| 1. |
- Landgren, Sara, 1980, et al.
(författare)
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A novel ARC gene polymorphism is associated with reduced risk of Alzheimer's disease
- 2012
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Ingår i: Journal of Neural Transmission. - : Springer Science and Business Media LLC. - 0300-9564 .- 1435-1463. ; 119:7, s. 833-842
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is the most common neurodegenerative disease, and is clinically characterized by cognitive disturbances and the accumulation of the amyloid beta (A beta) peptides in plaques in the brain. Recent studies have shown the links between AD and the immediate-early gene Arc (activity-regulated cytoskeleton-associated protein), involved in synaptic plasticity and memory consolidation. For example, AD mouse models show a decreased expression of Arc mRNA in the brain. In additional, acute A beta application to brain slices leads to a widespread ARC protein diffusion, unlike the normal defined localization to synapses. In this study, we investigated genetic variation in human ARC and the risk of developing AD. To this end, we genotyped 713 subjects diagnosed with AD and 841 controls without dementia. ARC was sequenced in a group of healthy individuals, and seven previously known SNPs and three novel SNPs were identified. Two of the newly found SNPs were intronic and one, +2852(G/A), was located in the 3'UTR. Three tag SNPs were selected, including the novel SNP +2852(G/A), to relate to risk of AD, Mini Mental State Examination (MMSE) scores and cerebrospinal fluid (CSF) biomarker levels of total tau (T-tau), hyperphosphorylated tau181 (P-tau(181)) and A beta(1-42). The AA genotype of the newly found 3'-UTR SNP +2852(A/G), was associated with a decreased risk of AD (p (c) = 0.005; OR = 0.74; 95 % CI: 0.61-0.89). No associations of single SNPs or haplotypes with MMSE score or CSF biomarkers were found. Here we report a novel ARC SNP associated with a reduced risk of developing AD. To our knowledge, this is the first study associating a gene variant of ARC with any disease. The location of the SNP within the 3'UTR indicates that dendritic targeting of ARC mRNA could be involved in the molecular mechanisms underlying this protective function. However, further investigation of the importance of this SNP for ARC function, ARC processing and the pathology of AD is needed.
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| 2. |
- Blennow, Kaj, 1958, et al.
(författare)
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Longitudinal stability of CSF biomarkers in Alzheimer's disease
- 2007
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 419:1, s. 18-22
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Tidskriftsartikel (refereegranskat)abstract
- Biomarker levels in cerebrospinal fluid (CSF) may serve as surrogate markers for treatment efficacy in clinical trials of disease-modifying drugs against Alzheimer's disease (AD). A prerequisite, however, is that the marker is sufficiently stable over time in individual patients. Here, we tested the stability of the three established CSF biomarkers for AD, total tau (T-tau), tau phosphorylated at threonine 181 (P-tau181) and the 42 amino acid isoform of β-amyloid (Aβ42), over 6 months in a cohort of AD patients on stable treatment with acetylcholinesterase (AChE) inhibitors. Fifty-three patients completed the study, 29 men and 24 women, mean age (±S.D.) 76.1 ± 7.9 years. Mean levels of CSF biomarkers were very stable between baseline and endpoint, with coefficients of variation (CVs) of 4.4–6.1%. Intra-individual biomarker levels at baseline and endpoint were also highly correlated with Pearson r-values above 0.95 (p < 0.0001), for all three markers. We conclude that T-tau, P-tau and Aβ42 concentrations in CSF are remarkably stable over a 6-month period in individual AD patients. This suggest that these biomarkers may have a potential to identify and monitor very minor biochemical changes induced by treatment, and thus support their possible usefulness as surrogate markers in clinical trials with drug candidates with disease-modifying potential, such as secretase inhibitors, Aβ immunotherapy and tau phosphorylation inhibitors.
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| 3. |
- Duits, Flora H., et al.
(författare)
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The cerebrospinal fluid "Alzheimer profile": Easily said, but what does it mean?
- 2014
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Ingår i: Alzheimer's & Dementia. - : Elsevier. - 1552-5260 .- 1552-5279. ; 10:6, s. 713-723
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Tidskriftsartikel (refereegranskat)abstract
- Background: We aimed to identify the most useful definition of the "cerebrospinal fluid Alzheimer profile," based on amyloid-beta(1-42) (A beta(42)), total tau, and phosphorylated tau (p-tau), for diagnosis and prognosis of Alzheimers disease (AD). Methods: We constructed eight Alzheimer profiles with previously published combinations, including regression formulas and simple ratios. We compared their diagnostic accuracy and ability to predict dementia due to AD in 1385 patients from the Amsterdam Dementia Cohort. Results were validated in an independent cohort (n = 1442). Results: Combinations outperformed individual biomarkers. Based on the sensitivity of the best performing regression formulas, cutoffs were chosen at 0.52 for the tau/A beta(42) ratio and 0.08 for the p-tau/A beta(42) ratio. Ratios performed similar to formulas (sensitivity, 91%-93%; specificity, 81%-84%). The same combinations best predicted cognitive decline in mild cognitive impairment patients. Validation confirmed these results, especially regarding the tau/A beta(42) ratio. Conclusions: A tau/A beta(42) ratio of greater than0.52 constitutes a robust cerebrospinal fluid Alzheimer profile. We recommend using this ratio to combine biomarkers.
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| 4. |
- Blennow, Kaj, 1958, et al.
(författare)
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No association between the alpha2-macroglobulin (A2M) deletion and Alzheimer's disease, and no change in A2M mRNA, protein, or protein expression.
- 2000
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Ingår i: Journal of neural transmission (Vienna, Austria : 1996). - : Springer Science and Business Media LLC. - 0300-9564 .- 1435-1463. ; 107:8-9, s. 1065-79
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Tidskriftsartikel (refereegranskat)abstract
- A polymorphism consisting of a deletion near the 5' splice site of exon 18 on the alpha2-macroglobulin (A2M) gene (A2M-2) has been suggested to be associated with Alzheimer's disease (AD) in family-based studies. We studied the A2M-2 allele together with the ApoE alleles in a large series on patients with AD (n = 449) and age-matched controls (n = 349). Neuropathologically confirmed diagnoses were available in 199 cases (94 AD and 107 control cases). We found no increase in A2M-2 genotype or allele frequencies in AD (27.5% and 14.6%) versus controls (26.4% and 14.9%). In contrast, a marked increase (p < 0.0001) in ApoE epsilon4 genotype or allele frequencies was found in AD (66.6% and 41.2%) as compared with controls (29.8% and 16.5%), suggesting sufficient statistical power in our sample. No relation was found between the A2M-2 and the ApoE epsilon4 allele. No change in A2M exon 17-18 mRNA size or sequence or A2M protein size was found in cases carrying the A2M-2 deletion, suggesting that there is no biological consequences of the A2M intronic deletion. No change in A2M protein level in cerebrospinal fluid was found in AD, suggesting that the A2M-2 allele does not effect the A2M protein expression in the brain. The lack of an association between the A2M-2 allele and AD in the present study, and the lack of abnormalities in the A2M mRNA or protein suggest that the A2M-2 allele is not associated with AD.
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| 5. |
- Hölttä, Mikko, et al.
(författare)
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Evaluating amyloid-β oligomers in cerebrospinal fluid as a biomarker for Alzheimer's disease.
- 2013
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Ingår i: PloS one. - San Francisco, CA, United States : Public Library of Science (PLoS). - 1932-6203. ; 8:6
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Tidskriftsartikel (refereegranskat)abstract
- The current study evaluated amyloid-β oligomers (Aβo) in cerebrospinal fluid as a clinical biomarker for Alzheimer's disease (AD). We developed a highly sensitive Aβo ELISA using the same N-terminal monoclonal antibody (82E1) for capture and detection. CSF samples from patients with AD, mild cognitive impairment (MCI), and healthy controls were examined. The assay was specific for oligomerized Aβ with a lower limit of quantification of 200 fg/ml, and the assay signal showed a tight correlation with synthetic Aβo levels. Three clinical materials of well characterized AD patients (n=199) and cognitively healthy controls (n=148) from different clinical centers were included, together with a clinical material of patients with MCI (n=165). Aβo levels were elevated in the all three AD-control comparisons although with a large overlap and a separation from controls that was far from complete. Patients with MCI who later converted to AD had increased Aβo levels on a group level but several samples had undetectable levels. These results indicate that presence of high or measurable Aβo levels in CSF is clearly associated with AD, but the overlap is too large for the test to have any diagnostic potential on its own.
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| 6. |
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| 7. |
- Mattsson, Niklas, 1979, et al.
(författare)
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CSF biomarkers and incipient Alzheimer disease in patients with mild cognitive impairment.
- 2009
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Ingår i: 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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Tidskriftsartikel (refereegranskat)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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| 8. |
- Olsson, Bob, 1969, et al.
(författare)
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Microglial markers are elevated in the prodromal phase of Alzheimer's disease and vascular dementia.
- 2013
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Ingår i: Journal of Alzheimer's disease : JAD. - 1875-8908 .- 1387-2877. ; 33:1, s. 45-53
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Tidskriftsartikel (refereegranskat)abstract
- Microglia manage immunosurveillance and mediate inflammation, both suggested to be important in Alzheimer's disease (AD). The aim of this study was to investigate if microglial markers could differentiate, firstly between AD and controls, and secondly between stable mild cognitive impairment (MCI) and those progressing to AD and vascular dementia (VaD). Furthermore, we investigated if these markers were sufficiently stable to be used in clinical trials. We quantified YKL-40 and sCD14 in cerebrospinal fluid (CSF) from 96 AD patients, 65 healthy controls, and 170 patients with MCI from baseline and over 5.7 years. For the stability analysis, two CSF samples were collected from 52 AD patients with a six-month interval in between. YKL-40, but not sCD14, was significantly elevated in AD compared with healthy controls (p = 0.003). Furthermore, YKL-40 and sCD14 were increased in MCI patients who converted to VaD (p = 0.029 and p = 0.008), but not to AD according to NINCDS-ADRDA. However, when stratified according to CSF levels of tau and Aβ42, YKL-40 was elevated in those with an AD-indicative profile compared with stable MCI with a normal profile (p = 0.037). In addition, YKL-40 and sCD14 were very stable in AD patients with good correlation between time-points (r = 0.94, p = 3.4 × 10-25; r = 0.77, p = 2.0 × 10-11) and the cortical damage marker T-tau. Thus, microglial markers are stable and may be used as safety markers for monitoring CNS inflammation and microglia activation in clinical trials. Moreover, YKL-40 differentiates between AD and controls and between stable MCI to AD and those that convert to AD and VaD.
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| 9. |
- Olsson, Bob, 1969, et al.
(författare)
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Cerebrospinal Fluid Levels of Heart Fatty Acid Binding Protein are Elevated Prodromally in Alzheimer's Disease and Vascular Dementia
- 2013
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 34:3, s. 673-679
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Tidskriftsartikel (refereegranskat)abstract
- Heart fatty acid binding protein (HFABP) is expressed in the brain and is elevated in cerebrospinal fluid (CSF) from patients with several forms of neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease with dementia, Lewy body dementia, vascular dementia (VaD), and Creutzfeldt-Jakob disease. However, whether HFABP in CSF is a stable biomarker or if it can help predict conversion from mild cognitive impairment (MCI) to AD or VaD has not been well studied. To address the role of HFABP in neurodegeneration, we analyzed CSF levels of HFABP in 96 AD patients and 65 controls and also in 170 patients with MCI with an average follow up time of 5.7 years. For the stability analysis, two CSF samples were collected from 52 AD patients with a six month interval in between. HFABP levels in CSF were very stable over the six month period (r = 0.93, p < 0.001). Furthermore, the CSF levels of HFABP were significantly elevated in AD compared with controls after adjustments for age and gender (p < 0.001). They were also elevated in the patients with MCI that subsequently converted to AD or VaD compared with those that remained stable (p < 0.001 and p < 0.05, respectively). However, ROC curve analysis showed that HFABP had lesser predictive value in determining conversion from MCI to AD and VaD than A beta(42), t-tau, and p-tau. In conclusion, HFABP seems to be a stable CSF biomarker that reflects neuronal cell death in several neurodegenerative disorders, including early stages of AD and VaD.
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| 10. |
- Andersson, Carl-Henrik, et al.
(författare)
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A Genetic Variant of the Sortilin 1 Gene isAssociated with Reduced Risk ofAlzheimer's Disease
- 2016
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 53:4, s. 1353-1363
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's disease (AD) is a neurodegenerative disorder represented by the accumulation of intracellular tau protein and extracellular deposits of amyloid-β (Aβ) in the brain. The gene sortilin 1 (SORT1) has previously been associated with cardiovascular disease in gene association studies. It has also been proposed to be involved in AD pathogenesis through facilitating Aβ clearance by binding apoE/Aβ complexes prior to cellular uptake. However, the neuropathological role of SORT1 in AD is not fully understood. To evaluate the associations between gene variants of SORT1 and risk of AD, we performed genetic analyses in a Swedish case-control cohort. Ten single nucleotide polymorphisms (SNPs), covering the whole SORT1 gene, were selected and genotyped in 620 AD patients and 1107 controls. The SNP rs17646665, located in a non-coding region of the SORT1 gene, remained significantly associated with decreased risk of AD after multiple testing (pc=0.0061). In addition, other SNPs were found to be nominally associated with risk of AD, as well as altered cognitive function and the CSF biomarker Aβ42, but these associations did not survive correction for multiple testing. The fact that SORT1 has been strongly associated with risk of cardiovascular disease is intriguing as cardiovascular disease is also regarded as a risk factor for AD. Finally, increased knowledge about SORT1 function has a potential to increase our understanding of APOE, the strongest risk factor for AD.
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