Prevalence and incidence of Alzheimer's disease in Europe: A meta-analysis

Rhoifolin, baicalein 5,6-dimethyl ether and agathisflavone prevent amnesia induced in scopolamine zebrafish (Danio rerio) model by increasing the mRNA expression of bdnf, npy, egr-1, nfr2α, and creb1 genes

The increasing attention towards age-related diseases has generated significant interest in the concept of cognitive dysfunction associated with Alzheimer's disease (AD). Certain limitations are associated with the current therapies, and flavonoids have been reported to exhibit multiple biological activities and anti-AD effects in several AD models owing to their antioxidative, anti-inflammatory, and anti-amyloidogenic properties. In this study, we performed an initial in silico predictions of the pharmacokinetic properties of three flavonoids (rhoifolin, baicalein 5,6-dimethyl ether and agathisflavone). Subsequently, we evaluated the antiamnesic and antioxidant potential of flavonoids in concentrations of 1, 3, and 5 μg/L in scopolamine (100 μM)-induced amnesic zebrafish (Danio rerio) model. Zebrafish behavior was analyzed by novel tank diving test (NTT), Y-maze, and novel object recognition test (NOR). Acetylcholinesterase (AChE) activity, brain antioxidant status and the expression of bdnf, npy, egr1, nrf2α, creb1 genes, and CREB-1 protein level was measured to elucidate the underlying mechanism of action. Our flavonoids improved memory and decreased anxiety-like behavior of scopolamine-induced amnesia in zebrafish. Also, the studied flavonoids reduced AChE activity and brain oxidative stress and upregulated the gene expression, collectively contributing to neuroprotective properties. The results of our study add new perspectives on the properties of flavonoids to regulate the evolution of neurodegenerative diseases, especially AD, by modulating the expression of genes involved in the regulation of synaptic plasticity, axonal growth, and guidance, sympathetic and vagal transmission, the antioxidant response and cell proliferation and growth.

Global prevalence of depression, anxiety, and stress in the elderly population: a systematic review and meta-analysis

BACKGROUND

Several preliminary studies have been conducted in the field of the prevalence of depression, anxiety, and stress in the elderly population. These studies have examined the prevalence in limited geographic areas with small sample sizes. Also, there are many limitations in the meta-analysis studies. The objective of the present study was to synthesize the global prevalence statistics of depression, anxiety, and stress in the elderly population through a systematic review and meta-analysis.

METHODS

The present systematic review included retrieval of primary studies from the oldest relevant study up to 2023. To find the relevant studies, international databases such as Scopus, Embase, PubMed, and Web of Science (WoS) were systematically searched. Also, a manual search was performed through the Google Scholar search engine and a review of the sources of related articles. The qualitative assessment of the studies was conducted using the Joanna Briggs Institute (JBI) checklist. Due to a high heterogeneity among the study results, a Random Effects model was chosen.

RESULTS

A total of 42 articles on depression, 47 articles on anxiety and 13 articles on stress were included in the meta-analysis. The overall estimates for prevalence based on a random-effects model were as follows: depression, 19.2% (95% CI: 13.0 - 27.5%); anxiety, 16.5% (95% CI: 11.1 - 22.8%); and stress, 13.9% (95% CI: 5.5 - 30.9%). The highest prevalence of depression and anxiety was recorded in Africa. The prevalence of depression was higher in nursing homes, and stress was more prevalent in individuals with COVID-19 compared to other populations.

CONCLUSION

The findings revealed a high prevalence of depression, anxiety, and stress in the elderly population. Therefore, it is recommended that healthcare professionals and policymakers pay more attention to the prevention and management of these disorders in the elderly population.

Non-coding RNAs involved in the molecular pathology of Alzheimer's disease: a systematic review

Alzheimer's disease (AD) is the leading cause of dementia globally, having a pathophysiology that is complex and multifactorial. Recent findings highlight the significant role of non-coding RNAs (ncRNAs), specifically microRNAs (miRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and piwi-interacting RNAs (piRNAs) in the molecular mechanisms underlying AD. These ncRNAs are involved in critical biological processes such as cell proliferation, apoptosis, oxidative stress, amyloid-beta aggregation, tau phosphorylation, neuroinflammation, and autophagy, which are pivotal in AD development and progression. This systematic review aims to consolidate current scientific knowledge on the role of ncRNAs in AD, making it the first to encompass the four types of ncRNAs associated with the disease. Our comprehensive search and analysis reveal that ncRNAs not only play crucial roles in the pathogenesis of AD but also hold potential as biomarkers for its early detection and as novel therapeutic targets. Specifically, the findings underscore the significance of miRNAs in regulating genes involved in key AD pathways such as activin receptor signaling pathway, actomyosin contractile ring organization, and advanced glycation endproducts-receptor advanced glycation endproducts (AGE-RAGE) signaling pathway. This review also highlights the potential of ncRNAs in unveiling novel diagnostic and therapeutic strategies, emphasizing the need for further research to validate their clinical utility. Our systematic exploration provides a foundation for future bioinformatic analyses and the development of ncRNA-based precision medicine approaches for AD, offering new insights into the disease's molecular pathology and paving the way for innovative treatment strategies.

Systematic review registration

PROSPERO, https://www.crd.york.ac.uk/prospero/, CRD42022355307.

Intelligent prediction of Alzheimer's disease via improved multifeature squeeze-and-excitation-dilated residual network

This study aimed to address the issue of larger prediction errors existing in intelligent predictive tasks related to Alzheimer's disease (AD). A cohort of 487 enrolled participants was categorized into three groups: normal control (138 individuals), mild cognitive impairment (238 patients), and AD (111 patients) in this study. An improved multifeature squeeze-and-excitation-dilated residual network (MFSE-DRN) was proposed for two important AD predictions: clinical scores and conversion probability. The model was characterized as three modules: squeeze-and-excitation-dilated residual block (SE-DRB), multifusion pooling (MF-Pool), and multimodal feature fusion. To assess its performance, the proposed model was compared with two other novel models: ranking convolutional neural network (RCNN) and 3D vision geometrical group network (3D-VGGNet). Our method showed the best performance in the two AD predicted tasks. For the clinical scores prediction, the root-mean-square errors (RMSEs) and mean absolute errors (MAEs) of mini-mental state examination (MMSE) and AD assessment scale-cognitive 11-item (ADAS-11) were 1.97, 1.46 and 4.20, 3.19 within 6 months; 2.48, 1.69 and 4.81, 3.44 within 12 months; 2.67, 1.86 and 5.81, 3.83 within 24 months; 3.02, 2.03 and 5.09, 3.43 within 36 months, respectively. At the AD conversion probability prediction, the prediction accuracies within 12, 24, and 36 months reached to 88.0, 85.5, and 88.4%, respectively. The AD predication would play a great role in clinical applications.

Delineating mechanisms underlying parvalbumin neuron impairment in different neurological and neurodegenerative disorders: the emerging role of mitochondrial dysfunction

Given the current paucity of effective treatments in many neurological disorders, delineating pathophysiological mechanisms among the major psychiatric and neurodegenerative diseases may fuel the development of novel, potent treatments that target shared pathways. Recent evidence suggests that various pathological processes, including bioenergetic failure in mitochondria, can perturb the function of fast-spiking, parvalbumin-positive neurons (PV+). These inhibitory neurons critically influence local circuit regulation, the generation of neuronal network oscillations and complex brain functioning. Here, we survey PV+ cell vulnerability in the major neuropsychiatric, and neurodegenerative diseases and review associated cellular and molecular pathophysiological alterations purported to underlie disease aetiology.

Involvement of transposable elements in Alzheimer's disease pathogenesis

Alzheimer's disease affects an average of 5 % of the population with a significant increase in prevalence with age, suggesting that the same mechanisms that underlie aging may influence this pathology. Investigation of these mechanisms is promising for effective methods of treatment and prevention of the disease. Possible participants in these mechanisms are transposons, which serve as drivers of epigenetic regulation, since they form species-specific distributions of non-coding RNA genes in genomes in evolution. Study of miRNA involvement in Alzheimer's disease pathogenesis is relevant, since the associations of protein-coding genes (APOE4, ABCA7, BIN1, CLU, CR1, PICALM, TREM2) with the disease revealed as a result of GWAS make it difficult to explain its complex pathogenesis. Specific expression changes of many genes were found in different brain parts of Alzheimer's patients, which may be due to global regulatory changes under the influence of transposons. Experimental and clinical studies have shown pathological activation of retroelements in Alzheimer's disease. Our analysis of scientific literature in accordance with MDTE DB revealed 28 miRNAs derived from transposons (17 from LINE, 5 from SINE, 4 from HERV, 2 from DNA transposons), the expression of which specifically changes in this disease (decreases in 17 and increases in 11 microRNA). Expression of 13 out of 28 miRNAs (miR-151a, -192, -211, -28, -31, -320c, -335, -340, -378a, -511, -576, -708, -885) also changes with aging and cancer development, which indicates the presence of possible common pathogenetic mechanisms. Most of these miRNAs originated from LINE retroelements, the pathological activation of which is associated with aging, carcinogenesis, and Alzheimer's disease, which supports the hypothesis that these three processes are based on the primary dysregulation of transposons that serve as drivers of epigenetic regulation of gene expression in ontogeny.

Variability in Alzheimer's disease mortality from European vital statistics, 2012-2020

OBJECTIVE

Data regarding the trends in Alzheimer's disease (AD) mortality in the modern European Union (EU-27) member states are lacking. We assess the sex- and age-specific trends in AD mortality in the EU-27 member states between years 2012 and 2020.

METHODS

Data on cause-specific deaths and population numbers by sex for each country of the EU-27 were retrieved through publicly available European Statistical Office (EUROSTAT) dataset from 2012 to 2020. AD-related deaths were ascertained when the ICD-10 code G30 was listed as the primary cause of death in the medical death certificate. To calculate annual trends, we assessed the average annual percent change (AAPC) with relative 95% confidence intervals (CIs) using Joinpoint regression.

RESULTS

During the study period, 751,493 deaths (1.7%, 233,271 males and 518,222 females) occurred in the EU-27 because of AD. Trends in the proportion of AD-related deaths per 1000 total deaths slightly increased from 16.8% to 17.5% (p for trend <0.001). The age-adjusted mortality rate was higher in women over the entire study period. Joinpoint regression analysis revealed a stagnation in age-adjusted AD-related mortality from 2012 to 2020 among EU-27 Member States (AAMR: -0.1% [95% CI: -1.8-1.79], p = 0.94). Stratification by Country showed relevant regional disparities, especially in the Northern and Eastern EU-27 member states.

CONCLUSIONS

Over the last decade, the age-adjusted AD-related mortality rate has plateaued in EU-27. Important disparities still exist between Western and Eastern European countries.

Cognitive Screening and Hearing Assessment in Patients With Chronic Tinnitus

OBJECTIVES

The study aimed to assess the relationship of tinnitus with hyperacusis with cognitive impairment as indicated by the Montreal Cognitive Assessment (MoCA) tool.

METHODS

This multicenter cross-sectional study included individuals with chronic tinnitus from the "Unification of Treatments and Interventions for Tinnitus Patients" (UNITI) database. Participants were recruited from four different tertiary clinical centers located in Athens and Granada (Mediterranean group), as well as Berlin and Regensburg (German group). In total, 380 individuals with a diagnosis of non-pulsatile chronic tinnitus (permanent and constant tinnitus lasting more than 6 months) and no evidence of severe cognitive impairment (MoCA score >22) were enrolled. The evaluation utilized the following tools: MoCA, Tinnitus Handicap Inventory (THI), Hyperacusis Questionnaire (GÜF), Patient Health Questionnaire (PHQ-9), and the European School for Interdisciplinary Tinnitus Research Screening Questionnaire.

RESULTS

MoCA scores differed between German and Mediterranean individuals (P<0.01), necessitating separate analyses for each group. In both cohorts, MoCA scores were significantly associated with education level, age, hearing threshold at 8 kHz, and THI. Furthermore, a significant correlation was observed between PHQ-9 scores and both THI and GÜF (P<0.01 for both Germans and those from the Mediterranean).

CONCLUSION

Our data suggest an association between tinnitus handicap, high-frequency hearing loss, and mild cognitive impairment. Additionally, PHQ-9 scores were associated with tinnitus and hyperacusis scores, independent of hearing loss thresholds.

[Immunological and neuroanatomic markers of the clinical dynamics of MCI and pre-MCI]

OBJECTIVE

To study the relationship of the parameters of immunity and systemic inflammation with the structural magnetic resonance imaging (MRI) parameters in patients with mild cognitive impairment (MCI) and pre-MCI undergoing neurocognitive rehabilitation to search for candidate markers of its effectiveness.

MATERIAL AND METHODS

The main group included 49 patients, aged ≥60 years, with MCI and pre-MCI with memory impairment, who underwent a course of neurorehabilitation for 5 weeks. The control group included 19 volunteers of similar age with a total MoCA score of ≥25, who did not have cognitive impairment and immuno-inflammatory disorders. The parameters of cellular and humoral immunity and markers of inflammation were studied, and structural MRI was performed.

RESULTS

The content of activated natural killer cells (NK-cells) was increased in MCI and pre-MCI (0.63±0.12% vs. 0.22±0.07% in the control group, p=2.2·10-7). The level of immunoglobulin G (IgG) <12.5 g/l in patients with MCI and pre-MCI with the Montreal Cognitive Assessment Scale (MoCA) score <22 was associated with a decrease in the volume of the right nucleus accumbens (376±35 mm3 in patients with IgG <12.5 g/l (p=0.0013) and 480±44 mm3 at IgG <12.5 g/l, 480±44 mm3 in the control group), as well as with a decrease of the thickness and volume of a number of other cortical zones. A logistic regression model including the level of immunoglobulin G, NK cells, CD8+ NK cells and right amygdala volume was constructed to predict the number of MoCA scores 6 months after the course of rehabilitation (R2=0.57; p<1·10-5; standard error of estimate: 2.93).

CONCLUSION

As a result of this work, the perspectives of assessing the immunological parameters in combination with socio-demographic data and morphometric changes of the brain as potential prognostic markers of the dynamics of cognitive impairment in patients with MCI and pre-MCI after neurorehabilitation has been shown.

Estimating the prevalence of diagnosed Alzheimer disease in England across deprivation groups using electronic health records: a clinical practice research datalink study

OBJECTIVE

Estimate the prevalence of diagnosed Alzheimer's disease (AD) and early Alzheimer's disease (eAD) overall and stratified by age, sex and deprivation and combinations thereof in England on 1 January 2020.

DESIGN

Cross-sectional.

SETTING

Primary care electronic health record data, the Clinical Practice Research database linked with secondary care data, Hospital Episode Statistics (HES) and patient-level deprivation data, Index of Multiple Deprivation (IMD).

OUTCOME MEASURES

The prevalence per 100 000 of the population and corresponding 95% CIs for both diagnosed AD and eAD overall and stratified by covariates. Sensitivity analyses were conducted to assess the sensitivity of the population definition and look-back period.

RESULTS

There were 448 797 patients identified in the Clinical Practice Research Datalink that satisfied the study inclusion criteria and were eligible for HES and IMD linkage. For the main analysis of AD and eAD, 379 763 patients are eligible for inclusion in the denominator. This resulted in an estimated prevalence of diagnosed AD of 378.39 (95% CI, 359.36 to 398.44) per 100 000 and eAD of 292.81 (95% CI, 276.12 to 310.52) per 100 000. Prevalence estimates across main and sensitivity analyses for the entire AD study population were found to vary widely with estimates ranging from 137.48 (95% CI, 127.05 to 148.76) to 796.55 (95% CI, 768.77 to 825.33). There was significant variation in prevalence of diagnosed eAD when assessing the sensitivity with the look-back periods, as low as 120.54 (95% CI, 110.80 to 131.14) per 100 000, and as high as 519.01 (95% CI, 496.64 to 542.37) per 100 000.

CONCLUSIONS

The study found relatively consistent patterns of prevalence across both AD and eAD populations. Generally, the prevalence of diagnosed AD increased with age and increased with deprivation for each age category. Women had a higher prevalence than men. More granular levels of stratification reduced patient numbers and increased the uncertainty of point prevalence estimates. Despite this, the study found a relationship between deprivation and prevalence of AD.

Subjective cognitive decline is a better marker for future cognitive decline in females than in males

BACKGROUND

The identification of biomarkers for early detection of Alzheimer's disease (AD) is critical to the development of therapies and interventions targeted at symptom management and tracking the pathophysiology of disease. The endorsement of subjective cognitive decline (SCD) has emerged as a potential indicator of early change in cognitive status that may be predictive of future impairment at a time when measurable declines in neuropsychological performance cannot be detected. While there are numerous findings revealing sex differences in the prevalence of AD, there is a paucity of research examining sex differences in SCD. Therefore, the goal of this project was to determine if the relationship between the endorsement of SCD and future cognitive changes differ as a function of biological sex.

METHODS

A sample of 3019 male and female healthy older adults (2188 without SCD, 831 with SCD), with a mean follow-up time of 5.7 years, were included from the Rush Alzheimer's Disease Center Research Sharing Hub. Linear regressions were performed to determine group differences in baseline cognitive scores, while linear mixed-effects models were completed to determine group differences in the rate of cognitive change over time.

RESULTS

Individuals endorsing SCD had significantly lower baseline cognitive scores and increased rates of decline in all cognitive domains compared to those without SCD. Males exhibited significantly lower scores in baseline performance in global cognition, episodic memory, and perceptual speed regardless of SCD classification. Females with SCD were found to decline at significantly faster rates than both males with SCD and males and females without SCD in all cognitive domains over a maximum 15-year follow-up period.

CONCLUSIONS

SCD is related to lower baseline cognitive performance and faster cognitive decline compared to those who do not endorse SCD. Females with SCD have the fastest rate of decline suggesting that SCD may be more predictive of future decline in females than in males. Targeted assessments of SCD may allow for the identification of individuals for inclusion in intervention trials, and other research studies, aiming to attenuate casual disease processes, which may ultimately aid in the mitigation of sex disparities in AD.

Bright, but allergic and neurotic? A critical investigation of the "overexcitable genius" hypothesis

Introduction

Higher intelligence has been associated with improved health and longevity. However, recent findings have claimed that exceptional intelligence may come at a cost. Individuals at the upmost end of the intelligence distribution are reported to be disproportionately afflicted by a set of stress-related physical and mental health conditions: so-called overexcitabilities. Few accounts have investigated this issue and no studies are available for non-US samples yet. Here, we aimed to replicate and extend previous work by examining hitherto unaddressed overexcitabilities in a European high-IQ sample.

Methods

We carried out a preregistered survey among members of MENSA, the world's largest high-IQ society. In total, 615 (307 male) members from Austria, Germany, Hungary, Switzerland, and the United Kingdom participated.

Results and Discussion

Compared to the general population, our sample exhibited considerably elevated prevalences in autism spectrum disorders (risk ratio/RR = 2.25), chronic fatigue syndrome (RR = 5.69), depression (RR = 4.38), generalized anxiety (RR = 3.82), and irritable bowel syndrome (RR = 3.76). Contrary to previous accounts, neither asthma, allergies, nor autoimmune diseases were elevated. We show that this subsample of intellectually gifted persons faces specific health challenges compared to the general population. The reasons for this remain speculative, as we find little evidence for previously proposed immunological explanations. However, it is possible that the effects are caused by sample selectiveness (i.e., membership in a high-IQ society) rather than high IQ itself.

Immunosenescence in Neurological Diseases-Is There Enough Evidence?

The aging of the immune system has recently attracted a lot of attention. Immune senescence describes changes that the immune system undergoes over time. The importance of immune senescence in neurological diseases is increasingly discussed. For this review, we considered studies that investigated cellular changes in the aging immune system and in neurological disease. Twenty-six studies were included in our analysis (for the following diseases: multiple sclerosis, stroke, Parkinson's disease, and dementia). The studies differed considerably in terms of the patient groups included and the cell types studied. Evidence for immunosenescence in neurological diseases is currently very limited. Prospective studies in well-defined patient groups with appropriate control groups, as well as comprehensive methodology and reporting, are essential prerequisites to generate clear insights into immunosenescence in neurological diseases.

Sex differences in predictors and regional patterns of brain age gap estimates

The brain-age-gap estimate (brainAGE) quantifies the difference between chronological age and age predicted by applying machine-learning models to neuroimaging data and is considered a biomarker of brain health. Understanding sex differences in brainAGE is a significant step toward precision medicine. Global and local brainAGE (G-brainAGE and L-brainAGE, respectively) were computed by applying machine learning algorithms to brain structural magnetic resonance imaging data from 1113 healthy young adults (54.45% females; age range: 22-37 years) participating in the Human Connectome Project. Sex differences were determined in G-brainAGE and L-brainAGE. Random forest regression was used to determine sex-specific associations between G-brainAGE and non-imaging measures pertaining to sociodemographic characteristics and mental, physical, and cognitive functions. L-brainAGE showed sex-specific differences; in females, compared to males, L-brainAGE was higher in the cerebellum and brainstem and lower in the prefrontal cortex and insula. Although sex differences in G-brainAGE were minimal, associations between G-brainAGE and non-imaging measures differed between sexes with the exception of poor sleep quality, which was common to both. While univariate relationships were small, the most important predictor of higher G-brainAGE was self-identification as non-white in males and systolic blood pressure in females. The results demonstrate the value of applying sex-specific analyses and machine learning methods to advance our understanding of sex-related differences in factors that influence the rate of brain aging and provide a foundation for targeted interventions.

The cognitive performance in the Phototest is predictor of biological markers of Alzheimer's disease

BACKGROUND

The abnormal cerebrospinal fluid levels of biomarkers, such as β-amyloid and phosphorylated tau (pTau), support the biological diagnosis of Alzheimer Disease (AD) independently of its clinical stage. However, this invasive exam cannot be extensively applied and requires previous sound clinical screen that can be based on brief, well validated cognitive tests, such as the Phototest.

OBJECTIVE

To evaluate the association of partial (naming [NA], total recall [TR], free recall [FR], and verbal fluency) and total scores of the Phototest with the biological diagnosis of AD and the potential use of this test as a screening tool in the clinical work up.

DESIGN

Retrospective study of Individuals attending a Memory Clinic who were applied the Phototest and classified, according to cerebrospinal fluid biomarkers (β-amyloid1-42 and pTau), in the biological AD continuum stage (ContAD) as "no AD" (A-), "AD changes" (A+T-) or "AD" (A+T+). Multivariate analyses were conducted with one fixed factor, ContAD, and partial and total Phototest scores. The area under the receiver operating characteristics curve (AUC) was calculated to estimate the capacity of Phototest scores to predict amyloidosis (A+) and AD.

RESULTS

The study included 170 individuals (92 A-, 23 A+T- and 55 A+T+). FR (7.9, 0.01 [F,p]) and TR (8.1, 0.001) scores were associated with ContAD and had a moderate ability (AUC 0.71-0.74) to detect the presence of "A+" or "AD".

CONCLUSIONS

Partial memory scores of Phototest are associated with ContAD. They predict acceptably the presence of abnormal levels of β-amyloid and AD signature in CSF and can be useful to support further biological diagnostic tests.

Sex and gender differences in dementia

The dementia landscape has undergone a striking paradigm shift. The advances in understanding of neurodegeneration and proteinopathies has changed our approach to patients with cognitive impairment. Firstly, it has recently been shown that the various proteinopathies that are the cause of the dementia begin to build up long before the appearance of any obvious symptoms. This has cemented the idea that there is an urgency in diagnosis as it occurs very late in the pathophysiology of these diseases. Secondly, that accurate diagnosis is required to deliver targeted therapies, that is precision medicine. With this latter point, the realization that various factors of a person need to be considered as they may impact the presentation and progression of disease has risen to the forefront. Two of these factors aside from race and age are biological sex and gender (social construct), as both can have tremendous impact on manifestation of disease. This chapter will cover what is known and remains to be known on the interaction of sex and gender with some of the major causes of dementia.

Subjective Cognitive Decline and its Relation to Verbal Memory and Sex in Cognitively Unimpaired Individuals from a Colombian Cohort with Autosomal-Dominant Alzheimer's Disease

OBJECTIVE

Subjective Cognitive Decline (SCD) may be an early indicator of risk for Alzheimer's disease (AD). Findings regarding sex differences in SCD are inconsistent. Studying sex differences in SCD within cognitively unimpaired individuals with autosomal-dominant AD (ADAD), who will develop dementia, may inform sex-related SCD variations in preclinical AD. We examined sex differences in SCD within cognitively unimpaired mutation carriers from the world's largest ADAD kindred and sex differences in the relationship between SCD and memory performance.

METHODS

We included 310 cognitively unimpaired Presenilin-1 (PSEN-1) E280A mutation carriers (51% females) and 1998 noncarrier family members (56% females) in the study. Subjects and their study partners completed SCD questionnaires and the CERAD word list delayed recall test. ANCOVAs were conducted to examine group differences in SCD, sex, and memory performance. In carriers, partial correlations were used to examine associations between SCD and memory performance covarying for education.

RESULTS

Females in both groups had greater self-reported and study partner-reported SCD than males (all p < 0.001). In female mutation carriers, greater self-reported (p = 0.02) and study partner-reported SCD (p < 0.001) were associated with worse verbal memory. In male mutation carriers, greater self-reported (p = 0.03), but not study partner-reported SCD (p = 0.11) was associated with worse verbal memory.

CONCLUSIONS

Study partner-reported SCD may be a stronger indicator of memory decline in females versus males in individuals at risk for developing dementia. Future studies with independent samples and preclinical trials should consider sex differences when recruiting based on SCD criteria.

Modeling of SGLT1 in Reconstituted Systems Reveals Apparent Ion-Dependencies of Glucose Uptake and Strengthens the Notion of Water-Permeable Apo States

The reconstitution of secondary active transporters into liposomes shed light on their molecular transport mechanism. The latter are either symporters, antiporters or exchangers, which use the energy contained in the electrochemical gradient of ions to fuel concentrative uptake of their cognate substrate. In liposomal preparations, these gradients can be set by the experimenter. However, due to passive diffusion of the ions and solutes through the membrane, the gradients are not stable and little is known on the time course by which they dissipate and how the presence of a transporter affects this process. Gradient dissipation can also generate a transmembrane potential (VM). Because it is the effective ion gradient, which together with VM fuels concentrative uptake, knowledge on how these parameters change within the time frame of the conducted experiment is key to understanding experimental outcomes. Here, we addressed this problem by resorting to a modelling approach. To this end, we mathematically modeled the liposome in the assumed presence and absence of the sodium glucose transporter 1 (SGLT1). We show that 1) the model can prevent us from reaching erroneous conclusions on the driving forces of substrate uptake and we 2) demonstrate utility of the model in the assignment of the states of SGLT1, which harbor a water channel.

The Comparative Efficacy of Multiple Acupuncture for Alzheimer's Disease: A Bayesian Network Meta-Analysis

Background

Alzheimer's disease (AD) is a progressive neurodegenerative disease. Numerous cases have illustrated that the acupuncture method could improve AD patients' cognitive function and daily living ability. However, the optimal acupuncture treatments remain controversial. Therefore, we aimed to conduct a systematic review to compare the efficacy of multiple acupuncture therapies for AD and identify the optimal acupuncture intervention for delaying AD progression.

Methods

To select potentially concerned randomized controlled trials (RCTs), we searched four English databases, four Chinese databases, and additional sources from 1 May 2021. Two independent reviewers conducted study screening, data extraction, and methodological quality assessment. The primary outcome was global cognitive function improvement. Pairwise and Bayesian network meta-analyses were performed using STATA v15.0 and ADDIS v1.16.8. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) tool was used to assess the quality of evidence.

Results

This study included 34 RCTs with 2,071 participants. Regarding global cognitive function improvement, the pairwise meta-analysis confirmed that electronic acupuncture (EA) plus conventional medicine (CM) and manual acupuncture (MA) plus CM were statistically significantly different from CM, and EA plus CM was ranked as the best combination in the network meta-analysis. In terms of response rate, MA outperformed CM statistically significantly; warm acupuncture (WA) was ranked as the best in the network meta-analysis. Regarding activity of daily living improvement, EA plus CM, MA plus CM, and fire acupuncture plus CM, MA, and scalp acupuncture were statistically significantly different from CM, and EA plus CM was ranked as the best combination in the network meta-analysis. However, the evidences were ranked as low to critically low.

Conclusions

Acupuncture, as a monotherapy or an adjuvant therapy, may have a beneficial effect on efficacy for AD. EA plus CM may be the optimal acupuncture therapy for AD and should be administered to AD patients. It may aid and support patient, operative, and societal decision-making. Due to the dearth of high-quality evidence, additional high-quality studies should be conducted to ensure these findings in the future. This study is registered with PROSPERO (CRD42021252305).

The congruency of neuropsychological and F18-FDG brain PET/CT diagnostics of Alzheimer's Disease (AD) in routine clinical practice: insights from a mixed neurological patient cohort

Background

Diagnostics of Alzheimer’s Disease (AD) require a multimodal approach. Neuropsychologists examine the degree and etiology of dementia syndromes and results are combined with those of cerebrospinal fluid markers and imaging data. In the diagnostic process, neuropsychologists often rely on anamnestic and clinical information, as well as cognitive tests, prior to the availability of exhaustive etiological information. The congruency of this phenomenological approach with results from FDG-PET/CT examinations remains to be explored. The latter yield highly accurate diagnostic information.

Method

A mixed sample of N = 127 hospitalized neurological patients suspected of displaying a dementia syndrome underwent extensive neuropsychological and FDG-PET/CT examinations. Neuropsychological examinations included an anamnestic and clinical interview, and the CERAD cognitive test battery. Two decisional approaches were considered: First, routine diagnostic results were obtained, i.e. the final clinical decision of the examining neuropsychologist (AD_Clinical vs. non-AD_Clinical). Secondly, a logistic regression model was implemented, relying on CERAD profiles alone. CERAD subscales that best predicted AD based on FDG-PET/CT were identified and a nominal categorization obtained (AD_Test vs. non-AD_Test). Congruency of results from both approaches with those of the FDG-PET/CT (AD_PET vs. non-AD_PET) were estimated with Cohen’s Kappa (κ) and Yule’s Y coefficient of colligation. Descriptive estimates of accuracy, sensitivity and specificity of CERAD relative to FDG-PET/CT diagnostics were derived.

Results

AD_PET patients constituted N = 33/127 (26%) of the sample. The clinical decision approach (AD_Clinical vs. non-AD_Clinical) showed substantial agreement with the FDG-PET/CT classification (κ = .69, Y = .72) involving good accuracy (84.2%), moderate sensitivity (75.8%) and excellent specificity (92.6%). In contrast, the decisional approach that relied on CERAD data alone (AD_Test vs. non-AD_Test) involved only moderate agreement with the FDG-PET/CT (κ = .54, Y = .62) with lower accuracy (74.8%), attributable to decreased sensitivity (56.3%) and comparable specificity (93.3%).

Conclusions

It is feasible to identify AD through a comprehensive neuropsychological examination in a mixed sample of neurological patients. However, within the boundaries of methods applied here, decisions based on cognitive test results alone appear limited. One may conclude that the clinical impression based on anamnestic and clinical information obtained by the neuropsychological examiner plays a crucial role in the identification of AD patients in routine clinical practice.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02614-4.

Reproducibility of developmental neuroplasticity in in vitro brain tissue models

The current prevalence of neurodevelopmental, neurodegenerative diseases, stroke and brain injury stimulates studies aimed to identify new molecular targets, to select the drug candidates, to complete the whole set of preclinical and clinical trials, and to implement new drugs into routine neurological practice. Establishment of protocols based on microfluidics, blood-brain barrier- or neurovascular unit-on-chip, and microphysiological systems allowed improving the barrier characteristics and analyzing the regulation of local microcirculation, angiogenesis, and neurogenesis. Reconstruction of key mechanisms of brain development and even some aspects of experience-driven brain plasticity would be helpful in the establishment of brain in vitro models with the highest degree of reliability. Activity, metabolic status and expression pattern of cells within the models can be effectively assessed with the protocols of system biology, cell imaging, and functional cell analysis. The next generation of in vitro models should demonstrate high scalability, 3D or 4D complexity, possibility to be combined with other tissues or cell types within the microphysiological systems, compatibility with bio-inks or extracellular matrix-like materials, achievement of adequate vascularization, patient-specific characteristics, and opportunity to provide high-content screening. In this review, we will focus on currently available and prospective brain tissue in vitro models suitable for experimental and preclinical studies with the special focus on models enabling 4D reconstruction of brain tissue for the assessment of brain development, brain plasticity, and drug kinetics.

Effects of gut microbiota and probiotics on Alzheimer’s disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disease with high morbidity, disability, and fatality rate, significantly increasing the global burden of public health. The failure in drug discovery over the past decades has stressed the urgency and importance of seeking new perspectives. Recently, gut microbiome (GM), with the ability to communicate with the brain bidirectionally through the microbiome–gut–brain axis, has attracted much attention in AD-related studies, owing to their strong associations with amyloids, systematic and focal inflammation, impairment of vascular homeostasis and gut barrier, mitochondrial dysfunction, etc., making the regulation of GM, specifically supplementation of probiotics a promising candidate for AD treatment. This article aims to review the leading-edge knowledge concerning potential roles of GM in AD pathogenesis and of probiotics in its treatment and prevention.

MRI Deep Learning-Based Solution for Alzheimer's Disease Prediction

BACKGROUND

Alzheimer's is a degenerative dementing disorder that starts with a mild memory impairment and progresses to a total loss of mental and physical faculties. The sooner the diagnosis is made, the better for the patient, as preventive actions and treatment can be started. Although tests such as the Mini-Mental State Tests Examination are usually used for early identification, diagnosis relies on magnetic resonance imaging (MRI) brain analysis.

METHODS

Public initiatives such as the OASIS (Open Access Series of Imaging Studies) collection provide neuroimaging datasets openly available for research purposes. In this work, a new method based on deep learning and image processing techniques for MRI-based Alzheimer's diagnosis is proposed and compared with previous literature works.

RESULTS

Our method achieves a balance accuracy (BAC) up to 0.93 for image-based automated diagnosis of the disease, and a BAC of 0.88 for the establishment of the disease stage (healthy tissue, very mild and severe stage).

CONCLUSIONS

Results obtained surpassed the state-of-the-art proposals using the OASIS collection. This demonstrates that deep learning-based strategies are an effective tool for building a robust solution for Alzheimer's-assisted diagnosis based on MRI data.

The Influence of Nutrition in Alzheimer's Disease: Neuroinflammation and the Microbiome vs. Transmissible Prion

Alzheimer's disease (AD) is a primary, progressive, neurodegenerative disorder. Many risk factors for the development of AD have been investigated, including nutrition. Although it has been proven that nutrition plays a role in AD, the precise mechanisms through which nutrition exerts its influence remain undefined. The object of this study is to address this issue by elucidating some of the mechanisms through which nutrition interacts with AD. This work is a qualitative systematic bibliographic review of the current literature searchable on various available databases, including PubMed, Web of Science, and Google Scholar. Our evidence comprises 31 articles selected after a systematic search process. Patients suffering with AD present a characteristic microbiome that promotes changes in microglia generating a proinflammatory state. Many similarities exist between AD and prion diseases, both in terms of symptoms and in the molecular mechanisms of pathogenesis. Changes in the composition of the gut microbiome due to dietary habits could be one of the environmental factors affecting the development of AD; however, this is probably not the only factor. Similarly, the mechanism for self-propagation of beta-amyloid seen in AD is similar to that seen in prions.

Dietary sugar intake and risk of Alzheimer's disease in older women

BACKGROUND

Despite some reports of cardiometabolic disorders associated with the risk of Alzheimer's disease (AD), limited studies have been conducted to examine the association between excessive sugar intake (a risk factor for cardiometabolic disorders) and AD risk.

AIM

The purpose of our study was to evaluate if excessive sugar intake has a significant long-term effect on the risk of AD.

METHODS

A population sample of 37,689 participants, who enrolled in the United States (US) Women's Health Initiative - Dietary Modification Trial (WHI-DM) in 1993-2005 and its extended observational follow-up study through 1 March 2019, were analyzed. Dietary sugar intake was measured using food frequency questionnaires. AD was classified by reports using a standard questionnaire. A dietary pattern that explained the maxima variations in sugar intake was constructed using reduced rank regression (RRR) technique. Associations of RRR dietary pattern scores and sugar intake (g/day) by quartiles (Q1 through Q4) with AD risk were examined using Cox proportional hazards regression analysis with adjusting for key covariates.

RESULTS

During a mean follow-up of 18.7 years, 4586 participants reported having incident AD. The total incidence rate (95% confidence interval [CI]) of AD was 6.5 (6.3-6.7) per 1000 person-years (PYs). The incidence rates (95% CI) of AD by total sugar intake were 6.2 (5.8-6.6), 6.4 (6.0-6.8), 6.6 (6.3-7.0), and 6.9 (6.5-7.3) per 1000 PYs among those in quartiles (Q) 1 to Q4 (toward higher sugar consumption) of total sugar intake, respectively (test for trend of AD incident rates, p < 0.001). Individuals in Q4 of total sugar intake had a 1.19 higher risk of incident AD than those in Q1 (hazard ratio [HR] = 1.19, 95% CI: 1.05-1.34, p = 0.01). An estimated increase of 10 g/day in total sugar intake (about 2.4 teaspoons) was associated with an increased AD risk by 1.3-1.4%. Of six subtypes of sugar intake, lactose was significantly associated with AD risk.

CONCLUSIONS

Our study indicates that excessive total sugar intake was significantly associated with AD risk in women. Of six subtypes of sugar intake, lactose had a stronger impact on AD risk.

Prevalence of Dementia in Older Adults in Central and Eastern Europe: A Systematic Review and Meta-Analysis

Data on dementia prevalence in Europe are primarily based on studies from Western Europe. Central and Eastern European countries differ from Western European countries in their average income and other socioeconomic and health factors that are relevant for dementia risk. We, therefore, conducted a systematic review of population-based studies on prevalence of dementia in Central and Eastern Europe. We searched in electronic databases from the date of inception up to July 2019, updated in October 2020. We hand-searched references of included articles and contacted experts in each country to identify further articles. We combined studies by meta-analysis where possible. Ten population-based studies (n = 30,268) met inclusion criteria. We meta-analysed seven studies (n = 11,994). The selected studies were conducted across 5 countries with no studies identified for the vast majority of countries in this region. Prevalence of all-cause dementia was 6.7% (95% CI 5.1–8.2) in those aged 60 or over, and 7.1% (95% CI 5.1–9.2) in those aged 65 and over. Prevalence rates were similar to those in Western Europe, but are increasing over time, compared with the patterns of reduction in age-specific prevalence in Western Europe.

The Neuroprotective Effect of Byu d Mar 25 in LPS-Induced Alzheimer's Disease Mice Model

Inflammatory factors play an important role in the pathogenesis of Alzheimer's disease (AD). Byu d Mar 25 (BM25) has been suggested to have protective effects in the central nervous system. However, the effect of BM25 on AD has not been determined. This study aims to investigate the neuroprotective effect of BM25 in AD. A total of 40 AD model mice were randomly assigned to the following five groups (n = 8 per group): the AD + NS group, the AD + donepezil group, and three AD + BM25 groups treated with either 58.39 mg/kg (AD + BM25-L), 116.77 mg/kg (AD + BM25-M), or 233.54 mg/kg BM25 (AD + BM25-H). The Morris water maze test was performed to assess alterations in spatial learning and memory deficits. Nissl staining was performed to detect Nissl bodies and neuronal damage. The expression of IL-1β and TNF-α was evaluated by ELISA. The protein expression of P-P38, P38, P-IκBα, caspase 1, COX2, and iNOS was determined by western blotting. The expression of Aβ, p-Tau, and CD11b was measured by immunohistochemistry. The mRNA expression levels of IL-1β, TNF-α, COX2, and iNOS were measured by qRT-PCR. Spatial memory significantly improved in the AD + BM25-M and AD + BM25-H groups compared with the AD + NS group (p < 0.05). The expression of Aβ and p-Tau significantly decreased in the AD + BM25-M and AD + BM25-H groups (p < 0.05). The neuron density and hierarchy and number of pyramidal neurons significantly increased in the AD + BM25-M and AD + BM25-H groups (p < 0.05). In addition, the expression levels of CD11b, IL-1β, TNF-α, COX2, iNOS, caspase 1, p-IκBα, and p-P38 significantly decreased in the AD + BM25-M and AD + BM25-H groups (p < 0.05). In conclusion, our findings suggest that BM25 may exert anti-inflammatory and neuroprotective effects in AD model mice by suppressing the activity of microglia and inhibiting the phosphorylation of IκBα and p38 MAPK.

Effects of short- and long-term neurostimulation (tDCS) on Alzheimer's disease patients: two randomized studies

BACKGROUND

Non-invasive brain stimulation is an effective treatment for Alzheimer's disease.

AIMS

The purpose of the two studies presented here is to compare the short- and long-term effects of transcranial direct current stimulation (t-DCS) on two samples of advanced AD patients.

METHODS

In Study 1 26 patients were involved in a 10-day anodal vs. sham tDCS intervention stimulating the left frontotemporal cortex. A pre-post test assessment was run using two different neurocognitive tests and EEG data. The same protocol was used in Study 2, which involved 18 different patients who underwent the same intervention 10 days a month for 8 months.

RESULTS

Results confirmed how the t-DCS intervention was effective both in the short- and the long-term to slow down the progression of AD on specific neurophysiological domains and, to a certain extent, on neurophysiological activity. Discussion tDCS appear to be effective and to affect differently neurocognitive and neurophysiological functions when comparing short and long-term outcomes. Conclusions Anodal-tDCS is an effective way to slow down the progression of Alzheimer's both in the short and long term. It can also affect the EEG patterns, but this requires a more protracted intervention.

Fine Particle Exposure and Clinical Aggravation in Neurodegenerative Diseases in New York State

BACKGROUND

Adult-onset neurodegenerative diseases affect millions and negatively impact health care systems worldwide. Evidence suggests that air pollution may contribute to aggravation of neurodegeneration, but studies have been limited.

OBJECTIVE

We examined the potential association between long-term exposure to particulate matter ≤ 2.5 μ m in aerodynamic diameter [fine particulate matter (PM 2.5 )] and disease aggravation in Alzheimer's (AD) and Parkinson's (PD) diseases and amyotrophic lateral sclerosis (ALS), using first hospitalization as a surrogate of clinical aggravation.

METHODS

We used data from the New York Department of Health Statewide Planning and Research Cooperative System (SPARCS 2000-2014) to construct annual county counts of first hospitalizations with a diagnosis of AD, PD, or ALS (total, urbanicity-, sex-, and age-stratified). We used annual PM 2.5 concentrations estimated by a prediction model at a 1 -km 2 resolution, which we aggregated to population-weighted county averages to assign exposure to cases based on county of residence. We used outcome-specific mixed quasi-Poisson models with county-specific random intercepts to estimate rate ratios (RRs) for a 1-y PM 2.5 exposure. We allowed for nonlinear exposure-outcome relationships using penalized splines and accounted for potential confounders.

RESULTS

We found a positive nonlinear PM 2.5 - PD association that plateaued above 11   μ g / m 3 (RR = 1.09 , 95% CI: 1.04, 1.14 for a PM 2.5 increase from 8.1 to 10.4   μ g / m 3 ). We also found a linear PM 2.5 - ALS positive association (RR = 1.05 , 95% CI: 1.01, 1.09 per 1 - μ g / m 3 PM 2.5 increase), and suggestive evidence of an association with AD. We found effect modification by age for PD and ALS with a stronger positive association in patients < 70  years of age but found insufficient evidence of effect modification by sex or urbanization level for any of the outcomes.

CONCLUSION

Our findings suggest that annual increase in county-level PM 2.5 concentrations may contribute to clinical aggravation of PD and ALS. Importantly, the average annual PM 2.5 concentration in our study was 8.1   μ g / m 3 , below the current American national standards, suggesting the standards may not adequately protect the aging population. https://doi.org/10.1289/EHP7425.

Incidence, gender influence, and neuropsychological predictors of all cause dementia in the Faroe Islands-the Faroese Septuagenarian cohort

BACKGROUND

Using the Faroese Septuagenarian cohort, we aimed to describe the incidence of dementia and assess the validity of neurocognitive tests to predict subsequent dementia diagnosis.

METHODS

In this population-based cohort, 713 Faroese septuagenarians aged 70-74 years without dementia, underwent clinical and neuropsychological examinations. After 10-years of follow-up, information was collected on all participants referred for cognitive evaluations and diagnosed with dementia. Incidence rates were calculated and presented with 95% confidence intervals (CIs), assuming a Poisson distribution. We then performed discriminant analysis to determine the best set of neuropsychological tests to identify those who would develop dementia.

RESULTS

Over the 10-years, 65 participants (9.1%) were diagnosed with dementia, with a 10-year incidence rate of 1063 cases per 100,000 person years (95% CI 825, 1343). Women had a greater incidence than men (incidence rate ratio (IRR) = 1.58; 95% CI 0.93, 2.71). After stepwise selection, gender and six neuropsychological measures were selected to discriminate between those who would and would not develop dementia. Overall, the model was able to correctly identify 82% of those who would not develop dementia (specificity) and 71% of those who would (sensitivity).

CONCLUSIONS

These results indicate that among a greater number of tests covering a broad range of cognitive abilities, tests reflecting verbal and visual learning and recall, visuospatial function, attention, and encoding into and retrieval from long-term memory may be helpful in identifying patients in the pre-symptomatic phase of dementia. Thus, helping care-givers identify patients at a higher risk of developing dementia and adjusting management of care accordingly.

Dynamic Neuroimmune Profile during Mid-life Aging in the Female Brain and Implications for Alzheimer Risk

Aging and endocrine transition states can significantly impact inflammation across organ systems. Neuroinflammation is well documented in Alzheimer disease (AD). Herein, we investigated neuroinflammation that emerges during mid-life aging, chronological and endocrinological, in the female brain as an early initiating mechanism driving AD risk later in life. Analyses were conducted in a translational rodent model of mid-life chronological and endocrinological aging followed by validation in transcriptomic profiles from women versus age-matched men. In the translational model, the neuroinflammatory profile of mid-life aging in females was endocrine and chronological state specific, dynamic, anatomically distributed, and persistent. Microarray dataset analyses of aging human hippocampus indicated a sex difference in neuroinflammatory profile in which women exhibited a profile comparable to the pattern discovered in our translational rodent model, whereas age-matched men exhibited a profile consistent with low neuroimmune activation. Translationally, these findings have implications for therapeutic interventions during mid-life to decrease late-onset AD risk.

Changing patient profile, hearing aid use and disability among first-time hearing aid users in Singapore over a decade

OBJECTIVES

To examine the time trends in demographics, hearing characteristics, hearing aid (HA) choices, usage and patient-reported disability among first-time HA users in Singapore over a decade.

DESIGN

Cross-sectional study. Study sample: 1052 subjects issued with HAs at a tertiary hospital from 2004 to 2013.

RESULTS

An increase in number of first time HA users were seen from 2004 to 2013. Although mean age did not change significantly, the proportion of older adults (>80 years) being fitted increased (p for trend = 0.033). Inflation adjusted cost of HAs rose over time (p < 0.001 for trend). Bilateral HA uptake increased (adjusted odds ratio [AOR] = 1.58 (95% Confidence Interval [CI] 1.35-1.85) while use of customisable HAs decreased (AOR = 0.74, 95% CI 0.66-0.84) over the period. A decrease in the proportion of subjects reporting 5 or more disabilities (AOR = 0.45, 95% CI 0.34-0.59) and using their HAs >7 hours daily (AOR = 0.45, 95% CI 0.34-0.59) was seen.

CONCLUSION

From 2004 to 2013, there was a positive trend towards HA uptake in Singapore. Bilateral HA uptake increased while customisable in ear type of HA use decreased. While hearing disability showed a decreasing trend, HA usage remained suboptimal.

Is it time to use real-world data from primary care in Alzheimer's disease?

BACKGROUND

The analysis of real-world data in clinical research is rising, but its use to study dementia subtypes has been hardly addressed. We hypothesized that real-world data might be a powerful tool to update AD epidemiology at a lower cost than face-to-face studies, to estimate the prevalence and incidence rates of AD in Catalonia (Southern Europe), and to assess the adequacy of real-world data routinely collected in primary care settings for epidemiological research on AD.

METHODS

We obtained data from the System for the Development of Research in Primary Care (SIDIAP) database, which contains anonymized information of > 80% of the Catalan population. We estimated crude and standardized incidence rates and prevalences (95% confidence intervals (CI)) of AD in people aged at least 65 years living in Catalonia in 2016.

RESULTS

Age- and sex-standardized prevalence and incidence rate of AD were 3.1% (95%CI 2.7-3.6) and 4.2 per 1000 person-years (95%CI 3.8-4.6), respectively. Prevalence and incidence were higher in women and in the oldest people.

CONCLUSIONS

Our incidence and prevalence estimations were slightly lower than the recent face-to-face studies conducted in Spain and higher than other analyses of electronic health data from other European populations. Real-world data routinely collected in primary care settings could be a powerful tool to study the epidemiology of AD.

Automatic assessment of Alzheimer's disease diagnosis based on deep learning techniques

Early detection is crucial to prevent the progression of Alzheimer's disease (AD). Thus, specialists can begin preventive treatment as soon as possible. They demand fast and precise assessment in the diagnosis of AD in the earliest and hardest to detect stages. The main objective of this work is to develop a system that automatically detects the presence of the disease in sagittal magnetic resonance images (MRI), which are not generally used. Sagittal MRIs from ADNI and OASIS data sets were employed. Experiments were conducted using Transfer Learning (TL) techniques in order to achieve more accurate results. There are two main conclusions to be drawn from this work: first, the damages related to AD and its stages can be distinguished in sagittal MRI and, second, the results obtained using DL models with sagittal MRIs are similar to the state-of-the-art, which uses the horizontal-plane MRI. Although sagittal-plane MRIs are not commonly used, this work proved that they were, at least, as effective as MRI from other planes at identifying AD in early stages. This could pave the way for further research. Finally, one should bear in mind that in certain fields, obtaining the examples for a data set can be very expensive. This study proved that DL models could be built in these fields, whereas TL is an essential tool for completing the task with fewer examples.

Asociación de obesidad y dislipidemia con el riesgo de progresión a deterioro cognitivo leve y demencia: revisión sistemática

Objetivo: evaluar si en la literatura científica se describe una relación entre obesidad y dislipidemia con progresión a deterioro cognitivo leve (DCL) y demencia en adultos mayores de 65 años.  Métodos: búsqueda en la literatura científica publicada en PubMed, EbscoHost, ScienceDirect ClinicalKey y Registro Cochrane entre 2009 y 2017, de estudios prospectivos de cohortes, casos y controles de sujetos adultos con diagnóstico de obesidad o dislipidemia y con valoraciones de la función cognitiva a través del tiempo, con el fin de determinar la incidencia de DCL y demencia, y su relación con los factores de riesgo mencionados. Resultados: la revisión sistemática arrojó un total de 13 artículos de alta calidad según SIGN que cumplieron con los criterios de selección. De estos 7 incluyen la obesidad como factor de riesgo y 6 la dislipidemia. En los diferentes artículos relacionados con obesidad en adultos mayores no existió relación directa entre obesidad y deterioro cognitivo, de igual forma en los relacionados con dislipidemia no se reportó relación directa con   deterioro cognitivo. Conclusión: los pacientes adultos mayores con obesidad podrían tener un factor protector frente al desarrollo de deterioro cognoscitivo, lo que no ocurre con adultos jóvenes. Por su parte, la fisiopatología descrita en la dislipidemia sugiere que el colesterol alto o bajo pueden llevar a DCL y a demencia. 

Progress and perspectives of brain-targeting lipid-based nanosystems via the nasal route in Alzheimer's disease

Since health care systems dedicate substantial resources to Alzheimer's disease (AD), it poses an increasing challenge to scientists and health care providers worldwide, especially that many decades of research in the medical field revealed no optimal effective treatment for this disease. The intranasal administration route seems to be a preferable route of anti-AD drug delivery over the oral one as it demonstrates an ability to overcome the related obstacles reflected in low bioavailability, limited brain exposure and undesired pharmacokinetics or side effects. This delivery route can bypass the systemic circulation through the intraneuronal and extraneuronal pathways, providing truly needleless and direct brain drug delivery of the therapeutics due to its large surface area, porous endothelial membrane, the avoidance of the first-pass metabolism, and ready accessibility. Among the different nano-carrier systems developed, lipid-based nanosystems have become increasingly popular and have proven to be effective in managing the common symptoms of AD when administered via the nose-to-brain delivery route, which provides an answer to circumventing the BBB. The design of such lipid-based nanocarriers could be challenging since many factors can contribute to the quality of the final product. Hence, according to the authors, it is recommended to follow the quality by design methodology from the early stage of development to ensure high product quality while saving efforts and costs. This review article aims to draw attention to the up-to-date findings in the field of lipid-based nanosystems and the potential role of developing such forms in the management of AD by means of the nose-to-brain delivery route, in addition to highlighting the significant role of applying QbD methodology in this development.

Sex-associated differences in mitochondrial function in human peripheral blood mononuclear cells (PBMCs) and brain

BACKGROUND

Alzheimer's disease (AD) is the most common form of dementia, and it affects more women than men. Mitochondrial dysfunction (MD) plays a key role in AD, and it is detectable at an early stage of the degenerative process in peripheral tissues, such as peripheral mononuclear blood cells (PBMCs). However, whether these changes are also reflected in cerebral energy metabolism and whether sex-specific differences in mitochondrial function occur are not clear. Therefore, we estimated the correlation between mitochondrial function in PBMCs and brain energy metabolites and examined sex-specific differences in healthy participants to elucidate these issues.

METHODS

The current pilot study included 9 male and 15 female healthy adults (mean age 30.8 ± 7.1 years). Respiration and activity of mitochondrial respiratory complexes were measured using a Clarke-electrode (Oxygraph-2k system), and adenosine triphosphate (ATP) levels were determined using a bioluminescence-based assay in isolated PBMCs. Citrate synthase activity as a mitochondrial marker was measured using a photometric assay. Concentrations of brain energy metabolites were quantified in the same individuals using 1H-magnetic resonance spectroscopy (MRS).

RESULTS

We detected sex-associated differences in mitochondrial function. Mitochondrial complexes I, I+II, and IV and uncoupled respiration and electron transport system (ETS) capacity in PBMCs isolated from blood samples of females were significantly (p < 0.05; p < 0.01) higher compared to males. ATP levels in the PBMCs of female participants were approximately 10% higher compared to males. Citrate synthase (CS) activity, a marker of mitochondrial content, was significantly (p < 0.05) higher in females compared to males. Sex-associated differences were also found for brain metabolites. The N-acetylaspartate (NAA) concentration was significantly higher in female participants compared to males in targeted regions. This difference was observed in white matter (WM) and an area with a high percentage (> 50%) of gray matter (GM) (p < 0.05; p < 0.01). The effect sizes indicated a strong influence of sex on these parameters. Sex-associated differences were found in PBMCs and brain, but the determined parameters were not significantly correlated.

CONCLUSIONS

Our study revealed sex-associated differences in mitochondrial function in healthy participants. The underlying mechanisms must be elucidated in more detail, but our study suggests that mitochondrial function in PBMCs is a feasible surrogate marker to detect differences in mitochondrial function and energy metabolism in humans and it underscores the necessity of sex-specific approaches in therapies that target mitochondrial dysfunction.

A Novel Association of Polymorphism in the ITGA4 Gene Encoding the VLA-4 α4 Subunit with Increased Risk of Alzheimer's Disease

Alzheimer's disease (AD) is the most prevalent cause of dementia in elderly people worldwide. Many studies support the hypothesis that the inflammation of the CNS contributes to the neurodegeneration and disease progression. The integrin molecule α4β1, also known as very late antigen 4 (VLA-4), belongs to adhesion molecules that activate the inflammatory process through the migration of immune cells into the CNS. Therefore, the objective of our study was to analyze the association between two polymorphisms located in the ITGA4 gene encoding the α4 subunit of VLA-4 and the risk of AD. 104 late-onset AD patients and 206 control subjects from Slovakia were genotyped for ITGA4 gene SNP polymorphism rs113276800 (-269C/A) and rs1143676 (+3061A/G). The same study cohorts were also genotyped for the APOE-ε4, which is a known genetic factor associated with increased risk of AD developing. ITGA4 polymorphism analysis revealed significantly higher frequency of the +3061AG carriers in AD group compared to the controls (P ≤ 0.05). Following the APOE-ε4 stratification of study groups, the association remained significant only in APOE-ε4 noncarriers. Our study suggests a novel association of ITGA4 +3061A/G polymorphism with AD and its possible contribution to the disease pathology.