Safety and Efficacy of Donepezil 10 mg/day in Patients with Mild to Moderate Alzheimer’s Disease

Efficacy of 5 and 10 mg donepezil in improving cognitive function in patients with dementia: a systematic review and meta-analysis

Objective

The purpose of this study was to compare donepezil at 5 mg and 10 mg/day against a placebo to systematically evaluate its effectiveness in improving cognitive function among patients suffering from dementia at any stage.

Method

For this systematic review and meta-analysis, we looked up Medline, Scopus, Embase, Web of Science, and The Cochrane Library for articles on the efficacy of donepezil in dementia published in the past 20 years and summarized the placebo and intervention data. Initially, a total of 2,272 articles were extracted using our search query and after the inclusion and exclusion criteria set for extraction of data, 18 studies were included in this review using PRISMA flowchart. The ADAS-cog and MMSE assessment scales were used for measuring the outcomes using IBM SPSS 29.0 for the meta-analysis.

Result

The meta-analysis comprised a total of 18 RCTs (randomized controlled trials) that were randomized to receive either donepezil 5 mg/day (n = 1,556), 10 mg/day (n = 2050) or placebo (n = 2,342). Meta-analysis concerning efficacy showed that donepezil at 10 mg/day significantly improved the MMSE score (g: 2.27, 95%CI: 1.25-3.29) but could not substantially reduce the ADAS-cog. At 5 mg/day donepezil, an overall slight improvement in MMSE score (Hedges' g: 2.09, 95%CI: 0.88-3.30) was observed.

Conclusion

Both donepezil 5 mg/day and 10 mg/day doses demonstrated improved cognitive functions for patients with dementia, however results indicated that the 10 mg/day dose was more efficacious.

Alzheimer's disease phenotype based upon the carrier status of the apolipoprotein E ɛ4 allele

The apolipoprotein E ɛ4 allele (APOE4) is universally acknowledged as the most potent genetic risk factor for Alzheimer's disease (AD). APOE4 promotes the initiation and progression of AD. Although the underlying mechanisms are unclearly understood, differences in lipid-bound affinity among the three APOE isoforms may constitute the basis. The protein APOE4 isoform has a high affinity with triglycerides and cholesterol. A distinction in lipid metabolism extensively impacts neurons, microglia, and astrocytes. APOE4 carriers exhibit phenotypic differences from non-carriers in clinical examinations and respond differently to multiple treatments. Therefore, we hypothesized that phenotypic classification of AD patients according to the status of APOE4 carrier will help specify research and promote its use in diagnosing and treating AD. Recent reviews have mainly evaluated the differences between APOE4 allele carriers and non-carriers from gene to protein structures, clinical features, neuroimaging, pathology, the neural network, and the response to various treatments, and have provided the feasibility of phenotypic group classification based on APOE4 carrier status. This review will facilitate the application of APOE phenomics concept in clinical practice and promote further medical research on AD.

Effects of 3R, 16S-2-hydroxyethyl apovincaminate (HEAPO), donepezil and galantamine on learning and memory retention in naïve Wistar rats

The effects of 3R,16S-2-hydroxyethyl apovincaminate (HEAPO, RGH-10885) compared with those of two cholinesterase inhibitors, donepezil and galantamine, were examined in naïve Wistar rats using standard active and passive avoidance tests. The active avoidance test (shuttle box) and two passive avoidance tests (step-through and step-down) were performed according to the experimental design. There were 10 groups of rats (n = 8) and the substances studied were applied orally before each testing session. In the active avoidance test, the number of conditioned stimuli (avoidances), unconditioned stimuli (escapes) and intertrial crossings were observed. In step-down and step-through passive avoidance tests, the latencies of reactions were observed. All the studied compounds showed positive effects in the learning and memory tests, compared to the controls. It was concluded that HEAPO, donepezil and galantamine had a memory-enhancing effect in active and passive avoidance tests.

Neurotransmitters in Prevention and Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is the most frequent cause of cognitive impairment in middle-aged and older populations. There is a lack of drugs that demonstrate significant efficacy in AD, so the study of the pathogenesis of AD is of great importance. More efficacious interventions are needed, as reflected by our population's fast aging. Synaptic plasticity is the capacity of neurons to adjust their connections, and it is strongly tied to learning and memory, cognitive function, and brain injury recovery. Changes in synaptic strength, such as long-term potentiation (LTP) or inhibition (LTD), are thought to represent the biological foundation of the early stages of learning and memory. The results of numerous studies confirm that neurotransmitters and their receptors play an important role in the regulation of synaptic plasticity. However, so far, there is no definite correlation between the function of neurotransmitters in aberrant neural oscillation and AD-related cognitive impairment. We summarized the AD process to understand the impact of neurotransmitters in the progression and pathogenesis of AD, including the current status of neurotransmitter target drugs, and the latest evidence of neurotransmitters' function and changes in the AD process.

Thiazolidin-4-one prevents against memory deficits, increase in phosphorylated tau protein, oxidative damage and cholinergic dysfunction in Alzheimer disease model: Comparison with donepezil drug

Alzheimer's disease (AD) is characterized mostly by memory decline. The current therapeutic arsenal for treating AD is limited, and the available drugs only produce symptomatic benefits, but do not stop disease progression. The search for effective therapeutic alternatives with multitarget actions is therefore imperative. One such a potential alternative is thiazolidin-4-one, a compound that exhibits anti-amnesic, anticholinesterase, and antioxidant activities. The aim of this study was evaluated the effects of 2-(4-(methylthio)phenyl)- 3-(3-(piperidin-1-yl)propyl) thiazolidin-4-one (DS12) on memory and neurochemical parameters in a model of AD induced by an intracerebroventricular injection of streptozotocin (STZ). Adult male rats were divided into five groups: I, control (saline); II, DS12 (10 mg/kg); III, STZ; IV, STZ + DS12 (10 mg/kg); V, STZ + donepezil (5 mg/kg). The rats were orally treated with DS12 and donepezil for a period of 20 days. Memory, acetylcholinesterase (AChE) activity, phosphorylated tau protein levels and oxidative stress were analyzed in the cerebral cortex, hippocampus, and cerebellum. Biochemical and hematological parameters were evaluated in the blood and serum. Memory impairment and the increase in AChE activity and phosphorylated tau protein level induced by STZ were prevented by DS12 and donepezil treatment. Streptozotocin induces an increase in reactive oxygen species levels and a decrease in catalase activity in the hippocampus, cerebral cortex, and cerebellum. DS12 treatment conferred protection from oxidative alterations in all brain structures. No changes were observed in serum biochemical parameters (glucose, triglycerides, cholesterol, uric acid, and urea) or hematological parameters, such as platelets, lymphocytes, hemoglobin, hematocrit, and total plasma protein. DS12 improved memory and neurochemical changes in an AD model and did not show toxic effects, suggesting the promising therapeutic potential of this compound.

Current Drug Targets in Alzheimer's Associated Memory Impairment: A Comprehensive Review

Alzheimer's disease (AD) is the most prevalent form of dementia among geriatrics. It is a progressive, degenerative neurologic disorder that causes memory and cognition loss. The accumulation of amyloid fibrils and neurofibrillary tangles in the brain of AD patients is a distinguishing feature of the disease. Therefore, most of the current therapeutic goals are targeting inhibition of beta-amyloid synthesis and aggregation as well as tau phosphorylation and aggregation. There is also a loss of the cholinergic neurons in the basal forebrain, and first-generation therapeutic agents were primarily focused on compensating for this loss of neurons. However, cholinesterase inhibitors can only alleviate cognitive symptoms of AD and cannot reduce the progression of the disease. Understanding the molecular and cellular changes associated with AD pathology has advanced significantly in recent decades. The etiology of AD is complex, with a substantial portion of sporadic AD emerging from unknown reasons and a lesser proportion of early-onset familial AD (FAD) caused by a mutation in several genes, such as the amyloid precursor protein (APP), presenilin 1 (PS1), and presenilin 2 (PS2) genes. Hence, efforts are being made to discover novel strategies for these targets for AD therapy. A new generation of AChE and BChE inhibitors is currently being explored and evaluated in human clinical trials for AD symptomatic treatment. Other approaches for slowing the progression of AD include serotonergic modulation, H3 receptor antagonism, phosphodiesterase, COX-2, and MAO-B inhibition. The present review provides an insight into the possible therapeutic strategies and their molecular mechanisms, enlightening the perception of classical and future treatment approaches.

Recent advances in research on Alzheimer's disease in China

China has the largest number of individuals with dementia worldwide. Alzheimer's disease (AD) is a growing global health issue that seriously threatens human health and quality of life and imposes a significant burden on families and society. To date, no treatment exists that can delay AD progression. This review describes the current understanding of AD in China, including its prevalence, cost burden, diagnosis, and treatment, and summarizes the major advances in AD in China, including government strategies and research. Such findings highlight the need for a brain health action plan to prevent and control AD and to reduce its increasing prevalence and dementia-related costs in China.