| 1. |
- Kadir, Ahmadul, et al.
(author)
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Effect of phenserine treatment on brain functional activity and amyloid in Alzheimer's disease.
- 2008
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In: Annals of neurology. - : Wiley. - 1531-8249 .- 0364-5134. ; 63:5, s. 621-31
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Journal article (peer-reviewed)abstract
- OBJECTIVE: The effects of (-)-phenserine (phenserine) and placebo/donepezil treatment on regional cerebral metabolic rate for glucose (rCMRglc) and brain amyloid load were investigated by positron emission tomography in 20 patients with mild Alzheimer's disease in relation to cerebrospinal fluid (CSF) and plasma biomarkers, and cognitive function. METHODS: The first 3 months of the study was a randomized, double-blind, placebo-controlled phase, during which 10 patients received phenserine (30 mg/day) and 10 patients the placebo. Three to 6 months was an open-label extension phase, during which the placebo group received donepezil (5 mg/day) and the phenserine group remained on phenserine. After 6 months, all patients received phenserine treatment up to 12 months. The patients underwent positron emission tomography examinations to measure rCMRglc (8F-FDG) and amyloid load (11C-PIB) at baseline and after 3 and 6 months of the treatment. Neuropsychological and biomarker data were collected at the three times of positron emission tomography imaging. RESULTS: Statistically significant effects on a composite neuropsychological test score were observed in the phenserine-treated group compared with the placebo and donepezil group at 3 and 6 months, respectively. Values of rCMRglc were significantly increased in several cortical regions after 3 months of phenserine treatment, compared with baseline, and correlated positively with cognitive function and CSF beta-amyloid 40 (Abeta40). Cortical Pittsburgh Compound B retention correlated negatively with CSF Abeta40 levels and the ratio Abeta/beta-secretase-cleaved amyloid precursor protein. In CSF, Abeta40 correlated positively with the attention domain of cognition. INTERPRETATION: Phenserine treatment was associated with an improvement in cognition and an increase in rCMRglc.
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| 2. |
- Andreasson, Ulf, 1968, et al.
(author)
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A Practical Guide to Immunoassay Method Validation.
- 2015
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In: Frontiers in neurology. - : Frontiers Media SA. - 1664-2295. ; 6
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Journal article (peer-reviewed)abstract
- Biochemical markers have a central position in the diagnosis and management of patients in clinical medicine, and also in clinical research and drug development, also for brain disorders, such as Alzheimer's disease. The enzyme-linked immunosorbent assay (ELISA) is frequently used for measurement of low-abundance biomarkers. However, the quality of ELISA methods varies, which may introduce both systematic and random errors. This urges the need for more rigorous control of assay performance, regardless of its use in a research setting, in clinical routine, or drug development. The aim of a method validation is to present objective evidence that a method fulfills the requirements for its intended use. Although much has been published on which parameters to investigate in a method validation, less is available on a detailed level on how to perform the corresponding experiments. To remedy this, standard operating procedures (SOPs) with step-by-step instructions for a number of different validation parameters is included in the present work together with a validation report template, which allow for a well-ordered presentation of the results. Even though the SOPs were developed with the intended use for immunochemical methods and to be used for multicenter evaluations, most of them are generic and can be used for other technologies as well.
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| 3. |
- Bloniecki, Victor, et al.
(author)
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Are neuropsychiatric symptoms in dementia linked to CSF biomarkers of synaptic and axonal degeneration?
- 2020
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In: Alzheimer's Research & Therapy. - : BioMed Central. - 1758-9193. ; 12:1
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Journal article (peer-reviewed)abstract
- BACKGROUND: The underlying disease mechanism of neuropsychiatric symptoms (NPS) in dementia remains unclear. Cerebrospinal fluid (CSF) biomarkers for synaptic and axonal degeneration may provide novel neuropathological information for their occurrence. The aim was to investigate the relationship between NPS and CSF biomarkers for synaptic (neurogranin [Ng], growth-associated protein 43 [GAP-43]) and axonal (neurofilament light [NFL]) injury in patients with dementia.METHODS: A total of 151 patients (mean age ± SD, 73.5 ± 11.0, females n = 92 [61%]) were included, of which 64 had Alzheimer's disease (AD) (34 with high NPS, i.e., Neuropsychiatric Inventory (NPI) score > 10 and 30 with low levels of NPS) and 18 were diagnosed with vascular dementia (VaD), 27 with mixed dementia (MIX), 12 with mild cognitive impairment (MCI), and 30 with subjective cognitive impairment (SCI). NPS were primarily assessed using the NPI. CSF samples were analyzed using enzyme-linked immunosorbent assays (ELISAs) for T-tau, P-tau, Aβ1-42, Ng, NFL, and GAP-43.RESULTS: No significant differences were seen in the CSF levels of Ng, GAP-43, and NFL between AD patients with high vs low levels of NPS (but almost significantly decreased for Ng in AD patients < 70 years with high NPS, p = 0.06). No significant associations between NPS and CSF biomarkers were seen in AD patients. In VaD (n = 17), negative correlations were found between GAP-43, Ng, NFL, and NPS.CONCLUSION: Our results could suggest that low levels of Ng may be associated with higher severity of NPS early in the AD continuum (age < 70). Furthermore, our data may indicate a potential relationship between the presence of NPS and synaptic as well as axonal degeneration in the setting of VaD pathology.
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| 4. |
- Daniilidou, Makrina, et al.
(author)
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Alzheimer's disease biomarker profiling in a memory clinic cohort without common comorbidities.
- 2023
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In: Brain communications. - 2632-1297. ; 5:5
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Journal article (peer-reviewed)abstract
- Alzheimer's disease is a multifactorial disorder with large heterogeneity. Comorbidities such as hypertension, hypercholesterolaemia and diabetes are known contributors to disease progression. However, less is known about their mechanistic contribution to Alzheimer's pathology and neurodegeneration. The aim of this study was to investigate the relationship of several biomarkers related to risk mechanisms in Alzheimer's disease with the well-established Alzheimer's disease markers in a memory clinic population without common comorbidities. We investigated 13 molecular markers representing key mechanisms underlying Alzheimer's disease pathogenesis in CSF from memory clinic patients without diagnosed hypertension, hypercholesterolaemia or diabetes nor other neurodegenerative disorders. An analysis of covariance was used to compare biomarker levels between clinical groups. Associations were analysed by linear regression. Two-step cluster analysis was used to determine patient clusters. Two key markers were analysed by immunofluorescence staining in the hippocampus of non-demented control and Alzheimer's disease individuals. CSF samples from a total of 90 participants were included in this study: 30 from patients with subjective cognitive decline (age 62.4 ± 4.38, female 60%), 30 with mild cognitive impairment (age 65.6 ± 7.48, female 50%) and 30 with Alzheimer's disease (age 68.2 ± 7.86, female 50%). Angiotensinogen, thioredoxin-1 and interleukin-15 had the most prominent associations with Alzheimer's disease pathology, synaptic and axonal damage markers. Synaptosomal-associated protein 25kDa and neurofilament light chain were increased in mild cognitive impairment and Alzheimer's disease patients. Grouping biomarkers by biological function showed that inflammatory and survival components were associated with Alzheimer's disease pathology, synaptic dysfunction and axonal damage. Moreover, a vascular/metabolic component was associated with synaptic dysfunction. In the data-driven analysis, two patient clusters were identified: Cluster 1 had increased CSF markers of oxidative stress, vascular pathology and neuroinflammation and was characterized by elevated synaptic and axonal damage, compared with Cluster 2. Clinical groups were evenly distributed between the clusters. An analysis of post-mortem hippocampal tissue showed that compared with non-demented controls, angiotensinogen staining was higher in Alzheimer's disease and co-localized with phosphorylated-tau. The identification of biomarker-driven endophenotypes in cognitive disorder patients further highlights the biological heterogeneity of Alzheimer's disease and the importance of tailored prevention and treatment strategies.
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| 5. |
- Herukka, Sanna-Kaisa, et al.
(author)
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Recommendations for cerebrospinal fluid Alzheimer's disease biomarkers in the diagnostic evaluation of mild cognitive impairment.
- 2017
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In: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 13:3, s. 285-295
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Journal article (peer-reviewed)abstract
- This article presents recommendations, based on the Grading of Recommendations, Assessment, Development, and Evaluation method, for the clinical application of cerebrospinal fluid (CSF) amyloid-β1-42, tau, and phosphorylated tau in the diagnostic evaluation of patients with mild cognitive impairment (MCI). The recommendations were developed by a multidisciplinary working group and based on the available evidence and consensus from focused group discussions for 1) prediction of clinical progression to Alzheimer's disease (AD) dementia, 2) cost-effectiveness, 3) interpretation of results, and 4) patient counseling. The working group recommended using CSF AD biomarkers in the diagnostic workup of MCI patients, after prebiomarker counseling, as an add-on to clinical evaluation to predict functional decline or conversion to AD dementia and to guide disease management. Because of insufficient evidence, it was uncertain whether CSF AD biomarkers outperform imaging biomarkers. Furthermore, the working group provided recommendations for interpretation of ambiguous CSF biomarker results and for pre- and post-biomarker counseling.
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| 6. |
- Latorre-Leal, María, et al.
(author)
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CYP46A1-mediated cholesterol turnover induces sex-specific changes in cognition and counteracts memory loss in ovariectomized mice
- 2024
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In: Science advances. - 2375-2548. ; 10:4
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Journal article (peer-reviewed)abstract
- The brain-specific enzyme CYP46A1 controls cholesterol turnover by converting cholesterol into 24S-hydroxycholesterol (24OH). Dysregulation of brain cholesterol turnover and reduced CYP46A1 levels are observed in Alzheimer's disease (AD). In this study, we report that CYP46A1 overexpression in aged female mice leads to enhanced estrogen signaling in the hippocampus and improved cognitive functions. In contrast, age-matched CYP46A1 overexpressing males show anxiety-like behavior, worsened memory, and elevated levels of 5α-dihydrotestosterone in the hippocampus. We report that, in neurons, 24OH contributes to these divergent effects by activating sex hormone signaling, including estrogen receptors. CYP46A1 overexpression in female mice protects from memory impairments induced by ovariectomy while having no effects in gonadectomized males. Last, we measured cerebrospinal fluid levels of 24OH in a clinical cohort of patients with AD and found that 24OH negatively correlates with neurodegeneration markers only in women. We suggest that CYP46A1 activation is a valuable pharmacological target for enhancing estrogen signaling in women at risk of developing neurodegenerative diseases.
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| 7. |
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| 8. |
- Lewczuk, Piotr, et al.
(author)
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Cerebrospinal fluid and blood biomarkers for neurodegenerative dementias: An update of the Consensus of the Task Force on Biological Markers in Psychiatry of the World Federation of Societies of Biological Psychiatry.
- 2018
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In: The world journal of biological psychiatry : the official journal of the World Federation of Societies of Biological Psychiatry. - : Informa UK Limited. - 1814-1412. ; 19:4, s. 244-328
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Journal article (peer-reviewed)abstract
- In the 12 years since the publication of the first Consensus Paper of the WFSBP on biomarkers of neurodegenerative dementias, enormous advancement has taken place in the field, and the Task Force takes now the opportunity to extend and update the original paper. New concepts of Alzheimer's disease (AD) and the conceptual interactions between AD and dementia due to AD were developed, resulting in two sets for diagnostic/research criteria. Procedures for pre-analytical sample handling, biobanking, analyses and post-analytical interpretation of the results were intensively studied and optimised. A global quality control project was introduced to evaluate and monitor the inter-centre variability in measurements with the goal of harmonisation of results. Contexts of use and how to approach candidate biomarkers in biological specimens other than cerebrospinal fluid (CSF), e.g. blood, were precisely defined. Important development was achieved in neuroimaging techniques, including studies comparing amyloid-β positron emission tomography results to fluid-based modalities. Similarly, development in research laboratory technologies, such as ultra-sensitive methods, raises our hopes to further improve analytical and diagnostic accuracy of classic and novel candidate biomarkers. Synergistically, advancement in clinical trials of anti-dementia therapies energises and motivates the efforts to find and optimise the most reliable early diagnostic modalities. Finally, the first studies were published addressing the potential of cost-effectiveness of the biomarkers-based diagnosis of neurodegenerative disorders.
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| 9. |
- Lleó, Alberto, et al.
(author)
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Cerebrospinal fluid biomarkers in trials for Alzheimer and Parkinson diseases.
- 2015
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In: Nature reviews. Neurology. - : Springer Science and Business Media LLC. - 1759-4766 .- 1759-4758. ; 11, s. 41-55
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Research review (peer-reviewed)abstract
- Alzheimer disease (AD) and Parkinson disease (PD) are the most common neurodegenerative disorders. For both diseases, early intervention is thought to be essential to the success of disease-modifying treatments. Cerebrospinal fluid (CSF) can reflect some of the pathophysiological changes that occur in the brain, and the number of CSF biomarkers under investigation in neurodegenerative conditions has grown rapidly in the past 20 years. In AD, CSF biomarkers are increasingly being used in clinical practice, and have been incorporated into the majority of clinical trials to demonstrate target engagement, to enrich or stratify patient groups, and to find evidence of disease modification. In PD, CSF biomarkers have not yet reached the clinic, but are being studied in patients with parkinsonism, and are being used in clinical trials either to monitor progression or to demonstrate target engagement and downstream effects of drugs. CSF biomarkers might also serve as surrogate markers of clinical benefit after a specific therapeutic intervention, although additional data are required. It is anticipated that CSF biomarkers will have an important role in trials aimed at disease modification in the near future. In this Review, we provide an overview of CSF biomarkers in AD and PD, and discuss their role in clinical trials.
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| 10. |
- Mattsson, Niklas, 1979, et al.
(author)
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CSF biomarkers and incipient Alzheimer disease in patients with mild cognitive impairment.
- 2009
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In: JAMA : the journal of the American Medical Association. - : American Medical Association (AMA). - 1538-3598 .- 0098-7484. ; 302:4, s. 385-93
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Journal article (peer-reviewed)abstract
- CONTEXT: Small single-center studies have shown that cerebrospinal fluid (CSF) biomarkers may be useful to identify incipient Alzheimer disease (AD) in patients with mild cognitive impairment (MCI), but large-scale multicenter studies have not been conducted. OBJECTIVE: To determine the diagnostic accuracy of CSF beta-amyloid(1-42) (Abeta42), total tau protein (T-tau), and tau phosphorylated at position threonine 181 (P-tau) for predicting incipient AD in patients with MCI. DESIGN, SETTING, AND PARTICIPANTS: The study had 2 parts: a cross-sectional study involving patients with AD and controls to identify cut points, followed by a prospective cohort study involving patients with MCI, conducted 1990-2007. A total of 750 individuals with MCI, 529 with AD, and 304 controls were recruited by 12 centers in Europe and the United States. Individuals with MCI were followed up for at least 2 years or until symptoms had progressed to clinical dementia. MAIN OUTCOME MEASURES: Sensitivity, specificity, positive and negative likelihood ratios (LRs) of CSF Abeta42, T-tau, and P-tau for identifying incipient AD. RESULTS: During follow-up, 271 participants with MCI were diagnosed with AD and 59 with other dementias. The Abeta42 assay in particular had considerable intersite variability. Patients who developed AD had lower median Abeta42 (356; range, 96-1075 ng/L) and higher P-tau (81; range, 15-183 ng/L) and T-tau (582; range, 83-2174 ng/L) levels than MCI patients who did not develop AD during follow-up (579; range, 121-1420 ng/L for Abeta42; 53; range, 15-163 ng/L for P-tau; and 294; range, 31-2483 ng/L for T-tau, P < .001). The area under the receiver operating characteristic curve was 0.78 (95% confidence interval [CI], 0.75-0.82) for Abeta42, 0.76 (95% CI, 0.72-0.80) for P-tau, and 0.79 (95% CI, 0.76-0.83) for T-tau. Cut-offs with sensitivity set to 85% were defined in the AD and control groups and tested in the MCI group, where the combination of Abeta42/P-tau ratio and T-tau identified incipient AD with a sensitivity of 83% (95% CI, 78%-88%), specificity 72% (95% CI, 68%-76%), positive LR, 3.0 (95% CI, 2.5-3.4), and negative LR, 0.24 (95% CI, 0.21-0.28). The positive predictive value was 62% and the negative predictive value was 88%. CONCLUSIONS: This multicenter study found that CSF Abeta42, T-tau, and P-tau identify incipient AD with good accuracy, but less accurately than reported from single-center studies. Intersite assay variability highlights a need for standardization of analytical techniques and clinical procedures.
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