Impaired Colony-Forming Capacity of Circulating Endothelial Progenitor Cells in Patients with Emphysema

Impaired Colony-Forming Capacity of Circulating Endothelial Progenitor Cells in Patients with Emphysema

EUN-KYUNG KIM,¹ JI-HYUN LEE,¹ HYE-CHEOL JEONG,¹ DOYEON OH,¹ SEONG-GYU HWANG,¹ YONG-WOOK CHO,¹ SEON-JU LEE,² YEON-MOK OH^3,4 and SANG-DO LEE^3,4

¹Department of Internal Medicine, CHA Bundang Medical Center, College of Medicine, CHA University, Seongnam, Korea
²Institute for Clinical Research, College of Medicine, CHA University, Seongnam, Korea
³Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Asan Medical Center, College of Medicine University of Ulsan, Seoul, Korea
⁴Clinical Research Center for Chronic Obstructive Airway Diseases, Seoul, Korea

Chronic obstructive pulmonary disease (COPD) is classified into emphysema and chronic bronchitis, which are thought to result from different pathophysiological pathways. Smoking-induced lung parenchymal destruction and inadequate repair are involved in the pathogenesis of emphysema. In addition, decreased expression of vascular endothelial growth factor and increased endothelial cell apoptosis in the lung may participate in emphysema pathogenesis. As stem cells, circulating endothelial progenitor cells (EPCs) may play a key role in the maintenance of vascular integrity by replacing and repairing the damaged endothelial cells in the tissues. To determine whether the lack of appropriate repair by circulating EPCs in cases of smoking-induced endothelial cell injury participates in emphysema pathogenesis, we determined the association between the colony-forming or migratory capacity of circulating EPCs and the presence of emphysema in 51 patients with COPD. The patients were divided into emphysema (n = 23) and non-emphysema groups (n = 28) based on high-resolution computed tomography. Twenty-two smokers with normal lung function and 14 normal non-smokers served as controls. Circulating EPCs isolated from patients with emphysema showed significantly lower colony-forming units (CFUs) than those from patients with non-emphysema group, smokers with normal lung function, and normal non-smokers. EPCs from patients with emphysema showed significantly lower migratory capacity than those from normal non-smoking controls (p < 0.05). On multivariate analysis, the EPC-CFU was independently associated with emphysema (OR 0.944, 95% CI = 0.903-0.987, p = 0.011). Thus, impaired functions of circulating EPCs may contribute to the development of emphysema.

keywords —— chronic obstructive pulmonary disease; colony-forming units; emphysema; endothelial progenitor cell; high-resolution computed tomography

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Tohoku J. Exp. Med., 2012, 227, 321-331

Correspondence: Sang-Do Lee, M.D., Ph.D., Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, 388-1 Poongnab-dong, Songpa-gu, Seoul 138-736, Korea.

e-mail: sdlee@amc.seoul.kr