CFTR and chronic obstructive pulmonary disease: Thus, CFTR decrements observed in our SHS studies may be highly relevant to the pathogenesis of airways diseases with decreased MCC including, COPD-related chronic bronchitis, a major COPD phenotype that we have previously shown to be causally associated with acquired defects in CFTR expression and function [4, 9] Moreover, the recent emergence of small molecule drugs such as Ivacaftor that can increase CFTR activity, including in patients with normal CFTR genetics, has opened new avenues of potential treatments for respiratory illnesses like COPD -related chronic bronchitis [50].