Therapies for Prevention and Treatment of Alzheimer's Disease

Novel insights into famotidine as a GSK-3β inhibitor: An explorative study in aluminium chloride-induced Alzheimer's disease rat model

Alzheimer's disease (AD), a chronic neurodegenerative disease, presents a substantial global health challenge. This study explored the potential therapeutic role of famotidine, a histamine (H2) receptor antagonist, as a glycogen synthase kinase-3β (GSK-3β) inhibitor in the context of AD induced by aluminium chloride (AlCl3) in a rat model. The intricate relationship between GSK-3β dysregulation and AD pathogenesis, particularly in amyloid-β (Aβ) production, formed the basis for investigating famotidine's efficacy. Molecular modelling revealed famotidine's efficient binding to GSK-3β, suggesting inhibitory potential. In behavioural assessments, famotidine-treated groups exhibited dose-dependent improvements in Morris Water Maze, Novel Object Recognition, and Y-Maze tests, comparable to the standard Rivastigmine tartrate group. Biochemical analyses showed that famotidine inhibits acetylcholinesterase, decreases lipid peroxidation, increases antioxidant activity, and mitigates oxidative stress. Moreover, famotidine significantly lowered the levels of GSK-3β, IL-6, and Aβ(1-42). The neuroprotective effects of famotidine were further supported by histopathological analysis. This comprehensive investigation underscores famotidine's potential as a GSK-3β inhibitor, providing insights into its therapeutic impact on AD induced by AlCl3. The study offers a promising avenue for repurposing famotidine due to its established safety profile and widespread availability, highlighting its potential in addressing the formidable challenge of AD.

A review on synthetic inhibitors of dual-specific tyrosine phosphorylation-regulated kinase 1A (DYRK1A) for the treatment of Alzheimer's disease (AD)

Alzheimer's disease (AD) is a complex disorder that is influenced by a number of variables, such as age, gender, environmental factors, disease, lifestyle, infections, and many more. The main characteristic of AD is the formation of amyloid plaque and neurofibrillary tangles (NFT), which are caused by various reasons such as inflammation, impairment of neurotransmitters, hyperphosphorylation of tau protein, generation of toxic amyloid beta (Aβ) 40/42, oxidative stress, etc. Protein kinases located in chromosome 21, namely dual-specific tyrosine phosphorylation-regulated kinase 1A (DYRK1A), play an essential role in the pathogenesis of AD. DYRK1A stimulates the Aβ peptide aggregation and phosphorylation of tau protein to generate the NFT formation that causes neurodegeneration. Thus, DYRK1A is associated with AD, and inhibition of DYRK1A has the potential to treat AD. In this review, we discussed the pathophysiology of AD, various factors responsible for AD, and the role of DYRK1A in AD. We have also discussed the latest therapeutic potential of DYRK1A inhibitors for neurogenerative disease, along with their structure-activity relationship (SAR) studies. This article provides valuable information for guiding the future discovery of novel and target-specific DYRK1A inhibitors over other kinases and their structural optimization to treat AD.

Inflammatory signaling pathways in Alzheimer's disease: Mechanistic insights and possible therapeutic interventions

The complex pathophysiology of Alzheimer's disease (AD) poses challenges for the development of therapies. Recently, neuroinflammation has been identified as a key pathogenic mechanism underlying AD, while inflammation has emerged as a possible target for the management and prevention of AD. Several prior studies have demonstrated that medications modulating neuroinflammation might lessen AD symptoms, mostly by controlling neuroinflammatory signaling pathways such as the NF-κB, MAPK, NLRP3, etc, and their respective signaling cascade. Moreover, targeting these inflammatory modalities with inhibitors, natural products, and metabolites has been the subject of intensive research because of their anti-inflammatory characteristics, with many studies demonstrating noteworthy pharmacological capabilities and potential clinical applications. Therefore, targeting inflammation is considered a promising strategy for treating AD. This review comprehensively elucidates the neuroinflammatory mechanisms underlying AD progression and the beneficial effects of inhibitors, natural products, and metabolites in AD treatment.

Molecular mechanism underlying effect of D93 and D289 protonation states on inhibitor-BACE1 binding: exploration from multiple independent Gaussian accelerated molecular dynamics and deep learning

BACE1 has been regarded as an essential drug design target for treating Alzheimer's disease (AD). Multiple independent Gaussian accelerated molecular dynamics simulations (GaMD), deep learning (DL), and molecular mechanics general Born surface area (MM-GBSA) method are integrated to elucidate the molecular mechanism underlying the effect of D93 and D289 protonation on binding of inhibitors OV6 and 4B2 to BACE1. The GaMD trajectory-based DL successfully identifies significant function domains. Dynamic analysis shows that the protonation of D93 and D289 strongly affects the structural flexibility and dynamic behaviour of BACE1. Free energy landscapes indicate that inhibitor-bound BACE1s have more conformational states in the protonated states than the wild-type (WT) BACE1, and show more binding poses of inhibitors. Binding affinities calculated using the MM-GBSA method indicate that the protonation of D93 and D289 highly disturbs the binding ability of inhibitors to BACE1. In addition, the protonation of two residues significantly affects the hydrogen bonding interactions (HBIs) of OV6 and 4B2 with BACE1, altering their binding activity to BACE1. The binding hot spots of BACE1 recognized by residue-based free energy estimations provide rational targeting sites for drug design towards BACE1. This study is anticipated to provide theoretical aids for drug development towards treatment of AD.

Breaking Barriers in Alzheimer's Disease: the Role of Advanced Drug Delivery Systems

Alzheimer's disease (AD), characterized by cognitive impairment, brain plaques, and tangles, is a global health concern affecting millions. It involves the build-up of amyloid-β (Aβ) and tau proteins, the formation of neuritic plaques and neurofibrillary tangles, cholinergic system dysfunction, genetic variations, and mitochondrial dysfunction. Various signaling pathways and metabolic processes are implicated in AD, along with numerous biomarkers used for diagnosis, risk assessment, and research. Despite these, there is no cure or effective treatment for AD. It is critically important to address this immediately to develop novel drug delivery systems (NDDS) capable of targeting the brain and delivering therapeutic agents to modulate the pathological processes of AD. This review summarizes AD, its pathogenesis, related signaling pathways, biomarkers, conventional treatments, the need for NDDS, and their application in AD treatment. It also covers preclinical, clinical, and ongoing trials, patents, and marketed AD formulations.

Study on correlation between perioperative cognitive function and nutritional status in elderly patients with gastric cancer

OBJECTIVE

To investigate the cognitive function and nutritional status of elderly patients with gastric cancer during perioperative period, and to analyze their correlation.

METHODS

Aged patients undergoing gastric cancer surgery in The Affiliated Cancer Hospital of Shandong First Medical University from March to October 2021 were selected as the subjects of this study. The monitoring data of cognitive function and nutritional status were retrospectively analyzed from 1 to 3 days before surgery, 1 and 3 days after surgery, 7 days after surgery (before discharge) and 30 days after surgery to analyze the correlation between cognitive function and nutritional status in elderly patients with gastric cancer.

RESULTS

the incidence of mild cognitive impairment in elderly patients with gastric cancer was 52.43 %, the visual space of the two groups' (mild cognitive impairment) ability of execution, name, attention, language, abstract thinking, delayed memory and cognitive function scores were lower than 1 set of directional force (cognitive function in normal group), statistically significant difference (P < 0.05). The nutritional status of elderly patients with gastric cancer was lower than that of healthy elderly group at the same period (P < 0.05). The scores of visual spatial executive function, name, attention, delayed memory, orientation and total score of cognitive function in elderly gastric cancer patients were positively correlated with nutritional status (P < 0.05).

CONCLUSIONS

The cognitive function and nutritional status of elderly patients with gastric cancer are both in a low state during treatment and a higher level of cognitive function can help patients maintain a more correct nutritional cognition, and the nutritional status of patients will be relatively better. There is a positive correlation between cognitive function and nutritional status in elderly patients with gastric cancer, which should be paid attention to in the treatment.

Discovery of a novel pyrido[1,2-a]thiazolo[5,4-d]pyrimidinone derivatives with excellent potency against acetylcholinesterase

As mimetic compounds of the natural alkaloid mackinazolinone, forty pyrido[1,2-a]thiazolo[5,4-d] pyrimidinone were designed and synthesized from a bioisosterism approach. The structure of these compounds was confirmed through analysis using 1H NMR, 13C NMR, and HRMS techniques. All the compounds were evaluated for their anticholinesterase activities and cytotoxicity on normal cells (293 T) by the Ellman method and methyl thiazolyl tetrazolium (MTT) method in vitro. and the structure-activity relationships (SARs) were summarized. The results showed that most of the compounds effectively inhibited acetylcholinesterase (AChE) in the micromolar range with weak cytotoxicity. Compound 7o exhibited the best inhibitory activity against AChE, displaying an IC50 values of 1.67 ± 0.09 µM and an inhibitory constant Ki of 11.31 µM as a competitive inhibitor to AChE. Molecular docking indicated that compound 7o may bind to AChE via hydrogen bond and π-π stacking. Further molecular dynamics (MD) simulations indicated a relatively low binding free energy (- 27.91 kJ·mol-1) of compound 7o with AChE. In summary, the collective findings suggested that 7o was promising as a potential novel drug candidate worthy of further investigation for the treatment of Alzheimer's disease.

Gene therapy: an alternative to treat Alzheimer's disease

Alzheimer's disease (AD), a neuro-degenerative disease that primarily affects the elderly, is a worldwide phenomenon. Loss of memory, cognitive decline, behavioural changes, and many other signs are used to classify it. Various hypotheses that may contribute to Alzheimer's disease have been found during decades of survey, including tau theory, the amyloid theory, the cholinergic hypothesis, and the oxidative stress hypothesis. According to some theories, the two leading causes of AD are the accumulation of amyloid beta plaque and development of NFTs in the brain. The hippocampus and cerebral cortex are the primary sites where amyloid beta plaques gather in the body. NFT formation in the brain impairs the brain's neurons' potential of signalling. According to the age at which it manifests in a person, there are two subtypes of AD: 'LOAD (Late Onset Alzheimer's Disease)' and 'EOAD (Early Onset Alzheimer's Disease)'. Long-term research into AD treatment has resulted in the introduction of some medications that provided symptomatic relief to patients but did not alter the disease's pathophysiology, like cholinesterase inhibitors, inhibitors of tau aggregation, and monoclonal antibodies to Aβ aggregation. Even though the medications did not halt the progression of AD, researchers did not discontinue their work, which lead to the introduction of gene therapy - a recently created cutting-edge method of delivering genes to target sites where they can express the intended functionalities. Viral or non-viral vectors could be used to deliver the gene, each with advantages and limitations of their own. Gene therapy is proven to be a potential disease-modifying treatment for AD. This article discusses about gene therapy, its merits and demerits and the various ways of gene delivery. Additionally, it focuses on AD as the target for treatment through gene therapy, the pathophysiology of AD, and the multiple targets for gene therapy in the treatment of AD.

The effect of retirement on physical and mental health in China: a nonparametric fuzzy regression discontinuity study

BACKGROUND

With the rapid aging of the domestic population, China has a strong incentive to increase the statutory retirement age. How retirement affects the health of the elderly is crucial to this policymaking. The health consequences of retirement have been debated greatly. This study aims to investigate the effects of retirement on physical and mental health among Chinese elderly people.

METHODS

The data we use in this study comes from four waves (2011, 2013, 2015, and 2018) of the Harmonized China Health and Retirement Longitudinal Study (Harmonized CHARLS), a prospective cohort. We use the nonparametric fuzzy regression discontinuity design to estimate the effects of retirement on physical and mental health. We test the robustness of our results with respect to different bandwidths, kernel functions, and polynomial orders. We also explore the heterogeneity across gender and education.

RESULTS

Results show that retirement has an insignificant effect on a series of physical and mental health outcomes, with and without adjusting several sociodemographic variables. Heterogeneity exists regarding gender and education. Although stratified analyses indicate that the transition from working to retirement leaves minimal effects on males and females, the effects go in the opposite direction. This finding holds for low-educated and high-educated groups for health outcomes including depression and cognitive function. Most of the results are stable with respect to different bandwidths, kernel functions, and polynomial orders.

CONCLUSIONS

Our results suggest that it is possible to delay the statutory retirement age in China as retirement has insignificant effects on physical and mental health. However, further research is needed to assess the long-term effect of retirement on health.

Protective Effects of Heat-Killed Ruminococcus albus against β-Amyloid-Induced Apoptosis on SH-SY5Y Cells

A high level of β-amyloid (Aβ) in the brains of patients with Alzheimer's disease (AD) generates reactive oxygen species that induce neuronal death and DNA damage. The interaction between the gut microbiota and brain health has attracted attention in recent years. Heat-killed Ruminococcus albus (hkRA) reportedly protects neurons against damage induced by oxidative stress. However, whether hkRA can inhibit Aβ-induced apoptosis and thus alleviate AD remains unclear. Hence, we aimed to evaluate the protective effects of hkRA against Aβ-induced apoptosis on the human neuroblastoma SH-SY5Y cell. HkRA treatment (108 cells/ml) significantly decreased the Aβ-induced cytotoxicity and DNA damage in the SH-SY5Y cells. It also showed a significant increase of the bax/bcl-2 ratio in the Aβ-treated SH-SY5Y cells. Moreover, hkRA treatment stimulated the expression of antioxidation-related genes HO-1, Nrf2, and PKC-δ and increased the expression of brain-derived neurotrophic factor (BDNF). Meanwhile, it significantly decreased the activity of caspase-3 and protein expression of cleaved caspase-3 in the Aβ-treated SH-SY5Y cells. Additionally, the protein levels of mitochondrial and cytosolic cytochrome c increased and decreased, respectively, in the cells. These results suggest that hkRA protects human neuroblastoma cells from Aβ-induced apoptosis and oxidative stress. Thus, hkRA may be developed into a health-promoting paraprobiotic (the inactivated microbial cells of probiotics) for patients with AD.

Effects of remote combine exercise-music training on physical and cognitive performance in patients with Alzheimer's disease: a randomized controlled trial

Introduction

This study aimed to investigate the effects of combined remote music and exercise training on the cognitive, psychological, and physical function of patients with Alzheimer's disease (AD).

Methods

Forty-one AD patients were randomly allocated to three groups, including control (C), training (T), and training with music (TM) groups. Participants were evaluated by cognitive and performance test batteries before and after the interventions. Both experimental groups performed 36 remote workouts in 3 months online via WhatsApp video call individually with the trainer. Training included simple and varied movements of all physical indicators. The number of sets began with two sets and progressively increased to one set every month, 5-10 repetitions per set. The overload was applied by reducing the break between sets every week. The TM group performed the same exercises while listening to Mozart and traditional Iranian songs.

Results

We observed a significant main, group, time, and interaction effect on Romberg (ηp2:0.72), 30 s chair sit and stand (ηp2:0.75), and walking on steppe test (ηp2:0.63). Furthermore, there was a significant main time and interaction effect on push-ups (ηp2:0.43), sit and reach (ηp2:0.64), and MMSE (ηp2:0.76). In all variables, two experimental groups demonstrated substantial improvements than the C group (p < 0.01). In addition, the TM group (27.8%) showed a significant improvement compared to the C group (-6.4%) and the T group (12.2%) in MMSE.

Conclusion

Combined remote training with listening to music as adjuvant treatment is an appropriate item to improve the cognitive and physical performance of Alzheimer's patients, especially during the COVID-19 pandemic.

Olfactory Dysfunction Associated with Cognitive Decline in an Elderly Population

BACKGROUND

In many neurological disorders, including Alzheimer disease, early olfactory dysfunction is observed.

OBJECTIVE

In order to determine if deficits in olfactory memory are present in the elderly and if olfactory dysfunction correlates with cognitive impairment in the aging population, olfactory testing has been done on seniors from the NuAge cohort accepting to participate in the Olfactory Response Cognition and Aging (ORCA) secondary sub-study. The t-Mini Mental Statement Examination and the Telephone Interview for Cognitive Status tests were done to assess cognition levels.

RESULTS

Overall, 94% of the ORCA cohort displayed olfactory dysfunction. Deficits in olfactory memory were also present. A correlation was observed between olfactory function and cognitive test scores. Moreover, in women who smoked, there was an association between olfactory memory and cognitive scores.

CONCLUSION

Our results suggest that olfactory dysfunction may predict impending cognitive decline and highlights the need for olfactory training in seniors to improve olfaction and overall well-being.

Regulation of neuroinflammation in Alzheimer's disease via nanoparticle-loaded phytocompounds with anti-inflammatory and autophagy-inducing properties

BACKGROUND

Alzheimer's disease (AD) is characterized by neuroinflammation linked to amyloid β (Aβ) aggregation and phosphorylated tau (τ) protein in neurofibrillary tangles (NFTs). Key elements in Aβ production and NFT assembly, like γ-secretase and p38 mitogen-activated protein kinase (p38MAPK), contribute to neuroinflammation. In addition, impaired proteosomal and autophagic pathways increase Aβ and τ aggregation, leading to neuronal damage. Conventional neuroinflammation drugs have limitations due to unidirectional therapeutic approaches and challenges in crossing the Blood-Brain Barrier (BBB). Clinical trials for non-steroidal anti-inflammatory drugs (NSAIDs) and other therapeutics remain uncertain. Novel strategies addressing the complex pathogenesis and BBB translocation are needed to effectively tackle AD-related neuroinflammation.

PURPOSE

The current scenario demands for a much-sophisticated theranostic measures which could be achieved via customized engineering and designing of novel nanotherapeutics. As, these therapeutics functions as a double edge sword, having the efficiency of unambiguous targeting, multiple drug delivery and ability to cross BBB proficiently.

METHODS

Inclusion criteria involve selecting recent, English-language studies from the past decade (2013-2023) that explore the regulation of neuroinflammation in neuroinflammation, Alzheimer's disease, amyloid β, tau protein, nanoparticles, autophagy, and phytocompounds. Various study types, including clinical trials, experiments, and reviews, were considered. Exclusion criteria comprised non-relevant publication types, studies unrelated to Alzheimer's disease or phytocompounds, those with methodological flaws, duplicates, and studies with inaccessible data.

RESULTS

In this study, polymeric nanoparticles loaded with specific phytocompounds and coated with an antibody targeting the transferrin receptor (anti-TfR) present on BBB. Thereafter, the engineered nanoparticles with the ability to efficiently traverse the BBB and interact with target molecules within the brain, could induce autophagy, a cellular process crucial for neuronal health, and exhibit potent anti-inflammatory effects. Henceforth, the proposed combination of desired phytocompounds, polymeric nanoparticles, and anti-TfR coating presents a promising approach for targeted drug delivery to the brain, with potential implications in neuroinflammatory conditions such as Alzheimer's disease.

A Potential Role for the Ketogenic Diet in Alzheimer's Disease Treatment: Exploring Pre-Clinical and Clinical Evidence

Given the remarkable progress in global health and overall quality of life, the significant rise in life expectancy has become intertwined with the surging occurrence of neurodegenerative disorders (NDs). This emerging trend is poised to pose a substantial challenge to the fields of medicine and public health in the years ahead. In this context, Alzheimer's disease (AD) is regarded as an ND that causes recent memory loss, motor impairment and cognitive deficits. AD is the most common cause of dementia in the elderly and its development is linked to multifactorial interactions between the environment, genetics, aging and lifestyle. The pathological hallmarks in AD are the accumulation of β-amyloid peptide (Aβ), the hyperphosphorylation of tau protein, neurotoxic events and impaired glucose metabolism. Due to pharmacological limitations and in view of the prevailing glycemic hypometabolism, the ketogenic diet (KD) emerges as a promising non-pharmacological possibility for managing AD, an approach that has already demonstrated efficacy in addressing other disorders, notably epilepsy. The KD consists of a food regimen in which carbohydrate intake is discouraged at the expense of increased lipid consumption, inducing metabolic ketosis whereby the main source of energy becomes ketone bodies instead of glucose. Thus, under these dietary conditions, neuronal death via lack of energy would be decreased, inasmuch as the metabolism of lipids is not impaired in AD. In this way, the clinical picture of patients with AD would potentially improve via the slowing down of symptoms and delaying of the progression of the disease. Hence, this review aims to explore the rationale behind utilizing the KD in AD treatment while emphasizing the metabolic interplay between the KD and the improvement of AD indicators, drawing insights from both preclinical and clinical investigations. Via a comprehensive examination of the studies detailed in this review, it is evident that the KD emerges as a promising alternative for managing AD. Moreover, its efficacy is notably enhanced when dietary composition is modified, thereby opening up innovative avenues for decreasing the progression of AD.

Novel harmine derivatives as potent acetylcholinesterase and amyloid beta aggregation dual inhibitors for management of Alzheimer's disease

In this study, a series of potential ligands for the treatment of AD were synthesised and characterised as novel harmine derivatives modified at position 9 with benzyl piperazinyl. In vitro studies revealed that the majority of the derivatives exhibited moderate to potent inhibition against hAChE and Aβ1 - 42 aggregation. Notably, compounds 13 and 17d displayed potent drug - likeness and ADMET properties, demonstrating remarkable inhibitory activities towards AChE (IC50 = 58.76 nM and 89.38 nM, respectively) as well as Aβ aggregation (IC50 = 9.31 μM and 13.82 μM, respectively). More importantly, compounds 13 and 17d showed exceptional neuroprotective effects against Aβ1 - 42-induced SH - SY5Y damage, while maintaining low toxicity in SH - SY5Y cells. Further exploration of the mechanism through kinetic studies and molecular modelling confirmed that compound 13 could interact with both the CAS and the PAS of AChE. These findings suggested that harmine derivatives hold great potential as dual - targeted candidates for treating AD.

Association between serum lipid levels and lower-extremity functions in older adults with and without Alzheimer's dementia in South Korea: A cross-sectional analysis

PURPOSE

Older adults with Alzheimer's dementia (AD) experience lower-extremity dysfunction. High serum lipid levels are a risk factor for AD. We investigated the association between serum lipid levels and lower-extremity function in older individuals with and without AD.

METHODS

In this cross-sectional study, we enrolled 33,185 senior citizens (aged 66 years) who participated in the National Geriatric Screening Program, sampled from the Korean National Health Insurance Service-National Health Screening Cohort Database, between 2009 and 2015. Participants were dichotomized into 1) an AD group comprising individuals with the International Classification of Diseases, Tenth Revision, diagnostic codes F00, F00.0-F00.9, and G30, G30.0-G30.9; and 2) a control group comprising individuals without AD. Differences in the Timed Up and Go and One-Leg Standing results among the three levels (low, moderate, and high) of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol were evaluated between the groups. Logistic regression analysis was performed to estimate the odds of gait disorder considering clinical and lifestyle variables.

RESULTS

In participants with low LDL-C levels, increased LDL-C levels correlated with higher gait speed. In the AD group, balancing time with eyes open (BT-EO) was inversely correlated with TG levels in participants with low TG levels. In the control group, BT-EO was negatively correlated with TC levels in participants with low TC levels.

CONCLUSION

Serum lipid levels were significantly correlated with lower-extremity function in participants with and without AD but not with gait disorder in participants with AD.

The Neuroprotective Effects of Dendropanax morbifera Water Extract on Scopolamine-Induced Memory Impairment in Mice

This study investigated the neuroprotective effects of Dendropanax morbifera leaves and stems (DMLS) water extract on scopolamine (SCO)-induced memory impairment in mice. First, we conducted experiments to determine the protective effect of DMLS on neuronal cells. Treatment with DMLS showed a significant protective effect against neurotoxicity induced by Aβ(25-35) or H2O2. After confirming the neuroprotective effects of DMLS, we conducted animal studies. We administered DMLS orally at concentrations of 125, 250, and 375 mg/kg for 3 weeks. In the Y-maze test, SCO decreased spontaneous alternation, but treatment with DMLS or donepezil increased spontaneous alternation. In the Morris water-maze test, the SCO-treated group showed increased platform reach time and decreased swim time on the target platform. The passive avoidance task found that DMLS ingestion increased the recognition index in short-term memory. Furthermore, memory impairment induced by SCO reduced the ability to recognize novel objects. In the Novel Object Recognition test, recognition improved with DMLS or donepezil treatment. In the mouse brain, except for the cerebellum, acetylcholinesterase activity increased in the SCO group and decreased in the DMLS and donepezil groups. We measured catalase and malondialdehyde, which are indicators of antioxidant effectiveness, and found that oxidative stress increased with SCO but was mitigated by DMLS or donepezil treatment. Thus, our findings suggest that ingestion of DMLS restored memory impairment by protecting neuronal cells from Aβ(25-35) or H2O2-induced neurotoxicity, and by reducing oxidative stress.

Fe65-engineered neuronal exosomes encapsulating corynoxine-B ameliorate cognition and pathology of Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the predominant impairment of neurons in the hippocampus and the formation of amyloid plaques, hyperphosphorylated tau protein, and neurofibrillary tangles in the brain. The overexpression of amyloid-β precursor protein (APP) in an AD brain results in the binding of APP intracellular domain (AICD) to Fe65 protein via the C-terminal Fe65-PTB2 interaction, which then triggers the secretion of amyloid-β and the consequent pathogenesis of AD. Apparently, targeting the interaction between APP and Fe65 can offer a promising therapeutic approach for AD. Recently, exosome, a type of extracellular vesicle with diameter around 30-200 nm, has gained much attention as a potential delivery tool for brain diseases, including AD, due to their ability to cross the blood-brain barrier, their efficient uptake by autologous cells, and their ability to be surface-modified with target-specific receptor ligands. Here, the engineering of hippocampus neuron cell-derived exosomes to overexpress Fe65, enabled the development of a novel exosome-based targeted drug delivery system, which carried Corynoxine-B (Cory-B, an autophagy inducer) to the APP overexpressed-neuron cells in the brain of AD mice. The Fe65-engineered HT22 hippocampus neuron cell-derived exosomes (Fe65-EXO) loaded with Cory-B (Fe65-EXO-Cory-B) hijacked the signaling and blocked the natural interaction between Fe65 and APP, enabling APP-targeted delivery of Cory-B. Notably, Fe65-EXO-Cory-B induced autophagy in APP-expressing neuronal cells, leading to amelioration of the cognitive decline and pathogenesis in AD mice, demonstrating the potential of Fe65-EXO-Cory-B as an effective therapeutic intervention for AD.

Repetitive transcranial magnetic stimulation may be superior to drug therapy in the treatment of Alzheimer's disease: A systematic review and Bayesian network meta-analysis

BACKGROUND

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive brain stimulation therapy that is primarily used to treat a variety of neuropsychiatric conditions. Recently, previous research reports stated that rTMS have the characteristics of neurorestorative in Alzheimer's disease (AD). However, the relevant clinical research evidence has not been fully summarized.

METHODS

This article performed a network meta-analysis of individual participant data from eligible studies searched in PubMed, Embase, and the Cochrane Library from inception to March 31, 2022. The drug treatments involved were acetylcholinesterase inhibitors (AChEIs), N-methyl-d-aspartate (NMDA), anti-amyloid-beta (Aβ), and some new targeted therapeutic drugs.

RESULTS

A total of 15, 548 individuals with AD disease in 57 randomized clinical trials (RCTs) were included in this meta-analysis. The results indicated that the patients who received rTMS treatment (standard mean difference [SMD]: 0.65; 95% confidence interval [CI]: 0.22-1.07) had a better MMSE score than placebo. Treatment outcome analysis showed that, compared with multiple pharmacological interventions, rTMS acquired the greatest probability rank with the best cognitive improvement in MMSE score [the surface under the cumulative ranking curve (SUCRA) 93.3%] and ADAS-cog score (SUCRA 86.7%). At the same time, rTMS treatment had the lowest rank in the adverse events (SUCRA 24.1%) except for the placebo group (SUCRA 19.1%).

CONCLUSION

Compared with the current clinical drug treatment, rTMS demonstrated better cognitive function improvement and fewer adverse events in AD patients. Therefore, rTMS shows broad prospects in the treatment of Alzheimer's disease, and it is worth being widely popularized in clinic.

Discovery of myrsinane-type Euphorbia diterpene derivatives through a skeleton conversion strategy from lathyrane diterpene for the treatment of Alzheimer's disease

A series of novel myrsinane-type Euphorbia diterpene derivatives (1-37) were synthesized from the abundant natural lathyrane-type Euphorbia factor L3, using a multi-step chemical process guided by a bioinspired skeleton conversion strategy, with the aim of discovering potential anti-Alzheimer's disease (AD) bioactive lead compounds. The synthesis process involved a concise reductive olefin coupling reaction through an intramolecular Michael addition with a free radical, followed by a visible-light-triggered regioselective cyclopropane ring-opening. The cholinesterase inhibitory and neuroprotective activities of the synthesized myrsinane derivatives were evaluated. Most of the compounds showed moderate to strong potency, highlighting the importance of ester groups in Euphorbia diterpene. In particular, derivative 37 displayed the most potent acetylcholinesterase (AChE) inhibition, with an IC50 value of 8.3 μM, surpassing that of the positive control, tacrine. Additionally, 37 also showed excellent neuroprotective effect against H2O2-induced injury in SH-SY5Y cells, with a cell viability rate of 124.2% at 50 μM, which was significantly higher than that of the model group (viability rate 52.1%). Molecular docking, reactive oxygen species (ROS) analysis, immunofluorescence, and immunoblotting were performed to investigate the mechanism of action of myrsinane derivative 37. The results indicated that derivative 37 may be a promising myrsinane-type multi-functional lead compound for the treatment of Alzheimer's disease. Furthermore, a preliminary SAR analysis was performed to study the acetylcholinesterase inhibitory and neuroprotective activities of these diterpenes.

Apolipoprotein ε in Brain and Retinal Neurodegenerative Diseases

Alzheimer's disease (AD) is the most common form of dementia that remains incurable and has become a major medical, social, and economic challenge worldwide. AD is characterized by pathological hallmarks of senile plaques (SP) and neurofibrillary tangles (NFTs) that damage the brain up to twenty years before a clinical diagnosis is made. Interestingly these pathological features have also been observed in retinal neurodegenerative diseases including age related macular degeneration (ARMD), glaucoma and diabetic retinopathy (DR). An association of AD with these diseases has been suggested in epidemiological studies and several common pathological events and risk factors have been identified between these diseases. The E4 allele of Apolipoprotein E (APOE) is a well-established genetic risk factor for late onset AD. The ApoE ε4 allele is also associated with retinal neurodegenerative diseases however in contrast to AD, it is considered protective in AMD, likewise ApoE E2 allele, which is a protective factor for AD, has been implicated as a risk factor for AMD and glaucoma. This review summarizes the evidence on the effects of ApoE in retinal neurodegenerative diseases and discusses the overlapping molecular pathways in AD. The involvement of ApoE in regulating amyloid beta (Aβ) and tau pathology, inflammation, vascular integrity, glucose metabolism and vascular endothelial growth factor (VEGF) signaling is also discussed.

Palladium-Catalyzed Synthesis, Acetylcholinesterase Inhibition, and Neuroprotective Activities of N-Aryl Galantamine Analogues

A series of new N-aryl galantamine analogues (5a-5x) were designed and synthesized by modification of galantamine, using Pd-catalyzed Buchwald-Hartwig cross-coupling reaction in good to excellent yields. The cholinesterase inhibitory and neuroprotective activities of N-aryl derivatives of galantamine were evaluated. Among the synthesized compounds, the 4-methoxylpyridine-galantamine derivative (5q) (IC₅₀ = 0.19 μM) exhibited excellent acetylcholinesterase inhibition activity, as well as significant neuroprotective effect against H₂O₂-induced injury in SH-SY5Y cells. Molecular docking, staining, and Western blotting analyses were performed to demonstrate the mechanism of action of 5q. Derivative 5q would be a promising multifunctional lead compound for the treatment of Alzheimer's disease.

A novel Alzheimer's disease prognostic signature: identification and analysis of glutamine metabolism genes in immunogenicity and immunotherapy efficacy

Alzheimer's disease (AD) is characterized as a distinct onset and progression of cognitive and functional decline associated with age, as well as a specific neuropathology. It has been discovered that glutamine (Gln) metabolism plays a crucial role in cancer. However, a full investigation of its role in Alzheimer's disease is still missing. This study intended to find and confirm potential Gln-related genes associated with AD using bioinformatics analysis. The discovery of GlnMgs was made possible by the intersection of the WGCNA test and 26 Gln-metabolism genes (GlnMgs). GlnMgs' putative biological functions and pathways were identified using GSVA. The LASSO method was then used to identify the hub genes as well as the diagnostic efficiency of the four GlnMgs in identifying AD. The association between hub GlnMgs and clinical characteristics was also studied. Finally, the GSE63060 was utilized to confirm the levels of expression of the four GlnMgs. Four GlnMgs were discovered (ATP5H, NDUFAB1, PFN2, and SPHKAP). For biological function analysis, cell fate specification, atrioventricular canal development, and neuron fate specification were emphasized. The diagnostic ability of the four GlnMgs in differentiating AD exhibited a good value. This study discovered four GlnMgs that are linked to AD. They shed light on potential new biomarkers for AD and tracking its progression.

A 12-month randomised pilot trial of the Alzheimer's and music therapy study: a feasibility assessment of music therapy and physical activity in patients with mild-to-moderate Alzheimer's disease

BACKGROUND

The Alzheimer's and Music Therapy (ALMUTH) study is the first randomised controlled trial (RCT) design with 12 months of active non-pharmacological therapy (NPT) implementing music therapy (MT) and physical activity (PA) for participants with Alzheimer's disease (AD). The aim of the present article is to retrospectively examine the inclusion of mild-to-moderate Alzheimer's Disease patients into the main ALMUTH study protocol and to determine if continued inclusion of AD patients is warranted.

METHODS

The randomised pilot trial was conducted as a parallel three-arm RCT, reflecting the experimental design of the ALMUTH study. The trial was conducted in Bergen, Norway, and randomisation (1:1:1) was performed by an external researcher. The study was open label and the experimental design features two active NPTs: MT and PA, and a passive control (no intervention, CON) in Norwegian speaking patients with AD who still live at home and could provide informed consent. Sessions were offered once per week (up to 90 min) up to 40 sessions over 12 months. Baseline and follow-up tests included a full neuropsychological test battery and three magnetic resonance imaging (MRI) measurements (structural, functional, and diffusion weighted imaging). Feasibility outcomes were assessed and were determined as feasible if they met the target criteria.

RESULTS

Eighteen participants with a diagnosis of mild-to-moderate AD were screened, randomised, and tested once at baseline and once after 12-months. Participants were divided into three groups: MT (n = 6), PA (n = 6), and CON (n = 6). Results of the study revealed that the ALMUTH protocol in patients with AD was not feasible. The adherence to the study protocol was poor (50% attended sessions), with attrition and retention rates at 50%. The recruitment was costly and there were difficulties acquiring participants who met the inclusion criteria. Issues with study fidelity and problems raised by staff were taken into consideration for the updated study protocol. No adverse events were reported by the patients or their caregivers.

CONCLUSIONS

The pilot trial was not deemed feasible in patients with mild-to-moderate AD. To mitigate this, the ALMUTH study has expanded the recruitment criteria to include participants with milder forms of memory impairment (pre-AD) in addition to expanding the neuropsychological test battery. The ALMUTH study is currently ongoing through 2023.

TRIAL REGISTRATION

Norsk Forskningsråd (NFR) funded. Regional Committees for Medical and Health Research Ethics (REC-WEST: reference number 2018/206).

CLINICALTRIALS

gov: NCT03444181 (registered retrospectively 23 February 2018, https://clinicaltrials.gov/ct2/show/NCT03444181 ).

The Potential Role of Gustatory Function as an Early Diagnostic Marker for the Risk of Alzheimer’s Disease in Subjective Cognitive Decline

Background: Patients with subjective cognitive decline (SCD) report memory deterioration and are at an increased risk of converting to Alzheimer’s disease (AD) although psychophysical testing does not reveal any cognitive deficit. Objective: Here, gustatory function is investigated as a potential predictor for an increased risk of progressive cognitive decline indicating higher AD risk in SCD. Methods: Measures of smell and taste perception as well as neuropsychological data were assessed in patients with subjective cognitive decline (SCD): Subgroups with an increased likelihood of the progression to preclinical AD (SCD+) and those with a lower likelihood (SCD–) were compared to healthy controls (HC), patients with mild cognitive impairment and AD patients. The Sniffin’ Sticks test contained 12 items with different qualities and taste was measured with 32 taste stripes (sweet, salty, bitter, sour) of different concentration. Results: Only taste was able to distinguish between HC/SCD– and SCD+ patients. Conclusion: This study provides a first hint of taste as a more sensitive marker than smell for detecting preclinical AD in SCD. Longitudinal observation of cognition and pathology are necessary to further evaluate taste perception as a predictor of pathological objective decline in cognition.

FDA's dilemma with the aducanumab approval: public pressure and hope, surrogate markers and efficacy, and possible next steps

Accelerating Food and Drug Administration (FDA) product approval to market based on surrogate markers in the absence of proven efficacy creates a risk of adverse outcomes for affected patients, even in response to a life-threatening condition, such as in this case, Alzheimer's disease. FDA's recent unexpected approval of aducanumab, despite the unified opposition of its own highly respected advisory committee after the early termination of two efficacy trials, creates the potential risk of adverse effects and lack of clinical efficacy at very high costs. In view of these concerns, a thorough review of the issues and pressures that led to this decision is worth the careful consideration of the clinical and scientific communities with regard to whether this approval represents a calculated and balanced compassionate decision versus a disturbing precedent.

Therapeutic potential of melatonin and its derivatives in aging and neurodegenerative diseases

Aging is associated with increasing impairments in brain homeostasis and represents the main risk factor across most neurodegenerative disorders. Melatonin, a neuroendocrine hormone that regulates mammalian chronobiology and endocrine functions is well known for its antioxidant potential, exhibiting both cytoprotective and chronobiotic abilities. Age-related decline of melatonin disrupting mitochondrial homeostasis and cytosolic DNA-mediated inflammatory reactions in neurons is a major contributory factor in the emergence of neurological abnormalities. There is scattered literature on the possible use of melatonin against neurodegenerative mechanisms in the aging process and its associated diseases. We have searched PUBMED with many combinations of key words for available literature spanning two decades. Based on the vast number of experimental papers, we hereby review recent advancements concerning the potential impact of melatonin on cellular redox balance and mitochondrial dynamics in the context of neurodegeneration. Next, we discuss a broader explanation of the involvement of disrupted redox homeostasis in the pathophysiology of age-related diseases and its connection to circadian mechanisms. Our effort may result in the discovery of novel therapeutic approaches. Finally, we summarize the current knowledge on molecular and circadian regulatory mechanisms of melatonin to overcome neurodegenerative diseases (NDDs) such as Alzheimer's, Parkinson's, Huntington's disease, and amyotrophic lateral sclerosis, however, these findings need to be confirmed by larger, well-designed clinical trials. This review is also expected to uncover the associated molecular alterations in the aging brain and explain how melatonin-mediated circadian restoration of neuronal homeodynamics may increase healthy lifespan in age-related NDDs.

Whole-body vibration ameliorates glial pathological changes in the hippocampus of hAPP transgenic mice, but does not affect plaque load

BACKGROUND

Alzheimer's disease (AD) is the core cause of dementia in elderly populations. One of the main hallmarks of AD is extracellular amyloid beta (Aβ) accumulation (APP-pathology) associated with glial-mediated neuroinflammation. Whole-Body Vibration (WBV) is a passive form of exercise, but its effects on AD pathology are still unknown.

METHODS

Five months old male J20 mice (n = 26) and their wild type (WT) littermates (n = 24) were used to investigate the effect of WBV on amyloid pathology and the healthy brain. Both J20 and WT mice underwent WBV on a vibration platform or pseudo vibration treatment. The vibration intervention consisted of 2 WBV sessions of 10 min per day, five days per week for five consecutive weeks. After five weeks of WBV, the balance beam test was used to assess motor performance. Brain tissue was collected to quantify Aβ deposition and immunomarkers of astrocytes and microglia.

RESULTS

J20 mice have a limited number of plaques at this relatively young age. Amyloid plaque load was not affected by WBV. Microglia activation based on IBA1-immunostaining was significantly increased in the J20 animals compared to the WT littermates, whereas CD68 expression was not significantly altered. WBV treatment was effective to ameliorate microglia activation based on morphology in both J20 and WT animals in the Dentate Gyrus, but not so in the other subregions. Furthermore, GFAP expression based on coverage was reduced in J20 pseudo-treated mice compared to the WT littermates and it was significantly reserved in the J20 WBV vs. pseudo-treated animals. Further, only for the WT animals a tendency of improved motor performance was observed in the WBV group compared to the pseudo vibration group.

CONCLUSION

In accordance with the literature, we detected an early plaque load, reduced GFAP expression and increased microglia activity in J20 mice at the age of ~ 6 months. Our findings indicate that WBV has beneficial effects on the early progression of brain pathology. WBV restored, above all, the morphology of GFAP positive astrocytes to the WT level that could be considered the non-pathological and hence "healthy" level. Next experiments need to be performed to determine whether WBV is also affective in J20 mice of older age or other AD mouse models.

Links between COVID-19 and Alzheimer's Disease-What Do We Already Know?

Alzheimer's disease (AD) is a life-changing condition whose etiology is explained by several hypotheses. Recently, a new virus contributed to the evidence of viral involvement in AD: the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes the COVID-19 coronavirus disease. AD was found to be one of the most common COVID-19 comorbidities, and it was found to increase mortality from this disease as well. Moreover, AD patients were observed to present with the distinct clinical features of COVID-19, with delirium being prevalent in this group. The SARS-CoV-2 virus enters host cells through the angiotensin-converting enzyme 2 (ACE2) receptor. ACE2 is overexpressed in brains with AD, which thus increases the viral invasion. Furthermore, the inhibition of the ACE2 receptor by the SARS-CoV-2 virus may also decrease the brain-derived neurotrophic factor (BDNF), contributing to neurodegeneration. The ApoE ε4 allele, which increases the risk of AD, was found to facilitate the SARS-CoV-2 entry into cells. Furthermore, the neuroinflammation and oxidative stress existing in AD patients enhance the inflammatory response associated with COVID-19. Moreover, pandemic and associated social distancing measures negatively affected the mental health, cognitive function, and neuro-psychiatric symptoms of AD patients. This review comprehensively covers the links between COVID-19 and Alzheimer's disease, including clinical presentation, molecular mechanisms, and the effects of social distancing.

Vitamin D, a Secosteroid Hormone and Its Multifunctional Receptor, Vitamin D Receptor, in Alzheimer's Type Neurodegeneration

Vitamin D is a secosteroid hormone exerting neurosteroid-like properties. Its well-known nuclear hormone receptor, and recently proposed as a mitochondrial transcription factor, vitamin D receptor, acts for its primary functions. The second receptor is an endoplasmic reticulum protein, protein disulfide isomerase A3 (PDIA3), suggested to act as a rapid response. Vitamin D has effects on various systems, particularly through calcium metabolism. Among them, the nervous system has an important place in the context of our subject. Recent studies have shown that vitamin D and its receptors have numerous effects on the nervous system. Neurodegeneration is a long-term process. Throughout a human life span, so is vitamin D deficiency. Our previous studies and others have suggested that the out-come of long-term vitamin D deficiency (hypovitaminosis D or inefficient utilization of vitamin D), may lead neurons to be vulnerable to aging and neurodegeneration. We suggest that keeping vitamin D levels at adequate levels at all stages of life, considering new approaches such as agonists that can activate vitamin D receptors, and utilizing other derivatives produced in the synthesis process with UVB are crucial when considering vitamin D-based intervention studies. Given most aspects of vitamin D, this review outlines how vitamin D and its receptors work and are involved in neurodegeneration, emphasizing Alzheimer's disease.

Amyloid-beta aggregation implicates multiple pathways in Alzheimer's disease: Understanding the mechanisms

Alzheimer's disease (AD) is a progressive neurodegenerative condition characterized by tau pathology and accumulations of neurofibrillary tangles (NFTs) along with amyloid-beta (Aβ). It has been associated with neuronal damage, synaptic dysfunction, and cognitive deficits. The current review explained the molecular mechanisms behind the implications of Aβ aggregation in AD via multiple events. Beta (β) and gamma (γ) secretases hydrolyzed amyloid precursor protein (APP) to produce Aβ, which then clumps together to form Aβ fibrils. The fibrils increase oxidative stress, inflammatory cascade, and caspase activation to cause hyperphosphorylation of tau protein into neurofibrillary tangles (NFTs), which ultimately lead to neuronal damage. Acetylcholine (Ach) degradation is accelerated by upstream regulation of the acetylcholinesterase (AChE) enzyme, which leads to a deficiency in neurotransmitters and cognitive impairment. There are presently no efficient or disease-modifying medications for AD. It is necessary to advance AD research to suggest novel compounds for treatment and prevention. Prospectively, it might be reasonable to conduct clinical trials with unclean medicines that have a range of effects, including anti-amyloid and anti-tau, neurotransmitter modulation, anti-neuroinflammatory, neuroprotective, and cognitive enhancement.

Amyloid precursor protein in Alzheimer's disease

Amyloid precursor protein (APP) is a membrane protein expressed in several tissues. The occurrence of APP is predominant in synapses of nerve cells. It acts as a cell surface receptor and plays a vital role as a regulator of synapse formation, iron export and neural plasticity. It is encoded by the APP gene that is regulated by substrate presentation. APP is a precursor protein activated by proteolytic cleavage and thereby generating amyloid beta (Aβ) peptides which eventually form amyloid plaques that accumulate in Alzheimer's disease patients' brains. In this chapter, we highlight basic mechanism, structure, expression patterns and cleavage of amyloid plaques, and its diagnosis and potential treatment for Alzheimer's disease.

Microglia as a cellular target of diclofenac therapy in Alzheimer's disease

Alzheimer's disease (AD) is an untreatable cause of dementia, and new therapeutic approaches are urgently needed. AD pathology is defined by extracellular amyloid plaques and intracellular neurofibrillary tangles. Research of the past decades has suggested that neuroinflammation plays a critical role in the pathophysiology of AD. This has led to the idea that anti-inflammatory treatments might be beneficial. Early studies investigated non-steroidal anti-inflammatory drugs (NSAIDS) such as indomethacin, celecoxib, ibuprofen, and naproxen, which had no benefit. More recently, protective effects of diclofenac and NSAIDs in the fenamate group have been reported. Diclofenac decreased the frequency of AD significantly compared to other NSAIDs in a large retrospective cohort study. Diclofenac and fenamates share similar chemical structures, and evidence from cell and mouse models suggests that they inhibit the release of pro-inflammatory mediators from microglia with leads to the reduction of AD pathology. Here, we review the potential role of diclofenac and NSAIDs in the fenamate group for targeting AD pathology with a focus on its potential effects on microglia.

The Effect of Aerobic Exercise on Cognitive Function in People with Alzheimer's Disease: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

A growing body of research has examined the effect of aerobic exercise on cognitive function in people with Alzheimer's Disease (AD), but the findings of the available studies were conflicting. The aim of this study was to explore the effect of aerobic exercise on cognitive function in AD patients. Searches were performed in PubMed, Web of Science, and EBSCO databases from the inception of indexing until 12 November 2021. Cochrane risk assessment tool was used to evaluate the methodological quality of the included literature. From 1942 search records initially identified, 15 randomized controlled trials (RCTs) were considered eligible for systematic review and meta-analysis. Included studies involved 503 participants in 16 exercise groups (mean age: 69.2-84 years) and 406 participants (mean age: 68.9-84 years) in 15 control groups. There was a significant effect of aerobic exercise on increasing mini-mental state examination (MMSE) score in AD patients [weighted mean difference (WMD), 1.50 (95% CI, 0.55 to 2.45), p = 0.002]. Subgroup analyses showed that interventions conducted 30 min per session [WMD, 2.52 (95% CI, 0.84 to 4.20), p = 0.003], less than 150 min per week [WMD, 2.10 (95% CI, 0.84 to 3.37), p = 0.001], and up to three times per week [WMD, 1.68 (95% CI, 0.46 to 2.89), p = 0.007] increased MMSE score significantly. In addition, a worse basal cognitive status was associated with greater improvement in MMSE score. Our analysis indicated that aerobic exercise, especially conducted 30 min per session, less than 150 min per week, and up to three times per week, contributed to improving cognitive function in AD patients. Additionally, a worse basal cognitive status contributed to more significant improvements in cognitive function.

Altered glucose metabolism in Alzheimer's disease: Role of mitochondrial dysfunction and oxidative stress

Increasing evidence suggests that abnormal cerebral glucose metabolism is largely present in Alzheimer's disease (AD). The brain utilizes glucose as its main energy source and a decline in its metabolism directly reflects on brain function. Weighing on recent evidence, here we systematically assessed the aberrant glucose metabolism associated with amyloid beta and phosphorylated tau accumulation in AD brain. Interlink between insulin signaling and AD highlighted the involvement of the IRS/PI3K/Akt/AMPK signaling, and GLUTs in the disease progression. While shedding light on the mitochondrial dysfunction in the defective glucose metabolism, we further assessed functional consequences of AGEs (advanced glycation end products) accumulation, polyol activation, and other contributing factors including terminal respiration, ROS (reactive oxygen species), mitochondrial permeability, PINK1/parkin defects, lysosome-mitochondrial crosstalk, and autophagy/mitophagy. Combined with the classic plaque and tangle pathologies, glucose hypometabolism with acquired insulin resistance and mitochondrial dysfunction potentiate these factors to exacerbate AD pathology. To this end, we further reviewed AD and DM (diabetes mellitus) crosstalk in disease progression. Taken together, the present work discusses the emerging role of altered glucose metabolism, contributing impact of insulin signaling, and mitochondrial dysfunction in the defective cerebral glucose utilization in AD.

Pharmacological modulation of phosphodiesterase-7 as a novel strategy for neurodegenerative disorders

Neurodegenerative illness develops as a result of genetic defects that cause changes at numerous levels, including genomic products and biological processes. It entails the degradation of cyclic nucleotides, cyclic adenosine monophosphate (cAMP), and cyclic guanosine monophosphate (cGMP). PDE7 modulates intracellular cAMP signalling, which is involved in numerous essential physiological and pathological processes. For the therapy of neurodegenerative illnesses, the normalization of cyclic nucleotide signalling through PDE inhibition remains intriguing. In this article, we shall examine the role of PDEs in neurodegenerative diseases. Alzheimer's disease, Multiple sclerosis, Huntington's disease, Parkinson's disease, Stroke, and Epilepsy are related to alterations in PDE7 expression in the brain. Earlier, animal models of neurological illnesses including Alzheimer's disease, Parkinson's disease, and multiple sclerosis have had significant results to PDE7 inhibitors, i.e., VP3.15; VP1.14. In addition, modulation of CAMP/CREB/GSK/PKA signalling pathways involving PDE7 in neurodegenerative diseases has been addressed. To understand the etiology, treatment options of these disorders mediated by PDE7 and its subtypes can be the focus of future research.

Amelioration of intracerebroventricular streptozotocin-induced cognitive dysfunction by Ocimum sanctum L. through the modulation of inflammation and GLP-1 levels

DPP-4 inhibitors have been shown to reverse amyloid deposition in Alzheimer's disease (AD) patients with cognitive impairment. Ocimum sanctum L. leaves reported the presence of important phytoconstituents which are reported to have DPP-4 inhibitory activity. To investigate the effects of petroleum ether extract of Ocimum sanctum L. (PEOS) in Intracerebroventricular streptozotocin (ICV-STZ) induced AD rats. ICV-STZ (3 mg/kg) was injected bilaterally into male Wistar rats, while sham animals received the artificial CSF. The ICV-STZ-induced rats were administered with three doses of PEOS (100, 200, and 400 mg/kg, p.o.) for thirty days. All experimental rats were subjected to behaviour parameters (radial arm maze task and novel object recognition test), neurochemical parameters such as GLP-1, Aβ42, and TNF-α levels, and histopathological examination (Congo red staining) of the left brain hemisphere. PEOS significantly reversed the spatial learning and memory deficit exhibited by ICV-STZ-induced rats. Furthermore, PEOS also shows promising results in retreating Aβ deposition, TNF α, and increasing GLP-1 levels. The histopathological study also showed a significant dose-dependent reduction in amyloid plaque formation and dense granule in PEOS -treated rats as compared to the ICV-STZ induced rats (Negative control). The results show that extract of Ocimum sanctum L. attenuated ICV-STZ-induced learning and memory deficits in rats and has the potential to be employed in the therapy of AD.

Improving Effect of the Policosanol from Ericerus pela Wax on Learning and Memory Impairment Caused by Scopolamine in Mice

Policosanol (PC) is a mixture of long-chain fatty alcohols that exhibits multiple biological activities, such as reducing blood lipid and cholesterol levels, lowering blood pressure, and extenuating liver inflammation. To assess PC’s impact on cognitive behavior and function, PC was prepared from Ericerus pela wax using a reduction method and analyzed using gas chromatography (GC). A total of 60 mice were randomly divided into six groups of 10 animals each: control (0.5% CMC-Na solution, i.g.), model (0.5% CMC-Na solution, i.g.), donepezil (3 mg/kg, i.g.), PC low- (2 g/kg, i.g.), medium (4 g/kg, i.g.), and high- (6 g/kg, i.g.) dose groups. All the groups were administered daily for 28 consecutive days. There were four parameters—escape latency, crossings of platform, swimming distance, and time spent in the target quadrant—that were recorded to evaluate the cognitive performance of mice in the Morris Water Maze (MWM). After MWM testing, the levels of acetylcholine (ACh), acetylcholinesterase (AChE), superoxide dismutase (SOD), malondialdehyde (MDA), and glutathione (GSH) that were present in brain tissue were determined using assay kits. The GC data showed that PC consisted of four major components: tetracosanol (14.40%), hexacosanol (48.97%), octacosanol (25.40%), and triacontanol (4.80%). In the MWM test, PC significantly decreased the escape latency (p < 0.05) and increased the crossings of the platform (p < 0.05) and swimming distance (p < 0.05) and time in the target quadrant (p < 0.05) in rodents compared to that in the model group. Moreover, PC increased the levels of ACh, SOD, and GSH; inhibited AChE; and reduced MDA in the brain tissue of the tested animals. This is the first report to evaluate the efficacy of PC for cognitive behavior and function in animals. Our findings demonstrate that PC from E. pela wax is likely to exert an enhancing effect on learning and memory by promoting the cholinergic system and attenuating oxidative stress, which will provide a new insight into the efficacy of PC and expand its application in the food, nutraceutical, and beverage industries.

A Review of CRISPR Cas9 for Alzheimer’s Disease: Treatment Strategies and Could target APOE e4, APP, and PSEN-1 Gene using CRISPR cas9 Prevent the Patient from Alzheimer’s Disease?

   A Review of CRISPR Cas9 for Alzheimer’s Disease: Treatment Strategies and Could target APOE e4, APP, and PSEN-1 Gene using CRISPR cas9 Prevent the Patient from Alzheimer’s Disease? BACKGROUND: Alzheimer’s disease is a neurodegenerative disorder characterized by the formation of β-amyloid plaques and neurofibrillary tangles from hyperphosphorylated tau. Several studies suggest that targeting the deletion of the APOE e4, PSEN-1, and APP will reduce tau phosphorylation and Aβ protein accumulation, a crucial hypothesis for the causation of Alzheimer’s disease. APOE e4, PSEN-1, and APP with genome editing Clustered Regular interspersed Short Palindromic Repeats-CRISPR-related (CRISPR/Cas9) are thought to have therapeutic promise for Alzheimer’s disease.AIM: The purpose of this study was to determine whether targeting APOE e4, PSEN-1, and APP using CRISPR/Cas9 is an effective therapeutic and whether it has a long-term effect on Alzheimer’s disease.METHODS: The method used in this study summarized articles by examining the titles and abstracts of specific specified keywords. In this situation, the author picked the title and abstract that matched PubMed, Google Scholar, Science Direct, Cochrane, and the Frontiers in Neuroscience; this was followed by checking to see whether the paper was available in full-text. Eventually, the researcher will study the entire article to decide if it is valuable and relevant to the issue.RESULTS: CRISPR/Cas9 deletion of APOE e4, PSEN-1, and APP in induced pluripotent stem cells (iPSC’s) and g2576 mice as APP mutant models reduce tau phosphorylation and Aβ protein accumulation from neurofibrillary tangles and prevent cell death, vascular damage, and dementia. Furthermore, CRISPR/Cas9 deletion in APOE e4, PSEN-1, and APP improved neuronal cell resilience to oxidative stress and inflammation.CONCLUSION: APOE e4, PSEN-1, and APP deletion by genome editing CRISPR/Cas9 is effective to reduce tau phosphorylation and Aβ protein accumulation from neurofibrillary tangles, cell death, vascular damage, and dementia. However, further research is needed to determine the side effects and safety of its use.

Current Progress on Neuroprotection Induced by Artemisia, Ginseng, Astragalus, and Ginkgo Traditional Chinese Medicines for the Therapy of Alzheimer's Disease

Aging is associated with the occurrence of diverse degenerative changes in various tissues and organs and with an increased incidence of neurological disorders, especially neurodegenerative diseases such as Alzheimer's disease (AD). In recent years, the search for effective components derived from medicinal plants in delaying aging and preventing and treating neurodegenerative diseases has been increasing and the number of related publications shows a rising trend. Here, we present a concise, updated review on the preclinical and clinical research progress in the assessment of the therapeutic potential of different traditional Chinese medicines and derived active ingredients and their effect on the signaling pathways involved in AD neuroprotection. Recognized by their multitargeting ability, these natural compounds hold great potential in developing novel drugs for AD.

New compounds from heterocyclic amines scaffold with multitarget inhibitory activity on Aβ aggregation, AChE, and BACE1 in the Alzheimer disease

The preset neurodegenerations in Alzheimer disease (AD) are due to several mechanisms such as amyloidogenic proteolysis, neuroinflammation, mitochondrial dysfunction, neurofibrillary tangles, cholinergic dysfunction, among others. The aim of this work was to develop multitarget molecules for the treatment of AD. Therefore, a family of 64 molecules was designed based on ligand structure pharmacophores able to inhibit the activity of beta secretase (BACE1) and acetylcholinesterase (AChE) as well as to avoid amyloid beta (Aβ_1–42) oligomerization. The backbone of designed molecules consisted of a trisubstituted aromatic ring, one of the substituents was a heterocyclic amine (piperidine, morpholine, pyrrolidine or N-methyl pyrrolidine) separated from the aromatic system by three carbon atoms. The set of compounds was screened in silico employing molecular docking calculations and chemoinformatic analyses. Based on Gibbs free energy of binding, binding mode and in silico predicted toxicity results, three of the best candidates were selected, synthesized, and evaluated in vitro; F3S4-m, F2S4-m, and F2S4-p. All three compounds prevented Aβ_1–42 aggregation (F3S4-m in 30.5%, F2S4-p in 42.1%, and F2S4-m in 60.9%). Additionally, inhibitory activity against AChE (ki 0.40 μM and 0.19 μM) and BACE1 (IC₅₀ 15.97 μM and 8.38 μM) was also observed for compounds F2S4-m and F3S4-m, respectively. Despite the BACE IC₅₀ results demonstrated that all compounds are very less potent respect to peptidomimetic inhibitor (PI-IV IC₅₀ 3.20 nM), we can still say that F3S4-m is capable to inhibit AChE and BACE1.

Current and Near-Future Treatment of Alzheimer's Disease

Recent findings have improved our understanding of the multifactorial nature of AD. While in early asymptomatic stages of AD, increased amyloid-β synthesis and tau hyperphosphorylation play a key role, while in the latter stages of the disease, numerous dysfunctions of homeostatic mechanisms in neurons, glial cells, and cerebrovascular endothelium determine the rate of progression of clinical symptoms. The main driving forces of advanced neurodegeneration include increased inflammatory reactions in neurons and glial cells, oxidative stress, deficiencies in neurotrophic growth and regenerative capacity of neurons, brain insulin resistance with disturbed metabolism in neurons, or reduction of the activity of the Wnt-β catenin pathway, which should integrate the homeostatic mechanisms of brain tissue. In order to more effectively inhibit the progress of neurodegeneration, combination therapies consisting of drugs that rectify several above-mentioned dysfunctions should be used. It should be noted that many widely-used drugs from various pharmacological groups, "in addition" to the main therapeutic indications, have a beneficial effect on neurodegeneration and may be introduced into clinical practice in combination therapy of AD. There is hope that complex treatment will effectively inhibit the progression of AD and turn it into a slowly progressing chronic disease. Moreover, as the mechanisms of bidirectional communication between the brain and microbiota are better understood, it is expected that these pathways will be harnessed to provide novel methods to enhance health and treat AD.

Alzheimer's Disease-Related Psychosis: An Overview of Clinical Manifestations, Pathogenesis, and Current Treatment

Behavioral and psychotic manifestations, including aggression, delusions, and hallucinations, are frequent comorbidities in patients with debilitating nervous illnesses such as Alzheimer's disease (AD), Amyotrophic Lateral Sclerosis, Multiple Sclerosis, and Parkinson's disease. AD-related psychosis may be linked to a poor disease prognosis, highlighting that early detection and management are mandatory. The manifestations are variable and may be very heterogeneous, imposing a real diagnostic issue. Some assessment tools such as BEHAVE-AD, CERAD-BRSD, and the Psycho-Sensory Hallucinations Scale have been designed to facilitate the diagnosis. The mechanisms behind neurodegeneration-related psychosis are complex and are not fully understood, imposing a burden on researchers to find appropriate management modalities. Familial history and some genetic disturbances may have a determinant role in these delusions and hallucinations in cases with AD. The loss of neuronal cells, atrophy in some regions of the central nervous, and synaptic dysfunction may also contribute to these comorbidities. Furthermore, inflammatory disturbances triggered by pro-inflammatory agents such as interleukins and tumor necrosis factors are stratified among the potential risk factors of the onset of numerous psychotic symptoms in Alzheimer's patients. Little is known about the possible management tools; therefore, it is urgent to conduct well-designed trials to investigate pharmacological and non-pharmacological interventions that can improve the care process of these patients. This review summarizes the current findings regarding the AD-related psychosis symptoms, pathological features, assessment, and management.

Environmental enrichment preserves hippocampal neurons in diabetes and stressed rats

This study evaluated the effect of Environmental Enrichment (EE) on neuron morphology in the CA1, CA3 and dentate hilus (DH) regions of the hippocampus by quantitating the total dendritic arborizations. EE is a potential intervention for stress and diabetes. It is capable of mitigating diabetes and stress-induced cognitive and memory deficit. Diabetes and stress were induced in male Wistar rats (4-5 weeks). Diabetic and stressed rats were exposed to EE on Day 2 post STZ injection and subsequently once daily for 30 days. All animals were sacrificed on Day 30. The hippocampus was dissected and processed for Golgi staining to quantitate dendritic arborizations at the CA1, CA2 and DH regions. Diabetes (D) and Diabetes+stress (D+S) groups had significantly fewer apical and basal dendritic branching points (ADBP, BDBP) at CA1 (p<0.01), CA3 (p<0.001) and DH (p<0.001) relative to control group (NC). Diabetes and stressed rats exposed to EE: [D+EE and D+S+EE groups] exhibited significantly denser ADBP and BDBP at all regions relative to D (p<0.001) and (D+S+EE) (p<0.001) groups respectively. EE significantly preserved neuronal arborizations in hippocampus of diabetic and stressed rats, suggesting a potential entity of diabetes and stress management.

Chronic exposure to ambient traffic-related air pollution (TRAP) alters gut microbial abundance and bile acid metabolism in a transgenic rat model of Alzheimer's disease

Background

Traffic-related air pollution (TRAP) is linked to increased risk for age-related dementia, including Alzheimer's disease (AD). The gut microbiome is posited to influence AD risk, and an increase in microbial-derived secondary bile acids (BAs) is observed in AD patients. We recently reported that chronic exposure to ambient TRAP modified AD risk in a sex-dependent manner in the TgF344 AD (TG) rat.

Objectives

In this study, we used samples from the same cohort to test our hypothesis that TRAP sex-dependently produces gut dysbiosis and increases secondary BAs to a larger extent in the TG rat relative to wildtype (WT) controls.

Methods

Male and female TG and age-matched WT rats were exposed to either filtered air (FA) or TRAP from 28 days up to 15 months of age (n = 5-6). Tissue samples were collected after 9 or 14months of exposure.

Results

At 10 months of age, TRAP tended to decrease the alpha diversity as well as the beneficial taxa Lactobacillus and Ruminococcus flavefaciens uniquely in male TG rats as determined by 16 S rDNA sequencing. A basal decrease in Firmicutes/Bacteroidetes (F/B) ratio was also noted in TG rats at 10 months. At 15 months of age, TRAP altered inflammation-related bacteria in the gut of female rats from both genotypes. BAs were more affected by chronic TRAP exposure in females, with a general trend of increase in host-produced unconjugated primary and microbiota-produced secondary BAs. Most of the mRNAs of the hepatic BA-processing genes were not altered by TRAP, except for a down-regulation of the BA-uptake transporter Ntcp in males.

Conclusion

In conclusion, chronic TRAP exposure produced distinct gut dysbiosis and altered BA homeostasis in a sex and host genotype-specific manner.

Long-term exercise pre-training attenuates Alzheimer's disease-related pathology in a transgenic rat model of Alzheimer's disease

Alzheimer's disease (AD) is the most common form of dementia. Despite enormous efforts around the world, there remains no effective cure for AD. This study was performed to investigate the effects of long-term exercise pretreatment on the typical pathology of AD in a novel transgenic AD rat model. Male 2-month-old animals were divided into the following groups: wild-type (WT) rats, AD rats, and AD rats with treadmill exercise pretreatment (AD-Exe). After exercise pretreatment, the Barnes maze task, passive avoidance task, and cued fear conditioning test were performed to test learning and memory function. The elevated plus maze, open field test, sucrose preference test, and forced swim test were conducted to measure anxious-depressive-like behavior. Immunofluorescence staining, Golgi staining, transmission electron microscopy, Western blot analysis, F-Jade C staining, TUNEL staining, and related assay kits were conducted to measure Aβ plaques, tau hyperphosphorylation, neuronal damage, neuronal degeneration, dendritic spine density, synapses, synaptic vesicles, mitochondrial morphology, mitochondrial dynamic, oxidative stress, and neuroinflammation. Behavioral tests revealed that long-term exercise pretreatment significantly alleviated learning and memory dysfunction and anxious-depressive-like behaviors in AD animals. In addition, exercise pretreatment attenuated amyloid-β deposition and tau hyperphosphorylation and preserved spine density, synapses, and presynaptic vesicles. Exercise also inhibited neuronal damage, neuronal apoptosis, and neuronal degeneration. Additional studies revealed the imbalance of mitochondrial dynamics was significantly inhibited by exercise pretreatment accompanied by a remarkable suppression of oxidative stress and neuroinflammation. Our findings suggest that long-term exercise pretreatment alleviated behavioral deficits and typical pathologies of the AD rat model, supporting long-term exercise pretreatment as a potential approach to delay the progression of AD.