alpha-synuclein and Hydrocephalus--Normal-Pressure

Cerebrospinal fluid (CSF) is sequestered from blood by the blood-brain barrier and directly communicates with brain parenchymal interstitial fluid, leading to contain specific biomarkers of neurological diseases.. CSF contains glycan isoforms of transferrin (Tf): one appears to be derived from the brain and the other from blood.. CSF contains two glycan-isoforms; brain-type Tf and serum-type Tf. Glycan analysis and immunohistochemistry suggest that serum-type Tf having α2, 6sialylated glycans is derived from blood whereas brain-type Tf having GlcNAc-terminated glycans is derived from the choroid plexus, CSF producing tissue. The ratio of serum-type/brain-type Tf differentiates Alzheimer's disease from idiopathic normal pressure hydrocephalus, which is an elderly dementia caused by abnormal metabolism of CSF. The ratios in Parkinson's disease (PD) patients were higher than those of controls and did not appear to be normally distributed. Indeed, detrended normal Quantile-Quantile plot analysis reveals the presence of an independent subgroup showing higher ratios in PD patients. The subgroup of PD shows higher levels of CSF α-synuclein than the rest, indicating that PD includes two subgroups, which differ in levels of brain-type Tf and α-synuclein.. Glycosylation in central nervous system appears to be unique. The unique glycan may be a tag for glycoprotein, which is biosynthesized in the central nervous system. This article is part of a Special Issue entitled Neuro-glycoscience, edited by Kenji Kadomatsu and Hiroshi Kitagawa.

Topics: alpha-Synuclein; Biomarkers; Choroid Plexus; Dementia; Diagnosis, Differential; Glycosylation; Humans; Hydrocephalus, Normal Pressure; Parkinson Disease; Polysaccharides; Protein Isoforms; Protein Processing, Post-Translational; Transferrin

Idiopathic normal pressure hydrocephalus (iNPH) is a clinico-radiological syndrome of elderly individuals likely sustained by different neurodegenerative changes as copathologies. Since iNPH is a potentially reversible condition, assessing neurodegenerative pathologies in vitam through CSF biomarkers and their influence on clinical features and surgical outcome represents crucial steps.. We measured α-synuclein seeding activity related to Lewy body (LB) pathology by the real-time quaking-induced conversion assay (RT-QuIC) and Alzheimer disease core biomarkers (proteins total-tau, phospho-tau, and amyloid-beta) by immunoassays in the cerebrospinal fluid (CSF) of 293 iNPH patients from two independent cohorts. To compare the prevalence of LB copathology between iNPH participants and a control group representative of the general population, we searched for α-synuclein seeding activity in 89 age-matched individuals who died of Creutzfeldt-Jakob disease (CJD). Finally, in one of the iNPH cohorts, we also measured the CSF levels of neurofilament light chain protein (NfL) and evaluated the association between all CSF biomarkers, baseline clinical features, and surgery outcome at 6 months.. Sixty (20.5%) iNPH patients showed α-synuclein seeding activity with no significant difference between cohorts. In contrast, the prevalence observed in CJD was only 6.7% (p = 0.002). Overall, 24.0% of iNPH participants showed an amyloid-positive (A+) status, indicating a brain co-pathology related to Aβ deposition. At baseline, in the Italian cohort, α-synuclein RT-QuIC positivity was associated with higher scores on axial and upper limb rigidity (p = 0.003 and p = 0.011, respectively) and lower MMSEc scores (p = 0.003). A+ patients showed lower scores on the MMSEc (p = 0.037) than A- patients. Higher NfL levels were also associated with lower scores on the MMSEc (rho = -0.213; p = 0.021). There were no significant associations between CSF biomarkers and surgical outcome at 6 months (i.e. responders defined by decrease of 1 point on the mRankin scale).. Prevalent LB- and AD-related neurodegenerative pathologies affect a significant proportion of iNPH patients and contribute to cognitive decline (both) and motor impairment (only LB pathology) but do not significantly influence the surgical outcome at 6 months. Their effect on the clinical benefit after surgery over a more extended period remains to be determined.

Topics: Aged; alpha-Synuclein; Amyloid beta-Peptides; Biomarkers; Humans; Hydrocephalus, Normal Pressure; Lewy Bodies; Peptide Fragments; Prevalence; tau Proteins

This study quantified the occurrence of an underlying synucleinopathy in 50 patients with idiopathic normal pressure hydrocephalus by means of real-time quaking-induced conversion, a highly sensitive and specific technique capable of detecting and amplifying misfolded aggregated forms of α-synuclein in the cerebrospinal fluid. Seven patients were positive and they did not differ from negative cases, except for a more frequent L-dopa responsiveness and gait characterized by a wider base. The two groups did not differ in terms of response rate to tap test or shunt surgery, although step length and gait velocity improved by a lesser extent in positive cases. ANN NEUROL 2022;92:985-991.

Topics: alpha-Synuclein; Gait; Humans; Hydrocephalus, Normal Pressure; Synucleinopathies

The pathophysiology of neurodegeneration is complex. Its diagnosis requires an early identification of sequential changes in several hallmarks in the brains of affected subjects. The presence of brain pathology can be visualized in the cerebrospinal fluid (CSF) by protein profiling. It is clear that the field of Alzheimer's disease (AD) will benefit from an integration of algorithms including CSF concentrations of individual proteins, especially as an aid in clinical decision-making or to improve patient enrolment in clinical trials. The protein profiling approach requires standard operating procedures for collection and storage of CSF which must be easy to integrate into a routine clinical lab environment. Our study provides recommendations for analysis of neurogranin trunc P75, α-synuclein, and tau, in combination with the ratio of β-amyloid Aβ(1-42)/Aβ(1-40).. Protocols for CSF collection were compared with CSF derived from subjects with normal pressure hydrocephalus (n = 19). Variables included recipient type (collection, storage), tube volume, and addition of detergents at the time of collection. CSF biomarker analysis was performed with enzyme-linked immunosorbent assays (ELISAs). Data were analyzed with linear repeated measures and mixed effects models.. Adsorption to recipients is lower for neurogranin trunc P75, α-synuclein, and tau (<10%), as compared to Aβ(1-42). For neurogranin trunc P75 and total tau, there is still an effect on analyte concentrations as a function of the tube volume. Protocol-related differences for Aβ(1-42) can be normalized at the (pre-)analytical level using the ratio Aβ(1-42)/Aβ(1-40), but not by using the ratio Aβ(1-42)/tau. The addition of detergent at the time of collection eliminates differences due to adsorption.. Our study recommends the use of low protein binding tubes for quantification in CSF (without additives) of all relevant CSF biomarkers. Pre-analytical factors have less effect on α-synuclein, neurogranin trunc P75, and total tau, as compared to Aβ(1-42). The ratio of Aβ(1-42)/Aβ(1-40), but not Aβ(1-42)/tau, can be used to adjust for pre-analytical differences in analyte concentrations. Our study does not recommend the inclusion of detergents at the time of collection of CSF. The present results provide an experimental basis for new recommendations for parallel analysis of several proteins using one protocol for collection and storage of CSF.

Topics: alpha-Synuclein; Amyloid beta-Peptides; Belgium; Biomarkers; Cerebrospinal Fluid; Enzyme-Linked Immunosorbent Assay; Female; Humans; Hydrocephalus, Normal Pressure; Male; Middle Aged; Neurogranin; Peptide Fragments; Practice Guidelines as Topic; Reproducibility of Results; Sensitivity and Specificity; Specimen Handling; tau Proteins

Patients presenting with the classical idiopathic normal pressure hydrocephalus (iNPH) triad often show additional parkinsonian spectrum signs. Accurate differential diagnosis strongly influences the long-term outcome of cerebrospinal fluid (CSF) shunting.. The aim of this study was to find potential CSF microRNA (miRNA) biomarkers for NPH mimics with parkinsonian syndromes that can reliably distinguish them from iNPH patients.. Two cohorts of 81 patients (cohort 1, n = 55; cohort 2, n = 26) with possible iNPH who were treated in two centers between January 2011 and May 2014 were studied. In both cohorts, CSF samples were obtained from patients clinically diagnosed with iNPH (n = 21 and n = 10, respectively), possible iNPH with parkinsonian spectrum (PS) (n = 18, n = 10, respectively), possible iNPH with Alzheimer's disease (AD) (n = 16), and non-affected elderly individuals (NC) (n = 6). A three-step qRT-PCR analysis of the CSF samples was performed to detect miRNAs that were differentially expressed in the groups.. The expression of hsa-miR-4274 in CSF was decreased in both cohorts of PS group patients (cohort 1: p < 0.0001, cohort 2: p < 0.0001), and was able to distinguish PS from iNPH with high accuracy (area under the curve = 0.908). The CSF concentration of hsa-miR-4274 also correlated with the specific binding ratio of ioflupane (123I) dopamine transporter scan (r = -0.494, p = 0.044). By contrast, the level of hsa-miR-4274 was significantly increased in the PS group after CSF diversion.. Levels of CSF hsa-miR-4274 can differentiate PS from patients with iNPH, AD, and NC. This may be clinically useful for diagnostic purposes and predicting shunt treatment responses.

Topics: Aged; Aged, 80 and over; alpha-Synuclein; Amyloid beta-Peptides; Amyloid beta-Protein Precursor; Cohort Studies; Female; Gene Expression Regulation; Humans; Hydrocephalus, Normal Pressure; Male; MicroRNAs; Parkinsonian Disorders; Peptide Fragments; RNA, Messenger

The source of Parkinson disease-linked α-synuclein (aSyn) in human cerebrospinal fluid (CSF) remains unknown. We decided to measure the concentration of aSyn and its gradient in human CSF specimens and compared it with serum to explore its origin. We correlated aSyn concentrations in CSF versus serum (Q(aSyn)) to the albumin quotient (Q(albumin)) to evaluate its relation to blood-CSF barrier function. We also compared aSyn with several other CSF constituents of either central or peripheral sources (or both) including albumin, neuron-specific enolase, β-trace protein and total protein content. Finally, we examined whether aSyn is present within the structures of the choroid plexus (CP). We observed that Q(aSyn) did not rise or fall with Q(albumin) values, a relative measure of blood-CSF barrier integrity. In our CSF gradient analyses, aSyn levels decreased slightly from rostral to caudal fractions, in parallel to the recorded changes for neuron-specific enolase; the opposite trend was recorded for total protein, albumin and β-trace protein. The latter showed higher concentrations in caudal CSF fractions due to the diffusion-mediated transfer of proteins from blood and leptomeninges into CSF in the lower regions of the spine. In postmortem sections of human brain, we detected highly variable aSyn reactivity within the epithelial cell layer of CP in patients diagnosed with a range of neurological diseases; however, in sections of mice that express only human SNCA alleles (and in those without any Snca gene expression), we detected no aSyn signal in the epithelial cells of the CP. We conclude from these complementary results that despite its higher levels in peripheral blood products, neurons of the brain and spinal cord represent the principal source of aSyn in human CSF.

Topics: Adult; Aged; Aged, 80 and over; alpha-Synuclein; Biomarkers; Brain; Choroid Plexus; Female; Humans; Hydrocephalus, Normal Pressure; Intramolecular Oxidoreductases; Lipocalins; Male; Middle Aged; Neurons; Phosphopyruvate Hydratase