Abstract
There is evidence that myocardial infarction (MI) patients have an inflammatory process that includes skeletal muscles, and exercise has been reported to reduce some inflammatory markers. The aim of this work was to study NO and some inflammatory markers in quadriceps muscle of MI patients before and after cardiac rehabilitation. Muscle biopsy was obtained in 17 MI patients before and after CR and only once in 11 healthy subjects. Several cardiorespiratory and metabolic parameters were evaluated and skeletal muscle levels of nitric oxide synthases, nitrate, nitrite, nitrotyrosine, tumor necrosis factor alpha (TNF-α), transforming growth factor beta (TGF-β), interleukin- 6 (IL-6) and CD154. After CR there was an increase in maximal oxygen consumption (21.2 ± 1.4 vs 25.7 ± 2.5 mL/kg/min, P < 0.0001); work load (116.2 ± 14.9 vs 140 ± 17 W, P < 0.0001); pulmonary ventilation (59.8 ± 7,5 vs 73.8 ± 11.6 L/min, P < 0.0001); anaerobic threshold (53.8% ± 3.5% vs 60.2% ± 3.3% of maximal VO2, P < 0.0001), maximal lactatemia (8.1 ± 1.4 vs 9.3 ± 1.5 mmol/L, P < 0.0001), and oxygen pulse (11.7 ± 1.6 vs 14.0 ± 1.9 mL/pulse, P < 0.0001). CSA of type I fibers increased (4380 ± 1868 vs 5237 ± 1530 μm2, P = 0.02), and nitrate (18.6 ± 3.04 vs 20.7 ± 2.0 ng/mg, P < 0.001). There was a negative correlation between BMI, fat%, waist and hip circumferences and NO synthase, nitrite and nitrate after CR. The inflammatory mediators were higher in patients than in control subjects and did not change with CR. TGF-β correlated directly with nitrite and nitrate and inversely to other inflammatory factors. In conclusion, there is an increase of nitrate post CR, indicating a more effective NO production. TGF-β was related to anti-inflammatory processes even before CR.