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Sewell KR, Rainey-Smith SR, Pedrini S, Peiffer JJ, Sohrabi HR, Taddei K, Markovic SJ, Martins RN, Brown BM. The impact of exercise on blood-based biomarkers of Alzheimer's disease in cognitively unimpaired older adults. GeroScience 2024; 46:5911-5923. [PMID: 38488949 PMCID: PMC11493998 DOI: 10.1007/s11357-024-01130-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2024] [Accepted: 03/08/2024] [Indexed: 03/17/2024] Open
Abstract
Physical activity is a promising preventative strategy for Alzheimer's disease: it is associated with lower dementia risk, better cognition, greater brain volume and lower brain beta-amyloid. Blood-based biomarkers have emerged as a low-cost, non-invasive strategy for detecting preclinical Alzheimer's disease, however, there is limited literature examining the effect of exercise (a structured form of physical activity) on blood-based biomarkers. The current study investigated the influence of a 6-month exercise intervention on levels of plasma beta-amyloid (Aβ42, Aβ40, Aβ42/40), phosphorylated tau (p-tau181), glial fibrillary acidic protein (GFAP) and neurofilament light (NfL) chain in cognitively unimpaired older adults, and as a secondary aim, whether blood-based biomarkers related to cognition. Ninety-nine community-dwelling older adults (69.1 ± 5.2) were allocated to an inactive control, or to moderate or high intensity exercise groups where they cycled twice weekly for six months. At baseline and six months (post-intervention), fasted blood was collected and analysed using single molecule array (SIMOA) assays, and cognition was assessed. Results demonstrated no change in levels of any plasma biomarker from pre- to post-intervention. At baseline, higher NfL was associated with poorer cognition (β = -0.33, SE = 0.13, adjusted p = .042). Exploratory analyses indicated higher cardiorespiratory fitness was associated with higher NfL and GFAP levels in apolipoprotein E (APOE) ε4 non-carriers compared to ε4 carriers (NfL, β = -0.43, SE = 0.19, p = .029; GFAP, β = -0.41, SE = 0.20, p = .044), though this association was mediated by body mass index (BMI). These results highlight the importance of considering BMI in analysis of blood-based biomarkers, especially when investigating differences between APOE ε4 carriers and non-carriers. Our results also indicate that longer follow-up periods may be required to observe exercise-induced change in blood-based biomarkers.
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Soh N, Weinborn M, Doecke JD, Canovas R, Doré V, Xia Y, Fripp J, Taddei K, Bucks RS, Sohrabi HR, Martins RN, Ree M, Rainey-Smith SR. Sleep discrepancy and brain glucose metabolism in community-dwelling older adults. AGING BRAIN 2024; 6:100130. [PMID: 39735205 PMCID: PMC11674432 DOI: 10.1016/j.nbas.2024.100130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Revised: 11/01/2024] [Accepted: 11/03/2024] [Indexed: 12/31/2024] Open
Abstract
Sleep discrepancy (negative discrepancy reflects worse self-reported sleep than objective measures, such as actigraphy, and positive discrepancy the opposite) has been linked to adverse health outcomes. This study is first to investigate the relationship between sleep discrepancy and brain glucose metabolism (assessed globally and regionally via positron emission tomography), and to evaluate the contribution of insomnia severity and depressive symptoms to any associations. Using data from cognitively unimpaired community-dwelling older adults (N = 68), cluster analysis was used to characterise sleep discrepancy (for total sleep time (TST), wake after sleep onset (WASO), and sleep efficiency (SE)), and logistic regression was used to explore sleep discrepancy's associations with brain glucose metabolism, while controlling for insomnia severity and depressive symptoms. Lower glucose metabolism across multiple brain regions was associated with negative discrepancy for WASO and SE, and positive discrepancy for WASO only (large effect sizes; β ≥ 0.5). Higher glucose metabolism in the superior parietal and posterior cingulate regions was associated with negative discrepancy for TST (large effect sizes; β ≥ 0.5). These associations remained when controlling for insomnia severity and depressive symptoms, suggesting a unique role of sleep discrepancy as a potential early behavioural marker of brain health.
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Feizpour A, Doecke JD, Doré V, Krishnadas N, Huang K, Bourgeat P, Laws SM, Fowler C, Robertson J, Mackintosh L, Ayton S, Martins R, Rainey-Smith SR, Taddei K, Ward L, Stage E, Bannon AW, Masters CL, Fripp J, Villemagne VL, Rowe CC. Detection and staging of Alzheimer's disease by plasma pTau217 on a high throughput immunoassay platform. EBioMedicine 2024; 109:105405. [PMID: 39437657 PMCID: PMC11536028 DOI: 10.1016/j.ebiom.2024.105405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2024] [Revised: 09/29/2024] [Accepted: 10/02/2024] [Indexed: 10/25/2024] Open
Abstract
BACKGROUND Plasma phospho-tau 217 (pTau217) assays can accurately detect Alzheimer's disease (AD) pathology, but clinical application is limited by the need for specialised equipment. This study tests the performance of a plasma pTau217 assay performed on the Lumipulse-G® platform, that is in widespread clinical use, for selecting patients for therapy based on β-amyloid (Aβ) status and tau staging. METHODS Participants included 388 individuals with 18F-NAV4694 Aβ-PET and 18F-MK6240 tau-PET. Association of pTau217 with PET was examined using Spearman's correlation. Discriminative performance for Aβ and tau PET status as well as tau staging was assessed using Receiver Operating Characteristic analysis. FINDINGS Plasma pTau217 had a high correlation with both Aβ Centiloid (r = 0.76) and tau SUVRmeta-temporal (r = 0.78). Area under curve (AUC) was 0.93 for Aβ- vs Aβ+ and 0.94 for tau- vs tau+. Applying one threshold (Youden's index), pTau217 was 87% accurate in classification of participants to Aβ- vs Aβ+. Applying two thresholds to classify participants into Low, Indeterminate, and High zones, 17.8% had Indeterminate results and among Low/High zone participants, 92% were correctly classified as Aβ- or Aβ+. The assay accurately discriminated moderate/high neocortical tau from no tau or tau limited to mesial-temporal lobe (AUC 0.97) and high neocortical tau from all others (AUC 0.94). INTERPRETATION Plasma pTau217, measured by the widely-available, fully-automated Lumipulse®, was a strong predictor of both Aβ and tau PET status and demonstrated strong predictive power in identifying individuals likely to benefit the most from anti-Aβ treatments. FUNDING NHMRC grants 1132604, 1140853, 1152623 and AbbVie.
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Gardener SL, Fuller SJ, Naismith SL, Baker L, Kivipelto M, Villemagne VL, Grieve SM, Yates P, Rainey‐Smith SR, Chen J, Thompson B, Armstrong NJ, Fernando MG, Blagojevic Castro C, Meghwar S, Raman R, Gleason A, Ireland C, Clarnette R, Anstey KJ, Taddei K, Garg M, Sohrabi HR, Martins RN. The AUstralian multidomain Approach to Reduce dementia Risk by prOtecting brain health With lifestyle intervention study (AU-ARROW): A study protocol for a single-blind, multi-site, randomized controlled trial. ALZHEIMER'S & DEMENTIA (NEW YORK, N. Y.) 2024; 10:e12466. [PMID: 38596483 PMCID: PMC11002765 DOI: 10.1002/trc2.12466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2023] [Revised: 03/07/2024] [Accepted: 03/09/2024] [Indexed: 04/11/2024]
Abstract
INTRODUCTION The Finnish Geriatric Intervention Study (FINGER) led to the global dementia risk reduction initiative: World-Wide FINGERS (WW-FINGERS). As part of WW-FINGERS, the Australian AU-ARROW study mirrors aspects of FINGER, as well as US-POINTER. METHOD AU-ARROW is a randomized, single-blind, multisite, 2-year clinical trial (n = 600; aged 55-79). The multimodal lifestyle intervention group will engage in aerobic exercise, resistance training and stretching, dietary advice to encourage MIND diet adherence, BrainHQ cognitive training, and medical monitoring and health education. The Health Education and Coaching group will receive occasional health education sessions. The primary outcome measure is the change in a global composite cognitive score. Extra value will emanate from blood biomarker analysis, positron emission tomography (PET) imaging, brain magnetic resonance imaging (MRI), and retinal biomarker tests. DISCUSSION The finalized AU-ARROW protocol is expected to allow development of an evidence-based innovative treatment plan to reduce cognitive decline and dementia risk, and effective transfer of research outcomes into Australian health policy. Highlights Study protocol for a single-blind, randomized controlled trial, the AU-ARROW Study.The AU-ARROW Study is a member of the World-Wide FINGERS (WW-FINGERS) initiative.AU-ARROW's primary outcome measure is change in a global composite cognitive score.Extra significance from amyloid PET imaging, brain MRI, and retinal biomarker tests.Leading to development of an innovative treatment plan to reduce cognitive decline.
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Pivac LN, Brown BM, Sewell KR, Doecke JD, Villemagne VL, Doré V, Weinborn M, Sohrabi HR, Gardener SL, Bucks RS, Laws SM, Taddei K, Maruff P, Masters CL, Rowe C, Martins RN, Rainey‐Smith SR. Suboptimal self-reported sleep efficiency and duration are associated with faster accumulation of brain amyloid beta in cognitively unimpaired older adults. ALZHEIMER'S & DEMENTIA (AMSTERDAM, NETHERLANDS) 2024; 16:e12579. [PMID: 38651160 PMCID: PMC11033837 DOI: 10.1002/dad2.12579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/28/2024] [Accepted: 03/10/2024] [Indexed: 04/25/2024]
Abstract
INTRODUCTION This study investigated whether self-reported sleep quality is associated with brain amyloid beta (Aβ) accumulation. METHODS Linear mixed effect model analyses were conducted for 189 cognitively unimpaired (CU) older adults (mean ± standard deviation 74.0 ± 6.2; 53.2% female), with baseline self-reported sleep data, and positron emission tomography-determined brain Aβ measured over a minimum of three time points (range 33.3-72.7 months). Analyses included random slopes and intercepts, interaction for apolipoprotein E (APOE) ε4 allele status, and time, adjusting for sex and baseline age. RESULTS Sleep duration <6 hours, in APOE ε4 carriers, and sleep efficiency <65%, in the whole sample and APOE ε4 non-carriers, is associated with faster accumulation of brain Aβ. DISCUSSION These findings suggest a role for self-reported suboptimal sleep efficiency and duration in the accumulation of Alzheimer's disease (AD) neuropathology in CU individuals. Additionally, poor sleep efficiency represents a potential route via which individuals at lower genetic risk may progress to preclinical AD. Highlights In cognitively unimpaired older adults self-report sleep is associated with brain amyloid beta (Aβ) accumulation.Across sleep characteristics, this relationship differs by apolipoprotein E (APOE) genotype.Sleep duration <6 hours is associated with faster brain Aβ accumulation in APOE ε4 carriers.Sleep efficiency < 65% is associated with faster brain Aβ accumulation in APOE ε4 non-carriers.Personalized sleep interventions should be studied for potential to slow Aβ accumulation.
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Slee MG, Rainey‐Smith SR, Villemagne VL, Doecke JD, Sohrabi HR, Taddei K, Ames D, Dore V, Maruff P, Laws SM, Masters CL, Rowe CC, Martins RN, Erickson KI, Brown BM. Physical activity and brain amyloid beta: A longitudinal analysis of cognitively unimpaired older adults. Alzheimers Dement 2024; 20:1350-1359. [PMID: 37984813 PMCID: PMC10917015 DOI: 10.1002/alz.13556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 10/13/2023] [Accepted: 10/23/2023] [Indexed: 11/22/2023]
Abstract
INTRODUCTION The current study evaluated the relationship between habitual physical activity (PA) levels and brain amyloid beta (Aβ) over 15 years in a cohort of cognitively unimpaired older adults. METHODS PA and Aβ measures were collected over multiple timepoints from 731 cognitively unimpaired older adults participating in the Australian Imaging, Biomarkers and Lifestyle (AIBL) Study of Aging. Regression modeling examined cross-sectional and longitudinal relationships between PA and brain Aβ. Moderation analyses examined apolipoprotein E (APOE) ε4 carriage impact on the PA-Aβ relationship. RESULTS PA was not associated with brain Aβ at baseline (β = -0.001, p = 0.72) or over time (β = -0.26, p = 0.24). APOE ε4 status did not moderate the PA-Aβ relationship over time (β = 0.12, p = 0.73). Brain Aβ levels did not predict PA trajectory (β = -54.26, p = 0.59). DISCUSSION Our study did not identify a relationship between habitual PA and brain Aβ levels. HIGHLIGHTS Physical activity levels did not predict brain amyloid beta (Aβ) levels over time in cognitively unimpaired older adults (≥60 years of age). Apolipoprotein E (APOE) ε4 carrier status did not moderate the physical activity-brain Aβ relationship over time. Physical activity trajectories were not impacted by brain Aβ levels.
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Poudel P, Frost SM, Eslick S, Sohrabi HR, Taddei K, Martins RN, Hone E. Hyperspectral Retinal Imaging as a Non-Invasive Marker to Determine Brain Amyloid Status. J Alzheimers Dis 2024; 100:S131-S152. [PMID: 39121128 DOI: 10.3233/jad-240631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2024]
Abstract
Background As an extension of the central nervous system (CNS), the retina shares many similarities with the brain and can manifest signs of various neurological diseases, including Alzheimer's disease (AD). Objective To investigate the retinal spectral features and develop a classification model to differentiate individuals with different brain amyloid levels. Methods Sixty-six participants with varying brain amyloid-β protein levels were non-invasively imaged using a hyperspectral retinal camera in the wavelength range of 450-900 nm in 5 nm steps. Multiple retina features from the central and superior views were selected and analyzed to identify their variability among individuals with different brain amyloid loads. Results The retinal reflectance spectra in the 450-585 nm wavelengths exhibited a significant difference in individuals with increasing brain amyloid. The retinal features in the superior view showed higher inter-subject variability. A classification model was trained to differentiate individuals with varying amyloid levels using the spectra of extracted retinal features. The performance of the spectral classification model was dependent upon retinal features and showed 0.758-0.879 accuracy, 0.718-0.909 sensitivity, 0.764-0.912 specificity, and 0.745-0.891 area under curve for the right eye. Conclusions This study highlights the spectral variation of retinal features associated with brain amyloid loads. It also demonstrates the feasibility of the retinal hyperspectral imaging technique as a potential method to identify individuals in the preclinical phase of AD as an inexpensive alternative to brain imaging.
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Wheelock MD, Strain JF, Mansfield P, Tu JC, Tanenbaum A, Preische O, Chhatwal JP, Cash DM, Cruchaga C, Fagan AM, Fox NC, Graff-Radford NR, Hassenstab J, Jack CR, Karch CM, Levin J, McDade EM, Perrin RJ, Schofield PR, Xiong C, Morris JC, Bateman RJ, Jucker M, Benzinger TLS, Ances BM, Eggebrecht AT, Gordon BA, Allegri R, Araki A, Barthelemy N, Bateman R, Bechara J, Benzinger T, Berman S, Bodge C, Brandon S, Brooks W, Brosch J, Buck J, Buckles V, Carter K, Cash D, Cash L, Chen C, Chhatwal J, Chrem P, Chua J, Chui H, Cruchaga C, Day GS, De La Cruz C, Denner D, Diffenbacher A, Dincer A, Donahue T, Douglas J, Duong D, Egido N, Esposito B, Fagan A, Farlow M, Feldman B, Fitzpatrick C, Flores S, Fox N, Franklin E, Friedrichsen N, Fujii H, Gardener S, Ghetti B, Goate A, Goldberg S, Goldman J, Gonzalez A, Gordon B, Gräber-Sultan S, Graff-Radford N, Graham M, Gray J, Gremminger E, Grilo M, Groves A, Haass C, Häsler L, Hassenstab J, Hellm C, Herries E, Hoechst-Swisher L, Hofmann A, Holtzman D, Hornbeck R, Igor Y, Ihara R, Ikeuchi T, Ikonomovic S, Ishii K, Jack C, Jerome G, Johnson E, Jucker M, Karch C, Käser S, Kasuga K, Keefe S, Klunk W, Koeppe R, Koudelis D, Kuder-Buletta E, Laske C, Lee JH, Levey A, Levin J, Li Y, Lopez O, Marsh J, Martinez R, Martins R, Mason NS, Masters C, Mawuenyega K, McCullough A, McDade E, Mejia A, Morenas-Rodriguez E, Mori H, Morris J, Mountz J, Mummery C, Nadkami N, Nagamatsu A, Neimeyer K, Niimi Y, Noble J, Norton J, Nuscher B, O'Connor A, Obermüller U, Patira R, Perrin R, Ping L, Preische O, Renton A, Ringman J, Salloway S, Sanchez-Valle R, Schofield P, Senda M, Seyfried N, Shady K, Shimada H, Sigurdson W, Smith J, Smith L, Snitz B, Sohrabi H, Stephens S, Taddei K, Thompson S, Vöglein J, Wang P, Wang Q, Weamer E, Xiong C, Xu J, Xu X. Brain network decoupling with increased serum neurofilament and reduced cognitive function in Alzheimer's disease. Brain 2023; 146:2928-2943. [PMID: 36625756 PMCID: PMC10316768 DOI: 10.1093/brain/awac498] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 11/21/2022] [Accepted: 12/12/2022] [Indexed: 01/11/2023] Open
Abstract
Neurofilament light chain, a putative measure of neuronal damage, is measurable in blood and CSF and is predictive of cognitive function in individuals with Alzheimer's disease. There has been limited prior work linking neurofilament light and functional connectivity, and no prior work has investigated neurofilament light associations with functional connectivity in autosomal dominant Alzheimer's disease. Here, we assessed relationships between blood neurofilament light, cognition, and functional connectivity in a cross-sectional sample of 106 autosomal dominant Alzheimer's disease mutation carriers and 76 non-carriers. We employed an innovative network-level enrichment analysis approach to assess connectome-wide associations with neurofilament light. Neurofilament light was positively correlated with deterioration of functional connectivity within the default mode network and negatively correlated with connectivity between default mode network and executive control networks, including the cingulo-opercular, salience, and dorsal attention networks. Further, reduced connectivity within the default mode network and between the default mode network and executive control networks was associated with reduced cognitive function. Hierarchical regression analysis revealed that neurofilament levels and functional connectivity within the default mode network and between the default mode network and the dorsal attention network explained significant variance in cognitive composite scores when controlling for age, sex, and education. A mediation analysis demonstrated that functional connectivity within the default mode network and between the default mode network and dorsal attention network partially mediated the relationship between blood neurofilament light levels and cognitive function. Our novel results indicate that blood estimates of neurofilament levels correspond to direct measurements of brain dysfunction, shedding new light on the underlying biological processes of Alzheimer's disease. Further, we demonstrate how variation within key brain systems can partially mediate the negative effects of heightened total serum neurofilament levels, suggesting potential regions for targeted interventions. Finally, our results lend further evidence that low-cost and minimally invasive blood measurements of neurofilament may be a useful marker of brain functional connectivity and cognitive decline in Alzheimer's disease.
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Chatterjee P, Vermunt L, Gordon BA, Pedrini S, Boonkamp L, Armstrong NJ, Xiong C, Singh AK, Li Y, Sohrabi HR, Taddei K, Molloy MP, Benzinger TL, Morris JC, Karch CM, Berman SB, Chhatwal J, Cruchaga C, Graff-Radford NR, Day GS, Farlow M, Fox NC, Goate AM, Hassenstab J, Lee JH, Levin J, McDade E, Mori H, Perrin RJ, Sanchez-Valle R, Schofield PR, Levey A, Jucker M, Masters CL, Fagan AM, Bateman RJ, Martins RN, Teunissen CE. Plasma glial fibrillary acidic protein in autosomal dominant Alzheimer's disease: Associations with Aβ-PET, neurodegeneration, and cognition. Alzheimers Dement 2023; 19:2790-2804. [PMID: 36576155 PMCID: PMC10300233 DOI: 10.1002/alz.12879] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 09/22/2022] [Accepted: 10/21/2022] [Indexed: 12/29/2022]
Abstract
BACKGROUND Glial fibrillary acidic protein (GFAP) is a promising candidate blood-based biomarker for Alzheimer's disease (AD) diagnosis and prognostication. The timing of its disease-associated changes, its clinical correlates, and biofluid-type dependency will influence its clinical utility. METHODS We evaluated plasma, serum, and cerebrospinal fluid (CSF) GFAP in families with autosomal dominant AD (ADAD), leveraging the predictable age at symptom onset to determine changes by stage of disease. RESULTS Plasma GFAP elevations appear a decade before expected symptom onset, after amyloid beta (Aβ) accumulation and prior to neurodegeneration and cognitive decline. Plasma GFAP distinguished Aβ-positive from Aβ-negative ADAD participants and showed a stronger relationship with Aβ load in asymptomatic than symptomatic ADAD. Higher plasma GFAP was associated with the degree and rate of neurodegeneration and cognitive impairment. Serum GFAP showed similar relationships, but these were less pronounced for CSF GFAP. CONCLUSION Our findings support a role for plasma GFAP as a clinical biomarker of Aβ-related astrocyte reactivity that is associated with cognitive decline and neurodegeneration. HIGHLIGHTS Plasma glial fibrillary acidic protein (GFAP) elevations appear a decade before expected symptom onset in autosomal dominant Alzheimer's disease (ADAD). Plasma GFAP was associated to amyloid positivity in asymptomatic ADAD. Plasma GFAP increased with clinical severity and predicted disease progression. Plasma and serum GFAP carried similar information in ADAD, while cerebrospinal fluid GFAP did not.
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Chatterjee P, Pedrini S, Doecke JD, Thota R, Villemagne VL, Doré V, Singh AK, Wang P, Rainey-Smith S, Fowler C, Taddei K, Sohrabi HR, Molloy MP, Ames D, Maruff P, Rowe CC, Masters CL, Martins RN. Plasma Aβ42/40 ratio, p-tau181, GFAP, and NfL across the Alzheimer's disease continuum: A cross-sectional and longitudinal study in the AIBL cohort. Alzheimers Dement 2023; 19:1117-1134. [PMID: 36574591 DOI: 10.1002/alz.12724] [Citation(s) in RCA: 88] [Impact Index Per Article: 44.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 05/22/2022] [Accepted: 05/23/2022] [Indexed: 12/29/2022]
Abstract
INTRODUCTION Plasma amyloid beta (Aβ)1-42/Aβ1-40 ratio, phosphorylated-tau181 (p-tau181), glial fibrillary acidic protein (GFAP), and neurofilament light (NfL) are putative blood biomarkers for Alzheimer's disease (AD). However, head-to-head cross-sectional and longitudinal comparisons of the aforementioned biomarkers across the AD continuum are lacking. METHODS Plasma Aβ1-42, Aβ1-40, p-tau181, GFAP, and NfL were measured utilizing the Single Molecule Array (Simoa) platform and compared cross-sectionally across the AD continuum, wherein Aβ-PET (positron emission tomography)-negative cognitively unimpaired (CU Aβ-, n = 81) and mild cognitive impairment (MCI Aβ-, n = 26) participants were compared with Aβ-PET-positive participants across the AD continuum (CU Aβ+, n = 39; MCI Aβ+, n = 33; AD Aβ+, n = 46) from the Australian Imaging, Biomarker & Lifestyle Flagship Study of Ageing (AIBL) cohort. Longitudinal plasma biomarker changes were also assessed in MCI (n = 27) and AD (n = 29) participants compared with CU (n = 120) participants. In addition, associations between baseline plasma biomarker levels and prospective cognitive decline and Aβ-PET load were assessed over a 7 to 10-year duration. RESULTS Lower plasma Aβ1-42/Aβ1-40 ratio and elevated p-tau181 and GFAP were observed in CU Aβ+, MCI Aβ+, and AD Aβ+, whereas elevated plasma NfL was observed in MCI Aβ+ and AD Aβ+, compared with CU Aβ- and MCI Aβ-. Among the aforementioned plasma biomarkers, for models with and without AD risk factors (age, sex, and apolipoprotein E (APOE) ε4 carrier status), p-tau181 performed equivalent to or better than other biomarkers in predicting a brain Aβ-/+ status across the AD continuum. However, for models with and without the AD risk factors, a biomarker panel of Aβ1-42/Aβ1-40, p-tau181, and GFAP performed equivalent to or better than any of the biomarkers alone in predicting brain Aβ-/+ status across the AD continuum. Longitudinally, plasma Aβ1-42/Aβ1-40, p-tau181, and GFAP were altered in MCI compared with CU, and plasma GFAP and NfL were altered in AD compared with CU. In addition, lower plasma Aβ1-42/Aβ1-40 and higher p-tau181, GFAP, and NfL were associated with prospective cognitive decline and lower plasma Aβ1-42/Aβ1-40, and higher p-tau181 and GFAP were associated with increased Aβ-PET load prospectively. DISCUSSION These findings suggest that plasma biomarkers are altered cross-sectionally and longitudinally, along the AD continuum, and are prospectively associated with cognitive decline and brain Aβ-PET load. In addition, although p-tau181 performed equivalent to or better than other biomarkers in predicting an Aβ-/+ status across the AD continuum, a panel of biomarkers may have superior Aβ-/+ status predictive capability across the AD continuum. HIGHLIGHTS Area under the curve (AUC) of p-tau181 ≥ AUC of Aβ42/40, GFAP, NfL in predicting PET Aβ-/+ status (Aβ-/+). AUC of Aβ42/40+p-tau181+GFAP panel ≥ AUC of Aβ42/40/p-tau181/GFAP/NfL for Aβ-/+. Longitudinally, Aβ42/40, p-tau181, and GFAP were altered in MCI versus CU. Longitudinally, GFAP and NfL were altered in AD versus CU. Aβ42/40, p-tau181, GFAP, and NfL are associated with prospective cognitive decline. Aβ42/40, p-tau181, and GFAP are associated with increased PET Aβ load prospectively.
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Chatterjee P, Doré V, Pedrini S, Krishnadas N, Thota R, Bourgeat P, Ikonomovic MD, Rainey-Smith SR, Burnham SC, Fowler C, Taddei K, Mulligan R, Ames D, Masters CL, Fripp J, Rowe CC, Martins RN, Villemagne VL. Plasma Glial Fibrillary Acidic Protein Is Associated with 18F-SMBT-1 PET: Two Putative Astrocyte Reactivity Biomarkers for Alzheimer's Disease. J Alzheimers Dis 2023; 92:615-628. [PMID: 36776057 PMCID: PMC10041433 DOI: 10.3233/jad-220908] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
BACKGROUND Astrocyte reactivity is an early event along the Alzheimer's disease (AD) continuum. Plasma glial fibrillary acidic protein (GFAP), posited to reflect astrocyte reactivity, is elevated across the AD continuum from preclinical to dementia stages. Monoamine oxidase-B (MAO-B) is also elevated in reactive astrocytes observed using 18F-SMBT-1 PET in AD. OBJECTIVE The objective of this study was to evaluate the association between the abovementioned astrocyte reactivity biomarkers. METHODS Plasma GFAP and Aβ were measured using the Simoa ® platform in participants who underwent brain 18F-SMBT-1 and Aβ-PET imaging, comprising 54 healthy control (13 Aβ-PET+ and 41 Aβ-PET-), 11 mild cognitively impaired (3 Aβ-PET+ and 8 Aβ-PET-) and 6 probable AD (5 Aβ-PET+ and 1 Aβ-PET-) individuals. Linear regressions were used to assess associations of interest. RESULTS Plasma GFAP was associated with 18F-SMBT-1 signal in brain regions prone to early Aβ deposition in AD, such as the supramarginal gyrus (SG), posterior cingulate (PC), lateral temporal (LT) and lateral occipital cortex (LO). After adjusting for age, sex, APOE ɛ4 genotype, and soluble Aβ (plasma Aβ 42/40 ratio), plasma GFAP was associated with 18F-SMBT-1 signal in the SG, PC, LT, LO, and superior parietal cortex (SP). On adjusting for age, sex, APOE ɛ4 genotype and insoluble Aβ (Aβ-PET), plasma GFAP was associated with 18F-SMBT-1 signal in the SG. CONCLUSION There is an association between plasma GFAP and regional 18F-SMBT-1 PET, and this association appears to be dependent on brain Aβ load.
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Sewell KR, Rainey-Smith SR, Peiffer J, Sohrabi HR, Taddei K, Ames D, Maruff P, Masters CL, Rowe CC, Martins RN, Erickson KI, Brown BM. The relationship between objective physical activity and change in cognitive function. Alzheimers Dement 2023. [PMID: 36656659 DOI: 10.1002/alz.12950] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Revised: 12/19/2022] [Accepted: 12/22/2022] [Indexed: 01/20/2023]
Abstract
INTRODUCTION The current study investigated the association between objectively measured physical activity and cognition in older adults over approximately 8 years. METHODS We utilized data from 199 cognitively unimpaired individuals from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study, aged ≥60. Actigraphy was used to measure physical activity (intensity, total activity, and energy expenditure) at baseline. Cognition was assessed using a comprehensive cognitive battery every 18-months. RESULTS Higher baseline energy expenditure predicted better episodic recall memory and global cognition over the follow-up period (p = 0.031; p = 0.047, respectively). Those with higher physical activity intensity and greater total activity also had better global cognition over time (both p = 0.005). Finally, higher total physical activity predicted improved episodic recall memory over time (p = 0.022). DISCUSSION These results suggest that physical activity can preserve cognition and that activity intensity may play an important role in this association. HIGHLIGHTS Greater total physical activity predicts preserved episodic memory and global cognition. Moderate intensity physical activity (>3.7 metabolic equivalents of task [MET]) predicts preserved global cognition. Expending > 373 kilocalories per day may benefit episodic memory and global cognition.
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Sewell KR, Rainey‐Smith S, Villemagne VL, Peiffer JJ, Sohrabi HR, Taddei K, Ames D, Maruff P, Laws SM, Masters CL, Rowe C, Martins RN, Erickson KI, Brown BM. Objectively measured physical activity and cognition in cognitively normal older adults: A longitudinal analysis of the Australian Imaging Biomarkers and Lifestyle (AIBL) study. Alzheimers Dement 2022. [DOI: 10.1002/alz.064392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Chatterjee P, Dore V, Pedrini S, Krishnadas N, Thota RN, Bourgeat P, Rainey‐Smith S, Burnham SC, Fowler C, Taddei K, Mulligan RS, Ames D, Masters CL, Fripp J, Rowe C, Martins RN, Villemagne VL. Plasma glial fibrillary acidic protein is associated with reactive astrogliosis assessed via
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F‐SMBT‐1 PET. Alzheimers Dement 2022. [DOI: 10.1002/alz.068749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Wang T, Huynh K, Giles C, Mellett NA, Duong T, Nguyen A, Lim WLF, Smith AAT, Olshansky G, Cadby G, Hung J, Hui J, Beilby J, Watts GF, Chatterjee P, Martins I, Laws SM, Bush AI, Rowe CC, Villemagne VL, Ames D, Masters CL, Taddei K, Doré V, Fripp J, Arnold M, Kastenmüller G, Nho K, Saykin AJ, Baillie R, Han X, Martins RN, Moses EK, Kaddurah‐Daouk R, Meikle PJ. APOE ε2 resilience for Alzheimer's disease is mediated by plasma lipid species: Analysis of three independent cohort studies. Alzheimers Dement 2022; 18:2151-2166. [PMID: 35077012 PMCID: PMC9787288 DOI: 10.1002/alz.12538] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 10/19/2021] [Accepted: 10/25/2021] [Indexed: 01/31/2023]
Abstract
INTRODUCTION The apolipoprotein E (APOE) genotype is the strongest genetic risk factor for late-onset Alzheimer's disease. However, its effect on lipid metabolic pathways, and their mediating effect on disease risk, is poorly understood. METHODS We performed lipidomic analysis on three independent cohorts (the Australian Imaging, Biomarkers and Lifestyle [AIBL] flagship study, n = 1087; the Alzheimer's Disease Neuroimaging Initiative [ADNI] 1 study, n = 819; and the Busselton Health Study [BHS], n = 4384), and we defined associations between APOE ε2 and ε4 and 569 plasma/serum lipid species. Mediation analysis defined the proportion of the treatment effect of the APOE genotype mediated by plasma/serum lipid species. RESULTS A total of 237 and 104 lipid species were associated with APOE ε2 and ε4, respectively. Of these 68 (ε2) and 24 (ε4) were associated with prevalent Alzheimer's disease. Individual lipid species or lipidomic models of APOE genotypes mediated up to 30% and 10% of APOE ε2 and ε4 treatment effect, respectively. DISCUSSION Plasma lipid species mediate the treatment effect of APOE genotypes on Alzheimer's disease and as such represent a potential therapeutic target.
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Pedrini S, Doecke JD, Hone E, Wang P, Thota R, Bush AI, Rowe CC, Dore V, Villemagne VL, Ames D, Rainey‐Smith S, Verdile G, Sohrabi HR, Raida MR, Taddei K, Gandy S, Masters CL, Chatterjee P, Martins R. Plasma high-density lipoprotein cargo is altered in Alzheimer's disease and is associated with regional brain volume. J Neurochem 2022; 163:53-67. [PMID: 36000528 PMCID: PMC9804612 DOI: 10.1111/jnc.15681] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/12/2022] [Accepted: 07/22/2022] [Indexed: 01/05/2023]
Abstract
Cholesterol levels have been repeatedly linked to Alzheimer's Disease (AD), suggesting that high levels could be detrimental, but this effect is likely attributed to Low-Density Lipoprotein (LDL) cholesterol. On the other hand, High-Density Lipoproteins (HDL) cholesterol levels have been associated with reduced brain amyloidosis and improved cognitive function. However, recent findings have suggested that HDL-functionality, which depends upon the HDL-cargo proteins associated with HDL, rather than HDL levels, appears to be the key factor, suggesting a quality over quantity status. In this report, we have assessed the HDL-cargo (Cholesterol, ApoA-I, ApoA-II, ApoC-I, ApoC-III, ApoD, ApoE, ApoH, ApoJ, CRP, and SAA) in stable healthy control (HC), healthy controls who will convert to MCI/AD (HC-Conv) and AD patients (AD). Compared to HC we observed an increased cholesterol/ApoA-I ratio in AD and HC-Conv, as well as an increased ApoD/ApoA-I ratio and a decreased ApoA-II/ApoA-I ratio in AD. Higher cholesterol/ApoA-I ratio was also associated with lower cortical grey matter volume and higher ventricular volume, while higher ApoA-II/ApoA-I and ApoJ/ApoA-I ratios were associated with greater cortical grey matter volume (and for ApoA-II also with greater hippocampal volume) and smaller ventricular volume. Additionally, in a clinical status-independent manner, the ApoE/ApoA-I ratio was significantly lower in APOE ε4 carriers and lowest in APOE ε4 homozygous. Together, these data indicate that in AD patients the composition of HDL is altered, which may affect HDL functionality, and such changes are associated with altered regional brain volumetric data.
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Shirzadi Z, Yau WYW, Schultz SA, Schultz AP, Scott MR, Goubran M, Mojiri-Forooshani P, Joseph-Mathurin N, Kantarci K, Preboske G, Wermer MJH, Jack C, Benzinger T, Taddei K, Sohrabi HR, Sperling RA, Johnson KA, Bateman RJ, Martins RN, Greenberg SM, Chhatwal JP. Progressive White Matter Injury in Preclinical Dutch Cerebral Amyloid Angiopathy. Ann Neurol 2022; 92:358-363. [PMID: 35670654 PMCID: PMC9391284 DOI: 10.1002/ana.26429] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Revised: 06/03/2022] [Accepted: 06/04/2022] [Indexed: 11/07/2022]
Abstract
Autosomal-dominant, Dutch-type cerebral amyloid angiopathy (D-CAA) offers a unique opportunity to develop biomarkers for pre-symptomatic cerebral amyloid angiopathy (CAA). We hypothesized that neuroimaging measures of white matter injury would be present and progressive in D-CAA prior to hemorrhagic lesions or symptomatic hemorrhage. In a longitudinal cohort of D-CAA carriers and non-carriers, we observed divergence of white matter injury measures between D-CAA carriers and non-carriers prior to the appearance of cerebral microbleeds and >14 years before the average age of first symptomatic hemorrhage. These results indicate that white matter disruption measures may be valuable cross-sectional and longitudinal biomarkers of D-CAA progression. ANN NEUROL 2022;92:358-363.
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Seneviratne R, Weinborn M, Badcock DR, Gavett BE, Laws M, Taddei K, Martins RN, Sohrabi HR. The Western Australia Olfactory Memory Test: Reliability and Validity in a Sample of Older Adults. Arch Clin Neuropsychol 2022; 37:1720-1734. [DOI: 10.1093/arclin/acac048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2022] [Indexed: 11/13/2022] Open
Abstract
Abstract
Objective
The Western Australia Olfactory Memory Test (WAOMT) is a newly developed test designed to meet a need for a comprehensive measure of olfactory episodic memory (OEM) for clinical and research applications.
Method
This study aimed to establish the psychometric properties of the WAOMT in a sample of 209 community-dwelling older adults. An independent sample of 27 test-naïve participants were recruited to assess test retest reliability (between 7 and 28 days). Scale psychometric properties were examined using item response theory methods, combined samples (final N = 241). Convergent validity was assessed by comparing performance on the WAOMT with a comprehensive neuropsychological battery of domains (verbal and visual episodic memory, and odor identification), as well as other neuropsychological skills. Based on previous literature, it was predicted that the WAOMT would be positively correlated with conceptually similar cognitive domains.
Results
The WAOMT is a psychometrically sound test with adequate reliability properties and demonstrated convergent validity with tests of verbal and episodic memory and smell identification. Patterns of performance highlight learning and memory characteristics unique to OEM (e.g., learning curves, cued and free recall).
Conclusion
Clinical and research implications include streamlining future versions of the WAOMT to ease patient and administrative burden, and the potential to reliably detect early neuropathological changes in healthy older adults with nonimpaired OEM abilities.
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Cadby G, Giles C, Melton PE, Huynh K, Mellett NA, Duong T, Nguyen A, Cinel M, Smith A, Olshansky G, Wang T, Brozynska M, Inouye M, McCarthy NS, Ariff A, Hung J, Hui J, Beilby J, Dubé MP, Watts GF, Shah S, Wray NR, Lim WLF, Chatterjee P, Martins I, Laws SM, Porter T, Vacher M, Bush AI, Rowe CC, Villemagne VL, Ames D, Masters CL, Taddei K, Arnold M, Kastenmüller G, Nho K, Saykin AJ, Han X, Kaddurah-Daouk R, Martins RN, Blangero J, Meikle PJ, Moses EK. Comprehensive genetic analysis of the human lipidome identifies loci associated with lipid homeostasis with links to coronary artery disease. Nat Commun 2022; 13:3124. [PMID: 35668104 PMCID: PMC9170690 DOI: 10.1038/s41467-022-30875-7] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 05/17/2022] [Indexed: 12/26/2022] Open
Abstract
We integrated lipidomics and genomics to unravel the genetic architecture of lipid metabolism and identify genetic variants associated with lipid species putatively in the mechanistic pathway for coronary artery disease (CAD). We quantified 596 lipid species in serum from 4,492 individuals from the Busselton Health Study. The discovery GWAS identified 3,361 independent lipid-loci associations, involving 667 genomic regions (479 previously unreported), with validation in two independent cohorts. A meta-analysis revealed an additional 70 independent genomic regions associated with lipid species. We identified 134 lipid endophenotypes for CAD associated with 186 genomic loci. Associations between independent lipid-loci with coronary atherosclerosis were assessed in ∼456,000 individuals from the UK Biobank. Of the 53 lipid-loci that showed evidence of association (P < 1 × 10-3), 43 loci were associated with at least one lipid endophenotype. These findings illustrate the value of integrative biology to investigate the aetiology of atherosclerosis and CAD, with implications for other complex diseases.
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Morenas-Rodríguez E, Li Y, Nuscher B, Franzmeier N, Xiong C, Suárez-Calvet M, Fagan AM, Schultz S, Gordon BA, Benzinger TLS, Hassenstab J, McDade E, Feederle R, Karch CM, Schlepckow K, Morris JC, Kleinberger G, Nellgard B, Vöglein J, Blennow K, Zetterberg H, Ewers M, Jucker M, Levin J, Bateman RJ, Haass C, Allegri R, Araki A, Barthelemy N, Bechara J, Berman S, Bodge C, Brandon S, Brooks W(B, Brosch J, Buck J, Buckles V, Carter K, Cash L, Chen C, Chhatwal J, Chrem P, Chua J, Chui H, Cruchaga C, Day GS, De La Cruz C, Denner D, Diffenbacher A, Dincer A, Donahue T, Douglas J, Duong D, Egido N, Esposito B, Farlow M, Feldman B, Fitzpatrick C, Flores S, Fox N, Franklin E, Friedrichsen N, Fujii H, Gardener S, Ghetti B, Goate A, Goldberg S, Goldman J, Gonzalez A, Gräber-Sultan S, Graff-Radford N, Graham M, Gray J, Gremminger E, Grilo M, Groves A, Häsler L, Hellm C, Herries E, Hoechst-Swisher L, Hofmann A, Holtzman D, Hornbeck R, Igor Y, Ihara R, Ikeuchi T, Ikonomovic S, Ishii K, Jack C, Jerome G, Johnson E, Käser S, Kasuga K, Keefe S, Klunk W(B, Koeppe R, Koudelis D, Kuder-Buletta E, Laske C, Levey A, Lopez O, Marsh J, Martinez R, Martins R, Mason NS, Masters C, Mawuenyega K, McCullough A, Mejia A, MountzMD J, Mummery C, Nadkarni N, Nagamatsu A, Neimeyer K, Niimi Y, Noble J, Norton J, Nuscher B, O'Connor A, Obermüller U, Patira R, Perrin R, Ping L, Preische O, Renton A, Ringman J, Salloway S, Schofield P, Senda M, Seyfried N, Shady K, Shimada H, Sigurdson W, Smith J, Smith L, Snitz B, Sohrabi H, Stephens S, Taddei K, Thompson S, Wang P, Wang Q, Weamer E, Xu J, Xu X. Soluble TREM2 in CSF and its association with other biomarkers and cognition in autosomal-dominant Alzheimer's disease: a longitudinal observational study. Lancet Neurol 2022; 21:329-341. [PMID: 35305339 PMCID: PMC8926925 DOI: 10.1016/s1474-4422(22)00027-8] [Citation(s) in RCA: 98] [Impact Index Per Article: 32.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 01/05/2022] [Accepted: 01/10/2022] [Indexed: 02/08/2023]
Abstract
BACKGROUND Therapeutic modulation of TREM2-dependent microglial function might provide an additional strategy to slow the progression of Alzheimer's disease. Although studies in animal models suggest that TREM2 is protective against Alzheimer's pathology, its effect on tau pathology and its potential beneficial role in people with Alzheimer's disease is still unclear. Our aim was to study associations between the dynamics of soluble TREM2, as a biomarker of TREM2 signalling, and amyloid β (Aβ) deposition, tau-related pathology, neuroimaging markers, and cognitive decline, during the progression of autosomal dominant Alzheimer's disease. METHODS We did a longitudinal analysis of data from the Dominantly Inherited Alzheimer Network (DIAN) observational study, which includes families with a history of autosomal dominant Alzheimer's disease. Participants aged over 18 years who were enrolled in DIAN between Jan 1, 2009, and July 31, 2019, were categorised as either carriers of pathogenic variants in PSEN1, PSEN2, and APP genes (n=155) or non-carriers (n=93). We measured amounts of cleaved soluble TREM2 using a novel immunoassay in CSF samples obtained every 2 years from participants who were asymptomatic (Clinical Dementia Rating [CDR]=0) and annually for those who were symptomatic (CDR>0). CSF concentrations of Aβ40, Aβ42, total tau (t-tau), and tau phosphorylated on threonine 181 (p-tau) were measured by validated immunoassays. Predefined neuroimaging measurements were total cortical uptake of Pittsburgh compound B PET (PiB-PET), cortical thickness in the precuneus ascertained by MRI, and hippocampal volume determined by MRI. Cognition was measured using a validated cognitive composite (including DIAN word list test, logical memory delayed recall, digit symbol coding test [total score], and minimental status examination). We based our statistical analysis on univariate and bivariate linear mixed effects models. FINDINGS In carriers of pathogenic variants, a high amyloid burden at baseline, represented by low CSF Aβ42 (β=-4·28 × 10-2 [SE 0·013], p=0·0012), but not high cortical uptake in PiB-PET (β=-5·51 × 10-3 [0·011], p=0·63), was the only predictor of an augmented annual rate of subsequent increase in soluble TREM2. Augmented annual rates of increase in soluble TREM2 were associated with a diminished rate of decrease in amyloid deposition, as measured by Aβ42 in CSF (r=0·56 [0·22], p=0·011), in presymptomatic carriers of pathogenic variants, and with diminished annual rate of increase in PiB-PET (r=-0·67 [0·25], p=0·0060) in symptomatic carriers of pathogenic variants. Presymptomatic carriers of pathogenic variants with annual rates of increase in soluble TREM2 lower than the median showed a correlation between enhanced annual rates of increase in p-tau in CSF and augmented annual rates of increase in PiB-PET signal (r=0·45 [0·21], p=0·035), that was not observed in those with rates of increase in soluble TREM2 higher than the median. Furthermore, presymptomatic carriers of pathogenic variants with rates of increase in soluble TREM2 above or below the median had opposite associations between Aβ42 in CSF and PiB-PET uptake when assessed longitudinally. Augmented annual rates of increase in soluble TREM2 in presymptomatic carriers of pathogenic variants correlated with decreased cortical shrinkage in the precuneus (r=0·46 [0·22]), p=0·040) and diminished cognitive decline (r=0·67 [0·22], p=0·0020). INTERPRETATION Our findings in autosomal dominant Alzheimer's disease position the TREM2 response within the amyloid cascade immediately after the first pathological changes in Aβ aggregation and further support the role of TREM2 on Aβ plaque deposition and compaction. Furthermore, these findings underpin a beneficial effect of TREM2 on Aβ deposition, Aβ-dependent tau pathology, cortical shrinkage, and cognitive decline. Soluble TREM2 could, therefore, be a key marker for clinical trial design and interpretation. Efforts to develop TREM2-boosting therapies are ongoing. FUNDING German Research Foundation, US National Institutes of Health.
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Pedrini S, Chatterjee P, Nakamura A, Tegg M, Hone E, Rainey-Smith SR, Rowe CC, Dore V, Villemagne VL, Ames D, Kaneko N, Gardener SL, Taddei K, Fernando B, Martins I, Bharadwaj P, Sohrabi HR, Masters CL, Brown B, Martins RN. The Association Between Alzheimer's Disease-Related Markers and Physical Activity in Cognitively Normal Older Adults. Front Aging Neurosci 2022; 14:771214. [PMID: 35418852 PMCID: PMC8996810 DOI: 10.3389/fnagi.2022.771214] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 01/13/2022] [Indexed: 11/13/2022] Open
Abstract
Previous studies have indicated that physical activity may be beneficial in reducing the risk for Alzheimer's disease (AD), although the underlying mechanisms are not fully understood. The goal of this study was to evaluate the relationship between habitual physical activity levels and brain amyloid deposition and AD-related blood biomarkers (i.e., measured using a novel high-performance mass spectrometry-based assay), in apolipoprotein E (APOE) ε4 carriers and noncarriers. We evaluated 143 cognitively normal older adults, all of whom had brain amyloid deposition assessed using positron emission tomography and had their physical activity levels measured using the International Physical Activity Questionnaire (IPAQ). We observed an inverse correlation between brain amyloidosis and plasma beta-amyloid (Aβ)1−42 but found no association between brain amyloid and plasma Aβ1−40 and amyloid precursor protein (APP)669−711. Additionally, higher levels of physical activity were associated with lower plasma Aβ1−40, Aβ1−42, and APP669−711 levels in APOE ε4 noncarriers. The ratios of Aβ1−40/Aβ1−42 and APP669−711/Aβ1−42, which have been associated with higher brain amyloidosis in previous studies, differed between APOE ε4 carriers and non-carriers. Taken together, these data indicate a complex relationship between physical activity and brain amyloid deposition and potential blood-based AD biomarkers in cognitively normal older adults. In addition, the role of APOE ε4 is still unclear, and more studies are necessary to bring further clarification.
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Gardener SL, Rainey-Smith SR, Villemagne VL, Fripp J, Doré V, Bourgeat P, Taddei K, Fowler C, Masters CL, Maruff P, Rowe CC, Ames D, Martins RN. Higher Coffee Consumption Is Associated With Slower Cognitive Decline and Less Cerebral Aβ-Amyloid Accumulation Over 126 Months: Data From the Australian Imaging, Biomarkers, and Lifestyle Study. Front Aging Neurosci 2021; 13:744872. [PMID: 34867277 PMCID: PMC8641656 DOI: 10.3389/fnagi.2021.744872] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 09/23/2021] [Indexed: 12/19/2022] Open
Abstract
Background: Worldwide, coffee is one of the most popular beverages consumed. Several studies have suggested a protective role of coffee, including reduced risk of Alzheimer's disease (AD). However, there is limited longitudinal data from cohorts of older adults reporting associations of coffee intake with cognitive decline, in distinct domains, and investigating the neuropathological mechanisms underpinning any such associations. Methods: The aim of the current study was to investigate the relationship between self-reported habitual coffee intake, and cognitive decline assessed using a comprehensive neuropsychological battery in 227 cognitively normal older adults from the Australian Imaging, Biomarkers, and Lifestyle (AIBL) study, over 126 months. In a subset of individuals, we also investigated the relationship between habitual coffee intake and cerebral Aβ-amyloid accumulation (n = 60) and brain volumes (n = 51) over 126 months. Results: Higher baseline coffee consumption was associated with slower cognitive decline in executive function, attention, and the AIBL Preclinical AD Cognitive Composite (PACC; shown reliably to measure the first signs of cognitive decline in at-risk cognitively normal populations), and lower likelihood of transitioning to mild cognitive impairment or AD status, over 126 months. Higher baseline coffee consumption was also associated with slower Aβ-amyloid accumulation over 126 months, and lower risk of progressing to "moderate," "high," or "very high" Aβ-amyloid burden status over the same time-period. There were no associations between coffee intake and atrophy in total gray matter, white matter, or hippocampal volume. Discussion: Our results further support the hypothesis that coffee intake may be a protective factor against AD, with increased coffee consumption potentially reducing cognitive decline by slowing cerebral Aβ-amyloid accumulation, and thus attenuating the associated neurotoxicity from Aβ-amyloid-mediated oxidative stress and inflammatory processes. Further investigation is required to evaluate whether coffee intake could be incorporated as a modifiable lifestyle factor aimed at delaying AD onset.
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Gardener SL, Rainey‐Smith SR, Villemagne VLL, Fripp J, Dore V, Bourgeat P, Taddei K, Masters CL, Maruff PT, Rowe CC, Ames D, Martins RN. Higher coffee consumption is associated with slower cognitive decline and Aβ‐amyloid accumulation over 126 months: Data from the AIBL study. Alzheimers Dement 2021. [DOI: 10.1002/alz.051574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Sewell KR, Rainey‐Smith SR, Villemagne VLL, Peiffer JJ, Sohrabi HR, Taddei K, Ames D, Maruff PT, Laws SM, Masters CL, Rowe CC, Martins RN, Erickson KI, Brown BM. How lifestyle shapes the brain: Associations between physical activity, sleep, beta‐amyloid and cognitive function in older adults. Alzheimers Dement 2021. [DOI: 10.1002/alz.051223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chatterjee P, Fagan AM, Xiong C, McKay M, Bhatnagar A, Wu Y, Singh AK, Taddei K, Martins I, Gardener SL, Molloy MP, Multhaup G, Masters CL, Schofield PR, Benzinger TLS, Morris JC, Bateman RJ, Greenberg SM, Wermer MJH, van Buchem MA, Sohrabi HR, Martins RN. Presymptomatic Dutch-Type Hereditary Cerebral Amyloid Angiopathy-Related Blood Metabolite Alterations. J Alzheimers Dis 2021; 79:895-903. [PMID: 33361604 DOI: 10.3233/jad-201267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Cerebral amyloid angiopathy (CAA) is one of the major causes of intracerebral hemorrhage and vascular dementia in older adults. Early diagnosis will provide clinicians with an opportunity to intervene early with suitable strategies, highlighting the importance of pre-symptomatic CAA biomarkers. OBJECTIVE Investigation of pre-symptomatic CAA related blood metabolite alterations in Dutch-type hereditary CAA mutation carriers (D-CAA MCs). METHODS Plasma metabolites were measured using mass-spectrometry (AbsoluteIDQ® p400 HR kit) and were compared between pre-symptomatic D-CAA MCs (n = 9) and non-carriers (D-CAA NCs, n = 8) from the same pedigree. Metabolites that survived correction for multiple comparisons were further compared between D-CAA MCs and additional control groups (cognitively unimpaired adults). RESULTS 275 metabolites were measured in the plasma, 22 of which were observed to be significantly lower in theD-CAAMCs compared to D-CAA NCs, following adjustment for potential confounding factors age, sex, and APOE ε4 (p < 00.05). After adjusting for multiple comparisons, only spermidine remained significantly lower in theD-CAAMCscompared to theD-CAA NCs (p < 0.00018). Plasma spermidine was also significantly lower in D-CAA MCs compared to the cognitively unimpaired young adult and older adult groups (p < 0.01). Spermidinewas also observed to correlate with CSF Aβ40 (rs = 0.621, p = 0.024), CSF Aβ42 (rs = 0.714, p = 0.006), and brain Aβ load (rs = -0.527, p = 0.030). CONCLUSION The current study provides pilot data on D-CAA linked metabolite signals, that also associated with Aβ neuropathology and are involved in several biological pathways that have previously been linked to neurodegeneration and dementia.
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