SIRT1 and pulmonary emphysema: It has been reported that expression levels of sirtuin 1 (SIRT1), a gene related to longevity, are lower in the lungs of patients with COPD39, and that SIRT1 ablation and overexpression aggravated and ameliorated, respectively, pulmonary emphysema induced by tobacco smoke in mice40, while SIRT1 levels diminished in the lungs of the triple n/i/eNOSs−/− mice.