An update on the safety of current therapies for Alzheimer's disease: focus on rivastigmine

Association between Polypharmacy and Adverse Events in Patients with Alzheimer's Disease: An Analysis of the Japanese Adverse Drug Event Report Database (JADER)

Background and Objectives: Alzheimer's disease is a global health concern, with a rising prevalence among the elderly. Current pharmacological treatments, including acetylcholinesterase inhibitors (AChEIs) and N-Methyl D-Aspartate (NMDA) receptor antagonists, are associated with adverse events (AEs), particularly in the context of polypharmacy. This study aimed to investigate the relationship between Alzheimer's disease treatment combinations, the number of concomitant medications, and the occurrence of AEs. Materials and Methods: Data from the Japanese Adverse Drug Event Report database, spanning from April 2004 to June 2020, were analyzed. Patients aged 60 and older with Alzheimer's disease treated with AChEIs (donepezil, galantamine, and rivastigmine) or the NMDA receptor antagonist memantine were included. Logistic regression models were employed to assess the association between AEs and Alzheimer's disease drug combinations, as well as the number of concomitant medications. Results: Among 2653 patients, 47.7% were prescribed five or more drugs. The frequency of AEs was 6.4% for bradycardia, 4.6% for pneumonia, 3.6% for altered state of consciousness, 3.5% for seizures, 3.5% for decreased appetite, 3.5% for vomiting, 3.4% for loss of consciousness, 3.4% for fracture, 3.2% for cardiac failure, and 3.0% for falls. The combination of memantine with AChEIs was associated with a higher risk of bradycardia, whereas donepezil alone was linked to a reduced risk of fractures and falls. Polypharmacy was significantly correlated with an increased incidence of AEs, particularly altered state of consciousness, decreased appetite, vomiting, and falls. The adjusted odds ratios for using five or more drugs compared to no drugs was 10.45 for altered state of consciousness, 7.92 for decreased appetite, 4.74 for vomiting, and 5.95 for falls. Conclusions: In the treatment of Alzheimer's disease, the occurrence of AEs is associated with the number of concurrent medications, independently of the known AEs of Alzheimer's disease drugs and their combination patterns.

Investigating the effect of parasites (toxoplasma gondii RH strain, Leishmania major (MRHO/IR/75/ER), and hydatid cyst) antigens on Alzheimer's disease: An in vivo evaluation

This study aimed to investigate the effects of parasite antigens on Alzheimer's symptoms in animal model. Alzheimer's model was induced in Wistar rats using Amyloid-beta peptide, and treated with parasite crude antigens from T. gondii RH strain, L. major (MRHO/IR/75/ER), and HC. Spectrophotometry and real-time PCR were used to evaluate the oxidative stress levels, antioxidant enzyme activity, and gene expression of NLRP3, IL-8, IL-1β, and Caspase-1. Histological assays were performed to investigate structural changes in the hippocampus. Apoptosis was analyzed using an Annexin V Apoptosis by Flow cytometer. The levels of total oxidant, antioxidant, and SOD increased in the Alzheimer's group compared with the control group, but these factors were lower in the L. major group. The apoptosis in the treated groups was lower compared to the Alzheimer's group. IL-8 expression was significantly higher in all Alzheimer's groups, but decreased in the HC and L. major treated group compared to Alzheimer's. IL-1β and Caspase-1 expression were similarly increased in all groups compared with the control group, but decreased in the antigen-treated groups compared with Alzheimer's. NLRP3 expression was increased in all groups compared with the control group, with lower expression in HC group, but significantly decreased in L. major group compared with Alzheimer's. In histological results, only L. major group could play a therapeutic role in pathological damage of the hippocampus. The results showed that parasite antigens, specifically L. major antigens, may have neuroprotective effects that reduce oxidative stress, apoptosis, and histopathological changes in response to AD in animal model.

The Influence of an Acute Administration of Cannabidiol or Rivastigmine, Alone and in Combination, on Scopolamine-Provoked Memory Impairment in the Passive Avoidance Test in Mice

Memory is one of the most important abilities of our brain. The process of memory and learning is necessary for the proper existence of humans in the surrounding environment. However, sometimes there are unfavourable changes in the functioning of the brain and memory deficits occur, which may be associated with various diseases. Disturbances in the cholinergic system lead to abnormalities in memory functioning and are an essential part of clinical symptoms of many neurodegenerative diseases. However, their treatment is difficult and still unsatisfactory; thus, it is necessary to search for new drugs and their targets, being an alternative method of mono- or polypharmacotherapy. One of the possible strategies for the modulation of memory-related cognitive disorders is connected with the endocannabinoid system (ECS). The aim of the present study was to determine for the first time the effect of administration of natural cannabinoid compound (cannabidiol, CBD) and rivastigmine alone and in combination on the memory disorders connected with cholinergic dysfunctions in mice, provoked by using an antagonist of muscarinic cholinergic receptor-scopolamine. To assess and understand the memory-related effects in animals, we used the passive avoidance (PA) test, commonly used to examine the different stages of memory. An acute administration of CBD (1 mg/kg) or rivastigmine (0.5 mg/kg) significantly affected changes in scopolamine-induced disturbances in three different memory stages (acquisition, consolidation, and retrieval). Interestingly, co-administration of CBD (1 mg/kg) and rivastigmine (0.5 mg/kg) also attenuated memory impairment provoked by scopolamine (1 mg/kg) injection in the PA test in mice, but at a much greater extent than administered alone. The combination therapy of these two compounds, CBD and rivastigmine, appears to be more beneficial than substances administered alone in reducing scopolamine-induced cognitive impairment. This polytherapy seems to be favourable in the pharmacotherapy of various cognitive disorders, especially those in which cholinergic pathways are implicated.

Amyloid Targeting Red Emitting AIE Dots for Diagnostic and Therapeutic Application against Alzheimer's Disease

The emergence of neurodegenerative diseases is connected to several pathogenic factors, including metal ions, amyloidogenic proteins, and reactive oxygen species. Recent studies suggest that cytotoxicity is caused by the small, dynamic, and metastable nature of early stage oligomeric species. This work introduces a small molecule-based red-emitting probe with smart features such as increased reactivities against multiple targets, metal-free amyloid-β (Aβ), and metal-bound amyloid-β (Aβ), and most importantly, early stage oligomeric species which are associated with the most common and widespread type of dementia, Alzheimer's disease (AD). Theoretical analyses like molecular dynamics simulation and molecular docking were performed to confirm the reactivity of the molecule toward Aβ and found some excellent interactions between the molecule and the peptide. The in vitro and cellular studies demonstrated that this highly biocompatible molecule effectively reduces the structural damage to mitochondria while shielding cells from apoptosis, scavenges ROS (reactive oxygen species), and attenuates multifaceted amyloid toxicity.

Proton Pump Inhibitors and Cognitive Health: Review on Unraveling the Dementia Connection and Co-morbid Risks

Dementia, an international health issue distinguished by the impairment of daily functioning due to cognitive decline, currently affects more than 55 million people worldwide, with the majority residing in low-income and middle-income countries. Globally, dementia entails significant economic burdens in 2019, amounting to a cost of 1.3 trillion US dollars. Informal caregivers devote considerable hours to providing care for those affected. Dementia imposes a greater caregiving and disability-adjusted life-year burden on women. A recent study has established a correlation between prolonged Proton Pump Inhibitor (PPI) usage and dementia, in addition to other neurodegenerative conditions. PPIs are frequently prescribed to treat peptic ulcers and GERD (gastroesophageal reflux disease) by decreasing stomach acid secretion. They alleviate acid-related symptoms through the inhibition of acid-secreting H+-K+ ATPase. In a number of observational studies, cognitive decline and dementia in the elderly have been linked to the use of PPIs. The precise mechanism underlying this relationship is unknown. These drugs might also alter the pH of brain cells, resulting in the accumulation of amyloid-beta (Aβ) peptides and the development of Alzheimer's disease (AD). Despite the compelling evidence supporting the association of PPIs with dementia, the results of studies remain inconsistent. The absence of a correlation between PPI use and cognitive decline in some studies emphasizes the need for additional research. Chronic PPI use can conceal underlying conditions, including cancer, celiac disease, vitamin B12 deficiency, and renal injury, highlighting dementia risk and the need for further investigations on cognitive health.

Advances in Aβ imaging probes: a comprehensive study of radiolabelled 1,3-diaryl-2-propen-1-ones for Alzheimer's disease: a review

Alzheimer's disease (AD) is a formidable neurodegenerative disorder characterized by cognitive decline, memory impairment and inability to perform everyday tasks. In the pursuit of innovative diagnostic and therapeutic strategies, the synthesis and application of radiolabelled compounds have garnered significant attention. This review delves into the synthesis and biological significance of radiolabelled 1,3-diaryl-2-propen-1-ones, commonly known as chalcones, as Aβ imaging probes for AD. These versatile chalcone derivatives have demonstrated noteworthy potential as radiotracers for visualizing Aβ imaging probes, which are hallmark pathologies of AD. This review encompasses an exploration of chalcone synthesis via diverse methodologies and their biological implications, both as standalone entities and as precursors for intricate natural products. In addition, the pivotal role of advanced imaging techniques, such as single-photon emission computed tomography (SPECT) and positron emission tomography (PET), using various radioisotopes is highlighted. The use of radiopharmaceutical agents, including [18F]FDG, [18F]FMAPO, [11C]6-Me-BTA-1, [124/125I]IBETA, and [64Cu]YW-7 as potent tools for early diagnosis and therapeutic advancement is explored. This review underscores the critical nexus between radiolabelled chalcones and their pivotal role in advancing diagnostic and therapeutic paradigms in AD research. Furthermore, this study encapsulated the role of radiolabelled chalcone emphasizing their prospective implications for drug development and therapeutic interventions. A focal point of paramount significance is the elucidation of Aβ imaging probes and its important role in the combat against AD, with a particular emphasis on their role in facilitating early diagnosis and fostering advancements in therapeutic strategies.

Ethanol extract of Andrographis paniculata alleviates aluminum-induced neurotoxicity and cognitive impairment through regulating the p62-keap1-Nrf2 pathway

BACKGROUND

Alzheimer's disease (AD) is the most prevalent neurodegenerative and remains incurable. Aluminum is a potent neurotoxin associated with AD. The main pathological features of AD are extracellular amyloid-β protein deposition and intracellular hyperphosphorylated Tau protein. A body of evidence suggest that oxidative stress and autophagy are involved in the pathogenesis of AD. Andrographis paniculata (AP) is a native plant with anti-inflammatory, anti-oxidative stress, and regulation of autophagy properties. AP significantly alleviated cognitive impairments, reduced Aβ deposition and has neuroprotective effect. However, its effects on aluminum-induced AD model have not been studied much. In this study, we investigated whether AP protect against aluminum-induced neurotoxicity through regulation of p62-Kelch-like ECH-associated protein 1(Keap1)-Nuclear factor E2 related factor 2 (Nrf2) pathway and activation autophagy in vivo and in vitro.

METHODS

UPLC-ESI-qTOF-MS/MS was used to identify the chemical constituents of AP ethanol extract. The mice with cognitive deficit were established by injecting aluminum chloride and D-galactose, and treated with either AP extract (200, 400, or 600 mg/kg/d) or andrographolide (2 mg/kg/2d).The spatial memory ability was detected by Morris water maze, HE staining were used to detect in brain tissue,Oxidative stress indexs and SOD activity in both serum and brain tissue were detected by kit.The expression of p62-Nrf2 pathway proteins were measured via western blotting. Furthermore, the neurotoxicity model was induced by aluminum maltolate (700 µM) in PC12 cells. Following AP and andrographolide treatment, the cell viability was detected. The relevant mRNA and protein expressions were detected in cells transfected with the p62 siRNA.

RESULTS

The main active components of AP included andrographolide, neoandrographolide and deoxyandrographolide as identified. AP and andrographolide significantly improved the spatial memory ability of mice, attenuated pathological changes of hippocampal cells, reduced the level of malondialdehyde, and increased superoxide dismutase activity in serum or brain tissue as compared to model control. In addition, the Nrf2, p62 and LC3B-II proteins expression were increased, and p-Tau and Keap1 proteins were decreased in the hippocampus after AP and andrographolide treatment.Furthermore, AP increased aluminum maltolate-induced cell viability in PC12 cells. Silencing p62 could reverse the upregulation expression of Nrf2 and downregulation of Keap1 and Tau proteins induced by AP in aluminum maltolate-treated cells.

CONCLUSIONS

AP had neuroprotective effects against aluminum -induced cognitive dysfunction or cytotoxicity, which was involved in the activation of the p62-keap1-Nrf2 pathway and may develop as therapeutic drugs for the treatment of AD. However, this study has certain limitations, further optimize the protocol or model and study the molecular mechanism of AP improving AD.

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.

Intramuscularly Administered PLGA Microparticles for Sustained Release of Rivastigmine: In Vitro, In Vivo and Histological Evaluation

Rivastigmine is an acetylcholinesterase (AchE) and butyrylcholinesterase (BchE) inhibitor drug approved by the US Food and Drug Administration (FDA) for the treatment of mild to moderate dementia of Alzheimer's type. However, its first-pass metabolism and gastrointestinal side effects negatively affect the tolerability and efficacy of oral therapy. These adverse effects could be avoided with the use of a sustained -release formulation as an intramuscular (IM) administration system. The objective of this work was to develop polylactic co-glycolic acid (PLGA) microparticles for the sustained release of rivastigmine and to evaluate its stability during storage, tissue tolerance, in vitro release, and in vivo pharmacokinetics after its IM administration. The microparticles were made by the solvent evaporation emulsion method. A series of formulation parameters (the type of polymer used, the amount of polymer used, the initial amount of rivastigmine, and the volume of PVA 0.1% w/v) were studied to achieve an encapsulation efficiency (EE) and a rivastigmine load of 54.8 ± 0.9% and 3.3 ± 0.1%, respectively. The microparticles, whose size was 56.1 ± 2.8 μm, had a spherical shape and a smooth surface. FT-IR analysis showed that there is no chemical interaction between rivastigmine and the polymer. PLGA microparticles maintain rivastigmine retained and stable under normal (5 ± 3 °C) and accelerated storage (25 ± 2 °C and 60 ± 5 % RH) conditions for at least 6 months. The microparticles behaved as a sustained release system both in vitro and in vivo compared to non-encapsulated rivastigmine. The IM administration of the formulation in rats did not produce significant tissue damage. However, it is necessary to reproduce the experiments with multiple doses to rule out a negative effect in terms of tolerability in chronic treatment. To the best of our knowledge, this study is the only one that has obtained the sustained release of rivastigmine from PLGA microparticles after IM administration in an in vivo model.

Discovery of novel benzofuran-based derivatives as acetylcholinesterase inhibitors for the treatment of Alzheimer's disease: Design, synthesis, biological evaluation, molecular docking and 3D-QSAR investigation

A series of novel benzofuran-based compounds 7a-s were designed, synthesized, and investigated in vitro as acetylcholinesterase inhibitors (AChEIs). Compounds 7c and 7e displayed promising inhibitory activity with IC50 values of 0.058 and 0.086 μM in comparison to donepezil with an IC50 value of 0.049 μM. The new molecules' antioxidant evaluation revealed that 7c, 7e, 7j, 7n, and 7q produced the strongest DPPH scavenging activity when compared to vitamin C. As it was the most promising AChEI, compound 7c was selected for further biological evaluation. Acute and chronic toxicity studies exhibited that 7c showed no signs of toxicity or adverse events, no significant differences in the blood profile, and an insignificant difference in hepatic enzymes, glucose, urea, creatinine, and albumin levels in the experimental rat group. Furthermore, 7c did not produce histopathological damage to normal liver, kidney, heart, and brain tissues, ameliorated tissue malonaldehyde (MDA) and glutathione (GSH) levels and reduced the expression levels of the APP and Tau genes in AD rats. Molecular docking results of compounds 7c and 7e showed good binding modes in the active site of the acetylcholinesterase enzyme, which are similar to the native ligand donepezil. 3D-QSAR analysis revealed the importance of the alkyl group in positions 2 and 3 of the phenyl moiety for the activity. Overall, these findings suggested that compound 7c could be deemed a promising candidate for the management of Alzheimer's disease.

Improper Application of a Rivastigmine Patch to the Back of the Neck Induced Toxic Symptoms

Rivastigmine is a highly effective drug for treating Alzheimer's disease. However, its addiction can be fatal, so proper use of this transdermal drug is needed. We herein report an 85-year-old woman with Alzheimer's disease who inappropriately placed rivastigmine patches on the back of her neck. She suffered from acute cholinergic syndrome, hypersalivation, anorexia, dyspnea, and vomiting. These symptoms disappeared when the improper use of rivastigmine patches was ceased. This case serves as a warning to physicians and pharmacists of the risk associated with the improper placement of rivastigmine patches.

Guidelines for pharmacotherapy in Alzheimer's disease - A primer on FDA-approved drugs

The growing prevalence of dementia makes it important for us to better understand its pathophysiology and treatment modalities, to improve the quality of life of patients and caregivers. Alzheimer's disease (AD), a neurodegenerative disease, is the most common form of amnestic dementia in the geriatric population. Pathophysiology of AD is widely attributed to aggregation of amyloid-beta (Aβ) plaques and hyperphosphorylation of tau proteins. Initial treatment modalities aimed to increase brain perfusion in a non-specific manner. Subsequent therapy focused on rectifying neurotransmitter imbalance in the brain. Newer drugs modify the progression of the disease by acting against aggregated Aβ plaques. However, not all drugs used in therapy of AD have been granted approval by the United States Food and Drug Administration (FDA). This review categorizes and summarizes the FDA-approved drugs in the treatment of AD in a manner that would make it a convenient reference for researchers and practicing physicians alike. Drugs that mitigate symptoms of dementia may be categorized into mitigators of Behavioral and Psychological Symptoms of Dementia (BPSD), and mitigators of cognitive decline. BPSD mitigators include brexpiprazole, an atypical antipsychotic with a once-daily dosage suited to treat agitation in dementia patients, and suvorexant, an orexin receptor antagonist used to treat sleep disturbances. Cognitive decline mitigators include cholinesterase inhibitors such as donepezil, rivastigmine, and galantamine and glutamate inhibitors such as memantine. Donepezil is the most commonly prescribed drug. It is cheap, well-tolerated, and may be prescribed orally once daily, or as a transdermal patch once weekly. It increases ACh levels, enhances oligodendrocyte differentiation and also protects against Aβ toxicity. However, regular cardiac monitoring is required due to reports of cardiac conduction side effects. Rivastigmine requires a twice-daily oral dosage or once-daily replacement of transdermal patch. It has fewer cardiac side effects than donepezil, but local application-site reactions have been noted. Galantamine, in addition to improving cognitive symptoms in a short span of time, also delays the development of BPSDs and has minimal drug-drug interactions by virtue of having multiple metabolic pathways. However, cardiac conduction disturbances must be closely monitored for. Memantine, a glutamate regulator, acts as an anti-Parkinsonian agent and an antidepressant, in addition to improving cognition and neuroprotection, and requires a once-daily dosage in the form of immediate-release or sustained-release oral tablets. Disease-modifying drugs such as aducanumab and lecanemab reduce the Aβ burden. Both act by binding with fibrillary conformations of Aβ plaques in the brain. These drugs have a risk of causing amyloid-related imaging abnormalities, especially in persons with ApoE4 gene. Aducanumab is administered once every 4 weeks and lecanemab once every 2 weeks. The decision on the choice of the drug must be made after considering the availability of drug, compliance of patient (once-daily vs. multiple doses daily), cost, specific comorbidities, and the risk-benefit ratio for the particular patient. Other non-pharmacological treatment modalities must also be adopted to have a holistic approach toward the treatment of AD.

Alzheimer's disease: Molecular aspects and treatment opportunities using herbal drugs

Alzheimer's disease (AD), also called senile dementia, is the most common neurological disorder. Around 50 million people, mostly of advanced age, are suffering from dementia worldwide and this is expected to reach 100-130 million between 2040 and 2050. AD is characterized by impaired glutamatergic and cholinergic neurotransmission, which is associated with clinical and pathological symptoms. AD is characterized clinically by loss of cognition and memory impairment and pathologically by senile plaques formed by Amyloid β deposits or neurofibrillary tangles (NFT) consisting of aggregated tau proteins. Amyloid β deposits are responsible for glutamatergic dysfunction that develops NMDA dependent Ca2+ influx into postsynaptic neurons generating slow excitotoxicity process leading to oxidative stress and finally impaired cognition and neuronal loss. Amyloid decreases acetylcholine release, synthesis and neuronal transport. The decreased levels of neurotransmitter acetylcholine, neuronal loss, tau aggregation, amyloid β plaques, increased oxidative stress, neuroinflammation, bio-metal dyshomeostasis, autophagy, cell cycle dysregulation, mitochondrial dysfunction, and endoplasmic reticulum dysfunction are the factors responsible for the pathogenesis of AD. Acetylcholinesterase, NMDA, Glutamate, BACE1, 5HT6, and RAGE (Receptors for Advanced Glycation End products) are receptors targeted in treatment of AD. The FDA approved acetylcholinesterase inhibitors Donepezil, Galantamine and Rivastigmine and N-methyl-D-aspartate antagonist Memantine provide symptomatic relief. Different therapies such as amyloid β therapies, tau-based therapies, neurotransmitter-based therapies, autophagy-based therapies, multi-target therapeutic strategies, and gene therapy modify the natural course of the disease. Herbal and food intake is also important as preventive strategy and recently focus has also been placed on herbal drugs for treatment. This review focuses on the molecular aspects, pathogenesis and recent studies that signifies the potential of medicinal plants and their extracts or chemical constituents for the treatment of degenerative symptoms related to AD.

Advances in the treatment and management of frontotemporal dementia

INTRODUCTION

Frontotemporal dementia (FTD) is a complex neurodegenerative disorder, characterized by a wide range of pathological conditions associated with the buildup of proteins such as tau and TDP-43. With a strong hereditary component, FTD often results from genetic variants in three genes - MAPT, GRN, and C9orf72.

AREAS COVERED

In this review, the authors explore abnormal protein accumulation in FTD and forthcoming treatments, providing a detailed analysis of new diagnostic advancements, including innovative markers. They analyze how these discoveries have influenced therapeutic strategies, particularly disease-modifying treatments, which could potentially transform FTD management. This comprehensive exploration of FTD from its molecular underpinnings to its therapeutic prospects offers a compelling overview of the current state of FTD research.

EXPERT OPINION

Notable challenges in FTD management involve identifying reliable biomarkers for early diagnosis and response monitoring. Genetic forms of FTD, particularly those linked to C9orf72 and GRN, show promise, with targeted therapies resulting in substantial progress in disease-modifying strategies. The potential of neuromodulation techniques, like tDCS and rTMS, is being explored, requiring further study. Ongoing trials and multi-disciplinary care highlight the continued push toward effective FTD treatments. With increasing understanding of FTD's molecular and clinical intricacies, the hope for developing effective interventions grows.

Advances of computer-aided drug design (CADD) in the development of anti-Azheimer's-disease drugs

Alzheimer's disease (AD) is a degenerative disease of the nervous system that progressively destroys memory and thinking skills. Currently there is no treatment to prevent or cure AD; targeting the direct cause of neuronal degeneration would constitute a rational strategy and hopefully offer better options for the treatment of AD. This paper first summarizes the physiological and pathological pathogenesis of AD and then discusses the representative drug candidates for targeted therapy of AD and their binding mode with their targets. Finally, the applications of computer-aided drug design in discovering anti-AD drugs are reviewed. Teaser.

Targeting Sigma Receptors for the Treatment of Neurodegenerative and Neurodevelopmental Disorders

The sigma-1 receptor is a 223 amino acid-long protein with a recently identified structure. The sigma-2 receptor is a genetically unrelated protein with a similarly shaped binding pocket and acts to influence cellular activities similar to the sigma-1 receptor. Both proteins are highly expressed in neuronal tissues. As such, they have become targets for treating neurological diseases, including Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), multiple sclerosis (MS), Rett syndrome (RS), developmental and epileptic encephalopathies (DEE), and motor neuron disease/amyotrophic lateral sclerosis (MND/ALS). In recent years, there have been many pre-clinical and clinical studies of sigma receptor (1 and 2) ligands for treating neurological disease. Drugs such as blarcamesine, dextromethorphan and pridopidine, which have sigma-1 receptor activity as part of their pharmacological profile, are effective in treating multiple aspects of several neurological diseases. Furthermore, several sigma-2 receptor ligands are under investigation, including CT1812, rivastigmine and SAS0132. This review aims to provide a current and up-to-date analysis of the current clinical and pre-clinical data of drugs with sigma receptor activities for treating neurological disease.

Phytochemicals: A Promising Alternative for the Prevention of Alzheimer's Disease

Alzheimer's disease (AD) is a neurological condition that worsens with ageing and affects memory and cognitive function. Presently more than 55 million individuals are affected by AD all over the world, and it is a leading cause of death in old age. The main purpose of this paper is to review the phytochemical constituents of different plants that are used for the treatment of AD. A thorough and organized review of the existing literature was conducted, and the data under the different sections were found using a computerized bibliographic search through the use of databases such as PubMed, Web of Science, Google Scholar, Scopus, CAB Abstracts, MEDLINE, EMBASE, INMEDPLAN, NATTS, and numerous other websites. Around 360 papers were screened, and, out of that, 258 papers were selected on the basis of keywords and relevant information that needed to be included in this review. A total of 55 plants belonging to different families have been reported to possess different bioactive compounds (galantamine, curcumin, silymarin, and many more) that play a significant role in the treatment of AD. These plants possess anti-inflammatory, antioxidant, anticholinesterase, and anti-amyloid properties and are safe for consumption. This paper focuses on the taxonomic details of the plants, the mode of action of their phytochemicals, their safety, future prospects, limitations, and sustainability criteria for the effective treatment of AD.

Photobiomodulation in Alzheimer's Disease-A Complementary Method to State-of-the-Art Pharmaceutical Formulations and Nanomedicine?

Alzheimer's disease (AD), as a neurodegenerative disorder, usually develops slowly but gradually worsens. It accounts for approximately 70% of dementia cases worldwide, and is recognized by WHO as a public health priority. Being a multifactorial disease, the origins of AD are not satisfactorily understood. Despite huge medical expenditures and attempts to discover new pharmaceuticals or nanomedicines in recent years, there is no cure for AD and not many successful treatments are available. The current review supports introspection on the latest scientific results from the specialized literature regarding the molecular and cellular mechanisms of brain photobiomodulation, as a complementary method with implications in AD. State-of-the-art pharmaceutical formulations, development of new nanoscale materials, bionanoformulations in current applications and perspectives in AD are highlighted. Another goal of this review was to discover and to speed transition to completely new paradigms for the multi-target management of AD, to facilitate brain remodeling through new therapeutic models and high-tech medical applications with light or lasers in the integrative nanomedicine of the future. In conclusion, new insights from this interdisciplinary approach, including the latest results from photobiomodulation (PBM) applied in human clinical trials, combined with the latest nanoscale drug delivery systems to easily overcome protective brain barriers, could open new avenues to rejuvenate our central nervous system, the most fascinating and complex organ. Picosecond transcranial laser stimulation could be successfully used to cross the blood-brain barrier together with the latest nanotechnologies, nanomedicines and drug delivery systems in AD therapy. Original, smart and targeted multifunctional solutions and new nanodrugs may soon be developed to treat AD.

The Amyloid Cascade Hypothesis in Alzheimer’s Disease: Should We Change Our Thinking?

Old age increases the risk of Alzheimer’s disease (AD), the most common neurodegenerative disease, a devastating disorder of the human mind and the leading cause of dementia. Worldwide, 50 million people have the disease, and it is estimated that there will be 150 million by 2050. Today, healthcare for AD patients consumes 1% of the global economy. According to the amyloid cascade hypothesis, AD begins in the brain by accumulating and aggregating Aβ peptides and forming β-amyloid fibrils (Aβ42). However, in clinical trials, reducing Aβ peptide production and amyloid formation in the brain did not slow cognitive decline or improve daily life in AD patients. Prevention studies in cognitively unimpaired people at high risk or genetically destined to develop AD also have not slowed cognitive decline. These observations argue against the amyloid hypothesis of AD etiology, its development, and disease mechanisms. Here, we look at other avenues in the research of AD, such as the presenilin hypothesis, synaptic glutamate signaling, and the role of astrocytes and the glutamate transporter EAAT2 in the development of AD.

Treatment of Vascular and Neurodegenerative Forms of Cognitive Impairment and Dementias

Ideally, dementia care should be provided by a collaborative team. Eligible patients should be treated with the cognitive-enhancing medications, the cholinesterase inhibitors and memantine. For most of the common causes of dementia, there are no disease-modifying medications, with the exception that vascular dementia can be prevented by treating vascular risk factors to prevent stroke. There is hope that Alzheimer disease can be treated by using monoclonal antibodies that target amyloid beta, although more trials are needed. Holistic, patient-centered care can enhance quality and extend the time that the patient can live safely in the community.

Recent Advances in Intranasal Liposomes for Drug, Gene, and Vaccine Delivery

Liposomes are safe, biocompatible, and biodegradable spherical nanosized vesicles produced from cholesterol and phospholipids. Recently, liposomes have been widely administered intranasally for systemic and brain delivery. From the nasal cavity, liposome-encapsulated drugs and genes enter the systemic circulation primarily via absorption in the respiratory region, whereas they can be directly transported to the brain via the olfactory pathway. Liposomes can protect drugs and genes from enzymatic degradation, increase drug absorption across the nasal epithelium, and prolong the residence time in the nasal cavity. Intranasal liposomes are also a potential approach for vaccine delivery. Liposomes can be used as a platform to load antigens and as vaccine adjuvants to induce a robust immune response. With the recent interest in intranasal liposome formulations, this review discusses various aspects of liposomes that make them suitable for intranasal administration. We have summarized the latest advancements and applications of liposomes and evaluated their performance in the systemic and brain delivery of drugs and genes administered intranasally. We have also reviewed recent advances in intranasal liposome vaccine development and proposed perspectives on the future of intranasal liposomes.

Application of Marine Natural Products against Alzheimer's Disease: Past, Present and Future

Alzheimer's disease (AD), a neurodegenerative disease, is one of the most intractable illnesses which affects the elderly. Clinically manifested as various impairments in memory, language, cognition, visuospatial skills, executive function, etc., the symptoms gradually aggravated over time. The drugs currently used clinically can slow down the deterioration of AD and relieve symptoms but cannot completely cure them. The drugs are mainly acetylcholinesterase inhibitors (AChEI) and non-competitive N-methyl-D-aspartate receptor (NDMAR) antagonists. The pathogenesis of AD is inconclusive, but it is often associated with the expression of beta-amyloid. Abnormal deposition of amyloid and hyperphosphorylation of tau protein in the brain have been key targets for past, current, and future drug development for the disease. At present, researchers are paying more and more attention to excavate natural compounds which can be effective against Alzheimer's disease and other neurodegenerative pathologies. Marine natural products have been demonstrated to be the most prospective candidates of these compounds, and some have presented significant neuroprotection functions. Consequently, we intend to describe the potential effect of bioactive compounds derived from marine organisms, including polysaccharides, carotenoids, polyphenols, sterols and alkaloids as drug candidates, to further discover novel and efficacious drug compounds which are effective against AD.

Pathogenesis, Animal Models, and Drug Discovery of Alzheimer's Disease

Alzheimer's disease (AD), the most common cause of dementia, is a chronic neurodegenerative disease induced by multiple factors. The high incidence and the aging of the global population make it a growing global health concern with huge implications for individuals and society. The clinical manifestations are progressive cognitive dysfunction and lack of behavioral ability, which not only seriously affect the health and quality of life of the elderly, but also bring a heavy burden to the family and society. Unfortunately, almost all the drugs targeting the classical pathogenesis have not achieved satisfactory clinical effects in the past two decades. Therefore, the present review provides more novel ideas on the complex pathophysiological mechanisms of AD, including classical pathogenesis and a variety of possible pathogenesis that have been proposed in recent years. It will be helpful to find out the key target and the effect pathway of potential drugs and mechanisms for the prevention and treatment of AD. In addition, the common animal models in AD research are outlined and we examine their prospect for the future. Finally, Phase I, II, III, and IV randomized clinical trials or on the market of drugs for AD treatment were searched in online databases (Drug Bank Online 5.0, the U.S. National Library of Medicine, and Alzforum). Therefore, this review may also provide useful information in the research and development of new AD-based drugs.

miRNAs and Stem Cells as Promising Diagnostic and Therapeutic Targets for Alzheimer's Disease

Alzheimer's disease (AD) is a cumulative progressive neurodegenerative disease characterized mainly by impairment in cognitive functions accompanied by memory loss, disturbance in behavior and personality, and difficulties in learning. Although the main causes of AD pathogenesis are not fully understood yet, amyloid-β peptides and tau proteins are supposed to be responsible for AD onset and pathogenesis. Various demographic, genetic, and environmental risk factors are involved in AD onset and pathogenesis such as age, gender, several genes, lipids, malnutrition, and poor diet. Significant changes were observed in microRNA (miRNA) levels between normal and AD cases giving hope for a diagnostic procedure for AD through a simple blood test. As yet, only two classes of AD therapeutic drugs are approved by FDA. They are classified as acetylcholinesterase inhibitors and N-methyl-D-aspartate antagonists (NMDA). Unfortunately, they can only treat the symptoms but cannot cure AD or stop its progression. New therapeutic approaches were developed for AD treatment including acitretin due to its ability to cross blood-brain barrier in the brain of rats and mice and induce the expression of ADAM 10 gene, the α-secretase of human amyloid-β protein precursor, stimulating the non-amyloidogenic pathway for amyloid-β protein precursor processing resulting in amyloid-β reduction. Also stem cells may have a crucial role in AD treatment as they can improve cognitive functions and memory in AD rats through regeneration of damaged neurons. This review spotlights on promising diagnostic techniques such as miRNAs and therapeutic approaches such as acitretin and/or stem cells keeping in consideration AD pathogenesis, stages, symptoms, and risk factors.

Phytochemical Compounds and Nanoparticles as Phytochemical Delivery Systems for Alzheimer's Disease Management

Alzheimer's disease remains one of the most widespread neurodegenerative reasons for dementia worldwide and is associated with considerable mortality and morbidity. Therefore, it has been considered a priority for research. Indeed, several risk factors are involved in the complexity of the therapeutic ways of this pathology, including age, traumatic brain injury, genetics, exposure to aluminum, infections, diabetes, vascular diseases, hypertension, dyslipidemia, and obesity. The pathophysiology of Alzheimer's disease is mostly associated with hyperphosphorylated protein in the neuronal cytoplasm and extracellular plaques of the insoluble β-amyloid peptide. Therefore, the management of this pathology needs the screening of drugs targeting different pathological levels, such as acetylcholinesterase (AchE), amyloid β formation, and lipoxygenase inhibitors. Among the pharmacological strategies used for the management of Alzheimer's disease, natural drugs are considered a promising therapeutic strategy. Indeed, bioactive compounds isolated from different natural sources exhibit important anti-Alzheimer effects by their effectiveness in promoting neuroplasticity and protecting against neurodegeneration as well as neuroinflammation and oxidative stress in the brain. These effects involve different sub-cellular, cellular, and/or molecular mechanisms, such as the inhibition of acetylcholinesterase (AchE), the modulation of signaling pathways, and the inhibition of oxidative stress. Moreover, some nanoparticles were recently used as phytochemical delivery systems to improve the effects of phytochemical compounds against Alzheimer's disease. Therefore, the present work aims to provide a comprehensive overview of the key advances concerning nano-drug delivery applications of phytochemicals for Alzheimer's disease management.

Current Pharmacotherapy and Multi-Target Approaches for Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by decreased synaptic transmission and cerebral atrophy with appearance of amyloid plaques and neurofibrillary tangles. Cognitive, functional, and behavioral alterations are commonly associated with the disease. Different pathophysiological pathways of AD have been proposed, some of which interact and influence one another. Current treatment for AD mainly involves the use of therapeutic agents to alleviate the symptoms in AD patients. The conventional single-target treatment approaches do not often cause the desired effect in the disease due to its multifactorial origin. Thus, multi-target strategies have since been undertaken, which aim to simultaneously target multiple targets involved in the development of AD. In this review, we provide an overview of the pathogenesis of AD and the current drug therapies for the disease. Additionally, rationales of the multi-target approaches and examples of multi-target drugs with pharmacological actions against AD are also discussed.

Current Update on Transcellular Brain Drug Delivery

It is well known that the presence of a blood-brain barrier (BBB) makes drug delivery to the brain more challenging. There are various mechanistic routes through which therapeutic molecules travel and deliver the drug across the BBB. Among all the routes, the transcellular route is widely explored to deliver therapeutics. Advances in nanotechnology have encouraged scientists to develop novel formulations for brain drug delivery. In this article, we have broadly discussed the BBB as a limitation for brain drug delivery and ways to solve it using novel techniques such as nanomedicine, nose-to-brain drug delivery, and peptide as a drug delivery carrier. In addition, the article will help to understand the different factors governing the permeability of the BBB, as well as various formulation-related factors and the body clearance of the drug delivered into the brain.

Linking the Amyloid, Tau, and Mitochondrial Hypotheses of Alzheimer's Disease and Identifying Promising Drug Targets

Damage or loss of brain cells and impaired neurochemistry, neurogenesis, and synaptic and nonsynaptic plasticity of the brain lead to dementia in neurodegenerative diseases, such as Alzheimer's disease (AD). Injury to synapses and neurons and accumulation of extracellular amyloid plaques and intracellular neurofibrillary tangles are considered the main morphological and neuropathological features of AD. Age, genetic and epigenetic factors, environmental stressors, and lifestyle contribute to the risk of AD onset and progression. These risk factors are associated with structural and functional changes in the brain, leading to cognitive decline. Biomarkers of AD reflect or cause specific changes in brain function, especially changes in pathways associated with neurotransmission, neuroinflammation, bioenergetics, apoptosis, and oxidative and nitrosative stress. Even in the initial stages, AD is associated with Aβ neurotoxicity, mitochondrial dysfunction, and tau neurotoxicity. The integrative amyloid-tau-mitochondrial hypothesis assumes that the primary cause of AD is the neurotoxicity of Aβ oligomers and tau oligomers, mitochondrial dysfunction, and their mutual synergy. For the development of new efficient AD drugs, targeting the elimination of neurotoxicity, mutual potentiation of effects, and unwanted protein interactions of risk factors and biomarkers (mainly Aβ oligomers, tau oligomers, and mitochondrial dysfunction) in the early stage of the disease seems promising.

Pivotal role of nitrogen heterocycles in Alzheimer's disease drug discovery

Alzheimer's disease (AD) is a detrimental neurodegenerative disease that progressively worsens with time. Clinical options are limited and only provide symptomatic relief to AD patients. The search for effective anti-AD compounds is ongoing with a few already in Phase III clinical trials, yet to be approved. Heterocycles containing nitrogen are important to biological processes owing to their abundance in nature, their function as subunits of biological molecules and/or macromolecular structures, and their biological activities. The present review discusses previously used strategies, SAR, relevant in vitro and in vivo studies, and success stories of nitrogen-containing heterocyclic compounds in AD drug discovery. Also, we propose strategies for designing and developing novel potent anti-AD small molecules that can be used as treatments for AD.

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.

Micro- and Nanosized Carriers for Nose-to-Brain Drug Delivery in Neurodegenerative Disorders

Neurodegenerative disorders (NDs) have become a serious health problem worldwide due to the rapid increase in the number of people that are affected and the constantly aging population. Among all NDs, Alzheimer’s and Parkinson’s disease are the most common, and many efforts have been made in the development of effective and reliable therapeutic strategies. The intranasal route of drug administration offers numerous advantages, such as bypassing the blood–brain barrier and providing a direct entrance to the brain through the olfactory and trigeminal neurons. The present review summarizes the available information on recent advances in micro- and nanoscale nose-to-brain drug-delivery systems as a novel strategy for the treatment of Alzheimer’s and Parkinson’s disease. Specifically, polymer- and lipid-base micro- and nanoparticles have been studied as a feasible approach to increase the brain bioavailability of certain drugs. Furthermore, nanocomposites are discussed as a suitable formulation for administration into the nasal cavity.

Bioavailability Study of a Transdermal Patch Formulation of Rivastigmine Compared with Exelon in Healthy Subjects

BACKGROUND AND OBJECTIVES

Rivastigmine is a reversible cholinesterase inhibitor indicated for the treatment of all stages of Alzheimer's disease (AD). Transdermal patch formulation allows smooth and continuous drug delivery. Its tolerability, efficacy and convenience of use increase treatment compliance. This study was designed to evaluate the bioavailability and to assess the bioequivalence of two rivastigmine transdermal patches at steady state (RIV-TDS Test Product versus Exelon Marketed Reference Product), with a release rate of 13.3 mg/24 h, after multiple patch applications. As secondary objectives, safety, patch adhesion and skin irritation were evaluated.

METHODS

This was an open-label, randomized, balanced, two-period, two-sequence, cross-over study of healthy adults (n = 31). The treatment period consisted of two 5-day study periods during which consecutive daily application of the investigational patches with a release rate of 13.3 mg/24 h rivastigmine took place. Serial blood samples were collected to measure plasma concentrations. Adhesion and skin irritation assessments were performed after application of patches.

RESULTS

Point estimates and 90% confidence intervals of pharmacokinetic parameters at steady state, viz. area under the plasma concentration versus time curve from dosing time to the end of the dosing interval τ (profile day) at steady state [AUC_0-τ,ss] (97.4; 88.8-106.9), maximum plasma concentration within the dosing interval τ (profile day) at steady state [C_max,ss] (99.6; 90.4-109.7) and trough plasma concentration at the end of the dosing interval τ (profile day) at steady state [C_τ,ss] (96.8; 86.2-108.9), demonstrated that both patches were bioequivalent. Evaluation of patch adhesion showed better skin adherence for RIV-TDS as well as dermal response scores (skin tolerability after removal).

CONCLUSIONS

For both products, bioequivalence was shown and systemic tolerability was in accordance with the safety profile of the drug substance. The trial is registered in ClinicalTrials.gov: NCT03573050 and EudraCT: 2018-000968-28.

Comparative Bioavailability Study of a Novel Multi-Day Patch Formulation of Rivastigmine (Twice Weekly) with Exelon® Transdermal Patch (Daily)- A Randomized Clinical Trial

BACKGROUND

Rivastigmine, a reversible AChEI for symptomatic treatment of mild to moderately severe Alzheimer's dementia, is administered once daily transdermal patches, enabling an easier and continuous drug delivery. A novel multi-day (twice week) patch formulation was developed with greater convenience for patients' therapeutic management.

OBJECTIVE

To assess the bioequivalence under SS conditions of the multiple-day rivastigmine transdermal patch (Test Product, RID-TDS) in comparison to the once-daily Exelon® transdermal patch (Reference Product), both at a release rate of 9.5 mg/24 h.

DESIGN

Single-center, open-label, randomized, multiple-dose study in healthy male adults in a 2- period, 2-sequence-crossover design with multiple applications.

METHODS

Patches were applied on 11 consecutive days for Exelon® and a 4-3-4-day regimen for the multiday test patch (RID-TDS), separated by a 14-day wash-out period. The safety, local tolerability and inhibitory effect of rivastigmine on plasma BuChE activity were also evaluated.

RESULTS

57 subjects completed the study according to the protocol. Calculated point estimates and 90% CI for all primary parameters (AUC_96-264, Cmax_96-264 and Cmin_96-264) were within the predefined acceptance interval of 80.00-125.00%. They were 113.64% (107.33-120.33), 105.14% (98.38- 112.38) and 107.82% (97.78-118.89) respectively. Satisfactory adhesion (CI of mean adhesion above 90%) was demonstrated for RID-TDS but not for Exelon®.

CONCLUSION

Bioequivalence was demonstrated between RID-TDS mg twice a week and Exelon® once daily in SS. Patch adhesion favored RID-TDS despite the longer dosing interval. Both products were well tolerated.

In silico analyses of acetylcholinesterase (AChE) and its genetic variants in interaction with the anti-Alzheimer drug Rivastigmine

Alzheimer's disease (AD) is the leading cause of dementia worldwide. Despite causing great social and economic impact, there is currently no cure for AD. The most effective therapy to manage AD symptoms is based on acetylcholinesterase inhibitors (AChEi), from which rivastigmine presented numerous benefits. However, mutations in AChE, which affect approximately 5% of the population, can modify protein structure and function, changing the individual response to Alzheimer's treatment. In this study, we performed computer simulations of AChE wild type and variants R34Q, P135A, V333E, and H353N, identified by one or more genome-wide association studies, to evaluate their effects on protein structure and interaction with rivastigmine. The functional effects of AChE variants were predicted using eight machine learning algorithms, while the evolutionary conservation of AChE residues was analyzed using the ConSurf server. Autodock4.2.6 was used to predict the binding modes for the hAChE-rivastigmine complex, which is still unknown. Molecular dynamics (MD) simulations were performed in triplicates for the AChE wild type and mutants using the GROMACS packages. Among the analyzed variants, P135A was classified as deleterious by all the functional prediction algorithms, in addition to occurring at highly conserved positions, which may have harmful consequences on protein function. The molecular docking results suggested that rivastigmine interacts with hAChE at the upper active-site gorge, which was further confirmed by MD simulations. Our MD findings also suggested that the complex hAChE-rivastigmine remains stable over time. The essential dynamics revealed flexibility alterations at the active-site gorge upon mutations P135A, V333E, and H353N, which may lead to strong and nonintuitive consequences to hAChE binding. Nonetheless, similar binding affinities were registered in the MMPBSA analysis for the hAChE wild type and variants when complexed to rivastigmine. Finally, our findings indicated that the rivastigmine binding to hAChE is an energetically favorable process mainly driven by negatively charged amino acids.

Beneath the Skin: A Review of Current Trends and Future Prospects of Transdermal Drug Delivery Systems

The ideal drug delivery system has a bioavailability comparable to parenteral dosage forms but is as convenient and easy to use for the patient as oral solid dosage forms. In recent years, there has been increased interest in transdermal drug delivery (TDD) as a non-invasive delivery approach that is generally regarded as being easy to administer to more vulnerable age groups, such as paediatric and geriatric patients, while avoiding certain bioavailability concerns that arise from oral drug delivery due to poor absorbability and metabolism concerns. However, despite its many merits, TDD remains restricted to a select few drugs. The physiology of the skin poses a barrier against the feasible delivery of many drugs, limiting its applicability to only those drugs that possess physicochemical properties allowing them to be successfully delivered transdermally. Several techniques have been developed to enhance the transdermal permeability of drugs. Both chemical (e.g., thermal and mechanical) and passive (vesicle, nanoparticle, nanoemulsion, solid dispersion, and nanocrystal) techniques have been investigated to enhance the permeability of drug substances across the skin. Furthermore, hybrid approaches combining chemical penetration enhancement technologies with physical technologies are being intensively researched to improve the skin permeation of drug substances. This review aims to summarize recent trends in TDD approaches and discuss the merits and drawbacks of the various chemical, physical, and hybrid approaches currently being investigated for improving drug permeability across the skin.

Hypoxic and Hypercapnic Responses in Transgenic Murine Model of Alzheimer’s Disease Overexpressing Human AβPP: The Effects of Pretreatment with Memantine and Rivastigmine

Despite the severe respiratory problems reducing the quality of life for Alzheimer’s disease (AD) patients, their causes are poorly understood. We aimed to investigate hypoxic and hypercapnic respiratory responses in a transgenic mouse model of AD (AβPP V717I) overexpressing AβPP and mimicking early-onset AD. The cholinesterase inhibitor rivastigmine and the NMDA receptor antagonist memantine were used to investigate the effects of drugs, used to treat AD cognitive dysfunction, on breathing in hypoxia and hypercapnia. We found a significant increase in the respiratory response to hypercapnia and no difference in the hypoxic response in APP+ mice, compared with the control group (APP−). Memantine had no effect on respiration in either group, including responses to hypoxia and hypercapnia. Rivastigmine depressed resting ventilation and response to hypercapnia irrespective of the mice genotype. Reduction in hypoxia-augmented ventilation by rivastigmine was observed only in APP+ mice, which exhibited lower acetylcholinesterase activity in the hippocampus. Treatment with rivastigmine reduced the enzyme activity in both groups equally in the hippocampus and brainstem. The increased ventilatory response to hypercapnia in transgenic mice may indicate alterations in chemoreceptive respiratory nuclei, resulting in increased CO₂ sensitivity. Rivastigmine is a potent reductant of normoxic and hypercapnic respiration in APP+ and APP− mice.

The listed, delisted, and sustainability of therapeutic medicines for dementia patients: the study is specific to South Korea

The Dementia Management Act (DMA) came into effect on August 4, 2011, in South Korea. Diagnosis and medication were rapidly performed for dementia in a short time. We investigated the cardiac effects of increased drug prescription following DMA. We observed a correlation between Alzheimer’s disease (AD) and anti-AD drug (AAD) groups from 2010 to 2019 on the National Health Insurance System (NHIS) of South Korea. This study investigated the increase and decrease in deaths of AD patients with AAD. We analysed the mortality per 100,000 population with the R² Calculator. Moreover, we made the up or down datum line for the simple decision on the listed, delisted, and sustainable drug examined by a linear equation and R². We observed that life expectancy was diminished by AAD in Sorokdo National Hospital. In the NHIS, donepezil and rivastigmine increased the number of deaths decided on R² > 0.75. Memantine was sustainable. We could not decide on galantamine because it is one of the other groups. We made a straightforward decision-maker of delisted, listed, or sustainable criteria based on mortality and datum line.

Risk of overactive bladder associated with cholinesterase inhibitors in dementia

BACKGROUND

Although cholinesterase inhibitors (ChEIs) are the primary treatment for dementia, they are associated with overactive bladder (OAB), necessitating antimuscarinic use. Limited data exist regarding the risk of OAB across individual ChEIs in dementia. This study evaluated the risk of OAB associated with individual ChEIs in older adults with dementia.

METHODS

This was a new user retrospective cohort study using Medicare claims data involving Parts A, B, and D claims dataset from 2013 to 2015. The study included older adults (aged 65 and older) with a diagnosis of dementia using donepezil, galantamine, or rivastigmine. New ChEI claims were identified with a 6-month baseline washout period. Patients with OAB diagnosis or any antimuscarinic or mirabegron use in the baseline period were excluded. The primary outcome of interest was OAB diagnosis or prescription of antimuscarinics or mirabegron within 6 months of ChEI initiation. Multivariable cox proportional hazards regression with propensity scores (PS) as covariates and inverse probability of treatment weighting generated using generalized boosted models was used to assess the risk of OAB among donepezil, galantamine, and rivastigmine users.

RESULTS

The study included 524,975 older adults with dementia who were incident users of ChEIs (donepezil 80.72%, rivastigmine 16.41%, galantamine 2.87%). Overall, OAB diagnosis/antimuscarinic/mirabegron prescription was observed in 5.07% of the cohort within 6 months of ChEIs prescription. The Cox regression model with PS as covariate approach found that donepezil use increased the risk of OAB compared to rivastigmine (aHR, 1.13; 95% CI, 1.08-1.28; p < 0.0001). However, there was no differential risk of OAB between galantamine and rivastigmine. The findings were consistent with the generalized boosted models.

CONCLUSIONS

The study found that the risk of OAB varies across individual ChEIs with an increased risk of OAB with donepezil compared to rivastigmine. The study findings suggest the need to understand and manage medication-related morbidity in older adults with dementia.

Optimized Rivastigmine Nanoparticles Coated with Eudragit for Intranasal Application to Brain Delivery: Evaluation and Nasal Ciliotoxicity Studies

Rivastigmine, a reversible cholinesterase inhibitor, is frequently indicated in the management of demented conditions associated with Alzheimer disease. The major hurdle of delivering this drug through the oral route is its poor bioavailability, which prompted the development of novel delivery approaches for improved efficacy. Due to numerous beneficial properties associated with nanocarriers in the drug delivery system, rivastigmine nanoparticles were fabricated to be administer through the intranasal route. During the development of the nanoparticles, preliminary optimization of processing and formulation parameters was done by the design of an experimental approach. The drug-polymer ratio, stirrer speed, and crosslinking time were fixed as independent variables, to analyze the effect on the entrapment efficiency (% EE) and in vitro drug release of the drug. The formulation (D8) obtained from 2³ full factorial designs was further coated using Eudragit EPO to extend the release pattern of the entrapped drug. Furthermore, the 1:1 ratio of core to polymer depicted spherical particle size of ~175 nm, % EE of 64.83%, 97.59% cumulative drug release, and higher flux (40.39 ± 3.52 µg.h/cm²). Finally, the intranasal ciliotoxicity study on sheep nasal mucosa revealed that the exposure of developed nanoparticles was similar to the negative control group, while destruction of normal architecture was noticed in the positive control test group. Overall, from the in vitro results it could be summarized that the optimization of nanoparticles' formulation of rivastigmine for intranasal application would be retained at the application site for a prolonged duration to release the entrapped drug without producing any local toxicity at the mucosal region.

Pharmacokinetic and pharmacodynamic evaluation of nasal liposome and nanoparticle based rivastigmine formulations in acute and chronic models of Alzheimer's disease

With the increasing aging population and progressive nature of the disease, Alzheimer's disease (AD) poses to be an oncoming epidemic with limited therapeutic strategies. It is characterized by memory loss, behavioral instability, impaired cognitive function, predominantly, cognitive inability manifested due to the accumulation of β-amyloid, with malfunctioned cholinergic system. Rivastigmine, a reversible dual cholinesterase inhibitor, is a more tolerable and widely used choice of drug for AD. However, rivastigmine being hydrophilic and undergoing the first-pass metabolism exhibits low CNS bioavailability. Nanoformulations including liposomes and PLGA nanoparticles can encapsulate hydrophilic drugs and deliver them efficiently to the brain. Besides, the nasal route is receiving considerable attention recently, due to its direct access to the brain. Therefore, the present study attempts to evaluate the pharmacokinetic and pharmacodynamic properties of nasal liposomal and PLGA nanoparticle formulations of rivastigmine in acute scopolamine-induced amnesia and chronic colchicine induced cognitive dysfunction animal models, and validate the best formulation by employing pharmacokinetic and pharmacodynamic (PK-PD) modeling. Nasal liposomal rivastigmine formulation showed the best pharmacokinetic features with rapid onset of action (Tmax = 5 min), higher Cmax (1489.5 ± 620.71), enhanced systemic bioavailability (F = 118.65 ± 23.54; AUC = 35,921.75 ± 9559.46), increased half-life (30.92 ± 8.38 min), and reduced clearance rate (Kel (1/min) = 0.0224 ± 0.006) compared to oral rivastigmine (Tmax = 15 min; Cmax = 56.29 ± 27.05; F = 4.39 ± 1.82; AUC = 1663.79 ± 813.54; t1/2 = 13.48 ± 5.79; Kel (1/min) = 0.0514 ± 0.023). Further, the liposomal formulation significantly rescued the memory deficit induced by scopolamine as well as colchicine superior to other formulations as assessed in Morris water maze and passive avoidance tasks. PK-PD modeling demonstrated a strong correlation between the pharmacokinetic parameters and acetylcholinesterase inhibition of liposomal formulation.

Real-world Utilisation of the Rivastigmine Transdermal Patches Accompanying the use of Risk Minimisation Tools in Patients with Dementia

BACKGROUND

Transdermal patches are convenient to use, especially in patients with Alzheimer's disease (AD)-associated dementia. However, various identified risks of errors in ad- ministering the patches cannot be disregarded. Patient Reminder Cards (PRCs, included a Medica- tion record sheet [MRS]) have been recently introduced as a risk minimisation tool to prevent incor- rect patch use (IU).

OBJECTIVES

This study aimed to assess the effectiveness of PRCs to prevent IU and to investigate the dose titration pattern of rivastigmine patches in a real-world setting.

METHODS

This multinational, observational, 11-month study included patients with AD currently using rivastigmine patches (4.6 mg/day, 9.5 mg/day, 13.3 mg/day) accompanied by a caregiver. Study outcomes were IU, including multiple patch use (MPU), incorrect patch placement, other IUs, perceived usefulness of the PRCs, and titration patterns of the patches.

RESULTS

Of the total 614 patients included, most were aged ≥65 years and had mild-to-moderate AD. Before and during the study, 27.7% and 18.0% of patients reported IU, respectively. Most pa- tients used MRS, and 73.5% rated it 'helpful' and reported lower rates of IU than those who report- ed it 'not helpful' (13.9%-16.5% vs. 20.2%). Overall, 141 patients had dose titrations, with 75.8% being up-titrated from 4.6 mg/day to 9.5 mg/day after a mean duration of 58 days. Safety findings were consistent with the established profile for the rivastigmine patch.

CONCLUSION

PRC was effective as a risk minimisation tool in limiting the inappropriate use of ri- vastigmine patches. The majority of patients requiring dose-change were up-titrated to 9.5 mg/day patches.

Effects of Noninvasive Brain Stimulation (NIBS) on Cognitive Impairment in Mild Cognitive Impairment and Alzheimer Disease: A Meta-analysis

OBJECTIVE

The purpose of this meta-analysis was to evaluate the beneficial effects and optimal stimulation protocol of noninvasive brain stimulation (NIBS) including repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) on patients with mild cognitive impairment and Alzheimer disease.

MATERIALS AND METHODS

PubMed, Web of Science, Embase, and the Cochrane Library were searched until March 2020. The cognitive outcomes were extracted and the standardized mean difference with 95% confidence interval was calculated.

RESULTS

Twenty-eight studies were included. The result of NIBS showed significant effect on global cognition (P<0.05). Low-frequency rTMS over right dorsolateral prefrontal cortex (DLPFC), high-frequency rTMS (HF-rTMS) over left DLPFC, and the tDCS over left DLPFC and temporal lobe can significantly improve the memory function (P<0.05). HF-rTMS over left, right, or bilateral DLPFC can significantly improve the language function (P<0.05). Both HF-rTMS and tDCS over left DLPFC can obviously improve the executive function (P<0.05). Multiple sessions of rTMS with 80% to 100% intensity and anode tDCS with 2 mA current density are more suitable for all these functions.

CONCLUSIONS

NIBS has a beneficial effect on cognitive performance in both mild cognitive impairment and Alzheimer disease patients. Distinct optimal stimulation parameters were observed for different cognitive functions.

An international, randomized, placebo-controlled, phase 2b clinical trial of intepirdine for dementia with Lewy bodies (HEADWAY-DLB)

INTRODUCTION

A phase 2b clinical trial, HEADWAY-DLB, was performed to assess treatment with intepirdine, a serotonin receptor antagonist, in patients with dementia with Lewy bodies (DLB).

METHODS

HEADWAY-DLB was a multinational, double-blind, randomized, placebo-controlled study. Two hundred sixty-nine DLB patients were randomized to receive placebo, 70 mg/day intepirdine, or 35 mg/day intepirdine over 24 weeks. The primary endpoint was change from baseline to week 24 on the Unified Parkinson's Disease Rating Scale-Part III (UPDRS-III).

RESULTS

Both intepirdine groups did not demonstrate significant benefits over placebo at 24 weeks on the UPDRS-III (35 mg/day: P = .1580, 70 mg/day: P = .6069). All other endpoints were not significant. Intepirdine was well tolerated, with a slightly higher incidence of gastrointestinal adverse events observed in the intepirdine groups versus placebo.

DISCUSSION

Intepirdine treatment did not lead to improvements over placebo in patients with DLB. As one of the largest DLB studies to date, HEADWAY-DLB demonstrates that international trials for DLB are feasible within a reasonable timeframe.

Binding interaction of protoberberine alkaloids against acetylcholinesterase (AChE) using molecular dynamics simulations and QM/MM calculations

Acetylcholinesterase (AChE) plays a vital role in Alzheimer's disease (AD), which is one of the most common causes of dementia. Discovering new effective inhibitors against AChE activity is seen to be one of the effective approaches to reduce the suffering from AD. Protoberberine alkaloids isolated from natural resources have previously been reported as potent AChE inhibitors. In order to gain insights into how these alkaloids could inhibit AChE, berberine, palmatine, and cyclanoline were selected to investigate in terms of binding orientation and their key interactions with AChE using molecular docking and molecular dynamics simulations and quantum chemical calculations. The results revealed that the molecular dynamics structures of palmatine and berberine indicated that their equilibrated structures did not occupy the gorge but they slightly moved away from the catalytic site (CAS). For cyclanoline, the binding mode was quite different from those of donepezil and the other protoberberine alkaloids: it preferred to stay deeper in the CAS site. Interaction energies and residual interaction energies confirmed that the key interactions for palmatine and berberine were π-π interactions with Trp286 and Tyr341 and H-bond interactions with Tyr124. Cyclanoline formed π-π interactions with Trp86 and H-bonds to the amino acids in the CAS site. The results suggested the importance of aromaticity in the core structure and the flexibility of the core structure or the substituents in order to fit into the narrow gorge. The HOMO, LUMO, bioavailability, drug-likeness and pharmacokinetics were also predicted. The results obtained will be useful for further AD drug development.