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Aim: To provide an up-to-date review of oxidative stress biomarkers in multiple sclerosis and thus identify candidate molecules with greatest promise as biomarkers of diagnosis, disease activity or prognosis., Method: A semi-systematic literature search using PubMed and other databases., Results: Nitric oxide metabolites, superoxide dismutase, catalase, glutathione reductase, inducible nitric oxide synthase, protein carbonyl, 3-nitrotyrosine, isoprostanes, malondialdehyde and products of DNA oxidation have been identified across multiple studies as having promise as diagnostic, therapeutic or prognostic markers in MS., Conclusion: Heterogeneity of study design, particularly patient selection, limits comparability across studies. Further cohort studies are needed, and we would recommend promising markers be incorporated into future clinical trials to prospectively validate their potential.

Objectives: Many studies have shown that nitric oxide (NO) and growth factors including insulin growth factors (IGFs) may be involved in the pathogenesis of multiple sclerosis (MS) and neurodegenerative diseases. Our previous studies suggested a relationship between cerebrospinal fluid (CSF) NO metabolites (nitrates and nitrites, NN(x)) and IGF-1 in patients with progressive encephalopathy, hypsarrhythmia and optic atrophy syndrome., Material and Methods: We examined CSF concentrations of NN(x), IGF-1 and IGF binding protein-2 (IGFBP-2) in 25 controls, 14 patients with MS and 14 patients with amyotrophic lateralis sclerosis (ALS)., Results: There were no significant differences in CSF levels of NN(x), IGF-1 or IGFBP-2 between the groups. CSF IGFBP-2 concentrations correlated significantly with age in controls, which may reflect age-related changes in the blood-brain barrier function., Conclusion: Upregulation of the production of NO and IGF-1 in the brain or spinal cord does not influence CSF levels of these molecules in MS or ALS.

Nitric oxide (NO) molecules have one of the most important roles in the pathogenesis of multiple sclerosis (MS). It has been stated that a continuous and high concentration of NO metabolites in CSF and in the serum of MS patients in relapse may cause toxic damage to myelin and oligodendroglia. The aim of this study was to investigate whether NO is a marker of disease activity and is correlated with other disease activity markers such as active lesions on brain magnetic resonance imaging (MRI) and increased immunoglobulin G (IgG) index. Cerebrospinal fluid (CSF) and peripheral serum (PS) samples were taken from patients with definite MS (n = 24) during relapse and remission and from control subjects (n = 18). The Griess reaction was used to measure the NO metabolites, nitrite and nitrate in CSF and PS. Cranial MRI was carried out with triple dose (0,3 mmol/kg) gadolinium and the IgG index was determined. Nitrite and nitrate concentrations (NNCs) of CSF were 11.16 +/- 8.60 micromol/ml in relapse and 6.72 +/- 3.50 micromol/ml in remission, whereas in PS they were 12.89 +/- 7.62 micromol/ml during relapse and 12.35 +/- 6.62 micromol/ml during remission. In control subjects NNCs in CSF and PS were 7.42 +/- 2.81 micromol/ml and 4.37 +/- 1.63 micromol/ml respectively. NNCs in CSF during relapse period were significantly higher than those of both remission phase and control subjects (p = 0.000). Although serum NNCs did not differ in relapse and remission, they were still higher than normal controls. Validity analysis revealed that NNC measurement in CSF was 71 % specific and 66 % sensitive to disease activity. The most important result was the significant correlation of increased NNCs with the existence of active lesion in cranial MRI and an increase in IgG index (p < 0.05).In conclusion, these results add background data to assist in further outlining the possible role of NO in the pathogenesis of MS. Together with the other markers it may be used as an activity marker in relapses of MS.

Interleukin-6 (IL-6) and nitric oxide (NO) are implicated in the pathology of multiple sclerosis (MS). We have investigated the levels of these mediators in the cerebrospinal fluid (CSF) from 50 patients with MS and 23 control subjects. Mean CSF IL-6 level was higher in the total MS group in comparison with controls, but not significantly, whilst the difference between patients with stable MS and controls reached the level of statistical significance. Mean CSF nitrite/nitrate level was significantly higher in the total MS group compared with the control group, as well as in active MS patients versus controls. There was significant difference neither in the mean CSF IL-6 nor in nitrite/nitrate levels between active and stable MS patients. Interestingly, we observed a significant negative correlation between IL-6 and nitrite/nitrate levels in the CSF in the total MS group. Such a trend existed in both subgroups with active and stable MS, but without reaching the level of statistical significance. Our data further support the involvement of IL-6 and NO in ongoing pathological processes in MS, suggesting their potential interplay within the central nervous system in this disease.

The role of nitric oxide (NO) in multiple sclerosis (MS) is not clear. We found increased cerebrospinal fluid concentrations of the NO degradation products nitrate (NO(x)) in clinically definite MS but not in clinically isolated syndromes. High CSF concentrations of NO(x) correlated with long attack duration. Patients carrying the truncated CC chemokine receptor allele CCR5 Delta32 had lower serum concentration of NO(x) at later attack stages. NO(x) concentrations did not change after methylprednisolone treatment but high concentrations were associated with more pronounced treatment responses. These findings suggest an association of high CSF levels of NO(x) with more severe disease activity in relapsing-remitting MS.

Tumor necrosis factor (TNF-alpha) and IL-10 are key regulators of the T helper (Th)1/Th2 balance, which is critically skewed in many pathological conditions including immune-mediated inflammatory diseases of central nervous system (CNS) such as multiple sclerosis (MS). Nitric oxide (NO) has been reported to have dual effects on CNS pathology, and to play an important role in MS. We performed a cross-sectional study in 17 randomly selected patients during MS flare-up, and compared levels of TNF-alpha, IL-10 and NO in serum and cerebrospinal fluid (CSF) with the serum values of these mediators in two different control groups, healthy subjects and HIV-infected untreated patients. Serum and CSF values of TNF-alpha, IL-10 and NO were higher in MS patients than in the serum of healthy controls. Two MS patients showed increased levels of NO in CSF, with inversion of the NO(SERUM)/NO(CSF) quotient, which is clearly indicative of an intrathecal production of NO. No correlation among the values of both cytokines and NO, and the laboratory parameters analysed in MS patients (IgG index, presence of IgG oligoclonal bands and albumin quotient) was found. The high levels of TNF-alpha and IL-10 (both in serum and CSF) accompanying an MS attack suggest a simultaneous expression of Th1 and Th2 cytokines as opposed to sequential expression of Th1 followed by Th2 as described in the models of experimental autoimmune encephalomyelitis (EAE). Globally, our results support the inherent heterogeneity of the disease.

Multiple sclerosis is a disease characterized by perivascular infiltrates and demyelination of the white matter in the central nervous system. In this study, we compared the serum and cerebrospinal fluid nitric oxide levels before and after methylprednisolone therapy, and during remission period, and investigated the relationship of nitric oxide to the activity of multiple sclerosis. Cerebrospinal fluid and serum nitric oxide levels were measured blind as nitrite plus nitrate, using the nitrate reductase and Griess reaction method in 20 patients with multiple sclerosis before and after corticosteroid therapy, and during remission period, and in 20 control subjects. Mean cerebrospinal fluid and serum nitric oxide levels were highest in the pretreatment group and lowest in the control group. There was no correlation with nitric oxide levels in these two groups. Although corticosteroid therapy did not have any great effect on Expanded Disability Status Scales, it led to a decrease in nitric oxide levels. The possible cause of this might be the inhibition of nitric oxide synthesis by methylprednisolone, or a decrease in multiple sclerosis activity. We conclude that serum or cerebrospinal fluid nitric oxide levels do not reflect the activity in multiple sclerosis.

A growing body of evidence implicates excessive generation of nitric oxide (NO) within the central nervous system (CNS) in multiple sclerosis (MS). The aim of our study is to analyse nitrite and nitrate as end products of NO in the cerebrospinal fluid (CSF) from MS patients and correlate the concentrations with clinicol characteristics of the disease. CSF nitrite and nitrate concentrations were measured after reduction of nitrate, by Griess reaction, in 105 MS potients, 27 patients with non-inflammatory neurological disorders (NIND) and 13 individuals without neurological disorder (Co). Mean CSF nitrite and nitrate concentrations were significantly higher in patients with MS and NIND compared with the Co patients (9.44 and 8.68, respectively, versus 6.85 microM; P=0.0001 and P=0.031, respectively). There was no significant correlation between CSF nitrite and nitrate concentrations and activity, phase, severity and duration of MS. Our data are in agreement with the results of previous studies which have demonstrated raised concentrations of CSF NO metabolites in MS patients, providing further evidence for NO involvement in MS. The lack of correlation between NO metabolites and disease activity speaks in favour of the possible dual role of NO, as both immunoregulatory and pro-inflammatory molecule, in the pathogenesis of MS.

Nitric oxide is formed from L-arginine by a family of enzymes: nitric oxide synthase (NOS). The inducible nitric oxide synthase is activated by cytokines and it has been suggested that activation of the enzyme gives rise to neurotoxic levels of reactive nitrogen oxides. This enzyme has been shown to be localized in multiple sclerosis (MS) lesions but the role of nitric oxide formation in the pathogenesis of MS is still unclear. Using capillary electrophoresis, we have analysed nitrite and nitrate in cerebrospinal fluid (CSF) and demonstrate increased levels of reactive nitrogen products in 17 patients with MS. The total levels of oxidized nitrogen products were significantly elevated in MS patients when compared with controls. In patients with active MS, nitrite levels were significantly increased when compared with controls and patients in remission. This is supportive of NOS induction in MS. We suggest that capillary electrophoresis analysis of nitrite and nitrate in CSF could provide a clinically useful way to determine disease activity in MS., (Copyright Lippincott Williams & Wilkins)