[American Thoracic Society American Thoracic Society 2012 International Conference, May 18-23, 2012 • San Francisco, California - ()] C17. CELLULAR AND MOLECULAR SIGNALING IN THE PULMONARY ENDOTHELIUM REGULATING PROLIFERATION AND PROGRAMMED CELL DEATH - Endothelial Colony Forming Cells Are Senescent And Dysfunctional In Cigarette Smokers And Patients With COPD; Evidence Of Endothelial Dysfunction Due To Cigarette Smoking-Oxidative Stress