| 51. |
- Daborg, Jonny, et al.
(författare)
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Cerebrospinal fluid levels of complement proteins C3, C4 and CR1 in Alzheimer's disease.
- 2012
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Ingår i: Journal of neural transmission (Vienna, Austria : 1996). - : Springer Science and Business Media LLC. - 1435-1463 .- 0300-9564. ; 119:7, s. 789-97
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is strongly associated with loss of synapses. The complement system has been shown to be involved in synaptic elimination. Several studies point to an association between AD and the complement system. The purpose of this study was to examine the association of cerebrospinal fluid (CSF) levels of complement components 3 and 4 (C3 and C4, respectively), and complement receptor 1 (CR1) with AD in 43 patients with AD plus dementia, 42 patients with mild cognitive impairment (MCI) who progressed to AD during follow-up (MCI-AD), 42 patients with stable MCI and 44 controls. Complement levels were also applied in a multivariate model to determine if they provided any added value to the core AD biomarkers Aβ42, T-tau and P-tau. We found elevated CSF levels of C3 and C4 in AD compared with MCI without progression to AD, and elevated CSF levels of CR1 in MCI-AD and AD when these groups were merged. These results provide support for aberrant complement regulation as a part in the AD process, but the changes are not diagnostically useful.
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| 52. |
- Daborg, Jonny, et al.
(författare)
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Complement Gene Single Nucleotide Polymorphisms and Biomarker Endophenotypes of Alzheimer's Disease
- 2013
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877. ; 35:1, s. 51-57
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Tidskriftsartikel (refereegranskat)abstract
- The complement system has been implicated in both physiological synapse elimination and Alzheimer's disease (AD). Here, we investigated associations between four single nucleotide polymorphisms (SNPs) in complement genes and cerebrospinal fluid (CSF) biomarkers for AD in 452 neurochemically or neuropathologically verified AD cases and 678 cognitively normal controls. None of the SNPs associated with risk of AD but there were potential associations of rs9332739 in the C2 gene and rs4151667 in the complement factor B gene with CSF tau levels (p = 0.023) and Mini-Mental State Examination scores (p = 0.012), both of which may be considered markers of disease intensity/severity.
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| 53. |
- Damian, Marinella, et al.
(författare)
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Single-Domain Amnestic Mild Cognitive Impairment Identified by Cluster Analysis Predicts Alzheimer's Disease in the European Prospective DESCRIPA Study
- 2013
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Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 36:1-2, s. 1-19
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Tidskriftsartikel (refereegranskat)abstract
- Background/Aims: To identify prodromal Alzheimer's disease (AD) subjects using a data-driven approach to determine cognitive profiles in mild cognitive impairment (MCI). Methods: A total of 881 MCI subjects were recruited from 20 memory clinics and followed for up to 5 years. Outcome measures included cognitive variables, conversion to AD, and biomarkers (e. g. CSF, and MRI markers). Two hierarchical cluster analyses (HCA) were performed to identify clusters of subjects with distinct cognitive profiles. The first HCA included all subjects with complete cognitive data, whereas the second one selected subjects with very mild MCI (MMSE >= 28). ANOVAs and ANCOVAs were computed to examine whether the clusters differed with regard to conversion to AD, and to AD-specific biomarkers. Results: The HCAs identified 4-cluster solutions that best reflected the sample structure. One cluster (aMCIsingle) had a significantly higher conversion rate (19%), compared to subjective cognitive impairment (SCI, p < 0.0001), and non-amnestic MCI (naMCI, p = 0.012). This cluster was the only one showing a significantly different biomarker profile (A beta(42), t-tau, APOE epsilon 4, and medial temporal atrophy), compared to SCI or naMCI. Conclusion: In subjects with mild MCI, the single-domain amnestic MCI profile was associated with the highest risk of conversion, even if memory impairment did not necessarily cross specific cut-off points. A cognitive profile characterized by isolated memory deficits may be sufficient to warrant applying prevention strategies in MCI, whether or not memory performance lies below specific z-scores. This is supported by our preliminary biomarker analyses. However, further analyses with bigger samples are needed to corroborate these findings. Copyright (C) 2013 S. Karger AG, Basel
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| 54. |
- Darreh-Shori, T., et al.
(författare)
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Changes in the activity and protein levels of CSF acetylcholinesterases in relation to cognitive function of patients with mild Alzheimer's disease following chronic donepezil treatment
- 2006
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Ingår i: Journal of Neural Transmission. - : Springer Science and Business Media LLC. - 0300-9564 .- 1435-1463. ; 113:11, s. 1791-1801
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Tidskriftsartikel (refereegranskat)abstract
- Objectives. To evaluate long-term changes in acetylcholinesterase (AChE) activity in CSF and blood following donepezil treatment in relation to the concentration of donepezil and cognition in AD patients. Methods. CSF or blood (or both) samples of a total of 104 patients with mild AD were used [MMSE score 23 +/- 0.4; age 75 +/- 1 years (mean +/- SEM); n = 53 for CSF and n = 51 for plasma/red blood cell (RBC) samples]. The patients were treated with 5 or 10 mg/day donepezil and clinically followed for 2 years. The CSF and RBC AChE activities were measured by the Ellman's direct colorimetric assay. Protein levels of two variants of AChE ("read-through" AChE-R and synaptic AChE-S) were determined by an ELISA-like method. Results. The plasma donepezil concentration was dose-dependent (between 30 and 60 ng/mL in the 5-mg and 10-mg group, respectively). The CSF donepezil concentration was 10 times lower than the plasma level and showed dose- and time-dependent kinetics. The RBC AChE inhibition was moderate (19-29%). CSF AChE-S inhibition was estimated to 30-40% in the 5-mg and 45-55% in the 10-mg group. Positive correlations were observed between the CSF AChE inhibition, an increased protein level of the AChE-R variant and MMSE examination. Patients with high AChE inhibition (>= 45%) showed a stabilized MMSE test result after up to two years, while a significant decline was observed in AD patients with lower AChE inhibition (<= 30%). Conclusions. An increase in the protein level of the AChE-R variant corresponded to a high AChE inhibition in CSF and favored less cognitive deterioration.
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| 55. |
- Davidsson, P, et al.
(författare)
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Differential increase in cerebrospinal fluid-acetylcholinesterase after treatment with acetylcholinesterase inhibitors in patients with Alzheimer's disease
- 2001
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Ingår i: Neuroscience Letters. - 0304-3940. ; 300:3, s. 157-160
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Tidskriftsartikel (refereegranskat)abstract
- The clinical significance and the effects of pharmacological treatment of patients with Alzheimer's disease (AD) were evaluated by measurement of acetylcholinesterase (AChE) in the cerebrospinal fluid (CSF). CSF-AChE of AD patients was lower, not significantly, compared with controls. However, CSF-AChE was significantly increased after treatment of AD patients with AChE inhibitors (donepezil and galantamine). The increase was higher in patients treated with donezepil than in those treated with galantamine, which might be related to different mechanisms for the substances. The increase was also dose-dependent, and was especially marked in patients showing a clinical response. These data suggest that CSF biomarkers are capable not only of identifying a biochemical effect of drugs, but also of differentiating between different compounds in a dose-dependent manner.
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| 56. |
- De Meyer, Geert, et al.
(författare)
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Diagnosis-independent Alzheimer disease biomarker signature in cognitively normal elderly people.
- 2010
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Ingår i: Archives of neurology. - : American Medical Association (AMA). - 1538-3687 .- 0003-9942. ; 67:8, s. 949-56
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To identify biomarker patterns typical for Alzheimer disease (AD) in an independent, unsupervised way, without using information on the clinical diagnosis. DESIGN: Mixture modeling approach. SETTING: Alzheimer's Disease Neuroimaging Initiative database. Patients or Other PARTICIPANTS: Cognitively normal persons, patients with AD, and individuals with mild cognitive impairment. MAIN OUTCOME MEASURES: Cerebrospinal fluid-derived beta-amyloid protein 1-42, total tau protein, and phosphorylated tau(181P) protein concentrations were used as biomarkers on a clinically well-characterized data set. The outcome of the qualification analysis was validated on 2 additional data sets, 1 of which was autopsy confirmed. RESULTS: Using the US Alzheimer's Disease Neuroimaging Initiative data set, a cerebrospinal fluid beta-amyloid protein 1-42/phosphorylated tau(181P) biomarker mixture model identified 1 feature linked to AD, while the other matched the "healthy" status. The AD signature was found in 90%, 72%, and 36% of patients in the AD, mild cognitive impairment, and cognitively normal groups, respectively. The cognitively normal group with the AD signature was enriched in apolipoprotein E epsilon4 allele carriers. Results were validated on 2 other data sets. In 1 study consisting of 68 autopsy-confirmed AD cases, 64 of 68 patients (94% sensitivity) were correctly classified with the AD feature. In another data set with patients (n = 57) with mild cognitive impairment followed up for 5 years, the model showed a sensitivity of 100% in patients progressing to AD. CONCLUSIONS: The mixture modeling approach, totally independent of clinical AD diagnosis, correctly classified patients with AD. The unexpected presence of the AD signature in more than one-third of cognitively normal subjects suggests that AD pathology is active and detectable earlier than has heretofore been envisioned.
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| 57. |
- De Meyer, Geert, et al.
(författare)
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Diagnosis-Independent Alzheimer Disease Biomarker Signature in Cognitively Normal Elderly People
- 2010
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Ingår i: Archives of Neurology. - 0003-9942. ; 67:8, s. 949-956
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To identify biomarker patterns typical for Alzheimer disease (AD) in an independent, unsupervised way, without using information on the clinical diagnosis. Design: Mixture modeling approach. Setting: Alzheimer's Disease Neuroimaging Initiative database. Patients or Other Participants: Cognitively normal persons, patients with AD, and individuals with mild cognitive impairment. Main Outcome Measures: Cerebrospinal fluid derived p-amyloid protein 1-42, total tau protein, and phosphorylated tau(181p) protein concentrations were used as biomarkers on a clinically well-characterized data set. The outcome of the qualification analysis was validated on 2 additional data sets, 1 of which was autopsy confirmed. Results: Using the US Alzheimer's Disease Neuroimaging Initiative data set, a cerebrospinal fluid beta-amyloid protein 1-42/phosphorylated tau(181P) biomarker mixture model identified 1 feature linked to AD, while the other matched the "healthy" status. The AD signature was found in 90%, 72%, and 36% of patients in the AD, mild cognitive impairment, and cognitively normal groups, respectively. The cognitively normal group with the AD signature was enriched in apolipoprotein E 64 allele carriers. Results were validated on 2 other data sets. In 1 study consisting of 68 autopsy-confirmed AD cases, 64 of 68 patients (94% sensitivity) were correctly classified with the AD feature. In another. data set with patients (n=57) with mild cognitive impairment followed up for 5 years, the model showed a sensitivity of 100% in patients progressing to AD. Conclusions: The mixture modeling approach, totally independent of clinical AD diagnosis, correctly classified patients with AD. The unexpected presence of the AD signature in more than one-third of cognitively normal subjects suggests that AD pathology is active and detectable earlier than has heretofore been envisioned.
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| 58. |
- Deming, Yuetiva, et al.
(författare)
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Genome-wide association study identifies four novel loci associated with Alzheimer’s endophenotypes and disease modifiers
- 2017
-
Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 133:5, s. 839-856
-
Tidskriftsartikel (refereegranskat)abstract
- More than 20 genetic loci have been associated with risk for Alzheimer’s disease (AD), but reported genome-wide significant loci do not account for all the estimated heritability and provide little information about underlying biological mechanisms. Genetic studies using intermediate quantitative traits such as biomarkers, or endophenotypes, benefit from increased statistical power to identify variants that may not pass the stringent multiple test correction in case–control studies. Endophenotypes also contain additional information helpful for identifying variants and genes associated with other aspects of disease, such as rate of progression or onset, and provide context to interpret the results from genome-wide association studies (GWAS). We conducted GWAS of amyloid beta (Aβ42), tau, and phosphorylated tau (ptau181) levels in cerebrospinal fluid (CSF) from 3146 participants across nine studies to identify novel variants associated with AD. Five genome-wide significant loci (two novel) were associated with ptau181, including loci that have also been associated with AD risk or brain-related phenotypes. Two novel loci associated with Aβ42 near GLIS1 on 1p32.3 (β = −0.059, P = 2.08 × 10−8) and within SERPINB1 on 6p25 (β = −0.025, P = 1.72 × 10−8) were also associated with AD risk (GLIS1: OR = 1.105, P = 3.43 × 10−2), disease progression (GLIS1: β = 0.277, P = 1.92 × 10−2), and age at onset (SERPINB1: β = 0.043, P = 4.62 × 10−3). Bioinformatics indicate that the intronic SERPINB1 variant (rs316341) affects expression of SERPINB1 in various tissues, including the hippocampus, suggesting that SERPINB1 influences AD through an Aβ-associated mechanism. Analyses of known AD risk loci suggest CLU and FERMT2 may influence CSF Aβ42 (P = 0.001 and P = 0.009, respectively) and the INPP5D locus may affect ptau181 levels (P = 0.009); larger studies are necessary to verify these results. Together the findings from this study can be used to inform future AD studies.
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| 59. |
- Deming, Yuetiva, et al.
(författare)
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Sex-specific genetic predictors of Alzheimer’s disease biomarkers
- 2018
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 136:6, s. 857-872
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Tidskriftsartikel (refereegranskat)abstract
- Cerebrospinal fluid (CSF) levels of amyloid-β 42 (Aβ42) and tau have been evaluated as endophenotypes in Alzheimer’s disease (AD) genetic studies. Although there are sex differences in AD risk, sex differences have not been evaluated in genetic studies of AD endophenotypes. We performed sex-stratified and sex interaction genetic analyses of CSF biomarkers to identify sex-specific associations. Data came from a previous genome-wide association study (GWAS) of CSF Aβ42 and tau (1527 males, 1509 females). We evaluated sex interactions at previous loci, performed sex-stratified GWAS to identify sex-specific associations, and evaluated sex interactions at sex-specific GWAS loci. We then evaluated sex-specific associations between prefrontal cortex (PFC) gene expression at relevant loci and autopsy measures of plaques and tangles using data from the Religious Orders Study and Rush Memory and Aging Project. In Aβ42, we observed sex interactions at one previous and one novel locus: rs316341 within SERPINB1 (p = 0.04) and rs13115400 near LINC00290 (p = 0.002). These loci showed stronger associations among females (β = − 0.03, p = 4.25 × 10−8; β = 0.03, p = 3.97 × 10−8) than males (β = − 0.02, p = 0.009; β = 0.01, p = 0.20). Higher levels of expression of SERPINB1, SERPINB6, and SERPINB9 in PFC was associated with higher levels of amyloidosis among females (corrected p values < 0.02) but not males (p > 0.38). In total tau, we observed a sex interaction at a previous locus, rs1393060 proximal to GMNC (p = 0.004), driven by a stronger association among females (β = 0.05, p = 4.57 × 10−10) compared to males (β = 0.02, p = 0.03). There was also a sex-specific association between rs1393060 and tangle density at autopsy (pfemale = 0.047; pmale = 0.96), and higher levels of expression of two genes within this locus were associated with lower tangle density among females (OSTN p = 0.006; CLDN16 p = 0.002) but not males (p ≥ 0.32). Results suggest a female-specific role for SERPINB1 in amyloidosis and for OSTN and CLDN16 in tau pathology. Sex-specific genetic analyses may improve understanding of AD’s genetic architecture.
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| 60. |
- Drouin-Ouellet, Janelle, et al.
(författare)
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REST suppression mediates neural conversion of adult human fibroblasts via microRNA-dependent and -independent pathways
- 2017
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Ingår i: EMBO Molecular Medicine. - : EMBO. - 1757-4684 .- 1757-4676. ; 9:8, s. 1117-1131
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Tidskriftsartikel (refereegranskat)abstract
- Direct conversion of human fibroblasts into mature and functional neurons, termed induced neurons (iNs), was achieved for the first time 6 years ago. This technology offers a promising shortcut for obtaining patient- and disease-specific neurons for disease modeling, drug screening, and other biomedical applications. However, fibroblasts from adult donors do not reprogram as easily as fetal donors, and no current reprogramming approach is sufficiently efficient to allow the use of this technology using patient-derived material for large-scale applications. Here, we investigate the difference in reprogramming requirements between fetal and adult human fibroblasts and identify REST as a major reprogramming barrier in adult fibroblasts. Via functional experiments where we overexpress and knockdown the REST-controlled neuron-specific microRNAs miR-9 and miR-124, we show that the effect of REST inhibition is only partially mediated via microRNA up-regulation. Transcriptional analysis confirmed that REST knockdown activates an overlapping subset of neuronal genes as microRNA overexpression and also a distinct set of neuronal genes that are not activated via microRNA overexpression. Based on this, we developed an optimized one-step method to efficiently reprogram dermal fibroblasts from elderly individuals using a single-vector system and demonstrate that it is possible to obtain iNs of high yield and purity from aged individuals with a range of familial and sporadic neurodegenerative disorders including Parkinson's, Huntington's, as well as Alzheimer's disease.
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