Abstract Alzheimer's disease (AD) is the most common type of dementia in the elderly. Products of oxidative and nitrosative stress (OS and NS, respectively) accumulate with aging, which is the main ...risk factor for AD. This provides the basis for the involvement of OS and NS in AD pathogenesis. OS and NS occur in biological systems due to the dysregulation of the redox balance, caused by a deficiency of antioxidants and/or the overproduction of free radicals. Free radical attack against lipids, proteins, sugars and nucleic acids leads to the formation of bioproducts whose detection in fluids and tissues represents the currently available method for assessing oxidative/nitrosative damage. Post-mortem and in-vivo studies have demonstrated an accumulation of products of free radical damage in the central nervous system and in the peripheral tissues of subjects with AD or mild cognitive impairment (MCI). In addition to their individual role, biomarkers for OS and NS in AD are associated with altered bioenergetics and amyloid-beta (Aβ) metabolism. In this review we discuss the main results obtained in the field of biomarkers of oxidative/nitrosative stress in AD and MCI in humans, in addition to their potential role as a tool for diagnosis, prognosis and treatment efficacy in AD.
Background: Inflammation, along with aging processes, contributes to the development of insulin resistance (IR), but the roles of different inflammatory and other cytokines in this process remain ...unclear. Thus, we aimed to analyze the association between several plasma cytokines with IR as evaluated by the metabolic score for insulin resistance, METS-IR. Methods: We measured the plasma concentrations of thirty cytokines from a cohort of older persons and analyzed their role as independent factors for IR. We used regression analyses adjusted for known IR-associated factors (including age, gender, cholesterol levels, and BMI) to find the determinants of IR. Results: The study evaluated 132 subjects, mostly women (82F/50M), slightly overweight, and with a mean age of 78.5 ± 6.5 years. In the overall population, IL-15 significantly and negatively correlates with METS-IR (r = −0.183, p = 0.036). A regression model showed that the association between IL-15 and METS-IR was significantly modulated by gender and BMI (R2: 0.831). Only in women, EGF, Eotaxin and MCP-1 significantly correlated with METS-IR even after controlling by age (EGF, r = 0.250 p = 0.025; Eotaxin, r = 0.276 p = 0.13; MCP-1, r = 0.237, p = 0.033). Furthermore, regression models showed that these molecules were associated with METS-IR and were strongly mediated by BMI. Conclusions: Our results indicate the association between cytokines and IR has to be interpreted in a gender-specific manner. In women, EGF, Eotaxin, and MCP-1 circulating levels are associated with METS-IR being BMI a significant mediator. Understanding the role of gender in the relationship between cytokines and IR will help to define individualized preventive and treatment interventions to reduce the risk of age-related metabolic disorders.
Alzheimer's disease (AD) is the most frequent cause of dementia worldwide and represents one of the leading factors for severe disability in older persons. Although its etiology is not fully known ...yet, AD may develop due to multiple factors, including inflammation and oxidative stress, conditions where microRNAs (miRNAs) seem to play a pivotal role as a molecular switch. All these aspects may be modulated by nutritional factors. Among them, vitamin E has been widely studied in AD, given the plausibility of its various biological functions in influencing neurodegeneration. From a cohort of old-aged people, we measured eight vitamin E forms (tocopherols and tocotrienols), thirty cytokines/chemokines, and thirteen exosome-extracted miRNAs in plasma of subjects suffering from subjects affected by AD and age-matched healthy controls (HC). The sample population included 80 subjects (40 AD and 40 HC) with a mean age of 77.6 ± 3.8 years, mostly women (45; 56.2%). Of the vitamin E forms, only α-tocopherol differed between groups, with significantly lower levels in AD. Regarding the examined inflammatory molecules, G-CSF, GM-CSF, INF-α2, IL-3, and IL-8 were significantly higher and IL-17 lower in AD than HC. Among all miRNAs examined, AD showed downregulation of miR-9, miR-21, miR29-b, miR-122, and miR-132 compared to controls. MiR-122 positively and significantly correlated with some inflammatory molecules (GM-CSF, INF-α2, IL-1α, IL-8, and MIP-1β) as well as with α-tocopherol even after correction for age and gender. A final binary logistic regression analysis showed that α-tocopherol serum levels were associated with a higher AD probability and partially mediated by miR-122. Our results suggest an interplay between α-tocopherol, inflammatory molecules, and microRNAs in AD, where miR-122 may be a good candidate as modulating factor.
Alzheimer disease (AD) is an age-related neurodegenerative condition. AD is histopathologically characterized by the presence of three main hallmarks: senile plaques (rich in amyloid-β peptide), ...neuronal fibrillary tangles (rich in phosphorylated tau protein), and synapse loss. However, definitive biomarkers for this devastating disease in living people are still lacking. In this study, we show that levels of oxidative stress markers are significantly increased in the mitochondria isolated from lymphocytes of subjects with mild cognitive impairment (MCI) compared to cognitively normal individuals. Further, an increase in mitochondrial oxidative stress in MCI is associated with MMSE score, vitamin E components, and β-carotene. Further, a proteomics approach showed that alterations in the levels of thioredoxin-dependent peroxide reductase, myosin light polypeptide 6, and ATP synthase subunit β might be important in the progression and pathogenesis of AD. Increased understanding of oxidative stress and protein alterations in easily obtainable peripheral tissues will be helpful in developing biomarkers to combat this devastating disorder.
BACKGROUND: Evidence that vitamin E may preserve cognitive function in elderly subjects is conflicting. The most abundant and most investigated form of vitamin E in humans is α-tocopherol, but other ...antioxidant tocopherols (β, γ, and δ) exist in nature. OBJECTIVE: We aimed to investigate plasma concentrations of the natural tocopherols and the tocopherol oxidation markers α-tocopherylquinone (αTQ) and 5-nitro-γ-tocopherol (5NGT) in relation to cognitive function in the elderly. DESIGN: Baseline plasma tocopherols and their oxidation markers were measured in 761 elderly Italian subjects from a population-based cohort assessed in 1999-2000 for mild cognitive impairment (MCI) and dementia. In 2003-2004, information about cognitive status was collected for 615 of the 666 subjects without baseline cognitive impairment. Tocopherols and oxidation markers were analyzed as plasma absolute values divided by serum total cholesterol because lipids affect their blood availability. Analyses were adjusted for sociodemographic, genetic, lifestyle, and medical confounders. RESULTS: Compared with the corresponding lowest tertile, the risk of prevalent dementia was higher for the highest tertile of δ-tocopheroldivide signcholesterol odds ratio (OR): 3.87; 95% CI: 1.46, 10.27 and αTQdivide signcholesterol (4.02; 1.45, 11.14), but the risk of incident dementia was not directly associated with plasma vitamin E metabolites. A U-shaped association, with lower risk for intermediate tertiles, was found for prevalent MCI with 5NGTdivide signcholesterol (0.39; 0.17, 0.91) and for incident dementia with γ-tocopheroldivide signcholesterol (hazard ratio: 0.42; 95% CI: 0.22, 0.84). CONCLUSIONS: Plasma concentrations of some non-α-tocopherol forms of vitamin E are associated with cognitive impairment in elderly people. However, the associations depend on concurrent cholesterol concentration and need further investigation.
Interest in data on violence against children has been gathering momentum in recent years. Nevertheless, data collection efforts overall are sporadic and national data systems remain underdeveloped. ...What is more, definitions of violence are inconsistent and unclear. What ‘counts’ as violence against children varies across data collection efforts, negatively impacting data quality. Significant investment – in the form of guidance as well as tools and other resources for capacity-building – is urgently required to respond to countries' data needs. The newly released International Classification of Violence against Children (ICVAC) holds potential for bringing the world one step closer to filling data gaps and thus promoting accountability towards the ambitious global goal of ending violence against children.
The Editors of the Journal of Alzheimer's Disease invited Professor Patrizia Mecocci to contribute a review article focused on the importance and implications of her research on aging, brain aging, ...and senile dementias over the last years. This invitation was based on an assessment that she was one of the journal's top authors and a strong supporter of the concept that oxidative stress is a major contributor to several alterations observed in age-related conditions (sarcopenia, osteoporosis) and, more significantly, in brain aging suggesting a pivotal role in the pathogenesis and progression of one of the most dramatic age-related diseases, Alzheimer's disease (AD). Her first pioneering research was on the discovery of high level of 8-hydroxy-2'-deoxyguanosine (OH8dG), a marker of oxidation in nucleic acids, in mitochondrial DNA isolated from cerebral cortex. This molecule increases progressively with aging and more in AD brain, supporting the hypothesis that oxidative stress, a condition of unbalance between the production of reactive oxygen species and antioxidants, gives a strong contribution to the high incidence of AD in old age subjects. OH8dG also increases in peripheral lymphocyte from AD subjects, suggesting that AD is not only a cerebral but also a systemic disease. The role of antioxidants, particularly vitamin E and zinc, were also studied in longevity and in cognitive decline and dementia. This review shows the main findings from Mecocci's laboratory related to oxidative stress in aging, brain aging, and AD and discusses the importance and implications of some of the major achievements in this field of research.
Experimental studies provide evidence of an association between ischemic stroke and increased oxidative stress, but data in humans are still limited and controversial. The purpose of this study was ...to investigate the time course of plasma antioxidant changes in ischemic stroke patients.
Plasma antioxidants, including water-soluble (vitamin C and uric acid) and lipid-soluble (vitamins A and E) compounds as well as antioxidant enzyme activities in plasma (superoxide dismutase SOD and glutathione peroxidase) and erythrocytes (SOD), were measured by high-performance liquid chromatography (antioxidant vitamins) and by spectrophotometry (antioxidant enzymes) in 38 subjects (25 men and 13 women aged 77.2+/-7.9 years) with acute ischemic stroke of recent onset (<24 hours) on admission, after 6 and 24 hours, and on days 3, 5, and 7. Antioxidant levels in patients on admission were compared with those of age- and sex-matched controls.
Mean antioxidant levels and activities in patients on admission were lower than those of controls and showed a gradual increase over time. Patients with the worst early outcome (death or functional decline) had higher vitamin A and uric acid plasma levels and lower vitamin C levels and erythrocyte SOD activity than those who remained functionally stable.
These results suggest that the majority of antioxidants are reduced immediately after an acute ischemic stroke, possibly as a consequence of increased oxidative stress. A specific antioxidant profile is associated with a poor early outcome.
A large body of experimental research indicates that oxidative stress contributes to the processes related to aging and to the pathogenesis of several age-related diseases. Vitamins and antioxidant ...enzymes have a fundamental role in defending the organism from oxidative stress. To better understand the role of antioxidants in human aging, we measured plasma levels of vitamin C (ascorbic acid), uric acid, vitamin E (α-tocopherol), vitamin A (retinol), carotenoids, total thiol groups, and the activity of plasma superoxide dismutase (SOD) and glutathione peroxidase (GPX) as well as the activity of red blood cell (RBC) SOD in 32 healthy centenarians—17 elderly subjects aged 80–99 years, 34 elderly subjects aged 60–79 years, and 24 adults aged less than 60 years. Considering the “noncentenarians” only, we observed a consistent behavior in the antioxidant pattern, with a decrease of the nonenzymatic antioxidants and an increase of the enzymatic antioxidant activities relative to age. Remarkably, centenarians were characterized as having the highest levels of vitamins A and E, whereas the activities of both plasma and RBC SOD, which increase with age, decreased in centenarians. From these results, it is evident that healthy centenarians show a particular profile in which high levels of vitamin A and vitamin E seem to be important in guaranteeing their extreme longevity.
A large body of evidence supports a role of oxidative stress in Alzheimer disease (AD) and in cerebrovascular disease. A vascular component might be critical in the pathophysiology of AD, but there ...is a substantial lack of data regarding the simultaneous behavior of peripheral antioxidants and biomarkers of oxidative stress in AD and vascular dementia (VaD). Sixty-three AD patients, 23 VaD patients and 55 controls were included in the study. We measured plasma levels of water-soluble (vitamin C and uric acid) and lipophilic (vitamin E, vitamin A, carotenoids including lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha- and beta-carotene) antioxidant micronutrients as well as levels of biomarkers of lipid peroxidation malondialdehyde (MDA) and of protein oxidation immunoglobulin G (IgG) levels of protein carbonyls and dityrosine in patients and controls. With the exception of beta-carotene, all antioxidants were lower in demented patients as compared to controls. Furthermore, AD patients showed a significantly higher IgG dityrosine content as compared to controls. AD and VaD patients showed similar plasma levels of plasma antioxidants and MDA as well as a similar IgG content of protein carbonyls and dityrosine. We conclude that, independent of its nature-vascular or degenerative-dementia is associated with the depletion of a large spectrum of antioxidant micronutrients and with increased protein oxidative modification. This might be relevant to the pathophysiology of dementing disorders, particularly in light of the recently suggested importance of the vascular component in AD development.
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