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  • 1
    In: Nature Communications, Springer Science and Business Media LLC, Vol. 12, No. 1 ( 2021-08-05)
    Materialart: Online-Ressource
    ISSN: 2041-1723
    Sprache: Englisch
    Verlag: Springer Science and Business Media LLC
    Publikationsdatum: 2021
    ZDB Id: 2553671-0
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    In: Brain, Oxford University Press (OUP), ( 2024-02-07)
    Kurzfassung: Synaptic dysfunction and degeneration is likely the key pathophysiology for the progression of cognitive decline in various dementia disorders. Synaptic status can be monitored by measurement of synaptic proteins in cerebrospinal fluid (CSF). In the current study, the aim was to investigate and compare both known and new synaptic proteins as potential biomarkers of synaptic dysfunction, especially in the context of Alzheimer’s disease (AD). Seventeen synaptic proteins were quantified in CSF using two different targeted mass spectrometry assays in the prospective Swedish BioFINDER-2 study. The study included 958 individuals, characterized as having mild cognitive impairment (MCI, n = 205), AD dementia (n = 149), and a spectrum of other neurodegenerative diseases (n = 171), as well as cognitively unimpaired (CU, n = 443). Synaptic protein levels were compared between diagnostic groups and their associations with cognitive decline and key neuroimaging measures (Aβ-PET, tau-PET, and cortical thickness) were assessed. Among the 17 synaptic proteins examined, 14 were specifically elevated in the AD continuum. SNAP-25, 14-3-3 zeta/delta, beta-synuclein, and neurogranin exhibited the highest discriminatory accuracy to differentiate AD dementia from controls (AUCs = 0.81-0.93). SNAP-25 and 14-3-3 zeta/delta also had the strongest associations with tau-PET, Aβ-PET, and cortical thickness at baseline, and were associated with longitudinal changes in these imaging biomarkers (β(SE)=-0.056(0.0006) to 0.058(0.005), p & lt; 0.0001). SNAP-25 was the strongest predictor of progression to AD dementia in non-demented individuals (Hazard ratio = 2.11). In contrast, neuronal pentraxins were decreased in all neurodegenerative diseases (except for Parkinson’s disease), and NPTX2 showed the strongest associations with subsequent cognitive decline (longitudinal MMSE; β(SE) = 0.57(0.1), p ≤ 0.0001 and mPACC; β(SE) = 0.095(0.024), p ≤ 0.001) across the AD continuum. Interestingly, utilizing a ratio of the proteins that displayed higher levels in AD, such as SNAP-25 or 14-3-3 zeta/delta, over NPTX2 improved the biomarkers’ association with cognitive decline and brain atrophy. We found that especially 14-3-3 zeta/delta and SNAP-25 are promising synaptic biomarkers of pathophysiological changes in AD. Neuronal pentraxins were identified as general indicators of neurodegeneration and associated with cognitive decline across various neurodegenerative dementias. The ratios of SNAP-25/NPTX2 and 14-3-3 zeta/delta/NPTX2 were found to best predict cognitive decline and brain atrophy.
    Materialart: Online-Ressource
    ISSN: 0006-8950 , 1460-2156
    RVK:
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2024
    ZDB Id: 1474117-9
    SSG: 12
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    In: Nature Communications, Springer Science and Business Media LLC, Vol. 11, No. 1 ( 2020-05-26)
    Kurzfassung: Tau is a hallmark pathology of Alzheimer’s disease, and animal models have suggested that tau spreads from cell to cell through neuronal connections, facilitated by β -amyloid (A β ). We test this hypothesis in humans using an epidemic spreading model (ESM) to simulate tau spread, and compare these simulations to observed patterns measured using tau-PET in 312 individuals along Alzheimer’s disease continuum. Up to 70% of the variance in the overall spatial pattern of tau can be explained by our model. Surprisingly, the ESM predicts the spatial patterns of tau irrespective of whether brain A β is present, but regions with greater A β burden show greater tau than predicted by connectivity patterns, suggesting a role of A β in accelerating tau spread. Altogether, our results provide evidence in humans that tau spreads through neuronal communication pathways even in normal aging, and that this process is accelerated by the presence of brain A β .
    Materialart: Online-Ressource
    ISSN: 2041-1723
    Sprache: Englisch
    Verlag: Springer Science and Business Media LLC
    Publikationsdatum: 2020
    ZDB Id: 2553671-0
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    In: Brain Communications, Oxford University Press (OUP), Vol. 4, No. 3 ( 2022-05-02)
    Kurzfassung: A growing body of evidence suggests that astrocytes play a major role in the pathophysiology of Alzheimer’s disease. Given that APOE is primarily expressed in astrocytes, these cells might be an important link between the APOE ε4 allele and the development of Alzheimer’s disease pathology. Here, we investigate this hypothesis in vivo by measuring myo-inositol, a metabolite involved in astrocytic functions, with magnetic resonance spectroscopy. Currently, there is conflicting evidence regarding the relationship between APOE ε4 and myo-inositol concentration. Furthermore, data supporting a relationship between APOE ε4, myo-inositol and Alzheimer’s disease pathology (amyloid-beta and tau proteins) in the preclinical stage of Alzheimer’s disease are limited. A previous study revealed differences in myo-inositol levels between APOE ε4 carriers and non-carriers already in preclinical Alzheimer’s disease participants. However, other reports showed no impact of APOE genotype on the association between myo-inositol and the rate of amyloid-beta accumulation. In the present study, we determined the effect of APOE genotype on the association between myo-inositol and both amyloid-β and tau deposition quantified by PET in 428 cognitively unimpaired elderly and patients with mild cognitive impairment from the Swedish BioFINDER-2 cohort. APOE genotype impacted the associations between myo-inositol and amyloid-β pathology as revealed by an interaction effect between APOE genotype and levels of myo-inositol (P  & lt; 0.001) such that higher myo-inositol concentration was related to more amyloid-beta pathology in APOE ε4 carriers only. A similar interaction effect was also found when investigating the effect of APOE on the association between myo-inositol and tau pathology (P  & lt; 0.01). Focusing on the APOE ε4 subsample, myo-inositol partially (17%) mediated the association between amyloid-beta and tau pathology (P  & lt; 0.05). Furthermore, in a subgroup of participants with available plasma levels of glial fibrillary acidic protein, a marker of astroglial activation and astrocytosis, we found that glial fibrillary acidic protein correlated with myo-inositol only in APOE e4 carriers (APOE ε4 carriers: P  & lt; 0.01; APOE ε4 non-carriers: P  & gt; 0.8), suggesting that myo-inositol might reflect an aspect of the astrocytic involvement in Alzheimer’s pathology which is specific to the impact of APOE ε4. Therefore, we suggest that myo-inositol is a candidate in vivo marker to study the impact of APOE ε4 on the interplay between astrocytes and the pathophysiology of Alzheimer’s disease.
    Materialart: Online-Ressource
    ISSN: 2632-1297
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2022
    ZDB Id: 3020013-1
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  • 5
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S1 ( 2022-12)
    Kurzfassung: For optimal design of anti‐amyloid‐β (Aβ) and anti‐tau clinical trials, it is important to understand how Aβ and soluble phosphorylated tau (p‐tau) relate to the accumulation of tau aggregates assessed with positron emission tomography (PET) and subsequent cognitive decline across the Alzheimer's disease (AD) continuum. Method We included 327 participants from the Swedish BioFINDER‐2 cohort with cerebrospinal fluid (CSF) p‐tau217, Aβ‐PET, longitudinal tau‐PET, and longitudinal cognition. The main groups of interest were Aβ‐positive non‐demented participants and AD dementia patients (Table 1 and Figure 1), and analyses were conducted separately in each group. First, we investigated how soluble p‐tau217 and regional Aβ‐PET were associated with tau‐PET rate of change across the 200 brain parcels from the Schaefer atlas. We also tested the mediating effect of p‐tau217 between Aβ‐PET and tau‐PET change. Second, we investigated how soluble p‐tau217 and tau‐PET change related to change in cognition, and mediation between these variables. Result In early AD stages (non‐demented participants), increased concentration of soluble p‐tau217 was the main driver of accumulation of insoluble tau aggregates across the brain (measured as tau‐PET rate of change), beyond the effect of regional Aβ‐PET and baseline tau‐PET (Figure 2A‐C). Further, averaged across all regions, soluble p‐tau217 mediated 54% of the association between Aβ and tau aggregation (Figure 2D). Higher soluble p‐tau217 concentrations were also associated with cognitive decline, which was mediated by faster increase of tau aggregates (Figure 3). Repeating the same analyses in the AD dementia group, results were different. In late stage of AD, when Aβ fibrils and soluble p‐tau levels have plateaued, soluble p‐tau217 was not associated with accumulation of tau aggregates beyond baseline tau‐PET (Figure 4A), and cognitive decline was driven by the accumulation rate of insoluble tau aggregates and not soluble p‐tau217 (Figure 4B‐C). Conclusion Soluble p‐tau is a main driver of tau aggregation and future cognitive decline in earlier stages of AD, whereas tau aggregation accumulation is more likely an important driver of disease in later stages. Overall, our data suggest that therapeutic approaches reducing soluble p‐tau levels might be most favorable in early AD.
    Materialart: Online-Ressource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2022
    ZDB Id: 2201940-6
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    In: NeuroImage, Elsevier BV, Vol. 296 ( 2024-08), p. 120672-
    Materialart: Online-Ressource
    ISSN: 1053-8119
    Sprache: Englisch
    Verlag: Elsevier BV
    Publikationsdatum: 2024
    ZDB Id: 1471418-8
    SSG: 5,2
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    In: Alzheimer's & Dementia, Wiley, Vol. 18, No. S6 ( 2022-12)
    Kurzfassung: For optimal design of anti‐amyloid‐β (Aβ) and anti‐tau clinical trials, it is important to understand how Aβ and soluble phosphorylated tau (p‐tau) relate to the accumulation of tau aggregates assessed with positron emission tomography (PET) and subsequent cognitive decline across the Alzheimer's disease (AD) continuum. Method We included 327 participants from the Swedish BioFINDER‐2 cohort with cerebrospinal fluid (CSF) p‐tau217, Aβ‐PET, longitudinal tau‐PET, and longitudinal cognition. The main groups of interest were Aβ‐positive non‐demented participants and AD dementia patients (Table 1 and Figure 1), and analyses were conducted separately in each group. First, we investigated how soluble p‐tau217 and regional Aβ‐PET were associated with tau‐PET rate of change across the 200 brain parcels from the Schaefer atlas. We also tested the mediating effect of p‐tau217 between Aβ‐PET and tau‐PET change. Second, we investigated how soluble p‐tau217 and tau‐PET change related to change in cognition, and mediation between these variables. Result In early AD stages (non‐demented participants), increased concentration of soluble p‐tau217 was the main driver of accumulation of insoluble tau aggregates across the brain (measured as tau‐PET rate of change), beyond the effect of regional Aβ‐PET and baseline tau‐PET (Figure 2A‐C). Further, averaged across all regions, soluble p‐tau217 mediated 54% of the association between Aβ and tau aggregation (Figure 2D). Higher soluble p‐tau217 concentrations were also associated with cognitive decline, which was mediated by faster increase of tau aggregates (Figure 3). Repeating the same analyses in the AD dementia group, results were different. In late stage of AD, when Aβ fibrils and soluble p‐tau levels have plateaued, soluble p‐tau217 was not associated with accumulation of tau aggregates beyond baseline tau‐PET (Figure 4A), and cognitive decline was driven by the accumulation rate of insoluble tau aggregates and not soluble p‐tau217 (Figure 4B‐C). Conclusion Soluble p‐tau is a main driver of tau aggregation and future cognitive decline in earlier stages of AD, whereas tau aggregation accumulation is more likely an important driver of disease in later stages. Overall, our data suggest that therapeutic approaches reducing soluble p‐tau levels might be most favorable in early AD.
    Materialart: Online-Ressource
    ISSN: 1552-5260 , 1552-5279
    URL: Issue
    Sprache: Englisch
    Verlag: Wiley
    Publikationsdatum: 2022
    ZDB Id: 2201940-6
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    Online-Ressource
    Online-Ressource
    Oxford University Press (OUP) ; 2023
    In:  Brain Vol. 146, No. 4 ( 2023-04-19), p. 1602-1614
    In: Brain, Oxford University Press (OUP), Vol. 146, No. 4 ( 2023-04-19), p. 1602-1614
    Kurzfassung: Markers of downstream events are a key component of clinical trials of disease-modifying therapies for Alzheimer’s disease. Morphological metrics like cortical thickness are established measures of atrophy but are not sensitive enough to detect amyloid-beta (Aβ)- related changes that occur before overt atrophy become visible. We aimed to investigate to what extent diffusion MRI can provide sensitive markers of cortical microstructural changes and to test their associations with multiple aspects of the Alzheimer’s disease pathological cascade, including both Aβ and tau accumulation, astrocytic activation and cognitive deficits. We applied the mean apparent diffusion propagator model to diffusion MRI data from 492 cognitively unimpaired elderly and patients with mild cognitive impairment from the Swedish BioFINDER-2 cohort. Participants were stratified in Aβ-negative/tau-negative, Aβ-positive/tau-negative and Aβ-positive/tau-positive based on Aβ- and tau-PET uptake. Cortical regional values of diffusion MRI metrics and cortical thickness were compared across groups. Associations between regional values of diffusion MRI metrics and both Aβ- and tau-PET uptake were also investigated along with the association with plasma level of glial fibrillary acidic protein (GFAP), a marker of astrocyte activation (available in 292 participants). Mean squared displacement revealed widespread microstructural differences already between Aβ-negative/tau-negative and Aβ-positive/tau-negative participants with a spatial distribution that closely resembled the pattern of Aβ accumulation. In contrast, differences in cortical thickness were clearly more limited. Mean squared displacement was also correlated with both Aβ- and tau-PET uptake even independently from one another and from cortical thickness. Further, the same metric exhibited significantly stronger correlations with PET uptake than cortical thickness (P & lt; 0.05). Mean squared displacement was also positively correlated with GFAP with a pattern that resembles Aβ accumulation, and GFAP partially mediated the association between Aβ accumulation and mean squared displacement. Further, impairments in executive functions were significantly more associated with mean squared displacement values extracted from a meta-region of interest encompassing regions accumulating Aβ early in the disease process, than with cortical thickness (P & lt; 0.05). Similarly, impairments in memory functions were significantly more associated with mean squared displacement values extracted from a temporal meta-region of interest than with cortical thickness (P & lt; 0.05). Metrics of cortical microstructural alteration derived from diffusion MRI are highly sensitive to multiple aspects of the Alzheimer’s disease pathological cascade. Of particular interest is the link with both Aβ-PET and GFAP, suggesting diffusion MRI might reflects microstructural changes related to the astrocytic response to Aβ aggregation. Therefore, metrics of cortical diffusion might be important outcome measures in anti-Aβ treatments clinical trials for detecting drug-induced changes in cortical microstructure.
    Materialart: Online-Ressource
    ISSN: 0006-8950 , 1460-2156
    RVK:
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2023
    ZDB Id: 1474117-9
    SSG: 12
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    In: Brain, Oxford University Press (OUP), Vol. 146, No. 8 ( 2023-08-01), p. 3192-3205
    Kurzfassung: Amyloid-β (Aβ) is hypothesized to facilitate the spread of tau pathology beyond the medial temporal lobe. However, there is evidence that, independently of Aβ, age-related tau pathology might be present outside of the medial temporal lobe. We therefore aimed to study age-related Aβ-independent tau deposition outside the medial temporal lobe in two large cohorts and to investigate potential downstream effects of this on cognition and structural measures. We included 545 cognitively unimpaired adults (40–92 years) from the BioFINDER-2 study (in vivo) and 639 (64–108 years) from the Rush Alzheimer’s Disease Center cohorts (ex vivo). 18F-RO948- and 18F-flutemetamol-PET standardized uptake value ratios were calculated for regional tau and global/regional Aβ in vivo. Immunohistochemistry was used to estimate Aβ load and tangle density ex vivo. In vivo medial temporal lobe volumes (subiculum, cornu ammonis 1) and cortical thickness (entorhinal cortex, Brodmann area 35) were obtained using Automated Segmentation for Hippocampal Subfields packages. Thickness of early and late neocortical Alzheimer’s disease regions was determined using FreeSurfer. Global cognition and episodic memory were estimated to quantify cognitive functioning. In vivo age-related tau deposition was observed in the medial temporal lobe and in frontal and parietal cortical regions, which was statistically significant when adjusting for Aβ. This was also observed in individuals with low Aβ load. Tau deposition was negatively associated with cortical volumes and thickness in temporal and parietal regions independently of Aβ. The associations between age and cortical volume or thickness were partially mediated via tau in regions with early Alzheimer’s disease pathology, i.e. early tau and/or Aβ pathology (subiculum/Brodmann area 35/precuneus/posterior cingulate). Finally, the associations between age and cognition were partially mediated via tau in Brodmann area 35, even when including Aβ-PET as covariate. Results were validated in the ex vivo cohort showing age-related and Aβ-independent increases in tau aggregates in and outside the medial temporal lobe. Ex vivo age-cognition associations were mediated by medial and inferior temporal tau tangle density, while correcting for Aβ density. Taken together, our study provides support for primary age-related tauopathy even outside the medial temporal lobe in vivo and ex vivo, with downstream effects on structure and cognition. These results have implications for our understanding of the spreading of tau outside the medial temporal lobe, also in the context of Alzheimer’s disease. Moreover, this study suggests the potential utility of tau-targeting treatments in primary age-related tauopathy, likely already in preclinical stages in individuals with low Aβ pathology.
    Materialart: Online-Ressource
    ISSN: 0006-8950 , 1460-2156
    RVK:
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2023
    ZDB Id: 1474117-9
    SSG: 12
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    In: Brain, Oxford University Press (OUP), ( 2023-09-18)
    Kurzfassung: Cerebrovascular pathology often co-exists with Alzheimer’s disease pathology and can contribute to Alzheimer’s disease-related clinical progression. However, the degree to which vascular burden contributes to Alzheimer’s disease pathological progression is still unclear. This study aimed to investigate interactions between vascular burden and amyloid-β pathology on both baseline tau tangle load and longitudinal tau accumulation. We included 1,229 participants from the Swedish BioFINDER-2 Study, including cognitively unimpaired and impaired participants with and without biomarker-confirmed amyloid-β pathology. All underwent baseline tau-PET ([18F]RO948) and a subset (n = 677) underwent longitudinal tau-PET after 2.5 ± 1.0 years. Tau-PET uptake was computed for a temporal meta-region-of-interest. We focused on four main vascular imaging features and risk factors: microbleeds, white matter lesion volume, stroke-related events (infarcts, lacunes and haemorrhages), and the Framingham Heart Study Cardiovascular Disease risk score. To validate our in vivo results, we examined 1,610 autopsy cases from an Arizona-based neuropathology cohort on three main vascular pathological features: cerebral amyloid angiopathy, white matter rarefaction and infarcts. For the in vivo cohort, primary analyses included age-, sex- and APOE ε4-corrected linear mixed models between tau-PET (outcome) and interactions between time, amyloid-β and each vascular feature (predictors). For the neuropathology cohort, age-, sex- and APOE ε4-corrected linear models between tau tangle density (outcome) and an interaction between plaque density and each vascular feature (predictors) were performed. In cognitively unimpaired individuals, we observed a significant interaction between microbleeds and amyloid-β pathology on greater baseline tau load (β=0.68, p  & lt; 0.001) and longitudinal tau accumulation (β=0.11, p  & lt; 0.001). For white matter lesion volume, we did not observe a significant independent interaction effect with amyloid-β on tau after accounting for microbleeds. In cognitively unimpaired individuals we further found that stroke-related events showed a significant negative interaction with amyloid-β on longitudinal tau (β=-0.08, p  & lt; 0.001). In cognitively impaired individuals, there were no significant interaction effects between cerebrovascular and amyloid-β pathology at all. In the neuropathology dataset, the in-vivo observed interaction effects between cerebral amyloid angiopathy and plaque density (β=0.38, p  & lt; 0.001) and between infarcts and plaque density (β=-0.11, p = 0.005) on tau tangle density were replicated. To conclude, we demonstrated that cerebrovascular pathology - in the presence of amyloid-β pathology - modifies tau accumulation in early stages of Alzheimer’s disease. More specifically, the co-occurrence of microbleeds and amyloid-β pathology was associated with greater accumulation of tau aggregates during early disease stages. This opens the possibility that interventions targeting microbleeds may attenuate the rate of tau accumulation in Alzheimer’s disease.
    Materialart: Online-Ressource
    ISSN: 0006-8950 , 1460-2156
    RVK:
    Sprache: Englisch
    Verlag: Oxford University Press (OUP)
    Publikationsdatum: 2023
    ZDB Id: 1474117-9
    SSG: 12
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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