Journal of Alzheimer's Disease - Volume 101, issue s1

Authors: Pappolla, Miguel A. | Martins, Ralph N. | Poeggeler, Burkhard | Omar, Rawhi A. | Perry, George

Article Type: Review Article

Abstract: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by gradual and progressive cognitive decline leading to dementia. At its core, the neuropathological features of AD include hallmark accumulations of amyloid-β and hyperphosphorylated tau proteins. Other harmful processes, such as oxidative stress and inflammation, contribute to the disease’s neuropathological progression. This review evaluates the role of oxidative stress in AD, placing a spotlight on the disappointing outcomes of various antioxidant clinical trials. Several hypotheses are discussed that might elucidate the failures of these therapies in AD. Specifically: 1) The paradoxical and overlooked harmful implications of prooxidant intermediates, particularly stemming from conventional …antioxidants like vitamins E and C; 2) The challenges and failure to appreciate the issue of bioavailability—epitomized by the dictum “no on-site protection, no protection”—and the preeminent, yet often ignored, role played by endogenous antioxidant enzymes in combating oxidative stress; 3) The influence of unrecognized etiologies, such as latent infectious agents and others, as foundational drivers of oxidative stress in AD; 4) The underestimation of the complexity of oxidative mechanisms and the necessity of multi-targeted therapeutic approaches, such as those provided by various diets; and 5) The limitations of clinical trial designs in fully capturing the effects of antioxidants on AD progression. This article also examines the outcomes of select clinical trials while highlighting the challenges and barriers these therapies pose, offering insights into potential mechanisms to overcome their marginal success. Show more

Keywords: Alzheimer’s disease, clinical trials, DASH diet, Mediterranean diet, melatonin, MIND diet, oxidative stress, resveratrol, vitamin E, vitamin C

DOI: 10.3233/JAD-240659

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S155-S178, 2024

Authors: Currais, Antonio | Raschke, William | Maher, Pamela

Article Type: Review Article

Abstract: Old age is the major risk factor for sporadic Alzheimer’s disease (AD). However, old age-related changes in brain physiology have generally not been taken into consideration in developing drug candidates for the treatment of AD. This is at least partly because the role of these age-related processes in the development and progression of AD are still not well understood. Nevertheless, we and others have described an association between the oxytosis/ferroptosis non-apoptotic regulated cell death pathway and aging. Based on this association, we incorporated protection against this pathway as part of a cell-based phenotypic screening approach to identify novel drug candidates …for the treatment of AD. Using this approach, we identified the fisetin derivative CMS121 as a potent neuroprotective molecule that is able to maintain cognitive function in multiple pre-clinical models of AD. Furthermore, we identified a key target of CMS121 as fatty acid synthase, a protein which had not been previously considered in the context of AD. Herein, we provide a comprehensive description of the development of CMS121, its preclinical activities, and the results of the toxicology testing that led to its IND approval. Show more

Keywords: Acetyl CoA, Alzheimer’s disease, AMP-activated kinase, fatty acid synthase, mitochondria, oxytosis/ferroptosis

DOI: 10.3233/JAD-231062

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S179-S192, 2024

Authors: Steinbach, Marilyn J. | Denburg, Natalie L.

Article Type: Review Article

Abstract: There are currently no effective treatments to prevent, halt, or reverse Alzheimer’s disease (AD), the most common cause of dementia in older adults. Melatonin, a relatively harmless over-the-counter supplement, may offer some benefits to patients with AD. Melatonin is known for its sleep-enhancing properties, but research shows that it may provide other advantages as well, such as antioxidant and anti-amyloidogenic properties. Clinical trials for melatonin use in AD have mixed results but, overall, show modest benefits. However, it is difficult to interpret clinical research in this area as there is little standardization to guide the administration and study of melatonin. …This review covers basic biology and clinical research on melatonin in AD focusing on prominent hypotheses of pathophysiology of neurodegeneration and cognitive decline in AD (i.e., amyloid and tau hypotheses, antioxidant and anti-inflammation, insulin resistance and glucose homeostasis, the cholinergic hypothesis, sleep regulation, and the hypothalamic-pituitary-adrenal axis and cortisol). This is followed by a discussion on pending clinical trials, considerations for future research protocols, and open questions in the field. Show more

Keywords: Aging, Alzheimer’s disease, circadian rhythm, clinical trials, dementia, melatonin, sleep

DOI: 10.3233/JAD-230760

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S193-S204, 2024

Authors: Eyob, Estelle | Shaw, Jacob S. | Bakker, Arnold | Munro, Cynthia | Spira, Adam | Wu, Mark | Rabinowitz, Jill A. | Peters, Matthew | Wanigatunga, Sarah | Zipunnikov, Vadim | Thompson, Richard | Burhanullah, M. Haroon | Leoutsakos, Jeannie-Marie | Rosenberg, Paul | Greenberg, Barry

Article Type: Research Article

Abstract:  Alzheimer’s disease (AD) is a leading cause of mortality and morbidity among aging populations worldwide. Despite arduous research efforts, treatment options for this devastating neurodegenerative disease are limited. Sleep disturbances, through their link to changes in neural excitability and impaired clearance of interstitial abnormal protein aggregates, are a key risk factor for the development of AD. Research also suggests that the neuroprotective effects of sleep are particularly active during slow wave sleep. Given the strong link between sleep disturbance and AD, targeting sleep in the prodromal stages of AD, such as in mild cognitive impairment (MCI), represents a promising avenue …for slowing the onset of AD-related cognitive decline. In efforts to improve sleep in older individuals, several pharmacologic approaches have been employed, but many pose safety risks, concern for worsening cognitive function, and fail to effectively target slow wave sleep. Trazodone, a safe and widely used drug in the older adult population, has shown promise in inducing slow wave sleep in older adults, but requires more rigorous research to understand its effects on sleep and cognition in the prodromal stages of AD. In this review, we present the rationale and study design for our randomized, double-bind, placebo-controlled, crossover trial (NCT05282550) investigating the effects of trazodone on sleep and cognition in 100 older adults with amnestic MCI and sleep complaints. Show more

Keywords: Alzheimer’s disease, circadian rhythms, hippocampus, mild cognitive impairment, sleep, trazodone

DOI: 10.3233/JAD-230635

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S205-S215, 2024

Authors: Kuck, M.J. | Begde, Ahmet | Hawkins, Katie | Hogervorst, Eef

Article Type: Review Article

Abstract: Background: There is a continued debate on whether menopausal hormone therapy (MHT) protects women against Alzheimer’s disease (AD). It is also unclear whether phytoestrogen could be an alternative treatment for AD. Objective: To investigate whether mixed study findings may be due to differences in age at initiation of MHT and duration of prescription of different types of MHT using meta-analyses. Methods: After a systematic literature search, meta-analyses were carried out using Cochrane Revman 5.4.1.software including data from large nationwide studies of registered medically diagnosed AD and prescribed MHT. These analyses were stratified for duration and type …of treatment, by age at start of prescription of therapy. Insufficient quality data were available for phytoestrogen treatment and AD meta-analyses. Results: A total of 912,157 women were included from five registries, of whom 278,495 had developed AD during follow-up. Meta-analyses suggested a small increased AD risk after 5–10 years prescription of combination MHT regardless of age, and over 10 years only in women younger than 60 years of age. No association was seen for estrogen alone for women younger than 60 years of age, but AD risk did increase for women over 60 years of age for up to 5 years of MHT prescriptions. Conclusions: Combination MHT should probably be prescribed for less than 5 years after menopause to reduce risk for AD, while estrogen alone should not be prescribed to women over 60. For phytoestrogen, small treatment trials suggested some benefit of tempeh (fermented soy), which should be investigated further. Show more

Keywords: Alzheimer’s disease risk, estrogen, hormone therapy, memory, menopause, meta-analyses

DOI: 10.3233/JAD-231415

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S217-S234, 2024

Authors: Sayfullaeva, Jessica | McLoughlin, John | Kwakowsky, Andrea

Article Type: Review Article

Abstract: Alzheimer’s disease (AD) is a progressive neurodegenerative disorder responsible for over half of dementia cases, with two-thirds being women. Growing evidence from preclinical and clinical studies underscores the significance of sex-specific biological mechanisms in shaping AD risk. While older age is the greatest risk factor for AD, other distinct biological mechanisms increase the risk and progression of AD in women including sex hormones, brain structural differences, genetic background, immunomodulation and vascular disorders. Research indicates a correlation between declining estrogen levels during menopause and an increased risk of developing AD, highlighting a possible link with AD pathogenesis. The neuroprotective effects of …estrogen vary with the age of treatment initiation, menopause stage, and type. This review assesses clinical and observational studies conducted in women, examining the influence of estrogen on cognitive function or addressing the ongoing question regarding the potential use of hormone replacement therapy (HRT) as a preventive or therapeutic option for AD. This review covers recent literature and discusses the working hypothesis, current use, controversies and challenges regarding HRT in preventing and treating age-related cognitive decline and AD. The available evidence indicates that estrogen plays a significant role in influencing dementia risk, with studies demonstrating both beneficial and detrimental effects of HRT. Recommendations regarding HRT usage should carefully consider the age when the hormonal supplementation is initiated, baseline characteristics such as genotype and cardiovascular health, and treatment duration until this approach can be more thoroughly investigated or progress in the development of alternative treatments can be made. Show more

Keywords: Alzheimer’s disease, cognition, dementia, estradiol, estrogen, hormone replacement therapy, hormone therapy, memory

DOI: 10.3233/JAD-240899

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S235-S261, 2024

Authors: Sun, Miao-Kun | Alkon, Daniel L.

Article Type: Review Article

Abstract: Neurodegenerative disorders involve progressive dysfunction and loss of synapses and neurons and brain atrophy, slowly declining memories and cognitive skills, throughout a long process. Alzheimer’s disease (AD), the leading neurodegenerative disorder, suffers from a lack of effective therapeutic drugs. Decades of efforts targeting its pathologic hallmarks, amyloid plaques and neurofibrillary tangles, in clinical trials have produced therapeutics with marginal benefits that lack meaningful clinical improvements in cognition. Delivering meaningful clinical therapeutics to treat or prevent neurodegenerative disorders thus remains a great challenge to scientists and clinicians. Emerging evidence, however, suggests that dysfunction of various synaptogenic signaling pathways participates in the …neurodegenerative progression, resulting in deterioration of operation/structure of the synaptic networks involved in cognition. These derailed endogenous signaling pathways and disease processes are potential pharmacological targets for the therapies. Therapeutics with meaningful clinical benefit in cognition may depend on the effectiveness of arresting and reversing the neurodegenerative process through these targets. In essence, promoting neuro-regeneration may represent the only option to recover degenerated synapses and neurons. These potential directions in clinical trials for AD therapeutics with meaningful clinical benefit in cognitive function are summarized and discussed. Show more

Keywords: Alzheimer’s disease, brain-derived neurotrophic factor, cognitive therapy, meaningful clinical benefit, neuroinflammation, neuropharmacology, protein kinase Cɛ

DOI: 10.3233/JAD-240479

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S263-S274, 2024

Authors: Viña, José | Borrás, Consuelo | Mas-Bargues, Cristina

Article Type: Review Article

Abstract: Alzheimer’s disease is recognized as a complex condition influenced by multiple factors, necessitating a similarly multifaceted approach to treatment. Ideally, interventions should prioritize averting the progression to dementia. Given the chronic nature of the disease, long-term management strategies are required. Within this framework, lifestyle modifications and dietary supplements emerge as appealing options due to their minimal toxicity, limited side effects, and cost-effectiveness. This study presents findings from a double-blind, placebo-controlled bicentric pilot clinical trial, demonstrating the significant cognitive preservation associated with genistein, a phytoestrogen found in soy and various other dietary sources, among individuals with prodromal Alzheimer’s disease. Our prior …investigation utilizing APP/PS1 mice elucidated the specific mechanisms through which genistein operates, including anti-amyloid-β, antioxidant, anti-inflammatory, and antiapoptotic effects. These findings underscore the potential of identifying bioactive compounds from dietary sources for the management of Alzheimer’s disease. Show more

Keywords: Aging, Alzheimer’s disease, dementia, genistein, soya supplements, treatment.

DOI: 10.3233/JAD-240308

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S275-S283, 2024

Authors: Morató, Xavier | Tartari, Juan Pablo | Pytel, Vanesa | Boada, Mercè

Article Type: Review Article

Abstract: Extracts made from plants are complex mixtures of substances with varying compositions depending on the plant material and method of manufacture. This complexity makes it difficult for scientists and clinicians to interpret findings from pharmacological and clinical research. We performed a narrative review summarizing information on ginkgo biloba leaf extract, its composition, pharmacological data and clinical evidence supporting its administration for the treatment of Alzheimer’s disease (AD). Medicinal products containing ginkgo biloba leaf extract which are manufactured in compliance with the requirements of the European Pharmacopoeia are approved as medicinal products for the treatment of dementia and related conditions by …drug regulatory agencies in Europe, Asia and South America. As multicomponent mixtures, they may affect various targets in the pathogenesis of AD, the most common form of dementia. Pharmacodynamic studies demonstrate the effects of EGb 761 and individual constituents on various pathophysiological features of experimentally induced cognitive impairment and neurodegeneration that could contribute to its clinical efficacy. The safety and efficacy in the treatment of AD and cognitive decline has been studied in randomized, placebo-controlled clinical trials. Most of the studies that investigate the effects of ginkgo biloba extract (GbE) used the special extract EGb 761, which makes it the best-researched plant preparation worldwide. It is therefore the only herbal alternative to standard-of-care anti-dementia drugs. However, the mechanism of action has not been fully elucidated yet, and the clinical studies in AD show heterogeneity. Show more

Keywords: Alzheimer’s disease clinical studies, EGb 761, Ginkgo biloba L. extract, pharmacological studies

DOI: 10.3233/JAD-231372

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S285-S298, 2024

Authors: Roberts, Jackson A. | Varma, Vijay R. | Jones, Attila | Thambisetty, Madhav

Article Type: Review Article

Abstract: Drug repurposing is a methodology used to identify new clinical indications for existing drugs developed for other indications and has been successfully applied in the treatment of numerous conditions. Alzheimer’s disease (AD) may be particularly well-suited to the application of drug repurposing methods given the absence of effective therapies and abundance of multi-omic data that has been generated in AD patients recently that may facilitate discovery of candidate AD drugs. A recent focus of drug repurposing has been in the application of pharmacoepidemiologic approaches to drug evaluation. Here, real-world clinical datasets with large numbers of patients are leveraged to establish …observational efficacy of candidate drugs for further evaluation in disease models and clinical trials. In this review, we provide a selected overview of methods for drug repurposing, including signature matching, network analysis, molecular docking, phenotypic screening, semantic network, and pharmacoepidemiological analyses. Numerous methods have also been applied specifically to AD with the aim of nominating novel drug candidates for evaluation. These approaches, however, are prone to numerous limitations and potential biases that we have sought to address in the Drug Repurposing for Effective Alzheimer’s Medicines (DREAM) study, a multi-step framework for selection and validation of potential drug candidates that has demonstrated the promise of STAT3 inhibitors and re-evaluated evidence for other drug candidates, such as phosphodiesterase inhibitors. Taken together, drug repurposing holds significant promise for development of novel AD therapeutics, particularly as the pace of data generation and development of analytical methods continue to accelerate. Show more

Keywords: Alzheimer’s disease, clinical trials, drug repositioning, drug repurposing, metabolomics, pharmacoepidemiology, proteomics

DOI: 10.3233/JAD-240680

Citation: Journal of Alzheimer's Disease, vol. 101, no. s1, pp. S299-S315, 2024