Global, regional, and national burden of Alzheimer's disease and other dementias, 1990-2016: a systematic analysis for the Global Burden of Disease Study 2016

Study on the effect of 40 Hz non-invasive light therapy system. A protocol for a randomized, double-blinded, placebo-controlled clinical trial

Introduction

With no cure or effective treatment, the prevalence of patients with Alzheimer's disease (AD) is expected to intensify, thereby increasing the social and financial burden on society. Light-based 40 Hz brain stimulation is considered a novel treatment strategy for patients with AD that may alleviate some of this burden. The clinical trial ALZLIGHT will utilize a novel Light Therapy System (LTS). The LTS uses Invisible Spectral Flicker for non-invasive induction of 40 Hz neural activity. This protocol describes a trial evaluating the efficacy and safety of a light-based 40 Hz brain stimulation in patients with mild-to-moderate AD.

Methods

62 patients with mild-to-moderate AD will participate in a randomized, double-blinded, placebo-controlled, parallel-group, and single-center trial. The participants will partake in an enrollment period of 1 month, an intervention period of 6 months, and a 1.5-month post-interventional follow-up period. Prior to the baseline measurement (week 0), the patients will be randomized to either active or placebo intervention from baseline (week 0) to post-intervention follow-up (week 26).

Discussion

This protocol describes a randomized, double-blinded, placebo-controlled clinical trial that may increase the understanding of the effect of gamma oscillations in the human brain and how it could be utilized as a novel and important tool for the treatment of AD. The effect is measured through a large, multidisciplinary assessment battery.Clinical trial registration:www.ClinicalTrials.gov, (NCT05260177). Registered on March 2, 2022.

"Better Living with Non-memory-led Dementia": protocol for a feasibility randomised controlled trial of a web-based caregiver educational programme

BACKGROUND

Non-memory-led dementias such as posterior cortical atrophy (PCA), primary progressive aphasia (PPA) and behavioural variant frontotemporal dementia (bvFTD) are low prevalent and often affect individuals under the age of 65. Tailored educational and support resources for caregivers of people living with these dementia phenotypes are scarce and unevenly distributed geographically. Web-based educational programmes are emerging as promising alternatives to improve caregiver self-efficacy and well-being. Here, we present the protocol of a study aiming to assess the feasibility of a co-produced online educational programme for caregivers of people living PCA, PPA and bvFTD: the Better Living with Non-memory-led Dementia programme.

METHODS

A randomised controlled feasibility trial will be conducted on a sample of 30 caregivers of people living with PCA, PPA and bvFTD. Participants will be recruited among members of the support organisation Rare Dementia Support (based at UCL in the UK). The intervention group will be given access to an 8-week co-produced web-based educational programme consisting of 6 modules addressing education about PCA, PPA and bvFTD and support strategies for the person with dementia and for the caregiver. The control group will receive treatment as usual (TAU). Feasibility will be measured through feasibility of recruitment, clinical measurement tools and acceptability. Clinical measures will be used to assess preliminary efficacy and data on completion rates, missing data and variability used to decide on measures to be included in a full-scale trial. Allocation ratio will be 2:1 (intervention:control) stratified by diagnosis. Feasibility of recruitment and acceptability will be assessed. Clinical measures will be administered at baseline and 8-week and 3-month post-randomisation. The control group will be offered access to the intervention at the completion of data collection. Participants will be unblinded, and all measures will be self-reported online.

DISCUSSION

Online-delivered educational programmes show potential for improving care competency of caregivers and may contribute to overcoming geographical inequalities in local provision of support services. This pilot study will inform a fully powered international trial to determine the effectiveness of Better Living with Non-memory-led Dementia.

TRIAL REGISTRATION

This trial has been registered prospectively on the Clinical Trials Registry on 1st September 2022, registration number NCT05525377.

The amyloid cascade hypothesis: an updated critical review

Results from recent clinical trials of antibodies that target amyloid-β (Aβ) for Alzheimer's disease have created excitement and have been heralded as corroboration of the amyloid cascade hypothesis. However, while Aβ may contribute to disease, genetic, clinical, imaging and biochemical data suggest a more complex aetiology. Here we review the history and weaknesses of the amyloid cascade hypothesis in view of the new evidence obtained from clinical trials of anti-amyloid antibodies. These trials indicate that the treatments have either no or uncertain clinical effect on cognition. Despite the importance of amyloid in the definition of Alzheimer's disease, we argue that the data point to Aβ playing a minor aetiological role. We also discuss data suggesting that the concerted activity of many pathogenic factors contribute to Alzheimer's disease and propose that evolving multi-factor disease models will better underpin the search for more effective strategies to treat the disease.

Elettaria cardamomum (L.) Maton Essential Oil: An Interesting Source of Bioactive Specialized Metabolites as Inhibitors of Acetylcholinesterase and Butyrylcholinesterase

Elettaria cardamomum (L.) Maton (Zingiberaceae family) is a plant traditionally used in Ayurvedic and Chinese medicine. In this work, the essential oil of E. cardamomum was found to inhibit the enzymes AChE (62.6% of inhibition, IC50 24.9 μg/mL) and BChE (55.8% of inhibition, IC50 25.9 μg/mL) by performing an in vitro colorimetric assay using the Ellman method. A bio-guided fractionation approach was used to isolate fractions/pure compounds that were tested individually to evaluate their activity. The resulting oxygenated fraction was found to be active against both AChE (percentage inhibition 42.8%) and BChE (percentage inhibition 63.7%), while the hydrocarbon fraction was inactive. The activity was attributed to a pool of oxygenated terpenes (α-terpinyl acetate, 1,8-cineole, linalool, linalyl acetate, and α-terpineol) that synergistically contributed to the overall activity of the essential oil.

Predicting amyloid PET positivity using plasma p-tau181 and other blood-based biomarkers

Introduction

This study aimed to determine the efficacy of combining plasma phosphorylated tau (p-tau)181, amyloid beta (Aβ)42/Aβ40, neurofilament light (NfL), and apolipoprotein E (APOE) genotypes for detecting positive amyloid positron emission tomography (PET), which is little known in the Asian population, in two independent cohorts.

Methods

Biomarkers were measured using a single-molecule array (Simoa) in a cohort study (Asan). All participants underwent amyloid PET. Significant changes in the area under the curve (AUC) and Akaike Information Criterion values were considered to determine the best model. The generalizability of this model was tested using another cohort (KBASE-V).

Results

In the Asan cohort, after adjusting for age and sex, p-tau181 (AUC = 0.854) or APOE ε4 status (AUC = 0.769) distinguished Aβ status with high accuracy. Combining them or adding NfL and Aβ42/40 improved model fitness. The best-fit model included the plasma p-tau181, APOE ε4, NfL and Aβ42/40. The models established from the Asan cohort were tested in the KBASE-V cohort. Additionally, in the KBASE-V cohort, these three biomarker models had similar AUC in cognitively unimpaired (AUC = 0.768) and mild cognitive impairment (MCI) (AUC = 0.997) participants.

Conclusions

Plasma p-tau181 showed a high performance in determining Aβ-PET positivity. Adding plasma NfL and APOE ε4 status improved the model fit without significant improvement in AUC.

Diagnostic disclosure of Alzheimer's disease in Brazil: a national survey of specialized physicians

BACKGROUND

The diagnosis of Alzheimer's disease (AD) can bring financial and emotional consequences to patients and caregivers. Whether or not the diagnosis should be disclosed to patients is a matter of debate amongst physicians and can be influenced by culture and experience.

OBJECTIVE

To investigate the current practice of physicians who attend and treat patients with dementia in Brazil regarding the disclosure of dementia diagnosis and compare the practice with what has been performed 15 years ago in the country.

METHODS

Data were evaluated using an electronic questionnaire. The questions used to carry out this research were similar to the questions of the study carried out 15 years ago 9. The form was sent to the Brazilian Academy of Neurology, the Brazilian Association of Geriatrics and Gerontology, and the Brazilian Association of Psychiatry, which forwarded it to their members. Analyses were conducted through non-parametric statistical tests, with a post-hoc assessment.

RESULTS

397 physicians responded to the survey, of which 231 are neurologists, 124 geriatricians, 29 psychiatrists and 13 from other specialties. The mean age was 45.2 years. The majority (66.7%) of the physicians reveal the diagnosis of AD always or usually. The youngest group of neurologists were more likely to disclose the diagnosis than the oldest group with a significant difference between them. In comparison to the 2008 Brazilian study, the percentage of physicians who always or usually disclose the diagnosis has risen by 22%. On the other hand, 12.3% of the physicians rarely or never disclose the diagnosis, in comparison to 25,3% in 2008. The main reasons for not disclosing the diagnosis concern the patients' mental health.

CONCLUSION

Advances in dementia knowledge and biomarkers availability probably explain the increase in the rate of disclosure. The main challenge is to reconcile the autonomy of affected individuals, mental health issues after the diagnosis and the family member's opinion.

Effect of Neurotoxin Exposure on Blood Biomarkers of Neurodegeneration and Alzheimer Disease

AIM

To determine whether exposure to neurotoxins in midlife is associated with changes in blood-based biomarkers of neurodegeneration and Alzheimer disease pathology.

METHODS

Blood cadmium, lead, neurofilament light (NfL) chain, total tau (TTau), and amyloid beta (Aβ) 40 and Aβ42 concentrations were measured in 1516 participants in the Beaver Dam Offspring Study. Linear mixed-effect models were used to determine associations between baseline cadmium and lead levels and baseline NfL, TTau, and Aβ42/Aβ40, and 10-year change in concentrations using repeated measures of these biomarkers as the outcome.

RESULTS

In women, higher cadmium and lead levels were associated with higher baseline TTau concentrations. A higher baseline cadmium level was associated with lower baseline Aβ42/Aβ40 in both men and women. In age-sex-adjusted models, a doubling in baseline cadmium level was associated with a 0.2% (95% CI: 0.0, 0.3) higher increase per year in NfL concentrations. In men, a doubling of baseline lead level was associated with a 0.9% (95% CI: 0.1, 1.7) higher increase per year in TTau concentration.

CONCLUSIONS

Participants with relatively higher levels of cadmium and lead had blood biomarker concentrations consistent with more neuronal damage and Alzheimer disease pathology. Environmental exposure to neurotoxins may contribute to neurodegeneration.

AI-based assessments of speech and language impairments in dementia

Recent advancements in the artificial intelligence (AI) domain have revolutionized the early detection of cognitive impairments associated with dementia. This has motivated clinicians to use AI-powered dementia detection systems, particularly systems developed based on individuals' and patients' speech and language, for a quick and accurate identification of patients with dementia. This paper reviews articles about developing assessment tools using machine learning and deep learning algorithms trained by vocal and textual datasets.

A trichotomy method for defining homogeneous subgroups in a dementia population

INTRODUCTION

Diagnosis of dementia in the aging brain is confounded by the presence of multiple pathologies. Mixed dementia (MX), a combination of Alzheimer's disease (AD) proteins with vascular disease (VD), is frequently found at autopsy, and has been difficult to diagnose during life. This report develops a method for separating the MX group and defining preclinical AD (presence of AD factors with normal cognition) and preclinical VD subgroups (presence of white matter damage with normal cognition).

METHODS

Clustering was based on three diagnostic axes: (1) AD factor (ADF) derived from cerebrospinal fluid proteins (Aβ42 and pTau), (2) VD factor (VDF) calculated from mean free water and peak width of skeletonized mean diffusivity in the white matter, and (3) Cognition (Cog) based on memory and executive function. The trichotomy method was applied to an Alzheimer's Disease Neuroimaging Initiative cohort (N = 538).

RESULTS

Eight biologically defined subgroups were identified which included the MX group with both high ADF and VDF (9.3%) and a preclinical VD group (3.9%), and a preclinical AD group (13.6%). Cog is significantly associated with both ADF and VDF, and the partial-correlation remains significant even when the effect of the other variable is removed (r(Cog, ADF/VDF removed) = 0.46, p < 10-28 and r(Cog, VDF/ADF removed) = 0.24, p < 10-7 ).

DISCUSSION

The trichotomy method creates eight biologically characterized patient groups, which includes MX, preclinical AD, and preclinical VD subgroups. Further longitudinal studies are needed to determine the utility of the 3-way clustering method with multimodal biological biomarkers.

Prevalence of Alzheimer's disease dementia in the 50 US states and 3142 counties: A population estimate using the 2020 bridged-race postcensal from the National Center for Health Statistics

INTRODUCTION

This study estimates the prevalence and number of people living with Alzheimer's disease (AD) dementia in 50 US states and 3142 counties.

METHODS

We used cognitive data from the Chicago Health and Aging Project, a population-based study, and combined it with the National Center for Health Statistics 2020 bridged-race population estimates to determine the prevalence of AD in adults ≥65 years.

RESULTS

A higher prevalence of AD was estimated in the east and southeastern regions of the United States, with the highest in Maryland (12.9%), New York (12.7%), and Mississippi (12.5%). US states with the highest number of people with AD were California, Florida, and Texas. Among larger counties, those with the highest prevalence of AD were Miami-Dade County in Florida, Baltimore city in Maryland, and Bronx County in New York.

DISCUSSION

The state- and county-specific estimates could help public health officials develop region-specific strategies for caring for people with AD.

Prevalence of dementia among older age people and variation across different sociodemographic characteristics: a cross-sectional study in Bangladesh

Background

Dementia is a significant global health issue, particularly for low-income and middle-income countries which majorly contribute to the dementia cases reported globally (67%). We estimated the prevalence of dementia among older people in Bangladesh and compared the estimate across different sociodemographic characteristics and divisions.

Methods

A cross-sectional study was conducted in 2019 among individuals aged 60 years or older in seven administrative divisions in Bangladesh. Equal numbers of male and female participants were recruited from each division through a multi-stage random sampling technique. Recruitment was proportionally distributed in urban and rural areas in each division. Following consent, the Mini Mental State Examination (MMSE) was performed on all participants. Dementia was defined as an MMSE score of <24 out of 30. Data on age, sex, education, marital status, occupation, socioeconomic status, and type of community (urban or rural) were obtained using a structured questionnaire to compare the prevalence of dementia across different sociodemographic characteristics.

Findings

Between January and December 2019, 2795 individuals were recruited including ∼400 from each of the seven administrative divisions. The mean age was 67 years (SD: 7), 68% were from rural areas and 51% were female. The prevalence of dementia was 8.0% (95% CI: 7.0-8.9%) with variations across age, sex, education, marital status, occupation, and division. No variations in prevalence were observed across urban/rural locations or socioeconomic status. After adjusting for age, sex, education, occupation and marital status, the odds of dementia was two times higher in females than males (OR: 2.15, 95% CI: 1.43-3.28); nine times higher in people aged ≥90 years than people aged 60-69 years (OR: 9.62, 95% CI: 4.79-19.13), and three times higher in people with no education compared to those who had completed primary school (OR: 3.10, 95% CI: 1.95-5.17).

Interpretations

The prevalence of dementia is high in Bangladesh and varies across sociodemographic characteristics with a higher prevalence among females, older people, and people with no education. There is an urgent need to identify the key risk factors for dementia in developing countries, such as Bangladesh, to inform the development of context-relevant risk reduction and prevention strategies.

Funding

None.

Association of NOTCH4 and ACHE gene polymorphism in Alzheimer's disease of Gujarat cohort

BACKGROUND

Alzheimer's Disease (AD) is the most common form of dementia, affecting cognitive and behavioral functions. AD is a complex disease resulting from the modest effect of gene interaction and environmental factors, as a result of which the exact pathogenesis is still unknown.

AIM

The aim of the present study was to investigate the association between variants of 98 targeted genes with Alzheimer's disease phenotype.

METHOD

A total of 98 genes from 32 AD cases and 11 controls were genotyped using the Haloplex target enrichment method and the PCR-RFLP approach.Association analysis was performed using the PLINK tool to identify the variant significantly associated with AD. Functional enrichment analysis and network analysis was performed using ClueGo and String database respectively. The Expression Quantitative Trait Loci (eQTL) analysis using the Genotype Tissue Expression (GTEx) dataset to explore the possible implication of the variant on the expression of one or more genes in different brain regions and whole blood.

RESULT

Association analysis showed significant association of 19 variant assigned to 16 genes with Alzheimer's with p-value < 0.05 with rs367398/NOTCH4 only variant that passed multiple test corrections. Functional enrichment analysis showed association of these genes with AD. ClueGo and network analysis utilizing the String database suggested that genes are directly and indirectly linked to the AD pathogenesis. eQTL analysis revealed that the rs367398/NOTCH4 and rs1799806/ACHE variant showed significant eQTL for the neighbouring genes.

CONCLUSION

The present study showed the possible role of 16 genes in AD pathogenesis, especially highlighting the role of rs367398/NOTCH4 and rs1799806/ACHE. However further investigation with large cohort is required to study and validate the implication of these variants in the AD pathogenesis.

Dementia death rates prediction

BACKGROUND

Prevalence of dementia illness, causing certain morbidity and mortality globally, places burden on global public health. This study primary goal was to assess future risks of dying from severe dementia, given specific return period, within selected group of regions or nations.

METHODS

Traditional statistical approaches do not have benefits of effectively handling large regional dimensionality, along with nonlinear cross-correlations between various regional observations. In order to produce reliable long-term projections of excessive dementia death rate risks, this study advocates novel bio-system reliability technique, that being particularly suited for multi-regional environmental, biological, and health systems.

DATA

Raw clinical data has been used as an input to the suggested population-based, bio-statistical technique using data from medical surveys and several centers.

RESULTS

Novel spatiotemporal health system reliability methodology has been developed and applied to dementia death rates raw clinical data. Suggested methodology shown to be capable of dealing efficiently with spatiotemporal clinical observations of multi-regional nature. Accurate disease risks multi-regional spatiotemporal prediction being done, relevant confidence intervals have been presented as well.

CONCLUSIONS

Based on available clinical survey dataset, the proposed approach may be applied in a variety of clinical public health applications. Confidence bands, given for predicted dementia-associated death rate levels with return periods of interest, have been reasonably narrow, indicating practical values of advocated prognostics.

Study protocol for development and validation of a single tool to assess risks of stroke, diabetes mellitus, myocardial infarction and dementia: DemNCD-Risk

INTRODUCTION

Current efforts to reduce dementia focus on prevention and risk reduction by targeting modifiable risk factors. As dementia and cardiometabolic non-communicable diseases (NCDs) share risk factors, a single risk-estimating tool for dementia and multiple NCDs could be cost-effective and facilitate concurrent assessments as compared with a conventional single approach. The aim of this study is to develop and validate a new risk tool that estimates an individual's risk of developing dementia and other NCDs including diabetes mellitus, stroke and myocardial infarction. Once validated, it could be used by the public and general practitioners.

METHODS AND ANALYSIS

Ten high-quality cohort studies from multiple countries were identified, which met eligibility criteria, including large representative samples, long-term follow-up, data on clinical diagnoses of dementia and NCDs, recognised modifiable risk factors for the four NCDs and mortality data. Pooled harmonised data from the cohorts will be used, with 65% randomly allocated for development of the predictive model and 35% for testing. Predictors include sociodemographic characteristics, general health risk factors and lifestyle/behavioural risk factors. A subdistribution hazard model will assess the risk factors' contribution to the outcome, adjusting for competing mortality risks. Point-based scoring algorithms will be built using predictor weights, internally validated and the discriminative ability and calibration of the model will be assessed for the outcomes. Sensitivity analyses will include recalculating risk scores using logistic regression.

ETHICS AND DISSEMINATION

Ethics approval is provided by the University of New South Wales Human Research Ethics Committee (UNSW HREC; protocol numbers HC200515, HC3413). All data are deidentified and securely stored on servers at Neuroscience Research Australia. Study findings will be presented at conferences and published in peer-reviewed journals. The tool will be accessible as a public health resource. Knowledge translation and implementation work will explore strategies to apply the tool in clinical practice.

Leisure-Time Television Viewing and Computer Use, Family History, and Incidence of Dementia

INTRODUCTION

Time spent on screen-based sedentary activities is significantly associated with dementia risk, however, whether the associations vary by family history (FHx) of dementia is currently unknown. We aimed to examine independent associations of two prevalent types of screen-based sedentary activities (television [TV] viewing and computer use) with dementia and assess the modifying effect of FHx.

METHODS

We included 415,048 individuals free of dementia from the UK Biobank. Associations of TV viewing, computer use, and FHx with dementia risk were determined using Cox regression models. We estimated both multiplicative- and additive-scale interactions between TV viewing and computer use and FHx.

RESULTS

During a median follow-up of 12.6 years, 5,549 participants developed dementia. After adjusting for potential confounding factors, we observed that moderate (2-3 h/day; hazard ratio [HR] 1.13, 95% confidence interval 0.03-1.23) and high (>3 h/day; 1.33, 1.21-1.46) TV viewing was associated with a higher dementia risk, compared with low (0-1 h/day) TV viewing. Using restricted cubic spline models, the relationship of TV viewing with dementia was nonlinear (relative to 0 h/day; p for nonlinear = 0.005). We found that >3 h/day of TV viewing was associated with a 42% (1.42, 1.18-1.71) higher dementia risk in participants with FHx while a 30% (1.30, 1.17-1.45) in those without FHx. For computer use, both low (0 h/day; 1.41, 1.33-1.50) and high (>2 h/day; 1.17, 1.05-1.29) computer use were associated with elevated dementia risk, compared with moderate (1-2 h/day) computer use. We observed a J-shaped relationship with dementia (relative to 2 h/day; p for nonlinear <0.001). Compared with 1-2 h/day of computer use, the HRs of dementia were 1.46 (1.29-1.65) and 1.10 (0.90-1.36) for 0 h/day and >2 h/day of computer use in participants with FHx, respectively, while the corresponding HRs were 1.40 (1.30-1.50) and 1.19 (1.06-1.33) in those without FHx. We observed a positive additive interaction (RERI 0.29, 0.06-0.53) between computer use and FHx, while little evidence of interaction between TV viewing and FHx.

CONCLUSIONS

The time spent on TV viewing and computer use were independent risk factors for dementia, and the adverse effects of computer use and FHx were additive. Our findings point to new behavioral targets for intervention on preventing an early onset of dementia, especially for those with FHx.

Age at Onset of Heart Failure and Subsequent Risk of Dementia: A Longitudinal Cohort Study

BACKGROUND

The average age at onset of heart failure (HF) shows a progressive decrease in recent years; however, the association between age at onset of HF and risk of subsequent dementia remains undetermined.

OBJECTIVES

The study sought to examine whether younger onset age of HF is associated with a higher risk of incident dementia.

METHODS

Individual-level data from the UK Biobank cohort study were analyzed in the present study. Cox regression models and the propensity score matching method were used to analyze the associations of HF and its onset age with subsequent all-cause dementia, Alzheimer's disease (AD), and vascular dementia (VD).

RESULTS

Compared with 442,791 participants without HF, those with HF had a higher risk of all-cause dementia (HR: 1.14). Among 14,413 participants with HF, multivariable-adjusted HRs for all-cause dementia, AD, and VD were 1.18, 1.64, and 1.27, respectively, per 10-year decrease in age at HF onset. The propensity score matching analyses found that the strength of association between HF and all-cause dementia increased with decreasing onset age of HF (≥75 years, HR: 1.05; 65-74 years, HR: 1.10; <65 years, HR: 1.67) after multivariable adjustment. Similarly, participants with onset age of HF <65 years had the greatest HRs for incident AD and VD, compared with their matched control subjects.

CONCLUSIONS

Younger age at HF onset was associated with increased risk of dementia. Individuals with an onset age of HF before 65 years of age may represent a particularly vulnerable population for dementia irrespective of subtypes and need careful monitoring and timely intervention to attenuate subsequent risk of incident dementia.

Leucocyte telomere length, brain volume and risk of dementia: a prospective cohort study

Background

The evidence regarding the association between leucocyte telomere length (LTL) and brain health is sparse and inconclusive.

Aims

To investigate the associations of LTL with brain structure and the risk of dementia based on a large-scale prospective study.

Methods

LTL in the peripheral blood was measured by the quantitative polymerase chain reaction (qPCR) assay from 439 961 individuals in the UK Biobank recruited between 2006 and 2010 and followed up until 2020. Electronic health records were used to record the incidence of dementia, including Alzheimer's disease (AD) and vascular dementia (VD). The brain structure, including total and regional brain volume, of 38 740 participants was then assessed by magnetic resonance imaging (MRI).

Results

During a median follow-up of 11.6 years, a total of 5 820 (1.3%) dementia cases were documented. The restricted cubic spline model showed significant overall associations between LTL and the risk of dementia and AD (p for overall <0.05). The multivariable adjusted hazard ratios (HRs) for the lowest LTL tertile compared with the highest LTL tertile were 1.14 (95% confidence interval (CI): 1.06 to 1.21) for dementia, 1.28 (95% CI: 1.12 to 1.46) for AD and 1.18 (95% CI: 0.98 to 1.42) for VD. Furthermore, we found that shorter LTL was associated with smaller total brain volume (β=-0.012 8, p=0.003), white matter volume (β=-0.022 4, p<0.001), hippocampus volume (β=-0.017 2, p<0.001), thalamus volume (β=-0.023 9, p<0.001) and accumbens (β=-0.015 5, p=0.001).

Conclusions

Shorter LTL is associated with total and regional brain structure and a higher risk of incident dementia and AD, implying the potential of telomere length as a predictive biomarker of brain health.

Gene expression analysis reveals GRIN1, SYT1, and SYN2 as significant therapeutic targets and drug repurposing reveals lorazepam and lorediplon as potent inhibitors to manage Alzheimer's disease

Alzheimer's disease (AD) is a slowly progressive neurodegenerative disease and a leading cause of dementia. We aim to identify key genes for the development of therapeutic targets and biomarkers for potential treatments for AD. Meta-analysis was performed on six microarray datasets and identified the differentially expressed genes between healthy and Alzheimer's disease samples. Thereafter, we filtered out the common genes which were present in at least four microarray datasets for downstream analysis. We have constructed a gene-gene network for the common genes and identified six hub genes. Furthermore, we investigated the regulatory mechanisms of these hub genes by analysing their interaction with miRNAs and transcription factors. The gene ontology analysis results highlighted the enriched terms significantly associated with hub genes. Through an extensive literature survey, we found that three of the hub genes including GRIN1, SYN2, and SYT1 were critically involved in disease development. To leverage existing drugs for potential repurposing, we predicted drug-gene interaction using the drug-gene interaction database, and performed molecular docking studies. The docking results revealed that the drug compounds had strong interactions and favorable binding with selected hub genes. Lorazepam exhibits a binding energy of -7.3 kcal/mol with GRIN1, Lorediplon exhibits binding energies of -7.7 kcal/mol and -6.3 kcal/mol with the SYT1, and SYN2 respectively. In addition, 100 ns molecular dynamics simulations were carried out for the top complexes and apo protein as well. Furthermore, the MM-PBSA free energy calculations also revealed that these complexes are stable and had favorable energies. According to our study, the identified hub gene could serve as a biomarker as well as a therapeutic target for AD, and the proposed repurposed drug molecules appear to have promising efficacy in treating the disease.Communicated by Ramaswamy H. Sarma.

The epidemiology of mild cognitive impairment, Alzheimer's disease and related dementia in U.S. veterans

INTRODUCTION

US veterans have a unique dementia risk profile that may be evolving over time.

METHODS

Age-standardized incidence and prevalence of Alzheimer's disease (AD), AD and related dementias (ADRD), and mild cognitive impairment (MCI) was estimated from electronic health records (EHR) data for all veterans aged 50 years and older receiving Veterans Health Administration (VHA) care from 2000 to 2019.

RESULTS

The annual prevalence and incidence of AD declined, as did ADRD incidence. ADRD prevalence increased from 1.07% in 2000 to 1.50% in 2019, primarily due to an increase in the prevalence of dementia not otherwise specified. The prevalence and incidence of MCI increased sharply, especially after 2010. The prevalence and incidence of AD, ADRD, and MCI were highest in the oldest veterans, in female veterans, and in African American and Hispanic veterans.

DISCUSSION

We observed 20-year trends of declining prevalence and incidence of AD, increasing prevalence of ADRD, and sharply increasing prevalence and incidence of MCI.

Gender-based research underscores sex differences in biological processes, clinical disorders and pharmacological interventions

Earlier research has presumed that the male and female biology is similar in most organs except the reproductive system, leading to major misconceptions in research interpretations and clinical implications, with serious disorders being overlooked or misdiagnosed. Careful research has now identified sex differences in the cardiovascular, renal, endocrine, gastrointestinal, immune, nervous, and musculoskeletal systems. Also, several cardiovascular, immunological, and neurological disorders have shown differences in prevalence and severity between males and females. Genetic variations in the sex chromosomes have been implicated in several disorders at young age and before puberty. The levels of the gonadal hormones estrogen, progesterone and testosterone and their receptors play a role in the sex differences between adult males and premenopausal women. Hormonal deficiencies and cell senescence have been implicated in differences between postmenopausal and premenopausal women. Specifically, cardiovascular disorders are more common in adult men vs premenopausal women, but the trend is reversed with age with the incidence being greater in postmenopausal women than age-matched men. Gender-specific disorders in females such as polycystic ovary syndrome, hypertension-in-pregnancy and gestational diabetes have attained further research recognition. Other gender-related research areas include menopausal hormone therapy, the "Estrogen Paradox" in pulmonary arterial hypertension being more predominant but less severe in young females, and how testosterone may cause deleterious effects in the kidney while having vasodilator effects in the coronary circulation. This has prompted the National Institutes of Health (NIH) initiative to consider sex as a biological variable in research. The NIH and other funding agencies have provided resources to establish state-of-the-art centers for women health and sex differences in biology and disease in several academic institutions. Scientific societies and journals have taken similar steps to organize specialized conferences and publish special issues on gender-based research. These combined efforts should promote research to enhance our understanding of the sex differences in biological systems beyond just the reproductive system, and provide better guidance and pharmacological tools for the management of various clinical disorders in a gender-specific manner.

The hidden players: Shedding light on the significance of post-translational modifications and miRNAs in Alzheimer's disease development

Alzheimer's disease (AD) is the most prevalent, expensive, lethal, and burdening neurodegenerative disease of this century. The initial stages of this disease are characterized by a reduced ability to encode and store new memories. Subsequent cognitive and behavioral deterioration occurs during the later stages. Abnormal cleavage of amyloid precursor protein (APP) resulting in amyloid-beta (Aβ) accumulation along with hyperphosphorylation of tau protein are the two characteristic hallmarks of AD. Recently, several post-translational modifications (PTMs) have been identified on both Aβ as well as tau proteins. However, a complete understanding of how different PTMs influence the structure and function of proteins in both healthy and diseased conditions is still lacking. It has been speculated that these PTMs might play vital roles in the progression of AD. In addition, several short non-coding microRNA (miRNA) sequences have been found to be deregulated in the peripheral blood of Alzheimer patients. The miRNAs are single-stranded RNAs that control gene expression by causing mRNA degradation, deadenylation, or translational repression and have been implicated in the regulation of several neuronal and glial activities. The lack of comprehensive understanding regarding disease mechanisms, biomarkers, and therapeutic targets greatly hampers the development of effective strategies for early diagnosis and the identification of viable therapeutic targets. Moreover, existing treatment options for managing the disease have proven to be ineffective and provide only temporary relief. Therefore, understanding the role of miRNAs and PTMs in AD can provide valuable insights into disease mechanisms, aid in the identification of biomarkers, facilitate the discovery of novel therapeutic targets, and inspire innovative treatments for this challenging condition.

Association of regular use of ibuprofen and paracetamol, genetic susceptibility, and new-onset dementia in the older population

OBJECTIVE

Although the possible efficacy and adverse effects of paracetamol and ibuprofen on dementia are of global clinical and public health importance, to date, the relationship of the use of paracetamol and ibuprofen with incident dementia remains uncertain. We aimed to assess the prospective association of regular use of ibuprofen and paracetamol with new-onset dementia in an older population.

METHODS

This study included 212,968 participants from the UK Biobank, aged ≥60 years, with available data of ibuprofen, paracetamol use and without dementia at baseline. The primary outcome was new-onset all-cause dementia. The secondary outcomes included new-onset Alzheimer's disease and new-onset vascular dementia.

RESULTS

During a median follow-up of 12.3 years, 6407 (3.0%) participants developed new-onset all-cause dementia. Participants who regularly used paracetamol had a significantly higher risk of new-onset all-cause dementia (adjusted HR, 1.18; 95%CI: 1.10-1.26), compared with non-users. However, there was no significant association between regular use of ibuprofen and new-onset all-cause dementia (users vs. non-users; adjusted HR, 1.06; 95%CI: 0.97-1.16). Furthermore, APOE ε4 dosage and genetic risk scores (GRS) of Alzheimer's disease calculated by 25 single nucleotide polymorphisms did not significantly modify the relationship of regular use of paracetamol and ibuprofen with new-onset all-cause dementia (Both P-interactions >0.05). Similar results were found in the propensity score analysis. Similar findings were also observed for new-onset Alzheimer's disease and new-onset vascular dementia.

CONCLUSIONS

Regular use of paracetamol, but not ibuprofen, was associated with a significantly higher risk of new-onset dementia in the old population, regardless of genetic risks of dementia.

Targeting the central nervous system: From synthetic nanoparticles to extracellular vesicles-Focus on Alzheimer's and Parkinson's disease

Neurodegenerative diseases (NDs) such as Alzheimer's disease (AD) and Parkinson's disease (PD) are an accelerating global health problem as life expectancy rises worldwide. Despite their significant burden in public health systems to date, the existing treatments only manage the symptoms without slowing down disease progression. Thus, the ongoing neurodegenerative process remains untreated. Moreover, the stronghold of the brain-the blood-brain barrier (BBB)-prevents drug penetrance and dwindles effective treatments. In the last years, nanotechnology-based drug delivery systems (DDS) have become a promising approach to target and treat these disorders related to the central nervous system (CNS). PLGA based nanoparticles (NPs) were the first employed DDS for effective drug delivery. However, the poor drug loading capacity and localized immunogenicity prompted the scientific community to move to another DDS such as lipid-based NPs. Despite the lipid NPs' safety and effectiveness, their off-target accumulation together with the denominated CARPA (complement activation-related pseudo allergy) reaction has limited their complete clinical translation. Recently, biological NPs naturally secreted by cells, termed as extracellular vesicles (EVs) have emerged as promising more complex biocompatible DDS. In addition, EVs act as dual players in NDs treatment, as a "cell free" therapy themselves, as well as new biological NPs with numerous characteristics that qualify them as promising carriers over synthetic DDS. The present review aims to display advantages, drawbacks, current limitations and future prospective of the previously cited synthetic and biological DDS to enter the brain and treat one of 21st century most challenging diseases, NDs. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Neurological Disease.

Age-related pathophysiological alterations in molecular stress markers and key modulators of hypoxia

Alzheimer's disease (AD) is characterized by an adverse cellular environment and pathological alterations in distinct brain regions. The development is triggered or facilitated by a condition such as hypoxia or ischemia, or inflammation and is associated with disruptions of fundamental cellular functions, including metabolic and ion homeostasis. Increasing evidence suggests that hypoxia may affect many pathological aspects of AD, including oxidative stress, mitochondrial dysfunction, ER stress, amyloidogenic processing of APP, and Aβ accumulation, which may collectively result in neurodegeneration. Further investigation into the relationship between hypoxia and AD may provide an avenue for the effective preservation and pharmacological treatment of this neurodegenerative disease. This review summarizes the effects of normoxia and hypoxia on AD pathogenesis and discusses the underlying mechanisms. Regulation of HIF-1α and the role of its key players, including P53, VEGF, and GLUT1, are also discussed.

Long-Term Opioid Use and Dementia Risk in Patients With Chronic Pain

OBJECTIVE

This study aimed to investigate the association between long-term opioid use and the risk of dementia in patients with chronic pain.

DESIGN

A head-to-head propensity score-matched (PSM) comparative cohort study was conducted to examine the effect of long-term opioid use on dementia risk. A time-varying Cox regression analysis was performed to calculate adjusted hazard ratios (aHRs) with 95% CIs to identify independent predictors of dementia risk.

SETTING AND PARTICIPANTS

The study included 41,636 patients after PSM, with 20,968 in the opioid use group (≥180 defined daily doses per year) and 20,968 in the non-opioid use group.

METHODS

Multivariate Cox regression analysis was conducted to compare the dementia risk between the opioid use and non-opioid use groups. The incidence of dementia was calculated as the number of cases per 10,000 person-years for each group. Adjusted incidence ratios were determined to assess the dementia risk associated with opioid use.

RESULTS

The multivariate Cox regression analysis showed that the aHR for dementia risk in the opioid use group, compared with the non-opioid use group, was 1.86 (95% CI 1.25-2.09; P < .001). The incidence of dementia was higher among opioid users (44.09 per 10,000 person-years) compared with nonusers (38.85 per 10,000 person-years). The adjusted incidence ratio for dementia risk in the opioid use group, compared with the nonuse group, was 1.13 (95% CI: 1.07-1.21, P < .001).

CONCLUSIONS AND IMPLICATIONS

Long-term opioid use may be associated with an increased risk of dementia in patients with chronic pain. These findings highlight the need for cautious prescribing and monitoring of opioid use in this population, considering the potential long-term cognitive implications.

Genome-Wide Meta-Analysis of Cerebrospinal Fluid Biomarkers in Alzheimer's Disease and Parkinson's Disease Cohorts

BACKGROUND

Amyloid-β, phosphorylated tau (p-tau), and total tau (t-tau) in cerebrospinal fluid are established biomarkers for Alzheimer's disease (AD). In other neurodegenerative diseases, such as Parkinson's disease (PD), these biomarkers have also been found to be altered, and the molecular mechanisms responsible for these alterations are still under investigation. Moreover, the interplay between these mechanisms and the diverse underlying disease states remains to be elucidated.

OBJECTIVE

To investigate genetic contributions to the AD biomarkers and assess the commonality and heterogeneity of the associations per underlying disease status.

METHODS

We conducted genome-wide association studies (GWASs) for the AD biomarkers on subjects from the Parkinson's Progression Markers Initiative, the Fox Investigation for New Discovery of Biomarkers, and the Alzheimer's Disease Neuroimaging Initiative, and meta-analyzed with the largest AD GWAS. We tested heterogeneity of associations of interest between different disease statuses (AD, PD, and control).

RESULTS

We observed three GWAS signals: the APOE locus for amyloid-β, the 3q28 locus between GEMC1 and OSTN for p-tau and t-tau, and the 7p22 locus (top hit: rs60871478, an intronic variant for DNAAF5, also known as HEATR2) for p-tau. The 7p22 locus is novel and colocalized with the brain DNAAF5 expression. Although no heterogeneity from underlying disease status was observed for the earlier GWAS signals, some disease risk loci suggested disease-specific associations with these biomarkers.

CONCLUSIONS

Our study identified a novel association at the intronic region of DNAAF5 associated with increased levels of p-tau across all diseases. We also observed some disease-specific genetic associations with these biomarkers. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

Machine-learning-derived heart and brain age are independently associated with cognition

BACKGROUND AND PURPOSE

A heart age biomarker has been developed using deep neural networks applied to electrocardiograms. Whether this biomarker is associated with cognitive function was investigated.

METHODS

Using 12-lead electrocardiograms, heart age was estimated for a population-based sample (N = 7779, age 40-85 years, 45.3% men). Associations between heart delta age (HDA) and cognitive test scores were studied adjusted for cardiovascular risk factors. In addition, the relationship between HDA, brain delta age (BDA) and cognitive test scores was investigated in mediation analysis.

RESULTS

Significant associations between HDA and the Word test, Digit Symbol Coding Test and tapping test scores were found. HDA was correlated with BDA (Pearson's r = 0.12, p = 0.0001). Moreover, 13% (95% confidence interval 3-36) of the HDA effect on the tapping test score was mediated through BDA.

DISCUSSION

Heart delta age, representing the cumulative effects of life-long exposures, was associated with brain age. HDA was associated with cognitive function that was minimally explained through BDA.

Factors associated with healthy aging in Latin American populations

Latin American populations may present patterns of sociodemographic, ethnic and cultural diversity that can defy current universal models of healthy aging. The potential combination of risk factors that influence aging across populations in Latin American and Caribbean (LAC) countries is unknown. Compared to other regions where classical factors such as age and sex drive healthy aging, higher disparity-related factors and between-country variability could influence healthy aging in LAC countries. We investigated the combined impact of social determinants of health (SDH), lifestyle factors, cardiometabolic factors, mental health symptoms and demographics (age, sex) on healthy aging (cognition and functional ability) across LAC countries with different levels of socioeconomic development using cross-sectional and longitudinal machine learning models (n = 44,394 participants). Risk factors associated with social and health disparities, including SDH (β > 0.3), mental health (β > 0.6) and cardiometabolic risks (β > 0.22), significantly influenced healthy aging more than age and sex (with null or smaller effects: β < 0.2). These heterogeneous patterns were more pronounced in low-income to middle-income LAC countries compared to high-income LAC countries (cross-sectional comparisons), and in an upper-income to middle-income LAC country, Costa Rica, compared to China, a non-upper-income to middle-income LAC country (longitudinal comparisons). These inequity-associated and region-specific patterns inform national risk assessments of healthy aging in LAC countries and regionally tailored public health interventions.

Temporal patterns of the burden of Alzheimer's disease and their association with Sociodemographic Index in countries with varying rates of aging 1990-2019

Objective

To we examine the temporal patterns of the burden of Alzheimer's disease and their association with Sociodemographic Index in countries with varying rates of aging.

Method

Data were obtained from Global Burden of Diseases studies (GBD) 2019 and were used to compare countries with different rates of change in aging population from 1990 to 2019. We collected the data of the age-standardized rates per 100,000 of disability-adjusted life years (DALYs), incidence, prevalence of Alzheimer's disease and other dementias, and the age-specific population rates per 100,000.

Results

Countries with high rates of change in their aging populations had an increase in DALYs, incidence, and prevalence of Alzheimer's disease and other dementias over the last 30 years. Countries with a high rate of change in aging population had a significantly positive association among DALYs, incidence, and prevalence of Alzheimer's disease and other dementias. In contrast, countries with a medium and low rate of change in aging population had negative associations between DALYs and incidence of Alzheimer's disease and other dementias.

Conclusion

This study highlights the significant impact of demographic changes on the burden, prevalence, and incidence of Alzheimer's disease and other dementia. The study also found that robust health care and social systems, as reflected by a higher Sociodemographic Index, can contribute to reducing the burden of Alzheimer's disease and other dementias in medium to low rates of aging populations. The findings underscore the importance of investing in health care and social systems to address the growing burden of these conditions, especially in countries with a high rate of change in the aging population.

Overall and cause-specific mortality in patients with dementia: a population-based cohort study in Taiwan

OBJECTIVES

Information regarding the underlying causes of death (UCODs) and standardized mortality ratio (SMR) of dementia is instrumental in formulating medical strategies to prolong life in persons with dementia (PWD). We examined the leading UCODs among PWD and estimated the overall and cause-specific SMRs in relation to dementia in Taiwan.

METHODS

Data were retrieved from 2 national datasets: the Taiwan Death Registry and the medical claim datasets of the National Health Insurance program. The observed person-years for each study participant were counted from the date of cohort enrollment to either the date of death or the final day of 2016. Sex-specific and age-specific SMRs were then calculated.

RESULTS

The leading UCOD was circulatory disease, accounting for 26.0% of total deaths (n=3,505), followed by respiratory disease at 21.3% (n=2,875). PWD were at significantly increased risk of all-cause mortality (SMR, 2.01), with SMR decreasing with advancing age. A cause-specific analysis revealed that the highest SMRs were associated with nervous system diseases (SMR, 7.58) and mental, behavioral, and neurodevelopmental disorders (SMR, 4.80). Age appeared to modify SMR, suggesting that younger age at cohort enrollment was linked to higher SMRs for nearly all causes of mortality.

CONCLUSIONS

Circulatory and respiratory diseases were the leading UCODs among PWD. The particularly elevated mortality due to nervous system diseases and mental disorders suggests that allocating more resources to neurological and psychiatric services is warranted. The elevated SMRs of various UCODs among younger PWD underscore the need for clinicians to pay particular attention to the medical care provided to these patients.

Blood-based biomarkers for Alzheimer's disease: a multicenter-based cross-sectional and longitudinal study in China

Discrepancies in diagnostic biomarkers for Alzheimer's Disease (AD) may arise from racial disparities, risk factors, or lifestyle differences. Moreover, there has been a lack of systematic and multicenter studies to evaluate baselines of the AD biomarkers in Chinese populations. Thus, there is an urgent need for research to investigate the effectiveness of blood biomarkers for AD, specifically in the Chinese Han population, using a multicenter approach. In the present multicenter-based cross-sectional and longitudinal study, we evaluated 817 blood samples from 6 different clinical centers. We measured plasma amyloid beta (Aβ)-40, Aβ42, phosphorylated tau 181 (pTau), total tau (tTau), serum neurofilament light (NFL), and glial fibrillary acidic protein (GFAP). Additionally, 18F-florbetapir positron electron tomography and magnetic resonance imaging were also performed. A combination of the APOE genotype with plasma pTau and serum GFAP demonstrated exceptional performance in distinguishing Aβ status. Furthermore, baseline GFAP levels exhibited a strong association with cognitive decline over time and brain atrophy, with higher GFAP levels predicting a faster rate of neurodegeneration. In summary, these results validate the practicality of blood biomarkers in the Chinese Han population, encompassing various regions within China. Additionally, they emphasize the potential of pTau and GFAP as non-invasive methods for detecting and screening AD at an early stage.

Implication of the cooking oil-peroxidation product "hydroxynonenal" for Alzheimer's disease

Aldehyde dehydrogenase 2 (ALDH2) is a mitochondrial enzyme that reduces cell injuries via detoxification of lipid-peroxidation product, 4-hydroxy-2-nonenal (hydroxynonenal). It is generated exogenously via deep-frying of linoleic acid-rich cooking oils and/or endogenously via oxidation of fatty acids involved in biomembranes. Although its toxicity for human health is widely accepted, the underlying mechanism long remained unknown. In 1998, Yamashima et al. have formulated the "calpain-cathepsin hypothesis" as a molecular mechanism of ischemic neuronal death. Subsequently, they found that calpain cleaves Hsp70.1 which became vulnerable after the hydroxynonenal-induced carbonylation at the key site Arg469. Since it is the pivotal aberration that induces lysosomal membrane rupture, they suggested that neuronal death in Alzheimer's disease similarly occurs by chronic ischemia via the calpain-cathepsin cascade triggered by hydroxynonenal. For nearly three decades, amyloid β (Aβ) peptide was thought to be a root substance of Alzheimer's disease. However, because of both the insignificant correlations between Aβ depositions and occurrence of neuronal death or dementia, and the negative results of anti-Aβ medicines tested so far in the patients with Alzheimer's disease, the strength of the "amyloid cascade hypothesis" has been weakened. Recent works have suggested that hydroxynonenal is a mediator of programmed cell death not only in the brain, but also in the liver, pancreas, heart, etc. Increment of hydroxynonenal was considered an early event in the development of Alzheimer's disease. This review aims at suggesting ways out of the tunnel, focusing on the implication of hydroxynonenal in this disease. Herein, the mechanism of Alzheimer neuronal death is discussed by focusing on Hsp70.1 with a dual function as chaperone protein and lysosomal stabilizer. We suggest that Aβ is not a culprit of Alzheimer's disease, but merely a byproduct of autophagy/lysosomal failure resulting from hydroxynonenal-induced Hsp70.1 disorder. Enhancing ALDH2 activity to detoxify hydroxynonenal emerges as a promising strategy for preventing and treating Alzheimer's disease.

Kidney function, albuminuria, and their modification by genetic factors and risk of incident dementia in UK Biobank

BACKGROUND

Associations between kidney function and dementia risk are inconclusive. Chronic kidney disease (CKD) severity is determined by levels of both estimated glomerular filtration rate (eGFR) and the urine albumin to creatinine ratio (ACR). However, whether there is a graded increase in dementia risk for worse eGFR in each ACR category is unclear. Also, whether genetic risk for dementia impacts the associations is unknown. The current study aims to investigate the associations between eGFR and albuminuria with dementia risk both individually and jointly, whether the associations vary by different follow-up periods, and whether genetic factors modified the associations.

METHODS

In 202,702 participants aged ≥ 60 years from the UK Biobank, Cox proportional-hazards models were used to examine the associations between eGFR and urine albumin creatinine ratio (ACR) with risk of incident dementia. GFR was estimated based on serum creatinine, cystatin C, or both. The models were restricted to different follow-up periods (< 5 years, 5-10 years, and ≥ 10 years) to investigate potential reverse causation.

RESULTS

Over 15 years of follow-up, 6,042 participants developed dementia. Decreased kidney function (eGFR < 60 ml/min/1.73m2) was associated with an increased risk of dementia (Hazard Ratio [HR] = 1.42, 95% Confidence Interval [CI] 1.28-1.58), compared to normal kidney function (≥ 90 ml/min/1.73m2). The strength of the association remained consistent when the models were restricted to different periods of follow-up. The HRs for incident dementia were 1.16 (95% CI 1.07-1.26) and 2.24 (95% CI 1.79-2.80) for moderate (3-30 mg/mmol) and severely increased ACR (≥ 30 mg/mmol) compared to normal ACR (< 3 mg/mmol). Dose-response associations were observed when combining eGFR and ACR, with those in the severest eGFR and ACR group having the greatest risk of dementia (HR = 4.70, 95% CI 2.34-9.43). APOE status significantly modified the association (p = 0.04), with stronger associations observed among participants with a lower genetic risk of dementia. There was no evidence of an interaction between kidney function and non-APOE polygenic risk of dementia with dementia risk (p = 0.42).

CONCLUSIONS

Kidney dysfunction and albuminuria were individually and jointly associated with higher dementia risk. The associations were greater amongst participants with a lower genetic risk of dementia based on APOE, but not non-APOE polygenic risk.

New evidence of trends in cognitive function among middle-aged and older adults in China, 2011-2018: an age-period-cohort analysis

BACKGROUND

Increasing evidence from high-income countries suggests the risk of cognitive impairment has been declining recently. However, related studies in China have rarely been done, and the results are inconsistent. We analyze the trends in cognitive function among middle-aged and older adults in China between 2011 and 2018.

METHODS

We used data from four waves of the China Health and Retirement Longitudinal Study (CHARLS), including 48918 individuals aged 45 years and older. Cognitive function was assessed using the CHARLS cognitive measures containing episodic memory, orientation, attention, and visuospatial abilities. The hierarchical age-period-cohort (APC) model was used to quantify the separate age, period, and cohort effects on trends in cognitive function.

RESULTS

The study sample's ages ranged from 45 to 105 years (Mean = 59.2, SD = 9.4). Cognitive function declined with age net of period and cohort effects, an apparent acceleration in the rate of cognitive decline after age 65 was found adjusting for individual characteristics. Although period effects on trends in cognitive function remained stable during the study period, hierarchical APC models demonstrated significant cohort variations. Independent of age and period effects, there was a fluctuating trend across cohorts before 1960 and an overall decline across successive cohorts.

CONCLUSIONS

Our study indicates that the age effect remains the most crucial factor regarding cognitive decline. Moreover, results demonstrate that cohorts living in social upheaval leading to educational deprivation and/or nutritional deficiency in early life may face a higher risk for cognitive deterioration later in life. Such findings indicate that dementia prevention from a life course perspective and cohort-specific strategies are critical to alleviating the future public-health burdens related to cognitive aging. Ongoing attention should be paid to the role of cross-cohort differences in education on cohort trends in cognition in countries like China that are aging rapidly and have a late start in educational expansion compared to other countries. Other factors, such as environmental stimulation, need to be noticed in younger cohorts.

Emergency department visits and associated factors among people with dementia residing in nursing homes in Taiwan: a one-year cohort study

BACKGROUND

Residing in a nursing home (NH) may increase emergency department (ED) utilization in patients with dementia; however, evidence regarding the status of and predictors for ED utilization of NH residents with dementia remains unclear, especially in Asia. This study aimed to assess the incidence density of ED visits and associated factors for the risk of ED utilization among NH residents with dementia.

METHODS

This one-year cohort study followed 6595 NH residents with dementia aged ≧ 40 years from Taiwan's National Health Insurance Research Database between 2012 and 2014. The Andersen-Gill extension of Cox regression analysis with death as a competing risk was applied to investigate the association of the risk of all causes and the most common causes of ED utilization with the predisposing, enabling, and need factors as defined by the Andersen model.

RESULTS

All participants encountered 9254 emergency visits in the 5371.49 person-years observed, representing incidence densities of ED visits of 1722.80 per 1000 person-years. Among them, respiratory disease was the most common cause of ED visits. The significant predictors for the risk of all-cause and respiratory-cause ED visits included: (1) predisposing factors (i.e., age and gender); (2) enabling factors (i.e., regional variables); and (3) need factors (i.e., prolonged ventilator dependence and comorbidity status).

CONCLUSIONS

Predisposing, enabling, and need factors could influence ED visits among studies patients. NH providers should consider these factors to develop strategies for reducing ED utilization.

Exploring Temporal and Sex-Linked Dysregulation in Alzheimer's Disease Phospho-Proteome

This study aims to characterize dysregulation of phosphorylation for the 5XFAD mouse model of Alzheimer's disease (AD). Employing global phosphoproteome measurements, we analyze temporal (3, 6, 9 months) and sex-dependent effects on mouse hippocampus tissue to unveil molecular signatures associated with AD initiation and progression. Our results indicate 1.9 to 4.4 times higher phosphorylation prevalence compared to protein expression across all time points, with approximately 4.5 times greater prevalence in females compared to males at 3 and 9 months. Moreover, our findings reveal consistent phosphorylation of known AD biomarkers APOE and GFAP in 5XFAD mice, alongside novel candidates BIG3, CLCN6 and STX7, suggesting their potential as biomarkers for AD pathology. In addition, we identify PDK1 as a significantly dysregulated kinase at 9 months in females, and the regulation of gap junction activity as a key pathway associated with Alzheimer's disease across all time points. AD-Xplorer, the interactive browser of our dataset, enables exploration of AD-related changes in phosphorylation, protein expression, kinase activities, and pathways. AD-Xplorer aids in biomarker discovery and therapeutic target identification, emphasizing temporal and sex-specific nature of significant phosphoproteomic signatures. Available at: https://yilmazs.shinyapps.io/ADXplorer.

Dementia and the history of disease in older adults in community

INTRODUCTION

Many studies have revealed the effect of medical history on dementia. The aim of this study was to explore the relationship between the history of disease and onset of dementia.

METHODS

This was a multi-center, cross-sectional study, with 2595 older adults enrolled. The onset of dementia was evaluated with Revised Hasegawa Dementia Scale (HDS-R). The diagnosed diseases after the age of 40 of the participants were investigated, including respiratory system diseases, digestive system diseases, cardiovascular diseases, endocrine disorders, genitourinary system diseases, nervous system disease, sensory system diseases, dental/oral diseases, bone/joint diseases and mental illnesses.

RESULTS

Data of 2458 older adults were analyzed. Univariate analysis showed that diabetes, thyroid disease, mental illness, hearing loss, stroke, dental/oral disease, Denture use, fracture/osteoporosis, kidney disease and number of diseases were risk factors for dementia. After controlling for demographic sociological variables, diabetes, dental/oral disease, and denture use were independent risk factors for dementia. Thyroid disease (P = 0.313), mental illnesses (P = 0.067), hearing loss (P = 0.595), stroke (P = 0.538), fractures/osteoporosis (P = 0.069), kidney disease (P = 0.168) were no longer significant to dementia.

CONCLUSION

Diabetes, dental/oral disease and denture use were main risk factors for dementia.

Disease severity and mortality in Alzheimer's disease: an analysis using the U.S. National Alzheimer's Coordinating Center Uniform Data Set

BACKGROUND

Evidence on the relative risk of death across all stages of Alzheimer's disease (AD) is lacking but greatly needed for the evaluation of new interventions. We used data from the Uniform Data Set (UDS) of the National Alzheimer's Coordinating Center (NACC) to assess the expected survival of a person progressing to a particular stage of AD and the relative risk of death for a person in a particular stage of AD compared with cognitively normal (CN) people.

METHODS

This was a retrospective observational cohort study of mortality and its determinants in participants with incident mild cognitive impairment (MCI) due to AD or AD dementia compared with CN participants. Overall survival and hazard ratios of all-cause mortality in participants ≥ 50 years of age with clinically assessed or diagnosed MCI due to AD, or mild, moderate, or severe AD dementia, confirmed by Clinical Dementia Rating scores, versus CN participants were estimated, using NACC UDS data. Participants were followed until death, censoring, or until information to determine disease stage was missing.

RESULTS

Aged between 50 and 104 years, 12,414 participants met the eligibility criteria for the study. Participants progressing to MCI due to AD or AD dementia survived a median of 3-12 years, with higher mortality observed in more severe stages. Risk of death increased with the severity of AD dementia, with the increase significantly higher at younger ages. Participants with MCI due to AD and CN participants had a similar risk of death after controlling for confounding factors.

CONCLUSIONS

Relative all-cause mortality risk increases with AD severity, more so at younger ages. Mortality does not seem to be higher for those remaining in MCI due to AD. Findings might imply potential benefit of lower mortality if preventing or delaying the progression of AD is successful, and importantly, this potential benefit might be greater in relatively younger people. Future research should replicate our study in other samples more representative of the general US population as well as other populations around the world.

The Protective Effect of Vitamin D on Dementia Risk in Hemodialysis Patients

BACKGROUND

Patients with end-stage renal disease (ESRD) undergoing hemodialysis are at an elevated risk of developing dementia, potentially linked to the high prevalence of vitamin D deficiency in this population, which may contribute to cognitive impairment. Nevertheless, the impact of vitamin D supplementation on the risk of dementia in hemodialysis patients remains uncertain, necessitating further investigation to elucidate the potential benefits of vitamin D intervention in this vulnerable group.

METHODS

In this propensity-score-matched comparative cohort study, we sought to assess the impact of vitamin D supplementation on the occurrence of dementia in patients with end-stage renal disease (ESRD) undergoing hemodialysis. A total of 1424 patients were included and matched 1:1 using propensity scores. The study population was divided into two groups: those receiving vitamin D supplementation at a dose of ≥70 μg/week and those without any supplementation. The primary outcome of interest was the incidence of dementia. We calculated adjusted hazard ratios (aHRs) to examine the association between vitamin D supplementation and the risk of dementia while controlling for relevant covariates.

RESULTS

The adjusted hazard ratio (aHR) comparing vitamin D supplementation to no supplementation was 0.44 (95% CI 0.29-0.69; p < 0.0001), demonstrating a significant decrease in the risk of dementia associated with vitamin D supplementation. The aHRs for vitamin D supplementation at different dose ranges (70-105, 106-350, 351-1000, and >1000 μg/week) were 0.51, 0.49, 0.43, and 0.41, respectively (p for trend < 0.0001). These findings suggest a potential dose-dependent relationship between vitamin D supplementation and the reduction of dementia risk.

CONCLUSIONS

In our study, we found that vitamin D supplementation at doses of ≥70 μg/week significantly reduced the risk of dementia in patients with end-stage renal disease (ESRD) undergoing hemodialysis. Furthermore, our results indicated a dose-dependent effect, with higher doses of supplementation correlating with a greater reduction in dementia risk. These findings underscore the potential of vitamin D supplementation as a preventive approach for cognitive impairment in this high-risk population.

Uncovering Diverse Mechanistic Spreading Pathways in Disease Progression of Alzheimer's Disease

Background

The AT[N] research framework focuses on three major biomarkers in Alzheimer's disease (AD): amyloid-β deposition (A), pathologic tau (T), and neurodegeneration [N].

Objective

We hypothesize that the diverse mechanisms such as A⟶T and A⟶[N] pathways from one brain region to others, may underlie the wide variation in clinical symptoms. We aim to uncover the causal-like effect of regional AT[N] biomarkers on cognitive decline as well as the interaction with non-modifiable risk factors such as age and APOE4.

Methods

We apply multi-variate statistical inference to uncover all possible mechanistic spreading pathways through which the aggregation of an upstream biomarker (e.g., increased amyloid level) in a particular brain region indirectly impacts cognitive decline, via the cascade build-up of a downstream biomarker (e.g., reduced metabolism level) in another brain region. Furthermore, we investigate the survival time for each identified region-to-region pathological pathway toward the AD onset.

Results

We have identified a collection of critical brain regions on which the amyloid burdens exert an indirect effect on the decline in memory and executive function (EF) domain, being mediated by the reduction of metabolism level at other brain regions. APOE4 status has been found not only involved in many A⟶N mechanistic pathways but also significantly contributes to the risk of developing AD.

Conclusion

Our major findings include 1) the region-to-region A⟶N⟶MEM and A⟶N⟶MEM pathways exhibit distinct spatial patterns; 2) APOE4 is significantly associated with both direct and indirect effects on the cognitive decline while sex difference has not been identified in the mediation analysis.

Prevalence of treated patients with Alzheimer's disease: current trends and COVID-19 impact

BACKGROUND

There are few updated studies on the prevalence and management of Alzheimer's disease (AD), which could be underdiagnosed or undertreated. The COVID-19 pandemic may have worsened the deficiencies in the diagnosis and treatment of these patients. Electronic medical records (EMR) offer an opportunity to assess the impact and management of medical processes and contingencies in the population.

OBJECTIVE

To estimate AD prevalence in Spain over a 6-year period, based on treated patients, according to usual clinical practice. Additionally, to describe the management of AD-treated patients and the evolution of that treatment during the 2020 COVID-19 pandemic.

METHODS

Retrospective study using the Spanish IQVIA EMR database. Patients treated with donepezil, galantamine, rivastigmine, and/or memantine were included in the study. Annual AD prevalence (2015-2020) was estimated and extrapolated to the national population level. Most frequent treatments and involved specialties were described. To assess the effect of COVID-19, the incidence of new AD cases in 2020 was calculated and compared with newly diagnosed cases in 2019.

RESULTS

Crude AD prevalence (2015-2020) was estimated at 760.5 per 100,000 inhabitants, and age-standardized prevalence (2020) was 664.6 (male 595.7, female 711.0). Monotherapy was the most frequent way to treat AD (86.2%), in comparison with dual therapy (13.8%); rivastigmine was the most prescribed treatment (37.3%), followed by memantine (36.4%) and donepezil (33.0%). Rivastigmine was also the most utilized medication in newly treated patients (46.7%), followed by donepezil (29.8%), although donepezil persistence was longer (22.5 vs. 20.6 months). Overall, donepezil 10 mg, rivastigmine 9.5 mg, and memantine 20 mg were the most prescribed presentations. The incidence rate of AD decreased from 148.1/100,000 (95% confidence interval [CI] 147.0-149.2) in 2019 to 118.4/100,000 (95% CI 117.5-119.4) in 2020.

CONCLUSIONS

The obtained prevalence of AD-treated patients was consistent with previous face-to-face studies. In contrast with previous studies, rivastigmine, rather than donepezil, was the most frequent treatment. A decrease in the incidence of AD-treated patients was observed during 2020 in comparison with 2019, presumably due to the significant impact of the COVID-19 pandemic on both diagnosis and treatment. EMR databases emerge as valuable tools to monitor in real time the incidence and management of medical conditions in the population, as well as to assess the health impact of global contingencies and interventions.

Association of Fruit and Vegetable Consumption With Mild Cognitive Impairment in Low- and Middle-Income Countries

BACKGROUND

Inadequate fruit and vegetable intake may be associated with cognitive decline but its association with mild cognitive impairment (MCI; a preclinical stage of dementia) is largely unknown. Therefore, we examined the association of fruit and vegetable consumption with MCI among middle-aged and older adults from low- and middle-income countries (LMICs).

METHODS

Cross-sectional, nationally representative data from the WHO Study on global AGEing and adult health were analyzed. MCI was defined using the National Institute on Aging-Alzheimer's Association criteria. Quintiles of vegetable and fruit consumption were created based on the number of servings consumed on a typical day. Multivariable logistic regression analysis was conducted.

RESULTS

Data on 32 715 individuals aged ≥50 years were analyzed (mean [standard deviation] age 62.1 [15.6] years; 51.7% females). Greater fruit consumption was dose-dependently associated with lower odds for MCI. For example, the highest quintile (vs lowest) had 47% lower odds for MCI (odds ratio [OR] = 0.53; 95% confidence interval [CI] = 0.43-0.66). For vegetable consumption, compared to the lowest quintile, the second to fourth quintiles had significant 38%-44% lower odds for MCI but there was no significant difference for the highest quintile (OR = 0.82; 95% CI = 0.59-1.15).

CONCLUSIONS

Higher fruit and vegetable consumption was associated with lower odds for MCI among middle-aged and older adults from LMICs, but no significant differences were found between the highest and lowest quintiles of vegetable consumption. Future longitudinal studies are required to explore these findings in more depth, and mechanistic studies are required to elucidate on the observed possible U-shaped association between vegetable consumption and MCI.

Learning to PERSEVERE: A pilot study of peer mentor support and caregiver education in Lewy body dementia

BACKGROUND

Lewy Body Disease (LBD) is the second most common neurodegenerative disorder. Despite high family caregiver strain and adverse patient and caregiver outcomes, few interventions exist for LBD family caregivers. Based on a successful peer mentoring pilot study in advanced Parkinson's Disease, we revised the curriculum of this peer-led educational intervention incorporating LBD caregiver input.

OBJECTIVE

We assessed feasibility of a peer mentor-led educational intervention and its impact on LBD family caregivers' knowledge, dementia attitudes, and mastery.

METHODS

Using community-based participatory research, we refined a 16-week peer mentoring intervention and recruited caregivers online through national foundations. Experienced LBD caregiver mentors were trained and matched with newer caregiver mentees with whom they spoke weekly for 16 weeks, supported by the intervention curriculum. We measured intervention fidelity biweekly, program satisfaction, and change in LBD knowledge, dementia attitudes, and caregiving mastery before and after the 16-week intervention.

RESULTS

Thirty mentor-mentee pairs completed a median of 15 calls (range: 8-19; 424 total calls; median 45 min each). As satisfaction indicators, participants rated 95.3% of calls as useful, and at week 16, all participants indicated they would recommend the intervention to other caregivers. Mentees' knowledge and dementia attitudes improved by 13% (p < 0.05) and 7% (p < 0.001), respectively. Training improved mentors' LBD knowledge by 32% (p < 0.0001) and dementia attitudes by 2.5% (p < 0.001). Neither mentor nor mentee mastery changed significantly (p = 0.36, respectively).

CONCLUSIONS

This LBD caregiver-designed and -led intervention was feasible, well-received, and effective in improving knowledge and dementia attitudes in both seasoned and newer caregivers.

TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT04649164ClinicalTrials.gov Identifier: NCT04649164; December 2, 2020.

Biochemical profiling of berberine-enriched extract in aluminum chloride induced oxidative damage and neuroinflammation

Despite the numerous treatment strategies used for Alzheimer's disease (AD), only a few cholinesterase inhibitor drugs, such as memantine, are effective in symptomatically relieving the hallmarks of AD, providing momentary recovery of memory and cognitive decline. These available drugs do not treat the underlying causes of AD, and their chronic use is associated with serious adverse effects and disease progression. Berberine is an isoquinoline alkaloid that has been reported to possess therapeutic potential against AD. Therefore, its activity was evaluated against an aluminum chloride (AlCl3)-induced AD rat model, and a berberine-enriched extract (BEE) was used to determine if its activity is equivalent to pure berberine (PB). The rats were administered 300 mg/kg of oral AlCl3 to induce AD and were then treated with oral PB at a dosage of 50 mg/kg, BEE at a dosage of 50 mg/kg, and rivastigmine at a dosage of 1 mg/kg as a standard drug for 21 days. In this study, various parameters were assessed to evaluate cognitive functions, such as behavioral analysis, antioxidant enzyme levels, acetylcholinesterase (AChE) activity, proinflammatory cytokine levels, real-time polymerase chain reaction (RT-PCR) analysis of different biomarkers (AChE, IL-1α, IL-1β, BACE-1, TNF-α) linked to AD, and histopathological changes in the rats' brains. After 21 days, the disease control group showed a significant decline in cognitive function, decreased levels of antioxidant enzymes, upregulated activity of the AChE enzyme, increased levels of proinflammatory cytokines, and marked elevation in mRNA expression of AD-associated biomarkers. On the other hand, the treatment groups showed significant improvements in memory deficits, elevated levels of antioxidant enzymes, reduced levels of proinflammatory cytokines, decreased AChE activity, and significant downregulation of the expression of predefined biomarkers. Histological examination of the treatment groups showed less neuroinflammation and fewer amyloid plaques compared to the disease control group. In conclusion, both PB and BEE have comparable neuroprotective potential to mitigate the pathological hallmarks of AD. However, controlled clinical trials are needed to assess their efficacy and safety.

Exploring the Causal Relationship Between Telomere Biology and Alzheimer's Disease

Telomeres, also known as the "protective caps" of our chromosomes, shorten with each cell cycle due to the end replication problem. This process, termed telomere attrition, is associated with many age-related disorders, such as Alzheimer's disease (AD). Despite the numerous studies conducted in this field, the role of telomere attrition in the onset of the disease remains unclear. To investigate the causal relationship between short telomeres and AD, this review aims to highlight the primary factors that regulate telomere length and maintain its integrity, with an additional outlook on the role of oxidative stress, which is commonly associated with aging and molecular damage. Although some findings thus far might be contradictory, telomere attrition likely plays a crucial role in the progression of AD due to its close association with oxidative stress. The currently available treatments for AD are only symptomatic without affecting the progression of the disease. The components of telomere biology discussed in this paper have previously been studied as an alternative treatment option for several diseases and have exhibited promising in vitro and in vivo results. Hence, this should provide a basis for future research to develop a potential therapeutic strategy for AD. (Created with BioRender.com).

Antidiabetic agents as a novel treatment for Alzheimer's and Parkinson's disease

Therapeutic strategies for neurodegenerative disorders have commonly targeted individual aspects of the disease pathogenesis to little success. Neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD), are characterized by several pathological features. In AD and PD, there is an abnormal accumulation of toxic proteins, increased inflammation, decreased synaptic function, neuronal loss, increased astrocyte activation, and perhaps a state of insulin resistance. Epidemiological evidence has revealed a link between AD/PD and type 2 diabetes mellitus, with these disorders sharing some pathological commonalities. Such a link has opened up a promising avenue for repurposing antidiabetic agents in the treatment of neurodegenerative disorders. A successful therapeutic strategy for AD/PD would likely require a single or several agents which target the separate pathological processes in the disease. Targeting cerebral insulin signalling produces numerous neuroprotective effects in preclinical AD/PD brain models. Clinical trials have shown the promise of approved diabetic compounds in improving motor symptoms of PD and preventing neurodegenerative decline, with numerous further phase II trials and phase III trials underway in AD and PD populations. Alongside insulin signalling, targeting incretin receptors in the brain represents one of the most promising strategies for repurposing currently available agents for the treatment of AD/PD. Most notably, glucagon-like-peptide-1 (GLP-1) receptor agonists have displayed impressive clinical potential in preclinical and early clinical studies. In AD the GLP-1 receptor agonist, liraglutide, has been demonstrated to improve cerebral glucose metabolism and functional connectivity in small-scale pilot trials. Whilst in PD, the GLP-1 receptor agonist exenatide is effective in restoring motor function and cognition. Targeting brain incretin receptors reduces inflammation, inhibits apoptosis, prevents toxic protein aggregation, enhances long-term potentiation and autophagy as well as restores dysfunctional insulin signalling. Support is also increasing for the use of additional approved diabetic treatments, including intranasal insulin, metformin hydrochloride, peroxisome proliferator-activated nuclear receptor γ agonists, amylin analogs, and protein tyrosine phosphatase 1B inhibitors which are in the investigation for deployment in PD and AD treatment. As such, we provide a comprehensive review of several promising anti-diabetic agents for the treatment of AD and PD.

Comparative Analysis on the Policy Approaches in the National Dementia Plans of G7 Countries and Korea and Their Implementation

BACKGROUND

The World Health Organization (WHO) proposed a global action plan for dementia and aimed to have 75% of their member states formulating National Dementia Plans (NDPs) by 2025. The Organization for Economic Cooperation and Development (OECD) proposed the ten key objectives of dementia policy in 2015. Among previous studies on NDPs, few studies have investigated measures for proper implementation of NDPs. This study aimed to compare the implementation basis and specific action plans of NDPs between the G7 countries and South Korea.

METHODS

We investigated the measures for proper implementation of the NDPs of G7 countries and South Korea. To compare the specific policy approaches, the seven action areas of the WHO action plan and the ten key objectives of dementia policy proposed by the OECD were integrated into 11 targets (prevention, diagnosis, awareness, caregiver support, appropriate environments, long-term care, health service, end-of-life care, care coordination, research and technology, information systems).

RESULTS

Although most NDPs included specific action plans of the 11 targets, caregiver support, safe environments, healthcare services, and end-of-life care were lacking in some NDPs. For implementation, some countries reinforced the policy priority of their NDPs by timely updates, evaluation, legislations, or head-of-state leadership. However, only three countries had a legislative basis, and three countries included outcome measures in their latest NDP.

CONCLUSION

Effective measures for feasible implementation are needed. The WHO should promote not only the establishment of NDPs, but also their proper implementation.

The effects of high plasma levels of Aβ1-42 on mononuclear macrophage in mouse models of Alzheimer's disease

More and more evidences are proving that microglia play a crucial role in the pathogenesis of Alzheimer's disease (AD) and the plasma Aβ_1-42 levels significantly increased 15 years before the onset of dominantly inherited AD. However, the effects of high plasma levels of Aβ_1-42 on mononuclear macrophage, the peripheral counterparts of microglia, remain unclear. In the present study, we used APP/PS1 transgenic (Tg) mice and a parabiotic model of wild type (Wt) mice and Tg mice (Parabiotic Wt-Tg, Pa (Wt-Tg)) to investigate the effects of high plasma levels of Aβ_1-42 on peripheral mononuclear macrophage. Our results showed that in the early stage of Tg mice (7 months) and Pa (Wt-Tg) mice (4 months), the proportions of pro-inflammatory macrophages in peritoneal cavity, myeloid derived suppressor cells (MDSCs) in spleen, granulocyte-monocyte progenitors (GMPs) in bone marrow, and the plasma levels of interleukin-6 (IL-6) were significantly decreased. While the proportions of pro-inflammatory macrophages, MDSCs, GMPs, and the plasma levels of IL-6 and tumor necrosis factor (TNF)-α, as well as the numbers of bone marrow-derived macrophages (BMDMs) in mice brain were increased in the late stage of Tg mice (11 months) and Pa (Wt-Tg) mice (8 months). In addition, the proportions of monocytes in spleen and the proliferation of bone marrow cells (BMCs) were enhanced consistently, and the phagocytic function of macrophages kept stably after high plasma levels of Aβ_1-42 sustaining stimulation. These results demonstrated that high plasma levels of Aβ_1-42 play a biphasic regulating role at different stages of the disease, namely inhibiting effects on peripheral pro-inflammatory macrophages in the early stage of AD model, while promoting effects in the late stage of AD model. The mechanism behind this may be associated with their effects on MDSCs in spleen and myeloid progenitor cells in bone marrow. Therefore, intervening the effects of plasma Aβ_1-42 on pro-inflammatory macrophages might offer a new therapeutic approach to AD.

The effect of the leisure activities based on chess and cards for improving cognition of older adults: study protocol for a cluster randomized controlled trial

BACKGROUND

With the increase in age, the probability of cognitive impairment in the older people is increasing. More and more evidence shows that participating in leisure activities, especially chess and cards, is beneficial to the cognition and mental state of the older people. But the evidence for causal inference is limited. There is a need to conduct a fully powered randomized controlled trial (RCT) and long-term follow-up to test the effectiveness of intervention measures in improving cognitive function and mental state. This paper describes the methodology of a cluster RCT designed to determine the effect of chess and cards leisure activities on the cognitive function of the older people over 60 years old.

METHODS/DESIGN

A cluster RCT consisting of 8 clusters will be conducted in four regions of Ningxia, China (Helan, Litong, Qingtongxia, and Shapotou). Clusters will be randomly assigned to the advocacy intervention group, which is also delivered with free leisure activities tools (chess and cards), or the control group. A baseline survey will be conducted before the intervention. A mid-term and final survey will be carried out twelve and twenty-four months after the intervention, respectively. The primary outcome is a change in cognitive function, and the secondary outcomes are changes in anxiety, depression, and loneliness.

DISCUSSION

The results of this RCT will be helpful to (1) confirm the effectiveness of chess and cards leisure activities in improving the cognitive function of the older people over 60 years old; (2) determine the relationship between the frequency and duration of chess and cards leisure activities and cognitive function; (3) provide evidence of promoting participation in leisure activities through education campaigns and free provision of chess and cards tools; and (4) provide valuable information for successful aging.

TRIAL REGISTRATION

Chinese Clinical Trial Registry: ChiCTR2200066817. Registered on 19 December 2022.