12 research outputs found
The role of insulin resistance and APOE genotype on blood–brain barrier integrity in Alzheimer's disease
No full textAbstract INTRODUCTION Growing evidence suggests a connection between insulin resistance and apolipoprotein E ( APOE ) genotype in Alzheimer's disease (AD) pathogenesis, but the mechanisms are unclear. We examined effects of insulin resistance and APOE genotype on blood–brain barrier (BBB) integrity in AD. METHODS BBB integrity was measured in 196 biologically‐confirmed non‐diabetic patients with AD evaluating CSF/serum albumin ratio, kappa and lambda free light chains (FLCs). Insulin resistance was assessed using triglyceride–glucose index (TyG). The impact of TyG on BBB integrity, and its interaction with APOE genotypes, was analyzed using multivariate models. RESULTS Sixty‐four percent of patients with AD showed altered TyG, with the 21.8% classified as high TyG. TyG subgroups were associated with BBB abnormalities, with similar AD clinical and biomarkers profile. A significant interaction between TyG and APOE ε4/ε4 genotype on BBB permeability was found in multivariate analyses. DISCUSSION Insulin resistance is a common feature in non‐diabetic AD and correlates with altered BBB permeability, interacting synergistically with APOE genotype. Highlights Insulin resistance and apolipoprotein E ( APOE ) genotype are well‐recognized risk factors for Alzheimer's disease (AD). Insulin resistance shows high prevalence in patients with AD. Insulin resistance is related to damage in blood–brain barrier (BBB) integrity. The association between the triglyceride–glucose (TyG) index and BBB permeability varies in relation to APOE genotype; patients with the APOE ε4/ε4 displayed higher BBB permeability
Unveiling New Genetic Variants Associated with Age at Onset in Alzheimer's Disease and Frontotemporal Lobar Degeneration Due to C9orf72 Repeat Expansions
No full textAlzheimer's disease (AD) and Frontotemporal lobar degeneration (FTLD) represent the most common forms of neurodegenerative dementias with a highly phenotypic variability. Herein, we investigated the role of genetic variants related to the immune system and inflammation as genetic modulators in AD and related dementias. In patients with sporadic AD/FTLD (n = 300) and GRN/C9orf72 mutation carriers (n = 80), we performed a targeted sequencing of 50 genes belonging to the immune system and inflammation, selected based on their high expression in brain regions and low tolerance to genetic variation. The linear regression analyses revealed two genetic variants: (i) the rs1049296 in the transferrin (TF) gene, shown to be significantly associated with age at onset in the sporadic AD group, anticipating the disease onset of 4 years for each SNP allele with respect to the wild-type allele, and (ii) the rs7550295 in the calsyntenin-1 (CLSTN1) gene, which was significantly associated with age at onset in the C9orf72 group, delaying the disease onset of 17 years in patients carrying the SNP allele. In conclusion, our data support the role of genetic variants in iron metabolism (TF) and in the modulation of the calcium signalling/axonal anterograde transport of vesicles (CLSTN1) as genetic modulators in AD and FTLD due to C9orf72 expansions
The Impact of Insulin Resistance on Grey Matter Changes Along the Alzheimer’s Disease Continuum Insulin Resistance and Grey Matter in AD
No full textAbstract Background and Objectives Insulin resistance is emerging as a modifiable risk factor for Alzheimer’s, though its impact on grey matter volume across clinical stages remains poorly understood. The objective of the research is to investigate how insulin resistance affects grey matter integrity across the Alzheimer’s disease continuum using structural MRI. Methods Imaging, clinical, and metabolic data were extracted from 374 non-diabetic participants within the Alzheimer’s Disease Neuroimaging Initiative (ADNI) dataset. Participants were classified as cognitively impaired (CI: n=186; 137 mild cognitive impairment, 49 early-to-moderate dementia; all AD biomarker positive) or cognitively unimpaired (CU: n=188; 122 amyloid-negative, 66 amyloid-positive). Insulin resistance was assessed at the time of MRI and clinical evaluation using the dichotomized triglyceride-glucose index (TyG). The Interactions between TyG and diagnostic group on grey matter volume were investigated using both voxel-wise and region-of-interest (ROI) based analyses, adjusted for age, sex, education, vascular risk factors, and global cognitive performance across the AD continuum. Results Insulin resistance significantly impacted gray matter volume across the AD continuum, demonstrating stage-dependent effects. In early AD disease stages, insulin resistance was associated with lower grey matter volume in fronto-parietal regions, a finding that extended to several cortical areas in CI individuals. Temporal and fronto-limbic regions were particularly highlighted by the IR-diagnosis interaction. In amyloid-positive CU individuals, IR was linked to bilateral temporal atrophy, in contrast to amyloid-negative CU participants. Discussion This study underscores the impact of insulin resistance on brain structure across the AD continuum, particularly within key vulnerability areas characteristic of AD pathology. These findings highlight the need for future research into potential therapeutic strategies targeting insulin signaling to mitigate neurodegeneration in AD
Plasma p-tau181 and amyloid markers in Alzheimer's disease: A comparison between Lumipulse and SIMOA
No full textAim of the project was to evaluate the technical and clinical validity of plasma Lumipulse p-tau, A(342 and A(340 species and their correlation with CSF core Alzheimer's Disease (AD) markers; a method comparison with SIMOA was also performed. One-hundred-thirthy-three participants, namely 55 A+T+N+ AD, 28 Neurodegenerative disorders (NDD) and 50 controls were enrolled for the study. Lumipulse technical validity showed high stability for p-tau181, A(342, and A(340, with higher stability of p-tau to repeated freezing thaw cycles. p-tau181 levels detected by both techniques were higher in AD compared to both NDD/controls and exhibited a similar correlation with CSF p-tau levels, whereas A(342 levels were slightly lower in AD with both methods. In the comparison between SIMOA and Lumipulse plasma markers, both techniques exhibited similar diagnostic accuracy for AD for p-tau181 (0.87; 95 %CI 0.81-0.94, vs 0.85; 95 %CI 0.78-0.93), whereas the best performance was reached by p-tau181/ A(342 Lumipulse ratio (ROC AUC 0.915, 95 %CI 0.86-0.97). The study thus confirmed the construct validity of both Lumipulse and SIMOA techniques for the identification of CSF AD pattern in clinical settings
Alterations of NMDAR Subunits in the Cerebrospinal Fluid Across Neurodegenerative and Immunological Disorders
No full textN-methyl-D-aspartate receptors (NMDARs) are glutamate-binding calcium channels that play a key role in brain function and have been linked to many neurological disorders. NMDARs are multi-pass membrane heterotetrameric complexes composed of two compulsory GluN1 subunits and two GluN2 (A-D) or GluN3 (A-B) subunits, from which GluN1, GluN2B, GluN2A, and GluN3A are widely expressed in the adult brain. This study assesses the presence of GluN1, GluN2B, GluN2A, and GluN3A in the cerebrospinal fluid (CSF) from healthy individuals, viral and autoimmune encephalitis, Huntington's disease (HD) and Alzheimer's disease (AD) patients. Samples were run in SDS-PAGE under reducing conditions and resolved with different anti-ectodomain and anti-C-terminal antibodies that combined with immunoprecipitation analyses, served to demonstrate the presence of full-length GluN1, GluN2A, GluN2B, and GluN3A in CSF. These NMDAR subunit complexes are not associated with extracellular vesicles. As a proof of concept of the identity of NMDAR subunits in the CSF, we demonstrated reduced levels of GluN1 in the CSF from patients with autoimmune encephalitis caused by anti-GluN1 antibodies compared with other causes of encephalitis; and showed a depletion of CSF GluN3A in a Grin3a knockout mouse model. Moreover, we observed higher GluN3A levels in CSF in both asymptomatic and symptomatic HD patients; while GluN2A levels were lower in CSF from AD patients. In conclusion, here we demonstrate the presence of NMDAR full-length subunits in CSF and that changes in NMDAR subunits balance could serve to identify alterations related to pathological conditions.This work was supported by Fondo de Investigaciones Sanitarias (PI22/01329) and Direcció General de Ciència i Investigació, Generalitat Valenciana (AICO/2021/308).We thank Prof. I. Pérez-Otaño (Instituto de Neurociencias de Alicante, CSIC-Universidad Miguel Hernández, Spain) for advice and the generous gift of the Grin3a knockout mouse. We also thank Prof. John J. Woodward (University of South Carolina, South Carolina, USA) and Juan Lerma (Instituto de Neurociencias de Alicante, CSIC-Universidad Miguel Hernández, Spain) for the generous gift of NMDA constructs; and Dr. Ricardo Rodrigues (CNC-UC-Center for Neuroscience and Cell Biology, University of Coimbra, Portugal) and Ana V. Paternain (Instituto de Neurociencias de Alicante, CSIC-Universidad Miguel Hernández, Spain) for guidance with the constructs and transfection. We thank Dr. A. Sogorb-Esteve (UK Dementia Research Institute at UCL, London) for assistance with mouse CSF extraction. This work was supported by grants from the Fondo de Investigaciones Sanitarias (PI22/01329, co-funded by the Fondo Europeo de Desarrollo Regional, FEDER “Investing in your future”), CIBERNED (Instituto de Salud Carlos III, Spain), and from the Direcció General de Ciència i Investigació, Generalitat Valenciana (AICO/2021/308) and “Severo Ochoa” Program for Centers of Excellence in R&D (CEX2021-001165-S). S.E. is supported by a PFIS fellowship from the ISC-III. APa has been supported by grants of the Italian Ministry of University and Research PRIN COCOON (2017MYJ5TH) and PRIN 2021 RePlast (20202THZAW), the H2020 IMI IDEA-FAST (ID853981), Italian Ministry of Health, Grant/Award Number: RF-2018-12366209, RF-2019-12369272 and PNRR-Health PNRR-MAD-2022-12376110. APi has been supported by grants of Airalzh Foundation AGYR2021 Life-Bio Grant, The LIMPE-DISMOV Foundation Segala Grant 2021, the Italian Ministry of University and Research PRIN COCOON (2017MYJ5TH) and PRIN 2021 RePlast (20202THZAW), the H2020 IMI IDEA-FAST (ID853981), Italian Ministry of Health, Grant/Award Number: RF-2018-12366209 and PNRR-Health PNRR-MAD-2022-12376110. C.T. is supported by the Ministry of Health PRIN 2021 RePlast. H.Z. is a Wallenberg Scholar and a Distinguished Professor at the Swedish Research Council supported by grants from the Swedish Research Council (#2023-00356, #2022-01018 and #2019-02397), the European Union's Horizon Europe research and innovation programme under grant agreement No 101053962, Swedish State Support for Clinical Research (#ALFGBG-71320), the Alzheimer Drug Discovery Foundation (ADDF), USA (#201809-2016862), the AD Strategic Fund and the Alzheimer's Association (#ADSF-21-831376-C, #ADSF-21-831381-C, #ADSF-21-831377-C, and #ADSF-24-1284328-C), the European Partnership on Metrology, co-financed from the European Union's Horizon Europe Research and Innovation Programme and by the Participating States (NEuroBioStand, #22HLT07), the Bluefield Project, Cure Alzheimer's Fund, the Olav Thon Foundation, the Erling-Persson Family Foundation, Familjen Rönströms Stiftelse, Stiftelsen för Gamla Tjänarinnor, Hjärnfonden, Sweden (#FO2022-0270), the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 860197 (MIRIADE), the European Union Joint Programme—Neurodegenerative Disease Research (JPND2021-00694), the National Institute for Health and Care Research University College London Hospitals Biomedical Research Centre, the UK Dementia Research Institute at UCL (UKDRI-1003), and an anonymous donor.With funding from the Spanish government through the "Severo Ochoa Centre of Excelence" accreditation (CEX2021-001165-S)Peer reviewe
Plasma levels of glial fibrillary acidic protein and neurofilament light chain in patients with chronic migraine: a multicenter case-control study
No full textObjectivePlasma glial fibrillary acidic protein (pGFAP) and plasma neurofilament light chain (pNfL) levels reflect astrocyte activation and neuronal damage, respectively. Whether these phenomena play a role in migraine is unknown. This study aimed to compare pGFAP and pNfL levels in patients with chronic migraine (CM) and age-matched controls and to analyze their relation with clinical features.MethodsThe study evaluated two independent cohorts of patients, including in total 58 CM and 69 controls. pGFAP and pNfL were quantified with single molecule array (Simoa) technology. Demographic and clinical data were collected for each subject; differences in NfL/GFAP levels between CM and controls were evaluated in analyses adjusted for the effect of age and sex; clinical characteristics associated with NfL/GFAP levels were separately evaluated in the two cohorts.ResultsIn both cohorts, we did not find a significant difference in pGFAP or pNFL levels between CM and matched controls. The study did not find any correlation between pGFAP or pNfL levels and any migraine characteristics (namely presence of migraine aura, attack frequency, migraine intensity, years of disease).ConclusionsOur negative results support the assumption that migraine represents a benign condition, characterized by transient functional brain alterations and not by the accumulation over time of neuroaxonal damage and/or associated astrocyte activation detectable by neurodegeneration marker proteins
Biomarker discovery in Alzheimer's and neurodegenerative diseases using Nucleic Acid Linked Immuno-Sandwich Assay
No full textIntroduction: Recent advancements in immunological methods accurately quantify biofluid biomarkers for Alzheimer's disease (AD) pathology. Despite progress, more biomarkers, ideally in blood, are needed for effective disease monitoring for AD and other neurodegenerative proteinopathies. Methods: We used the Nucleic Acid Linked Immuno-Sandwich Assay (NULISA) central nervous system panel for biomarker quantification in plasma, serum, and cerebrospinal fluid of patients with AD, mild cognitive impairment, Lewy body dementia, progranulin (GRN) mutation carriers. Results: NULISA identified phosphorylated tau217 and neurofilament light chain as the most deregulated biomarkers in the AD continuum and GRN mutation carriers, respectively. Importantly, numerous novel proteomic changes were observed in each disease endophenotype, which included synaptic processing, inflammation, microglial reactivity, TAR DNA-binding protein 43, and α-synuclein pathology. Discussion: We underline the potential of next-generation biomarker identification tools to detect novel proteomic features that also incorporate established biomarkers. These findings highlight the importance of continued biomarker discovery to improve treatment decisions and help us better understand the complexities of neurodegenerative disorders. Highlights: The, direct, or indirect, measures in blood that complement phosphorylated tau (p-tau)217 for other proteinopathies or disease progression are urgently needed. Significant novel proteomic changes were observed in each disease endophenotype in plasma, serum, and cerebrospinal fluid, which included proteins involved in synaptic processing, inflammation, microglial reactivity, TAR DNA-binding protein 43, and α-synuclein pathology. Nucleic Acid Linked Immuno-Sandwich Assay continued to unbiasely highlight p-tau217 and neurofilament light chain as the most significantly deregulated blood biomarkers in the Alzheimer's disease continuum and progranulin mutation carriers, respectively
Long pentraxin 3 as a marker of COVID-19 severity: evidences and perspectives
No full textSeveral laboratory tests are characteristically altered in Coronavirus Disease 2019 (COVID-19), but are not totally accurate in predicting the disease outcome. The long pentraxin 3 (PTX3) is quickly released directly at inflammation sites by many immune cell types. Previous studies have shown that PTX3 correlated with disease severity in various inflammatory conditions. Our study investigated the use of PTX3 as a potential marker of COVID-19 severity and compared its performance in detecting a more severe form of the disease with that of routine laboratory parameters.
Stored serum samples of RT-PCR confirmed COVID-19 cases that had been obtained at hospital admission were retrospectively analysed. Intensive care unit (ICU) stay was considered a surrogate endpoint of severe COVID-19. Pentraxin 3 was measured by a commercial enzyme-linked immunosorbent assay.
A total of 96 patients were recruited from May 1st, 2020 to June 30th, 2020; 75/96 were transferred to ICU. Pentraxin 3 was higher in ICU vs non-ICU patients (35.86 vs 10.61 ng/mL, P 18 ng/mL yielded a sensitivity of 96% and a specificity of 100% in identifying patients requiring ICU.
High values of PTX3 predict a more severe COVID-19
Increased Cerebrospinal Fluid Angiotensin-Converting Enzyme 2 Fragments as a Read-Out of Brain Infection in Patients With COVID-19 Encephalopathy
No full textInternational audienceBackground: This study assesses the cerebrospinal fluid (CSF) levels of the viral receptor angiotensin-converting enzyme 2 (ACE2) and of the serine protease TMPRSS2 fragments in patients with SARS-CoV-2 infection presenting encephalitis (CoV-Enceph). Methods The study included biobanked CSF from 18 CoV-Enceph, 4 subjects with COVID-19 without encephalitis (CoV), 21 with non-COVID-19–related encephalitis (Enceph), and 21 neurologically healthy controls. Participants underwent a standardized assessment for encephalitis. A large subset of samples underwent analysis for an extended panel of CSF neuronal, glial, and inflammatory biomarkers. ACE2 and TMPRSS2 species were determined in the CSF by western blotting.Results: ACE2 was present in CSF as several species, full-length forms and 2 cleaved fragments of 80 and 85 kDa. CoV-Enceph patients displayed increased CSF levels of full-length species, as well as the 80 kDa fragment, but not the alternative 85 kDa fragment, compared with controls and Enceph patients, characterized by increases of both fragments. Furthermore, TMPRSS2 was increased in the CSF of Enceph patients compared with controls, but not in CoV-Enceph patients. The CoV patients without encephalitis displayed unaltered CSF levels of ACE2 and TMPRSS2 species/Conclusions Patients with encephalitis displayed an overall increase in CSF ACE2, probably as a consequence of brain inflammation. The increase of the shortest ACE2 fragment only in CoV-Enceph patients may reflect the enhanced cleavage of the receptor triggered by SARS-CoV-2, thus serving to monitor brain penetrance of the virus associated with the rare encephalitis complication. TMPRSS2 changes in the CSF appeared related to inflammation, but not with SARS-CoV-2 infection
Plasma p-tau217 in Alzheimer's disease: Lumipulse and ALZpath SIMOA head-to-head comparison
No full textPlasma phosphorylated-tau217 (p-tau217) has been shown to be one of the most accurate diagnostic markers for Alzheimer's disease. No studies have compared the clinical performance of p-tau217 as assessed by the fully automated Lumipulse and single molecule array (SIMOA) AlZpath p-tau217. The study included 392 participants, 162 with Alzheimer's disease, 70 with other neurodegenerative diseases with CSF biomarkers and 160 healthy controls. Plasma p-tau217 levels were measured using the Lumipulse and ALZpath SIMOA assays. The ability of p-tau217 assessed by both techniques to discriminate Alzheimer's disease from other neurodegenerative diseases and controls was investigated using receiver operating characteristic analyses. The p-tau217 levels measured by the two techniques demonstrated a strong correlation, showing a consistent relationship with CSF p-tau181 levels. In head-to-head comparison, Lumipulse and SIMOA showed similar diagnostic accuracy for differentiating Alzheimer's disease from other neurodegenerative diseases [area under the curve (AUC) 0.952, 95% confidence interval (CI) 0.927-0.978 versus 0.955, 95% CI 0.928-0.982, respectively] and healthy controls (AUC 0.938, 95% CI 0.910-0.966 and 0.937, 95% CI 0.907-0.967 for both assays). This study demonstrated the high precision and diagnostic accuracy of p-tau217 for the clinical diagnosis of Alzheimer's disease using fully automated or semi-automated techniques
