Chronic obstructive pulmonary disease (COPD) is characterized by fixed air flow limitation and progressive decline of lung function\nand punctuated by occasional exacerbations. The disease pathogenesis may involve activation of the bone marrow stimulating\nmobilization and lung-homing of progenitor cells. We investigated the hypothesis that lower circulating numbers of vascular\nendothelial progenitor cells (VEPCs) are a consequence of increased lung-sequestration in COPD. Nonatopic, current or ex smokers\nwith diagnosed COPD and nonatopic, nonsmoking normal controls were enrolled. Blood and induced sputum extracted\nprimitive hemopoietic progenitors (HPCs) and VEPC were enumerated by flow cytometry. Migration and adhesive responses to\nfibronectin were assessed. In sputum, VEPC numbers were significantly greater in COPD compared to normal controls. In blood,\nVEPCs were significantly lower in COPD versus normal controls. There were no differences in HPC levels between the two groups\nin either compartment. Functionally, there was a greater migrational responsiveness of progenitors from COPD subjects to stromal\ncell-derived factor-1alpha (SDF-1
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