The effect of memantine on sleep architecture and psychiatric symptoms in patients with Alzheimer's disease

Association of Sleep Disturbances With Brain Amyloid and Tau Burden, Cortical Atrophy, and Cognitive Dysfunction Across the AD Continuum

BACKGROUND AND OBJECTIVES

Patients with Alzheimer disease (AD) frequently suffer from various sleep disturbances. However, how sleep disturbance is associated with AD and its progression remains poorly investigated. We investigated the association of total sleep time with brain amyloid and tau burden, cortical atrophy, cognitive dysfunction, and their longitudinal changes in the AD spectrum.

METHODS

In this retrospective cohort study, we enrolled participants on the AD spectrum who were positive on 18F-florbetaben (FBB) PET. All participants underwent the Pittsburgh Sleep Quality Index, brain MRI, FBB PET, 18F-flortaucipir (FTP) PET, and detailed neuropsychological testing. In addition, a subset of participants completed follow-up assessments. We analyzed the association of total sleep time with the baseline and longitudinal FBB-standardized uptake value ratio (SUVR), FTP-SUVR, cortical thickness, and cognitive domain composite scores.

RESULTS

We examined 138 participants on the AD spectrum (15 with preclinical AD, 62 with prodromal AD, and 61 with AD dementia; mean age 73.4 ± 8.0 years; female 58.7%). Total sleep time was longer in the AD dementia group (7.4 ± 1.6 hours) compared with the preclinical (6.5 ± 1.4 hours; p = 0.026) and prodromal groups (6.6 ± 1.4 hours; p = 0.001), whereas other sleep parameters did not differ between groups. Longer total sleep time was not associated with amyloid accumulation but rather with tau accumulation, especially in the amygdala, hippocampus, basal forebrain, insular, cingulate, occipital, inferior temporal cortices, and precuneus. Longer total sleep time predicted faster tau accumulation in Braak regions V-VI (β = 0.016, p = 0.007) and disease progression to mild cognitive impairment or dementia (hazard ratio = 1.554, p = 0.024). Longer total sleep time was also associated with memory deficit (β = -0.19, p = 0.008).

DISCUSSION

Prolonged total sleep time was associated with tau accumulation in sleep-related cortical and subcortical areas as well as memory dysfunction. It also predicted faster disease progression with tau accumulation. Our study highlights the clinical importance of assessing total sleep time as a marker for disease severity and prognosis in the AD spectrum.

Cholinergic Antagonists and Behavioral Disturbances in Neurodegenerative Diseases

Cholinergic antagonists interfere with synaptic transmission in the central nervous system and are involved in pathological processes in patients with neurocognitive disorders (NCD), such as behavioral and psychological symptoms of dementia (BPSD). In this commentary, we will briefly review the current knowledge on the impact of cholinergic burden on BPSD in persons with NCD, including the main pathophysiological mechanisms. Given the lack of clear consensus regarding symptomatic management of BPSD, special attention must be paid to this preventable, iatrogenic condition in patients with NCD, and de-prescription of cholinergic antagonists should be considered in patients with BPSD.

Effects of memantine on mania-like phenotypes exhibited by Drosophila Shaker mutants

INTRODUCTION

Increased glutamate levels and electrolytic fluctuations have been observed in acutely manic patients. Despite some efficacy of the non-competitive NMDA receptor antagonist memantine (Mem), such as antidepressant-like and mood-stabilizer drugs in clinical studies, its specific mechanisms of action are still uncertain. The present study aims to better characterize the Drosophila melanogaster fly Shaker mutants (SH), as a translational model of manic episodes within bipolar disorder in humans, and to investigate the potential anti-manic properties of Mem.

METHODS AND RESULTS

Our findings showed typical behavioral abnormalities in SH, which mirrored with the overexpression of NMDAR-NR1 protein subunit, matched well to glutamate up-regulation. Such molecular features were associated to a significant reduction of SH brain volume in comparison to Wild Type strain flies (WT). Here we report on the ability of Mem treatment to ameliorate behavioral aberrations of SH (similar to that of Lithium), and its ability to reduce NMDAR-NR1 over-expression.

CONCLUSIONS

Our results show the involvement of the glutamatergic system in the SH, given the interaction between the Shaker channel and the NMDA receptor, suggesting this model as a promising tool for studying the neurobiology of bipolar disorders. Moreover, our results show Mem as a potential disease-modifying therapy, providing insight on new mechanisms of action.

Challenges and approaches of drugs such as Memantine, Donepezil, Rivastigmine and Aducanumab in the treatment, control and management of Alzheimer's disease

Alzheimer's disease (AD) is a kinds of neuropsychiatric illnesses that affect the central nervous system. In this disease, the accumulation of amyloid-beta increases, and phosphorylated tau (P-tau) protein, one of the ways to treat this disease is to reduce the accumulation of amyloid-beta. Various studies have demonstrated that pharmacological approaches have considerable effects in the treatment of AD, despite the side effects and challenges. Cholinesterase inhibitors and the NMDA receptor antagonist memantine are presently authorized therapies for AD. Memantine and Donepezil are the most common drugs for the prevention and therapy of AD with mechanisms such as lessened β-amyloid plaque, effect on N-Methyl-D-aspartate (NMDA) receptors. Diminution glutamate and elevated acetylcholine are some of the influences of medications administrated to treat AD, and drugs can also play a role in slowing the progression of cognitive and memory impairment. A new pharmacological approach and strategy is required to control the future of AD. This review appraises the effects of memantine, donepezil, rivastigmine, and aducanumab in clinical trials, in vitro and animal model studies that have explored how these drugs versus AD development and also discuss possible mechanisms of influence on the brain. Research in clinical trials has substantial findings that support the role of these medications in AD treatment and ameliorate the safety and efficacy of AD therapy, although more clinical trials are required to prove their effectiveness.

Burden of Insomnia and Sleep Disturbances and the Impact of Sleep Treatments in Patients with Probable or Possible Alzheimer's Disease: A Structured Literature Review

Background:

Sleep disturbances are frequent in Alzheimer’s disease (AD).

Objective:

To summarize the impact of sleep disturbances on AD patients and their caregivers and the effects of currently available sleep therapies.

Methods:

Published studies (January 1985–March 2020) assessing the burden associated with insomnia/sleep disturbances in the AD population and insomnia treatment effects were identified by searching PubMed, Embase, and Cochrane Library and screened against inclusion criteria.

Results:

58 studies assessing patient and caregiver burden, institutionalization, and insomnia treatments in AD patients with sleep disturbances were identified. Sleep disturbances were associated with worse cognition, functional ability, and behavioral and neuropsychological functioning. Health status and quality of life of both patients and caregivers were reduced in the presence of sleep disturbances. Sleep disturbances were also associated with institutionalization. Although significant associations between sleep problems and clinical outcomes were apparent, there was generally no control for other influencing factors (e.g., cognitive status). Bright light and behavioral therapies as well as drugs showed some promise in AD patients, but studies were primarily small and limited data were available, particularly in regard to the effect on associated clinical burden.

Conclusion:

Sleep disturbances are a significant problem for AD patients and caregivers, associated with behavioral and psychological problems and cognitive decline. However, they remain poorly characterized and under-researched. As the global population is aging and AD is on thes rise, data from larger, prospective trials are required to fully understand the clinical correlates of sleep disturbances and the impact insomnia treatments can have.

Impact of Pharmacotherapy on Insomnia in Patients with Alzheimer's Disease

Insomnia is a pervasive sleep disorder affecting numerous patients across diverse demographical populations and comorbid disease states. Contributing factors are often a complex interaction of biological, psychological, and social components, requiring a multifaceted approach in terms of both diagnosis and management. In the setting of Alzheimer’s disease, insomnia is an even more complicated issue, with a higher overall prevalence than in the general population, greater complexity of contributing etiologies, and differences in diagnosis (at times based on caregiver observation of sleep disruption rather than subjective complaints by the individual with the disorder), and requiring more discretion in terms of treatment, particularly in regard to adverse effect profile concerns. There also is growing evidence of the bidirectional nature of sleep disruption and Alzheimer’s disease, with insomnia potentially contributing to disease progression, making the condition even more paramount to address. The objective of this review was to provide the clinician with an overview of treatment strategies that may have value in the treatment of disturbed sleep in Alzheimer’s disease. Nonpharmacological approaches to treatment should be exhausted foremost; however, pharmacotherapy may be needed in certain clinical scenarios, which can be a challenge for clinicians given the paucity of evidence and guidelines for treatment in the subpopulation of Alzheimer’s disease. Agents such as sedating antidepressants, melatonin, and site-specific γ-aminobutyric acid agonists are often employed based on historical usage but are not necessarily supported by high-quality trials. Newer agents such as dual orexin receptor antagonists have demonstrated some promise but still need further evaluation.

The Development of Pharmacological Therapies for Alzheimer's Disease

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder that currently has no cure. The aged population is growing globally, creating an urgent need for more promising therapies for this debilitating disease. Much effort has been made in recent decades, and the field is highly dynamic, with numerous trials. The main focus of these trials includes disease modification and symptomatic treatment. Some have shown beneficial outcomes, while others have shown no significant benefits. Here, we cover the outcome of recently published AD clinical trials, as well as the mechanism of action of these therapeutical agents, to re-think drug development strategies and directions for future studies.

Cellular Effects of Rhynchophylline and Relevance to Sleep Regulation

Uncaria rhynchophylla is a plant highly used in the traditional Chinese and Japanese medicines. It has numerous health benefits, which are often attributed to its alkaloid components. Recent studies in humans show that drugs containing Uncaria ameliorate sleep quality and increase sleep time, both in physiological and pathological conditions. Rhynchophylline (Rhy) is one of the principal alkaloids in Uncaria species. Although treatment with Rhy alone has not been tested in humans, observations in rodents show that Rhy increases sleep time. However, the mechanisms by which Rhy could modulate sleep have not been comprehensively described. In this review, we are highlighting cellular pathways that are shown to be targeted by Rhy and which are also known for their implications in the regulation of wakefulness and sleep. We conclude that Rhy can impact sleep through mechanisms involving ion channels, N-methyl-d-aspartate (NMDA) receptors, tyrosine kinase receptors, extracellular signal-regulated kinases (ERK)/mitogen-activated protein kinases (MAPK), phosphoinositide 3-kinase (PI3K)/RAC serine/threonine-protein kinase (AKT), and nuclear factor-kappa B (NF-κB) pathways. In modulating multiple cellular responses, Rhy impacts neuronal communication in a way that could have substantial effects on sleep phenotypes. Thus, understanding the mechanisms of action of Rhy will have implications for sleep pharmacology.

The Treatment of Sleep Dysfunction in Neurodegenerative Disorders

Sleep dysfunction is highly prevalent across the spectrum of neurodegenerative conditions and is a key determinant of quality of life for both patients and their families. Mounting recent evidence also suggests that such dysfunction exacerbates cognitive and affective clinical features of neurodegeneration, as well as disease progression through acceleration of pathogenic processes. Effective assessment and treatment of sleep dysfunction in neurodegeneration is therefore of paramount importance; yet robust therapeutic guidelines are lacking, owing in part to a historical paucity of effective treatments and trials. Here, we review the common sleep abnormalities evident in neurodegenerative disease states and evaluate the latest evidence for traditional and emerging interventions, both pharmacological and nonpharmacological. Interventions considered include conservative measures, targeted treatments of specific clinical sleep pathologies, established sedating and alerting agents, melatonin, and orexin antagonists, as well as bright light therapy, behavioral measures, and slow-wave sleep augmentation techniques. We conclude by providing a suggested framework for treatment based on contemporary evidence and highlight areas that may emerge as major therapeutic advances in the near future.

The Bidirectional Relationship Between Sleep and Inflammation Links Traumatic Brain Injury and Alzheimer's Disease

Traumatic brain injury (TBI) and Alzheimer's disease (AD) are diseases during which the fine-tuned autoregulation of the brain is lost. Despite the stark contrast in their causal mechanisms, both TBI and AD are conditions which elicit a neuroinflammatory response that is coupled with physical, cognitive, and affective symptoms. One commonly reported symptom in both TBI and AD patients is disturbed sleep. Sleep is regulated by circadian and homeostatic processes such that pathological inflammation may disrupt the chemical signaling required to maintain a healthy sleep profile. In this way, immune system activation can influence sleep physiology. Conversely, sleep disturbances can exacerbate symptoms or increase the risk of inflammatory/neurodegenerative diseases. Both TBI and AD are worsened by a chronic pro-inflammatory microenvironment which exacerbates symptoms and worsens clinical outcome. Herein, a positive feedback loop of chronic inflammation and sleep disturbances is initiated. In this review, the bidirectional relationship between sleep disturbances and inflammation is discussed, where chronic inflammation associated with TBI and AD can lead to sleep disturbances and exacerbated neuropathology. The role of microglia and cytokines in sleep disturbances associated with these diseases is highlighted. The proposed sleep and inflammation-mediated link between TBI and AD presents an opportunity for a multifaceted approach to clinical intervention.

Progress and perspectives of brain-targeting lipid-based nanosystems via the nasal route in Alzheimer's disease

Since health care systems dedicate substantial resources to Alzheimer's disease (AD), it poses an increasing challenge to scientists and health care providers worldwide, especially that many decades of research in the medical field revealed no optimal effective treatment for this disease. The intranasal administration route seems to be a preferable route of anti-AD drug delivery over the oral one as it demonstrates an ability to overcome the related obstacles reflected in low bioavailability, limited brain exposure and undesired pharmacokinetics or side effects. This delivery route can bypass the systemic circulation through the intraneuronal and extraneuronal pathways, providing truly needleless and direct brain drug delivery of the therapeutics due to its large surface area, porous endothelial membrane, the avoidance of the first-pass metabolism, and ready accessibility. Among the different nano-carrier systems developed, lipid-based nanosystems have become increasingly popular and have proven to be effective in managing the common symptoms of AD when administered via the nose-to-brain delivery route, which provides an answer to circumventing the BBB. The design of such lipid-based nanocarriers could be challenging since many factors can contribute to the quality of the final product. Hence, according to the authors, it is recommended to follow the quality by design methodology from the early stage of development to ensure high product quality while saving efforts and costs. This review article aims to draw attention to the up-to-date findings in the field of lipid-based nanosystems and the potential role of developing such forms in the management of AD by means of the nose-to-brain delivery route, in addition to highlighting the significant role of applying QbD methodology in this development.

A manual-based intervention for carers of people with dementia and sleep disturbances: an acceptability and feasibility RCT

BACKGROUND

It has been estimated that between 25% and 40% of people living with dementia suffer from sleep disturbances, and there are currently no known effective treatments. Sleep disturbances may be the direct result of dementia or due to other comorbidities, such as pain and limited mobility. If carers' sleep is also disturbed, carers too can become tired and stressed, and this sometimes results in the breakdown of care in the home.

OBJECTIVES

To design an evidence-based manualised non-pharmacological therapy for sleep disturbances and test it for feasibility and acceptability.

DESIGN

A single-blind, randomised, parallel-group feasibility trial, with participants randomised 2 : 1 to intervention or treatment as usual (TAU).

SETTING

Five memory services in two London NHS trusts and Join Dementia Research (JDR).

PARTICIPANTS

The study recruited people with dementia and sleep disturbances (who scored ≥ 4 on at least one question on the Sleep Disorders Inventory) and their primary family carers.

INTERVENTION

All participants were given an Actiwatch (CamNtech Ltd, Cambridge, UK) to wear to record their sleep patterns for 2 weeks before randomisation. The intervention group received Dementia RElAted Manual for Sleep; STrAtegies for RelaTives (DREAMS START). This was designed as a six-session, manual-based intervention for carers of people with dementia, delivered by trained and clinically supervised psychology graduates, based on evidence about managing sleep disturbance in people with dementia. It uses the structure of a previous manual-based treatment, STrAtegies for RelaTives (START). Family carers were consulted about structure, content and design. Sessions were interactive, and each involved techniques, tasks to practise between sessions, relaxation and a recapitulation on the previous session. The sessions covered understanding sleep and dementia, making a plan (incorporating information from Actiwatch read-outs and a light box to increase light), daytime activity and routine, difficult night-time behaviours, taking care of your own (carer's) sleep and using the strategies in the future. Carers kept their own manual, light box and relaxation recordings post intervention.

RANDOMISATION AND BLINDING

A statistician created an electronic randomisation list, stratified by site, using random permuted blocks. Those assessing the outcome were blinded to allocation; participants were not blinded.

MAIN OUTCOME MEASURES

Outcomes were assessed at 3 months. (1) Feasibility, defined as the percentage of eligible people who consented to the study recruitment, with an expected value of 50% [95% confidence interval (CI) 41% to 59%]. (2) Acceptability, defined as the percentage of intervention group participants attending ≥ 4 intervention sessions, with an expected value of 75% (95% CI 59% to 87%). The predetermined criterion for progression to the main trial was acceptability of ≥ 70%.

RESULTS

Of 95 eligible patients referred, 63 (66%, 95% CI 56% to 76%) consented between 4 August 2016 and 24 March 2017: 61 from memory clinics and two from JDR. Of these, 62 participants (65%, 95% CI 55% to 75%) were randomised: 42 to the intervention arm and 20 to the TAU arm. Thirty-seven out of 42 participants (88%, 95% CI 75% to 96%) adhered to the intervention.

CONCLUSIONS

The results show that the randomised controlled trial is feasible and that the intervention is acceptable. A higher than expected proportion of eligible patients referred consented to the study and adhered to the intervention.

LIMITATIONS

Participants were not blinded and were recruited only in London.

FUTURE WORK

The results of this trial indicate that a future efficacy trial is warranted.

TRIAL REGISTRATION

Current Controlled Trials ISCTRN36983298.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 22, No. 71. See the NIHR Journals Library website for further project information. Funding was also provided by Camden and Islington NHS Foundation Trust and Barnet, Enfield and Haringey Mental Health NHS Trust to pay for excess treatment costs from therapist training and supervision and intervention delivery.

The management of sleep disorders in dementia: an update

PURPOSE OF REVIEW

Sleep disorders in dementia cause distress and may lead to families being unable to care for someone with dementia at home. Recent Cochrane reviews found no interventions of proven effectiveness. There was no effect of light therapy and moderate evidence that melatonin was ineffective both given without knowledge of the patient's circadian rhythm. The current article updates this review by considering newer publications on interventions for sleep disorders or abnormalities of the sleep-wake cycle in people with dementia living in the community.

RECENT FINDINGS

We searched electronically for new primary research, reviews and meta-analyses and identified 258 articles published between 15/12/2015 and 14/06/2017 on sleep and dementia; 43 of them on nonpharmacological or pharmacological treatments. Fifteen articles reported on the management of sleep disturbances in people with dementia, living at home. Those using pharmacological treatments (melatonin, psychotropic medications, donepezil, memantine) encompassed a meta-analysis, two double-blind RCTs, two uncontrolled trials, two population-based studies, and one case report. The studies of behavioural interventions comprised five uncontrolled trials, one case series, and one qualitative study. We also included three recent reviews on the management of sleep disturbances in Alzheimer's disease; pharmacotherapies for sleep disturbances in dementia, and dementia prevention, intervention and care. None of these found a treatment that showed definitive effectiveness, although there is preliminary work about nonpharmacological interventions, which can be built on.

SUMMARY

Clinically effective, safe treatment of sleep disturbances in dementia remains an unresolved challenge. Given the importance of sleep and the many consequences of its disruption, well designed controlled trials are needed to determine acceptable and cost-effective treatment strategies that work for sleep disturbances.