| 61. |
- Agholme, Lotta, et al.
(author)
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Low-dose γ-secretase inhibition increases secretion of Aβ peptides and intracellular oligomeric Aβ.
- 2017
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In: Molecular and cellular neurosciences. - : Elsevier BV. - 1095-9327 .- 1044-7431. ; 85, s. 211-219
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Journal article (peer-reviewed)abstract
- γ-Secretase inhibitors have been considered promising drug candidates against Alzheimer's disease (AD) due to their ability to reduce amyloid-β (Aβ) production. However, clinical trials have been halted due to lack of clinical efficacy and/or side effects. Recent in vitro studies suggest that low doses of γ-secretase inhibitors may instead increase Aβ production. Using a stem cell-derived human model of cortical neurons and low doses of the γ-secretase inhibitor DAPT, the effects on a variety of Aβ peptides were studied using mass spectrometry. One major focus was to develop a novel method for specific detection of oligomeric Aβ (oAβ), and this was used to study the effects of low-dose γ-secretase inhibitor treatment on intracellular oAβ accumulation. Low-dose treatment (2 and 20nM) with DAPT increased the secretion of several Aβ peptides, especially Aβx-42. Furthermore, using the novel method for oAβ detection, we found that 2nM DAPT treatment of cortical neurons resulted in increased oAβ accumulation. Thus, low dose-treatment with DAPT causes both increased production of long, aggregation-prone Aβ peptides and accumulation of intracellular Aβ oligomers, both believed to contribute to AD pathology.
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| 62. |
- Aguillon, David, et al.
(author)
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Plasma p-tau217 predicts in vivo brain pathology and cognition in autosomal dominant Alzheimer's disease
- 2023
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In: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 19:6, s. 2585-2594
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Journal article (peer-reviewed)abstract
- Introduction: Plasma-measured tau phosphorylated at threonine 217 (p-tau217) is a potential non-invasive biomarker of Alzheimer's disease (AD). We investigated whether plasma p-tau217 predicts subsequent cognition and positron emission tomography (PET) markers of pathology in autosomal dominant AD. Methods: We analyzed baseline levels of plasma p-tau217 and its associations with amyloid PET, tau PET, and word list delayed recall measured 7.61 years later in non-demented age- and education-matched presenilin-1 E280A carriers (n = 24) and non-carrier (n = 20) family members. Results: Carriers had higher plasma p-tau217 levels than non-carriers. Baseline plasma p-tau217 was associated with subsequent amyloid and tau PET pathology levels and cognitive function. Discussion: Our findings suggest that plasma p-tau217 predicts subsequent brain pathological burden and memory performance in presenilin-1 E280A carriers. These results provide support for plasma p-tau217 as a minimally invasive diagnostic and prognostic biomarker for AD, with potential utility in clinical practice and trials. Highlights: Non-demented presenilin-1 E280A carriers have higher plasma tau phosphorylated at threonine 217 (p-tau217) than do age-matched non-carriers. Higher baseline p-tau217 is associated with greater future amyloid positron emission tomography (PET) pathology burden. Higher baseline p-tau217 is associated with greater future tau PET pathology burden. Higher baseline p-tau217 is associated with worse future memory performance.
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| 63. |
- Ahlgren, Erika, et al.
(author)
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Association between Plasma Homocysteine Levels and Neuronal Injury in HIV Infection
- 2016
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:7
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Journal article (peer-reviewed)abstract
- Objective To investigate the role of homocysteine in neuronal injury in HIV infection. Methods Using a cross-sectional design and archived samples, we compared concentrations of plasma homocysteine and cerebrospinal fluid (CSF) neurofilament light protein (NFL), a sensitive marker of neuronal injury, in 83 HIV-1-infected subjects without antiretroviral treatment. We also analyzed plasma vitamin B12, serum folate, CSF, and plasma HIV RNA, the immune activation marker neopterin in CSF and serum, and albumin ratio as a marker of blood-brain barrier integrity. Twenty-two subjects provided a second sample median of 12.5 months after antiretroviral treatment initiation. Results A significant correlation was found between plasma homocysteine and CSF NFL concentrations in untreated individuals (r = 0.52, p < 0.0001). As expected, there was a significant inverse correlation between homocysteine and B12 (r = -0.41, p < 0.001) and folate (r = -0.40, p = < 0.001) levels. In a multiple linear regression analysis homocysteine stood out as an independent predictor of CSF NFL in HIV-1-infected individuals. The correlation of plasma homocysteine and CSF NFL was also present in the group receiving antiretroviral therapy (r = 0.51, p = 0.016). Conclusion A correlation between plasma homocysteine and axonal injury, as measured by CSF NFL, was found in both untreated and treated HIV. While this study is not able to prove a causal link, homocysteine and functional B12/folate deficiency appear to play a role in neural injury in HIV-infected individuals.
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| 64. |
- Ahmed, R. M., et al.
(author)
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Biomarkers in dementia: clinical utility and new directions
- 2014
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In: Journal of Neurology Neurosurgery and Psychiatry. - : BMJ. - 0022-3050 .- 1468-330X. ; 85:12, s. 1426-1434
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Journal article (peer-reviewed)abstract
- Imaging, cerebrospinal fluid (CSF) and blood-based biomarkers have the potential to improve the accuracy by which specific causes of dementia can be diagnosed in vivo, provide insights into the underlying pathophysiology, and may be used as inclusion criteria and outcome measures for clinical trials. While a number of imaging and CSF biomarkers are currently used for each of these purposes, this is an evolving field, with numerous potential biomarkers in varying stages of research and development. We review the currently available biomarkers for the three most common forms of neurodegenerative dementia, and give an overview of research techniques that may in due course make their way into the clinic.
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| 65. |
- Akel, Sarah, et al.
(author)
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Neurofilament light, glial fibrillary acidic protein, and tau in a regional epilepsy cohort: High plasma levels are rare but related to seizures
- 2023
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In: Epilepsia. - 0013-9580. ; 64:10, s. 2690-2700
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Journal article (peer-reviewed)abstract
- Objective: Higher levels of biochemical blood markers of brain injury have been described immediately after tonic-clonic seizures and in drug-resistant epilepsy, but the levels of such markers in epilepsy in general have not been well characterized. We analyzed neurofilament light (NfL), glial fibrillary acidic protein (GFAP), and tau in a regional hospital-based epilepsy cohort and investigated what proportion of patients have levels suggesting brain injury, and whether certain epilepsy features are associated with high levels.Methods: Biomarker levels were measured in 204 patients with an epilepsy diagnosis participating in a prospective regional biobank study, with age and sex distribution correlating closely to that of all patients seen for epilepsy in the health care region. Absolute biomarker levels were assessed between two patient groups: patients reporting seizures within the 2 months preceding inclusion and patients who did not have seizures for more than 1 year. We also assessed the proportion of patients with above-normal levels of NfL.Results: NfL and GFAP, but not tau, increased with age. Twenty-seven patients had abnormally high levels of NfL. Factors associated with such levels were recent seizures (p = .010) and epileptogenic lesion on radiology (p = .001). Levels of NfL (p = .006) and GFAP (p = .032) were significantly higher in young patients (<65 years) with seizures & LE;2 months before inclusion compared to those who reported no seizures for >1 year. NfL and GFAP correlated weakly with the number of days since last seizure (NfL: r(s) = -.228, p = .007; GFAP: r(s) = -.167, p = .048) in young patients. NfL also correlated weakly with seizure frequency in the last 2 months (r(s) = .162, p = .047).Significance: Most patients with epilepsy do not have biochemical evidence of brain injury. The association with seizures merits further study; future studies should aim for longitudinal sampling and examine whether individual variations in NfL or GFAP levels could reflect seizure activity.
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| 66. |
- Akinci, M., et al.
(author)
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Prepandemic Alzheimer Disease Biomarkers and Anxious-Depressive Symptoms During the COVID-19 Confinement in Cognitively Unimpaired Adults
- 2022
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In: NEUROLOGY. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 99:14, s. E1486-E1498
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Journal article (peer-reviewed)abstract
- Background and Objectives Increased anxious-depressive symptomatology is observed in the preclinical stage of Alzheimer disease (AD), which may accelerate disease progression. We investigated whether beta-amyloid, cortical thickness in medial temporal lobe structures, neuroinflammation, and sociodemographic factors were associated with greater anxious-depressive symptoms during the COVID-19 confinement. Methods This retrospective observational study included cognitively unimpaired older adults from the Alzheimer's and Families cohort, the majority with a family history of sporadic AD. Participants performed the Hospital Anxiety and Depression Scale (HADS) during the COVID-19 confinement. A subset had available retrospective (on average: 2.4 years before) HADS assessment, amyloid [F-18] flutemetamol PET and structural MRI scans, and CSF markers of neuroinflammation (interleukin-6 [IL-6], triggering receptor expressed on myeloid cells 2, and glial fibrillary acidic protein levels). We performed multivariable linear regression models to investigate the associations of prepandemic AD-related biomarkers and sociodemographic factors with HADS scores during the confinement. We further performed an analysis of covariance to adjust by participants' prepandemic anxiety-depression levels. Finally, we explored the role of stress and lifestyle changes (sleep patterns, eating, drinking, smoking habits, and medication use) on the tested associations and performed sex-stratified analyses. Results We included 921 (254 with AD biomarkers) participants. beta-amyloid positivity (B = 3.73; 95% CI = 1.1 to 6.36; p = 0.006), caregiving (B = 1.37; 95% CI 0.24-2.5; p = 0.018), sex (women: B = 1.95; 95% CI 1.1-2.79; p < 0.001), younger age (B = -0.12; 95% CI -0.18 to -0.052; p < 0.001), and lower education (B = -0.16; 95% CI -0.28 to -0.042; p = 0.008) were associated with greater anxious-depressive symptoms during the confinement. Considering prepandemic anxiety-depression levels, we further observed an association between lower levels of CSF IL-6 (B = -5.11; 95% CI -10.1 to -0.13; p = 0.044) and greater HADS scores. The results were independent of stress-related variables and lifestyle changes. Stratified analysis revealed that the associations were mainly driven by women. Discussion Our results link AD-related pathophysiology and neuroinflammation with greater anxious-depressive symptomatology during the COVID-19-related confinement, notably in women. AD pathophysiology may increase neuropsychiatric symptomatology in response to stressors. This association may imply a worse clinical prognosis in people at risk for AD after the pandemic and thus deserves to be considered by clinicians.
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| 67. |
- Aksnes, M., et al.
(author)
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Matrix metalloproteinases are associated with brain atrophy in cognitively unimpaired individuals
- 2023
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In: Neurobiology of Aging. - 0197-4580. ; 131, s. 11-23
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Journal article (peer-reviewed)abstract
- Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) have been linked to age-related neurodegeneration and Alzheimer's disease (AD), but their role in normal aging is poorly understood. We used linear mixed models to determine if baseline or rate of yearly change in cerebrospinal fluid (CSF) levels of MMP-2; MMP-3; MMP-10; TIMP-123 (composite of TIMP-1, TIMP-2, and TIMP-3); or TIMP-4 predicted changes in bilateral entorhinal cortex thickness, hippocampal volume, or lateral ventricle volume in cognitively unimpaired individuals. We also assessed effects on the CSF AD biomarkers amyloid-& beta;42 and phosphorylated tau181. Low baseline levels of MMP-3 predicted larger ventricle volumes and more entorhinal cortex thinning. Increased CSF MMP-2 levels over time predicted more entorhinal thinning, hippocampal atrophy, and ventricular expansion, while increased TIMP-123 over time predicted ventricular expansion. No MMP/TIMPs predicted changes in CSF AD biomarkers. Notably, we show for the first time that longitudinal increases in MMP-2 and TIMP-123 levels may predict age-associated brain atrophy. In conclusion, MMPs and TIMPs may play a role in brain atrophy in cognitively unimpaired aging. & COPY; 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 68. |
- Alagaratnam, Jasmini, et al.
(author)
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Correlation between cerebrospinal fluid and plasma neurofilament light protein in treated HIV infection: results from the COBRA study.
- 2022
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In: Journal of neurovirology. - : Springer Science and Business Media LLC. - 1538-2443 .- 1355-0284. ; 28:1, s. 54-63
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Journal article (peer-reviewed)abstract
- Cerebrospinal fluid (CSF) neurofilament light protein (NfL) is a marker of central nervous system neuro-axonal injury. A novel, ultra-sensitive assay can determine plasma NfL. In untreated people-with-HIV (PWH), CSF and plasma NfL are strongly correlated. We aimed to assess this correlation in PWH on suppressive antiretroviral treatment (ART) and lifestyle-similar HIV-negative individuals enrolled into the COmorBidity in Relation to AIDS (COBRA) study. Differences in paired CSF (sandwich ELISA, UmanDiagnostics) and plasma (Simoa digital immunoassay, Quanterix™) NfL between PWH and HIV-negative participants were tested using Wilcoxon's test; associations were assessed using Pearson's correlation. CSF and plasma NfL, standardised to Z-scores, were included as dependent variables in linear regression models to identify factors independently associated with values in PWH and HIV-negative participants. Overall, 132 PWH (all with plasma HIV RNA < 50 copies/mL) and 79 HIV-negative participants were included. Neither CSF (median 570 vs 568 pg/mL, p = 0.37) nor plasma (median 10.7 vs 9.9 pg/mL, p = 0.15) NfL differed significantly between PWH and HIV-negative participants, respectively. CSF and plasma NfL correlated moderately, with no significant difference by HIV status (PWH: rho = 0.52; HIV-negative participants: rho = 0.47, p (interaction) = 0.63). In multivariable regression analysis, higher CSF NfL Z-score was statistically significantly associated with older age and higher CSF protein, and higher plasma NfL Z-score with older age, higher serum creatinine and lower bodyweight. In conclusion, in PWH on ART, the correlation between CSF and plasma NfL is moderate and similar to that observed in lifestyle-similar HIV-negative individuals. Consideration of renal function and bodyweight may be required when utilising plasma NfL.
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| 69. |
- Alagaratnam, J., et al.
(author)
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Correlation between CSF and blood neurofilament light chain protein: a systematic review and meta-analysis
- 2021
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In: Bmj Neurology Open. - : BMJ. - 2632-6140. ; 3:1
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Journal article (peer-reviewed)abstract
- Objective To assess the overall pooled correlation coefficient estimate between cerebrospinal fluid (CSF) and blood neurofilament light (NfL) protein. Methods We searched Medline, Embase and Web of Science for published articles, from their inception to 9 July 2019, according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Studies reporting the correlation between CSF and blood NfL in humans were included. We conducted a random-effects meta-analysis to calculate the overall pooled correlation coefficient estimate, accounting for correlation technique and assay used. Heterogeneity was assessed using the I-2 statistic test. In sensitivity analyses, we calculated the pooled correlation coefficient estimate according to blood NfL assay: single-molecule array digital immunoassay (Simoa), electrochemiluminescence (ECL) assay or ELISA. Results Data were extracted from 36 articles, including 3961 paired CSF and blood NfL samples. Overall, 26/36 studies measured blood NfL using Simoa, 8/36 ECL, 1/36 ELISA and 1 study reported all three assay results. The overall meta-analysis demonstrated that the pooled correlation coefficient estimate for CSF and blood NfL was r=0.72. Heterogeneity was significant: I-2=83%, p<0.01. In sensitivity analyses, the pooled correlation coefficient was similar for studies measuring blood NfL using Simoa and ECL (r=0.69 and r=0.68, respectively) but weaker for ELISA (r=0.35). Conclusion Moderate correlations are demonstrated between CSF and blood NfL, especially when blood NfL was measured using Simoa and ECL. Given its high analytical sensitivity, Simoa is the preferred assay for measuring NfL, especially at low or physiological concentrations, and this meta-analysis supports its use as the current most advanced surrogate measure of CSF NfL. PROSPERO registration number CRD42019140469
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| 70. |
- Alagaratnam, J., et al.
(author)
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No evidence of neuronal damage as measured by neurofilament light chain in a HIV cure study utilising a kick-and-kill approach
- 2021
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In: Journal of Virus Eradication. - : Elsevier BV. - 2055-6640. ; 7:3
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Journal article (peer-reviewed)abstract
- Objective: HIV-remission strategies including kick-and-kill could induce viral transcription and immune activation in the central nervous system, potentially causing neuronal injury. We investigated the impact of kick-and-kill on plasma neurofilament light (NfL), a marker of neuro-axonal injury, in RIVER trial participants commencing antiretroviral treatment (ART) during primary infection and randomly allocated to ART-alone or kick-and-kill (ART + vaccination + vorinostat (ART + V + V)). Design: Sub-study measuring serial plasma NfL concentrations. Methods: Plasma NfL (using Simoa digital immunoassay), plasma HIV-1 RNA (using single-copy assay) and total HIV-1 DNA (using quantitative polymerase chain reaction in peripheral CD4(+) T-cells) were measured at randomisation (following >= 22 weeks ART), week 12 (on final intervention day in ART + V + V) and week 18 post randomisation. HIV-specific T-cells were quantified by intracellular cytokine staining at randomisation and week 12. Differences in plasma NfL longitudinally and by study arm were analysed using mixed models and Student's t-test. Associations with plasma NfL were assessed using linear regression and rank statistics. Results: At randomisation, 58 male participants had median age 32 years and CD4(+) count 696 cells/mu L. No significant difference in plasma NfL was seen longitudinally and by study arm, with median plasma NfL (pg/mL) in ART-only vs ART + V + V: 7.4 vs 6.4, p = 0.16 (randomisation), 8.0 vs 6.9, p = 0.22 (week 12) and 7.1 vs 6.8, p = 0.74 (week 18). Plasma NfL did not significantly correlate with plasma HIV-1 RNA and total HIV-1 DNA concentration in peripheral CD4(+) T-cells at any timepoint. While higher HIV-specific T-cell responses were seen at week 12 in ART + V + V, there were no significant correlations with plasma NfL. In multivariate analysis, higher plasma NfL was associated with older age, higher CD8(+) count and lower body mass index. Conclusions: Despite evidence of vaccine-induced HIV-specific T-cell responses, we observed no evidence of increased neuro-axonal injury using plasma NfL as a biomarker up to 18 weeks following kick-and-kill, compared with ART-only.
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