Memantine for Alzheimer's Disease: An Updated Systematic Review and Meta-analysis

The Interplay of Protein Aggregation, Genetics, and Oxidative Stress in Alzheimer's Disease: Role for Natural Antioxidants and Immunotherapeutics

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that comprises amyloid-beta protein (Aβ) as a main component of neuritic plaques. Its deposition is considered a trigger for AD pathogenesis, progression, and the clinical symptoms of cognitive impairment. Some distinct pathological features of AD include phosphorylation of tau protein, oxidative stress, and mitochondrial dysfunction. These pathological consequences tend to produce reactive oxygen species (ROS), resulting in the dysregulation of various signaling pathways of neuroinflammation and neurodegeneration. The relationship between the Aβ cascade and oxidative stress in AD pathogenesis is like a "chicken and egg" story, with the etiology of the disease regarding these two factors remaining a question of "which comes first." However, in this review, we have tried our best to clarify the interconnection between these two mechanisms and to show the precise cause-and-effect relationship. Based on the above hallmarks of AD, several therapeutic strategies using natural antioxidants, monoclonal antibodies, and vaccines are employed as anti-Aβ therapy to decrease ROS, Aβ burden, chronic neuroinflammation, and synaptic failure. These natural antioxidants and immunotherapeutics have demonstrated significant neuroprotective effects and symptomatic relief in various in vitro and in vivo models, as well as in clinical trials for AD. However, none of them have received final approval to enter the drug market for mitigating AD. In this review, we extensively elaborate on the pitfalls, assurances, and important crosstalk between oxidative stress and Aβ concerning current anti-Aβ therapy. Additionally, we discuss future strategies for the development of more Aβ-targeted approaches and the optimization of AD treatment and mitigation.

The Inflammation-Induced Dysregulation of Reelin Homeostasis Hypothesis of Alzheimer's Disease

Alzheimer's disease (AD) accounts for most dementia cases, but we lack a complete understanding of the mechanisms responsible for the core pathology associated with the disease (e.g., amyloid plaque and neurofibrillary tangles). Inflammation has been identified as a key contributor of AD pathology, with recent evidence pointing towards Reelin dysregulation as being associated with inflammation. Here we describe Reelin signaling and outline existing research involving Reelin signaling in AD and inflammation. Research is described pertaining to the inflammatory and immunological functions of Reelin before we propose a mechanism through which inflammation renders Reelin susceptible to dysregulation resulting in the induction and exacerbation of AD pathology. Based on this hypothesis, it is predicted that disorders of both inflammation (including peripheral inflammation and neuroinflammation) and Reelin dysregulation (including disorders associated with upregulated Reelin expression and disorders of Reelin downregulation) have elevated risk of developing AD. We conclude with a description of AD risk in various disorders involving Reelin dysregulation and inflammation.

Progress in Pharmacologic Management of Neuropsychiatric Syndromes in Neurodegenerative Disorders: A Review

Importance

Neuropsychiatric syndromes (NPSs) are common in neurodegenerative disorders (NDDs); compromise the quality of life of patients and their care partners; and are associated with faster disease progression, earlier need for nursing home care, and poorer quality of life. Advances in translational pharmacology, clinical trial design and conduct, and understanding of the pathobiology of NDDs are bringing new therapies to clinical care.

Observations

Consensus definitions have evolved for psychosis, agitation, apathy, depression, and disinhibition in NDDs. Psychosocial interventions may reduce mild behavioral symptoms in patients with NDD, and pharmacotherapy is available for NPSs in NDDs. Brexpiprazole is approved for treatment of agitation associated with Alzheimer disease dementia, and pimavanserin is approved for treatment of delusions and hallucinations associated with psychosis of Parkinson disease. Trials are being conducted across several of the NDDs, and a variety of mechanisms of action are being assessed for their effect on NPSs.

Conclusions and Relevance

Detection and characterization of NPSs in patients with NDDs is the foundation for excellent care. New definitions for NPSs in NDDs may inform choices regarding clinical trial populations and translate into clinical practice. Psychosocial and pharmacologic therapies may reduce behavioral symptoms and improve quality of life for patients and caregivers. Approved agents may establish regulatory precedents, demonstrate successful trial strategies, and provide the foundation for further advances in treatment development.

Cholinesterase inhibitors and memantine are associated with a reduced mortality in nursing home residents with dementia: a longitudinal observational study

BACKGROUND

A large proportion of nursing home (NH) residents suffer from dementia and effects of conventional anti-dementia drugs on their health is poorly known. We aimed to investigate the associations between exposure to anti-dementia drugs and mortality among NH residents.

METHODS

This retrospective longitudinal observational study involved 329 French NH and the residents admitted in these facilities since 2014 and having major neurocognitive disorder. From their electronic health records, we obtained their age, sex, level of dependency, Charlson comorbidity index, and Mini mental examination score at admission. Exposure to anti-dementia drugs was determined using their prescription into 4 categories: none, exposure to acetylcholinesterase inhibitors (AChEI) alone, exposure to memantine alone, exposure to AChEI and memantine. Survival until the end of 2019 was studied in the entire cohort by Cox proportional hazards. To alleviate bias related to prescription of anti-dementia drugs, we formed propensity-score matched cohorts for each type of anti-dementia drug exposure, and studied survival by the same method.

RESULTS

We studied 25,358 NH residents with major neurocognitive disorder. Their age at admission was 87.1 + 7.1 years and 69.8% of them were women. Exposure to anti-dementia drugs occurred in 2,550 (10.1%) for AChEI alone, in 2,055 (8.1%) for memantine alone, in 460 (0.2%) for AChEI plus memantine, whereas 20,293 (80.0%) had no exposure to anti-dementia drugs. Adjusted hazard ratios for mortality were significantly reduced for these three groups exposed to anti-dementia drugs, as compared to reference group: HR: 0.826, 95%CI 0.769 to 0.888 for AChEI; 0.857, 95%CI 0.795 to 0.923 for memantine; 0.742, 95%CI 0.640 to 0.861 for AChEI plus memantine. Results were consistent in propensity-score matched cohorts.

CONCLUSION

The use of conventional anti-dementia drugs is associated with a lower mortality in nursing home residents with dementia and should be widely used in this population.

Alzheimer's disease and its treatment-yesterday, today, and tomorrow

Alois Alzheimer described the first patient with Alzheimer's disease (AD) in 1907 and today AD is the most frequently diagnosed of dementias. AD is a multi-factorial neurodegenerative disorder with familial, life style and comorbidity influences impacting a global population of more than 47 million with a projected escalation by 2050 to exceed 130 million. In the USA the AD demographic encompasses approximately six million individuals, expected to increase to surpass 13 million by 2050, and the antecedent phase of AD, recognized as mild cognitive impairment (MCI), involves nearly 12 million individuals. The economic outlay for the management of AD and AD-related cognitive decline is estimated at approximately 355 billion USD. In addition, the intensifying prevalence of AD cases in countries with modest to intermediate income countries further enhances the urgency for more therapeutically and cost-effective treatments and for improving the quality of life for patients and their families. This narrative review evaluates the pathophysiological basis of AD with an initial focus on the therapeutic efficacy and limitations of the existing drugs that provide symptomatic relief: acetylcholinesterase inhibitors (AChEI) donepezil, galantamine, rivastigmine, and the N-methyl-D-aspartate receptor (NMDA) receptor allosteric modulator, memantine. The hypothesis that amyloid-β (Aβ) and tau are appropriate targets for drugs and have the potential to halt the progress of AD is critically analyzed with a particular focus on clinical trial data with anti-Aβ monoclonal antibodies (MABs), namely, aducanumab, lecanemab and donanemab. This review challenges the dogma that targeting Aβ will benefit the majority of subjects with AD that the anti-Aβ MABs are unlikely to be the "magic bullet". A comparison of the benefits and disadvantages of the different classes of drugs forms the basis for determining new directions for research and alternative drug targets that are undergoing pre-clinical and clinical assessments. In addition, we discuss and stress the importance of the treatment of the co-morbidities, including hypertension, diabetes, obesity and depression that are known to increase the risk of developing AD.

Early- and Late-Onset Alzheimer's Disease: Two Sides of the Same Coin?

Early-onset Alzheimer's disease (EOAD), defined as Alzheimer's disease onset before 65 years of age, has been significantly less studied than the "classic" late-onset form (LOAD), although EOAD often presents with a more aggressive disease course, caused by variants in the APP, PSEN1, and PSEN2 genes. EOAD has significant differences from LOAD, including encompassing diverse phenotypic manifestations, increased genetic predisposition, and variations in neuropathological burden and distribution. Phenotypically, EOAD can be manifested with non-amnestic variants, sparing the hippocampi with increased tau burden. The aim of this article is to review the different genetic bases, risk factors, pathological mechanisms, and diagnostic approaches between EOAD and LOAD and to suggest steps to further our understanding. The comprehension of the monogenic form of the disease can provide valuable insights that may serve as a roadmap for understanding the common form of the disease.

In silico and pharmacokinetic studies of glucomoringin from Moringa oleifera root for Alzheimer's disease like pathology

Aim: The aim of this research is to investigate the potential of glucomoringin, derived from Moringa oleifera, as a therapeutic agent for Alzheimer's disease through in silico analysis. Materials & methods: This study employs in silico or computational methodologies, including pkCSM, Swiss ADME, OSIRIS® property explorer, PASS online web resource and MOLINSPIRATION® software, to predict the pharmacokinetic characteristics and biological activity of glucomoringin. Results & conclusion: Molecular docking indicates strong binding to I-1β and the pharmacokinetic profile shows cytochrome P450 enzyme inhibition, prompting further research for dosing strategies. Toxicological predictions affirm safety, while bioactivity assessments demonstrate versatility in modulating essential pathways. glucomoringin's potential for Alzheimer's treatment, emphasizing the need for additional empirical research.

Review on anti-alzheimer drug development: approaches, challenges and perspectives

Alzheimer is an irreversible progressive neurodegenerative disease that causes failure of cerebral neurons and disability of the affected person to practice normal daily life activities. There is no concrete evidence to identify the exact reason behind the disease, so several relevant hypotheses emerged, highlighting many possible therapeutic targets, such as acetylcholinesterase, cholinergic receptors, N-methyl d-aspartate receptors, phosphodiesterase, amyloid β protein, protein phosphatase 2A, glycogen synthase kinase-3 beta, β-secretase, γ-secretase, α-secretase, serotonergic receptors, glutaminyl cyclase, tumor necrosis factor-α, γ-aminobutyric acid receptors, and mitochondria. All of these targets have been involved in the design of new potential drugs. An extensive number of these drugs have been studied in clinical trials. However, only galantamine, donepezil, and rivastigmine (ChEIs), memantine (NMDA antagonist), and aducanumab and lecanemab (selective anti-Aβ monoclonal antibodies) have been approved for AD treatment. Many drugs failed in the clinical trials to such an extent that questions have been posed about the significance of some of the aforementioned targets. On the contrary, the data of other drugs were promising and shed light on the significance of their targets for the development of new potent anti-alzheimer drugs.

Classic Famous Prescription Kai-Xin-San Ameliorates Alzheimer's Disease via the Wnt/β-Catenin Signaling Pathway

Kai-Xin-San (KXS) is a classic famous prescription composed of Polygalae Radix, Ginseng Radix et Rhizoma, Acori Tatarinowii Rhizoma, and Poria. Clinically, KXS is effective in treating amnesia and regulating cognitive dysfunction of Alzheimer's disease (AD), whereas its mechanism of action is still unclear. In this study, the AD model rats were established by combining intraperitoneal injection of D-galactose (150 mg/kg/day) and intracerebral injection of Aβ25-35 (10 μL) to investigate the meliorative effect of KXS on AD and explore its mechanism. After 1-month KXS treatment, Morris water maze test showed that different doses of KXS all improved the cognitive impairment of AD rats. The results of hematoxylin and eosin staining, Nissl staining, and Tunnel staining showed that the neuron injury in the hippocampal CA1 region of the AD rats was markedly improved after KXS treatment. Concurrently, KXS reversed the levels of biochemical indexes of AD rats. Furthermore, the protein expressions of Wnt1 and β-catenin in KXS groups were remarkably increased, while the expressions of Bax and caspase-3 were significantly decreased. Besides, KXS-medicated serum reduced the levels of tumor necrosis factor-α, interleukin-1β, and reactive oxygen species and regulated the protein expressions of β-catenin, glycogen synthase kinase-3β (GSK-3β), p-GSK-3β, Bax, and caspase-3 in Aβ25-35-induced pheochromocytoma cells. Most importantly, this effect was attenuated by the Wnt inhibitor IWR-1. Our results suggest that KXS improves cognitive and memory function of AD rats, and its neuroprotective mechanism may be mediated through the Wnt/β-catenin signaling pathway.

Personalized, Precision Medicine to Cure Alzheimer's Dementia: Approach #1

The goal of the treatment for Alzheimer's dementia (AD) is the cure of dementia. A literature review revealed 18 major elements causing AD and 29 separate medications that address them. For any individual with AD, one is unlikely to discern which major causal elements produced dementia. Thus, for personalized, precision medicine, all causal elements must be treated so that each individual patient will have her or his causal elements addressed. Twenty-nine drugs cannot concomitantly be administered, so triple combinations of drugs taken from that list are suggested, and each triple combination can be administered sequentially, in any order. Ten combinations given over 13 weeks require 2.5 years, or if given over 26 weeks, they require 5.0 years. Such sequential treatment addresses all 18 elements and should cure dementia. In addition, any comorbid risk factors for AD whose first presence or worsening was within ±1 year of when AD first appeared should receive appropriate, standard treatment together with the sequential combinations. The article outlines a randomized clinical trial that is necessary to assess the safety and efficacy of the proposed treatments; it includes a triple-drug Rx for equipoise. Clinical trials should have durations of both 2.5 and 5.0 years unless the data safety monitoring board (DSMB) determines earlier success or futility since it is uncertain whether three or six months of treatment will be curative in humans, although studies in animals suggest that the briefer duration of treatment might be effective and restore defective neural tracts.

Structure-based inhibition of acetylcholinesterase and butyrylcholinesterase with 2-Aryl-6-carboxamide benzoxazole derivatives: synthesis, enzymatic assay, and in silico studies

An important research topic is the discovery of multifunctional compounds targeting different disease-causing components. This research aimed to design and synthesize a series of 2-aryl-6-carboxamide benzoxazole derivatives that inhibit cholinesterases on both the peripheral anionic and catalytic anionic sides. Compounds (7-48) were prepared from 4-amino-3-hydroxybenzoic acid in three steps. The Ellman test, molecular docking with Maestro, and molecular dynamics simulation studies with Desmond were done (Schrodinger, 12.8.117). Compound 36, the most potent compound among the 42 new compounds synthesized, had an inhibitory concentration of IC50 12.62 nM for AChE and IC50 25.45 nM for BChE (whereas donepezil was 69.3 nM and 63.0 nM, respectively). Additionally, compound 36 had docking values ​​of - 7.29 kcal/mol for AChE and - 6.71 kcal/mol for BChE (whereas donepezil was - 6.49 kcal/mol and - 5.057 kcal/mol, respectively). Furthermore, molecular dynamics simulations revealed that compound 36 is stable in the active gorges of both AChE (average RMSD: 1.98 Å) and BChE (average RMSD: 2.2 Å) (donepezil had average RMSD: 1.65 Å and 2.7 Å, respectively). The results show that compound 36 is a potent, selective, mixed-type dual inhibitor of both acetylcholinesterase and butyrylcholinesterase. It does this by binding to both the catalytically active and peripheral anionic sites of cholinesterases at the same time. These findings show that target compounds may be useful for establishing the structural basis for new anti-Alzheimer agents.

Paeonol Derivative, 6'-Methyl Paeonol, Attenuates Aβ-Induced Pathophysiology in Cortical Neurons and in an Alzheimer's Disease Mice Model

Herbs themselves and various herbal medicines are great resources for discovering therapeutic drugs for various diseases, including Alzheimer's disease (AD), one of the common neurodegenerative diseases. Utilizing mouse primary cortical neurons and DiBAC4(3), a voltage-sensitive indicator, we have set up a drug screening system and identified an herbal extraction compound, paeonol, obtained from Paeonia lactiflora; this compound is able to ameliorate the abnormal depolarization induced by Aβ42 oligomers. Our aim was to further find effective paeonol derivatives since paeonol has been previously studied. 6'-Methyl paeonol, one of the six paeonol derivatives surveyed, is able to inhibit the abnormal depolarization induced by Aβ oligomers. Furthermore, 6'-methyl paeonol is able to alleviate the NMDA- and AMPA-induced depolarization. When a molecular mechanism was investigated, 6'-methyl paeonol was found to reverse the Aβ-induced increase in ERK phosphorylation. At the animal level, mice injected with 6'-methyl paeonol showed little change in their basic physical parameters compared to the control mice. 6'-Methyl paeonol was able to ameliorate the impairment of memory and learning behavior in J20 mice, an AD mouse model, as measured by the Morris water maze. Thus, paeonol derivatives could provide a structural foundation for developing and designing an effective compound with promising clinical benefits.

Effect of hormone replacement therapy on amyloid beta (Aβ) plaque density in the rhesus macaque amygdala

Background

Amyloid beta (Aβ) plaque density was examined in the amygdala of rhesus macaques, to elucidate the influence of age, diet and hormonal environment.

Methods

Luminex technology was used to measure cerebrospinal fluid (CSF) concentrations of Aβ40 and Aβ42 across three decades, while immunohistochemistry was used to examine Aβ plaque density in the amygdala.

Results

Aβ40 was found to be the predominant isoform of Aβ in the CSF, but neither Aβ40 or Aβ42 concentrations showed an age-related change, and the ratio of Aβ42 to Aβ40 showed only a marginal increase. Significantly fewer Aβ plaques were detected in the amygdala of old ovariectomized animals if they received estradiol HRT (p < 0.001); similar results were obtained regardless of whether they had been maintained on a regular monkey chow for ∼48 months or on a high-fat, high-sugar, Western-style diet for ∼30 months.

Conclusion

The results demonstrate that HRT involving estrogen can reduce Aβ plaque load in a cognitive brain region of aged non-human primates. The results from this translational animal model may therefore have clinical relevance to the treatment of AD in post-menopausal women, whether used alone, or as a supplement to current pharmacological and monoclonal antibody-based interventions.

Glutamate's Effects on the N-Methyl-D-Aspartate (NMDA) Receptor Ion Channel in Alzheimer's Disease Brain: Challenges for PET Radiotracer Development for Imaging the NMDA Ion Channel

In an effort to further understand the challenges facing in vivo imaging probe development for the N-methyl-D-aspartate (NMDA) receptor ion channel, we have evaluated the effect of glutamate on the Alzheimer's disease (AD) brain. Human post-mortem AD brain slices of the frontal cortex and anterior cingulate were incubated with [3H]MK-801 and adjacent sections were tested for Aβ and Tau. The binding of [3H]MK-801 was measured in the absence and presence of glutamate and glycine. Increased [3H]MK-801 binding in AD brains was observed at baseline and in the presence of glutamate, indicating a significant increase (>100%) in glutamate-induced NMDA ion channel activity in AD brains compared to cognitively normal brains. The glycine effect was lower, suggesting a decrease of the co-agonist effect of glutamate and glycine in the AD brain. Our preliminary findings suggest that the targeting of the NMDA ion channel as well as the glutamate site may be appropriate in the diagnosis and treatment of AD. However, the low baseline levels of [3H]MK-801 binding in the frontal cortex and anterior cingulate in the absence of glutamate and glycine indicate significant hurdles for in vivo imaging probe development and validation.

Chronic memantine disrupts spatial memory and up-regulates Htr1a gene expression in the hippocampus of GPR39 (zinc-sensing receptor) KO male mice

GPR39 is a receptor involved in zincergic neurotransmission, and its role in regulating psychological functions is an active area of research. The purported roles of GPR39 at the cellular level include regulation of inflammatory and oxidative stress response, and modulation of GABAergic and endocannabinoid neurotransmission. GPR39 knock-out (KO) mice exhibit episodic-like and spatial memory (ELM and SM, respectively) deficits throughout their lifetime, and are similar in that respect to senescent wild-type (WT) conspecifics. Since a role for zinc has been postulated in neurodegenerative disorders, in this study we investigated the possibility of a pharmacological rescue of both types of declarative memory with memantine - a noncompetitive NMDAR antagonist used for slowing down dementia; or, a putative GPR39 agonist - TC-G 1008. First, we tested adult WT and GPR39KO male mice under acute 5 mg/kg memantine or vehicle treatment in an object recognition task designed to simultaneously probe the "what?", "where?" and "when?" components of ELM. Next, we investigated the impact of chronic memantine or TC-G 1008 on ELM and SM (Morris water maze, MWM) in both WT and GPR39KO mice. Following chronic experiments, we assessed with qRT-PCR hippocampal gene expression of targets previously associated with GPR39. We report: no effects of acute memantine on ELM; a tendency to improve the "where?" component of ELM in both WT and GPR39 KO mice following 12 days of memantine; and, a disruption of SM in GPR39KO mice after 24 days of memantine treatment. The latter result was associated with upregulation of Htr1a hippocampal expression.

Functional brain region-specific neural spheroids for modeling neurological diseases and therapeutics screening

3D spheroids have emerged as powerful drug discovery tools given their high-throughput screening (HTS) compatibility. Here, we describe a method for generating functional neural spheroids by cell-aggregation of differentiated human induced pluripotent stem cell (hiPSC)-derived neurons and astrocytes at cell type compositions mimicking specific regions of the human brain. Recordings of intracellular calcium oscillations were used as functional assays, and the utility of this spheroids system was shown through disease modeling, drug testing, and formation of assembloids to model neurocircuitry. As a proof of concept, we generated spheroids incorporating neurons with Alzheimer's disease-associated alleles, as well as opioid use disorder modeling spheroids induced by chronic treatment of a mu-opioid receptor agonist. We reversed baseline functional deficits in each pilot disease model with clinically approved treatments and showed that assembloid activity can be chemogenetically manipulated. Here, we lay the groundwork for brain region-specific neural spheroids as a robust functional assay platform for HTS studies.

Pharmacogenomics of Dementia: Personalizing the Treatment of Cognitive and Neuropsychiatric Symptoms

Dementia is a syndrome of global and progressive deterioration of cognitive skills, especially memory, learning, abstract thinking, and orientation, usually affecting the elderly. The most common forms are Alzheimer's disease, vascular dementia, and other (frontotemporal, Lewy body disease) dementias. The etiology of these multifactorial disorders involves complex interactions of various environmental and (epi)genetic factors and requires multiple forms of pharmacological intervention, including anti-dementia drugs for cognitive impairment, antidepressants, antipsychotics, anxiolytics and sedatives for behavioral and psychological symptoms of dementia, and other drugs for comorbid disorders. The pharmacotherapy of dementia patients has been characterized by a significant interindividual variability in drug response and the development of adverse drug effects. The therapeutic response to currently available drugs is partially effective in only some individuals, with side effects, drug interactions, intolerance, and non-compliance occurring in the majority of dementia patients. Therefore, understanding the genetic basis of a patient's response to pharmacotherapy might help clinicians select the most effective treatment for dementia while minimizing the likelihood of adverse reactions and drug interactions. Recent advances in pharmacogenomics may contribute to the individualization and optimization of dementia pharmacotherapy by increasing its efficacy and safety via a prediction of clinical outcomes. Thus, it can significantly improve the quality of life in dementia patients.

Novel therapeutic strategies in glioma targeting glutamatergic neurotransmission

High grade gliomas carry a poor prognosis despite aggressive surgical and adjuvant approaches including chemoradiotherapy. Recent studies have demonstrated a mitogenic association between neuronal electrical activity and glioma growth involving the PI3K-mTOR pathway. As the predominant excitatory neurotransmitter of the brain, glutamate signalling in particular has been shown to promote glioma invasion and growth. The concept of the neurogliomal synapse has been established whereby glutamatergic receptors on glioma cells have been shown to promote tumour propagation. Targeting glutamatergic signalling is therefore a potential treatment option in glioma. Antiepileptic medications decrease excess neuronal electrical activity and some may possess anti-glutamate effects. Although antiepileptic medications continue to be investigated for an anti-glioma effect, good quality randomised trial evidence is lacking. Other pharmacological strategies that downregulate glutamatergic signalling include riluzole, memantine and anaesthetic agents. Neuromodulatory interventions possessing potential anti-glutamate activity include deep brain stimulation and vagus nerve stimulation - this contributes to the anti-seizure efficacy of the latter and the possible neuroprotective effect of the former. A possible role of neuromodulation as a novel anti-glioma modality has previously been proposed and that hypothesis is extended to include these modalities. Similarly, the significant survival benefit in glioblastoma attributable to alternating electrical fields (Tumour Treating Fields) may be a result of disruption to neurogliomal signalling. Further studies exploring excitatory neurotransmission and glutamatergic signalling and their role in glioma origin, growth and propagation are therefore warranted.

[Telemedicine Care of Dementia Patients During the COVID-19 Pandemic]

In our multidisciplinary memory center at Jena University Hospital, we initiated a regular video consultation for patients at risk of developing dementia or with dementia disease and their relatives at the beginning of the SARS-CoV2 pandemic in spring 2020.Over a 12-month period, we conducted a systematic survey of satisfaction among patients in regular face-to-face contact (F2F) and video consultations (VC).The aim of this study was to evaluate the potential use of telemedicine in older people with incipient cognitive deficits in the context of dementia. In particular, we aimed to evaluate patient satisfaction and feasibility.Initial presentations to our memory center for suspected dementia were evaluated in a standardized regular on-site setting (n=50) and in a standardized video consultation (n=40). In both settings, a neuropsychologist's and a physician's consultation were performed consecutively. Both groups were similarly distributed in terms of age and sex (71.4 vs. 72.3 years, 52 vs. 50% female (F2F vs. VC)). Cognitive status was slightly better in the VC group (ACE III significant, MMST not significant).In the survey of the patients using a 12-question inventory (patient satisfaction, rated 1 to 5), there was no significant difference between the two groups overall. However, the F2F tended to be rated slightly better here in terms of advice. More than 80% of the physicians and neuropsychologists rated the technical process of VC as good/very good.A general assessment of the cognitive deficits by physicians and neuropsychologists correlated extremely highly with the results of the subsequent specific testing (MMST and ACE) in F2F and VC. With a tendency to better agreement in VC, the difference between the correlations was not significant.Overall, we could not find any significant differences in patients' satisfaction between VC and classical F2F presentation. Technical aspects in the preparation of a VC and during a VC were less problematic than initially anticipated.

A causal inference study: The impact of the combined administration of Donepezil and Memantine on decreasing hospital and emergency department visits of Alzheimer's disease patients

Alzheimer's disease is the most common type of dementia that currently affects over 6.5 million people in the U.S. Currently there is no cure and the existing drug therapies attempt to delay the mental decline and improve cognitive abilities. Two of the most commonly prescribed such drugs are Donepezil and Memantine. We formally tested and confirmed the presence of a beneficial drug-drug interaction of Donepezil and Memantine using a causal inference analysis. We applied doubly robust estimators to one of the largest and high-quality medical databases to estimate the effect of two commonly prescribed Alzheimer's disease (AD) medications, Donepezil and Memantine, on the average number of hospital or emergency department visits per year among patients diagnosed with AD. Our results show that, compared to the absence of medication scenario, the Memantine monotherapy, and the Donepezil monotherapy, the combined use of Donepezil and Memantine treatment significantly reduces the average number of hospital or emergency department visits per year by 0.078 (13.8%), 0.144 (25.5%), and 0.132 days (23.4%), respectively. The assessed decline in the average number of hospital or emergency department visits per year is consequently associated with a substantial reduction in medical costs. As of 2022, according to the Alzheimer's Disease Association, there were over 6.5 million individuals aged 65 and older living with AD in the US alone. If patients who are currently on no drug treatment or using either Donepezil or Memantine alone were switched to the combined used of Donepezil and Memantine therapy, the average number of hospital or emergency department visits could decrease by over 613 thousand visits per year. This, in turn, would lead to a remarkable reduction in medical expenses associated with hospitalization of AD patients in the US, totaling over 940 million dollars per year.

Hydroxytyrosol-Donepezil Hybrids Play a Protective Role in an In Vitro Induced Alzheimer's Disease Model and in Neuronal Differentiated Human SH-SY5Y Neuroblastoma Cells

Alzheimer's disease (AD) is the most common neurodegenerative pathology among progressive dementias, and it is characterized by the accumulation in the brain of extracellular aggregates of beta-amyloid proteins and neurofibrillary intracellular tangles consisting of τ-hyperphosphorylated proteins. Under normal conditions, beta-amyloid peptides exert important trophic and antioxidant roles, while their massive presence leads to a cascade of events culminating in the onset of AD. The fibrils of beta-amyloid proteins are formed by the process of fibrillogenesis that, starting from individual monomers of beta-amyloid, can generate polymers of this protein, constituting the hypothesis of the "amyloid cascade". To date, due to the lack of pharmacological treatment for AD without toxic side effects, chemical research is directed towards the realization of hybrid compounds that can act as an adjuvant in the treatment of this neurodegenerative pathology. The hybrid compounds used in this work include moieties of a hydroxytyrosol, a nitrohydroxytyrosol, a tyrosol, and a homovanillyl alcohol bound to the N-benzylpiperidine moiety of donepezil, the main drug used in AD. Previous experiments have shown different properties of these hybrids, including low toxicity and antioxidant and chelating activities. The purpose of this work was to test the effects of hybrid compounds mixed with Aβ1-40 to induce fibrillogenesis and mimic AD pathogenesis. This condition has been studied both in test tubes and by an in vitro model of neuronal differentiated human SH-SY5Y neuroblastoma cells. The results obtained from test tube experiments showed that some hybrids inhibit the activity of the enzymes AChE, BuChE, and BACE-1. Cell experiments suggested that hybrids could inhibit fibrillogenesis, negatively modulating caspase-3. They were also shown to exert antioxidant effects, and the acetylated hybrids were found to be more functional and efficient than nonacetylated forms.

Investigation of Cognitive Impairment in the Course of Post-COVID Syndrome

(1) Background: The study presents results from an investigation of cognitive impairment in patients hospitalized in the first psychiatric clinic in Bulgaria to treat patients with COVID-19 during the pandemic period between 2020 and 2022. One hundred and twenty patients who had recovered from acute COVID-19 infection (up to 12 weeks ago) and had no previous history of cognitive impairment participated in the study. In 23 of them (19.17%), disturbance of cognitive functioning was observed. (2) Methods: All 23 patients underwent neuropsychological (Luria's test, Platonov's Maze test, MMSE, Boston Naming test) and neuroimaging examinations. Only seven of them had evidence of cortical atrophy on CT/MRI images. The most significantly demonstrative image of one of those patients is presented. (3) Results: The neuropsychological testing results of both groups show a certain decrease in fixation and memory retention as well as in the range, concentration, distribution and switching of attention. Deviations from the norm on the MMSE, as well as on the Boston Naming Test, were found in the group of patients with cortical atrophy (mild to moderate aphasia). Neuroprotective agents such as Citicoline, Piracetam and Memantine were prescribed to the patients with evident cortical atrophy. After 3 months, positive results of the neuropsychological examination were reported in both groups. (4) Conclusions: Although there are limited data on the benefit of prescribing pro-cognitive agents in the post-COVID period, our clinical experience suggests that it might be useful in the recovery process from the infection's consequences on cognition for patients with brain pathology.

Evaluation of bumetanide as a potential therapeutic agent for Alzheimer's disease

Therapeutics discovery and development for Alzheimer's disease (AD) has been an area of intense research to alleviate memory loss and the underlying pathogenic processes. Recent drug discovery approaches have utilized in silico computational strategies for drug candidate selection which has opened the door to repurposing drugs for AD. Computational analysis of gene expression signatures of patients stratified by the APOE4 risk allele of AD led to the discovery of the FDA-approved drug bumetanide as a top candidate agent that reverses APOE4 transcriptomic brain signatures and improves memory deficits in APOE4 animal models of AD. Bumetanide is a loop diuretic which inhibits the kidney Na+-K+-2Cl- cotransporter isoform, NKCC2, for the treatment of hypertension and edema in cardiovascular, liver, and renal disease. Electronic health record data revealed that patients exposed to bumetanide have lower incidences of AD by 35%-70%. In the brain, bumetanide has been proposed to antagonize the NKCC1 isoform which mediates cellular uptake of chloride ions. Blocking neuronal NKCC1 leads to a decrease in intracellular chloride and thus promotes GABAergic receptor mediated hyperpolarization, which may ameliorate disease conditions associated with GABAergic-mediated depolarization. NKCC1 is expressed in neurons and in all brain cells including glia (oligodendrocytes, microglia, and astrocytes) and the vasculature. In consideration of bumetanide as a repurposed drug for AD, this review evaluates its pharmaceutical properties with respect to its estimated brain levels across doses that can improve neurologic disease deficits of animal models to distinguish between NKCC1 and non-NKCC1 mechanisms. The available data indicate that bumetanide efficacy may occur at brain drug levels that are below those required for inhibition of the NKCC1 transporter which implicates non-NKCC1 brain mechansims for improvement of brain dysfunctions and memory deficits. Alternatively, peripheral bumetanide mechanisms may involve cells outside the central nervous system (e.g., in epithelia and the immune system). Clinical bumetanide doses for improved neurological deficits are reviewed. Regardless of mechanism, the efficacy of bumetanide to improve memory deficits in the APOE4 model of AD and its potential to reduce the incidence of AD provide support for clinical investigation of bumetanide as a repurposed AD therapeutic agent.

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.

The Importance of Stem Cells Isolated from Human Dental Pulp and Exfoliated Deciduous Teeth as Therapeutic Approach in Nervous System Pathologies

Despite decades of research, no therapies are available to halt or slow down the course of neuro-degenerative disorders. Most of the drugs developed to fight neurodegeneration are aimed to alleviate symptoms, but none has proven adequate in altering the course of the pathologies. Cell therapy has emerged as an intriguing alternative to the classical pharmacological approach. Cell therapy consists of the transplantation of stem cells that can be obtained from various embryonal and adult tissues. Whereas the former holds notable ethical issue, adult somatic stem cells can be obtained without major concerns. However, most adult stem cells, such as those derived from the bone marrow, are committed toward the mesodermal lineage, and hence need to be reprogrammed to induce the differentiation into the neurons. The discovery of neural crest stem cells in the dental pulp, both in adults' molar and in baby teeth (dental pulp stem cells and stem cells from human exfoliated deciduous teeth, respectively) prompted researchers to investigate their utility as therapy in nervous system disorders. In this review, we recapitulate the advancements on the application of these stem cells in preclinical models of neurodegenerative diseases, highlighting differences and analogies in their maintenance, differentiation, and potential clinical application.

Unfavorable effects of memantine on the skeletal system in female rats

Memantine is an N-methyl-D-aspartate (NMDA) receptor antagonist used in the treatment of Alzheimer's disease (AD). NMDA receptors are expressed on bone cells. The aim of the present study was to investigate the effects of memantine on the rat musculoskeletal system. Taking into account that most of female AD patients are postmenopausal, the study was carried out on intact and ovariectomized (estrogen-deficient) rats. Mature Wistar rats were divided into following groups: non-ovariectomized (NOVX) control rats, NOVX rats treated with memantine, ovariectomized (OVX) control rats, and OVX rats treated with memantine. Memantine (2 mg/kg p.o.) was administered once daily for four weeks, starting one week after ovariectomy. The serum bone turnover marker and cytokine levels, bone density, mass, mineralization, mechanical properties, histomorphometric parameters of compact and cancellous bone, skeletal muscle mass and grip strength were determined. In NOVX rats, memantine slightly decreased the strength of compact bone of the femoral diaphysis (parameters in the yield point) and unfavorably affected histomorphometric parameters of cancellous bone (the femoral epiphysis and metaphysis). In OVX rats, in which estrogen deficiency induced osteoporotic changes, memantine increased the phosphorus content in the femoral bone mineral. No other effects on bone were observed in the memantine-treated OVX rats. In conclusion, the results of the present study indicated slight damaging skeletal effects of memantine in rats with normal estrogen levels.

Fountain of youth—Targeting autophagy in aging

As our society ages inexorably, geroscience and research focusing on healthy aging is becoming increasingly urgent. Macroautophagy (referred to as autophagy), a highly conserved process of cellular clearance and rejuvenation has attracted much attention due to its universal role in organismal life and death. Growing evidence points to autophagy process as being one of the key players in the determination of lifespan and health. Autophagy inducing interventions show significant improvement in organismal lifespan demonstrated in several experimental models. In line with this, preclinical models of age-related neurodegenerative diseases demonstrate pathology modulating effect of autophagy induction, implicating its potential to treat such disorders. In humans this specific process seems to be more complex. Recent clinical trials of drugs targeting autophagy point out some beneficial effects for clinical use, although with limited effectiveness, while others fail to show any significant improvement. We propose that using more human-relevant preclinical models for testing drug efficacy would significantly improve clinical trial outcomes. Lastly, the review discusses the available cellular reprogramming techniques used to model neuronal autophagy and neurodegeneration while exploring the existing evidence of autophagy’s role in aging and pathogenesis in human-derived in vitro models such as embryonic stem cells (ESCs), induced pluripotent stem cell derived neurons (iPSC-neurons) or induced neurons (iNs).

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.

Immunization with Neural-Derived Peptides in Neurodegenerative Diseases: A Narrative Review

Neurodegenerative diseases (NDDs) are a major health problem worldwide. Statistics suggest that in America in 2030 there will be more than 12 million people suffering from a neurodegenerative pathology. Furthermore, the increase in life expectancy enhances the importance of finding new and better therapies for these pathologies. NDDs could be classified into chronic or acute, depending on the time required for the development of clinical symptoms and brain degeneration. Nevertheless, both chronic and acute stages share a common immune and inflammatory pathway in their pathophysiology. Immunization with neural-derived peptides (INDP) is a novel therapy that has been studied during the last decade. By inoculating neural-derived peptides obtained from the central nervous system (CNS), this therapy aims to boost protective autoimmunity, an autoreactive response that leads to a protective phenotype that produces a healing environment and neuroregeneration instead of causing damage. INDP has shown promising findings in studies performed either in vitro, in vivo or even in some pre-clinical trials of different NDDs, standing as a potentially beneficial therapy. In this review, we will describe some of the studies in which the effect of INDP strategies have been explored in different (chronic and acute) neurodegenerative diseases.

Adamantanes for the treatment of neurodegenerative diseases in the presence of SARS-CoV-2

Advent of the acute respiratory coronavirus SARS-CoV-2 has resulted in the search for novel antiviral agents and in the repurposing of existing agents with demonstrated efficacy against other known coronaviruses in the search for an agent with antiviral activity for use during the COVID-19 pandemic. Adamantanes including amantadine, rimantadine, and memantine have well-established benefit in the treatment of neurodegenerative diseases including Parkinson's disease (PD), Alzheimer's disease (AD) and fatigue related to Multiple sclerosis (MS) all of which are known comorbidities related to COVID-19 Moreover, results of basic pharmacological studies both in vitro and in vivo reveal that amantadine has the potential to inhibit SARS-CoV-2 via down-regulation of host-cell proteases resulting in impaired viral genome release into the host cell and via amantadine's property as an NMDA receptor antagonist resulting in the prevention of the acute lung injury and respiratory distress that is characteristic of COVID-19. Cases suggestive of COVID-19 prophylaxis have been reported in patients with PD or MS or severe cognitive impairment treated in all cases for several months with an adamantane [amantadine or memantine] who were subsequently infected with SARS-CoV-2 confirmed by RT-PCR, and, in all cases, no signs of infectious disease were encountered. Amantadine is effective for the treatment of fatigue in MS and for the neurological complications of Traumatic Brain Injury (TBI).

Neurotransmitters in Prevention and Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is the most frequent cause of cognitive impairment in middle-aged and older populations. There is a lack of drugs that demonstrate significant efficacy in AD, so the study of the pathogenesis of AD is of great importance. More efficacious interventions are needed, as reflected by our population's fast aging. Synaptic plasticity is the capacity of neurons to adjust their connections, and it is strongly tied to learning and memory, cognitive function, and brain injury recovery. Changes in synaptic strength, such as long-term potentiation (LTP) or inhibition (LTD), are thought to represent the biological foundation of the early stages of learning and memory. The results of numerous studies confirm that neurotransmitters and their receptors play an important role in the regulation of synaptic plasticity. However, so far, there is no definite correlation between the function of neurotransmitters in aberrant neural oscillation and AD-related cognitive impairment. We summarized the AD process to understand the impact of neurotransmitters in the progression and pathogenesis of AD, including the current status of neurotransmitter target drugs, and the latest evidence of neurotransmitters' function and changes in the AD process.

Integrating mechanistic-based and classification-based concepts into perioperative pain management: an educational guide for acute pain physicians

Chronic pain begins with acute pain. Physicians tend to classify pain by duration (acute vs chronic) and mechanism (nociceptive, neuropathic and nociplastic). Although this taxonomy may facilitate diagnosis and documentation, such categories are to some degree arbitrary constructs, with significant overlap in terms of mechanisms and treatments. In clinical practice, there are myriad different definitions for chronic pain and a substantial portion of chronic pain involves mixed phenotypes. Classification of pain based on acuity and mechanisms informs management at all levels and constitutes a critical part of guidelines and treatment for chronic pain care. Yet specialty care is often siloed, with advances in understanding lagging years behind in some areas in which these developments should be at the forefront of clinical practice. For example, in perioperative pain management, enhanced recovery protocols are not standardized and tend to drive treatment without consideration of mechanisms, which in many cases may be incongruent with personalized medicine and mechanism-based treatment. In this educational document, we discuss mechanisms and classification of pain as it pertains to commonly performed surgical procedures. Our goal is to provide a clinical reference for the acute pain physician to facilitate pain management decision-making (both diagnosis and therapy) in the perioperative period.

Memantine as a neuroprotective agent in ischemic stroke: Preclinical and clinical analysis

The primary mechanism for neuron death after an ischemic stroke is excitotoxic injury. Excessive depolarization leads to NMDA-mediated calcium entry to the neuron and, subsequently, cellular death. Therefore, the inhibition of the NMDA channel has been proposed as a neuroprotective measure in ischemic stroke. The high morbimortality associated with stroke warrants new therapies that can improve the functional prognosis of patients. Memantine is a non-competitive NMDA receptor antagonist which has gained attention as a potential drug for ischemic stroke. Here we analyze the available preclinical and clinical evidence concerning the use of memantine following an ischemic stroke. Preclinical evidence shows inhibition of the excitotoxic cascade, as well as improved outcomes in terms of motor and sensory function with the use of memantine. The available clinical trials of high-dose memantine in patients poststroke have found that it can improve patients' NIHSS and Barthel index and help patients with poststroke aphasia and intracranial hemorrhage. These results suggest that memantine has a clinically relevant neuroprotective effect; however, small sample sizes and other study shortcomings limit the impact of these findings. Even so, current studies show promising results that should serve as a basis to promote future research to conclusively determine if memantine does improve the outcomes of patients' post-ischemic stroke. We anticipate that future trials will fill current gaps in knowledge, and these latter results will broaden the therapeutic arsenal for clinicians looking to improve the prognosis of patients poststroke.

Preliminary Evidence that Memantine Enhances Prepulse Effects on Startle Magnitude and Latency in Patients with Alzheimer's Disease

BACKGROUND

The uncompetitive NMDA antagonist, memantine (MEM), enhances prepulse inhibition of startle (PPI) across species. MEM is used to treat Alzheimer's disease (AD); conceivably, its acute impact on PPI might be used to predict a patient's sensitivity to MEM's therapeutic effects.

OBJECTIVE

To begin to test this possibility, we studied MEM effects on PPI and related measures in AD patients.

METHODS

18 carefully screened individuals with AD (mean age = 72.8 y; M:F=9 : 9) completed double-blind order-balanced testing with MEM (placebo versus 20 mg), assessing acoustic startle magnitude, habituation, PPI, and latency.

RESULTS

Fifteen out of 18 participants exhibited reliable startle responses. MEM did not significantly impact startle magnitude or habituation. Compared to placebo responses, PPI was significantly increased after MEM (p < 0.04; d = 0.40); this comparison reached a large effect size for the 60 ms interval (d = 0.62), where maximal MEM effects on PPI were previously detected. Prepulses reduced peak startle latency ("latency facilitation") and this effect was amplified after MEM (p = 0.03; d = 0.41; for 60 ms intervals, d = 0.69). No effects of MEM were detected on cognition, nor were MEM effects on startle associated with cognitive or clinical measures.

CONCLUSION

MEM enhances prepulse effects on startle magnitude and latency in AD; these changes in PPI and latency facilitation with MEM suggest that these measures can be used to detect an AD patient's neural sensitivity to acute MEM challenge. Studies in progress will determine whether such a "biomarker" measured at the outset on treatment can predict sensitivity to MEM's therapeutic effects.

Targeting immunoproteasome in neurodegeneration: A glance to the future

The immunoproteasome is a specialized form of proteasome equipped with modified catalytic subunits that was initially discovered to play a pivotal role in MHC class I antigen processing and immune system modulation. However, over the last years, this proteolytic complex has been uncovered to serve additional functions unrelated to antigen presentation. Accordingly, it has been proposed that immunoproteasome synergizes with canonical proteasome in different cell types of the nervous system, regulating neurotransmission, metabolic pathways and adaptation of the cells to redox or inflammatory insults. Hence, studying the alterations of immunoproteasome expression and activity is gaining research interest to define the dynamics of neuroinflammation as well as the early and late molecular events that are likely involved in the pathogenesis of a variety of neurological disorders. Furthermore, these novel functions foster the perspective of immunoproteasome as a potential therapeutic target for neurodegeneration. In this review, we provide a brain and retina-wide overview, trying to correlate present knowledge on structure-function relationships of immunoproteasome with the variety of observed neuro-modulatory functions.

APC/C-Cdh1-targeted substrates as potential therapies for Alzheimer's disease

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder and the main cause of dementia in the elderly. The disease has a high impact on individuals and their families and represents a growing public health and socio-economic burden. Despite this, there is no effective treatment options to cure or modify the disease progression, highlighting the need to identify new therapeutic targets. Synapse dysfunction and loss are early pathological features of Alzheimer's disease, correlate with cognitive decline and proceed with neuronal death. In the last years, the E3 ubiquitin ligase anaphase promoting complex/cyclosome (APC/C) has emerged as a key regulator of synaptic plasticity and neuronal survival. To this end, the ligase binds Cdh1, its main activator in the brain. However, inactivation of the anaphase promoting complex/cyclosome-Cdh1 complex triggers dendrite disruption, synapse loss and neurodegeneration, leading to memory and learning impairment. Interestingly, oligomerized amyloid-β (Aβ) peptide, which is involved in Alzheimer's disease onset and progression, induces Cdh1 phosphorylation leading to anaphase promoting complex/cyclosome-Cdh1 complex disassembly and inactivation. This causes the aberrant accumulation of several anaphase promoting complex/cyclosome-Cdh1 targets in the damaged areas of Alzheimer's disease brains, including Rock2 and Cyclin B1. Here we review the function of anaphase promoting complex/cyclosome-Cdh1 dysregulation in the pathogenesis of Alzheimer's disease, paying particular attention in the neurotoxicity induced by its molecular targets. Understanding the role of anaphase promoting complex/cyclosome-Cdh1-targeted substrates in Alzheimer's disease may be useful in the development of new effective disease-modifying treatments for this neurological disorder.

Reaction of 7α-bromo-6-nitrocholest-5-enes with hydrazine: Formation of steroidal pyrazolines and molecular docking against SARS-CoV-2 omicron protease

The present work reports simple and effective protocol for preparing 6α-nitro-5α-cholestano[7α,5-cd] pyrazolines (4-7) by the reaction of 7α-bromo-6-nitrocholest-5-enes (1-3) with hydrazine hydrate under reflux [the substrate (2) gave products (5) and (6) and the later on acetylation with AC₂O/Py gave (7)]. In the case of reaction of 3β-hydroxy analogue (3) with hydrazine, however, 6α-nitro-5α-cholestano [3α,5-cd] pyrazoline (8) and 6α-nitro-3β, 5-oxido-5β-cholestane (9) were obtained. The probable mechanism of the formation of pyrazolines has also been outlined. In the current pandemic coronavirus disease 2019 scenario, the in-silico study was performed with reactants (1-3), their products (4-9) against SARS-CoV-2 omicron protease (PDB ID:7T9L) for knowing significant interactions between them. Docking results give information that both reactants and products have binding energies ranges from -5.7 to 7.7 kcal/mol and strong interactions with various hydrophilic and hydrophobic amino acids such as ASP, PRO, PHE, SER and LEU which are significant residues playing important role in SARS-CoV-2 Omicron main protease (Mpro).

Benefit and safety of antibiotics for Alzheimer's disease: Protocol for a systematic review and meta-analysis

BACKGROUND

Alzheimer's disease (AD) is an age-related degenerative change of the central nervous system, the cause of which remains unclear. Recent studies have found that brain inflammation caused by microbial infections may be one of the etiologies of AD, and antibiotics as novel treatments may be beneficial for delaying the development of AD. Several prospective studies have investigated the effects of different antibiotics on Alzheimer's disease. However, no systematic review or meta-analysis has evaluated the benefits and safety of antibiotics in AD patients.

METHODS

This study will analyze randomized controlled trials and observational studies published from database inception to December 31, 2022, and included direct or indirect evidence. Studies will be retrieved by searching PubMed, Scopus, Web of Science, Cochrane Central Register of Controlled Clinical Trials, CNKI, and Wan Fang databases. The outcomes of this study included the Alzheimer's Disease Assessment Scale cognitive subscale (ADAS-cog), Montreal Cognitive Assessment (MoCA), Standardized Mini-Mental State Examination (SMMSE), Clinical Dementia Rating (CDR), Frontal Functioning Scale (FAB), Dysfunctional Behavior Rating Instrument (DBRI), Activities of Daily Living (ADLs) Index, and Geriatric Depression Scale (GDS). The risk of bias will be assessed using the Cochrane risk-of-bias assessment instrument for randomized controlled trials. A random-effect/fixed-effects model will be used to summarize the estimates of the mean difference/risk ratio using a 95% confidence interval.

RESULTS

This study will analyze the benefits and safety of antibiotics in patients with AD.

CONCLUSION

The results of this analysis will provide evidence to evaluate the benefits and safety of antibiotics in the treatment of AD.

The effects of the ethanol extract of Cordia myxa leaves on the cognitive function in mice

Background

Cordia myxa L. (Boraginaceae) is widely distributed in tropical regions and it’s fruits, leaves and stem bark have been utilized in folk medicine for treating trypanosomiasis caused by Trypanosoma cruzi. A population-based study showed that T. cruzi infection is associated with cognitive impairments. Therefore, if C. myxa has ameliorating activities on cognitive function, it would be useful for both T. cruzi infection and cognitive impairments.

Methods

In this study, we evaluated the effects of an ethanol extract of leaves of C. myxa (ELCM) on memory impairments and sensorimotor gating deficits in mice. The phosphorylation level of protein was observed by the Western blot analysis.

Results

The administration of ELCM significantly attenuated scopolamine-induced cognitive dysfunction in mice, as measured by passive avoidance test and novel object recognition test. Additionally, in the acoustic startle response test, we observed that the administration of ELCM ameliorated MK-801-induced prepulse inhibition deficits. We found that these behavioral outcomes were related with increased levels of phosphorylation phosphatidylinositol 3-kinase (PI3K), protein kinase B (Akt) and glycogen synthase kinase 3 beta (GSK-3β) in the cortex and extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB) in the hippocampus by western blot analysis.

Conclusions

These results suggest that ELCM would be a potential candidate for treating cognitive dysfunction and sensorimotor gating deficits observed in individuals with neurodegenerative diseases.

New Possibilities in the Therapeutic Approach to Alzheimer’s Disease

Despite the fact that Alzheimer’s disease (AD) is the most common cause of dementia, after many years of research regarding this disease, there is no casual treatment. Regardless of the serious public health threat it poses, only five medical treatments for Alzheimer’s disease have been authorized, and they only control symptoms rather than changing the course of the disease. Numerous clinical trials of single-agent therapy did not slow the development of disease or improve symptoms when compared to placebo. Evidence indicates that the pathological alterations linked to AD start many years earlier than a manifestation of the disease. In this pre-clinical period before the neurodegenerative process is established, pharmaceutical therapy might prove invaluable. Although recent findings from the testing of drugs such as aducanumab are encouraging, they should nevertheless be interpreted cautiously. Such medications may be able to delay the onset of dementia, significantly lowering the prevalence of the disease, but are still a long way from having a clinically effective disease-modifying therapy.

Ten-Year Trends in Sales of Alzheimer Disease Drugs in France Compared With Sales in Germany, Spain, and the UK

This cross-sectional study analyzes 10-year trends in sales of Alzheimer disease drugs in France compared with trends in the UK, Spain, and Germany.

Pharmacotherapy of Alzheimer's disease: an overview of systematic reviews

BACKGROUND

Alzheimer's disease (AD) is a neurodegenerative disease and the most common cause of dementia. In this umbrella systematic review (SR), we summarized the efficacy of different pharmacological interventions in improving cognitive function in patients with AD.

METHODS

A systematic search was performed through the PubMed, Scopus, Embase, and Cochrane databases for SRs of studies assessing the efficacy of pharmacological interventions versus placebo in improving cognitive function in AD or mild cognitive impairment due to AD. The risk of bias (RoB) was assessed using the Risk of Bias in SRs (ROBIS) tool.

RESULTS

Out of 1748 articles found through the database survey, 33 SR articles were included. These studies assessed effects of immunotherapy, cholinesterase inhibitors (ChEIs), memantine, statins, lithium, nonsteroidal anti-inflammatory drugs (NSAIDs), antidiabetic agents, Cerebrolysin, RAS-targeting antihypertensive drugs (ARBs and ACEIs), psychostimulants, glycogen synthase kinase 3 (GSK-3) inhibitors, melatonin, and herbal medications on cognitive function in AD patients. There was no notable overall RoB in 18 studies (54.5%), the RoB in 14 studies (42.4%) was high, and in one study (3.0%) it was unclear.

CONCLUSIONS

The use of ChEIs, including rivastigmine, galantamine, and donepezil, as well as memantine has demonstrated a positive impact on improving cognitive outcomes of AD patients, but no considerable effects were found for immunotherapies. Melatonin, statins, antihypertensive drugs, antidiabetic agents, Cerebrolysin, psychostimulants, and some herbal drugs such as Danggui-Shaoyao-San and Ginkgo biloba seem to be effective in improving cognitive function of AD patients, but the evidence in this regard is limited.

Synaptic Secretion and Beyond: Targeting Synapse and Neurotransmitters to Treat Neurodegenerative Diseases

The nervous system is important, because it regulates the physiological function of the body. Neurons are the most basic structural and functional unit of the nervous system. The synapse is an asymmetric structure that is important for neuronal function. The chemical transmission mode of the synapse is realized through neurotransmitters and electrical processes. Based on vesicle transport, the abnormal information transmission process in the synapse can lead to a series of neurorelated diseases. Numerous proteins and complexes that regulate the process of vesicle transport, such as SNARE proteins, Munc18-1, and Synaptotagmin-1, have been identified. Their regulation of synaptic vesicle secretion is complicated and delicate, and their defects can lead to a series of neurodegenerative diseases. This review will discuss the structure and functions of vesicle-based synapses and their roles in neurons. Furthermore, we will analyze neurotransmitter and synaptic functions in neurodegenerative diseases and discuss the potential of using related drugs in their treatment.

Resveratrol ameliorates learning and memory impairments induced by bilateral hippocampal injection of streptozotocin in mice

Resveratrol (RES) is a polyphenol with diverse beneficial pharmacological activities, and our previous results have demonstrated its neuroprotective potential. The purpose of this study was to investigate the therapeutic effect of RES in Alzheimer's disease (AD)-like behavioral dysfunction induced by streptozotocin (STZ) and explore it's potential mechanism of action. STZ was microinjected bilaterally into the dorsal hippocampus of C57BL/6J mice at a dose of 3 mg/kg, and RES was administered intragastrically at a dose of 25 mg/kg for 5 weeks. Neurobehavioral performance was observed, and serum concentrations of insulin and Nesfatin-1 were measured. Moreover, the protein expression of amyloid beta 1-42 (Aβ_1-42), Tau, phosphorylated Tau (p-Tau) (Ser396), synaptic ras GTPase activation protein (SynGAP), postsynaptic density protein 95 (PSD95), synapsin-1, synaptogomin-1, and key molecules of the Wnt/β-catenin signaling pathway in the hippocampus and prefrontal cortex (PFC) were assessed. Finally, pathological damage to hippocampal tissue was examined by Nissl and immunofluorescence staining. The results showed that compared with the controls, bilateral hippocampal microinjections of STZ induced task-specific learning and memory impairments, as indicated by the disadvantaged performances in the novel object recognition test (NOR) and Morris water maze (MWM), but not the contextual fear conditioning test (CFC). Treatment with RES could improve these behavioral disadvantages. The serum concentrations of insulin and Nesfatin-1 in the model group were remarkably higher than those of the control group. In addition, protein expression of Aβ_1-42, Tau, and p-Tau (Ser396) was increased but expression of SynGAP, PSD95, brain-derived neurotrophic factor (BDNF), and p-GSK-3β/GSK-3β were decreased in the hippocampus. Although the protein expression of BDNF and SynGAP was also markedly decreased in the PFC of the model mice, there was no significant difference among groups in the protein expression of PSD95, BDNF, synapsin-1, synaptogomin-1, and p-GSK-3β/GSK-3β. RES (25 mg/kg) reversed the enhanced insulin level, the abnormal protein expression of Aβ_1-42, Tau, and p-Tau (Ser396) in the hippocampus and PFC, and the hippocampal protein expression of SynGAP, PSD95 and BDNF. In addition, RES reversed the STZ-induced decrease in the number of Nissl bodies and the increase in fluorescence intensity of IBA1 in the hippocampal CA1 region. These findings indicate that RES could ameliorate STZ-induced AD-like neuropathological injuries, the mechanism of which could be partly related to its regulation of BDNF expression and synaptic plasticity-associated proteins in the hippocampus.

NMDA receptor antagonists reduce amyloid-β deposition by modulating calpain-1 signaling and autophagy, rescuing cognitive impairment in 5XFAD mice

Overstimulation of N-methyl-d-aspartate receptors (NMDARs) is the leading cause of brain excitotoxicity and often contributes to neurodegenerative diseases such as Alzheimer’s Disease (AD), the most common form of dementia. This study aimed to evaluate a new NMDA receptor antagonist (UB-ALT-EV) and memantine in 6-month-old female 5XFAD mice that were exposed orally to a chronic low-dose treatment. Behavioral and cognitive tests confirmed better cognitive performance in both treated groups. Calcium-dependent protein calpain-1 reduction was found after UB-ALT-EV treatment but not after memantine. Changes in spectrin breakdown products (SBDP) and the p25/p35 ratio confirmed diminished calpain-1 activity. Amyloid β (Aβ) production and deposition was evaluated in 5XFAD mice and demonstrated a robust effect of NMDAR antagonists on reducing Aβ deposition and the number and size of Thioflavin-S positive plaques. Furthermore, glycogen synthase kinase 3β (GSK3β) active form and phosphorylated tau (AT8) levels were diminished after UB-ALT-EV treatment, revealing tau pathology improvement. Because calpain-1 is involved in autophagy activation, autophagic proteins were studied. Strikingly, results showed changes in the protein levels of unc-51-like kinase (ULK-1), beclin-1, microtubule-associated protein 1A/1B-light chain 3(LC3B-II)/LC3B-I ratio, and lysosomal-associated membrane protein 1 (LAMP-1) after NMDAR antagonist treatments, suggesting an accumulation of autophagolysosomes in 5XFAD mice, reversed by UB-ALT-EV. Likewise, treatment with UB-ALT-EV recovered a WT mice profile in apoptosis markers Bcl-2, Bax, and caspase-3. In conclusion, our results revealed the potential neuroprotective effect of UB-ALT-EV by attenuating NMDA-mediated apoptosis and reducing Aβ deposition and deposition jointly with the autophagy rescue to finally reduce cognitive alterations in a mice model of familial AD.

The efficacy and tolerability of memantine for depressive symptoms in major mental diseases: A systematic review and updated meta-analysis of double-blind randomized controlled trials

OBJECTIVE

To date, there is limited evidence on the antidepressant effects of memantine in patients with major mental diseases. We conducted a systematic review and meta-analysis to assess the efficacy of memantine in such populations.

METHODS

A literature search was performed for randomized controlled trials (RCTs) from the date of their inception until September 28, 2021, using PubMed, Medline, Embase, and the Cochrane Library. Changes in depression scores were the primary outcome. The response rate and remission rate to the treatment were secondary outcomes. We also assessed the dropout rate for tolerance.

RESULTS

Eleven double-blind RCTs were included with 899 participants. Memantine significantly reduced depressive symptom scores compared with the control group (k = 11, n = 899, Hedges' g = -0.17, 95% confidence interval [CI] = -0.30 to -0.04, p = 0.009) with a small effect size. For secondary outcomes, memantine did not show a significant effect on response rate nor remission rate. In the subgroup analysis, memantine significantly reduced depressive symptom scores in patients with mood disorders (k = 8, n = 673, Hedges' g = -0.17, 95% CI = -0.32 to -0.01, p = 0.035) with a small effect size, but not in patients with schizophrenia.

CONCLUSION

The present meta-analysis indicates that memantine effectively alleviates depressive symptoms in patients with mood disorders with a small effect size. Furthermore, memantine is well-tolerated and acceptable.

Pharmacological Approaches to the Treatment of Dementia in Down Syndrome: A Systematic Review of Randomized Clinical Studies

Down Syndrome (DS) is considered the most frequent form of Intellectual Disability, with important expressions of cognitive decline and early dementia. Studies on potential treatments for dementia in this population are still scarce. Thus, the current review aims to synthesize the different pharmacological approaches that already exist in the literature, which focus on improving the set of symptoms related to dementia in people with DS. A total of six studies were included, evaluating the application of supplemental antioxidant therapies, such as alpha-tocopherol; the use of acetylcholinesterase inhibitor drugs, such as donepezil; N-methyl-d-aspartate (NMDA) receptor antagonists, such as memantine; and the use of vitamin E and a fast-acting intranasal insulin. Two studies observed important positive changes related to some general functions in people with DS (referring to donepezil). In the majority of studies, the use of pharmacological therapies did not lead to improvement in the set of symptoms related to dementia, such as memory and general functionality, in the population with DS.

[Comparative clinical study of the pharmacokinetics and bioequivalence of the combined drug Mioreol and the combined use of mono-drugs containing donepezil and memantine]

OBJECTIVE

The study of bioequivalence and safety of the fixed combination of the drug Mioreol (Donepezil + Memantine, 10 mg + 20 mg) in relation to the combined use of Yasnal 10 mg and Akatinol Memantin 20 mg.

MATERIAL AND METHODS

The safety analysis study included 36 male (n=8) and female (n=10) subjects, sexes (age 26.3±7.1 years, body mass index (BMI) 23.0±2.8 kg/m²). In the study for the analysis of pharmacokinetics - 31 male (n=8) and female (n=10) persons (age 26.5±7.9 years, BMI 23.5±3.1 kg/m²). The method used high performance liquid chromatography with tandem mass spectrometric detection. Pharmacokinetic analysis was carried out using Phoenix WinNonlin software («CERTARA», Pharsight, USA) v. 8.2. Statistical analysis of the obtained data was performed based on the assumption of a lognormal distribution of parameters AUC_0-72 and C_max.

RESULTS

Geometric mean ratio for key pharmacokinetic parameters (AUC_0-t, AUC_0-####sub/sub#### and C_max) donepezil and memantine are close to 100% and 90%, measuring ranges are within acceptable limits for bioequivalent drugs range (80-125%) for both active ingredients. Within-subject variability (CVintra) for donepezil was 9.34% (C_max), 6.12% (AUC_0-t), and for memantine - 8.13% (C_max), 6.67% (AUC_0-t).

The average profiles of the pharmacokinetic curves of donepezil and memantine when taking the test drug and the combination of comparator drugs have similar forms. Fixed combination Mioreol (Donepezil + Memantine, drug, 10 mg + 20 mg) and Yasnal preparations 10 mg (Krka JSC, d.d., Novo Mesto) and Akatinol Memantine 20 mg («Merz Pharma GmbH and Co. KGaA», Germany) when taken together are bioequivalent.

CONCLUSION

The results of the study allow us to recommend Mioreol for further clinical study and wide practical application.

Design, synthesis, and in vitro and in vivo characterization of new memantine analogs for Alzheimer's disease

Currently, of the few accessible symptomatic therapies for Alzheimer's disease (AD), memantine is the only N-methyl-d-aspartate receptor (NMDAR) blocker approved by the FDA. This work further explores a series of memantine analogs featuring a benzohomoadamantane scaffold. Most of the newly synthesized compounds block NMDARs in the micromolar range, but with lower potency than previously reported hit IIc, results that were supported by molecular dynamics simulations. Subsequently, electrophysiological studies with the more potent compounds allowed classification of IIc, a low micromolar, uncompetitive, voltage-dependent, NMDAR blocker, as a memantine-like compound. The excellent in vitro DMPK properties of IIc made it a promising candidate for in vivo studies in Caenorhabditis elegans (C. elegans) and in the 5XFAD mouse model of AD. Administration of IIc or memantine improved locomotion and rescues chemotaxis behavior in C. elegans. Furthermore, both compounds enhanced working memory in 5XFAD mice and modified NMDAR and CREB signaling, which may prevent synaptic dysfunction and modulate neurodegenerative progression.