This is relatively easy (one time injection) and cheap (do not need smoke machine/facility) to assess the effects of LiCl on the development of emphysema.26 Nevertheless, future studies using CS exposure model would provide more convincing data regarding the role of Wnt3a and AMPK on airspace enlargement and lung function decline in COPD/emphysema. This evidence concerns the gene WNT3A and chronic obstructive pulmonary disease.