Nitric oxide metabolites in CSF of patients with MS are related to clinical disease course

In this study, we have analyzed the stable metabolites of nitric oxide (NO), nitrite and nitrate, in the CSF of patients with MS, lymphocytic meningitis, and in healthy control subjects. Patients with MS with an active disease course exhibited increased CSF nitrite levels compared with patients with stable MS and healthy control subjects, whereas CSF nitrate levels did not differ between these groups. High CSF levels of both metabolites were seen in patients with meningitis. These data indicate that CSF nitrite levels may reflect clinical disease activity in MS.     

Raised cerebrospinal fluid nitrite and nitrate levels in patients with multiple sclerosis: no correlation with disease activity

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.     

CEREBROSPINAL FLUID NITRITE AND MALONDIALDEHYDE LEVELS IN PATIENTS WITH MOTOR NEURON DISEASE

Nitric oxide (NO) mediated oxidative damage may be involved in the pathogenesis of neuronal degeneration in motor neuron disease (MND). The present study was undertaken to evaluate the role of NO and oxidative stress in MND by estimating nitrite and malondialdehyde (MDA) levels in the cerebrospinal fluid (CSF) in 22 patients of MND and 20 control subjects suffering from neurological disorders not known to affect NO metabolism. There was no significant change in the CSF nitrite and MDA levels in MND. The nitrite and MDA levels did not have any significant correlation with age, duration of illness, or severity of disease.­ Univariate analysis of the clinical features in patients with MND and the nitrite levels revealed that two patients with a positive family history had significantly higher CSF nitrite levels as compared to those with a negative family history. There was no correlation between the CSF nitrite and MDA levels. Results of the present study did not indicate significant alterations in the MDA and NO levels in the CSF of MND patients. However, involvement of NO in MND with positive family history is suggested by the results obtained.­     

Cerebrospinal fluid nitrite and malondialdehyde levels in patients with motor neuron disease

Nitric oxide (NO) mediated oxidative damage may be involved in the pathogenesis of neuronal degeneration in motor neuron disease (MND). The present study was undertaken to evaluate the role of NO and oxidative stress in MND by estimating nitrite and malondialdehyde (MDA) levels in the cerebrospinal fluid (CSF) in 22 patients of MND and 20 control subjects suffering from neurological disorders not known to affect NO metabolism. There was no significant change in the CSF nitrite and MDA levels in MND. The nitrite and MDA levels did not have any significant correlation with age, duration of illness, or severity of disease. Univariate analysis of the clinical features in patients with MND and the nitrite levels revealed that two patients with a positive family history had significantly higher CSF nitrite levels as compared to those with a negative family history. There was no correlation between the CSF nitrite and MDA levels. Results of the present study did not indicate significant alterations in the MDA and NO levels in the CSF of MND patients. However, involvement of NO in MND with positive family history is suggested by the results obtained.     

Nitric oxide metabolite determinations reveal continuous inflammation in multiple sclerosis

Nitric oxide (NO) is formed as a consequence of induction of the iNOS enzyme during inflammatory disorders. To investigate NO production in multiple sclerosis (MS), we determined the concentrations of its oxidation products (NOx) in the cerebrospinal fluid (CSF) and plasma of 61 MS patients. The patients were divided into three groups on the basis of their clinical disease activity. The total levels of NOx in CSF were significantly increased in all MS groups as compared to healthy controls and tension headache patients. CSF nitrite correlated with clinical disease activity. At exacerbation, the CSF nitrite levels exceed the plasma level. This suggests that clinical disease activity is due to a CNS inflammatory response, which is more intense and qualitatively different from that during clinical stable phases. This study supports NO involvement in the pathogenesis of MS and determination of nitrite levels may be useful a surrogate marker for disease activity.     

Cerebrospinal fluid nitric oxide metabolites in painful diseases

To elucidate the involvement of NO in pain transmission in humans, we measured NO metabolites (nitrite/nitrate) in the CSF of patients with painful diseases using an NO analyzer based on the Griess method. The nitrite/nitrate levels in patients with degenerative lumbar disease (DLD), but not those with fracture or appendicitis, were significantly higher than those in an age-matched control group. The duration of pain in the DLD group was much longer than that in the fracture or appendicitis group. The nitrite/nitrate levels in the middle-aged and elderly DLD patients depended on the duration of pain. These data probably suggest that the duration of pain is critical for the elevation in nitrite/nitrate levels.     

No changes in cerebrospinal fluid levels of nitrite, nitrate and cyclic GMP with aging

Summary Nitric oxide (NO) is a free radical gas that plays a role in various signal transduction processes. NO has been proposed to have a function in the mechanism of synaptic plasticity, including long-term potentiation and memory formation in vivo. Because a failure in synaptic plasticity is considered to be involved in aging-associated brain dysfunction, NO production in the brain may be altered by aging. In the present study, we measured the levels of NO metabolites, nitrite and nitrate, and cyclic GMP in the cerebrospinal fluid (CSF) of human subjects without neurological or psychiatric disorders. There were no age-related changes in the CSF levels of either nitrite, nitrate or cyclic GMP. These results suggest that NO production in the brain may be maintained during the aging process.     

Nitric oxide synthase is present in the cerebrospinal fluid of patients with active multiple sclerosis and is associated with increases in cerebrospinal fluid protein nitrotyrosine and S-nitrosothiols and with changes in glutathione levels

Nitric oxide (NO) is hypothesized to play a role in the immunopathogenesis of multiple sclerosis (MS). Increased levels of NO metabolites have been found in patients with MS. Peroxynitrite, generated by the reaction of NO with superoxide at sites of inflammation, is a strong oxidant capable of damaging tissues and cells. Inducible NO synthase (iNOS) is up-regulated in the CNS of animals with experimental allergic encephalomyelitis (EAE) and in patients with MS. In this study, Western blots of cerebrospinal fluid (CSF) from patients with MS demonstrated the presence of iNOS, which was absent in CSF from control subjects. There was also NOS activity present in both MS and control CSF. Total NOS activity was increased (by 24%) in the CSF from MS patients compared with matched controls. The addition of 0.1 mM ITU (a specific iNOS inhibitor) to the samples did not change the activity of the control samples but decreased the NOS activity in the MS samples to almost control levels. The addition of 1 mM L-NMMA (a nonisoform specific NOS inhibitor), completely inhibited NOS activity in CSF from control and MS subjects. Nitrotyrosine immunostaining of CSF proteins was detectable in controls but was greatly increased in MS samples. There were also significant increases in CSF nitrate + nitrite and oxidant-enhanced luminescence in MS samples compared with controls. Additionally, a significant decrease in reduced glutathione and significant increases in oxidized glutathione and S-nitrosothiols were found in MS samples compared with controls. Parallel changes in NO metabolites were observed in the plasma of MS patients, compared with controls, and accompanied a significant increase of reduced glutathione. These data strongly support a role for nitrosative stress in the pathogenesis of MS and indicate that therapeutic strategies focussed on decreasing production of NO by iNOS and/or scavenging peroxynitrite may be useful in alleviating the neurological impairments that occur during MS relapse.     

Serum and cerebrospinal fluid nitrite and nitrate levels in relapsing-remitting and secondary progressive multiple sclerosis patients

Nitric oxide (NO) has been implicated in immune mediated cellular cytotoxicity and inflammatory processes including multiple sclerosis (MS). We aimed to assess NO production in MS patients and to delineate its involvement in different stages. The stable end-products of NO; nitrite(NO₂⁻) and nitrate(NO₃⁻) were analysed both in serum and CSF (cerebrospinal fluid) of patients with MS and non-inflammatory neurological diseases. Nitrite levels were quantified by calorimetric assay based on the Griess reaction. Nitrate levels were examined spectrophotometrically. MS patients exhibited significantly increased serum and CSF levels of NO₂⁻+NO₃⁻ compared with the control subjects. CSF NO₂⁻+NO₃⁻ levels were raised significantly in MS patients with both relapsing remitting (RR) and secondary progressive (SP) course. There was no significant difference between RR and SP MS patients with regard to NO metabolites. No significant correlation was found between NO metabolites and disability score, disease progression index, MRI (magnetic resonance imaging) activity and development of cortical atrophy on MRI. This study provides further evidence for excessive NO production both in CSF and peripheral blood of MS patients. Excessive CSF NO₂⁻+NO₃⁻ levels being more increased than the levels in sera supports pathological inflammatory process within CNS (central nervous system) in both stages of MS. Another implication for the role of NO and INOS inhibitors in the treatment of MS patients with both RR and SP courses was also suggested.     

Low concentration of nitrite and nitrate in the cerebrospinal fluid from schizophrenic patients: a pilot study

Some evidence suggests a dysfunctional nitric oxide (NO) system in the brain of schizophrenic subjects. We measured the concentrations of the stable metabolites of NO, nitrite, and nitrate in the cerebrospinal fluid (CSF) from schizophrenic and control patients with other neurological disorders and found lowered levels in the schizophrenic group as compared with the control group. This finding supports the hypothesis of a NO system reduction in the brain of schizophrenic subjects.     

Nitric oxide as an activity marker in multiple sclerosis

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.     

Cerebrospinal fluid nitrite/nitrate correlated with oxyhemoglobin and outcome in patients with subarachnoid hemorrhage

The findings of various studies reporting temporal changes in CSF total nitrite/nitrate (NOx) levels after subarachnoid hemorrhage (SAH) vary considerably. The study group comprised 10 patients with SAH and 10 control subjects. Total nitrite/nitrate concentration was measured by a vanadium-based assay with the colorimetric Griess reaction. CSF oxyhemoglobin level was assessed by spectrophotometry. After an initial peak (22.6+/-10.1 microM) within first 24 h after SAH, CSF NOx decreased gradually during the period of observation. There was a significant correlation between CSF concentrations of NOx and OxyHb in the entire observation period (R=0.87, p<0.001). When the impact of bleeding into CSF was considered, patients with very good outcome [Glasgow Outcome Scale (GOS)=5] had significantly lower CSF NOx (11.1+/-1.3 microM) than those with worse outcome (GOS<5) (21.8+/-11.2 microM, p<0.01). In conclusion, this study demonstrates that after aneurysm rupture CSF NOx levels correlate with OxyHb. We suggest this as a novel interpretation of other variable findings in relation to NO metabolites in the central nervous system (CNS) post SAH, and hence it could usefully be incorporated into the planning of future studies, correlating NOx with clinical outcome.     

Serum and urine nitrate and nitrite are not reliable indicators of intrathecal nitric oxide production in acute brain injury

This study examined the correlation between nitric oxide (NO) metabolites in the three major body fluid compartments and assessed performance of newly described vanadium-based assay for simultaneous detection of nitrite and nitrate (NO(x)) in human samples. Vanadium reduces nitrate to nitrite, which can be measured after a colorimetric reaction with Griess reagents.Cisternal cerebro spinal fluid (CSF), serum and urine samples from 10 patients with acute brain injury (ABI) were compared to control subjects. Significantly higher CSF NO(x) levels were found in brain injury patients compared to control patients (19.7+/-13.7 vs. 6.5+/-2.3 microM; p=0.01), which persisted for 10-day period of observation. The serum and urine levels of NO(x) on admission were not statistically different (42.8+/-28.2 microM; 584.1+/-337.8 micromol/g Cr, respectively) from controls (36.8+/-14.8 microM; 819.7+/-356.0 micromol/g Cr), but tended to decrease during the disease course reaching the lowest level on day 6 (serum: 19.3+/-8.4 microM, urine: 300.4+/-111.9 micromol/g Cr). CSF levels of NO(x) correlated moderately with those in serum (p=0.001, R=0.5). Serum NO(x) concentrations correlated weakly with urine levels (p=0.04, R=0.3). There was no significant correlation between CSF NO(x) and urine NO(x) levels.In conclusion, patients suffering brain injury had increased NO(x) concentrations in CSF, which remained independent from other body fluid compartments. Serum and urinary NO(x) levels cannot be used as a reliable index to assess intrathecal NO production.     

Nitrite and malondialdehyde content in cerebrospinal fluid of patients with Parkinson's disease

Evidence from clinical and experimental studies supports the hypothesis of free radical-mediated damage of dopaminergic neurons in the pathology of Parkin's disease (PD). The present study was undertaken to evaluate the role of nitric oxide and oxidative stress in PD. Estimation of the stable metabolites of nitric oxide (NO, nitrite, nitrate) and malondialdehyde (MDA), an acceptable marker of lipid peroxidation, can provide indirect evidence of involvement of free radicals. Nitrite and malondialdehyde (MDA) levels were estimated in the lumbar cerebrospinal fluid (CSF) of 20 controls and 21 patients with PD. Nitrite and MDA content was not significantly altered in the CSF of PD patients as compared to the controls. Nitrite and MDA levels in CSF of PD patients exhibited no correlation with age, duration of disease, and severity of illness (measured by the Unified Parkinson's Disease Rating Score). There was no correlation between the CSF nitrite and MDA level. Findings of the present study do not provide evidence for the involvement of nitric oxide and oxidative stress in PD.     

Endothelin and nitric oxide levels in cerebrospinal fluid of patients with multiple sclerosis

In order to investigate the potential role of endothelins (ETs) and nitric oxide (NO) in the pathogenesis of multiple sclerosis (MS) we evaluated the levels of these vasoactive mediators in cerebrospinal fluid (CSF) of relapsing remitting MS patients and in a group of subjects with other neurological diseases (OND) and in a control group of subjects without neurological disease. Eighty patients affected from clinically diagnosed MS were selected, 44 of them were studied during an acute clinical attack and 36 in a stable phase. The OND group included 21 subjects affected by degenerative non inflammatory (n=9) and inflammatory (n=12) neurological disease while the control group included 22 subjects with cancer of the prostate (n=11) and with bladder disease (n=11). ET levels were significantly increased in CSF of relapsing remitting MS patients with an acute clinical attack in comparison with those in a stable phase, the OND group and the control group. Moreover significant differences were observed among the four groups with regard to the NO levels: MS patients in a stable and acute phase like OND group have high levels of NO compared to the control group. Since the blood-brain barrier index values did not differ significantly between the three groups, the data of this study suggest an important role for NO and ET in cerebral microcirculation in MS patients.     

NITRITE AND MALONDIALDEHYDE CONTENT IN CEREBROSPINAL FLUID OF PATIENTS WITH PARKINSON’S DISEASE

Evidence from clinical and experimental studies supports the hypothesis of free radical–mediated damage of dopaminergic neurons in the pathology of Parkin's disease (PD). The present study was undertaken to evaluate the role of nitric oxide and oxidative stress in PD. Estimation of the stable metabolites of nitric oxide (NO, nitrite, nitrate) and malondialdehyde (MDA), an acceptable marker of lipid peroxidation, can provide indirect evidence of involvement of free radicals. Nitrite and malondialdehyde (MDA) levels were estimated in the lumbar cerebrospinal fluid (CSF) of 20 controls and 21 patients with PD. Nitrite and MDA content was not significantly altered in the CSF of PD patients as compared to the controls. Nitrite and MDA levels in CSF of PD patients exhibited no correlation with age, duration of disease, and severity of illness (measured by the Unified Parkinson's Disease Rating Score). There was no correlation between the CSF nitrite and MDA level. Findings of the present study do not provide evidence for the involvement of nitric oxide and oxidative stress in PD.     

Nitric oxide metabolites and interleukin-6 in cerebrospinal fluid from multiple sclerosis patients

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.     

Amine metabolites in the cerbrospinal fluid in Huntington''s chorea

The amine metabolites HVA and 5-HIAA in the lumbar CSF of 15 patients with Huntington's chorea were determined. A negative correlation was found between the severity of symptoms and the CSF HVA, but not 5-HIAA levels. The mean HVA concentration was lower than that of a group of patients with miscellaneous neurological disorders, similar to that of a group with miscellaneous psychiatric disorders and higher than that of a group with Parkinson's disease. The mean 5-HIAA concentration was similar to that of the neurological group and higher than those of the groups with psychiatric disorders or Parkinson's disease. CSF HVA and 5-HIAA concentrations of a single patient with severe akinetic rigid Huntington's chorea were similar to those found in Parkinson's disease. The findings are discussed in relation to previous neuropathological observations and to reported effects of drugs on the choreic symptoms.     

Nitrite,nitrate and cGMP in the cerebrospinal fluid in degenerative neurologic diseases

Summary To investigate whether nitric oxide (NO) plays a role in degenerative neurologic disease (DND), we measured nitrite, nitrate and cyclic GMP in cerebrospinal fluid (CSF) samples from patients with Parkinson's disease (PD), spinocerebellar ataxia (SCA) and amyotrophic lateral sclerosis (ALS). We found no significant change in CSF nitrite, nitrate or cyclic GMP in patients with any DND compared with control values. These results suggest that NO production is preserved in PD, SCA and ALS.     

Nitric oxide-related brain damage in acute ischemic stroke

BACKGROUND AND PURPOSE: The neurotoxic and neuroprotective role of nitric oxide (NO) in experimental cerebral ischemia has generated considerable debate. The aim of this study was to analyze the relationship between NO metabolite (NO-m) concentrations in cerebrospinal fluid (CSF) and clinical and neuroimaging parameters of brain injury in patients with acute ischemic stroke. METHODS: We studied 102 patients and 24 control subjects who were included in a larger previous study conducted to analyze risk factors of progressing stroke. NO generation was calculated by quantifying nitrates and nitrites with a colorimetric assay in CSF samples obtained within the first 24 hours from symptoms onset. Early neurological deterioration was defined as a fall of 1 or more points in Canadian Stroke Scale score between admission and 48 hours after inclusion. Infarct volume was measured on days 4 to 7 by cranial CT. RESULTS: Median NO-m concentrations [quartiles] were 2.1 [1.0, 4.5] micromol/mL in patients and 1.0 [1.0, 1.0] micromol/mL in control subjects (P<0.0001). In 45 patients with subsequent early neurological deterioration, NO-m levels in CSF were significantly higher than in those with stable stroke (4.0 [1.7, 7.8] versus in 1. 6 [1.0, 2.5] micromol/mL, P<0.0001). There was a moderate correlation between NO-m and infarct volume (coefficient 0.39, P<0. 001). NO-m concentrations >5.0 micromol/mL were significantly associated with early neurological worsening (OR 5.7, 95% CI 1.2 to 27.4; P=0.030) independent of other important factors related to progressing stroke, such as CSF glutamate levels. CONCLUSIONS: Our clinical findings suggest an important role of NO generation in acute ischemic stroke. Increased NO-m in CSF are associated with a greater brain injury and early neurological deterioration.