Estresse oxidativo e a função endotelial: efeitos do exercício físico associado à lipemia pós-prandial

Organic Beet Leaves and Stalk Juice Attenuates the Glutathione Peroxidase Increase Induced by High-Fat Meal in Dyslipidemic Patients: A Pilot Double-Blind, Randomized, Controlled Trial

The beet, including the leaves and stalk (BLS), is a vegetable with great antioxidant potential. The aim of this study was to evaluate the differences in the nutritional composition and the concentration of total phenolics between the organic and conventional BLS and to verify whether the ingestion of an organic BLS juice containing different concentrations of polyphenols modulated some biomarkers of oxidative stress after the ingestion of a high-fat meal in individuals with dyslipidemia. A controlled, randomized, double-blind, crossover clinical trial with a washout period of 1 week was carried out. A 12-h fasting blood sample was collected. Afterward, the participants consumed a high-fat meal, followed by the ingestion of a placebo or one of the organic BLS juices containing either 32.0 or 77.5 mg/100 mL of polyphenols. Blood samples were obtained 30, 60, 120 and 180 min after the first blood collection. The composition analysis showed that organic BLS had a better nutritional composition than conventional ones. The high-fat meal induced postprandial hypertriglyceridemia after 120 min (p < 0.001) and increased the concentration of malondialdehyde after 30 min (p < 0.001). In addition, there was a significant increase in GPx in 30 min (p = 0.026). This increase was attenuated in the group that received the highest dose of polyphenols when compared with the placebo after 30 min (p = 0.045). Therefore, the organic BLS juice containing 77.5 mg of polyphenols was efficient at modulating one of the postprandial mechanisms of enzymatic antioxidant protection in individuals with dyslipidemia.

Evaluation of the effects produced by subacute tributyltin administration on vascular reactivity of male wistar rats

Tributyltin chloride (TBT) is an organotin compound widely used in several high biocides for agroindustrial applications, such as fungicides, and marine antifouling paints leading to endocrine disrupting actions, such as imposex development in mollusks. In female rats, TBT has been shown to promote ovarian dysfunction, reduction of estrogen protective effect in the vascular morphophysiology, at least in part by oxidative stress consequences. Estrogen causes coronary endothelium-dependent and independent vasodilation. However, the TBT effects on cardiovascular system of male rats are not fully understood. The aim of this study was to evaluate the effects of subacute TBT exposure in aorta vascular reactivity from male wistar rats. Rats were randomly divided into three groups: control (C), TBT 500 ng/kg/day and TBT 1000 ng/kg/day. TBT was administered daily for 30 days by oral gavage. We found that TBT exposure enhanced testosterone serum levels and it was also observed obesogenic properties. TBT exposure evoked an increase in endothelium-dependent and independent phenylephrine-induced contraction, associated to an inhibition in eNOS activity. On the other hand, it was observed an enhancement of iNOS and NF-kB protein expression. We also observed an increase in oxidative stress parameters, such as superoxide dismutase (SOD) and catalase expression, and also an increase in malondialdehyde production. Finally, TBT exposure produced aortic intima-media thickness. Taken together, these data suggest a potential cardiovascular toxicological effect after subacute TBT exposure in male rats.

Effects of Two Combined Exercise Designs Associated With High-Fat Meal Consumption on Postprandial Lipemia, Insulinemia, and Oxidative Stress

Farinha, JB, Macedo, CEO, Rodrigues-Krause, J, Krüger, RL, Boeno, FP, Macedo, RCO, Queiroz, JN, Teixeira, BC, and Reischak-Oliveira, A. Effects of two combined exercise designs associated with high-fat meal consumption on postprandial lipemia, insulinemia, and oxidative stress. J Strength Cond Res 32(5): 1422-1430, 2018-Impaired postprandial lipemia (PPL) response after the consumption of a high-fat meal (HFM) is linked to diabetes, oxidative stress, and cardiovascular events. The aim of this study was to investigate lipid and glucose metabolism and oxidative stress responses of 2 different combined exercise designs associated with HFM consumption. Eleven healthy and physically active men (27.36 ± 5.04 years) participated in this study. After the pretrial visits, participants were randomly assigned to perform 2-day trials in 3 different conditions (interspaced by at least 1 week): resting (REST), circuit combined exercise (CIRC), or traditional combined exercise (COMB), on the evening of day 1. On the morning of day 2, an HFM was provided and blood samples were obtained before and after 1, 3, and 5 hours of HFM consumption. No differences were found with respect to glucose, thiobarbituric acid-reactive substances, or total thiol levels in between time points or conditions. One-way analysis of variance demonstrated a difference between REST and CIRC (p = 0.029; reduction of 35.29%) and between REST and COMB (p = 0.041; reduction of 33.41%) conditions with incremental area under the curve (iAUC) for triacylglycerol levels. A difference between REST and CIRC (p = 0.03; reduction of 34.22%) conditions in terms of iAUC for insulin was also found. Both CIRC and COMB exercise designs can reduce PPL associated with HFM consumption. Moreover, CIRC reduces the iAUC for insulin, suggesting additional benefits for prescribing this type of exercise.

Association between Physical Exercise and Biomarkers of Oxidative Stress among Middle-Aged and Elderly Community Residents with Essential Hypertension in China

This study aimed to investigate the role of different types and frequencies of physical exercise in biomarkers of oxidative stress among middle-aged and elderly community residents with essential hypertension in China. A community-based cross-sectional survey was undertaken in 7 subdistricts. Individuals, 45-79 years old, with essential hypertension (n = 402) and without cardiovascular disease (n = 1047) were included. Superoxide dismutase (SOD) activities and plasma levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) were determined. Multilevel linear regression was used to estimate the associations between various types of physical exercise and oxidative stress biomarker levels. Participants engaged in high frequency walking/square dancing or taiji/yoga demonstrated decreased systolic blood pressure in both groups; however, diastolic blood pressure decreased only among individuals with hypertension participating in walking/square dancing. In individuals with hypertension, MDA levels decreased in those participating in walking/square dancing, SOD activity increased in those participating in walking/square dancing, and 4-HNE levels decreased in those involved in taiji/yoga. In individuals without cardiovascular disease, MDA levels decreased in those involved in walking/square dancing or taiji/yoga, SOD activity increased in those performing walking/square dancing, and 4-HNE levels decreased in those involved in taiji/yoga. Oxidative stress marker levels also improved in those involved in walking/square dancing or taiji/yoga groups as the exercise frequency increased. Thus, frequent participation in walking/square dancing or taiji/yoga effectively decreases hypertension-related oxidative stress biomarker levels.

Effect of exercise intensity on postprandial lipemia, markers of oxidative stress, and endothelial function after a high-fat meal

The aim of this study was to compare the effects of 2 different exercise intensities on postprandial lipemia, oxidative stress markers, and endothelial function after a high-fat meal (HFM). Eleven young men completed 2-day trials in 3 conditions: rest, moderate-intensity exercise (MI-Exercise) and heavy-intensity exercise (HI-Exercise). Subjects performed an exercise bout or no exercise (Rest) on the evening of day 1. On the morning of day 2, an HFM was provided. Blood was sampled at fasting (0 h) and every hour from 1 to 5 h during the postprandial period for triacylglycerol (TAG), thiobarbituric acid reactive substance (TBARS), and nitrite/nitrate (NOx) concentrations. Flow-mediated dilatation (FMD) was also analyzed. TAG concentrations were reduced in exercise conditions compared with Rest during the postprandial period (P < 0.004). TAG incremental area under the curve (iAUC) was smaller after HI-Exercise compared with Rest (P = 0.012). TBARS concentrations were reduced in MI-Exercise compared with Rest (P < 0.041). FMD was higher in exercise conditions than Rest at 0 h (P < 0.02) and NOx concentrations were enhanced in MI-Exercise compared with Rest at 0 h (P < 0.01). These results suggest that acute exercise can reduce lipemia after an HFM. However, HI-Exercise showed to be more effective in reducing iAUC TAG, which might suggest higher protection against postprandial TAG enhancement. Conversely, MI-Exercise can be beneficial to attenuate the susceptibility of oxidative damage induced by an HFM and to increase endothelial function in the fasted state compared with Rest.