Oxidative stress in patients with COPD and pulmonary hypertension.
OBJECTIVE
Oxidative stress plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Oxidant/antioxidant imbalance has also been reported in various forms of pulmonary hypertension. The present study aimed to assess systemic oxidative stress, as reflected by serum malondialdehyde (MDA) concentrations and activities of antioxidant enzymes in erythrocytes [glutathione peroxidase (GPX), superoxide dismutase (SOD) and catalase (CAT)] in patients with and without pulmonary hypertension secondary to COPD.


METHODS
Seventy-five patients (58 male) with COPD (mean age 65.1 +/- 1.2 years; mean smoking history 35.6 +/- 3.8 pack-years) were studied. Twenty-one healthy non-smokers served as a control group. Pulmonary function was evaluated with body plethysmography; mean and systolic pulmonary artery pressures (Ppa) were assessed with Doppler echocardiography. Serum concentrations of MDA and activities of GPX, SOD and CAT in washed red blood cells were measured using spectrophotometry.


RESULTS
Pulmonary hypertension was present in 28 patients with COPD (systolic Ppa: 46.4 +/- 2.3 mmHg; mean Ppa: 26.0 +/- 1.9 mmHg) and absent in 47 (systolic Ppa: 22.9 +/- 0.8 mmHg; mean Ppa: 13.4 +/- 0.6 mmHg). Compared with the healthy control group, all the patients (with or without pulmonary hypertension) had higher serum MDA concentrations (1.5 +/- 0.1 versus 2.3 +/- 0.1 versus 2.3 +/- 0.1 nmol/mL, ANOVA, P < 0.001) and lower erythrocyte GPX activity (51.3 +/- 3.2 versus 42.2 +/- 2.0 versus 41.3 +/- 2.5 U/g Hb, P = 0.029), whereas SOD (1121.1 +/- 29.0 versus 1032.6 +/- 21.8 versus 1032.7 +/- 36.2 U/g Hb, P = 0.063) and CAT activities (4.9 +/- 0.2 versus 4.6 +/- 0.1 versus 4.7 +/- 0.2 U/g Hb; P= 0.454) were similar. No differences were observed in serum MDA concentrations or activities of GPX, SOD and CAT in erythrocytes between COPD patients with and without pulmonary hypertension.


CONCLUSIONS
The study demonstrates the presence of oxidative/antioxidative imbalance in the systemic circulation in patients with COPD: compared with healthy subjects, COPD patients had higher serum MDA concentrations and lower GPX activity in erythrocytes. The magnitudes of the increase in MDA and reduction in GPX activity were similar in COPD patients with pulmonary hypertension and in those with normal pulmonary artery pressures.
Department of Respiratory Medicine and Tuberculosis, Faculty of Medicine, P.J. Safárik University and L. Pasteur Teaching Hospital, Rastislavova 43, 041 90 Kosice, Slovakia.
Pavol
P
Joppa
Darina
D
Petrásová
Branislav
B
Stancák
Zuzana
Z
Dorková
Ruzena
R
Tkácová
D000368:Aged; D001783:Blood Flow Velocity / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood; D002374:Catalase / Q000097:blood; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D005979:Glutathione Peroxidase / Q000097:blood; D006801:Humans; D006976:Hypertension, Pulmonary / Q000503:physiopathology*; D015227:Lipid Peroxidation / Q000502:physiology; D008168:Lung / Q000503:physiopathology; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D010100:Oxygen / Q000097:blood; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology*; D011669:Pulmonary Wedge Pressure / Q000502:physiology; D012115:Residual Volume / Q000502:physiology; D012907:Smoking / Q000009:adverse effects; D013318:Stroke Volume / Q000502:physiology; D013482:Superoxide Dismutase / Q000097:blood; D013990:Tidal Volume / Q000502:physiology
D002245:Carbon Dioxide; D008315:Malondialdehyde; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D010100:Oxygen