Rivastigmine for Alzheimer's disease

An inclusive study of recent advancements in Alzheimer's disease: A comprehensive review

Alzheimer's disease (AD) has remained elusive in revealing its pathophysiology and mechanism of development. In this review paper, we attempt to highlight several theories that abound about the exact pathway of AD development. The number of cases worldwide has prompted a constant flow of research to detect high-risk patients, slow the progression of the disease and discover improved methods of treatment that may prove effective. We shall focus on the two main classes of drugs that are currently in use; and emerging ones with novel mechanisms that are under development. As of late there has also been increased attention towards factors that were previously thought to be unrelated to AD, such as the gut microbiome, lifestyle habits, and diet. Studies have now shown that all these factors make an impact on AD progression, thus bringing to our attention more areas that could hold the key to combating this disease. This paper covers all the aforementioned factors concisely. We also briefly explore the relationship between mental health and AD, both before and after the diagnosis of the disease.

Advances on Therapeutic Strategies for Alzheimer’s Disease: From Medicinal Plant to Nanotechnology

Alzheimer’s disease (AD) is a chronic dysfunction of neurons in the brain leading to dementia. It is characterized by gradual mental failure, abnormal cognitive functioning, personality changes, diminished verbal fluency, and speech impairment. It is caused by neuronal injury in the cerebral cortex and hippocampal area of the brain. The number of individuals with AD is growing at a quick rate. The pathology behind AD is the progress of intraneuronal fibrillary tangles, accumulation of amyloid plaque, loss of cholinergic neurons, and decrease in choline acetyltransferase. Unfortunately, AD cannot be cured, but its progression can be delayed. Various FDA-approved inhibitors of cholinesterase enzyme such as rivastigmine, galantamine, donepezil, and NDMA receptor inhibitors (memantine), are available to manage the symptoms of AD. An exhaustive literature survey was carried out using SciFinder’s reports from Alzheimer’s Association, PubMed, and Clinical Trials.org. The literature was explored thoroughly to obtain information on the various available strategies to prevent AD. In the context of the present scenario, several strategies are being tried including the clinical trials for the treatment of AD. We have discussed pathophysiology, various targets, FDA-approved drugs, and various drugs in clinical trials against AD. The goal of this study is to shed light on current developments and treatment options, utilizing phytopharmaceuticals, nanomedicines, nutraceuticals, and gene therapy.

Real-world Evaluation of Tolerability, Safety and Efficacy of Rivastigmine Oral Solution in Patients with Mild to Moderate Alzheimer's Disease Dementia

Objective

The purpose of this study is to investigate the safety, tolerability and efficacy of titrating dose of rivastigmine oral solution in patients with mild to moderate Alzheimer’s disease (AD) in Taiwan.

Methods

We recruited 108 mild to moderate AD patients with Rivast^Ⓡ (rivastigmine oral solution 2 mg/ml) treatment for 52 weeks. We recorded the demographic characteristics, initial cognition by mini-mental state examination (MMSE), initial global status by clinical dementia rating (CDR) with CDR-Sum of Boxes (CDR-SB), initial dose, and titrating dose at each visit. We investigated the adherence, proportion of possible side effects, optimal dose, and time to optimal dose. We demonstrated the proportion of cognitive decline and its possible risk factors.

Results

During the course, 9 patients discontinued the rivastigmine oral solution due to poor compliance or preference. Twelve out of 99 patients (12.1%) reported possible side effects. Among 87 patients, the mean age was 77.2 ± 9.0 years ago with female predominant (65.2%). The optimal dose was 3.6 ± 1.4 ml in average and 4 ml (n = 31, 35.6%) in mode. The duration to optimal dose was 12.5 ± 10.2 weeks and 24 weeks (n = 35, 40.2%) in mode. It presented 25% with cognitive decline in MMSE, 27% with global function decline in CDR and 63% with global function decline in CDR-SB.

Conclusion

We demonstrated the clinical experience of rivastigmine oral solution in mild to moderate AD patients. It suggested rivastigmine oral solution 4ml is the optimal dose with 24 weeks to the optimal dose for at least one third of patients.

Comprehensive Review on Alzheimer's Disease: Causes and Treatment

Alzheimer’s disease (AD) is a disorder that causes degeneration of the cells in the brain and it is the main cause of dementia, which is characterized by a decline in thinking and independence in personal daily activities. AD is considered a multifactorial disease: two main hypotheses were proposed as a cause for AD, cholinergic and amyloid hypotheses. Additionally, several risk factors such as increasing age, genetic factors, head injuries, vascular diseases, infections, and environmental factors play a role in the disease. Currently, there are only two classes of approved drugs to treat AD, including inhibitors to cholinesterase enzyme and antagonists to N-methyl d-aspartate (NMDA), which are effective only in treating the symptoms of AD, but do not cure or prevent the disease. Nowadays, the research is focusing on understanding AD pathology by targeting several mechanisms, such as abnormal tau protein metabolism, β-amyloid, inflammatory response, and cholinergic and free radical damage, aiming to develop successful treatments that are capable of stopping or modifying the course of AD. This review discusses currently available drugs and future theories for the development of new therapies for AD, such as disease-modifying therapeutics (DMT), chaperones, and natural compounds.

Pleiotropic prodrugs: Design of a dual butyrylcholinesterase inhibitor and 5-HT6 receptor antagonist with therapeutic interest in Alzheimer's disease

Beside acetylcholinesterase, butyrylcholinesterase could be considered as a putative target of interest for the symptomatic treatment of Alzheimer's disease (AD). As a result of complexity of AD, no molecule has been approved since 2002. Idalopirdine, a 5-HT₆ receptors antagonist, did not show its effectiveness in clinical trial despite its evaluation as adjunct to cholinesterase inhibitors. Pleiotropic molecules, known as multitarget directed ligands (MTDLs) are currently developed to tackle the multifactorial origin of AD. In this context, we have developed a pleiotropic carbamate 7, that behaves as a covalent inhibitor of BuChE (IC₅₀ = 0.97 μM). The latter will deliver after hydrolysis, compound 6, a potent 5-HT₆ receptors antagonist (K_i = 11.4 nM) related to idalopirdine. In silico and in vitro evaluation proving our concept were performed completed with first in vivo results that demonstrate great promise in restoring working memory.

Double Optimization of Rivastigmine-Loaded Nanostructured Lipid Carriers (NLC) for Nose-to-Brain Delivery Using the Quality by Design (QbD) Approach: Formulation Variables and Instrumental Parameters

Rivastigmine is a drug commonly used in the management of Alzheimer's disease that shows bioavailability problems. To overcome this, the use of nanosystems, such as nanostructured lipid carriers (NLC), administered through alternative routes seems promising. In this work, we performed a double optimization of a rivastigmine-loaded NLC formulation for direct drug delivery from the nose to the brain using the quality by design (QbD) approach, whereby the quality target product profile (QTPP) was the requisite for nose to brain delivery. The experiments started with the optimization of the formulation variables (or critical material attributes-CMAs) using a central composite design. The rivastigmine-loaded NLC formulations with the best critical quality attributes (CQAs) of particle size, polydispersity index (PDI), zeta potential (ZP), and encapsulation efficiency (EE) were selected for the second optimization, which was related to the production methods (ultrasound technique and high-pressure homogenization). The most suitable instrumental parameters for the production of NLC were analyzed through a Box-Behnken design, with the same CQAs being evaluated for the first optimization. For the second part of the optimization studies, were selected two rivastigmine-loaded NLC formulations: one produced by ultrasound technique and the other by the high-pressure homogenization (HPH) method. Afterwards, the pH and osmolarity of these formulations were adjusted to the physiological nasal mucosa values and in vitro drug release studies were performed. The results of the first part of the optimization showed that the most adequate ratios of lipids and surfactants were 7.49:1.94 and 4.5:0.5 (%, w/w), respectively. From the second part of the optimization, the results for the particle size, PDI, ZP, and EE of the rivastigmine-loaded NLC formulations produced by ultrasound technique and HPH method were, respectively, 114.0 ± 1.9 nm and 109.0 ± 0.9 nm; 0.221 ± 0.003 and 0.196 ± 0.007; -30.6 ± 0.3 mV and -30.5 ± 0.3 mV; 97.0 ± 0.5% and 97.2 ± 0.3%. Herein, the HPH was selected as the most suitable production method, although the ultrasound technique has also shown effectiveness. In addition, no significant changes in CQAs were observed after 90 days of storage of the formulations at different temperatures. In vitro studies showed that the release of rivastigmine followed a non-Fickian mechanism, with an initial fast drug release followed by a prolonged release over 48 h. This study has optimized a rivastigmine-loaded NLC formulation produced by the HPH method for nose-to-brain delivery of rivastigmine. The next step is for in vitro and in vivo experiments to demonstrate preclinical efficacy and safety. QbD was demonstrated to be a useful approach for the optimization of NLC formulations for which specific physicochemical requisites can be identified.

Cholinesterase Inhibitors for Alzheimer's Disease: Multitargeting Strategy Based on Anti-Alzheimer's Drugs Repositioning

In the brain, acetylcholine (ACh) is regarded as one of the major neurotransmitters. During the advancement of Alzheimer's disease (AD) cholinergic deficits occur and this can lead to extensive cognitive dysfunction and decline. Acetylcholinesterase (AChE) remains a highly feasible target for the symptomatic improvement of AD. Acetylcholinesterase (AChE) remains a highly viable target for the symptomatic improvement in AD because cholinergic deficit is a consistent and early finding in AD. The treatment approach of inhibiting peripheral AChE for myasthenia gravis had effectively proven that AChE inhibition was a reachable therapeutic target. Subsequently tacrine, donepezil, rivastigmine, and galantamine were developed and approved for the symptomatic treatment of AD. Since then, multiple cholinesterase inhibitors (ChEIs) have been continued to be developed. These include newer ChEIs, naturally derived ChEIs, hybrids, and synthetic analogues. In this paper, we summarize the different types of ChEIs which are under development and their respective mechanisms of actions.

Application of Healthcare 'Big Data' in CNS Drug Research: The Example of the Neurological and mental health Global Epidemiology Network (NeuroGEN)

Neurological and psychiatric (mental health) disorders have a large impact on health burden globally. Cognitive disorders (including dementia) and stroke are leading causes of disability. Mental health disorders, including depression, contribute up to one-third of total years lived with disability. The Neurological and mental health Global Epidemiology Network (NeuroGEN) is an international multi-database network that harnesses administrative and electronic medical records from Australia, Asia, Europe and North America. Using these databases NeuroGEN will investigate medication use and health outcomes in neurological and mental health disorders. A key objective of NeuroGEN is to facilitate high-quality observational studies to address evidence-practice gaps where randomized controlled trials do not provide sufficient information on medication benefits and risks that is specific to vulnerable population groups. International multi-database research facilitates comparisons across geographical areas and jurisdictions, increases statistical power to investigate small subpopulations or rare outcomes, permits early post-approval assessment of safety and effectiveness, and increases generalisability of results. Through bringing together international researchers in pharmacoepidemiology, NeuroGEN has the potential to be paradigm-changing for observational research to inform evidence-based prescribing. The first focus of NeuroGEN will be to address evidence-gaps in the treatment of chronic comorbidities in people with dementia.

Targeting Inflammatory Pathways in Alzheimer's Disease: A Focus on Natural Products and Phytomedicines

Studies of the brains of Alzheimer's disease (AD) patients have revealed key neuropathological features, such as the deposition of aggregates of insoluble amyloid-β (Aβ) peptides and neurofibrillary tangles (NFTs). These pathological protein deposits, including Aβ peptides (which form senile plaques) and hyperphosphorylated tau (which aggregates into NFTs), have been assumed to be 'the cause of AD'. Aβ has been extensively targeted to develop an effective disease-modifying therapy, but with limited clinical success. Emerging therapies are also now targeting further pathological processes in AD, including neuroinflammation. This review focuses on the inflammatory and oxidative stress-related changes that occur in AD, and discusses some emerging anti-inflammatory natural products and phytomedicines. Many of the promising compounds are cytokine-suppressive anti-inflammatory drugs (CSAIDs), which target the proinflammatory AP1 and nuclear factor-κB signalling pathways and inhibit the expression of many proinflammatory cytokines, such as interleukin (IL)-1, IL-6, tumour necrosis factor-α, or nitric oxide produced by inducible nitric oxide synthase. However, many of these phytomedicines have not been tested in rigorous clinical trials in AD patients. It is not yet clear if the active compounds reach an effective concentration in the brain (due to limited bioavailability) or if they can slow down AD progression in long-term trials. The authors suggest that it is crucial for both the pharmacological and complementary medicine industries to conduct and fund those studies to significantly advance the field.

Identification of the optimal cognitive drugs among Alzheimer's disease: a Bayesian meta-analytic review

PURPOSE

The increasing prevalence of Alzheimer's disease (AD) demands more effective drugs, which are still unclear. The aim of this study is to compare the effectiveness of six drugs, such as donepezil, rivastigmine, galantamine, memantine, huperzine-A, and tacrine, in senior AD patients and identify the most effective one to improve patients' cognitive function.

METHODS

A system of search strategies was used to identify relevant studies including randomized controlled trials and clinical controlled trials evaluating the efficacy of six drugs in patients with AD. We updated relevant studies that were published before March 2018 as full-text articles. Using Bayesian network meta-analysis (NMA), we ranked cognitive ability objectively based on Mini-Mental State Examination (MMSE). Pairwise and NMAs were sequentially performed for the efficacy of drugs compared to each drug or control group through the trials included.

RESULTS

Among the 35 trials included, no obvious heterogeneity (I 2=0.0%, P=0.583) was revealed according to the pooled data for cognition in NMA and the mean difference (MD) of memantine (MD=1.7, 95% CI: 0.73, 2.8) showed that the memantine was significantly efficacious in the treatment group in terms of MMSE. Followed by galantamine, huperzine-A, rivastigmine, tacrine, and donepezil.

CONCLUSION

As the first NMA comparing the major drugs in market for AD, our study suggests that memantine might have a more significant benefit on cognition than other five drugs available.

Deciphering T Cell Immunometabolism with Activity-Based Protein Profiling

As a major sentinel of adaptive immunity, T cells seek and destroy diseased cells using antigen recognition to achieve molecular specificity. Strategies to block checkpoint inhibition of T cell activity and thus reawaken the patient's antitumor immune responses are rapidly becoming standard of care for treatment of diverse cancers. Adoptive transfer of patient T cells genetically engineered with tumor-targeting capabilities is redefining the field of personalized medicines. The diverse opportunities for exploiting T cell biology in the clinic have prompted new efforts to expand the scope of targets amenable to immuno-oncology. Given the complex spatiotemporal regulation of T cell function and fate, new technologies capable of global molecular profiling in vivo are needed to guide selection of appropriate T cell targets and subsets. In this chapter, we describe the use of activity-based protein profiling (ABPP) to illuminate different aspects of T cell metabolism and signaling as fertile starting points for investigation. We highlight the merits of ABPP methods to enable target, inhibitor, and biochemical pathway discovery of T cells in the burgeoning field of immuno-oncology.

Basal Forebrain Volume, but Not Hippocampal Volume, Is a Predictor of Global Cognitive Decline in Patients With Alzheimer's Disease Treated With Cholinesterase Inhibitors

Background: Predicting the progression of cognitive decline in Alzheimer's disease (AD) is important for treatment selection and patient counseling. Structural MRI markers such as hippocampus or basal forebrain volumes might represent useful instruments for the prediction of cognitive decline. The primary objective was to determine the predictive value of hippocampus and basal forebrain volumes for global and domain specific cognitive decline in AD dementia during cholinergic treatment. Methods: We used MRI and cognitive data from 124 patients with the clinical diagnosis of AD dementia, derived from the ADNI-1 cohort, who were on standard of care cholinesterase inhibitor treatment during a follow-up period between 0.4 and 3.1 years. We used linear mixed effects models with cognitive function as outcome to assess the main effects as well as two-way interactions between baseline volumes and time controlling for age, sex, and total intracranial volume. This model accounts for individual variation in follow-up times. Results: Basal forebrain volume, but not hippocampus volume, was a significant predictor of rates of global cognitive decline. Larger volumes were associated with smaller rates of cognitive decline. Left hippocampus volume had a modest association with rates of episodic memory decline. Baseline performance in global cognition and memory was significantly associated with hippocampus and basal forebrain volumes; in addition, basal forebrain volume was associated with baseline performance in executive function. Conclusions: Our findings indicate that in AD dementia patients, basal forebrain volume may be a useful marker to predict subsequent cognitive decline during cholinergic treatment.

An anti-nicotinic cognitive challenge model using mecamylamine in comparison with the anti-muscarinic cognitive challenge using scopolamine

AIMS

The muscarinic acetylcholine receptor antagonist scopolamine is often used for proof-of-pharmacology studies with pro-cognitive compounds. From a pharmacological point of view, it would seem more rational to use a nicotinic rather than a muscarinic anticholinergic challenge to prove pharmacology of a nicotinic acetylcholine receptor agonist. This study aims to characterize a nicotinic anticholinergic challenge model using mecamylamine and to compare it to the scopolamine model.

METHODS

In this double-blind, placebo-controlled, four-way cross-over trial, 12 healthy male subjects received oral mecamylamine 10 and 20 mg, intravenous scopolamine 0.5 mg and placebo. Pharmacokinetics were analysed using non-compartmental analysis. Pharmacodynamic effects were measured with a multidimensional test battery that includes neurophysiological, subjective, (visuo)motor and cognitive measurements.

RESULTS

All treatments were safe and well tolerated. Mecamylamine had a tmax of 2.5 h and a Cmax of 64.5 ng ml-1 for the 20 mg dose. Mecamylamine had a dose-dependent effect decreasing the adaptive tracking performance and VAS alertness, and increasing the finger tapping and visual verbal learning task performance time and errors. Scopolamine significantly affected almost all pharmacodynamic tests.

CONCLUSION

This study demonstrated that mecamylamine causes nicotinic receptor specific temporary decline in cognitive functioning. Compared with the scopolamine model, pharmacodynamic effects were less pronounced at the dose levels tested; however, mecamylamine caused less sedation. The cognitive effects of scopolamine might at least partly be caused by sedation. Whether the mecamylamine model can be used for proof-of-pharmacology of nicotinic acetylcholine receptor agonists remains to be established.

Prediction of Anti-Alzheimer's Activity of Flavonoids Targeting Acetylcholinesterase in silico

INTRODUCTION

Prenylated and pyrano-flavonoids of the genus Artocarpus J. R. Forster & G. Forster are well known for their acetylcholinesterase (AChE) inhibitory, anti-cholinergic, anti-inflammatory, anti-microbial, anti-oxidant, anti-proliferative and tyrosinase inhibitory activities. Some of these compounds have also been shown to be effective against Alzheimer's disease.

OBJECTIVE

The aim of the in silico study was to establish protocols to predict the most effective flavonoid from prenylated and pyrano-flavonoid classes for AChE inhibition linking to the potential treatment of Alzheimer's disease.

METHODOLOGY

Three flavonoids isolated from Artocarpus anisophyllus Miq. were selected for the study. With these compounds, Lipinski filter, ADME/Tox screening, molecular docking and quantitative structure-activity relationship (QSAR) were performed in silico. In vitro activity was evaluated by bioactivity staining based on the Ellman's method.

RESULTS

In the Lipinski filter and ADME/Tox screening, all test compounds produced positive results, but in the target fishing, only one flavonoid could successfully target AChE. Molecular docking was performed on this flavonoid, and this compound gained the score as -13.5762. From the QSAR analysis the IC₅₀ was found to be 1659.59 nM. Again, 100 derivatives were generated from the parent compound and docking was performed. The derivative compound 20 was the best scorer, i.e. -31.6392 and IC₅₀ was predicted as 6.025 nM.

CONCLUSION

Results indicated that flavonoids could be efficient inhibitors of AChE and thus, could be useful in the management of Alzheimer's disease. Copyright © 2017 John Wiley & Sons, Ltd.

Poor physical fitness is independently associated with mild cognitive impairment in elderly Koreans

The purpose of this study was to investigate the association between physical fitness and mild cognitive impairment (MCI) in elderly Koreans. This was a cross-sectional study that involved 134 men and 299 women aged 65 to 88 years. Six senior fitness tests were used as independent variables: 30 s chair stand for lower body strength, arm curl for upper body strength, chair-sit-and-reach for lower body flexibility, back scratch for upper body flexibility, 8-ft up-and-go for agility/dynamic balance, and 2-min walk for aerobic endurance. Global cognitive function was assessed using the Korean version of the Mini-Mental State Examination (MMSE). Potential covariates such as age, education levels, blood lipids, and insulin resistance (IR) markers were also assessed. Compared to individuals without MMSE-based MCI, individuals with MMSE-based MCI had poor physical fitness based on the senior fitness test (SFT). There were significant positive trends observed for education level (p=0.001) and MMSE score (p<0.001) across incremental levels of physical fitness in this study population. Individuals with moderate (OR=0.341, p=0.006) and high (OR=0.271, p=0.007) physical fitness based on a composite score of the SFT measures were less likely to have MMSE-based MCI than individuals with low physical fitness (referent, OR=1). The strength of the association between moderate (OR=0.377, p=0.038) or high (OR=0.282, p=0.050) physical fitness and MMSE-based MCI was somewhat attenuated but remained statistically significant even after adjustment for the measured compounding factors. We found that poor physical fitness was independently associated with MMSE-based MCI in elderly Koreans.

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

INTRODUCTION

Alzheimer's dementia (AD) is the most common cause of dementia, and several organisations, such as the National Institute for Health and Care Excellence, suggest that management of patients with AD should be tailored to their needs. To date, little research has been conducted on the treatment effect in different subgroups of patients with AD. The aim of this study is to examine the comparative effectiveness and safety of cognitive enhancers for different patient characteristics.

METHODS AND ANALYSIS

We will update our previous literature search from January 2015 forward, using the same terms and electronic databases (eg, MEDLINE) from our previous review. We will additionally search grey literature and scan the reference lists of the included studies. Randomised clinical trials of any duration conducted at any time comparing cognitive enhancers alone or in any combination against other cognitive enhancers, or placebo in adults with AD will be eligible. The outcomes of interest are cognition according to the Mini-Mental State Examination, and overall serious adverse events. For each outcome and treatment comparison, we will perform a Bayesian hierarchical random-effects meta-analysis combining the individual patient data (IPD) from each eligible study. If the identified treatment comparisons form a connected network diagram, we will perform an IPD network meta-analysis (NMA) to estimate subgroup effects for patients with different characteristics, such as AD severity and sex. We will combine aggregated data from studies that we will not be able to obtain IPD, with the IPD provided by the original authors, in a single model. We will use the PRISMA-IPD and PRISMA-NMA statements to report our findings.

ETHICS AND DISSEMINATION

The findings of this study will be of interest to stakeholders, including decision makers, guideline developers, clinicians, methodologists and patients, and they will help to improve guidelines for the management of patients with AD.

TRIAL REGISTRATION NUMBER

CRD42015023507.

First in human study with a prodrug of galantamine: Improved benefit-risk ratio?

INTRODUCTION

Gln-1062 (Memogain) is a pharmacologically inactive prodrug of galantamine. Owing to its lipophilic nature, it preferentially enters the brain, where it is cleaved into active galantamine. Gln-1062 is expected to have fewer peripheral side effects than other cholinesterase inhibitors, with improved effectiveness.

METHODS

This was a double-blind, comparator and placebo-controlled, sequential cohort, single ascending dose study in 58 healthy subjects with Gln-1062 in doses of 5.5, 11, 22, 33, and 44 mg, compared with oral galantamine 16 mg and donepezil 10 mg. Safety, tolerability, pharmacokinetics, and pharmacodynamics were assessed.

RESULTS

Gln-1062 doses up to 33 mg were well tolerated and induced a dose-dependent increase in the plasma concentrations of Gln-1062 and galantamine. Gln-1062 had a dose-dependent positive effect on verbal memory and attention, mainly in the first hours after drug administration.

DISCUSSION

Gln-1062 was better tolerated than galantamine in doses with the same molarity and led to improved effects in cognitive tests. This is most likely caused by the more favorable distribution ratio between peripheral and central cholinesterase inhibition. These results give reason for further exploration of this compound.

Current Treatment Options for Alzheimer's Disease and Parkinson's Disease Dementia

Alzheimer's disease (AD) and Parkinson's disease (PD) are the two most common neurodegenerative disorders encountered in clinical practice. Whilst dementia has long been synonymous with AD, it is becoming more widely accepted as part of the clinical spectrum in PD (PDD). Neuropsychiatric complications, including psychosis, mood and anxiety disorders, and sleep disorders also frequently co-exist with cognitive dysfunctions in AD and PDD patients. The incidence of such symptoms is often a significant source of disability, and may aggravate pre-existing cognitive deficits. Management of AD and PDD involves both pharmacological and non-pharmacological measures. Although research on pharmacological therapies for AD and PDD has so far had some success in terms of developing symptomatic treatments, the benefits are often marginal and non-sustained. These shortcomings have led to the investigation of non-pharmacological and novel treatments for both AD and PD. Furthermore, in light of the diverse constellation of other neuropsychiatric, physical, and behavioural symptoms that often occur in AD and PD, consideration needs to be given to the potential side effects of pharmacological treatments where improving one symptom may lead to the worsening of another, rendering the clinical management of these patients challenging. Therefore, the present article will critically review the evidence for both pharmacological and non-pharmacological treatments for cognitive impairment in AD and PD patients. Treatment options for other concomitant neuropsychiatric and behavioural symptoms, as well as novel treatment strategies will also be discussed.

Cerebrolysin in mild-to-moderate Alzheimer's disease: a meta-analysis of randomized controlled clinical trials

OBJECTIVE

The aim of this study was to provide a systematic and quantitative summary of benefit and risk of Cerebrolysin in patients with mild-to-moderate Alzheimer's disease (AD) and to avoid major deficiencies of an earlier meta-analysis.

DESIGN

This is a meta-analysis of randomized double-blind placebo-controlled clinical trials.

DATA SOURCES

Trials were identified with the help of PubMed, the Cochrane Dementia Group database, the Center for Collaborative Neurosciences, and references from reviews; no language restrictions were applied.

STUDY SELECTION

All randomized double-blind placebo-controlled studies on 30 ml/day of Cerebrolysin in mild-to-moderate AD were included.

RESULTS

There were 6 eligible randomized controlled trials comparing Cerebrolysin with placebo. For all studies, either individual patient data and/or published data (aggregate data) were available. Analyses were based on the odds ratio (OR) for dichotomized global clinical change and for safety criteria, on the standardized mean difference (SMD) for pooling of cognitive function, and on the Mann-Whitney statistic (MW) for multivariate analysis of 'global benefit' (combined effect of global clinical change and cognitive function). Cerebrolysin was significantly more effective than placebo at 4 weeks regarding cognitive function (4 weeks: SMD -0.40 points; 95% CI -0.66 to -0.13; p = 0.0031; 6 months: SMD -0.37 points; 95% CI -0.90 to 0.16; p = 0.1710), at 4 weeks and 6 months regarding global clinical change (4 weeks: OR 3.32; 95% CI 1.20-9.21; p = 0.0212; 6 months: OR 4.98; 95% CI 1.37-18.13; p = 0.0150), and at 4 weeks and 6 months regarding 'global benefit' (combined efficacy criteria; 4 weeks: MW 0.57, 95% CI 0.53-0.61; p = 0.0006; 6 months: MW 0.57; 95% CI 0.53-0.61; p = 0.0010). The safety aspects of Cerebrolysin were comparable to placebo.

CONCLUSION

This meta-analysis provides evidence that Cerebrolysin has an overall beneficial effect and a favorable benefit-risk ratio in patients with mild-to-moderate AD. Cerebrolysin as a therapeutic agent should be considered by clinicians seeking treatment options for mild-to-moderate AD.

A 24-Week, Randomized, Controlled Study to Evaluate the Tolerability, Safety and Efficacy of 2 Different Titration Schemes of the Rivastigmine Patch in Japanese Patients with Mild to Moderate Alzheimer's Disease

Aim

To investigate whether 1-step titration of the rivastigmine patch (initiated at 5 cm² and titrated to 10 cm² after 4 weeks) is well tolerated in Japanese patients with Alzheimer's disease (AD) as compared to 3-step titration (initiated at 2.5 cm² and titrated by 2.5 cm² every 4 weeks to 10 cm²).

Methods

A 24-week, multicenter, randomized, double-blind study was conducted in Japan between July 2012 and May 2014. Patients with mild to moderate AD aged 50-85 years were randomized 1:1 to 1-step or 3-step titration of the rivastigmine once-daily patch. The primary endpoint was the proportion of patients with adverse events leading to discontinuation.

Results

Of 216 patients randomized, 215 (1-step, n = 107; 3-step, n = 108) were included in the safety analysis. The primary endpoint outcome was 15.0% in the 1-step group and 18.5% in the 3-step group. The observed treatment difference was −3.6% (95% confidence interval: −17.0, 9.6), falling within the prespecified acceptance range.

Conclusion

The tolerability of two different titration schemes was similar in Japanese patients with AD.

Dutch family physicians' awareness of cognitive impairment among the elderly

BACKGROUND

Dementia is often not formally diagnosed in primary care. To what extent this is due to family physicians' (FPs) watchful waiting, reluctance to diagnose or to their unawareness of the presence of cognitive impairment is unclear. The objective of this study was to assess FPs' awareness of cognitive impairment by comparing their evaluation of the absence or presence of cognitive impairment in older patients without an established diagnosis of dementia, with a reference test of cognitive functioning. In addition, we assessed which patient characteristics were associated with con- and discordance between FPs' evaluation of cognition and results of the reference test.

METHODS

The design was a nested diagnostic study. FPs (n = 29) of 15 primary care practices classified the cognitive status of all their patients ≥ 65 years of age (n = 7865) into four categories, based on recollection and medical records. All patients categorized as 'possible cognitive impairment or dementia' and a sample of patients categorized as 'no signs of cognitive impairment' randomly selected to match age and gender were offered to receive a reference test of cognitive function (the CAMCOG) to verify the FPs' label. This reference test could yield three outcomes: no cognitive impairment, amnestic mild cognitive impairment (aMCI) or dementia. Reference test results were weighted back to the original samples to provide estimates for the correct categorization of elderly as 'possible cognitive impairment or dementia' (positive predictive value [PPV]) and 'no signs of cognitive impairment' (negative predictive value [NPV]). Cognitive functioning was not assessed for patients evaluated by FPs as 'probable dementia' and 'unknown or no recent contact'. Characteristics associated with the con- or discordance of the FPs' classification and the reference test were assessed using logistic regression.

RESULTS

Complete reference test results were obtained from 318 elderly. FPs labeled 8.3 % of elderly 'possible cognitive impairment or dementia'. The PPV of this label for a CAMCOG score suggestive of dementia or aMCI was 47.1 % (95 %-confidence interval: 43.5 - 62.4 %). FPs labeled 83.7 % 'no signs of cognitive impairment'. The 1-NPV of this label for a CAMCOG score suggestive of dementia or aMCI was 12.5 % (95 %-CI 8.2 - 16.8 %). FPs labeled 3.6 % as 'probable dementia' and 4.5 % as 'unknown or no recent contact'. The odds that FPs' suspicion of cognitive impairment were confirmed by the CAMCOG were higher if persons were ADL dependent (OR 2.24 [95 %-CI 1.16 - 4.35]). The odds of FPs being unaware of the presence of cognitive impairment were higher in the older elderly (OR 1.15 [95 %-CI 1.09 - 1.23] per year).

CONCLUSION

Evaluation of FPs' classification of the global cognitive function of elderly without a firm diagnosis of dementia showed both over- and unawareness of the presence of cognitive impairment. FPs were more often unaware of cognitive impairment in the older elderly.

Drug therapies in older adults (part 1)

Prescribing for older adults represents a significant challenge as the UK population ages. Physiological decline and the rising prevalence of frailty increase the likelihood of altered pharmacodynamics and pharmacokinetics, suboptimal prescribing and adverse effects among this growing cohort of the population. In the first of two articles, we begin by considering these issues and posit four key questions which should be considered when prescribing for older adults. Does this agent reflect the priorities of the patient? Are there alternatives - with greater efficacy, effectiveness or tolerability - that might be considered? Are the dose, frequency and formulation appropriate? How does this prescription relate to concurrent medication? We also describe current drug therapies in two disease states with a predilection for older adults: Alzheimer's disease (AD) and osteoporosis. Using these examples we highlight the limitations of evidence-based medicine and guidelines in this cohort of the population, illustrating the reliance on sub-group analysis to demonstrate the efficacy of drug therapies for older adults in osteoporosis and the underutilisation of appropriate treatments for patients with AD as a result of flawed guidelines.

Clinical trials and late-stage drug development for Alzheimer's disease: an appraisal from 1984 to 2014

The modern era of drug development for Alzheimer's disease began with the proposal of the cholinergic hypothesis of memory impairment and the 1984 research criteria for Alzheimer's disease. Since then, despite the evaluation of numerous potential treatments in clinical trials, only four cholinesterase inhibitors and memantine have shown sufficient safety and efficacy to allow marketing approval at an international level. Although this is probably because the other drugs tested were ineffective, inadequate clinical development methods have also been blamed for the failures. Here, we review the development of treatments for Alzheimer's disease during the past 30 years, considering the drugs, potential targets, late-stage clinical trials, development methods, emerging use of biomarkers and evolution of regulatory considerations in order to summarize advances and anticipate future developments. We have considered late-stage Alzheimer's disease drug development from 1984 to 2013, including individual clinical trials, systematic and qualitative reviews, meta-analyses, methods, commentaries, position papers and guidelines. We then review the evolution of drugs in late clinical development, methods, biomarkers and regulatory issues. Although a range of small molecules and biological products against many targets have been investigated in clinical trials, the predominant drug targets have been the cholinergic system and the amyloid cascade. Trial methods have evolved incrementally: inclusion criteria have largely remained focused on mild-to-moderate Alzheimer's disease criteria, recently extending to early or prodromal Alzheimer disease or 'mild cognitive impairment due to Alzheimer's disease', for drugs considered to be disease modifying. The duration of trials has remained at 6-12 months for drugs intended to improve symptoms; 18- to 24-month trials have been established for drugs expected to attenuate clinical course. Cognitive performance, activities of daily living, global change and severity ratings have persisted as the primary clinically relevant outcomes. Regulatory guidance and oversight have evolved to allow for enrichment of early-stage Alzheimer's disease trial samples using biomarkers and phase-specific outcomes. In conclusion, validated drug targets for Alzheimer's disease remain to be developed. Only drugs that affect an aspect of cholinergic function have shown consistent, but modest, clinical effects in late-phase trials. There is opportunity for substantial improvements in drug discovery and clinical development methods.

The thickness of posterior cortical areas is related to executive dysfunction in Alzheimer's disease

OBJECTIVE

To establish whether alterations of brain structures in Alzheimer's disease are associated with executive dysfunction.

METHODS

Nineteen patients with Alzheimer's disease and 22 older control subjects underwent a comprehensive evaluation. The clock drawing test, digit span test, executive motor function test, Behavioral Assessment of the Dysexecutive Syndrome battery (Rule Shift Cards test), and Stroop test were used to evaluate executive dysfunction. A multiparametric approach using the FreeSurfer image analysis suite provided a description of volumetric and geometric features of the gray matter structures.

RESULTS

The cortical thickness maps showed a negative correlation between the Behavioral Assessment of the Dysexecutive Syndrome battery (Rule Shift Cards test) and the right middle frontal gyrus; a positive correlation between the executive motor function test and the left superior parietal gyrus, left middle temporal gyrus, bilateral supramarginal gyri, right middle frontal gyrus, and right precuneus; a negative correlation between the Stroop test (part III) and the right superior parietal gyrus; and a negative correlation between the Stroop test (part III) and the right middle temporal gyrus.

CONCLUSION

Executive dysfunction in Alzheimer's disease is correlated with alterations not only in the frontal areas but also within many temporal and parietal regions.

Disease-modifying drugs in Alzheimer's disease

Alzheimer's disease (AD) is an age-dependent neurodegenerative disorder and the most common cause of dementia. The early stages of AD are characterized by short-term memory loss. Once the disease progresses, patients experience difficulties in sense of direction, oral communication, calculation, ability to learn, and cognitive thinking. The median duration of the disease is 10 years. The pathology is characterized by deposition of amyloid beta peptide (so-called senile plaques) and tau protein in the form of neurofibrillary tangles. Currently, two classes of drugs are licensed by the European Medicines Agency for the treatment of AD, ie, acetylcholinesterase inhibitors for mild to moderate AD, and memantine, an N-methyl-D-aspartate receptor antagonist, for moderate and severe AD. Treatment with acetylcholinesterase inhibitors or memantine aims at slowing progression and controlling symptoms, whereas drugs under development are intended to modify the pathologic steps leading to AD. Herein, we review the clinical features, pharmacologic properties, and cost-effectiveness of the available acetylcholinesterase inhibitors and memantine, and focus on disease-modifying drugs aiming to interfere with the amyloid beta peptide, including vaccination, passive immunization, and tau deposition.

The Alzheimer's Disease Assessment Scale-Cognitive-Plus (ADAS-Cog-Plus): an expansion of the ADAS-Cog to improve responsiveness in MCI

BACKGROUND

The Alzheimer's Disease Assessment Scale cognitive subscale (ADAS-Cog) is widely used in AD, but may be less responsive to change when used in people with mild cognitive impairment (MCI).

METHODS

Participants from the Alzheimer's Disease Neuroimaging Initiative were administered a neuropsychological battery and 1.5 T MRI scans over 2-3 years. Informants were queried regarding functional impairments. Some participants had lumbar punctures to obtain cerebrospinal fluid (CSF). We added executive functioning (EF) and functional ability (FA) items to the ADAS-Cog to generate candidate augmented measures. We calibrated these candidates using baseline data (n = 811) and selected the best candidate that added EF items alone and that added EF and FA items. We selected candidates based on their responsiveness over three years in a training sample of participants with MCI (n = 160). We compared traditional ADAS-Cog scores with the two candidates based on their responsiveness in a validation sample of participants with MCI (n = 234), ability to predict conversion to dementia (n = 394), strength of association with baseline MRI (n = 394) and CSF biomarkers (n = 193).

RESULTS

The selected EF candidate added category fluency (ADAS Plus EF), and the selected EF and FA candidate added category fluency, Digit Symbol, Trail Making, and five items from the Functional Assessment Questionnaire (ADAS Plus EF&FA). The ADAS Plus EF& FA performed as well as or better than traditional ADAS-Cog scores.

CONCLUSION

Adding EF and FA items to the ADAS-Cog may improve responsiveness among people with MCI without impairing validity.

Aspects of communication in Alzheimer's disease: clinical features and treatment options

BACKGROUND

During the course of Alzheimer's disease (AD), cognitive processes, including language and communication, become increasingly impaired. The aim of this review was to highlight the impact of communication deficits in AD, and discuss the need for effective treatments.

METHOD

PubMed was searched for studies relating to language and communication in AD. The publications identified were used as a basis for the commentary in this paper. Studies relating to the clinical effectiveness of pharmacological treatment for language and communication issues were identified systematically.

RESULTS

Communication deficits are common in AD. From the earliest disease stage, the patient's capacity for communication declines as problems develop with the use of language and all aspects of functional communication. There is a loss of the ability to communicate thoughts and needs, and it becomes increasingly difficult to interact socially and sustain personal relationships with caregivers, family, and friends. It is unsurprising that patients become frustrated at their loss of self-expression, and studies have demonstrated that impaired communication is strongly linked with the development of significant behavioral concerns. Overall, poor communication contributes to caregiver strain, and adds notably to the burden of disease. Clinical data and post-hoc analyses provide preliminary indications that anti-AD therapies (memantine and the cholinesterase inhibitors, ChEIs) and non-pharmacological cognitive-linguistic stimulation techniques may be helpful in addressing communication difficulties.

CONCLUSIONS

The capacity to treat or slow the progression of communication deficits in AD would prolong patient independence, and have a profound impact on the quality of life of patients and caregivers. The use of pharmacological (anti-AD therapies) and non-pharmacological (cognitive-linguistic stimulation) treatments may be useful management methods and warrant further investigation.

Acetylcholinesterase inhibitors: pharmacology and toxicology

Acetylcholinesterase is involved in the termination of impulse transmission by rapid hydrolysis of the neurotransmitter acetylcholine in numerous cholinergic pathways in the central and peripheral nervous systems. The enzyme inactivation, induced by various inhibitors, leads to acetylcholine accumulation, hyperstimulation of nicotinic and muscarinic receptors, and disrupted neurotransmission. Hence, acetylcholinesterase inhibitors, interacting with the enzyme as their primary target, are applied as relevant drugs and toxins. This review presents an overview of toxicology and pharmacology of reversible and irreversible acetylcholinesterase inactivating compounds. In the case of reversible inhibitors being commonly applied in neurodegenerative disorders treatment, special attention is paid to currently approved drugs (donepezil, rivastigmine and galantamine) in the pharmacotherapy of Alzheimer's disease, and toxic carbamates used as pesticides. Subsequently, mechanism of irreversible acetylcholinesterase inhibition induced by organophosphorus compounds (insecticides and nerve agents), and their specific and nonspecific toxic effects are described, as well as irreversible inhibitors having pharmacological implementation. In addition, the pharmacological treatment of intoxication caused by organophosphates is presented, with emphasis on oxime reactivators of the inhibited enzyme activity administering as causal drugs after the poisoning. Besides, organophosphorus and carbamate insecticides can be detoxified in mammals through enzymatic hydrolysis before they reach targets in the nervous system. Carboxylesterases most effectively decompose carbamates, whereas the most successful route of organophosphates detoxification is their degradation by corresponding phosphotriesterases.

Racial and ethnic disparities in Alzheimer's disease pharmacotherapy exposure: an analysis across four state Medicaid populations

BACKGROUND

Treatment disparities in Alzheimer's disease (AD) have received little attention. Determining whether disparities exist in this subpopulation is an important health policy issue.

OBJECTIVE

The aim was to determine whether an association existed between race/ethnicity and exposure to AD pharmacotherapy across 4 state Medicaid populations.

METHODS

Data from the Centers for Medicare and Medicaid Services (CMS) were used in this retrospective study. Persons with AD enrolled in California, Florida, New Jersey, or New York Medicaid programs on January 1, 2004, and remained in that program for 1 year. Individuals had an AD diagnosis based on the ICD-9-CM code 331.0. Outcomes of interest were exposure to a cholinesterase inhibitor (ChEI) or memantine. Multivariate logistic regression was used to test for the association between race/ethnicity and exposure to a ChEI or memantine. Variables of interest included demographic characteristics and resource utilization factors. The Oaxaca-Blinder decomposition method was used to test for disparities to determine whether exposure to AD pharmacotherapy was influenced by race.

RESULTS

Race, age, long-term care admittance, inpatient care admittance, state of residence, and sex were significant predictors of AD pharmacotherapy exposure (P < 0.0001 for all variables). Racial/ethnic disparities were observed with respect to exposure to a ChEI or memantine between non-Hispanic whites and Hispanics (in favor of Hispanics) in Florida (P < 0.0001), between non-Hispanic blacks and Hispanics (in favor of Hispanics) in California (P < 0.0001) and Florida (P < 0.0001), between non-Hispanic blacks and non-Hispanic others (in favor of non-Hispanic others) in California (P < 0.0001) and New York (P < 0.0001), and between Hispanics and non-Hispanic others (in favor of non-Hispanic others) in California (P = 0.001) and New York (P < 0.0001).

CONCLUSIONS

Disparities in AD pharmacotherapy exposure among minority populations are just as prevalent, if not of greater magnitude, than minority/white disparities.

A review of butyrylcholinesterase as a therapeutic target in the treatment of Alzheimer's disease

OBJECTIVE

To examine the role of butyrylcholinesterase (BuChE) in cholinergic signaling and neurologic conditions, such as Alzheimer's disease (AD). The rationale for inhibiting cholinesterases in the management of AD, including clinical evidence supporting use of the dual acetylcholinesterase (AChE) and BuChE inhibitor rivastigmine, is discussed.

DATA SOURCES

PubMed searches were performed using butyrylcholinesterase as a keyword. English-language articles referenced in PubMed as of September 2011 were included. Study Selection and Data Synthesis: English-language articles related to BuChE considered to be of clinical relevance to physicians were included. English-language articles specifically related to AChE were not included, as the role of AChE in cholinergic signaling and the underlying pathology of AD is well documented. Reference lists of included publications were used to supplement the search.

RESULTS

AChE and BuChE play a role in cholinergic signaling; BuChE can hydrolyze acetylcholine and compensate for AChE when levels are depleted. In the AD brain, AChE levels decrease, while BuChE levels are reportedly increased or unchanged, with changes becoming more pronounced during the disease course. Furthermore, BuChE genotype may influence AD risk and rate of disease progression. Strategies that increase acetylcholine levels (eg, cholinesterase inhibitors) demonstrate symptomatic efficacy in AD. Rivastigmine has proven cognitive efficacy in clinical trials, and data suggest that its action is mediated, in part, by inhibition of BuChE. Retrospective analyses of clinical trials provide evidence that BuChE genotype may also influence treatment response.

CONCLUSIONS

AChE-selective inhibitors and a dual AChE and BuChE inhibitor demonstrate symptomatic efficacy in AD. Mounting preclinical and clinical evidence for a role of BuChE in maintaining normal cholinergic function and the pathology of AD provides a rationale for further studies investigating use of rivastigmine in AD and the influence of BuChE genotype on observed efficacy.

Management of patients with Alzheimer's disease: pharmacological treatment and quality of life

A methodological approach to quality of life (QoL) assessment in Alzheimer's disease (AD) is challenging and few clinical trials have included it among outcomes, with conflicting results. In this review an indirect appraisal of evidence has been performed, searching the literature for the effect of drug treatments on determinants of QoL in AD. Among clinical factors associated with QoL, possible targets of drugs include cognition, which seems to be associated with QoL in early disease and can be positively affected by cholinesterase inhibitors (CIs) in this stage; functional decline, the risk of which can be decreased by CIs and memantine (MEM); behavioral and psychological symptoms, which can be reduced by MEM and atypical antipsychotics. Long-term observational studies have associated CIs and MEM treatment with a reduced institutionalization risk. According to the evidence, drug treatment of depression associated with AD should not be first choice from a QoL perspective, while treatment of pain can have beneficial effects on wellbeing indicators also in the late stages of the disease. Possible drug-related adverse events can affect QoL and should always be weighed against expected benefits from the patient's perspective. For this reason antipsychotic treatment is often problematic in AD and should be limited to severe psychosis and aggression, using the lowest effective doses for the shortest possible period. Conversely titration of CIs is necessary to reach the most effective dosages, although dose-related risk of adverse events has to be taken into account. Finally, CIs and MEM have been shown to reduce caregiver burden in randomized trials, possibly affecting caregivers' QoL.

Alzheimer's Disease: Differences of Transdermal versus Oral Treatment on Caregiving Time

Background

Data on indirect effects of dementia treatment on caregiver burden obtained from naturalistic studies are still lacking. We explored differences between patients with oral and transdermal application of acetylcholine esterase inhibitors regarding caregiver's time burden and psychopathology.

Methods

A cross-sectional naturalistic cohort study of 403 patients in outpatient care with three treatment groups (none, oral, and transdermal) was conducted. Assessments included a standardized clinical burden questionnaire and a standardized caregiver interview.

Results

Any treatment was associated with lower burden in most measures. Transdermal treatment was superior regarding (1) administration time (p < 0.001); (2) rates of administration problems (p = 0.031); (3) burden in activities of daily living (p = 0.008), and (4) caregiver anxiety (OR 0.25; 95% CI 0.05–0.99). Caregivers did not report better quality of life regarding mental/physical health. Physicians’ and caregivers’ ratings of patients’ improvements were not associated (κ = 0.01–0.06).

Conclusions

Benefits associated with transdermal treatment do not translate into a better ‘generic quality of life’ of the caregiver. The substantially different perceptions of patients’ improvements need to be considered in future studies.

Randomised multicentre trial on safety and efficacy of rivastigmine in cognitively impaired multiple sclerosis patients

BACKGROUND

Cognitive decline has been recognised as a frequent symptom in multiple sclerosis (MS). Cholinesterase inhibitors (ChEIs) are employed for the treatment of Alzheimer's disease, but there is some evidence that ChEIs might also be effective in MS patients with cognitive deficits, particularly deficits of memory function.

OBJECTIVE

The aim of this study was to evaluate efficacy on memory function and safety of the ChEI rivastigmine in MS patients with cognitive deficits as measured by the change from baseline of the total recall score of the selective reminding test (SRT) after 16 weeks of treatment.

METHODS

Efficacy and safety of rivastigmine were analysed in a 16-week, multicentre, double-blind, randomised, placebo-controlled study, followed by an optional one-year open-label treatment phase. Effects of rivastigmine and placebo were compared by an analysis of covariance.

RESULTS

In total, 86 patients were enrolled. Patients who received rivastigmine (n = 43) showed a non-significant increase in total recall score (sum of all words immediately recalled over all six trials) over placebo (n = 38) after 16 weeks of treatment (p = 0.2576). Other outcome measures provided no evidence supporting benefits of rivastigmine. Treatment with rivastigmine was well tolerated.

CONCLUSIONS

With the results of this study, the need for an effective therapy in cognitively impaired MS patients is still required. Thus, intensive and continued clinical research is required to explore therapeutic options for cognitive deficits in MS patients.

Compliance and Caregiver Satisfaction in Alzheimer's Disease: Results from the AXEPT Study

Background/Aims

According to experimental data, a transdermal application is preferred by caregivers of Alzheimer's disease (AD) patients compared with oral medications. The AXEPT study compared compliance to treatment among community-dwelling patients with mild-to-moderate AD treated with transdermal application compared to oral medications and caregiver satisfaction in a real clinical setting.

Methods

Data from 45 memory clinics in Italy were collected between September 8, 2010 and January 31, 2011. Compliance to treatment and caregiver satisfaction were measured using the Caregiver Medication Interview.

Results

A total of 855 AD patients and their caregivers participated in the study. Nearly 80% of caregivers of patients on patch were not concerned about adherence to treatment compared with 64% of caregivers of patients on oral drugs. Among caregivers of patients on patch, 94% did not report any difficulties in remembering to administer treatment compared with 73% of caregivers of patients on oral medications. The highest level of compliance and satisfaction was reported by caregivers of patients on transdermal application.

Conclusion

Caregivers of patients treated with a transdermal application appeared to be more satisfied and reported a higher level of compliance than caregivers of patients receiving anti-AD oral medications.

Cholinesterase inhibitors for mild cognitive impairment

BACKGROUND

Mild cognitive impairment is hypothesised to represent a pre-clinical stage of dementia but forms a heterogeneous group with variable prognosis.

OBJECTIVES

To assess the safety and efficacy of cholinesterase inhibitors in people with mild cognitive impairment.

SEARCH METHODS

Trials were identified from the Cochrane Dementia and Cognitive Improvement Group's Specialised Register, which is frequently updated from the major healthcare databases (MEDLINE, EMBASE, CINAHL, PsycINFO and Lilacs) as well as trial registers and grey literature.

SELECTION CRITERIA

Double-blind, placebo-controlled randomised trials of any cholinesterase inhibitor in people with mild cognitive impairment.

DATA COLLECTION AND ANALYSIS

Data were extracted from the published reports of the included studies, combined by meta-analysis where appropriate, and treatment efficacy and risk of adverse events were estimated.

MAIN RESULTS

Nine studies (from eight published reports) of 5149 individuals with mild cognitive impairment (however defined) were included in the review. Limited pooling of results was possible owing to different lengths of trials. Meta-analysis of the three studies reporting conversion to dementia gives no strong evidence of a beneficial effect of cholinesterase inhibitors on the progression to dementia at one, two or three years. The risk ratio (RR) for conversion at two years was significantly different from unity (0.67; 95% confidence interval (CI) 0.55 to 0.83), but this is based on only two studies reported in the same article. There was essentially no effect of cholinesterase inhibitors on cognitive test scores.Based on the results from 4207 individuals, there were significantly more adverse events in the cholinesterase inhibitor groups (RR 1.09; 95% CI 1.02 to 1.16), but no more serious adverse events or deaths. Gastrointestinal side effects were much more common (diarrhoea: RR 2.10; 95% CI 1.30 to 3.39; nausea: RR 2.97; 95% CI 2.57 to 3.42; vomiting: RR 4.42; 95% CI 3.23 to 6.05). Cardiac problems were no more likely in either group (RR 0.71; 95% CI 0.25 to 2.02). Other side effects reported significantly more often in the cholinesterase inhibitor group were muscle spasms/leg cramps (RR 7.52; 95% CI 4.34 to 13.02), headache (RR 1.34; 95% CI 1.05 to 1.71), syncope or dizziness (RR 1.62; 95% CI 1.36 to 1.93), insomnia (RR 1.66; 95% CI 1.36 to 2.02) and abnormal dreams (RR 4.25; 95% CI 2.57 to 7.04).

AUTHORS' CONCLUSIONS

There is very little evidence that cholinesterase inhibitors affect progression to dementia or cognitive test scores in mild cognitive impairment. This weak evidence is overwhelmed by the increased risk of adverse events, particularly gastrointestinal. Cholinesterase inhibitors should not be recommended for mild cognitive impairment.

Tau-targeted treatment strategies in Alzheimer's disease

With populations ageing worldwide, the need for treating and preventing diseases associated with high age is pertinent. Alzheimer's disease (AD) is reaching epidemic proportions, yet the currently available therapies are limited to a symptomatic relief, without halting the degenerative process that characterizes the AD brain. As in AD cholinergic neurons are lost at high numbers, the initial strategies were limited to the development of acetylcholinesterase inhibitors, and more recently the NMDA receptor antagonist memantine, in counteracting excitotoxicity. With the identification of the protein tau in intracellular neurofibrillary tangles and of the peptide amyloid-β (Aβ) in extracellular amyloid plaques in the AD brain, and a better understanding of their role in disease, newer strategies are emerging, which aim at either preventing their formation and deposition or at accelerating their clearance. Interestingly, what is well established to combat viral diseases in peripheral organs - vaccination - seems to work for the brain as well. Accordingly, immunization strategies targeting Aβ show efficacy in mice and to some degree also in humans. Even more surprising is the finding in mice that immunization strategies targeting tau, a protein that forms aggregates in nerve cells, ameliorates the tau-associated pathology. We are reviewing the literature and discuss what can be expected regarding the translation into clinical practice and how the findings can be extended to other neurodegenerative diseases with protein aggregation in brain.

[Pharmacological treatment of dementia: when, how and for how long. Recommendations of the Working Group on Dementia of the Catalan Society of Geriatrics and Gerontology]

Dementia in general--and Alzheimer's disease (AD) in particular--are bound to loom large among the most acute healthcare, social, and public health problems of the 21st century. AD shows a degenerative progression that can be slowed down--yet not halted--by today's most widely accepted specific treatments (those based on cholinesterase inhibitors as well as those using memantine). There is enough evidence to consider these treatments advisable for the mild, moderate and severe phases of the illness. However, in the final stage of the disease, a decision has to be made on whether to withdraw such treatment or not. In this paper, the Working Group on Dementia for the Catalan Society of Geriatrics and Gerontology reviews the use of these specific pharmacological treatments for AD, and, drawing on the scientific evidence thus gathered, makes a series of recommendations on when, how, and for how long, the currently existing specific pharmacological treatments should be used.

Neurogenic abnormalities in Alzheimer's disease differ between stages of neurogenesis and are partly related to cholinergic pathology

Neurogenesis occurs in the subventricular zone and the sub-granular layer of the hippocampus and is thought to take place in 5 stages, including proliferation, differentiation, migration, targeting, and integration phases, respectively. In Alzheimer's disease (AD) both increased and decreased neurogenesis has been reported and cholinergic activity is assumed to be involved in neurogenesis. The aim of this study was to systematically assess different phases of neurogenesis and their relation to AD and cholinergic pathology. We investigated post-mortem brain tissue from 20 AD patients and 21 non-demented controls that was neuropathologically characterized according to standardized criteria. Hippocampal sections were stained with antibodies against neurogenic markers Musashi-1, nestin, PSA-NCAM, doublecortin, and β-III-tubulin as well as ChAT (choline-acetyltransferase). Using image analysis immunoreactivity was assessed in the subventricular zone, the sub-granular layer, and the granule cell layer by determining the integrated optical density. In the sub-granular layer and the granule cell layer Musashi-1 and ChAT immunoreactivities were significantly lower in AD and decreased with increasing Braak stages. Conversely, immunorreactivities of both nestin and PSA-NCAM were significantly higher in AD and increased with increasing Braak stages while no changes were seen for doublecortin and β-III-tubulin, except for significantly higher doublecortin levels in the granule cell layer of AD cases. Of note, Musashi-1 immunoreactivity significantly correlated with ChAT immuonoreactivity across different Braak stages. In the subventricular zone only nestin immunoreactivity was significantly higher in AD and significantly increased with increasing Braak stages, while no significant differences were seen for all other markers. Our finding of a reduction of ChAT and Musashi-1 levels in AD is compatible with the assumption that cholinergic pathology per se has a detrimental influence on neurogenesis. We conclude that neurogenic abnormalities in AD differ between phases and areas of neurogenesis and stages of AD; while hippocampal stem cells (Musashi-1) decrease, proliferation (nestin) increases and differentiation/migration phase as well as axonal/dendritic targeting (doublecortin and β-III-tubulin) remains virtually unchanged. This suggests an attenuation of stem cells together with compensatory increased proliferation that, however, does not result in an increased number of migratory neuroblasts and differentiated neurons in AD.

Alzheimer's disease: a clinical practice-oriented review

Investigation in the field of Alzheimer's disease (AD), the commonest cause of dementia, has been very active in recent years and it may be difficult for the clinician to keep up with all the innovations and to be aware of the implications they have in clinical practice. The authors, thus, reviewed recent literature on the theme in order to provide the clinician with an updated overview, intended to support decision-making on aspects of diagnosis and management. This article begins to focus on the concept of AD and on its pathogenesis. Afterward, epidemiology and non-genetic risk factors are approached. Genetics, including genetic risk factors and guidelines for genetic testing, are mentioned next. Recommendations for diagnosis of AD, including recently proposed criteria, are then reviewed. Data on the variants of AD is presented. First approach to the patient is dealt with next, followed by neuropsychological evaluation. Biomarkers, namely magnetic resonance imaging, single photon emission tomography, FDG PET, PiB PET, CSF tau, and Aβ analysis, as well as available data on their diagnostic accuracy, are also discussed. Factors predicting rate of disease progression are briefly mentioned. Finally, non-pharmacological and pharmacological treatments, including established and emerging drugs, are addressed.

Ibogaine and the inhibition of acetylcholinesterase

ETHNOPHARMACOLOGICAL RELEVANCE

Ibogaine is a psychoactive monoterpine indole alkaloid extracted from the root bark of Tabernanthe iboga Baill. that is used globally in medical and nonmedical settings to treat drug and alcohol addiction, and is of interest as an ethnopharmacological prototype for experimental investigation and pharmaceutical development. The question of whether ibogaine inhibits acetylcholinesterase (AChE) is of pharmacological and toxicological significance.

MATERIALS AND METHODS

AChE activity was evaluated utilizing reaction with Ellman's reagent with physostigmine as a control.

RESULTS

Ibogaine inhibited AChE with an IC(50) of 520±40 μM.

CONCLUSIONS

Ibogaine's inhibition of AChE is physiologically negligible, and does not appear to account for observations of functional effects in animals and humans that might otherwise suggest the possible involvement of pathways linked to muscarinic acetylcholine transmission.

Effects of cholinesterase inhibitors on postoperative outcomes of older adults with dementia undergoing hip fracture surgery

OBJECTIVES

Cholinesterase inhibitors (ChEIs) may interact with muscle relaxants given during general anesthesia (GA), increasing the risk of postoperative complications. We evaluated the effects of ChEIs on the postoperative outcomes of older adults who underwent hip fracture surgery.

DESIGN

Population-based cohort study using linked administrative databases.

PARTICIPANTS

All individuals with dementia age 66 years or older, who underwent hip fracture surgery between April 1, 2003, and December 31, 2007, in Ontario, Canada.

EXPOSURES

Use of any ChEI (donepezil, rivastigmine, or galantamine) before surgery.

OUTCOMES

The primary composite outcome included any of the following: 30-day postoperative mortality; intensive care unit admissions; or in-hospital resuscitation. Secondary outcomes included postoperative respiratory failure and pneumonia.

ANALYSIS

We stratified the study sample on the basis of residence (community or long-term care [LTC]) and type of anesthetic (general or regional) to create four residence/anesthesia groups. We used propensity scores to match users and nonusers of ChEIs within the residence/anesthesia strata. We then calculated the relative risks (RR) and 95% confidence intervals (CI) for outcomes associated with ChEIs in the matched groups.

RESULTS

A total of 624 pairs of individuals from the community and 725 pairs from LTC were created among individuals who received GA. High rates of postoperative mortality and complications were observed in both ChEI users and nonusers. The RR of the primary outcome associated with ChEI use for individuals receiving GA was 0.88 (95% CI: 0.68-1.16; χ2 = 0.93; df = 1; p = 0.34) and 0.82 (95% CI: 0.63-1.04; χ2 = 2.59; df = 1; p = 0.11) in the community and LTC groups, respectively. In addition, ChEIs were not associated with any significant increased risk of postoperative respiratory complications.

CONCLUSIONS

ChEI use was not associated with an increased risk of postoperative complications among older adults with dementia who underwent hip fracture surgery. However, the poor postoperative outcomes overall reinforced the need to prevent fractures and improve outcomes in this population.

Noninvasive brain stimulation in Alzheimer's disease: systematic review and perspectives for the future

BACKGROUND

A number of studies have applied transcranial magnetic stimulation (TMS) to physiologically characterize Alzheimer's disease (AD) and to monitor effects of pharmacological agents, while others have begun to therapeutically use TMS and transcranial direct current stimulation (tDCS) to improve cognitive function in AD. These applications are still very early in development, but offer the opportunity of learning from them for future development.

METHODS

We performed a systematic search of all studies using noninvasive stimulation in AD and reviewed all 29 identified articles. Twenty-four focused on measures of motor cortical reactivity and (local) plasticity and functional connectivity, with eight of these studies assessing also effects of pharmacological agents. Five studies focused on the enhancement of cognitive function in AD.

RESULTS

Short-latency afferent inhibition (SAI) and resting motor threshold are significantly reduced in AD patients as compared to healthy elders. Results on other measures of cortical reactivity, e.g. intracortical inhibition (ICI), are more divergent. Acetylcholine-esterase inhibitors and dopaminergic drugs may increase SAI and ICI in AD. Motor cortical plasticity and connectivity are impaired in AD. TMS/tDCS can induce acute and short-duration beneficial effects on cognitive function, but the therapeutic clinical significance in AD is unclear. Safety of TMS/tDCS is supported by studies to date.

CONCLUSIONS

TMS/tDCS appears safe in AD, but longer-term risks have been insufficiently considered. TMS holds promise as a physiologic biomarker in AD to identify therapeutic targets and monitor pharmacologic effects. In addition, TMS/tDCS may have therapeutic utility in AD, though the evidence is still very preliminary and cautious interpretation is warranted.

Pre- and post-synaptic cortical cholinergic deficits are proportional to amyloid plaque presence and density at preclinical stages of Alzheimer's disease

Amyloid imaging has identified cognitively normal older people with plaques as a group possibly at increased risk for developing Alzheimer's disease-related dementia. It is important to begin to thoroughly characterize this group so that preventative therapies might be tested. Existing cholinotropic agents are a logical choice for preventative therapy as experimental evidence suggests that they are anti-amyloidogenic and clinical trials have shown that they delay progression of mild cognitive impairment to dementia. A detailed understanding of the status of the cortical cholinergic system in preclinical AD is still lacking, however. For more than 30 years, depletion of the cortical cholinergic system has been known to be one of the characteristic features of AD. Reports to date have suggested that some cholinergic markers are altered prior to cognitive impairment while others may show changes only at later stages of dementia. These studies have generally been limited by relatively small sample sizes, long postmortem intervals and insufficient definition of control and AD subjects by the defining histopathology. We, therefore, examined pre- and post-synaptic elements of the cortical cholinergic system in frontal and parietal cortex in 87 deceased subjects, including non-demented elderly with and without amyloid plaques as well as demented persons with neuropathologically confirmed AD. Choline acetyltransferase (ChAT) activity was used as a presynaptic marker while displacement of (3)H-pirenzepine binding by oxotremorine-M in the presence and absence of GppNHp was used to assess postsynaptic M1 receptor coupling. The results indicate that cortical ChAT activity as well as M1 receptor coupling are both significantly decreased in non-demented elderly subjects with amyloid plaques and are more pronounced in subjects with AD and dementia. These findings confirm that cortical cholinergic dysfunction in AD begins at the preclinical stage of disease and suggest that cholinotropic agents currently used for AD treatment are a logical choice for preventative therapy.

Dementia medications and risk of falls, syncope, and related adverse events: meta-analysis of randomized controlled trials

OBJECTIVES

To evaluate the effect of cholinesterase inhibitors (ChEIs) and memantine on the risk of falls, syncope, and related events, defined as fracture and accidental injury.

DESIGN

Meta-analysis of randomized controlled trials that were identified from MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (no language restriction, through July 2009), and manual search.

SETTING

Community and nursing homes.

PARTICIPANTS

Participants in fifty-four placebo-controlled randomized trials and extension studies of ChEIs and memantine that reported falls, syncope, and related events in cognitively impaired older adults.

MEASUREMENTS

Falls, syncope, fracture, and accidental injury.

RESULTS

ChEI use was associated with greater risk of syncope (odds ratio (OR)=1.53, 95% confidence interval (CI)=1.02-2.30) than placebo but not with other events (falls: OR=0.88, 95% CI=0.74-1.04; fracture: OR=1.39, 95% CI=0.75-2.56; accidental injury: OR=1.13, 95% CI=0.87-1.45). Memantine use was associated with fewer fractures (OR=0.21, 95% CI=0.05-0.85) but not with other events (falls: OR=0.92, 95% CI=0.72-1.18; syncope: OR=1.04, 95% CI=0.35-3.04; accidental injury: OR=0.80, 95% CI=0.56-1.12). There was no differential effect according to type and severity of cognitive impairment, residential status, or length of follow-up, although because of underreporting and small number of events, a potential benefit or risk cannot be excluded.

CONCLUSION

ChEIs may increase the risk of syncope, with no effects on falls, fracture, or accidental injury in cognitively impaired older adults. Memantine may have a favorable effect on fracture, with no effects on other events. More research is needed to confirm the reduction in fractures observed for memantine.