Acid Concentrations In Cerebrospinal Fluid Research Articles

Blood, urine and cerebrospinal fluid analysis in TH and AADC deficiency and the effect of treatment

BackgroundAromatic L-amino acid decarboxylase (AADC) deficiency and tyrosine hydroxylase (TH) deficiency are rare inherited disorders of monoamine neurotransmitter synthesis which are typically diagnosed using cerebrospinal fluid examination of monoamine neurotransmitter metabolites. Until now, it has not been systematically studied whether analysis of monamine neurotransmitter metabolites in blood or urine has diagnostic value as compared to cerebrospinal fluid examination, or whether monoamine neurotransmitter metabolites in these peripheral body fluids is useful to monitor treatment efficacy. MethodsAssessment, both by literature review and retrospective analysis of our local university hospital database, of monoamine neurotransmitter metabolites in urine, blood and cerebrospinal fluid, and serum prolactin levels, before and during treatment in patients with AADC and TH deficiency. ResultsIn AADC deficiency, 3-O-methyldopa in serum or dried blood spots was reported in 34 patients and found to be (strongly) increased in all, serotonin in serum was decreased in 7/7 patients. Serum prolactin was increased in 34/37 and normal in 3 untreated patients. In urine, dopamine was normal or increased in 21/24 patients, 5-hydroxyindoleacetic acid was decreased in 9/10 patients, and vanillactic acid was increased in 19/20 patients. No significant changes were seen in monoamine neurotransmitter metabolites after medical treatment, except for an increase of homovanillic acid in urine and cerebrospinal fluid after levodopa therapy, sometimes even in absence of a clinical response. After gene therapy, cerebrospinal fluid homovanillic acid increased in most patients (8/12), but 5-hydroxyindoleacetic acid remained unchanged in 9/12 patients.In TH deficiency, serum prolactin was increased in 12/14 and normal in the remaining untreated patients. Urinary dopamine was decreased in 2/8 patients and normal in 6. Homovanillic acid concentrations in cerebrospinal fluid increased upon levodopa treatment, even in the absence of a clear treatment response. ConclusionsThis study confirms that cerebrospinal fluid is the most informative body fluid to measure monoamine neurotransmitter metabolites when AADC or TH deficiency is suspected, and that routine follow-up of cerebrospinal fluid measurements to estimate treatment response is not needed. 3-O-methyldopa in dried blood spots and vanillactic acid in urine are promising peripheral biomarkers for diagnosis of AADC deficiency. However, in many patients with TH or AADC deficiency dopamine in urine is normal or increased thereby not reflecting the metabolic block. The value of serum prolactin for follow-up of AADC and TH deficiency should be further studied.

Chronic Flubendiamide Exposure Induces Oxidative Stress in Water Buffalo (<i>Bubalus bubalis</i>) Calves

Flubendiamide is a recently introduced, fast-acting insecticide with an excellent residual effect. In an unpublished study, it was reported not to cause any genotoxic, carcinogenic and neurotoxic effects in mammals. However, recent studies suggest that it is toxic for fish and Chinese tiger frog. Alterations in leukogram, erythrocytic indices and aspartic acid concentration in cerebrospinal fluid in water buffalo following its chronic exposure to flubendiamide have also been recorded in our laboratory.

Amino Acids in Cerebrospinal Fluid of Patients with Aneurysmal Subarachnoid Haemorrhage: An Observational Study.

The authors are aware of only one article investigating amino acid concentrations in cerebrospinal fluid (CSF) in patients with ruptured intracranial aneurysms, and this was published 31 years ago. Since then, both management of subarachnoid haemorrhage (SAH) and amino acid assay techniques have seen radical alterations, yet the pathophysiology of SAH remains unclear. To analyse the pattern of concentrations of amino acids and related compounds in patients with different outcomes following aneurysmal SAH. 49 CSF samples were collected from 23 patients on days 0-3, 5, and 10 post-SAH. Concentrations of 33 amino acids and related compounds were assayed by liquid chromatography tandem mass spectrometry in patients with good [Glasgow Outcome Scale (GOS) 1-3] and poor (GOS 4-5) outcome. Of the 33 compounds assayed, only hydroxyproline and 3-aminoisobutyric acid appeared not to increase significantly following SAH. In poor outcome patients, we found significantly higher concentrations of aspartic acid (p = 0.038), glutamic acid (p = 0.038), and seven other compounds on days 0-3 post-SAH; glutamic acid (p = 0.041) on day 5 post-SAH, and 2-aminoadipic acid (p = 0.033) on day 10 post-SAH. The most significant correlation with GOS at 3 months was found for aminoadipic acid on day 10 post-SAH (cc = -0.81). Aneurysmal rupture leads to a generalised increase of amino acids and related compounds in CSF. The patterns differ between good and poor outcome cases. Increased excitatory amino acids are strongly indicative of poor outcome.

Flubendiamide and Lead Exposure Alters Glial Fibrillary Acidic Protein and Aspartic Acid Concentrations in Cerebrospinal Fluid in Buffalo Calves

Changes in glial fibrillary acidic protein (GFAP) and aspartic acid (AA) concentrations in CSF following flubendiamide and lead exposure was studied. Male buffalo calves received daily oral dose of flubendiamide alone (n=4) @ 0.024mg/ kg/ day or lead acetate alone (n=4) @ 9.2 mg/ kg/ day or a combination of these two (n=4) for 90 days. Blood and CSF samples were collected and analyzed. GFAP in CSF did not alter in animals receiving flubendiamide alone. However, a significant increase in GFAP concentration in CSF was observed in animals receiving lead acetate. GFAP concentration showed a positive correlation (r = +0.545) with blood lead concentration in lead exposed animals, but no significant correlation was evident in animals exposed to both lead and flubendiamide. On the basis of results, it can be concluded that Aspartic acid concentration in CSF did not change significantly in lead treated animals, but increased significantly in flubendiamide treated animals. No significant alteration in AA level in CSF was observed in combined flubendiamide and lead treated animals. Flubendiamide exposure is associated with increase in AA level in CSF. Flubendiamide may have interactive effects with lead as evident from increase in GFAP and AA level in CSF after their combined exposure. This is the first report documenting alterations in GFAP and AA concentrations in CSF after flubendiamide exposure in mammals.

The l‐kynurenine–probenecid combination reduces neuropathic pain in rats

l-Kynurenine has antinociceptive effects in acute and inflammatory pain. This study determined the effect of l-kynurenine and its metabolite (kynurenic acid) on rats subjected to neuropathic pain. L5/L6 spinal nerve ligation induced tactile allodynia as measured with von Frey filaments using the up-down method. High-performance liquid chromatography and Western blot analysis determined kynurenic acid levels and expression of kynurenine amino transferase II (KAT II), respectively. l-Kynurenine (50-200 mg/kg, i.p.) or probenecid (100 mg/kg, i.p.) did not affect allodynia in neuropathic rats. In contrast, l-kynurenine (50-200 mg/kg, i.p.) in combination with probenecid (100 mg/kg, i.p.), an inhibitor of organic anion transport, reversed allodynia. Furthermore, intrathecal kynurenic acid (1-30 μg) reversed allodynia. Probenecid (100 mg/kg, i.p.) supplementation enhanced the maximal antiallodynic effect of intrathecal kynurenic acid (10 μg). Only the combined administration of l-kynurenine (200 mg/kg)/probenecid (100 mg/kg) increased the kynurenic acid concentration in cerebrospinal fluid. KAT II is expressed in dorsal root ganglia and dorsal spinal cord. KAT II expression was unchanged by the spinal nerve ligation or l-kynurenine/probenecid combination. The kynurenine/probenecid combination did not affect motor activity. l-Kynurenine produces its antiallodynic effect in the central nervous system through kynurenic acid. This effect may result from blockade of N-methyl-d-aspartate receptors. KAT II is expressed in dorsal root ganglion and dorsal spinal cord. Combined l-kynurenine and probenecid therapy has the potential to reduce neuropathic pain in humans.

Determination of dopamine, serotonin, and their metabolites in pediatric cerebrospinal fluid by isocratic high performance liquid chromatography coupled with electrochemical detection

A method to rapidly measure dopamine (DA), dihydroxyindolphenylacetic acid, homovanillic acid, serotonin (5-HT) and 5-hydroxyindoleacetic acid concentrations in cerebrospinal fluid (CSF) has not yet been reported. A rapid, sensitive, and specific HPLC method was therefore developed using electrochemical detection. CSF was mixed with an antioxidant solution prior to freezing to prevent neurotransmitter degradation. Separation of the five analytes was obtained on an ESA MD-150 x 3.2 mm column with a flow rate of 0.37 mL/min and an acetonitrile-aqueous (5 : 95, v/v) mobile phase with 75 mM monobasic sodium phosphate buffer, 0.5 mM EDTA, 0.81 mM sodium octylsulfonate and 5% tetrahydrofuran. The optimal electrical potential settings were: guard cell +325 mV, E1 -100 mV and E2 +300 mV. Within-day and between-day precisions were <10% for all analytes and accuracies ranged from 91.0 to 106.7%. DA, 5-HT, and their metabolites were stable in CSF with antioxidant solution at 4 degrees C for 8 h in the autoinjector. This method was used to measure neurotransmitters in CSF obtained from children enrolled on an institutional medulloblastoma treatment protocol.

Neuropeptide changes and neuroactive amino acids in CSF from humans and sheep with neuronal ceroid lipofuscinoses (NCLs, Batten disease)

Anomalies in neuropeptides and neuroactive amino acids have been postulated to play a role in neurodegeneration in a variety of diseases including the inherited neuronal ceroid lipofuscinoses (NCLs, Batten disease). These are often indicated by concentration changes in cerebrospinal fluid (CSF). Here we compare CSF neuropeptide concentrations in patients with the classical juvenile CLN3 form of NCL and the classical late infantile CLN2 form with neuropeptide and neuroactive amino acid concentrations in CSF from sheep with the late infantile variant CLN6 form. A marked disease related increase in CSF concentrations of neuron specific enolase and tau protein was noted in the juvenile CLN3 patients but this was not observed in an advanced CLN2 patient nor CLN6 affected sheep. No changes were noted in S-100b, GFAP or MBP in patients or of S-100b, GFAP or IGF-1 in affected sheep. There were no disease related changes in CSF concentrations of the neuroactive amino acids, aspartate, glutamate, serine, glutamine, glycine, taurine and GABA in these sheep. The changes observed in the CLN3 patients may be progressive markers of neurodegeneration, or of underlying metabolic changes perhaps associated with CLN3 specific changes in neuroactive amino acids, as have been postulated. The lack of changes in the CLN2 and CLN6 subjects indicate that these changes are not shared by the CLN2 or CLN6 forms and changes in CSF concentrations of these compounds are unreliable as biomarkers of neurodegeneration in the NCLs in general.

Amino acid concentrations in cerebrospinal fluid in children with acute lymphoblastic leukemia undergoing chemotherapy

Cerebrospinal fluid (CSF) amino acid concentrations were measured in 45 children with acute lymphoblastic leukemia (ALL). Central nervous system (CNS) disease was absent in 34 and present in 11 (Groups L and M, respectively) at diagnosis. Thirty-two otherwise healthy children with febrile convulsions were studied for comparison. Results from this study show that glutamine levels at Day 0 were significantly higher in patients than in controls. Patients in Group M had elevated glutamine levels compared to Group L. In comparison, at Day 14, concentrations of glutamine and asparagine decreased, while glutamic acid amounts increased significantly in Group L. Glutamine levels fell at Day 42 in Group M, which may have resulted from more intensive treatment. From this study we hypothesise that higher baseline glutamine levels are indicative of a greater risk for CNS leukemia. Large-scale prospective trials are required to confirm increased baseline CSF glutamine levels in ALL patients, to identify glutamine as a marker for CNS disease and to clarify underlying mechanisms regulating glutamine in ALL.

Decreased homovanillic acid concentrations in cerebrospinal fluid in children without a known defect in dopamine metabolism

Homovanillic acid (HVA) is a metabolite of dopamine, reflecting central dopamine metabolism, primarily situated in the striatum. Low HVA concentrations in the cerebrospinal fluid (CSF) may indicate metabolic deficiencies in the pathways of the biosynthesis or catabolism of dopamine. In this retrospective study, we investigated the clinical presentation of patients whose HVA concentration in the CSF had been determined routinely after spinal taps for a variety of clinical reasons. A decrease of HVA concentration in the CSF, due to a defect in the biosynthesis or reuptake of dopamine, is expected to cause extrapyramidal features. However, we found a remarkable variability in the clinical symptoms. Similarly, a decreased HVA concentration in the CSF failed to coincide with specific abnormalities at neuroimaging. In view of the diversity of the clinical presentation and in the absence of specific enzyme deficiencies, a decrease of HVA may be due to dysfunction of dopamine neurons, not resulting in specific extrapyramidal symptoms. Thus, with the exception of diseases associated with a specific enzyme deficiency in the metabolic pathways involving dopamine, a decrease of HVA concentration in the CSF is mainly a secondary or epiphenomenon in a variety of clinical conditions.

Neuron-specific enolase, nucleotides, nucleosides, purine bases, oxypurines and uric acid concentrations in cerebrospinal fluid of children with meningitis

To determine the effects of meningitis on cerebral energy metabolism, cerebrospinal fluid concentrations of adenosine monophosphate, inosine monophosphate, inosine, adenosine, guanosine, adenine, guanine, hypoxanthine, xanthine and urate were determined by high-performance liquid chromatography, and neuron-specific enolase by an enzyme immunoassay method, in 100 children with meningitis (45 bacterial, 46 viral and nine tuberculous), aged between 1 month and 13 years, and in 160 age-matched controls. Compared with controls, patients with bacterial meningitis showed high concentrations of hypoxanthine, xanthine and urate; patients with viral meningitis showed high concentrations of inosine, guanosine, xanthine, urate and neuron-specific enolase; and patients with tuberculous meningitis showed very high concentrations of inosine, xanthine and urate. Xanthine and urate concentrations were significantly higher in patients with tuberculous meningitis than in patients with viral or bacterial meningitis. These results suggest that in the acute stage of bacterial, viral and tuberculous meningitis, neuronal energy metabolism may be altered. The measurement of cerebrospinal xanthine and uric acid concentrations may be useful for the early diagnosis of a tuberculous origin.

Memantine, a noncompetitive NMDA receptor antagonist improves hyperammonemia-induced encephalopathy and acute hepatic encephalopathy in rats.

The aim of this study was to investigate the possible role of N-methyl-D-aspartate (NMDA)-receptor overactivity in two different experimental rat models of encephalopathy: subacute encephalopathy caused by severe hyperammonemia in portacaval-shunted rats (AI-PCS rats) and acute hepatic encephalopathy caused by complete liver ischemia (LIS rats). The effect of the noncompetitive NMDA-receptor antagonist memantine (intraperitoneal [i.p.] 10-20 mg/kg bw or intravenous [i.v.] 5 mg/kg bw) was studied on the severity of encephalopathy by assessment of clinical grading and electroencephalogram (EEG) spectral analysis, on plasma ammonia concentrations, amino acid concentrations in cerebrospinal fluid (CSF), intracranial pressure (ICP), and brain water content. Both rat models developed encephalopathy within 3 to 6 hours, associated with increased CSF glutamate and aspartate concentrations and increased ICP and brain water content. Memantine administration in AI-PCS and LIS rats resulted in a significant improvement in clinical grading and less slowing of EEG activity (P < .05), and smaller increases in CSF glutamate (P < .05) concentrations. Moreover, ICP and brain water content were significantly lower in memantine-treated AI-PCS rats than in untreated AI-PCS rats (P < .05). Memantine had no significant effect on ICP and brain water content in LIS rats, and on ammonia concentrations in both models. These results indicate that NMDA-receptor activation might be involved in the pathogenesis of hyperammonemia-induced encephalopathy and of acute hepatic encephalopathy caused by LIS.

Amino acid concentrations in cerebrospinal fluid of patients with multiple sclerosis.

As oligodendrocytes have binding sites for excitatory amino acids (glutamate, aspartate, serine, etc.), a role of these molecules in demyelinating disorders is possible. We measured the levels of amino acids in the cerebrospinal fluid (CSF) of patients with multiple sclerosis in comparison with CSF obtained by myelography from patients with lower back pain. There were no significant differences in the CSF concentrations of these amino acids between the two groups. Normal concentrations of excitotoxins do not exclude the role of these molecules in demyelinating disorders.

Cerebrospinal monoamine metabolites and amino acid content in patients with parkinsonian syndrome and rats lesioned with MPP+.

Monoamine metabolites and amino acid concentration in cerebrospinal fluid (CSF) of 33 untreated patients with parkinsonian syndrome, and 20 control patients without specific neurological symptoms have been compared with those obtained in cerebrospinal fluid of rats intrastriatally lesioned with 1-methyl-4-phenylpyridinium ion (MPP+) and sham operated animals. Homovanillic acid content was found to be significantly lower in patients with severe parkinsonism (motor score of UPDRS > 24), but not in patients with mild symptoms (motor score < or = 24). A correlation between the loss of striatal dopamine and the decrease in cerebrospinal homovanillic acid has been established in rats treated with MPP+. The extrapolation of these results to those obtained from human patients could be important in assessing the degree of striatal dopamine loss shown by humans with parkinsonian syndrome at the moment of clinical diagnosis. No significant differences were found between the other monoamine metabolites analyzed and free amino acid content in human and rat CSF.

Amino acid concentrations in cerebrospinal fluid and serum in Alzheimer's disease and vascular dementia.

Cerebrospinal fluid (CSF) and serum levels of 22 amino acids were studied in 13 patients with dementia of the Alzheimer type (DAT), 13 patients with vascular dementia (VD) and 15 age-matched controls. We found significantly reduced levels of glutamate in CSF samples from DAT patients compared to VD and control subjects, but CSF levels of aspartate were found to be significantly elevated in the two groups of dementia studied. Moreover, CSF concentrations of tyrosine, leucine and phenylalanine were significantly increased in VD patients in comparison with those in DAT patients and control subjects. Our results showed a wide increase in CSF/serum amino acid ratios in DAT and VD groups compared to controls. However, no differences were found in CSF/serum ratios between dementia groups. These changes show evidence for a possible disorder of amino acid metabolism with different patterns in these two dementia types.

Kynurenic acid concentrations are reduced in Huntington's disease cerebral cortex

Huntington's disease (HD) is characterized by gradually evolving selective neuronal death. Several lines of evidence suggest that an excitotoxic mechanism may play a role. Tryptophan metabolism leads to production of quinolinic acid, an N- methyl- d-aspartate (NMDA) receptor agonist, and to kynurenic acid, an antagonist at these same receptfors. We recently found increased kynurenine to kynurenic acid ratios in HD postmortem putamen and decreased kynurenic acid concentrations in cerebrospinal fluid, consistent with decreased formation of kynurenic acid in HD brain. In the present study we used HPLC with 16 sensor coulometric electrochemical detection to measure kynurenic acid and 18 other electrochemically active compounds in 6 cortical regions, caudate and cerebellum from controls, HD, Alzheimer's disease (AD), and Parkinson's disease (PD) patients. Significant reductions in kynurenic acid concentrations were found in 5 of 6 cortical regions examined. Smaller reductions of kynurenic acid in the caudate, cerebellum and frontal pole were not significant. No significant reductions were found in the AD and PD patients. Both uric acid and glutathionine were significantly reduced in several regions of HD cerebral cortex, which could signify abnormal energy metabolism in HD. Since kynurenic acid is an antagonist of excitatory amino acid receptors, a deficiency could contribute to the pathogenesis of neuronal degeneration in HD.

Amino acid concentrations in cerebrospinal fluid and plasma in Alzheimer's disease and healthy control subjects

Cerebrospinal fluid (CSF) and plasma levels of 18 amino acids were studied in 22 subjects with dementia of the Alzheimer type (DAT) and in 11 healthy volunteers with no clinical or family history of dementia. Significant decreases of plasma taurine and glutamate were seen in the DAT cases compared with the controls. The CSF concentrations of glycine, leucine and valine were also significantly reduced in the DAT cases. Furthermore, in the DAT cases significant decreases were observed in the ratio between CSF and plasma (CSF/P) levels for alanine, glutamine, glycine, phenylalanine and valine, when compared with controls. In the DAT group there were significant correlations between behaviour and CSF glutamine; memory and cognitive functions and CSF valine; copying ability and CSF glutamate. CSF/P ratios of glutamine and glutamate correlated with behaviour and copying performances, respectively. The results of this study provide further evidence for a disruption of amino acid metabolism in DAT.

Amino acid concentrations in cerebrospinal fluid in presenile and senile dementia of Alzheimer type and multi-infarct dementia

Free amino acid levels were measured in cerebrospinal fluid (CSF) from demented patients (D n = 30) suffering from presenile and senile dementia of Alzheimer type (PDAT, n = 7; SDAT, n = 9), multi-infarct dementia (MID, n = 14) and a reference sample group consisting of young neurotic patients (R, n = 16). Comparing the amino acid levels in the dementia subgroups, significantly higher alanine, methionine, phenylalanine and tyrosine levels were found both in MID and SDAT vs. PDAT. No difference was seen between SDAT and MID. Compared to the reference sample group, higher glycine levels were found in each dementia subgroup; higher alanine, methionine and ornithine levels in MID, and SDAT; and higher phenylalanine levels in MID. In PDAT the level of tyrosine was lower. Coefficients of correlation were calculated between amino acid levels and age, and the findings in the reference sample groups were divergent from those observed in dementia. The differences observed are discussed in terms of amino acid, carbohydrate and neurotransmitter metabolism.

A twin study of amino acid concentrations in cerebrospinal fluid

The concentrations of amino acids in the cerebrospinal fluid (CSF) were measured in pairs of healthy mono- and dizygotic twins. Intraclass correlations were calculated. Genetic and cultural heritabilities were estimated using a path analytical model. CSF levels of glycine, tyrosine and arginine were shown to be influenced by genetic factors. Genetic variation was also shown for serine, alpha-aminobutyrate and leucine. The results were compared with results from a genetic analysis of the amino acids in serum.

Eicosanoids in human ventricular cerebrospinal fluid following severe brain injury

Recent evidence has shown that a variety of prostaglandins and leukotrienes can be produced in brain tissue after injury in animals. It has also been speculated that increases in brain prostaglandins occur in humans following injury. Ventricular cerebrospinal fluid (CSF) samples have been obtained from children with static lesions (controls) as well as children with acute brain injury and eicosanoids measured by immunologic techniques. Metabolites of prostacyclin (6-keto-PGF 1a) and thromboxane A 2 (thromboxane B 2) were the major eicosanoids found in CSF, and levels of these compounds were increased 3–10 times in acutely injured patients. Prostaglandin E 2 was also found in lower amounts, although in one case its level was very high. Prostaglandin D 2 was also present, but in low amounts. No leukotrienes were found in CSF samples that were purified by HPLC prior to immunoassay. Elevated levels of hydroxyeicosatetraenoic acids (HETEs) were observed in those samples stored frozen, but these metabolites were most probably due to autooxidation of archidonic acid in CSF. Arachidonic acid concentration in CSF was typically found to be in the range of 10–200 ng/ml, but was found to be 5–10 fold higher in one severely injured patient. Thus, elevated free arachidonic acid and various oxygenated metabolites were observed in CSF following brain injury.

Amino acid transport across the human blood-CSF barrier: An evaluation graph for amino acid concentrations in cerebrospinal fluid

The correlation of cerebrospinal fluid (CSF)/serum concentration quotients was used as a method for identification of amino acids which are transported by a common carrier system across the blood-CSF barrier. Isoleucine, leucine, valine, phenylalanine, tyrosine and lysine were found to compete for the same carrier system. This group of amino acids in man was found to be different from the system described as a neutral amino acid carrier at the blood-brain barrier in rats. In man, methionine and tryptophan do not compete with the other neutral amino acids for the same carrier system. In contrast, lysine as a basic amino acid is found to be correlated with the same transport system as the five neutral amino acids. A graph for the evaluation of pathological amino acid concentrations in CSF is presented. Patients with a blood-CSF barrier dysfunction for proteins showed partly normal, partly increased, CSF/serum concentration quotients for the amino acids. Hydroxyproline could be identified as a constituent of the amino acid pool in CSF. For proline and hydroxyproline a special control system has to be suggested because of their smaller biological variance in CSF than in blood. Contrary to the other amino acids proline and hydroxyproline have a smaller biological variation in CSF than in serum.