| 1. |
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| 2. |
- 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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| 3. |
- Gao, Carol Man, et al.
(författare)
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Aβ40 oligomers identified as a potential biomarker for the diagnosis of Alzheimer's disease.
- 2010
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 5:12
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Tidskriftsartikel (refereegranskat)abstract
- Alzheimer's Disease (AD) is the most prevalent form of dementia worldwide, yet the development of therapeutics has been hampered by the absence of suitable biomarkers to diagnose the disease in its early stages prior to the formation of amyloid plaques and the occurrence of irreversible neuronal damage. Since oligomeric Aβ species have been implicated in the pathophysiology of AD, we reasoned that they may correlate with the onset of disease. As such, we have developed a novel misfolded protein assay for the detection of soluble oligomers composed of Aβ x-40 and x-42 peptide (hereafter Aβ40 and Aβ42) from cerebrospinal fluid (CSF). Preliminary validation of this assay with 36 clinical samples demonstrated the presence of aggregated Aβ40 in the CSF of AD patients. Together with measurements of total Aβ42, diagnostic sensitivity and specificity greater than 95% and 90%, respectively, were achieved. Although larger sample populations will be needed to confirm this diagnostic sensitivity, our studies demonstrate a sensitive method of detecting circulating Aβ40 oligomers from AD CSF and suggest that these oligomers could be a powerful new biomarker for the early detection of AD.
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| 4. |
- Hansson, Oskar, et al.
(författare)
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Evaluation of plasma Abeta(40) and Abeta(42) as predictors of conversion to Alzheimer's disease in patients with mild cognitive impairment.
- 2010
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Ingår i: Neurobiology of aging. - : Elsevier BV. - 1558-1497 .- 0197-4580. ; 31:3, s. 357-67
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Tidskriftsartikel (refereegranskat)abstract
- Numerous studies have shown a marked decrease of beta-amyloid(42) (Abeta(42)) in the cerebrospinal fluid (CSF) of patients with incipient Alzheimer's disease (AD). However, studies on Abeta in plasma are contradictory, and show very marginal differences between patients and controls. Here, we analyzed plasma samples using a new multiplex immunoassay for simultaneous analysis of Abeta(1-40), Abeta(n-40), Abeta(1-42), and Abeta(n-42). The plasma samples were obtained at baseline from two independent cohorts of patients with mild cognitive impairment (MCI) and age-matched controls. In the first cohort, 41% of the 117 MCI cases converted to AD during a clinical follow-up period of 4-7 years. In the second cohort, 14% of the 110 MCI subjects developed AD during a clinical follow-up period of 2-4 years. None of the plasma Abeta isoforms differed between MCI patients that subsequently developed AD and healthy controls or stable MCI patients. The Cox proportional hazards model did not reveal any differences in the probability of progression from MCI to AD related to plasma Abeta levels. In contrast, low levels of Abeta(1-42) in CSF were strongly associated with increased risk of future AD. The absence of a change in plasma Abeta in incipient AD, despite the marked change in CSF, may be explained by the lack of a correlation between the levels of Abeta(1-42) in CSF and plasma. In conclusion, the results show that CSF biomarkers are better predictors of progression to AD than plasma Abeta isoforms.
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| 5. |
- Hertze, Joakim, et al.
(författare)
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Evaluation of CSF Biomarkers as Predictors of Alzheimer's Disease: A Clinical Follow-Up Study of 4.7 Years.
- 2010
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Ingår i: Journal of Alzheimer's disease : JAD. - 1875-8908. ; 21, s. 1119-1128
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we determined the diagnostic accuracy of cerebrospinal fluid (CSF) biomarkers to predict development of Alzheimer's disease (AD) within five years in patients with mild cognitive impairment (MCI). To do so, the levels of tau, phosphorylated tau, Abeta42, Abeta40, Abeta38, sAbetaPPalpha, and sAbetaPPbeta were analyzed in 327 CSF samples obtained at baseline from patients with AD (n= 94), MCI (n= 166), depressive disorder (n= 29), and cognitively healthy controls (n= 38). In the cohort with MCI at baseline, 33% subsequently developed AD and 16% developed other types of dementia; however, 51% were still cognitively stable after a follow-up of 4.7 years (range 3.0-7.4). Optimal cut-offs for each biomarker or combinations of biomarkers were defined in the AD, control, and depressive disorder groups. Several combinations resulted in sensitivity and specificity levels > 85% for differentiation of AD from controls and depressive disorder. Using the previously established cut-offs, a combination of Abeta42 and tau could predict future development of AD in MCI patients with a sensitivity of 88%, specificity 82%, positive predictive value 71%, and negative predictive value 94%. MCI patients with both low Abeta42 and high tau levels had a substantially increased risk of developing AD (OR 20; 95% CI 6-58), even after adjustment for confounding factors. Ultimately, CSF biomarkers can stratify MCI patients into those with very low or high risk for future development of AD. However, the specificities and positive predictive values are still too low to be able to diagnose AD before the patients fulfill the clinical criteria.
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| 6. |
- Mattsson, Niklas, 1979, et al.
(författare)
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Converging Pathways of Chromogranin and Amyloid Metabolism in the Brain
- 2010
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 20:4, s. 1039-1048
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Tidskriftsartikel (refereegranskat)abstract
- Much is unknown regarding the regulation of Alzheimer-related amyloid-beta protein precursor (A beta PP)-processing in the human central nervous system. It has been hypothesized that amyloidogenic A beta PP-processing preferentially occurs in the regulated secretory pathway of neurons. To test this hypothesis we looked for correlations of A beta PP-derived molecules in cerebrospinal fluid (CSF) with chromogranin (Cg) derived peptides, representing the regulated secretion. Patients with Alzheimer's disease (AD, N = 32), multiple sclerosis (MS, N = 50), and healthy controls (N = 70) were enrolled. CSF was analyzed for the amyloid peptides A beta(1-42), A beta(x-42), A beta(x-40), A beta(x-38), alpha-cleaved soluble A beta PP (sA beta PP alpha), beta-cleaved soluble A beta PP (sA beta PP beta), and peptides derived from CgB and SgII (Secretogranin-II, CgC). We investigated CSF levels of the protease BACE1, which processes A beta PP into A beta, in relation to Cg-levels. Finally, we measured Cg levels in cell media from untreated and BACE1-inhibited SH-SY5Y human neuroblastoma cells. CSF Cg levels correlated to sA beta PP and A beta peptides in AD, MS, and controls, and to CSF BACE1. Cell medium from BACE1-inhibited cells had decreased CgB levels. These results suggest that a large part of A beta PP in the human central nervous system is processed in the regulated secretory pathway of neurons.
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| 7. |
- Portelius, Erik, 1977, et al.
(författare)
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Distinct cerebrospinal fluid amyloid beta peptide signatures in sporadic and PSEN1 A431E-associated familial Alzheimer's disease.
- 2010
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Ingår i: Molecular neurodegeneration. - : Springer Science and Business Media LLC. - 1750-1326. ; 5:2
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Alzheimer's disease (AD) is associated with deposition of amyloid beta (Abeta) in the brain, which is reflected by low concentration of the Abeta1-42 peptide in the cerebrospinal fluid (CSF). There are at least 15 additional Abeta peptides in human CSF and their relative abundance pattern is thought to reflect the production and degradation of Abeta. Here, we test the hypothesis that AD is characterized by a specific CSF Abeta isoform pattern that is distinct when comparing sporadic AD (SAD) and familial AD (FAD) due to different mechanisms underlying brain amyloid pathology in the two disease groups. RESULTS: We measured Abeta isoform concentrations in CSF from 18 patients with SAD, 7 carriers of the FAD-associated presenilin 1 (PSEN1) A431E mutation, 17 healthy controls and 6 patients with depression using immunoprecipitation-mass spectrometry. Low CSF levels of Abeta1-42 and high levels of Abeta1-16 distinguished SAD patients and FAD mutation carriers from healthy controls and depressed patients. SAD and FAD were characterized by similar changes in Abeta1-42 and Abeta1-16, but FAD mutation carriers exhibited very low levels of Abeta1-37, Abeta1-38 and Abeta1-39. CONCLUSION: SAD patients and PSEN1 A431E mutation carriers are characterized by aberrant CSF Abeta isoform patterns that hold clinically relevant diagnostic information. PSEN1 A431E mutation carriers exhibit low levels of Abeta1-37, Abeta1-38 and Abeta1-39; fragments that are normally produced by gamma-secretase, suggesting that the PSEN1 A431E mutation modulates gamma-secretase cleavage site preference in a disease-promoting manner.
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| 8. |
- Stomrud, Erik, et al.
(författare)
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Correlation of longitudinal cerebrospinal fluid biomarkers with cognitive decline in healthy older adults.
- 2010
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Ingår i: Archives of neurology. - : American Medical Association (AMA). - 1538-3687 .- 0003-9942. ; 67:2, s. 217-23
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Abnormal cerebrospinal fluid (CSF) biomarker levels predict development of Alzheimer disease with good accuracy and are thought to precede cognitive deterioration. OBJECTIVE: To investigate whether changes in CSF biomarker levels over time in healthy older adults are associated with a concurrent decline in cognitive performance. DESIGN: Retrospective analysis of longitudinal CSF biomarker levels and clinical data. SETTING: A combined academic dementia disorder research center and dementia clinic. PARTICIPANTS: Thirty-seven cognitively healthy older volunteers (mean age, 73 years). MAIN OUTCOME MEASURES: Longitudinal CSF total tau protein, hyperphosphorylated tau protein 181, and beta-amyloid(1-42) protein levels and cognitive assessments at baseline and at follow-up 4 years later. RESULTS: Low levels of CSF beta-amyloid(1-42) protein at follow-up were associated with decreased delayed word recall score on the Alzheimer Disease Assessment Scale-cognitive subscale (r(s) = -0.437, P < .01) and with slower results on A Quick Test of Cognitive Speed (r(s) = -0.540, P < .001). Individuals with a decrease during the 4-year study of 15% or more in CSF beta-amyloid(1-42) protein level performed worse on the Alzheimer Disease Assessment Scale-cognitive subscale delayed word recall (z = -2.18, P < .05) and A Quick Test of Cognitive Speed (z = -2.35, P < .05) at follow-up. An increase over time of 20% or more in CSF hyperphosphorylated tau protein 181 level correlated with slower results on A Quick Test of Cognitive Speed at follow-up (z = -2.13, P < .05). Furthermore, the presence of the APOE-epsilon4 (OMIM 107741) allele was associated with a greater longitudinal decrease in CSF beta-amyloid(1-42) protein level (chi(2) = 10.47, P < .05) and with a higher CSF total tau protein level at follow-up (chi(2) = 8.83, P < .05). No correlation existed between baseline CSF biomarker levels and baseline or follow-up cognitive scores. CONCLUSIONS: In this group of healthy older adults, changes in CSF biomarker levels previously associated with Alzheimer disease correlated with a decline in cognitive functions. Changes in CSF biomarker levels may identify early neurodegenerative processes of Alzheimer disease.
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| 9. |
- Stomrud, Erik, et al.
(författare)
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Slowing of EEG correlates with CSF biomarkers and reduced cognitive speed in elderly with normal cognition over 4 years.
- 2010
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Ingår i: Neurobiology of aging. - : Elsevier BV. - 1558-1497 .- 0197-4580. ; 31:2, s. 215-23
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Tidskriftsartikel (refereegranskat)abstract
- Cerebrospinal fluid (CSF) biomarkers and quantitative EEG show particular patterns of change in Alzheimer's disease (AD) and reflect neuropathologic processes and cerebral function, respectively. The changes precede cognitive decline and should be visible already in preclinical stages. We therefore aimed to investigate their relationship in cognitively healthy individuals.
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| 10. |
- Sundelöf, Johan, et al.
(författare)
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Cystatin C Levels are Positively Correlated with both Aβ42 and Tau Levels in Cerebrospinal Fluid in Persons with Alzheimer's Disease, Mild Cognitive Impairment, and Healthy Controls
- 2010
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 21:2, s. 471-478
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Tidskriftsartikel (refereegranskat)abstract
- Cystatin C is suggested to be involved in neurodegeneration and the development of Alzheimer's disease (AD) by binding to soluble amyloid-beta (Abeta) peptides. Studies of cystatin C levels in cerebrospinal fluid (CSF) in relation to risk of AD are conflicting and relations between cystatin C, Abeta42, and tau levels in CSF in AD, mild cognitive impairment (MCI), and healthy controls are unknown. The objective of this study was to investigate cystatin C, Abeta42, and tau levels in CSF in AD, MCI, and controls. As a secondary aim, the relationships between cystatin C, Abeta42, and tau levels across disease groups were investigated. Cystatin C, Abeta42, total tau, and phosphorylated tau levels in CSF were analyzed by turbidimetry (cystatin C) and xMAP Luminex technology (Abeta and tau) in persons with AD (n=101), MCI (n=84), and healthy control subjects (n=28). Mean cystatin C levels were similar in cases of AD (5.6 mumol/L +/- 1.7), MCI (5.4 mumol/L +/- 1.48), and controls (5.6 mumol/L +/- 1.6). However, CSF cystatin C levels were strongly and positively correlated with total tau and phosphorylated tau levels (r=0.61-0.81, p< 0.0001) and Abeta42 (r=0.35-0.65, p< 0.001) independent of age, gender, and APOE genotype. Mean CSF cystatin C levels did not differ between patients with AD and MCI and healthy controls. Interestingly, cystatin C levels were positively correlated with both tau and Abeta42 levels in CSF independent of age, gender, and APOE genotype.
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