bluuebunny/crossref_metadata_2025_split huggingface dataset:
CSF total tau is more closely associated with synaptic dysfunction than overt neurodegeneration
Authors: Soares Carolina , Bellaver Bruna , Ferreira Pamela C.L. , Povala Guilherme , Aguzzoli Cristiano Schaffer , Ferrari‐Souza João Pedro , Zalzale Hussein , Lussier Firoza Z , Rohden Francieli , Abbas Sarah , Lemaire Peter Charles , Leffa Douglas Teixeira , Cabrera Arlec , Therriault Joseph , Benedet Andrea Lessa , Tissot Cécile , Servaes Stijn , Macedo Arthur C. , Vermeiren Marie , Bezgin Gleb , Kang Min Su , Stevenson Jenna , Rahmouni Nesrine , Pallen Vanessa , Cohen Annie , Lopez Oscar L. , Tudorascu Dana , Klunk William E , Villemagne Victor L , Soucy Jean‐Paul , Gauthier Serge , Souza Diogo O. , Karikari Thomas K , Ashton Nicholas J. , Zetterberg Henrik , Blennow Kaj , Rosa‐Neto Pedro , Zimmer Eduardo R , Pascoal Tharick A. 
Published: December 2023

AbstractBackgroundCSF total tau (t‐tau) is postulated as a marker of neuronal degeneration in the ATN criteria. Here, we hypothesize that CSF t‐tau is more closely related to synaptic loss than over neurodegeneration.MethodWe evaluated 128 older individuals (75 CU,33 MCI,20 AD) in the TRIAD cohort (McGill, Canada) with CSF t‐tau, SNAP25long and Neurofilament Light (NfL), Amyloid‐beta (Aβ) positron emission tomography and magnetic resonance imaging, and clinical assessments. We used increased SNAP25long as an index of synaptic dysfunction (S+) and reduced hippocampal volume as neurodegeneration (N+). S and N positivity were determined using a cutoff anchored in young CU individuals. Linear regression models were used to test the association between CSF t‐tau, SNAP25long and NfL levels and hippocampal volume, adjusted for age, sex, and cognitive status. ANCOVA was employed to inspect CSF t‐tau levels across the groups 1) S‐N‐; 2) S+N‐; 3) S‐N+; 4) S+N+, adjusted for age, sex, cognitive status, and Aβ burden.ResultWe found that a model with the addition of SNAP25long to the covariates explained 65% of the variance (p‐value<0.0001) of CSF t‐tau. Alternatively, hippocampal volume (R2 = 0.2187; p‐value<0.0001) and NfL (R2 = 0.3671; p‐value<0.0001) alone or in combination explained less than 40% of the variance of CSF t‐tau (R2 = 0.3597; p‐value<0.0001) (Figure 1). Interestingly, we observed an increase of CSF t‐tau in the S+N‐ group but not in the S‐N+, further supporting that CSF t‐tau is abnormal in the presence of synaptic dysfunction rather than neurodegeneration. Additionally, Loess regression lines confirm a larger magnitude of change of synaptic dysfunction as a function of t‐tau, compared with neurodegeneration (Figure 3).
ConclusionOur results suggest that CSF t‐tau may reflect synaptic loss rather than neuronal degeneration. This has implications for the interpretability of results obtained with CSF t‐tau in biomarker studies.
SORL1 regulates tau trafficking
Authors: Cooper Joanna M , Lathuiliere Aurelien , Su Enming J , Jo Youhwa , Migliorini Mary , Lawrence Daniel A , Hyman Bradley T. , Strickland Dudley K 
Published: December 2023

AbstractBackgroundWhile LRP1 is a cellular receptor that mediates tau uptake and potentiates tau seeding, we observed LRP1‐independent uptake of tau in LRP1‐genetically deficient cells and hypothesized that the sortilin‐related receptor (SORL1) could also be involved in tau processing.MethodSurface plasmon resonance was used to assess tau binding to SORL1. 125I‐labelled tau uptake assays were used to investigate the role of SORL1 in endocytosis. The P301S FRET biosensor was used to assess SORL1’s role in cytosolic tau seeding, using both WT and AD‐associated mutations in the SORL1 gene (G511R and N1358S). Confocal microscopy was used to investigate colocalization and intracellular trafficking of tau and SORL1. Finally, we investigated the impact of SORL1 on tau processing in vivo by injecting human pathogenic tau isolated from AD patients into the hippocampus of SORL1 knockout vs wildtype mice and analyzing via immunohistochemistry.ResultWe confirmed high‐affinity binding of tau to SORL1 and found that fluorescently labeled tau colocalizes with overexpressed SORL1 in H4 neuroglioma cells. When we knocked down SORL1 expression using siRNA in H4 cells, we observed a significant increase in the LRP1‐mediated degradation of 125I‐labeled tau, revealing that SORL1 directs tau away from lysosomal degradative pathways. To determine if this occurs in vivo, we injected pathogenic forms of human tau into the hippocampal region of WT and SORL1‐deficient mice. Two days following injection, preliminary results suggest less human tau retention in the brains of SORL1‐deficient mice when compared to WT controls. Together, these data suggest that SORL1 may have a dual function in tau metabolism: impacting both uptake of tau, and trafficking of pathogenic tau to lysosomes. We also found that SORL1 promotes cytosolic tau seeding induced by pathogenic forms of tau. The AD‐associated N1358S mutation SORL1 gene demonstrated a significant increase in tau seeding when compared with WT SORL1.ConclusionThese studies identify SORL1 as a sorting receptor for tau that contributes to seeding of pathogenic tau. Furthermore, they indicated that SORL1 directs tau away from lysosomal degradation pathways, and identify promotion of tau seeding as a potential mechanism by which the SORL1 N1358S mutation contributes to AD.
Neuropathological correlates of neuropsychiatric symptoms in the Brains for Dementia Research study
Authors: Lawson Anna , Matthews Fiona E , Erskine Daniel , Hamilton Calum Alexander , Thomas Alan J 
Published: December 2023

AbstractBackgroundNeuropsychiatric symptoms are a common feature of many dementia syndromes, and are frequently associated with poor clinical prognosis, reduction in quality of life, earlier institutionalisation, greater disability, and increased caregiver distress, particularly during later stages of disease. It has also been postulated that NPS may occur during prodromal stages of dementia, preceding or alongside early cognitive symptoms. Clinical profiles of dementia are both heterogenous and intersecting, which may reflect that up to 90% of cases have multiple pathologies post‐mortem. Comprehensive clinicopathological studies of neuropsychiatric symptoms in dementia are lacking, thus this study sought to investigate potential neuropsychiatric profiles resulting from mixed underlying pathology.MethodThis analysis aimed to identify pathological correlations of neuropsychiatric symptoms and included 840 post‐mortem brains donated to the Brains for Dementia Research project, a longitudinal study with post‐mortem neuropathological assessment across several brain banks, between 2008 and 2020. Patterns of neuropsychiatric symptoms were compared between pathology subtypes using clinical data including the Neuropsychiatric Inventory (NPI‐Q) and Clinical Dementia Rating scale, and neuropathological assessment of degenerative pathologies and vascular features. Confirmatory factor analysis was used to identify latent variables for psychosis, mood, and behaviour. Associations between pathological variables assessed at autopsy and neuropsychiatric features during life were explored using bivariate and multivariate statistical methods.ResultAlmost 80% of the 494 dementia cases included had at least one neuropsychiatric symptom across the course of disease. Apathy (51.2%) and aggression (41.7%) were the most prevalent neuropsychiatric features across all dementia subtypes. Preliminary results indicate that different underlying pathologies, including neurodegenerative pathologies (amyloid, neurofibrillary tangles, Lewy bodies, TDP‐43 inclusions) and vascular features may be associated with increased likelihood of specific neuropsychiatric symptoms, such as psychosis, mood and behaviour, during life. Co‐occurring substantial AD and Lewy body pathology was associated with the presence of anxiety, depression, and aberrant motor activity during life. AD in the absence of substantial Lewy body pathology, was associated with agitation, apathy, and disinhibition. Lewy body pathology, in the absence of substantial AD pathology, was associated with hallucinations, depression and sleep disturbances.ConclusionThe interaction of multiple pathologies may contribute to differing neuropsychiatric profiles during life.
The Many Faces of Dementia in Canada: Findings from the Landmark Study
Authors: Armstrong Joshua J. , Sivananthan Saskia , Guimond Josée , Stiff David , Smetanin Paul 
Published: December 2023

AbstractBackgroundWith the rapidly increasing size of the dementia population, it is important to get a better understanding of the similarities and differences that are found across the people living with dementia. This work expands on the first report from the Landmark Study and takes a closer look at the many faces of dementia in Canada by highlighting some of the diversity that is found within the national projections for dementia.MethodUsing the Canadian Centre for Economic Analysis’s socio‐economic statistical analysis platform, a simulation model was developed using demographic characteristics and risk factors for dementia to forecast the numbers of people living with dementia in Canada from 2020‐2050. Here, we will examine findings related to sex, Indigenous Peoples, ethnic origins, and young‐onset dementia.ResultIn 2020, 61.3% of dementia diagnoses were in females and this sex ratio is projected to stay relatively constant over the three decades. By 2050, 1.08 million females and 637,000 males are projected to be living with dementia. For Indigenous Peoples of Canada, dementia numbers are estimated to increase by 273% (2020: 10,800; 2050: 40,300). By 2050, the ethnic background of people living with dementia will be quite different than today. People of Asian origin will increase from 8% of people living with dementia in 2020 to 24% by 2050. The changes are driven both by future immigration, and by people who have already immigrated to Canada in the past few decades. While most cases of dementia are found in older age groups, by 2050, the Landmark Study projects that there could be over 40,000 people under the age of 65 living with dementia in Canada, compared to the 28,000 in 2020.ConclusionThis study illustrates the changing landscape of dementia in Canada. The characteristics examined in this study, as well as other distinctions between people, can profoundly affect the way in which dementia is experienced and their care needs. When it comes to these differences, we propose that the best way forward is to examine them, generate evidence, listen closely to the recommendations that come from these communities, and collectively advocate for systemic change.
Role of primary cerebrovascular cilia in the pathogenesis of blood pressure and Alzheimer’s disease manifestations
Authors: Aboualaiwi Wissam 
Published: December 2023

AbstractBackgroundPrimary cilia are solitary membrane‐bound organelles emanating from the apical surface of most mammalian cells. They serve as sensory organelles sampling the extracellular environment and reprogramming the transcriptional machinery in response to changes in fluid flow. Ciliopathies, a group of genetic disorders characterized by disrupted cilia structure and/or function, share common phenotypes such as vascular dysfunction and cognitive impairment. Ciliopathies present with a broad range of clinical symptoms, including hypertension (HTN), developmental delays and cognitive and memory deficits, symptoms also observed in Alzheimer’s Disease (AD). This suggests that cilia may house signaling cascades critical for vascular integrity and learning and memory and may also be important contributors to AD and HTN. Therefore, investigation of cilia function in the vascular system may reveal cilia‐modulating mechanisms in neurodevelopmental processes. We propose a bold idea to look at the pathophysiological roles of cerebrovascular ciliary receptors in BP and AD.MethodImmunofluorescence of human brain endothelial cells (HBECs) were employed to study AChM3R localization and its downstream effectors. Cilia length and function (eNOS activation) studies were carried out to examine if mAChRs activation would enhance cilia structure and function. siRNA‐mediated knockdown of Tulp‐3 was performed to block AChM3R trafficking to primary cilia and study its activity. HBECs were exposed to synthetic Aβ to study their effect on cilia structure and ciliogenesis. Vascular‐specific cilia and AChM3R knockout mice were generated to study blood pressure and AD manifestations.ResultWe discovered that AChM3R, PIP2, and eNOS localize to primary cilia. mAChR‐specific activation increases cilia length in HBECs and cilia formation in cilialess Tg737 cells and was also associated with an increase in eNOS activity. Exposure to 2.5 μM human Aβ42 resulted in significant reduction in primary cilia length and ciliation percentage. RNAi‐mediated knockdown of Tulp3 caused a significant decrease in AChM3R trafficking to the cilia, associated with altered activity, suggesting that ciliary AChM3R localization is important for its activity. Vascular‐specific AChM3R and Tg737 KO mice developed high BP. Preliminary studies to examine cognitive function indicate altered cognitive function associated cerebrovascular cilia dysfunction.ConclusionPrimary cilia play an important sensory role for the regulation of blood pressure and cognitive function.
Participating in leisure time physical activity across adulthood and later‐life brain health: 30 years follow‐up in 1946 British Birth Cohort
Authors: James Sarah‐Naomi , Nicholas Jennifer M , Chiou Yu‐Jie , Parker Thomas D , Lu Kirsty , Murray‐Smith Heidi , Cash David M , Malone Ian B , Sudre Carole H , Keshavan Ashvini , Coath William , Flores‐Guerrero Jose L , Orini Michele , Almeida‐Meza Pamela , Fox Nick C , Richards Marcus , Schott Jonathan M 
Published: December 2023

AbstractBackgroundWe assess if, and at which ages during 30 years of adulthood, undertaking leisure time physical activity (LTPA) is associated with brain health at age 70, and to what extent brain health metrics explain the positive association between LTPA and later‐life cognition.MethodParticipants from the British 1946 birth cohort prospectively reported LTPA five times between ages 36 and 69. Metrics were categorised into: not active (no participation/month); active (participated once or more/month); and summed. Participants underwent 18F‐florbetapir Aβ‐PET and MRI at age 70 (n = 468, 49% female). Regression analyses examined associations between LTPA metrics and later‐life brain health including Aβ‐PET, TIV‐adjusted brain, hippocampal and log‐transformed‐white matter hyperintensity (WMH) volume, adjusting for sex, scan age, childhood cognition, education, and childhood socioeconomic position. Effect modification by sex and APOE‐ε4 were examined. The relationship between cumulative LPTA and later‐life cognition (Addenbrooke’s cognitive Examination (ACE‐III)) was assessed adjusting for brain health measures.ResultParticipation in LTPA was associated with better brain health at age 70. For brain volume and WMH volume, the strongest associations were with LTPA at age 69 (Figure 1). Being active in one or more period across adulthood was linked to larger hippocampal volume (Figure 1); this relationship was modified by APOE‐ε4 (p<0.01), with a stronger effect shown in ε4 carriers (Figure 2). LTPA at age 43 was also associated with larger hippocampal volumes. There was no evidence of associations with amyloid status. The positive association between cumulative LTPA and better cognition was not attenuated by any of the brain health measures (Figure 3).ConclusionWe provide evidence that LTPA across adulthood is linked to brain health at age 70; being active throughout adulthood was associated with larger hippocampal volume, particularly in APOE ε4 carriers; and being active in later‐life was linked to less WMH and larger brain volume at age 70. However, these brain health metrics did not explain the relationship between LPTA and better cognitive scores, suggesting that these pathways may not underlie the inferred cognitive benefit at this age. Our findings warrant further research to shed light on the mechanisms of physical activity as a potential disease‐modifying intervention of brain health.
Aorta‐carotid hemodynamics and cognitive function in the U.S. POINTER Neurovascular ancillary study
Authors: Brinkley Tina E , Mitchell Gary F , Garcia Katelyn R , Leng Xiaoyan , Tegeler Charles H , Baker Laura D , Snyder Heather M , Bailey Margie J , Shaltout Hossam A 
Published: December 2023

AbstractBackgroundThe brain is particularly sensitive to excessive pressure and flow pulsatility. Disproportionate stiffening of the aorta can reduce wave reflection at the aorta‐carotid interface and facilitate transmission of excessive pulsatile energy into the cerebral microcirculation, leading to impaired cognitive function. The U.S. POINTER Neurovascular (POINTER‐NV) ancillary study is an ongoing study designed to evaluate vascular structure and function in participants from the U.S. POINTER trial. Here we describe the baseline characteristics of the POINTER‐NV participants, focusing on aortic and carotid variables and their association with cognitive function.MethodUltrasound and tonometry were used to assess aortic and carotid measures. Hemodynamic and structural variables were compared according to cognitive status using the baseline Clinical Dementia Rating Scale Sum of Boxes (CDR‐SB) score categorized as normal (CDR‐SB = 0) or possibly impaired (CDR‐SB>0). Linear regression was used to assess cross‐sectional associations between aortic and carotid variables and composite scores for global cognition, executive function, memory, and processing speed, with and without adjustment for age, sex, race, and ethnicity.ResultAortic and carotid hemodynamics were available for 165 POINTER‐NV participants (mean age: 67.9±5.1 years, 70% female, 37% people of color). A large proportion of the participants had evidence of subclinical cardiovascular disease based on a carotid intima‐media thickness ≥1.0 mm (n = 109/165, 66.1%) or increased aortic stiffness based on a carotid‐femoral pulse wave velocity >10 m/s (n = 70/131, 53.4%). There were no significant differences in aortic or carotid structure and function between participants with normal cognition (n = 109) and those with possible cognitive impairment (n = 56). Higher carotid‐femoral pulse wave velocity was associated with lower global cognition, executive function, and processing speed, even after adjustment for age, sex, race, and ethnicity (all p<0.05). Although there was some suggestion that higher carotid pulsatility, higher carotid transmission, and lower aorta‐carotid reflection may be associated with worse cognition, these associations were not consistent across cognitive domains and did not hold up after covariate adjustment.ConclusionAge‐related changes in vascular structure and function can promote cognitive decline and dementia. Our data are consistent with prior evidence suggesting that higher aortic stiffness may be particularly important in this regard.
Neuroinflammation and cognitive decline: a TSPO‐PET imaging study.
Authors: Crook Harry , Calsolaro Valeria , Edison Paul 
Published: December 2023

AbstractBackgroundNeuroinflammation is a key driving factor of the pathophysiology of neurodegenerative diseases, including Alzheimer’s disease (AD). Microglia, a major immune cell of the central nervous system, may exert protective effects in the early stages of AD, while may damage the brain milieu in later stages of the disease continuum. The microglial response is mirrored by an increase in the detection of translocator protein (TSPO), a mitochondrial membrane protein that can be targeted with positron emission tomography (PET) imaging. Here, we aim to assess the impact of neuroinflammation on cognition across the AD continuum.Method48 participants (23 patients with AD, 14 patients with mild cognitive impairment (MCI), and 11 cognitively normal controls (CN)) underwent TSPO‐PET (flutriciclamide, [18F]GE180) imaging, magnetic resonance imaging (MRI), and neuropsychological testing. All participants were either high‐ or mixed‐affinity binders for TSPO‐PET tracers, as revealed by TSPO genotyping. The spectral analysis generated a flutriciclamide impulse response function at 90 minutes (IRF90) image, which reflects its volume of distribution. Region of interest and voxel‐wise analyses were conducted to explore the relationship between IRF90 and neuropsychological assessment performance on a group‐level.ResultTSPO‐PET binding was significantly higher in patients with AD compared to CNs across the whole brain, while patients with MCI demonstrated greater TSPO‐PET binding in the hippocampus and medial temporal lobe, compared to CNs. Significant negative associations were observed between neuropsychological assessment scores and IRF90, particularly in the temporal lobe (table 1). At a voxel level, negative correlations were seen between mini‐mental state examination score and IRF90 in temporoparietal regions (figure 1).ConclusionMicroglial response, a marker of neuroinflammation, is elevated in patients with AD and MCI, as measured using TSPO‐PET (flutriciclamide, [18F]GE180) imaging. Heightened neuroinflammation, measured by TSPO‐PET, may exert damaging effects on the brain, as highlighted here by the negative association between TSPO‐PET binding and neuropsychometric assessment performance. This study emphasises the requirement to improve our understanding of the role of neuroinflammation in AD in order to identify pharmacological targets in the future.
Longitudinal biomarkers in Dementia with Lewy bodies: A systematic review and meta‐analysis
Authors: Pozzi Federico Emanuele , van Alphen Juliette Louise , van der Flier Wiesje M. , Lemstra Afina W. 
Published: December 2023

AbstractBackgroundDementia with Lewy bodies (DLB) is the second most common neurodegenerative dementia after Alzheimer’s disease (AD). DLB is a clinically and biologically heterogeneous disease, and little is known about longitudinal trajectories of patients with DLB. Disease progression can be measured with biomarkers capturing structural, functional, and pathological processes, aiding in understanding disease mechanism and discovering potential drug targets. We aimed to perform a systematic review to explore longitudinal patterns of biomarkers in DLB.MethodsSearches were conducted within five different databases, including cohort studies and case series on DLB patients with repeated measures of fluid or imaging biomarkers, and at least six months follow‐up. Fourteen studies were included (Figure 1), reporting data on longitudinal MRI, DaT‐Scan, PiB and flortaucipir‐PET, plasma p‐tau, and HMPAO SPECT, with up to 2,5 years of follow‐up (Table 1). No data on cerebrospinal fluid biomarkers were available. We could only perform a meta‐analysis on annualized brain atrophy rates, with a random effect model and standardized mean differences (SMD).ResultsProgressive putaminal atrophy is seen in DLB patients, even when DaT‐scans are initially normal. In the meta‐analysis, brain atrophy rates were not significantly higher in pure DLB compared to cognitively unimpaired controls, with the exception of accelerated ventricular expansion rates (SMD 0.57 [0.03‐1.10], p = 0.04, 2 studies, 58 patients). Autopsy‐confirmed AD copathology resulted in greater global atrophy rates compared to pure DLB (SMD 0.72 [0.21‐1.31], p = 0.006, Figure 2), similar to AD. AD copathology accelerates temporal lobe and striatal atrophy rates. In one study, brain amyloid accumulation in DLB initially accelerated and then decelerated, similar to AD and cognitively unimpaired subjects, with absolute SUVr lower than AD. In another study, brain tau accumulation rate correlated with brain atrophy rates in the middle temporal pole in DLB patients.ConclusionsOnly a few studies reported longitudinal data on biomarkers in DLB. DLB patients do not have significantly higher brain atrophy rates compared to controls, while the presence of AD copathology accelerates global and regional atrophy. Future studies with longer follow‐ups and multimodal biomarkers are needed to further characterize disease progression and elucidate clinical and biological heterogeneity.