Conditions: Tobacco Abuse Smoke
Keywords: smokers inhaled corticosteroids brachial flow airway blood flow albuterol spirometry endothelial dysfunction
Allocation: RANDOMIZED | Intervention model: CROSSOVER
Enrollment: 32
Healthy volunteers: yes

Brief summary:
The hypothesis underlying the proposed study is that the blunted endothelium-dependent vasodilation seen in the airway of current smokers is also present in the brachial artery, and that the same inhaled corticosteroid (ICS) treatment regime that reversed endothelial function in the airway of current smokers will also restore endothelium-dependent relaxation in the brachial artery. Non-smokers will be used as controls and will not receive any intervention or treatment.

Detailed description:
Cigarette smoking can lead to systemic endothelial dysfunction. Since the airway circulation is exposed to a high concentration of cigarette smoke constituents, we reasoned that airway vascular endothelial dysfunction could be present in healthy smokers without systemic endothelial dysfunction.

The purpose of this study was to compare airway and systemic endothelial function and measure markers of systemic inflammation in lung-healthy current smokers. Since endothelial dysfunction in smokers has been related to systemic inflammation, we also investigated its response to an inhaled glucocorticosteroid (ICS).

Vascular endothelial function was assessed in the airway by the airway blood-flow (Qaw) response to inhaled albuterol (ΔQaw) and in the extrapulmonary circulation by brachial arterial flow-mediated vasodilation (FMD). Venous blood was collected for C-reactive protein and IL-6.

Qaw was measured with a noninvasive inhaled soluble gas uptake technique. The uptake of the gas from the anatomical deadspace reflecting airways perfused by the airway circulation was quantitated.

Qaw was express as μL/min normalized for anatomical deadspace: μL/min/mL.

Arms:
arm 1: The current smokers will be given a 3-week treatment course of inhaled fluticasone (220 ug fluticasone twice a day administered as a MDI) . The subjects and the investigators will be blinded to the random choice of inhaler. arm 2: The current smokers will be given a 3-week treatment course of inhaled placebo MDI. The subjects and the investigators will be blinded to the random choice of inhaler. arm 3: The healthy non-smokers will have only visit 1 and no intervention.

Interventions: intervention 1: Fluticasone intervention 2: Placebo
Intervention descriptions: intervention 1: 220 ug twice a day for 3 weeks intervention 2: Placebo for 3 weeks

Protocol document: