Due to the ubiquitous use of ICS in the treatment of COPD in 2012, it was hard to find the study population.

In the present study, the investigators wish to address the effect of a glucocorticoid/long-acting beta-agonist preparation on endothelial function in COPD patients who do not currently smoke (ex-smokers) by measuring endothelium-dependent (albuterol response) and endothelium-independent (NTG response) vasodilation in the bronchial artery, reflecting endothelium-dependent and endothelium-independent vasodilation (drug-induced increase in Qaw, ΔQaw). With this approach the investigators will test the hypothesis that in stable ICS-naïve COPD patients, endothelium-dependent vasodilation is restored with a glucocorticoid/long-acting beta-agonist preparation, presumably resulting from the glucocorticoid component.

To test the premise and to characterize the time dependence of the responses, the investigators propose the following two aims:

1. To determine the effect of a medium dose glucocorticoid/long-acting beta-agonist preparation (250 μg fluticasone plus 50 μg salmeterol) administered for 3 weeks on inhaled albuterol and sub-lingual NTG induced vasodilation in the bronchial artery, as assessed by ΔQaw in stable glucocorticoid-naïve COPD patients, and to re-assess the responses after a 3 week glucocorticoid/long-acting beta-agonist washout period.
2. To determine inhaled albuterol and sub-lingual NTG-induced vasodilation (ΔQaw) before, and 30 min and 120 min after a single medium dose of an ICS (220 μg fluticasone) in stable glucocorticoid- naïve COPD patients.

For both aims, the protocol design will be placebo-controlled and double-blind. For the second aim, only fluticasone pretreatment will be possible because the salmeterol component of the fluticasone/salmeterol combination preparation could influence albuterol responsiveness irrespective of any glucocorticoid effect. The timing of the endothelial function measurements in the long-term glucocorticoid/long-acting beta-agonist protocol and single dose ICS protocol is based on the past experience with ICS on airway vascular function. Single dose effects were seen within 15-30 min and waned by 90 min (25,26), while long-term treatment effects were no longer seen 3 weeks after ICS withdrawal (16).

Inclusion Criteria:

• Smoking history of at least 10 pack-years and to have quit smoking at least 1 year before the study. -Diagnosis of COPD
• Post-bronchodilator FEV1 of less than 75% of predicted and FEV1/FVC ratio less than 0.7 (GOLD stage ≥2).
• At entry into the study, the subjects will have to be clinically stable; they will be allowed to use short-acting and long-acting β2 - adrenergic agonists and cholinergic antagonists as their usual airway medication.

Exclusion Criteria:

• Women of childbearing potential who do not use accepted birth control measures; pregnant and breast feeding women.
• Use of cardiovascular medications that cannot be held on the study days
• Use of oral airway medications or anti-inflammatory agents
• Subjects with known beta-adrenergic agonist or NTG intolerance
• Acute respiratory infection within four weeks prior to the study
• A body mass index > 30