In one study, hypoadiponectinemia in ADIPOQ gene-knockout mice was associated with emphysema-like changes in the lungs and extrapulmonary features including systemic inflammation, obesity, and osteoporosis [14], while another study reported the opposite effect in which mice deficient in adiponectin were protected from emphysema when they were exposed to cigarette smoke [39]. This evidence concerns the gene ADIPOQ and pulmonary emphysema.