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

Enhancement of neural regeneration as a therapeutic strategy for Alzheimer's disease (Review)

Alzheimer's disease (AD), the most common cause of dementia worldwide, has gradually become a global health concern for society and individuals with the process of global ageing. Although extensive research has been carried out on AD, the etiology and pathological mechanism of the disease are still unclear, and there is no specific drug to cure or delay AD progression. The exploration of enhancing nerve regeneration in AD has gradually attracted increasing attention. In the current review, the existing therapeutic strategies were summarized to induce nerve regeneration which can increase the number of neurons, and improve the survival of neurons, the plasticity of synapses and synaptic activity. The strategies include increasing neurotrophic expression (such as brain-derived neurotrophic factor and nerve growth factor), inhibiting acetylcholinesterase (such as donepezil, tacrine, rivastigmine and galanthamine), elevating histone deacetylase levels (such as RGFP-966, Tasquinimod, CM-414 and 44B), stimulating the brain by physiotherapy (such as near-infrared light, repetitive transcranial magnetic stimulation, and transcranial direct current stimulation) and transplanting exogenous neural stem cells. However, further evaluations need to be performed to determine the optimal treatment. The present study reviews recent interventions for enhancing adult neurogenesis and attempts to elucidate their mechanisms of action, which may provide a theoretical basis for inducing nerve regeneration to fight against AD.

Mapping new pharmacological interventions for cognitive function in Alzheimer's disease: a systematic review of randomized clinical trials

Background and Objective: Alzheimer's disease (AD) is a progressive neurodegenerative disorder, that is, characterized by cognitive decline. To date, there are no effective treatments for AD. Therefore, the objective of this study was to map new perspectives on the effects of pharmacological treatment on cognitive function and the overall psychological state in patients with AD. Methods: Two independent researchers searched for randomized clinical trials (RCTs) exploring new pharmacological approaches related to cognition in Alzheimer's disease in adults from 2018 to 2023 in PubMed, Web of Science, Scopus, and Cochrane Library databases. A total of 17 RCTs were included in this review. Results: The results show that in recent years, new drugs have been tested in patients with Alzheimer's disease, including masitinib, methylphenidate, levetiracetam, Jiannao Yizhi, and Huannao Yicong formulas. Most studies have been conducted in populations with mild to moderate Alzheimer's disease. Conclusion: Although some of the drugs found suggested improvement in cognitive function, the scarcity of available studies highlights the need for further research in this area. Systematic review registration: [www.crd.york.ac.uk/prospero], identifier [CRD42023409986].

Efficacy and safety of herbal medicine on dementia and cognitive function: An umbrella review of systematic reviews and meta-analysis

This study aims to summarize the effects of herbs on dementia and assess the strength of evidence. Six international and local databases were searched from inception to October 2021 for systematic reviews and meta-analyses of clinical trials investigated the effects of herbal medicine on dementia or cognitive function. Two researchers independently extracted data, assessed the methodological quality, and rated the credibility of evidence according to established criteria. Thirty-seven articles evaluating 13 herbal medicines were included. Of these, 65% were rated critically low using AMSTAR2. Of 90 unique outcomes, 41 (45.6%) were statistically significant based on random effects model (p ≤ .05). Only 3 herbs were supported by suggestive evidence whereas the others were supported by weak evidence. The suggestive evidence supported benefits of Chinese herbal medicine (CHM) plus pharmacotherapy (WMD:1.84; 95% CI: 1.34, 2.35) and Vinpocetine (WMD: -0.94; 95%CI: -1.50, -0.38) on improving cognitive function assessing by Montreal Cognitive Assessment and Syndrom-Kurz-Test, respectively. Moreover, suggestive evidence supported benefit of Huperzia serrata on improving Activities of Daily Living (WMD:-7.18; 95%CI: -9.12, -5.23). No SAE was reported. In conclusion, several herbs were used for improving dementia and cognitive function but recent evidence were limited by the small sample size and poor methodological quality. Therefore, further large and well-designed studies are needed to support the evidence.

Efficacy of pharmacotherapy and non-pharmacotherapy of Alzheimer dementia: A protocol for systematic review and meta-analysis

BACKGROUND

Alzheimer disease (AD) is the most common cause of dementia worldwide. Despite the publication of numerous systematic reviews and meta-analyses that have summarized the evidence associated with pharmacotherapies (PTs) and non-pharmacotherapies (NPTs) for the wide range of interventions available for AD treatment, their comparative safety and efficacy remains insufficiently defined.

METHODS

Systematic reviews of randomized controlled trials (RCTs) will be selected according to the following criteria: conducted in elderly patients aged 60 years or older with AD living in community or institutionalized settings, applied pairwise meta-analysis (PMA) or network meta-analysis (NMA) approaches providing pooled relative treatment effects for at least 1 pair of PTs or NPTs, and providing at least 1 of the following outcomes for patients/caregivers: cognitive, functional status, behavior, quality of life (QoL), and caregiver stress or burden. All article screening, data extraction, and risk of bias assessment will be completed independently by 2 reviewers. Relative treatment rankings will be reported with mean ranks and surface under the cumulative ranking curves.

RESULTS AND CONCLUSION

We will determine the most efficacious treatment strategies for AD patients from the most highly ranked treatments. These results will help to guide clinical decision-making and improve patient care.

A Synopsis of Multitarget Potential Therapeutic Effects of Huperzine A in Diverse Pathologies-Emphasis on Alzheimer's Disease Pathogenesis

Numerous challenges are confronted when it comes to the recognition of therapeutic agents for treating complex neurodegenerative diseases like Alzheimer's disease (AD). The perplexing pathogenicity of AD embodies cholinergic dysfunction, amyloid beta (Aβ) aggregation, neurofibrillary tangle formation, neuroinflammation, mitochondrial disruption along with vicious production of reactive oxygen species (ROS) generating oxidative stress. In this frame of reference, drugs with multi target components could prove more advantageous to counter complex pathological mechanisms that are responsible for AD progression. For as much as, medicinal plant based pharmaco-therapies are emerging as potential candidates for AD treatment keeping the efficacy and safety parameters in terms of toxicity and side effects into consideration. Huperzine A (Hup A) is a purified alkaloid compound extracted from a club moss called Huperzia serrata. Several studies have reported both cholinergic and non-cholinergic effects of this compound on AD with significant neuroprotective properties. The present review convenes cumulative demonstrations of neuroprotection provided by Hup A in in vitro, in vivo, and human studies in various pathologies. The underlying molecular mechanisms of its actions have also been discussed. However, more profound evidence would certainly promote the therapeutic implementation of this drug thus furnishing decisive insights into AD therapeutics and various other pathologies along with preventive and curative management.

Effects of New Galantamine Derivatives in a Scopolamine Model of Dementia in Mice

Alzheimer's disease (AD), a progressive neurodegenerative disorder characterized by memory loss and cognitive functions decline, is a leading cause for dementia and currently ranked as the sixth foremost cause of death. As of present, treatment of AD is symptomatic without convincing therapeutic benefits and new, effective, therapeutic agents are pursued. Due to massive loss of cholinergic neurons and decreased acetylcholine levels, cholinesterase inhibitors like galantamine, remain the backbone of pharmacological treatment of the disease. In the present study, using behavioral and biochemical methods, four newly synthesized galantamine derivatives, Gal 34, Gal 43, Gal 44, and Gal 46, were evaluated for a beneficial effect in a scopolamine model of dementia in mice. They were designed to have all the advantages of galantamine and additionally to inhibit β-secretase and exert favorable effects on plasma lipids. Behavioral tests included step-through inhibitory avoidance, T-maze, and the hole-board test, whereas biochemical evaluations involved assessment of acetylcholinesterase activity, brain monoamines levels, lipid peroxidation, catalase, glutathione peroxidase, and superoxide dismutase activities along with measurement of total glutathione. Results show that Gal 43, Gal 44, and, in particular, Gal 46 are especially effective in improving both short- and long-term memory and in the case of Gal 46 having a significant effect on exploratory activity as well. Although Gal 34 did not show behavioral effects as convincing as those of the other three galantamine derivatives, it demonstrated persuasive antioxidant and restorative capacities, making all four galantamine derivatives promising AD treatment agents and prompting further research, especially that in many of our studies they performed better than galantamine.

The Biology and Pathobiology of Glutamatergic, Cholinergic, and Dopaminergic Signaling in the Aging Brain

The elderly population is growing worldwide, with important health and socioeconomic implications. Clinical and experimental studies on aging have uncovered numerous changes in the brain, such as decreased neurogenesis, increased synaptic defects, greater metabolic stress, and enhanced inflammation. These changes are associated with cognitive decline and neurobehavioral deficits. Although aging is not a disease, it is a significant risk factor for functional worsening, affective impairment, disease exaggeration, dementia, and general disease susceptibility. Conversely, life events related to mental stress and trauma can also lead to accelerated age-associated disorders and dementia. Here, we review human studies and studies on mice and rats, such as those modeling human neurodegenerative diseases, that have helped elucidate (1) the dynamics and mechanisms underlying the biological and pathological aging of the main projecting systems in the brain (glutamatergic, cholinergic, and dopaminergic) and (2) the effect of defective glutamatergic, cholinergic, and dopaminergic projection on disabilities associated with aging and neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases. Detailed knowledge of the mechanisms of age-related diseases can be an important element in the development of effective ways of treatment. In this context, we briefly analyze which adverse changes associated with neurodegenerative diseases in the cholinergic, glutaminergic and dopaminergic systems could be targeted by therapeutic strategies developed as a result of our better understanding of these damaging mechanisms.

Effects of GrandFusion Diet on Cognitive Impairment in Transgenic Mouse Model of Alzheimer's Disease

Alzheimer’s disease (AD) is the result of the deposition of amyloid β (Aβ) peptide into amyloid fibrils and tau into neurofibrillary tangles. At the present time, there are no possible treatments for the disease. We have recently shown that diets enriched in phytonutrients show protection or limit the extent of damage in a number of neurological disorders. GrandFusion (GF) diets have attenuated the outcomes in animal models of traumatic brain injury, cerebral ischemia, and chronic traumatic encephalopathy. In this study, we investigated the effect of GF diets in a mouse model of AD prior to the development of amyloid plaques to show how this treatment paradigm would alter the accumulation of Aβ peptide and related pathologic changes (i.e., inflammation, cathepsin B, and memory impairment). Administration of GF diets (2–4%) over a period of four months in APP/ΔPS1 double-transgenic mice resulted in attenuation in Aβ peptide levels, reduction of amyloid load, and inflammation, increased cathepsin B expression, and improved spatial orientation. Additionally, treatment with GF diets increased nerve growth factor (NGF) levels in the brain and tempered the memory impairment in the animal model. These data suggest that GF diets may alter the development and progression of the mechanisms associated with the disease process to effectively modify AD pathogenesis.

Multi-Target Drug Candidates for Multifactorial Alzheimer's Disease: AChE and NMDAR as Molecular Targets

Alzheimer's disease (AD) is one of the most common forms of dementia among elder people, which is a progressive neurodegenerative disease that results from a chronic loss of cognitive activities. It has been observed that AD is multifactorial, hence diverse pharmacological targets that could be followed for the treatment of AD. The Food and Drug Administration has approved two types of medications for AD treatment such as cholinesterase inhibitors (ChEIs) and N-methyl-D-aspartic acid receptor (NMDAR) antagonists. Rivastigmine, donepezil, and galantamine are the ChEIs that have been approved to treat AD. On the other hand, memantine is the only non-competitive NMDAR antagonist approved in AD treatment. As compared with placebo, it has been revealed through clinical studies that many single-target therapies are unsuccessful to treat multifactorial Alzheimer's symptoms or disease progression. Therefore, due to the complex nature of AD pathophysiology, diverse pharmacological targets can be hunted. In this article, based on the entwined link of acetylcholinesterase (AChE) and NMDAR, we represent several multifunctional compounds in the rational design of new potential AD medications. This review focus on the significance of privileged scaffolds in the generation of the multi-target lead compound for treating AD, investigating the idea and challenges of multi-target drug design. Furthermore, the most auspicious elementary units for designing as well as synthesizing hybrid drugs are demonstrated as pharmacological probes in the rational design of new potential AD therapeutics.

Smartphone technology for fostering goal-directed ambulation and object use in people with moderate Alzheimer's disease

Purpose: This study was aimed at assessing a smartphone-based intervention to help 11 individuals with moderate Alzheimer's disease and ambulation problems to manage goal-directed, walker-assisted ambulation and object use (i.e., to reach specific destinations and put away objects at those destinations independently).Method: The study was carried out according to a non-concurrent multiple baseline design across participants. Two measures were recorded, that is, the number of target responses performed correctly (with each target response consisting of reaching a destination and putting away an object), and the number of observation intervals with indices of enjoyment/appreciation (e.g., smiles and positive comments). During baseline, the participants were provided with a walker and three objects that were to be transported to and put away at specific destinations. During the intervention, the participants also had the smartphone-based technology that provided them with instructions about the destinations and objects, praise, and preferred stimulation.Results: During baseline, the mean frequency of correct target responses was virtually zero. The mean frequency of intervals with indices of enjoyment/appreciation ranged from zero to close to one. During the intervention, the mean frequencies for the two measures were slightly below three and just over three, respectively. The maximum frequencies possible were three and four, respectively.Conclusions: A smartphone-based intervention may be suitable to foster goal-directed, walker-assisted ambulation and object use as well as enjoyment/appreciation in participants like those involved in this study.IMPLICATIONS FOR REHABILITATIONA smartphone-based intervention may be used to promote goal-directed, walker-assisted ambulation and object use as well as indices of enjoyment/appreciation in persons with moderate Alzheimer disease.The technology for such intervention might involve (a) a smartphone with Android operating system, light sensor, Bluetooth v4.0, and MacroDroid, (b) Bluetooth headphones or earpieces, and (c) battery-powered light sources.The technology may provide the participants with instructions about the destinations to reach and the objects to put away at those destinations, and with praise and brief periods of preferred stimulation at the target destinations.The technology may be considered easy to access, friendly for the participants, and suitable for use by staff within daily contexts.

Pharmacokinetics and Bioequivalence of Memantine Tablet and a New Dry Syrup Formulation in Healthy Japanese Males: Two Single-Dose Crossover Studies

Introduction

Memantine hydrochloride, an N-methyl-D-aspartate receptor antagonist, is used to treat Alzheimer’s disease (AD). A new dry syrup formulation containing memantine hydrochloride has been developed to improve medication adherence in AD patients and to reduce family and caregiver burden. This study was conducted to assess the bioequivalence of this new formulation to the tablet.

Methods

Two single-dose, randomized, open-label, two-period, two-group, crossover studies were conducted to assess the bioequivalence of a test product [dry syrup, 2%, 1 g (containing 20 mg of memantine hydrochloride)] to a reference product (film-coated tablet) under two dosing conditions: administration of the test product as a suspension in water (Study I) and as granules taken with water (Study II). Blood samples were collected at specified time intervals, and memantine plasma concentrations were determined using a validated liquid chromatography tandem mass spectrometry method. The pharmacokinetic parameters of memantine were calculated using non-compartmental analysis. The maximum concentration (C_max) and area under the concentration–time curve up to the last sampling time (AUC_all) were used to assess the bioequivalence of the two formulations.

Results

The geometric least square mean (GLSM) ratios [90% confidence interval (CI)] of the C_max and AUC_all of memantine for the test product to the reference product were 0.981 (0.943–1.020) and 0.978 (0.955–1.001) in Study I, and 0.973 (0.944–1.003) and 1.004 (0.983–1.025) in Study II, respectively. In both studies, the 90% CI values of the GLSM ratios of C_max and AUC_all were within the prespecified bioequivalence range (0.80–1.25). The safety of the test product under both dosing conditions and that of the reference product were not different.

Conclusions

The new dry syrup formulation containing memantine hydrochloride showed bioequivalence to the film-coated tablet under the two dosing conditions. Thus, the new dry syrup is suitable under either dosing condition for patients with AD.

Funding

Daiichi Sankyo Co., Ltd.