Racial differences in retinal neurodegeneration as a surrogate marker for cortical atrophy in multiple sclerosis

Volumetric and Asymmetric Index Analysis of Subcortical Structures in Multiple Sclerosis Patients: A Retrospective Study Using volBrain Software

Introduction Multiple sclerosis (MS) is a chronic and autoimmune disease that has a significant influence on the central nervous system, such as the brain and spinal cord, affecting millions of individuals globally. Understanding the connection between subcortical brain regions and MS is crucial for effective diagnostic and therapeutic approaches for treating this disabling disease. This study explores the relationship between volume and contours of asymmetry index of subcortical brain regions in individuals with MS using volBrain software (https://www.volbrain.net; developed by José V. Manjón (Valencia Polytechnic University, Valencia, Spain) and Pierrick Coupé (University of Bordeaux, Bordeaux, France)). Methods In our retrospective investigation, we admitted 100 Turkish individuals, comprising 50 patients diagnosed with relapsing-remitting MS (RRMS) (24 (48%) males and 26 (52%) females) and 50 healthy controls (23 (46%) males and 27 (54%) females), registered between October 2017 and February 2022 for five years and underwent assessment in the radiology department at the Teaching and Research Hospital of Kocaeli University; 1,150 Turkish patients were excluded from our study based on our exclusion criteria. We used magnetic resonance imaging with a 3-Tesla (3T) scanner and volBrain software to assess volumes (cm3) and asymmetry indexes due to asymmetry for different levels of atrophy of total intracranial, total brain, gray matter, white matter, and subcortical regions, the most affected regions in MS patients for both patient and control cohorts. Results Statistical analysis revealed a significant difference between patient and control groups (p < 0.001), with patient group mean age at 38.32 years and control group mean age at 32.88 years. Patient group exhibited lower values for total intracranial, total brain, gray matter, white matter, and cerebrospinal fluid volume compared to control group (p < 0.05). The results indicated a statistically significant decrease (p < 0.05) in the values for total intracranial and total brain volume, whereas all other values remained unchanged. We compared volumes of subcortical structures on the right and left sides and found that the putamen, thalamus, and globus pallidus had statistically lower values in the patient group than in the control group (p < 0.001), apart from the lateral ventricle. Furthermore, our retrospective investigation demonstrated a statistically significant difference in the globus pallidus asymmetry index, indicating a preference for the patient group (p < 0.05). A lower asymmetry index value signifies a larger volume for the right side of the subcortical regions of the brain when compared to the left side. Conclusion Brain atrophy, although characterized by irreversible tissue damage, is targeted by therapeutic interventions to prevent progression. It is, therefore, imperative to develop a universally accepted measurement standard for subcortical structures that also considers the inherent variability present within each structure. Our findings serve as an important basis and indicator for the determination of subcortical atrophy and asymmetry in MS, the prognosis of the disease, and the etiology of clinical symptoms. Subsequent research may benefit by adopting the novel approach of considering brain atrophy as an outcome rather than a predictor, thereby facilitating the elucidation of the intricate biological mechanisms that give rise to volume loss.

Choroid plexus volume as a marker of retinal atrophy in relapsing remitting multiple sclerosis

OBJECTIVE

To evaluate choroid plexus (CP) volume as a biomarker for predicting clinical disability and retinal layer atrophy in relapsing remitting multiple sclerosis (RRMS).

METHODS

Ninety-five RRMS patients and 26 healthy controls (HCs) underwent 3 T whole brain MRI, expanded disability status scale (EDSS) and optical coherence tomography (OCT). Fully automated intra-retinal segmentation was performed to obtain the volumes of the retinal nerve fiber layer (RNFL), combined ganglion cell layer -inner plexiform layer (GCIPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), retinal pigment epithelium (RPE), total macular volume (TMV) and papillomacular bundle (PMB). Automated segmentation of the CP within the lateral ventricles was performed and the choroid plexus volume (CPV) was normalized by total intracranial volume (TIV). Linear regression analysis and generalized estimating equation (GEE) models were applied to evaluate relationships between nCPV and EDSS, T2 lesion volume, disease duration, and retinal layer volumes, followed by Bonferroni correction analysis for multiple comparisons.

RESULTS

RRMS patients had larger tChPV compared to HCs (p < 0.001). After Bonferroni correction, there was a significant positive correlation between tChPV and EDSS (r2 = 0.25, p = 0.0002), disease duration (r2 = 0.30, p = 0.01), and T2 lesion volume (r2 = 0.39, p = 0.0000). A robust negative correlation was found between tChPV and RNFL (p < 0.001), GCIPL (p = 0.003), TMV (p = 0.0185), PMB (p < 0.0001), G (p = 0.04), T(p = 0.0001).

CONCLUSIONS

Our findings support the association of tChPV with disability and altered retinal integrity in RRMS.

Diversity, Equity, and Inclusion in the Multiple Sclerosis Community: A Call to Action

Many medical organizations have begun to confront the longstanding problem of inequalities in health care delivery and the undeniable effect of disparities on health outcomes. The Consortium of Multiple Sclerosis Centers (CMSC) recognizes that disparities affect the lives of many people with multiple sclerosis (MS) and acknowledges the need to address this as an organization. The CMSC recently (1) appointed a task force, (2) conducted a survey of its membership, (3) commissioned this review article and call to action, and (4) formulated a mission statement on diversity, equity, and inclusion (DEI), which was adopted by the CMSC's Board of Governors in March 2023. This paper summarizes recent literature on health care disparities in MS, particularly those relating to race/ethnicity, sexual orientation, and gender identity. It presents findings from CMSC's survey of members' awareness of DEI issues, the need for education and resources for MS care providers, and existing institutional policies on DEI in the members' practice settings. It also presents the task force's recommendations for next steps, which includes the goal of greater diversity in the MS workforce of the future. The CMSC will continue to revisit DEI policies and practices over time with the goal of motivating greater awareness, momentum, and positive changes within the MS community.

Optical Coherence Tomography in Chronic Relapsing Inflammatory Optic Neuropathy, Neuromyelitis Optica and Multiple Sclerosis: A Comparative Study

Purpose: To examine the optical coherence tomography (OCT) features of the retina in patients with chronic relapsing inflammatory optic neuropathy (CRION) and compare them with those of neuromyelitis optica spectrum disorder (NMOSD), relapsing-remitting multiple sclerosis (RRMS) with and without optic neuritis (ON), and healthy controls (HC). Methods: In this retrospective cross-sectional study, we used spectral domain OCT to evaluate the retinal structure of 14 participants with CRION, 22 with NMOSD, 40 with RRMS with unilateral ON, and 20 HC. The peripapillary retinal nerve fiber layer (pRNFL), total macular volume (TMV), and papillomacular bundle (PMB) were measured, and intra-retinal segmentation was performed to obtain the retinal nerve fiber (RNFL), ganglion cell (GCL), inner plexiform (IPL), inner nuclear (INL), outer plexiform (OPL) and outer nuclear (ONL) layer volumes. Results: The global pRNFL [39.33(±1.8) µm] and all its quadrants are significantly thinner in CRION compared with all other groups (p < 0.05). CRION patients have decreased volumes of TMV, RNFL, GCL, and IPL compared with all other groups (p < 0.05). Conclusion: Severe thinning in pRNFL and thinning in intra-retinal segments of IPL, GCL, RNFL, and TMV could be helpful in differentiating CRION from NMOSD and RRMS.

Advancing Care and Outcomes for African American Patients With Multiple Sclerosis

Multiple sclerosis (MS) has historically been underdiagnosed and undertreated among African Americans. Recent evidence suggests that African Americans with MS have a different clinical presentation, increased disease incidence and burden, and worse long-term outcomes vs their White counterparts. Due to limited data available for African Americans in MS clinical trials, it is difficult to make informed, generalizable conclusions about the natural history, prognosis, and therapeutic response in this population. In this narrative review, we highlight the nature and magnitude of the health disparities experienced by African Americans with MS and underscore the pressing need to increase knowledge about and understanding of MS disease manifestations in this group. In addition, we describe the mission and objectives of the recently established National African Americans with Multiple Sclerosis Registry, which is intended to be a platform to advance the care of African Americans with MS and address health disparities they may experience.

Retinal nerve fiber and ganglion cell complex layer thicknesses mirror brain atrophy in patients with relapsing-remitting multiple sclerosis

BACKGROUND

Multiple sclerosis (MS) is associated with progressive brain atrophy, which in turn correlates with disability, depression, and cognitive impairment. Relapsing-remitting multiple sclerosis (RRMS) is a type of MS in which relapses of the disease are followed by remission periods. This is the most common type of the disease. There is a significant need for easy and low-cost methods to these cerebral changes. Changes in retinal layer thickness may reflect alterations in brain white and gray matter volumes. Therefore, this paper aims to determine whether retinal layer thickness, measured using optical coherence tomography (OCT), correlates with volumetric brain assessments obtained by magnetic resonance imaging (MRI).

METHODS

This retrospective cohort study recruited 53 patients with relapsing-remitting MS who underwent MRI and OCT examinations for evaluation of brain compartment volumes and thickness of retinal layers, respectively. OCT parameters, including central retinal thickness; retinal nerve fiber layer thickness (RNFL, peripapillary thickness); ganglion cell complex thickness (GCC, macular thickness); and Expanded Disability Status Scale (EDSS) results were compared with MRI parameters (cerebral cortex; cerebral cortex and basal ganglia combined; brain hemispheres without the ventricular system; and white matter plaques). We also checked whether there is a correlation between the number of RRMS and OCT parameters.

OBJECTIVE

Our primary objective was to identify whether these patients had retinal thickness changes, and our secondary objective was to check if those changes correlated with the MRI brain anatomical changes.

RESULTS

RNFL and GCC thicknesses were strongly (p-value <  0.05) associated with (i) cerebral cortex volume, (ii) combination of brain cortex and basal ganglia volumes, and (iii) the hemispheres but without the ventricular system. White matter plaques (combined) showed only weak or no correlation with RNFL and GCC. There was no correlation between central retinal thickness and brain compartment volumes, and there were weak or no correlations between the summary EDSS scores and OCT results.

CONCLUSIONS

Retinal layer thickness measured by OCT correlates with select volumetric brain assessments on MRI. During the course of RRMS, the anatomo-pathological structure of the retina might serve as a surrogate marker of brain atrophy and clinical progression within selected domains.

Effect of Obesity on Retinal Integrity in African Americans and Caucasian Americans With Relapsing Multiple Sclerosis

Objective: To study the effect of obesity on retinal structures in African Americans (AAs) and Caucasian Americans (CAs) with relapsing-remitting multiple sclerosis (RRMS).

Methodology: About 136 patients with RRMS without history of optic neuritis were divided into two groups, based on body mass index (BMI): 67 obese (40 AA, 27 CA, mean BMI ± SD: 36.7 ± 5.8), and 69 non-obese (23 AA, 46 CA, mean BMI ± SD: 24.0 ± 3.1). The peripapillary retinal nerve fiber layer (pRNFL) thickness was quantified by optical coherence tomography (OCT) and was segmented into quadrant thickness: superior (S), inferior (I), temporal (T), and nasal (N). Papillomacular bundle (PMB) thickness, retinal nerve fiber layer (RNFL), ganglion cell + inner plexiform layer (GCIPL), inner nuclear (INL), outer plexiform (OPL), outer nuclear (ONL), and total macular (TMV) volumes were obtained.

Results: Obesity was associated with lower T thickness (58.54 ± 15.2 vs. 61.9 12.4, p = 0.044), higher INL (0.98 ± 0.07 vs. 0.96 ± 0.06, p = 0.034), and lower RNFL (0.77 ± 0.14 vs. 0.82 ± 0.12, p = 0.009) volumes. Obese AA had significantly thinner T (58.54 ± 15.19 vs. 61.91 ± 12.39, p = 0.033), N (68.94 ± 2.7 vs. 77.94 ± 3.3, p = 0.044), and TMV (8.15 ± 0.07 vs. 8.52 ± 0.09, p = 0.003), RNFL (0.74 ± 0.02 vs. 0.82 ± 0.02, p = 0.013), OPL (0.76 ± 0.01 vs. 0.79 ± 0.1, p = 0.050), ONL (1.68 ± 0.031 vs. 1.79 ± 0.038, p = 0.026), and GCIPL (1.78 ± 0.04 vs. 1.9 ± 0.05, p = 0.038) compared to obese CA. Among patients with non-obesity, the ONL was significantly lower in AA (1.78 ± 0.04 vs. 1.9 ± 0.05, p < 0.001).

Conclusions: Obesity is associated with retinal structure abnormalities in patients with RRMS. Its impact might be more prominent in AA than CA. Large longitudinal studies are needed to validate our findings.

Cortical surface thickness, subcortical volumes and disability between races in relapsing-remitting multiple sclerosis

BACKGROUND

The interplay between cortical surface thickness (CTh), subcortical volumes (SCV) and disability in patients with relapsing remitting multiple sclerosis (RRMS) is still not clear.

OBJECTIVE

To examine the relationship between CTh, SCV, and disability and investigate differences in CTh, SCV and disability between African Americans (AA) and Caucasian Americans (CA).

METHODS

Sixty-five RRMS (33AA, 32 CA) participants underwent Expanded Disability Status Scale and Multiple Sclerosis Functional Composite (MSFC) assessments, including timed 25-foot walk (T25FW), nine-hole peg test (9HPT) on dominant (D) and non-dominant hand (ND) and paced auditory serial addition test (PASAT-3). Symbol digit modalities test (SDMT) was also administered. All participants underwent 3T brain MRI. CTh was measured in the Frontal (FA), Parietal (PA), Temporal (TA), Occipital (OA), Cingulate (CA), and Global (GA) cortical surface areas (CSA). SCV measurements included Thalamus (TV), Caudate (CV), Putamen (PV), Pallidum (PaV), Hippocampus (HV), Amygdala (AV), Accumbens (AcV), Brain Stem (BSV), and Deep Gray Matter Total Volume (DGMTV). A general linear model with multivariate analysis (MANOVA) was used to determine the differences between the two cohorts (SPSS vs 25). Spearman rank correlation analysis was performed to investigate the relationship between CTh and MSFC.

RESULTS

AA have significantly decreased FA, PA, TA, GA CTh compared to CA (p = 0.004, p = 0.018, p = 0.013, p = 0.015, respectively). SCV measurements were not significantly different. Only in CA, the MSFC measures correlate significantly with regional CSA CTh. In both races and in the entire group, T25FW correlates with TV, PV, AV, AcV and DGMTV (p < 0.05). Only in AA and the entire cohort, PASAT-3 correlates with TV and AcV(p = 0.041, p = 0.006, p = 0.006, p = 0.000 respectively).

CONCLUSIONS

Differences in CSA CTh reinforce the different disease pathobiology between AA and CA. Regional CTh may represent a useful biomarker related to multi-domain disability only in CA, while in AA DGM injury might be a more important contributor to disability. Longitudinal, large-scale studies are warranted to confirm our findings.

Clinical Characteristics of Multiple Sclerosis in African-Americans

PURPOSE OF REVIEW

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system that affects nearly 1 million people in the USA and has the potential to profoundly affect physical ability and income potential at a young age. Since a landmark paper was published in 2014, few studies have looked at differences in MS disease characteristics between African-American and Caucasian patients.

RECENT FINDINGS

African-American patients often have a more severe MS disease course, as well as biomarker data which can portend a worse prognosis. While the sample sizes are usually quite small, subgroup analyses of African-American patients have been performed to evaluate efficacy of disease-modifying treatments as compared with the entire study population, made up of primarily Caucasians. In an era where we strive for personalized medicine, understanding racial differences in MS may help us better treat African-American patients in the future.

Optical coherence tomography and multiple sclerosis: Update on clinical application and role in clinical trials

Optical coherence tomography (OCT) has emerged as a fast, non-invasive, inexpensive, high-resolution imaging technique in multiple sclerosis (MS). Retinal layer quantification by OCT facilitates a 'window' into not only local retinal pathology but also global neurodegenerative processes, recognised to be the principal substrates of disability accumulation in MS. While OCT measures in MS have been demonstrated to reflect visual function, inflammatory activity outside of the visual pathways, disability measures including the prediction of disability progression, whole brain atrophy, and the differential neuroprotective effects of disease-modifying therapies, debate continues regarding the clinical utility of OCT in everyday practice. This review presents an overview of the evidence supporting OCT, with particular focus on its application in the MS clinic. We will also discuss the role of OCT in MS clinical trials to develop novel neuroprotective and potential remyelinating therapies.