Janaina de Oliveira Brito

Cardiometabolic benefits of exercise training in an experimental model of metabolic syndrome and menopause

ObjectiveThe aim of this study was to investigate the cardiometabolic effects of exercise training in ovariectomized hypertensive rats both submitted and not submitted to fructose overload. MethodsSpontaneously hypertensive ovariectomized rats were divided into sedentary and trained (THO) groups submitted to normal chow and sedentary and trained groups submitted to fructose overload (100 g/L in drinking water for 19 wk). Exercise training was performed on a treadmill (8 wk). Arterial pressure (AP) was directly recorded. Cardiovascular autonomic control was evaluated through pharmacological blockade (atropine and propranolol) and in the time and frequency domains by spectral analysis. ResultsThe THO group presented reduced AP (approximately 16 mm Hg) and enhanced cardiac vagal tonus (approximately 49%) and baroreflex sensitivity (approximately 43%) compared with the sedentary hypertensive ovariectomized group. Exercise training attenuated metabolic impairment, resting tachycardia, cardiac and vascular sympathetic increases, and baroreflex sensitivity decrease induced by fructose overload in hypertensive rats. However, the trained hypertensive ovariectomized group submitted to fructose overload presented higher AP (approximately 32 mm Hg), associated with baroreflex sensitivity (approximately 69%) and parasympathetic dysfunctions compared with the THO group. ConclusionsThese data suggest that the metabolic disorders in hypertensive rats after ovarian hormone deprivation could blunt and/or attenuate some exercise training benefits.

Positive effect of combined exercise training in a model of metabolic syndrome and menopause: autonomic, inflammatory, and oxidative stress evaluations.

It is now well established that after menopause cardiometabolic disorders become more common. Recently, resistance exercise has been recommended as a complement to aerobic (combined training, CT) for the treatment of cardiometabolic diseases. The aim of this study was to evaluate the effects of CT in hypertensive ovariectomized rats undergoing fructose overload in blood pressure variability (BPV), inflammation, and oxidative stress parameters. Female rats were divided into the following groups (n = 8/group): sedentary normotensive Wistar rats (C), and sedentary (FHO) or trained (FHOT) ovariectomized spontaneously hypertensive rats undergoing and fructose overload. CT was performed on a treadmill and ladder adapted to rats in alternate days (8 wk; 40-60% maximal capacity). Arterial pressure (AP) was directly measured. Oxidative stress and inflammation were measured on cardiac and renal tissues. The association of risk factors (hypertension + ovariectomy + fructose) promoted increase in insulin resistance, mean AP (FHO: 174 ± 4 vs. C: 108 ± 1 mmHg), heart rate (FHO: 403 ± 12 vs. C: 352 ± 11 beats/min), BPV, cardiac inflammation (tumor necrosis factor-α-FHO: 65.8 ± 9.9 vs. C: 23.3 ± 4.3 pg/mg protein), and oxidative stress cardiac and renal tissues. However, CT was able to reduce mean AP (FHOT: 158 ± 4 mmHg), heart rate (FHOT: 303 ± 5 beats/min), insulin resistance, and sympathetic modulation. Moreover, the trained rats presented increased nitric oxide bioavailability, reduced tumor necrosis factor-α (FHOT: 33.1 ± 4.9 pg/mg protein), increased IL-10 in cardiac tissue and reduced lipoperoxidation, and increased antioxidant defenses in cardiac and renal tissues. In conclusion, the association of risk factors promoted an additional impairment in metabolic, cardiovascular, autonomic, inflammatory, and oxidative stress parameters and combined exercise training was able to attenuate these dysfunctions.

Cardiovascular autonomic dysfunction and oxidative stress induced by fructose overload in an experimental model of hypertension and menopause

BackgroundMetabolic syndrome is characterized by the association of 3 or more risk factors, including: abdominal obesity associated with an excess of abdominal fat, insulin resistance, type 2 diabetes, dyslipidemia and hypertension. Moreover, the prevalence of hypertension and metabolic dysfunctions sharply increases after the menopause. However, the mechanisms involved in these changes are not well understood. Thus, the aim of this study was to assess the effects of fructose overload on cardiovascular autonomic modulation, inflammation and cardiac oxidative stress in an experimental model of hypertension and menopause.MethodsFemale SHR rats were divided into (n = 8/group): hypertensive (H), hypertensive ovariectomized (HO) and hypertensive ovariectomized undergoing fructose overload (100 g/L in drinking water) (FHO). Arterial pressure (AP) signals were directly recorded. Cardiac autonomic modulation was evaluated by spectral analysis. Oxidative stress was evaluated in cardiac tissue.ResultsAP was higher in the FHO group when compared to the other groups. Fructose overload promoted an increase in body and fat weight, triglyceride concentration and a reduction in insulin sensitivity. IL-10 was reduced in the FHO group when compared to the H group. TNF-α was higher in the FHO when compared to all other groups. Lipoperoxidation was higher and glutathione redox balance was reduced in the FHO group when compared to other groups, an indication of increased oxidative stress. A negative correlation was found between IL-10 and adipose tissue.ConclusionFructose overload promoted an impairment in cardiac autonomic modulation associated with inflammation and oxidative stress in hypertensive rats undergoing ovarian hormone deprivation.

Simvastatin-induced cardiac autonomic control improvement in fructose-fed female rats.

OBJECTIVE: Because autonomic dysfunction has been found to lead to cardiometabolic disorders and because studies have reported that simvastatin treatment has neuroprotective effects, the objective of the present study was to investigate the effects of simvastatin treatment on cardiovascular and autonomic changes in fructose-fed female rats. METHODS: Female Wistar rats were divided into three groups: controls (n = 8), fructose (n = 8), and fructose+simvastatin (n = 8). Fructose overload was induced by supplementing the drinking water with fructose (100 mg/L, 18 wks). Simvastatin treatment (5 mg/kg/day for 2 wks) was performed by gavage. The arterial pressure was recorded using a data acquisition system. Autonomic control was evaluated by pharmacological blockade. RESULTS: Fructose overload induced an increase in the fasting blood glucose and triglyceride levels and insulin resistance. The constant rate of glucose disappearance during the insulin intolerance test was reduced in the fructose group (3.4±0.32%/min) relative to that in the control group (4.4±0.29%/min). Fructose+simvastatin rats exhibited increased insulin sensitivity (5.4±0.66%/min). The fructose and fructose+simvastatin groups demonstrated an increase in the mean arterial pressure compared with controls rats (fructose: 124±2 mmHg and fructose+simvastatin: 126±3 mmHg vs. controls: 112±2 mmHg). The sympathetic effect was enhanced in the fructose group (73±7 bpm) compared with that in the control (48±7 bpm) and fructose+simvastatin groups (31±8 bpm). The vagal effect was increased in fructose+simvastatin animals (84±7 bpm) compared with that in control (49±9 bpm) and fructose animals (46±5 bpm). CONCLUSION: Simvastatin treatment improved insulin sensitivity and cardiac autonomic control in an experimental model of metabolic syndrome in female rats. These effects were independent of the improvements in the classical plasma lipid profile and of reductions in arterial pressure. These results support the hypothesis that statins reduce the cardiometabolic risk in females with metabolic syndrome.

IMPACT OF COMBINED EXERCISE TRAINING ON CARDIOVASCULAR AUTONOMIC CONTROL AND MORTALITY IN DIABETIC OVARIECTOMIZED RATS

The purpose of this study was to compare the effects of aerobic, resistance, or combined exercise training on cardiovascular autonomic control and mortality in diabetic ovariectomized rats. Female Wistar rats were divided into one of five groups: euglycemic sedentary (ES), diabetic ovariectomized sedentary (DOS), diabetic ovariectomized aerobic-trained (DOTA), diabetic ovariectomized resistance-trained (DOTR), or diabetic ovariectomized aerobic+resistance-trained (DOTC). Arterial pressure (AP) was directly recorded and baroreflex sensitivity was evaluated by heart rate responses to AP changes. Cardiovascular autonomic modulation was evaluated by spectral analyses. No differences were observed in body weight and glycemia between diabetic rats. Animals in the DOTC and DOTA groups exhibited an increase in running time, whereas animals in the DOTC and DOTR groups showed greater strength. Trained groups exhibited improvement in total power and the high-frequency band of pulse interval and reduced mortality (vs. DOS). Animals in the DOTC (bradycardic and tachycardic responses) and DOTA (tachycardic responses) groups exhibited attenuation in baroreflex dysfunction that was observed in DOS and DOTR animals, and an improvement in AP variance. In conclusion, all training protocols led to reduced mortality, which may be due to an increase in physical capacity and to cardiovascular and autonomic benefits following training, regardless of any improvement in glycemic control. In this model, the aerobic and combined trainings seem to promote additional cardiovascular autonomic benefits when compared with resistance training alone.

Influence of Estimated Training Status on Anti and Pro-Oxidant Activity, Nitrite Concentration, and Blood Pressure in Middle-Aged and Older Women

The purpose of this study was to compare the association between anti and pro-oxidant activity, nitrite concentration, and blood pressure (BP) in middle-aged and older women with different levels of estimated training status (TS). The sample consisted of 155 females (50–84 years) who were submitted to a physical examination to evaluate estimated TS through the “Functional Fitness Battery Test,” BP measurements, and plasma blood samples to evaluate pro-oxidant and antioxidant activity and nitrite concentrations. Participants were separated by age into a middle-aged group (<65 years) and an older (≥65 years) group and then subdivided in each group according to TS. Blood biochemistry was similar between groups. On the other hand, protein oxidation was lower in participants with higher TS, independent of age. Older females with higher TS presented higher nitrite concentrations, lower lipoperoxidation, and lower values of BP compared with those with lower TS. Lower GPx activity was observed in participants with higher TS compared with middle-aged with lower TS. Thus, our results suggest that good levels of TS may be associated with lower oxidative stress and higher nitrite concentration and may contribute to maintain normal or reduced blood pressure values.

Training Status as a Marker of the Relationship between Nitric Oxide, Oxidative Stress, and Blood Pressure in Older Adult Women

The purpose of this study was to evaluate the influence of functional fitness and oxidative capacity on the nitric oxide concentration associated with hemodynamic control in older adult women. The sample consisted of 134 women (65.73 ± 6.14 years old). All subjects underwent a physical examination to assess body mass index, waist-hip ratio, body fat measurement by dual energy X-ray absorptiometry, and blood pressure (BP). Training status (TS) was evaluated by indirect determination of maximal oxygen uptake by a treadmill test using Balke protocol modified for older adults. Functional fitness was also evaluated through a “Functional Fitness Battery Test” to determine the general fitness functional index (GFFI). All participants were separated according to the functional fitness (TS1, very weak and weak; TS2, regular; TS3, good and very good). Plasma blood samples were used to evaluate prooxidant and antioxidant activity and nitrite and nitrate concentrations. The general results of this study showed that good levels of TS were related to lower levels of lipoperoxidation and protein damage, higher levels of antioxidant, and higher concentration of nitrite and nitrate. This combination may be responsible for the lower levels of BP in subjects with better TS.

1075 BENEFITS OF RESISTANCE EXERCISE TRAINING IN OVARIECTOMIZED SPONTANEOUSLY HYPERTENSIVE RATS

Background: Hypertension is a major risk factor in the development of cardiovascular disease and increase in menopause women. Aerobic Exercise has been indicated as a nonpharmacological treatment for hypertension, however the benefits of resistance exercise are not well know. Objectives: Investigate the effects of resistance exercise on cardiovascular autonomic control in ovariectomized hypertensive rats Methodos: Female Wistar (W) and spontaneously hypertensive rats (SHR) were divided into 4 groups (n = 8 each): sedentary W (WS), sedentary SHR (HS), sedentary ovariectomized SHR (HSO) and trained ovariectomized SHR (HTO). The resistance exercise training (RT) was performed in a vertical ladder with weights attached to rat tail (8 weeks; 40-50% maximal load). Arterial pressure (AP) and heart rate (HR) were directly recorded and baroreflex sensitivity (BRS) was evaluated by bradycardic (BR) and tachycardic responses (TR). Results: The mean arterial pressure was higher in HSO (180 ± 4.5 mmHg) and HS (172 ± 3.1 mmHg) compared to HTO (158 ± 2.3 mmHg) and WS (113 ± 1.5 mmHg). The RT induced resting bradycardia (HTO: 322 ± 8.6 bpm) in relation to the other groups. The TR was lower in HS (-1.81 ± 0.06 bpm/mmHg) and HSO (-0.92 ± 0.14 bpm/mmHg) in relation to WS (-2.67 ± 0.2 bpm/mmHg), and was additionally attenuated by ovariectomy (HSO vs. HS). The hypertensive groups had lower BR when compared to WS. The HTO group (-1.42 ± 0.1 bpm/mmHg) showed higher TR in relation to HSO group. Conclusions: Moderate intensity dynamic resistance exercise training induced a reduction in blood pressure and attenuated baroreflex dysfunction in ovariectomized hypertensive rats, suggesting a positive role of this nonpharmacological approach in the management of cardiovascular risk in hypertension after hormones deprivation.