Effect of high-dose simvastatin on brain atrophy and disability in secondary progressive multiple sclerosis (MS-STAT): a randomised, placebo-controlled, phase 2 trial

Pharmacological Approaches to Delaying Disability Progression in Patients with Multiple Sclerosis

In individuals with multiple sclerosis, physical and cognitive disability progression are clinical and pathophysiological hallmarks of the disease. Despite shortcomings, particularly in capturing cognitive deficits, the Expanded Disability Status Scale is the assessment of disability progression most widely used in clinical trials. Here, we review treatment effects on disability that have been reported in large clinical trials of disease-modifying treatment, both among patients with relapsing-remitting disease and among those with progressive disease. However, direct comparisons are confounded to some degree by the lack of consistency in assessment of disability progression across trials. Confirmed disability progression (CDP) is a more robust measure when performed over a 6-month than a 3-month interval, and reduction in the risk of 6-month CDP in phase III trials provides good evidence for the beneficial effects on disability of several high-efficacy treatments for relapsing-remitting disease. It is also becoming increasingly clear that therapies effective in relapsing-remitting disease have little impact on the course of progressive disease. Given that the pathophysiological mechanisms, which lead to the long-term accrual of physical and cognitive deficits, are evident at the earliest stages of disease, it remains a matter of debate whether the most effective therapies are administered early enough to afford patients the best long-term outcomes.

Secondary Progression in Multiple Sclerosis: Neuronal Exhaustion or Distinct Pathology?

Prevention of progression in neurological diseases, particularly in multiple sclerosis (MS) but also in neurodegenerative diseases, remains a significant challenge. MS patients switch from a relapsing-remitting to a progressive disease course, but it is not understood why and how this conversion occurs and why some patients never experience disease progression. Do aging and accumulation of neuronal damage induce progression, or do cognitive symptoms and accelerated grey matter (GM) atrophy point to distinct processes affecting networks? This review weighs accepted dogma against real data on the secondary progressive phase of the disease, highlighting current challenges in this important field and directions towards development of treatment strategies to slow or prevent progression of disability.

Pushing Forward: Remyelination as the New Frontier in CNS Diseases

The evolutionary acquisition of myelin sheaths around large caliber axons in the central nervous system (CNS) represented a milestone in the development of vertebrate higher brain function. Myelin ensheathment of axons enabled saltatory conduction and thus accelerated information processing. However, a number of CNS diseases harm or destroy myelin and oligodendrocytes (myelin-producing cells), ultimately resulting in demyelination. In the adult CNS, new oligodendrocytes can be generated from a quiescent pool of precursor cells, which - upon differentiation - can replace lost myelin sheaths. The efficiency of this spontaneous regeneration is limited, which leads to incomplete remyelination and residual clinical symptoms. Here, we discuss CNS pathologies characterized by white matter degeneration and regeneration and highlight drugs that could potentially serve as remyelination therapies.

Obesity and brain inflammation: a focus on multiple sclerosis

The increase in prevalence of obesity in industrialized societies is an indisputable fact. However, the apparent passive role played by adipocytes, in pathophysiological terms, has been gradually substituted by a metabolically active performance, relevant to many biochemical mechanisms that may contribute to a chronic low-grade inflammatory status, which increasingly imposes itself as a key feature of obesity. This chronic inflammatory status will have to be integrated into the complex equation of many diseases in which inflammation plays a crucial role. Multiple sclerosis (MS) is a chronic inflammatory condition typically confined to the central nervous system, and many work has been produced to find possible points of contact between the biology of this immune-mediated disease and obesity. So far, clinical data are not conclusive, but many biochemical features have been recently disclosed. Brain inflammation has been implicated in some of the mechanisms that lead to obesity, which has also been recognized as an important player in inducing some degree of immune dysfunction. In this review, we collected evidence that allows establishing bridges between obesity and MS. After considering epidemiological controversies, we will focus on possible shared mechanisms, as well as on the potential contributions that disease-modifying drugs may have on this apparent relationship of mutual interference.

A randomized placebo-controlled lovastatin trial for neurobehavioral function in neurofibromatosis I

Objective

Lovastatin has been shown to reverse learning deficits in a mouse model of Neurofibromatosis Type 1 (NF1), a common monogenic disorder caused by a mutation in the Ras‐MAPK pathway and associated with learning disabilities. We conducted a randomized double‐blind placebo‐controlled trial to assess lovastatin's effects on cognition and behavior in patients with NF1.

Method

Forty‐four NF1 patients (mean age 25.7+/−11.6 years; 64% female) were randomly assigned to 14 weeks of lovastatin (N = 23; maximum dose of 80 mg/day for adult participants and 40 mg/day for children) or placebo (N = 21). Based on findings in the mouse model, primary outcome measures were nonverbal learning and working memory. Secondary outcome measures included verbal memory, attention, and self/parent‐reported behavioral problems, as well as tolerability of medication. Participants also underwent neuroimaging assessments at baseline and 14 weeks, to determine whether neural biomarkers were associated with treatment response. Linear mixed models assessed for differential treatment effects on outcome measures.

Results

Twelve participants dropped from the study prior to completion (8 placebo, 4 lovastatin), resulting in 32 completers (15 placebo, 17 lovastatin). Lovastatin was well‐tolerated, with no serious adverse events. Differential improvement favoring lovastatin treatment was observed for one primary (working memory; effect size f² = 0.70, P < 0.01) and two secondary outcome measures (verbal memory, f² = 0.19, P = 0.02, and adult self‐reported internalizing problems, f² = 0.26, P = 0.03). Exploratory moderator analyses revealed that higher baseline neural activity in frontal regions was associated with larger treatment effects.

Interpretation

These preliminary results suggest beneficial effects of lovastatin on some learning and memory functions, as well as internalizing symptoms in patients with NF1.

Cardiovascular risk factors are associated with increased lesion burden and brain atrophy in multiple sclerosis

BACKGROUND

Cardiovascular (CV) risk factors have been associated with changes in clinical outcomes in patients with multiple sclerosis (MS).

OBJECTIVES

To investigate the frequency of CV risks in patients with MS and their association with MRI outcomes.

METHODS

In a prospective study, 326 patients with relapsing-remitting MS and 163 patients with progressive MS, 61 patients with clinically isolated syndrome (CIS) and 175 healthy controls (HCs) were screened for CV risks and scanned on a 3T MRI scanner. Examined CV risks included hypertension, heart disease, smoking, overweight/obesity and type 1 diabetes. MRI measures assessed lesion volumes (LVs) and brain atrophy. Association between individual or multiple CV risks and MRI outcomes was examined adjusting for age, sex, race, disease duration and treatment status.

RESULTS

Patients with MS showed increased frequency of smoking (51.7% vs 36.5%, p = 0.001) and hypertension (33.9% vs 24.7%, p=0.035) compared with HCs. In total, 49.9% of patients with MS and 36% of HCs showed ≥ 2 CV risks (p = 0.003), while the frequency of ≥ 3 CV risks was 18.8% in the MS group and 8.6% in the HCs group (p = 0.002). In patients with MS, hypertension and heart disease were associated with decreased grey matter (GM) and cortical volumes (p < 0.05), while overweight/obesity was associated with increased T1-LV (p < 0.39) and smoking with decreased whole brain volume (p = 0.049). Increased lateral ventricle volume was associated with heart disease (p = 0.029) in CIS.

CONCLUSIONS

Patients with MS with one or more CV risks showed increased lesion burden and more advanced brain atrophy.

The role of MRI in the evaluation of secondary progressive multiple sclerosis

Magnetic resonance imaging already has an established role in the diagnosis of multiple sclerosis, but it also has the potential to provide prognostic information, and to monitor [corrected] disease progression in clinical trials and practice. Magnetic resonance imaging measures are increasingly being used as the primary outcome in early phase clinical trials of immunomodulatory therapies (for example brain white matter lesion counts or volumes, and gadolinium contrast enhancing lesions) and putatively neuroprotective agents (for example measures of whole brain atrophy), and trials of agents that promote remyelination are also likely to follow suit. In this review we consider the use of magnetic resonance imaging measures as predictors and markers of disease progression in multiple sclerosis, and explore possible future directions in this rapidly developing field.

Progressive multiple sclerosis

PURPOSE OF REVIEW

The purpose of this study is to highlight the pathological features and clinical aspects of progressive multiple sclerosis (PMS) and also the results of clinical trial experience to date and review ongoing clinical trials and prospective new treatment options. This study will explain the challenges of clinical trial design in PMS.

RECENT FINDINGS

Multiple sclerosis (MS) has been identified as a chronic immune mediated disease, and the progressive phase of the disease appears to have significant neurodegenerative mechanisms. The classification of the course of PMS has been reorganized into categories of active vs. inactive inflammatory disease and the presence vs. absence of gradual disease progression. This differentiation allows clearer conceptualization of PMS and possibly even more efficient recruitment of PMS patients into clinical trials. Clinical trial experience to date in PMS has been negative with anti-inflammatory medications used in relapsing MS. Simvastatin was recently tested in a phase II trial and showed a 43% reduction of annualized atrophy progression in secondary progressive MS. Ongoing PMS trials are currently being conducted with the phosphodiesterase inhibitor ibudilast, S1P modulator siponimod and anti-B-cell therapy ocrelizumab. Several efforts for development of outcome measures in PMS are ongoing.

SUMMARY

PMS represents a significant challenge, as the pathogenesis of the disease is not well understood, no validated outcome metrics have been established and clinical trial experience to date has been disappointing. Advances in the understanding of the disease and lessons learned in previous clinical trials are paving the way for successful development of disease-modifying agents for this disease.

The Cellular and Molecular Basis of Translational Immunometabolism

The immune response requires major changes to metabolic processes, and indeed, energy metabolism and functional activation are fully integrated in immune cells to determine their ability to divide, differentiate, and carry out effector functions. Immune cell metabolism has therefore become an attractive target area for therapeutic purposes. A neglected aspect in the translation of immunometabolism is the critical connection between systemic and cellular metabolism. Here, we discuss the importance of understanding and manipulating the integration of systemic and immune cell metabolism through in-depth analysis of immune cell phenotype and function in human metabolic diseases and, in parallel, of the effects of conventional metabolic drugs on immune cell differentiation and function. We examine how the recent identification of selective metabolic programs operating in distinct immune cell subsets and functions has the potential to deliver tools for cell- and function-specific immunometabolic targeting.

Therapeutic Advances and Future Prospects in Progressive Forms of Multiple Sclerosis

Identifying effective therapies for the treatment of progressive forms of multiple sclerosis (MS) is a highly relevant priority and one of the greatest challenges for the global MS community. Better understanding of the mechanisms involved in progression of the disease, novel trial designs, drug repurposing strategies, and new models of collaboration may assist in identifying effective therapies. In this review, we discuss various therapies under study in phase II or III trials, including antioxidants (idebenone); tyrosine kinase inhibitors (masitinib); sphingosine receptor modulators (siponimod); monoclonal antibodies (anti-leucine-rich repeat and immunoglobulin-like domain containing neurite outgrowth inhibitor receptor-interacting protein-1, natalizumab, ocrelizumab, intrathecal rituximab); hematopoetic stem cell therapy; statins and other possible neuroprotective agents (amiloride, riluzole, fluoxetine, oxcarbazepine); lithium; phosphodiesterase inhibitors (ibudilast); hormone-based therapies (adrenocorticotrophic hormone and erythropoietin); T-cell receptor peptide vaccine (NeuroVax); autologous T-cell immunotherapy (Tcelna); MIS416 (a microparticulate immune response modifier); dopamine antagonists (domperidone); and nutritional supplements, including lipoic acid, biotin, and sunphenon epigallocatechin-3-gallate (green tea extract). Given ongoing and planned clinical trial initiatives, and the largest ever focus of the global research community on progressive MS, future prospects for developing targeted therapeutics aimed at reducing disability in progressive forms of MS appear promising.

Importance of Apolipoprotein A-I in Multiple Sclerosis

Jean-Martin Charcot has first described multiple sclerosis (MS) as a disease of the central nervous system (CNS) over a century ago. MS remains incurable today, and treatment options are limited to disease modifying drugs. Over the years, significant advances in understanding disease pathology have been made in autoimmune and neurodegenerative components. Despite the fact that brain is the most lipid rich organ in human body, the importance of lipid metabolism has not been extensively studied in this disorder. In MS, the CNS is under attack by a person's own immune system. Autoantigens and autoantibodies are known to cause devastation of myelin through up regulation of T-cells and cytokines, which penetrate through the blood-brain barrier to cause inflammation and myelin destruction. The anti-inflammatory role of high-density lipoproteins (HDLs) has been implicated in a plethora of biological processes: vasodilation, immunity to infection, oxidation, inflammation, and apoptosis. However, it is not known what role HDL plays in neurological function and myelin repair in MS. Understanding of lipid metabolism in the CNS and in the periphery might unveil new therapeutic targets and explain the partial success of some existing MS therapies.

Innate and adaptive immune responses in the CNS

Almost every disorder of the CNS is said to have an inflammatory component, but the precise nature of inflammation in the CNS is often imprecisely defined, and the role of CNS-resident cells is uncertain compared with that of cells that invade the tissue from the systemic immune compartment. To understand inflammation in the CNS, the term must be better defined, and the response of tissue to disturbances in homoeostasis (eg, neurodegenerative processes) should be distinguished from disorders in which aberrant immune responses lead to CNS dysfunction and tissue destruction (eg, autoimmunity). Whether the inflammatory tissue response to injury is reparative or degenerative seems to be dependent on context and timing, as are the windows of opportunity for therapeutic intervention in inflammatory CNS diseases.

Simvastatin ameliorates experimental autoimmune encephalomyelitis by inhibiting Th1/Th17 response and cellular infiltration

AIM

Experimental autoimmune encephalomyelitis (EAE) is a CD4(+)-mediated autoimmune pathology of the central nervous system (CNS) that is used as a model for the study of the human neuroinflammatory disease, multiple sclerosis. During the development of EAE, auto-reactive Th1 and Th17 CD4(+) T cells infiltrate the CNS promoting inflammatory cells recruitment, focal inflammation and tissue destruction. In this sense, statins, agents used to lower lipid levels, have recently shown to exert interesting immunomodulatory function. In fact, statins promote a bias towards a Th2 response, which ameliorates the clinical outcome of EAE. Additionally, simvastatin can inhibit Th17 differentiation. However, many other effects exerted on the immune system by statins have yet to be clarified, in particular during neuroinflammation. Thus, the aim of this study was to investigate the effects of simvastatin on the development of experimental autoimmune encephalomyelitis.

METHODS

Mice were immunized with MOG(35-55) and EAE severity was assessed daily and scored using a clinical scale. Cytokine secretion by mononuclear cells infiltrating the CNS was evaluated by flow cytometry.

RESULTS

Simvastatin (5 mg/kg/day) improved clinical outcome, induced an increase in TGF-β mRNA expression and inhibited IL-6, IL-12p40, IL-12p70, RANTES and MIP-1β secretion (p < 0.05). This was accompanied by a significant decrease in CNS inflammatory mononuclear cell infiltration, with reduced frequencies of both Th1 and Th17 cells. Simvastatin inhibited the proliferation of T lymphocytes co-cultured with primary microglial cells.

CONCLUSIONS

Simvastatin treatment promotes EAE clinical amelioration by inhibiting T cell proliferation and CNS infiltration by pathogenic Th1 and Th17 cells.

A review of the effects of statins in systemic sclerosis

OBJECTIVES

We performed a literature review assessing possible benefits of statins in systemic sclerosis (SSc).

METHODS

PubMed, Embase, Cochrane Databases, and Medline were searched. Full-text English publications were identified in which the effects of statins in SSc were examined. Letters, review articles, and studies on morphea were excluded.

RESULTS

In all, 18 of 404 studies were relevant. In vitro, statins decreased transcription and translation of IL-6 and collagen, with reversal via mevalonate. Animal studies demonstrated reduced production of Ras (a protein superfamily of GTPases), Rho (part of the Ras superfamily), and extracellular signal-regulated kinases (ERK), less fibrosis and myofibroblast transdifferentiation, and improved macrovasculature. In human studies, IL-6, an inflammatory cytokine, was reduced. Usually endothelial progenitor cell concentrations increased, and flow-mediated dilatation improved. Raynaud's phenomenon, digital ulcers, and physician global assessments improved in the majority of studies of statin treatment in SSc. None of the 256 patients receiving statins experienced transaminitis or myopathy.

CONCLUSIONS

Not all findings were consistent. However, in general, in vitro, animal, and human studies demonstrated benefit in SSc pathophysiology, likely mediated through inhibition of lipid intermediate synthesis. Clinical improvement in SSc circulatory complications was observed. Statins seemed safe and well tolerated in SSc. Larger longer-term multi-site randomized trials are needed to further determine the role of statins as adjunctive treatment of this complex, heterogeneous connective tissue disease.

No evidence for an effect on brain atrophy rate of atorvastatin add-on to interferon β1b therapy in relapsing-remitting multiple sclerosis (the ARIANNA study)

BACKGROUND

A previous phase 2 trial has suggested that statins might delay brain atrophy in secondary progressive multiple sclerosis.

OBJECTIVES

The objective of this study was to evaluate the effect of atorvastatin add-on therapy on cerebral atrophy in relapsing-remitting multiple sclerosis.

METHODS

This randomised, placebo-controlled study compared atorvastatin 40 mg or placebo add-on therapy to interferon β1b for 24 months. Brain magnetic resonance imaging, multiple sclerosis functional composite score, Rao neuropsychological battery and expanded disability status scale were evaluated over 24 months.

RESULTS

A total of 154 patients were randomly assigned, 75 in the atorvastatin and 79 in the placebo arms, with a comparable drop-out rate (overall 23.4%). Brain atrophy over 2 years was not different in the two arms (-0.38% and -0.32% for the atorvastatin and placebo groups, respectively). Relapse rate, expanded disability status scale, multiple sclerosis functional composite score or cognitive changes were not different in the two arms. Patients withdrawing from the study had a higher number of relapses in the previous 2 years (P=0.04) and a greater probability of relapsing within 12 months.

CONCLUSIONS

Our results suggest that the combination of atorvastatin and interferon β1b is not justified in early relapsing-remitting multiple sclerosis and adds to the body of evidence indicating an absence of significant radiological and clinical benefit of statins in relapsing-remitting multiple sclerosis.

Body fluid biomarkers for multiple sclerosis--the long road to clinical application

There is a strong unmet clinical need for objective body fluid biomarkers to assist early diagnosis and estimate long-term prognosis, monitor treatment response and predict potential adverse effects in multiple sclerosis (MS). Here, we review recent studies (focusing on 2012 to early 2015) on body fluid markers in MS from the perspective of their clinical utility. Because the first step towards clinical implementation of a newly discovered biomarker is independent replication, we focus on biomarkers that have been validated in at least two independent cohorts. We also discuss recent data challenging earlier findings, and biomarkers for which new clinical uses are suggested. For early MS diagnosis and prediction of conversion from clinically isolated syndrome to MS, several new B-cell-associated candidate blood biomarkers have emerged. For prognosis, several novel axonal damage markers should be adopted to biomarker panels. The number of disease-modifying treatments for MS has increased sharply, but biomarkers for treatment response monitoring and adverse effect prediction are scarce, and markers for subtyping and staging of MS are still lacking. In view of the availability and implementation of several standardized protocols to optimize biomarker studies, we expect biomarker development for MS to be improved and accelerated, with clinical implementation in the near future.

Whole Brain Volume Measured from 1.5T versus 3T MRI in Healthy Subjects and Patients with Multiple Sclerosis

BACKGROUND

Whole brain atrophy is a putative outcome measure in monitoring relapsing‐remitting multiple sclerosis (RRMS). With the ongoing MRI transformation from 1.5T to 3T, there is an unmet need to calibrate this change. We evaluated brain parenchymal volumes (BPVs) from 1.5T versus 3T in MS and normal controls (NC).

METHODS

We studied MS [n = 26, age (mean, range) 43 (21‐55), 22 (85%) RRMS, Expanded Disability Status Scale (EDSS) 1.98 (0‐6.5), timed 25 foot walk (T25FW) 5.95 (3.2‐33.0 seconds)] and NC [n = 9, age 45 (31‐53)]. Subjects underwent 1.5T (Phillips) and 3T (GE) 3‐dimensional T1‐weighted scans to derive normalized BPV from an automated SIENAX pipeline. Neuropsychological testing was according to consensus panel recommendations.

RESULTS

BPV‐1.5T was higher than BPV‐3T [mean (95% CI) + 45.7 mL (+35.3, +56.1), P < .00001], most likely due to improved tissue‐CSF contrast at 3T. BPV‐3T showed a larger volume decrease and larger effect size in detecting brain atrophy in MS versus NC [−74.5 mL (−126.5, −22.5), P = .006, d = .92] when compared to BPV‐1.5T [−51.3.1 mL (−99.8, −2.8), P = .04, d = .67]. Correlations between BPV‐1.5T and EDSS (r = −.43, P = .027) and BPV‐3T and EDSS (r = −.49, P = .011) and between BPV‐1.5T and T25FW (r = −.46, P = .018) and BPV‐3T and T25FW (r = −.56, P = .003) slightly favored 3T. BPV‐cognition correlations were significant (P < .05) for 6 of 11 subscales to a similar degree at 1.5T (r range = .44‐.58) and 3T (r range = .43‐.53).

CONCLUSIONS

Field strength may impact whole brain volume measurements in patients with MS though the differences are not too divergent between 1.5T and 3T.

Spinal cord MRI in multiple sclerosis--diagnostic, prognostic and clinical value

Multiple sclerosis (MS) is an inflammatory disorder of the CNS that affects both the brain and the spinal cord. MRI studies in MS focus more often on the brain than on the spinal cord, owing to the technical challenges in imaging this smaller, mobile structure. However, spinal cord abnormalities at disease onset have important implications for diagnosis and prognosis. Furthermore, later in the disease course, in progressive MS, myelopathy becomes the primary characteristic of the clinical presentation, and extensive spinal cord pathology--including atrophy, diffuse abnormalities and numerous focal lesions--is common. Recent spinal cord imaging studies have employed increasingly sophisticated techniques to improve detection and quantification of spinal cord lesions, and to elucidate their relationship with physical disability. Quantitative MRI measures of cord size and tissue integrity could be more sensitive to the axonal loss and other pathological processes in the spinal cord than is conventional MRI, putting quantitative MRI in a key role to elucidate the association between disability and spinal cord abnormalities seen in people with MS. In this Review, we summarize the most recent MS spinal cord imaging studies and discuss the new insights they have provided into the mechanisms of neurological impairment. Finally, we suggest directions for further and future research.

Liver X receptors and cholesterol metabolism: role in ventral midbrain development and neurodegeneration

The development of the ventral midbrain is orchestrated by a number of cell-extrinsic and -intrinsic factors that control critical processes, such as the patterning of the neural tube along the main body axis and the specification of diverse neuronal cell types in distinct positions of the neural tube. Subsequently, the regulation of neurogenesis and survival— acquire particular relevance in order to define the final size of diverse neuronal populations. In a series of studies during the last few years, we have identified liver X receptors (LXRs) as critical regulators of ventral midbrain development. Moreover, specific cholesterol derivatives present in the midbrain or in the cerebrospinal fluid were identified as LXR ligands, capable of specifically and selectively regulating neurogenesis and the survival of distinct neuronal populations, including midbrain dopamine neurons. These studies have shown that cholesterol derivatives are an entirely new class of factors capable of regulating both neuronal survival and neurogenesis, thus providing a direct link between cholesterol metabolism and brain development. In addition, LXRs and cholesterol metabolism were found to play a critical role in regulating the balance between neuronal survival and death in diverse midbrain neuronal populations. In this review, we will focus on these two aspects and on the possible role of cholesterol metabolism and LXRs in neurodegeneration.

(11)C-PBR28 imaging in multiple sclerosis patients and healthy controls: test-retest reproducibility and focal visualization of active white matter areas

PURPOSE

Activated microglia play a key role in inflammatory demyelinating injury in multiple sclerosis (MS). Microglial activation can be measured in vivo using a positron emission tomography (PET) ligand (11)C-PBR28. We evaluated the test-retest variability (TRV) and lesion detectability of (11)C-PBR28 binding in MS subjects and healthy controls (HCs) with high-resolution PET.

METHODS

Four clinically and radiologically stable relapsing-remitting MS subjects (age 41 ± 7 years, two men/two women) and four HCs (age 42 ± 8 years, 2 two men/two women), matched for translocator protein genotype [two high- and two medium-affinity binders according to DNA polymorphism (rs6971) in each group], were studied for TRV. Another MS subject (age 41 years, male) with clinical and radiological activity was studied for lesion detectability. Dynamic data were acquired over 120 min after injection of 634 ± 101 MBq (11)C-PBR28. For the TRV study, subjects were scanned twice, on average 1.4 weeks apart. Volume of distribution (V T) derived from multilinear analysis (MA1) modeling (t* = 30 min, using arterial input data) was the main outcome measure.

RESULTS

Mean test V T values (ml cm(-3)) were 3.9 ± 1.4 in the whole brain gray matter (GM), 3.6 ± 1.2 in the whole brain white matter (WM) or normal-appearing white matter (NAWM), and 3.3 ± 0.6 in MS WM lesions; mean retest V T values were 3.7 ± 1.0 in GM, 3.3 ± 0.9 in WM/NAWM, and 3.3 ± 0.7 in MS lesions. Test-retest results showed a mean absolute TRV ranging from 7 to 9 % across GM, WM/NAWM, and MS lesions. High-affinity binders demonstrated 30 % higher V T than medium-affinity binders in GM. Focal (11)C-PBR28 uptake was detected in two enhancing lesions of the active MS patient.

CONCLUSION

High-resolution (11)C-PBR28 PET can visualize focal areas where microglial activation is known to be present and has good test-retest reproducibility in the human brain. (11)C-PBR28 PET is likely to be valuable for monitoring both MS disease evolution and response to therapeutic strategies that target microglial activation.

Statin treatment in multiple sclerosis: a systematic review and meta-analysis

BACKGROUND

Multiple sclerosis (MS) is a chronic inflammatory disease that leads to progressive disability. Statins [hydroxymethylglutaryl-CoA (HMG-CoA) reductase inhibitors] are widely prescribed drugs in hypercholesterolemia. They exert immunomodulatory and neurotrophic effects and are attractive candidates for MS treatment due to reliable safety profiles and favorable costs. Studies of statins in a murine MS model and in open-label trials in MS have shown decreased disease severity.

OBJECTIVE

Our objective was to assess current evidence to support statin treatment in MS and clinically isolated syndrome (CIS).

METHODS

We conducted a systematic literature review of EMBASE, PubMed, and CINAHL databases, clinical trials registries, and unpublished conference meeting abstracts as well as reference lists between 1 and 8 June 2014 and repeated it on 1 December 2014. Randomized controlled trials (RCTs) of statins, in any form or dosage, as monotherapy or add-on to established therapy in relapsing-remitting MS (RRMS), progressive MS, and CIS were included. Data were extracted using pre-defined fields to measure study quality. Meta-analysis was performed with regards to pre-defined outcome measures of relapse activity, magnetic resonance imaging (MRI) activity, Expanded Disability Status Scale (EDSS) progression, and adverse events using a fixed-effects model due to low heterogeneity between studies.

RESULTS

Eight trials were included in the review [five of statin add-on to interferon (IFN)-β treatment in RRMS, one of statin monotherapy in CIS, one of statin monotherapy in optic neuritis (ON)/CIS, and one of statin monotherapy in secondary progressive MS (SPMS)]. Three trials with eligible characteristics had not been published in peer-reviewed journals and were therefore not included. Due to the low number of trials in CIS and SPMS, meta-analysis of primary outcomes was only performed for RRMS studies. Meta-analysis showed no significant effect of statin add-on to IFNβ therapy. Indeed, a trend towards an increase in disease activity was shown in the statin group with regards to new T2 lesions, proportion of patients with relapse, and whole brain atrophy but not for EDSS progression. In SPMS, statin monotherapy showed significant reduction in brain atrophy and disability progression but no effect on relapse rate. In CIS, a phase II trial showed no difference in relapse activity, MRI activity or risk of MS between statin monotherapy and placebo. In acute ON, statin monotherapy produced better visual outcome but no difference in relapse activity, MRI activity, or risk of MS.

CONCLUSIONS

The pleiotropic effects and effects in the murine model of MS could not be converted to a proven effect in relapsing MS and hence statin therapy either as a monotherapy or in combination with IFNβ treatment for RRMS, and statin monotherapy for CIS cannot at present be recommended. However, indications are that statins may be beneficial in SPMS. The benefit thereof and whether this is due to a direct immunomodulatory and neuroprotective effect warrant further studies.

Targeting remyelination treatment for multiple sclerosis

Since disability in multiple sclerosis (MS) is a product of neurodegeneration and deficient remyelination, the ability to enhance neuroregeneration and myelin regeneration in MS is an enticing goal for MS drug development. In particular, remyelination treatments could promote return of neurological function and also prevent further axonal loss and neurodegeneration in MS due to trophic effects of myelin. The study of remyelination has advanced dramatically in the last several years such that a number of pathways inhibiting remyelination have been discovered, including those involving LINGO-1, Notch-1, hyaluronan, retinoid X receptor, and wnt/ß-catenin. Other approaches such as high throughput drug screening for remyelination drugs have caught fire, with identification of dozens of known drugs with oligodendrocyte maturation stimulatory effects. Several drugs identified through screens and other mechanisms are in the process of being further evaluated for remyelination in MS and MS models. We discuss the potential molecular targets and the variety of mechanisms towards drug identification and development in remyelination for MS.

Clinical trials in progressive multiple sclerosis: lessons learned and future perspectives

Progressive multiple sclerosis is characterised clinically by the gradual accrual of disability independent of relapses and can occur with disease onset (primary progressive) or can be preceded by a relapsing disease course (secondary progressive). An effective disease-modifying treatment for progressive multiple sclerosis has not yet been identified, and so far the results of clinical trials have generally been disappointing. Ongoing advances in the knowledge of pathogenesis, in the identification of novel targets for neuroprotection, and in improved outcome measures could lead to effective treatments for progressive multiple sclerosis. In this Series paper, we summarise the lessons learned from completed clinical trials and perspectives from trials in progress in progressive multiple sclerosis. We review promising clinical, imaging, and biological markers, along with novel designs, for clinical trials. The use of more refined outcomes and truly neuroprotective drugs, coupled with more efficient trial design, has the capacity to deliver a new era of therapeutic discovery in this challenging area.

Development of therapies for autoimmune disease at Stanford: a tale of multiple shots and one goal

The title of this contribution on Immunology at Stanford is purposely ambiguous. One goal is the development of safe and effective therapy for autoimmune diseases. Another definition of goal is to score, and this would ultimately mean the development of an approved drug. Indeed, the efforts in my four decades at Stanford, have included the discovery and subsequent development of a monoclonal antibody to block homing to the inflamed brain, leading to natalizumab, an approved therapeutic for two autoimmune diseases: relapsing-remitting MS and for inflammatory bowel disease. Multiple attempts to develop new therapies for autoimmune disease are described here: The trimolecular complex and the immune synapse serve as one major set of targets, with attempts to inhibit particular major histocompatibility molecules, the variable regions of the T cell receptor, and CD4. Other approaches focusing on antigen-specific tolerance include ongoing attempts with tolerizing DNA vaccines in type 1 diabetes. Finally, the repurposing of popular drugs approved for other indications, including statins and inhibitors of angiotensin converting enzyme is under development and showing promise in the clinic, particularly for secondary progressive multiple sclerosis. The milieu within Stanford Immunology has helped to nurture these efforts to translate discoveries in immunology and to take them from bench to bedside.

Remyelination in multiple sclerosis: what do we know and where are we going?

Multiple sclerosis (MS) patients today have more hope of a good disease outcome with an ever-increasing choice of immunomodulatory therapies to reduce disease relapses, thought to be caused by inflammation within the CNS, leading to axonal demyelination. However, although there has been much progress in this disease phase, there has been little impact on the progressive phase of MS, when neurodegeneration dominates and patients accumulate disability over years. This failure of prevention of progressive disease has led to a frame-shift in research thinking, focusing on neuroprotective strategies such as promotion of remyelination, to be used alongside immunomodulatory therapies. This review discusses this unmet need in MS, in terms of pathology and current knowledge of remyelination and proremyelinating therapies.

A systematic review of the incidence and prevalence of cardiac, cerebrovascular, and peripheral vascular disease in multiple sclerosis

BACKGROUND

Findings regarding the prevalence of vascular comorbidities in multiple sclerosis (MS) are conflicting.

OBJECTIVE

The objective of this review is to estimate the incidence and prevalence of vascular comorbidities and predisposing comorbidities in persons with MS and to assess the quality of the included studies.

METHODS

The PubMed, EMBASE, SCOPUS and Web of Knowledge databases, conference proceedings, and reference lists of retrieved articles were searched. One reviewer abstracted data using a standardized data collection form, while the second reviewer verified the abstraction. Included studies were assessed qualitatively. Quantitatively, we assessed studies using the I² statistic, and conducted meta-analyses for population-based studies only.

RESULTS

The prevalence of hypertension and hyperlipidemia exceeded 10% in the MS population and increased with age. While the prevalence of ischemic heart disease, congestive heart failure, and stroke were less than 5% overall, the prevalence of these conditions exceeded expectations when compared to the general population. Cardiac valvular disease, however, affected the MS population less often than expected. Problems with study quality were common.

CONCLUSION

Despite the relatively high prevalence of some vascular comorbidities in the MS population, important gaps exist in our understanding of their epidemiology. Most of our knowledge is based on studies conducted in a small number of regions.

The problem with repurposing: Is there really an alternative to Big Pharma for developing new drugs for multiple sclerosis?

If it is not feasible to develop licensed drugs to the stage that they can actually be prescribed for a new indication, can we justify, either ethically or economically, the undertaking of proof-of-concept studies using off-patent medications? Without a financial incentive it is very difficult to repurpose off patent drugs for a new indication. Therefore, we need a political solution to allow the repurposing of off-patent drugs by other stakeholders or Big Pharma.

Therapeutic strategies for relapsing-remitting multiple sclerosis: a special focus on reduction of grey matter damage as measured by brain atrophy

In the past two decades, several pathological and radiological findings convincingly demonstrated that damage of the cortical and deep grey matter is a key issue in multiple sclerosis with a significant impact on physical and cognitive disability. Moreover, it has become increasingly evident that the effect of available therapies on the inflammatory white matter damage is not a guarantee of a meaningful effect on the neurodegenerative process mainly affecting the grey matter. Despite the efficacy of all approved disease-modifying drugs should be measured considering such a relevant aspect of the disease, data from clinical trials are few, scattered and heterogeneous. The aim of this review is to summarize the evidence so far acquired on the effect of reducing grey matter damage produced by current and emerging disease-modifying therapies for multiple sclerosis.

Molecular mechanisms underlying the effects of statins in the central nervous system

3-Hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, commonly referred to as statins, are widely used in the treatment of dyslipidaemia, in addition to providing primary and secondary prevention against cardiovascular disease and stroke. Statins’ effects on the central nervous system (CNS), particularly on cognition and neurological disorders such as stroke and multiple sclerosis, have received increasing attention in recent years, both within the scientific community and in the media. Current understanding of statins’ effects is limited by a lack of mechanism-based studies, as well as the assumption that all statins have the same pharmacological effect in the central nervous system. This review aims to provide an updated discussion on the molecular mechanisms contributing to statins’ possible effects on cognitive function, neurodegenerative disease, and various neurological disorders such as stroke, epilepsy, depression and CNS cancers. Additionally, the pharmacokinetic differences between statins and how these may result in statin-specific neurological effects are also discussed.

A role for Apolipoprotein A-I in the pathogenesis of multiple sclerosis

Apolipoprotein A1 (Apo A-I), the most abundant component of high-density lipoprotein (HDL), is an anti-inflammatory molecule, yet its potential role in the pathogenesis of multiple sclerosis (MS) has not been fully investigated. In this study, Western blot analyses of human plasma showed differential Apo A-I expression in healthy controls compared to MS patients. Further, primary progressive MS patients had less plasma Apo A-I than other forms of MS. Using experimental allergic encephalomyelitis (EAE) as a model for MS, Apo A-I deficient mice exhibited worse clinical disease and more neurodegeneration concurrent with increased levels of pro-inflammatory cytokines compared to wild-type animals. These data suggest that Apo A-I plays a role in the pathogenesis of EAE, a model for MS, creating the possibility for agents that increase Apo A-I levels as potential therapies for MS.

Modulation of dendritic cell immunobiology via inhibition of 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase

The maturation status of dendritic cells determines whether interacting T cells are activated or if they become tolerant. Previously we could induce T cell tolerance by applying a 3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) reductase inhibitor (HMGCRI) atorvastatin, which also modulates MHC class II expression and has therapeutic potential in autoimmune disease. Here, we aimed at elucidating the impact of this therapeutic strategy on T cell differentiation as a consequence of alterations in dendritic cell function. We investigated the effect of HMGCRI during differentiation of peripheral human monocytes and murine bone marrow precursors to immature DC in vitro and assessed their phenotype. To examine the stimulatory and tolerogenic capacity of these modulated immature dendritic cells, we measured proliferation and suppressive function of CD4+ T cells after stimulation with the modulated immature dendritic cells. We found that an HMGCRI, atorvastatin, prevents dendrite formation during the generation of immature dendritic cells. The modulated immature dendritic cells had a diminished capacity to take up and present antigen as well as to induce an immune response. Of note, the consequence was an increased capacity to differentiate naïve T cells towards a suppressor phenotype that is less sensitive to proinflammatory stimuli and can effectively inhibit the proliferation of T effector cells in vitro. Thus, manipulation of antigen-presenting cells by HMGCRI contributes to an attenuated immune response as shown by promotion of T cells with suppressive capacities.