The main purpose of this study is to determine whether pharmacological treatment with N-acetylcysteine improves central and peripheral cardiorespiratory control and physical capacity in COPD patients with mild-to-moderate airflow obstruction.
Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. Cardiovascular complications constitute the main causes of poor physical capacity and healthcare resources utilization in COPD. There is emerging evidence that these impairments have a major impact on the health of patients with mild-to-moderate disease, the largest sub-population of COPD. This important problem, however, is currently neglected as no specific pharmacological treatment is offered to these patients. Recent studies indicate that vascular abnormalities are mediated, at least in part, by circulating inflammatory substances and direct damage of the arteries by oxygen radicals (oxidative stress). The current investigation will test the hypothesis that N-acetylcysteine (NAC), via its anti-inflammatory and antioxidant properties, improves systemic vascular function and physical capacity in COPD patients with mild-to-moderate airflow obstruction.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
13
Pharmacological treatment with N-acetylcysteine (NAC): 3 pills of 600 mg of NAC/day orally for 4 days prior to experimental procedures and 1 pill of 600 mg of NAC orally on the day of the experiment.
Placebo: 3 placebo pills/day orally for 4 days prior to experimental procedures and 1 placebo pill orally on the day of the experiment.
Plasma Redox Status - Circulating Glutathione
Fluorescent detection of plasma glutathione from samples collected during day 4 of each experimental arm (placebo vs. N-acetylcysteine)
Time frame: pre-exercise value (day 4)
Exercise Capacity - Time to Exhaustion
Cycling time to exhaustion during day 4 of each experimental arm (placebo vs. N-acetylcysteine)
Time frame: end-exercise value (Day 4)
Change in Central Cardiovascular Function - Cardiac Output
During cycling to exhaustion during day 4 of each experimental arm (placebo vs. N-acetylcysteine)
Time frame: end-exercise value (Day 4)
Change in Skeletal Muscle Deoxygenation - Dynamics (Mean Response Time)
Mean response time (MRT) evaluated during cycling to exhaustion during day 4 of each experimental arm (placebo vs. N-acetylcysteine)
Time frame: Day 4
Change in Skeletal Muscle Vascular Function - Capillary Blood Flow Dynamics (Mean Response Time)
Mean response time (MRT) evaluated during cycling to exhaustion during day 4 of each experimental arm (placebo vs. N-acetylcysteine)
Time frame: Day 4
Change in Pulmonary Oxygen Uptake - Dynamics (Mean Response Time)
Mean response time (MRT) evaluated during cycling to exhaustion during day 4 of each experimental arm (placebo vs. N-acetylcysteine)
Time frame: Day 4
Change in Pulmonary Ventilation - Minute Ventilation (VE)
During cycling to exhaustion during day 4 of each experimental arm (placebo vs. N-acetylcysteine)
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Time frame: end-exercise value (Day 4)