ABSTRACT
Objective To investigate the changing of endothelial progenitor cells and nitric oxide in patients with pulmonary arterial hypertension secondary to chronic obstructive pulmonary disease.Method Mononuclear cells from 20 healthy persons (the control group, n = 20) , COPD patients without PAH (COPD non-PAH group, n =30) and patients with PAH secondary to COPD (COPD and PAH group, n=30) were investigated. Total mononuclear cells were isolated from peripheral blood by Ficoll density gradient centrifugation. EPC number and migration were assayed by colony forming unit-EPCs (CFU-EPCs) assay and modified Boyden chamber assay , respectively. EPC adhesion assay was performed by replanting those on fibronectin-coated dishes , then adherent cells were counted. The concentration of NO was measured with method of nitrate reductase.Result The numbers of CFU and migration, adhesion activity of circulating EPCs in COPD[ (21.9±3. 9)CFU-EPC] and PAH group[ (14. 2 ±3. 5)CFU-EPC] were significantly lower than that in non-COPD group and COPD non-PAH group [ ( 24.9 ±4.1) CFU-EPC ]. It was also observed that a strong negative correlation between the levels of PAH and the numbers of CFU and adhesion, migration activity of circulating EPCs. The NO level in the PAH group [ (43. 6 ±4. 8)ng/ml] was significantly lower than that in control group [ ( 67. 17±4.9 ) ng/ml ] ( P < 0.01). The NO level was positively correlated with number and migration ability of EPCs( r =0. 77,0.71, P <0.01) , but not correlated with adhesion ability.Conclusion The number of CFU and migratory, adhesive activity of EPC in patients withPAH secondary to COPD was significantly decreased. These changes may be associated with low level of plasma NO.