Machine and deep learning algorithms for classifying different types of dementia: A literature review.

The cognitive impairment known as dementia affects millions of individuals throughout the globe. The use of machine learning (ML) and deep learning (DL) algorithms has shown great promise as a means of early identification and treatment of dementia. Dementias such as Alzheimer's Dementia, frontotemporal dementia, Lewy body dementia, and vascular dementia are all discussed in this article, along with a literature review on using ML algorithms in their diagnosis. Different ML algorithms, such as support vector machines, artificial neural networks, decision trees, and random forests, are compared and contrasted, along with their benefits and drawbacks. As discussed in this article, accurate ML models may be achieved by carefully considering feature selection and data preparation. We also discuss how ML algorithms can predict disease progression and patient responses to therapy. However, overreliance on ML and DL technologies should be avoided without further proof. It's important to note that these technologies are meant to assist in diagnosis but should not be used as the sole criteria for a final diagnosis. The research implies that ML algorithms may help increase the precision with which dementia is diagnosed, especially in its early stages. The efficacy of ML and DL algorithms in clinical contexts must be verified, and ethical issues around the use of personal data must be addressed, but this requires more study.

Exploring the causal role of immune cells in vascular dementia: A bidirectional mendelian randomization study.

BACKGROUND: The aim of this study was to explore the causal association between immune cells and VaD based on a two-sample bidirectional Mendelian randomization study. METHODS: Bidirectional two-sample MR analyses based on pooled datasets from publicly available genome-wide association studies were performed using inverse variance weighted (IVW), weighted median (WE), and MR-Egger regressions to evaluate the causal relationships between immune cells and vascular dementia. Heterogeneity was assessed using Cochran's Q statistic. The reliability of the MR analysis results was verified by using the MR-PRESSO method for outlier detection, the MR-Egger method for horizontal multivariate analysis, and the leave-one-out method for sensitivity analysis. RESULTS: Specifically, 27 immunophenotypes were associated with VaD pathogenesis, including Sw mem %lymphocyte (P = 0.043), CD38 on CD20- (P = 0.039), CD11c+ monocyte AC (P = 0.024), DC AC (P = 0.002), CCR2 on CD62L+ myeloid DC (P = 0.039), Resting Treg %CD4 (P = 0.042), Activated & resting Treg %CD4+ (P = 0.038), CD28+ CD45RA- CD8br %CD8br (P = 0.047), NK %CD3- lymphocyte (P = 0.042), CD45 on B cell (P = 0.029), FSC-A on NKT (P = 0.033), CD45 on CD33br HLA DR+ CD14- (P = 0.039) were significantly correlated with increased VaD risk. Additionally, four immune phenotypes, namely, CD19 on CD20-, Resting Treg %CD4, Activated & resting Treg %CD4+, and CD11c+ monocyte AC, showed bidirectional effects on VaD. CONCLUSIONS: MR analysis revealed potential causal relationships between certain immune cells and VaD. Our preliminary exploration through immune cell infiltration analysis highlights the significant value of immune cells in VaD. Therefore, this study may provide a new perspective for the prevention and treatment of VaD.

Should dietary restrictions be imposed on Alzheimer's Disease patients affected by type 2 diabetes?

INTRODUCTION: Antidiabetic drugs, reduction of carbohydrates intake, maintaining normal weight and physical activity are the cornerstone of diabetes 2 treatment. METHODS: This opinion article is not intended to challenge hundreds of studies unequivocally demonstrating the benefits of a healthy lifestyle including appropriate diet in controlling the consequences of T2DM. The article questions whether the benefits of dietary restrictions for the management of T2D in older adults who are already demented, are worth the potential detrimental effects on quality of life for the patients and their caregivers, as well as the effects of dietary restrictions on frailty, sarcopenia. DISCUSSION: However, the benefit of dietary restrictions including carbohydrates restrictions, might not manifest in elderly Alzheimer and vascular dementia patients with type 2 diabetes. On the contrary, such restrictions might hinder the patients' and caregiver's quality of life and encumber attempts to maintain normal weight in a population which tends to be underweight. Therefore, the benefit/risk ratio of dietary restriction should be weighed in this population on an individual basis.

Inhibition of histone methyltransferase promotes cognition and mitochondrial function in vascular dementia model.

Vascular dementia (VD) is one of the most common forms of dementia worldwide, characterized by problems with reasoning, planning, judgment, and memory. This study investigated the effect of a histone methyltransferase inhibitor on cognition and mitochondrial function in a rat model of VD, as well as its impact on H2O2-induced neurotoxicity in hippocampal neuronal cultures. In the in vivo experiments, VD was induced by bilateral occlusion of the common carotid artery (CCA) for one month. The histone methyltransferase inhibitor, BIX01294, was administered intracerebroventricularly for one month (22.5 µg.kg-1 three times/week). On day 30, behavioral tests, including the novel object recognition test and elevated plus maze test, were conducted. Mitochondrial enzyme activities, including aconitase, α-ketoglutarate dehydrogenase (α-KG), complex I, and complex IV, were evaluated in the hippocampus of rats following CCA ligation. In the in vitro experiments, the effect of BIX01294 (50-600 µM) on H2O2 (400 µM)-induced cytotoxicity in hippocampal neuronal cells was assessed using the MTT assay. Flow cytometry was performed to evaluate apoptosis. Our findings revealed that BIX01294 effectively improved memory function, Krebs cycle enzyme activity, and mitochondrial function in the rat model of VD. Moreover, in vitro results showed that BIX01294 at a concentration of 100 µM significantly reversed the cytotoxicity and apoptosis induced by H2O2 in neuronal cells. These findings suggest that BIX01294 may have the potential to improve VD complications by reducing oxidative stress and inhibiting histone methylation.

Risk of Dementia in Different Types of Cancer Survivors: A Nationwide Cohort Study.

OBJECTIVES: The association between specific types of malignancies and the subsequent risk of dementia remains unknown. DESIGN: A retrospective population-based cohort study based on data from Taiwan National Health Insurance Research Database. SETTING AND PARTICIPANTS: We recruited 32,250 patients who survived malignancies and 322,500 controls between 1998 and 2011 and followed them up until the end of 2013. MEASUREMENTS: Diagnoses of dementia (including Alzheimer's disease (AD), vascular dementia (VaD), and unspecified dementia) was made during the follow-up period. Cox regression analyses were performed after adjusting for potential confounders. A sensitivity analysis was conducted to exclude patients with prodromal dementia. RESULTS: Cancer survivors were more likely to develop AD (hazard ratio [HR]: 1.68, 95% confidence interval [CI]: 1.38-2.06), unspecified dementia (HR: 1.19, 95% CI: 1.07-1.32), and any dementia (HR: 1.26, 95% CI: 1.16-1.37) compared with controls after adjusting for potential confounders. Importantly, cancers of the digestive and genitourinary organs seem to be associated with AD, unspecified dementia, and any dementia, whereas only malignant neoplasms of the brain are more likely to develop into VaD. Sensitivity analyses after exclusion of the first three or five years of observation and after exclusion of case enrollment before 2009 or 2007 showed consistent findings. CONCLUSION: Cancer survivors are at higher risk of subsequent dementia. Different types of cancer survivors may contribute to variable risks of specific dementias. Further studies are necessary to investigate the underlying mechanisms in cancer survivors and patients with dementia.

Clinical application of whole genome sequencing in young onset dementia: challenges and opportunities.

INTRODUCTION: Young onset dementia (YOD) by its nature is difficult to diagnose. Despite involvement of multidisciplinary neurogenetics services, patients with YOD and their families face significant diagnostic delays. Genetic testing for people with YOD currently involves a staggered, iterative approach. There is currently no optimal single genetic investigation that simultaneously identifies the different genetic variants resulting in YOD. AREAS COVERED: This review discusses the advances in clinical genomic testing for people with YOD. Whole genome sequencing (WGS) can be employed as a 'one stop shop' genomic test for YOD. In addition to single nucleotide variants, WGS can reliably detect structural variants, short tandem repeat expansions, mitochondrial genetic variants as well as capture single nucleotide polymorphisms for the calculation of polygenic risk scores. EXPERT OPINION: WGS, when used as the initial genetic test, can enhance the likelihood of a precision diagnosis and curtail the time taken to reach this. Finding a clinical diagnosis using WGS can reduce invasive and expensive investigations and could be cost effective. These advances need to be balanced against the limitations of the technology and the genetic counseling needs for these vulnerable patients and their families.

Efficacy of 5 and 10 mg donepezil in improving cognitive function in patients with dementia: a systematic review and meta-analysis.

Objective: The purpose of this study was to compare donepezil at 5 mg and 10 mg/day against a placebo to systematically evaluate its effectiveness in improving cognitive function among patients suffering from dementia at any stage. Method: For this systematic review and meta-analysis, we looked up Medline, Scopus, Embase, Web of Science, and The Cochrane Library for articles on the efficacy of donepezil in dementia published in the past 20 years and summarized the placebo and intervention data. Initially, a total of 2,272 articles were extracted using our search query and after the inclusion and exclusion criteria set for extraction of data, 18 studies were included in this review using PRISMA flowchart. The ADAS-cog and MMSE assessment scales were used for measuring the outcomes using IBM SPSS 29.0 for the meta-analysis. Result: The meta-analysis comprised a total of 18 RCTs (randomized controlled trials) that were randomized to receive either donepezil 5 mg/day (n = 1,556), 10 mg/day (n = 2050) or placebo (n = 2,342). Meta-analysis concerning efficacy showed that donepezil at 10 mg/day significantly improved the MMSE score (g: 2.27, 95%CI: 1.25-3.29) but could not substantially reduce the ADAS-cog. At 5 mg/day donepezil, an overall slight improvement in MMSE score (Hedges' g: 2.09, 95%CI: 0.88-3.30) was observed. Conclusion: Both donepezil 5 mg/day and 10 mg/day doses demonstrated improved cognitive functions for patients with dementia, however results indicated that the 10 mg/day dose was more efficacious.

Effect of Different Durations of Treatment With Antihypertensive Drugs With Anticholinergic Effects on the Risk of Dementia: A Target Trial Emulation Study.

Studying the effect of duration of treatment on prognostic outcomes using real-world data is challenging because only people who survive for a long time can receive a treatment for a long time. Specifying a target trial helps overcome such challenge. We aimed to estimate the effect of different durations of treatment with antihypertensive drugs with anticholinergic properties (AC AHT) on the risk of vascular dementia and Alzheimer's disease by emulating a target trial using the UK CPRD GOLD database (2001-2017). Comparing treatment for 3-6 years versus ≤3 years yielded null results for both types of dementia. Comparing a longer duration of treatment, >6 years versus ≤3 years, yielded a 10-year risk ratio of 0.69 (95% CI, 0.54-0.90) for vascular dementia and 0.91 (95% CI, 0.77-1.10) for Alzheimer's disease. For illustration, we performed an analysis that failed to emulate a target trial by assigning exposure categories using post-baseline information, obtaining implausible beneficial estimates. Our findings indicate a modest benefit of longer duration of treatment with AC AHT on vascular dementia and highlight the value of the target trial emulation to avoid selection bias in the evaluation of the effect of different durations of treatment.

The association between urinary sodium and the risk of dementia: Evidence from a population-based cohort study.

BACKGROUND: Sodium intake reduction is crucial for cardiovascular health, however, its lasting impact on dementia remains unclear. METHODS: We included 458,577 UK Biobank participants without dementia at baseline. We estimated 24-h urinary sodium (E24hUNa) using spot urinary parameters and obtained the incidence of all-cause dementia, Alzheimer's disease, and vascular dementia from multiple sources. RESULTS: The mean E24hUNa was 3.0 g (1st-99th percentile: 1.5 g-5.1 g). Over a mean follow-up of 13.6 years, 7886 (1.7 %) participants developed all-cause dementia, including 3763 (0.8 %) Alzheimer's disease and 1851 (0.4 %) vascular dementia. In the restricted cubic spline model, we identify a potential cutoff of 3.13 g for E24hUNa, below which each 1 g decrease in E24hUNa was associated with 21 % (95 % confidence interval [CI] 1.11-1.34) higher all-cause dementia risk and 35 % (95 % CI 1.11-1.63) higher vascular dementia risk (P-value <0.001 for non-linearity). The hazard ratios were 1.15 (95 % CI, 1.07-1.24) for all-cause dementia and 1.21 (95 % CI 1.04-1.40) for vascular dementia among individuals with E24hUNa below 3.13 g compared to those with E24hUNa higher than 3.13 g. LIMITATIONS: One of the major limitations is the estimation of 24-h urinary sodium with spot urine samples. CONCLUSIONS: An E24hUNa level below 3.13 g, equivalent to 3.37 g daily sodium intake, is associated with increased risks of all-cause and vascular dementia. This exploratory study suggests a potential lower limit below which the risk of dementia increases with a lower sodium level. Future studies are necessary to validate our findings.

COVID-19 outcomes among patients with dementia and age-matched controls who were hospitalized in 21 US health-care systems.

INTRODUCTION: COVID-19 had devastating impacts worldwide. However, most research examining the impact of dementia on COVID-19 outcomes has been conducted in Europe and Asia and has not examined dementia subtypes. METHODS: A retrospective analysis of electronic health record data from 21 US health-care systems examined relationships of all-cause dementia, Alzheimer's disease (AD), and vascular dementia with in-hospital mortality, intensive care unit (ICU) admission, and hospital stay duration. RESULTS: All-cause dementia, but not AD or vascular dementia independently, was associated with increased mortality risk, the inclusion of discharge to hospice as a mortality equivalent increased risk for mortality for all-cause dementia, and AD and vascular dementia. Patients with all-cause dementia and AD were less likely to be admitted to the ICU than patients without. Patients with any form of dementia had longer hospital stays than patients without. DISCUSSION: Dementia was associated with increased mortality or hospice discharge, decreased ICU admissions, and longer hospital stays. HIGHLIGHTS: Only all-cause dementia was associated with increased mortality risk. This risk was lower than what has been published in previous research. Combining mortality and hospice discharge increased risk for all dementia subtypes. All-cause and Alzheimer's disease (AD) dementia were associated with decreased intensive care unit admissions. All-cause, vascular, and AD dementia were associated with longer hospital stays.

Efficacy and safety of ginkgo biloba extract combined with donepezil hydrochloride in the treatment of Chinese patients with vascular dementia: A systematic review meta-analysis.

Objective: To conduct a meta-analysis of the effectiveness and safety of ginkgo biloba extract combined with donepezil hydrochloride vs. donepezil for the treatment of vascular dementia (VaD). Methods: Four English databases (PubMed, EMBASE, Web of Science, Cochrane Library) and four Chinese databases [the China National Knowledge Infrastructure Wanfang DATA, the Chongqing VIP Database (VIP), China Biomedical Database (CBM)] were manually searched for literature published from dates of the inception of the databases to September 2023. The randomized controlled trials (RCTs) of ginkgo biloba extract with donepezil hydrochloride vs. donepezil for the treatment of VaD were included. Relevant literature was screened, and the data in the included studies were extracted for quality assessment according to the Risk of bias tool. Results: A total of 1,309 participants were enrolled in the 15 RCTs. Of these, 656 participants were in the experimental group (ginkgo biloba extract combined with donepezil) and 653 participants were in the control group (donepezil).The results showed that combination therapy was superior to donepezil alone, and there were statistically significant differences in several outcomes including RR in change for total effective rate (1.28, 95% confidence intervals 1.20, 1.38, p < 0.001), MD in change for Mini-Mental State Examination score (2.98, 95%CI 2.31, 3.65, p < 0.001), Barthel Index score (8.55,95%CI 1.11, 15.99, p = 0.024), Activity of Daily Living Scale (ADL)score (10.11,95% CI 7.16,13.07,p < 0.001). Conclusion: Ginkgo biloba extract combined with donepezil dramatically improved the total effective rate, MMSE, BI and ADL scores, and decreased homocysteine (HCY), plasma viscosity (PV), whole blood viscosity at high cut (BVH) and whole blood viscosity at low cut (BVL) in VaD patients, while the effect on mean flow velocity and pulse index (PI) of middle cerebral artery (MCA) is not obvious. However, more relevant high-quality RCTs are needed to validate these results. Systematic Review Registration: Identifier CRD42023474678.

Apelin Receptor Homodimerisation Inhibits Hippocampal Neuronal Autophagy via G Protein-Dependent Signalling in Vascular Dementia.

Vascular dementia (VD), a progressive vascular cognitive impairment, is characterised by the presence of cerebral hypoperfusion, increased blood-brain barrier permeability, and white matter lesions. Although current treatment strategies primarily focus on risk factors such as hypertension, diabetes, and heart disease, efficient and targeted therapies are lacking and the underlying mechanisms of VD remain unclear. We previously discovered that Apelin receptors (APJ), which are G protein-coupled receptors (GPCRs), can homodimerize and generate signals that are distinct from those of APJ monomers in VD rats. Apelin-13 reduces the level of APJ homodimers and leads to the proliferation of endogenous neural stem cells in the hippocampal dentate gyrus area, suggesting that it has a neuroprotective role. In this study, we established a rat and cellular oxygen-glucose deprivation/reoxygenation VD model to investigate the impact of APJ homodimerisation on autophagy. We found that APJ homodimers protect against VD by inhibiting autophagy through the Gαq and PI3K/Akt/mTOR pathways upon Gαi signalling, both in vivo and in vitro. This discovery provides a promising therapeutic target for chronic cerebral ischaemia-reperfusion diseases and an experimental foundation for the development of drugs that target APJ homodimers.

Dementia incidence varied by anticancer drugs and molecular targeted therapy in a population-based cohort study.

Anticancer drugs may affect the incidence of dementia by modulating the common pathophysiology between cancer and dementia. However, there is a paucity of research that focused on anticancer drugs with different mechanisms of action and their associations with subtypes of dementia. Therefore, we aimed to investigate the incidence of dementia according to various groups of anticancer drugs. From the Korea National Health Insurance Service database, our retrospective population-based cohort study enrolled 116,506 cancer patients aged 65 years and older who received anticancer drugs between January 1, 2008 and December 31, 2018. The hazard ratio was determined using Cox proportional hazards regression models, comparing each group of anticancer drugs to all other anticancer drugs, after adjusting for covariates. Antimetabolites (HR = 0.91; 95% CI 0.84-0.97) and molecular targeted therapies (HR = 0.60; 95% CI 0.49-0.74) were associated with a decreased incidence of dementia of the Alzheimer type (DAT), but not with vascular dementia. Among molecular targeted therapies, epidermal growth factor receptor inhibitors (HR = 0.60; 95% CI 0.46-0.79) and multikinase inhibitors (HR = 0.49; 95% CI 0.27-0.89) were associated with a low incidence of DAT only. Our findings highlight the potential for targeted repurposing of anticancer drugs to prevent dementia.

A genome-wide association meta-analysis of all-cause and vascular dementia.

INTRODUCTION: Dementia is a multifactorial disease with Alzheimer's disease (AD) and vascular dementia (VaD) pathologies making the largest contributions. Yet, most genome-wide association studies (GWAS) focus on AD. METHODS: We conducted a GWAS of all-cause dementia (ACD) and examined the genetic overlap with VaD. Our dataset includes 800,597 individuals, with 46,902 and 8702 cases of ACD and VaD, respectively. Known AD loci for ACD and VaD were replicated. Bioinformatic analyses prioritized genes that are likely functionally relevant and shared with closely related traits and risk factors. RESULTS: For ACD, novel loci identified were associated with energy transport (SEMA4D), neuronal excitability (ANO3), amyloid deposition in the brain (RBFOX1), and magnetic resonance imaging markers of small vessel disease (SVD; HBEGF). Novel VaD loci were associated with hypertension, diabetes, and neuron maintenance (SPRY2, FOXA2, AJAP1, and PSMA3). DISCUSSION: Our study identified genetic risks underlying ACD, demonstrating overlap with neurodegenerative processes, vascular risk factors, and cerebral SVD. HIGHLIGHTS: We conducted the largest genome-wide association study of all-cause dementia (ACD) and vascular dementia (VaD). Known genetic variants associated with AD were replicated for ACD and VaD. Functional analyses identified novel loci for ACD and VaD. Genetic risks of ACD overlapped with neurodegeneration, vascular risk factors, and cerebral small vessel disease.

Cardiovascular risk factors are associated with cognitive trajectory in the first year after stroke.

Introduction: Stroke often leads to cognitive impairment, but its progression and influencing factors over time remain poorly understood. This study evaluates immediate post-stroke cognitive impacts and investigates the influence of concurrent factors on cognitive evolution over the first year. Patients and methods: In the STRATEGIC study, 179 patients with first symptomatic ischemic stroke underwent neuropsychological assessments within three months post-stroke, and 141 were re-evaluated at 12 months. Risk factors tested for associations with cognitive outcome included demographic variables, cardiovascular and other medical factors, and lesion characteristics. Cognitive performance was primarily measured via the Montreal Cognitive Assessment (MoCA), with domain-specific assessments for episodic memory (Free and Cued Selective Reminding Task), short-term memory (Digit Span forward), and working memory (Digit Span backward). Results: At the time of stroke, participants ranged in age from 46 to 89 years (M = 70, SD = 9.5) and 36.9% were female. Ischemic heart disease predicted cognitive non-improvement between 3 and 12 months. Atrial fibrillation and carotid stenosis were linked to changes in episodic and working memory, respectively. Moreover, female sex and lower education correlated with stagnant global cognition and episodic memory. Discussion and conclusion: Our findings underscore the important influence of cardiovascular risk factors on cognitive functional recovery after stroke. Interventions targeting these risk factors may improve cognitive prognosis and affect traditional outcome measures such as recurrent vascular events. Future trials should include cognitive measures to fully capture the potential benefits of intensive risk factor intervention.

[Mechanism of electroacupuncture for vascular dementia based on proteomics].

OBJECTIVE: To explore the potential mechanism of electroacupuncture (EA) for vascular dementia (VD) using tandem mass tag (TMT) quantitative proteomics technology. METHODS: Among 80 male SPF SD rats, 78 rats which met the selection criteria through the Morris water maze test were selected and randomly divided into a sham surgery group (18 rats) and a surgery group (60 rats). VD model was established by four-vessel occlusion (4-VO) method in the surgery group, and 36 rats with successful modeling were randomly assigned to a model group (18 rats) and an EA group (18 rats). Each group was further divided into three subgroups based on intervention duration, with each subgroup containing 6 rats. Seven days after model establishment, the EA group received EA intervention at left and right "Sishencong" (EX-HN 1) and bilateral "Fengchi" (GB 20), with continuous wave at a frequency of 2 Hz and current intensity of 1 mA, daily for 30 min, with subgroups receiving EA for 7, 14, or 21 d respectively. Cognitive function before and after interventions was assessed using Morris water maze. Proteomic analysis was conducted on the optimal EA subgroup and corresponding sham surgery and model subgroups, identifying differentially expressed proteins and analyzing them through bioinformatics. Differentially expressed target proteins was performed using parallel reaction monitoring (PRM) and Western blot techniques. RESULTS: Compared to the sham surgery group, the model group exhibited prolonged escape latency and reduced number of platform crossings (P<0.01); compared with model group, the EA group showed reductions in escape latency and increased platform crossings after 7, 14, and 21 days of intervention (P<0.01, P<0.05). Compared to the 7 and 14-day intervention, the rats in the EA group of 21-day intervention showed the most significant improvements in reductions of escape latency and increased platform crossings (P<0.01, P<0.05), and was selected for further proteomic, PRM analyses, and Western blot validation. Compared to the sham surgery group, the model group displayed 71 differentially expressed proteins, with 50 up-regulated and 21 down-regulated proteins; compared to the model group, the EA group had 54 differentially expressed proteins, with 30 up-regulated and 24 down-regulated proteins. Functional enrichment and clustering analyses indicated that these proteins were primarily associated with cellular processes, metabolic processes, phagocytosis recognition, immune response, and regulation of extracellular matrix, etc. Enrichment was observed in the mammalian target of rapamycin (mTOR) signaling pathway and neurotrophic factors signaling pathways, involving glycogen synthase kinase 3ß (GSK3ß) and mitogen-activated protein kinase kinase 2 (Map2k2), with PRM and Western blot findings consistent with the proteomic results. Which meant that compared with the model group, the protein expression of GSK3ß and Map2k2 of hippocampus was increased in the EA group (P<0.01, P<0.05). CONCLUSION: EA at "Sishencong" (EX-HN 1) and "Fengchi" (GB 20) could improve cognitive function in VD rats, with the mechanism involving multiple targets and pathways, potentially related to GSK3ß, Map2k2 proteins, and the mTOR and neurotrophic factor signaling pathways.

Pseudoginsenoside-F11 reduces cognitive impairment and white matter injury in vascular dementia by alleviating autophagy-lysosomal pathway deficiency.

BACKGROUND: Vascular dementia (VaD) resulting from chronic cerebral hypoperfusion (CCH) induces cognitive impairment and white matter injury (WMI). We previously found that CCH induces dysfunction of the autophagy-lysosomal pathway (ALP) in white matter (WM) of rats. Enhancing oligodendrocyte autophagy to counteract ALP deficiency is beneficial for cognitive recovery. Pseudogenoside-F11 (PF11), a saponin extracted from Panax quinquefolium l., provides neuroprotective benefits in many animal models of cerebral ischemia and dementia. PURPOSE: To investigate how PF11 affects cognitive deterioration in rats with VaD induced by two vessel occlusion (2VO), and to determine if PF11 regulates ALP dysfunction in WM. METHODS: CCH-related VaD was induced in rats using the 2VO method. PF11 (6, 12, 24 mg/kg, intragastric administration) was given continuously for 4 weeks postoperatively. Behavioral tests related to cognitive function were performed on the 28th day following 2VO. Transmission electron microscopy, immunofluorescence, western blotting and Luxol fast blue staining were used to assess the WMI and the mechanism of action of PF11 in 2VO-induced VaD. RESULTS: PF11 (12 mg/kg) ameliorated 2VO-induced cognitive impairment. PF11 also alleviated WMI on the 28th day following 2VO, as characterized by reduction of neuronal axonal demyelination and axonal loss. Furthermore, PF11 prevented mature oligodendrocytes death by attenuating ALP deficiency in WM on the 14th day following 2VO, as manifested by enhancement of mechanistic target of rapamycin-mediated autophagy and lysosomal function, thereby reducing the aberrant accumulation of autophagy substrates and increasing the level of autophagosomes in WM. In addition, PF11 also prevented microglia and astrocytes from activating in WM on the 28th day following 2VO. CONCLUSION: PF11 significantly ameliorates cognitive impairment and WMI, and the mechanism is at least partly related to lessening ALP dysfunction in WM by enhancing autophagy and reducing lysosomal defects in oligodendrocytes.

Cerebrovascular lesion loads and accelerated brain aging: insights into the cognitive spectrum.

Introduction: White matter hyperintensities (WMHs) and cerebral microbleeds are widespread among aging population and linked with cognitive deficits in mild cognitive impairment (MCI), vascular MCI (V-MCI), and Alzheimer's disease without (AD) or with a vascular component (V-AD). In this study, we aimed to investigate the association between brain age, which reflects global brain health, and cerebrovascular lesion load in the context of pathological aging in diverse forms of clinically-defined neurodegenerative conditions. Methods: We computed brain-predicted age difference (brain-PAD: predicted brain age minus chronological age) in the Comprehensive Assessment of Neurodegeneration and Dementia cohort of the Canadian Consortium on Neurodegeneration in Aging including 70 cognitively intact elderly (CIE), 173 MCI, 88 V-MCI, 50 AD, and 47 V-AD using T1-weighted magnetic resonance imaging (MRI) scans. We used a well-established automated methodology that leveraged fluid attenuated inversion recovery MRIs for precise quantification of WMH burden. Additionally, cerebral microbleeds were detected utilizing a validated segmentation tool based on the ResNet50 network, utilizing routine T1-weighted, T2-weighted, and T2* MRI scans. Results: The mean brain-PAD in the CIE cohort was around zero, whereas the four categories showed a significantly higher mean brain-PAD compared to CIE, except MCI group. A notable association trend between brain-PAD and WMH loads was observed in aging and across the spectrum of cognitive impairment due to AD, but not between brain-PAD and microbleed loads. Discussion: WMHs were associated with faster brain aging and should be considered as a risk factor which imperils brain health in aging and exacerbate brain abnormalities in the context of neurodegeneration of presumed AD origin. Our findings underscore the significance of novel research endeavors aimed at elucidating the etiology, prevention, and treatment of WMH in the area of brain aging.