Worldwide variation in the doubling time of Alzheimer's disease incidence rates

Associations between sex, body mass index and the individual microglial response in Alzheimer's disease

BACKGROUND AND OBJECTIVES

18-kDa translocator protein position-emission-tomography (TSPO-PET) imaging emerged for in vivo assessment of neuroinflammation in Alzheimer's disease (AD) research. Sex and obesity effects on TSPO-PET binding have been reported for cognitively normal humans (CN), but such effects have not yet been systematically evaluated in patients with AD. Thus, we aimed to investigate the impact of sex and obesity on the relationship between β-amyloid-accumulation and microglial activation in AD.

METHODS

49 patients with AD (29 females, all Aβ-positive) and 15 Aβ-negative CN (8 female) underwent TSPO-PET ([18F]GE-180) and β-amyloid-PET ([18F]flutemetamol) imaging. In 24 patients with AD (14 females), tau-PET ([18F]PI-2620) was additionally available. The brain was parcellated into 218 cortical regions and standardized-uptake-value-ratios (SUVr, cerebellar reference) were calculated. Per region and tracer, the regional increase of PET SUVr (z-score) was calculated for AD against CN. The regression derived linear effect of regional Aβ-PET on TSPO-PET was used to determine the Aβ-plaque-dependent microglial response (slope) and the Aβ-plaque-independent microglial response (intercept) at the individual patient level. All read-outs were compared between sexes and tested for a moderation effect of sex on associations with body mass index (BMI).

RESULTS

In AD, females showed higher mean cortical TSPO-PET z-scores (0.91 ± 0.49; males 0.30 ± 0.75; p = 0.002), while Aβ-PET z-scores were similar. The Aβ-plaque-independent microglial response was stronger in females with AD (+ 0.37 ± 0.38; males with AD - 0.33 ± 0.87; p = 0.006), pronounced at the prodromal stage. On the contrary, the Aβ-plaque-dependent microglial response was not different between sexes. The Aβ-plaque-independent microglial response was significantly associated with tau-PET in females (Braak-II regions: r = 0.757, p = 0.003), but not in males. BMI and the Aβ-plaque-independent microglial response were significantly associated in females (r = 0.44, p = 0.018) but not in males (BMI*sex interaction: F(3,52) = 3.077, p = 0.005).

CONCLUSION

While microglia response to fibrillar Aβ is similar between sexes, women with AD show a stronger Aβ-plaque-independent microglia response. This sex difference in Aβ-independent microglial activation may be associated with tau accumulation. BMI is positively associated with the Aβ-plaque-independent microglia response in females with AD but not in males, indicating that sex and obesity need to be considered when studying neuroinflammation in AD.

Individual regional associations between Aβ-, tau- and neurodegeneration (ATN) with microglial activation in patients with primary and secondary tauopathies

β-amyloid (Aβ) and tau aggregation as well as neuronal injury and atrophy (ATN) are the major hallmarks of Alzheimer's disease (AD), and biomarkers for these hallmarks have been linked to neuroinflammation. However, the detailed regional associations of these biomarkers with microglial activation in individual patients remain to be elucidated. We investigated a cohort of 55 patients with AD and primary tauopathies and 10 healthy controls that underwent TSPO-, Aβ-, tau-, and perfusion-surrogate-PET, as well as structural MRI. Z-score deviations for 246 brain regions were calculated and biomarker contributions of Aβ (A), tau (T), perfusion (N1), and gray matter atrophy (N2) to microglial activation (TSPO, I) were calculated for each individual subject. Individual ATN-related microglial activation was correlated with clinical performance and CSF soluble TREM2 (sTREM2) concentrations. In typical and atypical AD, regional tau was stronger and more frequently associated with microglial activation when compared to regional Aβ (AD: βT = 0.412 ± 0.196 vs. βA = 0.142 ± 0.123, p < 0.001; AD-CBS: βT = 0.385 ± 0.176 vs. βA = 0.131 ± 0.186, p = 0.031). The strong association between regional tau and microglia reproduced well in primary tauopathies (βT = 0.418 ± 0.154). Stronger individual associations between tau and microglial activation were associated with poorer clinical performance. In patients with 4RT, sTREM2 levels showed a positive association with tau-related microglial activation. Tau pathology has strong regional associations with microglial activation in primary and secondary tauopathies. Tau and Aβ related microglial response indices may serve as a two-dimensional in vivo assessment of neuroinflammation in neurodegenerative diseases.

New cases of dementia are rising in elderly populations in Wales, UK

Dementia is one of the most common diseases in elderly populations, and older populations are one of the fastest growing groups globally. Consequently, the number of people developing and living with dementia is likely to grow. Using longitudinal medical records from Wales, UK between 1999 and 2018, diagnoses of overall dementia and common subtypes were combined with demographic data to assess numbers of new and existing cases per year. Data extraction resulted in 161,186 diagnoses from 116,645 individuals. Mean age at diagnosis of dementia increased over this period, resulting in fewer younger people with the disease. New cases of dementia have risen, as has the number of people living with dementia. Individuals with dementia are also living longer, even accounting for their older age. This may present a challenge for healthcare systems as the number of elderly people living with dementia is expected to continue to grow.

Mesenchymal Stem Cells and Begacestat Mitigate Amyloid-β 25-35-Induced Cognitive Decline in Rat Dams and Hippocampal Deteriorations in Offspring

Alzheimer's disease (AD) is the most common cause of age-related neurodegeneration and cognitive decline. AD more commonly occurs in females than in males, so it is necessary to consider new treatments specifically targeting this population. The present study investigated the protective effects of Begacestat (γ-secretase inhibitor-953, GSI-953) and bone marrow-derived mesenchymal stem cells (BM-MSCs) during pregnancy on cognitive impairment in rat dams and neurodegeneration in offspring caused by the intracerebroventricular injection of Aβ 25-35 before pregnancy. The performances of dams injected with amyloid-β 25-35 (Aβ 25-35) during behavioral tests were significantly impaired. The offspring of Aβ 25-35-injected dams treated with BM-MSCs or GSI-953 showed a dramatically reduced number and size of activated microglial cells, enhancement in the processes length, and a decrease in the proinflammatory cytokine levels. Additionally, BM-MSC or GSI-953 therapy reduced Aβ 25-35-induced increases in tau phosphorylation and amyloid precursor protein levels in the neonates' hippocampus and elevated the lower levels of glycogen synthase kinase-3 and brain-derived neurotrophic factor; moreover, reversed Aβ 25-35-induced alterations in gene expression in the neonatal hippocampus. Finally, the treatments with BM-MSC or GSI-953 are globally beneficial against Aβ 25-35-induced brain alterations, particularly by suppressing neural inflammation, inhibiting microglial cell activation, restoring developmental plasticity, and increasing neurotrophic signaling.

Development of a latent dementia index in the aging, demographics, and memory study: Validation and measurement invariance by sex

Latent variable models can create a latent dementia index (LDI) using cognitive and functional ability to approximate dementia likelihood. The LDI approach has been applied across diverse cohorts. It is unclear whether sex affects its measurement properties. We use Wave A (2001-2003) of the Aging, Demographics, and Memory Study (n = 856). Multiple group confirmatory factor analysis (CFA) was used to test measurement invariance (MI) using informant-reported functional ability and cognitive performance tasks, which we group into verbal, nonverbal, and memory. Partial scalar invariance was found, allowing for testing sex differences in LDI means (MDiff = 0.38). The LDI correlated with consensus panel dementia diagnosis, Mini-Mental State Examination (MMSE), and dementia risk factors (low education, advanced age, and apolipoprotein ε4 [APOE-ε4] status) for men and women. The LDI validly captures dementia likelihood to permit estimation of sex differences. LDI sex differences indicate higher dementia likelihood in women, potentially due to social, environmental, and biological factors.

Modulating heart rate oscillation affects plasma amyloid beta and tau levels in younger and older adults

Slow paced breathing via heart rate variability (HRV) biofeedback stimulates vagus-nerve pathways that counter noradrenergic stress and arousal pathways that can influence production and clearance of Alzheimer's disease (AD)-related proteins. Thus, we examined whether HRV biofeedback intervention affects plasma Αβ40, Αβ42, total tau (tTau), and phosphorylated tau-181 (pTau-181) levels. We randomized healthy adults (N = 108) to use slow-paced breathing with HRV biofeedback to increase heart rate oscillations (Osc+) or to use personalized strategies with HRV biofeedback to decrease heart rate oscillations (Osc-). They practiced 20-40 min daily. Four weeks of practicing the Osc+ and Osc- conditions produced large effect size differences in change in plasma Aβ40 and Aβ42 levels. The Osc+ condition decreased plasma Αβ while the Osc- condition increased Αβ. Decreases in Αβ were associated with decreases in gene transcription indicators of β-adrenergic signaling, linking effects to the noradrenergic system. There were also opposing effects of the Osc+ and Osc- interventions on tTau for younger adults and pTau-181 for older adults. These results provide novel data supporting a causal role of autonomic activity in modulating plasma AD-related biomarkers.Trial registration: NCT03458910 (ClinicalTrials.gov); first posted on 03/08/2018.

Molecular Imaging of Neuroinflammation in Alzheimer's Disease and Mild Cognitive Impairment

Alzheimer's disease (AD) is the most prevalent neurocognitive disorder. Due to the ineffectiveness of treatments targeting the amyloid cascade, molecular biomarkers for neuroinflammation are attracting attention with increasing knowledge about the role of neuroinflammation in the pathogenesis of AD. This chapter will explore the results of studies using molecular imaging for diagnosing AD and mild cognitive impairment (MCI). Because it is critical to interpreting the data to understand which substances are targeted in molecular imaging, this chapter will discuss the two most significant targets, microglia and astrocytes, as well as the best-known radioligands for each. Then, neuroimaging results with PET neuroinflammation imaging will be reviewed for AD and MCI. Although a growing body of evidence has suggested that these molecular imaging biomarkers for neuroinflammation may have a role in the diagnosis of AD and MCI, the findings are inconsistent or cross-sectional, which indicates that it is difficult to apply the contents in practice due to the need for additional study. In particular, because the results of multiple interventions targeting neuroinflammation were inconclusive, molecular imaging markers for neuroinflammation can be used in combination with conventional markers to select appropriate patients for early intervention for neuroinflammation rather than as a single marker.

Preemptive Diagnosis of Alzheimer’s Disease in the Eastern Province of Saudi Arabia Using Computational Intelligence Techniques

Alzheimer’s Disease (AD) is a silent disease that causes the brain cells to die progressively, influencing consciousness, behavior, planning ability, and language to name a few. AD increases exponentially with aging, where it doubles every 5-6 years, causing profound implications, such as swallowing difficulties and losing the ability to speak before death. According to the Ministry of Health in Saudi Arabia, AD patients will triple by 2060 to reach 14 million patients worldwide. The rapid rise of patients is caused by the silent progress of the disease, leading to late diagnosis as the symptoms will not be distinguished from normal aging affect. Moreover, with the current medical capabilities, it is impossible to confirm AD with 100% certainty via specific medical examinations. The literature review revealed that most recent publications used images to diagnose AD, which is insufficient for local hospitals with limited imaging capabilities. Other studies that used clinical and demographical data failed to achieve adequate results. Consequently, this study aims to preemptively predict AD in Saudi Arabia by employing machine learning (ML) techniques. The dataset was acquired from King Fahad Specialist Hospital (KFSH) in Dammam, Saudi Arabia, containing standard clinical tests for 152 patients. Four ML algorithms, namely, support vector machine (SVM), k-nearest neighbors (k-NN), Adaptive Boosting (AdaBoost), and eXtreme Gradient Boosting (XGBoost), were employed to preemptively diagnose the disease. The empirical results demonstrated the robustness of SVM in the pre-emptive diagnosis of AD with accuracy, precision, recall, and area under the receiver operating characteristics (AUROC) of 95.56%, 94.70%, 97.78%, and 0.97, respectively, with 13 features after applying the sequential forward feature selection technique. This model can assist the medical staff in controlling the progression of the disease at low costs.

Prevalence of Alzheimer's disease and related dementias among veterans experiencing housing insecurity

INTRODUCTION

Housing insecure veterans are aging, but the prevalence of Alzheimer's disease and related dementias (AD/ADRD) in the population is unknown.

METHODS

We calculated the prevalence of AD/ADRD diagnoses in 2018 among veterans that experienced homelessness, were at-risk for homelessness, or were stably housed. We determined acute care (emergency department, hospitalizations, psychiatric hospitalizations), and any long-term care (nursing home, and community-based) use by housing status among veterans with an AD/ADRD diagnosis.

RESULTS

The overall prevalence of AD/ADRD diagnoses for homeless, at-risk, and stably housed veterans was 3.66%, 13.48%, and 3.04%, respectively. Housing insecure veterans with AD/ADRD used more acute care, and were more likely to have a nursing home admission compared to stably housed veterans. At risk, but not homeless veterans, were more likely to use US Department of Veterans Affairs-paid home and community-based care than stably housed veterans.

DISCUSSION

The prevalence of AD/ADRD diagnoses is greater among housing insecure veterans than stably housed veterans.

Alzheimer's Disease: A Silent Pandemic - A Systematic Review on the Situation and Patent Landscape of the Diagnosis

BACKGROUND

Alzheimer's disease (AD) is characterized by cognitive impairment, tau protein deposits, and amyloid beta plaques. AD impacted 44 million people in 2016, and it is estimated to affect 100 million people by 2050. AD is disregarded as a pandemic compared with other diseases. To date, there is no effective treatment or diagnosis.

OBJECTIVE

We aimed to discuss the current tools used to diagnose COVID-19, to point out their potential to be adapted for AD diagnosis, and to review the landscape of existing patents in the AD field and future perspectives for AD diagnosis.

METHOD

We carried out a scientific screening following a research strategy in PubMed; Web of Science; the Derwent Innovation Index; the KCI-Korean Journal Database; SciELO; the Russian Science Citation index; and the CDerwent, EDerwent, and MDerwent index databases.

RESULTS

A total of 326 from 6,446 articles about AD and 376 from 4,595 articles about COVID-19 were analyzed. Of these, AD patents were focused on biomarkers and neuroimaging with no accurate, validated diagnostic methods, and only 7% of kit development patents were found. In comparison, COVID-19 patents were 60% about kit development for diagnosis; they are highly accurate and are now commercialized.

CONCLUSION

AD is still neglected and not recognized as a pandemic that affects the people and economies of all nations. There is a gap in the development of AD diagnostic tools that could be filled if the interest and effort that has been invested to tackle the COVID-19 emergency could also be applied for innovation.

Chronic PPARγ Stimulation Shifts Amyloidosis to Higher Fibrillarity but Improves Cognition

We undertook longitudinal β-amyloid positron emission tomography (Aβ-PET) imaging as a translational tool for monitoring of chronic treatment with the peroxisome proliferator-activated receptor gamma (PPARγ) agonist pioglitazone in Aβ model mice. We thus tested the hypothesis this treatment would rescue from increases of the Aβ-PET signal while promoting spatial learning and preservation of synaptic density. Here, we investigated longitudinally for 5 months PS2APP mice (N = 23; baseline age: 8 months) and App^NL–G–F mice (N = 37; baseline age: 5 months) using Aβ-PET. Groups of mice were treated with pioglitazone or vehicle during the follow-up interval. We tested spatial memory performance and confirmed terminal PET findings by immunohistochemical and biochemistry analyses. Surprisingly, Aβ-PET and immunohistochemistry revealed a shift toward higher fibrillary composition of Aβ-plaques during upon chronic pioglitazone treatment. Nonetheless, synaptic density and spatial learning were improved in transgenic mice with pioglitazone treatment, in association with the increased plaque fibrillarity. These translational data suggest that a shift toward higher plaque fibrillarity protects cognitive function and brain integrity. Increases in the Aβ-PET signal upon immunomodulatory treatments targeting Aβ aggregation can thus be protective.

Combined Motor and Cognitive Rehabilitation: The Impact on Motor Performance in Patients with Mild Cognitive Impairment. Systematic Review and Meta-Analysis

Mild cognitive impairment (MCI), a neurodegenerative disease leading to Alzheimer’s disease or dementia, is often associated with physical complaints. Combined physical and cognitive training (PCT) has been investigated to see the effects on cognitive function, but its impact on motor functions and activities of daily living has not been explored yet. The combination of physical and cognitive training may be a valuable non-pharmacological intervention that could preserve motor function and quality of life (QoL). We aimed, therefore, to analyze if combined PCT is effective at improving motor performance in patients with an MCI. A systematic electronic literature search and a meta-analysis were conducted. The following criteria were compulsory for inclusion in the study: (1) randomized controlled trial design; (2) combined PCT compared to motor training alone or no intervention; (3) motor outcomes as a study’s end point. Nine articles met the inclusion criteria. Results showed that PCT significantly enhances balance compared to motor training alone (SMD 0.56; 95% CI 0.07 to 1.06; I² = 59%; 160 participants), whereas a significant improvement was found for mobility in the PCT group when compared to no intervention (MD −1.80; 95% CI −2.70 to −0.90; I² = 0%; 81 participants). However, there is no evidence that people with MCI experience an increase in gait speed and QoL at the end of their practice sessions. Further investigation with larger samples and a longer period of monitoring after intervention should be undertaken.

Long-term associations between amyloid positron emission tomography, sex, apolipoprotein E and incident dementia and mortality among individuals without dementia: hazard ratios and absolute risk

Dementia and mortality rates rise inexorably with age and consequently interact. However, because of the major logistical difficulties in accounting for both outcomes in a defined population, very little work has examined how risk factors and biomarkers for incident dementia are influenced by competing mortality. The objective of this study was to examine long-term associations between amyloid PET, APOE ɛ4, sex, education and cardiovascular/metabolic conditions, and hazard and absolute risk of dementia and mortality in individuals without dementia at enrolment. Participants were enrolled in the Mayo Clinic Study of Aging, a population-based study of cognitive ageing in Olmsted County, MN, USA. All were without dementia and were age 55-92 years at enrolment and were followed longitudinally. Predictor variables were amyloid PET, APOE ɛ4 status, sex, education, cardiovascular/metabolic conditions and age. The main outcomes were incident dementia and mortality. Multivariable, multi-state models were used to estimate mortality and incident dementia rates and absolute risk of dementia and mortality by predictor variable group. Of the 4984 participants in the study, 4336 (87%) were cognitively unimpaired and 648 (13%) had mild cognitive impairment at enrolment. The median age at enrolment was 75 years; 2463 (49%) were women. The median follow-up time was 9.4 years (7.5 years after PET). High versus normal amyloid (hazard ratio 2.11, 95% confidence interval 1.43-2.79), APOE ɛ4 (women: hazard ratio 2.24, 95% confidence interval 1.80-2.77; men: hazard ratio 1.37, 95% confidence interval 1.09-1.71), older age and two additional cardiovascular/metabolic conditions (hazard ratio 1.37, 95% confidence interval 1.22-1.53) were associated with the increased hazard of dementia (all P < 0.001). Among APOE ɛ4 carriers with elevated amyloid, remaining lifetime risk of dementia at age 65 years was greater in women [74% (95% confidence interval 65-84%) high and 58% (95% confidence interval 52-65%) moderate amyloid], than men [62% (95% confidence interval 52-73%) high and 44% (95% confidence interval 35-53%) moderate amyloid]. Overall, the hazard and absolute risk of dementia varied considerably by predictor group. The absolute risk of dementia associated with predictors characteristic of Alzheimer's disease was greater in women than men while at the same time the combination of APOE ɛ4 non-carrier with normal amyloid was more protective in women than men. This set of findings may be attributed in part to different biological effects and in part to lower mortality rates in women.

DOTA: Deep Learning Optimal Transport Approach to Advance Drug Repositioning for Alzheimer's Disease

Alzheimer's disease (AD) is the leading cause of age-related dementia, affecting over 5 million people in the United States and incurring a substantial global healthcare cost. Unfortunately, current treatments are only palliative and do not cure AD. There is an urgent need to develop novel anti-AD therapies; however, drug discovery is a time-consuming, expensive, and high-risk process. Drug repositioning, on the other hand, is an attractive approach to identify drugs for AD treatment. Thus, we developed a novel deep learning method called DOTA (Drug repositioning approach using Optimal Transport for Alzheimer's disease) to repurpose effective FDA-approved drugs for AD. Specifically, DOTA consists of two major autoencoders: (1) a multi-modal autoencoder to integrate heterogeneous drug information and (2) a Wasserstein variational autoencoder to identify effective AD drugs. Using our approach, we predict that antipsychotic drugs with circadian effects, such as quetiapine, aripiprazole, risperidone, suvorexant, brexpiprazole, olanzapine, and trazadone, will have efficacious effects in AD patients. These drugs target important brain receptors involved in memory, learning, and cognition, including serotonin 5-HT2A, dopamine D2, and orexin receptors. In summary, DOTA repositions promising drugs that target important biological pathways and are predicted to improve patient cognition, circadian rhythms, and AD pathogenesis.

Prevalence of Constipation in Elderly and Its Association With Dementia and Mild Cognitive Impairment: A Cross-Sectional Study

Background

Constipation and dementia have similar epidemiological characteristics. Changes in intestinal flora and characteristics of the brain-gut axis play roles in the pathogeneses of the two diseases, suggesting that there may be a close connection between the two. Most of the studies on constipation in dementia patients have focused on the population with α-synucleinopathies [Parkinson’s disease dementia (PDD), dementia with Lewy bodies (DLB)]. Few studies have reported the prevalence of constipation in all-cause dementia and mild cognitive impairment (MCI) populations.

Objective

To assess the prevalence of constipation in patients with all-cause dementia and MCI subtypes and to explore the association between constipation with dementia and MCI subtypes.

Methods

From May 2019 to December 2019, we conducted a population-based cross-sectional survey. A total of 11,743 participants aged 65 or older from nine cities in China were surveyed. Participants underwent a series of clinical examinations and neuropsychological measurements. Constipation, dementia, MCI and MCI subtype were diagnosed according to established criteria through standard diagnostic procedures.

Results

The overall age- and sex-adjusted prevalence of constipation in individuals aged 65 years and older was 14.8% (95% CI, 14.6–15.0). The prevalence rates of constipation were19.2% (95% CI, 17.3–21.0), 19.1% (95% CI, 16.8–21.5), 14.4% (95% CI, 12.8–15.9), and 13.8% (95% CI, 13.0–14.6) in the dementia, non-amnestic (na)-MCI, amnestic (a)-MCI and normal cognition populations, respectively. Multivariate logistic regression analysis showed that higher prevalence of constipation was associated with dementia (p = 0.0.032, OR = 1.18, 95% CI: 1.02–1.38) and na-MCI (p = 0.003, OR = 1.30, 95% CI: 1.09–1.54).

Conclusion

The present study found a high prevalence of constipation in elderly individuals in China, and higher in patients with dementia and na-MCI.

The Role of Inflammasomes in the Pathogenesis of Neurodegenerative Diseases

Abstract—Protein misfolding and accumulation of protein aggregates is a distinctive feature of most neurodegenerative diseases. They lead to disruption of cellular homeostasis, loss of synaptic connections, and therefore cellular apoptosis. It has been demonstrated that some innate immune responses play an important role in the emergence and progression of neurodegenerative diseases. Inflammasomes are components of innate immunity that play a major role in the maintenance of chronic inflammation. Inflammasomes function as intracellular sensors, detecting both exogenous and endogenous stimuli. They also take part in caspase-1 activation and the synthesis of pro-inflammatory cytokines. In the central nervous system (CNS), inflammasomes are predominantly expressed by microglia, the key cells of innate immunity responsible for activation and maintenance of inflammation. In addition to microglia, inflammasomes can be expressed and activated by astrocytes and neurons, as well as infiltrating myeloid cells. Understanding the mechanisms of activation and functioning of inflammasomes is crucial for the development of novel drugs targeted at modulation of the immune response associated with their excessive activation. This review provides up-to-date information on the inflammasome structure and mechanisms of action, the role of protein misfolding, aggregation and the influence of these factors on inflammasome activation, as well as potential therapeutic targets in neurodegenerative diseases.

Chronic disease and elder mistreatment: A meta-analysis

OBJECTIVE

This meta-analysis investigated the relationships between chronic diseases and different forms of elder mistreatment (physical, emotional, sexual, financial, neglect, or overall abuse).

METHOD

Twelve different chronic disease risk markers linked to elder mistreatment were gathered from 48 studies (yielding 178 effect sizes (ESs) and a combined sample size of n = 390,785), then organized in to four broad chronic disease categories: endocrine disease, heart disease, neurological disease, and other chronic diseases. Data were analyzed with Comprehensive Meta-Analysis Software using a random effects approach.

RESULTS

Neurological disease (odds ratio [OR] = 1.51), endocrine disease (OR = 1.38), heart disease (OR = 1.17), and other chronic diseases (OR = 1.26) were all significantly associated with elder mistreatments. Neurological disease (OR = 1.51) was found to have a significantly stronger association with elder mistreatment when compared to the heart disease category (OR = 1.17) and the other chronic disease category (OR = 1.26). When specifically investigating emotional abuse, there was a significantly stronger link with neurological disease (OR = 1.48) compared to other chronic diseases (OR = 1.21).

CONCLUSIONS

This study provides the first meta-analytic benchmarks for understanding the links between chronic disease risk markers and different forms of elder mistreatment.

Key Mechanisms and Potential Implications of Hericium erinaceus in NLRP3 Inflammasome Activation by Reactive Oxygen Species during Alzheimer's Disease

Alzheimer’s disease (AD) is the principal cause of dementia, and its incidence increases with age. Altered antioxidant systems and inflammation have an important role in the etiology of neurodegenerative disorders. In this study, we evaluated the effects of Hericium erinaceus, a nutritional mushroom with important antioxidant effects, in a rat model of AD. Animals were injected with 70 mg/Kg of AlCl3 daily for 6 weeks, and Hericium erinaceus was administered daily by gavage. Before the experiment’s end date, behavioral test training was performed. At the end of the study, behavioral changes were assessed, and the animals were euthanized. Brain tissues were harvested for further analysis. AlCl3 mainly accumulates in the hippocampus, the principal region of the brain involved in memory functions and learning. Hericium erinaceus administration reduced behavioral changes and hippocampal neuronal degeneration. Additionally, it reduced phosphorylated Tau levels, aberrant APP overexpression, and β-amyloid accumulation. Moreover, Hericium erinaceus decreased the pro-oxidative and pro-inflammatory hippocampal alterations induced by AD. In particular, it reduced the activation of the NLRP3 inflammasome components, usually activated by increased oxidative stress during AD. Collectively, our results showed that Hericium erinaceus has protective effects on behavioral alteration and histological modification associated with AD due to the modulation of the oxidative and inflammatory pathways, as well as regulating cellular brain stress.

YAP prevents premature senescence of astrocytes and cognitive decline of Alzheimer's disease through regulating CDK6 signaling

Senescent astrocytes accumulate with aging and contribute to brain dysfunction and diseases such as Alzheimer's disease (AD), however, the mechanisms underlying the senescence of astrocytes during aging remain unclear. In the present study, we found that Yes‐associated Protein (YAP) was downregulated and inactivated in hippocampal astrocytes of aging mice and AD model mice, as well as in D‐galactose and paraquat‐induced senescent astrocytes, in a Hippo pathway‐dependent manner. Conditional knockout of YAP in astrocytes significantly promoted premature senescence of astrocytes, including reduction of cell proliferation, hypertrophic morphology, increase in senescence‐associated β‐galactosidase activity, and upregulation of several senescence‐associated genes such as p16, p53 and NF‐κB, and downregulation of Lamin B1. Further exploration of the underlying mechanism revealed that the expression of cyclin‐dependent kinase 6 (CDK6) was decreased in YAP knockout astrocytes in vivo and in vitro, and ectopic overexpression of CDK6 partially rescued YAP knockout‐induced senescence of astrocytes. Finally, activation of YAP signaling by XMU‐MP‐1 (an inhibitor of Hippo kinase MST1/2) partially rescued the senescence of astrocytes and improved the cognitive function of AD model mice and aging mice. Taken together, our studies identified unrecognized functions of YAP‐CDK6 pathway in preventing astrocytic senescence in vitro and in vivo, which may provide further insights and new targets for delaying brain aging and aging‐related neurodegenerative diseases such as AD.

Targeting autophagy in neurodegenerative diseases: From molecular mechanisms to clinical therapeutics

Many neurodegenerative diseases are associated with pathological aggregation of proteins in neurons. Autophagy is a natural self-cannibalization process that can act as a powerful mechanism to remove aged and damaged organelles as well as protein aggregates. It has been shown that promoting autophagy can attenuate or delay neurodegeneration by removing protein aggregates. In this paper, we will review the role of autophagy in Alzheimer's disease (AD), Parkinson's Disease (PD), and Huntington's Disease (HD) and discuss opportunities and challenges of targeting autophagy as a potential therapeutic avenue for treatment of these common neurodegenerative diseases.

11C-PIB and 124I-antibody PET provide differing estimates of brain amyloid-beta after therapeutic intervention

PET imaging of amyloid-β (Aβ) has become an important component of Alzheimer disease diagnosis. ¹¹C-Pittsburgh compound B (¹¹C-PiB) and analogs bind to fibrillar Aβ. However, levels of nonfibrillar, soluble, aggregates of Aβ appear more dynamic during disease progression and more affected by Aβ-reducing treatments. The aim of this study was to compare an antibody-based PET ligand targeting nonfibrillar Aβ with ¹¹C-PiB after β-secretase (BACE-1) inhibition in 2 Alzheimer disease mouse models at an advanced stage of Aβ pathology. Methods: Transgenic ArcSwe mice (16 mo old) were treated with the BACE-1 inhibitor NB-360 for 2 mo, whereas another group was kept as controls. A third group was analyzed at the age of 16 mo as a baseline. Mice were PET-scanned with ¹¹C-PiB to measure Aβ plaque load followed by a scan with the bispecific radioligand ¹²⁴I-RmAb158-scFv8D3 to investigate nonfibrillar aggregates of Aβ. The same study design was then applied to another mouse model, App^NL-G-F. In this case, NB-360 treatment was initiated at the age of 8 mo and animals were scanned with ¹¹C-PiB-PET and ¹²⁵I-RmAb158-scFv8D3 SPECT. Brain tissue was isolated after scanning, and Aβ levels were assessed. Results:¹²⁴I-RmAb158-scFv8D3 concentrations measured with PET in hippocampus and thalamus of NB-360–treated ArcSwe mice were similar to those observed in baseline animals and significantly lower than concentrations observed in same-age untreated controls. Reduced ¹²⁵I-RmAb158-scFv8D3 retention was also observed with SPECT in hippocampus, cortex, and cerebellum of NB-360–treated App^NL-G-F mice. Radioligand in vivo concentrations corresponded to postmortem brain tissue analysis of soluble Aβ aggregates. For both models, mice treated with NB-360 did not display a reduced ¹¹C-PiB signal compared with untreated controls, and further, both NB-360 and control mice tended, although not reaching significance, to show higher ¹¹C-PiB signal than the baseline groups. Conclusion: This study demonstrated the ability of an antibody-based radioligand to detect changes in brain Aβ levels after anti-Aβ therapy in ArcSwe and App^NL-G-F mice with pronounced Aβ pathology. In contrast, the decreased Aβ levels could not be quantified with ¹¹C-PiB PET, suggesting that these ligands detect different pools of Aβ.

Multi-scale modeling for systematically understanding the key roles of microglia in AD development

Alzheimer's disease (AD) is the leading cause of age-related dementia, affecting over 5 million people in the United States. Unfortunately, current therapies are largely palliative and several potential drug candidates have failed in late-stage clinical trials. Studies suggest that microglia-mediated neuroinflammation might be responsible for the failures of various therapies. Microglia contribute to Aβ clearance in the early stage of neurodegeneration and may contribute to AD development at the late stage by releasing pro-inflammatory cytokines. However, the activation profile and phenotypic changes of microglia during the development of AD are poorly understood. To systematically understand the key role of microglia in AD progression and predict the optimal therapeutic strategy in silico, we developed a 3D multi-scale model of AD (MSMAD) by integrating multi-level experimental data, to manipulate the neurodegeneration in a simulated system. Based on our analysis, we revealed that how TREM2-related signal transduction leads to an imbalance in the activation of different microglia phenotypes, thereby promoting AD development. Our MSMAD model also provides an optimal therapeutic strategy for improving the outcome of AD treatment.

Roles and Mechanisms of Gut Microbiota in Patients With Alzheimer's Disease

Alzheimer’s disease (AD) is the most common age-related progressive neurodegenerative disease, characterized by a decline in cognitive function and neuronal loss, and is caused by several factors. Numerous clinical and experimental studies have suggested the involvement of gut microbiota dysbiosis in patients with AD. The altered gut microbiota can influence brain function and behavior through the microbiota–gut–brain axis via various pathways such as increased amyloid-β deposits and tau phosphorylation, neuroinflammation, metabolic dysfunctions, and chronic oxidative stress. With no current effective therapy to cure AD, gut microbiota modulation may be a promising therapeutic option to prevent or delay the onset of AD or counteract its progression. Our present review summarizes the alterations in the gut microbiota in patients with AD, the pathogenetic roles and mechanisms of gut microbiota in AD, and gut microbiota–targeted therapies for AD. Understanding the roles and mechanisms between gut microbiota and AD will help decipher the pathogenesis of AD from novel perspectives and shed light on novel therapeutic strategies for AD.

An automated radiosynthesis of (S)-[18F]28 for PET imaging of Alzheimer's disease

¹⁸F-labeled 2-arylbenzoxazole derivative (S)-[¹⁸F]28 is potent and selective radiopharmaceutical Aβ tracers for Alzheimer's disease positron-emission tomography (PET). Our study aimed to enable facile preparation of (S)-[¹⁸F]28 in commercially available PET tracer production facilities to promote the widespread application and clinical translation. Here, we successfully demonstrated an automated radiosynthesis of (S)-[¹⁸F]28 with high radiochemical yield and radiochemical purity by the AllinOne radiosynthesis module. The method developed here can facilitate extensive use of (S)-[¹⁸F]28 in large-scale clinical trials.

Microglial activation in the right amygdala-entorhinal-hippocampal complex is associated with preserved spatial learning in AppNL-G-F mice

BACKGROUND

In Alzheimer`s disease (AD), regional heterogeneity of β-amyloid burden and microglial activation of individual patients is a well-known phenomenon. Recently, we described a high incidence of inter-individual regional heterogeneity in terms of asymmetry of plaque burden and microglial activation in β-amyloid mouse models of AD as assessed by positron-emission-tomography (PET). We now investigate the regional associations between amyloid plaque burden, microglial activation, and impaired spatial learning performance in transgenic mice in vivo.

METHODS

In 30 App^NL-G-F mice (15 female, 15 male) we acquired cross-sectional 18 kDa translocator protein (TSPO-PET, ¹⁸F-GE-180) and β-amyloid-PET (¹⁸F-florbetaben) scans at ten months of age. Control data were obtained from age- and sex-matched C57BI/6 wild-type mice. We assessed spatial learning (i.e. Morris water maze) within two weeks of PET scanning and correlated the principal component of spatial learning performance scores with voxel-wise β-amyloid and TSPO tracer uptake maps in App^NL-G-F mice, controlled for age and sex. In order to assess the effects of hemispheric asymmetry, we also analyzed correlations of spatial learning performance with tracer uptake in bilateral regions of interest for frontal cortex, entorhinal/piriform cortex, amygdala, and hippocampus, using a regression model. We tested the correlation between regional asymmetry of PET biomarkers with individual spatial learning performance.

RESULTS

Voxel-wise analyses in App^NL-G-F mice revealed that higher TSPO-PET signal in the amygdala, entorhinal and piriform cortices, the hippocampus and the hypothalamus correlated with spatial learning performance. Region-based analysis showed significant correlations between TSPO expression in the right entorhinal/piriform cortex and the right amygdala and spatial learning performance, whereas there were no such correlations in the left hemisphere. Right lateralized TSPO expression in the amygdala predicted better performance in the Morris water maze (β = -0.470, p = 0.013), irrespective of the global microglial activation and amyloid level. Region-based results for amyloid-PET showed no significant associations with spatial learning.

CONCLUSION

Elevated microglial activation in the right amygdala-entorhinal-hippocampal complex of App^NL-G-F mice is associated with better spatial learning. Our findings support a protective role of microglia on cognitive function when they highly express TSPO in specific brain regions involved in spatial memory.

Glial activation is moderated by sex in response to amyloidosis but not to tau pathology in mouse models of neurodegenerative diseases

Background

In vivo assessment of neuroinflammation by 18-kDa translocator protein positron-emission-tomography (TSPO-PET) ligands receives growing interest in preclinical and clinical research of neurodegenerative disorders. Higher TSPO-PET binding as a surrogate for microglial activation in females has been reported for cognitively normal humans, but such effects have not yet been evaluated in rodent models of neurodegeneration and their controls. Thus, we aimed to investigate the impact of sex on microglial activation in amyloid and tau mouse models and wild-type controls.

Methods

TSPO-PET (¹⁸F-GE-180) data of C57Bl/6 (wild-type), App^NL-G-F (β-amyloid model), and P301S (tau model) mice was assessed longitudinally between 2 and 12 months of age. The App^NL-G-F group also underwent longitudinal β-amyloid-PET imaging (Aβ-PET; ¹⁸F-florbetaben). PET results were confirmed and validated by immunohistochemical investigation of microglial (Iba-1, CD68), astrocytic (GFAP), and tau (AT8) markers. Findings in cerebral cortex were compared by sex using linear mixed models for PET data and analysis of variance for immunohistochemistry.

Results

Wild-type mice showed an increased TSPO-PET signal over time (female +23%, male +4%), with a significant sex × age interaction (T = − 4.171, p < 0.001). The Aβ model App^NL-G-F mice also showed a significant sex × age interaction (T = − 2.953, p = 0.0048), where cortical TSPO-PET values increased by 31% in female App^NL-G-F mice, versus only 6% in the male mice group from 2.5 to 10 months of age. Immunohistochemistry for the microglial markers Iba-1 and CD68 confirmed the TSPO-PET findings in male and female mice aged 10 months. Aβ-PET in the same App^NL-G-F mice indicated no significant sex × age interaction (T = 0.425, p = 0.673). The P301S tau model showed strong cortical increases of TSPO-PET from 2 to 8.5 months of age (female + 32%, male + 36%), without any significant sex × age interaction (T = − 0.671, p = 0.504), and no sex differences in Iba-1, CD68, or AT8 immunohistochemistry.

Conclusion

Female mice indicate sex-dependent microglia activation in aging and in response to amyloidosis but not in response to tau pathology. This calls for consideration of sex difference in TSPO-PET studies of microglial activation in mouse models of neurodegeneration and by extension in human studies.

Inpatient diagnoses of idiopathic normal pressure hydrocephalus in the United States: Demographic and socioeconomic disparities

INTRODUCTION

Epidemiology provides an avenue for identifying disease pathogenesis, hence determining national incidence, along with socioeconomic and demographic variables involved in iNPH, can provide direction in elucidating the etiology and addressing healthcare inequalities.

METHODS

To investigate incidence (per 100,000) of iNPH diagnoses applied to the inpatient population, with respect to sex, age, income, residence, and race/ethnicity, we queried the largest American administrative dataset (2008-2016), the National (Nationwide) Inpatient Sample (NIS), which surveys 20% of United States (US) discharges.

RESULTS

Annual national inpatient incidence (with 25th and 75th quartiles) for iNPH diagnoses was 2.86 (2.72, 2.93). Males had an inpatient incidence of 3.27 (3.11, 3.39), higher (p = 0.008) than female at 2.45 (2.41, 2.47). Amongst age groups inpatient incidence varied (p = 0.000004) and was largest amongst the 85+ group at 18.81 (16.40, 19.95). Individuals with middle/high income had an inpatient incidence of 2.96 (2.77, 3.06), higher (p = 0.008) than the 2.37 (2.24, 2.53) of low-income patients. Depending on whether patients lived in urban, suburban, or rural communities, inpatient incidence diverged (p = 0.01) as follows, respectively: 2.65; 2.66; 3.036. Amongst race/ethnicity (p = 0.000003), inpatient incidence for Whites, Blacks, Hispanics, Asian/Pacific Islanders, and Native Americans were as follows, respectively: 3.88 (3.69, 3.93), 1.065 (1.015, 1.14); 0.82 (0.76, 0.85); 0.43 (0.33, 0.52); 0.027 (0.026, 0.12).

CONCLUSION

In the US, inpatient incidence for iNPH diagnoses exhibited disparities between socioeconomic and demographic strata, emphasizing a healthcare inequality. Disproportionately, diagnoses were applied most to patients who were White, male, 65 and older, middle/high income, and living in rural communities.

Fusion of ULS Group Constrained High- and Low-Order Sparse Functional Connectivity Networks for MCI Classification

Functional connectivity networks, derived from resting-state fMRI data, have been found as effective biomarkers for identifying mild cognitive impairment (MCI) from healthy elderly. However, the traditional functional connectivity network is essentially a low-order network with the assumption that the brain activity is static over the entire scanning period, ignoring temporal variations among the correlations derived from brain region pairs. To overcome this limitation, we proposed a new type of sparse functional connectivity network to precisely describe the relationship of temporal correlations among brain regions. Specifically, instead of using the simple pairwise Pearson's correlation coefficient as connectivity, we first estimate the temporal low-order functional connectivity for each region pair based on an ULS Group constrained-UOLS regression algorithm, where a combination of ultra-least squares (ULS) criterion with a Group constrained topology structure detection algorithm is applied to detect the topology of functional connectivity networks, aided by an Ultra-Orthogonal Least Squares (UOLS) algorithm to estimate connectivity strength. Compared to the classical least squares criterion which only measures the discrepancy between the observed signals and the model prediction function, the ULS criterion takes into consideration the discrepancy between the weak derivatives of the observed signals and the model prediction function and thus avoids the overfitting problem. By using a similar approach, we then estimate the high-order functional connectivity from the low-order connectivity to characterize signal flows among the brain regions. We finally fuse the low-order and the high-order networks using two decision trees for MCI classification. Experimental results demonstrate the effectiveness of the proposed method on MCI classification.

Generating national projections of dementia cases for Ireland using a calibrated macro-simulation model

INTRODUCTION

Epidemiological data on dementia is not available in many European countries and regions due to the high cost and complexity of conducting large scale dementia screening studies. The available epidemiological studies identify potentially substantial variation in the prevalence of dementia over time and across Europe.

METHODS

In this paper we generate simulations of the number of dementia cases in Ireland from 1991 to 2036 using a three-state Markov illness-death model. Parameters values are selected for each simulation from a range using a random parameter search pattern. We employ a novel calibration method which exploits the strong relationship between dementia, ageing and mortality. Simulation weights are generated based on differences between observed and modelled cohorts of older people and the reported number of deaths from dementia. Irish Census data from 1991 to 2016 and the number of recorded deaths due to dementia in 2018 are used as calibration points. A weighted average projection of the number of dementia cases is generated.

RESULTS

We estimate a weighted average number of cases of dementia in 2016 of 54 877 increasing to 98 946 in 2036; this estimate is substantially lower than the estimates generated using extrapolation methods. We show the wide range of possible outcomes given the range in the available parameter estimates and show that irrespective of whether the incidence rate of dementia is declining the number of cases of dementia is rapidly increasing due to population ageing.

CONCLUSION

Previous studies have used parameter estimates from meta-analyses of the literature or from individual studies. In this paper we supplement these with a calibration approach using observed cause of death and population age structure data. These additional sources of data can be used to generate estimates of dementia prevalence in any country or region which has census data and data on deaths due to dementia.

Characterization of 18F-PM-PBB3 (18F-APN-1607) Uptake in the rTg4510 Mouse Model of Tauopathy

Misfolding, aggregation, and cerebral accumulation of tau deposits are hallmark features of Alzheimer’s disease. Positron emission tomography study of tau can facilitate the development of anti-tau treatment. Here, we investigated a novel tau tracer ¹⁸F-PM-PBB3 (¹⁸F-APN-1607) in a mouse model of tauopathy. Dynamic PET scans were collected in groups of rTg4510 transgenic mice at 2–11 months of age. Associations between distribution volume ratios (DVR) and standardized uptake value ratios (SUVR) with cerebellum reference were used to determine the optimal scanning time and uptake pattern for each age. Immunohistochemistry staining of neurofibrillary tangles and autoradiography study was performed for ex vivo validation. An SUVR 40–70 min was most consistently correlated with DVR and was used in further analyses. Significant increased ¹⁸F-PM-PBB3 uptake in the brain cortex was found in six-month-old mice (+28.9%, p < 0.05), and increased further in the nine-month-old group (+38.8%, p < 0.01). The trend of increased SUVR value remained evident in the hippocampus and striatum regions except for cortex where uptake becomes slightly reduced in 11-month-old animals (+37.3%, p < 0.05). Radioactivity distributions from autoradiography correlate well to the presence of human tau (HT7 antibody) and hyperphosphorylated tau (antibody AT8) from the immunohistochemistry study of the adjacent brain sections. These findings supported that the 40–70 min ¹⁸F-PM-PBB3 PET scan with SUVR measurement can detect significantly increased tau deposits in a living rTg4510 transgenic mouse models as early as six-months-old. The result exhibited promising dynamic imaging capability of this novel tau tracer, and the above image characteristics should be considered in the design of longitudinal preclinical tau image studies.

Effects of lycopene on vascular remodeling through the LXR-PI3K-AKT signaling pathway in APP/PS1 mice

Alzheimer's disease (AD) is the commonest neurodegenerative disease and, in recent years, studies have increasingly shown that vascular lesions are involved in the pathology of AD onset and progression. Many vascular changes precede the pathological changes and clinical symptoms of AD, and vascular lesions and AD have many common risk factors. Understanding the relationship between vascular factors and the pathological process of AD may help us to identify novel prevention and treatment strategies as well as delay disease progress. Previous studies have shown that lycopene has neuroprotective, antioxidant, and anticancer effects; however, the specific molecular mechanism mediating these effects remains unknown. In the present study, we found: 1) lycopene improved learning and memory in an AD mouse model; 2) lycopene inhibited amyloid plaque aggregation and neuroinflammation; and 3) lycopene induced LXR expression and activated the LXR-PI3K-AKT signaling pathway. Our findings suggest that promotion of neurogenesis and improvement of the functions of the neurovascular unit could be a novel direction for the development of AD therapies.

[18F]-florbetaben PET/CT Imaging in the Alzheimer's Disease Mouse Model APPswe/PS1dE9

BACKGROUND

Positron-emission-tomography (PET) using 18F labeled florbetaben allows noninvasive in vivo-assessment of amyloid-beta (Aβ), a pathological hallmark of Alzheimer's disease (AD). In preclinical research, [¹⁸F]-florbetaben-PET has already been used to test the amyloid-lowering potential of new drugs, both in humans and in transgenic models of cerebral amyloidosis. The aim of this study was to characterize the spatial pattern of cerebral uptake of [¹⁸F]-florbetaben in the APPswe/ PS1dE9 mouse model of AD in comparison to histologically determined number and size of cerebral Aβ plaques.

METHODS

Both, APPswe/PS1dE9 and wild type mice at an age of 12 months were investigated by smallanimal PET/CT after intravenous injection of [¹⁸F]-florbetaben. High-resolution magnetic resonance imaging data were used for quantification of the PET data by volume of interest analysis. The standardized uptake values (SUVs) of [¹⁸F]-florbetaben in vivo as well as post mortem cerebral Aβ plaque load in cortex, hippocampus and cerebellum were analyzed.

RESULTS

Visual inspection and SUVs revealed an increased cerebral uptake of [¹⁸F]-florbetaben in APPswe/ PS1dE9 mice compared with wild type mice especially in the cortex, the hippocampus and the cerebellum. However, SUV ratios (SUVRs) relative to cerebellum revealed only significant differences in the hippocampus between the APPswe/PS1dE9 and wild type mice but not in cortex; this differential effect may reflect the lower plaque area in the cortex than in the hippocampus as found in the histological analysis.

CONCLUSION

The findings suggest that histopathological characteristics of Aβ plaque size and spatial distribution can be depicted in vivo using [¹⁸F]-florbetaben in the APPswe/PS1dE9 mouse model.

Post-sepsis syndrome - an evolving entity that afflicts survivors of sepsis

BACKGROUND

The sequelae of sepsis were once thought to be independent of sepsis itself and assumed to be either comorbid to sick patients or complications of critical illness. Recent studies have reported consistent patterns of functional disabilities in sepsis survivors that can last from months to years after symptoms of active sepsis had resolved. BODY: Post-sepsis syndrome is an emerging pathological entity that has garnered significant interest amongst clinicians and researchers over the last two decades. It is marked by a significantly increased risk of death and a poor health-related quality of life associated with a constellation of long-term effects that persist following the patient's bout with sepsis. These include neurocognitive impairment, functional disability, psychological deficits, and worsening medical conditions.

CONCLUSION

This "post-sepsis syndrome" has been the subject of active preclinical and clinical research providing new mechanistic insights and approaches linked to survivor well-being. Here we review important aspects of these research efforts and goals of care for patients who survive sepsis.

Estimates of the prevalence, incidence and severity of dementia in Ireland

OBJECTIVES

In this paper we provide revised estimates of the prevalence of dementia in Ireland, the number of new cases per year and the severity mix. These estimates are a necessary input for any assessment of the potential demand for services and supports for people with dementia across all care settings in Ireland.

METHODS

The prevalence, incidence and severity stage of dementia are calculated by applying rates from prominent international studies to population data from the 2016 census.

RESULTS

We show that the total number of people with dementia in Ireland ranges between 39 272 and 55 266, depending on the international rates used to measure prevalence. The incidence of dementia in Ireland has increased as the population has aged, to at least 7752 new cases per year. We estimate that there are at least 11 175 people living at home in the community in Ireland with dementia who have a serious functional impairment, based on an Activities of Daily Living measurement, of which an estimated 1876 are chair or bedbound.

CONCLUSIONS

Without a national prevalence study it is not possible to be precise about the estimates of the number of people with dementia in Ireland. However, having credible upper and lower bound estimates for the number of people with dementia, the potential number of new cases per year and severity rates is useful for planners and those charged with the responsibility of making resource allocation decisions in dementia.

Age-Dependent Relationship Between Plasma Aβ40 and Aβ42 and Total Tau Levels in Cognitively Normal Subjects

Both amyloid plaques and neurofibrillary tangles are pathological hallmarks in the brains of patients with Alzheimer’s disease (AD). However, the constituents of these hallmarks, amyloid beta (Aβ) 40, Aβ42, and total Tau (t-Tau), have been detected in the blood of cognitively normal subjects by using an immunomagnetic reduction (IMR) assay. Whether these levels are age-dependent is not known, and their interrelation remains undefined. We determined the levels of these biomarkers in cognitively normal subjects of different age groups. A total of 391 cognitively normal subjects aged 23–91 were enrolled from hospitals in Asia, Europe, and North America. Healthy cognition was evaluated by NIA-AA guidelines to exclude subjects with mild cognitive impairment (MCI) and AD and by cognitive assessment using the Mini Mental State Examination and Clinical Dementia Rating (CDR). We examined the effect of age on plasma levels of Aβ40, Aβ42, and t-Tau and the relationship between these biomarkers during aging. Additionally, we explored age-related reference intervals for each biomarker. Plasma t-Tau and Aβ42 levels had modest but significant correlations with chronological age (r = 0.127, p = 0.0120 for t-Tau; r = −0.126, p = 0.0128 for Aβ42), ranging from ages 23 to 91. Significant positive correlations were detected between Aβ42 and t-Tau in the groups aged 50 years and older, with Rho values ranging from 0.249 to 0.474. Significant negative correlations were detected between Aβ40 and t-Tau from age 40 to 91 (r ranged from −0.293 to −0.582) and between Aβ40 and Aβ42 in the age groups of 30–39 (r = −0.562, p = 0.0235), 50–59 (r = −0.261, p = 0.0142), 60–69 (r = −0.303, p = 0.0004), and 80–91 (r = 0.459, p = 0.0083). We also provided age-related reference intervals for each biomarker. In this multicenter study, age had weak but significant effects on the levels of Aβ42 and t-Tau in plasma. However, the age group defined by decade revealed the emergence of a relationship between Aβ40, Aβ42, and t-Tau in the 6th and 7th decades. Validation of our findings in a large-scale and longitudinal study is warranted.

Neuronal injury biomarkers for assessment of the individual cognitive reserve in clinically suspected Alzheimer's disease

OBJECTIVES

Many predictive or influencing factors have emerged in investigations of the cognitive reserve model of patients with Alzheimer's disease (AD). For example, neuronal injury, which correlates with cognitive decline in AD, can be assessed by [¹⁸F]-fluorodeoxyglucose positron-emission-tomography (FDG-PET), structural magnetic resonance imaging (MRI) and total tau in cerebrospinal fluid (CSF_t-tau), all according to the A/T/N-classification. The aim of this study was to calculate residual cognitive performance based on neuronal injury biomarkers as a surrogate of cognitive reserve, and to test the predictive value of this index for the individual clinical course.

METHODS

110 initially mild cognitive impaired and demented subjects (age 71 ± 8 years) with a final diagnosis of AD dementia were assessed at baseline by clinical mini-mental-state-examination (MMSE), FDG-PET, MRI and CSF_t-tau. All neuronal injury markers were tested for an association with clinical MMSE and the resulting residuals were correlated with years of education. We used multiple regression analysis to calculate the expected MMSE score based on neuronal injury biomarkers and covariates. The residuals of the partial correlation for each biomarker and the predicted residualized memory function were correlated with individual cognitive changes measured during clinical follow-up (27 ± 13 months).

RESULTS

FDG-PET correlated highly with clinical MMSE (R = -0.49, p < .01), whereas hippocampal atrophy to MRI (R = -0.15, p = .14) and CSF_t-tau (R = -0.12, p = .22) showed only weak correlations. Residuals of all neuronal injury biomarker regressions correlated significantly with education level, indicating them to be surrogates of cognitive reserve. A positive residual was associated with faster cognitive deterioration at follow-up for the residuals of stand-alone FDG-PET (R = -0.36, p = .01) and the combined residualized memory function model (R = -0.35, p = .02).

CONCLUSIONS

These findings suggest that subjects with higher cognitive reserve had accumulated more pathology, which subsequently caused a faster cognitive decline over time. Together with previous findings suggesting that higher reserve is associated with slower cognitive decline, we propose a biphasic reserve effect, with an initially protective phase followed by more rapid decompensation once the protection is overwhelmed.

Longitudinal PET Monitoring of Amyloidosis and Microglial Activation in a Second-Generation Amyloid-β Mouse Model

Nonphysiologic overexpression of amyloid-β (Aβ) precursor protein in common transgenic Aβ mouse models of Alzheimer disease likely hampers their translational potential. The novel App ^NL-G-F mouse incorporates a mutated knock-in, potentially presenting an improved model of Alzheimer disease for Aβ-targeting treatment trials. We aimed to establish serial small-animal PET of amyloidosis and neuroinflammation in App ^NL-G-F mice as a tool for therapy monitoring. Methods: App ^NL-G-F mice (20 homozygous and 21 heterogeneous) and 12 age-matched wild-type mice were investigated longitudinally from 2.5 to 10 mo of age with ¹⁸F-florbetaben Aβ PET and ¹⁸F-GE-180 18-kDa translocator protein (TSPO) PET. Voxelwise analysis of SUV ratio images was performed using statistical parametric mapping. All mice underwent a Morris water maze test of spatial learning after their final scan. Quantification of fibrillar Aβ and activated microglia by immunohistochemistry and biochemistry served for validation of the PET results. Results: The periaqueductal gray emerged as a suitable pseudo reference tissue for both tracers. Homozygous App ^NL-G-F mice had a rising SUV ratio in cortex and hippocampus for Aβ (+9.1%, +3.8%) and TSPO (+19.8%, +14.2%) PET from 2.5 to 10 mo of age (all P < 0.05), whereas heterozygous App ^NL-G-F mice did not show significant changes with age. Significant voxelwise clusters of Aβ deposition and microglial activation in homozygous mice appeared at 5 mo of age. Immunohistochemical and biochemical findings correlated strongly with the PET data. Water maze escape latency was significantly elevated in homozygous App ^NL-G-F mice compared with wild-type at 10 mo of age and was associated with high TSPO binding. Conclusion: Longitudinal PET in App ^NL-G-F knock-in mice enables monitoring of amyloidogenesis and neuroinflammation in homozygous mice but is insensitive to minor changes in heterozygous animals. The combination of PET with behavioral tasks in App ^NL-G-F treatment trials is poised to provide important insights in preclinical drug development.

Identification of 12 genetic loci associated with human healthspan

Aging populations face diminishing quality of life due to increased disease and morbidity. These challenges call for longevity research to focus on understanding the pathways controlling healthspan. We use the data from the UK Biobank (UKB) cohort and observe that the risks of major chronic diseases increased exponentially and double every eight years, i.e., at a rate compatible with the Gompertz mortality law. Assuming that aging drives the acceleration in morbidity rates, we build a risk model to predict the age at the end of healthspan depending on age, gender, and genetic background. Using the sub-population of 300,447 British individuals as a discovery cohort, we identify 12 loci associated with healthspan at the whole-genome significance level. We find strong genetic correlations between healthspan and all-cause mortality, life-history, and lifestyle traits. We thereby conclude that the healthspan offers a promising new way to interrogate the genetics of human longevity.

The role of membrane trafficking in the processing of amyloid precursor protein and production of amyloid peptides in Alzheimer's disease

Alzheimer's disease (AD) is characterized by progressive accumulation of misfolded proteins, which form senile plaques and neurofibrillary tangles, and the release of inflammatory mediators by innate immune responses. β-Amyloid peptide (Aβ) is derived from sequential processing of the amyloid precursor protein (APP) by membrane-bound proteases, namely the β-secretase, BACE1, and γ-secretase. Membrane trafficking plays a key role in the regulation of APP processing as both APP and the processing secretases traffic along distinct pathways. Genome wide sequencing studies have identified several AD susceptibility genes which regulate membrane trafficking events. To understand the pathogenesis of AD it is critical that the cell biology of APP and Aβ production in neurons is well defined. This review discusses recent advances in unravelling the membrane trafficking events associated with the production of Aβ, and how AD susceptible alleles may perturb the sorting and transport of APP and BACE1. Mechanisms whereby inflammation may influence APP processing are also considered.

Comparative Epidemiological Investigation of Alzheimer's Disease and Colorectal Cancer: The Possible Role of Gastrointestinal Conditions in the Pathogenesis of AD

Alzheimer's disease (AD) is a neurodegenerative disorder that affects approximately 35 million people worldwide, and diet has been reported to influence the prevalence/incidence of AD. Colorectal cancer is among the most common cancers in Western populations, and the correlation between constipation and the occurrence of colorectal cancer has been identified in a number of studies, which show that a Westernized diet is a mutual risk factor. Constipation is a growing health problem, particularly in middle-aged and older adults. As the most common gastrointestinal disorder in adults, constipation affects 2-20% of the world population, and it is associated with several diseases, such as diabetes, Parkinson's disease, and others. Comparing the epidemiological data on colorectal cancer and AD, we find that colorectal cancer and AD have similar epidemiologic feature, which is both disease correlate with high prevalence of constipation. Therefore, we hypothesized that constipation may influence Alzheimer's disease in a similar way that it contributes to colorectal cancer. This review aimed to systemically elucidate the evidence that constipation contributes to Alzheimer's disease progression.

Efficacy of chronic BACE1 inhibition in PS2APP mice depends on the regional Aβ deposition rate and plaque burden at treatment initiation

Beta secretase (BACE) inhibitors are promising therapeutic compounds currently in clinical phase II/III trials. Preclinical [18F]-florbetaben (FBB) amyloid PET imaging facilitates longitudinal monitoring of amyloidosis in Alzheimer's disease (AD) mouse models. Therefore, we applied this theranostic concept to investigate, by serial FBB PET, the efficacy of a novel BACE1 inhibitor in the PS2APP mouse, which is characterized by early and massive amyloid deposition. Methods: PS2APP and C57BL/6 (WT) mice were assigned to treatment (PS2APP: N=13; WT: N=11) and vehicle control (PS2APP: N=13; WT: N=11) groups at the age of 9.5 months. All animals had a baseline PET scan and follow-up scans at two months and after completion of the four-month treatment period. In addition to this longitudinal analysis of cerebral amyloidosis by PET, we undertook biochemical amyloid peptide quantification and histological amyloid plaque analyses after the final PET session. Results: BACE1 inhibitor-treated transgenic mice revealed a progression of the frontal cortical amyloid signal by 8.4 ± 2.2% during the whole treatment period, which was distinctly lower when compared to vehicle-treated mice (15.3 ± 4.4%, p<0.001). A full inhibition of progression was evident in regions with <3.7% of the increase in controls, whereas regions with >10% of the increase in controls showed only 40% attenuation with BACE1 inhibition. BACE1 inhibition in mice with lower amyloidosis at treatment initiation showed a higher efficacy in attenuating progression to PET. A predominant reduction of small plaques in treated mice indicated a main effect of BACE1 on inhibition of de novo amyloidogenesis. Conclusions: This theranostic study with BACE1 treatment in a transgenic AD model together with amyloid PET monitoring indicated that progression of amyloidosis is more effectively reduced in regions with low initial plaque development and revealed the need of an early treatment initiation during amyloidogenesis.

Development and validation of Cognitive Training Intervention for Alzheimer's disease (CTI-AD): A picture-based interventional program

Introduction

Alzheimer’s disease is a gradual and progressive disorder which cripples the person’s functionality due to cognitive decline. Many clinicopathological and pharmacological therapy has the potential to slow down the progression of the disease but has limited efficacy. One complimentary approach that has emerged is cognitive training interventions which have shown synergistic effect with the drug therapy. Nevertheless, many cognitive interventions lack on specificities of the intervention due to which its efficacy gets scrutinized.

Objective

To describe the foundation, content, and development of Cognitive Training Intervention for Alzheimer’s disease (CTI-AD) along with the treatment feasibility based on a pilot study.

Materials and methods

A culture-specific picture-based eight weeks cognitive training manual was developed based on extensive review and focused group discussions. It was standardized on 63 older participants (48 healthy controls (HC); 15 early Alzheimer’s disease cases).

Results

All the tasks were progressive in nature and were found effective in discriminating the cognitive performance of early Alzheimer’s disease and HC throughout the intervention period. Moreover, it also improved early Alzheimer’s disease performance on the memory (HC: 1st week/8th week = 21.6 ± 5.7/57.3 ± 19.0; early Alzheimer’s disease: 1st week/8th week = 48.5 ± 22.9/60.5 ± 21.8); attention (HC: 1st week/8th week = 90.2 ± 18.0/196.9 ± 28.0; early Alzheimer’s disease: 1st week/8th week = 216.6 ± 78.2/286.8 ± 87.0) and language (HC: 1st week/8th week = 29.8 ± 9.4/115.3 ± 31.1; early Alzheimer’s disease: 1st week/8th week = 211.8 ± 68.4/270.4 ± 104.9) domains, respectively, from the baseline level.

Conclusion

The current manual (CTI-AD) is one of the first promising non-pharmacological program developed nationally with a strong theoretical base to cater to the tertiary needs of the older adults with early Alzheimer’s disease.

BACE1 inhibition more effectively suppresses initiation than progression of β-amyloid pathology

BACE1 is the rate-limiting protease in the production of synaptotoxic β-amyloid (Aβ) species and hence one of the prime drug targets for potential therapy of Alzheimer's disease (AD). However, so far pharmacological BACE1 inhibition failed to rescue the cognitive decline in mild-to-moderate AD patients, which indicates that treatment at the symptomatic stage might be too late. In the current study, chronic in vivo two-photon microscopy was performed in a transgenic AD model to monitor the impact of pharmacological BACE1 inhibition on early β-amyloid pathology. The longitudinal approach allowed to assess the kinetics of individual plaques and associated presynaptic pathology, before and throughout treatment. BACE1 inhibition could not halt but slow down progressive β-amyloid deposition and associated synaptic pathology. Notably, the data revealed that the initial process of plaque formation, rather than the subsequent phase of gradual plaque growth, is most sensitive to BACE1 inhibition. This finding of particular susceptibility of plaque formation has profound implications to achieve optimal therapeutic efficacy for the prospective treatment of AD.

Reciprocal Interactions of Mitochondria and the Neuroimmunoendocrine System in Neurodegenerative Disorders: An Important Role for Melatonin Regulation

Structural and functional alterations of mitochondria are intimately linked to a wide array of medical conditions. Many factors are involved in the regulation of mitochondrial function, including cytokines, chaperones, chemokines, neurosteroids, and ubiquitins. The role of diffusely located cells of the neuroendocrine system, including biogenic amines and peptide hormones, in the management of mitochondrial function, as well as the role of altered mitochondrial function in the regulation of these cells and system, is an area of intense investigation. The current article looks at the interactions among the cells of the neuronal-glia, immune and endocrine systems, namely the diffuse neuroimmunoendocrine system (DNIES), and how DNIES interacts with mitochondrial function. Whilst changes in DNIES can impact on mitochondrial function, local, and systemic alterations in mitochondrial function can alter the component systems of DNIES and their interactions. This has etiological, course, and treatment implications for a wide range of medical conditions, including neurodegenerative disorders. Available data on the role of melatonin in these interactions, at cellular and system levels, are reviewed, with directions for future research indicated.

Neuroinflammation and neurohormesis in the pathogenesis of Alzheimer's disease and Alzheimer-linked pathologies: modulation by nutritional mushrooms

Human life develops and expands not only in time and space, but also in the retrograde permanent recollection and interweaving of memories. Therefore, individual human identity depends fully on a proper access to the autobiographical memory. Such access is hindered or lost under pathological conditions such as Alzheimer’s disease, including recently associated oxidant pathologies, such as ocular neural degeneration occurring in glaucoma or neurosensorial degeneration occurring in Menière’s disease. Oxidative stress and altered antioxidant systems have been suggested to play a role in the aetiology of major neurodegenerative disorders, and altered expression of genes sensing oxidative stress, as well as decreased cellular stress response mechanisms could synergistically contribute to the course of these oxidant disorders. Thus, the theory that low levels of stress can produce protective responses against the pathogenic processes is a frontier area of neurobiological research focal to understanding and developing therapeutic approaches to neurodegenerative disorders. Herein, we discuss cellular mechanisms underlying AD neuroinflammatory pathogenesis that are contributory to Alzheimer’s disease. We describe endogenous cellular defence mechanism modulation and neurohormesis as a potentially innovative approach to therapeutics for AD and other neurodegenerative conditions that are associated with mitochondrial dysfunction and neuroinflammation. Particularly, we consider the emerging role of the inflammasome as an important component of the neuroprotective network, as well as the importance of Coriolus and Hericium nutritional mushrooms in redox stress responsive mechanisms and neuroprotection.

Risk of Developing Dementia at Older Ages in the United States

Dementia is increasingly recognized as a major source of disease burden in the United States, yet little research has evaluated the lifecycle implications of dementia. To address this research gap, this article uses the Aging, Demographics, and Memory Study (ADAMS) to provide the first nationally representative, longitudinal estimates of the probability that a dementia-free person will develop dementia later in life. For the 1920 birth cohort, the average dementia-free 70-year-old male had an estimated 26.9 % (SE = 3.2 %) probability of developing dementia, and the average dementia-free 70-year-old female had an estimated 34.7 % (SE = 3.7 %) probability. These estimates of risk of dementia are higher for younger, lower-mortality cohorts and are substantially higher than those found in local epidemiological studies in the United States, suggesting a widespread need to prepare for a life stage with dementia.