The purpose of this study is to investigate the role of the pulmonary vasculature in the development and progression of chronic obstructive pulmonary disease (COPD). To accomplish this, an inhaled prostacyclin (iloprost) will be given to patients with COPD and changes in oxidative stress and lung volumes during exercise will be measured.

Chronic obstructive pulmonary disease (COPD), the 3rd leading cause of death in the US, is a progressive disorder for which new treatments are urgently needed, as existing therapies are focused primarily on symptom relief. Oxidative stress, in part arising from inducible nitric oxide synthase (iNOS) released by the pulmonary vasculature, is critical for the development and progression of COPD; a treatment strategy focused on the pulmonary vasculature is hypothesized to be beneficial in COPD patients. This will be studied with the use of an inhaled prostacyclin analogue, iloprost, which has been approved for pulmonary hypertension and investigated in small studies of COPD patients. Potential mechanisms include reductions in dynamic hyperinflation during exercise in COPD patients or improvements in oxidative stress

Inclusion Criteria:

• 40 years old or older
• Physician diagnosis of chronic obstructive pulmonary disease
• 10 or more pack-year smoking history
• FEV1/FVC <0.70
• FEV1 35-80% of predicted

Exclusion Criteria:

• Acute exacerbation of COPD within the last 30 days
• Pregnant or breast-feeding
• Contraindications to cardiopulmonary exercise testing
• Known intolerance or allergy to iloprost
• On oral corticosteroids (may be included if off for 7 days prior to testing)
• Supplemental oxygen need
• Known inflammatory disease other than COPD
• Active solid organ/hematologic malignancy