| 1. |
- Ashton, Nicholas J., et al.
(författare)
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Differential roles of Aβ42/40, p-tau231 and p-tau217 for Alzheimer's trial selection and disease monitoring.
- 2022
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Ingår i: Nature medicine. - : Springer Science and Business Media LLC. - 1546-170X .- 1078-8956. ; 28:12, s. 2555-2562
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Tidskriftsartikel (refereegranskat)abstract
- Blood biomarkers indicative of Alzheimer's disease (AD) pathology are altered in both preclinical and symptomatic stages of the disease. Distinctive biomarkers may be optimal for the identification of AD pathology or monitoring of disease progression. Blood biomarkers that correlate with changes in cognition and atrophy during the course of the disease could be used in clinical trials to identify successful interventions and thereby accelerate the development of efficient therapies. When disease-modifying treatments become approved for use, efficient blood-based biomarkers might also inform on treatment implementation and management in clinical practice. In the BioFINDER-1 cohort, plasma phosphorylated (p)-tau231 and amyloid-β42/40 ratio were more changed at lower thresholds of amyloid pathology. Longitudinally, however, only p-tau217 demonstrated marked amyloid-dependent changes over 4-6years in both preclinical and symptomatic stages of the disease, with no such changes observed in p-tau231, p-tau181, amyloid-β42/40, glial acidic fibrillary protein or neurofilament light. Only longitudinal increases of p-tau217 were also associated with clinical deterioration and brain atrophy in preclinical AD. The selective longitudinal increase of p-tau217 and its associations with cognitive decline and atrophy was confirmed in an independent cohort (Wisconsin Registry for Alzheimer's Prevention). These findings support the differential association of plasma biomarkers with disease development and strongly highlight p-tau217 as a surrogate marker of disease progression in preclinical and prodromal AD, with impact for the development of new disease-modifying treatments.
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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. |
- 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
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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 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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| 4. |
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| 5. |
- Hansson, Oskar, et al.
(författare)
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Evaluation of Plasma A beta as Predictor of Alzheimer's Disease in Older Individuals Without Dementia: A Population-Based Study
- 2012
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Ingår i: Journal of Alzheimer's Disease. - 1387-2877 .- 1875-8908. ; 28:1, s. 231-238
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Tidskriftsartikel (refereegranskat)abstract
- Amyloid-beta (A beta) pathology is a major component in the mechanisms behind Alzheimer's disease (AD). Measurement of A beta(42) in cerebrospinal fluid predicts cognitive decline in patients with mild cognitive impairment and identifies AD in patients with dementia. However, studies on A beta in plasma are contradictory. In this prospective population-based study, plasma A beta(42) and A beta(40) were measured at baseline in 730 adults aged 70 years or older and without dementia. After five years, plasma levels were analyzed again and participants were assessed for development of dementia. During follow-up, 53 individuals (7%) developed dementia of which 37 (5%) were classified as AD. No difference in baseline plasma A beta(42), A beta(40), or A beta(42)/A beta(40) ratio levels were observed between converters to dementia or AD compared to the cognitively stable individuals. However, individuals with plasma A beta(40) levels above the median level for the group at baseline had an increased risk of developing dementia and AD during the follow-up, even after adjustment for age, gender, APOE genotype, and educational level (odds ratio = 2.2, 95% confidence interval = 1.0-4.7, p < 0.05). Neither plasma A beta(42) nor the A beta(42)/A beta(40) ratio influenced the risk of developing dementia or AD. Moreover, A beta(42) and A beta(40) levels increased over the 5 years, whereas the A beta(42)/A beta(40) ratio decreased (p < 0.001). In conclusion, this study suggests that measurement of plasma A beta should not be used clinically to predict dementia or AD. However, plasma A beta(40) may possibly be regarded as a moderate risk marker comparable to other risk markers for AD such as first-degree family history of dementia.
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| 6. |
- 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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| 7. |
- 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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| 8. |
- Janelidze, Shorena, et al.
(författare)
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Head-to-head comparison of 10 plasma phospho-tau assays in prodromal Alzheimer's disease.
- 2023
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Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156 .- 0006-8950. ; 146:4, s. 1592-1601
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Tidskriftsartikel (refereegranskat)abstract
- Plasma phospho-tau (p-tau) species have emerged as the most promising blood-based biomarkers of Alzheimer's disease. Here, we performed a head-to-head comparison of p-tau181, p-tau217 and p-tau231 measured using 10 assays to detect abnormal brain amyloid-β status and predict future progression to Alzheimer's dementia. The study included 135 patients with baseline diagnosis of mild cognitive impairment (mean age 72.4 years; 60.7% women) who were followed for an average of 4.9 years. Seventy-one participants had abnormal Aβ-status (i.e., abnormal CSF Aβ42/40) at baseline; and 45 of these Aβ-positive participants progressed to Alzheimer's dementia during follow-up. P-tau concentrations were determined in baseline plasma and CSF. P-tau217 and p-tau181 were both measured using immunoassays developed by Lilly Research Laboratories (Lilly) and mass spectrometry assays developed at Washington University (WashU). P-tau217 was also analysed using Simoa immunoassay developed by Janssen Research and Development (Janss). P-tau181 was measured using Simoa immunoassay from ADxNeurosciences (ADx), Lumipulse immunoassay from Fujirebio (Fuji) and Splex immunoassay from Mesoscale Discovery (Splex). Both p-tau181 and p-tau231 were quantified using Simoa immunoassay developed at the University of Gothenburg (UGOT). We found that the mass spectrometry-based p-tau217 (p-tau217WashU) exhibited significantly better performance than all other plasma p-tau biomarkers when detecting abnormal Aβ status (AUC=0.947; pdiff<0.015) or progression to Alzheimer's dementia (AUC=0.932; pdiff<0.027). Among immunoassays, p-tau217Lilly had the highest AUCs (0.886-0.889), which was not significantly different from the AUCs of p-tau217Janss, p-tau181ADx and p-tau181WashU (AUCrange, 0.835-0.872; pdiff>0.09), but higher compared with AUC of p-tau231UGOT, p-tau181Lilly, p-tau181UGOT, p-tau181Fuji, and p-tau181Splex (AUCrange, 0.642-0.813; pdiff ≤0.029). Correlations between plasma and CSF values were strongest for p-tau217WashU (R=0.891) followed by p-tau217Lilly (R=0.755; pdiff=0.003 vs p-tau217WashU) and weak to moderate for the rest of the p-tau biomarkers (Rrange, 0.320-0.669). In conclusion, the findings suggest that among all tested plasma p-tau assays, mass spectrometry-based measures of p-tau217 perform best when identifying mild cognitive impairment patients with abnormal brain Aβ or those who will subsequently progress to Alzheimer's dementia. Several other assays (p-tau217Lilly, p-tau217Janss, p-tau181ADx, and p-tau181WashU) showed relatively high and consistent accuracy across both outcomes. The results further indicate that the highest performing assays have performance metrics that rival the gold standards of Aβ-PET and CSF. If further validated, our findings will have significant impacts in diagnosis, screening and treatment for Alzheimer's dementia in the future.
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| 9. |
- Leuzy, Antoine, et al.
(författare)
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Comparing the Clinical Utility and Diagnostic Performance of Cerebrospinal Fluid P-Tau181, P-Tau217 and P-Tau231 Assays
- 2021
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Ingår i: Neurology. - 1526-632X. ; 97:17, s. 1681-1694
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES: Phosphorylated tau (P-tau) in cerebrospinal fluid (CSF) is considered an important biomarker in Alzheimer's disease (AD) and has been incorporated in recent diagnostic criteria. Several variants exist, including P-tau at threonines 181 (P-tau181), 217 (P-tau217) and 231 (P-tau231). However, no studies have compared their diagnostic performance or association to amyloid-β (Aβ) and Tau positron emission tomography (PET). Understanding which P-tau variant to use remains an important yet answered question. We aimed to compare the diagnostic accuracy of P-tau181, P-tau217 and P-tau231 in CSF for AD and their association with Aβ and Tau-PET.METHODS: 629 subjects from the Swedish BioFINDER-2 study were included (cognitively unimpaired, n=334; Aβ-positive mild cognitive impairment, n=84; AD dementia, n=119; and non-AD disorders, n=92). In addition to P-tau181 and P-tau217 measured using assays with the same detector antibodies from Eli Lilly (P-tau181Lilly, P-tau217Lilly) and P-tau231, we also included P-tau181 measurements from two commonly used assays (Innotest and Elecsys).RESULTS: Though all P-tau variants increased across the AD continuum, P-tau217Lilly showed the greatest dynamic range (13-fold-increase vs 1.9-5.4-fold-increase for other P-tau variants for AD dementia vs non-AD). P-tau217Lilly showed stronger correlations with Aβ- and Tau-PET (P<0.0001). P-tau217Lilly exhibited higher accuracy than other P-tau variants for separating AD dementia from non-AD (AUC, 0.991vs 0.906-0.982, P<0.0001) and for identifying Aβ- (AUC, 0.951 vs 0.816-0.924, P<0.0001) and Tau-PET positivity (AUC, 0.957 vs 0.836-0.938, P<0.0001). Finally, P-tau181Lilly generally performed better than the other P-tau181 assays, (e.g., AD dementia vs non-AD, AUC, 0.976 vs 0.923, P<0.0001).DISCUSSION: CSF P-tau217Lilly seem to be more useful than other included P-tau assays in the work-up of AD. Varied results across P-tau181 assays also highlights the importance of anti-tau antibodies for biomarker performance.CLASSIFICATION OF EVIDENCE: This study provides class II evidence that phosphorylated tau at threonine 217 provides higher diagnostic accuracy for diagnosis of AD dementia than P-tau at threonine 181 or 231.
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| 10. |
- Thorsell, Annika, 1973, et al.
(författare)
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Neurogranin in cerebrospinal fluid as a marker of synaptic degeneration in Alzheimer's disease
- 2010
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Ingår i: Brain Research. - : Elsevier BV. - 1872-6240 .- 0006-8993. ; 1362, s. 13-22
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Tidskriftsartikel (refereegranskat)abstract
- Synaptic pathology occurs early in Alzheimer's disease (AD) development, and cerebrospinal fluid biomarkers for synaptic damage may be altered early in the disease process. In the present study we examined cerebrospinal fluid levels of the postsynaptic protein neurogranin in patients with mild cognitive impairment (MCI) or AD and controls. The low neurogranin level in cerebrospinal fluid required enrichment by immunoprecipitation prior to mass spectrometric identification and semi-quantitative immunoblot analysis. Relative quantification revealed a significant increase of neurogranin in the AD group compared with controls, while the MCI group was not statistically different from either controls or the AD group. The concentrations of the AD biomarkers T-tau, P-tau(181) and A beta(42) were significantly changed in the control and MCI groups compared with the AD group, but no significant differences were found between the MCI group and controls for the three biomarkers. Nevertheless, a trend towards increasing levels of neurogranin, T-tau and P-tau(181) was found in cerebrospinal fluid from MCI patients compared with controls. The elevated neurogranin levels in the MCI and AD groups might reflect synaptic degeneration. These results together suggest that cerebrospinal fluid neurogranin might be valuable together with the established AD biomarkers in the early diagnosis of AD and warrants further studies to determine the diagnostic value of neuroganin. (C) 2010 Elsevier B.V. All rights reserved.
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