Low cerebrospinal fluid concentration of brain-specific protein D2 in patients with normal pressure hydrocephalus

Alterations of Plasmatic Biomarkers of Neurodegeneration in Mucopolysaccharidosis Type II Patients Under Enzyme Replacement Therapy

Mucopolysaccharidosis type II (MPS II) is a disorder caused by a deficient activity of iduronate-2-sulfatase, a lysosomal enzyme responsible for degrading glycosaminoglycans (GAGs). The abnormal storage of GAGs within lysosomes disrupts cellular homeostasis and leads to a severe symptomatology. Patients present neuropsychiatric impairment characterized by mental retardation and impaired cognition. The aim of this study was to quantify four neurodegeneration biomarkers in plasma: brain-derived neurotrophic factor (BDNF), platelet-derived growth factor (PDGF-AA), neural cell adhesion molecule (NCAM) and cathepsin-D, as well as to identify possible correlations with urinary GAGs in seven patients undergoing treatment with ERT (Elaprase® 0.5 mg/kg of body weight). Patients with both severe and attenuated forms of MPS II showed signs of neurodegeneration in neuroimaging exams. Patients have a decrease in BDNF and PDGF-AA concentrations, and an increase in NCAM level compared to controls. No alterations in cathepsin-D concentration were seen. GAGs levels were higher in patients than in controls, but no significant correlations between GAGs and biomarkers were observed. These results evidence that patients have neurodegeneration and that monitoring these biomarkers might be useful for assessing this process. To this date, this is the first work to analyze these plasmatic markers of neurodegeneration in patients.

Molecular profile and peripheral markers of neurodegeneration in patients with Niemann-Pick type C: Decrease in Plasminogen Activator Inhibitor type 1 and Platelet-Derived Growth Factor type AA

Niemann-Pick type C1 (NPC1) is a fatal inherited disease, caused by pathogenic variants in NPC1 gene, which leads to intracellular accumulation of non-esterified cholesterol and glycosphingolipids. This accumulation leads to a wide range of clinical manifestations, including neurological and cognitive impairment as well as psychiatric disorders. The pathophysiology of cerebral damage involves loss of Purkinje cells, synaptic disturbance, and demyelination. Miglustat, a reversible inhibitor of glucosylceramide synthase, is an approved treatment for NPC1 and can slow neurological damage. The aim of this study was to assess the levels of peripheric neurodegeneration biomarkers of NPC1 patients, namely brain-derived neurotrophic factor (BDNF), platelet-derived growth factors (PDGF-AA and PDGF-AB/BB), neural cell adhesion molecule (NCAM), PAI-1 Total and Cathepsin-D, as well as the levels of cholestane-3β,5α,6β-triol (3β,5α,6β-triol), a biomarker for NPC1. Molecular analysis of the NPC1 patients under study was performed by next generation sequencing (NGS) in cultured fibroblasts. We observed that NPC1 patients treated with miglustat have a significant decrease in PAI-1 total and PDGF-AA concentrations, and no alteration in BDNF, NCAM, PDGF-AB/BB and Cathepsin D. We also found that NPC1 patients treated with miglustat have normalized levels of 3β,5α,6β-triol. The molecular analysis showed four described mutations, and for two patients was not possible to identify the second mutated allele. Our results indicate that the decrease of PAI-1 and PDGF-AA in NPC1 patients could be involved in the pathophysiology of this disease. This is the first work to analyze those plasmatic markers of neurodegenerative processes in NPC1 patients.

NCAM1 is the Target of miRNA-572: Validation in the Human Oligodendroglial Cell Line

The neural cell adhesion molecule 1 (NCAM1) is a fundamental protein in cell-cell interaction and in cellular developmental processes, and its dysregulation is involved in a number of diseases including multiple sclerosis. Studies in rats suggest that the modulation of NCAM1 expression is regulated by miRNA-572, but no data are available confirming such interaction in the human system. We analyzed whether this is the case using a human oligodendroglial cell line (MO3.13). MO3.13 cells were transfected with miRNA-572 mimic and inhibitor separately; NCAM1 mRNA and protein expression levels were analyzed at different time points after transfection. Results indicated that NCAM1 expression is increased after transfection with miRNA-572 inhibitor, whereas it is decreased after transfection with the mimic (p < 0.005). The interaction between NCAM1 and miRNA-572 was subsequently confirmed in a Vero cell line that does not express NCAM1, by luciferase assay after transfection with NCAM1. These results confirm that miRNA-572 regulates NCAM1 and for the first time demonstrate that this interaction regulates NCAM1 expression in human cells. Data herein also support the hypothesis that miRNA-572 is involved in diseases associated with NCAM1 deregulation, suggesting its possible use as a biomarker in these diseases.

Neural cell adhesion molecules in brain plasticity and disease

Neural cell adhesion molecule (NCAM) has been studied extensively. But it is only in recent times that interest in this molecule has shifted to conditions such as Alzheimer's disease, Multiple Sclerosis and Schizophrenia, focusing on its role in neurodegeneration and abnormal neurodevelopment. NCAM is important in neurite outgrowth, long-term potentiation in the hippocampus and synaptic plasticity. Reduced as well as increased levels in NCAM have been linked to pathology in the brain suggesting that a shift in the equilibrium may be the key. Hence, increasing our understanding of the role of NCAM in health and disease should clear some of the ambiguity surrounding the molecule and even lead to newer potential therapeutic targets. This review consolidates our current understanding of NCAM, focusing on the consequences of dysregulation, its role in neurodegenerative and neurodevelopmental disorders, and the future of NCAM plus potential options for therapy.

Ongoing search for diagnostic biomarkers in idiopathic normal pressure hydrocephalus

Idiopathic normal pressure hydrocephalus is a syndrome, which typically has a clinical presentation of gait/balance disturbance, often accompanied by cognitive decline and/or urinary incontinence. Its diagnosis is based on relevant history and clinical examination, appropriate imaging findings and physiological testing. The clinical picture of idiopathic normal pressure hydrocephalus may occasionally be difficult to distinguish from that of Alzheimer’s dementia, subcortical ischemic vascular dementia and Parkinson’s disease. The aim of this article is to systematically review the literature from the last 29 years in order to identify cerebrospinal fluid (CSF) or imaging biomarkers that may aid in the diagnosis of the syndrome. The authors concluded that no CSF or imaging biomarker is currently fulfilling the criteria required to aid in the diagnosis of the condition. However, a few studies have revealed promising CSF and imaging markers that need to be verified by independent groups. The reasons that the progress in this field has been slow so far is also commented on, as well as steps required to apply the current evidence in the design of future studies within the field.

Neural cell adhesion molecule (NCAM) and prealbumin in cerebrospinal fluid from depressed patients

The size of the soluble form of the human cerebrospinal fluid (CSF) neural cell adhesion molecule, NCAM-sol, was by gel permeation chromatography estimated to 160-250 kDa. Within the CSF the concentration of NCAM-sol was found about 15-25% increased in lumbar fluid and 25% increased in ventricular fluid, both compared to cisternal fluid. Whereas prealbumin was found evenly distributed in CSF, albumin was relatively enriched in lumbar fluid. The concentrations of NCAM-sol and prealbumin were measured in lumbar CSF from psychiatric patients. Prealbumin was increased 7.2% and NCAM-sol was decreased 15.1% in depressed patients. The changes were partially normalized during recovery from the depression. The findings can be explained by hypothesizing that endogenous depression is associated with an increased choroid plexus activity and CSF production.

Screening tests for normal-pressure hydrocephalus: sensitivity, specificity, and cost

Object

Many tests have been proposed to help choose candidates for shunt insertion in cases of suspected normal-pressure hydrocephalus (NPH). It is unclear what sensitivity and specificity a prospective test must have to improve outcomes, compared with the results of automatic shunt insertion.

Methods

The authors adapted the decision analysis model used in a companion article to allow for application of a screening test. Using the reported sensitivities and specificities of several such tests, they evaluated the effects such tests would have on the expected outcome of an average 65-year-old patient with moderate dementia. They also evaluated the cost-effectiveness of a theoretical screening test with superior sensitivity and specificity.

Conclusions

Although external lumbar drainage comes quite close, none of the screening tests reported to date have sufficient sensitivity and specificity to improve expected outcome in an average candidate, compared with the results of automatic shunt placement in cases of suspected NPH. In addition, even a theoretically improved test would need to be considerably less expensive than prolonged lumbar drainage to be cost-effective in clinical practice.

Biomarkers in chronic adult hydrocephalus

Awareness of the importance of chronic adult hydrocephalus has been raised again with the recent emergence of epidemiological studies. It is estimated that between 5 and 10% of patients suffering from dementia might, in fact, have chronic hydrocephalus. Although, surgical diversion of the cerebrospinal fluid (CSF) represents the only known procedure able to treat the symptoms of this condition, the selection of surgical patients has always been problematic. In the last 40 years, we have become wiser in using appropriate diagnostic tests for the selection of these patients; however, the area of biological markers has so far been overlooked in this condition, in contrast to that for other neurodegenerative disorders and dementias. Biomarkers are biological substances that may be used to indicate either the onset or the presence, and the progression of a clinical condition, being closely linked to its pathophysiology. In such a setting they might assist in the more appropriate selection of patients for shunt surgery. In this article, we have reviewed research carried out in the last 25 years regarding the identification of serum and CSF biomarkers for chronic hydrocephalus, discussed the potential for each one, and finally discussed the limitations for use, as well as future directions and possibilities in this field. It is concluded that tumour-necrosis factor, tau protein, lactate, sulfatide and neurofilament triple protein are the most promising CSF markers for chronic hydrocephalus. At present however, none of these meet the criteria required to justify a change clinical practice. In the future, collaborative multi-centre projects will be needed to obtain more substantial data that overcome the problems that arise from small individual and uncoordinated studies.

Neural cell adhesion molecule (NCAM) as a quantitative marker in synaptic remodeling

The neural cell adhesion molecule (NCAM) participates in adhesion and neuritic outgrowth during nervous system development. In the adult brain, NCAM is considered to be involved in neuronal sprouting and synaptic remodeling. The NCAM concentration of brain tissue has proved to be a useful marker of these processes, especially when viewed in comparison with the concentration of a marker of mature synapses, e.g. D3-protein (SNAP-25) or synaptophysin. The present review focusses on studies of adult brain in which NCAM concentration estimates and NCAM/D3 ratios have been used to evaluate the rate of synaptic remodeling in brain damage and degenerative diseases.

CSF and serum brain-specific creatine kinase isoenzyme (CK-BB), neuron-specific enolase (NSE) and neural cell adhesion molecule (NCAM) as prognostic markers for hypoxic brain injury after cardiac arrest in man

Creatine kinase (CK) and its brain-specific isoenzyme (CK-BB), neuron-specific enolase (NSE), neural cell adhesion molecule (NCAM) and the ions sodium, potassium, chloride and calcium were measured both in CSF and serum and inorganic phosphate in CSF in order to assess their prognostic value in total brain ischemia due to cardiac arrest. The samples were collected at 4, 28 and 76 h after resuscitation. Twenty consecutive patients resuscitated from ventricular fibrillation or asystole were included in the study. Nine of the patients recovered consciousness (recovered) but eleven remained comatose (disabled). The follow-up period was 2 years after which only one patient was still alive. The earliest statistically significant differences between neurologically recovered and disabled patient groups were seen in CSF inorganic phosphate (P = 0.030) already at 4 h and CK-BB (P = 0.046) and NSE (P = 0.020) activity at 28 h. Later, at 76 h after the resuscitation CSF NSE differentiated the groups most clearly (P = 0.014). The values were higher in the disabled patients. A negative correlation between CSF parameters and Glasgow Coma scores was also seen at these timepoints. Statistically significant differences between the groups were seen in both CSF and blood pCO2, pO2, base excess (BE) and actual bicarbonate (HCO3-). CSF or serum NCAM has no prognostic value in anoxic-ischemic coma. The results suggest that in CSF CK-BB and NSE are useful prognostic indicators of hypoxic brain injury when measured 28-76 h after cardiac arrest whereas blood samples have no prognostic value.

Cerebrospinal fluid markers in neurological disorders

Cerebrospinal fluid (CSF) markers are a useful tool for determining disease progression or activity in some neurological disorders which need parameters both for evaluating treatments and investigating pathobiological evolution in research-oriented follow-up. A number of CSF proteins are reviewed with data on biological properties, analytical methods, clinical usefulness of: myelin basic protein, S-100 protein, glial fibrillary acidic protein, neural-cell adhesion molecule, neuron-specific enolase and others.

Embryonic neural cell adhesion molecule in cerebrospinal fluid of younger children: age-dependent decrease during the first year

Poly-alpha-2,8-N-acetylneuraminic acid (poly-alpha-2,8-NeuAc) is developmentally expressed in neural tissue of higher animals, where it is covalently attached to the neural cell adhesion molecule (NCAM), a large integral membrane glycoprotein mediating cell-cell adhesion during neuronal development. NCAM exists in several molecular forms, of which only embryonic NCAM carries lengthy chains (n greater than 5) of poly-alpha-2,8-NeuAc. Chemically identical poly-alpha-2,8-NeuAc of bacterial origin is an important virulence factor in infections caused by Neisseria meningitidis group B and Escherichia coli K1, the predominant pathogens of bacterial meningitis. A quantitative enzyme-linked immunoassay was developed using monoclonal antibody (MAb) 735, an MAb specifically recognizing poly-alpha-2,8-NeuAc, and applied to CSF specimens from younger children. Poly-alpha-2,8-NeuAc contents were within the range of 20-0.2 micrograms/ml, decreasing from day 1 to day 300. Immunoprecipitation, immunoblot with a rabbit anti-mouse NCAM serum recognizing the protein part of human NCAM by cross-reactivity, affinity enrichment using immobilized MAb 735, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that poly-alpha-2,8-NeuAc in CSF is bound to human NCAM, probably NCAM-120.

Neuropeptides and neural cell adhesion molecule (NCAM) in CSF from patients with ALS

In 10 patients with amyotrophic lateral sclerosis (ALS), the CSF content of the neuropeptides vasoactive intestinal polypeptide (VIP) and cholecystokinin (CCK) as well as neural cell adhesion molecule (NCAM) was investigated. Compared with normal controls, no deviations were found in CCK or NCAM, while the values of VIP were significantly lower in ALS patients. This finding may reflect a loss of motor neurons.

Soluble neural cell adhesion molecule in brain, cerebrospinal fluid and plasma in the developing rat

Neural cell adhesion molecule (NCAM) is a glycoprotein found in neurons, glial cells and muscle cells. In this report we describe the polypeptide composition and amount of soluble NCAM in brain, cerebrospinal fluid (CSF) and plasma in rats of various ages. One-two percent of total NCAM in rat brain was shown to be buffer-soluble. Soluble NCAM in brain, extracted at pH 7.2, constituted an increasing relative proportion of total NCAM during development, whereas the concentration of soluble NCAM in both CSF and plasma decreased in the same period. By radioiodination of brain extracts, CSF, and plasma, soluble NCAM was found to be composed of up to five polypeptides with molecular weights (Mr) of 200,000, 170,000, 150,000, 115,000 and 80,000. The relative composition did not vary significantly with age. The major forms in brain were the polypeptides with Mr of 200,000 and 115,000, whereas in CSF all forms seemed to appear in equal amounts. In plasma the 200,000 and the 170,000 Mr polypeptides were not observed and here the major forms were the 150,000 and 115,000 Mr polypeptides.

The expression of an N-CAM serum fragment is positively correlated with severity of negative features in type II schizophrenia

The expression of a 70-kD serum fragment of the neural cell adhesion molecule (N-CAM) in schizophrenia is described. Schizophrenic patients (n = 40) were found to have statistically significant increases (p less than 0.0001) in serum N-CAM levels when compared to normal individuals (n = 26), and this could not be associated with age or sex. This difference was more marked (p less than 0.0001) between type II schizophrenics (n = 13) and normal individuals (n = 26) than when patients in the overlap group between type I and type II schizophrenia (n = 18) were compared to normal individuals (p less than 0.001). This difference remained significant (p less than 0.01) when overlap patients were compared to those of type II schizophrenia. Furthermore, schizophrenic patients with lower serum N-CAM proved to be better responders to neuroleptic therapy. We suggest that these elevated serum N-CAM levels reflect an increased synaptic turnover rate in this psychotic state.

High cerebrospinal fluid concentration of glial fibrillary acidic protein (GFAP) in patients with normal pressure hydrocephalus

The concentration of glial fibrillary acidic protein (GFAP) in lumbar cerebrospinal fluid (CSF) was measured in 12 patients with normal pressure hydrocephalus (NPH) 11 patients with primary degenerative dementia (PDD), 8 patients with various other neurological diseases, and 18 patients without signs of organic nervous disease (controls). Mean CSF GFAP concentration was significantly higher in NPH patients: 96 +/- 23 ng/ml (SEM) when compared with PDD patients: 8.2 +/- 1.9 ng/ml (P less than 0.01), or with controls: 4.3 +/- 0.7 ng/ml (P less than 0.01). Only 2 NPH patients had a GFAP concentration within the range of the control group (2-14 ng GFAP/ml CSF). No significant differences were found between the PDD patients and the control group, or between the group of patients with other neurological diseases and the control group. In addition, a rostro-caudal gradient of GFAP in CSF could be demonstrated. In 6 NPH and 2 PDD patients both ventricular and lumbar CSF samples were investigated. In all cases the ventricular GFAP concentration was higher than the lumbar concentration. The difference was statistically significant (P less than 0.01). Our results suggest that determination of CSF GFAP concentration might be of diagnostic value in discrimination between NPH patients and patients with enlarged ventricles associated with degenerative brain disease.

Impermeability of the blood-cerebrospinal fluid barrier to 1-deamino-8-D-arginine-vasopressin (DDAVP) in patients with acquired, communicating hydrocephalus

The passage of the vasopressin analogue, 1-deamino-8-D-arginine-vasopressin (DDAVP) into the cerebrospinal fluid (CSF) following intravenous (i.v.) administration was studied in human subjects. After i.v. injection of DDAVP, resulting in plasma levels exceeding normal plasma concentrations of vasopressin (AVP) by 100-fold, serial blood and ventricular CSF specimens were sampled during 2 h. Plasma and CSF were analysed by radioimmunoassay using two different AVP antisera: one specific against natural AVP and another cross-reacting 100% with DDAVP. No changes in the joint concentrations of DDAVP + AVP in CSF were found following i.v. infusion of DDAVP when compared with the concentration before the infusion. Neither was any difference between CSF concentrations of AVP and DDAVP + AVP observed at any sampling time following the i.v. DDAVP administration. Hence, it is concluded that no measurable amounts of DDAVP can be found in the CSF for up to 2 h after i.v. administration of the peptide, and that for all practical purposes a blood-CSF barrier to DDAVP exists.