Sustained Effects of Hypertonic Saline on Mucociliary Clearance in Subjects With Chronic Bronchitis

The purpose of this research study is to examine the effects of two weeks of daily dosing of inhaled salt water mist (hypertonic saline - HS) on actual measurements of mucociliary and cough clearance in patients with the chronic bronchitis type of Chronic Obstructive Pulmonary Disease (COPD. Defective mucociliary clearance (MCC) is central to the development and/or worsening of several kinds of lung diseases, including COPD/chronic bronchitis (CB), cystic fibrosis (CF), and bronchiectasis. In each case, defective MCC leads to the development of lung infections and damage to the airways from ongoing inflammation caused by a person's inability to clear mucus from the lungs. The investigators' previous studies have shown that the administration of inhaled HS (hypertonic saline) not only acutely accelerates MCC in CF, but also that repetitive use "resets" the baseline rate of MCC within 2 weeks. It is likely that the sustained effect of HS on MCC was responsible for the \~60% reduction in the frequency of pulmonary disease exacerbations, reduced antibiotic use and improved lung function in a long-term study of HS in CF volunteers. As a result, HS has now become a standard therapy for CF lung disease and its success raises optimism that similar benefits might occur in patients with CB. In this study the investigators will use mildly radioactive particles, technetium bound to sulfur colloid, to measure and compare the sustained effects on mucus clearance of two weeks of daily dosing of 7% hypertonic saline versus a low salt control treatment for subjects with CB. We will also be collecting sputum and breath condensation to analyze for protein and inflammatory changes that might occur with exacerbations. Our long term goals are to improve our understanding of MCC in health and disease and to develop better therapies that support and/or restore MCC in patients with these diseases to reduce lung infections.