[Endorphins and neurotensin in Huntington chorea]

Concentration of alpha-endorphin, beta-endorphin, gamma-endorphin and neurotensin in blood and beta-endorphin in cerebrospinal fluid of 48 patients with various forms of Huntington's disease was measured. Two modifications of immunoassay were used. The level of all neuropeptides studied was significantly decreased. Patients with a kinetiko-rigid form of the disease showed a two-fold lowering in beta-endorphin levels in cerebrospinal fluid in comparison with patients with the classic form. The relationships between these findings and clinical-biochemical characteristics of Huntington's disease are discussed.

Decreased plasma alanine and isoleucine in Huntington's disease

Amino acid concentrations in plasma of patients with Huntington's disease (HD) were determined in 16 patients and 21 age- and sex-matched healthy controls. Alanine and isoleucine were significantly decreased in HD plasma whereas arginine, histidine, leucine, lysine, ornithine, proline, serine, threonine, tyrosine, and valine showed no significant changes. Our findings confirm the decreases of alanine and isoleucine that were described in plasma and cerebrospinal fluid by other investigators. A possible defect in cellular uptake or metabolism of neutral amino acids seems to be a consistent feature of HD.

Cerebrospinal fluid homovanillic acid is reduced in untreated Huntington's disease

We measured homovanillic acid (HVA), 5-hydroxy indole acetic acid (5-HIAA), and tryptophan (TP) in cerebrospinal fluid (CSF) of 20 neuroleptic-free patients with Huntington's disease (HD), and compared mean values with those from four control groups including 15 normal individuals, 38 patients with dystonia, 23 untreated patients with Parkinson's disease, and 61 patients with other neurological diseases (ONDs). The mean levels of HVA in the CSF of patients with HD were reduced compared with those from normal controls (p < 0.001), dystonic patients (p < 0.005), individuals with ONDs (p < 0.0001), and even from untreated parkinsonian patients (p < 0.05). 5-HIAA and TP levels in the CSF of patients with HD were not significantly different from those in the CSF of control patients. Our data suggest a reduced dopamine neurotransmission in HD and may account for the bradykinesia observed in our patients.

Elevated levels of the endosomal-lysosomal proteinase cathepsin D in cerebrospinal fluid in Alzheimer disease

Lysosomal hydrolases are normally intracellular enzymes but are abundant extracellularly within senile plaques in Alzheimer disease and in other conditions where beta-amyloid accumulates. To examine whether acid hydrolases released from abnormal hydrolase-laden neurons are detectable in CSF, we measured levels of the major aspartic proteinase of lysosomes, cathepsin D (Cat D), in ventricular CSF collected after death from 30 patients with Alzheimer disease, 14 patients with Huntington disease, and seven patients with other neurodegenerative diseases. The levels of Cat D-immunoreactive protein, expressed as micrograms per milliliter of protein, determined by western blot immunoassay using a polyclonal antiserum against human brain Cat D, were more than fourfold higher in the Alzheimer patients than in the other patient groups (p < 0.0005). Cat D activity, assayed separately against [14C]methemoglobin at pH 3.2, was also significantly elevated but less than Cat D content. The lower specific activity of Cat D in Alzheimer CSF therefore indicated that the abnormally accumulated Cat D included a high proportion of inactive enzyme. These results indicate that abnormal Cat D release from affected neurons into the extracellular space is an active, ongoing process in Alzheimer brain. In addition, the levels of this enzyme and possibly other lysosomal hydrolases in CSF may prove to be useful biological markers of Alzheimer disease.

Cerebrospinal fluid nitrite/nitrate levels in neurologic diseases

Nitric oxide has been proposed to mediate cytotoxic effects in inflammatory diseases. To investigate the possibility that overproduction of nitric oxide might play a role in the neuropathology of inflammatory and noninflammatory neurological diseases, we compared levels of the markers of nitric oxide, nitrite plus nitrate, in the CSF of controls with those in patients with various neurologic diseases, including Huntington's and Alzheimer's disease, amyotrophic lateral sclerosis, and HIV infection. We found that there were no significant increases in the CSF levels of these nitric oxide metabolites, even in patients infected with HIV or in monkeys infected with poliovirus, both of which have significantly elevated levels of the neurotoxin quinolinic acid and the marker of macrophage activation, neopterin. However, CSF quinolinic acid, neopterin, and nitrite/nitrate levels were significantly increased in a small group of patients with bacterial and viral meningitis.

Analysis of glial fibrillary acidic protein in the cerebrospinal fluid of children investigated for encephalopathy

The clinical application of a newly developed highly sensitive ELISA method (20) to assay glial fibrillary acidic protein (GFAP) in the cerebrospinal fluid (CSF) was investigated in children and adolescents with neurological disorders. GFAP analysis was explored as a tool to differentiate disorders with ongoing astrocytosis. A consecutive series of 34 subjects, 17 boys and 17 girls, with nonprogressive and progressive neurological encephalopathies was compared to 10 healthy controls. The mean CSF GFAP concentration of the controls was 60.6 +/- 54 ng/l (SD). The group of 24 subjects (12 boys and 12 girls) with progressive neurologic disorders had higher mean CSF GFAP levels than the group of 10 subjects (5 boys and 5 girls) with non-progressive disorders, 222.6 +/- 186 and 127.5 +/- 86 ng/l, respectively. The progressive encephalopathies differed significantly from controls (p < 0.01) while the non-progressive did not. The mean GFAP concentration of the epilepsy cases (n = 18) and non-epilepsy cases (n = 16) was 212.9 +/- 196 and 174.0 +/- 132 ng/l, respectively. The epilepsy cases differed significantly from controls which could be explained by the dominance of progressive cases (15 out of 18).(ABSTRACT TRUNCATED AT 250 WORDS)

CSF and serum metabolic profile of patients with Huntington's chorea: a study by high resolution proton NMR spectroscopy and HPLC

We studied both cerebrospinal fluid (CSF) and serum of 11 patients suffering from Huntington's disease (HD) and 12 control subjects by combining high resolution proton NMR spectroscopy and HPLC. NMR spectroscopy analysis of the CSF shows a significant increase (60%) in pyruvate concentration in HD patients. No unexpected molecules were detected. Glutamate, glutamine, aspartate, proline and GABA levels were found unchanged in the CSF of HD patients, using HPLC analysis. Conversely, a significant increase (30%) in the CSF level of glycine was detected. These observations are in agreement with the metabolic hypothesis of HD physiopathogenesis. In addition, the protocol combining NMR spectroscopy and HPLC provides a straightforward evaluation of brain metabolic status and blood-brain-barrier function.

Reduced regional cerebral blood flow in Huntington's disease studied by SPECT

Regional cerebral blood flow (rCBF) was studied in 18 patients with Huntington's disease (HD) and 19 age- and sex-matched controls with high resolution single photon emission computerised tomography (SPECT), using Tc-99m-HMPAO. Significant reductions in tracer uptake were found in the caudate and lentiform nuclei (20 and 8%) and in the cerebral cortex, especially in the frontal and parietal areas (11-13%). No significant reductions were found in the thalamus, mesial temporal cortex, and occipital cortex. Fourteen patients had neuropsychological testing. Relationship between rCBF and cognitive function was tested by regression analysis. A linear relationship was found between test scores of Wisconsin Card Sorting Test, Picture Arrangement Test and blood flow in the caudate nucleus. Other tests of cognitive function (Block Design Test, Face and Word Recognition Test, Street Fragmented Pictures Test, and Similarities Test) correlated better with flow in the cortical regions believed to be involved in solving those particular tests. These findings indicate, that blood flow is reduced in both cortical and subcortical structures in symptomatic HD, and that both reductions in cortical and subcortical blood flow may be related to cognitive function in HD.

Putamen volume reduction on magnetic resonance imaging exceeds caudate changes in mild Huntington's disease

The characteristic pathological features of Huntington's disease (HD) are neostriatal atrophy and neuronal loss. Although neuroradiological studies often show caudate atrophy in patients with moderate HD, frequently no caudate atrophy is found early in the illness. There have been no quantitative reports to date on in vivo putamen volume measures in mild HD, although the structure is known to be neuropathologically involved in the illness. We measured volumes of caudate nucleus and putamen and bicaudate ratios (BCR) from magnetic resonance images, blind to diagnosis, in 15 patients with mild HD and 19 age- and sex-matched control subjects using a computerized image analysis system. The region showing greatest atrophy was the putamen, which was reduced 50.1% in mean volume in HD patients compared with control subjects (p less than 0.000001). In contrast, caudate volume was reduced 27.7% (p = 0.004). BCR was increased 28.5% in HD patients (p = 0.0002). Discriminant function analysis was 94% effective in identifying the diagnostic group based on putamen volume alone, whereas caudate measures had considerable overlap. Correction of putamen volume for head size led to 100% separation by group. Putamen measures and BCR correlated with neurological examination scores but caudate volume did not. Volumetric measurement of putamen is a more sensitive indicator of brain abnormalities in mild HD than measures of caudate atrophy.

Increased cerebrospinal fluid dopamine and 3,4-dihydroxyphenylacetic acid levels in Huntington's disease: evidence for an overactive dopaminergic brain transmission

Levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), noradrenaline (NA), 3-methoxy-4-hydroxyphenylglycol (MHPG), and 5-hydroxyindoleacetic acid (5-HIAA) in the CSF of patients with Huntington's disease (HD) were measured by HPLC. CSF DA, DOPAC, and MHPG levels were found to be increased in HD patients. Levels of HVA, 5-HIAA, and NA in the CSF of HD patients did not differ from those of controls. Changes in CSF DA and DOPAC levels were consistent with previous findings of increased DA tissue content in some brain areas of patients with HD. These results suggest that CSF DOPAC levels could be a more reliable index of overactive dopaminergic brain systems in HD than CSF HVA levels.

Regional brain and cerebrospinal fluid quinolinic acid concentrations in Huntington's disease

Many of the characteristics neuroanatomical and neurochemical features of Huntington's disease (HD) are produced in experimental animals by an intrastriatal injection of the endogenous N-methyl-D-aspartate receptor agonist quinolinic acid (QUIN). Conceivably, a chronic over-production of QUIN in brain could be involved in the pathogenesis of HD. To investigate this hypothesis, concentrations of QUIN were measured both in cerebrospinal fluid (CSF) and postmortem tissue from patients with HD and neurologically normal age-matched controls. CSF QUIN concentrations were slightly lower in patients with HD, however the changes were not significant. Mean concentrations of QUIN tended to be lower in HD putamen, dentate nucleus and several cortical regions, although significant reductions were found only in Brodmann areas 17, 20 and 28. The mechanisms responsible for these small reductions in brain QUIN concentrations remain to be determined. These results do not support the hypothesis that a chronic increase of QUIN production is responsible for neurodengeneration in HD.

Histamine metabolites and pros-methylimidazoleacetic acid in human cerebrospinal fluid

In cerebrospinal fluid, levels of the histamine metabolites, tele-methylhistamine and tele-methylimidazole-acetic acid, were higher in elderly than in young people, and women had higher levels than men. Therefore, age and gender should be considered in studies of histamine metabolites as exemplified by their measurements in cerebrospinal fluid of patients with Huntington's disease. Levels of pros-methylimidazoleacetic acid, an isomer of tele-methylimidazoleacetic acid and not a metabolite of histamine, were higher in cerebrospinal fluid of men than of women. Levels of pros-methylimidazoleacetic acid in cerebrospinal fluid were highly positively correlated with the severity of Parkinson's disease in a group of non-medicated, mildly to moderately affected patients.

Cerebrospinal fluid acetylcholinesterase and choline measurements in Huntington's disease

The caudate nucleus has the highest acetylcholinesterase (AChE) activity in the brain and it has been shown that autopsied brain tissue of patients with Huntington's disease (HD) have reduced levels of acetylcholine. Because of these findings, the cholinergic function in HD was studied by measuring cerebrospinal fluid (CSF) choline levels and AChE activity during a randomized, double-blind, cross-over, placebo-controlled clinical trial of isoniazid. While mean choline levels adjusted for age were lower compared with controls (P = 0.0007), AChE activity did not differ between HD patients and normal controls. Treatment with isoniazid had no significant effect on CSF choline levels or CSF AChE activity. CSF AChE activity showed a statistically significant increase with advancing age. The reduced level of choline in CSF of HD patients may reflect either a defect in choline transport into the brain or a decrease of choline-phospholipid output from the brain.

Cerebrospinal fluid levels of diazepam-binding inhibitor in neurodegenerative disorders with dementia

We investigated CSF levels of diazepam-binding inhibitor (DBI), a recently discovered neuropeptide that allosterically modulates GABAergic transmission, in various neurodegenerative disorders with dementia (28 patients with Parkinson's disease, 10 with Alzheimer's disease, 7 with Huntington's chorea). We applied a battery of neuropsychological tests to determine the degree of dementia and to exclude the presence of mood alterations. CSF DBI levels were elevated in parkinsonian subjects with dementia and in patients with Alzheimer's disease, but decreased in Huntington's chorea patients. We hypothesize that modifications of CSF DBI levels may be related to a functional or structural alteration of the GABAergic system.

What excitotoxin kills striatal neurons in Huntington's disease? Clues from neurochemical studies

Amino acid analyses of both caudate nucleus and putamen obtained at autopsy from patients dying with Huntington's disease (HD), and from control subjects, showed significantly decreased mean glutamate contents in the HD patients. In addition, the mean glutamate concentration was significantly increased in the CSF of living HD patients as compared with controls. Neurochemical studies also showed that neither aspartic acid, proline, 5-oxoproline, nor homocysteic acid is likely to act as a causative excitotoxin in HD. Excessive striatal glycine content, or deficient glutathione content, is unlikely to contribute to the effects of a causative excitotoxin in HD. We suggest that glutamic acid may be the proximate causative neurotoxin in the striatum in HD, as a result of an unexplained failure in the reuptake mechanism for glutamate released there as an excitatory neurotransmitter.

Decrease in a proenkephalin peptide in cerebrospinal fluid in Huntington's disease and progressive supranuclear palsy

The cerebrospinal fluid (CSF) content of Met5-enkephalin-Arg-Gly-Leu immunoreactivity was found to be significantly decreased in patients with Huntington's disease and progressive supranuclear palsy. This peptide is derived from the proenkephalin precursor protein and normally is found in high concentrations in the basal ganglia. The decrease in CSF from Huntington's disease patients likely reflects the loss of proenkephalin-containing neurons seen in postmortem analyses of basal ganglia tissue. The decrease in progressive supranuclear palsy, a disease in which dopamine neurons degenerate but enkephalin levels in the basal ganglia are reportedly not decreased, may reflect a functional decline in enkephalinergic neuronal activity secondary to a striatal cholinergic deficit. The results suggest that a substantial portion of the CSF Met5-enkephalin-Arg-Gly-Leu immunoreactivity is derived from the basal ganglia and that CSF levels of this peptide can serve as an index of functional or anatomical integrity of proenkephalin synthesizing neurons in the basal ganglia.

Isoniazid-induced alteration of CSF neurotransmitter amino acids in Huntington's disease

During a randomized, double-blind, crossover, placebo-controlled clinical trial of isoniazid (plus pyridoxine) in Huntington's disease (HD), amino acids and related amino compounds were measured in both cerebrospinal fluid (CSF) and plasma utilizing a newly developed high-performance liquid chromatography ion-exchange/fluorometric assay method. Results showed that isoniazid (plus pyridoxine) significantly elevated the mean (+/- S.E.M.) levels of gamma-aminobutyric acid, aspartate, asparagine, homocarnosine, ornithine, histidine, alpha-aminobutyric acid, isoleucine, leucine and alanine in CSF and the levels of beta-alanine in both CSF and plasma. These alterations can be traced to inhibition of decarboxylation and transamination reactions requiring the cofactor pyridoxal phosphate and may be related to the observed equivocal clinical response in the HD patients. The differential influence of isoniazid on plasma and CSF amino acid profiles suggests that alterations of CNS amino acid metabolism may be reflected in CSF, and that isoniazid-induced alterations of amino acid metabolism in the CNS differ from those in the periphery.

Free and conjugated CSF and plasma GABA in Huntington's chorea

Free and conjugated GABA concentrations were measured in CSF and plasma from 28 patients with manifest Huntington's chorea (HC) and 30 age- and sex-matched controls. GABA was determined by ion-exchange chromatography with fluorimetric detection (IE/F). Free and conjugated CSF GABA was significantly decreased in prolonged HC with advanced disease states and was suggested practicable as an additional diagnostic tool. However, in younger patients (less than 40 yrs) with a short period of HC (less than 2 yrs) an overlap with the age-matched normal range indicated GABA measurement inadequate to early diagnosis nor predictive for offspring at risk. An age-dependent decrease of conjugated CSF GABA was observed in patients and controls. The more pronounced decrease in patients might reflect the neurodegenerative feature of HC.

CSF somatostatin-like immunoreactivity in dementia

Concentrations of somatostatin-like immunoreactivity (SLI) in CSF were reduced in Alzheimer's disease (AD) and multi-infarct dementia (p less than 0.01), but not in normal-pressure hydrocephalus, Parkinson's disease, and Huntington's disease. This suggests that reduced SLI content in AD cerebral cortex is reflected in CSF. Chromatographic characterization of CSF SLI showed no differences between AD and controls. Concentrations of SLI in AD patients overlapped those in both normal subjects and patients with multi-infarct dementia, so that changes in CSF SLI have no diagnostic specificity.

Neurochemistry of dopamine in Huntington's dementia and normal aging

We measured the dopamine metabolite homovanillic acid (HVA) in cerebrospinal fluid (CSF) before and after probenecid administration in normal controls and in patients with Huntington's disease. Baseline CSF HVA concentrations correlated positively with age in normal control subjects. Baseline CSF HVA concentrations were reduced in patients with Huntington's disease, and the degree of this reduction correlated with the severity of dementia and with the duration of disease. These results suggest that changes in the metabolism of dopamine by dopaminergic neurons may be associated with the dementia of Huntington's disease as well as with normal aging. These changes in dopaminergic functioning are apparently different in Huntington's disease than in normal aging and can be detected by measuring CSF HVA concentration.

Free and conjugated GABA in human cerebrospinal fluid: effect of degenerative neurologic diseases and isoniazid

gamma-Aminobutyric acid (GABA) was measured in CSF as such and following acid hydrolysis by the ion-exchange/fluorometric method. The conjugated GABA level was obtained by subtracting the free GABA level from the total GABA level. Results showed that at room temperature, while the free GABA level increased, the level of conjugated GABA decreased in a linear fashion during the first 24 h (r = -0.974; P less than 0.001). Aging and CSF conjugated GABA levels were inversely correlated (r = -0.613; P less than 0.05). Unlike free GABA levels, the levels of conjugated GABA were not altered in Huntington's disease, Parkinson's disease, cerebellar ataxias, dementias, epilepsy and multiple sclerosis compared to controls. In patients with Huntington's disease, on administration of isoniazid at 900 mg/day, along with pyridoxine at 100 mg/day, a 4-fold increase of both free (P less than 0.005) and conjugated GABA (P less than 0.0025) was seen. The results indicate that while total GABAergic peptides are not altered in several of the neurologic diseases studied, drugs such as isoniazid and/or pyridoxine can significantly elevate both free and conjugated GABA levels in human CSF.

Further characterization of in vitro conditions appropriate for GABA determination in human CSF: impact of acid deproteinization and freeze/thaw

Recently established standardized protocols for collection, handling, and storage of CSF for measurement of gamma-aminobutyric acid (GABA) have proven valuable in the characterization of various CNS disorders. In response to two recent reports which may have an impact on certain widely used protocols, we have, using the confirmed ion-exchange/fluorometric procedure, systematically evaluated the effects of deproteinization with various concentrations of sulfosalicylic acid (SSA) ranging from 0 to 10% (100 mg/ml), as well as the effects of freeze/thaw (F/T) on CSF GABA levels. Results of F/T studies documented that levels are stable to freezing and thawing. Acid deproteinization studies revealed the presence of an equilibrium between strictly free GABA, demonstrable only in acid-free CSF, and a very loosely bound form of GABA, fully demonstrable only in CSF deproteinized with concentrations of SSA above 1% (10 mg/ml). The relationship between GABA concentrations in undeproteinized and acid-deproteinized CSF revealed a highly significant (p less than .001) correlation, suggesting that alterations of central GABAergic activity would be reflected by either the level of strictly free GABA or free plus loosely bound GABA. This hypothesis was upheld in studies of patients with Parkinson's disease (PD) and Huntington's disease (HD), two neurologic disorders in which dysfunctions of the GABA system have been implicated. Results indicated that CSF GABA levels are significantly reduced in both PD and HD patients compared with neurologically normal controls, whether the measurement is of free GABA or free plus loosely bound GABA. Thus, we conclude that the level of strictly free GABA is stable to freezing and thawing and can only be accurately determined in nonacidified CSF; however, existing protocols employing deproteinization in 5% SSA yield data that provide an equally good reflection of central GABAergic transmission.

Decreased level of beta-endorphin-like immunoreactivity in cerebrospinal fluid of patients with senile dementia of Alzheimer type

beta-Endorphin-like immunoreactivity in cerebrospinal fluid(CSF) was observed to decrease in patients with Huntington's disease and dementia due to brain vascular disease. The greatest decrease was seen in patients with presenile and senile dementia of Alzheimer type(SDAT). The immunoreactivity significantly correlated with psychological functions when examined using a dementia rating scale (r=0.51, p less than 0.01, for all dementia, r=0.65, p less than 0.02, for only SDAT). These results suggest that a B-endorphin-like substance may be related in the pathophysiology of dementia.

Further studies of the cytopathic effect in tissue cultures inoculated with CSF from patients with schizophrenia and other nervous system diseases

Tissue cultures were inoculated with CSF from patients with schizophrenia and some other psychiatric and neurological illnesses. The CPE was readily seen in all 13 strains of human skin fibroblasts examined but could not be serially passaged. The results of retesting many specimens, either by the same worker or under full double blind conditions, usually agreed and thus indicate that the CPE was due to the CSF and not to non specific changes in the cultures. CPE was seen in cultures in which mycoplasmas could not be detected. Degenerated cultures show polymorphous nuclei with condensed nuclear chromatin and enlarged mitochondria with few cristae but virus particles were not identified. The physical properties of the agent in the CSF that induced the CPE were the same as those reported earlier for CSF from schizophrenic patients.