Effects of oxygen free radical metabolism on pulmonary hemodynamics in patients with chronic obstructive pulmonary disease

Abstract：AIM:To investigate the effects of oxygen free radical metabolism on pathogenic mechanism of chronic obstructive pulmonary disease(COPD). METHODS: Biochemistry tests and radioimmunoassay were performed in 39 COPD patients,and the blood levels of malondialdehyde(MDA),superoxide dismutase(SOD),endothelins-1(ET-1),angiotensin-converting enzyme(ACE),and parameters of blood gases and hemodynamics were measured. RESULTS: The level of MDA of COPD patients was higher than that of the controls(group C).In addition,the patients with pulmonary hypertension (group B)had a higher level of MDA than the patients without pulmonary hypertension(group A)(F=25.30,P< 0.01);SOD activity of the group B was much lower than that of the group A and C(F=4.56,P< 0.05),which was significantly decreased in patient pulmonary artery blood compared with in radial artery and peripheral vein blood(F=6.33,P<0.01). The levels of ET-1 and ACE in the group B were clearly higher than those of the group A and C(F=9.251－ 13.96,P< 0.01);the level of ACE in pulmonary artery was higher than that in radial artery and peripheral vein (F=10.95,P< 0.01).The level of MDA in pulmonary artery was positively correlated with mean pulmonary artery pressure(mPAP) and pulmonary resistance index (PVRI) while was negatively correlated with PaO2; the level of ET-1 was positively correlated with mPAP,PVRI and total pulmonary resistance index(TPRI).Multiple regression analysis showed that MDA and ET-1 could influence mPAP as independent factors,and the effect of MDA was larger than that of ET-1. CONCLUSION: There is an increased oxidative stress and decreased anti-oxidative ability in COPD patients.The development of pulmonary hypertension is closely related to the oxygen free radicals induced direct injury of endotheliocyte.