Oxidative stress and aging. Role of exercise and its influences on antioxidant systems

The beneficial role of exercise in preventing doxorubicin-induced cardiotoxicity

Doxorubicin is a highly effective chemotherapeutic agent widely used to treat a variety of cancers. However, the clinical application of doxorubicin is limited due to its adverse effects on several tissues. One of the most serious side effects of doxorubicin is cardiotoxicity, which results in life-threatening heart damage, leading to reduced cancer treatment success and survival rate. Doxorubicin-induced cardiotoxicity results from cellular toxicity, including increased oxidative stress, apoptosis, and activated proteolytic systems. Exercise training has emerged as a non-pharmacological intervention to prevent cardiotoxicity during and after chemotherapy. Exercise training stimulates numerous physiological adaptations in the heart that promote cardioprotective effects against doxorubicin-induced cardiotoxicity. Understanding the mechanisms responsible for exercise-induced cardioprotection is important to develop therapeutic approaches for cancer patients and survivors. In this report, we review the cardiotoxic effects of doxorubicin and discuss the current understanding of exercise-induced cardioprotection in hearts from doxorubicin-treated animals.

Is It Good to Have a Stiff Aorta with Aging? Causes and Consequences

Aortic stiffness increases with advancing age, more than doubling during the human life span, and is a robust predictor of cardiovascular disease (CVD) clinical events independent of traditional risk factors. The aorta increases in diameter and length to accommodate growing body size and cardiac output in youth, but in middle and older age the aorta continues to remodel to a larger diameter, thinning the pool of permanent elastin fibers, increasing intramural wall stress and resulting in the transfer of load bearing onto stiffer collagen fibers. Whereas aortic stiffening in early middle age may be a compensatory mechanism to normalize intramural wall stress and therefore theoretically "good" early in the life span, the negative clinical consequences of accelerated aortic stiffening beyond middle age far outweigh any earlier physiological benefit. Indeed, aortic stiffness and the loss of the "windkessel effect" with advancing age result in elevated pulsatile pressure and flow in downstream microvasculature that is associated with subclinical damage to high-flow, low-resistance organs such as brain, kidney, retina, and heart. The mechanisms of aortic stiffness include alterations in extracellular matrix proteins (collagen deposition, elastin fragmentation), increased arterial tone (oxidative stress and inflammation-related reduced vasodilators and augmented vasoconstrictors; enhanced sympathetic activity), arterial calcification, vascular smooth muscle cell stiffness, and extracellular matrix glycosaminoglycans. Given the rapidly aging population of the United States, aortic stiffening will likely contribute to substantial CVD burden over the next 2-3 decades unless new therapeutic targets and interventions are identified to prevent the potential avalanche of clinical sequelae related to age-related aortic stiffness.

Endothelial SIRT1 as a Target for the Prevention of Arterial Aging: Promises and Challenges

ABSTRACT

SIRT1, a member of the sirtuin family of longevity regulators, possesses potent activities preventing vascular aging. The expression and function of SIRT1 in endothelial cells are downregulated with age, in turn causing early vascular aging and predisposing various vascular abnormalities. Overexpression of SIRT1 in the vascular endothelium prevents aging-associated endothelial dysfunction and senescence, thus the development of hypertension and atherosclerosis. Numerous efforts have been directed to increase SIRT1 signaling as a potential strategy for different aging-associated diseases. However, the complex mechanisms underlying the regulation of SIRT1 have posed a significant challenge toward the design of specific and effective therapeutics. This review aimed to provide a summary on the regulation and function of SIRT1 in the vascular endothelium and to discuss the different approaches targeting this molecule for the prevention and treatment of age-related cardiovascular and cerebrovascular diseases.

Hyperphosphatemia-Induced Oxidant/Antioxidant Imbalance Impairs Vascular Relaxation and Induces Inflammation and Fibrosis in Old Mice

Aging impairs vascular function, but the mechanisms involved are unknown. The aim of this study was to analyze whether aging-related hyperphosphatemia is implied in this effect by elucidating the role of oxidative stress. C57BL6 mice that were aged 5 months (young) and 24 months (old), receiving a standard (0.6%) or low-phosphate (0.2%) diet, were used. Isolated mesenteric arteries from old mice showed diminished endothelium-dependent vascular relaxation by the down-regulation of NOS3 expression, increased inflammation and increased fibrosis in isolated aortas, compared to those isolated from young mice. In parallel, increased Nox4 expression and reduced Nrf2, Sod2-Mn and Gpx1 were found in the aortas from old mice, resulting in oxidant/antioxidant imbalance. The low-phosphate diet improved vascular function and oxidant/antioxidant balance in old mice. Mechanisms were analyzed in endothelial (EC) and vascular smooth muscle cells (SMCs) treated with the phosphate donor ß-glycerophosphate (BGP). In EC, BGP increased Nox4 expression and ROS production, which reduced NOS3 expression via NFκB. BGP also increased inflammation in EC. In SMC, BGP increased Collagen I and fibronectin expression by priming ROS production and NFκB activity. In conclusion, hyperphosphatemia reduced endothelium-dependent vascular relaxation and increased inflammation and vascular fibrosis through an impairment of oxidant/antioxidant balance in old mice. A low-phosphate diet achieved improvements in the vascular function in old mice.

Effect of Oxidative Stress on Diaphragm Dysfunction and Exercise Intervention in Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) can cause extrapulmonary injury such as diaphragm dysfunction. Oxidative stress is one of the main factors causing diaphragm dysfunction in COPD. Exercise plays a positive role in the prevention and treatment of diaphragm dysfunction in COPD, and the changes in diaphragm structure and function induced by exercise are closely related to the regulation of oxidative stress. Therefore, on the basis of the review of oxidative stress and the changes in diaphragm structure and function in COPD, this article analyzed the effects of exercise on oxidative stress and diaphragm dysfunction in COPD and explored the possible mechanism by which exercise improves oxidative stress. Studies have found that diaphragm dysfunction in COPD includes the decline of muscle strength, endurance, and activity. Oxidative stress mainly affects the structure and function of the diaphragm in COPD through protein oxidation, protease activation and calcium sensitivity reduction. The effects of exercise on oxidative stress level and diaphragm dysfunction may differ depending on the intensity, duration, and style of exercise. The mechanism of exercise on oxidative stress in the diaphragm of COPD may include improving antioxidant capacity, reducing oxidase activity and improving mitochondrial function.

Physical Activity and Redox Balance in the Elderly: Signal Transduction Mechanisms

Reactive Oxygen Species (ROS) are molecules naturally produced by cells. If their levels are too high, the cellular antioxidant machinery intervenes to bring back their quantity to physiological conditions. Since aging often induces malfunctioning in this machinery, ROS are considered an effective cause of age-associated diseases. Exercise stimulates ROS production on one side, and the antioxidant systems on the other side. The effects of exercise on oxidative stress markers have been shown in blood, vascular tissue, brain, cardiac and skeletal muscle, both in young and aged people. However, the intensity and volume of exercise and the individual subject characteristics are important to envisage future strategies to adequately personalize the balance of the oxidant/antioxidant environment. Here, we reviewed the literature that deals with the effects of physical activity on redox balance in young and aged people, with insights into the molecular mechanisms involved. Although many molecular pathways are involved, we are still far from a comprehensive view of the mechanisms that stand behind the effects of physical activity during aging. Although we believe that future precision medicine will be able to transform exercise administration from wellness to targeted prevention, as yet we admit that the topic is still in its infancy.

Blood total antioxidant status is associated with cortical glucose uptake and factors related to accelerated aging

Identifying cerebral vulnerability in late life is of paramount importance to prevent pathological trajectories of aging before the onset of symptoms. Considerable evidence suggests that impaired antioxidant mechanisms are a fingerprint of aging-related conditions, but there is a lack of human research linking total antioxidant capacity (TAC) measured in peripheral blood to in vivo brain changes and other factors featuring accelerated aging. To address this issue, we have assessed in cognitively normal elderly subjects (N = 100) correlations between serum TAC, using the oxygen radical absorbance capacity assay, surface-based cortical thickness, surface-based 18F-fluorodeoxyglucose positron emission tomography cortical uptake, and different factors associated with accelerated aging [i.e., serum homocysteine (HCY), self-reported memory problems, and self-reported patterns of physical activity]. While no relationship was observed between serum TAC and variations in cortical thickness, decreased TAC level was significantly associated with lower FDG uptake in temporal lobes bilaterally. Remarkably, decreased TAC level was linked to increased HCY concentrations, more subjective memory complaints, and lower frequency of physical activity. Overall, our results suggest that decreased serum TAC level may be helpful to detect vulnerable trajectories of aging.

Fatty Acid Profile and Antioxidant Status Fingerprint in Sarcopenic Elderly Patients: Role of Diet and Exercise

Plasma fatty acids (FAs) and oxidant status contribute to the etiology of sarcopenia in the elderly concurring to age-related muscle loss and elderly frailty through several mechanisms including changes in FA composition within the sarcolemma, promotion of chronic low-grade inflammation, and insulin resistance. The aim of this study was to determine the FA profile and pro-antioxidant status in sarcopenic frail elderly patients enrolled in a nutritional and physical activity program and to evaluate their correlation with clinical markers. Moreover, the possible changes, produced after a short-term clinical protocol, were evaluated. Plasma and erythrocyte FA composition and pro-antioxidant status were analyzed in sarcopenic elderly subjects recruited for the randomized clinical study and treated with a placebo or dietary supplement, a personalized diet, and standardized physical activity. Subjects were tested before and after 30 days of treatment. Pearson correlations between biochemical parameters and patients’ characteristics at recruitment indicate interesting features of sarcopenic status such as negative correlation among the plasma FA profile, age, and physical characteristics. Physical activity and dietetic program alone for 30 days induced a decrease of saturated FA concentration with a significant increase of dihomo-gamma-linolenic acid. Supplementation plus physical activity induced a significant decrease of linoleic acid, omega-6 polyunsaturated FAs, and an increase of stearic and oleic acid concentration. Moreover, glutathione reductase activity, which is an indicator of antioxidant status, significantly increased in erythrocytes. Changes over time between groups indicate significant differences for saturated FAs, which suggest that the amino acid supplementation restores FA levels that are consumed during physical activity. A relationship between FA and clinical/metabolic status revealed unique correlations and a specific metabolic and lipidomic fingerprint in sarcopenic elderly. The results indicate the positive beneficial role of supplementation and physical activity on plasma FA status and the antioxidant system as a co-adjuvant approach in sarcopenic, frail, elderly patients.

Combined exercise training improves blood pressure and antioxidant capacity in elderly individuals with hypertension

Background/objective

Although regular exercise plays a role in achieving healthy aging, a specific mode of exercise may be required for elderly individuals with hypertension (HT). Therefore, this study aimed to assess the effects of combined endurance and strength training (CBT) on blood pressure (BP) and antioxidant capacity in elderly individuals with HT.

Methods

In a single-blinded, randomized controlled trial, 54 older men and women aged 67 ± 5.8 years completed endurance training (ET, n = 13), strength training (ST, n = 13), combined endurance and strength training (CBT, n = 16) or served as controls (CON, n = 12). The intervention was a supervised exercise training (1-h sessions, three per week for 12 weeks), followed by a self-supervised exercise training for 12 weeks. Measurements of BP, glutathione peroxidase (GPx), total nitrite/nitrate (NOx-), malondialdehyde (MDA), and high-sensitive C-reactive protein (hs-CRP) were obtained before and after the supervised and the self-supervised periods.

Results

After the supervised period, systolic BP (SBP) decreased by 7.9% in the ET (p < 0.05) and 8.2% in the CBT (p < 0.01); GPx activity increased by 41.3% in the ET (p < 0.01), 19.1% in the ST (p < 0.05), and 49.2% in the CBT (p < 0.01); NOx-concentrations increased by 66.2% in the ET and 71.9% in the CBT (both p < 0.01), MDA concentrations decreased by 65.1% in the ST (p < 0.05) and 61% in the CBT (p < 0.01); hs-CRP concentrations decreased by 49.2% in only the CBT (p < 0.05). After the self-supervised period, SBP decreases by 7.5% in only the CBT (p < 0.01); NOx-concentrations increased by 68.5% in the ET and 92.4% in the CBT (both p < 0.01). However, there was no significant difference in SBP, GPx activity, NOx-, MDA and hs-CRP concentrations between the training groups.

Conclusion

The hypotensive and antioxidant effects of the CBT seem to be similar to the ET after the supervised training period. However, after the self-supervised training period, the CBT program might affect better due to greater exercise adherence and attendance in elderly individuals with HT.

The Effects of Swimming Training in Cold Water on Antioxidant Enzyme Activity and Lipid Peroxidation in Erythrocytes of Male and Female Aged Rats

The aim of this study was to verify whether eight-week-long swimming exercise training would evaluate the level of selected indicators of the pro-oxidant/antioxidant status in response to cold water in comparison with swimming under thermoneutral conditions in sedentary male and female elderly rats. The exercise-trained groups swam four min/day and five days a week during eight weeks of housing. Exercise was performed by swimming in glass tanks containing tap water maintained according to group at 5 °C and 36 °C. At the end of treatment (48 h after the last session), all rats were anaesthetized. The level of chosen biomarkers of oxidative stress and antioxidant enzyme activity was determined in the red blood cells and plasma. The results of study show that female rats seem to be better adapted to changing thermal conditions of the environment, developing not only morphological, but also antioxidant, defense mechanisms, mainly in the form of increased erythrocyte superoxide dismutase (SOD) activity and glutathione (GSH) concentration to restore the pro-oxidant/oxidant balance of the organism. Significantly higher concentrations of GSH were observed in the female rats of the group swimming in cold water (by 15.4% compared to the control group and by 20.5% in relation to the group of female rats swimming at 36 °C). In the group exposed to swimming training exercise in cold water, a significantly higher activity of SOD1 (by 13.4%) was found compared to the control group. On the other hand, the organs of ageing male rats show a reduced capacity to increase the metabolic response to low temperatures compared to female ones. In addition, it was demonstrated that cold exposure leads to an increase in lipid peroxidation in tissues. On the other hand, the repeated exposure to low levels of oxidative stress may result in some adaptive changes in organisms that help them to resist stress-induced damage.

Overuse injuries in sport: a comprehensive overview

BACKGROUND

The absence of a single, identifiable traumatic cause has been traditionally used as a definition for a causative factor of overuse injury. Excessive loading, insufficient recovery, and underpreparedness can increase injury risk by exposing athletes to relatively large changes in load. The musculoskeletal system, if subjected to excessive stress, can suffer from various types of overuse injuries which may affect the bone, muscles, tendons, and ligaments.

METHODS

We performed a search (up to March 2018) in the PubMed and Scopus electronic databases to identify the available scientific articles about the pathophysiology and the incidence of overuse sport injuries. For the purposes of our review, we used several combinations of the following keywords: overuse, injury, tendon, tendinopathy, stress fracture, stress reaction, and juvenile osteochondritis dissecans.

RESULTS

Overuse tendinopathy induces in the tendon pain and swelling with associated decreased tolerance to exercise and various types of tendon degeneration. Poor training technique and a variety of risk factors may predispose athletes to stress reactions that may be interpreted as possible precursors of stress fractures. A frequent cause of pain in adolescents is juvenile osteochondritis dissecans (JOCD), which is characterized by delamination and localized necrosis of the subchondral bone, with or without the involvement of articular cartilage. The purpose of this compressive review is to give an overview of overuse injuries in sport by describing the theoretical foundations of these conditions that may predispose to the development of tendinopathy, stress fractures, stress reactions, and juvenile osteochondritis dissecans and the implication that these pathologies may have in their management.

CONCLUSIONS

Further research is required to improve our knowledge on tendon and bone healing, enabling specific treatment strategies to be developed for the management of overuse injuries.

Mechanisms of Dysfunction in the Aging Vasculature and Role in Age-Related Disease

Advancing age promotes cardiovascular disease (CVD), the leading cause of death in the United States and many developed nations. Two major age-related arterial phenotypes, large elastic artery stiffening and endothelial dysfunction, are independent predictors of future CVD diagnosis and likely are responsible for the development of CVD in older adults. Not limited to traditional CVD, these age-related changes in the vasculature also contribute to other age-related diseases that influence mammalian health span and potential life span. This review explores mechanisms that influence age-related large elastic artery stiffening and endothelial dysfunction at the tissue level via inflammation and oxidative stress and at the cellular level via Klotho and energy-sensing pathways (AMPK [AMP-activated protein kinase], SIRT [sirtuins], and mTOR [mammalian target of rapamycin]). We also discuss how long-term calorie restriction-a health span- and life span-extending intervention-can prevent many of these age-related vascular phenotypes through the prevention of deleterious alterations in these mechanisms. Lastly, we discuss emerging novel mechanisms of vascular aging, including senescence and genomic instability within cells of the vasculature. As the population of older adults steadily expands, elucidating the cellular and molecular mechanisms of vascular dysfunction with age is critical to better direct appropriate and measured strategies that use pharmacological and lifestyle interventions to reduce risk of CVD within this population.

Oxidative stress: role of physical exercise and antioxidant nutraceuticals in adulthood and aging

Physical exercise is considered to be one of the beneficial factors of a proper lifestyle and is nowadays seen as an indispensable element for good health, able to lower the risk of disorders of the cardiovascular, endocrine and osteomuscular apparatus, immune system diseases and the onset of potential neoplasms. A moderate and programmed physical exercise has often been reported to be therapeutic both in the adulthood and in aging, since capable to promote fitness. Regular exercise alleviates the negative effects caused by free radicals and offers many health benefits, including reduced risk of all-cause mortality, sarcopenia in the skeletal muscle, chronic disease, and premature death in elderly people. However, physical performance is also known to induce oxidative stress, inflammation, and muscle fatigue. Many efforts have been carried out to identify micronutrients and natural compounds, also known as nutraceuticals, able to prevent or attenuate the exercise-induced oxidative stress and inflammation. The aim of this review is to discuss the benefits deriving from a constant physical activity and by the intake of antioxidant compounds to protect the body from oxidative stress. The attention will be focused mainly on three natural antioxidants, which are quercetin, resveratrol and curcumin. Their properties and activity will be described, as well as their benefits on physical activity and on aging, which is expected to increase through the years and can get favorable benefits from a constant exercise activity.

Reactive oxygen species damage drives cardiac and mitochondrial dysfunction following acute nano-titanium dioxide inhalation exposure

Nanotechnology offers innovation in products from cosmetics to drug delivery, leading to increased engineered nanomaterial (ENM) exposure. Unfortunately, health impacts of ENM are not fully realized. Titanium dioxide (TiO2) is among the most widely produced ENM due to its use in numerous applications. Extrapulmonary effects following pulmonary exposure have been identified and may involve reactive oxygen species (ROS). The goal of this study was to determine the extent of ROS involvement on cardiac function and the mitochondrion following nano-TiO2 exposure. To address this question, we utilized a transgenic mouse model with overexpression of a novel mitochondrially-targeted antioxidant enzyme (phospholipid hydroperoxide glutathione peroxidase; mPHGPx) which provides protection against oxidative stress to lipid membranes. MPHGPx mice and littermate controls were exposed to nano-TiO2 aerosols (Evonik, P25) to provide a calculated pulmonary deposition of 11 µg/mouse. Twenty-four hours following exposure, we observed diastolic dysfunction as evidenced by E/A ratios greater than 2 and increased radial strain during diastole in wild-type mice (p < 0.05 for both), indicative of restrictive filling. Overexpression of mPHGPx mitigated the contractile deficits resulting from nano-TiO2 exposure. To investigate the cellular mechanisms associated with the observed cardiac dysfunction, we focused our attention on the mitochondrion. We observed a significant increase in ROS production (p < 0.05) and decreased mitochondrial respiratory function (p < 0.05) following nano-TiO2 exposure which were attenuated in mPHGPx transgenic mice. In summary, nano-TiO2 inhalation exposure is associated with cardiac diastolic dysfunction and mitochondrial functional alterations, which can be mitigated by the overexpression of mPHGPx, suggesting ROS contribution in the development of contractile and bioenergetic dysfunction.

Epigenetic Regulation of Vascular Aging and Age-Related Vascular Diseases

Vascular aging refers to the structural and functional defects that occur in the aorta during the aging process and is characterized by increased vascular cell senescence, vascular dyshomeostasis, and vascular remodeling. Vascular aging is a major risk factor for vascular diseases. However, the current understanding of the biological process of vascular aging and age-related diseases is insufficient. Epigenetic regulation can influence gene expression independently of the gene sequence and mainly includes DNA methylation, histone modifications, and RNA-based gene regulation. Epigenetic regulation plays important roles in many physiological and pathophysiological processes and may explain some gaps in our knowledge regarding the interaction between genes and diseases. In this review, we summarize recent advances in the understanding of the epigenetic regulation of vascular aging and age-related diseases in terms of vascular cell senescence, vascular dyshomeostasis, and vascular remodeling. Moreover, the possibility of targeting epigenetic regulation to delay vascular aging and treat age-related vascular diseases is also discussed.

Widening and Rotation of Carotid Artery with Age: Geometric Approach

BACKGROUND

The anatomy and geometry of the carotid artery may play an important role in the pathogenesis of internal carotid artery (ICA) stenosis, but the exact nature of this role remains elusive. To clarify this issue, we sought to investigate age-related changes in the anatomy and geometry of the carotid artery in a Korean population.

MATERIALS AND METHODS

We conducted a retrospective study of 300 subjects who underwent carotid contrast-enhanced magnetic resonance angiography at our clinic between 2014 and 2016. The subjects were divided into 7 groups according to age. The carotid arteries were segmented using semiautomated methods to obtain various measurements of carotid anatomy and geometry, as suggested by Thomas et al. The various age groups were compared for different parameters, including ICA angle, bifurcation angle, and vessel volume and diameter.

RESULTS

Analysis of variance showed that with an increase in age, there were significant increases in vessel volume and diameter of the common carotid artery and ICA as well as the carotid bifurcation (P = .000). Significant age-related increase was also noted in the ICA angle and bifurcation angle (P = .000). The anatomical position of the ICA in subjects aged over 60 years was significantly higher than that in subjects below 40 years (12.5% versus .03%, P < .0001).

CONCLUSIONS

Age-related increases were noted in vessel volume and diameter of the carotid artery and ICA as well as the bifurcation angle. The widening and rotation of the carotid artery increased with age.

The interaction effects of resistance training and sustanon abuse on liver antioxidant activities and serum enzymes in male rats

BACKGROUND

Anabolic-androgenic steroids (AAS) are synthetic drugs derived from testosterone, the uncontrolled usage of which may lead to serious side effects. Previous studies have shown that resistance training (RT) is the main exercise modality practiced by AAS abusers. Thus, this work was carried out to evaluate the hepatotoxic effects of sustanon (Su) as an example of AAS in trained male rats.

METHODS

Rats were divided into sedentary/non-Su, sedentary/Su, RT/non-Su, and RT/Su. Su-administration groups received Su 10 mg/kg intramuscularly once a week for 8 weeks. In the 8-week RT, the rats climbed a vertical ladder 3 days/week.

RESULTS

After Su administration, the mean values of serum parameters related to hepatic function were within normal ranges. Superoxide dismutase, glutathione peroxidase, and glutathione reductase activities were higher (P < 0.05) in the liver of Su-treated rats. Chronic exercise alone did not change any of the above parameters.

CONCLUSIONS

The present findings suggest that the 8-week injection of Su, either with or without concurrent RT upregulation of enzymatic antioxidant activities and RT, did not attenuate the increase of enzymatic activities due to the Su administration. Furthermore, Su abuse in this dose did not make any severe liver damage.

Maternal exercise during pregnancy reduces the risk of preterm birth through the mediating role of placenta

OBJECTIVE

The extent of research on maternal exercise during pregnancy and the risk of preterm birth (PTB) have grown substantially, but conclusions still remained controversial. Thus, this study aims to examine the relationship of maternal exercise during pregnancy and PTB and explore whether placenta mediates their relationship.

STUDY DESIGN

We investigated 849 pregnant women delivering PTB newborns (cases) and 1306 delivering full-term appropriate for gestational age newborns (controls) in this case-control study. Information concerning maternal exercise during pregnancy, sociodemographics and obstetric characteristics were collected at Women and Children's Hospitals of Shenzhen and Foshan in Guangdong, China. A series of logistic and linear regressions were used to examine the relationships of maternal exercise during pregnancy, placenta, and PTB.

RESULTS

After adjusting for the potential confounders, maternal exercise frequency and duration during pregnancy were negatively associated with PTB. Moreover, compared with mother taking no exercise during pregnancy, those taking exercise lowered the risk of PTB except those taking low/medium frequency and short duration exercise, and their adjusted ORs ranged from 0.43 to 0.65. Furthermore, mediation analysis illustrated that placental weight partially mediated 65.20% of the effects of maternal exercise frequency on PTB, as well as 41.98% of the association between maternal exercise duration and PTB.

CONCLUSIONS

Maternal exercise during pregnancy is beneficial for lowering the risk of PTB, especially when taking appropriate and enough exercise. Placenta weight may partially mediate the association between maternal exercise during pregnancy and PTB.

Arterial ageing: from endothelial dysfunction to vascular calcification

Complex structural and functional changes occur in the arterial system with advancing age. The aged artery is characterized by changes in microRNA expression patterns, autophagy, smooth muscle cell migration and proliferation, and arterial calcification with progressively increased mechanical vessel rigidity and stiffness. With age the vascular smooth muscle cells modify their phenotype from contractile to 'synthetic' determining the development of intimal thickening as early as the second decade of life as an adaptive response to forces acting on the arterial wall. The increased permeability observed in intimal thickening could represent the substrate on which low-level atherosclerotic stimuli can promote the development of advanced atherosclerotic lesions. In elderly patients the atherosclerotic plaques tend to be larger with increased vascular stenosis. In these plaques there is a progressive accumulation of both lipids and collagen and a decrease of inflammation. Similarly the plaques from elderly patients show more calcification as compared with those from younger patients. The coronary artery calcium score is a well-established marker of adverse cardiovascular outcomes. The presence of diffuse calcification in a severely stenotic segment probably induces changes in mechanical properties and shear stress of the arterial wall favouring the rupture of a vulnerable lesion in a less stenotic adjacent segment. Oxidative stress and inflammation appear to be the two primary pathological mechanisms of ageing-related endothelial dysfunction even in the absence of clinical disease. Arterial ageing is no longer considered an inexorable process. Only a better understanding of the link between ageing and vascular dysfunction can lead to significant advances in both preventative and therapeutic treatments with the aim that in the future vascular ageing may be halted or even reversed.

Age-related alterations in the sarcolemmal environment are attenuated by lifelong caloric restriction and voluntary exercise

Age-related loss of skeletal muscle mass and function, referred to as sarcopenia, is mitigated by lifelong calorie restriction as well as exercise. In aged skeletal muscle fibers there is compromised integrity of the cell membrane that may contribute to sarcopenia. The purpose of this study was to determine if lifelong mild (8%) caloric restriction (CR) and lifelong CR+voluntary wheel running (WR) could ameliorate disruption of membrane scaffolding and signaling proteins during the aging process, thus maintaining a favorable, healthy membrane environment in plantaris muscle fibers. Fischer-344 rats were divided into four groups: 24-month old adults fed ad libitum (OAL); 24-month old on 8% caloric restriction (OCR); 24month old 8% caloric restriction+wheel running (OCRWR); and 6-month old sedentary adults fed ad libitum (YAL) were used to determine age-related changes. Aging resulted in discontinuous membrane expression of dystrophin glycoprotein complex (DGC) proteins: dystrophin and α-syntrophin. Older muscle also displayed decreased content of neuronal nitric oxide synthase (nNOS), a key DGC signaling protein. In contrast, OCR and OCRWR provided significant protection against age-related DGC disruption. In conjunction with the age-related decline in membrane DGC patency, key membrane repair proteins (MG53, dysferlin, annexin A6, and annexin A2) were significantly increased in the OAL plantaris. However, lifelong CR and CRWR interventions were effective at maintaining membrane repair proteins near YAL levels of. OAL fibers also displayed reduced protein content of NADPH oxidase isoform 2 (Nox2) subunits (p67phox and p47phox), consistent with a perturbed sarcolemmal environment. Loss of Nox2 subunits was prevented by lifelong CR and CRWR. Our results are therefore consistent with the hypothesis that lifelong CR and WR are effective countermeasures against age-related alterations in the myofiber membrane environment.

Voluntary locomotor activity mitigates oxidative damage associated with isolation stress in the prairie vole (Microtus ochrogaster)

Organismal performance directly depends on an individual's ability to cope with a wide array of physiological challenges. For social animals, social isolation is a stressor that has been shown to increase oxidative stress. Another physiological challenge, routine locomotor activity, has been found to decrease oxidative stress levels. Because we currently do not have a good understanding of how diverse physiological systems like stress and locomotion interact to affect oxidative balance, we studied this interaction in the prairie vole (Microtus ochrogaster). Voles were either pair housed or isolated and within the isolation group, voles either had access to a moving wheel or a stationary wheel. We found that chronic periodic isolation caused increased levels of oxidative stress. However, within the vole group that was able to run voluntarily, longer durations of locomotor activity were associated with less oxidative stress. Our work suggests that individuals who demonstrate increased locomotor activity may be better able to cope with the social stressor of isolation.

Hypertension and aging

Hypertension is a highly prevalent condition with numerous health risks, and the incidence of hypertension is greatest among older adults. Traditional discussions of hypertension have largely focused on the risks for cardiovascular disease and associated events. However, there are a number of collateral effects, including risks for dementia, physical disability, and falls/fractures which are increasingly garnering attention in the hypertension literature. Several key mechanisms--including inflammation, oxidative stress, and endothelial dysfunction--are common to biologic aging and hypertension development and appear to have key mechanistic roles in the development of the cardiovascular and collateral risks of late-life hypertension. The objective of the present review is to highlight the multi-dimensional risks of hypertension among older adults and discuss potential strategies for treatment and future areas of research for improving overall care for older adults with hypertension.

Exercise Modulates Oxidative Stress and Inflammation in Aging and Cardiovascular Diseases

Despite the wealth of epidemiological and experimental studies indicating the protective role of regular physical activity/exercise training against the sequels of aging and cardiovascular diseases, the molecular transducers of exercise/physical activity benefits are not fully identified but should be further investigated in more integrative and innovative approaches, as they bear the potential for transformative discoveries of novel therapeutic targets. As aging and cardiovascular diseases are associated with a chronic state of oxidative stress and inflammation mediated via complex and interconnected pathways, we will focus in this review on the antioxidant and anti-inflammatory actions of exercise, mainly exerted on adipose tissue, skeletal muscles, immune system, and cardiovascular system by modulating anti-inflammatory/proinflammatory cytokines profile, redox-sensitive transcription factors such as nuclear factor kappa B, activator protein-1, and peroxisome proliferator-activated receptor gamma coactivator 1-alpha, antioxidant and prooxidant enzymes, and repair proteins such as heat shock proteins, proteasome complex, oxoguanine DNA glycosylase, uracil DNA glycosylase, and telomerase. It is important to note that the effects of exercise vary depending on the type, intensity, frequency, and duration of exercise as well as on the individual's characteristics; therefore, the development of personalized exercise programs is essential.

Regional Heterogeneity of Cerebral Microvessels and Brain Susceptibility to Oxidative Stress

The hippocampus is one of the earliest and most affected regions in Alzheimer's disease (AD), followed by the cortex while the cerebellum is largely spared. Importantly, endothelial dysfunction is a common feature of cerebral blood vessels in AD. In this study, we sought to determine if regional heterogeneity of cerebral microvessels might help explain the susceptibility of the hippocampus and cortex as compared to the cerebellum. We isolated microvessels from wild type mice from the cerebellum, cortex, and hippocampus to characterize their vascular phenotype. Superoxide anion was significantly higher in microvessels isolated from the cortex and hippocampus as compared to the cerebellum. Importantly, protein levels of NADPH oxidase (NOX)-2 and NOX-4 were significantly higher in the cortical and hippocampal microvessels as compared to microvessels from the cerebellum. In addition, expression of manganese superoxide dismutase protein was significantly lower in microvessels from the cortex and hippocampus as compared to cerebellum while other antioxidant enzymes were unchanged. There was no difference in eNOS protein expression between the microvessels of the three brain regions; however, bioavailability of tetrahydrobiopterin (BH4), an essential cofactor for eNOS activity, was significantly reduced in microvessels from the hippocampus and cortex as compared to the cerebellum. Higher levels of superoxide and reduced tetrahydrobiopterin bioavailability may help explain the vulnerability of the hippocampus and cortical microvessels to oxidative stress and development of endothelial dysfunction.

Type 5 adenylyl cyclase disruption leads to enhanced exercise performance

The most important physiological mechanism mediating enhanced exercise performance is increased sympathetic, beta adrenergic receptor (β-AR), and adenylyl cyclase (AC) activity. This is the first report of decreased AC activity mediating increased exercise performance. We demonstrated that AC5 disruption, that is, knock out (KO) mice, a longevity model, increases exercise performance. Importantly for its relation to longevity, exercise was also improved in old AC5 KO. The mechanism resided in skeletal muscle rather than in the heart, as confirmed by cardiac- and skeletal muscle-specific AC5 KO's, where exercise performance was no longer improved by the cardiac-specific AC5 KO, but was by the skeletal muscle-specific AC5 KO, and there was no difference in cardiac output during exercise in AC5 KO vs. WT. Mitochondrial biogenesis was a major mechanism mediating the enhanced exercise. SIRT1, FoxO3a, MEK, and the anti-oxidant, MnSOD were upregulated in AC5 KO mice. The improved exercise in the AC5 KO was blocked with either a SIRT1 inhibitor, MEK inhibitor, or by mating the AC5 KO with MnSOD hetero KO mice, confirming the role of SIRT1, MEK, and oxidative stress mechanisms. The Caenorhabditis elegans worm AC5 ortholog, acy-3 by RNAi, also improved fitness, mitochondrial function, antioxidant defense, and lifespan, attesting to the evolutionary conservation of this pathway. Thus, decreasing sympathetic signaling through loss of AC5 is not only a mechanism to improve exercise performance, but is also a mechanism to improve healthful aging, as exercise also protects against diabetes, obesity, and cardiovascular disease, which all limit healthful aging.

Cellular and molecular biology of aging endothelial cells

Cardiovascular disease (CVD) is the leading cause of death in the United States and aging is a major risk factor for CVD development. One of the major age-related arterial phenotypes thought to be responsible for the development of CVD in older adults is endothelial dysfunction. Endothelial function is modulated by traditional CVD risk factors in young adults, but advancing age is independently associated with the development of vascular endothelial dysfunction. This endothelial dysfunction results from a reduction in nitric oxide bioavailability downstream of endothelial oxidative stress and inflammation that can be further modulated by traditional CVD risk factors in older adults. Greater endothelial oxidative stress with aging is a result of augmented production from the intracellular enzymes NADPH oxidase and uncoupled eNOS, as well as from mitochondrial respiration in the absence of appropriate increases in antioxidant defenses as regulated by relevant transcription factors, such as FOXO. Interestingly, it appears that NFkB, a critical inflammatory transcription factor, is sensitive to this age-related endothelial redox change and its activation induces transcription of pro-inflammatory cytokines that can further suppress endothelial function, thus creating a vicious feed-forward cycle. This review will discuss the two macro-mechanistic processes, oxidative stress and inflammation, that contribute to endothelial dysfunction with advancing age as well as the cellular and molecular events that lead to the vicious cycle of inflammation and oxidative stress in the aged endothelium. Other potential mediators of this pro-inflammatory endothelial phenotype are increases in immune or senescent cells in the vasculature. Of note, genomic instability, telomere dysfunction or DNA damage has been shown to trigger cell senescence via the p53/p21 pathway and result in increased inflammatory signaling in arteries from older adults. This review will discuss the current state of knowledge regarding the emerging concepts of senescence and genomic instability as mechanisms underlying oxidative stress and inflammation in the aged endothelium. Lastly, energy sensitive/stress resistance pathways (SIRT-1, AMPK, mTOR) are altered in endothelial cells and/or arteries with aging and these pathways may modulate endothelial function via key oxidative stress and inflammation-related transcription factors. This review will also discuss what is known about the role of "energy sensing" longevity pathways in modulating endothelial function with advancing age. With the growing population of older adults, elucidating the cellular and molecular mechanisms of endothelial dysfunction with age is critical to establishing appropriate and measured strategies to utilize pharmacological and lifestyle interventions aimed at alleviating CVD risk. This article is part of a Special Issue entitled "SI: CV Aging".

Chronic aerobic swimming exercise promotes functional and morphological changes in rat ileum

In the present study, we evaluated the influence of chronic swimming aerobic exercise on the contractile reactivity, lipid peroxidation and tissue morphology of small intestine from rats. We showed that, accordingly to the time of exercise, the rat ileum has its contractile reactivity reduced, in addition to the increased lipid peroxidation followed by its reestablishment to basal levels, as well as the augmented longitudinal smooth muscle layer thickness together with the reduced circular thickness.

Several studies have reported the gastrointestinal (GI) effects promoted by the physical exercise. Thus, we aimed to evaluate the influence of swimming exercise on the contractile reactivity, lipid peroxidation and morphology of rat ileum. Wistar rats were divided into sedentary (SED) and groups exercised for two (EX2), four (EX4), six (EX6) or eight (EX8) weeks, 5 days/week. Animals were killed; the ileum was removed and suspended in organ baths where the isotonic contractions were recorded. Lipid peroxidation was evaluated by MDA (malondialdehyde) measurement with TBARS (thiobarbituric acid reactive substances) assay and morphology by histological staining. Cumulative concentration-response curves to KCl were attenuated, as the E_max values were changed from 100% (SED) to 63.1±3.9 (EX2), 48.8±3.8 (EX4), 19.4±1.8 (EX6) and 59.4±2.8% (EX8). Similarly, cumulative concentration-response curves to carbamylcholine hydrochloride (CCh) were attenuated, as the E_max values were changed from 100% (SED) to 74.1±5.4 (EX2), 75.9±5.2 (EX4) and 62.9±4.6 (EX6), but not in the EX8 (89.7±3.4%). However, CCh potency was increased in this latter, as the EC₅₀ was altered from 1.0±0.1×10⁻⁶ (SED) to 2.1±0.4×10⁻⁷ (EX8). MDA concentration was altered only in EX4 (44.3±4.4) compared with SED (20.6±3.6 μmol/l). Circular layer was reduced in SED when compared with the exercised groups. Conversely, longitudinal layer was increased. In conclusion, chronic swimming exercise reduces the ileum contraction, equilibrates the oxidative damage and promotes changes in tissue size to establish an adaptation to the exercise.

Comparative study of enzymatic antioxidants in muscle of elasmobranch and teleost fishes

Exercise may cause an imbalance between pro-oxidants and antioxidants. In skeletal muscle, oxygen flow can increase considerably during vigorous exercise. The antioxidant system in athletes contributes to neutralize the concomitant rise in reactive oxygen species (ROS) production. The objective of this study was to compare the antioxidant system in muscle of three species of elasmobranchs and teleosts, considering differences in swimming capacity among species within each group and evolutionary differences between the two groups. Muscle samples were collected from elasmobranchs (Isurus oxyrinchus, Prionace glauca, Mustelus henlei) and teleosts (Totoaba macdonaldi, Kajikia audax and Coryphaena hippurus) in the coast of the Baja California peninsula, Mexico. The enzymatic activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) was determined by spectrophotometry. The activity of the antioxidant enzymes CAT, GPx and GST was higher in elasmobranchs, as a group, than in teleosts. In fish species with high swimming capacities, P. glauca, K. audax and C. hippurus, antioxidant enzyme activity was higher in comparison with species with lower swimming capacities, M. henlei and T. macdonaldi. It is possible that antioxidant enzymes, particularly SOD, GPx and GST, contribute to avoidance of oxidative damage in teleost and elasmobranch species with higher swimming capacities. The antioxidant enzyme activities in fish appear to depend mainly on their swimming capacity and life style rather than the evolutionary group (elasmobranchs, teleosts).

Muscle wasting in rheumatoid arthritis: The role of oxidative stress

Rheumatoid arthritis (RA), the commonest inflammatory arthritis, is a debilitating disease leading to functional and social disability. In addition to the joints, RA affects several other tissues of the body including the muscle. RA patients have significantly less muscle mass compared to the general population. Several theories have been proposed to explain this. High grade inflammation, a central component in the pathophysiology of the disease, has long been proposed as the key driver of muscle wasting. More recent findings however, indicate that inflammation on its own cannot fully explain the high prevalence of muscle wasting in RA. Thus, the contribution of other potential confounders, such as nutrition and physical activity, has also been studied. Results indicate that they play a significant role in muscle wasting in RA, but again neither of these factors seems to be able to fully explain the condition. Oxidative stress is one of the major mechanisms thought to contribute to the development and progression of RA but its potential contribution to muscle wasting in these patients has received limited attention. Oxidative stress has been shown to promote muscle wasting in healthy populations and people with several chronic conditions. Moreover, all of the aforementioned potential contributors to muscle wasting in RA (i.e., inflammation, nutrition, and physical activity) may promote pro- or anti-oxidative mechanisms. This review aims to highlight the importance of oxidative stress as a driving mechanism for muscle wasting in RA and discusses potential interventions that may promote muscle regeneration via reduction in oxidative stress.

Contribution of receptor for advanced glycation end products to vasculature-protecting effects of exercise training in aged rats

The aim of present work was to investigate the underlying mechanism of vasculature-protecting effects of exercise training in aged rats. Experiment 1: aged rats were given moderate-intensity exercise for 12 weeks. Exercise training suppressed advanced glycation evidenced by reduced activity of aldose reductase, increased activity of glyoxalase 1, reduced levels of methylglyoxal and N(ε)-(carboxymethyl) lysine, and decreased expression of receptor for advanced glycation end products (RAGE) in aged aortas. Experiment 2: aged rats were given moderate-intensity exercise for 12 weeks or treated with FPS-ZM1, an inhibitor of RAGE. Exercise training attenuated aortic stiffening with age marked by reduced collagen levels, increased elastin levels and reduced pulse wave velocity (PWV), and prevented aging-related endothelial dysfunction marked by restored endothelium-mediated vascular relaxation of aortas in response to acetylcholine. Exercise training in aging aortas reduced formation of malondialdehyde, 3-nitrotyrosin and reactive oxygen species, increased GSH/GSSG ratio, suppressed activation of NFκB, and reduced levels of IL-6 and chemokine (C-C motif) ligand 2. Similar effects were demonstrated in aged rats treated with FPS-ZM1. Collectively, exercise suppressed advanced glycation in the aortas of aged rats, which, at least in part, explained the vasculature-protecting effects of exercise training in aged population.

Nitrosative stress in human skeletal muscle attenuated by exercise countermeasure after chronic disuse

Activity-induced nitric oxide (NO) imbalance and "nitrosative stress" are proposed mechanisms of disrupted Ca(2+) homeostasis in atrophic skeletal muscle. We thus mapped S-nitrosylated (SNO) functional muscle proteins in healthy male subjects in a long-term bed rest study (BBR2-2 Study) without and with exercise as countermeasure in order to assess (i) the negative effects of chronic muscle disuse by nitrosative stress, (ii) to test for possible attenuation by exercise countermeasure in bed rest and (iii) to identify new NO target proteins. Muscle biopsies from calf soleus and hip vastus lateralis were harvested at start (Pre) and at end (End) from a bed rest disuse control group (CTR, n=9) and two bed rest resistive exercise groups either without (RE, n=7) or with superimposed vibration stimuli (RVE, n=7). At subcellular compartments, strong anti-SNO-Cys immunofluorescence patterns in control muscle fibers after bed rest returned to baseline following vibration exercise. Total SNO-protein levels, Nrf-2 gene expression and nucleocytoplasmic shuttling were changed to varying degrees in all groups. Excess SNO-protein levels of specific calcium release/uptake proteins (SNO-RyR1, -SERCA1 and -PMCA) and of contractile myosin heavy chains seen in biopsy samples of chronically disused skeletal muscle were largely reduced by vibration exercise. We also identified NOS1 as a novel NO target in human skeletal muscle controlled by activity driven auto-nitrosylation mechanisms. Our findings suggest that aberrant levels of functional SNO-proteins represent signatures of uncontrolled nitrosative stress management in disused human skeletal muscle that can be offset by exercise as countermeasure.

Exploring the role of genetic variability and lifestyle in oxidative stress response for healthy aging and longevity

Oxidative stress is both the cause and consequence of impaired functional homeostasis characterizing human aging. The worsening efficiency of stress response with age represents a health risk and leads to the onset and accrual of major age-related diseases. In contrast, centenarians seem to have evolved conservative stress response mechanisms, probably derived from a combination of a diet rich in natural antioxidants, an active lifestyle and a favorable genetic background, particularly rich in genetic variants able to counteract the stress overload at the level of both nuclear and mitochondrial DNA. The integration of these factors could allow centenarians to maintain moderate levels of free radicals that exert beneficial signaling and modulator effects on cellular metabolism. Considering the hot debate on the efficacy of antioxidant supplementation in promoting healthy aging, in this review we gathered the existing information regarding genetic variability and lifestyle factors which potentially modulate the stress response at old age. Evidence reported here suggests that the integration of lifestyle factors (moderate physical activity and healthy nutrition) and genetic background could shift the balance in favor of the antioxidant cellular machinery by activating appropriate defense mechanisms in response to exceeding external and internal stress levels, and thus possibly achieving the prospect of living a longer life.

Modulation of endogenous antioxidant activity by resveratrol and exercise in mouse liver is age dependent

Aging is a multifactorial process in which oxidative damage plays an important role. Resveratrol (RSV) and exercise delay some of the damages occurring during aging and increase life span and health span. We treated mice at different ages with RSV during 6 months and trained them during the last 6 weeks to determine if RSV and exercise induce changes in endogenous antioxidant activities in liver and if their effects depend on the age of the animal at the beginning of the intervention. Aging was accompanied by the increase in oxidative damage in liver especially affecting the glutathione-dependent system. Both RSV and exercise reversed the effect of aging and maintained high activities of glutathione, glutathione peroxidase, and glutathione transferase activities in old animals.

NAD(P)H

quinone acceptor oxidoreductase activity was also increased. Modulation of antioxidant activities was not completely accompanied by changes at the protein level. Whereas glutathione peroxidase 1 protein increased in parallel to the higher activity in old animals,

NAD(P)H

quinone acceptor oxidoreductase protein decreased by RSV although the activity was enhanced. Our results indicate that RSV and exercise revert the effect of aging in liver of old animals maintaining higher antioxidant activities and decreasing oxidative damage. Short-term interventions are enough to produce beneficial effects of RSV or exercise at later ages.

Prostate cancer and physical activity: adaptive response to oxidative stress

Prostate cancer is the most common form of cancer affecting men in the Western world. Its relative incidence increases exponentially with age and a steady increase is observed with extended life span. A sedentary lifestyle represents an important risk factor and a decrease in prostate cancer prevalence is associated with exercise. However, the molecular mechanisms involved in this process remain unknown. We hypothesize that reactive oxygen species generated by physical exercise are a key regulatory factor in prostate cancer prevention. Aging is correlated with increased oxidative stress (OS), which in turn provides a favorable environment for tumorigenesis. Running training is known to enhance the antioxidant defense system, reducing oxidative stress. In this context, the decrease in OS induced by exercise may delay the development of prostate cancer. This review focuses on oxidative stress-based mechanisms leading to prostate cancer sensitization to exercise, which could have some impact on the development of novel cancer therapeutic strategies.

The effects of a long-term physical activity intervention on serum uric acid in older adults at risk for physical disability

Observational studies show a relationship between elevated serum uric acid (UA) and better physical performance and muscle function. The purpose of this paper was to determine whether regular participation in an exercise intervention, known to improve physical functioning, would result in increased serum UA. For this study, 424 older adults at risk for physical disability were randomized to participate in either a 12-mo moderate-intensity physical activity (PA) or a successful aging (SA) health education intervention. UA was measured at baseline, 6, and 12 mo (n = 368, 341, and 332, respectively). Baseline UA levels were 6.03 ± 1.52 mg/dl and 5.94 ± 1.55 mg/dl in the PA and SA groups, respectively. The adjusted mean UA at month 12 was 4.8% (0.24 mg/dl) higher in the PA compared with the SA group (p = .028). Compared with a health education intervention, a 1-yr PA intervention results in a modest increase in systemic concentration of UA in older adults at risk for mobility disability.

Effect of an 8-weeks aerobic training program in elderly on oxidative stress and HSP72 expression in leukocytes during antioxidant supplementation

OBJECTIVE

To investigate the effect of aerobic training in the context of antioxidant supplementation on systemic oxidative stress and leukocytes heat shock protein (Hsp)72 expression in the elderly.

DESIGN

Sixteen septuagenarians (8 males and 8 females, mean age 74.6) were supplemented with Vitamin C and E (respectively 500 and 100mg per day) and randomly assigned either to sedentary (AS) or individualized aerobically trained (AT) group for 8 weeks.

METHODS

Plasma Vitamin C and E concentrations and aerobic fitness, as well as resting and post graded exercise (GXT) Hsp72 expression in leukocytes, plasma levels of thiobarbituric acid reactive substances (TBARS) and advanced oxidation protein product (AOPP) were measured pre and post training / supplementation.

RESULTS

At the end of the intervention, the two groups showed a significant increase in resting plasma vitamin C and E (approximately 50 and 20% increase respectively) and a significant decrease in both resting and post GXT plasma TBARS and AOPP (approximately 25 and 20% decrease respectively). These changes were of similar magnitude in the two groups. The reduced oxidative stress was concomitant with a 15% decreased expression of Hsp72 in monocytes and granulocytes in both groups.

CONCLUSION

This study provides evidence that in elderly, increased concentration of antioxidant vitamins C and E is associated with a reduction in oxidative stress and leukocytes Hsp72. In this context, 8 weeks of aerobic training has no impact on oxidative stress or leukocytes Hsp72 expression in elderly people.

Resistance loading and signaling assays for oxidative stress in rodent skeletal muscle

Resistance loading provides an important tool for understanding skeletal muscle responses and adaptations to various perturbations. A model using anesthetized rodents provides the means to control the input parameters carefully, and to measure the output parameters of each muscle contraction. Unilateral models of anesthetized loading also provide the advantage of comparing an unloaded and loaded muscle from the same animal. Voluntary models for resistance loading arguably provide a more "physiological response" but it also introduces more variability in the input parameters, which can be affected by the stimulus used to motivate the animal to exercise. After either acute or chronic periods of muscle loading, the loaded muscles can be removed and various signaling proteins can be determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) or enzyme assays. Several assays are described, which provide an indication of downstream markers for oxidative stress.

The physiological roles of Sirt1 in skeletal muscle

Skeletal muscle aging is associated with increased inflammation and oxidative stress, a decrease in the ability to rebuild muscle after injury and in response to exercise. In this perspective, we discuss the mechanisms regulating Sirt1 activity and expression in skeletal muscles, emphasizing their implications in muscle physiology and the impairment of muscle function with age.

The paradox of oxidative stress and exercise with advancing age

Aging, vascular function, and exercise are thought to have a common link in oxidative stress. Both antioxidant supplementation and exercise training have been identified as interventions that may reduce oxidative stress, but their interaction in older humans is not well understood.

Inhibition of xanthine oxidase reduces oxidative stress and improves skeletal muscle function in response to electrically stimulated isometric contractions in aged mice

Oxidative stress is a putative factor responsible for reducing function and increasing apoptotic signaling in skeletal muscle with aging. This study examined the contribution and functional significance of the xanthine oxidase enzyme as a potential source of oxidant production in aged skeletal muscle during repetitive in situ electrically stimulated isometric contractions. Xanthine oxidase activity was inhibited in young adult and aged mice via a subcutaneously placed time-release (2.5mg/day) allopurinol pellet, 7 days before the start of in situ electrically stimulated isometric contractions. Gastrocnemius muscles were electrically activated with 20 maximal contractions for 3 consecutive days. Xanthine oxidase activity was 65% greater in the gastrocnemius muscle of aged mice compared to young mice. Xanthine oxidase activity also increased after in situ electrically stimulated isometric contractions in muscles from both young (33%) and aged (28%) mice, relative to contralateral noncontracted muscles. Allopurinol attenuated the exercise-induced increase in oxidative stress, but it did not affect the elevated basal level of oxidative stress that was associated with aging. In addition, inhibition of xanthine oxidase activity decreased caspase-3 activity, but it had no effect on other markers of mitochondrial-associated apoptosis. Our results show that compared to control conditions, suppression of xanthine oxidase activity by allopurinol reduced xanthine oxidase activity, H₂O₂ levels, lipid peroxidation, and caspase-3 activity; prevented the in situ electrically stimulated isometric contraction-induced loss of glutathione; prevented the increase in catalase and copper-zinc superoxide dismutase activities; and increased maximal isometric force in the plantar flexor muscles of aged mice after repetitive electrically evoked contractions.

Influence of physical activity intensity and aerobic fitness on the anthropometric index and serum uric acid concentration in people with obesity

BACKGROUND AND OBJECTIVE

Physical activity (PA) is considered an important approach to prevent and treat obesity and hyperuricemia. The purpose of the present study was to examine the influence of PA intensity and aerobic fitness on anthropometric indices and serum uric acid in obese individuals.

METHODS

PA was examined using a single-axial accelerometer and aerobic fitness was assessed by electric cycle ergometry in obese middle-aged men (n=71, 47.2 ± 4.4 years). PA was defined as light (<3 metabolic equivalents [METs]), moderate (3.0-6.0 METs) or vigorous (>6.0 METs) intensity from the corresponding METs multiplied by time spent at the corresponding intensity levels. Serum uric acid was measured by the uricase peroxidase method.

RESULTS

The association between aerobic fitness index (lactate threshold) and serum uric acid did not reach statistical significance after adjustment for potential confounding factors (age, body mass index [BMI], and alcohol consumption) (β=-0.110, p=0.138). Light intensity PA was inversely associated with BMI and waist circumference, even after adjustment for age and alcohol consumption (BMI: β=-0.543, p=0.023; waist circumference: β=-1.333, p=0.016). Moderate intensity PA, but not light or vigorous intensity PA, was inversely correlated with the uric acid level and this remained significant after adjustment for age, BMI, and alcohol consumption (β=-0.222, p=0.036).

CONCLUSION

Our results suggest that light intensity PA may have an important role in weight control while moderate intensity PA may be associated with the lower uric acid concentrations in obese individuals.

Effects of aerobic training on oxidative status in postsurgical non-small cell lung cancer patients: a pilot study

BACKGROUND

Oxidative stress is postulated to contribute to the initiation, promotion, and progression of non-small cell lung cancer (NSCLC). We investigated the effects of supervised, moderate-intensity aerobic training on urinary markers of oxidative status in patients with postsurgical NSCLC.

PATIENTS AND METHODS

Sixteen patients with histologically confirmed stage I-IIIB NSCLC were recruited. Exercise training consisted of aerobic cycle ergometry sessions at 60 to ≥70% of baseline peak workload 20-45 min·d(-1), 3 d·wk(-1)for 14 weeks. Oxidative status was assessed via four urinary F(2)-isoprostanes isomers: iPF (2-alpha)-III, 2,3-dinor-iPF(2 alpha)-III, iPF (2-alpha)-VI, and 8,12-iso-iPF(2 alpha)-VI using liquid chromatography with tandem mass spectrometry detection. Peak oxygen consumption (VO2peak) was assessed using a maximal, incremental, cardiopulmonary exercise test with expired gas analysis.

RESULTS

A composite index of all four F2-isoprostanes isomers increased from baseline to post-intervention by 32% (p = 0.08). Concerning individual isomers, iPF (2-alpha)-III increased by 0.09 (+55%; p = .010), iPF (2-alpha)-VI by 0.81 (+29%; p = 0.04), and 8,12-iso-iPF(2 alpha)-VI by 0.59 (+28%; p = 0.07) from baseline to postintervention. There was no change in 2,3-dinor-iPF(2 alpha)-III levels. VO2peak increased 1.1 mL·kg·(-1) min(-1) (p = 0.14) and peak workload increased 10 Watts (p < .001). Change in VO2peak was not associated with change in markers of oxidative status.

CONCLUSIONS

Aerobic training was associated with significant increases in urinary measures of oxidative status in postsurgical NSCLC. The clinical implications of these findings are currently unknown. Further studies are required to elucidate the complex relationship between aerobic training, oxidative stress, tumor biology, and response to cytotoxic agents in mouse and human models of cancer.

Physical inactivity and cardiovascular risk: baseline observations from men and premenopausal women

INTRODUCTION

Physical activity or exercise is a proven deterrent of cardiovascular (CV) diseases.

PURPOSE

In this study, we examined the relationships between baseline values of parameters related to physical activity and known markers of CV disease, including markers of oxidative stress.

METHODS

A total of 455 healthy men and women between the ages of 18 and 50 were recruited to participate in the study. Levels of lipids/lipoproteins and markers of oxidative stress and inflammation were measured along with the VO(2) and duration time spent on treadmill.

RESULTS

Women, in general, had a significantly (P<0.0001) higher plasma high density lipoprotein (1.51+/-0.30 mmol/l), decreased (P<0.0001) low density lipoprotein (LDL) (2.75+/-0.66 mmol/l), and decreased (P<0.0001) triglycerides levels (2.09+/-0.85 mmol/l), compared with males (1.21+/-0.23 mmol/l, 2.92+/-0.81 mmol/l, and 3.02+/-1.34 mmol/l, respectively). There was a direct correlation between the levels of plasma LDL and the levels oxidized LDL levels (P<0.0001) in both men and women. Despite a better antiatherogenic lipid profile, the levels of C-reactive protein in women were significantly (P<0.0001) elevated (3.78+/-3.66 ng/ml) as compared with those in men (1.82+/-2.37 ng/ml).

CONCLUSION

These results suggest intrinsic sex differences between men and women in relation to atherogenic risk.

Suppression of oxidative stress by resveratrol after isometric contractions in gastrocnemius muscles of aged mice

This study tested the hypothesis that resveratrol supplementation would lower oxidative stress in exercised muscles of aged mice. Young (3 months) and aged (27 months) C57BL/6 mice received a control or a 0.05% trans-resveratrol-supplemented diet for 10 days. After 7 days of dietary intervention, 20 maximal electrically evoked isometric contractions were obtained from the plantar flexors of one limb in anesthetized mice. Exercise was conducted for three consecutive days. Resveratrol supplementation blunted the exercise-induced increase in xanthine oxidase activity in muscles from young (25%) and aged (53%) mice. Resveratrol lowered H(2)O(2) levels in control (13%) and exercised (38%) muscles from aged animals, reduced Nox4 protein in both control and exercised muscles of young (30%) and aged mice (40%), and increased the ratio of reduced glutathione to oxidized glutathione in exercised muscles from young (38%) and aged (135%) mice. Resveratrol prevented the increase in lipid oxidation, increased catalase activity, and increased MnSOD activity in exercised muscles from aged mice. These data show that dietary resveratrol suppresses muscle indicators of oxidative stress in response to isometric contractions in aged mice.

Aberrant mitochondrial homeostasis in the skeletal muscle of sedentary older adults

The role of mitochondrial dysfunction and oxidative stress has been extensively characterized in the aetiology of sarcopenia (aging-associated loss of muscle mass) and muscle wasting as a result of muscle disuse. What remains less clear is whether the decline in skeletal muscle mitochondrial oxidative capacity is purely a function of the aging process or if the sedentary lifestyle of older adult subjects has confounded previous reports. The objective of the present study was to investigate if a recreationally active lifestyle in older adults can conserve skeletal muscle strength and functionality, chronic systemic inflammation, mitochondrial biogenesis and oxidative capacity, and cellular antioxidant capacity. To that end, muscle biopsies were taken from the vastus lateralis of young and age-matched recreationally active older and sedentary older men and women (N = 10/group; female symbol = male symbol). We show that a physically active lifestyle is associated with the partial compensatory preservation of mitochondrial biogenesis, and cellular oxidative and antioxidant capacity in skeletal muscle of older adults. Conversely a sedentary lifestyle, associated with osteoarthritis-mediated physical inactivity, is associated with reduced mitochondrial function, dysregulation of cellular redox status and chronic systemic inflammation that renders the skeletal muscle intracellular environment prone to reactive oxygen species-mediated toxicity. We propose that an active lifestyle is an important determinant of quality of life and molecular progression of aging in skeletal muscle of the elderly, and is a viable therapy for attenuating and/or reversing skeletal muscle strength declines and mitochondrial abnormalities associated with aging.