ObjectiveTo investigate the expression of SIR2-related enzyme 1 (SIRT1) in serum of patients with chronic obstructive pulmonary disease (COPD) and its clinical significance.MethodsForty patients with acute exacerbation of COPD (acute-COPD group) and 30 patients with stable COPD (stable-COPD group) were selected as study groups. Twenty healthy subjects were recruited as a control group. Serum SIRT1, nuclear factor (NF) -κB, and matrix metalloproteinases (MMP) -9 levels were detected by enzyme-linked immunosorbent assay and Western blot.ResultsCompared with the control group, the FEV1%pred and FEV1/FVC were significantly decreased in the acute COPD patients and the stable COPD patients (P<0.05). Compared with the stable-COPD group, FEV1%pred and FEV1/FVC were significantly decreased in the acute-COPD group (P<0.05). Compared with control group, the serum SIRT1 in the stable-COPD group and the acute-COPD group were significantly decreased, while NF-κB and MMP-9 were significantly increased (P<0.05). Compared with the stable-COPD group, SIRT1 in the acute-COPD group was significantly decreased, while NF-κB and MMP-9 were significantly increased (P<0.05). SIRT1 were positively correlated with FEV1%pred (P<0.05) and FEV1/FVC (P<0.05) in the COPD patients by Pearson linear correlation analysis. SIRT1 was negatively correlated with NF-κB (P<0.05) and MMP-9 (P<0.05).ConclusionIn COPD patients, decreased levels of serum SIRT1 is associates with decreased lung function, which may be used as a potential biomarker of COPD.