Antoni Sureda

Relation between oxidative stress markers and antioxidant endogenous defences during exhaustive exercise

Hydrogen peroxide (H2O2) could induce oxidative damage at long distance from its generation site and it is also an important signalling molecule that induces some genes related to oxidative stress. Our objective was to study the plasma and blood cells capability to detoxify H2O2 after intense exercise and its correlation with oxidative damage. Blood samples were taken from nine professional cycling, participating in a mountain stage, under basal conditions and 3 h after the competition. Catalase and glutathione peroxidase activities decreased (40 and 50% respectively) in neutrophils after the cycling stage, while glutathione peroxidase increased (87%) in lymphocytes. Catalase protein levels and catalase specific activity maintained basal values after the stage in plasma. Catalase protein levels decreased (48%) in neutrophils and its specific activity increased up to plasma values after exercise. Myeloperoxidase (MPO) increased (39%) in neutrophils after the cycling stage. Exercise-induced hemolysis and lymphopenia inversely correlated with cellular markers of oxidative stress. Plasma malondialdehyde (MDA) directly correlated with neutrophil MPO activity and erythrocytes MDA. Intense exercise induces oxidative damage in blood cells as erythrocytes and lymphocytes, but not in neutrophils.

Dietary sources of omega 3 fatty acids: public health risks and benefits

Omega 3 fatty acids can be obtained from several sources, and should be added to the daily diet to enjoy a good health and to prevent many diseases. Worldwide, general population use omega-3 fatty acid supplements and enriched foods to get and maintain adequate amounts of these fatty acids. The aim of this paper was to review main scientific evidence regarding the public health risks and benefits of the dietary sources of omega-3 fatty acids. A systematic literature search was performed, and one hundred and forty-five articles were included in the results for their methodological quality. The literature described benefits and risks of algal, fish oil, plant, enriched dairy products, animal-derived food, krill oil, and seal oil omega-3 fatty acids.

The Effect of Nitric-Oxide-Related Supplements on Human Performance

Nitric oxide (NO) has led a revolution in physiology and pharmacology research during the last two decades. This labile molecule plays an important role in many functions in the body regulating vasodilatation, blood flow, mitochondrial respiration and platelet function. Currently, it is known that NO synthesis occurs via at least two physiological pathways: NO synthase (NOS) dependent and NOS independent. In the former, L-arginine is the main precursor. It is widely recognized that this amino acid is oxidized to NO by the action of the NOS enzymes. Additionally, L-citrulline has been indicated to be a secondary NO donor in the NOS-dependent pathway, since it can be converted to L-arginine. Nitrate and nitrite are the main substrates to produceNO via the NOS-independent pathway. These anions can be reduced in vivo to NO and other bioactive nitrogen oxides. Other molecules, such as the dietary supplement glycine propionyl-L-carnitine (GPLC), have also been suggested to increase levels of NO, although the physiological mechanisms remain to be elucidated. The interest in all these molecules has increased in many fields of research. In relation with exercise physiology, it has been suggested that an increase in NO production may enhance oxygen and nutrient delivery to active muscles, thus improving tolerance to physical exercise and recovery mechanisms. Several studies using NO donors have assessed this hypothesis in a healthy, trained population. However, the conclusions from these studies showed several discrepancies. While some reported that dietary supplementation with NO donors induced benefits in exercise performance, others did not find any positive effect. In this regard, training status of the subjects seems to be an important factor linked to the ergogenic effect of NO supplementation. Studies involving untrained or moderately trained healthy subjects showed that NO donors could improve tolerance to aerobic and anaerobic exercise. However, when highly trained subjects were supplemented, no positive effect on performance was indicated. In addition, all this evidence is mainly based on a young male population. Further research in elderly and female subjects is needed to determine whether NO supplements can induce benefit in exercise capacity when the NO metabolism is impaired by age and/or estrogen status.

Biochemical responses of Mytilus galloprovincialis as biomarkers of acute environmental pollution caused by the Don Pedro oil spill (Eivissa Island, Spain)

In the present work, the potential use of several antioxidant and detoxification biomarkers in the digestive gland of wild mussels (Mytilus galloprovincialis) for biomonitoring the marine pollution induced by the Don Pedro oil spill has been investigated. Two locations from the East to South-East of Eivissa (Ibiza) and Formentera islands were selected, one extensively affected by the oil spill and the other one not affected and considered as the control area. Mussels were sampled one, two and six months after the Don Pedro accident. Polycyclic aromatic hydrocarbon (PAH) levels were significantly increased in the soft tissues of mussels in the affected area one month after the disaster, returning to normal values after six months. Markers of oxidative damage in lipids--malondialdehyde, and in proteins--carbonyl derivates, and antioxidant enzyme--catalase, superoxide dismutase and glutathione peroxidase, activities significantly increased as result of the spill oil after one month, returning to basal values at two month sampling time. Glutathione/glutathione disulfide ratio (GSH/GSSG), as a marker of the redox status, was reduced after one and two months indicating a more oxidized situation. Markers of detoxification--glutathione-S-transferase and cytochrome P4501A activities and metallothionein gene expression--were significantly increased by the oil spill one month after the accident, returning to the basal values at two month sampling time. In conclusion, the Don Pedro accident induced a transient situation of PAHs pollution resulting in enhanced antioxidant and detoxification defense systems in the wild mussel M. galloprovincialis returning to normal levels six months from the spill. The selected biomarkers are a useful tool for biomonitoring the response to acute exposure to pollutants in marine mussels.

Sodium Nitrate Supplementation Does Not Enhance Performance of Endurance Athletes

PURPOSE Supplementation with inorganic nitrate has been suggested to be an ergogenic aid for athletes as nitric oxide donor. The purpose of this study was to determine whether ingestion of inorganic sodium nitrate benefits well-trained athletes performing a 40-min exercise test in laboratory conditions. In addition, we investigated the effect of this supplement on plasma levels of endothelin-1 (ET-1) and in nitrated proteins. METHODS Thirteen trained athletes participated in this randomized, double-blind, crossover study. They performed a 40-min cycle ergometer distance-trial test after two 3-d periods of dietary supplementation with sodium nitrate (10 mg·kg of body mass) or placebo. RESULTS Concentration of plasma nitrate (256 ± 35 μM) and nitrite (334 ± 86 nM) increased significantly (P < 0.05) after nitrate supplementation compared with placebo (nitrate: 44 ± 11 μM; nitrite: 187 ± 43 nM). In terms of exercise performance, there were no differences in either the mean distance (nitrate: 26.4 ± 1.1 km; placebo: 26.3 ± 1.2 km; P = 0.61) or mean power output (nitrate: 258 ± 28 W; placebo: 257 ± 28 W; P = 0.89) between treatments. Plasma ET-1 increased significantly (P < 0.05) just after exercise in nitrate (4.0 ± 0.8 pg·mL) and placebo (2.4 ± 0.4 pg·mL) conditions. This increase was significantly greater (P < 0.05) in the nitrate group. Levels of nitrated proteins did not differ between treatments (nitrate: preexercise, 91% ± 23%; postexercise, 81% ± 23%; placebo: preexercise, 95% ± 20%; postexercise, 99% ± 19%). CONCLUSION Sodium nitrate supplementation did not improve a 40-min distance-trial performance in endurance athletes. In addition, concentration of plasma ET-1 increased significantly after exercise after supplementation with sodium nitrate.

Kaempferol and inflammation: From chemistry to medicine.

Inflammation is an important process of human healing response, wherein the tissues respond to injuries induced by many agents including pathogens. It is characterized by pain, redness and heat in the injured tissues. Chronic inflammation seems to be associated with different types of diseases such as arthritis, allergies, atherosclerosis, and even cancer. In recent years natural product based drugs are considered as the novel therapeutic strategy for prevention and treatment of inflammatory diseases. Among the different types of phyto-constituents present in natural products, flavonoids which occur in many vegetable foods and herbal medicines are considered as the most active constituent, which has the potency to ameliorate inflammation under both in vitro and in vivo conditions. Kaempferol is a natural flavonol present in different plant species, which has been described to possess potent anti-inflammatory properties. Despite the voluminous literature on the anti-inflammatory effects of kaempferol, only very limited review articles has been published on this topic. Hence the present review is aimed to provide a critical overview on the anti-inflammatory effects and the mechanisms of action of kaempferol, based on the current scientific literature. In addition, emphasis is also given on the chemistry, natural sources, bioavailability and toxicity of kaempferol.

Antioxidant regulatory mechanisms in neutrophils and lymphocytes after intense exercise

Abstract The aims of this study were to assess the effects of a swimming session on the peripheral blood neutrophil and lymphocyte pro- and antioxidant system, identify any differences between the sexes and the regulatory mechanisms that might induce the immune cell adaptive response to exercise. Twenty-four swimmers (15 males, 9 females) participated in a one-hour swimming session at 75–80% of their maximal capacity. The session induced neutrophilia and decreased antioxidant enzyme activities and ascorbate levels in neutrophils. Malondialdehyde rose in neutrophils in males and females, whereas the carbonyl index only increased in males. Lymphocyte glutathione peroxidase activity was higher in males at baseline and rose as a consequence of exercise. The exercise decreased uncoupling protein-3 and Bcl-2 gene expression. The expression of PPARγ coactivator-1 alpha (PGC-1α) correlated positively with that of sirtuin 3 (SIRT3) and catalase. In summary, a swimming session of one hour at 75–80% of maximal capacity produced oxidative damage in neutrophils and induced the antioxidant defences in lymphocytes. PGC-1α and SIRT3 appear to be key effectors of this adaptive response in lymphocytes. Both the neutrophil and lymphocyte response to exercise were slightly weaker in females than males.

Effects of exercise intensity on lymphocyte H2O2 production and antioxidant defences in soccer players

Objective: Physical exercise is capable of enhancing or suppressing the immune response depending on the intensity and duration of exercise. This study investigated how exercise intensity influences the lymphocyte antioxidant response and the induction of cellular oxidative damage. Design: Eighteen voluntary male pre-professional soccer players participated in this study. Sportsmen played a 60 min training match, and were divided into three groups depending on the intensity degree during the match: low, medium and high intensities. Measurements: Malondialdehyde (MDA), vitamins C and E and haem oxygenase-1 (HO-1) gene expression were measured in lymphocytes. Reactive oxygen species (ROS) production was determined in lymphocytes and neutrophils. Results: Lymphocyte MDA levels and H2O2 production were significantly increased in the group which performed the most intense exercise. Neutrophil counts and ROS production increased progressively with the exercise intensity. Vitamin C significantly decreased after exercise in the highest-intensity group in comparison with initial values, whereas vitamin E levels significantly increased in the medium and high-intensity groups. HO-1 gene expression significantly increased in the medium and high-intensity groups. Conclusions: Exercise intensity affects the lymphocyte and neutrophil oxidant/antioxidant balance, but only exercise of high intensity induces lymphocyte oxidative damage.

Response of antioxidant defences to oxidative stress induced by prolonged exercise: antioxidant enzyme gene expression in lymphocytes

The response of lymphocyte and plasma antioxidant defences to a prolonged exercise as a cycling stage in a professional race was analysed. Antioxidant enzyme activities and gene expression, carbonyl derivative and MDA levels were determined in lymphocytes. Plasma levels of vitamin E, carotenes, protein carbonyl derivatives and the test d-Roms were measured. Significant increases in plasmatic carbonyls and in the test d-Roms were observed after the cycling stage. No significant differences were found in the lymphocyte MDA and carbonyl derivative levels. A significant increase was found in plasma vitamin E concentration after the cycling stage; however, the lymphocyte vitamin E concentration did not change. Significant increases were observed in lymphocyte total superoxide dismutase (SOD) activity and in the levels of CuZn-SOD and Mn-SOD isoenzymes. The moderate levels of oxidative stress in the lymphocyte induced a cellular adaptation to exercise enough to counteract the negative effects of oxidative stress.

Scuba diving enhances endogenous antioxidant defenses in lymphocytes and neutrophils.

The aim was to study the effects of a scuba diving session on the lymphocyte antioxidant system, NO synthesis, the capability to produce reactive oxygen species and the antioxidant response in neutrophils. For that purpose seven male divers performed an immersion at a depth of 40 m for 25 min. The same parameters were measured after an hyperbaric oxygen (HBO) treatment at resting conditions in a hyperbaric chamber. Lymphocyte H2O2 production rose after diving and after HBO treatment. Glutathione peroxidase (GPx) and catalase activities increased after diving in lymphocytes, while after HBO exposure only increased GPx activity. Lymphocyte HO-1 mRNA expression increased after diving and after HBO exposure, while iNOS levels and nitrite levels significantly increased after diving. The hyperoxia associated to scuba diving leads to a condition of oxidative stress with increased lymphocyte H2O2 production, HO-1 expression, NO synthesis and antioxidant enzyme adaptations in order to avoid oxidative damage.