| 1. |
- Capogna, Elettra, et al.
(författare)
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Subtypes of brain change in aging and their associations with cognition and Alzheimer's disease biomarkers.
- 2024
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Ingår i: bioRxiv : the preprint server for biology.
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Tidskriftsartikel (refereegranskat)abstract
- Structural brain changes underly cognitive changes in older age and contribute to inter-individual variability in cognition. Here, we assessed how changes in cortical thickness, surface area, and subcortical volume, are related to cognitive change in cognitively unimpaired older adults using structural magnetic resonance imaging (MRI) data-driven clustering. Specifically, we tested (1) which brain structural changes over time predict cognitive change in older age (2) whether these are associated with core cerebrospinal fluid (CSF) Alzheimer's disease (AD) biomarkers phosphorylated tau (p-tau) and amyloid-β (Aβ42), and (3) the degree of overlap between clusters derived from different structural features. In total 1899 cognitively healthy older adults (50 - 93 years) were followed up to 16 years with neuropsychological and structural MRI assessments, a subsample of which (n = 612) had CSF p-tau and Aβ42 measurements. We applied Monte-Carlo Reference-based Consensus clustering to identify subgroups of older adults based on structural brain change patterns over time. Four clusters for each brain feature were identified, representing the degree of longitudinal brain decline. Each brain feature provided a unique contribution to brain aging as clusters were largely independent across modalities. Cognitive change and baseline cognition were best predicted by cortical area change, whereas higher levels of p-tau and Aβ42 were associated with changes in subcortical volume. These results provide insights into the link between changes in brain morphology and cognition, which may translate to a better understanding of different aging trajectories.
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| 2. |
- Halaas, Nathalie Bodd, et al.
(författare)
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Cerebrospinal Fluid Concentration of Neurogranin in Hip Fracture Patients with Delirium.
- 2021
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Ingår i: Journal of Alzheimer's disease : JAD. - : IOS Press. - 1875-8908 .- 1387-2877. ; 81:2, s. 667-677
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Tidskriftsartikel (refereegranskat)abstract
- Delirium is associated with an increased risk of incident dementia and accelerated progression of existing cognitive symptoms. Reciprocally, dementia increases the risk of delirium. Cerebrospinal fluid (CSF) concentration of the dendritic protein neurogranin has been shown to increase in early Alzheimer's disease (AD), likely reflecting synaptic dysfunction and/or degeneration.To elucidate the involvement of synaptic dysfunction in delirium pathophysiology, we tested the association between CSF neurogranin concentration and delirium in hip fracture patients with different AD-biomarker profiles, while comparing them to cognitively unimpaired older adults (CUA) and AD patients.The cohort included hip fracture patients with (n=70) and without delirium (n=58), CUA undergoing elective surgery (n=127), and AD patients (n=46). CSF was collected preoperatively and diagnostically in surgery and AD patients respectively. CSF neurogranin concentrations were analyzed in all samples with an in-house ELISA. Delirium was assessed pre-and postoperatively in hip fracture patients by trained investigators using the Confusion Assessment Method. Hip fracture patients were further stratified based on pre-fracture dementia status, delirium subtype, and AD fluid biomarkers.No association was found between delirium and CSF neurogranin concentration (main analysis: delirium versus no delirium, p=0.68). Hip fracture patients had lower CSF neurogranin concentration than AD patients (p=0.001) and CUA (p=0.035) in age-adjusted sensitivity analyses.The findings suggest that delirium is not associated with increased CSF neurogranin concentration in hip fracture patients, possibly due to advanced neurodegenerative disease and age and/or because synaptic degeneration is not an important pathophysiological process in delirium.
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| 3. |
- Halaas, Nathalie Bodd, et al.
(författare)
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CSF sTREM2 and Tau Work Together in Predicting Increased Temporal Lobe Atrophy in Older Adults.
- 2020
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Ingår i: Cerebral cortex (New York, N.Y. : 1991). - : Oxford University Press (OUP). - 1460-2199 .- 1047-3211. ; 30:4, s. 2295-2306
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Tidskriftsartikel (refereegranskat)abstract
- Neuroinflammation may be a key factor in brain atrophy in aging and age-related neurodegenerative disease. The objective of this study was to test the association between microglial expression of soluble Triggering Receptor Expressed on Myeloid Cells 2 (sTREM2), as a measure of neuroinflammation, and brain atrophy in cognitively unimpaired older adults. Brain magnetic resonance imagings (MRIs) and cerebrospinal fluid (CSF) sTREM2, total tau (t-tau), phosphorylated181 tau (p-tau), and Aβ42 were analyzed in 115 cognitively unimpaired older adults, classified according to the A/T/(N)-framework. MRIs were repeated after 2 (n=95) and 4 (n=62) years. High baseline sTREM2 was associated with accelerated cortical thinning in the temporal cortex of the left hemisphere, as well as bilateral hippocampal atrophy, independently of age, Aβ42, and tau. sTREM2-related atrophy only marginally increased with biomarker positivity across the AD continuum (A-T- #x2292; A+T- #x2292; A+T+) but was significantly stronger in participants with a high level of p-tau (T+). sTREM2-related cortical thinning correlated significantly with areas of high microglial-specific gene expression in the Allen Human Brain Atlas. In conclusion, increased CSF sTREM2 was associated with accelerated cortical and hippocampal atrophy in cognitively unimpaired older participants, particularly in individuals with tau pathology. This suggests a link between neuroinflammation, neurodegeneration, and amyloid-independent tauopathy.
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| 4. |
- Halaas, Nathalie Bodd, et al.
(författare)
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Neurofilament Light in Serum and Cerebrospinal Fluid of Hip Fracture Patients with Delirium.
- 2018
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Ingår i: Dementia and geriatric cognitive disorders. - : S. Karger AG. - 1421-9824 .- 1420-8008. ; 46:5-6, s. 346-357
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Tidskriftsartikel (refereegranskat)abstract
- Delirium is associated with new-onset dementia, suggesting that delirium pathophysiology involves neuronal injury. Neurofilament light (NFL) is a sensitive biomarker for neuroaxonal injury.NFL was measured in cerebrospinal fluid (CSF) (n = 130), preoperative serum (n = 192), and postoperative serum (n = 280) in hip fracture patients, and in CSF (n = 123) and preoperative serum (n = 134) in cognitively normal older adults undergoing elective surgery. Delirium was diagnosed with the Confusion Assessment Method.Median serum NFL (pg/mL) was elevated in delirium in hip fracture patients (94 vs. 54 pre- and 135 vs. 92 postoperatively, both p < 0.001). Median CSF NFL tended to be higher in hip fracture patients with delirium (1,804 vs. 1,636, p = 0.074). Serum and CSF NFL were positively correlated (ρ = 0.56, p < 0.001).Our findings support an association between neuroaxonal injury and delirium. The correlation between serum and CSF NFL supports the use of NFL as a blood biomarker in future delirium studies.
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| 5. |
- Watne, Leiv Otto, et al.
(författare)
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Cerebrospinal fluid quinolinic acid is strongly associated with delirium and mortality in hip fracture patients.
- 2023
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Ingår i: The Journal of clinical investigation. - 1558-8238. ; 133:2
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Tidskriftsartikel (refereegranskat)abstract
- The kynurenine pathway (KP) has been identified as a potential mediator linking acute illness to cognitive dysfunction by generating neuroactive metabolites in response to inflammation. Delirium (acute confusion) is a common complication of acute illness and is associated with increased risk of dementia and mortality. However, the molecular mechanism underlying delirium, particularly in relation to the KP, remain elusive.We undertook a multi-center observational study with 586 hospitalized patients (248 with delirium) and investigated associations between delirium and KP metabolites measured in cerebrospinal fluid (CSF) and serum by targeted metabolomics. We also explored associations between KP metabolites and markers of neuronal damage and one-year mortality.In delirium, we found concentrations of the neurotoxic metabolite quinolinic acid in CSF (CSF-QA, OR 2.26 [1.78, 2.87], p<0.001) to be increased, as well as increases in several other KP metabolites in serum and CSF. In addition, CSF-QA was associated with the neuronal damage marker neurofilament light chain (NfL, β 0.43, p<0.001) and was a strong predictor of one-year mortality (HR 4.35 [2.93, 6.45] for CSF-QA ≥ 100 nmol/L, p<0.001). The associations between CSF-QA and delirium, neuronal damage, and mortality remained highly significant following adjustment for confounders and multiple comparisons.Our data identified how systemic inflammation, neurotoxicity, and delirium are strongly linked via the KP, and should inform future delirium prevention and treatment clinical trials that target enzymes of the KP.Norwegian Health Association and the South-Eastern Norway Regional Health Authorities.
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