Memory loss in Alzheimer's disease

A study to determine the effect of nano-selenium and thymoquinone on the Nrf2 gene expression in Alzheimer's disease

INTRODUCTION

Alzheimer's disease is a developing public health concern in aging communities that affects a sizable section of the global population. The risk of Alzheimer's disease increases with age; it affects one-third of males and two-thirds of women. This research attempts to assess the effect of nano-selenium and thymoquinone on Nrf2 gene expression levels in Alzheimer's disease (AD).

METHODS

There were five identical groups of 50 albino male rats: a control group that was healthy; an AD positive control group; an AD group that received nano-selenium (5 mg/kg); an AD group that received thymoquinone (2 mg/kg); and an AD group that received both. The duration of treatment was 4 weeks. The levels of Nrf2 in brain tissues were evaluated using real-time PCR.

RESULTS

Nrf2 mean expression levels in the nano-selenium-treated rats, the thymoquinone-treated rats, and the rats that were given both treatments all increased significantly compared to AD rats with no treatment.

CONCLUSIONS

This study showed that nano-selenium and thymoquinone elevated Nrf2 gene expression levels in AD.

Online Communities as a Support System for Alzheimer Disease and Dementia Care: Large-Scale Exploratory Study

BACKGROUND

Alzheimer disease (AD) is the leading type of dementia, demanding comprehensive understanding and intervention strategies. In the United States, where over 6 million people are impacted, the prevalence of AD and related dementias (AD/ADRD) presents a growing public health challenge. However, individuals living with AD/ADRD and their caregivers frequently express feelings of marginalization, describing interactions characterized by perceptions of patient infantilization and a lack of respect.

OBJECTIVE

This study aimed to address 2 key research questions (RQs). For RQ1, we investigated the needs and concerns expressed by participants in online social communities focused on AD/ADRD, specifically on 2 platforms-Reddit's r/Alzheimers and ALZConnected. For RQ2, we examined the prevalence and distribution of social support corresponding to these needs and concerns, and the association between these needs and received support.

METHODS

We collected 13,429 posts and comments from the r/Alzheimers subreddit spanning July 2014 to November 2023, and 90,113 posts and comments from ALZConnected between December 2020 (the community's earliest post) and November 2023. We conducted topic modeling using latent Dirichlet allocation (LDA), followed by labeling to identify the major topical themes of discussions. We used transfer learning classifiers to identify the occurrences of emotional support (ES) and informational support (IS) in the comments (or responses) in the discussions. We built regression models to examine how various topical themes are associated with the kinds of support received.

RESULTS

Our analysis revealed a diverse range of topics reflecting community members' varying needs and concerns of individuals affected by AD/ADRD. These themes encapsulate the primary discussions within the online communities: memory care, nursing and caregiving, gratitude and acknowledgment, and legal and financial considerations. Our findings indicated a higher prevalence of IS compared to ES. Regression models revealed that ES primarily occurs in posts relating to nursing and caring, and IS primarily occurs in posts concerning medical conditions and diagnosis, legal and financial, and caregiving at home.

CONCLUSIONS

This study reveals that online communities dedicated to AD/ADRD support engage in discussions on a wide range of topics, such as memory care, nursing, caregiving, and legal and financial challenges. The findings shed light on the key pain points and concerns faced by individuals managing AD/ADRD in their households, revealing how they leverage online platforms for guidance and support. These insights underscore the need for targeted institutional and social interventions to address the specific needs of AD/ADRD patients, caregivers, and other family members.

Periodontitis Increases Gingival, Serum and Hippocampus β-Amyloid Expressions but Reduces Neurovascular Coupling in Basilar Artery of Rats

AIM

Neurodegenerative diseases are characterized by early increased beta-amyloid (Aβ) and decreased cerebrovascular reactivity. We investigated Aβ in gingiva, serum or hippocampus and neurovascular reactivity in basilar artery (BA) of periodontitis rats, to test the impact of Aβ on BA vasoreactivity ex vivo.

MATERIALS AND METHODS

Periodontitis was induced in 32 rats using silk-ligation. Rats were sacrificed at weeks 0, 1, 2 and 4. Gingival TNF-α, IL-1β and Aβ were quantified via immunoblotting. Alveolar bone destruction was examined by micro-computed tomography. Serum and hippocampus Aβ values were measured by enzyme-linked immunosorbent assay and fluorescence staining, respectively. Vasoreactivity was measured by myography on isolated BA.

RESULTS

From Week 1, gingival TNF-α and IL-1β and bone destruction increased. Gingiva, serum and hippocampus Aβ values increased from Week 2. Nicotine-induced BA relaxation declined from Week 2, while acetylcholine-induced relaxation decreased by Week 4. Bone loss correlated with Aβ and nicotine-induced relaxation. Correlations were observed between Aβs in tissues, between two induced BA relaxations and between Aβ expressions and the induced relaxations. Ex vivo, Aβ reduced nicotine- and isoproterenol-induced relaxations but not electrical stimulated relaxation.

CONCLUSIONS

Periodontitis may increase Aβ expressions and reduce BA neurovascular reactivity, with Aβ contributing to this abnormal neurovascular coupling.

Integrating network pharmacology and in vivo study to explore the anti-Alzheimer's potential of Bergenia ligulata and Nelumbo nucifera

Amyloid plaque buildup, tau protein tangles, oxidative stress, and neuronal death are the hallmarks of Alzheimer's disease (AD). Using network pharmacology, molecular docking, and in vivo experiments, this study investigated the neuroprotective potential of Bergenia ligulata (BL) and Nelumbo nucifera (NN) against aluminum chloride (AlCl₃)-induced AD. Network pharmacology focused on important biomarker proteins like acetylcholinesterase (AChE), BCL2, and caspase-3 to identify 74 bioactive targets linked to AD. The evaluation of ligand-protein interactions was done using molecular docking. Male Wistar rats were exposed to AlCl₃ to cause AD-like pathology in vivo, and a combination treatment of BL and NN at varying doses was provided. Apoptosis markers (BCL2, caspase-3), biochemical investigations (AChE activity, oxidative stress markers-GSH, SOD, catalase, and lipid peroxidation), behavioral evaluations (elevated plus maze, conditioned avoidance test), and histopathological analyses were investigated. The combination of BL and NN demonstrated substantial neuroprotection in a dose-dependent manner. Reduced AChE levels point out improved cholinergic activity. Oxidative stress indicators showed improvement, with lower levels of malondialdehyde and higher anti-oxidant levels of GSH, SOD, and catalase. Apoptotic markers showed an increase in BCL2 expression and a decrease in caspase-3, suggesting anti-apoptotic effects. Reduced neuronal degeneration in the cortex and hippocampal regions was confirmed by histopathology of the brain. The synergistic potential of BL and NN demonstrated potent neuroprotective effects by modulating AChE activity, reducing oxidative stress, increasing anti-oxidant levels, and inhibiting apoptosis. These findings highlighted the potential of BL and NN as a new therapeutic approach for the AD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-025-04274-w.

Crocin Improves Cognitive Impairment in LPS-treated Rats through Anti-Apoptotic, Anti-Inflammatory, and Antioxidant Activities

Brain inflammation and oxidative stress play critical roles in neuronal apoptosis and memory dysfunction in Alzheimer's disease. Crocin, a natural carotenoid in the stigma of saffron, possesses radical scavenging, anti-inflammatory, and anti-apoptotic properties. This study investigates the protective impact of crocin on neuronal apoptosis, oxidative stress, neuroinflammation, and memory deficits induced by lipopolysaccharide (LPS) in rats. Male Wistar rats received 100 mg/kg of crocin for 12 days, with LPS (1 mg/kg, ip) injected on days 8-12. Spatial learning and memory were evaluated in the Morris water maze two hours after LPS injection. Gene expression of nuclear factor kappa B (NF-κB), tumor necrosis factor-α (TNF-α), caspase 3, and lipid peroxidation was assessed in hippocampal homogenates at the end of the behavioral test. Histopathological changes in the hippocampus and cerebral cortex were evaluated using H&E staining. The results indicated that LPS administration caused spatial learning and memory dysfunction (P = 0.001, P < 0.01) accompanied by upregulation of Nfkb, Tnfα, and Casp3 mRNA expression (P < 0.0001), increased TNF-α (P < 0.01) and lipid peroxidation level (P < 0.01), decreased total thiol concentration (P < 0.05), tissue damage and neuronal loss in the hippocampus (P < 0.0001). Furthermore, crocin treatment at a dosage of 100 mg/kg attenuated learning and memory impairments (P = 0.001, P < 0.01), downregulated Nfkb, Tnfα, and Casp3 mRNA expression (P < 0.0001), decreased TNF-α level (P < 0.01) and lipid peroxidation (P < 0.05) and increased total thiol level (P < 0.05) in the hippocampus. Crocin also ameliorated LPS-induced pathological changes and neuronal loss in the hippocampus (P < 0.001) and cerebral cortex (P < 0.01). In conclusion, the neuroprotective effects of crocin against LPS-induced histopathological and behavioral changes could be attributed to its anti-apoptotic, anti-inflammatory, and radical-scavenging activities in the rat brain.

Development of a k-Nearest Neighbors Model for the Prediction of Late-Onset Alzheimer's Risk by Combining Polygenic Risk Scores and Phenotypic Variables

INTRODUCTION

Alzheimer's disease (AD), and more specifically late-onset Alzheimer's disease (LOAD), represents a considerable challenge in terms of early and timely diagnosis and treatment. Early diagnosis is crucial to improve the efficacy of the therapies and patients' quality of life. The current challenge is to accurately identify at-risk individuals before the manifestations of the first symptoms of AD.

METHODS AND RESULTS

Here, we present an improved model for LOAD risk prediction, which applies the k-nearest neighbors (KNN) algorithm. We have achieved a sensitivity of 0.80 and an area under the curve (AUC) of 0.71, which represents a high performance especially when compared to an AUC of 0.66 reported previously in 2019 using a KNN model.

DISCUSSION

The application of a mathematical model that combines genetic and clinical covariates showed a good prediction of the AD/LOAD risk, with the higher weight being the polygenic genetic risk, APOE haplotype, and age. Compared to previous studies, our model integrates and correlates genetic prediction together with phenotypic information by fine-tuning the parameters of the model in order to achieve the best performance. This algorithm can be used in the general population and does not require the manifestation of any symptoms for its effective application. Thus, we present here an advanced model for risk prediction of LOAD.

Synthesis, Molecular Simulation, DFT, and Kinetic Study of Imidazotriazole-Based Thiazolidinone as Dual Inhibitor of Acetylcholinesterase and Butyrylcholinesterase Enzymes

Background: Alzheimer's disease is a complex and multifactorial brain disorder characterized by gradual memory impairment, cognitive disturbance, and severe dementia, and, ultimately, its progression leads to patient death. This research work presents the design, synthesis, and characterization of novel imidazotriazole-based thiazolidinone derivatives (1-14), displaying promising anti-Alzheimer's activity. Methods: These derivatives were synthesized by using 1H-imidazole-2-thiol as a starting reagent. Structural characterization was accomplished by 13C-NMR and 1H-NMR, while the molecular weight was confirmed by HREI-MS. These compounds were investigated for their anti-Alzheimer's potential under an in vitro analysis. Results: These compounds showed a significant to moderate biological potential against AChE and BChE in comparison to donepezil (IC50 = 8.50 µM and 8.90 µM against AChE and BuChE), used as a reference drug. Among these compounds, analog 10 with IC50 values of 6.70 µM and 7.10 µM against AChE and BuChE emerged as the lead compound of the series with promising biological efficacy against targeted enzymes. Molecular docking revealed the interactive nature of active ligands against target enzymes. These compounds were also assessed under dynamic conditions to examine the structural deviation and conformational changes in a protein complex structure. DFT calculations provided the relative stability and reactivity of the lead compounds. An ADMET analysis showed that these compounds have no toxicological profile. Conclusions: This research study paves the way for the further development and optimization of novel and selective imidazotriazole-based thiazolidinone inhibitors as potent anti-Alzheimer's agents.

Comparing machine learning classifier models in discriminating cognitively unimpaired older adults from three clinical cohorts in the Alzheimer's disease spectrum: demonstration analyses in the COMPASS-ND study

Background

Research in aging, impairment, and Alzheimer's disease (AD) often requires powerful computational models for discriminating between clinical cohorts and identifying early biomarkers and key risk or protective factors. Machine Learning (ML) approaches represent a diverse set of data-driven tools for performing such tasks in big or complex datasets. We present systematic demonstration analyses to compare seven frequently used ML classifier models and two eXplainable Artificial Intelligence (XAI) techniques on multiple performance metrics for a common neurodegenerative disease dataset. The aim is to identify and characterize the best performing ML and XAI algorithms for the present data.

Method

We accessed a Canadian Consortium on Neurodegeneration in Aging dataset featuring four well-characterized cohorts: Cognitively Unimpaired (CU), Subjective Cognitive Impairment (SCI), Mild Cognitive Impairment (MCI), and AD (N = 255). All participants contributed 102 multi-modal biomarkers and risk factors. Seven ML algorithms were compared along six performance metrics in discriminating between cohorts. Two XAI algorithms were compared using five performance and five similarity metrics.

Results

Although all ML models performed relatively well in the extreme-cohort comparison (CU/AD), the Super Learner (SL), Random Forest (RF) and Gradient-Boosted trees (GB) algorithms excelled in the challenging near-cohort comparisons (CU/SCI). For the XAI interpretation comparison, SHapley Additive exPlanations (SHAP) generally outperformed Local Interpretable Model agnostic Explanation (LIME) in key performance properties.

Conclusion

The ML results indicate that two tree-based methods (RF and GB) are reliable and effective as initial models for classification tasks involving discrete clinical aging and neurodegeneration data. In the XAI phase, SHAP performed better than LIME due to lower computational time (when applied to RF and GB) and incorporation of feature interactions, leading to more reliable results.

Conformationally adaptive therapeutic peptides for diseases caused by intrinsically disordered proteins (IDPs). New paradigm for drug discovery: Target the target, not the arrow

The traditional model of protein structure determined by the amino acid sequence is today seriously challenged by the fact that approximately half of the human proteome is made up of proteins that do not have a stable 3D structure, either partially or in totality. These proteins, called intrinsically disordered proteins (IDPs), are involved in numerous physiological functions and are associated with severe pathologies, e.g. Alzheimer, Parkinson, Creutzfeldt-Jakob, amyotrophic lateral sclerosis (ALS), and type 2 diabetes. Targeting these proteins is challenging for two reasons: i) we need to preserve their physiological functions, and ii) drug design by molecular docking is not possible due to the lack of reliable starting conditions. Faced with this challenge, the solutions proposed by artificial intelligence (AI) such as AlphaFold are clearly unsuitable. Instead, we suggest an innovative approach consisting of mimicking, in short synthetic peptides, the conformational flexibility of IDPs. These peptides, which we call adaptive peptides, are derived from the domains of IDPs that become structured after interacting with a ligand. Adaptive peptides are designed with the aim of selectively antagonizing the harmful effects of IDPs, without targeting them directly but through selected ligands, without affecting their physiological properties. This "target the target, not the arrow" strategy is promised to open a new route to drug discovery for currently undruggable proteins.

Response of Alzheimer's disease-like triple transgenic 3x-Tg mice to experimental migraine evoked by nitroglycerin

Migraine is a disabling chronic condition of the central nervous system (CNS) with accelerated prevalence in females. Emerging studies demonstrated that females with a history of migraine have a 37 % higher risk of developing Alzheimer's disease (AD) compared to same-age males with a history of migraine. To date, it remains unclear how to address sex-associated migraine disorder in patients with AD due to our limited knowledge of the molecular crosstalk behind these two CNS disorders. There are no available animal models that recapitulate both migraine pain and AD phenotypes. Since nitroglycerin (NTG) is widely used in clinics and in experimental wild-type rodent models to monitor migraine symptoms, we aimed to evaluate whether NTG accelerates migraine pain and affects AD hallmarks. Our group and previous reports have shown that the AD-like triple transgenic (3x-Tg) mice demonstrate behavioral changes and pathogenic amyloidogenesis in response to chronic inflammation. Therefore, we treated 3x-Tg mice every other day with ten intraperitoneal injections of NTG or saline. In response to NTG, female 3xTg mice demonstrated accelerated pain responses and diminished cognitive performance during a spatial learning and memory task compared to males and saline exposed groups. We also observed accelerated AD-associated amyloidogenesis in NTG-exposed females compared to the saline group. No sex differences between NTG-treated groups were detected relative to pain threshold, behavioral, and amyloidogenesis changes. Collectively, this novel migraine model induced in AD 3x-Tg mice allowed us to monitor the effect of NTG on the pain threshold, behavioral changes, and pathogenic amyloidogenesis in males and females.

Mild Behavioral Impairment and cognitive functions: A systematic review and meta-analysis

Mild behavioral impairment (MBI) represents a recently introduced diagnostic concept that focuses on behavioral and personality changes occurring in late life and associated with cognitive decline. Nevertheless, the relationship between these dimensions remains unclear. This systematic review and meta-analysis aim to analyze the relationship between MBI and cognitive functioning. The review process was conducted according to the PRISMA-Statement. Restrictions were made, selecting the studies published in peer-review journals, including at least one cognitive measure and presenting the measurement of MBI. Studies that included participants with neurological disorders, dementia, or psychiatric disorders or that only did a neuroimaging or genetic study were excluded. Twenty-two studies were included in the systematic review, while in the meta-analysis seventeen studies featured data to be included in the analyses. The results were classified according to the following cognitive domains: global cognitive functioning, memory, language, attention executive functions, visuospatial skills, and processing speed. In the quantitative analysis, only global cognitive functioning, executive function, attention, and memory were evaluated. The results of both qualitative and quantitative analysis indicate that individuals with MBI exhibited diminished performance on cognitive tasks when compared to those without MBI symptoms. These results are stronger when evaluating the various domains individually (particularly memory and executive functions) than when a global assessment was made. These findings highlight the potential role of MBI symptoms as early indicators of neurodegenerative processes, reinforcing the necessity for comprehensive assessments that encompass both behavioral and cognitive evaluations. The early detection of these symptoms in prodromal phases can be very useful for the development of non-pharmacological interventions and may provide relevant guidelines for clinicians in the management and diagnosis of neurodegenerative disorders.

Physical activity and neuroplasticity in neurodegenerative disorders: a comprehensive review of exercise interventions, cognitive training, and AI applications

This review aimed to elucidate the mechanisms through which (i) physical activity (PA) enhances neuroplasticity and cognitive function in neurodegenerative disorders, and (ii) identify specific PA interventions for improving cognitive rehabilitation programs. We conducted a literature search in PubMed, Medline, Scopus, Web of Science, and PsycINFO, covering publications from January 1990 to August 2024. The search strategy employed key terms related to neuroplasticity, physical exercise, cognitive function, neurodegenerative disorders, and personalized physical activity. Inclusion criteria included original research on the relationship between PA and neuroplasticity in neurodegenerative disorders, while exclusion criteria eliminated studies focusing solely on pharmacological interventions. The review identified multiple pathways through which PA may enhance neuroplasticity, including releasing neurotrophic factors, modulation of neuroinflammation, reduction of oxidative stress, and enhancement of synaptic connectivity and neurogenesis. Aerobic exercise was found to increase hippocampal volume by 1-2% and improve executive function scores by 5-10% in older adults. Resistance training enhanced cognitive control and memory performance by 12-18% in elderly individuals. Mind-body exercises, such as yoga and tai-chi, improved gray matter density in memory-related brain regions by 3-5% and enhanced emotional regulation scores by 15-20%. Dual-task training improved attention and processing speed by 8-14% in individuals with neurodegenerative disorders. We also discuss the potential role of AI-based exercise and AI cognitive training in preventing and rehabilitating neurodegenerative illnesses, highlighting innovative approaches to personalized interventions and improved patient outcomes. PA significantly enhances neuroplasticity and cognitive function in neurodegenerative disorders through various mechanisms. Aerobic exercise, resistance training, mind-body practices, and dual-task exercises each offer unique cognitive benefits. Implementing these activities in clinical settings can improve patient outcomes. Future research should focus on creating personalized interventions tailored to specific conditions, incorporating personalized physical exercise programs to optimize cognitive rehabilitation.

A review of AI-based radiogenomics in neurodegenerative disease

Neurodegenerative diseases are chronic, progressive conditions that cause irreversible damage to the nervous system, particularly in aging populations. Early diagnosis is a critical challenge, as these diseases often develop slowly and without clear symptoms until significant damage has occurred. Recent advances in radiomics and genomics have provided valuable insights into the mechanisms of these diseases by identifying specific imaging features and genomic patterns. Radiogenomics enhances diagnostic capabilities by linking genomics with imaging phenotypes, offering a more comprehensive understanding of disease progression. The growing field of artificial intelligence (AI), including machine learning and deep learning, opens new opportunities for improving the accuracy and timeliness of these diagnoses. This review examines the application of AI-based radiogenomics in neurodegenerative diseases, summarizing key model designs, performance metrics, publicly available data resources, significant findings, and future research directions. It provides a starting point and guidance for those seeking to explore this emerging area of study.

Emerging Role of Mesenchymal Stromal Cell and Exosome Therapies in Treating Cognitive Impairment

Cognitive aging, characterized by the gradual decline in cognitive functions such as memory, attention, and problem-solving, significantly impacts daily life. This decline is often accelerated by neurodegenerative diseases, particularly Alzheimer's Disease (AD) and Parkinson's Disease (PD). AD is marked by the accumulation of amyloid-beta plaques and tau tangles, whereas PD involves the degeneration of dopaminergic neurons. Both conditions lead to severe cognitive impairment, greatly diminishing the quality of life for affected individuals. Recent advancements in regenerative medicine have highlighted mesenchymal stromal cells (MSCs) and their derived exosomes as promising therapeutic options. MSCs possess regenerative, neuroprotective, and immunomodulatory properties, which can promote neurogenesis, reduce inflammation, and support neuronal health. Exosomes, nanosized vesicles derived from MSCs, provide an efficient means for delivering bioactive molecules across the blood-brain barrier, targeting the underlying pathologies of AD and PD. While these therapies hold great promise, challenges such as variability in MSC sources, optimal dosing, and effective delivery methods need to be addressed for clinical application. The development of robust protocols, along with rigorous clinical trials, is crucial for validating the safety and efficacy of MSC and exosome therapies. Future research should focus on overcoming these barriers, optimizing treatment strategies, and exploring the integration of MSC and exosome therapies with lifestyle interventions. By addressing these challenges, MSC- and exosome-based therapies could offer transformative solutions for improving outcomes and enhancing the quality of life for individuals affected by cognitive aging and neurodegenerative diseases.

The role of Apolipoprotein E4 on cognitive impairment in Parkinson's disease and Parkinsonisms

Cognitive impairment is a prevalent non-motor symptom of Parkinson's disease (PD), increasing the risk of dementia as the disease progresses. Despite its clinical significance, the etiology of cognitive impairment in PD remains unclear. Apolipoprotein E4 (APOE4), a well-known genetic risk factor of Alzheimer's disease, has been studied for its potential role in PD-related cognitive impairment. However, findings have been conflicting and thus inconclusive, highlighting a need to critically evaluate the current research. Several studies using neuroimaging modalities have explored the brains of individuals with PD and atypical parkinsonian disorders who have APOE4. Some of these studies have identified distinct neuropathological changes that have been previously reported to be associated with cognitive impairments in those with Parkinsonisms. Here, we review the role of APOE4 on cognitive impairment in PD and atypical Parkinsonisms using neuroimaging evidence. We will examine how APOE4 may contribute to pathological changes within the brain and its association with cognitive impairment.

Remembering what did not happen: the role of hypnosis in memory recall and false memories formation

Memory recall is subject to errors that can lead to the formation of false memories. Several factors affect memory processes, such as attention deficits or emotional distress. Additionally, cardiovascular diseases may lead to cognitive decline and memory loss, also increasing the occurrence of false events recall. Hypnosis has proved to affect the autonomic nervous system, positively impacting the cardiovascular response. Hypnosis has also been suggested as a tool to enhance memory and autobiographical events recall in both healthy and unhealthy individuals; however, this approach has led to several controversies. Particularly, the employment of hypnosis in autobiographical recall (hypnotic regression) has been accused of favoring the creation of false memories, leading to therapeutic fallacy. In this paper, we review the current literature on the mechanisms behind the creation of false memories and the role played by hypnosis in memory enhancement and false memory recall. The evidence here collected suggests that cardiovascular diseases affect brain health contributing to cognitive decline and memory impairments, also increasing the occurrence of false memories. Hypnosis induces an increase in parasympathetic activity and a decrease in sympathetic activity, suggesting a potential role in preventing some cardiovascular diseases, such as hypertension, which in turn may improve brain health. Additionally, hypnosis has been shown to have some effectiveness in enhancing memory functions, although contradictory findings reported by several studies make it difficult to draw proper conclusions. Hypnotic regression and guided imagery should be used with caution as they may unintentionally lead to false memory recall. Nevertheless, further studies are required to better understand the effects of hypnosis on the brain and the heart and how it can be used to enhance memory, especially in people with cognitive decline.

Bauhinia coccinea extract prevents memory loss induced by scopolamine through activation of antiapoptotic and antioxidant pathways in mice

Alzheimer's disease (AD) is characterized by oxidative stress-mediated memory dysfunction and neuronal cell death. This study investigated the effects of an ethanol extract from Bauhinia coccinea (EEBC) on memory impairment and neuronal damage in a memory deficit mouse model. EEBC was administered to ICR mice at doses of 50, 100, or 200 mg/kg daily for 3 weeks. Cognitive impairment was induced via scopolamine (SCO) injection. Brain tissues were analyzed for acetylcholine (ACh) levels, acetylcholinesterase (AChE) activity, neuronal apoptosis, and antioxidant markers. Behavioral tests showed that SCO injection induced memory loss, whereas EEBC significantly ameliorated SCO-mediated memory impairment. EEBC regulated the cholinergic system by decreasing ACh levels and enhancing AChE activity. Nissl staining and immunohistochemistry for NeuN showed that EEBC exerted neuroprotective effects in SCO-injected mice brains. Moreover, EEBC significantly reduced the number of terminal deoxynucleotidyl transferase dUTP nick end labeling-positive apoptotic cells increased by SCO treatment. EEBC also reversed the SCO-induced changes in apoptosis-related protein expression in brain tissues. Furthermore, EEBC significantly reduced malondialdehyde levels and activated catalase in SCO-administered brains. Quantitative RNA sequencing showed involvement of lipid metabolism in EEBC memory function regulation. Thus, EEBC is a promising candidate for attenuating AD progression as it targets the cholinergic system and neuronal apoptosis.

Teratological, neurochemical and histomorphic changes in the limbic areas of F1 mice progeny due to co-parental polystyrene nanoplastic exposure

In the present study, co-parental exposure to polystyrene nanoplastics (PS-NPs) elicits profound teratological impacts, including skeletal and visceral malformations, post-natal effects on neonatal growth and neurobehavioral development in F1 progeny. A comprehensive investigation was conducted on Swiss albino mice fetuses, neonates (PND 1-21) and adult mice offsprings (PND 60) following parental exposure during spermatogenesis and oogenesis period, as well as continued maternal exposure during gestation and weaning. The parental mice were administered PS-NPs via oral gavage at low dose (0.2 mg/kg/day) and high dose (1 mg/kg/day). Both male and female parental mice were exposed to PS-NPs for 60 days and 14 days, respectively before mating. After the mating, the pregnant female mice continued to receive PS-NPs treatment during the gestation, till the subsequent weaning period. Our findings revealed that PS-NPs led to significant reductions in growth, and heightened skeletal and visceral anomalies in developing fetuses. Exposure further impaired reflexes in neonatal mice such as grasping, surface righting and negative geotaxis. Moreover, the adult progeny also exhibited learning impairments. Neurodevelopmental assessment unveiled alterations in neurotransmitter levels, antioxidant enzyme activities, and structural changes in key limbic areas such as the cortex, hippocampus, and hypothalamus of adult mice offspring. These alterations included increased vacuolization, vascular dilation, and reduced pyramidal neurons in the hippocampus. Thus, this transgenerational study underscores the detrimental effects of PS-NPs on both prenatal and postnatal development, emphasizing teratological and enduring neurological consequences in the limbic regions of F1 progeny mice brains.

Heterogeneous treatment effects of BCG vaccine on Alzheimer's disease risk

Background

This project has investigated the role of the Bacillus Calmette-Guérin (BCG) vaccine as a potential treatment against Alzheimer's disease (AD) and related dementias (ADRD).

Objective

To further establish that BCG treatment results in lower risk of ADRD through novel machine learning methods and to analyze the heterogeneity of treatment effects.

Methods

This retrospective cohort study was conducted from May 28, 1987 to May 6, 2021, in patients who were 50 years or older and were diagnosed with non-muscle-invasive bladder cancer (NMIBC). Follow-up duration was 15-years. Machine learning algorithms using survival analysis and the random forest algorithm were the primary methods of data analysis.

Results

The research has found that on average, NMIBC patients who received BCG treatment had a 6.9% (95% CI: 0.43%, 13.4%) lower risk of developing ADRD compared to those who did not. Heterogeneous treatment effects were also detected for those with a history of mental health disorders and also for those with a history of respiratory diseases. Those with mental health disorders were at a 14.7% (95% CI: 0.6%, 28.9%) reduced risk of ADRD if they received BCG treatment compared to no BCG treatment. Additionally, those taking BCG with respiratory diseases increased risk of ADRD by 13.6% (95% CI: 1.1%, 26.1%) compared to those with no BCG treatment.

Conclusions

BCG is associated with a lower risk of ADRD through novel analysis methods and has detected heterogeneity of treatment effects. This presents BCG as a potential low-cost method, with few side-effects, to prevent ADRD.

Research on Alzheimer's Disease (AD) Involving the Use of In vivo and In vitro Models and Mechanisms

BACKGROUND

Alzheimer's Disease (AD) is a neurodegenerative disorder characterized by the progressive formation of extracellular amyloid plaques, intracellular neurofibrillary tangles, inflammation, and impaired antioxidant systems. Early detection and intervention are vital for managing AD effectively.

OBJECTIVES

This review scrutinizes both in-vivo and in-vitro screening models employed in Alzheimer's disease research. in-vivo models, including transgenic mice expressing AD-related mutations, offer profound insights into disease progression and potential therapeutic targets. A thorough understanding of these models and mechanisms will facilitate the development of novel therapies and interventions for Alzheimer's disease. This review aims to provide an overview of the current experimental models in AD research, assess their strengths and weaknesses as model systems, and underscore the future prospects of experimental AD modeling.

METHODS

We conducted a systematic literature search across multiple databases, such as Pub- Med, Bentham Science, Elsevier, Springer Nature, Wiley, and Research Gate. The search strategy incorporated pertinent keywords related to Alzheimer's disease, in-vivo models, in-vitro models, and screening mechanisms. Inclusion criteria were established to identify studies focused on in-vivo and in-vitro screening models and their mechanisms in Alzheimer's disease research. Studies not meeting the predefined criteria were excluded from the review.

RESULTS

A well-structured experimental animal model can yield significant insights into the neurobiology of AD, enhancing our comprehension of its pathogenesis and the potential for cutting-edge therapeutic strategies. Given the limited efficacy of current AD medications, there is a pressing need for the development of experimental models that can mimic the disease, particularly in pre-symptomatic stages, to investigate prevention and treatment approaches. To address this requirement, numerous experimental models replicating human AD pathology have been established, serving as invaluable tools for assessing potential treatments.

CONCLUSION

In summary, this comprehensive review underscores the pivotal role of in-vivo and in-vitro screening models in advancing our understanding of Alzheimer's disease. These models offer invaluable insights into disease progression, pathological mechanisms, and potential therapeutic targets. By conducting a rigorous investigation and evaluation of these models and mechanisms, effective screening and treatment methods for Alzheimer's disease can be devised. The review also outlines future research directions and areas for enhancing AD screening models.

Chronic exposure to a synthetic cannabinoid improves cognition and increases locomotor activity in Tg4-42 Alzheimer's disease mice

Background

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by cognitive decline and behavior impairments. Despite recent approvals of anti-amyloid antibodies, there remains a need for disease modifying and easily accessible therapies. Emerging evidence suggests that targeting the endocannabinoid system may hold promise for AD therapy as it plays a crucial role in different physiological processes, including learning, memory and anxiety, as well as inflammatory and immune responses.

Objective

In this study, we investigated the therapeutic potential of the synthetic cannabinoid WIN 55,212-2 on memory deficits in Tg4-42 transgenic mice.

Methods

Tg4-42 mice were assigned to two treatment groups to investigate the preventive effects of WIN 55,212-2 after a prolonged washout period, as well as the therapeutic effects of WIN 55,212-2 on behavior. Furthermore, the effects of WIN 55,212-2 treatment on AD pathology, including inflammation, amyloid-β load, neurogenesis, and brain glucose metabolism, were evaluated.

Results

Therapeutic WIN 55,212-2 treatment rescued recognition memory and spatial reference deficits in Tg4-42 mice. Furthermore, therapeutic WIN 55,212-2 administration improved motor performance. In addition, preventative WIN 55,212-2 treatment rescued spatial learning and reference memory deficits. Importantly, WIN 55,212-2 treatment did not affect anxiety-like behavior. However, therapeutic and preventative WIN 55,212-2 treatment resulted in an increase locomotor activity and swimming speed in Tg4-42 mice. WIN-treatment reduced microgliosis in the hippocampus of preventively treated mice and rescued brain glucose metabolism in therapeutically treated Tg4-42 mice.

Conclusions

Our findings emphasize the therapeutic promise of the synthetic cannabinoid WIN 55,212-2 in alleviating behavioral and cognitive deficits linked to AD.

Effects of idebenone on cognitive function and serum biomarkers in patients with amnestic mild cognitive impairment

OBJECTIVES

This retrospective study aimed to investigate the effects of idebenone on cognitive function and serum levels of superoxide dismutase (SOD) and high-sensitivity C-reactive protein (hs-CRP) in individuals with amnestic mild cognitive impairment (aMCI).

METHODS

Retrospective data were collected from the Neurology outpatient department of Liaocheng People's Hospital from January 2021 to June 2023. Patients with a newly diagnosed aMCI who received treatment were included in the idebenone treatment group. The treatment group took 30 mg of oral idebenone three times a day for 6 months. A control group of 51 MCI patients who did not receive cholinesterase inhibitors or other cognitive-enhancing drugs during the period was selected. Cognitive function assessments and serum Biomarkers were conducted before and after treatment in both groups.

RESULTS

MoCA scores were significantly improved after 6 months of idebenone treatment, and the difference was statistically significant. The delayed recall score was significantly improved, and the difference was statistically significant; The level of SOD increased and the level of high-sensitivity C-reactive protein decreased after the treatment, but there was no significant change in the control group.

CONCLUSIONS

The results of this study demonstrate that idebenone treatment significantly improves cognitive function in individuals with aMCI, particularly in the domain of delayed memory. In addition, idebenone reduces the degree of inflammation and oxidative stress and improves antioxidant levels. These findings suggest that idebenone may be a promising intervention for the management of cognitive impairments associated with aMCI.

Exploring the gut-brain axis in alzheimer's disease treatment via probiotics: evidence from animal studies-a systematic review and meta-analysis

INTRODUCTION

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder in the elderly, causing cognitive impairment. Its pathogenesis is characterized by amyloid beta deposition, neurofibrillary tangles, and neuroinflammation. Recent research has identified the link between gut dysbiosis, an imbalance of intestinal microorganisms, to this pathogenesis via the gut-brain axis. This study aims to review the probiotics' therapeutic effect, targeting the gut-brain axis, for AD treatment in animals.

METHODS

The method utilized in this study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Three reviewers searched articles through PubMed, Scopus, and Embase using advanced search strategy. Articles published between 2010 and 2023 that met the criteria were included.

RESULTS

Of 2,273 articles, 21 animal studies measuring the effects of probiotics genera Lactobacillus and/or Bifidobacterium on AD via at least one of these four outcomes: AD pathology, cognitive function, neuroinflammation, and gut microbiota composition. The results demonstrated that probiotics could repair gut dysbiosis by decreasing pro-inflammatory bacteria and increasing anti-inflammatory bacteria. Repaired dysbiosis was found to be associated with less neuroinflammation as significant reductions in neuroinflammatory markers related to the pathogenesis of AD such as TNF-α (SMD = -2.08, P = 0.005), IL-6 (SMD = -2.98, P < 0.0005), and IL-1β (SMD = -2.49, P = 0.003) were observed. Reduced amyloid beta deposition (SMD = -1.17, P = 0.009) was reported, but reduction in tau hyperphosphorylation was found to be insignificant. For cognitive function, positive results were demonstrated for all three aspects of cognitive function including long-term memory (SMD = 2.55, P < 0.00001), short-term memory (SMD = 1.32, P = 0.003), and spatial recognition (SMD = -1.13, P < 0.00001).

CONCLUSIONS

Particular formulas of probiotics showed potential effectiveness in AD therapies with demonstrated association with the gut-brain axis. Future studies are required to investigate strain-specific results and optimal dosages and regimens.

Alzheimer's disease: a comprehensive review of epidemiology, risk factors, symptoms diagnosis, management, caregiving, advanced treatments and associated challenges

Background

Alzheimer's disease (AD) is a chronic, progressive neurodegenerative disorder characterized by cognitive decline, memory loss, and impaired reasoning. It is the leading cause of dementia in older adults, marked by the pathological accumulation of amyloid-beta plaques and neurofibrillary tangles. These pathological changes lead to widespread neuronal damage, significantly impacting daily functioning and quality of life.

Objective

This comprehensive review aims to explore various aspects of Alzheimer's disease, including its epidemiology, risk factors, clinical presentation, diagnostic advancements, management strategies, caregiving challenges, and emerging therapeutic interventions.

Methods

A systematic literature review was conducted across multiple electronic databases, including PubMed, MEDLINE, Cochrane Library, and Scopus, from their inception to May 2024. The search strategy incorporated a combination of keywords and Medical Subject Headings (MeSH) terms such as "Alzheimer's disease," "epidemiology," "risk factors," "symptoms," "diagnosis," "management," "caregiving," "treatment," and "novel therapies." Boolean operators (AND, OR) were used to refine the search, ensuring a comprehensive analysis of the existing literature on Alzheimer's disease.

Results

AD is significantly influenced by genetic predispositions, such as the apolipoprotein E (APOE) ε4 allele, along with modifiable environmental factors like diet, physical activity, and cognitive engagement. Diagnostic approaches have evolved with advances in neuroimaging techniques (MRI, PET), and biomarker analysis, allowing for earlier detection and intervention. The National Institute on Aging and the Alzheimer's Association have updated diagnostic criteria to include biomarker data, enhancing early diagnosis.

Conclusion

The management of AD includes pharmacological treatments, such as cholinesterase inhibitors and NMDA receptor antagonists, which provide symptomatic relief but do not slow disease progression. Emerging therapies, including amyloid-beta and tau-targeting treatments, gene therapy, and immunotherapy, offer potential for disease modification. The critical role of caregivers is underscored, as they face considerable emotional, physical, and financial burdens. Support programs, communication strategies, and educational interventions are essential for improving caregiving outcomes. While significant advancements have been made in understanding and managing AD, ongoing research is necessary to identify new therapeutic targets and enhance diagnostic and treatment strategies. A holistic approach, integrating clinical, genetic, and environmental factors, is essential for addressing the multifaceted challenges of Alzheimer's disease and improving outcomes for both patients and caregivers.

Mild cognitive impairment in pemphigus

BACKGROUND

Pemphigus is a group of autoimmune blistering disorders that have been associated with dementia in previous studies. Mild cognitive impairment (MCI) can be the first stage of progression into dementia. The objective of the present study was to evaluate the frequency of MCI in pemphigus patients compared to a control group.

METHODS

This case-control study included 80 patients with pemphigus referred to the dermatology clinics of Shohadaye Tajrish and Loghman Hakim hospitals, Tehran, Iran, in 2021. A group of 80 individuals without pemphigus who visited the same clinics for cosmetic consultation or interventions were regarded as controls. Age, sex, marital status, and education were recorded for all participants. Disease duration, medications, and severity were noted for pemphigus patients. The Persian version of the Montreal Cognitive Assessment (MoCA) test was used to assess cognitive function.

RESULTS

MCI was significantly more frequent in pemphigus patients than in controls (55% vs. 37.5%, P = 0.026). Furthermore, the total MoCA score was significantly lower in pemphigus patients compared to controls (23.98 ± 3.77 vs. 25.21 ± 3.45, P = 0.032); however, among MoCA's different domains, only the executive functions score was significantly lower in pemphigus patients (P = 0.010). After adjustment, multivariable logistic regression analysis revealed that every 1-year higher education in patients decreased the odds of MCI by 52% (adjusted odds ratio = 0.483, 95% confidence interval 0.326; 0.715, P < 0.001).

CONCLUSIONS

The frequency of MCI was found to be significantly higher, and overall scores of the MoCA test, as well as its executive function domain, were significantly lower among pemphigus patients in this study compared to the control group. Additionally, a higher level of education was associated with decreased odds of MCI in pemphigus patients. Identifying pemphigus patients with MCI through the use of the MoCA test can facilitate early intervention, enabling them to seek help and support.

Individualized, cross-validated prediction of future dementia using cognitive assessments in people with mild cognitive symptoms

INTRODUCTION

We aimed to develop an algorithm to predict the individualized risk of future dementia using brief cognitive tests suitable for primary care.

METHODS

We included 612 participants with subjective cognitive decline (SCD) or mild cognitive impairment (MCI) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) study, assessed for at least 4 years or until progression to dementia. A logistic regression model, using cognitive tests as predictors and dementia progression as an outcome, stratified participants into low, intermediate, or high risk. A second model, including 1-year cognitive test changes, was applied to the intermediate group. The models were replicated in 392 SCD/MCI participants from the BioFINDER-1 study.

RESULTS

The best two-step model for predicting dementia incorporated Trail Making Test B (attention/executive function), Animal Fluency (verbal fluency), Mini-Mental State Examination (global cognition), and 10-word list recall (memory). The model's positive predictive value in ADNI was 85.8% and negative predictive value was 92.2% versus 62.5% and 95.6%, respectively, in BioFINDER-1.

DISCUSSION

This two-step model accurately predicts individualized dementia risk.

HIGHLIGHTS

To our knowledge, this is the first algorithm for predicting all-cause dementia using a novel two-step model utilizing brief cognitive tests. Applying a validated model including the Trail Making Test B, Animal Fluency, MMSE, Alzheimer's Disease Assessment Scale delayed, and immediate recall can robustly and accurately categorize individuals into low, intermediate, or high risk of dementia progression and can facilitate clinical decision-making and personalized patient care. We created an app that is available for research and educational purposes at https://brainapps.shinyapps.io/PredictAllCauseDementia to provide an individualized risk score for dementia progression.

Chemical Characterization and Assessment of the Neuroprotective Potential of Euphrasia officinalis

Euphrasia officinalis L., commonly known as eyebright, is a medicinal plant used in folk medicine for eye disorders and memory loss. Due to its abundance of compounds with proven neuroprotective properties, there has been growing interest in exploring eyebright's potential health benefits, particularly for preventing or treating neurodegenerative diseases like Alzheimer's disease. Here, seven distinct extracts were generated using solvents of different polarities, consecutively, from plants grown in Greece. The extracts were chemically characterized and assessed for their antioxidant, anticholinesterase, and anti-neurotoxic potentials. Our findings demonstrated eyebright's notable antioxidant capacity with five extracts exhibiting significant anti-neurotoxic properties by enhancing cell viability by 17.5 to 22.6% in human neuroblastoma cells exposed to neurotoxic amyloid-beta peptides. The ethyl acetate and butanolic extracts were the most effective across all assays, likely due to their high concentrations of active compounds. Therefore, eyebright may be harnessed for developing functional foods, supplements, and pharmaceuticals with potential benefits against Alzheimer's disease. This study marks the first identification of neuroprotective properties in a Euphrasia species, highlighting its broader therapeutic potential and paving the way for further research.

Pilot: Salivary Lactoferrin as a Biomarker of Alzheimer's Disease

Background

Alzheimer's disease (AD) research has focused on developing accessible biomarkers that accurately detect disease pathology and progression before symptoms present. Lactoferrin (Lf) is an iron-binding antimicrobial glycoprotein found in all biological fluids, and its concentration in saliva has been correlated with AD symptoms. This pilot project aimed to determine whether salivary lactoferrin (sLF) has potential as a biomarker for AD.

Methods

Participants were middle to older-aged non-Hispanic white (NHW) and Black Americans (BA) at risk for AD due to parental history. We collected saliva samples after an 8-hour fast and administered a cognitive battery assessing executive function, memory, visuospatial ability, attention, and verbal fluency. We examined the relationship between sLF and cognitive performance and evaluated protein concentration across races.

Results

Seventeen middle-to-older-aged (age = 60.29 ± 9.7 years) BA and NHWs were enrolled. After controlling for age, sex, race, and years of education, we found a significant r between sLF and Digit Span Memory Test (DSMT) scores (P = 0.013) and a modest correlation with Mental Rotation Test scores (P = 0.194). We found no difference in average concentration across races.

Conclusions

Memory concerns and a worsening in visuospatial ability are early signs of cognitive decline in AD patients, and this pilot suggests a correlation of these symptoms with sLF. Bigger-scale longitudinal studies to examine the relationship between sLF and established AD biomarkers in diverse populations are needed to assess its clinical usefulness as an early biomarker for AD.

Eplingiella fruticosa leaf essential oil complexed with β-cyclodextrin exerts a neuroprotective effect in an Alzheimer's disease animal model induced by Streptozotocin

Alzheimer's Disease (AD) is physiopathologically marked by an accumulation of beta-amyloid peptide (Aβ), hyperphosphorylation of tau protein, inflammation, and oxidative stress in the brain tissue. While new drugs for AD have been approved, novel treatments are still needed. Eplingiella fruticosa (EF) has demonstrated anti-inflammatory and antioxidant properties, which may be beneficial against AD. This study aimed to evaluate the effects of EF leaf essential oil complexed with β-cyclodextrin in a sporadic AD model induced by streptozotocin (STZ). Male Wistar rats (5-6 months old) received an intracerebroventricular STZ injection (3 mg/kg) or vehicle, and were orally treated with vehicle, EF (5 mg/kg), or donepezil (5 mg/kg) for 14 days. Behavioral tests included olfactory discrimination, open field, novel object recognition, sucrose preference, and spontaneous alternation. Upon completion, rats were euthanatized, and their brains were analyzed for Aβ, tau, and IL-1β via immunohistochemistry, and for oxidative stress markers. STZ-treated rats showed memory deficits and anhedonia, accompanied by increased Aβ, tau, and IL-1β immunoreactivity in the olfactory bulb, cortex, hippocampus, and increased TBARS levels in the hippocampus. On the other hand, EF treatment improved short-term and working memory (p < 0.001), and reduced depressive-like behavior (p = 0.02). Additionally, EF treatment decreased Aβ, tau, and IL-1β immunoreactivity in the olfactory bulb, hippocampus and cortex (p < 0.05), and reduced TBARS levels (p = 0.04) and total oxidant status in the hippocampus (p = 0.03), and increased total antioxidant status in the cortex (p = 0.04). These findings suggest EF has neuroprotective effects against STZ-induced damage, indicating its potential as a novel compound for AD treatment.

Implications of liquid-liquid phase separation and ferroptosis in Alzheimer's disease

Neuronal cell demise represents a prevalent occurrence throughout the advancement of Alzheimer's disease (AD). However, the mechanism of triggering the death of neuronal cells remains unclear. Its potential mechanisms include aggregation of soluble amyloid-beta (Aβ) to form insoluble amyloid plaques, abnormal phosphorylation of tau protein and formation of intracellular neurofibrillary tangles (NFTs), neuroinflammation, ferroptosis, oxidative stress, liquid-liquid phase separation (LLPS) and metal ion disorders. Among them, ferroptosis is an iron-dependent lipid peroxidation-driven cell death and emerging evidences have demonstrated the involvement of ferroptosis in the pathological process of AD. The sensitivity to ferroptosis is tightly linked to numerous biological processes. Moreover, emerging evidences indicate that LLPS has great impacts on regulating human health and diseases, especially AD. Soluble Aβ can undergo LLPS to form liquid-like droplets, which can lead to the formation of insoluble amyloid plaques. Meanwhile, tau has a high propensity to condensate via the mechanism of LLPS, which can lead to the formation of NFTs. In this review, we summarize the most recent advancements pertaining to LLPS and ferroptosis in AD. Our primary focus is on expounding the influence of Aβ, tau protein, iron ions, and lipid oxidation on the intricate mechanisms underlying ferroptosis and LLPS within the domain of AD pathology. Additionally, we delve into the intricate cross-interactions that occur between LLPS and ferroptosis in the context of AD. Our findings are expected to serve as a theoretical and experimental foundation for clinical research and targeted therapy for AD.

Synergistic association of Aβ and tau pathology with cortical neurophysiology and cognitive decline in asymptomatic older adults

Animal and computational models of Alzheimer's disease (AD) indicate that early amyloid-β (Aβ) deposits drive neurons into a hyperactive regime, and that subsequent tau depositions manifest an opposite, suppressive effect as behavioral deficits emerge. Here we report analogous changes in macroscopic oscillatory neurophysiology in the human brain. We used positron emission tomography and task-free magnetoencephalography to test the effects of Aβ and tau deposition on cortical neurophysiology in 104 cognitively unimpaired older adults with a family history of sporadic AD. In these asymptomatic individuals, we found that Aβ depositions colocalize with accelerated neurophysiological activity. In those also presenting medial-temporal tau pathology, linear mixed effects of Aβ and tau depositions indicate a shift toward slower neurophysiological activity, which was also linked to cognitive decline. We conclude that early Aβ and tau depositions relate synergistically to human cortical neurophysiology and subsequent cognitive decline. Our findings provide insight into the multifaceted neurophysiological mechanisms engaged in the preclinical phases of AD.

Exploring the therapeutic potential of Potentilla fragarioides var. major (Rosaceae) extract in Alzheimer's disease using in vitro and in vivo models: A multi-faceted approach

Alzheimer's disease (AD) is the most common cause of dementia and is caused by various factors including amyloid-beta (Aβ) aggregation. We investigated the pharmacological effects of the ethanol extract of Potentilla fragarioides var. major (Rosaceae) (EEPF) on AD-related pathogenesis, which remain elusive. We observed the effects of EEPF on Aβ disaggregation and free-radical scavenging activities for 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) using in vitro assays, evaluated the effects of EEPF on memory loss in two animal models, and examined the molecular regulatory mechanisms of EEPF using an antibody-protein microarray in EEPF-treated neuronal cell lines. EEPF inhibited Aβ aggregation in a concentration-dependent manner and enhanced free-radical scavenging activities for ABTS and DPPH. EEPF significantly inhibited memory impairment in the passive avoidance task, Y-maze test, and Morris water maze test in scopolamine-induced short-term memory loss mice and Aβ-injected AD-like mice. Nissl staining and immunohistochemistry for NeuN and Iba-1 confirmed the neuroprotective and anti-inflammatory effects of EEPF in both animal models. In H2O2-treated HT22 hippocampal cells, EEPF significantly prevented cell damage, enhanced CaMK2, and reduced ferric reductase. In lipopolysaccharide (LPS)-stimulated BV-2 microglia, EEPF significantly inhibited LPS-induced production of inflammatory factors, such as nitric oxide, prostaglandin E2, tumor necrosis factor-α, and interleukin-6, and decreased the phosphorylation of Smad3 and cyclin D3. High-performance liquid chromatography confirmed that EEPF has five major components: neochlorogenic acid, chlorogenic acid, polydatin, isochlorogenic acid A, and buddleoside, with amounts ranging across 1.91-9.41 mg/g. EEPF may be a promising drug for treatment of AD and AD-related brain disorders.

Genetic studies through the lens of gene networks

Understanding the genetic basis of complex traits is a longstanding challenge in the field of genomics. Genome-wide association studies (GWAS) have identified thousands of variant-trait associations, but most of these variants are located in non-coding regions, making the link to biological function elusive. While traditional approaches, such as transcriptome-wide association studies (TWAS), have advanced our understanding by linking genetic variants to gene expression, they often overlook gene-gene interactions. Here, we review current approaches to integrate different molecular data, leveraging machine learning methods to identify gene modules based on co-expression and functional relationships. These integrative approaches, like PhenoPLIER, combine TWAS and drug-induced transcriptional profiles to effectively capture biologically meaningful gene networks. This integration provides a context-specific understanding of disease processes while highlighting both core and peripheral genes. These insights pave the way for novel therapeutic targets and enhance the interpretability of genetic studies in personalized medicine.

Beyond anosmia: olfactory dysfunction as a common denominator in neurodegenerative and neurodevelopmental disorders

Olfactory dysfunction has emerged as a hallmark feature shared among several neurological conditions, including both neurodevelopmental and neurodegenerative disorders. While diseases of both categories have been extensively studied for decades, their association with olfaction has only recently gained attention. Olfactory deficits often manifest already during prodromal stages of these diseases, yet it remains unclear whether common pathophysiological changes along olfactory pathways cause such impairments. Here we probe into the intricate relationship between olfactory dysfunction and neurodegenerative and neurodevelopmental disorders, shedding light on their commonalities and underlying mechanisms. We begin by providing a brief overview of the olfactory circuit and its connections to higher-associated brain areas. Additionally, we discuss olfactory deficits in these disorders, focusing on potential common mechanisms that may contribute to olfactory dysfunction across both types of disorders. We further debate whether olfactory deficits contribute to the disease propagation or are simply an epiphenomenon. We conclude by emphasizing the significance of olfactory function as a potential pre-clinical diagnostic tool to identify individuals with neurological disorders that offers the opportunity for preventive intervention before other symptoms manifest.

The effect of probiotics on select cognitive domains in mild cognitive impairment and Alzheimer's disease: A systematic review and meta-analysis

Background

Mild cognitive impairment (MCI) and Alzheimer's disease (AD) are progressive neurodegenerative disorders, and probiotics may offer therapeutic benefits by modulating gut microbiota and reducing inflammation.

Objective

This study systematically evaluated the impact of probiotics on cognitive function in MCI and AD through a meta-analysis of randomized controlled trials (RCTs).

Methods

A systematic review and meta-analysis were performed following PRISMA 2020 guidelines. PubMed, Embase, EBSCO, and Cochrane databases were searched for RCTs (January 2000-January 2024) on probiotic interventions lasting 8-24 weeks. Cognitive outcomes included Mini-Mental State Examination (MMSE), Montreal Cognitive Assessment (MoCA), language, naming, visual-spatial, memory, and attention. Data were analyzed using R with a random-effects model to calculate pooled standardized mean differences (SMDs) with 95% confidence intervals (CIs). Risk of bias was rigorously assessed.

Results

Out of 2000 articles, 500 full texts were screened, and 10 studies were included. The meta-analysis showed varied effect sizes: MMSE (SMD: 0.28, 95%CI -0.35-0.91, p = 0.38), MoCA (SMD: 0.51, 95%CI -0.49-1.52, p = 0.33), language (SMD: -0.12, 95% CI -0.54-0.29, p = 0.56), naming (SMD: 0.02, 95%CI -0.69-0.74, p = 0.95), visual-spatial (SMD: 0.38, 95%CI -0.13-0.88, p = 0.14), memory (SMD: 0.20, 95%CI -0.15-0.55, p = 0.26), and attention (SMD: -0.07, 95%CI -0.44-0.30, p = 0.71). Positive SMDs suggest cognitive improvement, while non-significant negative SMDs indicate trends toward decline, inclined by probiotic strains, duration, and participant characteristics.

Conclusions

Probiotics did not significantly improve cognitive function in MCI and AD patients, with variability in effects across cognitive domains, suggesting the need for tailored interventions and future studies.

Correlation between iron deposition and cognitive function in mild to moderate Alzheimer's disease based on quantitative susceptibility mapping

Background

Alzheimer's disease (AD) is a complex neurodegenerative disorder characterized by progressively worsening cognitive decline and memory loss. Excessive iron accumulation produces severe cognitive impairment. However, there are no uniform conclusions about changes in brain iron content in AD. This study aimed to investigate the iron content of the deep brain nuclei in AD, and its correlation with cognitive function.

Methods

Thirty-one patients with mild to moderate AD, 17 patients with mild cognitive impairment (MCI), and 20 age-, sex-, and education-matched healthy controls (HC) were collected. The QSM was used to quantify the magnetic susceptibility values of the caudate nucleus, putamen, globus pallidus, substantia nigra, red nucleus, and dentate nucleus, and to analyze the differences that existed between the three groups. As well as the correlation between the magnetic susceptibility values and cognitive function was calculated.

Results

The magnetic susceptibility values of bilateral globus pallidus, left putamen, and bilateral substantia nigra were significantly higher in AD patients than in HC, and the magnetic susceptibility values of the right globus pallidus were significantly higher in AD patients than in MCI (all p < 0.05). The magnetic susceptibility values of the left dentate nucleus in the AD group were negatively correlated with the writing function of the MMSE subitem (r = -0.42, p = 0.020), and the magnetic susceptibility values of the left caudate nucleus and right dentate nucleus were significantly and negatively correlated with the naming function and language function of the MoCA subitem, respectively (r = -0.43, p = 0.019; r = -0.36, p = 0.048).

Conclusion

Magnetic susceptibility values based on QSM correlate with cognitive function are valuable in discriminating AD from MCI and AD from HC.

Validation and comparison of virtual reality and 3D mobile games for cognitive assessment against ACE-III in 82 young participants

Current medical and clinical ecosystem for dementia detection is inadequate for its early detection. Traditional cognitive assessments are introduced after cognitive impairment has begun to disrupt the real-world functioning of the person. Moreover, these tools are paper-pen based and fail to replicate the real-world situations wherein the person ultimately lives, acts and grows. The lack of tools for early detection of dementia, combined with absence of reliable pharmacological cure compound the problems associated with dementia diagnosis and care. Advancement of technology has facilitated early prediction of disease like cancer, diabetes, heart disease, but hardly any such translation has been observed for dementia or cognitive impairment. Given this background, we examine the potential of Virtual Reality (VR) and 3D Mobile-based goal-oriented games for cognitive assessment. We evaluate three games (2 in VR, one in mobile) among 82 young participants (aged 18-28 years) and compare and contrast the game-based results with their Addenbrooke Cognitive Examination (ACE-III) scores. Three main analysis methods are used: Correlative, Z-score and Regression analysis. Positive correlation was observed for ACE-III and game-based scores. Z-scores analysis revealed no difference between the two scores, and stronger statistical significance was found between game scores and cognitive health factors like age, smoking compared to ACE-III. Specific game performances also revealed about real-world traits of participants, like hand-use confusion and direction confusion. Results establish the plausibility of using goal-oriented games for more granular, time-based, and functional cognitive assessment.

Neuronal Vulnerability of the Entorhinal Cortex to Tau Pathology in Alzheimer's Disease

This review delves into the entorhinal cortex (EC) as a central player in the pathogenesis of Alzheimer's Disease (AD), emphasizing its role in the accumulation and propagation of tau pathology. It elucidates the multifaceted functions of the EC, encompassing memory formation, spatial navigation, and olfactory processing, while exploring how disruptions in these processes contribute to cognitive decline in AD. The review discusses the intricate interplay between tau pathology and EC vulnerability, highlighting how alterations in neuronal firing patterns and synaptic function within the EC exacerbate cognitive impairments. Furthermore, it elucidates how specific neuronal subtypes within the EC exhibit differential susceptibility to tau-induced damage, contributing to disease progression. Early detection methods, such as imaging techniques and assessments of EC blood flow, are examined as potential tools for identifying tau pathology in the preclinical stages of AD. These approaches offer promise for improving diagnostic accuracy and enabling timely intervention. Therapeutic strategies targeting tau pathology within the EC are explored, including the clearance of pathological tau aggregates and the inhibition of tau aggregation processes. By understanding the molecular and cellular mechanisms underlying EC vulnerability, researchers can develop more targeted and effective interventions to slow disease progression. The review underscores the importance of reliable biomarkers to assess disease progression and therapeutic efficacy in clinical trials targeting the EC. Ultimately, it aims to contribute to the development of more effective management strategies for AD, emphasizing the translation of research findings into clinical practice to address the growing societal burden of the disease.

Linking the neural signature of response time variability to Alzheimer's disease pathology and cognitive functioning

Promising evidence has suggested potential links between mind-wandering and Alzheimer's disease (AD). Yet, older adults with diagnosable neurocognitive disorders show reduced meta-awareness, thus questioning the validity of probe-assessed mind-wandering in older adults. In prior work, we employed response time variability as an objective, albeit indirect, marker of mind-wandering to identify patterns of functional connectivity that predicted mind-wandering. In the current study, we evaluated the association of this connectome-based, mind-wandering model with cerebral spinal fluid (CSF) p-tau/Aβ 42 ratio in 289 older adults from the Alzheimer's Disease NeuroImaging Initiative (ADNI). Moreover, we examined if this model was similarly associated with individual differences in composite measures of global cognition, episodic memory, and executive functioning. Edges from the high response time variability model were significantly associated with CSF p-tau/Aβ ratio. Furthermore, connectivity strength within edges associated with high response time variability was negatively associated with global cognition and episodic memory functioning. This study provides the first empirical support for a link between an objective neuromarker of mind-wandering and AD pathophysiology. Given the observed association between mind-wandering and cognitive functioning in older adults, interventions targeted at reducing mind-wandering, particularly before the onset of AD pathogenesis, may make a significant contribution to the prevention of AD-related cognitive decline.

Intranasal insulin effect on cognitive and/or memory impairment: a systematic review and meta-analysis

Background: Cognitive impairment, characterized by deficits in cognitive functions and loss of delayed and immediate recall, disproportionately affects individuals aged 65 years and older, particularly those with comorbid cardiovascular conditions such as hypertension and diabetes mellitus. Objective: This study aimed to investigate the potential association between intranasal insulin and cognitive and/or memory impairment, with a specific focus on delayed and immediate recall, considering the rising prevalence of cognitive disorders in the aging population. Methodology: Employing a rigorous systematic approach, we conducted a thorough search of MEDLINE, Scopus, the Cochrane database, and Web of Science from inception to November 23, 2022, identifying relevant randomized clinical trials. Our analyses encompassed three key aspects: (i) assessing the impact of intranasal insulin on cognitive impairment, (ii) evaluating its effect on delayed recall, and (iii) examining its influence on immediate recall. Results: Five studies meeting the inclusion criteria were included. The results underscored a statistically significant effect of intranasal insulin on delayed memory (effect size: 1.37; 95% CI: 0.65 to 2.09) and overall cognition (effect size: 0.58; 95% CI: 0.08 to 1.08). However, no statistically significant effect was observed for immediate memory (effect size: 0.48; 95% CI: -0.00 to 0.96). Conclusions: This study provides compelling evidence supporting the significance and efficacy of intranasal insulin in enhancing delayed recall and overall cognition. The observed effects hold promise for potential therapeutic interventions in addressing cognitive deficits associated with aging and comorbid conditions. The findings emphasize the need for further research to elucidate the underlying mechanisms and optimize the application of intranasal insulin in cognitive enhancement strategies.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11571-024-10138-5.

Associations of cerebrovascular disease and Alzheimer's disease pathology with cognitive decline: Analysis of the National Alzheimer's Coordinating Center Uniform Data Set

Cerebrovascular disease (CVD) and Alzheimer's disease (AD) often co-occur and may impact specific cognitive domains. This study's goal was to determine effects of CVD and AD burden on cross-sectional and longitudinal executive function (EF) and memory in older adults. Longitudinally followed participants from the National Alzheimer Coordinating Center database (n = 3342) were included. Cognitive outcomes were EF and memory composite scores. Baseline CVD presence was defined by moderate-to-severe white matter hyperintensities or lacunar infarct on MRI. Baseline AD pathology was defined by amyloid positivity via PET or CSF. Linear mixed models examined effects of CVD, AD, and time on cognitive outcomes, controlling for sex, education, baseline age, MoCA score, and total number of study visits. At baseline, CVD associated with lower EF (p < 0.001), while AD associated with lower EF and memory (ps < 0.001). Longitudinally only AD associated with faster declines in memory and EF (ps < 0.001). These results extend our understanding of CVD and AD pathology, highlighting that CVD does not necessarily indicate accelerated decline.

Histidine-containing dipeptide supplementation improves delayed recall: a systematic review and meta-analysis

CONTEXT

Histidine-containing dipeptides (carnosine, anserine, beta-alanine and others) are found in human muscle tissue and other organs like the brain. Data in rodents and humans indicate that administration of exogenous carnosine improved cognitive performance. However, RCTs results vary.

OBJECTIVES

To perform a systematic review and meta-analysis of randomized controlled trials (RCTs) of histidine-containing dipeptide (HCD) supplementation on cognitive performance in humans to assess its utility as a cognitive stabiliser.

DATA SOURCES

OVID Medline, Medline, EBM Reviews, Embase, and Cumulative Index to Nursing and Allied Health Literature databases from 1/1/1965 to 1/6/2022 for all RCT of HCDs were searched.

DATA EXTRACTION

2653 abstracts were screened, identifying 94 full-text articles which were assessed for eligibility. Ten articles reporting the use of HCD supplementation were meta-analysed.

DATA ANALYSIS

The random effects model has been applied using the DerSimonian-Laird method. HCD treatment significantly increased performance on Wechsler Memory Scale (WMS) -2 Delayed recall (Weighted mean difference (WMD) (95% CI (CI)) = 1.5 (0.6, 2.5), P < .01). Treatment with HCDs had no effect on Alzheimer's Disease Assessment Scale-Cognitive (WMD (95% CI) = -0.2 (-1.1, 0.7), P = .65, I2 = 0%), Mini-Mental State Examination (WMD (95% CI) = 0.7 (-0.2, 1.5), P = .14, I2 = 42%), The Wechsler Adult Intelligence Scale (WAIS) Digit span Backward (WMD (95% CI) = 0.1 (-0.3, 0.5), P = .51, I2 = 0%), WAIS digit span Forward (WMD (95% CI) = 0.0 (-0.3, 0.4), P = .85, I2 = 33%) and the WMS-1 Immediate recall (WMD (95% CI) = .7 (-.2, 1.5), P = .11, I2 = 0%). The effect on delayed recall remained in subgroup meta-analysis performed on studies of patients without mild cognitive impairment (MCI), and in those without MCI where average age in the study was above 65.

CONCLUSION

HCD, supplementation improved scores on the Delayed recall examination, a neuropsychological test affected early in Alzheimer's disease. Further studies are needed in people with early cognitive impairment with longer follow-up duration and standardization of carnosine doses to delineate the true effect.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42017075354.

HMGCR Inhibitor Restores Mitochondrial Dynamics by Regulating Signaling Cascades in a Rodent Alzheimer's Disease Model

Atorvastatin an HMGCR inhibitor may play a role in enhancing spatial and long-term memory and combating anxious behavior deficits induced by Aβ1-42. Behavioral deficit studies, immunoblotting for the antioxidant/apoptotic protein expression, flow cytometry (FACS) for mitochondrial ROS, membrane potential (▲ψm), and histopathological alterations were performed against Aβ1-42 toxicity. Aβ1-42 was infused directly into the brain through i.c.v for the establishment of the AD model. Atorvastatin (ATOR) was administered orally and was used to treat AD in adult male Wistar rats aged between 200 and 250 g. We confirmed that ATOR administration significantly attenuates the Aβ1-42-induced cognitive decline targeted mitochondrial-mediated age-dependent disease progression. Nrf2 stabilizes to interact SOD2 antioxidant enzyme, allowing transcriptional activity by the steep increase in ▲ψm and a reduction in ROS by activating mitochondrial superoxide scavenger and Nrf2-dependent pathway. These findings confirmed that ATOR has the potential efficacy to modulate the interference in cognitive decline induced by Aβ1-42.

The effects of APOE4 and familial Alzheimer's disease mutations on free fatty acid profiles in mouse brain are age- and sex-dependent

APOE4 encoding apolipoprotein (Apo)E4 is the strongest genetic risk factor for Alzheimer's disease (AD). ApoE is key in intercellular lipid trafficking. Fatty acids are essential for brain integrity and cognitive performance and are implicated in neurodegeneration. We determined the sex- and age-dependent effect of AD and APOE4 on brain free fatty acid (FFA) profiles. FFA profiles were determined by LC-MS/MS in hippocampus, cortex, and cerebellum of female and male, young (≤3 months) and older (>5 months), transgenic APOE3 and APOE4 mice with and without five familial AD (FAD) mutations (16 groups; n = 7-10 each). In the different brain regions, females had higher levels than males of either saturated or polyunsaturated FFAs or both. In the hippocampus of young males, but not of older males, APOE4 and FAD each induced 1.3-fold higher levels of almost all FFAs. In young and older females, FAD and to a less extent APOE4-induced shifts among saturated, monounsaturated, and polyunsaturated FFAs without affecting total FFA levels. In cortex and cerebellum, APOE4 and FAD had only minor effects on individual FFAs. The effects of APOE4 and FAD on FFA levels and FFA profiles in the three brain regions were strongly dependent of sex and age, particularly in the hippocampus. Here, most FFAs that are affected by FAD are similarly affected by APOE4. Since APOE4 and FAD affected hippocampal FFA profiles already at young age, these APOE4-induced alterations may modulate the pathogenesis of AD.

CSF proteomic profiles of neurodegeneration biomarkers in Alzheimer's disease

INTRODUCTION

We aimed to unravel the underlying pathophysiology of the neurodegeneration (N) markers neurogranin (Ng), neurofilament light (NfL), and hippocampal volume (HCV), in Alzheimer's disease (AD) using cerebrospinal fluid (CSF) proteomics.

METHODS

Individuals without dementia were classified as A+ (CSF amyloid beta [Aβ]42), T+ (CSF phosphorylated tau181), and N+ or N- based on Ng, NfL, or HCV separately. CSF proteomics were generated and compared between groups using analysis of covariance.

RESULTS

Only a few individuals were A+T+Ng-. A+T+Ng+ and A+T+NfL+ showed different proteomic profiles compared to A+T+Ng- and A+T+NfL-, respectively. Both Ng+ and NfL+ were associated with neuroplasticity, though in opposite directions. Compared to A+T+HCV-, A+T+HCV+ showed few proteomic changes, associated with oxidative stress.

DISCUSSION

Different N markers are associated with distinct neurodegenerative processes and should not be equated. N markers may differentially complement disease staging beyond amyloid and tau. Our findings suggest that Ng may not be an optimal N marker, given its low incongruency with tau pathophysiology.

HIGHLIGHTS

In Alzheimer's disease, neurogranin (Ng)+, neurofilament light (NfL)+, and hippocampal volume (HCV)+ showed differential protein expression in cerebrospinal fluid. Ng+ and NfL+ were associated with neuroplasticity, although in opposite directions. HCV+ showed few proteomic changes, related to oxidative stress. Neurodegeneration (N) markers may differentially refine disease staging beyond amyloid and tau. Ng might not be an optimal N marker, as it relates more closely to tau.

Impact of Apolipoprotein E ε4 in Alzheimer's Disease: A Meta-Analysis of Voxel-Based Morphometry Studies

BACKGROUND AND PURPOSE

Alzheimer's disease (AD) is the most-prevalent form of dementia and imposes substantial burdens at the personal and societal levels. The apolipoprotein E (APOE) ε4 allele is a genetic factor known to increase AD risk and exacerbate brain atrophy and its symptoms. We aimed to provide a comprehensive review of the impacts of APOE ε4 on brain atrophy in AD as well as in mild cognitive impairment (MCI) as a transitional stage of AD.

METHODS

We performed a coordinate-based meta-analysis of voxel-based morphometry studies to compare gray-matter atrophy patterns between carriers and noncarriers of APOE ε4. We obtained coordinate-based structural magnetic resonance imaging data from 1,135 individuals who met our inclusion criteria among 12 studies reported in PubMed and Google Scholar.

RESULTS

We found that atrophy of the hippocampus and parahippocampus was significantly greater in APOE ε4 carriers than in noncarriers, especially among those with AD and MCI, while there was no significant atrophy in these regions in healthy controls who were also carriers.

CONCLUSIONS

The present meta-analysis has highlighted the significant link between the APOE ε4 allele and hippocampal atrophy in both AD and MCI, which emphasizes the critical influence of the allele on neurodegeneration, especially in the hippocampus. These findings improve the understanding of AD pathology, potentially facilitating progress in early detection, targeted interventions, and personalized care strategies for individuals at risk of AD who carry the APOE ε4 allele.

Modern scores for traditional tests - Review of the diagnostic potential of scores derived from word list learning tests in mild cognitive impairment and early Alzheimer's Disease

Episodic memory impairment is one of the early hallmarks in Alzheimer's Disease. In the clinical diagnosis and research, episodic memory impairment is typically assessed using word lists that are repeatedly presented to and recalled by the participant across several trials. Until recently, total learning scores, which consist of the total number of words that are recalled by participants, were almost exclusively used for diagnostic purposes. The present review aims at summarizing evidence on additional scores derived from the learning trials which have recently been investigated more frequently regarding their diagnostic potential. These scores reflect item acquisition, error frequencies, strategy use, intertrial fluctuations, and recall consistency. Evidence was summarized regarding the effects of clinical status on these scores. Preclinical, mild cognitive impairment and mild Alzheimer's Disease stages were associated with a pattern of reduced item acquisition, more errors, less strategy use, and reduced access of items, indicating slowed and erroneous encoding. Practical implications and limitations of the present research will be discussed.

Modeling APOE ε4 familial Alzheimer's disease in directly converted 3D brain organoids

Brain organoids have become a valuable tool for studying human brain development, disease modeling, and drug testing. However, generating brain organoids with mature neurons is time-intensive and often incomplete, limiting their utility in studying age-related neurodegenerative diseases such as Alzheimer's disease (AD). Here, we report the generation of 3D brain organoids from human fibroblasts through direct reprogramming, with simplicity, efficiency, and reduced variability. We also demonstrate that induced brain organoids from APOE ε4 AD patient fibroblasts capture some disease-specific features and pathologies associated with APOE ε4 AD. Moreover, APOE ε4-induced brain organoids with mutant APP overexpression faithfully recapitulate the acceleration of AD-related pathologies, providing a more physiologically relevant and patient-specific model of familial AD. Importantly, transcriptome analysis reveals that gene sets specific to APOE ε4 patient-induced brain organoids are highly similar to those of APOE ε4 post-mortem AD brains. Overall, induced brain organoids from direct reprogramming offer a promising approach for more efficient and controlled studies of neurodegenerative disease modeling.

Exercise leads to sex-specific recovery of behavior and pathological AD markers following adolescent ethanol exposure in the TgF344-AD model

Introduction

Human epidemiological studies suggest that heavy alcohol consumption may lead to earlier onset of Alzheimer's Disease (AD), especially in individuals with a genetic predisposition for AD. Alcohol-related brain damage (ARBD) during a critical developmental timepoint, such as adolescence, interacts with AD-related pathologies to accelerate disease progression later in life. The current study investigates if voluntary exercise in mid-adulthood can recover memory deficits caused by the interactions between adolescence ethanol exposure and AD-transgenes.

Methods

Male and female TgF344-AD and wildtype F344 rats were exposed to an intragastric gavage of water (control) or 5 g/kg of 20% ethanol (adolescent intermittent ethanol; AIE) for a 2 day on/off schedule throughout adolescence (PD27-57). At 6 months old, rats either remained in their home cage (stationary) or were placed in a voluntary wheel running apparatus for 4 weeks and then underwent several behavioral tests. The number of cholinergic neurons in the basal forebrain and measure of neurogenesis in the hippocampus were assessed.

Results

Voluntary wheel running recovers spatial working memory deficits selectively in female TgF344-AD rats exposed to AIE and improves pattern separation impairment seen in control TgF344-AD female rats. There were sex-dependent effects on brain pathology: Exercise improves the integration of recently born neurons in AIE-exposed TgF344-AD female rats. Exercise led to a decrease in amyloid burden in the hippocampus and entorhinal cortex, but only in male AIE-exposed TgF344-AD rats. Although the number of basal forebrain cholinergic neurons was not affected by AD-transgenes in either sex, AIE did reduce the number of basal forebrain cholinergic neurons in female rats.

Discussion

These data provide support that even after symptom onset, AIE and AD related cognitive decline and associated neuropathologies can be rescued with exercise in unique sex-specific ways.