Exercise, oxidative stress and risk of cardiovascular disease in the elderly. Protective role of antioxidant functional foods

Antioxidants Supplementation During Exercise: Friends or Enemies for Cardiovascular Homeostasis?

Exercise is a preferred strategy for improving cardiac function, especially for patients with cardiovascular diseases. Increasing evidence indicates that oxidative stress is involved in exercise-induced cardioprotection, while the underlying mechanism remains unclear. Furthermore, the effect of antioxidant supplementation during or post-exercise still exists despite divergences. To explore the effect of oxidative stress and antioxidant supplementation on cardiovascular homeostasis during or post-exercise, we take insights into the progress of exercise-induced oxidative stress, antioxidant supplementation, and cardiovascular homeostasis. In particular, antioxidants such as vitamin C or E, gamma-oryzanol, and other natural antioxidants are discussed concerning regulating exercise-associated oxidative stress. Additionally, our present study reviewed and discussed a meta-analysis of antioxidant supplementation during exercise. Overall, we take an insight into the essential biological adaptations in response to exercise and the effects of antioxidant supplementation on cardiac function, which aid us in giving recommendations on antioxidant supplementation for exercisers and exercised people. A better understanding of these issues will broaden our knowledge of exercise physiology.

Cardiac Oxidative Stress and the Therapeutic Approaches to the Intake of Antioxidant Supplements and Physical Activity

Reactive oxygen species (ROS) are strongly reactive chemical entities that include oxygen regulated by enzymatic and non-enzymatic antioxidant defense mechanisms. ROS contribute significantly to cell homeostasis in the heart by regulating cell proliferation, differentiation, and excitation-contraction coupling. When ROS generation surpasses the ability of the antioxidant defense mechanisms to buffer them, oxidative stress develops, resulting in cellular and molecular disorders and eventually in heart failure. Oxidative stress is a critical factor in developing hypoxia- and ischemia-reperfusion-related cardiovascular disorders. This article aimed to discuss the role of oxidative stress in the pathophysiology of cardiac diseases such as hypertension and endothelial dysfunction. This review focuses on the various clinical events and oxidative stress associated with cardiovascular pathophysiology, highlighting the benefits of new experimental treatments such as creatine supplementation, omega-3 fatty acids, microRNAs, and antioxidant supplements in addition to physical exercise

Association Between Diet Quality and Cardiorespiratory Fitness in Korean Adults: The 2014-2015 National Fitness Award Project

Cardiorespiratory fitness (CRF) is a strong and meaningful indicator for predicting mortality, including cardiovascular disease, as well as simple physical capacity. Healthy eating is thought to be one of the crucial factors associated with an individual's CRF status, although little research has been done on the relationship between healthy eating and CRF. This study aimed to investigate the association between overall diet quality and CRF among Korean adults. The study involved 937 adults (380 men and 557 women) aged 19‒64 years who participated in the 2014‒2015 Korea Institute of Sports Science Fitness Standards project. Diet quality was assessed by the recommended food score (RFS), and CRF was determined by maximal oxygen uptake (VO2max) during a treadmill exercise test. Multiple regression model analyses were stratified by age (19-34, 35-49, and 50-64 years) and sex, because both factors greatly influence CRF. After multivariate adjustment, only the 19‒34 age group in both sexes showed a positive association between RFS and VO2max. Additionally, when physical activity was adjusted, it was still significant in men but only marginally related in women. Our results suggest that better overall diet quality may be associated with a better CRF among young adults aged 19‒34 years in Korea.

Phytoecdysteroids from Ajuga iva act as potential antidiabetic agent against alloxan-induced diabetic male albino rats

The present study investigated the protective effect of phytoecdysteroids extracted from the Ajuga iva plant on body weight changes, blood glucose, insulin total protein, blood urea nitrogen (BUN), creatinine, triglycerides (TG), cholesterol, lipid peroxidation, antioxidant enzymes, pancreatic histopathology and hexokinase-I expression in the alloxan-induced diabetic rats. Experimental diabetes was induced following 15day intraperitoneal administration of alloxan. The rats were divided into four groups. Group I served as a sham group, and group II served as the diabetic control. Group III served as a treatment for phytoecdysteroids (10mg/kg), and group IV served as a treatment for phytoecdysteroids (20mg/kg). Phytoecdysteroids restored body weight loss to its antihyperglycemic effect. Blood glucose was reduced 19.2 and 52.9% in group III and IV respectively. Blood insulin (54.9 and 105.88%) and total protein (25 and 72.2%) was increased in group III and IV respectively. BUN, creatinine, TG, cholesterol and lipid peroxidation was significantly reduced following treatment. Catalase, superoxide dismutase (SOD), and glutathione peroxidase activity were significantly increased following treatment. Islet β-cells are lost in alloxan-induced diabetic rats. Regeneration of islets and reduced atrophy of acinar cells were noted. The number of insulin-secreting cells was tremendously reduced in alloxan-induced diabetic rats. Insulin-secreting cells were increased 48 and 61% in group III and IV respectively. Hexokinase-I mRNA (28.3 & 93.5%) and protein (27.9 and 55.3%) expression were significantly increased following treatment. Taking all these data together, it is suggested that the phytoecdysteroid could be a potential therapeutic agent against experimental diabetes.

In vitro antioxidant synergism and antagonism between food extracts can lead to similar activities in H2O2-induced cell death, caspase-3 and MMP-2 activities in H9c2 cells

BACKGROUND

The cardio-health-promoting activity of some foods may be due to their specific antioxidant content. The antioxidant activity of a mixture of plant extracts has been shown to differ from the activity of the individual extracts. As a result, the activity of the mixture can be described as synergistic, antagonistic or additive. This in vitro study evaluated the relationship between the in vitro antioxidant capacity of mixtures and their bioactivity when cardiomyocytes (H9c2) were challenged with H(2)O(2).

RESULTS

A mixture of raspberry and adzuki bean extracts produced a synergistic response and a mixture of broccoli and soybean extracts produced an antagonistic response in chemical-based antioxidant assays. When these extracts were tested in cell cultures, individually and in mixtures, the mixture of raspberry and adzuki bean protected the cardiomyocytes from H(2)O(2)-induced cell damage significantly better than the individual extracts. Conversely, the mixture of broccoli and soybean extracts was less effective in protecting H9c2 cells. The synergistic and antagonistic effects of the mixtures in protecting cell damage were brought about by enhanced or reduced ability in attenuating caspase-3 and matrix metalloproteinase-2 activities elevated by H(2)O(2).

CONCLUSION

Food mixtures with synergistic antioxidant activity and protective property against reactive oxygen species-induced cell death can potentially be incorporated into novel functional foods or beverages with optimum health benefit. The antagonistic effect of food mixtures can be a health concern and thus should be avoided.

Effects of vitamin C supplementation on blood pressure: a meta-analysis of randomized controlled trials

BACKGROUND

In observational studies, increased vitamin C intake, vitamin C supplementation, and higher blood concentrations of vitamin C are associated with lower blood pressure (BP). However, evidence for blood pressure-lowering effects of vitamin C in clinical trials is inconsistent.

OBJECTIVE

The objective was to conduct a systematic review and meta-analysis of clinical trials that examined the effects of vitamin C supplementation on BP.

DESIGN

We searched Medline, EMBASE, and Central databases from 1966 to 2011. Prespecified inclusion criteria were as follows: 1) use of a randomized controlled trial design; 2) trial reported effects on systolic BP (SBP) or diastolic BP (DBP) or both; 3) trial used oral vitamin C and concurrent control groups; and 4) trial had a minimum duration of 2 wk. BP effects were pooled by random-effects models, with trials weighted by inverse variance.

RESULTS

Twenty-nine trials met eligibility criteria for the primary analysis. The median dose was 500 mg/d, the median duration was 8 wk, and trial sizes ranged from 10 to 120 participants. The pooled changes in SBP and DBP were -3.84 mm Hg (95% CI: -5.29, -2.38 mm Hg; P < 0.01) and -1.48 mm Hg (95% CI: -2.86, -0.10 mm Hg; P = 0.04), respectively. In trials in hypertensive participants, corresponding reductions in SBP and DBP were -4.85 mm Hg (P < 0.01) and -1.67 mm Hg (P = 0.17). After the inclusion of 9 trials with imputed BP effects, BP effects were attenuated but remained significant.

CONCLUSIONS

In short-term trials, vitamin C supplementation reduced SBP and DBP. Long-term trials on the effects of vitamin C supplementation on BP and clinical events are needed.

Mitochondrial dynamic remodeling in strenuous exercise-induced muscle and mitochondrial dysfunction: regulatory effects of hydroxytyrosol

Physical exercise is considered to exert a positive effect on health, whereas strenuous or excessive exercise (Exe) causes fatigue and damage to muscle and immune functions. The underlying molecular mechanisms are still unclear. We designed a protocol to mimic Exe and explore the ensuing cellular damage and involvement of mitochondrial dynamics. We found that Exe was prone to decrease endurance capacity and induce damage to renal function and the immune system. Muscle atrophy markers atrogin-1 and MuRF1 mRNA were increased by Exe, accompanied by increased autophagy and mitochondrial fission in skeletal muscle. Exe caused a decrease in PGC-1α and complex I expression; it also activated JNK and Erk1/2 pathways and consequently induced p53, p21, and MnSOD expression in skeletal muscle. The involvement of oxidant-induced autophagy and mitochondrial dysfunction was confirmed in C2C12 myoblasts. Hydroxytyrosol (HT), a natural olive polyphenol, efficiently enhanced endurance capacity and prevented Exe-induced renal and immune system damage. Also, HT treatment inhibited both the Exe-induced increase in autophagy and mitochondrial fission and the decrease in PGC-1α expression. In addition, HT enhanced mitochondrial fusion and mitochondrial complex I and II activities in muscle of Exe rats. These results demonstrate that Exe-induced fatigue and damage to muscle and immune functions may be mediated via the regulation of mitochondrial dynamic remodeling, including the downregulation of mitochondrial biogenesis and upregulation of autophagy. HT supplementation may regulate mitochondrial dynamic remodeling and enhance antioxidant defenses and thus improve exercise capacity under Exe conditions.

Effect of an antioxidant functional food beverage on exercise-induced oxidative stress: a long-term and large-scale clinical intervention study

The efficacy of long-term intake of a novel functional food supplement Funciona™ containing vitamins and juiced fruits was evaluated in order to assess the net effect of physical activity and antioxidant potentials in healthy older adult population. The long-term (2 years) and large-scale (400 older adult subjects) interventional study was based on both moderate-intensity exercise practice and concurrent supplementation. Sustained exercise-induced oxidative stress as reflected in significantly increased blood thiobarbituric acid-reactive substances (TBARS) (+15%), protein carbonyl groups (PC) (+18%) and oxidized glutathione (GSSG) (+112%) concentrations, and leukocyte 8-OHdG contents (23%). Exercise decreased the reduced/oxidized glutathione (GSH/GSSG) molar ratio (-43%) and plasma vitamin C levels (-22%). Supplementation with Funciona™ was significant in preventing oxidative damage to lipid, protein and DNA, and normalizing blood GSSG, GSH/GSSG and vitamin C levels. Thus daily intake of the antioxidant functional beverage counteracts the exercise-induced oxidative stress in free-living older subjects, and might be necessary to restore impaired antioxidant balance due long-term regular exercise.

Association of oxidative stress and paraoxonase status with PROCAM risk score

OBJECTIVES

Oxidative stress and paraoxonase activity play a significant role in the pathogenesis of cardiovascular disease (CVD). The Prospective Cardiovascular Münster (PROCAM) study evaluated the prevalence of CVD risk factors and postulated the prediction of future CVD events. We therefore investigated the association between plasma markers of oxidative stress and paraoxonase status with PROCAM risk score.

DESIGN AND METHODS

Oxidative stress status parameters [lipid peroxidation measured as thiobarbituric acid-reacting substances (TBARS), superoxide anion (O(2)(-)), superoxide dismutase (SOD) activity, total sulphydryl group content] and paraoxonase (PON1) status were assessed in 211 participants. The predicted 10-year risk was calculated according to the PROCAM algorithm.

RESULTS

As expected subjects with high PROCAM risk score (high CVD risk) had significantly higher concentrations of oxidative stress parameters (TBARS and O(2)(-)P<0.001 and P<0.05, respectively). The PON1(192) phenotype distribution among CVD risk groups was not significantly different. Logistic regression analyses revealed significant associations of all the examined oxidative stress status parameters with calculated CVD risk score. The potential of the parameters for CVD risk prediction was tested via multivariate analysis. Only the O(2)(-) level retained a strong association with high CVD risk.

CONCLUSIONS

Our study demonstrated that high PROCAM risk score is associated with increased oxidative stress, indicating for the first time that elevated O(2)(-) is independently associated with high CVD risk.

Therapeutic effect of phytoecdysteroids rich extract from Ajuga iva on alloxan induced diabetic rats liver, kidney and pancreas

In the current study, the effect of Ajuga iva extract on blood glucose, lipid profile, hepatic and renal toxicity and antioxidant enzyme activities in alloxan-induced diabetic rats was investigated. Diabetes was confirmed by measuring the glucoserua concentration 15 days after alloxan administration. Ajuga iva extract was administrated orally 3 weeks after alloxan injection. Our results investigate that Ajuga iva extract supplementation increased the levels of both enzymatic antioxidant (superoxide dismutase, catalase and glutathione peroxidase) and metals antioxidants (iron, copper, magnesium, calcium) and decreased lipid peroxidation level (TBARs). Besides Ajuga iva ameliorated diabetes provoked hepatic and renal toxicity appeared by a lower level in total and direct bilirubin, urea, creatinine, triglyceride (TG), cholesterol and a higher level in HDL-cholesterol. Besides, the activities of phosphatase alkalines (PAL), aspartate and lactate transaminase (AST & ALT) were decreased. The benefices effects of phytoecdysteroids of Ajuga iva confirmed by histological observation in pancreatic tissues. In conclusion, Ajuga iva phytoecdysteroids supplements seem to be beneficial for correcting the hyperglycemia and preventing diabetic complications in liver, pancreas and kidneys.