Pavan Bhargava

Optical Coherence Tomography Reflects Brain Atrophy in Multiple Sclerosis: A Four-Year Study

The aim of this work was to determine whether atrophy of specific retinal layers and brain substructures are associated over time, in order to further validate the utility of optical coherence tomography (OCT) as an indicator of neuronal tissue damage in patients with multiple sclerosis (MS).

Safety and immunologic effects of high- vs low-dose cholecalciferol in multiple sclerosis

Objective: To study the safety profile and characterize the immunologic effects of high- vs low-dose cholecalciferol supplementation in patients with multiple sclerosis (MS). Methods: In this double-blind, single-center randomized pilot study, 40 patients with relapsing-remitting MS were randomized to receive 10,400 IU or 800 IU cholecalciferol daily for 6 months. Assessments were performed at baseline and 3 and 6 months. Results: Mean increase of 25-hydroxyvitamin D levels from baseline to final visit was larger in the high-dose group (34.9 ng/mL; 95% confidence interval [CI] 25.0–44.7 ng/mL) than in the low-dose group (6.9 ng/mL; 95% CI 1.0–13.7 ng/mL). Adverse events were minor and did not differ between the 2 groups. Two relapses occurred, one in each treatment arm. In the high-dose group, we found a reduction in the proportion of interleukin-17+CD4+ T cells (p = 0.016), CD161+CD4+ T cells (p = 0.03), and effector memory CD4+ T cells (p = 0.021) with a concomitant increase in the proportion of central memory CD4+ T cells (p = 0.018) and naive CD4+ T cells (p = 0.04). These effects were not observed in the low-dose group. Conclusions: Cholecalciferol supplementation with 10,400 IU daily is safe and tolerable in patients with MS and exhibits in vivo pleiotropic immunomodulatory effects in MS, which include reduction of interleukin-17 production by CD4+ T cells and decreased proportion of effector memory CD4+ T cells with concomitant increase in central memory CD4+ T cells and naive CD4+ T cells. Classification of evidence: This study provides Class I evidence that cholecalciferol supplementation with 10,400 IU daily is safe and well-tolerated in patients with MS and exhibits in vivo pleiotropic immunomodulatory effects.

Gut Microbiome and Multiple Sclerosis

The commensal flora that lives in the human gut is a unique ecosystem that has evolved over millennia with human beings. The importance of the microbiota in various bodily functions is gradually becoming more apparent. Besides the gut microbiome playing a role in bowel-related disorders, a role in metabolic and autoimmune disorders is becoming clearer. The gut bacteria play a role in educating the immune system and hence may be a player in the development of multiple sclerosis. We examine the different sources of information linking the gut microbiota to multiple sclerosis and examine the future avenues for utilizing the knowledge of the gut microbiome to potentially treat and prevent multiple sclerosis.

The Vitamin D to Ameliorate Multiple Sclerosis (VIDAMS) trial: Study design for a multicenter, randomized, double-blind controlled trial of vitamin D in multiple sclerosis

BACKGROUND Lower levels of vitamin D are associated with increased MS risk and with greater clinical and brain MRI activity in established relapsing MS. OBJECTIVE The VIDAMS trial (NCT01490502) is evaluating whether high-dose vitamin D supplementation reduces the risk of MS activity. DESIGN/METHODS Eligibility criteria include diagnosis of RRMS, age 18 to 50 years, and Expanded Disability Status Scale ≤4.0. Disease duration and activity requirements depend on whether 2005 or 2010 criteria are used for diagnosis. Enrollment is restricted based on prior MS therapy exposure and recent vitamin D use. After completing a one-month run-in of glatiramer acetate, 172 patients will be randomized 1:1 to oral vitamin D(3) 5000 IU versus 600 IU daily. Clinical visits occur every 12 weeks for 96 weeks. RESULTS Sixteen sites throughout the United States are participating in the trial. Complete enrollment is expected by late 2014, with follow-up through 2016. No interim analyses are planned. The primary outcome for the trial is the proportion of patients experiencing a relapse in each group. Other clinical, patient-reported, and MRI outcomes will be evaluated. CONCLUSIONS The VIDAMS trial will provide critical information about the safety and efficacy of vitamin D therapy in RRMS, with implications for MS patients worldwide.

Cerebrospinal fluid ceramides from patients with multiple sclerosis impair neuronal bioenergetics

Axonal damage is a prominent cause of disability and yet its pathogenesis is incompletely understood. Using a xenogeneic system, here we define the bioenergetic changes induced in rat neurons by exposure to cerebrospinal fluid samples from patients with multiple sclerosis compared to control subjects. A first discovery cohort of cerebrospinal fluid from 13 patients with multiple sclerosis and 10 control subjects showed that acute exposure to cerebrospinal fluid from patients with multiple sclerosis induced oxidative stress and decreased expression of neuroprotective genes, while increasing expression of genes involved in lipid signalling and in the response to oxidative stress. Protracted exposure of neurons to stress led to neurotoxicity and bioenergetics failure after cerebrospinal fluid exposure and positively correlated with the levels of neurofilament light chain. These findings were validated using a second independent cohort of cerebrospinal fluid samples (eight patients with multiple sclerosis and eight control subjects), collected at a different centre. The toxic effect of cerebrospinal fluid on neurons was not attributable to differences in IgG content, glucose, lactate or glutamate levels or differences in cytokine levels. A lipidomic profiling approach led to the identification of increased levels of ceramide C16:0 and C24:0 in the cerebrospinal fluid from patients with multiple sclerosis. Exposure of cultured neurons to micelles composed of these ceramide species was sufficient to recapitulate the bioenergetic dysfunction and oxidative damage induced by exposure to cerebrospinal fluid from patients with multiple sclerosis. Therefore, our data suggest that C16:0 and C24:0 ceramides are enriched in the cerebrospinal fluid of patients with multiple sclerosis and are sufficient to induce neuronal mitochondrial dysfunction and axonal damage.

Automatic segmentation of microcystic macular edema in OCT

Microcystic macular edema (MME) manifests as small, hyporeflective cystic areas within the retina. For reasons that are still largely unknown, a small proportion of patients with multiple sclerosis (MS) develop MME-predominantly in the inner nuclear layer. These cystoid spaces, denoted pseudocysts, can be imaged using optical coherence tomography (OCT) where they appear as small, discrete, low intensity areas with high contrast to the surrounding tissue. The ability to automatically segment these pseudocysts would enable a more detailed study of MME than has been previously possible. Although larger pseudocysts often appear quite clearly in the OCT images, the multi-frame averaging performed by the Spectralis scanner adds a significant amount of variability to the appearance of smaller pseudocysts. Thus, simple segmentation methods only incorporating intensity information do not perform well. In this work, we propose to use a random forest classifier to classify the MME pixels. An assortment of both intensity and spatial features are used to aid the classification. Using a cross-validation evaluation strategy with manual delineation as ground truth, our method is able to correctly identify 79% of pseudocysts with a precision of 85%. Finally, we constructed a classifier from the output of our algorithm to distinguish clinically identified MME from non-MME subjects yielding an accuracy of 92%.

Outer retinal changes following acute optic neuritis

Background: Retinal nerve fiber and ganglion cell+inner plexiform (GCIP) layer thinning following multiple sclerosis-related acute optic neuritis (AON) is well described. However, whether AON results in changes in the inner nuclear (INL), outer plexiform (OPL), outer nuclear (ONL) and/or photoreceptor segment (PS) layers remains undetermined. Objectives: The objective of this paper is to determine if INL+OPL and/or ONL+PS changes occur following AON. Methods: Thirty-three AON patients underwent serial optical coherence tomography (OCT) and visual function testing (mean follow-up: 25 months). Longitudinal changes in retinal layer thickness were analyzed using mixed-effects linear regression. Results: Four months following AON, the mean decrease in GCIP thickness relative to baseline was 11.4% (p < 0.001). At four months, a concomitant 3.4% increase in average ONL+PS thickness was observed (p < 0.001). The percentage decrease in GCIP thickness and increase in ONL+PS thickness were strongly correlated (r = −0.70; p < 0.001). Between months 4 to 12, ONL+PS thickness declined and, at 12 months, was no longer significantly different from baseline (mean change: 0.5%; p = 0.37). Similar, albeit less robust, changes in the INL+OPL were observed. Conclusions: Following AON, dynamic changes occur in the deep retinal layers, which are proportional to GCIP thinning. These novel findings help further our understanding of the biological and/or anatomical sequelae resulting from AON.

Multiple sclerosis patients have a diminished serologic response to vitamin D supplementation compared to healthy controls

Background: Vitamin D insufficiency is a risk factor for multiple sclerosis (MS), and patients do not always show the expected response to vitamin D supplementation. Objective: We aimed to determine if vitamin D supplementation leads to a similar increase in serum 25-hydroxyvitamin-D (25(OH)D) levels in patients with MS and healthy controls (HCs). Methods: Participants in this open-label study were female, white, aged 18–60 years, had 25(OH)D levels ⩽ 75 nmol/l at screening, and had relapsing–remitting MS (RRMS) or were HCs. Participants received 5000 IU/day of vitamin D3 for 90 days. Utilizing generalized estimating equations we examined the relationship between the primary outcome (serum 25(OH)D level) and the primary (MS versus HC status) and secondary predictors. Results: For this study 27 MS patients and 30 HCs were enrolled. There was no significant difference in baseline 25(OH)D level or demographics except for higher body mass index (BMI) in the MS group (25.3 vs. 23.6 kg/m2, p=0.035). In total, 24 MS subjects and 29 HCs completed the study. In a multivariate model accounting for BMI, medication adherence, and oral contraceptive use, MS patients had a 16.7 nmol/l (95%CI: 4.2, 29.2, p=0.008) lower increase in 25(OH)D levels compared with HCs. Conclusions: Patients with MS had a lower increase in 25(OH)D levels with supplementation, even after accounting for putative confounders.

Disease-modifying therapies modulate retinal atrophy in multiple sclerosis A retrospective study

Objective: To retrospectively investigate whether disease-modifying therapies (DMTs) exert differential effects on rates of retinal atrophy in relapsing-remitting multiple sclerosis (RRMS), as assessed using optical coherence tomography (OCT). Methods: A total of 402 patients with RRMS followed at the Johns Hopkins MS Center who underwent Cirrus-HD OCT were assessed for eligibility. Inclusion criteria included at least 1 year of OCT follow-up and adherence to a single DMT during the period of follow-up. Combined thickness of the ganglion cell + inner plexiform (GCIP) and other retinal layers was computed utilizing automated macular segmentation. Retinal thickness changes were analyzed using mixed-effects linear regression. Results: The effects of glatiramer acetate (GA; n = 48), natalizumab (NAT; n = 46), and interferon-β-1a subcutaneously (IFNSC; n = 35) and intramuscularly (IFNIM; n = 28) were assessed. Baseline analyses revealed no significant differences between groups in terms of age, sex, optic neuritis history, or follow-up duration. During follow-up, relative to NAT-treated patients, IFNSC- and GA-treated patients exhibited 0.37 μm/y (p < 0.001) and 0.14 μm/y (p = 0.035) faster rates of GCIP thinning, respectively, adjusting for the interval between initiation of DMT and OCT monitoring (gap time), age, sex, relapses, and disease duration. In the IFNSC group, GCIP thinning was 1.53 μm/y faster during the first year of therapy vs during the time interval afterwards (p < 0.001). Conclusions: Rates of GCIP atrophy in patients with RRMS vary according to DMT utilization. Our findings support OCT for monitoring neurodegenerative treatment effects in the retina, an easily accessible tissue, and as a practical outcome measure in RRMS clinical trials.

Dimethyl fumarate targets GAPDH and aerobic glycolysis to modulate immunity

Immunometabolism as therapeutic target Dimethyl fumarate (DMF) is an immunomodulatory compound used to treat multiple sclerosis and psoriasis whose mechanisms of action remain only partially understood. Kornberg et al. found that DMF and its metabolite, monomethyl fumarate, succinate the glycolytic enzyme GAPDH (see the Perspective by Matsushita and Pearce). After DMF treatment, GAPDH was inactivated, and aerobic glycolysis was down-regulated in both myeloid and lymphoid cells. This resulted in down-modulated immune responses because inflammatory immune-cell subsets require aerobic glycolysis. Thus, metabolism can serve as a viable therapeutic target in autoimmune disease. Science, this issue p. 449; see also p. 377 An immunomodulatory drug suppresses immune responses by modulating metabolism in activated immune cells. Activated immune cells undergo a metabolic switch to aerobic glycolysis akin to the Warburg effect, thereby presenting a potential therapeutic target in autoimmune disease. Dimethyl fumarate (DMF), a derivative of the Krebs cycle intermediate fumarate, is an immunomodulatory drug used to treat multiple sclerosis and psoriasis. Although its therapeutic mechanism remains uncertain, DMF covalently modifies cysteine residues in a process termed succination. We found that DMF succinates and inactivates the catalytic cysteine of the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in mice and humans, both in vitro and in vivo. It thereby down-regulates aerobic glycolysis in activated myeloid and lymphoid cells, which mediates its anti-inflammatory effects. Our results provide mechanistic insight into immune modulation by DMF and represent a proof of concept that aerobic glycolysis is a therapeutic target in autoimmunity.