Long-term efficacy and safety of donepezil in the treatment of Alzheimer's disease: final analysis of a US multicentre open-label study

The economic case for scaling up health research and development: Lessons from the COVID-19 pandemic

In response to the COVID-19 pandemic, governments directly funded vaccine research and development (R&D), quickly leading to multiple effective vaccines and resulting in enormous health and economic benefits to society. We develop a simple economic model showing this feat could potentially be repeated for other health challenges. Based on inputs from the economic and medical literatures, the model yields estimates of optimal R&D spending on treatments and vaccines for known diseases. Taking a global and societal perspective, we estimate the social benefits of such spending and a corresponding rate of return. Applications to Streptococcus A vaccines and Alzheimer's disease treatments demonstrate the potential of enhanced research and development funding to unlock massive global health and health-related benefits. We estimate that these benefits range from 2 to 60 trillion (2020 US$) and that the corresponding rates of return on R&D spending range from 12% to 23% per year for 30 y. We discuss the current shortfall in R&D spending and public policies that can move current funding closer to the optimal level.

Passive Alzheimer's immunotherapy: A promising or uncertain option?

The US Food and Drug Administration (FDA)'s recent accelerated approval of two anti-amyloid antibodies for treatment of Alzheimer's disease (AD), aducanumab and lecanemab, has caused substantial debate. To inform this debate, we reviewed the literature on randomized clinical trials conducted with eight such antibodies focusing on clinical efficacy, cerebral amyloid removal, amyloid-related imaging abnormalities (ARIAs) and cerebral volumes to the extent such measurements have been reported. Two antibodies, donanemab and lecanemab, have demonstrated clinical efficacy, but these results remain uncertain. We further argue that the decreased amyloid PET signal in these trials is unlikely to be a one-to-one reflection of amyloid removal, but rather a reflection of increased therapy-related brain damage, as supported by the increased incidence of ARIAs and reported loss of brain volume. Due to these uncertainties of benefit and risk, we recommend that the FDA pauses existing approvals and approval of new antibodies until results of phase 4 studies with these drugs are available to inform on these risk-benefit uncertainties. We recommend that the FDA prioritize FDG PET and detection of ARIAs and accelerated brain volume loss with MRI in all trial patients, and neuropathological examination of all patients who die in these phase 4 trials.

Therapeutic Inhalation of Hydrogen Gas for Alzheimer’s Disease Patients and Subsequent Long-Term Follow-Up as a Disease-Modifying Treatment: An Open Label Pilot Study

(1) Background: Alzheimer’s disease (AD) is a progressive and fatal neurodegenerative disorder. Hydrogen gas (H2) is a therapeutic medical gas with multiple functions such as anti-oxidant, anti-inflammation, anti-cell death, and the stimulation of energy metabolism. To develop a disease-modifying treatment for AD through multifactorial mechanisms, an open label pilot study on H2 treatment was conducted. (2) Methods: Eight patients with AD inhaled 3% H2 gas for one hour twice daily for 6 months and then followed for 1 year without inhaling H2 gas. The patients were clinically assessed using the Alzheimer’s Disease Assessment Scale-cognitive subscale (ADAS-cog). To objectively assess the neuron integrity, diffusion tensor imaging (DTI) with advanced magnetic resonance imaging (MRI) was applied to neuron bundles passing through the hippocampus. (3) Results: The mean individual ADAS-cog change showed significant improvement after 6 months of H2 treatment (−4.1) vs. untreated patients (+2.6). As assessed by DTI, H2 treatment significantly improved the integrity of neurons passing through the hippocampus vs. the initial stage. The improvement by ADAS-cog and DTI assessments were maintained during the follow-up after 6 months (significantly) or 1 year (non-significantly). (4) Conclusions: This study suggests that H2 treatment not only relieves temporary symptoms, but also has disease-modifying effects, despite its limitations.

Normalized Theta but Increased Gamma Activity after Acetylcholinesterase Inhibitor Treatment in Alzheimer's Disease: Preliminary qEEG Study

Acetylcholinesterase inhibitors (AChE-I) are the core treatment of mild to severe Alzheimer's disease (AD). However, the efficacy of AChE-I treatment on electroencephalography (EEG) and cognition remains unclear. We aimed to investigate the EEG power and coherence changes, in addition to neuropsychological performance, following a one-year treatment. Nine de-novo AD patients and demographically-matched healthy controls (HC) were included. After baseline assessments, all AD participants started cholinergic therapy. We found that baseline and follow-up gamma power analyzes were similar between groups. Yet, within the AD group after AChE-I intake, individuals with AD displayed higher gamma power compared to their baselines (P < .039). Also, baseline gamma coherence analysis showed lower values in the AD than in HC (P < .048), while these differences disappeared with increased gamma values of AD patients at the follow-up. Within the AD group after AChE-I intake, individuals with AD displayed higher theta and alpha coherence compared to their baselines (all, P < .039). These increased results within the AD group may result from a subclinical epileptiform activity. Even though AChE-I is associated with lower mortality, our results showed a significant effect on EEG power yet can increase the subclinical epileptiform activity. It is essential to be conscious of the seizure risk that treatment may cause.

A Novel Based-Network Strategy to Identify Phytochemicals from Radix Salviae Miltiorrhizae (Danshen) for Treating Alzheimer's Disease

Alzheimer’s disease (AD) is a common age-related neurodegenerative disease that strikes millions worldwide. Herein, we demonstrate a new approach based on network target to identify anti-AD compounds from Danshen. Network pharmacology and molecular docking were employed to establish the DS-AD network, which mainly involved apoptosis of neuron cells. Then network scoring was confirmed via Connectivity Map analysis. M308 (Danshenxinkun D) was an anti-AD candidate with a high score (p < 0.01). Furthermore, we conducted ex vivo experiments with H2O2-treated PC12 cells to verify the neuroprotective effect of Salvia miltiorrhiza-containing plasma (SMP), and UPLC-Q-TOF/MS and RT-qPCR were performed to demonstrate the anti-AD activity of M308 from SMP. Results revealed that SMP could enhance cell viability and level of acetylcholine. AO/EB staining and Mitochondrial membrane potential (MMP) analysis showed that SMP significantly suppressed apoptosis, which may be due to anti-oxidative stress activity. Moreover, the effects of M308 and SMP on expressions of PSEN1, DRD2, and APP mRNA were consistent, and M308 can significantly reverse the expression of PSEN1 and DRD2 mRNA in H2O2-treated PC12 cells. The strategy based on the network could be employed to identify anti-AD compounds from Chinese herbs. Notably, M308 stands out as a promising anti-AD candidate for development.

Prediction and Modeling of Neuropsychological Scores in Alzheimer's Disease Using Multimodal Neuroimaging Data and Artificial Neural Networks

Background: In recent years, predicting and modeling the progression of Alzheimer's disease (AD) based on neuropsychological tests has become increasingly appealing in AD research. Objective: In this study, we aimed to predict the neuropsychological scores and investigate the non-linear progression trend of the cognitive declines based on multimodal neuroimaging data. Methods: We utilized unimodal/bimodal neuroimaging measures and a non-linear regression method (based on artificial neural networks) to predict the neuropsychological scores in a large number of subjects (n = 1143), including healthy controls (HC) and patients with mild cognitive impairment non-converter (MCI-NC), mild cognitive impairment converter (MCI-C), and AD. We predicted two neuropsychological scores, i.e., the clinical dementia rating sum of boxes (CDRSB) and Alzheimer's disease assessment scale cognitive 13 (ADAS13), based on structural magnetic resonance imaging (sMRI) and positron emission tomography (PET) biomarkers. Results: Our results revealed that volumes of the entorhinal cortex and hippocampus and the average fluorodeoxyglucose (FDG)-PET of the angular gyrus, temporal gyrus, and posterior cingulate outperform other neuroimaging features in predicting ADAS13 and CDRSB scores. Compared to a unimodal approach, our results showed that a bimodal approach of integrating the top two neuroimaging features (i.e., the entorhinal volume and the average FDG of the angular gyrus, temporal gyrus, and posterior cingulate) increased the prediction performance of ADAS13 and CDRSB scores in the converting and stable stages of MCI and AD. Finally, a non-linear AD progression trend was modeled to describe the cognitive decline based on neuroimaging biomarkers in different stages of AD. Conclusion: Findings in this study show an association between neuropsychological scores and sMRI and FDG-PET biomarkers from normal aging to severe AD.

Long-acting injectable donepezil microspheres: Formulation development and evaluation

Novel formulations of donepezil (DNP)-loaded microspheres based on a bio-degradable polymer of poly(lactic-co-glycolic acid) (PLGA) with a one-month duration of effect were developed, aimed at reducing dosing frequency and adverse effects and improving patient adherence. The spherical and monodispersed DNP-loaded microspheres were precisely fabricated by the Inventage Lab Precision Particle Fabrication method (IVL-PPFM®) based on micro-electromechanical systems (MEMS) and microfluidic technology. The types of polymers and end-groups, the drug/polymer ratio (DPR), and the routes of administration for DNP were studied to ensure an effective concentration and desired duration. Laser-light particle size analysis and scanning electron microscopy were used to characterization. Also, non-clinical animal models of beagle dogs are used to optimize DNP formulations and evaluate their pharmacokinetic properties. The PK results showed that the DPR was a critical factor in determining the exposure level and duration of DNR release. Furthermore, the lactide ratio, which varied depending upon the type of polymer, determined the hydrophobic interaction and was also an important factor affecting the desired DNP release. Since DNP shows a large inter-species variation between dogs and humans, PK modeling and simulation of the reference drug (i.e., Aricept®) and DNP-loaded microspheres were used for formulation development to overcome and interpret these variations. In addition, the developed PK model was extrapolated to humans using the estimated PK parameter and published clinical pharmacology data for DNP. The predicted PK profile of the DNP-loaded microsphere in humans showed that the formulation with PLGA 7525A and the DPR of 1/9 could maintain drug concentration for a month and could control initial burst release. The data obtained from the study could be used as scientific evidence for decision-making in future formulation development.

Significant effects of cholinesterase inhibitors on tau pathology in the Alzheimer's disease continuum: An in vivo positron emission tomography study

OBJECTIVES

No prior study has assessed the effects of cholinesterase inhibitors (ChEIs) on tau pathology in the brains of patients with Alzheimer's disease (AD). Using positron emission tomography, this study aimed to investigate whether ChEIs reduce tau aggregation in amyloid-positive participants.

METHODS

We analyzed datasets from the Alzheimer's Disease Neuroimaging Initiative and included amyloid-positive participants who had undergone baseline and 1- or 2-year follow-up AV-1451 positron emission tomography scans. We included participants treated with and without ChEIs (ChEIs group: n = 15, No-ChEIs group, n = 45). The annual change in tau aggregation was calculated as the difference in AV-1451- standardized uptake value ratio (SUVR) between the two scans divided by the time between scans. Group differences in annual AV-1451-SUVR change were examined.

RESULTS

We found a significantly lower annual change in AV-1451-SUVR in the Braak 1/2 regions (entorhinal cortex and hippocampus) of participants taking ChEIs. Increased AV-1451-SUVR between the first and second examinations were observed in 22 of 45 participants not taking ChEIs and 2 of 15 participants taking ChEIs. Fisher's exact test showed a significant difference in the ratio of participants with increased AV-1451-SUVR between the groups.

CONCLUSIONS

The findings of this positron emission tomography study suggest that the administration of ChEIs has some neuroprotective effects in patients of the AD continuum, at least in the early stage of the disease progression. This in vivo effect may be mediated via tau, preventing amyloid β-induced neurotoxicity.

Withdrawal or continuation of cholinesterase inhibitors or memantine or both, in people with dementia

BACKGROUND

Dementia is a progressive syndrome characterised by deterioration in memory, thinking and behaviour, and by impaired ability to perform daily activities. Two classes of drug - cholinesterase inhibitors (donepezil, galantamine and rivastigmine) and memantine - are widely licensed for dementia due to Alzheimer's disease, and rivastigmine is also licensed for Parkinson's disease dementia. These drugs are prescribed to alleviate symptoms and delay disease progression in these and sometimes in other forms of dementia. There are uncertainties about the benefits and adverse effects of these drugs in the long term and in severe dementia, about effects of withdrawal, and about the most appropriate time to discontinue treatment.

OBJECTIVES

To evaluate the effects of withdrawal or continuation of cholinesterase inhibitors or memantine, or both, in people with dementia on: cognitive, neuropsychiatric and functional outcomes, rates of institutionalisation, adverse events, dropout from trials, mortality, quality of life and carer-related outcomes.

SEARCH METHODS

We searched the Cochrane Dementia and Cognitive Improvement Group's Specialised Register up to 17 October 2020 using terms appropriate for the retrieval of studies of cholinesterase inhibitors or memantine. The Specialised Register contains records of clinical trials identified from monthly searches of a number of major healthcare databases, numerous trial registries and grey literature sources.

SELECTION CRITERIA

We included all randomised, controlled clinical trials (RCTs) which compared withdrawal of cholinesterase inhibitors or memantine, or both, with continuation of the same drug or drugs.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed citations and full-text articles for inclusion, extracted data from included trials and assessed risk of bias using the Cochrane risk of bias tool. Where trials were sufficiently similar, we pooled data for outcomes in the short term (up to 2 months after randomisation), medium term (3-11 months) and long term (12 months or more). We assessed the overall certainty of the evidence for each outcome using GRADE methods.

MAIN RESULTS

We included six trials investigating cholinesterase inhibitor withdrawal, and one trial investigating withdrawal of either donepezil or memantine. No trials assessed withdrawal of memantine only. Drugs were withdrawn abruptly in five trials and stepwise in two trials. All participants had dementia due to Alzheimer's disease, with severities ranging from mild to very severe, and were taking cholinesterase inhibitors without known adverse effects at baseline. The included trials randomised 759 participants to treatment groups relevant to this review. Study duration ranged from 6 weeks to 12 months. There were too few included studies to allow planned subgroup analyses. We considered some studies to be at unclear or high risk of selection, performance, detection, attrition or reporting bias. Compared to continuing cholinesterase inhibitors, discontinuing treatment may be associated with worse cognitive function in the short term (standardised mean difference (SMD) -0.42, 95% confidence interval (CI) -0.64 to -0.21; 4 studies; low certainty), but the effect in the medium term is very uncertain (SMD -0.40, 95% CI -0.87 to 0.07; 3 studies; very low certainty). In a sensitivity analysis omitting data from a study which only included participants who had shown a relatively poor prior response to donepezil, inconsistency was reduced and we found that cognitive function may be worse in the discontinuation group in the medium term (SMD -0.62; 95% CI -0.94 to -0.31). Data from one longer-term study suggest that discontinuing a cholinesterase inhibitor is probably associated with worse cognitive function at 12 months (mean difference (MD) -2.09 Standardised Mini-Mental State Examination (SMMSE) points, 95% CI -3.43 to -0.75; moderate certainty). Discontinuation may make little or no difference to functional status in the short term (SMD -0.25, 95% CI -0.54 to 0.04; 2 studies; low certainty), and its effect in the medium term is uncertain (SMD -0.38, 95% CI -0.74 to -0.01; 2 studies; very low certainty). After 12 months, discontinuing a cholinesterase inhibitor probably results in greater functional impairment than continuing treatment (MD -3.38 Bristol Activities of Daily Living Scale (BADLS) points, 95% CI -6.67 to -0.10; one study; moderate certainty). Discontinuation may be associated with a worsening of neuropsychiatric symptoms over the short term and medium term, although we cannot exclude a minimal effect (SMD - 0.48, 95% CI -0.82 to -0.13; 2 studies; low certainty; and SMD -0.27, 95% CI -0.47 to -0.08; 3 studies; low certainty, respectively). Data from one study suggest that discontinuing a cholinesterase inhibitor may result in little to no change in neuropsychiatric status at 12 months (MD -0.87 Neuropsychiatric Inventory (NPI) points; 95% CI -8.42 to 6.68; moderate certainty). We found no clear evidence of an effect of discontinuation on dropout due to lack of medication efficacy or deterioration in overall medical condition (odds ratio (OR) 1.53, 95% CI 0.84 to 2.76; 4 studies; low certainty), on number of adverse events (OR 0.85, 95% CI 0.57 to 1.27; 4 studies; low certainty) or serious adverse events (OR 0.80, 95% CI 0.46 to 1.39; 4 studies; low certainty), and on mortality (OR 0.75, 95% CI 0.36 to 1.55; 5 studies; low certainty). Institutionalisation was reported in one trial, but it was not possible to extract data for the groups relevant to this review.

AUTHORS' CONCLUSIONS

This review suggests that discontinuing cholinesterase inhibitors may result in worse cognitive, neuropsychiatric and functional status than continuing treatment, although this is supported by limited evidence, almost all of low or very low certainty. As all participants had dementia due to Alzheimer's disease, our findings are not transferable to other dementia types. We were unable to determine whether the effects of discontinuing cholinesterase inhibitors differed with baseline dementia severity. There is currently no evidence to guide decisions about discontinuing memantine. There is a need for further well-designed RCTs, across a range of dementia severities and settings. We are aware of two ongoing registered trials. In making decisions about discontinuing these drugs, clinicians should exercise caution, considering the evidence from existing trials along with other factors important to patients and their carers.

Discontinuation Rate of Newly Prescribed Donepezil in Alzheimer's Disease Patients in Asia

Background and Purpose

The rate of donepezil discontinuation and the underlying reasons for discontinuation in Asian patients with Alzheimer's disease (AD) are currently unknown. We aimed to determine the treatment discontinuation rates in AD patients who had newly been prescribed donepezil in routine clinical practice in Asia.

Methods

This 1-year observational study involved 38 institutions in seven Asian countries, and it evaluated 398 participants aged 50–90 years with a diagnosis of probable AD and on newly prescribed donepezil monotherapy. The primary endpoint was the rate of donepezil discontinuation over 1 year. Secondary endpoints included the reason for discontinuation, treatment duration, changes in cognitive function over the 1-year study period, and compliance as assessed using a clinician rating scale (CRS) and visual analog scale (VAS).

Results

Donepezil was discontinued in 83 (20.9%) patients, most commonly due to an adverse event (43.4%). The mean treatment duration was 103.67 days in patients who discontinued. Among patients whose cognitive function was assessed at baseline and 1 year, there were no significant changes in scores on the Mini-Mental State Examination, Montreal Cognitive Assessment, and Trail-Making Test–Black and White scores, whereas the Clinical Dementia Rating score increased significantly (p<0.001). Treatment compliance at 1 year was 96.8% (306/316) on the CRS and 92.6±14.1% (mean±standard deviation) on the VAS.

Conclusions

In patients on newly prescribed donepezil, the primary reason for discontinuation was an adverse event. Cognitive assessments revealed no significant worsening at 1 year, indicating that continuous donepezil treatment contributes to the maintenance of cognitive function.

Evaluation and clinical comparison studies on liposomal and non-liposomal ascorbic acid (vitamin C) and their enhanced bioavailability

The aim of this study was to evaluate the oral bioavailability of liposomal vitamin C and non-liposomal vitamin C in healthy, adult, human subjects under fasting conditions through an open label, randomized, single-dose, two-treatment, two-sequence, two-period, two-way crossover, study. The vitamin C loaded liposome was well characterized using transmission electron microscopy (TEM), dynamic light scattering (DLS) and zeta potential measurements for evaluating morphology, particle size and stabilities, respectively. Microscopic image shows the core-type structure that confirms the characteristic pattern of liposome. The encapsulation efficiency (EE%) and the particle size were 65.85 ± 1.84% and below 100 nm, respectively. The results of the clinical studies of liposomal vitamin C by oral delivery to be 1.77 times more bioavailable than non-liposomal vitamin C. The liposomal vitamin C demonstrated higher values of C_max, AUC_0-t and AUC_0-∞ related to non-liposomal vitamin C due to liposomal encapsulation. No adverse events were reported. It could be concluded that liposomal encapsulated ascorbic acid (vitamin C) shows well-organized morphological pattern, uniform particle size and highly efficient, which leads to have enhanced bioavailability.

Are cytochrome P4502D6 and apolipoprotein E genotypes associated with long-term cognitive and functional changes in patients treated with donepezil?

AIM

We investigated the associations of the single-nucleotide polymorphism rs1080985 of cytochrome P4502D6 (CYP2D6) and the apolipoprotein E (APOE) genotypes with cognitive and functional changes in patients treated with donepezil.

METHODS

Sixty-five outpatients with Alzheimer's disease or mixed dementia being treated with donepezil were assessed at baseline and over 27 months. Changes in cognitive status, assessed with the Mini-Mental State Examination, and in functional status, assessed by the Activities of Daily Living Scale and the Instrumental Activities of Daily Living Scale, were evaluated as a function of CYP2D6 and APOE genotypes by using linear mixed models. Multiplicative interactions between the CYP2D6 and APOE genotypes and time were investigated.

RESULTS

Individuals with the mutated CYP2D6 exhibited a slower decline in total Mini-Mental State Examination scores, orientation, registration, and functional status than those with the wild type. A significant interaction between CYP2D6, APOE, and time was found for changes in the Activities of Daily Living Scale; among the ε4 carriers, those with the mutated CYP2D6 exhibited a slower decline on the Activities of Daily Living Scale than those with the wild type.

CONCLUSION

The CYP2D6 and APOE genotypes may modulate the effectiveness of donepezil on cognitive and functional status.

Dysfunction of the Blood-Brain Barrier-A Key Step in Neurodegeneration and Dementia

The vascular endothelium in the brain is an essential part of the blood-brain-barrier (BBB) because of its very tight structure to secure a functional and molecular separation of the brain from the rest of the body and to protect neurons from pathogens and toxins. Impaired transport of metabolites across the BBB due to its increasing dysfunction affects brain health and cognitive functioning, thus providing a starting point of neurodegenerative diseases. The term “cerebral metabolic syndrome” is proposed to highlight the importance of lifestyle factors in neurodegeneration and to describe the impact of increasing BBB dysfunction on neurodegeneration and dementia, especially in elderly patients. If untreated, the cerebral metabolic syndrome may evolve into dementia. Due to the high energy demand of the brain, impaired glucose transport across the BBB via glucose transporters as GLUT1 renders the brain increasingly susceptible to neurodegeneration. Apoptotic processes are further supported by the lack of essential metabolites of the phosphocholine synthesis. In Alzheimer’s disease (AD), inflammatory and infectious processes at the BBB increase the dysfunction and might be pace-making events. At this point, the potentially highly relevant role of the thrombocytic amyloid precursor protein (APP) in endothelial inflammation of the BBB is discussed. Chronic inflammatory processes of the BBB transmitted to an increasing number of brain areas might cause a lasting build-up of spreading, pore-forming β-amyloid fragments explaining the dramatic progression of the disease. In the view of the essential requirement of an early diagnosis to investigate and implement causal therapeutic strategies against dementia, brain imaging methods are of great importance. Therefore, status and opportunities in the field of diagnostic imaging of the living human brain will be portrayed, comprising diverse techniques such as positron emissions tomography (PET) and functional magnetic resonance imaging (fMRI) to uncover the patterns of atrophy, protein deposits, hypometabolism, and molecular as well as functional alterations in AD.

Treatment of Alzheimer's diseases using donepezil nanoemulsion: an intranasal approach

Alzheimer disease (AD) is very common among the older people. There are few medications available as oral and suspension dosage forms for the management of AD. Due to the rising cases of AD and the associated risks of the existing line of treatment, oil in water (o/w) nanoemulsion (NE) loaded with donepezil was prepared to explore intranasal route of administration. The NE was prepared using labrasol (10%), cetyl pyridinium chloride (1% in 80% water), and glycerol (10%), with a drug concentration of 1 mg/ml. The developed NE was characterized for particle size, polydispersity index (PDI), and zeta potential. In vitro release studies were conducted to observe the release of drug. Further in vivo studies of developed NE were done on Sprague Dawley rats using technetium pertechnetate (^99mTc) labeled formulations to investigate the nose to brain drug delivery pathway. The nanoemulsion showed particle size of 65.36 nm with a PDI of 0.084 and zeta potential of -10.7 mV. In vitro release studies showed maximum release of 99.22% in 4 h in phosphate-buffered saline, 98% in 2 h in artificial cerebrospinal fluid, and 96% in 2 h in simulated nasal fluid. The cytotoxicity and antioxidant activity of the NE showed dose-dependent cytotoxicity and % radical scavenging activity (%RSA). The images of giemsa staining also confirmed that the developed formulation has no impact on the morphology of cells. Scintigrams showed maximum uptake of NE in the brain. The findings suggested that the developed NE loaded with donepezil hydrochloride could serve as a new approach for the treatment of Alzheimer via nose to brain drug delivery. Graphical abstract.

mGluR5 Contribution to Neuropathology in Alzheimer Mice Is Disease Stage-Dependent

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease and is characterized by a progressive cognitive decline in affected individuals. Current therapeutic strategies are limited in their efficacy and some have proven to be even less effective at later disease stages or after extended use. We previously demonstrated that chronic inhibition of mGluR5 signaling using the selective negative allosteric modulator (NAM) CTEP in APPswe/PS1ΔE9 mice can rescue cognitive function, activating the ZBTB16-mediated autophagy pathway to reduce Aβ, the principal neurotoxic species in AD brains. Here, we evaluated the efficacy of long-term treatment with CTEP in 6 month old APPswe/PS1ΔE9 mice for either 24 or 36 weeks. CTEP maintained its efficacy in reversing working and spatial memory deficits and mitigating neurogliosis in APPswe/PS1ΔE9 mice when administered for 24 weeks. This was paralleled by a significant reduction in Aβ oligomer and plaque load as a result of autophagy activation via ZBTB16 and mTOR-dependent pathways. However, further extension of CTEP treatment for 36 weeks was found ineffective in reversing memory deficit, neurogliosis, or Aβ-related pathology. We found that this loss in CTEP efficacy in 15 month old APPswe/PS1ΔE9 mice was due to the abolished contribution of ZBTB16 and mTOR-mediated signaling to AD neuropathology at this advanced disease stage. Our findings indicate that the contribution of pathological mGluR5-signaling to AD may shift as the disease progresses. Thus, we provide the first evidence that the underlying pathophysiological mechanism(s) of AD may unfold along the course of the disease and treatment strategies should be modified accordingly to ensure maximal therapeutic outcomes.

Do nonpharmacological interventions prevent cognitive decline? a systematic review and meta-analysis

At present, prevention is particularly important when there is no effective treatment for cognitive decline. Since the adverse events of pharmacological interventions counterbalance the benefits, nonpharmacological approaches seem desirable to prevent cognitive decline. To our knowledge, no meta-analyses have been published on nonpharmacological interventions preventing cognitive decline. To investigate whether nonpharmacological interventions play a role in preventing cognitive decline among older people, we searched related trials up to March 31, 2019, in MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ClinicalTrials and the Cochrane library databases. Randomized controlled trials (RCTs) were included if they enrolled participants older than 60 years of age who had a risk of cognitive decline, and the interventions were nonpharmacological. Two reviewers independently extracted data and assessed study quality. The Grading of Recommendations Assessment Development and Evaluation (GRADE) approach was used to rate the quality of evidence. Heterogeneity was quantified with I2. Subgroup analysis and meta-regression were used to research the sources of heterogeneity. Influence analyses were used to detect and remove extreme effect sizes (outliers) in our meta-analysis. Publication bias was assessed with funnel plots and Egger test. Primary outcomes were the incidence of mild cognitive impairment (MCI) or dementia and Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog) scores. Second outcomes were activities of daily living (ADL) and Mini-Mental State Examination (MMSE) scores. A total of 22 studies with 13,264 participants were identified for analysis. In terms of prevention, nonpharmacological interventions appeared to be more effective than control conditions, as assessed by the incidence of MCI or dementia (RR, 0.73; CI, 0.55-0.96; moderate-certainty evidence), while the results of ADAS-Cog suggested no significant differences between two groups (MD, -0.69; CI, -1.52-0.14; very low-certainty evidence). Second outcomes revealed a significant improvement from nonpharmacological interventions versus control in terms of the change in ADL (MD, 0.73; CI, 0.65-0.80) and MMSE scores (posttreatment scores: MD, 0.25; CI, 0.02-0.47; difference scores: MD, 0.59, CI, 0.29-0.88). Univariable meta-regression showed association between lower case of MCI or dementia and two subgroup factors (P = 0.013 for sample size; P = 0.037 for area). Multiple meta-regression suggested that these four subgroup factors were not associated with decreased incidence of MCI (P > 0.05 for interaction). The Naive RR estimate was calculated as 0.73. When the three studies that detected by outlier and influence analysis were left out, the Robust RR was 0.66. In conclusion, nonpharmacological therapy could have an indicative role in reducing the case of MCI or dementia. However, given the heterogeneity of the included RCTs, more preregistered trials are needed that explicitly examine the association between nonpharmacological therapy and cognitive decline prevention, and consider relevant moderators.

Alzheimer's Disease Therapeutic Approaches

Alzheimer's disease (AD) was first described and diagnosed by Dr. Alois Alzheimer in 1906 (Hippius and Neundorfer, Dialogues Clin Neurosc 5:101-108, 2003). According to World Health Organization (WHO), AD is the most common cause of dementia, accounting for as many as 60-70% of senile dementia cases and affecting 47.5 million people worldwide (data from 2015) (Dementia Fact Sheet No 362. http://who.int/mediacentre/factsheets/fs362/en/ ). The median survival time after the onset of dementia ranges from 3.3 to 11.7 years (Todd et al. Int J Geriatr Psychiatry 28:1109-1124, 2013). AD is characterized as a severe, chronic, incurable, and progressive neurodegenerative disorder, associated with memory loss and cognition impairment accompanied by abnormal behavior and personality changes (Godyn et al. Pharmacol Rep 68:127-138, 2016). AD is characterized by neuronal death, which usually correlates with the appearance of key neuropathological changes, including acetylcholine deficiency, glutamate excitotoxicity, extracellular deposition of β-amyloid (Aβ plaques), intracellular neurofibrillary tangles by hyperphosphorylated tau protein deposits, neuroinflammation, and widespread neuronal loss (Godyn et al. Pharmacol Rep 68:127-138, 2016; Graham et al. Annu Rev. Med 68:413-430, 2017). The discovery of the degeneration of cholinergic neurons and the reduction of acetylcholine levels in postmortem studies of patients resulted in the use of drugs that leads to the increase of acetylcholine levels in brain (Dubois et al. Lacet Neurol 13:614-629, 2014). At present there is no preventative or curative treatment that interferes with the development of the disease. However, in recent years progress was made in the development of cholinergic drugs which have a positive effect on disease progression. Nowadays, specific drugs that can inhibit the enzyme that degrades acetylcholine are used. The development of new effective drugs involves a difficult and time-consuming process, accompanied by a very high failure rate. In the absence of effective therapies, the estimated number of people with dementia will reach 115 to 131, five million by 2050 (Dubois et al. Lacet Neurol 13:614-629, 2014; Cummings et al. Alzheimers Res Ther 6:37, 2014). Novel therapies and new targets required for developing more effective drugs for the treatment of AD patients are urgently needed.

Clinical efficacy and safety of donepezil in the treatment of Alzheimer's disease in Chinese patients

Donepezil, an acetylcholinesterase inhibitor (AChEI), has been widely used to treat Alzheimer's disease (AD) in China. However, there are few studies focusing on the efficacy and safety of donepezil in Chinese patients. In this review, we discuss 1) the efficacy of donepezil and its comparison with other AChEIs or memantine, 2) the therapeutic responses to donepezil and its influencing factors, and 3) the safety and tolerability of donepezil in Chinese patients with different stages of AD and amnestic mild cognitive impairment, and further compare the similarities and differences of the results between Chinese studies and previous Western studies that predominantly enrolled Caucasian subjects. We include Chinese clinical trials and other well-designed studies investigating donepezil or using donepezil as a positive control, in which the efficacy and/or safety of donepezil have been analyzed. Based on these studies, donepezil has been shown to be effective and safe in Chinese AD patients and may impact AD biomarkers, such as hippocampal atrophy, Aβ, and tau. In addition, the therapeutic response to donepezil may be influenced by apolipoprotein E or cytochrome P450 2D6 polymorphism.

Disrupted topology of the resting state structural connectome in middle-aged APOE ε4 carriers

The apolipoprotein E (APOE) ε4 allele is the best characterized genetic risk factor for Alzheimer's disease to date. Older APOE ε4 carriers (aged 60 + years) are known to have disrupted structural and functional connectivity, but less is known about APOE-associated network integrity in middle age. The goal of this study was to characterize APOE-related differences in network topology in middle age, as disentangling the early effects of healthy versus pathological aging may aid early detection of Alzheimer's disease and inform treatments. We performed resting state functional magnetic resonance imaging (rs-fMRI) and diffusion tensor imaging (DTI) in healthy, cognitively normal, middle-aged adults (age 40-60; N = 76, 38 APOE ε4 carriers). Graph theoretical analysis was used to calculate local and global efficiency of 1) a whole brain rs-fMRI network; 2) a whole brain DTI network; and 3) the resting state structural connectome (rsSC), an integrated functional-structural network derived using functional-by-structural hierarchical (FSH) mapping. Our results indicated no APOE ε4-associated differences in network topology of the rs-fMRI or DTI networks alone. However, ε4 carriers had significantly lower global and local efficiency of the integrated rsSC compared to non-carriers. Furthermore, ε4 carriers were less resilient to targeted node failure of the rsSC, which mimics the neuropathological process of Alzheimer's disease. Collectively, these findings suggest that integrating multiple neuroimaging modalities and employing graph theoretical analysis may reveal network-level vulnerabilities that may serve as biomarkers of age-related cognitive decline in middle age, decades before the onset of overt cognitive impairment.

Donepezil for dementia due to Alzheimer's disease

BACKGROUND

Alzheimer's disease is the most common cause of dementia in older people. One approach to symptomatic treatment of Alzheimer's disease is to enhance cholinergic neurotransmission in the brain by blocking the action of the enzyme responsible for the breakdown of the neurotransmitter acetylcholine. This can be done by a group of drugs known as cholinesterase inhibitors. Donepezil is a cholinesterase inhibitor.This review is an updated version of a review first published in 1998.

OBJECTIVES

To assess the clinical efficacy and safety of donepezil in people with mild, moderate or severe dementia due to Alzheimer's disease; to compare the efficacy and safety of different doses of donepezil; and to assess the effect of donepezil on healthcare resource use and costs.

SEARCH METHODS

We searched Cochrane Dementia and Cognitive Improvement's Specialized Register, MEDLINE, Embase, PsycINFO and a number of other sources on 20 May 2017 to ensure that the search was as comprehensive and up-to-date as possible. In addition, we contacted members of the Donepezil Study Group and Eisai Inc.

SELECTION CRITERIA

We included all double-blind, randomised controlled trials in which treatment with donepezil was administered to people with mild, moderate or severe dementia due to Alzheimer's disease for 12 weeks or more and its effects compared with those of placebo in a parallel group of patients, or where two different doses of donepezil were compared.

DATA COLLECTION AND ANALYSIS

One reviewer (JSB) extracted data on cognitive function, activities of daily living, behavioural symptoms, global clinical state, quality of life, adverse events, deaths and healthcare resource costs. Where appropriate and possible, we estimated pooled treatment effects. We used GRADE methods to assess the quality of the evidence for each outcome.

MAIN RESULTS

Thirty studies involving 8257 participants met the inclusion criteria of the review, of which 28 studies reported results in sufficient detail for the meta-analyses. Most studies were of six months' duration or less. Only one small trial lasted 52 weeks. The studies tested mainly donepezil capsules at a dose of 5 mg/day or 10 mg/day. Two studies tested a slow-release oral formulation that delivered 23 mg/day. Participants in 21 studies had mild to moderate disease, in five studies moderate to severe, and in four severe disease. Seventeen studies were industry funded or sponsored, four studies were funded independently of industry and for nine studies there was no information on source of funding.Our main analysis compared the safety and efficacy of donepezil 10 mg/day with placebo at 24 to 26 weeks of treatment. Thirteen studies contributed data from 3396 participants to this analysis. Eleven of these studies were multicentre studies. Seven studies recruited patients with mild to moderate Alzheimer's disease, two with moderate to severe, and four with severe Alzheimer's disease, with a mean age of about 75 years. Almost all evidence was of moderate quality, downgraded due to study limitations.After 26 weeks of treatment, donepezil compared with placebo was associated with better outcomes for cognitive function measured with the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog, range 0 to 70) (mean difference (MD) -2.67, 95% confidence interval (CI) -3.31 to -2.02, 1130 participants, 5 studies), the Mini-Mental State Examination (MMSE) score (MD 1.05, 95% CI 0.73 to 1.37, 1757 participants, 7 studies) and the Severe Impairment Battery (SIB, range 0 to 100) (MD 5.92, 95% CI 4.53 to 7.31, 1348 participants, 5 studies). Donepezil was also associated with better function measured with the Alzheimer's Disease Cooperative Study activities of daily living score for severe Alzheimer's disease (ADCS-ADL-sev) (MD 1.03, 95% CI 0.21 to 1.85, 733 participants, 3 studies). A higher proportion of participants treated with donepezil experienced improvement on the clinician-rated global impression of change scale (odds ratio (OR) 1.92, 95% CI 1.54 to 2.39, 1674 participants, 6 studies). There was no difference between donepezil and placebo for behavioural symptoms measured by the Neuropsychiatric Inventory (NPI) (MD -1.62, 95% CI -3.43 to 0.19, 1035 participants, 4 studies) or by the Behavioural Pathology in Alzheimer's Disease (BEHAVE-AD) scale (MD 0.4, 95% CI -1.28 to 2.08, 194 participants, 1 study). There was also no difference between donepezil and placebo for Quality of Life (QoL) (MD -2.79, 95% CI -8.15 to 2.56, 815 participants, 2 studies).Participants receiving donepezil were more likely to withdraw from the studies before the end of treatment (24% versus 20%, OR 1.25, 95% CI 1.05 to 1.50, 2846 participants, 12 studies) or to experience an adverse event during the studies (72% vs 65%, OR 1.59, 95% 1.31 to 1.95, 2500 participants, 10 studies).There was no evidence of a difference between donepezil and placebo for patient total healthcare resource utilisation.Three studies compared donepezil 10 mg/day to donepezil 5 mg/day over 26 weeks. The 5 mg dose was associated with slightly worse cognitive function on the ADAS-Cog, but not on the MMSE or SIB, with slightly better QoL and with fewer adverse events and withdrawals from treatment. Two studies compared donepezil 10 mg/day to donepezil 23 mg/day. There were no differences on efficacy outcomes, but fewer participants on 10 mg/day experienced adverse events or withdrew from treatment.

AUTHORS' CONCLUSIONS

There is moderate-quality evidence that people with mild, moderate or severe dementia due to Alzheimer's disease treated for periods of 12 or 24 weeks with donepezil experience small benefits in cognitive function, activities of daily living and clinician-rated global clinical state. There is some evidence that use of donepezil is neither more nor less expensive compared with placebo when assessing total healthcare resource costs. Benefits on 23 mg/day were no greater than on 10 mg/day, and benefits on the 10 mg/day dose were marginally larger than on the 5 mg/day dose, but the rates of withdrawal and of adverse events before end of treatment were higher the higher the dose.

Cardiovascular monitoring with acetylcholinesterase inhibitors: a clinical protocol

There has been significant anxiety among prescribers regarding the potential for cardiac adverse effects associated with acetylcholinesterase (AChE) inhibitors in Alzheimer's disease. There is no consensus on how to manage this cardiovascular risk, and memory clinics vary widely in their practice. Review of published evidence reveals that the incidence of cardiovascular side-effects is low, and that serious adverse events are rare. Intensive cardiovascular screening such as pre-treatment electrocardiograms or 24 h cardiac monitoring is not justified. Furthermore, there are no high-risk groups to target. This article suggests pragmatic guidelines for managing cardiovascular risk in patients receiving AChE inhibitors. The guidelines are intended to be easy to incorporate into routine clinical practice in a memory clinic.

WITHDRAWN: Revisiting the cholinergic hypothesis in Alzheimer's disease: Emerging evidence from translational and clinical research

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Cocaine cardiovascular effects and pharmacokinetics after treatment with the acetylcholinesterase inhibitor donepezil

BACKGROUND

In rodents, cholinesterase inhibitors can cause sustained decreases in the reinforcing effects of cocaine. Nonetheless, cocaine is metabolized by butyrylcholinesterase (BuChE), raising concerns that cholinesterase inhibition could increase its peripheral concentrations, perhaps augmenting toxicity. Although donepezil is approved for use in patients and selective for inhibiting acetylcholinesterase over BuChE, no studies have reported cocaine bioavailability in human subjects receiving donepezil.

METHODS

Twelve cocaine-dependent veterans received three days of treatment with either oral placebo or 5 mg daily of donepezil, followed by cross-over to the opposite treatment. During both oral treatments, double-blind intravenous cocaine was administered at .0, .18, and .36 mg/kg in a laboratory setting, followed by determinations of heart rate, blood pressure, and plasma concentrations of cocaine and major metabolites.

RESULTS

Intravenous cocaine produced dose-related increases in systolic blood pressure that were most pronounced over the initial 30 minutes after treatment. Oral donepezil attenuated drug-induced elevations of systolic blood pressure following low-dose cocaine (.18 mg/kg). No significant difference in blood pressure following treatment with placebo or donepezil after high-dose cocaine (.36 mg/kg). Peak values of blood pressure and heart rate were unaffected by donepezil. Plasma concentrations of cocaine and metabolites did not differ in donepezil- and placebo-treated participants.

CONCLUSIONS AND SCIENTIFIC SIGNIFICANCE

We conclude that donepezil can attenuate drug-induced increases in systolic blood pressure following low-dose cocaine, but does not otherwise modify the cardiovascular effects of intravenous cocaine. Clinically significant changes in cocaine bioavailability and cardiovascular effects do not occur following this dose of donepezil. (Am J Addict 2016;25:392-399).

Cholinergic enhancement increases regional cerebral blood flow to the posterior cingulate cortex in mild Alzheimer's disease

AIM

The brain region that shows reductions in regional cerebral blood flow (rCBF) earliest is the posterior cingulate cortex (PCC), which is thought to have a relationship with cognitive function. We made a hypothesis that the PCC hypoperfusion is a result of cholinergic dysfunction and can be restored by cholinergic enhancement. This present longitudinal study aimed to detect the restoration of PCC rCBF in response to donepezil, an acetylcholine esterase inhibitor.

METHODS

We evaluated rCBF changes in the PCC, precuneus and anterior cingulate cortex using perfusion single-photon emission computed tomography (SPECT), statistical analysis and region of interest analysis, prospectively. We allocated 36 patients with mild AD to either the responder or non-responder groups based on changes in Mini-Mental State Examination scores. The patients were followed up for 18 months.

RESULTS

The PCC rCBF significantly increased in responders after 6 months of donepezil therapy. Statistical maps at baseline showed a typical decreased pattern of mild AD and obvious rCBF restoration in the bilateral PCC at 6 months in responders. Changes in Mini-Mental State Examination scores and the AD assessment scale cognitive scores significantly correlated with rCBF changes in the PCC of responders.

CONCLUSIONS

Cholinergic enhancement restored PCC rCBF under the three conditions of mild AD, responders and short follow-up interval, and that increase correlated with improved cognitive function. These findings support our hypothesis that PCC rCBF reflects cholinergic function in AD patients. Geriatr Gerontol Int 2017; 17: 951-958.

Pharmacological management of behavioral and psychiatric symptoms in older adults with intellectual disability

Given medical and social advances, the life expectancy of individuals with intellectual disability (ID) has increased dramatically, leading to a generation of older individuals with such disabilities. This review focuses on the pharmacological treatment of behavioral and psychiatric symptoms and disorders in older adults with ID. Older adults with ID often present with medical co-morbidities and mental health issues. Medication management of behavioral and psychiatric problems is complicated by a higher risk for adverse events, lack of decision-making capacity, and complex care networks. Some studies have shown that individuals with ID and co-morbid mental disorders are undertreated in comparison with those with similar disorders in the general population, resulting in poorer outcomes. However, older adults with ID are also at risk of polypharmacy, and older age is a risk factor for development of side effects. A general principle is that medication treatment for psychiatric disorders in older individuals with ID should be started at low dosages and increased cautiously while monitoring response and side effects. The use of psychotropic drugs for older individuals with ID and behavioral problems remains controversial, particularly in those with dementia.

Predictors of Response to Cholinesterase Inhibitors Treatment of Alzheimer's Disease: Date Mining from the TREDEM Registry

BACKGROUND

The pharmacological treatment of Alzheimer's disease (AD) is based largely on cholinesterase inhibitors (ChEI).

OBJECTIVE

To investigate whether or not some non-pharmacological and contextual factors measured prior to starting treatment such as past occupation, lifestyles, marital status, degree of autonomy and cognitive impairment, living alone or with others, and the degree of brain atrophy are associated with a better response to ChEI treatment.

METHODS

Eighty-four AD and six AD with cerebrovascular disease (AD + CVD) outpatients of Treviso Dementia (TREDEM) Registry, with an average cholinesterase inhibitors treatment length of four years, were considered. The outpatients had undergone a complete evaluation and some non-pharmacological and contextual factors were collected. We defined responder a patient with a delta score T0 - T1 equal or inferior to 2.0 points per year of MMSE and a non-responder a patient with a delta score T0 - T1 superior to 2.0 points per year. In order to identify hidden relationships between variables related to response and non-response, we use a special kind of artificial neural network called Auto-CM, able to create a semantic connectivity map of the variables considered in the study.

RESULTS

A higher cognitive profile, a previous intellectual occupation, healthier lifestyles, being married and not living alone, a higher degree of autonomy, and lower degree of brain atrophy at baseline resulted in affecting the response to long-term ChEI therapy.

CONCLUSION

Non-pharmacological and contextual factors appear to influence the effectiveness of treatment with ChEI in the long term.

Donepezil Regulates 1-Methyl-4-phenylpyridinium-Induced Microglial Polarization in Parkinson's Disease

1-Methyl-4-phenylpyridinium (MPP+) induces microglial activation and degeneration of dopaminergic (DAergic) neurons. Donepezil is a well-known acetylcholinesterase inhibitor used clinically to treat cognitive dysfunction in Alzheimer's disease (AD). In the present study, we tested the hypothesis that MPP+ promotes microglial M1 polarization and suppresses M2 polarization and that this can be restored by donepezil. Results indicate that MPP+ treatment in microglial BV2 cells promotes microglial polarization toward the M1 state. However, pretreatment with donepezil inhibited MPP+-induced M1 polarization in microglia by suppressing the release of interleukin (IL)-6, IL-1β, or tumor necrosis factor (TNF)-α. Importantly, we found that MPP+ inhibited microglial M2 polarization by suppressing expression of Arg-1, Fizz1, and Ym1, which was also rescued by pretreatment with donepezil. In addition, IL-4-mediated induction of anti-inflammatory marker genes IL-10, IL-13, and transforming growth factor-β2 (TGF-β2) were significantly attenuated by MPP+ in BV2 cells, which was restored by pretreatment with donepezil in a concentration-dependent manner. Mechanistically, we found that the addition of MPP+ reduced the intensity of phosphorylated signal transducer and activator of transcription 6 (STAT6) but not total STAT6 in IL-4-stimulated BV2 cells. Importantly, pretreatment of microglial BV2 cells with donepezil 3 h prior to administration of MPP+ rescued the reduction of STAT6 phosphorylation induced by MPP+.

Current Practices in the Treatment of Alzheimer Disease: Where is the Evidence After the Phase III Trials?

PURPOSE

The purpose of this systematic review was to review the current place in therapy of the 4 medications, donepezil, rivastigmine, galantamine, and memantine, approved for the treatment of Alzheimer disease (AD) since the publication of Phase III trials.

METHODS

A systematic literature search of MEDLINE and EMBASE was conducted for articles published in the past 10 years. The search was performed using the following Medical Subject Headings and text key words: Alzheimer's disease, treatment, donepezil, galantamine, rivastigmine, memantine, dementia of the Alzheimer's type, and dementia.

FINDINGS

Studies that evaluated new doses, indications, and dose formulations remain a large part of the current literature. Donepezil gained approval for the treatment of severe AD and became available in a 23-mg/d dose formulation. Rivastigmine became available in a patch formulation. Memantine became available as an extended-release capsule. Use of a combination product formulation was recently approved, memantine extended release/donepezil. Controversy among clinicians remains regarding when to initiate therapy, appropriate duration of therapy, and how and when to discontinue the treatment of AD.

IMPLICATIONS

Only drugs that affect cholinergic function have shown consistent, but modest, clinical effects, even in late-phase trials. There is a need for a better appreciation of the various risk factors and drug targets for the treatment of AD. The wide range of targets makes it unlikely that affecting only 1 of those targets (eg, cholinergic function or N-methyl-d-aspartate) will lead to a more than minimally effective treatment option, regardless of when a treatment is started and discontinued. There is substantial opportunity for the continued growth and development of drugs and clinical trial expansion for the treatment of AD.

The influence of cholinesterase inhibitor therapy for dementia on risk of cardiac pacemaker insertion: a retrospective, population-based, health administrative databases study in Ontario, Canada

BACKGROUND

Cholinesterase inhibitors are used to treat the symptoms of dementia and can theoretically cause bradycardia. Previous studies suggest that patients taking these medications have an increased risk of undergoing pacemaker insertion. Since these drugs have a marginal impact on patient outcomes, it might be preferable to change drug treatment rather than implant a pacemaker. This population-based study determined the association of people with dementia exposed to cholinesterase inhibitor medication and pacemaker insertion.

METHODS

We used data from the Ontario health administrative databases from January 1, 1993 to June 30, 2012. We included all community-dwelling seniors who had a code for dementia and were exposed to cholinesterase inhibitors (donezepil, galantamine, and rivastigmine) and/or drugs used to treat co-morbidities of hypertension, diabetes, depression and hypothyroidism. We controlled for exposure to anti-arrhythmic drugs. Observation started at first exposure to any medication and continued until the earliest of pacemaker insertion, death, or end of study.

RESULTS

2,353,909 people were included with 96,000 (4.1%) undergoing pacemaker insertion during the observation period. Case-control analysis showed that pacemaker patients were less likely to be coded with dementia (unadjusted OR 0.42 [95%CI 0.41-0.42]) or exposed to cholinesterase inhibitors (unadjusted OR 0.39 [95%CI 0.37-0.41]). That Cohort analysis showed patients with dementia taking cholinesterase inhibitors had a decreased risk of pacemaker insertion (unadj-HR 0.58 [0.55-0.61]). Adjustment for patient age, sex, and other medications did not notably change results, as did restricting the analysis to incident users.

CONCLUSIONS

Patients taking cholinesterase inhibitors rarely undergo, and have a significantly reduced risk of, cardiac pacemaker insertion.

Nicotinic ACh receptors as therapeutic targets in CNS disorders

The neurotransmitter acetylcholine (ACh) can regulate neuronal excitability by acting on the cys-loop cation-conducting ligand-gated nicotinic ACh receptor (nAChR) channels. These receptors are widely distributed throughout the central nervous system (CNS), being expressed on neurons and non-neuronal cells, where they participate in a variety of physiological responses such as anxiety, the central processing of pain, food intake, nicotine seeking behavior, and cognitive functions. In the mammalian brain, nine different subunits have been found thus far, which assemble into pentameric complexes with much subunit diversity; however, the α7 and α4β2 subtypes predominate in the CNS. Neuronal nAChR dysfunction is involved in the pathophysiology of many neurological disorders. Here we will briefly discuss the functional makeup and expression of the nAChRs in mammalian brain, and their role as targets in neurodegenerative diseases (in particular Alzheimer's disease, AD), neurodevelopmental disorders (in particular autism and schizophrenia), and neuropathic pain.

Persistence and adherence with dementia pharmacotherapy: relevance of patient, provider, and system factors

This paper provides a comprehensive review of studies examining adherence and (or) persistence with dementia pharmacotherapy during the past decade, including a summary of the key patient-, drug-, system-, and provider-level factors associated with these measures. Estimates of adherence and 1-year persistence to these drugs have ranged from 34% to 94% and 35% to 60%, respectively. Though many studies reported nonsignificant associations, there are data suggesting that patient age, sex, ethnoracial background, socioeconomic status, and region-specific reimbursement criteria, as well as the extent and quality of interactions among patients, caregivers, and providers, may influence persistence with pharmacotherapy. As many studies relied on administrative data, limited information was available regarding the relevance of patient's cognitive and functional status or the importance of caregiver involvement or assistive devices to adherence or persistence.

Factors associated with response to acetylcholinesterase inhibition in dementia: a cohort study from a secondary mental health care case register in london

BACKGROUND

Acetylcholinesterase inhibitors (AChEIs) are widely used to delay cognitive decline in Alzheimer's disease. Observational studies in routine clinical practice have shown cognitive improvement in some groups of patients receiving these agents but longitudinal trajectories before and after AChEI initiation have not previously been considered.

OBJECTIVES

To compare trajectories of cognitive function before and after AChEI initiation and investigate predictors of these differences.

METHOD

A retrospective longitudinal study was constructed using data from 2460 patients who received AChEIs and who had routine data on cognitive function (Mini-Mental State Examination; MMSE) before and after AChEI initiation. Longitudinal MMSE change was modelled using three-piece linear mixed models with the following segments: 0-12 months prior to AChEI initiation, 0-6 months and 6-36 months after initiation.

RESULTS

MMSE decline was reversed (in that the slope was improved by an average 4.2 units per year, 95% CI 3.5-4.8) during the 6-month period following AChEI initiation compared with the slope in the one year period before AChEI initiation. The slope in the period from 6-36 months following AChEI initiation returned to the pre-initiation downward trajectory. The differences in slopes in the 1 year period prior to AChEI initiation and in the 6 months after initiation were smaller among those with higher MMSE scores at the time of AChEI initiation, among those who received a vascular dementia diagnosis at any point, and among those receiving antipsychotic agents.

CONCLUSION

In this naturalistic observational study, changes in cognitive trajectories around AChEI initiation were similar to those reported in randomised controlled trials. The magnitude of the difference in slopes between the 1 year period prior to AChEI initiation and the 6 month period after AChEI initiation was related to level of cognitive function at treatment initiation, vascular comorbidity and antipsychotic use.

Screening of β-secretase and acetylcholinesterase inhibitors from plant resources

The therapeutic agents for dementia are limited due to the complex system underlying the mechanisms. Taking a preventive point of view, we focused on the inhibition of β-secretase and acetylcholinesterase (AChE). In addition, plant resources including herbs and spices have been widely consumed, and further, may be consumed for a long period over a lifetime. Considering this background, we screened β-secretase and AChE inhibitors from curry spices. Amongst them, curry leaf, black pepper, and turmeric extracts were effective to inhibit β-secretase. Furthermore, black pepper and turmeric extracts were also effective to inhibit AChE. Having these results in hand, we focused on the investigation of β-secretase inhibitors since the inhibitor of this enzyme has not previously been well investigated. As a result, α- and β-caryophyllene, β-caryophyllene oxide (from curry leaf), piperine (from black pepper), curcumin, demethoxycurcumin, and bisdemethoxycurcumin (from turmeric) were successfully identified as low molecular inhibitors. This is the first report to determine α- and β-caryophyllene, β-caryophyllene oxide, and piperine as β-secretase inhibitors. These compounds may pass through the blood brain barrier since their molecular weights are relatively low.

Cholinesterase inhibitors for the treatment of Alzheimer's disease:: getting on and staying on

BACKGROUND

Cholinesterase (ChE) inhibitors currently used in the treatment of Alzheimer's disease (AD) are the acetylcholinesterase (AChE)-selective inhibitors, donepezil and galantamine, and the dual AChE and butyrylcholinesterase (BuChE) inhibitor, rivastigmine. In addition to differences in selectivity for AChE and BuChE, ChE inhibitors also differ in pharmacokinetic and pharmacodynamic properties, and these differences could significantly impact on safety, tolerability, and efficacy.

OBJECTIVE

The aim of this article was to provide an overview of the ChE inhibitors widely used in AD, focusing on key pharmacologic differences among agents and how these may translate into important differences in safety, tolerability, and efficacy in clinical practice.

METHODS

Using published literature collected over time by the author, a review was conducted, focusing on the pharmacology and clinical data of donepezil, galantamine, and rivastigmine.

RESULTS

All ChE inhibitors have the potential to induce centrally mediated cholinergic adverse events (AEs), such as nausea and vomiting, if the dose is increased too rapidly or in increments that are too large. These AEs, which are most likely to occur during the "getting on," or dose-escalation, phase of treatment, may result in patients discontinuing treatment early without achieving optimum therapeutic benefit. To reduce the incidence of these AEs, a slow dose-escalation schedule has been established in clinical practice, consisting of a "start low, go slow" procedure with a minimum of 4 weeks between dose increases. After "getting on" treatment, maintaining treatment in the long term, or "staying on," may be achieved with good safety, tolerability, and sustained symptomatic efficacy across the key symptom domains (activities of daily living, behavior, and cognition).

CONCLUSIONS

ChE inhibitors provide symptomatic benefit in AD across key symptom domains. Factors influencing the safety, tolerability, and efficacy of these agents in clinical practice include ChE enzymes inhibited, brain and brain-region ChE selectivity, and metabolism route. Class-specific cholinergic AEs can be minimized using slow, flexible dose escalation.

Pharmacokinetic and pharmacodynamic evaluation of donepezil for the treatment of Alzheimer's disease

INTRODUCTION

Donepezil is a highly selective acetylcholinesterase inhibitor and one of the only four drugs currently approved for treatment of Alzheimer's dementia. Providing high bioavailability and a very long half-time, donepezil is regarded as effective and well tolerable in Alzheimer's disease patients, even in difficult clinical conditions such as hepatic or renal impairment. It moderately improves cognitive and global functioning scores in patients with mild to moderate Alzheimer's disease over the course of 6 - 12 months, with open-label extension studies suggesting effects of even longer duration.

AREAS COVERED

We summarized relevant pharmacokinetic, pharmacodynamic, clinical trial and neuroimaging data of donepezil. A literature search was performed in the PubMed database; articles published until October 2013 have been considered for this review. Moreover, references from original work and reviews have been searched for further relevant literature.

EXPERT OPINION

Donepezil is one of the most frequently prescribed anti-dementia drugs. The recent additional approval of the 23 mg formulation will expand its use in patients with moderate to severe Alzheimer's disease. After numerous Phase III study failures of novel disease-modifying drugs for Alzheimer's disease, donepezil is likely going to stay a first-line therapeutic option in Alzheimer's disease in the upcoming years.

A rare case of acute renal failure secondary to rhabdomyolysis probably induced by donepezil

Introduction. Acute renal failure (ARF) develops in 33% of the patients with rhabdomyolysis. The main etiologic factors are alcoholism, trauma, exercise overexertion, and drugs. In this report we present a rare case of ARF secondary to probably donepezil-induced rhabdomyolysis. Case Presentation. An 84-year-old male patient was admitted to the emergency department with a complaint of generalized weakness and reduced consciousness for two days. He had a history of Alzheimer's disease for one year and he had taken donepezil 5 mg daily for two months. The patient's physical examination revealed apathy, loss of cooperation, and decreased muscle strength. Laboratory studies revealed the following: urea: 128 mg/dL; Creatinine 6.06 mg/dL; creatine kinase: 3613 mg/dL. Donepezil was discontinued and the patient's renal function tests improved gradually. Conclusion. Rhabdomyolysis-induced acute renal failure may develop secondary to donepezil therapy.

A 2-year prospective cohort study of antidementia drug non-persistency in mild-to-moderate Alzheimer's disease in Europe : predictors of discontinuation and switch in the ICTUS study

BACKGROUND

There is no consensus on when and how to discontinue cholinesterase inhibitors (ChEI). Predictors of non-persistency of antidementia drugs have been poorly investigated, mostly during short-term periods and using administrative data.

OBJECTIVE

The aim of this study was to investigate the incidence and predictors of ChEI switch and discontinuation among subjects with ascertained Alzheimer's disease (AD).

METHODS

A total of 557 community-dwelling, mild-to-moderate AD subjects initiating ChEIs in 29 European clinic centres were assessed twice-yearly for 2 years. Antidementia drug exposure was recorded through a physician-administered structured questionnaire to document any change in drug therapy (start and stop dates, reasons). Discontinuation was defined as >35 days without any antidementia drug. Switch was defined as a change for any antidementia drug strategy within 35 days after ChEI cessation. Two separate time-dependent multivariate Cox survival analyses were conducted to identify predictors of discontinuation and switch.

RESULTS

The incidences of discontinuation and switch were 9.65 and 12.47/100 person-years, respectively. Behavioural disturbances, low body mass index, falls, decline in Mini-Mental State Examination (MMSE) score, and AD-related hospitalization predicted discontinuation. MMSE score, decline in activities of daily living score, aberrant motor behaviour, shorter AD duration and higher nurse resource use predicted a switch. An ineffective ChEI dose and clinic specialty predicted both outcomes. Sensitivity analyses using a 60-day cut-off provided stable results.

CONCLUSION

Several predictors were identified: adverse drug events and their predisposing factors, perceived loss of efficacy or disease progression on cognitive or functional scales, behavioural disturbances, hospitalization and professional practices. The latter implies a need for harmonization in AD drug prescription practice.

Beyond symptomatic therapy: a re-examination of acetylcholinesterase inhibitors in Alzheimer’s disease

Acetylcholinesterase inhibitors (AChEIs) are generally regarded as palliative treatments for Alzheimer's disease that slow the progression of dementia symptoms without altering Alzheimer's disease's underlying pathogenic mechanisms. This concept is based on inference rather than evidence, and has limited the scope and persistence of AChEI use in clinical practice. Recent preclinical studies demonstrate that AChEIs exhibit a number of biological effects in addition to cholinesterase inhibition. A broader understanding of the possible mechanisms of action of AChEIs in Alzheimer's disease could result in more effective use and assist in the development of new and improved therapies. The available evidence brings into question the prevailing view that AChEIs are exclusively symptomatic treatments and supports the use of these agents persistently throughout the course of Alzheimer's disease.

Donepezil inhibits the amyloid-beta oligomer-induced microglial activation in vitro and in vivo

Recent studies on Alzheimer's disease (AD) have focused on soluble oligomeric forms of amyloid-beta (Aβ oligomer, AβO) that are directly associated with AD-related pathologies, such as cognitive decline, neurodegeneration, and neuroinflammation. Donepezil is a well-known anti-dementia agent that increases acetylcholine levels through inhibition of acetylcholinesterase. However, a growing body of experimental and clinical studies indicates that donepezil may also provide neuroprotective and disease-modifying effects in AD. Additionally, donepezil has recently been demonstrated to have anti-inflammatory effects against lipopolysaccharides and tau pathology. However, it remains unknown whether donepezil has anti-inflammatory effects against AβO in cultured microglial cells and the brain in animals. Further, the effects of donepezil against AβO-mediated neuronal death, astrogliosis, and memory impairment have also not yet been investigated. Thus, in the present study, we examined the anti-inflammatory effect of donepezil against AβO and its neuroinflammatory mechanisms. Donepezil significantly attenuated the release of inflammatory mediators (prostaglandin E2, interleukin-1 beta, tumor necrosis factor-α, and nitric oxide) from microglia. Donepezil also decreased AβO-induced up-regulation of inducible nitric oxide synthase and cyclooxygenase-2 protein and phosphorylation of p38 mitogen-activated protein kinase as well as translocation of nuclear factor-kappa B. We next showed that donepezil suppresses activated microglia-mediated toxicity in primary hippocampal cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. In intrahippocampal AβO-injected mice, donepezil significantly inhibited microgliosis and astrogliosis. Furthermore, behavioral tests revealed that donepezil (2 mg/kg/day, 5 days, p.o.) significantly ameliorated AβO-induced memory impairment. These results suggest that donepezil directly inhibits microglial activation induced by AβO through blocking MAPK and NF-κB signaling and, in part, contributing to the amelioration of neurodegeneration and memory impairment.

A contrast in safety, pharmacokinetics and pharmacodynamics across age groups after a single 50 mg oral dose of the γ-secretase inhibitor avagacestat

AIM

To evaluate the single dose pharmacokinetics, pharmacodynamics, and preliminary tolerability of the γ-secretase inhibitor BMS-708163 (avagacestat) in young and elderly men and women.

METHODS

All subjects received double-blinded administration of a single 50 mg dose of avagacestat in capsule form or matching placebo. Main evaluations included pharmacokinetics, safety, plasma amyloid-β (Aβ)(1-40) concentratios and exploration of Notch biomarkers.

RESULTS

Avagacestat 50 mg capsule was well tolerated and rapidly absorbed among young and elderly subjects, with a median t(max) between 1 and 2 h post dose and an average half-life between 41 and 71 h. In general, subjects aged 75 years or more had higher AUC(0,∞) values than those aged less than 75 years. An exploratory analysis of Aβ(1-40) serum concentrations showed a pattern of decreasing concentrations over the first 4-6 h followed by a rise above baseline that was maintained until the end of the assessment period. Adverse events were generally mild, occurring more frequently in elderly subjects, with no observed difference between subjects receiving avagacestat and placebo. No dose limiting gastrointestinal effects of avagacestat were observed and exploratory biomarkers of Notch inhibition did not change significantly.

CONCLUSIONS

The favourable safety profile and pharmacokinetic effects of avagacestat in this study support its continued development, especially in the target population of elderly subjects with mild cognitive impairment or Alzheimer's disease.

Prediction models for assessing long-term outcome in Alzheimer's disease: a review

In Alzheimer's disease (AD), placebo-controlled long-term studies of cholinesterase inhibitors (ChEIs) are not permitted for ethical reasons. Therefore, in these studies, patients' outcomes on cognitive and functional assessment scales must be compared with mathematical models or historical data from untreated cohorts. PubMed and previously published long-term extensions of clinical trials and naturalistic studies of ChEIs were examined to identify empirical statistical models and other approaches, such as use of data from historical cohorts or extrapolated changes from extension studies, that were used to draw comparisons between ChEI-treated and untreated patients. The models and methods were described. It is essential to be aware of the limitations of comparisons made with these approaches. Prediction models based on ChEI-treated patients can be used in the studies of new treatments when those treatments are added to ChEIs. More sophisticated models that also accommodate patient-specific characteristics should be developed for comparisons in future long-term AD studies.

Therapeutics of Alzheimer's disease: Past, present and future

Alzheimer's disease (AD) is the most common cause of dementia worldwide. The etiology is multifactorial, and pathophysiology of the disease is complex. Data indicate an exponential rise in the number of cases of AD, emphasizing the need for developing an effective treatment. AD also imposes tremendous emotional and financial burden to the patient's family and community. The disease has been studied over a century, but acetylcholinesterase inhibitors and memantine are the only drugs currently approved for its management. These drugs provide symptomatic improvement alone but do less to modify the disease process. The extensive insight into the molecular and cellular pathomechanism in AD over the past few decades has provided us significant progress in the understanding of the disease. A number of novel strategies that seek to modify the disease process have been developed. The major developments in this direction are the amyloid and tau based therapeutics, which could hold the key to treatment of AD in the near future. Several putative drugs have been thoroughly investigated in preclinical studies, but many of them have failed to produce results in the clinical scenario; therefore it is only prudent that lessons be learnt from the past mistakes. The current rationales and targets evaluated for therapeutic benefit in AD are reviewed in this article. This article is part of the Special Issue entitled 'The Synaptic Basis of Neurodegenerative Disorders'.