The neurobiology of multiple sclerosis: genes, inflammation, and neurodegeneration

Genetic Association and Altered Gene Expression of CYBB in Multiple Sclerosis Patients

Multiple sclerosis (MS) is a chronic neurological disorder characterized by inflammation, demyelination, and axonal damage. Increased levels of reactive oxygen species (ROS), produced by macrophages and leading to oxidative stress, have been implicated as mediators of demyelination and axonal injury in both MS and experimental autoimmune encephalomyelitis, the murine model of the disease. On the other hand, reduced ROS levels can increase susceptibility to autoimmunity. In this work, we screened for association with MS 11 single nucleotide polymorphisms (SNPs) and two microsatellite markers in the five genes (NCF1, NCF2, NCF4, CYBA, and CYBB) of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase (NOX2) system, the enzymatic pathway producing ROS in the brain and neural tissues, in 347 Finnish patients with MS and 714 unaffected family members. This analysis showed suggestive association signals for NCF1 and CYBB (lowest p = 0.038 and p = 0.013, respectively). Functional relevance for disease predisposition was further supported for the CYBB gene, by microarray analysis in CD4^+/− mononuclear cells of 21 individuals from five Finnish multiplex MS families, as well as by real-time RT-PCRs performed on RNA extracted from peripheral blood mononuclear cells of an Italian replication cohort of 21 MS cases and 21 controls. Our results showed a sex-specific differential expression of CYBB, suggesting that this gene, and more in general the NOX2 system, deserve to be further investigated for their possible role in MS.

Association Between IL7R Promoter Polymorphisms and Multiple Sclerosis in Turkish Population

Multiple sclerosis (MS) is a chronic progressive neurodegenerative disease that affects myelin fibers within the central nervous system resulting in neurological impairment. Although the etiology of MS is not fully understood, environmental and genetic factors are thought to play important roles. IL7R gene polymorphisms which are associated with several autoimmune diseases have also been implicated as a genetic factor for MS following genome-wide association studies. To further examine this association, we investigated the association between MS and IL7R gene - 449 (A/G), - 504 (T/C), and - 1085 (G/T) promoter polymorphisms in Turkish population. Three hundred sixty-four MS patients and 191 healthy controls were involved in this study. Three polymorphic regions in the promoter of IL7R were identified and these regions were amplified by appropriate primers. The PCR products were digested by PstI enzyme for - 504 (T/C) SNP and HphI enzyme for - 1085 (G/T) and - 449 (A/G) SNPs and genotyping was done based on digested PCR product sizes. Genotype distributions and allele frequencies of - 449 polymorphism did not show any significant association with MS directly (p = 0.120 and p = 0.490, respectively). But the genotypes of IL7R - 449 GA for AOMS and AA for EOMS were a risk factor in according to age of onset (p = 0.002, OR = 4.021, 95% CI = 1.642-9.845). Furthermore, IL7R - 449 A allele was found to be a risk factor for EOMS (p = 0.011, OR = 1.3, 95% CI = 1.107-1.527). Significant association was seen between IL7R - 504 TC heterozygote genotype and MS (p = 0.02, OR = 1.702, 95% CI = 1.169-2.478). The IL7R - 1085 (G/T) polymorphism did not show association with MS; however, the haplotype of ACG may be susceptibility to MS and RRMS (p = 0.035, OR = 1.349, 95% CI = 1.020-1.785, and p = 0.041, OR = 1.368, 95% CI = 1.012-1.850, respectively) and the haplotypes of ACG, ATT, and GTG demonstrate a protective effect in EOMS (p = 0.008, OR = 0.326, 95% CI = 0.136-0.782, p = 0.012 and p = 0.012, OR = 0.462, 95% CI = 0.249-0.859, respectively). RRMS frequency in the Turkish population was decreased and SPMS frequency was strongly increased based on comparison to results from other populations. Furthermore, male patients had an increased frequency of SPMS significantly (p = 0.033, OR = 1.667, 95% CI = 1.036-2.682). In conclusion, this is the first study to show a significant association between the IL7R promoter polymorphisms and the age of onset of MS.

Ability of Swept-Source Optical Coherence Tomography to Detect Retinal and Choroidal Changes in Patients with Multiple Sclerosis

Purpose

To evaluate the ability of new swept-source (SS) optical coherence tomography (OCT) technology to detect changes in retinal and choroidal thickness in patients with multiple sclerosis (MS).

Methods

A total of 101 healthy and 97 MS eyes underwent retinal and choroidal assessment using SS Triton OCT (Topcon). Macular thickness and peripapillary data (retinal, ganglion cell layer (GCL+, GCL++) and retinal nerve fiber layer (RNFL) thickness) were analyzed, including choroidal thickness evaluation.

Results

Significant macular thinning was observed in all ETDRS areas (p < 0.001) in MS patients. Peripapillary retinal, RNFL, and GCL ++ thickness showed a significant reduction in patients in all sectors (p < 0.001) except in the nasal quadrant/sector (p > 0.05). GCL+ measurements were found to be reduced in the nasal (p=0.003), inferonasal (p=0.045), and temporal (p=0.001) sectors and total thickness (p < 0.001). Choroidal thickness was reduced in the outer macular ring in MS patients compared with controls (p=0.038).

Conclusion

New swept-source technology for OCT devices detects retinal thinning in MS patients, providing increased depth analysis of the choroid in these patients. MS patients present reduced retinal and choroidal thickness in the macular area and reduced peripapillary retinal, RNFL, and GCL thickness.

Integration of Biomarkers Into a Signature Profile of Persistent Traumatic Brain Injury Involving Autoimmune Processes Following Water Hammer Injury From Repetitive Head Impacts

OBJECTIVES

To assemble an algorithm that will describe a "Signature" predictive of an individual's vulnerability to persistent traumatic brain injury (TBI).

SUBJECTS AND METHODS

Studies of athletes and warriors who are subjected to repeated head impacts with rapid acceleration/deceleration forces are used to assist in the diagnosis and management of TBI-affected individuals. Data from multiple areas, including clinical, anatomical, magnetic resonance imaging, cognitive function, and biochemical analyses, are integrated to provide a Signature of persistent TBI.

RESULTS

Studies to date indicate that susceptibility to TBI results from an interaction between host genetic and structural vulnerability factors and force and torque of impact on the head and torso. The host factors include molecular markers affecting immune and inflammatory responses to stress/insult as well as anatomical features such as the degree of transcortical fiber projections and vascular malformations. The host response to forceful impact includes the release of intracellular neural proteins and nucleic acids into the cerebrospinal fluid and vascular compartment as well as mobilization of cytokines and macrophages into the central nervous system with subsequent activation of microglia and inflammatory responses including autoimmune processes. Maximum impact to the base of the sulci via a "water hammer effect" is consistent with the localization of microvascular and inflammatory responses in the affected brain region.

CONCLUSIONS

An assessment of an individuals' predisposition to persistent TBI with delayed cognitive deficits and behavioral changes requires an understanding of host vulnerability (genetic factors and brain structure) and external stressors (force and torque of impact as well as repetitive head injury and time interval between impacts). An algorithm that has utility in predicting vulnerability to TBI will include qualitative and quantitative measures of the host factors weighted against post impact markers of neural injury. Implementation of the resulting "Signature" of vulnerability at early stages of injury will help inform athletes and warriors, along with commanders and management, of the risk/benefit approaches that will markedly diminish health care costs to the nation and suffering to this population. This report attempts to define a strategy to create such an algorithm.

Sirtuins in Neuroendocrine Regulation and Neurological Diseases

Silent information regulator 1 (SIRT1) is a mammalian homolog of the nicotinamide adenine dinucleotide (NAD)-dependent deacetylase sirtuin family. Sirtuin was originally studied as the lifespan-extending gene, silent information regulator 2 (SIRT2) in budding yeast. There are seven mammalian homologs of sirtuin (SIRT1–7), and SIRT1 is the closest homolog to SIRT2. SIRT1 modulates various key targets via deacetylation. In addition to histones, these targets include transcription factors, such as forkhead box O (FOXO), Ku70, p53, NF-κB, PPAR-gamma co-activator 1-alpha (PGC-1α), and peroxisome proliferator-activated receptor γ (PPARγ). SIRT1 has many biological functions, including aging, cell survival, differentiation, and metabolism. Genetic and physiological analyses in animal models have shown beneficial roles for SIRT1 in the brain during both development and adulthood. Evidence from in vivo and in vitro studies have revealed that SIRT1 regulates the cellular fate of neural progenitors, axon elongation, dendritic branching, synaptic plasticity, and endocrine function. In addition to its importance in physiological processes, SIRT1 has also been implicated in protection of neurons from degeneration in models of neurological diseases, such as traumatic brain injury and Alzheimer’s disease. In this review, we focus on the role of SIRT1 in the neuroendocrine system and neurodegenerative diseases. We also discuss the potential therapeutic implications of targeting the sirtuin pathway.

Functional Connectivity in Multiple Sclerosis: Recent Findings and Future Directions

Multiple sclerosis is a debilitating disorder resulting from scattered lesions in the central nervous system. Because of the high variability of the lesion patterns between patients, it is difficult to relate existing biomarkers to symptoms and their progression. The scattered nature of lesions in multiple sclerosis offers itself to be studied through the lens of network analyses. Recent research into multiple sclerosis has taken such a network approach by making use of functional connectivity. In this review, we briefly introduce measures of functional connectivity and how to compute them. We then identify several common observations resulting from this approach: (a) high likelihood of altered connectivity in deep-gray matter regions, (b) decrease of brain modularity, (c) hemispheric asymmetries in connectivity alterations, and (d) correspondence of behavioral symptoms with task-related and task-unrelated networks. We propose incorporating such connectivity analyses into longitudinal studies in order to improve our understanding of the underlying mechanisms affected by multiple sclerosis, which can consequently offer a promising route to individualizing imaging-related biomarkers for multiple sclerosis.

[Care pathway diversity of patients with multiple sclerosis between French regions]

BACKGROUND

The aim of this study is to analyze and to compare data from 2015, focusing on hospital care for patients with multiple sclerosis from three French regions with different characteristics in terms of prevalence, size and number of multiple sclerosis competencies and resource centers.

METHODS

All hospital admissions from the PMSI MCO 2015 database, with a principal or related diagnosis (PD-RD) of G35* ("multiple sclerosis") were extracted. We also extracted chemotherapy treatments administered in hospital, during admissions with a significant associated diagnosis (SAD) of G35*, if the PD or RD was coded Z512 ("non-tumor chemotherapy"). The analyzed regions corresponded to those of 2015, some of which have since merged.

RESULTS

There were 95,359 hospital admissions for multiple sclerosis in France in 2015 among a total cohort of 21,102 patients, resulting in a total cost of € 54.1m. Patients with MS were managed mainly in the ambulatory setting, which accounted for 88.5 % of all admissions. The Rhône-Alpes region represented 7.6 % of national admissions for MS, 9.6 % of patients, and 14 % of inpatient days, contributing 10.4 % of the national cost of MS care. 58.4 % of stays were managed by the two main multiple sclerosis centers. The Nord-Pas-de-Calais region represented 9.8 % of national admissions, 10 % of patients, 6.6 % of inpatient days, and 9.1 % of the national cost. 29.8 % of stays were managed by the main multiple sclerosis center. The Centre region represented 2.7 % of stays, 2.8 % of patients, 3.1 % of inpatient days, and 2.8 % of the national cost. 28.4 % of stays were managed by the main multiple sclerosis center.

CONCLUSION

This study highlights the diversity of multiple sclerosis hospital management and care between these three regions.

Multiple sclerosis prevalence study: The comparison of 3 coastal cities, located in the black sea and mediterranean regions of Turkey

The prevalence of multiple sclerosis (MS) has significantly increased all over the world. Recent studies have shown that Turkey has quite a high prevalence. The aim of this study is to estimate prevalence in the Mediterranean and Black Sea regions of Turkey and to compare the results.This study was designed as a door to door survey in 3 cities. One is located in the Mediterranean region (South), 2 are located in the Black Sea region (North). A previous validated form was used for screening in the field. The patients were examined first in the field, then in the regional health facility. McDonald criteria were used for the diagnosis.In total, 26 patients were diagnosed with MS. The prevalence was found to be 18.6/100,000 in Artvin (Black Sea region), 55.5/100,000 in Ordu, (Black Sea region), 52.00/100,000 in Gazipaşa (Mediterranean region). The female/male ratio was 2.25.This study is the first prevalence study which was conducted in the Mediterranean City (South) of Turkey. The prevalence rate was found to be higher than expected in the Mediterranean city of Gazipaşa. The results showed that the prevalence varies from region to region. Latitude difference was not observed.

Human Endogenous Retroviral Envelope Protein Syncytin-1 and Inflammatory Abnormalities in Neuropsychological Diseases

Human endogenous retroviruses (HERVs) comprise approximately 8% of the human genome. Recent studies have considered HERVs as potential pathogenic factors. The majority of HERV genes are mutated and not capable of encoding functional proteins; regardless, some HERV genes, such as HERV-W envelope (env) glycoprotein, are known to have intact open reading frames. The HERV-W element on 7q21.2, which encodes a protein referred to as Syncytin-1, participates in human placental morphogenesis and can activate a pro-inflammatory and autoimmune cascade. Neuropsychological disorders are typically linked to inflammatory abnormalities. In this study, we review that Syncytin-1 has been increasingly involved in the development of neuropsychological disorders, such as schizophrenia and multiple sclerosis (MS). This study also presents inflammation imbalances in schizophrenia and MS. More importantly, we discuss the potential role and molecular mechanisms by which Syncytin-1 regulates inflammatory abnormalities in neuropsychological diseases. In summary, Syncytin-1 activity may represent a novel molecular pathogenic mechanism in neuropyschological diseases, such as schizophrenia and MS.

The Properties of Cytokines in Multiple Sclerosis: Pros and Cons

Multiple sclerosis (MS) is a chronic autoimmune disease that affects the central nervous system and is characterized by demyelination, axonal loss, gliosis and inflammation. The last plays a major role in the onset and propagation of the disease. MS presents with heterogeneous lesions containing a broad range of cells and soluble mediators of the immune system such as T cells, B cells, macrophages, microglia, cytokines, chemokines, antibodies, complement and other toxic substances. This review outlines, analyzes and discusses the different immune mechanisms of MS that are responsible for the initiation and propagation of active lesions, demyelination, axonal injury, remyelination and cell loss as well as the role of cytokines in the disease process. Proinflammatory cytokines such as interleukin-17 (IL-17), IL-22, tumor necrosis factor-α, IL-1, IL-12 and interferon-γ may cause MS through several signaling pathways. Conversely, anti-inflammatory circulating cytokines such as IL-4 and IL-10 are reduced and theoretically can exert a direct protective effect in this condition. Future studies are necessary to develop effective, safe and long-lasting strategies to reduce the abnormal cytokine cascades and to treat MS.

Fear of falling, not falls, impacts leisure-time physical activity in people with multiple sclerosis

BACKGROUND

There is a consensus that physical activity is imperative for people with MS (PwMS). However, regardless of the benefits, many PwMS do not participate in any meaningful physical activity.

AIM

To examine the relationship between leisure-time physical activity with clinical characteristics and common symptoms in PwMS.

METHODS

The sample included 190 PwMS (107 women), mean age 40.8 (S.D = 13.1) and mean disease duration of 6.4 (SD = 8.3) years since diagnosis. Outcome measures included the Godin Leisure-Time Exercise Questionnaire (GLTEQ), Four Square Step Test (FSST), 2-Minute Walk test (2 mWT), Timed Up and Go test (TUG), Timed 25-Foot Walk test (T25FW), fall status, Falls Efficacy Scale International (FES-I), Modified Fatigue Impact Scale (MFIS), walking speed and the Multiple Sclerosis Walking Scale self-reported questionnaire (MSWS-12).

RESULTS

Eighty-six PwMS were classified as active (GLTEQ = 31.6 (S.D = 16.7); 104 were insufficiently active (GLTEQ = 3.0 (S.D = 4.3). Insufficiently active PwMS demonstrated a slower walking speed, elevated fatigue, more concerns of falling and additional walking difficulties compared to active PwMS. Non-significant differences between groups were observed in the TUG, 2 mWT, FSST, T25FWT and fall status. According to the linear regression, by utilizing the FES-I we observed a 12.2% variance related to leisure-time physical activity. The independent variables: EDSS, MSWS-12, fatigue and walking speed were non-significant.

SIGNIFICANCE

The present findings highlight the impact of concern of falling on physical activity in PwMS. This knowledge may represent an opportunity to improve care and enhance physical activity in the MS population.

[Cognitive dysfunction and the progression of neurodegenerative process in patients with multiple sclerosis]

INTRODUCTION

Neurodegeneration (ND) is the basis of the gradual increase in neurological deficit and cognitive impairment in patients with multiple sclerosis (MS). Morphometry of the brain is the method for monitoring of ND. The possibility of using neuropsychological tests for this purpose is being actively discussed.

AIM

To examine the effect of treatment with interferon beta-1b (IFNb-1b) on the development of the neurodegenerative process according to morphometry and cognitive testing.

MATERIAL AND METHODS

Twenty-three patients with relapsing-remitting MS were examined. The control group included 10 healthy people. All patients received IFNb-1b in a dose of 9.6 million IU. EDSS, MSFC, depression and anxiety Beck test, Wechsler test, magnetic resonance imaging (MRI) of the brain, voxel morphometry with FreeSurfer 5.3 were used. The EDSS score was 4.0 before treatment.

RESULTS

In MS patients, MSFC and Wechsler scores were worse in comparison with similar indicators of the control group. Deterioration of neurological status, motor function test and PASAT during exacerbation was identified in 7 patients. Morphometry revealed the increase in hypointense white matter lesions (HWML) (p<0.05) in patients with MS. There was a downward trend in the cortical and subcortical gray matter volume and the increase in ventricular volume. A direct correlation between the amount of HWML and the degree of disability on EDSS scale (p=0.018), the inverse correlation between HWML and Wechsler test, PASAT (p<0.05) were identified. After a year of therapy, there were no statistically significant changes in motor and cognitive functions and no signs of 'pseudoatrophy'.

CONCLUSION

Morphometric data in MS were changed compared to healthy controls. There were correlations between morphometry results, disability and cognitive dysfunction. After a year of IFNb-1b therapy, there were no significant changes in cognitive function and EDSS.

Neurofilaments and 10-year follow-up in multiple sclerosis

BACKGROUND

The role of biomarkers to predict clinical outcome in multiple sclerosis (MS) is still debated.

OBJECTIVE

To test whether cerebrospinal fluid (CSF) light-chain neurofilament (NfL) levels in newly diagnosed patients with MS could predict clinical outcome over a 10-year period.

METHODS

Patients with newly diagnosed MS underwent standardized clinical assessments at baseline and 5 and 10 years of follow-up. Expanded Disability Status Scale (EDSS) progression between assessments was defined as an increase in one point or more if <6 and 0.5 or more if ≥6. CSF obtained at baseline was analyzed for levels of NfL using enzyme-linked immunosorbent assay technology.

RESULTS

A total of 44 patients were included. In all, 35 patients (80%) had relapsing-remitting multiple sclerosis (RRMS). Patients who progressed in EDSS showed a trend for higher median baseline CSF-NfL levels than patients who did not progress after 5 years (947 ng/L vs 246 ng/L, p = 0.05), and although not statistically significant, after 10 years (708 ng/L vs 265 ng/L, p = 0.28). Patients who converted from RRMS to secondary-progressive multiple sclerosis (SPMS) at 5 years had a statistical significant higher median CSF level of NfL (2122 ng/L vs 246 ng/L, p = 0.01).

CONCLUSION

CSF levels of NfL at the time of diagnosis seems to be an early predictive biomarker of long-term clinical outcome and conversion from RRMS to SPMS.

Gpr97/Adgrg3 ameliorates experimental autoimmune encephalomyelitis by regulating cytokine expression

Multiple sclerosis and its primary animal model, experimental autoimmune encephalomyelitis (EAE), are inflammatory diseases of the central nervous system (CNS) characterized by immune-mediated demyelination and neurodegeneration that may be mediated by inhibition of the nuclear factor-κB (NF-κB) signaling pathway. Gpr97, encoded by Adgrg3, has been reported to regulate the activity of NF-κB. In this study, using a previously established Adgrg3-knockout mouse model, we investigated the roles of Gpr97 in the development of autoimmune CNS disease in mice. We found a marked increase in the expression of Adgrg3 in spinal cords of mice with EAE. Adgrg3-deficient (Adgrg3-/-) mice with EAE exhibited increases in peak severity and the cumulative disease score compared with littermate controls, followed by a notable increase of leukocyte infiltration and more extensive demyelination. The percentages of Th1/Th17 cells in the CNS were significantly increased in Adgrg3-/- mice and accompanied by high levels of interleukin (IL)-6, interferon-γ, tumor necrosis factor-α, and IL-17. An in vitro culture assay verified that Gpr97 regulated proinflammatory cytokine production. Taken together, our results show that Gpr97 plays an important role in the development of EAE and may have a therapeutic potential for the treatment of CNS autoimmunity.

Myelin status is associated with change in functional mobility following slope walking in people with multiple sclerosis

Background

The level of myelin disruption in multiple sclerosis patients may impact the capacity for training-induced neuroplasticity and the magnitude of therapeutic response to rehabilitation interventions. Downslope walking has been shown to increase functional mobility in individuals with multiple sclerosis, but it is unclear if myelin status influences therapeutic response.

Objective

The current study aimed to examine the relationship between baseline myelin status and change in functional mobility after a walking intervention.

Methods

The Timed Up and Go test was used to measure functional mobility before and after completion of a repeated, six-session slope walking intervention in 16 participants with relapsing–remitting multiple sclerosis. Multi-component T₂ relaxation imaging was used to index myelin water fraction of overall water content in brain tissue compartments.

Results

Results demonstrated that the ratio of the myelin water fraction in lesion to normal-appearing white matter (myelin water fraction ratio) significantly predicted 31% of the variance in change in Timed Up and Go score after the downslope walking intervention, where less myelin disruption was associated with greater intervention response.

Conclusions

Myelin water content fraction ratio may offer a neural biomarker of myelin to identify potential responders to interventions targeting functional impairments in multiple sclerosis.

Optimization of lipid-assisted nanoparticle for disturbing neutrophils-related inflammation

Inflammation is closely related to the development of many diseases and is commonly characterized by abnormal infiltration of immune cells, especially neutrophils. The current therapeutics of inflammatory diseases give little attention to direct modulation of these diseases with respect to immune cells. Nanoparticles are applied for efficient drug delivery into the disease-related immune cells, but their performance is significantly affected by their surface properties. In this study, to optimize the properties of nanoparticles for modulating neutrophils-related inflammation, we prepared a library of poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PEG-b-PLGA)-based cationic lipid-assisted nanoparticles (CLANs) with different surface PEG density and surface charge. Optimized CLANs for neutrophils targeting were screened in high-fat diet (HFD)-induced type 2 diabetes (T2D) mice. Then, a CRISPR-Cas9 plasmid expressing a guide RNA (gRNA) targeting neutrophil elastase (NE) was encapsulated into the optimized CLAN and denoted as CLAN_pCas9/gNE. After intravenous injection, CLAN_pCas9/gNE successfully disrupted the NE gene of neutrophils and mitigated the insulin resistance of T2D mice via reducing the inflammation in epididymal white adipose tissue (eWAT) and in the liver. This strategy provides an example of abating the inflammatory microenvironment by directly modulating immune cells with nanoparticles carrying genome editing tools.

Optical coherence tomography as a biomarker of neurodegeneration in multiple sclerosis: A review

Neurodegeneration is one the most important pathological factors which contributes to permanent disability in multiple sclerosis (MS). Optical coherence tomography (OCT) measurements of macular ganglion cell layer (mGCL) and retinal nerve fiber layer (RNFL) have been proposed as biomarkers of axonal damage in MS. The aim of this review is to describe the most relevant findings regarding OCT and axonal damage in MS. We have selected studies that describe retina impairment in MS patients, and those which quantitatively assess the relationship between OCT and physical disability, cognitive impairment and relationship between OCT and magnetic resonance imaging (MRI). Results show that there is a relationship between the degree of retinal layers reduction and physical or cognitive disability and degenerative changes in MRI.

Decision-Making in Multiple Sclerosis Patients: A Systematic Review

Background

Multiple sclerosis (MS) is frequently associated with cognitive and behavioural deficits. A growing number of studies suggest an impact of MS on decision-making abilities. The aim of this systematic review was to assess if (1) performance of MS patients in decision-making tasks was consistently different from controls and (2) whether this modification was associated with cognitive dysfunction and emotional alterations.

Methods

The search was conducted on Pubmed/Medline database. 12 studies evaluating the difference between MS patients and healthy controls using validated decision-making tasks were included. Outcomes considered were quantitative (net scores) and qualitative measurements (deliberation time and learning from feedback).

Results

Quantitative and qualitative decision-making impairment in MS was present in 64.7% of measurements. Patients were equally impaired in tasks for decision-making under risk and ambiguity. A correlation to other cognitive functions was present in 50% of cases, with the highest associations in the domains of processing speed and attentional capacity.

Conclusions

In MS patients, qualitative and quantitative modifications may be present in any kind of decision-making task and can appear independently of other cognitive measures. Since decision-making abilities have a significant impact on everyday life, this cognitive aspect has an influential importance in various MS-related treatment settings.

Staging of cortical and deep grey matter functional connectivity changes in multiple sclerosis

OBJECTIVE

Functional connectivity is known to increase as well as decrease throughout the brain in multiple sclerosis (MS), which could represent different stages of the disease. In addition, functional connectivity changes could follow the atrophy pattern observed with disease progression, that is, moving from the deep grey matter towards the cortex. This study investigated when and where connectivity changes develop and explored their clinical and cognitive relevance across different MS stages.

METHODS

A cohort of 121 patients with early relapsing-remitting MS (RRMS), 122 with late RRMS and 53 with secondary progressive MS (SPMS) as well as 96 healthy controls underwent MRI and neuropsychological testing. Functional connectivity changes were investigated for (1) within deep grey matter connectivity, (2) connectivity between the deep grey matter and cortex and (3) within-cortex connectivity. A post hoc regional analysis was performed to identify which regions were driving the connectivity changes.

RESULTS

Patients with late RRMS and SPMS showed increased connectivity of the deep grey matter, especially of the putamen and palladium, with other deep grey matter structures and with the cortex. Within-cortex connectivity was decreased, especially for temporal, occipital and frontal regions, but only in SPMS relative to early RRMS. Deep grey matter connectivity alterations were related to cognition and disability, whereas within-cortex connectivity was only related to disability.

CONCLUSION

Increased connectivity of the deep grey matter became apparent in late RRMS and further increased in SPMS. The additive effect of cortical network degeneration, which was only seen in SPMS, may explain the sudden clinical deterioration characteristic to this phase of the disease.

Microglial activation and the nitric oxide/cGMP/PKG pathway underlie enhanced neuronal vulnerability to mitochondrial dysfunction in experimental multiple sclerosis

During multiple sclerosis (MS), a close link has been demonstrated to occur between inflammation and neuro-axonal degeneration, leading to the hypothesis that immune mechanisms may promote neurodegeneration, leading to irreversible disease progression. Energy deficits and inflammation-driven mitochondrial dysfunction seem to be involved in this process. In this work we investigated, by the use of striatal electrophysiological field-potential recordings, if the inflammatory process associated with experimental autoimmune encephalomyelitis (EAE) is able to influence neuronal vulnerability to the blockade of mitochondrial complex IV, a crucial component for mitochondrial activity responsible of about 90% of total cellular oxygen consumption. We showed that during the acute relapsing phase of EAE, neuronal susceptibility to mitochondrial complex IV inhibition is markedly enhanced. This detrimental effect was counteracted by the pharmacological inhibition of microglia, of nitric oxide (NO) synthesis and its intracellular pathway (involving soluble guanylyl cyclase, sGC, and protein kinase G, PKG). The obtained results suggest that mitochondrial complex IV exerts an important role in maintaining neuronal energetic homeostasis during EAE. The pathological processes associated with experimental MS, and in particular the activation of microglia and of the NO pathway, lead to an increased neuronal vulnerability to mitochondrial complex IV inhibition, representing promising pharmacological targets.

Diffusion-weighted imaging of normal appearing corticospinal tracts in patients with multiple sclerosis

Aim To determine if there are differences in ADC values between normal appearing corticospinal tracks in patients with MS compared to ADC values in controls. Material and methods The study population comprised 62 consecutive MS patients (36 women and 26 men; mean age 36.45±8.63 years). 50 control subjects with no neurological disabilities or intracranial were included the study (32 women and 18 men; mean age 40.18±12.25 years). All ADC maps were independently evaluated by two experienced radiologists. ROI of approximately 15-18 mm² in capsula interna and 10-12 mm² in mesencephalon were placed bilaterally for measurement of ADC values. Three circular ROIs were placed-one each side for internal capsule-and 6 total ROIs from right and left internal capsule were averaged for each patient. Mesencephelon ADC measurements were performed similarly. Result The mean ADC values of the left internal capsule in MS patients were significiantly lower than the control group (p:0.002). No statistically significant difference was found between the MS patients and control group mean ADC values of the right internal capsule (p>0.05). The mean ADC values of the right and left mesencephalon in MS patients were significiantly lower than the control group (respectively; p:0.031, p<0.001). The mean ADC values of the left internal capsule were significiantly lower than the right internal capsule in MS patients (p<0.001). The mean ADC values of the left mesencephalon were significiantly lower than the right mesencephalon in MS patients (p<0.001). Conclusion The mean ADC values of the normal-appearing corticospinal tract in MS patients were significantly lower than the control group except for the right internal capsule.

Regulator of oligodendrocyte maturation, miR-219, a potential biomarker for MS

Background

Multiple sclerosis (MS) is a demyelinating and degenerative disease of the central nervous system. Normally, demyelination is followed by remyelination, which requires repopulation of a demyelinated area by oligodendrocyte precursor cells. Although large numbers of precursor cells are present in MS lesions, remyelination often fails, in part by the inability of precursor cells to differentiate into mature myelin-forming cells. In mouse and rat, miR-219 is required for this differentiation. Previously, we identified decreased miR-219 expression in tissue of MS patients compared to controls. Cell-free miRNAs have been detected in many different body fluids including cerebrospinal fluid (CSF) and may reflect disease processes going on in the central nervous system. This prompted us to investigate the biomarker performance of CSF miR-219 for MS diagnosis.

Methods

Quantitative PCR was performed measuring miR-219 levels in CSF of MS patients and controls in three independent cohorts.

Results

All three cohorts of MS patients and controls revealed that absence of miR-219 detection in CSF is consistently associated with MS.

Conclusions

We have been able to identify and validate absence of miR-219 detection in CSF of MS patients compared to controls, suggesting that it may emerge as a candidate biomarker for MS diagnosis.

Estimating Memory Deterioration Rates Following Neurodegeneration and Traumatic Brain Injuries in a Hopfield Network Model

Neurodegenerative diseases and traumatic brain injuries (TBI) are among the main causes of cognitive dysfunction in humans. At a neuronal network level, they both extensively exhibit focal axonal swellings (FAS), which in turn, compromise the information encoded in spike trains and lead to potentially severe functional deficits. There are currently no satisfactory quantitative predictors of decline in memory-encoding neuronal networks based on the impact and statistics of FAS. Some of the challenges of this translational approach include our inability to access small scale injuries with non-invasive methods, the overall complexity of neuronal pathologies, and our limited knowledge of how networks process biological signals. The purpose of this computational study is three-fold: (i) to extend Hopfield's model for associative memory to account for the effects of FAS, (ii) to calibrate FAS parameters from biophysical observations of their statistical distribution and size, and (iii) to systematically evaluate deterioration rates for different memory-recall tasks as a function of FAS injury. We calculate deterioration rates for a face-recognition task to account for highly correlated memories and also for a discrimination task of random, uncorrelated memories with a size at the capacity limit of the Hopfield network. While it is expected that the performance of any injured network should decrease with injury, our results link, for the first time, the memory recall ability to observed FAS statistics. This allows for plausible estimates of cognitive decline for different stages of brain disorders within neuronal networks, bridging experimental observations following neurodegeneration and TBI with compromised memory recall. The work lends new insights to help close the gap between theory and experiment on how biological signals are processed in damaged, high-dimensional functional networks, and towards positing new diagnostic tools to measure cognitive deficits.

Multiple sclerosis and HLA genotypes: A possible influence on brain atrophy

BACKGROUND

The strongest genetic determinant for multiple sclerosis (MS) is located at the human leukocyte antigen (HLA) class II DRB1 and DQB1 loci.

OBJECTIVES

To investigate the possible role of predisposing HLA genotypes in determining brain atrophy.

METHODS

HLA genotypes were categorized as high risk (two predisposing haplotypes) or medium/low risk (one or no predisposing haplotypes). Patients underwent a brain magnetic resonance imaging (MRI) study and volumes of white matter (WM), gray matter (GM), and whole brain (WB) were estimated with SIENAX. Longitudinal atrophy was also assessed with SIENA.

RESULTS

The study included 240 MS patients. In 51/240 (21%) subjects, a high-risk HLA genotype was observed, while medium- and low-risk HLA genotypes were 109/240 (45%) and 80/240 (34%), respectively. Multiple regression analysis found that the high-risk HLA genotype was associated with significant reduction in WB ( p = 0.02) and GM ( p = 0.03) volumes compared with the medium-/low-risk HLA genotypes, independently from MS clinical features. The longitudinal study included 60 patients and showed a brain volume loss of -0.79% in high-risk HLA genotype group versus -0.56% in low-risk HLA genotype.

CONCLUSION

Our results suggest an influence of HLA genotype on WB and GM atrophy. Further investigations are necessary to confirm these findings.

Dynamics and heterogeneity of brain damage in multiple sclerosis

Multiple Sclerosis (MS) is an autoimmune disease driving inflammatory and degenerative processes that damage the central nervous system (CNS). However, it is not well understood how these events interact and evolve to evoke such a highly dynamic and heterogeneous disease. We established a hypothesis whereby the variability in the course of MS is driven by the very same pathogenic mechanisms responsible for the disease, the autoimmune attack on the CNS that leads to chronic inflammation, neuroaxonal degeneration and remyelination. We propose that each of these processes acts more or less severely and at different times in each of the clinical subgroups. To test this hypothesis, we developed a mathematical model that was constrained by experimental data (the expanded disability status scale [EDSS] time series) obtained from a retrospective longitudinal cohort of 66 MS patients with a long-term follow-up (up to 20 years). Moreover, we validated this model in a second prospective cohort of 120 MS patients with a three-year follow-up, for which EDSS data and brain volume time series were available. The clinical heterogeneity in the datasets was reduced by grouping the EDSS time series using an unsupervised clustering analysis. We found that by adjusting certain parameters, albeit within their biological range, the mathematical model reproduced the different disease courses, supporting the dynamic CNS damage hypothesis to explain MS heterogeneity. Our analysis suggests that the irreversible axon degeneration produced in the early stages of progressive MS is mainly due to the higher rate of myelinated axon degeneration, coupled to the lower capacity for remyelination. However, and in agreement with recent pathological studies, degeneration of chronically demyelinated axons is not a key feature that distinguishes this phenotype. Moreover, the model reveals that lower rates of axon degeneration and more rapid remyelination make relapsing MS more resilient than the progressive subtype. Therefore, our results support the hypothesis of a common pathogenesis for the different MS subtypes, even in the presence of genetic and environmental heterogeneity. Hence, MS can be considered as a single disease in which specific dynamics can provoke a variety of clinical outcomes in different patient groups. These results have important implications for the design of therapeutic interventions for MS at different stages of the disease.

Multiple Sclerosis (MS) is an autoimmune disease in which inflammatory and degenerative processes damage the brain. We tested the hypothesis that the variability in disease progression and the clinical heterogeneity observed in MS is driven by a single mechanism, namely the autoimmune attack on the CNS that provokes this chronic inflammation and degeneration. As such, it is the difference in the intensity of these processes at distinct times that is responsible for establishing each of the disease subtypes defined to date. Mathematical models of brain damage and disease course were generated that were fitted to clinical data. We found that the phenotypes of the different MS subtypes were reproduced by the model, supporting the concept of a common pathogenesis and thus, that of a single disease in which specific dynamics can produce a variety of clinical outcomes in different groups of patients. These results are likely to be helpful when designing new therapies for this disease.

Wellness and the Role of Comorbidities in Multiple Sclerosis

Multiple sclerosis (MS) is a demyelinating and neurodegenerative disorder of the central nervous system, for which disease modifying therapies (DMTs) are the mainstay treatment approach to reduce inflammatory disease activity and slow worsening disability. In addition to conventional pharmacologic therapy, there is growing interest in the use of lifestyle strategies to support wellness and mitigate disease-related complications in MS. This interest stems from a growing appreciation of the role of certain comorbidities and lifestyle factors on disease activity, disability, mortality, and overall quality of life. While the current literature is not conclusive, there is evidence to suggest a potential role for vitamin D supplementation, tobacco smoking cessation, routine exercise, a plant-based, anti-inflammatory diet, and maintenance of emotional well-being as adjunct therapies to DMTs. In addition to DMTs, lifestyle strategies should be emphasized as part of a management plan focused on overall health and well-being.

Protein tyrosine phosphatase σ regulates autoimmune encephalomyelitis development

Protein tyrosine phosphatases (PTPs) play essential roles in regulating signaling events in multiple cells by tyrosine dephosphorylation. One of them, PTPσ, appears important in regulating function of plasmacytoid dendritic cells (pDC). Here we report that PTPσ deletion in knockout mice and inhibition with a selective antagonist peptide exacerbated symptoms of experimental autoimmune encephalomyelitis (EAE) by enhancing axon and myelin damage in the spinal cord. PTPσ-/- mice displayed pro-inflammatory profiles in the spinal cord and lymphoid organs following MOG peptide immunization. PTPσ deletion promoted a pro-inflammatory phenotype in conventional DCs and directly regulated differentiation of CD4+ T cells. It also facilitated infiltration of T lymphocytes, activation of macrophages in the CNS and development of EAE. Therefore, PTPσ is a key negative regulator in EAE initiation and progression, which acts by regulating functions of DCs, T cells, and other immune cells. PTPσ may become an important molecular target for treating autoimmune disorders.

Healthcare expenditure of multiple sclerosis patients in 2013: A nationwide study based on French health administrative databases

BACKGROUND

Little is known about expenditure items of multiple sclerosis (MS) patients over recent years in France.

OBJECTIVE

To describe healthcare expenditure among MS patients and identify the main expenditure drivers.

METHODS

All healthcare expenditure reimbursed by French National Health Insurance to MS patients in 2013 was described on the basis of nationwide health administrative databases (SNIIRAM/PMSI). Expenditure was described globally and according to age and sex.

RESULTS

The average expenditure among the 90,288 MS patients included was €11,900 per patient. Pharmacy and hospitalisation accounted for 47% and 23% of healthcare expenditure, respectively (38% and 22% of MS patients were treated with disease-modifying therapies and hospitalised overnight or longer, respectively). Average expenditure did not differ according to age. However, pharmacy expenditure decreased with age (from 71% between the ages of 20 and 29 years to 18% between the ages of 70 and 79 years), whereas hospitalisation expenditure increased with age (from 15% to 35%). Paramedical fees accounted for 2% of expenditure between the ages of 20 and 29 years and 24% between the ages of 70 and 79 years.

CONCLUSION

Overall, pharmacy expenditure was the main expenditure item, which decreased with increasing age, while hospitalisation and paramedical expenditure increased with increasing age.

DNA methylation in demyelinated multiple sclerosis hippocampus

Multiple Sclerosis (MS) is an immune-mediated demyelinating disease of the human central nervous system (CNS). Memory impairments and hippocampal demyelination are common features in MS patients. Our previous data have shown that demyelination alters neuronal gene expression in the hippocampus. DNA methylation is a common epigenetic modifier of gene expression. In this study, we investigated whether DNA methylation is altered in MS hippocampus following demyelination. Our results show that mRNA levels of DNA methyltransferase were increased in demyelinated MS hippocampus, while de-methylation enzymes were decreased. Comparative methylation profiling identify hypo-methylation within upstream sequences of 6 genes and hyper-methylation of 10 genes in demyelinated MS hippocampus. Genes identified in the current study were also validated in an independent microarray dataset generated from MS hippocampus. Independent validation using RT-PCR revealed that DNA methylation inversely correlated with mRNA levels of the candidate genes. Queries across cell-specific databases revealed that a majority of the candidate genes are expressed by astrocytes and neurons in mouse and human CNS. Taken together, our results expands the list of genes previously identified in MS hippocampus and establish DNA methylation as a mechanism of altered gene expression in MS hippocampus.

Optogenetics and its application in neural degeneration and regeneration

Neural degeneration and regeneration are important topics in neurological diseases. There are limited options for therapeutic interventions in neurological diseases that provide simultaneous spatial and temporal control of neurons. This drawback increases side effects due to non-specific targeting. Optogenetics is a technology that allows precise spatial and temporal control of cells. Therefore, this technique has high potential as a therapeutic strategy for neurological diseases. Even though the application of optogenetics in understanding brain functional organization and complex behaviour states have been elaborated, reviews of its therapeutic potential especially in neurodegeneration and regeneration are still limited. This short review presents representative work in optogenetics in disease models such as spinal cord injury, multiple sclerosis, epilepsy, Alzheimer's disease and Parkinson's disease. It is aimed to provide a broader perspective on optogenetic therapeutic potential in neurodegeneration and neural regeneration.

Tissue microarray methodology identifies complement pathway activation and dysregulation in progressive multiple sclerosis

The complement pathway has potential contributions to both white (WM) and grey matter (GM) pathology in Multiple Sclerosis (MS). A quantitative assessment of complement involvement is lacking. Here we describe the use of Tissue MicroArray (TMA) methodology in conjunction with immunohistochemistry to investigate the localization of complement pathway proteins in progressive MS cortical GM and subcortical WM. Antibodies targeting complement proteins C1q, C3b, regulatory proteins C1 inhibitor (C1INH, complement receptor 1 (CR1), clusterin, factor H (FH) and the C5a anaphylatoxin receptor (C5aR) were utilised alongside standard markers of tissue pathology. All stained slides were digitised for quantitative analysis. We found that numbers of cells immunolabelled for HLA-DR, GFAP, C5aR, C1q and C3b were increased in WM lesions (WML) and GM lesions (GML) compared to normal appearing WM (NAWM) and GM (NAGM), respectively. The complement regulators C1INH, CR1, FH and clusterin were more abundant in WM lesions, while the number of C1q+ neurons were increased and the number of C1INH+, clusterin+, FH+ and CR1+ neurons decreased in GM lesions. The number of complement component positive cells (C1q, C3b) correlated with complement regulator expression in WM, but there was no statistical association between complement activation and regulator expression in the GM. We conclude that TMA methodology and quantitative analysis provides evidence of complement dysregulation in MS GML, including an association of the numerical density of C1q+ cells with tissue lesions. Our work confirms that complement activation and dysregulation occur in all cases of progressive MS and suggest that complement may provide potential biomarkers of the disease.

Pain, Fatigue, and Cognitive Symptoms Are Temporally Associated Within but Not Across Days in Multiple Sclerosis

OBJECTIVE

To examine the temporal associations, within day and day to day, between pain, fatigue, depressed mood, and cognitive function in multiple sclerosis (MS).

DESIGN

Repeated-measures study involving 7 days of ecological momentary assessment (EMA) of symptoms 5 times a day; multilevel mixed models were used to analyze data.

SETTING

Community.

PARTICIPANTS

Ambulatory adults (N=107) with MS.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

EMA of pain, fatigue, depressed mood, and cognitive function rated on a 0 to 10 scale.

RESULTS

Fatigue and pain were linked within day such that higher pain was associated with higher subsequent fatigue (B=.09, P=.04); likewise, higher fatigue was associated with higher pain in the following time frame (B=.05, P=.04). Poorer perceived cognitive function preceded increased subsequent pain (B=.08, P=.007) and fatigue (B=.10, P=.01) within day. Depressed mood was not temporally linked with other symptoms. In terms of day-to-day effects, a day of higher fatigue related to decreased next day fatigue (B=-.16, P=.01), and a day of higher depressed mood related to increased depressed mood the next day (B=.17, P=.01). There were no cross-symptom associations from one day to the next.

CONCLUSIONS

Findings provide new insights on how common symptoms in MS relate to each other and vary within and over days. Pain and fatigue show evidence of a dynamic bidirectional relation over the course of a day, and worsening of perceived cognitive function preceded worsening of both pain and fatigue. Most temporal associations between symptoms occur within the course of a day, with relatively little carryover from one day to the next.

Ecological Momentary Assessment of Pain, Fatigue, Depressive, and Cognitive Symptoms Reveals Significant Daily Variability in Multiple Sclerosis

OBJECTIVE

To describe the daily variability and patterns of pain, fatigue, depressed mood, and cognitive function in persons with multiple sclerosis (MS).

DESIGN

Repeated-measures observational study of 7 consecutive days of home monitoring, including ecological momentary assessment (EMA) of symptoms. Multilevel mixed models were used to analyze data.

SETTING

General community.

PARTICIPANTS

Ambulatory adults (N=107) with MS recruited through the University of Michigan and surrounding community.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURE

EMA measures of pain, fatigue, depressed mood, and cognitive function rated on a 0 to 10 scale, collected 5 times a day for 7 days.

RESULTS

Cognitive function and depressed mood exhibited more stable within-person patterns than pain and fatigue, which varied considerably within person. All symptoms increased in intensity across the day (all P<.02), with fatigue showing the most substantial increase. Notably, this diurnal increase varied by sex and age; women showed a continuous increase from wake to bedtime, whereas fatigue plateaued after 7 pm for men (wake-bed B=1.04, P=.004). For the oldest subgroup, diurnal increases were concentrated to the middle of the day compared with younger subgroups, which showed an earlier onset of fatigue increase and sustained increases until bed time (wake-3 pm B=.04, P=.01; wake-7 pm B=.03, P=.02). Diurnal patterns of cognitive function varied by education; those with advanced college degrees showed a more stable pattern across the day, with significant differences compared with those with bachelor-level degrees in the evening (wake-7 pm B=-.47, P=.02; wake-bed B=-.45, P=.04).

CONCLUSIONS

Findings suggest that chronic symptoms in MS are not static, even over a short time frame; rather, symptoms-fatigue and pain in particular-vary dynamically across and within days. Incorporation of EMA methods should be considered in the assessment of these chronic MS symptoms to enhance assessment and treatment strategies.

Tissue microarray methodology identifies complement pathway activation and dysregulation in progressive multiple sclerosis

The complement pathway has potential contributions to both white (WM) and grey matter (GM) pathology in Multiple Sclerosis (MS). A quantitative assessment of complement involvement is lacking. Here we describe the use of Tissue MicroArray (TMA) methodology in conjunction with immunohistochemistry to investigate the localization of complement pathway proteins in progressive MS cortical GM and subcortical WM. Antibodies targeting complement proteins C1q, C3b, regulatory proteins C1 inhibitor (C1INH, complement receptor 1 (CR1), clusterin, factor H (FH) and the C5a anaphylatoxin receptor (C5aR) were utilised alongside standard markers of tissue pathology. All stained slides were digitised for quantitative analysis. We found that numbers of cells immunolabelled for HLA-DR, GFAP, C5aR, C1q and C3b were increased in WM lesions (WML) and GM lesions (GML) compared to normal appearing WM (NAWM) and GM (NAGM), respectively. The complement regulators C1INH, CR1, FH and clusterin were more abundant in WM lesions, while the number of C1q+ neurons were increased and the number of C1INH+, clusterin+, FH+ and CR1+ neurons decreased in GM lesions. The number of complement component positive cells (C1q, C3b) correlated with complement regulator expression in WM, but there was no statistical association between complement activation and regulator expression in the GM. We conclude that TMA methodology and quantitative analysis provides evidence of complement dysregulation in MS GML, including an association of the numerical density of C1q+ cells with tissue lesions. Our work confirms that complement activation and dysregulation occur in all cases of progressive MS and suggest that complement may provide potential biomarkers of the disease.

Mesenchymal stem cell-mediated immunomodulation in cell therapy of neurodegenerative diseases

Dysfunction of immune responses has been identified to involve in the pathogenesis of various neurodegenerative diseases. Abnormal activation of glia cells and/or infiltration of peripheral adaptive immune cells always sustains neuroinflammation and the disease progression. Obviously, the regulation of neuroinflammation has become a potential therapeutic strategy against neurodegenerative diseases. Mesenchymal stem cells (MSCs) exhibit complex interactions with various immune cells including T cells, macrophages and especially resident glia cells in the central nervous system. In response to tissue injury signals, MSCs adopt specific phenotype to suppress or promote immune responses depending on the inflammatory microenvironment they reside. Therefore, manipulation of MSCs may hold great potentials to improve MSC-based therapy on neurodegenerative diseases. Here we review MSC-mediated immunomodulation in cell therapy of neurodegenerative diseases, providing fundamental information for guiding appropriate applications of MSCs in clinical settings.

Underlying chronic inflammation alters the profile and mechanisms of acute neutrophil recruitment

Chronically inflamed tissues show altered characteristics that include persistent populations of inflammatory leukocytes and remodelling of the vascular network. As the majority of studies on leukocyte recruitment have been carried out in normal healthy tissues, the impact of underlying chronic inflammation on ongoing leukocyte recruitment is largely unknown. Here, we investigate the profile and mechanisms of acute inflammatory responses in chronically inflamed and angiogenic tissues, and consider the implications for chronic inflammatory disorders. We have developed a novel model of chronic ischaemia of the mouse cremaster muscle that is characterized by a persistent population of monocyte‐derived cells (MDCs), and capillary angiogenesis. These tissues also show elevated acute neutrophil recruitment in response to locally administered inflammatory stimuli. We determined that Gr1^lowMDCs, which are widely considered to have anti‐inflammatory and reparative functions, amplified acute inflammatory reactions via the generation of additional proinflammatory signals, changing both the profile and magnitude of the tissue response. Similar vascular and inflammatory responses, including activation of MDCs by transient ischaemia–reperfusion, were observed in mouse hindlimbs subjected to chronic ischaemia. This response demonstrates the relevance of the findings to peripheral arterial disease, in which patients experience transient exercise‐induced ischaemia known as claudication.These findings demonstrate that chronically inflamed tissues show an altered profile and altered mechanisms of acute inflammatory responses, and identify tissue‐resident MDCs as potential therapeutic targets. © 2016 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Pharmacological Approaches to the Management of Secondary Progressive Multiple Sclerosis

It is well recognised that the majority of the impact of multiple sclerosis (MS), both personal and societal, arises in the progressive phase where disability accumulates inexorably. As such, progressive MS (PMS) has been the target of pharmacological therapies for many years. However, there are no current licensed treatments for PMS. This stands in marked contrast to relapsing remitting MS (RRMS) where trials have resulted in numerous licensed therapies. PMS has proven to be a more difficult challenge compared to RRMS and this review focuses on secondary progressive MS (SPMS), where relapses occur before the onset of gradual, irreversible disability, and not primary progressive MS where disability accumulation occurs without prior relapses. Although there are similarities between the two forms, in both cases pinpointing when PMS starts is difficult in a condition in which disability can vary from day to day. There is also an overlap between the pathology of relapsing and progressive MS and this has contributed to the lack of well-defined outcomes, both surrogates and clinically relevant outcomes in PMS. In this review, we used the search term 'randomised controlled clinical drug trials in secondary progressive MS' in publications since 1988 together with recently completed trials where results were available. We found 34 trials involving 21 different molecules, of which 38% were successful in reaching their primary outcome. In general, the trials were well designed (e.g. double blind) with sample sizes ranging from 35 to 1949 subjects. The majority were parallel group, but there were also multi-arm and multidose trials as well as the more recent use of adaptive designs. The disability outcome most commonly used was the Expanded Disability Status Scale (EDSS) in all phases, but also magnetic resonance imaging (MRI)-measured brain atrophy has been utilised as a surrogate endpoint in phase II studies. The majority of the treatments tested in SPMS over the years were initially successful in RRMS. This has a number of implications in terms of targeting SPMS, but principally implies that the optimal strategy to target SPMS is to utilise the prodrome of relapses to initiate a therapy that will aim to both prevent progression and slow its accumulation. This approach is in agreement with the early targeting of MS but requires treatments that are both effective and safe if it is to be used before disability is a major problem. Recent successes will hopefully result in the first licensed therapy for PMS and enable us to test this approach.

Progressive multiple sclerosis: from pathogenic mechanisms to treatment

During the past decades, better understanding of relapsing-remitting multiple sclerosis disease mechanisms have led to the development of several disease-modifying therapies, reducing relapse rates and severity, through immune system modulation or suppression. In contrast, current therapeutic options for progressive multiple sclerosis remain comparatively disappointing and challenging. One possible explanation is a lack of understanding of pathogenic mechanisms driving progressive multiple sclerosis. Furthermore, diagnosis is usually retrospective, based on history of gradual neurological worsening with or without occasional relapses, minor remissions or plateaus. In addition, imaging methods as well as biomarkers are not well established. Magnetic resonance imaging studies in progressive multiple sclerosis show decreased blood-brain barrier permeability, probably reflecting compartmentalization of inflammation behind a relatively intact blood-brain barrier. Interestingly, a spectrum of inflammatory cell types infiltrates the leptomeninges during subpial cortical demyelination. Indeed, recent magnetic resonance imaging studies show leptomeningeal contrast enhancement in subjects with progressive multiple sclerosis, possibly representing an in vivo marker of inflammation associated to subpial demyelination. Treatments for progressive disease depend on underlying mechanisms causing central nervous system damage. Immunity sheltered behind an intact blood-brain barrier, energy failure, and membrane channel dysfunction may be key processes in progressive disease. Interfering with these mechanisms may provide neuroprotection and prevent disability progression, while potentially restoring activity and conduction along damaged axons by repairing myelin. Although most previous clinical trials in progressive multiple sclerosis have yielded disappointing results, important lessons have been learnt, improving the design of novel ones. This review discusses mechanisms involved in progressive multiple sclerosis, correlations between histopathology and magnetic resonance imaging studies, along with possible new therapeutic approaches.

Novel Chemically-modified DNAzyme targeting Integrin alpha-4 RNA transcript as a potential molecule to reduce inflammation in multiple sclerosis

Integrin alpha-4 (ITGA4) is a validated therapeutic target for multiple sclerosis (MS) and Natalizumab, an antibody targeting ITGA4 is currently approved for treating MS. However, there are severe side effects related to this therapy. In this study, we report the development of a novel DNAzyme that can efficiently cleave the ITGA4 transcript. We designed a range of DNAzyme candidates across various exons of ITGA4. RNV143, a 30mer arm-loop-arm type DNAzyme efficiently cleaved 84% of the ITGA4 mRNA in human primary fibroblasts. RNV143 was then systematically modified by increasing the arm lengths on both sides of the DNAzymes by one, two and three nucleotides each, and incorporating chemical modifications such as inverted-dT, phosphorothioate backbone and LNA-nucleotides. Increasing the arm length of DNAzyme RNV143 did not improve the efficiency however, an inverted-dT modification provided the most resistance to 3′ → 5′ exonuclease compared to other modifications tested. Our results show that RNV143A could be a potential therapeutic nucleic acid drug molecule towards the treatment for MS.