Skeletal muscle adaptation to endurance training in patients with chronic obstructive pulmonary disease.

Abstract

The purpose of this study was to evaluate the physiologic responses to endurance training in patients with moderate to severe airflow obstruction by specifically looking at changes in skeletal muscle enzymatic activities. Eleven patients (age = 65 +/- 7 yr, mean +/- SD, FEV1 = 36 +/- 11% of predicted value, range = 24 to 54%) were evaluated before and after an endurance training program. Each evaluation included a percutaneous biopsy of the vastus lateralis and a stepwise exercise test on an ergocycle up to his/her maximal capacity. VE, VO2, VcO2, and serial arterial lactic acid concentration were measured during the exercise test. The activity of two oxidative enzymes, citrate synthase (CS) and 3-hydroxyacyl-CoA dehydrogenase (HADH), and of three glycolytic enzymes, lactate dehydrogenase, hexokinase, and phosphofructokinase was determined. The training consisted of 30-min exercise sessions on a calibrated ergocycle, 3 times a week for 12 wk. The aerobic capacity was severely reduced at baseline (VO2max = 54 +/- 12% of predicted) and increased by 14% after training (p < 0.05). For an identical exercise workload, there was a significant reduction in VE (34.5 +/- 10.0 versus 31.9 +/- 9.0 L/min, p < 0.05) and in arterial lactic acid concentration (3.4 +/- 1.3 versus 2.8 +/- 0.9 mmol/L, p < 0.01) after training. The lactate threshold also increased after training (p < 0.01) while the activity of the three glycolytic enzymes was similar at the two evaluations. In contrast, the activity of CS and HADH increased significantly after training (22.3 +/- 3.5 versus 25.8 +/- 3.8 mumol/min/g muscle for CS, p < 0.05, and 5.5 +/- 2.9 versus 7.7 +/- 2.5 mumol/min/g for HADH, p < 0.01). A significant inverse relationship was found between the percent changes in the activity of CS and HADH, and the percent changes in arterial lactic acid during exercise (p = 0.01). We conclude that endurance training can reduce exercise-induced lactic acidosis and improve skeletal muscle oxidative capacity in patients with moderate to severe chronic obstructive pulmonary disease (COPD).

Recommendations on the use of exercise testing in clinical practice

“…These tests have been shown to be reliable and reproducible [267]. After exercise training, significant reductions in ventilation [255,256,259,261,268] and lactate levels [255,261,268] at identical submaximal work-rates have been observed. These findings suggest an improvement in aerobic metabolism [255,269] and are in agreement with the observation of a significant increase in oxidative enzyme levels (16-40%) in the quadriceps femoris muscle after a strenuous exercise programme [261].…”

Skeletal muscle microbiopsy: a validation study of a minimally invasive technique

“…However, the current observations argue for a repeatability of the microbiopsy that is certainly comparable with that of the Bergströ m technique, not only over time, but also over different experimental conditions. In this regard, the use of microbiopsies could be envisaged to evaluate with confidence, for example, the effects of several interventions after which biological values are assumed to vary, such as pulmonary rehabilitation [9].…”

“…The first inevitable requirement is the muscle biopsy, since research at the cellular level is essential [9,[26][27][28]. The second requirement, however, is to pursue research goals as noninvasively as possible in these patients [29], which compelled the current authors to search for an acceptable alternative to the Bergströ m technique.…”

“…Their relative invasiveness makes it difficult to obtain several biopsies from the same subjects to study, due to, for instance, the time-course response of the skeletal muscle to interventions, such as exercise training or anabolic drug supplementation [9]. Less invasive alternatives to the semiopen muscle biopsy have been proposed by several authors working in different medical areas, such as muscular oncology [10], neuromuscular diseases [11,12] and cardiac failure [13,14].…”

Skeletal muscle dysfunction and oxidative stress in patients with chronic obstructive lung disease

“…In general, physical exercise training can increase the antioxidant and oxidative capacity in skeletal muscle of healthy subjects 21,41,75,76) . Exercise training has also been reported to improve skeletal muscle oxidative capacity in patients with moderate to severe COPD 77) . In addition, pulmonary rehabilitation has been shown to not only increase exercise capacity but also to decrease exercise-induced oxidative stress in COPD patients 78) , based on exhaled H2O2 and urinary MDA as markers for pulmonary and systemic oxidative stress, respectively.…”