Relationship of Physical Activity at Older Age with Biomarkers of Oxidative Stress: A Large, Population-based Cohort Study

Contribution of Physical Activity to the Oxidative and Antioxidant Potential in 60-65-Year-Old Seniors

Both acute exercise and regular physical activity (PA) are directly related to the redox system. However, at present, there are data suggesting both positive and negative relationships between the PA and oxidation. In addition, there is a limited number of publications differentiating the relationships between PA and numerous markers of plasma and platelets targets for the oxidative stress. In this study, in a population of 300 participants from central Poland (covering the age range between 60 and 65 years), PA was assessed as regards energy expenditure (PA-EE) and health-related behaviors (PA-HRB). Total antioxidant potential (TAS), total oxidative stress (TOS) and several other markers of an oxidative stress, monitored in platelet and plasma lipids and proteins, were then determined. The association of PA with oxidative stress was determined taking into the account basic confounders, such as age, sex and the set of the relevant cardiometabolic factors. In simple correlations, platelet lipid peroxides, free thiol and amino groups of platelet proteins, as well as the generation of superoxide anion radical, were inversely related with PA-EE. In multivariate analyses, apart from other cardiometabolic factors, a significant positive impact of PA-HRB was revealed for TOS (inverse relationship), while in the case of PA-EE, the effect was found to be positive (inverse association) for lipid peroxides and superoxide anion but negative (lower concentration) for free thiol and free amino groups in platelets proteins. Therefore, the impact of PA may be different on oxidative stress markers in platelets as compared to plasma proteins and also dissimilar on platelet lipids and proteins. These associations are more visible for platelets than plasma markers. For lipid oxidation, PA seems to have protective effect. In the case of platelets proteins, PA tends to act as pro-oxidative factor.

Association of F2-isoprostane levels with Alzheimer's disease in observational studies: A systematic review and meta-analysis

INTRODUCTION

The association between F₂-isoprostanes and Alzheimer's disease (AD) has been controversially discussed in the literature since the 1990s. However, no systematic review has been performed so far.

METHODS

A systematic review of observational studies on the associations of F₂-isoprostanes and the specific biomarker 8-iso-prostaglandin F_2α with AD were conducted. Random-effects model meta-analyses were performed.

RESULTS

29 studies were included in the systematic review, including four longitudinal studies. In an overall meta-analysis of the 25 cross-sectional studies, F₂-isoprostane levels were statistically significantly associated with AD (Hedge's g [95% confidence interval]: 1.00 [0.69-1.32]). When studies were grouped by biomarker and sample specimen, F₂-isoprostane and 8-iso-prostaglandin F_2α levels were statistically significantly elevated in tissue samples of the frontal lobe of AD patients. Moreover, F₂-isoprostane levels in cerebrospinal fluid and 8-iso-prostaglandin F_2α levels in blood samples of AD patients were significantly increased. Meta-analyses of the few longitudinal studies did not reach statistical significance.

DISCUSSION

Increased concentrations of F₂-isoprostanes were found in AD patients. However, due to the lack of adjustment in most cross-sectional case-control studies, results must be interpreted carefully. In addition, the causality of the association is uncertain because evidence from well-conducted longitudinal studies was conflicting, and further longitudinal studies are required to reinforce the results.