Comparative Effectiveness and Safety of Cognitive Enhancers for Treating Alzheimer's Disease: Systematic Review and Network Metaanalysis

Alzheimer's Amyloid Hypothesis and Antibody Therapy: Melting Glaciers?

The amyloid cascade hypothesis for Alzheimer's disease is still alive, although heavily challenged. Effective anti-amyloid immunotherapy would confirm the hypothesis' claim that the protein amyloid-beta is the cause of the disease. Two antibodies, aducanumab and lecanemab, have been approved by the U.S. Food and Drug Administration, while a third, donanemab, is under review. The main argument for the FDA approvals is a presumed therapy-induced removal of cerebral amyloid deposits. Lecanemab and donanemab are also thought to cause some statistical delay in the determination of cognitive decline. However, clinical efficacy that is less than with conventional treatment, selection of amyloid-positive trial patients with non-specific amyloid-PET imaging, and uncertain therapy-induced removal of cerebral amyloids in clinical trials cast doubt on this anti-Alzheimer's antibody therapy and hence on the amyloid hypothesis, calling for a more thorough investigation of the negative impact of this type of therapy on the brain.

Patterns of use of symptomatic treatments for Alzheimer's disease dementia (AD)

BACKGROUND

Symptomatic treatment for Alzheimer's disease (AD) dementia could temporarily slow symptom worsening and improve the quality of life for both AD dementia patients and their caregivers. A comprehensive evaluation of symptomatic treatment patterns using recent data for newly diagnosed AD dementia has not been performed and compared across different countries.

METHODS

The drug name, time to the first therapy, duration, discontinuation or switches were described in newly diagnosed AD dementia patients in two databases (a major U.S. health plan [US] and UK-Clinical Practice Research Datalink [CPRD GOLD]). This analysis included patients with newly diagnosed AD dementia in 2018-2019, who initiated symptomatic AD drug therapy, with ≥ 1 year baseline period and ≥ 1 year of follow-up.

RESULTS

Over median follow-ups of 698 and 645 days, 63% and 65% of AD dementia patients used symptomatic treatments, with 34% and 77% newly initiating therapy, constituting analytic samples of 7637 patients in the US database and 4470 patients in the CPRD, respectively. The median time to the first therapy was 14 days for US and 49 days for CPRD; donepezil ranked the as most frequently used (69% vs 61%), followed by memantine (19% vs 28%) in the US database and CPRD, respectively. Median time on first therapy was 213 and 334 days, and 30% and 12% of patients proceeded to a second treatment in the US and CPRD databases, respectively.

CONCLUSION

Approximately two thirds of newly diagnosed AD dementia patients utilized approved symptomatic treatment. Time on first therapy was relatively short (< 1 year) and the majority did not move to a second therapy, highlighting the need for better adherence and persistence to existing AD symptomatic therapies and the need for additional therapies to alleviate the significant burden of AD dementia.

Psychiatric Adverse Events of Acetylcholinesterase Inhibitors in Alzheimer's Disease and Parkinson's Dementia: Systematic Review and Meta-Analysis

BACKGROUND

The acetylcholinesterase inhibitors (AChEIs) donepezil, galantamine, and rivastigmine are commonly used in the management of various forms of dementia.

OBJECTIVES

While these drugs are known to induce classic cholinergic adverse events such as diarrhea, their potential to cause psychiatric adverse events has yet to be thoroughly examined.

METHODS

We sought to determine the risk of psychiatric adverse events associated with the use of AChEIs through a systematic review and meta-analysis of double-blind randomized controlled trials involving patients with Alzheimer's dementia and Parkinson's dementia.

RESULTS

A total of 48 trials encompassing 22,845 patients were included in our analysis. Anorexia was the most commonly reported psychiatric adverse event, followed by agitation, insomnia, and depression. Individuals exposed to AChEIs had a greater risk of experiencing appetite disorders, insomnia, or depression compared with those who received placebo (anorexia: odds ratio [OR] 2.93, 95% confidence interval [CI] 2.29-3.75; p < 0.00001; decreased appetite: OR 1.93, 95% CI 1.33-2.82; p = 0.0006; insomnia: OR 1.55, 95% CI 1.25-1.93; p < 0.0001; and depression: OR 1.59, 95% CI 1.23-2.06, p = 0.0004). Appetite disorders were also more frequent with high-dose versus low-dose therapy. A subgroup analysis revealed that the risk of insomnia was higher for donepezil than for galantamine.

CONCLUSIONS

Our findings suggest that AChEI therapy may negatively impact psychological health, and careful monitoring of new psychiatric symptoms is warranted. Lowering the dose may resolve some psychiatric adverse events, as may switching to galantamine in the case of insomnia.

CLINICAL TRIAL REGISTRATION

The study was pre-registered on PROSPERO (CRD42021258376).

Extrasynaptic NMDA receptors in acute and chronic excitotoxicity: implications for preventive treatments of ischemic stroke and late-onset Alzheimer's disease

Stroke and late-onset Alzheimer's disease (AD) are risk factors for each other; the comorbidity of these brain disorders in aging individuals represents a significant challenge in basic research and clinical practice. The similarities and differences between stroke and AD in terms of pathogenesis and pathophysiology, however, have rarely been comparably reviewed. Here, we discuss the research background and recent progresses that are important and informative for the comorbidity of stroke and late-onset AD and related dementia (ADRD). Glutamatergic NMDA receptor (NMDAR) activity and NMDAR-mediated Ca²⁺ influx are essential for neuronal function and cell survival. An ischemic insult, however, can cause rapid increases in glutamate concentration and excessive activation of NMDARs, leading to swift Ca²⁺ overload in neuronal cells and acute excitotoxicity within hours and days. On the other hand, mild upregulation of NMDAR activity, commonly seen in AD animal models and patients, is not immediately cytotoxic. Sustained NMDAR hyperactivity and Ca²⁺ dysregulation lasting from months to years, nevertheless, can be pathogenic for slowly evolving events, i.e. degenerative excitotoxicity, in the development of AD/ADRD. Specifically, Ca²⁺ influx mediated by extrasynaptic NMDARs (eNMDARs) and a downstream pathway mediated by transient receptor potential cation channel subfamily M member (TRPM) are primarily responsible for excitotoxicity. On the other hand, the NMDAR subunit GluN3A plays a "gatekeeper" role in NMDAR activity and a neuroprotective role against both acute and chronic excitotoxicity. Thus, ischemic stroke and AD share an NMDAR- and Ca²⁺-mediated pathogenic mechanism that provides a common receptor target for preventive and possibly disease-modifying therapies. Memantine (MEM) preferentially blocks eNMDARs and was approved by the Federal Drug Administration (FDA) for symptomatic treatment of moderate-to-severe AD with variable efficacy. According to the pathogenic role of eNMDARs, it is conceivable that MEM and other eNMDAR antagonists should be administered much earlier, preferably during the presymptomatic phases of AD/ADRD. This anti-AD treatment could simultaneously serve as a preconditioning strategy against stroke that attacks ≥ 50% of AD patients. Future research on the regulation of NMDARs, enduring control of eNMDARs, Ca²⁺ homeostasis, and downstream events will provide a promising opportunity to understand and treat the comorbidity of AD/ADRD and stroke.

Mapping new pharmacological interventions for cognitive function in Alzheimer's disease: a systematic review of randomized clinical trials

Background and Objective: Alzheimer's disease (AD) is a progressive neurodegenerative disorder, that is, characterized by cognitive decline. To date, there are no effective treatments for AD. Therefore, the objective of this study was to map new perspectives on the effects of pharmacological treatment on cognitive function and the overall psychological state in patients with AD. Methods: Two independent researchers searched for randomized clinical trials (RCTs) exploring new pharmacological approaches related to cognition in Alzheimer's disease in adults from 2018 to 2023 in PubMed, Web of Science, Scopus, and Cochrane Library databases. A total of 17 RCTs were included in this review. Results: The results show that in recent years, new drugs have been tested in patients with Alzheimer's disease, including masitinib, methylphenidate, levetiracetam, Jiannao Yizhi, and Huannao Yicong formulas. Most studies have been conducted in populations with mild to moderate Alzheimer's disease. Conclusion: Although some of the drugs found suggested improvement in cognitive function, the scarcity of available studies highlights the need for further research in this area. Systematic review registration: [www.crd.york.ac.uk/prospero], identifier [CRD42023409986].

Rivastigmine-Benzimidazole Hybrids as Promising Multitarget Metal-Modulating Compounds for Potential Treatment of Neurodegenerative Diseases

With the goal of combating the multi-faceted Alzheimer's disease (AD), a series of Rivastigmine-Benzimidazole (RIV-BIM) hybrids was recently reported by us as multitarget-directed ligands, thanks to their capacity to tackle important hallmarks of AD. In particular, they exhibited antioxidant activity, acted as cholinesterase inhibitors, and inhibited amyloid-β (Aβ) aggregation. Herein, we moved forward in this project, studying their ability to chelate redox-active biometal ions, Cu(II) and Fe(III), with widely recognized roles in the generation of oxidative reactive species and in protein misfolding and aggregation in both AD and Parkinson's disease (PD). Although Cu(II) chelation showed higher efficiency for the positional isomers of series 5 than those of series 4 of the hybrids, the Aβ-aggregation inhibition appears more dependent on their capacity for fibril intercalation than on copper chelation. Since monoamine oxidases (MAOs) are also important targets for the treatment of AD and PD, the capacity of these hybrids to inhibit MAO-A and MAO-B was evaluated, and they showed higher activity and selectivity for MAO-A. The rationalization of the experimental evaluations (metal chelation and MAO inhibition) was supported by computational molecular modeling studies. Finally, some compounds showed also neuroprotective effects in human neuroblastoma (SH-SY5Y cells) upon treatment with 1-methyl-4-phenylpyridinium (MPP⁺), a neurotoxic metabolite of a Parkinsonian-inducing agent.

Recent Development in the Understanding of Molecular and Cellular Mechanisms Underlying the Etiopathogenesis of Alzheimer's Disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that leads to dementia and patient death. AD is characterized by intracellular neurofibrillary tangles, extracellular amyloid beta (Aβ) plaque deposition, and neurodegeneration. Diverse alterations have been associated with AD progression, including genetic mutations, neuroinflammation, blood-brain barrier (BBB) impairment, mitochondrial dysfunction, oxidative stress, and metal ion imbalance.Additionally, recent studies have shown an association between altered heme metabolism and AD. Unfortunately, decades of research and drug development have not produced any effective treatments for AD. Therefore, understanding the cellular and molecular mechanisms underlying AD pathology and identifying potential therapeutic targets are crucial for AD drug development. This review discusses the most common alterations associated with AD and promising therapeutic targets for AD drug discovery. Furthermore, it highlights the role of heme in AD development and summarizes mathematical models of AD, including a stochastic mathematical model of AD and mathematical models of the effect of Aβ on AD. We also summarize the potential treatment strategies that these models can offer in clinical trials.

Discovering Hair Biomarkers of Alzheimer's Disease Using High Resolution Mass Spectrometry-Based Untargeted Metabolomics

Hair may be a potential biospecimen to discover biomarkers for Alzheimer's disease (AD) since it reflects the integral metabolic profiles of body burden over several months. Here, we described the AD biomarker discovery in the hair using a high-resolution mass spectrometry (HRMS)-based untargeted metabolomics approach. A total of 24 patients with AD and 24 age- and sex-matched cognitively healthy controls were recruited. The hair samples were collected 0.1-cm away from the scalp and further cut into 3-cm segments. Hair metabolites were extracted by ultrasonication with methanol/phosphate-buffered saline 50/50 (v/v) for 4 h. A total of 25 discriminatory chemicals in hair between the patients with AD and controls were discovered and identified. The AUC value achieved 0.85 (95% CI: 0.72~0.97) in patients with very mild AD compared to healthy controls using a composite panel of the 9 biomarker candidates, indicating high potential for the initiation or promotion phase of AD dementia in the early stage. A metabolic panel combined with the nine metabolites may be used as biomarkers for the early detection of AD. The hair metabolome can be used to reveal metabolic perturbations for biomarker discovery. Investigating perturbations of the metabolites will offer insight into the pathogenesis of AD.

Cardiac monitoring in memory clinics: national survey of UK practice

AIMS AND METHOD

People diagnosed with dementia are often started on acetylcholinesterase inhibitors (AChEIs). As AChEIs can be associated with cardiac side-effects, an electrocardiogram (ECG) is sometimes requested before treatment. Previous work has suggested there is little consensus as to when or how ECGs should be obtained. This can create inconsistent practice, with patient safety, economic and practical repercussions. We surveyed 305 UK memory clinic practitioners about prescribing practice.

RESULTS

More than 84% of respondents completed a pulse and cardiac history before prescribing AChEIs. Opinion was divided as to who should fund and conduct ECGs. It was believed that obtaining an ECG causes patients inconvenience and delays treatment. Despite regularly interpreting ECGs, 76% of respondents did not update this clinical skill regularly.

CLINICAL IMPLICATIONS

The variation in practice observed has service-level and patient implications and raises potential patient safety concerns. Implementing national guidelines or seeking novel ways of conducting cardiac monitoring could help standardise practice.

Determinants of approved acetylcholinesterase inhibitor response outcomes in Alzheimer's disease: relevance for precision medicine in neurodegenerative diseases

Acetylcholinesterase inhibitors (ChEI) are the global standard of care for the symptomatic treatment of Alzheimer's disease (AD) and show significant positive effects in neurodegenerative diseases with cognitive and behavioral symptoms. Although experimental and large-scale clinical evidence indicates the potential long-term efficacy of ChEI, primary outcomes are generally heterogeneous across outpatient clinics and regional healthcare systems. Sub-optimal dosing or slow tapering, heterogeneous guidelines about the timing for therapy initiation (prodromal versus dementia stages), healthcare providers' ambivalence to treatment, lack of disease awareness, delayed medical consultation, prescription of ChEI in non-AD cognitive disorders, contribute to the negative outcomes. We present an evidence-based overview of determinants, spanning genetic, molecular, and large-scale networks, involved in the response to ChEI in patients with AD and other neurodegenerative diseases. A comprehensive understanding of cerebral and retinal cholinergic system dysfunctions along with ChEI response predictors in AD is crucial since disease-modifying therapies will frequently be prescribed in combination with ChEI. Therapeutic algorithms tailored to genetic, biological, clinical (endo)phenotypes, and disease stages will help leverage inter-drug synergy and attain optimal combined response outcomes, in line with the precision medicine model.

Efficacy of pharmacotherapy and non-pharmacotherapy of Alzheimer dementia: A protocol for systematic review and meta-analysis

BACKGROUND

Alzheimer disease (AD) is the most common cause of dementia worldwide. Despite the publication of numerous systematic reviews and meta-analyses that have summarized the evidence associated with pharmacotherapies (PTs) and non-pharmacotherapies (NPTs) for the wide range of interventions available for AD treatment, their comparative safety and efficacy remains insufficiently defined.

METHODS

Systematic reviews of randomized controlled trials (RCTs) will be selected according to the following criteria: conducted in elderly patients aged 60 years or older with AD living in community or institutionalized settings, applied pairwise meta-analysis (PMA) or network meta-analysis (NMA) approaches providing pooled relative treatment effects for at least 1 pair of PTs or NPTs, and providing at least 1 of the following outcomes for patients/caregivers: cognitive, functional status, behavior, quality of life (QoL), and caregiver stress or burden. All article screening, data extraction, and risk of bias assessment will be completed independently by 2 reviewers. Relative treatment rankings will be reported with mean ranks and surface under the cumulative ranking curves.

RESULTS AND CONCLUSION

We will determine the most efficacious treatment strategies for AD patients from the most highly ranked treatments. These results will help to guide clinical decision-making and improve patient care.

CBD Oil as a Miracle Drug: A Thematic Analysis of Caregivers’ Attitudes and Practices Towards Cannabidiol in Dementia Treatment

The aim of this study was to understand caregivers of individuals with dementia attitudes toward CBD oil. Thematic analysis was conducted with 67 posts (570 comments) about CBD oil selected from a Polish online support forum for caregivers. We identified caregivers’ expectations, motivations, and practices of using CBD oil. Caregivers expected CBD to improve the behavior, cognition, communication, and daily activities of their loved ones. They motivated each other by sharing experiences about the positive effects of CBD oil and claimed to be administering CBD oil without medical advice, which led to dangerous practices such as an overnight withdrawal of all drugs or experimenting with CBD oil dosage. Caregivers perceive CBD oil as a safer and more effective treatment for those with dementia than the conventional methods. We recommend healthcare professionals inquire about possible CBD oil usage during follow-up visits and thoroughly explain what to expect from prescribed medications.

Multi-Target Mechanisms of Phytochemicals in Alzheimer’s Disease: Effects on Oxidative Stress, Neuroinflammation and Protein Aggregation

Alzheimer’s disease (AD) is a neurodegenerative disease characterized by a tangle-shaped accumulation of beta-amyloid peptide fragments and Tau protein in brain neurons. The pathophysiological mechanism involves the presence of Aβ-amyloid peptide, Tau protein, oxidative stress, and an exacerbated neuro-inflammatory response. This review aims to offer an updated compendium of the most recent and promising advances in AD treatment through the administration of phytochemicals. The literature survey was carried out by electronic search in the following specialized databases PubMed/Medline, Embase, TRIP database, Google Scholar, Wiley, and Web of Science regarding published works that included molecular mechanisms and signaling pathways targeted by phytochemicals in various experimental models of Alzheimer’s disease in vitro and in vivo. The results of the studies showed that the use of phytochemicals against AD has gained relevance due to their antioxidant, anti-neuroinflammatory, anti-amyloid, and anti-hyperphosphorylation properties of Tau protein. Some bioactive compounds from plants have been shown to have the ability to prevent and stop the progression of Alzheimer’s.

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.

Diabetes, Hypertension, and the Risk of Dementia

Background: Type 2 diabetes (T2D) and hypertension (HTN) are well-known modifiable risk factors for dementia, but their intricate attributes accounting for dementia development has not been clearly delineated. Objective: We conducted this study to investigate and compare the effects of T2D and HTN on dementia risk. Methods: We screened data of matched pairs of patients with T2D or HTN between January 1, 2000 and December 31, 2017 from Taiwan’s National Health Insurance Research Database. Fine and Gray’s subdistribution hazard models were used for calculating the risk of dementia. Results: Patients with T2D and subsequent HTN were associated with significantly higher risks of all-cause dementia (aHR 1.51, 95% CI 1.25–1.83) and vascular dementia (aHR 2.30, 95% CI 1.71–3.13) compared with those without subsequent HTN. Patients with HTN and subsequent T2D were associated with significantly higher risks of all-cause dementia (aHR 1.15, 95% CI 1.08–1.21), vascular dementia (aHR 1.25, 95% CI 1.62–1.34), and other dementia (aHR 1.31, 95% CI 1.03–1.66) compared with those without subsequent HTN. The subgroups of male and female patients, age of 50–69 and 70–90 years with subsequent comorbidity were associated with significantly higher risks of all-cause dementia and vascular dementia than those without subsequent comorbidity. Conclusion: This nationwide cohort study demonstrated that patients with T2D and subsequent HTN had association with higher risks of all-cause dementia and vascular dementia, and those with HTN and subsequent T2D were associated with higher risks of all-cause dementia, vascular dementia, and other dementia.

Basal Forebrain Impairment: Understanding the Mnemonic Function of the Septal Region Translates in Therapeutic Advances

The basal forebrain is one of the three major brain circuits involved in episodic memory formation together with the hippocampus and the diencephalon. The dysfunction of each of these regions is known to cause anterograde amnesia. While the hippocampal pyramidal neurons are known to encode episodic information and the diencephalic structures are known to provide idiothetic information, the contribution of the basal forebrain to memory formation has been exclusively associated with septo-hippocampal cholinergic signaling. Research data from the last decade broadened our understanding about the role of septal region in memory formation. Animal studies revealed that septal neurons process locomotor, rewarding and attentional stimuli. The integration of these signals results in a systems model for the mnemonic function of the medial septum that could guide new therapeutic strategies for basal forebrain impairment (BFI). BFI includes the disorders characterized with basal forebrain amnesia and neurodegenerative disorders that affect the basal forebrain. Here, we demonstrate how the updated model of septal mnemonic function can lead to innovative translational treatment approaches that include pharmacological, instrumental and behavioral techniques.

Long-term use of pharmacological treatment in Alzheimer's disease: a retrospective cohort study in real-world clinical practice

PURPOSE

To assess the impact of long-term use of different drugs commonly prescribed in Alzheimer's disease (AD) on its clinical course and to identify clinical and therapeutic factors associated with a delay in AD progression.

METHODS

We retrospectively enrolled 50 patients visited at the Neurology Unit, Careggi University Hospital (Florence), followed for at least 24 months. AD diagnosis was made according to clinical diagnostic criteria for probable/possible AD dementia, always supported at least by one biomarker. Clinical features, MMSE scores evaluated at diagnosis and every 6 months, and AD drugs used for at least 6 months, were recorded. Cox regression analysis was performed to estimate the hazard ratio (HR) for AD progression, assuming as the "final event," the progression to a more severe disease stage, defined as the achievement of an MMSE score less than 10.

RESULTS

At baseline, the median MMSE score was 22. During follow-up (median of 41 months), 56% of patients progressed to a more severe disease stage. The use of memantine, either alone (HR 0.24; 95% CI 0.09-0.60) or combined with acetylcholinesterase inhibitors (HR 0.35; 95% CI 0.14-0.88) and a higher MMSE score at baseline (HR 0.82; 95% CI 0.70-0.96) were associated with a significantly lower risk of AD progression.

CONCLUSION

Nowadays, effective disease-modifying therapy for AD is missing. Nevertheless, when the diagnosis is established, our results support the advantage of long-term use of available pharmacological treatments, especially in combination, in delaying AD progression to its more severe disease stage.

Comparative safety and efficacy of cognitive enhancers for Alzheimer's dementia: a systematic review with individual patient data network meta-analysis

OBJECTIVE

To examine the comparative efficacy and safety of cognitive enhancers by patient characteristics for managing Alzheimer's dementia (AD).

DESIGN

Systematic review and individual patient data (IPD) network meta-analysis (NMA) based on our previously published systematic review and aggregate data NMA.

DATA SOURCES

MEDLINE, Embase, Cochrane Methodology Register, CINAHL, AgeLine and Cochrane Central Register of Controlled Trials up to March 2016.

PARTICIPANTS

80 randomised controlled trials (RCTs) including 21 138 adults with AD, and 12 RCTs with IPD including 6906 patients.

INTERVENTIONS

Cognitive enhancers (donepezil, rivastigmine, galantamine and memantine) alone or in any combination against other cognitive enhancers or placebo.

DATA EXTRACTION AND SYNTHESIS

We requested IPD from authors, sponsors and data sharing platforms. When IPD were not available, we used aggregate data. We appraised study quality with the Cochrane risk-of-bias. We conducted a two-stage random-effects IPD-NMA, and assessed their findings using CINeMA (Confidence in Network Meta-Analysis).

PRIMARY AND SECONDARY OUTCOMES

We included trials assessing cognition with the Mini-Mental State Examination (MMSE), and adverse events.

RESULTS

Our IPD-NMA compared nine treatments (including placebo). Donepezil (mean difference (MD)=1.41, 95% CI: 0.51 to 2.32) and donepezil +memantine (MD=2.57, 95% CI: 0.07 to 5.07) improved MMSE score (56 RCTs, 11 619 participants; CINeMA score: moderate) compared with placebo. According to P-score, oral rivastigmine (OR=1.26, 95% CI: 0.82 to 1.94, P-score=16%) and donepezil (OR=1.08, 95% CI: 0.87 to 1.35, P-score=30%) had the least favourable safety profile, but none of the estimated treatment effects were sufficiently precise when compared with placebo (45 RCTs, 15 649 patients; CINeMA score: moderate to high). For moderate-to-severe impairment, donepezil, memantine and their combination performed best, but for mild-to-moderate impairment donepezil and transdermal rivastigmine ranked best. Adjusting for MMSE baseline differences, oral rivastigmine and galantamine improved MMSE score, whereas when adjusting for comorbidities only oral rivastigmine was effective.

CONCLUSIONS

The choice among the different cognitive enhancers may depend on patient's characteristics. The MDs of all cognitive enhancer regimens except for single-agent oral rivastigmine, galantamine and memantine, against placebo were clinically important for cognition (MD larger than 1.40 MMSE points), but results were quite imprecise. However, two-thirds of the published RCTs were associated with high risk of bias for incomplete outcome data, and IPD were only available for 15% of the included RCTs.

PROSPERO REGISTRATION NUMBER

CRD42015023507.

Ferulic acid produces neuroprotection against radiation-induced neuroinflammation by affecting NLRP3 inflammasome activation

PURPOSE

After radiation therapy of brain tumors, radiation-induced cognitive impairment is a common and severe complication. Neuroinflammation mediated by microglia is a critical event that accelerates cognitive or functional decline. Ferulic acid (FA), a phenolic plant component, possesses multiple pharmacological effects, such as anti-inflammatory and anti-radiation. The current research attempts to ascertain the protection of FA on radiation-induced neuroinflammation and the mechanism of this effect.

MATERIALS AND METHODS

C57BL/6 mice were irradiated with ⁶⁰Co γ-ray to establish a brain injury model. The Morris water maze experiment was used to observe the effects of FA on the spatial learning and memory impairment of irradiated mice. The pathological changes of hippocampal tissue were observed by HE staining. Besides, microglia BV-2 cell lines were used to study the anti-neuroinflammatory impacts of FA on radiation-induced microglial activation and further elucidate the potential mechanisms influencing FA-mediated neuroprotective properties. The cell morphological changes were observed using an optical microscope. The cytotoxicity of FA and radiation to BV-2 cells was determined using the CCK-8 assay. Additionally, Western blot and quantitative real-time PCR detected the expression and transcription of NLRP3 inflammasome and pro-inflammatory cytokines in hippocampus and BV-2 cells.

RESULTS

FA could enhance learning and memory capacity and ameliorate pathological changes in the hippocampal tissues of irradiated mice. The cell radiation injury model was established by 8 Gy ⁶⁰Co γ-ray, and the concentration of subsequent administration was determined to be 2.5, 5, and 10 μmol/L. Furthermore, FA could suppress the transcription and expression of NLRP3 in hippocampal tissue and microglia, and also the increased secretion of pro-inflammatory factors.

CONCLUSION

This study established that FA targeting the NLRP3 inflammasome has a neuroprotective effect against radiation-induced nerve damage, implying that FA might have some potential in the treatment of radiation-induced cognitive impairment.

Targeting the M1 muscarinic acetylcholine receptor in Alzheimer’s disease

Alzheimer’s disease (AD) remains a major cause of morbidity and mortality worldwide, and despite extensive research, only a few drugs are available for management of the disease. One strategy has been to up-regulate cholinergic neurotransmission to improve cognitive function, but this approach has dose-limiting adverse effects. To avoid these adverse effects, new drugs that target specific receptor subtypes of the cholinergic system are needed, and the M1 subtype of muscarinic acetylcholine receptor (M1-mAChR) has been shown to be a good target for this approach. By using several strategies, M1-mAChR ligands have been developed and trialled in preclinical animal models and in human studies, with varying degrees of success. This article reviews the different approaches to targeting the M1-mAChR in AD and discusses the advantages and limitations of these strategies. The factors to consider in targeting the M1-mAChR in AD are also discussed.

CCCDTD5 recommendations on the deprescribing of cognitive enhancers in dementia

INTRODUCTION

Cognitive enhancers (ie, cholinesterase inhibitors and memantine) can provide symptomatic benefit for some individuals with dementia; however, there are circumstances in which the risks of continuing treatment may potentially outweigh benefits. The decision to deprescribe cognitive enhancers must consider each patient's preferences, treatment indications, current clinical status and symptoms, prognosis, and dementia type.

METHODS

The 5th Canadian Consensus Conference on the Diagnosis and Treatment of Dementia (CCCDTD5) established a subcommittee of experts to review current evidence on the deprescribing of cognitive enhancers. The questions answered by this group included: When should cognitive enhancers be deprescribed in persons with dementia and mild cognitive impairment? How should cognitive enhancers be deprescribed? And, what clinical factors should be considered when deprescribing cognitive enhancers?

RESULTS

Patient and care-partner preferences should be incorporated into all decisions to deprescribe cognitive enhancers. Cognitive enhancers should be discontinued in individuals without ongoing evidence of benefit or when the indication for cognitive enhancer use was inappropriate (eg, mild cognitive impairment). Deprescribing should occur gradually and cognitive enhancers should be reinitiated if patients' cognition or function deteriorates. Cognitive enhancers should be continued in individuals whose neuropsychiatric symptoms improve in response to treatment. Clinicians should not deprescribe cognitive enhancers in individuals with significant neuropsychiatric symptoms until symptoms have stabilized.

CONCLUSION

CCCDTD5 deprescribing recommendations provide evidence-informed recommendations related to cognitive enhancer deprescribing that will facilitate shared decision making among patients, care partners, and clinicians.

Effects of water‐soluble mangosteen extract on cognitive function and neuropsychiatric symptoms in patients with mild to moderate Alzheimer's disease (WECAN‐AD): A randomized controlled trial

Introduction

The water‐soluble mangosteen pericarp extract's (WME) effect was investigated in Alzheimer's disease (AD).

Methods

The participants received 4 mg/kg/day of WME for 24 weeks (low dose, n = 33), 4 mg/kg/day for 12 weeks and then 8 mg/kg/day for 12 weeks (high dose, n = 33); or a placebo (n = 42). The outcomes were neuropsychiatric test scores, safety, tolerability, and the blood 4‐hydroxynonenal level.

Results

The proportion of participants who achieved the minimum clinically important difference for the Alzheimer's Disease Assessment Scale–Cognitive Subscale (ADAS‐Cog; –2.6 points) at 24 weeks was significantly higher in the low‐dose group (and a trend in the high‐dose group) than in the placebo group. WME appeared safe and well tolerated. At 24 weeks, the 4‐hydroxynonenal level declined in both intervention groups. The participants with a 5% reduction in this level showed greater ADAS‐Cog improvements.

Conclusion

WME is a safe and well‐tolerated cognitive enhancer in AD with varying benefits across individuals based on antioxidative response.

A New Insight into an Alternative Therapeutic Approach to Restore Redox Homeostasis and Functional Mitochondria in Neurodegenerative Diseases

Neurodegenerative diseases are accompanied by oxidative stress and mitochondrial dysfunction, leading to a progressive loss of neuronal cells, formation of protein aggregates, and a decrease in cognitive or motor functions. Mitochondrial dysfunction occurs at the early stage of neurodegenerative diseases. Protein aggregates containing oxidatively damaged biomolecules and other misfolded proteins and neuroinflammation have been identified in animal models and patients with neurodegenerative diseases. A variety of neurodegenerative diseases commonly exhibits decreased activity of antioxidant enzymes, lower amounts of antioxidants, and altered cellular signalling. Although several molecules have been approved clinically, there is no known cure for neurodegenerative diseases, though some drugs are focused on improving mitochondrial function. Mitochondrial dysfunction is caused by oxidative damage and impaired cellular signalling, including that of peroxisome proliferator-activated receptor gamma coactivator 1α. Mitochondrial function can also be modulated by mitochondrial biogenesis and the mitochondrial fusion/fission cycle. Mitochondrial biogenesis is regulated mainly by sirtuin 1, NAD⁺, AMP-activated protein kinase, mammalian target of rapamycin, and peroxisome proliferator-activated receptor γ. Altered mitochondrial dynamics, such as increased fission proteins and decreased fusion products, are shown in neurodegenerative diseases. Due to the restrictions of a target-based approach, a phenotype-based approach has been performed to find novel proteins or pathways. Alternatively, plasma membrane redox enzymes improve mitochondrial function without the further production of reactive oxygen species. In addition, inducers of antioxidant response elements can be useful to induce a series of detoxifying enzymes. Thus, redox homeostasis and metabolic regulation can be important therapeutic targets for delaying the progression of neurodegenerative diseases.

Comparative Value of Cholinesterase Inhibitors and Memantine in Persons with Moderate-to-Severe Alzheimer's Disease in the United States: A Cost-Effectiveness Analysis

Background:

Pharmacological treatment of Alzheimer’s disease (AD) involves symptomatic improvement of cognition using cholinesterase inhibitors (ChEIs) and memantine. The cost-effectiveness of these medications will guide decision-makers in making judicious use of scarce healthcare resources, particularly during the advanced disease stages.

Objective:

To evaluate the cost-effectiveness of ChEIs, memantine, and ChEI-memantine combinations in persons with moderate-to-severe AD from the US healthcare perspective.

Methods:

This pharmacoeconomic evaluation study used a state-transition Markov cohort model to simulate the costs and effectiveness of ChEI-memantine combinations compared with monotherapies of ChEI (donepezil, galantamine and rivastigmine) and memantine in persons with moderate-to-severe AD over a lifetime horizon with a 1-year cycle length. We estimated expected quality-adjusted life-years (QALYs), costs (in 2020 $US), net monetary benefits, and incremental cost-effectiveness ratios (ICERs). We discounted future costs and QALYs at the rate of 3%.

Results:

In this study, donepezil monotherapy, galantamine-memantine combination, and rivastigmine transdermal patch formed the cost-effectiveness frontier. Findings suggests that rivastigmine transdermal patch is the optimal treatment strategy at a willingness-to-pay (WTP) threshold of $150,000/QALY (ICER = $93,307/QALY [versus donepezil monotherapy]). Results across subgroups by age and sex also suggest that the rivastigmine transdermal patch is the optimal treatment strategy with the highest net benefit.

Conclusion:

From the US healthcare perspective, we found that, for persons with moderate-to-severe AD at a WTP threshold of $150,000/QALY, the rivastigmine transdermal patch is the most cost-effective pharmacological treatment option. Given that the transdermal patch is a preferred route of administration for persons with AD and their caregivers due to its convenience, our findings provide additional incentives for its use.

Adverse Drug Reactions of Acetylcholinesterase Inhibitors in Older People Living with Dementia: A Comprehensive Literature Review

The rising of global geriatric population has contributed to increased prevalence of dementia. Dementia is a neurodegenerative disease, which is characterized by progressive deterioration of cognitive functions, such as judgment, language, memory, attention and visuospatial ability. Dementia not only has profoundly devastating physical and psychological health outcomes, but it also poses a considerable healthcare expenditure and burdens. Acetylcholinesterase inhibitors (AChEIs), or so-called anti-dementia medications, have been developed to delay the progression of neurocognitive disorders and to decrease healthcare needs. AChEIs have been widely prescribed in clinical practice for the treatment of Alzheimer's disease, which account for 70% of dementia. The rising use of AChEIs results in increased adverse drug reactions (ADRs) such as cardiovascular and gastrointestinal adverse effects, resulting from overstimulation of peripheral cholinergic activity and muscarinic receptor activation. Changes in pharmacokinetics (PK), pharmacodynamics (PD) and pharmacogenetics (PGx), and occurrence of drug interactions are said to be major risk factors of ADRs of AChEIs in this population. To date, comprehensive reviews in ADRs of AChEIs have so far been scarcely studied. Therefore, we aimed to recapitulate and update the diverse aspects of AChEIs, including the mechanisms of action, characteristics and risk factors of ADRs, and preventive strategies of their ADRs. The collation of this knowledge is essential to facilitate efforts to reduce ADRs of AChEIs.

Dextran Sodium Sulphate-Induced Gastrointestinal Injury Further Aggravates the Impact of Galantamine on the Gastric Myoelectric Activity in Experimental Pigs

Galantamine has been used as a treatment for Alzheimer disease. It has a unique, dual mode of action (inhibitor of acetylcholinesterase and allosteric modulator of nicotinic acetylcholine receptors). Nausea (in about 20%), vomiting (10%) and diarrhoea (5–7%) are the most common side effects. The aim of this study was to assess the effect of galantamine on porcine gastric myoelectric activity without (Group A) and with (Group B) dextran sodium sulphate (DSS)-induced gastrointestinal injury. Galantamine hydrobromide was administrated to twelve pigs as a single intragastric dose (24 mg). Gastric myoelectric activity was investigated by electrogastrography (EGG). Basal (15 min before galantamine administration) and study recordings after galantamine administration (300 min) were evaluated using a running spectral analysis. Results were expressed as dominant frequency of gastric slow waves and power analysis (areas of amplitudes). Altogether, 3780 one-minute EGG recordings were evaluated. In Group A, power was steady from basal values for 180 min, then gradually decreased till 270 min (p = 0.007). In Group B, there was a rapid gradual fall from basal values to those after 120 min (p = 0.007) till 300 min (p ˂ 0.001). In conclusion, galantamine alone revealed an unfavourable effect on porcine myoelectric activity assessed by gastric power. It can be a plausible explanation of galantamine-associated dyspepsia in humans. DSS caused further profound decrease of EGG power. That may indicate that underlying inflammatory, ischaemic or NSAIDs-induced condition of the intestine in humans can have aggravated the effect of galantamine on gastric myoelectric activity.

Primary care physician volume and quality of care for older adults with dementia: a retrospective cohort study

Background

Some jurisdictions restrict primary care physicians’ daily patient volume to safeguard quality of care for complex patients. Our objective was to determine whether people with dementia receive lower-quality care if their primary care physician sees many patients daily.

Methods

Population-based retrospective cohort study using health administrative data from 100,256 community-living adults with dementia aged 66 years or older, and the 8,368 primary care physicians who cared for them in Ontario, Canada. Multivariable Poisson GEE regression models tested whether physicians’ daily patient volume was associated with the adjusted likelihood of people with dementia receiving vaccinations, prescriptions for cholinesterase inhibitors, benzodiazepines, and antipsychotics from their primary care physician.

Results

People with dementia whose primary care physicians saw ≥ 30 patients daily were 32% (95% CI: 23% to 41%, p < 0.0001) and 25% (95% CI: 17% to 33%, p < 0.0001) more likely to be prescribed benzodiazepines and antipsychotic medications, respectively, than patients of primary care physicians who saw < 20 patients daily. Patients were 3% (95% CI: 0.4% to 6%, p = 0.02) less likely to receive influenza vaccination and 8% (95% CI: 4% to 13%, p = 0.0001) more likely to be prescribed cholinesterase inhibitors if their primary care physician saw ≥ 30 versus < 20 patients daily.

Conclusions

People with dementia were more likely to receive both potentially harmful and potentially beneficial medications, and slightly less likely to be vaccinated by high-volume primary care physicians.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12875-021-01398-9.

Using a distribution-based approach and systematic review methods to derive minimum clinically important differences

Background

Clinical interpretation of changes measured on a scale is dependent on knowing the minimum clinically important difference (MCID) for that scale: the threshold above which clinicians, patients, and researchers perceive an outcome difference. Until now, approaches to determining MCIDs were based upon individual studies or surveys of experts. However, the comparison of meta-analytic treatment effects to a MCID derived from a distribution of standard deviations (SDs) associated with all trial-specific outcomes in a meta-analysis could improve our clinical understanding of meta-analytic treatment effects.

Methods

We approximated MCIDs using a distribution-based approach that pooled SDs associated with baseline mean or mean change values for two scales (i.e. Mini-Mental State Exam [MMSE] and Alzheimer Disease Assessment Scale – Cognitive Subscale [ADAS-Cog]), as reported in parallel randomized trials (RCTs) that were included in a systematic review of cognitive enhancing medications for dementia (i.e. cholinesterase inhibitors and memantine). We excluded RCTs that did not report baseline or mean change SD values. We derived MCIDs at 0.4 and 0.5 SDs of the pooled SD and compared our derived MCIDs to previously published MCIDs for the MMSE and ADAS-Cog.

Results

We showed that MCIDs derived from a distribution-based approach approximated published MCIDs for the MMSE and ADAS-Cog. For the MMSE (51 RCTs, 12,449 patients), we derived a MCID of 1.6 at 0.4 SDs and 2 at 0.5 SDs using baseline SDs and we derived a MCID of 1.4 at 0.4 SDs and 1.8 at 0.5 SDs using mean change SDs. For the ADAS-Cog (37 RCTs, 10,006 patients), we derived a MCID of 4 at 0.4 SDs and 5 at 0.5 SDs using baseline SDs and we derived a MCID of 2.6 at 0.4 SDs and 3.2 at 0.5 SDs using mean change SDs.

Conclusion

A distribution-based approach using data included in a systematic review approximated known MCIDs. Our approach performed better when we derived MCIDs from baseline as opposed to mean change SDs. This approach could facilitate clinical interpretation of outcome measures reported in RCTs and systematic reviews of interventions. Future research should focus on the generalizability of this method to other clinical scenarios.

Fall-Related Hospitalizations in Nursing Home Residents Co-Prescribed a Cholinesterase Inhibitor and Beta-Blocker

BACKGROUND/OBJECTIVES

To examine the association between hospitalization for a fall-related injury and the co-prescription of a cholinesterase inhibitor (ChEI) among persons with dementia receiving a beta-blocker, and whether this potential drug-drug interaction is modified by frailty.

DESIGN

Nested case-control study using population-based administrative databases.

SETTING

All nursing homes in Ontario, Canada.

PARTICIPANTS

Persons with dementia aged 66 and older who received at least one beta-blocker between April 2013 and March 2018 following nursing home admission (n = 19,060).

MEASUREMENTS

Cases were persons with dementia with a hospitalization (emergency department visit or acute care admission) for a fall-related injury with concurrent beta-blocker use. Each case (n = 3,038) was matched 1:1 to a control by age (±1 year), sex, cohort entry year, frailty, and history of fall-related injuries. The association between fall-related injury and exposure to a ChEI in the 90 days prior was examined using multivariable conditional logistic regression. Secondary exposures included ChEI type, daily dose, incident versus prevalent use, and use in the prior 30 days. Subgroup analyses considered frailty, age group, sex, and history of hospitalization for fall-related injuries.

RESULTS

Exposure to a ChEI in the prior 90 days occurred among 947 (31.2%) cases and 940 (30.9%) controls. In multivariable models, no association was found between hospitalization for a fall-related injury and prior exposure to a ChEI in persons with dementia dispensed beta-blockers (adjusted odds ratio = .96, 95% confidence interval = .85-1.08). Findings were consistent across secondary exposures and subgroup analyses.

CONCLUSION

Among nursing home residents with dementia receiving beta-blockers, co-prescription of a ChEI was not associated with an increased risk of hospitalization for a fall-related injury. However, we did not assess for its association with falls not leading to hospitalization. This finding could inform clinical guidelines and shared decision making between persons with dementia, caregivers, and clinicians concerning ChEI initiation and/or discontinuation.

An Alzheimer Disease Challenge Model: 24-Hour Sleep Deprivation in Healthy Volunteers, Impact on Working Memory, and Reversal Effect of Pharmacological Intervention: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study

PURPOSE/BACKGROUND

Alzheimer disease (AD) is a public health issue because of the low number of symptomatic drugs and the difficulty to diagnose it at the prodromal stage. The need to develop new treatments and to validate sensitive tests for early diagnosis could be met by developing a challenge model reproducing cognitive impairments of AD. Therefore, we implemented a 24-hour sleep deprivation (SD) design on healthy volunteers in a randomized, double-blind, placebo-controlled, crossover study on 36 healthy volunteers.

METHODS/PROCEDURE

To validate the SD model, cognitive tests were chosen to assess a transient worsening of cognitive functions after SD and a restoration under modafinil as positive control (one dose of 200 mg). Then, the same evaluations were replicated after 15 days of donepezil (5 mg/d) or memantine (10 mg/d). The working memory (WM) function was assessed by the N-back task and the rapid visual processing (RVP) task.

FINDINGS/RESULTS

The accuracy of the N-back task and the reaction time of the RVP revealed the alteration of the WM with SD and its restoration with modafinil (changes in score after SD compared with baseline before SD), respectively, in the placebo group and in the modafinil group (-0.2% and +1.0% of satisfactory answers, P = 0.022; +21.3 and +1.9 milliseconds of reaction time, P = 0.025). Alzheimer disease drugs also tended to reverse this deterioration: the accuracy of the N-back task was more stable through SD (compared with -3.0% in the placebo group, respectively, in the memantine group and in the donepezil group: -1.4% and -1.6%, P = 0.027 and P = 0.092) and RVP reaction time was less impacted (compared with +41.3 milliseconds in the placebo group, respectively, in the memantine group and in the donepezil group: +16.1 and +29.3 milliseconds, P = 0.034 and P = 0.459).

IMPLICATIONS/CONCLUSIONS

Our SD challenge model actually led to a worsening of WM that was moderated by both modafinil and AD drugs. To use this approach, the cognitive battery, the vulnerability of the subjects to SD, and the expected drug effect should be carefully considered.

Usage and adherence of antidementia drugs in a memory clinic cohort in Chongqing, Southwest China

BACKGROUND

To investigate the use and adherence of antidementia drugs in elderly patients with dementia from the Memory Clinic of The First Affiliated Hospital of Chongqing Medical University.

METHODS

Patients were recruited from the Memory Clinic of The First Affiliated Hospital of Chongqing Medical University from December 2010 to December 2018. Medical charts were reviewed, including diagnosis, dosage of antidementia medicines, neuropsychological testing scores, and the further questionnaires were conducted via face-to-face or telephone, included duration of treatment, types of antidementia drugs, and reasons for treatment discontinuation.

RESULTS

The data from 422 patients were analysed retrospectively for this study. Three hundred and fifteen were diagnosed with Alzheimer's disease (AD), 67 with mild cognitive impairment (MCI), and 40 with other types of dementia. From the 422 patients, 26.8% were treated with original donepezil (n = 113), 11.6% with generic donepezil (n = 49), 24.6% with memantine (n = 104), 13.3% with huperzine A (n = 56), and 23.7% with a combination of drugs (n = 100). However, 73% of patients discontinued treatment within 1 year of initiation. Patients treated for more than 36 months (37.8%) were more likely to choose combined medication, as compared with patients treated for less than 36 months. Patients with less than 9 years of education (odds ratio (OR): 2.394; 95% CI: 1.508-3.801) were more likely to discontinue treatment than patients with more than 9 years of education. Patients with elevated physical self-maintenance scale (PSMS) scores (OR: 1.195; 95% CI: 1.086-1.316) had a high risk of discontinuation.

CONCLUSIONS

Overall treatment compliance is relatively poor in memory clinics in Chongqing. Our study demonstrates that higher education may lead to better treatment adherence in dementia care. Combination therapy may increase treatment time. However, poorer PSMS scores are a significant risk factor for treatment discontinuation.

Efficacy and Safety of Cholinesterase Inhibitors for Mild Cognitive Impairment:A Systematic Review and Meta-Analysis

BACKGROUND

The clinical benefit of cholinesterase inhibitors (ChEIs) for mild cognitive impairment (MCI) remains inconclusive.

OBJECTIVE

We performed a systematic review and meta-analysis of the efficacy/safety of ChEIs on subjects with MCI.

METHODS

We included randomized controlled trials (RCTs) of ChEIs in subjects with MCI, using cognitive function scores as a primary outcome measure.

RESULTS

Fourteen RCTs (six using donepezil, four using galantamine, and four using rivastigmine) with 5,278 subjects were included. We found no significant difference in cognitive function scores between the ChEIs and placebo groups [standardized mean difference (SMD) = -0.06, p = 0.38, I2 = 76% ]. However, in the secondary outcomes, ChEIs were associated with a lower incidence of progression to dementia compared with placebo (risk ratio = 0.76, the number needed to treat = 20). For safety outcomes, ChEIs were associated with a lower prevalence of fall than placebo. On the other hand, compared with placebo, ChEIs were associated with a higher incidence of discontinuation due to all causes, discontinuation due to adverse events, at least one adverse event, abnormal dreams, diarrhea, dizziness, headache, insomnia, loose stools, muscle cramps, nausea, vomiting, and weight loss.

CONCLUSIONS

Although ChEIs have a slight efficacy in the treatment of MCI, there are many safety issues. Therefore, ChEIs are difficult to recommend for MCI. However, the efficacy and safety of ChEIs on MCI with a biomarker-based diagnosis is unclear. Further RCTs are needed to confirm the efficacy and safety of ChEIs when used for individual neuropathological classifications of MCI.

Pharmacogenetic considerations when prescribing cholinesterase inhibitors for the treatment of Alzheimer's disease

INTRODUCTION

Cholinergic dysfunction, demonstrated in the late 1970s and early 1980s, led to the introduction of acetylcholinesterase inhibitors (AChEIs) in 1993 (Tacrine) to enhance cholinergic neurotransmission as the first line of treatment against Alzheimer's disease (AD). The new generation of AChEIs, represented by Donepezil (1996), Galantamine (2001) and Rivastigmine (2002), is the only treatment for AD to date, together with Memantine (2003). AChEIs are not devoid of side-effects and their cost-effectiveness is limited. An option to optimize the correct use of AChEIs is the implementation of pharmacogenetics (PGx) in the clinical practice.

AREAS COVERED

(i) The cholinergic system in AD, (ii) principles of AD PGx, (iii) PGx of Donepezil, Galantamine, Rivastigmine, Huperzine and other treatments, and (iv) practical recommendations.

EXPERT OPINION

The most relevant genes influencing AChEI efficacy and safety are APOE and CYPs. APOE-4 carriers are the worst responders to AChEIs. With the exception of Rivastigmine (UGT2B7, BCHE-K), the other AChEIs are primarily metabolized via CYP2D6, CYP3A4, and UGT enzymes, with involvement of ABC transporters and cholinergic genes (CHAT, ACHE, BCHE, SLC5A7, SLC18A3, CHRNA7) in most ethnic groups. Defective variants may affect the clinical response to AChEIs. PGx geno-phenotyping is highly recommended prior to treatment.

Dual-acting agents for improving cognition and real-world function in Alzheimer's disease: Focus on 5-HT6 and D3 receptors as hubs

To date, there are no interventions that impede the inexorable progression of Alzheimer's disease (AD), and currently-available drugs cholinesterase (AChE) inhibitors and the N-Methyl-d-Aspartate receptor antagonist, memantine, offer only modest symptomatic benefit. Moreover, a range of mechanistically-diverse agents (glutamatergic, histaminergic, monoaminergic, cholinergic) have disappointed in clinical trials, alone and/or in association with AChE inhibitors. This includes serotonin (5-HT) receptor-6 antagonists, despite compelling preclinical observations in rodents and primates suggesting a positive influence on cognition. The emphasis has so far been on high selectivity. However, for a multi-factorial disorder like idiopathic AD, 5-HT6 antagonists possessing additional pharmacological actions might be more effective, by analogy to "multi-target" antipsychotics. Based on this notion, drug discovery programmes have coupled 5-HT6 blockade to 5-HT4 agonism and inhibition of AchE. Further, combined 5-HT6/dopamine D3 receptor (D3) antagonists are of especial interest since D3 blockade mirrors 5-HT6 antagonism in exerting broad-based pro-cognitive properties in animals. Moreover, 5-HT6 and dopamine D3 antagonists promote neurocognition and social cognition via both distinctive and convergent actions expressed mainly in frontal cortex, including suppression of mTOR over-activation and reinforcement of cholinergic and glutamatergic transmission. In addition, 5-HT6 blockade affords potential anti-anxiety, anti-depressive and anti-epileptic properties, and antagonising 5-HT6 receptors may be associated with neuroprotective ("disease-modifying") properties. Finally D3 antagonism may counter psychotic episodes and D3 receptors themselves offer a promising hub for multi-target agents. The present article reviews the status of "R and D" into multi-target 5-HT6 and D3 ligands for improved treatment of AD and other neurodegenerative disorders of aging. This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'.

Type 2 diabetes and cognitive dysfunction-towards effective management of both comorbidities

Type 2 diabetes and cognitive dysfunction are highly prevalent disorders worldwide. Although type 2 diabetes is associated with an increased risk of dementia, awareness of the link between the two conditions is poor, and few recommendations are available to guide clinicians about how to approach cognitive dysfunction in people with diabetes. Clinical guidelines in diabetes have only recently begun to emphasise the importance of cognitive impairment in diabetes and its management. This Series paper aims to synthesise knowledge about the link between diabetes and cognitive dysfunction, issues pertaining to screening and diagnosis of cognitive impairment and dementia in those with type 2 diabetes, management of diabetes in people with cognitive dysfunction (accounting for age and frailty), and emerging therapies for prevention. A conceptual framework for approaching screening and diagnosis is included, and future research directions to guide the field forward are suggested.

Application of Discrete-Event Simulation in Health Technology Assessment: A Cost-Effectiveness Analysis of Alzheimer's Disease Treatment Using Real-World Evidence in Thailand

OBJECTIVES

Decision-analytic models for Alzheimer's disease (AD) have been advanced to a discrete-event simulation (DES), in which individual-level modeling of disease progression across continuous severity spectra become feasible. This study aimed to apply DES to perform cost-effectiveness analysis of AD treatment in Thailand.

METHODS

A data set of Thai AD patients, representing unique demographic and clinical characteristics, was bootstrapped to generate a baseline cohort of 50 000 patients. Each patient was cloned and assigned to donepezil, galantamine, rivastigmine, memantine, or no treatment. Correlated changes in cognitive and behavioral status over time were developed using patient-level data. Treatment effects were obtained from the most recent network meta-analysis. Treatment persistence; mortality; and predictive equations for functional status, costs (Thai baht in 2017), and quality-adjusted life-year (QALY) were derived from country-specific real-world data.

RESULTS

From a societal perspective, only the prescription of donepezil to AD patients with all disease-severity levels was found to be cost-effective (incremental cost-effectiveness ratio): 138 524 Thai baht/QALY ($4062/QALY)]. Regardless of whether the treatment-stopping rule when the mini-mental state examination score <10 was introduced, providing early treatment with donepezil to mild AD patients further reduced the incremental cost-effectiveness ratio. Extensive sensitivity analyses indicated robust simulation findings.

CONCLUSIONS

Discrete-event simulation greatly enhances the real-world representativeness of decision-analytic models for AD. Donepezil is the most cost-effective treatment option for AD in Thailand and is worth being considered for universal financial coverage. Application of DES in heath technology assessment should be encouraged, especially when the validity of the model is questionable with classical modeling methods.

What can we learn from the past about the future of gerontology: Using natural language processing to examine the field of gerontology

OBJECTIVES

We thematically classified all titles of eight top psychological and social gerontology journals over a period of six decades, between 1961 and February, 2020. This was done in order to provide a broad overview of the main topics that interest the scientific community over time and place.

METHODS

We used natural language processing in order to analyze the data. In order to capture the diverse thematic clusters covered by the journals, a cluster analysis, based on "topic detection" was conducted.

RESULTS

A total of 15,566 titles were classified into 38 thematic clusters. These clusters were then compared over time and geographic location. The majority of titles fell into a relatively small number of thematic clusters and a large number of thematic clusters was hardly addressed. The most frequently addressed thematic clusters were: a) Cognitive functioning, b) Long term care and formal care, c) Emotional and personality functioning, d) health and e) Family and informal care. The least frequently addressed thematic clusters were: a) Volunteering, b) Sleep, c) Addictions, d) Suicide, and e) Nutrition. There was limited variability over time and place with regard to the most frequently addressed themes.

Prevalence of and risk factors for adverse events in Alzheimer's patients receiving anti-dementia drugs in at-home care

OBJECTIVE

The objective of this study was to clarify the types and prevalence of, and the risk factors for, the adverse events that occur in patients receiving anti-dementia drugs.

METHODS

A questionnaire survey was conducted. The respondents were pharmacists who were dispensing anti-dementia drugs. The pharmacists responded to questions about patients who were receiving anti-dementia drugs delivered to them at home by the pharmacists. The survey questions included questions about whether or not the patients experienced adverse reactions to the drugs, about the patients' background characteristics, about the numbers of drugs the patients were taking when the pharmacists first visited the patients at home, and about the pharmacists' assessments of the appropriateness of the use of the anti-dementia drugs.

RESULTS

Data were collected on 3712 patients from 1673 pharmacies in a nationwide survey. Anti-dementia drugs had been prescribed to 863 of these patients; and 801 (92.8%) of these 863 patients were 75 years of age or older, and. confirmed adverse events occurred in 170 (21%) of these 863 patients. The most common adverse event was excitation/anxiety, at 45.1%. A multivariate analysis found that polypharmacy (10 or more types of drugs per day) (P = 0.030), inappropriate use (P = 0.002), and irregular medication use (P = 0.034) were risk factors.

INTERPRETATION

In order to avoid adverse events when using anti-dementia drugs, doctors and pharmacists should carefully examine the prescribing of multiple medications, assess the applicability of the use of anti-dementia drugs, and investigate how to best manage patients' drug use.

Risk for Health Events After Deprescribing Acetylcholinesterase Inhibitors in Nursing Home Residents With Severe Dementia

BACKGROUND/OBJECTIVE

Reevaluation of the appropriateness of acetylcholinesterase inhibitors (AChEIs) is recommended in older adults with severe dementia, given the lack of strong evidence to support their continued effectiveness and risk for medication-induced adverse events. We sought to evaluate the impact of deprescribing AChEIs on risk of all-cause events (hospitalizations, emergency department visits, and mortality) and serious falls or fractures in older nursing home (NH) residents with severe dementia.

DESIGN

Analysis of 2015 to 2016 data from Medicare claims, Part D prescriptions, Minimum Data Set (MDS) version 3.0, Area Health Resource File, and Nursing Home Compare. Marginal structural models with inverse probability of treatment weights were used to evaluate the association of deprescribing AChEIs and all-cause negative events as well as serious falls or fractures.

SETTING

US Medicare-certified NHs.

PARTICIPANTS

Nonskilled NH residents, aged 65 years and older, with severe dementia receiving AChEIs within the first 14 days of an MDS assessment in 2016 (n = 37 106).

RESULTS

The sample was primarily white (78.7%), female (75.5%), and aged 80 years or older (77.4%). Deprescribing AChEIs was associated with an increased likelihood of all-cause negative events in unadjusted models (odds ratio [OR] = 1.17; 95% confidence interval [CI] = 1.11-1.23; P < .01), but not in fully adjusted models (adjusted OR [aOR] = 1.00; 95% CI = 0.94-1.06; P = .94). By contrast, deprescribing was associated with a reduced likelihood of serious falls or fractures in unadjusted models (OR = 0.59; 95% CI = 0.52-0.66; P < .001) and remained significant in adjusted models (aOR = 0.64; 95% CI = 0.56-0.73; P < .001).

CONCLUSION

Deprescribing AChEIs was not associated with a significant increase in the likelihood for all-cause negative events and was associated with a reduced likelihood of falls and fractures in older NH residents with dementia. Our findings suggest that deprescribing AChEIs is a reasonable approach to reduce the risk of serious falls or fractures without increasing the risk for all-cause events. J Am Geriatr Soc 68:699-707, 2020.

Current and Future Treatments in Alzheimer Disease: An Update

Disease-modifying treatment strategies for Alzheimer disease (AD) are still under extensive research. Nowadays, only symptomatic treatments exist for this disease, all trying to counterbalance the neurotransmitter disturbance: 3 cholinesterase inhibitors and memantine. To block the progression of the disease, therapeutic agents are supposed to interfere with the pathogenic steps responsible for the clinical symptoms, classically including the deposition of extracellular amyloid β plaques and intracellular neurofibrillary tangle formation. Other underlying mechanisms are targeted by neuroprotective, anti-inflammatory, growth factor promotive, metabolic efficacious agents and stem cell therapies. Recent therapies have integrated multiple new features such as novel biomarkers, new neuropsychological outcomes, enrollment of earlier populations in the course of the disease, and innovative trial designs. In the near future different specific agents for every patient might be used in a “precision medicine” context, where aberrant biomarkers accompanied with a particular pattern of neuropsychological and neuroimaging findings could determine a specific treatment regimen within a customized therapeutic framework. In this review, we discuss potential disease-modifying therapies that are currently being studied and potential individualized therapeutic frameworks that can be proved beneficial for patients with AD.

Design, Synthesis, and In Vitro Evaluation of Hydroxybenzimidazole-Donepezil Analogues as Multitarget-Directed Ligands for the Treatment of Alzheimer's Disease

A series of multi-target-directed ligands (MTDLs), obtained by attachment of a hydroxyphenylbenzimidazole (BIM) unit to donepezil (DNP) active mimetic moiety (benzyl-piperidine/-piperazine) was designed, synthesized, and evaluated as potential anti-Alzheimer's disease (AD) drugs in terms of biological activity (inhibition of acetylcholinesterase (AChE) and β-amyloid (Aβ) aggregation), metal chelation, and neuroprotection capacity. Among the DNP-BIM hybrids studied herein, the structural isomerization did not significantly improve the biological properties, while some substitutions, namely fluorine atom in each moiety or the methoxy group in the benzyl ring, evidenced higher cholinergic AChE activity. All the compounds are able to chelate Cu and Zn metal ions through their bidentate BIM moieties, but compound 5, containing a three-dentate chelating unit, is the strongest Cu(II) chelator. Concerning the viability on neuroblastoma cells, compounds 9 and 10 displayed the highest reduction of Aβ-induced cell toxicity. In silico calculations of some pharmacokinetic descriptors indicate that all the compounds but the nitro derivatives have good potential oral-bioavailability. Overall, it can be concluded that most of the studied DNP-BIM conjugates showed quite good anti-AD properties, therefore deserving to be considered in further studies with the aim of understanding and treating AD.

Donepezil-based hybrids as multifunctional anti-Alzheimer's disease chelating agents: Effect of positional isomerization

The intricate and multifactorial nature of Alzheimer's disease (AD) requires the development of compounds able to hit different pathophysiological targets, such as cholinergic dysfunction, deposits of amyloid beta (Aβ) peptide and metal dyshomeostasis. In order to continue the search for new anti-AD drugs, a design strategy was once more followed based on repositioning donepezil (DNP) drug, by ortho-attaching a benzylpiperidine mimetic of DNP moiety to a hydroxyphenyl-benzimidazole (BIM) chelating unit (compound 1). Herein, compound 1 and a positional isomer 2 are compared in terms of their potential multiple properties: both present good acetylcholinesterase (AChE) inhibition (low μmolar range) and are moderate/good inhibitors of Aβ self- and Cu-mediated aggregation, the inhibition process being mainly due to ligand intercalation between the β-sheets of the fibrils; compound 1 has a higher chelating capacity towards Cu²⁺ and Zn²⁺ (pCu = 14.3, pZn = 6.4, pH 7.4, C_L/C_M = 10, C_M = 10^-6 M) than 2 (pCu = 10.7, pZn = 6.3), attributed to its ability to establish a tridentate (N,O,O) coordination to the metal ion. Both compounds are eligible as drug candidates for oral administration but compound 1 shows improved neuroprotective role by completely preventing Aβ-induced cell toxicity.

Framework of treating Alzheimer’s dementia

Current treatment paradigm in Alzheimer’s disease (AD) involves multiple approaches combining pharmacological and nonpharmacological intervention to mitigate the clinical symptoms, slow the progressive loss of cognitive and functional abilities, or modify the disease course. So far, beyond anti-cholinesterase inhibitors (AChEIs), donepezil, rivastigmine, galantamine, and antagonist of N-methyl-D-aspartic acid (NMDA) receptor, there are no newly approved medicines to treat AD. Under pharmacological treatment, the personal characteristic and the intra-individual therapeutic evaluations to examine various cognitive domains, behavioral and psychological problems, and global function should be considered when choosing any of AChEIs. The use of optimal dosage referring to the expected clinical outcomes and currently reported deficits from patient with AD has become an important issue in clinical treatment. Establishing and maintaining a strong therapeutic alliance to physician, patient, and caregiver is crucial and central to the comprehensive care in AD.

β-Asarone Inhibits Amyloid-β by Promoting Autophagy in a Cell Model of Alzheimer's Disease

Alzheimer's disease (AD) is one of the most common types of dementia that causes memory, thinking, and behavior problems. The most important feature of AD is the gradual irreversible loss of cognitive ability through the formation of amyloid β (Aβ) plaques and neurofibrillary tangles composed of tau protein. The metabolism of Aβ and tau proteins is closely related to and is affected by autophagy. Current research speculates that autophagy dysfunction leads to an increase in harmful proteins in AD. β-Asarone is the main constituent of Acorus tatarinowii Schott and has important effects on the central nervous system. In this paper, we primarily explored the effects of β-asarone on the clearance of noxious proteins and the associated potential mechanisms via autophagy in a PC12 cell AD model. A CCK-8 assay and LDH experiments were used to assess cell viability/toxicity, and SPiDER-βGal was used to detect cellular senescence. The important proteins associated with the pathogenesis of AD including APP, PS1, Aβ, BACE1, and SYN1 were analyzed by immunofluorescence (IF) and Western blot analysis. Antimycin A (A3) and cyclosporine A (CSA) were selected as the activators and inhibitors of autophagy, respectively. LC3, BECN, P62, PINK1, and Parkin protein expression were also examined by IF and Western blot analysis. The data showed that β-asarone administration significantly dose-dependently increased cell proliferation and decreased cytotoxicity; moreover, β-asarone inhibited SA-βGal and improved cell senescence. The results further showed that, compared to the model, APP, PS1, Aβ, BACE1, and p62 were reduced, while SYN1, BECN1, and LC3 were increased after treatment with β-asarone. The results of Canonical Correlation Analysis (CCA) showed a highly significant relationship between the pathological factors of AD and the protein expression of autophagy. In conclusion, our study demonstrated that β-asarone can inhibit Aβ, and this effect may occur by promoting autophagy in a cell model of AD.