Alzheimer's disease (AD) is a highly disabling progressive neurodegenerative disorder characterized by a steadily growing number of patients, by the absence of a cure for the disease and by great ...difficulties in diagnosing in the preclinical phase. Progresses in defining the complex etiopathogenesis of AD consider oxidative stress a core aspect as far as both AD onset and progression are concerned. However, clinical trials of antioxidants in AD have brought conflicting conclusions. In this review, we report the main results of clinical trials with antioxidants in mild cognitive impairment (MCI) and AD. Although available data do not warrant the doubtless use of antioxidants in AD, they are characterized by extremely poor comparability and the absence of a substantial clinical benefit of antioxidants in AD is not disproved to date. Furthermore, the role of vascular damage that contributes to oxidative stress in AD should be addressed in testing antioxidant treatments. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.
► Oxidative damage is one of the main etiopathogenetic factors of Alzheimer's disease. ► Antioxidants have been proposed for AD prevention and therapy. ► Observational studies with dietary or supplemented antioxidants showed benefits. ► Clinical trials with antioxidants have led to conflicting results. ► New compounds alone or in association are under study in ongoing trials.
•Cellular senescence is the biological central mechanism for the major age-related diseases.•A large number of molecules, including synthetic senolytic and natural compounds contained in food, have ...been proposed for “anti-senescence” activities.•The lack of evidence, caution must be used against senolytic agents due to their potential effects.•Natural senolytic compounds should have the advantage of low toxicity and potentially more useful in humans.
The review aims to summarize and discuss the current knowledge on targeting senescent cells to reduce the risk of age-related diseases in animal models and human studies. The role of cellular senescence in aging and the major age-related diseases -including Alzheimer's disease, atherosclerosis, and type 2 diabetes- as well as the use of senotherapeutic strategies in both experimental and preclinical studies, will be described. A large number of molecules, including synthetic agents and natural compounds, have been proposed for anti-senescence activities. Research on senotherapeutics, which includes senolytic and senomorphic, has a growing interest, and their safety and reliability as anti-aging drugs have been tested in clinical trials. Initial findings suggest that the senotherapeutic approach may be translatable to humans. Due to the lack of evidence, caution must be used against senolytic agents due to their potential side-effects. In this context, natural senolytic compounds should have the advantage of low toxicity and potentially more useful in humans, although the mechanisms of action need to be defined.
Summary Alzheimer's disease is the most common cause of dementia in elderly people. Research into Alzheimer's disease therapy has been at least partly successful in terms of developing symptomatic ...treatments, but has also had several failures in terms of developing disease-modifying therapies. These successes and failures have led to debate about the potential deficiencies in our understanding of the pathogenesis of Alzheimer's disease and potential pitfalls in diagnosis, choice of therapeutic targets, development of drug candidates, and design of clinical trials. Many clinical and experimental studies are ongoing, but we need to acknowledge that a single cure for Alzheimer's disease is unlikely to be found and that the approach to drug development for this disorder needs to be reconsidered. Preclinical research is constantly providing us with new information on pieces of the complex Alzheimer's disease puzzle, and an analysis of this information might reveal patterns of pharmacological interactions instead of single potential drug targets. Several promising randomised controlled trials are ongoing, and the increased collaboration between pharmaceutical companies, basic researchers, and clinical researchers has the potential to bring us closer to developing an optimum pharmaceutical approach for the treatment of Alzheimer's disease.
Introduction
This study investigated the diagnostic and disease‐monitoring potential of plasma biomarkers in mild cognitive impairment (MCI) and Alzheimer's disease (AD) dementia and cognitively ...unimpaired (CU) individuals.
Methods
Plasma was analyzed using Simoa assays from 99 CU, 107 MCI, and 103 AD dementia participants.
Results
Phosphorylated‐tau181 (P‐tau181), neurofilament light, amyloid‐β (Aβ42/40), Total‐tau and Glial fibrillary acidic protein were altered in AD dementia but P‐tau181 significantly outperformed all biomarkers in differentiating AD dementia from CU (area under the curve AUC = 0.91). P‐tau181 was increased in MCI converters compared to non‐converters. Higher P‐tau181 was associated with steeper cognitive decline and gray matter loss in temporal regions. Longitudinal change of P‐tau181 was strongly associated with gray matter loss in the full sample and with Aβ measures in CU individuals.
Discussion
P‐tau181 detected AD at MCI and dementia stages and was strongly associated with cognitive decline and gray matter loss. These findings highlight the potential value of plasma P‐tau181 as a non‐invasive and cost‐effective diagnostic and prognostic biomarker in AD.
Alzheimer's disease (AD) represents the most common form of dementia among older age subjects, and despite decades of studies, the underlying mechanisms remain unresolved. The definition of AD has ...changed over the past 100 years, and while early-onset AD is commonly related to genetic mutations, late-onset AD is more likely due to a gradual accumulation of age-related modifications. "Normal brain aging" and AD may represent different pathways of successful or failed capability to adapt brain structures and cerebral functions. Cellular senescence and age-related changes (ARCs) affecting the brain may be considered as biologic manifestations of increasing entropy, a measure of disorder. Late-onset AD may be regarded as the final effect of a reduced energy production, due to exhausted mitochondria, and an increased entropy in the brain. This unique trajectory enables a bioenergetics-centered strategy targeting disease-stage specific profile of brain metabolism for disease prevention and treatment.
Background
Vitamin E represents a potent antioxidant and anti-inflammatory system, playing a role in Alzheimer’s disease (AD). Different plasma concentrations of the forms of vitamin E are observed ...in AD compared to cognitively healthy subjects.
Aim
Since these modifications may modulate the markers of oxidative stress and cellular aging, we aim to explore the relationship between vitamin E forms and leukocyte telomere length (LTL) in AD.
Methods
53 AD subjects and 40 cognitively healthy controls (CTs) were enrolled. The vitamin E forms (α-, β-, γ- and δ-tocopherol, α-, β-, γ- and δ-tocotrienol), the ratio of α-tocopherylquinone/α-tocopherol and 5-nitro-γ-tocopherol/γ-tocopherol (markers of oxidative/nitrosative damage) and LTL were measured.
Results and discussion
Regression model was used to explore the associations of vitamin E forms and LTL with AD. The interaction of LTL in the association between vitamin E forms and AD was tested. AD subjects showed significantly lower concentrations of α-, β-, γ- and δ-tocopherol, α- and δ-tocotrienol, total tocopherols, total tocotrienols and total vitamin E compared to CTs. AD subjects showed higher values of nitrosative/oxidative damage. The adjusted analyses confirmed a significant relationship of AD with plasma concentrations of α- and β-tocopherols, δ-tocotrienol, total tocopherols, total tocotrienol, total vitamin E and oxidative/nitrosative damage. However, nitrosative damage was significantly associated with AD only in subjects with higher LTL and not in those expressing marked cellular aging.
Conclusions
Our study confirms the role of vitamin E in AD pathology and indicates that nitrosative damage influences the association with AD only in subjects characterized by longer LTL.
The increasing life expectancy of populations worldwide represents the most evident success of the last century thanks to varying interacting social and medical achievements ....
The older Italian population is posing a challenge in the number of deaths for coronavirus disease 2019 (COVID-19). According to previous data from China, pre-existing health conditions dramatically ...increase the risk of dying from COVID-19. The presence of multiple diseases in older patients may be considered as a mark of frailty, which increases the person's vulnerability to stress and impairs the multisystemic compensatory effort to restore homeostasis. The clinical complexity associated with the management of frailty may increase the risk of complications during infection as well as the lack of the early recognition of atypical symptoms. There is an urgent need to share expertise and clinical management skills with geriatricians as well as the need for early diagnosis to start treatment at the earliest convenience in the community, with the aim to avoid the collapse of intensive care units.
Purpose
Advancing age represents the strongest risk factor for Alzheimer’s disease (AD), and the identification of biomarkers able to define what characterizes physiological aging from AD may ...represent a potential starting point for novel preventive strategies. Among these biomarkers, telomeres seem to be a promising target. Interestingly, high intake of carotenoid-rich food may play a role in protecting telomeres by oxidative stress reduction. Accordingly, low plasma β-carotene concentrations have been found in AD subjects when compared with cognitively healthy subjects. In this study, we aim at investigating the hypothesis that low β-carotene might be associated with markers of accelerated cellular aging, including leucocyte telomere length (LTL) and peripheral mononuclear cell (PBMC) telomerase activity in a cohort of old age subjects.
Methods
The study was conducted in 68 old age subjects, 37 AD, and 31 age-matched healthy controls. In all subjects, β-carotene plasma level, LTL and peripheral telomerase activity were measured.
Results
In all populations, β-carotene significantly and positively (
r
= 0.320,
p
= 0.008) correlated with telomerase activity, independent of gender. A model having telomerase activity levels as the dependent variable, and age, gender, smoking habit, and β-carotene as independent variables, confirmed that β-carotene was independently associated with telomerase activity (
β
= 0.319,
p
= 0.012). Subjects affected by AD had significantly lower plasmatic levels of β-carotene (448 ± 66 mg/ml vs 497 ± 59 mg/ml,
p
= 0.001) and LTL (0.53 ± 0.25 vs 0.69 ± 0.29;
p
= 0.009) as compared with healthy controls. Β-carotene plasma level was associated with AD diagnosis (OR 0.988; IC95% 0.978–0.997;
p
= 0.013) independently of age, gender, smoking habit, ApoE genotype, and LTL.
Conclusion
Our data show that β-carotene may modulate telomerase activity in old age. Moreover, lower plasma β-carotene levels, correlating with peripheral telomerase activity, are associated with AD diagnosis independent of multiple covariates.
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