Platelet glutamate uptake and Th1 cells inversely correlate in relapsing/remitting and in progressive multiple sclerosis

BACKGROUND

High affinity sodium-dependent Excitatory Amino Acid Transporters (EAAT), present in glial and neuron cells, clear around 90% of the synaptic cleft released glutamate, and their impaired activity seem to be critical for many neurodegenerative disorders, including Multiple Sclerosis (MS). These transporters are also present in human platelets, and they show molecular and biochemical characteristics similar to those in the CNS.

OBJECTIVES

The aim of this study was to investigate whether EAAT-dependent uptake is present also at the peripheral level in blood of MS patients. Moreover, since platelets (plt) and peripheral blood mononuclear cells (PBMC) share the same intra-corporeal fluid, they might be reciprocally influenced, and the glutamate uptake modulation might be useful as a peripheral "trait-marker" to characterize different clinical courses of MS RESULTS: : Reduced uptake values were found in MS patients compared to healthy controls (HC), as well as significant differences were found across MS clinical courses. Representative saturation curves showed that Vmax was significantly decreased for patients compared to HC. Conversely, dissociation constant of the two reactions appeared similar for MS and HC subjects. Furthermore, clinical forms of MS with mild (benign) prognosis was not affected as fa as concern EAAT uptake. Gender, age, and drug treatments did not impact glutamate uptake efficiency. Interestingly, a negative correlation between EAAT activity and percentage of Th1 cells (CD4+IFNγ+ and CD4+TBET+IFNγ+ cells) was observed, suggesting a relationship between EAAT impairment and a pro-inflammatory environment.

CONCLUSIONS

Interestingly, as shown in the CNS, a relationship between clinical, inflammatory MS features and glutamate clearance can be also assessed in platelets. Moreover, glutamate uptake activity might be an useful biomarker to characterize patients with benign prognosis.

The Peripheral Network between Oxidative Stress and Inflammation in Multiple Sclerosis

Reactive oxygen species (ROS) are mainly produced by microglia and macrophages during inflammation-driven oxidative burst. However, they can in turn affect the reactivity and function of immune cells. For the first time, the relationship between these two key players involved in Multiple Sclerosis (MS) was evaluated at peripheral level. We performed an in-depth immune-phenotypic and functional analysis of MBP (Myelin Basic Protein)-stimulated Peripheral Blood Mononuclear Cells (PBMCs) by flow-cytometry. In addition, blood Coenzyme-Q10 (CoQ10), total, oxidized and reduced forms of glutathione (GSTot, GSSG, GSH), malondialdehyde (MDA), ROS, anti-oxidized-low-density-lipoproteins antibodies (anti-oxLDL), and anti-oxidant-power (PAO) were studied in 31 untreated MS patients (MSnoTP), 23 MS patients (MSTP) treated with Disease Modifying Drugs (DMDs) and 39 matched controls (HC). The focus of our study was the correlation between oxidative stress biomarkers and distribution of immune-phenotypes across the 3 studied groups. In MSnoTP an inverse correlation between MDA and apoptotic cells (CD4+ AnnexinV+TIM3+) was detected (rs= − 0.50, p= 0.01). Ml functional phenotype (CD14+IL6+) and TH17 cells (CD4+IL22+) inversely (rs= − 0.48) and directly (rs= 0.46) correlated (p = 0.01) with Anti-oxLDL antibodies and GSSG, respectively. The latter direct correlation was shown also in MSTP. Notably, in this group, we also detected a direct correlation between CD4+ IL4+ and CD4+ IL25+ (TH2 phenotype) with CoQ10 (rs= 0.54) and GSH (rs= 0.46) (p< 0.03), two crucial anti-oxidants. Again, a direct correlation was found between CD8+ BDNF+ cells (suppressor phenotype) and anti-oxLDL (rs= 0.48, p= 0.03). Surprisingly, we measured an inverse correlation between CD14+ IL10+ cells (M2 immune-regulatory cells) with GSH (rs= − 0.59, p< 0.001). Our findings endorse the idea of a relationship between pro-inflammatory cells and pro-oxidative environment, even at peripheral level. Interestingly, the correlation between CD4+ IL10+cells and a defective anti-oxidant equipment might be regarded as evidence of the involvement of these cells during an inflammatory/oxidative phase that they try to control. The finding of this link only in MSTP patients might suggest that DMDs can provide an alternative way to counteract inflammation, regardless of an absolute increase of these immune-regulatory cells.

TH17-Driven Inflammation is Present in All Clinical Forms of Multiple Sclerosis; Disease Quiescence is Associated with Gata3-Expressing Cells

Multiple Sclerosis (MS) presents in a variety of clinical forms associated with a diverse grade of neurological impairment, different prognosis and, possibly, multiple pathogenic mechanisms. Thus, whereas relapsing-remitting (RR) MS appears to be largely driven by inflammatory processes, neurodegeneration, partially independent from inflammation, drives primary progressive (PP) and secondary progressive (SP) MS. An extensive analysis of neuroinflammation in the different forms of MS was performed by evaluating immunophenotypic and functional parameters in MBP-stimulated T lymphocytes of 103 MS patients (26 benign (BE) MS, 30 RRMS, 33 SPMS and 14 PPMS) and 40 healthy controls (HC). Results showed that: i) IL-17-producing and RORC/γt-expressing CD4+ T cells (TH17 lymphocytes), as well as IL-6 expressing CD14+ cell were augmented in all patients; ii) IL-22-expressing cells were increased in all forms of MS with the exception of PPMS; iii) TGF-β-expressing B cells were increased only in RRMS; and iv) GATA3-, NFATc-1, IL-13-, and IL-25-expressing cells (TH2 lymphocytes) were augmented in RRMS and BEMS patients alone. Data herein indicate a pivotal pathogenic role of TH17-driven inflammation in all clinical forms of MS and suggest that control over disease (RRMS and BEMS) is associated not with lack of inflammation per se, but rather with the activation of immune-mediated anti-inflammatory mechanisms. These results could help the design of novel diagnostic and therapeutic approaches.

A pilot trial of low-dose naltrexone in primary progressive multiple sclerosis

A sixth month phase II multicenter-pilot trial with a low dose of the opiate antagonist Naltrexone (LDN) has been carried out in 40 patients with primary progressive multiple sclerosis (PPMS). The primary end points were safety and tolerability. Secondary outcomes were efficacy on spasticity, pain, fatigue, depression, and quality of life. Clinical and biochemical evaluations were serially performed. Protein concentration of beta-endorphins (BE) and mRNA levels and allelic variants of the mu-opiod receptor gene (OPRM1) were analyzed. Five dropouts and two major adverse events occurred. The remaining adverse events did not interfere with daily living. Neurological disability progressed in only one patient. A significant reduction of spasticity was measured at the end of the trial. BE concentration increased during the trial, but no association was found between OPRM1 variants and improvement of spasticity. Our data clearly indicate that LDN is safe and well tolerated in patients with PPMS.

Procedure for the quantitative evaluation of motor disturbances in cerebellar ataxic patients

Cerebellar ataxia is a complex motor disturbance that involves the planning and execution of movements and reduces movement accuracy and co-ordination. The quantification of ataxic signs is commonly realised through visual examination of motor tasks performed by the patient and assignment of scores to specific items composing the international co-operative ataxia rating scale (ICARS). The present work studied an experimental procedure to characterise specific aspects of motor disturbances in ataxia objectively. Four tests belonging to the ICARS were considered: walking, knee-tibia test, finger-to-nose and finger-to-finger test. Through a kinematic analysis performed during the above tests, specific indices were defined to quantify velocity, linearity, asymmetry, tremor, instability and smoothness of movement or posture. The procedure was applied to five patients with cerebellar ataxia and to ten healthy adult subjects. Results demonstrated that the patients moved significantly more slowly than the healthy subjects (0.67 against 0.97m s(-1) and 0.81 against 1.02 m s(-1), respectively, for straight walk and finger-to-nose tests) and showed poorer linearity and smoothness behaviour. Velocity, linearity, tremor, smoothness and instability indices showed moderate to good correlation with the corresponding ICARS score. Some of these indices can separately evaluate aspects that are combined in single ICARS subscores. It is concluded that the combination of clinical assessments and instrumental evaluations allows a better insight into ataxic patients' motor disturbances and is a useful tool for the definition and follow-up of rehabilitation programmes.

Stiff person syndrome does not always occur with maternal passive transfer of GAD65 antibodies

The authors report the presence of high titer antibodies to glutamic acid decarboxylase (anti-GAD65) until age 24 months in two asymptomatic newborns of a woman with stiff-person syndrome (SPS). No signs of SPS were detectable in the two children at ages 6 and 8 years. This observation indicates that other cofactors are involved in the pathogenesis of SPS.

Late-onset cerebellar ataxia with hypogonadism and muscle coenzyme Q10 deficiency

Two brothers had late-onset progressive ataxia, cerebellar atrophy, and hypergonadotropic hypogonadism associated with coenzyme Q10 (CoQ10) deficiency in skeletal muscle. Both patients improved on high-dose CoQ10 supplementation, stressing the importance of CoQ10 deficiency in the differential diagnosis of cerebellar ataxia, even when onset is late.

Beta endorphin concentrations in PBMC of patients with different clinical phenotypes of multiple sclerosis

The possible link between the opioid peptide beta endorphin and the heterogeneity of the clinical course of multiple sclerosis (MS) was investigated. Peripheral blood mononuclear cells (PBMC) concentrations of beta endorphin were measured in 50 patients in different phases of MS. Thirty nine patients also underwent post-contrast magnetic resonance imaging of the brain. Among MS forms, the highest beta endorphin concentrations were found in PBMC from patients with relapsing remitting MS and the lowest in patients with the progressive forms. Average beta endorphin concentrations were lower, although not significantly, in patients with than in those without magnetic resonance imaging enhanced lesions. These data suggest that beta endorphin may have a role in the downregulation of the inflammatory process.

Immunological markers in multiple sclerosis

Multiple sclerosis (MS) is characterized by the presence in the central nervous system (CNS) of perivascular inflammatory infiltrates containing, among others, autoreactive T cells and activated macrophages. These observations indicate that MS is a T cell-mediated CNS-confined chronic inflammatory demyelinating disease in which the ultimate effector cell is the activated macrophage. The inflammatory process, leading to patchy demyelination and axonal loss, is mainly sustained by pro-inflammatory cytokines that, along with chemokines, adhesion molecules and metalloproteases, modulate at different levels the pathogenic process underlying MS. Due to their central role in MS pathogenesis, "inflammatory" molecules might represent suitable peripheral markers of disease (disease-trait) and/or disease activity (state-trait). However, reliable disease-trait or state-trait immunological markers for MS have not yet been identified. The intrinsic characteristics of these molecules (i.e. autocrine/paracrine activity, short half-life, redundancy) may in part explain their inconsistency as disease markers. Additionally, the unreliability of methodologies and the lack of careful patient stratification can also, at least in part, account for the unsatisfactory results so far obtained.

Cytokines and immunity in multiple sclerosis: the dual signal hypothesis

Multiple sclerosis (MS) is considered an immune-mediated disease of the central nervous system (CNS) sustained by a chronic inflammatory process leading to patchy demyelination and axonal loss. However, the inflammatory triggering event as well as the target of the pathogenic process in MS are still partially unknown. We report evidence that a 'local' inflammatory process occurring in the CNS (considered as a reaction of blood vessels in vascularized living tissue to a local injury leading to the accumulation of fluid and blood cells) along with a concomitant, but possibly unrelated, peripheral inflammatory event may trigger a CNS-specific autoimmune reaction cascade sustaining the MS pathogenesis. In the CNS, inflammatory mediators (mainly cytokines) act either as regulatory (i.e. activation of glial cells, shaping the autoimmune response) or effector molecules (i.e. myelinotoxicity, oligodendrotoxicity). In the periphery, inflammatory cytokines induce, in a bystander fashion, activation of monocytes and T cells. Among this latter cell population there are myelin-specific T cells belonging to the normal 'autoimmune' repertoire that home to the CNS where they may trigger the continuous recruitment of effector cells (macrophages) from the periphery. The concept that two concomitant, but possibly unrelated, inflammatory events, occurring in the CNS and in the periphery, represent the crucial elements sustaining MS, might reveal a more comprehensive view (dual signal hypothesis) of the entire etiopathogenic process underlying this disease.

Beta-endorphin concentrations in peripheral blood mononuclear cells of patients with multiple sclerosis: effects of treatment with interferon beta

CONTEXT

It has been reported that the opioid peptide beta-endorphin (BE) has immunosuppressive effects. Interferon beta (IFN-beta) is a well-established therapy for multiple sclerosis (MS), but immunological mechanisms underlying its beneficial effects in MS are partially undefined.

OBJECTIVES

To determine BE levels in peripheral blood mononuclear cells (PBMCs) of patients with relapsing-remitting MS during different phases of disease activity and the possible modulating effects of IFN-beta treatment on PBMC BE synthesis in patients with MS.

DESIGN

We measured BE levels in blood samples collected from 6 patients with MS who had not experienced clinical changes during the previous 3 months (patients with stable MS) and from 7 patients with MS during a clinical relapse. We also surveyed BE levels in PBMC samples from 8 patients with MS before treatment and for 6 months after the beginning of IFN-beta administration. The control group was 13 healthy subjects.

RESULTS

Low PBMC BE levels were detected in patients with stable MS and in those entering IFN-beta treatment compared with control subjects. Increased BE concentrations were observed in MS patients experiencing a clinical relapse compared with patients with stable MS. During IFN-beta treatment, the levels of BE in PBMC samples from patients with MS increased significantly (after 1 month, P =.02; after 3 months, P =.007; and after 6 months, P =.16).

CONCLUSIONS

A reduction of BE levels was present in patients with clinically inactive MS. Treatment with IFN-beta seems to induce an increase of this opioid in PBMCs of MS patients. The increase of BE concentration during a clinical relapse may represent a possible control mechanism aimed at counterbalancing the inflammatory phase of the disease. Arch Neurol. 2000;57:1178-1181

Occurrence of thyroid autoimmunity in relapsing remitting multiple sclerosis patients undergoing interferon-beta treatment

We analyzed the titer of antithyroid autoantibodies (Abs) and thyroid function in 17 multiple sclerosis (MS) patients undergoing interferon-beta (IFN-beta) treatment and in 40 MS control patients. Basal evaluation revealed normal thyroid function in all patients. Abs were detected in 5 IFN-beta-treated patients (29%) and in 4 MS control patients (10%). Our results indicate that IFN-beta treatment may lead to thyroid autoimmunity. We therefore recommend periodic evaluations of antithyroid Abs and thyroid functionality in IFN-beta-treated MS patients.