Disease-associated inflammatory biomarker profiles in blood in different subtypes of multiple sclerosis: Prospective clinical and MRI follow-up study

Alteration of prolyl oligopeptidase and activated α-2-macroglobulin in multiple sclerosis subtypes and in the clinically isolated syndrome

Prolyl oligopeptidase (PREP) has been considered as a drug target for the treatment of neurodegenerative diseases. In plasma, PREP has been found altered in several disorders of the central nervous system including multiple sclerosis (MS). Oxidative stress and the levels of an endogenous plasma PREP inhibitor have been proposed to decrease PREP activity in MS. In this work, we measured the circulating levels of PREP in patients suffering of relapsing remitting (RR), secondary progressive (SP), primary progressive (PP) MS, and in subjects with clinically isolated syndrome (CIS). We found a significantly lower PREP activity in plasma of RRMS as well as in PPMS patients and a trend to reduced activity in subjects diagnosed with CIS, compared to controls. No signs of oxidative inactivation of PREP, and no correlation with the endogenous PREP inhibitor, identified as activated α-2-macroglobulin (α2M*), were observed in any of the patients studied. However, a significant decrease of α2M* was recorded in MS. In cell cultures, we found that PREP specifically stimulates immune active cells possibly by modifying the levels of fibrinogen β, thymosin β4, and collagen. Our results open new lines of research on the role of PREP and α2M* in MS, aiming to relate them to the diagnosis and prognosis of this devastating disease.

Pilot study: elevated circulating levels of the proinflammatory cytokine macrophage migration inhibitory factor in patients with chronic spinal cord injury

OBJECTIVE

To test the hypothesis that the proinflammatory cytokine macrophage migration inhibitory factor (MIF) is elevated in the circulation of patients with chronic spinal cord injury (SCI) relative to uninjured subjects, and secondarily to identify additional immune mediators that are elevated in subjects with chronic SCI.

DESIGN

Prospective, observational pilot study.

SETTING

Outpatient clinic of a department of physical medicine and rehabilitation and research institute in an academic medical center.

PARTICIPANTS

Individuals with chronic (>1y from initial injury) SCI (n=22) and age- and sex-matched uninjured subjects (n=19).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Plasma levels of MIF, as determined by a commercially available multiplex suspension immunoassay. The relationship between MIF levels and clinical/demographic variables was also examined. As a secondary outcome, we evaluated other cytokines, chemokines, and growth factors.

RESULTS

Plasma MIF levels were significantly higher in subjects with chronic SCI than in control subjects (P<.001). Elevated MIF levels were not correlated significantly with any one clinical or demographic characteristic. Subjects with SCI also exhibited significantly higher plasma levels of monokine induced by interferon-gamma/chemokine C-X-C motif ligand 9 (P<.03), macrophage colony stimulating factor (P<.035), interleukin-3 (P<.044), and stem cell growth factor beta (SCGF-β) (P<.016). Among subjects with SCI, the levels of SCGF-β increased with the time from initial injury.

CONCLUSIONS

These data confirm the hypothesis that MIF is elevated in subjects with chronic SCI and identify additional novel immune mediators that are also elevated in these subjects. This study suggests the importance of examining the potential functional roles of MIF and other immune factors in subjects with chronic SCI.

Current status of chemokines in the adult CNS

Chemokines - chemotactic cytokines - are small secreted proteins that attract and activate immune and non-immune cells in vitro and in vivo. It has been suggested that chemokines and their receptors play a role in the central nervous system (CNS), in addition to their well established role in the immune system. We focus here on three chemokines-CXCL12 (C-X-C motif ligand 12), CCL2 (C-C motif ligand 2), and CX3CL1 (C-X-3C motif ligand 1) - and their principal receptors - CXCR4 (C-X-C motif receptor 4), CCR2 (C-C motif receptor 2) and CX3CR1 (C-X-3C motif receptor 1), respectively. We first introduce the classification of chemokines and their G-protein coupled receptors and the main signaling pathways triggered by receptor activation. We then discuss the cellular distribution of CXCL12/CXCR4, CCL2/CCR2 and CX3CL1/CX3CR1 in adult brain and the neurotransmission and neuromodulation effects controlled by these chemokines in the adult CNS. Changes in the expression of CXCL12, CCL2 and CX3CL1 and their respective receptors are also increasingly being implicated in the pathogenesis of CNS disorders, such as Alzheimer's disease, Parkinson's disease, HIV-associated encephalopathy, stroke and multiple sclerosis, and are therefore plausible targets for future pharmacological intervention. The final section thus discusses the role of these chemokines in these pathophysiological states. In conclusion, the role of these chemokines in cellular communication may make it possible: (i) to identify new pathways of neuron-neuron, glia-glia or neuron-glia communications relevant to both normal brain function and neuroinflammatory and neurodegenerative diseases; (ii) to develop new therapeutic approaches for currently untreatable brain diseases.

Elevated serum levels of macrophage migration inhibitory factor are associated with progressive chronic cardiomyopathy in patients with Chagas disease

Clinical symptoms of chronic Chagas disease occur in around 30% of the individuals infected with Trypanosoma cruzi and are characterized by heart inflammation and dysfunction. The pathogenesis of chronic chagasic cardiomyopathy (CCC) is not completely understood yet, partially because disease evolution depends on complex host-parasite interactions. Macrophage migration inhibitory factor (MIF) is a pleiotropic proinflammatory cytokine that promotes numerous pathophysiological processes. In the current study, we investigated the link between MIF and CCC progression.

Immunohistochemical analysis demonstrated MIF overexpression in the hearts from chronically T. cruzi-infected mice, particularly those showing intense inflammatory infiltration. We also found that MIF exogenously added to parasite-infected murine macrophage cultures is capable of enhancing the production of TNF-α and reactive oxygen species, both with pathogenic roles in CCC. Thus, the integrated action of MIF and other cytokines and chemokines may account for leukocyte influx to the infected myocardium, accompanied by enhanced local production of multiple inflammatory mediators. We further examined by ELISA the level of MIF in the sera from chronic indeterminate and cardiomyopathic chagasic patients, and healthy subjects. CCC patients displayed significantly higher MIF concentrations than those recorded in asymptomatic T. cruzi-infected and uninfected individuals. Interestingly, increased MIF levels were associated with severe progressive Chagas heart disease, in correlation with elevated serum concentration of high sensitivity C-reactive protein and also with several echocardiographic indicators of left ventricular dysfunction, one of the hallmarks of CCC. Our present findings represent the first evidence that enhanced MIF production is associated with progressive cardiac impairment in chronic human infection with T. cruzi, strengthening the relationship between inflammatory response and parasite-driven pathology. These observations contribute to unravel the elements involved in the pathogenesis of CCC and may also be helpful for the design of novel therapies aimed to control long-term morbidity in chagasic patients.

The anti-inflammatory effect of melatonin on methamphetamine-induced proinflammatory mediators in human neuroblastoma dopamine SH-SY5Y cell lines

Methamphetamine (METH) is a highly addictive drug that is commonly abused worldwide. This psychostimulant drug causes the disturbances in the dopaminergic and serotonergic neurons of several brain areas. Exposure to METH has been shown to induce oxidative stress, reactive oxygen species, reactive nitrogen species, and neuroinflammation. However, the mechanism underlying METH-induced inflammation in neurons is still unclear. In this study, we investigated whether METH caused inflammatory effects in human dopaminergic neuroblastoma SH-SY5Y cells and whether this effect involved the nuclear factor-κB (NF-κB) transcription factor pathway. The present results showed that METH significantly increased inducible nitric oxide synthase (iNOS) expression in a concentration-dependent manner and significantly increased the levels of tumor necrosis factor (TNF)-α mRNA and phosphorylated NF-κB, which is translocated into the nucleus. Moreover, our results also show that METH downregulated another transcription factor, the nuclear factor erythroid 2-related factor (Nrf2), a transcription factor implicated in the expression of several antioxidant/detoxificant enzymes. Furthermore, we also examined the anti-inflammatory effect of melatonin against these METH-induced neuroinflammatory functions. The results show that melatonin significantly decreases the iNOS protein expression and TNF-α mRNA levels caused by METH. The activation and the level of pNF-κB were decreased while Nrf2 expression was increased when cells were pre-incubated with 100 nM of melatonin. In order to show the relationship between cell death and the increase of iNOS, 100 μM of L-NAME, an iNOS inhibitor pretreatment significantly prevented cell death caused by METH. These results demonstrate, for the first time, that METH directly induces inflammation in neurons via an NF-κB-dependent pathway and that the anti-neuroinflammatory effects of melatonin result from the inhibition of activated NF-κB in parallel with potentiated antioxidant/detoxificant defense by activated Nrf2 pathway.

Effects of interferon β-1a and interferon β-1b monotherapies on selected serum cytokines and nitrite levels in patients with relapsing-remitting multiple sclerosis: a 3-year longitudinal study

OBJECTIVE

Interferon (IFN)β treatment is a mainstay of relapsing-remitting multiple sclerosis (RRMS) immunotherapy. Its efficacy is supposedly a consequence of impaired trafficking of inflammatory cells into the central nervous system and modification of the proinflammatory/antiinflammatory cytokine balance. However, the effects of long-term monotherapy using various IFNβ preparations on cytokine profiles and the relevance of these effects for the therapy outcome have not yet been elucidated.

METHODS

Changes were compared in serum levels of TNFα, IFNγ, interleukin (IL)-6, IL-10 and nitrite between RRMS patients given 3-year treatment with intramuscular IFNβ-1a (30 μg once a week) or subcutaneous IFNβ-1b (250 μg every other day). Only the data from patients who completed the 3-year study (n = 20 and n = 18, respectively) were analyzed.

RESULTS

Three-year IFNβ-1a or IFNβ-1b monotherapy reduced serum nitrite levels by 77 and 71%, respectively, lowered multiple sclerosis relapse annual rate by 70 and 71%, respectively, and significantly and similarly lowered Expanded Disability Status Scale scores in both study groups (by 0.9 on average). The two monotherapies showed little if any effect on cytokine levels and cytokine level ratios after the first year, but exerted diverging effects on these indices later on; the only exception was the IFNγ/IL-6 ratio that showed a monotonous rise in both study groups over the entire study period.

CONCLUSION

During long-term IFNβ monotherapy, the levels of the studied cytokines show no relevance to the course of RRMS and neurological status of patients, whereas there seems to be a link between these clinical indices and the activity of nitric oxide-mediated pathways.

The role of T cell apoptosis in nervous system autoimmunity

Fas is a transmembrane receptor involved in the death program of several cell lines, including T lymphocytes. Deleterious mutations hitting genes involved in the Fas pathway cause the autoimmune lymphoprolipherative syndrome (ALPS). Moreover, defective Fas function is involved in the development of common autoimmune diseases, including autoimmune syndromes hitting the nervous system, such as multiple sclerosis (MS) and chronic inflammatory demyelinating polyneuropathy (CIDP). In this review, we first explore some peculiar aspects of Fas mediated apoptosis in the central versus peripheral nervous system (CNS, PNS); thereafter, we analyze what is currently known on the role of T cell apoptosis in both MS and CIDP, which, in this regard, may be seen as two faces of the same coin. In fact, we show that, in both diseases, defective Fas mediated apoptosis plays a crucial role favoring disease development and its chronic evolution.

Reassessment of blood gene expression markers for the prognosis of relapsing-remitting multiple sclerosis

Despite considerable advances in the treatment of multiple sclerosis, current drugs are only partially effective. Most patients show reduced disease activity with therapy, but still experience relapses, increasing disability, and new brain lesions. Since there are no reliable clinical or biological markers of disease progression, long-term prognosis is difficult to predict for individual patients. We identified 18 studies that suggested genes expressed in blood as predictive biomarkers. We validated the prognostic value of those genes with three different microarray data sets comprising 148 patients in total. Using these data, we tested whether the genes were significantly differentially expressed between patients with good and poor courses of the disease. Poor progression was defined by relapses and/or increase of disability during a two-year follow-up, independent of the administered therapy. Of 110 genes that have been proposed as predictive biomarkers, most could not be confirmed in our analysis. However, the G protein-coupled membrane receptor GPR3 was expressed at significantly lower levels in patients with poor disease progression in all data sets. GPR3 has therefore a high potential to be a biomarker for predicting future disease activity. In addition, we examined the IL17 cytokines and receptors in more detail and propose IL17RC as a new, promising, transcript-based biomarker candidate. Further studies are needed to better understand the roles of these receptors in multiple sclerosis and its treatment and to clarify the utility of GPR3 and IL17RC expression levels in the blood as markers of long-term prognosis.

Proteomics technologies for biomarker discovery in multiple sclerosis

Multiple sclerosis is a disabling inflammatory and neurodegenerative disorder that predominantly affects young adults. There is a great need for biomarkers, which could elucidate pathology as well as provide prognosis of disease progression and therapy response in multiple sclerosis. Rapidly evolving, technology driven applications such as mass spectrometry based proteomics are currently being developed for this purpose. In this review, we will outline the current status of the field and detail a number of the bottlenecks as well as future prospects of this type of biomarker research.

Analysis of proinflammatory and anti-inflammatory cytokine serum concentrations in patients with multiple sclerosis by using a multiplexed immunoassay

We examined cytokines and other inflammatory markers in serum samples from 833 patients with multiple sclerosis and 117 healthy control subjects. A multiplexed immunoassay was used to assess the concentrations of 13 cytokines/inflammatory markers: interferon (IFN)-γ; interleukins (ILs)-1β, 2, 4, 5, 6, 8, 10, 12, and 13; tumor necrosis factor (TNF)-α; IL-2 receptor; and soluble CD40 ligand. Significant increases between patients and control subjects were found for IFN-γ (mean, 7.5 vs 0.4 pg/mL; P = .0002), IL-2 (mean 5.7 vs 1.0 pg/mL; P =.0002), IL-1β (mean, 23.0 vs 11.3 pg/mL; P ≤ .0001), TNF-α (mean, 4.1 vs 1.2 pg/mL; P = .01), IL-4 (mean, 1.4 vs 0.1 pg/mL; P ≤ .0001), IL-10 (mean, 16.8 vs 7.5 pg/mL; P = .03), and IL-13 (mean, 4.5 vs 0.8 pg/mL; P ≤ .0001). Profiling cytokines in multiple sclerosis may help to identify mechanisms involved in the pathogenesis of the disease, aid in monitoring the disease course and in evaluating responses to specific therapies, and, potentially, lead to new therapies directed at cytokines or their receptors.

Cytokine mapping in cerebrospinal fluid and blood in multiple sclerosis patients without oligoclonal bands

Objective: Since there are clinical and genetic differences between MS patients with intrathecal oligoclonal bands (OCB+) in the cerebrospinal fluid (CSF) compared with those without (OCB−), the aim was to find out if OCB− patients showed a different pattern of cytokine immune activation compared with OCB+ patients.

Methods: The study included 25 MS patients (10 OCB− and 15 OCB+) and 13 controls. A panel of cytokines was measured; IL-1β, IL-6, IL-8/CXCL8, IL-10, TNF and GM-CSF in serum, CSF and in supernatants from polyclonally stimulated blood mononuclear cells, where also levels of IL-12p40, IL-13, IL-15, IL-17 and IFN-γ were measured. The concentrations of soluble (s) VCAM-1 and sCD14 were measured in serum and CSF.

Results: In general, there were no extensive differences in cytokine concentrations between the OCB− and OCB+ groups.

Conclusion: OCB− MS patients do not seem to constitute a separate entity concerning inflammatory parameters measured as cytokine concentrations in CSF and blood.