| 1. |
- Allison, S. L., et al.
(författare)
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Comparison of different MRI-based morphometric estimates for defining neurodegeneration across the Alzheimer's disease continuum
- 2019
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Ingår i: NeuroImage: Clinical. - : Elsevier BV. - 2213-1582. ; 23
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Tidskriftsartikel (refereegranskat)abstract
- Background: Several neurodegeneration (N) metrics using structural MRI are used for the purpose of Alzheimer's disease (AD)-related staging, including hippocampal volume, global atrophy, and an “AD signature” composite consisting of thickness or volumetric estimates derived from regions impacted early in AD. This study sought to determine if less user-intensive estimates of global atrophy and hippocampal volume were equivalent to a thickness-based AD signature from FreeSurfer for defining N across the AD continuum (i.e., individuals who are amyloid-positive (A+)). Methods: Cognitively unimpaired (CU) late middle-aged and older adults, as well as A+ mild cognitive impairment (MCI) and A+ AD dementia individuals, with available CSF and structural MRI scan <1.5 years apart, were selected for the study (n = 325, mean age = 62). First, in a subsample of A+ AD dementia and matched biomarker-negative (i.e., A- and tau tangle pathology (T)-) CU controls (n = 40), we examined ROC characteristics and identified N cut-offs using Youden's J for neurofilament light chain protein (NfL) and each of three MRI-based measures: a thickness-based AD signature from FreeSurfer, hippocampal volume (using FIRST), and a simple estimate of global atrophy (the ratio of intracranial CSF segmented volume to brain tissue volume, using SPM12). Based on the results from the ROC analyses, we then examined the concordance between NfL N positivity and N positivity for each MRI-based metric using Cohen's Kappa in the remaining subsample of 285 individuals. Finally, in the full sample (n = 325), we examined the relationship between the four measures of N and group membership across the AD continuum using Kruskal-Wallis tests and Cliff's deltas. Results: The three MRI-based metrics and CSF NfL similarly discriminated between the A-T- CU (n = 20) and A+ AD (n = 20) groups (AUCs ≥0.885; ps < 0.001). Using the cut-off values derived from the ROCs to define N positivity, there was weak concordance between NfL and all three MRI-derived metrics of N in the subsample of 285 individuals (Cohen's Kappas ≤0.429). Finally, the three MRI-based measures of N and CSF NfL showed similar associations with AD continuum group (i.e., Kruskal-Wallis ps < 0.001), with relatively larger effect sizes noted when comparing the A-T- CU to the A+ MCI (Cliff's deltas ≥0.741) and A+ AD groups (Cliff's deltas ≥0.810) than to the A+T- CU (Cliff's deltas = 0.112–0.298) and A + T+ CU groups (Cliff's deltas = 0.212–0.731). Conclusions: These findings suggest that the three MRI-based morphometric estimates and CSF NfL similarly differentiate individuals across the AD continuum on N status. In many applications, a simple estimate of global atrophy may be preferred as an MRI marker of N across the AD continuum given its methodological robustness and ease of calculation when compared to hippocampal volume or a cortical thickness AD signature. © 2019
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| 2. |
- Bettcher, B. M., et al.
(författare)
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Cerebrospinal Fluid and Plasma Levels of Inflammation Differentially Relate to CNS Markers of Alzheimer's Disease Pathology and Neuronal Damage
- 2018
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 62:1, s. 385-397
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Tidskriftsartikel (refereegranskat)abstract
- Inflammatory markers have been shown to predict neurocognitive outcomes in aging adults; however, the degree to which peripheral markers mirror the central nervous system remains unknown. We investigated the association between plasma and cerebrospinal fluid (CSF) markers of inflammation, and explored whether these markers independently predict CSF indicators of Alzheimer's disease (AD) pathology or neuronal damage. Plasma and CSF samples were analyzed for inflammatory markers in a cohort of asymptomatic older adults (n = 173). CSF samples were analyzed for markers of AD pathology (A beta(42), phosphorylated tau [p-tau], sA beta PP beta) or neuronal damage (total tau; neurofilament light chain) (n = 147). Separate linear models for each analyte were conducted with CSF and plasma levels entered simultaneously as predictors and markers of AD pathology or neuronal damage as outcome measures. Strong associations were noted between CSF and plasma MIP-1 beta levels, and modest associations were observed for remaining analytes. With respect to AD pathology, higher levels of plasma and CSF IL-8, CSF MIP-1 beta, and CSF IP-10 were associated with higher levels of p-tau. Higher levels of CSF IL-8 were associated with higher levels of CSF A beta(42). Higher CSF sA beta PP beta levels were associated with higher plasma markers only (IL-8; MCP-1). In terms of neuronal injury, higher levels of plasma and CSF IL-8, CSF IP-10, and CSF MIP-1 beta were associated with higher levels of CSF total tau. Exploratory analyses indicated that CSF A beta(42) modifies the relationship between plasma inflammatory levels and CSF tau levels. Results suggest that both plasma and CSF inflammatory markers independently relay integral information about AD pathology and neuronal damage.
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| 3. |
- Bruno, D., et al.
(författare)
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A comparison of diagnostic performance of word-list and story recall tests for biomarker-determined Alzheimer's disease
- 2023
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Ingår i: Journal of Clinical and Experimental Neuropsychology. - 1380-3395. ; 45:8, s. 763-769
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundWordlist and story recall tests are routinely employed in clinical practice for dementia diagnosis. In this study, our aim was to establish how well-standard clinical metrics compared to process scores derived from wordlist and story recall tests in predicting biomarker determined Alzheimer's disease, as defined by CSF ptau/A & beta;42 ratio.MethodsData from 295 participants (mean age = 65 & PLUSMN; 9.) were drawn from the University of Wisconsin - Madison Alzheimer's Disease Research Center (ADRC) and Wisconsin Registry for Alzheimer's Prevention (WRAP). Rey's Auditory Verbal Learning Test (AVLT; wordlist) and Logical Memory Test (LMT; story) data were used. Bayesian linear regression analyses were carried out with CSF ptau/A & beta;42 ratio as outcome. Sensitivity analyses were carried out with logistic regressions to assess diagnosticity.ResultsLMT generally outperformed AVLT. Notably, the best predictors were primacy ratio, a process score indexing loss of information learned early during test administration, and recency ratio, which tracks loss of recently learned information. Sensitivity analyses confirmed this conclusion.ConclusionsOur study shows that story recall tests may be better than wordlist tests for detection of dementia, especially when employing process scores alongside conventional clinical scores.
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| 4. |
- Bruno, D., et al.
(författare)
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The recency ratio assessed by story recall is associated with cerebrospinal fluid levels of neurodegeneration biomarkers
- 2023
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Ingår i: Cortex. - : Elsevier BV. - 0010-9452. ; 159, s. 167-174
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Tidskriftsartikel (refereegranskat)abstract
- Recency refers to the information learned at the end of a study list or task. Recency forgetting, as tracked by the ratio between recency recall in immediate and delayed con-ditions, i.e., the recency ratio (Rr), has been applied to list-learning tasks, demonstrating its efficacy in predicting cognitive decline, conversion to mild cognitive impairment (MCI), and cerebrospinal fluid (CSF) biomarkers of neurodegeneration. However, little is known as to whether Rr can be effectively applied to story recall tasks. To address this question, data were extracted from the database of the Alzheimer's Disease Research Center at the Uni-versity of Wisconsin -Madison. A total of 212 participants were included in the study. CSF biomarkers were amyloid-beta (Ab) 40 and 42, phosphorylated (p) and total (t) tau, neu-rofilament light (NFL), neurogranin (Ng), and a-synuclein (a-syn). Story Recall was measured with the Logical Memory Test (LMT). We carried out Bayesian regression ana-lyses with Rr, and other LMT scores as predictors; and CSF biomarkers (including the Ab42/ 40 and p-tau/Ab42 ratios) as outcomes. Results showed that models including Rr consis-tently provided best fits with the data, with few exceptions. These findings demonstrate the applicability of Rr to story recall and its sensitivity to CSF biomarkers of neuro-degeneration, and encourage its inclusion when evaluating risk of neurodegeneration with story recall. (c) 2023 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
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| 5. |
- Casaletto, K. B., et al.
(författare)
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Neurogranin, a synaptic protein, is associated with memory independent of Alzheimer biomarkers
- 2017
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Ingår i: Neurology. - 0028-3878. ; 89:17, s. 1782-1788
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To determine the association between synaptic functioning as measured via neurogranin in CSF and cognition relative to established Alzheimer disease (AD) biomarkers in neurologically healthy older adults. Methods: We analyzed CSF concentrations of neurogranin, b-amyloid (Ab42), phosphorylated tau (p-tau), and total tau (t-tau) among 132 neurologically normal older adults (mean 64.5, range 55-85), along with bilateral hippocampal volumes and a measure of episodic memory (Auditory Verbal Learning Test, delayed recall). Univariable analyses examined the relationship between neurogranin and the other AD-related biomarkers. Multivariable regression models examined the relationship between neurogranin and delayed recall, adjusting for age and sex, and interaction terms (neurogranin 3 AD biomarkers). Results: Higher neurogranin concentrations were associated with older age (r 5 0.20, p 5 0.02), lower levels of p-tau and t-tau, and smaller hippocampal volumes (p>0.03), but not with CSF Ab42 (p 5 0.18). In addition, CSF neurogranin demonstrated a significant relationship with memory performance independent of the AD-related biomarkers; individuals with the lowest CSF neurogranin concentrations performed better on delayed recall than those with medium or high CSF neurogranin concentrations (p>0.01). Notably, CSF p-tau, t-tau, and Ab42 and hippocampal volumes were not significantly associated with delayed recall scores (p<0.40), and did not interact with neurogranin to predict memory (p<0.10). © 2017 The Author(s).
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| 6. |
- Darst, B. F., et al.
(författare)
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Pathway-Specific Polygenic Risk Scores as Predictors of Amyloid-beta Deposition and Cognitive Function in a Sample at Increased Risk for Alzheimer's Disease
- 2017
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 55:2, s. 473-484
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Tidskriftsartikel (refereegranskat)abstract
- Polygenic risk scores (PRSs) have been used to combine the effects of variants with small effects identified by genome-wide association studies. We explore the potential for using pathway-specific PRSs as predictors of early changes in Alzheimer's disease (AD)-related biomarkers and cognitive function. Participants were from the Wisconsin Registry for Alzheimer's Prevention, a longitudinal study of adults who were cognitively asymptomatic at enrollment and enriched for a parental history of AD. Using genes associated with AD in the International Genomics of Alzheimer's Project's meta-analysis, we identified clusters of genes that grouped into pathways involved in amyloid-beta (A beta) deposition and neurodegeneration: A beta clearance, cholesterol metabolism, and immune response. Weighted pathway-specific and overall PRSs were developed and compared to APOE alone. Mixed models were used to assess whether each PRS was associated with cognition in 1,200 individuals, cerebral A beta deposition measured using amyloid ligand (Pittsburgh compound B) positron emission imaging in 168 individuals, and cerebrospinal fluid A beta deposition, neurodegeneration, and tau pathology in 111 individuals, with replication performed in an independent sample. We found that PRSs including APOE appeared to be driven by the inclusion of APOE, suggesting that the pathway-specific PRSs used here were not more predictive than an overall PRS or APOE alone. However, pathway-specific PRSs could prove to be useful as more knowledge is gained on the genetic variants involved in specific biological pathways of AD.
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| 7. |
- Deming, Y., et al.
(författare)
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Neuropathology-based APOE genetic risk score better quantifies Alzheimer's risk
- 2023
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Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 19:8, s. 3406-3416
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionApolipoprotein E (APOE) epsilon 4-carrier status or epsilon 4 allele count are included in analyses to account for the APOE genetic effect on Alzheimer's disease (AD); however, this does not account for protective effects of APOE epsilon 2 or heterogeneous effect of epsilon 2, epsilon 3, and epsilon 4 haplotypes. MethodsWe leveraged results from an autopsy-confirmed AD study to generate a weighted risk score for APOE (APOE-npscore). We regressed cerebrospinal fluid (CSF) amyloid and tau biomarkers on APOE variables from the Wisconsin Registry for Alzheimer's Prevention (WRAP), Wisconsin Alzheimer's Disease Research Center (WADRC), and Alzheimer's Disease Neuroimaging Initiative (ADNI). ResultsThe APOE-npscore explained more variance and provided a better model fit for all three CSF measures than APOE epsilon 4-carrier status and epsilon 4 allele count. These findings were replicated in ADNI and observed in subsets of cognitively unimpaired (CU) participants. DiscussionThe APOE-npscore reflects the genetic effect on neuropathology and provides an improved method to account for APOE in AD-related analyses.
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| 8. |
- Dong, R. C., et al.
(författare)
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CSF metabolites associated with biomarkers of Alzheimer's disease pathology
- 2023
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Ingår i: Frontiers in Aging Neuroscience. - 1663-4365. ; 15
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionMetabolomics technology facilitates studying associations between small molecules and disease processes. Correlating metabolites in cerebrospinal fluid (CSF) with Alzheimer's disease (AD) CSF biomarkers may elucidate additional changes that are associated with early AD pathology and enhance our knowledge of the disease.MethodsThe relative abundance of untargeted metabolites was assessed in 161 individuals from the Wisconsin Registry for Alzheimer's Prevention. A metabolome-wide association study (MWAS) was conducted between 269 CSF metabolites and protein biomarkers reflecting brain amyloidosis, tau pathology, neuronal and synaptic degeneration, and astrocyte or microglial activation and neuroinflammation. Linear mixed-effects regression analyses were performed with random intercepts for sample relatedness and repeated measurements and fixed effects for age, sex, and years of education. The metabolome-wide significance was determined by a false discovery rate threshold of 0.05. The significant metabolites were replicated in 154 independent individuals from then Wisconsin Alzheimer's Disease Research Center. Mendelian randomization was performed using genome-wide significant single nucleotide polymorphisms from a CSF metabolites genome-wide association study.ResultsMetabolome-wide association study results showed several significantly associated metabolites for all the biomarkers except A & beta;42/40 and IL-6. Genetic variants associated with metabolites and Mendelian randomization analysis provided evidence for a causal association of metabolites for soluble triggering receptor expressed on myeloid cells 2 (sTREM2), amyloid & beta; (A & beta;40), & alpha;-synuclein, total tau, phosphorylated tau, and neurogranin, for example, palmitoyl sphingomyelin (d18:1/16:0) for sTREM2, and erythritol for A & beta;40 and & alpha;-synuclein.DiscussionThis study provides evidence that CSF metabolites are associated with AD-related pathology, and many of these associations may be causal.
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| 9. |
- Dong, R. C., et al.
(författare)
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Principal components from untargeted cerebrospinal fluid metabolomics associated with Alzheimer's disease biomarkers
- 2022
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580. ; 117, s. 12-23
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Tidskriftsartikel (refereegranskat)abstract
- Studying the correlation between cerebrospinal fluid (CSF) metabolites and the Alzheimer's Disease (AD) biomarkers may offer a window to the alterations of the brain metabolome and unveil potential biological mechanisms underlying AD. In this analysis, 308 CSF metabolites from 338 individuals of Wisconsin Registry for Alzheimer's Prevention and Wisconsin Alzheimer's Disease Research Center were included in a principal component analysis (PCA). The resulted principal components (PCs) were tested for association with CSF total tau (t-tau), phosphorylated tau (p-tau), amyloid beta 42 (A beta 42), and A beta 42/40 ratio using linear regression models. Significant PCs were further tested with other CSF NeuroToolKit (NTK) and imaging biomarkers. Using a Bonferroni corrected p < 0.05, 5 PCs were significantly associated with CSF p-tau and t-tau and 3 PCs were significantly associated with CSF A beta 42. Pathway analysis suggested that these PCS were enriched in 6 pathways, including metabolism of caffeine and nicotinate and nicotinamide. This study provides evidence that CSF metabolites are associated with AD pathology through core AD biomarkers and other NTK markers and suggests potential pathways to follow up in future studies.(c) 2022 Elsevier Inc. All rights reserved.
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| 10. |
- Dong, R., et al.
(författare)
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Csf metabolites associate with csf tau and improve prediction of alzheimer’s disease status
- 2021
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Ingår i: Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring. - : Wiley. - 2352-8729. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Cerebrospinal fluid (CSF) total tau (t-tau) and phosphorylated tau (p-tau) are biomarkers of Alzheimer’s disease (AD), yet much is unknown about AD-associated changes in tau metabolism and tau tangle etiology. Methods: We assessed the variation of t-tau and p-tau explained by 38 previously identified CSF metabolites using linear regression models in middle-age controls from the Wisconsin Alzheimer’s Disease Research Center, and predicted AD/mild cognitive impairment (MCI) versus an independent set of older controls using metabolites selected by the least absolute shrinkage and selection operator (LASSO). Results: The 38 CSF metabolites explained 70.3% and 75.7% of the variance in t-tau and p-tau, respectively. Of these, seven LASSO-selected metabolites improved the prediction ability of AD/MCI versus older controls (area under the curve score increased from 0.92 to 0.97 and 0.78 to 0.93) compared to the base model. Discussion: These tau-correlated CSF metabolites increase AD/MCI prediction accuracy and may provide insight into tau tangle etiology. © 2021 The Authors.
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