CFTR and pulmonary emphysema: A second link between CFTR dysfunction and emphysema formation was suggested by recent studies demonstrating i) that cigarette smoke exposure reduces CFTR expression and function [15,16,57] in vitro and in vivo; ii) that CFTR protein levels correlate inversely with ceramide accumulation and emphysema severity in lungs from COPD patients [17]; and iii) that CFTR controls cigarette-smoke induced apoptosis and autophagy in mice [58].