Disfunção endotelial no diabetes melito e estados de resistência à insulina: papel do estresse oxidativo e potenciais oportunidades terapêuticas

Excessive consumption of fructose causes cardiometabolic dysfunctions through oxidative stress and inflammation

A rapid rise in obesity, as well as physical inactivity, in industrialized countries is associated with fructose-consumption-mediated metabolic syndrome having a strong association with cardiovascular disease. Although insulin resistance is thought to be at the core, visceral obesity, hypertension, and hypertriglyceridemia are also considered important components of this metabolic disorder. In addition, various other abnormalities such as inflammation, oxidative stress, and elevated levels of uric acid are also part of this syndrome. Lifestyle changes through improved physical activity, as well as nutrition, are important approaches to minimize metabolic syndrome and its deleterious effects.

Walking promotes metabolic and baroreflex sensitivity improvement in fructose-fed male rats

The aim of this study was to investigate metabolic and cardiovascular responses to walking in fructose-fed rats. Male Wistar rats were divided into control (C), sedentary fructose (SF) and walking fructose (WF). Fructose-fed rats received D-fructose (100 g/l). WF rats walked on a treadmill at constant load (0.3 km/h) during 1 h/day, 5 days/week for 8 weeks. Measurements of triglyceride concentrations, adipose tissue and glycemia were carried out together with insulin tolerance test to evaluate metabolic profile. Arterial pressure (AP) signals were directly recorded. Baroreflex sensitivity (BR) was evaluated by the reflex tachycardia (TR) and bradycardia (BR) to AP changes. The results showed that walking decreased the adipose tissue (SF: 6.5 ± 0.4; WF: 2.8 ± 0.1; C: 3.0 ± 0.3 g), blood triglyceride levels (SF: 291 ± 6.5; WF: 150 ± 8.1; C: 103 ± 4.5 mg/dl) and increased insulin sensitivity (SF: 2.5 ± 0.2; WF: 3.3 ± 0.32; C: 4.8 ± 0.4 %/min). Baroreflex sensitivity was improved in the WF group expressed by BR (SF: 0.75 ± 0.10; WF: 1.18 ± 0.10; C: 1.5 ± 0.14 ms/mmHg) and TR (SF: 0.80 ± 0.12; WF: 1.21 ± 0.10; C: 1.35 ± 0.11 ms/mmHg), as well as when verified by the alpha index. Although the WF group showed decreased AP when compared with the SF group, the values still enhanced in relation to C rats (SF: 137 ± 2; WF: 129 ± 1; C: 115 ± 6 mmHg). Our findings allow a better understanding of the effects of walking, a low-intensity exercise training, on the hemodynamic and metabolic aspects of male rats with metabolic syndrome and indicate that walking seems to be particularly effective in treating metabolic disturbances in this model.