The latest medical research on Dementia
The research magnet gathers the latest research from around the web, based on your specialty area. Below you will find a sample of some of the most recent articles from reputable medical journals about dementia gathered by our medical AI research bot.
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Request AccessCentiloid recommendations for clinical context-of-use from the AMYPAD consortium.
Alzheimers & DementiaAmyloid-PET quantification through the tracer-independent Centiloid (CL) scale has emerged as an essential tool for the accurate measurement of amy...
Unveiling the molecular mechanisms of Danggui-Shaoyao-San against Alzheimer's disease in APP/PS1 mice via integrating proteomic and metabolomic approaches.
Journal Alzheimers Research TherapyAlzheimer's disease (AD) is the most prevalent neurodegenerative disorder for which no effective therapy is currently available. Given that various attempts to target beta-amyloid (Aβ) have been unsuccessful in clinical trials, other potential pathogenic factors such as brain energy metabolism (EM) have attracted increasing attention. Traditional Chinese medicines, including danggui-shaoyao-san (DSS), play a notable role in AD. However, it remains unclear whether DSS exerts therapeutic effects on AD through EM regulation.
In this study, we conducted behavioural tests, Nissl staining, haematoxylin and eosin staining, and thioflavin S staining, in APP/PS1 mice to assess the pharmacodynamic effect of DSS on AD. Subsequently, we integrated the drug target network of herbal ingredients in DSS and evaluated their absorption, distribution, metabolism, excretion, and toxicity properties to identify the core ingredients. We used proteomic and metabolomic approaches to explore the potential mechanisms of action of DSS against AD. Consequently, we verified the mechanism underlying EM using qPCR, western blotting, and ELISA.
In vivo experimental results revealed that DSS ameliorated cognitive impairment in APP/PS1 mice, attenuated neuronal apoptosis, and reduced Aβ burden. Furthermore, the drug-target network comprised 6,514 drug-target interactions involving 1,118 herbal ingredients and 218 AD genes, of which 253 were identified as the core ingredients in DSS. The proteomic results implied that DSS could act on EM to alleviate AD, and targeted energy metabolomics suggested that DSS regulated 47 metabolites associated with EM. Mechanistically, we found that DSS could regulate the GSK3β/PGC1α signalling pathway to improve brain glucose uptake and mitigate mitochondrial dysfunction and oxidative stress, ultimately promoting EM to treat AD.
Our study is the first to integrate multi-omics approaches to reveal that DSS could regulate the GSK3β/PGC1α signalling pathway to exert therapeutic effects in AD through the promotion of EM, thereby providing new insights into the mechanism of action of DSS against AD.
Personal social network strengthens adherence to lifestyle changes in individuals with subjective cognitive decline.
Alzheimers Dementia AmsterdamProviding medical advice regarding lifestyle changes is currently the most effective intervention for delaying dementia onset among individuals with subjective cognitive decline (SCD). Adherence to such advice can be influenced by individual's social environment. We measured that impact within a Latinamerican population.
We recruited 183 SCD individuals from a Memory Clinic, analyzed their health-related, and provided them with medical advice. We assessed personal network composition and its healthy habits. We evaluated adherence to medical advice 6 months later.
The proportion of heavy drinkers in the network is a risk factor to reduce alcohol consumption (odds ratio [OR] = 31.2, 95% confidence interval [CI] [3.73,301], p = 0.002), poor diets in the network hinders improving diet (p < 0.001 OR = 74.1, 95% CI [14.7,471]), and sedentary people in the network make it difficult to start exercising (OR = 4.92 95% CI [1.39,18.8], p = 0.016).
Personal networks have an inertial effect, as relationships engaged in an unhealthy habit lower the probability of individuals to quit that habit.
Association of precuneus Aβ burden with default mode network function.
Alzheimers & DementiaIt remains unclear whether the local amyloid-beta (Aβ) burden in key regions within the default mode network (DMN) affects network and cognitive functions.
Participants included 1002 individuals from the Chinese Preclinical Alzheimer's Disease Study cohort who underwent 18F-florbetapir positron emission tomography resting-state functional magnetic resonance imaging scanning and neuropsychological tests. The correlations between precuneus (PRC) Aβ burden, DMN function, and cognitive function were investigated.
In individuals with high PRC Aβ burden, there is a bidirectional relationship between DMN local function or functional connectivity and PRC Aβ deposition across various cognitive states, which is also linked to cognitive function. Even below the PRC Aβ threshold, DMN function remains related to PRC Aβ deposition and cognitive performance.
Precuneus (PRC) Aβ burden impacts DMN function in different cognitive stages. High PRC Aβ burden is linked to early neural compensation and subsequent dysfunction. Low PRC Aβ burden correlates with neural changes before significant Aβ accumulation. Changes in DMN function and connectivity provide insights into AD progression. Early detection of regional Aβ burden can help monitor the risk of cognitive decline.
Neighborhood physical activity facilities predict risk of incident mixed and vascular dementia: The Cardiovascular Health Cognition Study.
Alzheimers & DementiaNeighborhood environments may promote neurocognitive health in part by providing amenities that encourage physical activity. We examined associations between quantity of walkable facilities, including specifically physical activity facilities (e.g., gyms, recreation centers), with risk of incident dementia.
Participants included 2923 adults ≥ 65 years old from the Cardiovascular Health Cognition Study (1992-1999), with clinically adjudicated dementia classified over a median 6.0 years of follow-up. Walkable facilities were measured within 1 km (Euclidean) of home. Self-reported baseline physical activity was considered a moderator.
In adjusted Cox models, participants with ≥ 2 (vs. 0) physical activity facilities had reduced risk of mixed/vascular dementia, but not Alzheimer's disease, particularly after excluding individuals in the bottom 20th percentile of physical activity (hazard ratio = 0.56, 95% confidence interval: 0.35-0.89).
We examined associations between nearby walkable facilities and incident dementia. Facilities within 1 km were counted via the National Establishment Time Series Database. More physical activity facilities predicted lower risk of mixed/vascular dementia. No associations were found between walkable facilities and incident Alzheimer's disease.
Visual read of [F-18]florquinitau PET that includes and extends beyond the mesial temporal lobe is associated with increased plasma pTau217 and cognitive decline in a cohort that is enriched with risk for Alzheimer's disease.
Alzheimers & DementiaPatterns of signal from tau positron emission tomography (tau-PET) confined to the medial temporal lobe (MTL) or extended into the neocortex may be relevant for Alzheimer's disease (AD) research if they are linked to differential biomarker levels and cognitive decline.
Visual assessment of Tau-PET [F-18]florquinitau (FQT) exams from 728 initially non-demented older adults yielded four uptake groups: tau-negative (T-), MTL-only (T+MTL), neocortex-only (T+Neo), or both (T+MTL&Neo). Mixed effects models assessed group differences in retrospective cognitive and plasma pTau217 trajectories.
T+MTL&Neo was the most common T+ group (n = 97; 93% A+) and exhibited the sharpest worsening in cognitive and pTau217 trajectories before tau PET.
Visual assessments of Tau-PET FQT revealed four distinct uptake groups: tau-negative (T-), MTL-only (T+MTL), neocortex-only (T+Neo), or both (T+MTL&Neo). Amyloid positive participants in the T+MTL and T+MTL&Neo categories showed a retrospectively faster decline in their cognitive trajectories, and a sharper increase in pTau217 levels in plasma, compared to T-. The T+MTL&Neo group displayed sharper trajectories compared with the other Tau positive groups in both their cognitive scores and pTau217 plasma levels. Our results suggest that participants with Tau present in both MTL and neocortex represent an intermediate to advanced stage of AD, whereas participants with signals confined to either MTL or neocortex could represent earlier AD stages.
Conversion to Alzheimer's disease dementia from normal cognition directly or with the intermediate mild cognitive impairment stage.
Alzheimers & DementiaProgression to Alzheimer's disease (AD) dementia from normal cognition (NC) can follow different trajectories, with most progressing through a recognizable mild cognitive impairment stage (NC-MCI-AD), while some individuals transition quickly from NC to AD dementia (NC-AD).
We compared demographic characteristics, health factors, and cognitive and functional assessments across three time points: the first NC visit, the last NC visit, and the first AD dementia visit.
The NC-MCI-AD group showed greater impairment in cognitive and functional scores at AD dementia diagnosis, despite maintaining better cognitive function during the NC stage. Analysis of yearly changes revealed negligible differences during NC. However, the yearly change during the AD dementia stage suggested potentially more rapid functional decline in the NC-AD group.
We investigated the disease progression difference between patients who converted to Alzheimer's disease (AD) dementia from normal cognition (NC) directly or through the mild cognitive impairment (MCI) stage. We found that the NC-MCI-AD group showed greater impairment in cognitive and functional scores at AD dementia diagnosis. We discovered that the NC-AD group had rapid functional decline once patients were confirmed with AD onset.
Plasma p-tau181 and GFAP reflect 7T MR-derived changes in Alzheimer's disease: A longitudinal study of structural and functional MRI and MRS.
Alzheimers & DementiaAssociations between longitudinal changes of plasma biomarkers and cerebral magnetic resonance (MR)-derived measurements in Alzheimer's disease (AD) remain unclear.
In a study population (n = 127) of healthy older adults and patients within the AD continuum, we examined associations between longitudinal plasma amyloid beta 42/40 ratio, tau phosphorylated at threonine 181 (p-tau181), glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and 7T structural and functional MR imaging and spectroscopy using linear mixed models.
Increases in both p-tau181 and GFAP showed the strongest associations to 7T MR-derived measurements, particularly with decreasing parietal cortical thickness, decreasing connectivity of the salience network, and increasing neuroinflammation as determined by MR spectroscopy (MRS) myo-inositol.
This study leverages high-resolution 7T magnetic resonance (MR) imaging and MR spectroscopy (MRS) for Alzheimer's disease (AD) plasma biomarker insights. Tau phosphorylated at threonine 181 (p-tau181) and glial fibrillary acidic protein (GFAP) showed the largest changes over time, particularly in the AD group. p-tau181 and GFAP are robust in reflecting 7T MR-based changes in AD. The strongest associations were for frontal/parietal MR changes and MRS neuroinflammation.
The pathogenicity of PSEN2 variants is tied to Aβ production and homology to PSEN1.
Alzheimers & DementiaThough recognized as a potential cause of autosomal dominant Alzheimer's disease, the pathogenicity of many PSEN2 variants remains uncertain. We compared amyloid beta (Aβ) production across all missense PSEN2 variants in the AlzForum database and, when possible, to corresponding PSEN1 variants.
We expressed 74 PSEN2 variants, 21 of which had known, homologous PSEN1 pathogenic variants with the same amino acid substitution, in HEK293 cells lacking presenilin 1/2. Aβ production was compared to age at symptom onset (AAO) and between PSEN1/2 homologs.
Aβ42/40 and Aβ37/42 ratios correlated with AAO across all PSEN2 variants, strongly driven by the subset of PSEN2 variants with PSEN1 homologs. Aβ production across PSEN1/2 homologs was highly correlated. PSEN2 AAO correlated with AAO in PSEN1 homologs but was an average of 18.3 years later.
There were associations between the patterns of amyloid beta (Aβ) production across presenilin 2 (PSEN2) variants and age at symptom onset (AAO). PSEN2 variants for which there is a known, corresponding variant in presenilin 1 (PSEN1) are more likely to have abnormal Aβ production patterns that strongly correlate with AAO, compared to those that lack a known PSEN1 counterpart ("non-homologous PSEN2 variants"). Most PSEN2 variants lacking PSEN1 counterparts had Aβ42/40 ratios close to those of wild-type PSN2, arguing against their pathogenicity. Homologous PSEN1 and PSEN2 variants had correlated Aβ42/40 and Aβ37/42 ratios, indicating that the corresponding amino acid substitution in each presenilin may have largely similar biochemical effects on γ-secretase processivity.
Marmosets as model systems for the study of Alzheimer's disease and related dementias: Substantiation of physiological tau 3R and 4R isoform expression and phosphorylation.
Alzheimers & DementiaMarmosets spontaneously develop pathological hallmarks of Alzheimer's disease (AD) including amyloid beta plaques. However, tau expression in the marmoset brain has been understudied.
Isoforms of tau were examined by western blot, mass spectrometry, immunofluorescence, and immunohistochemical staining.
3R and 4R tau isoforms are expressed in marmoset brains at both the transcript and protein levels across ages. Mass spectrometry analysis revealed that tau peptides in marmoset corresponded to the 3R and 4R peptides in human brain, with 3R predominating at birth and an ≈40%:60% 3R:4R ratios in adolescents and adults; tau was distributed widely in neurons, with localization in the soma and synaptic regions. Phosphorylation residues were observed on Threonine (Thr) Thr181, Thr217, Thr231, Serine (Ser) Ser202/Thr205, and Ser396/Ser404.
Our results confirm both 3R and 4R tau isoform expression and phosphorylation residues in the marmoset brain, and emphasize the significance of marmosets with natural expression of AD-related hallmarks as important translational models for AD. Highlights We report comprehensive characterization of tau isoform expression in marmoset brains across the lifespan. 3R and 4R tau isoforms are expressed in marmoset brains at both the transcript and protein levels across ages. These data emphasize the significance of marmosets with natural expression of primate-specific traits that are important for the study of Alzheimer's disease.
Long-term effects of collaborative dementia care on quality of life and caregiver well-being.
Alzheimers & DementiaCollaborative dementia care models with care navigation, including the Care Ecosystem, improve outcomes for persons living with dementia (PLWDs) and their caregivers. The effects of continuous care over long periods have not been studied.
In this randomized clinical trial with 456 PLWD-caregiver dyads with high caregiver burden, we evaluated the cumulative 5-year treatment effect on PLWD quality of life, health care utilization, caregiver depression, self-efficacy, and burden.
Five-year participation was associated with higher quality of life, lower caregiver depression, and higher caregiver self-efficacy (all p's < 0.05) with a trend for lower burden (p = 0.07). Treatment effects were most robust during the first 2 years. The effects on emergency department visits and hospitalizations were not significant.
Collaborative dementia care with care navigation was evaluated over 5 years using a randomized clinical trial. The care was associated with better quality of life for the person with dementia and well-being for the caregiver. The most robust treatment effects were in the first 2 years.
Counseling and disclosure practices in predictive Alzheimer's disease diagnostics: A scoping review.
Alzheimers & DementiaNew possibilities of biomarker-based predictive technologies for Alzheimer's disease (AD) have become more reliable as well as more accessible. Sta...
