spatial statistics (TBSS) is suitable for the assessment of voxel-wise changes in fiber integrity in WM tracts in the entire brain. Longitudinal TBSS analyses of early multiple sclerosis (MS) using 3 Tesla magnetic resonance imaging (MRI) are not common. Objective: To characterize microstructural WM alterations at initial diagnosis in clinically isolated syndrome (CIS) and early MS at baseline and longitudinally over 2 years. Methods: DTI (Diffusion tensor imaging) at 3 Tesla was used to evaluate 106 therapy-naive patients with CIS or definite MS at baseline and at 1-year (N = 83) and 2-year (N = 43) follow-up compared to healthy controls (HC, N = 49). TBSS was used for voxel-wise analyses of the DTI indices of fractional anisotropy (FA) and radial, mean, and axial diffusivity (RD, MD, AD) for cross-sectional and longitudinal comparisons. Mean values of FA, RD, and cluster voxel numbers were extracted from significant clusters using an atlas-based approach. Correlations with disability (EDSS) were calculated for FA and RD changes related to affected brain regions. Results: Reductions in FA compared to HC were found at baseline in patients with CIS and RRMS and involved most supra- and infratentorial WM tracts. In the cerebellum and cerebral peduncles, these changes negatively correlated with EDSS after 2 years. FA changes in patients with CIS and RRMS evolved in the second year, particularly in the descending projection pathways and the cerebellum, and were significantly associated with EDSS. RD alterations compared to HC were undetectable in patients at baseline but were observed after 1 year and were exacerbated during the second year in all major supratentorial WM tracts, the corpus callosum, and the cerebellum. FA did not change between baseline and year 1 follow-up, but longitudinal investigation between the first and second year revealed combined dynamic FA and RD changes in the corpus callosum and corona radiata. Conclusion: TBSS of diffusion metrics at initial diagnosis and at 2-year follow-up showed microstructural WM pathology and associations between FA reduction and future disability, respectively. Combined longitudinal changes in FA and RD occurred in specific structures, where RD increases likely reflected progressing axonal degeneration. The distinct temporal dynamics of FA and RD, implying constancy during the first year, supports early therapeutic intervention for CIS and RRMS.

Teriflunomide's effect on humoral response to Epstein-Barr virus and development of cortical gray matter pathology in multiple sclerosis

BACKGROUND

Teriflunomide has been shown to slow cortical gray matter (GM) atrophy in patients with multiple sclerosis (MS). Previous work showed that higher levels of Epstein-Barr virus (EBV) are associated with greater development of cortical pathology in MS.

OBJECTIVES

To investigate whether the effect of teriflunomide on cortical volume loss in relapsing MS patients may be associated with the change in humoral response to EBV.

METHODS

This was a prospective, observational, single-blinded, longitudinal study of 30 relapsing MS patients, who started treatment with teriflunomide, and 20 age- and sex-matched healthy controls (HCs). Subjects were assessed at baseline, 6 and 12 months with clinical, MRI and EBV examinations. MRI outcomes included percent changes in cortical, GM, deep GM and whole brain volumes. Serum samples were analyzed for IgG antibodies titers against EBV viral capsid antigen (VCA) and nuclear antigen-1 (EBNA-1).

RESULTS

There were no significant differences in anti-VCA and anti-EBNA-1 IgG titers between MS patients and HC at baseline. However, over the 12-month follow-up, MS patients experienced a greater decrease in anti-EBNA-1 (-35.1, p = .003) and anti-VCA (-15.9, p = .05) IgG titers, whereas no significant changes were observed in HCs (-3.7 and -1.6, respectively). MS patients who showed the highest decrease in anti-EBV VCA and EBNA-1 IgG titers from baseline to follow-up, developed less cortical (p < .001 and p = .02) and GM volume loss (p = .004 for both), respectively.

CONCLUSIONS

Teriflunomide's effect on slowing cortical and GM volume loss may be mediated by its effect on altering humoral response to EBV.

Effect of Teriflunomide and Dimethyl Fumarate on Cortical Atrophy and Leptomeningeal Inflammation in Multiple Sclerosis: A Retrospective, Observational, Case-Control Pilot Study

Background: Pathologic changes in cortical gray matter (GM) and leptomeninges contribute to disability worsening in patients with multiple sclerosis (MS), but there is little evidence whether disease-modifying treatments can slow down cortical pathology in MS. Objectives: To investigate the effect of teriflunomide (TFM) and dimethyl fumarate (DMF) in reducing cortical pathology, as determined by percentage cortical volume change (PCVC) and leptomeningeal contrast enhancement (LMCE) on MRI. Methods: This was a retrospective, single-center, observational study that selected 60 TFM- and 60 DMF-treated MS patients over 24 months. Results: TFM had a lower rate of PCVC compared to DMF over 24 months (−0.2% vs. −2.94%, p = 0.004). Similar results were observed for percentage GM volume change over 0–12 (p = 0.044) and 0–24 (−0.44% vs. −3.12%, p = 0.015) months. No significant differences were found between the TFM and DMF groups in the frequency and number of LMCE foci over the follow-up. TFM showed a numerically lower rate of whole brain atrophy over 24 months (p = 0.077), compared to DMF. No significant clinical or MRI lesion differences between TFM and DMF were detected over follow-up. Conclusions: These findings suggest that TFM has a superior effect on the preservation of cortical GM volume, compared to DMF.

The role of Epstein-Barr virus in multiple sclerosis: from molecular pathophysiology to in vivo imaging

Multiple sclerosis (MS) is a disease of the central nervous system characterized by inflammation, demyelination, and neuronal damage. Environmental and genetic factors are associated with the risk of developing MS, but the exact cause still remains unidentified. Epstein-Barr virus (EBV), vitamin D, and smoking are among the most well-established environmental risk factors in MS. Infectious mononucleosis, which is caused by delayed primary EBV infection, increases the risk of developing MS. EBV may also contribute to MS pathogenesis indirectly by activating silent human endogenous retrovirus-W. The emerging B-cell depleting therapies, particularly anti-CD20 agents such as rituximab, ocrelizumab, as well as the fully human ofatumumab, have shown promising clinical and magnetic resonance imaging benefit. One potential effect of these therapies is the depletion of memory B-cells, the primary reservoir site where EBV latency occurs. In addition, EBV potentially interacts with both genetic and other environmental factors to increase susceptibility and disease severity of MS. This review examines the role of EBV in MS pathophysiology and summarizes the recent clinical and radiological findings, with a focus on B-cells and in vivo imaging. Addressing the potential link between EBV and MS allows the better understanding of MS pathogenesis and helps to identify additional disease biomarkers that may be responsive to B-cell depleting intervention.

Application of advanced MRI techniques to monitor pharmacologic and rehabilitative treatment in multiple sclerosis: current status and future perspectives

Introduction: Advances in magnetic resonance imaging (MRI) technology and analyses are improving our understanding of the pathophysiology of multiple sclerosis (MS). Due to their ability to grade the presence of irreversible tissue loss, microstructural tissue abnormalities, metabolic changes and functional plasticity, the application of these techniques is also expanding our knowledge on the efficacy and mechanisms of action of different pharmacological and rehabilitative treatments. Areas covered: This review discusses recent findings derived from the application of advanced MRI techniques to evaluate the structural and functional substrates underlying the effects of pharmacologic and rehabilitative treatments in patients with MS. Current applications as outcome in clinical trials and observational studies, their interpretation and possible pitfalls in their use are discussed. Finally, how these techniques could evolve in the future to improve monitoring of disease progression and treatment response is examined. Expert commentary: The number of treatments currently available for MS is increasing. The application of advanced MRI techniques is providing reliable and specific measures to better understand the targets of different treatments, including neuroprotection, tissue repair, and brain plasticity. This is a fundamental progress to move toward personalized medicine and individual treatment selection.

Teriflunomide's Effect on Glia in Experimental Demyelinating Disease: A Neuroimaging and Histologic Study

BACKGROUND AND PURPOSE

Teriflunomide reduces disability progression and brain atrophy in multiple sclerosis patients. The exact mechanism of action by which teriflunomide exerts these effects is currently unknown. We assessed the effect of teriflunomide on brain glial cells in the Theiler's murine encephalomyelitis virus (TMEV) by using a histological approach in combination with neuroimaging.

METHODS

Forty-eight SJL female mice received an intracerebral injection of TMEV at 6-8 weeks of age and were then treated with teriflunomide (n = 24) or placebo (n = 24) for 9 months. They were examined with MRI and behavioral testing at 2, 6, and 9 months postinduction (mPI). Of those, 18 teriflunomide-treated and 17 controls mice were analyzed histologically at 9 mPI to sample from different brain regions for myelination status, microglial density, and oligodendroglial lineage. The histological and MRI outcomes were correlated.

RESULTS

Corpus callosum microglial density was numerically lower in the teriflunomide-treated mice compared to the control group (141.1 ± 21.7 SEM vs. 214.74 ± 34.79 SEM, Iba1⁺ cells/mm² , P = .087). Basal ganglia (BG) microglial density in the teriflunomide group exhibited a negative correlation with fractional anisotropy (P = .021) and a positive correlation with mean diffusivity (P = .034), indicating less inflammation and axonal damage. Oligodendroglial lineage cell and myelin density were not significantly different between treatment groups. However, a significant positive correlation between BG oligodendrocytes and BG volume (P = .027), and with N-acetyl aspartate concentration (P = .008), was found in the teriflunomide group, indicating less axonal loss.

CONCLUSION

Teriflunomide altered microglia density and oligodendrocytes differentiation, which was associated with less evident microstructural damage on MRI.