Effect of eight weeks aerobic training on plasma level of VEGF and NO in patient's cardiovascular disease after coronary artery bypass graft surgery

Coronary heart disease is the most common disease among cardiovascular diseases and coronary artery bypass graft (CABG) surgery is the first treatment of choice for coronary artery disease. Bypass surgery is a traumatic event, and inflammation is the most common symptom that occurs widely afterwards. The presence of these symptoms reduces patients' quality of life, and evidence suggests that these patients are at risk for new coronary events, readmission, and even death. Failure to treat inflammation has a negative effect on the prognosis of the disease, reducing adherence to its treatment and this may lead to recurrence of the disease in these patients. However, there are modifiable factors such as physical activity that help prevent and treat the disease by regulating the inflammatory process. Studies have shown that the use of exercise interventions is effective in heart patients. Utilization of aerobic activity is considered as a treatment method for the disease and other stressful changes. Each session of exercise leads to the production and release of cytokines from skeletal muscle contraction. One of the challenges that has attracted the attention of sports professionals today is the identification of new training methods on physical factors and physiological factors on performance. Increasing exercise, especially aerobic exercise in cardiovascular patients by reducing plasma lipid and blood glucose levels, reducing oxidative stress and bone density can increase physical function and improve controlled cardiovascular disease and prevent sarcopenia and Osteoporosis is effective. The aim of this study was to determine the effect of eight weeks of aerobic exercise on plasma levels of VEGF and NO in cardiac patients after coronary artery bypass graft surgery.

16 male non-athlete heart patients, after CABG surgery, were selected and randomly divided into two groups of exercise (n=8) and control (n=8). The exercise group performed an aerobic exercise program for 8 weeks, 3 sessions per week and 40 to 50 minutes per session, including running on a treadmill with an intensity of 60 to 75% of maximum heart rate for 10 to 20 minutes. Then the exercise was go on with a manual ergometer with an intensity of 30 to 50 watts for 8 to 10 minutes and then the exercise was performed on a stationary bicycle ergometer. In addition to routine care, the intervention group participated in an 8-week aerobic program. Aerobic exercise for eight weeks (three sessions per week) including 6 to 14 intensity (RPE) intensity training on the Borg pressure scale, for 10 to 20 minutes on a treadmill, then exercise with a manual ergometer at 30 to 50 watts for 8 to 10 minutes and then exercise on a stationary bike with an intensity of 30 to 50 watts for 8 to 10 minutes, under the supervision of a sports medicine specialist, exercise physiologist and nurse. The control group received only daily care under the supervision of a physician for 8 weeks. Blood samples were taken in both groups before and after 8 weeks and their VEGF and NO variables were measured by ELISA. Initial blood sampling was performed 48 hours before the first training session of all subjects in the fasting state in which 5 cc of blood was taken from the brachial vein of the samples. Also, 48 hours after the last training session, 5 cc of blood was taken from the brachial vein of the subjects in order to eliminate the effect of training on all fasting subjects. Subjects were asked to abstain from food for 12 hours before blood sampling until blood sampling. Serum levels of VEGF and NO were measured by ELIZA and the data were analyzed using Paired sample t-test and independent sample t-test (α£.05).

The results showed that VEGF, 52.72% (p <0.001) and NO, 72.19% (p <0.001) levels increased significantly. While in VEGF control group, 0.24% (p <0.982) decreased non-significant and NO, 5.20% (p <0.343) increased non-significant.

According to the results of the study, eight weeks of moderate-intensity aerobic exercise increases serum VEGF and NO and accelerates the rehabilitation of cardiac patients after coronary artery bypass graft surgery. Among the possible physiological stimuli for oxidantric production is known to be increased blood flow in the venous duct, which in its acute effect increases oxidative nitric synthase and modulates vasodilation to balance pressure. These findings reinforce the possibility that because regular exercise repeatedly increases pulse pressure and pulsation, it may increase the bioavailability of nitric oxide. In addition, several studies have focused on the interaction between HSP-90 and endothelial oxidase synthase. HSP-90, which acts as an intracellular protector, is present in most cells, including endothelial cells, and is released in response to various stimuli, including stress and mechanical shock, and the production of free radicals and oxidative damage. Exercise is also a physiological stimulus for HSP90. In this regard, HSP-90 increases endothelial oxidase synthase enzyme in endothelial cells in response to exercise-induced stimulation, and as a result, exercise improves vascular endothelial function.