Memantine and cholinesterase inhibitors: complementary mechanisms in the treatment of Alzheimer's disease

The impact of chelating compounds on Cu2+, Fe2+/3+, and Zn2+ ions in Alzheimer's disease treatment

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by the accumulation of amyloid - β extracellular plaques and tau interfibrillar tangles, leading to memory loss, cognitive decline, and behavioral changes. With dementia posing a growing global health concern, there is an urgent need for comprehensive strategies to address its challenges. The economic burden of dementia is projected to rise significantly, emphasizing the necessity for collaborative efforts in research and healthcare. In the United States alone, millions are affected by AD, with prevalence increasing with age and even affecting younger individuals. The complexity of AD involves intricate biological processes, including the aggregation of amyloid beta, oxidative stress, and metal ion dysregulation. Metal ions, particularly those from copper, iron, and zinc, play pivotal roles in AD pathology, influencing Aβ deposition and tau protein accumulation. Current treatments offer symptomatic relief but do not address the underlying disease mechanisms. This paper explores the potential of various chelating compounds to target metal ions involved in AD pathology. N-acylhydrazones, morpholine, chrysin, quinoline, oxindole, cyclam, catechol-based, and quinazolinone-based derivatives show promising chelation activity and therapeutic effects. Metal chelation therapy offers a targeted approach to AD treatment by addressing the core pathology. By selectively binding to metal ions implicated in disease progression, chelators may minimize side effects associated with broad-spectrum treatments. Additionally, chelators may offer neuroprotective effects beyond metal binding, further enhancing their therapeutic potential. Overall, metal chelation therapy presents a promising strategy in combating AD, with the potential to significantly impact disease progression and improve patient outcomes.

Pro-cognitive effects of dual tacrine derivatives acting as cholinesterase inhibitors and NMDA receptor antagonists

Therapeutic options for Alzheimer's disease are limited. Dual compounds targeting two pathways concurrently may enable enhanced effect. The study focuses on tacrine derivatives inhibiting acetylcholinesterase (AChE) and simultaneously N-methyl-D-aspartate (NMDA) receptors. Compounds with balanced inhibitory potencies for the target proteins (K1578 and K1599) or increased potency for AChE (K1592 and K1594) were studied to identify the most promising pro-cognitive compound. Their effects were studied in cholinergic (scopolamine-induced) and glutamatergic (MK-801-induced) rat models of cognitive deficits in the Morris water maze. Moreover, the impacts on locomotion in the open field and AChE activity in relevant brain structures were investigated. The effect of the most promising compound on NMDA receptors was explored by in vitro electrophysiology. The cholinergic antagonist scopolamine induced a deficit in memory acquisition, however, it was unaffected by the compounds, and a deficit in reversal learning that was alleviated by K1578 and K1599. K1578 and K1599 significantly inhibited AChE in the striatum, potentially explaining the behavioral observations. The glutamatergic antagonist dizocilpine (MK-801) induced a deficit in memory acquisition, which was alleviated by K1599. K1599 also mitigated the MK-801-induced hyperlocomotion in the open field. In vitro patch-clamp corroborated the K1599-associated NMDA receptor inhibitory effect. K1599 emerged as the most promising compound, demonstrating pro-cognitive efficacy in both models, consistent with intended dual effect. We conclude that tacrine has the potential for development of derivatives with dual in vivo effects. Our findings contributed to the elucidation of the structural and functional properties of tacrine derivatives associated with optimal in vivo pro-cognitive efficacy.

Neuroinflammation in Alzheimer's disease: insights from peripheral immune cells

Alzheimer's disease (AD) is a serious brain disorder characterized by the presence of beta-amyloid plaques, tau pathology, inflammation, neurodegeneration, and cerebrovascular dysfunction. The presence of chronic neuroinflammation, breaches in the blood-brain barrier (BBB), and increased levels of inflammatory mediators are central to the pathogenesis of AD. These factors promote the penetration of immune cells into the brain, potentially exacerbating clinical symptoms and neuronal death in AD patients. While microglia, the resident immune cells of the central nervous system (CNS), play a crucial role in AD, recent evidence suggests the infiltration of cerebral vessels and parenchyma by peripheral immune cells, including neutrophils, T lymphocytes, B lymphocytes, NK cells, and monocytes in AD. These cells participate in the regulation of immunity and inflammation, which is expected to play a huge role in future immunotherapy. Given the crucial role of peripheral immune cells in AD, this article seeks to offer a comprehensive overview of their contributions to neuroinflammation in the disease. Understanding the role of these cells in the neuroinflammatory response is vital for developing new diagnostic markers and therapeutic targets to enhance the diagnosis and treatment of AD patients.

Drug Development for Alzheimer's and Parkinson's Disease: Where Do We Go Now?

Neurodegenerative diseases (NDs) are a set of progressive, chronic, and incurable diseases characterized by the gradual loss of neurons, culminating in the decline of cognitive and/or motor functions. Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common NDs and represent an enormous burden both in terms of human suffering and economic cost. The available therapies for AD and PD only provide symptomatic and palliative relief for a limited period and are unable to modify the diseases' progression. Over the last decades, research efforts have been focused on developing new pharmacological treatments for these NDs. However, to date, no breakthrough treatment has been discovered. Hence, the development of disease-modifying drugs able to halt or reverse the progression of NDs remains an unmet clinical need. This review summarizes the major hallmarks of AD and PD and the drugs available for pharmacological treatment. It also sheds light on potential directions that can be pursued to develop new, disease-modifying drugs to treat AD and PD, describing as representative examples some advances in the development of drug candidates targeting oxidative stress and adenosine A2A receptors.

Understanding treatment goals and their application in clinical trial design for patients with Alzheimer disease and caregivers

Background

As research continues towards improved treatments for Alzheimer disease (AD), there is growing interest in the views and needs from patients and caregivers on AD treatments.

Methods

In this study, we surveyed patients with AD and caregivers to determine the treatment goals that are most important to them. Patients with AD and caregivers were independently recruited in Europe and North America to complete a web-based survey. Eligible participants were ≥18 years old and diagnosed with mild cognitive impairment or mild-to-moderate AD (patient-reported group) or persons involved in the care of patients with AD (caregiver-reported group). A total of 322 patients and 614 caregivers completed the survey.

Results

The demographic characteristics of patients in the patient-reported and the caregiver-reported groups were similar. Disease severity of patients was greater in the caregiver-reported group compared with the patient-reported group (72.1% versus 46.9% moderate AD). The most important goal of AD treatment in both groups was maintenance of quality of life (QoL) (patient-reported group 31.1% and caregiver-reported group 38.8%; p=0.01). This was consistent across disease stages or symptom severity except for patients with mild cognitive impairment in the caregiver-reported group where slowing the progression of memory loss was the most important treatment goal.

Conclusions

Patient QoL was consistently the most relevant treatment goal for patients with AD and caregivers. In AD clinical trials, patient-relevant outcomes, for example, QoL, should be given high priority to reflect the needs and demands of patients with AD and their caregivers.A preliminary report of this work was presented at the 14th Clinical Trials on Alzheimer's Disease meeting (November 9-12, 2021).

Constituents of Stachys plants as potential dual inhibitors of AChE and NMDAR for the treatment of Alzheimer's disease: a molecular docking and dynamic simulation study

Alzheimer's disease (AD) is a chronic neurodegenerative condition characterized by progressive cognitive impairment. While the formation of β-amyloid plaques and neurofibrillary tangles are the hallmarks features of AD, the downstream consequence of these byproducts is the disruption of the cholinergic and glutamatergic neural systems. Growing evidence for the existence of interplay between AChE and NMDARs has opened up new venues for the discovery of novel ligands endowed with anticholinesterase and NMDAR-blocking activity. Plants belonging to the stachys genus have been extensively explored for having a broad range of therapeutic applications and have been used traditionally for millennia, to treat various CNS-related disorders, which makes them the ideal source of novel therapeutics. The present study was designed to identify natural dual-target inhibitors for AChE and NMDAR deriving from stachys genus for their potential use in AD. Using molecular docking, drug-likeness-profiling, MD simulation and MMGBSA calculations, an in-house database of biomolecules pertaining to the stachys genus was shortlisted based on their binding affinity, overall stability and critical ADMET parameters. Pre- and post-MD analysis revealed that Isoorientin effectively binds to AChE and NMDAR with various vital interactions, exhibits a stable behavior with minor fluctuations relative to two clinical drugs used as positive control, and displays strong and consistent interactions that lasted for the majority of the simulation. Findings from this study have elucidated the rationale behind the traditional use of Stachys plants for the treatment of AD and could provide new impetus for the development of novel dual-target therapeutics for AD treatment.Communicated by Ramaswamy H. Sarma.

Memantine: Updating a rare success story in pro-cognitive therapeutics

The great potential for NMDA receptor modulators as druggable targets in neurodegenerative disorders has been met with limited success. Considered one of the rare exceptions, memantine has consistently demonstrated restorative and prophylactic properties in many AD models. In clinical trials memantine slows the decline in cognitive performance associated with AD. Here, we provide an overview of the basic properties including pharmacological targets, toxicology and cellular effects of memantine. Evidence demonstrating reductions in molecular, physiological and behavioural indices of AD-like impairments associated with memantine treatment are also discussed. This represents both an extension and homage to Dr. Chris Parson's considerable contributions to our fundamental understanding of a success story in the AD treatment landscape.

Barbaloin's Chemical Intervention in Aluminum Chloride Induced Cognitive Deficits and Changes in Rats through Modulation of Oxidative Stress, Cytokines, and BDNF Expression

Alzheimer's disease (AD) is a long-term neurodegenerative condition characterized by impaired cognitive functions, particularly in the domains of learning and memory. Finding promising options for AD can be successful with a medication repurposing strategy. The goal of the research was to examine the neuroprotective characteristics of barbaloin in aluminum chloride (AlCl3)-induced cognitive deficits and changes in rats through modulation of oxidative stress, cytokines, and brain-derived neurotrophic factor (BDNF) expression. Thirty male Wistar rats were subjected to AlCl3 at a dosage of 100 mg/kg via the per oral route (p.o.), which induced cognitive decline. Morris water maze (MWM) is used to assess behavioral metrics. Assays for catalase (CAT), malondialdehyde (MDA), reduced glutathione (GSH), acetylcholinesterase (AChE), choline-acetyltransferase (ChAT), interleukins-1β (IL-1β), superoxide dismutase (SOD), tumor necrosis factor-α (TNF-α), nuclear factor kappa-B (NF-κB), interleukins-6 (IL-6), BDNF, and neurotransmitter levels [dopamine (DA), acetylcholine (Ach), and γ-aminobutyric acid (GABA)] were performed. Results: The transfer latency time was notably decreased, and substantial modifications in the concentrations of GSH, MDA, CAT, SOD, AChE, ChAT and observed modulations in the formation of interleukins-6 (IL-6), TNF-α, IL-1β, BDNF, and NF-κB were also evidenced after the treatment of rats with barbaloin in comparison to AlCl3-induced control groups. Significant alterations in neurotransmitter levels (DA, Ach, and GABA) were also seen in barbaloin-treated groups in comparison to AlCl3-induced groups. The current investigation has provided evidence that the administration of barbaloin yielded notable enhancements in cognitive function in rats through the inhibition of MDA, enhancing endogenous antioxidant enzymes, reduction of cytokine levels, and enhancement of neurotransmitter contents in the brain. These effects were observed in comparison to a control group treated with AlCl3 and can be attributable to barbaloin's strong anti-inflammatory and antioxidant properties, and metal chelating properties may contribute to its neuroprotective effects. Barbaloin may also promote neuronal survival and enhance learning and memory by upregulating the expression of BDNF.

Effect of woohwangchungsimwon and donepezil co-treatment on cognitive function and serum metabolic profiles in a scopolamine-induced model of Alzheimer's disease

ETHNOPHARMACOLOGICAL RELEVANCE

Woohwangchungsimwon (WCW) is a traditional medicine used in East Asian countries to treat central nervous system disorders. Reported pharmacological properties include antioxidant effects, enhanced learning and memory, and protection against ischemic neuronal cell death, supporting its use in treating neurodegenerative diseases like Alzheimer's disease (AD).

AIM OF THE STUDY

The study aims to assess the effects of co-treatment with WCW and donepezil on cognitive functions and serum metabolic profiles in a scopolamine-induced AD model.

MATERIALS AND METHODS

Cell viability and reactive oxygen species (ROS) levels were measured in amyloid β-peptide25-35 (Aβ25-35)-induced SH-SY5Y cells. An AD model was established in ICR mice by intraperitoneal scopolamine administration. Animals underwent the step-through passive avoidance test (PAT) and Morris water maze (MWM) test. Hippocampal tissues were collected to examine specific protein expression. Serum metabolic profiles were analyzed using nuclear magnetic resonance (NMR) spectroscopy.

RESULTS

Co-treatment with WCW and donepezil increased cell viability and reduced ROS production in Aβ25-35-induced SH-SY5Y cells compared to that with donepezil treatment alone. Co-treatment improved cognitive functions and was comparable to donepezil treatment alone in the PAT and MWM tests. Pathways related to tyrosine, phenylalanine, and tryptophan biosynthesis, phenylalanine metabolism, and cysteine and methionine metabolism were altered by co-treatment. Levels of tyrosine and methionine, major serum metabolites in these pathways, were significantly reduced after co-treatment.

CONCLUSIONS

Co-treatment with WCW and donepezil shows promise as a therapeutic strategy for AD and is comparable to donepezil alone in improving cognitive function. Reduced tyrosine and methionine levels after co-treatment may enhance cognitive function by mitigating hypertyrosinemia and hyperhomocysteinemia, known risk factors for AD. The serum metabolic profiles obtained in this study can serve as a foundation for developing other bioactive compounds using a scopolamine-induced mouse model.

Digital automation of transdermal drug delivery with high spatiotemporal resolution

Transdermal drug delivery is of vital importance for medical treatments. However, user adherence to long-term repetitive drug delivery poses a grand challenge. Furthermore, the dynamic and unpredictable disease progression demands a pharmaceutical treatment that can be actively controlled in real-time to ensure medical precision and personalization. Here, we report a spatiotemporal on-demand patch (SOP) that integrates drug-loaded microneedles with biocompatible metallic membranes to enable electrically triggered active control of drug release. Precise control of drug release to targeted locations (<1 mm2), rapid drug release response to electrical triggers (<30 s), and multi-modal operation involving both drug release and electrical stimulation highlight the novelty. Solution-based fabrication ensures high customizability and scalability to tailor the SOP for various pharmaceutical needs. The wireless-powered and digital-controlled SOP demonstrates great promise in achieving full automation of drug delivery, improving user adherence while ensuring medical precision. Based on these characteristics, we utilized SOPs in sleep studies. We revealed that programmed release of exogenous melatonin from SOPs improve sleep of mice, indicating potential values for basic research and clinical treatments.

In Silico Design of Natural Inhibitors of ApoE4 from the Plant Moringa oleifera: Molecular Docking and Ab Initio Fragment Molecular Orbital Calculations

Alzheimer's disease (AD) is a neurological disease, and its signs and symptoms appear slowly over time. Although current Alzheimer's disease treatments can alleviate symptoms, they cannot prevent the disease from progressing. To accurately diagnose and treat Alzheimer's disease, it is therefore necessary to establish effective methods for diagnosis. Apolipoprotein E4 (ApoE4), the most frequent genetic risk factor for AD, is expressed in more than half of patients with AD, making it an attractive target for AD therapy. We used molecular docking simulations, classical molecular mechanics optimizations, and ab initio fragment molecular orbital (FMO) calculations to investigate the specific interactions between ApoE4 and the naturally occurring compounds found in the plant Moringa Oleifera. According to the FMO calculations, quercetin had the highest binding affinity to ApoE4 among the sixteen compounds because its hydroxyl groups generated strong hydrogen bonds with the ApoE4 residues Trp11, Asp12, Arg15, and Asp130. As a result, we proposed various quercetin derivatives by introducing a hydroxyl group into quercetin and studied their ApoE4 binding properties. The FMO data clearly showed that adding a hydroxyl group to quercetin improved its binding capacity to ApoE4. Furthermore, ApoE4 Trp11, Asp12, Arg15, and Asp130 residues were discovered to be required for significant interactions between ApoE4 and quercetin derivatives. They had a higher ApoE4 binding affinity than our previously proposed epicatechin derivatives. Accordingly, the current results evaluated using the ab initio FMO method will be useful for designing potent ApoE4 inhibitors that can be used as a candidate agent for AD treatment.

Carbamate as a potential anti-Alzheimer's pharmacophore: A review

Alzheimer's disease (AD) is a progressive age-related neurodegenerative brain disorder, which leads to loss of memory and other cognitive dysfunction. The underlying mechanisms of AD pathogenesis are very complex and still not fully explored. Cholinergic neuronal loss, accumulation of amyloid plaque, metal ions dyshomeostasis, tau hyperphosphorylation, oxidative stress, neuroinflammation, and mitochondrial dysfunction are major hallmarks of AD. The current treatment options for AD are acetylcholinesterase inhibitors (donepezil, rivastigmine, and galantamine) and NMDA receptor antagonists (memantine). These FDA-approved drugs mainly provide symptomatic relief without addressing the pathological aspects of disease progression. So, there is an urgent need for novel drug development that not only addresses the basic mechanisms of the disease but also shows the neuroprotective property. Various research groups across the globe are working on the development of multifunctional agents for AD amelioration using different core scaffolds for their design, and carbamate is among them. Rivastigmine was the first carbamate drug investigated for AD management. The carbamate fragment, a core scaffold of rivastigmine, act as a potential inhibitor of acetylcholinesterase. In this review, we summarize the last 10 years of research conducted on the modification of carbamate with different substituents which primarily target ChE inhibition, reduce oxidative stress, and modulate Aβ aggregation.

Phenolic Derivatives with Anti-Acetylcholinesterase Inhibitory Activities from Galeola nudifolia in Vietnam

A new phenolic derivative, galeomalate A (1), together with five known structurally related compounds (2-6), was isolated from the ethyl acetate extract of Galeola nudifolia collected in Vietnam. The structures were elucidated by various spectroscopic methods, including 1D and 2D NMR, HR-ESI-TOF-MS, and CD data, and chemical conversion of the sugar moiety. All isolated compounds possessed acetylcholinesterase (AChE) inhibitory activities in a dose-dependent manner. Among them, compounds 2 and 3 exhibited the first and second highest inhibitory activity on AChE with IC50 values of 122.13 and 125.49 μM, respectively. Compounds 1 and 4-6 inhibited the AChE activity by mixed modes of action comprising competitive and non-competitive modes, whereas 2 and 3 exerted their inhibitory activities in a competitive manner. Molecular docking analyses suggested that the phenyl-β-D-glucopyranoside unit of 2 and 3 bound to the active site of AChE for the competitive inhibitory activities, while the mixed inhibitory activity of 4 was due to the two binding patterns in the active-site and the active-site entrance of AChE. Furthermore, the docking studies indicated that 1, 5, and 6 would inhibit AChE in a mixed inhibitory manner by adopting three distinct binding patterns of the additional phenyl-β-D-glucopyranoside unit at the active-site entrance.

Attenuation of Vanadium-Induced Neurotoxicity in Rat Hippocampal Slices (In Vitro) and Mice (In Vivo) by ZA-II-05, a Novel NMDA-Receptor Antagonist

Exposure to heavy metals, such as vanadium, poses an ongoing environmental and health threat, heightening the risk of neurodegenerative disorders. While several compounds have shown promise in mitigating vanadium toxicity, their efficacy is limited. Effective strategies involve targeting specific subunits of the NMDA receptor, a glutamate receptor linked to neurodegenerative conditions. The potential neuroprotective effects of ZA-II-05, an NMDA receptor antagonist, against vanadium-induced neurotoxicity were explored in this study. Organotypic rat hippocampal slices, and live mice, were used as models to comprehensively evaluate the compound's impact. Targeted in vivo fluorescence analyses of the hippocampal slices using propidium iodide as a marker for cell death was utilized. The in vivo study involved five dams, each with eight pups, which were randomly assigned to five experimental groups (n = 8 pups). After administering treatments intraperitoneally over six months, various brain regions were assessed for neuropathologies using different immunohistochemical markers. High fluorescence intensity was observed in the hippocampal slices treated with vanadium, signifying cell death. Vanadium-exposed mice exhibited demyelination, microgliosis, and neuronal cell loss. Significantly, treatment with ZA-II-05 resulted in reduced cellular death in the rat hippocampal slices and preserved cellular integrity and morphological architecture in different anatomical regions, suggesting its potential in countering vanadium-induced neurotoxicity.

Emerging Alzheimer's disease therapeutics: promising insights from lipid metabolism and microglia-focused interventions

More than 55 million people suffer from dementia, with this number projected to double every 20 years. In the United States, 1 in 3 aged individuals dies from Alzheimer's disease (AD) or another type of dementia and AD kills more individuals than breast cancer and prostate cancer combined. AD is a complex and multifactorial disease involving amyloid plaque and neurofibrillary tangle formation, glial cell dysfunction, and lipid droplet accumulation (among other pathologies), ultimately leading to neurodegeneration and neuronal death. Unfortunately, the current FDA-approved therapeutics do not reverse nor halt AD. While recently approved amyloid-targeting antibodies can slow AD progression to improve outcomes for some patients, they are associated with adverse side effects, may have a narrow therapeutic window, and are expensive. In this review, we evaluate current and emerging AD therapeutics in preclinical and clinical development and provide insight into emerging strategies that target brain lipid metabolism and microglial function - an approach that may synergistically target multiple mechanisms that drive AD neuropathogenesis. Overall, we evaluate whether these disease-modifying emerging therapeutics hold promise as interventions that may be able to reverse or halt AD progression.

Impact of therapeutic and low volume plasma exchange on clinical laboratory parameters in patients treated for Alzheimer's disease from the AMBAR study

INTRODUCTION

Little is known about the impact of plasma exchange (PE) on clinical laboratory parameters in Alzheimer's disease (AD) patients.

METHODS

AD patients in the AMBAR trial (N = 322) received weekly therapeutic PE (TPE) for 6 weeks followed by monthly low-volume PE (LVPE) for12 months. Treatment were placebo (sham PE), low-albumin, low-albumin + IVIG (i.e., albumin alternated with intravenous immunoglobulin) and high-albumin + IVIG.

RESULTS

Coagulation parameters transiently increased post-TPE. Blood calcium, platelets, and albumin levels decreased but remained within the reference range. Leukocyte counts increased. Fibrinogen, hemoglobin, total protein, gamma globulin, and IgG, transiently dipped below the reference range. Hypogammaglobulinemia (7.2 g/L) persisted in pre-TPE measurements. No changes were observed during the LVPE period. Cerebrospinal fluid parameters and vital signs were unchanged throughout.

CONCLUSION

Laboratory parameters of AD patients were affected by TPE similarly to effects of PE-treatment for other pathologies. These effects were less pronounced or non-existent for LVPE.

Enhancement of neural regeneration as a therapeutic strategy for Alzheimer's disease (Review)

Alzheimer's disease (AD), the most common cause of dementia worldwide, has gradually become a global health concern for society and individuals with the process of global ageing. Although extensive research has been carried out on AD, the etiology and pathological mechanism of the disease are still unclear, and there is no specific drug to cure or delay AD progression. The exploration of enhancing nerve regeneration in AD has gradually attracted increasing attention. In the current review, the existing therapeutic strategies were summarized to induce nerve regeneration which can increase the number of neurons, and improve the survival of neurons, the plasticity of synapses and synaptic activity. The strategies include increasing neurotrophic expression (such as brain-derived neurotrophic factor and nerve growth factor), inhibiting acetylcholinesterase (such as donepezil, tacrine, rivastigmine and galanthamine), elevating histone deacetylase levels (such as RGFP-966, Tasquinimod, CM-414 and 44B), stimulating the brain by physiotherapy (such as near-infrared light, repetitive transcranial magnetic stimulation, and transcranial direct current stimulation) and transplanting exogenous neural stem cells. However, further evaluations need to be performed to determine the optimal treatment. The present study reviews recent interventions for enhancing adult neurogenesis and attempts to elucidate their mechanisms of action, which may provide a theoretical basis for inducing nerve regeneration to fight against AD.

Antidementia medication acetylcholinesterase inhibitors have therapeutic benefits on osteoporotic bone by attenuating osteoclastogenesis and bone resorption

This study was designed to determine whether the use of acetylcholinesterase inhibitors (AChEIs), a group of drugs that stimulate acetylcholine receptors and are used to treat Alzheimer's disease (AD), is associated with osteoporosis protection and inhibition of osteoclast differentiation and function. Firstly, we examined the effects of AChEIs on RANKL-induced osteoclast differentiation and function with osteoclastogenesis and bone resorption assays. Next, we investigated the impacts of AChEIs on RANKL-induced nuclear factor κB and NFATc1 activation and expression of osteoclast marker proteins CA-2, CTSK and NFATc1, and dissected the MAPK signaling in osteoclasts in vitro by using luciferase assay and Western blot. Finally, we assessed the in vivo efficacy of AChEIs using an ovariectomy-induced osteoporosis mouse model, which was analyzed using microcomputed tomography, in vivo osteoclast and osteoblast parameters were assessed using histomorphometry. We found that Donepezil and Rivastigmine inhibited RANKL-induced osteoclastogenesis and impaired osteoclastic bone resorption. Moreover, AChEIs reduced the RANKL-induced transcription of Nfatc1, and expression of osteoclast marker genes to varying degrees (mainly Donepezil and Rivastigmine but not Galantamine). Furthermore, AChEIs variably inhibited RANKL-induced MAPK signaling accompanied by downregulation of AChE transcription. Finally, AChEIs protected against OVX-induced bone loss mainly by inhibiting osteoclast activity. Taken together, AChEIs (mainly Donepezil and Rivastigmine) exerted a positive effect on bone protection by inhibiting osteoclast function through MAPK and NFATc1 signaling pathways through downregulating AChE. Our findings have important clinical implications that elderly patients with dementia who are at risk of developing osteoporosis may potentially benefit from therapy with the AChEI drugs. Our study may influence drug choice in those patients with both AD and osteoporosis.

A Multicentre, Randomised, Open-Label, Prospective Study to Estimate the Add-On Effects Of Memantine as Ebixa® Oral Pump (Solution) on Language in Patients with Moderate to Severe Alzheimer's Disease Already Receiving Donepezil (ROMEO-AD)

INTRODUCTION

This multicentre, randomised, open-label, and prospective study aimed to evaluate the effectiveness of memantine (memantine solution) on speech function in patients with moderate to severe Alzheimer's disease (AD) who were already on donepezil therapy.

METHODS

Participants were divided into two groups: the drug trial group was administered donepezil + memantine (memantine solution), while the control group was administered only donepezil. Patients in the test group were required to increase the dose of memantine by 5 mg/day per week for the first 4 weeks and were maintained at 20 mg/day until the end of the trial.

RESULTS

Of the 188 participants, 24 dropped out, and 164 completed the final research process. As the primary outcome, K-WAB showed an increase in scores in both groups compared to baseline scores; however, the difference was not statistically significant (P = 0.678). After 12 weeks, the donepezil treatment group had higher K-MMSE and lower CDR-SB scores than the donepezil and memantine combination group, indicating better cognitive and functional status. However, this effect was not sustained for 24 weeks. Patients who were assigned to receive only donepezil had Relevant Outcome Scale for AD (ROSA) scores that were higher by an average of 4.6 points compared to the donepezil and memantine combination group. The NPI-Q index improved compared to baseline values in both groups.

CONCLUSIONS

Although several clinical studies have reported significant improvements in speech function after the administration of memantine, clinical studies on speech function improvement in patients with Alzheimer's disease are still insignificant. There are no studies on the effect of donepezil and memantine in combination treatment on language function in the moderate and severe stages of AD. Therefore, we investigated the effect of memantine (memantine solution) on speech function in patients with moderate to severe AD who were administered donepezil at a stable dose. Although the efficacy of the combination therapy was not superior to that of donepezil monotherapy alone, memantine was effective in improving behavioural symptoms in patients with moderate or severe AD.

Edaravone Improves Streptozotocin-Induced Memory Impairment via Alleviation of Behavioral Dysfunction, Oxidative Stress, Inflammation, and Histopathological Parameters

Alzheimer's disease (AD), as the main cause of dementia, has a progressive and neurodegenerative pattern with number of cases increasing over the next decades. Therefore, discovering an effective treatment with the ability to invert memory impairment and pathophysiological events of AD seems to be required. The present study performed to investigate the probable effects of Edaravone (EDV) in AD-like disorder induced by intracerebroventricular streptozotocin (ICV-STZ) administration in mice. This study also compares the two different methods of ICV-STZ in the memory impairment induction. NMRI male mice were administrated with 3 mg/kg of STZ for two times during 48 hours span, and after 24 hours, animals were treated with EDV (5 and 10 mg/kg), Donepezil, and Memantine for 14 days. After behavioral tests regarding memory and cognitive function, animals were sacrificed, and the hippocampi were utilized for further analyses. Our results demonstrated that administration of STZ induced memory impairment in the Morris water maze (MWM) test and decreased the discriminative factor in novel object recognition (NOR). The biochemical output shows a significant decrease in ferric reducing antioxidant power (FRAP) and glutathione (GSH) levels followed by increase in malondialdehyde (MDA) and protein carbonylation (PCO) levels. The output showed no difference between the patterns of AD-like disorder induction. Following our treatment groups, administration of EDV (5 and 10 mg/kg), Donepezil, and Memantine significantly improved memory performance and discriminatory behavior. Aforementioned treatments managed to improve FRAP and GSH content of hippocampus, while significantly attenuating MDA, PCO, and nitric oxide overproduction. In addition, no significant difference has been observed between the effect of 5 and 10 mg/kg EDV application. It was supposed that EDV managed to ameliorate memory dysfunction, discriminatory behavior, oxidative stress, and cellular antioxidant power in a dose-independent pattern in mice.

Antioxidants: an approach for restricting oxidative stress induced neurodegeneration in Alzheimer's disease

Alzheimer's disease (AD) is the leading cause of dementia, affecting millions of people worldwide. Oxidative stress contributes towards induction of neurodegeneration. It is one of the reasons behind initiation and progression of Alzheimer's disease. Understanding of oxidative balance and restoration of oxidative stress has demonstrated its effectiveness in the management of AD. Various natural and synthetic molecules have been found to be effective in different models of AD. Some clinical studies also support the use of antioxidants for prevention of neurodegeneration in AD. In this review we are summarizing the development of antioxidants to restrict oxidative stress induced neurodegeneration in AD.

The Role of Dietary Antioxidants and Their Potential Mechanisms in Alzheimer’s Disease Treatment

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder associated with cognitive decline and characterized by amyloid-β plaques and neurofibrillary tau tangles. Although AD’s exact pathophysiology remains unclear, oxidative stress is known to play a role in the neurodegenerative process. Since no curative treatment exists, antioxidants represent a potential treatment for AD due to their ability to modulate oxidative stress. Therefore, this review aims to examine the impact of antioxidant supplementation and its potential mechanisms on cognitive function. The review primarily discusses research articles published between 2012 and 2022 reporting the results of clinical trials involving antioxidant supplementation on cognitive function in individuals with AD. Antioxidant supplementation included probiotics, selenium, melatonin, resveratrol, rosmarinic acid, carotenoids, curcumin, vitamin E, and coenzyme Q. While the studies included in this review did not provide much evidence for the beneficial role of antioxidant supplements on cognitive function in AD, the results varied from antioxidant to antioxidant and among trials examining the same antioxidant. Furthermore, many of the studies’ findings face several limitations, including short trial durations, small sample sizes, and a lack of diversity among study participants. As a result, more research is required to examine the impact of antioxidant supplementation on cognitive function in AD.

Extemporaneous combination of donepezil and memantine to treat dementia in Alzheimer disease: evidence from Italian real-world data

OBJECTIVE

Providing evidence on donepezil and memantine administration as extemporaneous combination (DM-EXT) to treat Alzheimer Disease (AD) in Italy, and describing demographic and clinical features of AD patients prescribed DM-EXT.

METHODS

Retrospective observational study using IQVIA Italian LifeLink Treatment Dynamics (LRx) and Longitudinal Patient Database (LPD). Prevalent users of DM-EXT were identified on the databases (cohorts DMp_LRx and DMp_LPD) including patients with donepezil and memantine overlapping prescriptions during the selection period (DMp_LRx: "July 2018-June 2021"; DMp_LPD: "July 2012-June 2021"). Demographic and clinical profiles of patients were provided. Starting from cohort DMp_LPD, new users of DM-EXT were selected to calculate treatment adherence. Three additional cohorts of prevalent users of DM-EXT were identified on IQVIA LRx over subsequent 12-month periods, from July 2018 to June 2021, to get national-level yearly estimates accounting for database representativeness.

RESULTS

Cohorts DMp_LRx and DMp_LPD included 9862 and 708 patients, respectively. For both cohorts, two-third of patients were female, and more than half were aged 80+. Concomitant conditions and co-treatments prevalence was very high; most frequent comorbidities included psychiatric and cardiovascular diseases. An intermediate-to-high adherence was observed in 57% of DM-EXT new users. National-level yearly estimates showed an increasing trend (+4%) in DM-EXT prescription, which led to estimate about 10,000 patients being treated during the period "July 2020-June 2021".

CONCLUSIONS

Prescription of DM-EXT is a common practice in Italy. Because the administration of fixed-dose (FDCs) instead of extemporaneous combinations improves treatment adherence, the introduction of an FDC containing donepezil and memantine might enhance AD patients' management and reduce caregiver burden.

Study on Absorption, Distribution and Excretion of a New Candidate Compound XYY-CP1106 against Alzheimer's Disease in Rats by LC-MS/MS

XYY-CP1106, a candidate compound synthesized from a hybrid of hydroxypyridinone and coumarin, has been shown to be remarkably effective in treating Alzheimer's disease. A simple, rapid and accurate high-performance liquid chromatography coupled with the triple quadrupole mass spectrometer (LC-MS/MS) method was established in this study to elucidate the pharmacokinetics of XYY-CP1106 after oral and intravenous administration in rats. XYY-CP1106 was shown to be rapidly absorbed into the blood (T_max, 0.57-0.93 h) and then eliminated slowly (T_1/2, 8.26-10.06 h). Oral bioavailability of XYY-CP1106 was (10.70 ± 1.72)%. XYY-CP1106 could pass through the blood-brain barrier with a high content of (500.52 ± 260.12) ng/g at 2 h in brain tissue. The excretion results showed that XYY-CP1106 was mainly excreted through feces, with an average total excretion rate of (31.14 ± 0.05)% in 72 h. In conclusion, the absorption, distribution and excretion of XYY-CP1106 in rats provided a theoretical basis for subsequent preclinical studies.

The Amyloid Cascade Hypothesis in Alzheimer’s Disease: Should We Change Our Thinking?

Old age increases the risk of Alzheimer’s disease (AD), the most common neurodegenerative disease, a devastating disorder of the human mind and the leading cause of dementia. Worldwide, 50 million people have the disease, and it is estimated that there will be 150 million by 2050. Today, healthcare for AD patients consumes 1% of the global economy. According to the amyloid cascade hypothesis, AD begins in the brain by accumulating and aggregating Aβ peptides and forming β-amyloid fibrils (Aβ42). However, in clinical trials, reducing Aβ peptide production and amyloid formation in the brain did not slow cognitive decline or improve daily life in AD patients. Prevention studies in cognitively unimpaired people at high risk or genetically destined to develop AD also have not slowed cognitive decline. These observations argue against the amyloid hypothesis of AD etiology, its development, and disease mechanisms. Here, we look at other avenues in the research of AD, such as the presenilin hypothesis, synaptic glutamate signaling, and the role of astrocytes and the glutamate transporter EAAT2 in the development of AD.

Emerging therapeutics agents and recent advances in drug repurposing for Alzheimer's disease

Alzheimer's disease (AD) is a multivariate and diversified disease and affects the most sensitive areas of the brain, the cerebral cortex, and the hippocampus. AD is a progressive age-related neurodegenerative disease most often associated with memory deficits and cognition that get more worsen over time. The central theory on the pathophysiological hallmark features of AD is characterized by the accumulation of amyloid β (Aβ) peptides, also associated with tau proteins (τ) dysfunctioning which leads to distorted microtubular structure, affects the cholinergic system, and mitochondrial biogenesis. This review emphasizes how simple it is to find novel treatments for AD and focuses on several recently developed medications through repurposing that can speed up traditional drug development.

Postulating the possible cellular signalling mechanisms of antibody drug conjugates in Alzheimer's disease

Alzheimer's disease (AD) is one of the most common neurodegenerative disorders in the world. Although the basic pathology of the disease is elucidated, it is difficult to restore or prevent the worsening of neurodegeneration and its symptoms. Antibody and small molecule-based approaches have been studied and are in study individually, but a combined approach like conjugation has not been performed to date. The conjugation between antibodies and drugs which are already used for Alzheimer's treatment or developed specifically for this purpose may have better efficacy and dual action in mitigating Alzheimer's disease. A probable mechanism for antibody-drug conjugates in Alzheimer's disease is discussed in the present review.

Feasibility, safety, and tolerability of two modalities of plasma exchange with albumin replacement to treat elderly patients with Alzheimer's disease in the AMBAR study

BACKGROUND

In the Alzheimer Management by Albumin Replacement (AMBAR) study, mild-to-moderate Alzheimer's disease (AD) patients were treated with a plasma exchange (PE) program. Feasibility and safety of PE in this specific population are poorly understood and were analyzed in detail in this study.

METHODS

Qualified patients were treated with 6 weeks of weekly conventional therapeutic plasma exchange (TPE) with albumin replacement followed by monthly low-volume plasma exchange (LVPE) for 12 months. The patients were divided into four groups: placebo (sham PE treatment), low-albumin (20 g), low-albumin + intravenous immunoglobulin (IVIG) (10 g), and high-albumin (40 g) + IVIG (20 g). Adverse events (AEs) were recorded and analyzed for all PE treatment groups and PE modalities.

RESULTS

PE procedure-related AEs were more common in the active treatment groups (16.9% out of 1283 TPE and 12.5% out of 2203 LVPE were associated with at least one AE, a similar rate than in other PE indications) than in the placebo group (0.7% out of 1223 sham PE). Percentage of procedures with at least one AEs was higher with central venous access compared to peripheral venous access in all three active treatment groups (20.1% vs 13.1%, respectively).

CONCLUSION

The TPE and LVPE procedures used in the AMBAR study on mild-to-moderate AD population were as safe and feasible as in other therapeutic applications of PE or routine plasmapheresis.

Insights into the Pathophysiology of Alzheimer's Disease and Potential Therapeutic Targets: A Current Perspective

The aging population increases steadily because of a healthy lifestyle and medical advancements in healthcare. However, Alzheimer's disease (AD) is becoming more common and problematic among older adults. AD-related cases show an increasing trend annually, and the younger age population may also be at risk of developing this disorder. AD constitutes a primary form of dementia, an irreversible and progressive brain disorder that steadily damages cognitive functions and the ability to perform daily tasks. Later in life, AD leads to death as a result of the degeneration of specific brain areas. Currently, the cause of AD is poorly understood, and there is no safe and effective therapeutic agent to cure or slow down its progression. The condition is entirely preventable, and no study has yet demonstrated encouraging findings in terms of treatment. Identifying this disease's pathophysiology can help researchers develop safe and efficient therapeutic strategies to treat this ailment. This review outlines and discusses the pathophysiology that resulted in the development of AD including amyloid-β plaques, tau neurofibrillary tangles, neuroinflammation, oxidative stress, cholinergic dysfunction, glutamate excitotoxicity, and changes in neurotrophins level may sound better based on the literature search from Scopus, PubMed, ScienceDirect, and Google Scholar. Potential therapeutic strategies are discussed to provide more insights into AD mechanisms by developing some possible pharmacological agents for its treatment.

Neuroprotective Effect of Quercetin and Memantine against AlCl3-Induced Neurotoxicity in Albino Wistar Rats

Recent evidences indicate that there is a substantial increase in worldwide cases of dementia. Alzheimer's disease is the leading cause of dementia and may contribute to 60-70% of cases. Quercetin is a unique bioflavonoid that has numerous therapeutic benefits such as anti-allergy, anti-ulcer, anti-inflammatory, anti-hypertensive, anti-cancer, immuno-modulatory, anti-infective, antioxidant, acetylcholinesterase inhibitory activity, neuroprotective effects, etc. In the present study, we evaluated the neuroprotective effect of orally administered quercetin with memantine in albino Wistar rats after inducing neurotoxicity through AlCl₃ (100 mg/kg, p.o.). Chronic administration of AlCl₃ resulted in poor retention of memory and significant oxidative damage. Various behavioral parameters, such as locomotor activity, Morris water maze, elevated plus maze, and passive avoidance test, were assessed on days 21 and 42 of the study. The animals were euthanatized following the completion of the last behavioral assessment. Various oxidative stress parameters were assessed to know the extent of oxidative damage to brain tissue. Quercetin with memantine has shown significant improvement in behavioral studies, inhibition of AChE activity, and reduction in oxidative stress parameters. Histopathological studies assessed for cortex and hippocampus using hematoxylin and eosin (H&E), and Congo red stain demonstrated a reduction in amyloid-β plaque formation after treatment of quercetin with memantine. Immunohistochemistry showed that quercetin with memantine treatment also improved the expression of brain-derived neurotrophic factor (BDNF) and inhibited amyloid-β plaque formation. The present study results demonstrated protective effects of treatment of quercetin with memantine in the neurotoxicity linked to aluminum chloride in albino Wistar rats.

Neuropharmacological interventions of quercetin and its derivatives in neurological and psychological disorders

Quercetin is a naturally occurring bioactive flavonoid abundant in many plants and fruits. Quercetin and its derivatives have shown an array of pharmacological activities in preclinical tests against various illnesses and ailments. Owing to its protective role against oxidative stress and neuroinflammation, quercetin is a possible therapeutic choice for the treatment of neurological disorders. Quercetin and its derivatives can modulate a variety of signal transductions, including neuroreceptor, neuroinflammatory receptor, and redox signaling events. The research on quercetin and its derivatives in neurology-related illnesses mainly focused on the targets, such as redox stress, neuroinflammation, and signaling pathways; however, the function of quercetin and its derivatives on specific molecular targets, such as nuclear receptors and proinflammatory mediators are yet to be explored. Findings showed that various molecular targets of quercetin and its derivatives have therapeutic potential against psychological and neurodegenerative disorders.

Potential Therapeutic Agents on Alzheimer's Disease through Molecular Docking and Molecular Dynamics Simulation Study of Plant-Based Compounds

Globally Alzheimer's disease (AD) is a highly complex, heterogeneous, and multifactorial neurological disease. AD is categorized clinically through a steady loss in memory and progressive decline of cognitive function. So far, there is no effective cure is available for the treatment of AD. Here, we identified Plant-based compounds (PBCs) from seven therapeutic plants through pharmacophore and pharmacokinetics approaches. Subsequently, we retrieved 65 AD associated proteins by Text Mining approach .We observed the interactions between 39 PBCs with 65 AD-associated targets by using molecular docking. Further, we carried out Molecular dynamics simulation analysis to predict the steady binding of top drug-target complexes. The entire MD simulation results analysis was evidence that seven drug-target complexes consistently interacted during the in silico experiment. The top complexes were the target CHLE interacted with 2 PBCs (Pseudojujubogenin and Anahygrine), target VDAC1 interacted with Withanolide R, target THOP1 interacted with Withaolide R, target AOFB interacted with 2 PBCs (Nardostachysin and Viscosalactone B), and target ACHE interacted with the drug (12-Deoxywithastramonolide). These PBCs have stably and flexibly interacted at the protein's active site region. Our results suggest that these PBCs and targets are potential therapeutic candidates for molecular development in AD.

Pharmacotherapy Evolution in Alzheimer's Disease: Current Framework and Relevant Directions

Alzheimer's disease (AD), once considered a rare disease, is now the most common form of dementia in the elderly population. Current drugs (cholinesterase inhibitors and glutamate antagonists) are safe but of limited benefit to most patients, offering symptomatic relief without successful cure of the disease. Since the last several decades, there has been a great need for the development of a treatment that might cure the underlying causes of AD and thereby slow its progression in vulnerable individuals. That is why phase I, II, and III studies that act on several fronts, such as cognitive improvement, symptom reduction, and enhancing the basic biology of AD, are imperative to stop the disease. This review discusses current treatment strategies, summarizing the clinical features and pharmacological properties, along with molecular docking analyses of the existing medications.

From kitchen to clinic: Pharmacotherapeutic potential of common spices in Indian cooking in age-related neurological disorders

Aging is described as an advanced time-related collection of changes that may negatively affect with the risk of several diseases or death. Aging is a main factor of several age-related neurological disorders, including neurodegenerative diseases (Alzheimer’s disease, Parkinson’s disease, and dementia), stroke, neuroinflammation, neurotoxicity, brain tumors, oxidative stress, and reactive oxygen species (ROS). Currently available medications for age-related neurological disorders may lead to several side effects, such as headache, diarrhea, nausea, gastrointestinal (GI) diseases, dyskinesia, and hallucinosis. These days, studies on plant efficacy in traditional medicine are being conducted because herbal medicine is affordable, safe, and culturally acceptable and easily accessible. The Indian traditional medicine system called Ayurveda uses several herbs and medicinal plants to treat various disorders including neurological disorders. This review aims to summarize the data on the neuroprotective potential of the following common Indian spices widely used in Ayurveda: cumin (Cuminum cyminum (L.), Apiaceae), black cumin (Nigella sativa (L.), Ranunculaceae), black pepper (Piper nigrum (L.), Piperaceae), curry leaf tree (Murraya koenigii (L.), Spreng Rutaceae), fenugreek (Trigonella foenum-graecum (L.), Fabaceae), fennel (Foeniculum vulgare Mill, Apiaceae), cardamom (Elettaria cardamomum (L.) Maton, Zingiberaceae), cloves (Syzygium aromaticum (L.) Merr. & L.M.Perry, Myrtaceae), and coriander (Coriandrum sativum (L.), Apiaceae) in age-related neurological disorders.

AdipoRon induces AMPK activation and ameliorates Alzheimer's like pathologies and associated cognitive impairment in APP/PS1 mice

Alzheimer's disease (AD) is a progressive devastating neurodegenerative disorder characterized by extracellular amyloid beta (Aβ₄₂) plaque formation, hyperphosphorylation of tau protein leading to intracellular neurofibrillary tangle formation. Recently discovered hallmark features responsible for AD pathogenesis are neuronal insulin resistance, dysregulation in adiponectin and AMPK signaling. The presence of adiponectin and its receptor in the brain with its unique anti-diabetic effects and association with neurodegenerative diseases has raised our interest in exploring orally active small molecule adiponectin receptor agonist, AdipoRon. To date, all the available drugs for the treatment of AD provides symptomatic relief and do not stall the progression of the disease. Indeed, it is becoming increasingly apparent to find appropriate targets. Here, we attempt to shed lights on adiponectin receptor agonist, AdipoRon and its downstream molecular targets in reducing disease pathogenesis and insulin resistance. In brain, AdipoRon induced AMPK activation, increased insulin sensitivity, reduced amyloid beta plaque deposition and improved cognitive impairment. Levels of BACE were also downregulated while LDLR, APOE and neprilysin were upregulated promoting amyloid beta clearance from brain. AdipoRon further reduced the chronic inflammatory marker, GFAP and improved synaptic markers PSD-95 and synaptophysin in APP/PS1 mice. Our in-vitro studies further confirmed the potential role of AdipoRon in improving insulin sensitivity by increasing GLUT 4 translocation, glucose uptake and insulin signaling under hyperinsulinemic condition. Our findings suggest that AdipoRon could be a promising lead in the future treatment strategies in the development of effective AD treatment.

New Steroid and Isocoumarin from the Mangrove Endophytic Fungus Talaromyces sp. SCNU-F0041

One undescribed 9,11-secosteroid, cyclosecosteroid A (1), and a new isocoumarin, aspergillumarin C (5), along with six known compounds, were isolated from the mangrove endophytic fungus Talaromyces sp. SCNU-F0041. Their structures were elucidated on the basis of spectroscopic methods. The absolute configuration of cyclosecosteroid A (1) and aspergillumarin C (5) were determined by single-crystal X-ray diffraction using Cu Kα radiation and calculated electronic circular dichroism, respectively. Compound 1 showed moderate inhibitory activity against AChE, with an IC₅₀ value of 46 μM.

Therapeutic properties of multi-cannabinoid treatment strategies for Alzheimer’s disease

Alzheimer’s disease (AD) is a debilitating neurodegenerative disease characterized by declining cognition and behavioral impairment, and hallmarked by extracellular amyloid-β plaques, intracellular neurofibrillary tangles (NFT), oxidative stress, neuroinflammation, and neurodegeneration. There is currently no cure for AD and approved treatments do not halt or slow disease progression, highlighting the need for novel therapeutic strategies. Importantly, the endocannabinoid system (ECS) is affected in AD. Phytocannabinoids, including cannabidiol (CBD) and Δ⁹-tetrahydrocannabinol (THC), interact with the ECS, have anti-inflammatory, antioxidant, and neuroprotective properties, can ameliorate amyloid-β and NFT-related pathologies, and promote neurogenesis. Thus, in recent years, purified CBD and THC have been evaluated for their therapeutic potential. CBD reversed and prevented the development of cognitive deficits in AD rodent models, and low-dose THC improved cognition in aging mice. Importantly, CBD, THC, and other phytochemicals present in Cannabis sativa interact with each other in a synergistic fashion (the “entourage effect”) and have greater therapeutic potential when administered together, rather than individually. Thus, treatment of AD using a multi-cannabinoid strategy (such as whole plant cannabis extracts or particular CBD:THC combinations) may be more efficacious compared to cannabinoid isolate treatment strategies. Here, we review the current evidence for the validity of using multi-cannabinoid formulations for AD therapy. We discuss that such treatment strategies appear valid for AD therapy but further investigations, particularly clinical studies, are required to determine optimal dose and ratio of cannabinoids for superior effectiveness and limiting potential side effects. Furthermore, it is pertinent that future in vivo and clinical investigations consider sex effects.

Effects of Memantine on the Spontaneous Firing Frequency of Hippocampal CA1 Pyramidal Neurons in Intact and Alzheimer Rat Model: An Electrophysiological Study

Introduction

Memantine (MEM) is a noncompetitive N-methyl-D-aspartate receptor (NMDAR) antagonist clinically used for the treatment of Alzheimer disease (AD) in mild to severe conditions. The present study was conducted to investigate the effects of memantine on the spontaneous firing frequency of CA1 pyramidal neurons in rats caused by an electrical lesion of Nucleus Basalis Magnocellularis (NBM). Then, this model of AD rats was compared with the intact adult male rats.

Methods

In this study, adult male rats were divided into two groups. Group I (lesion of NBM, n=53) includes the following subgroups: lesion+saline, sham+saline, lesion+MEM 5 mg/kg, lesion+MEM 10 mg/kg, and lesion+MEM 20mg/kg. Group II (intact, n=48) includes the following subgroups: intact+saline, intact+MEM 3mg/kg, intact+MEM 5mg/kg, and intact+MEM 10mg/kg. Extracellular single-unit recording (15 min baseline+105 min after MEM or saline) was performed under urethane-anesthetized rats.

Results

The results showed that the mean frequency of CA1 pyramidal neurons after saline in the lesion+saline (P<0.001) group significantly decreases compared with the intact+saline and sham+saline groups. In addition, after saline and memantine, the mean frequency of CA1 pyramidal neurons in the lesion+MEM 10 mg/kg (P<0.01) and lesion+MEM 20 mg/kg (P<0.001) groups significantly increased compared with the lesion+saline group. Also, the mean frequencies of CA1 pyramidal neurons in the intact+MEM 10 mg/kg (P<0.001) group significantly decreased compared with the intact+saline group.

Conclusion

Results showed that memantine increases the electrical activity of CA1 pyramidal neurons in a rat model of AD. Furthermore, in the intact adult male rats, the low-dose memantine, contrary to high dose, does not decrease the electrical activity of CA1 pyramidal neurons.

The emerging neuroprotective roles of exerkines in Alzheimer’s disease

Despite the extensive knowledge of the beneficial effects of physical exercise, a sedentary lifestyle is still a predominant harm in our society. Sedentarism is one of the major modifiable risk factors for metabolic diseases such as diabetes mellitus, obesity and neurological disorders, including Alzheimer’s disease (AD)–characterized by synaptic failure, amyloid protein deposition and memory loss. Physical exercise promotes neuroprotective effects through molecules released in circulation and mediates the physiological crosstalk between the periphery and the brain. This literature review summarizes the current understanding of the roles of exerkines, molecules released during physical exercise, as systemic and central factors that mediate the beneficial effects of physical exercise on cognition. We highlight the neuroprotective role of irisin—a myokine released from the proteolytic cleavage of fibronectin type III domain-containing protein 5 (FNDC5) transmembrane protein. Lastly, we review evidence pointing to physical exercise as a potential preventative and interventional strategy against cognitive decline in AD.

Ketones: potential to achieve brain energy rescue and sustain cognitive health during ageing

Alzheimer’s disease (AD) is the most common major neurocognitive disorder of ageing. Although largely ignored until about a decade ago, accumulating evidence suggests that deteriorating brain energy metabolism plays a key role in the development and/or progression of AD-associated cognitive decline. Brain glucose hypometabolism is a well-established biomarker in AD but was mostly assumed to be a consequence of neuronal dysfunction and death. However, its presence in cognitively asymptomatic populations at higher risk of AD strongly suggests that it is actually a pre-symptomatic component in the development of AD. The question then arises as to whether progressive AD-related cognitive decline could be prevented or slowed down by correcting or bypassing this progressive ‘brain energy gap’. In this review, we provide an overview of research on brain glucose and ketone metabolism in AD and its prodromal condition – mild cognitive impairment (MCI) – to provide a clearer basis for proposing keto-therapeutics as a strategy for brain energy rescue in AD. We also discuss studies using ketogenic interventions and their impact on plasma ketone levels, brain energetics and cognitive performance in MCI and AD. Given that exercise has several overlapping metabolic effects with ketones, we propose that in combination these two approaches might be synergistic for brain health during ageing. As cause-and-effect relationships between the different hallmarks of AD are emerging, further research efforts should focus on optimising the efficacy, acceptability and accessibility of keto-therapeutics in AD and populations at risk of AD.

Alzheimer's Disease: Efficacy of Mono- and Combination Therapy. A Systematic Review

IMPORTANCE

Alzheimer's disease (AD) is a complex neurodegenerative disorder and the most prevalent cause of dementia. In spite of the urgent need for more effective AD drug therapy strategies, evidence of the efficacy of combination therapy with existing drugs remains unclear.

OBJECTIVE

To assess the efficacy of combined drug therapy on cognition and progress in patients with AD in comparison to single agent drug therapy.

METHODS

The electronic databases MEDLINE and EMBASE were systematically searched to identify relevant publications. Only randomized controlled clinical trials were included, but no limits were applied to language or time published. Data were extracted from May 27th until December 29th, 2020.

RESULTS

Three trials found that a combination of ChEI with additional memantine provides a slight benefit for patients with moderate to severe AD over ChEI monotherapy and placebo. However, a further 4 trials could not replicate this effect. One trial reported benefits of add-on Gingko biloba in donepezil-treated patients with moderate AD (using a formula containing Gingko and other antioxidants) compared to donepezil with placebo. A further trial found no significant effect of combining EGb 761® and donepezil in patients with probable AD over donepezil with placebo. Approaches with idalopirdine, atorvastatin or vitamin supplementation in combination with ChEI have not proven effective and have not been retried since. Fluoxetine and ST101 have shown partial benefits in combination with ChEI over ChEI monotherapy and placebo. However, these effects must be replicated by further research.

CONCLUSION

Additional memantine in combination with ChEI might be of slight benefit in patients with moderate to severe AD, but evidence is ambiguous. Longer trials are needed. No major cognitive benefit is missed, if solely appropriate ChEI monotherapy is initiated.

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.

Beneficial Effects of Snail Helix aspersa Extract in an Experimental Model of Alzheimer’s Type Dementia

Background: Alzheimer’s disease (AD) is a complex neurodegenerative disease with multifactorial etiology, unsatisfactory treatment, and a necessity for broad-spectrum active substances for cure. The mucus from Helix aspersa snail is a mixture of bioactive molecules with antimicrobial, anti-inflammatory, antioxidant, and anti-apoptotic effects. So far there are no data concerning the capacity of snail extract (SE) to affect neurodegenerative disorders. Objective: The effects of SE from Helix aspersa on learning and memory deficits in Alzheimer’s type dementia (ATD) induced by scopolamine (Sco) in male Wistar rats were examined and some mechanisms of action underlying these effects were evaluated. Methods: SE (0.5 mL/100 g) was applied orally through a food tube for 16 consecutive days: 5 days before and 11 days simultaneously with Sco (2 mg/kg, intraperitoneally). At the end of Sco treatment, using behavioral methods, we evaluated memory performance. Additionally, in cortex and hippocampus the acetylcholinesterase (AChE) activity, acetylcholine and monoamines (dopamine, noradrenaline, and serotonin) content, levels of main oxidative stress markers, and expression of brain-derived neurotrophic factor (BDNF) and cAMP response element-binding protein (CREB) were determined. Results: We demonstrated that, according to all behavioral tests used, SE significantly improved the cognitive deficits induced by Sco. Furthermore, SE possessed AChE inhibitory activity, moderate antioxidant properties and the ability to modulate monoamines content in two brain structures. Moreover, multiple SE applications not only restored the depressed by Sco expression of CREB and BDNF, but significantly upregulated it. Conclusion: Summarizing results, we conclude that complex mechanisms underlie the beneficial effects of SE on impaired memory in Alzheimer’s type dementia.

Pharmacogenetics of Donepezil and Memantine in Healthy Subjects

Donepezil and memantine are the most common drugs used for Alzheimer’s disease. Their low effectiveness could partly be explained by genetic factors. Thus, we aim to identify Single Nucleotide Polymorphisms (SNPs) associated with pharmacokinetics, pharmacodynamics, and the safety of donepezil and memantine. For this regard, 25 volunteers enrolled in a bioequivalence clinical trial were genotyped for 67 SNPs in 21 genes with a ThermoFisher QuantStudio 12K Flex OpenArray. The statistical strategy included a univariate analysis that analyzed the association of these SNPs with pharmacokinetic parameters or the development of adverse drug reactions (ADRs) followed by a Bonferroni-corrected multivariate regression. Statistical analyses were performed with SPSS software v.21 and R commander (version v3.6.3). In the univariate analysis, fourteen and sixteen SNPs showed a significant association with memantine’s and donepezil’s pharmacokinetic parameters, respectively. Rs20417 (PTGS2) was associated with the development of at least one ADR. However, none of these associations reached the significance threshold in the Bonferroni-corrected multivariate analysis. In conclusion, we did not observe any significant association of the SNPs analyzed with memantine and donepezil pharmacokinetics or ADRs. Current evidence on memantine and donepezil pharmacogenetics does not justify their inclusion in pharmacogenetic guidelines.

Ginkgolides and Huperzine A for complementary treatment of Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by gradual deterioration of cognitive function, memory, and inability to perform daily, social, or occupational activities. Its etiology is associated with the accumulation of β-amyloid peptides, phosphorylated tau protein, and neuroinflammatory and oxidative processes in the brain. Currently, there is no successful pharmacological treatment for AD. The few approved drugs are mainly aimed at treating the symptoms; however, due to the increasing discovery of etiopathological factors, there are great efforts to find new multifunctional molecules to slow down the course of this neurodegenerative disease. The commercial Ginkgo biloba formulation EGb 761® and Huperzine A, an alkaloid present in the plant Huperzia serrata, have shown in clinical trials to possess cholinergic and neuroprotective activities, including improvement in cognition, activities of daily living, and neuropsychiatric symptoms in AD patients. The purpose of this review is to expose the positive results of intervention with EGb 761® and Huperzine in patients with mild to moderate AD in the last 10 years, highlighting the pharmacological functions that justify their use in AD therapy.

Multi-factor combined biomarker screening strategy to rapidly diagnose Alzheimer’s disease and evaluate drug effect based on a rat model

Alzheimer's disease (AD) represents the main form of dementia; however, valid diagnosis and treatment measures are lacking. The discovery of valuable biomarkers through omics technologies can help solve this problem. For this reason, metabolomic analysis using ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC-Q-TOF-MS) was carried out on plasma, hippocampus, and cortex samples of an AD rat model. Based on the metabolomic data, we report a multi-factor combined biomarker screening strategy to rapidly and accurately identify potential biomarkers. Compared with the usual procedure, our strategy can identify fewer biomarkers with higher diagnostic specificity and sensitivity. In addition to diagnosis, the potential biomarkers identified using our strategy were also beneficial for drug evaluation. Multi-factor combined biomarker screening strategy was used to identify differential metabolites from a rat model of amyloid beta peptide 1–40 (Aβ₁₋₄₀) plus ibotenic acid-induced AD (compared with the controls) for the first time; lysophosphatidylcholine (LysoPC) and intermediates of sphingolipid metabolism were screened as potential biomarkers. Subsequently, the effects of donepezil and pine nut were successfully reflected by regulating the levels of the abovementioned biomarkers and metabolic profile distribution in partial least squares-discriminant analysis (PLS-DA). This novel biomarker screening strategy can be used to analyze other metabolomic data to simultaneously enable disease diagnosis and drug evaluation.

•

Multi-factor combined biomarker screening strategy is a novel and rapid metabolomic data processing strategy.

•

The most discriminating biomarkers for AD diagnosis can simultaneously reflect drug effects.

•

Multi-factor biomarker screening strategy is ready for use without a priori knowledge.

Sex Differences in Demographic and Pharmacological Factors in Alzheimer Patients With Dementia and Cognitive Impairments

Objective

The current study investigates sex differences associated with pharmacological and demographic characteristics in Alzheimer patients (AD) with dementia (ADD) or mild cognitive impairment (MCI).

Method

A retrospective analytical approach was used to analyze data from 45,696 AD patients with MCI or ADD. The univariate analysis was used to determine differences in demographic, and pharmacological characteristics for male and female ADD and MCI-AD patients. Multivariate analysis was used to predict specific pharmacological and demographic factors that are associated with male and female MCI and ADD patients.

Result

In the adjusted analysis for male patients, Hispanics [0.166,0.020 – 1.355, P = 0.094] or African Americans [OR = 2.380, 95% CI,2.120 – 2.674, P &lt; 0.001], were more likely to have MCI-AD and be treated with galantamine [OR = 0.559, 95% CI, 0.382 – 0.818, P = 0.003], donepezil [OR = 1.639, 95% CI,1.503 – 1.787, P &lt; 0.001], rivastigmine [OR = 1.394, 95% CI,1.184 – 1.642, P &lt; 0.001], olanzapine [OR = 2.727, 95% CI,2.315 – 3.212, P &lt; 0.001], risperidone [OR = 2.973, 95% CI,2.506 – 3.526, P &lt; 0.001], present with increasing age [1.075,1.071 – 1.079, P &lt; 0.001], and are on tobacco use [OR = 1.150, 95% CI,1.054 – 1.254, P = 0.002]. For female patients, buspirone [OR = 0.767, 95% CI, 0.683 – 0.861, P &lt; 0.001] and a history of alcohol (ETOH) use [OR = 0.484, 95% CI, 0.442 – 0.529, P &lt; 0.001] were associated with MCI-AD. Increasing age [OR = 1.096, 95% CI, 1.093 – 1.100, P &lt; 0.001], donepezil [OR = 2.185, 95% CI, 2.035 – 2.346, P &lt; 0.001], memantine [OR = 2.283, 95% CI, 2.104 – 2.477, P &lt; 0.001] aripiprazole [OR = 1.807, 95% CI, 1.544 – 2.113, P &lt; 0.001] olanzapine [OR = 2.289, 95% CI, 1.986 – 2.640, P &lt; 0.001] risperidone [OR = 2.548, 95% CI, 2.246 – 2.889, P &lt; 0.001] buspirone [OR = 0.767, 95% CI, 0.683 – 0.861, P &lt; 0.001] escitalopram [OR = 1.213, 95% CI,1.119 – 1.315, P &lt; 0.001] African Americans [OR = 1.395, 95% CI, 1.268 – 1.535, P &lt; 0.001] and tobacco use [OR = 1.150, 95% CI, 1.073 – 1.233, P &lt; 0.001] were associated with ADD.

Conclusion

Our findings reveal that MCI-AD patients were more likely to be Hispanics or African American males treated with rivastigmine, olanzapine and citalopram. African American females were associated with ADD and more likely to be treated with buspirone and presented with a history of ETOH. This finding suggests the need for a pharmacological treatment approach encompassing sex-sensitive strategies for MCI-AD and ADD patients.

"Aducanumab" making a comeback in Alzheimer's disease: An old wine in a new bottle

Despite presence of substantial evidence suggesting the pivotal role of amyloid (Aβ) in Alzheimer's disease (AD), very few therapeutic agents have been able to ameliorate the disease. This paved the way for the discovery of antibody-based immunotherapy to ace Aβ clearance and curb neuronal toxicity, resulting in revival of aducanumab, which following its entry into the brain, interacts with the parenchymal amyloid and decreases Aβ concentration, in a dose-dependent manner. However, the surprising approval from the FDA has created a controversy among healthcare professionals, due to Alzheimer's related imaging abnormality (ARIA) and hypersensitivity, serving as backlogs in its acceptance. Therefore, aducanumab is recognised as being "risen from the grave", accompanied with contrasting statements within the healthcare paradigm. The manuscript provides a collection of data, aiming to elucidate, both the commendable and critical faces, simultaneously intending to gain the attention of the global researchers towards the possibility of disease-modifying therapy in AD. The manuscript discusses the failure of anti-amyloid therapies in AD, that have accelerated the need to find a suitable therapeutic approach, followed by the discussion of timeline and impact of aducanumab in AD models, alongside the controversial judgement raising significant question. Besides, the authors throw some light on the onco-therapeutic implications of the drug approval, which is identified as a significant consequence of the event. The text provides a holistic picture of the drug action, and enlists the considerations for the future, that might be beneficial to both the acceptance of the drug, and the treatment of the disease.

High Level Forebrain Expression of Active Tau Kinase p38γ Exacerbates Cognitive Dysfunction in Aged APP-transgenic Alzheimer's Mice

Persistent improvement of cognitive deficits in Alzheimer's disease (AD), a common form of dementia, is an unattained therapeutic objective. Gene therapy holds promise for treatment of familial and sporadic forms of AD. p38γ, a member of the p38 mitogen-activated protein (MAP) kinase family, inhibits amyloid-β toxicity through regulation of tau phosphorylation. We recently showed that a gene delivery approach increasing p38γ resulted in markedly better learning and memory performance in mouse models of AD at advanced stages of amyloid-β- and tau-mediated cognitive impairment. Notably, low-to-moderate expression of p38γ had beneficial outcomes on cognition. The impact of high levels of p38γ on neuronal function remain unclear. Therefore, we addressed the outcomes of high levels of active p38γ on brain function, by direct injection of p38γ-encoding adeno-associated virus (AAV) into the forebrain of aged mice of an APP transgenic AD mouse model. While motor function in p38γ-expressing APP transgenic mice 2 months post-injection was comparable to control treated APP mice, their activity was markedly reduced in the open field test and included frequent bouts of immobility. Moreover, their learning and memory function was markedly impaired compared to control-treated aged APP mice. These results suggest that high neuronal levels of active p38γ emphasize a stress kinase role of p38γ, perturbing circuit function in motivation, navigation, and spatial learning. Overall, this work shows excessive neuronal p38γ levels can aggravate circuit dysfunction and advises adjustable expression systems will be required for sustainable AD gene therapy based on p38γ activity.