ObjectiveTo explore the serum concentrations of complement C1q tumor necrosis factor related protein 5 (CTRP5) in patients with acute exacerbations and stable stage of chronic obstructive pulmonary disease (COPD), and analyze the correlation of CTRP5 with high sensitivity C-reactive protein (hs-CRP) and FEV1/FVC and FEV1%pred.MethodsThirty hospitalized patients with acute exacerbation of COPD and 30 outpatients with stable COPD according with diagnostic criteria and inclusive criteria were sampled successively. At the same time 30 healthy volunteers were selected as normal control. All subjects were measured the concentrations of CTRP5 and hs-CRP in serum and lung function test was performed.ResultsThe serum CTRP5 and hs-CRP concentrations of the acute exacerbation group was higher than those in the stable group and the control group. The serum CTRP5 and hs-CRP concentrations of the stable group was also higher than those of the control group. The FEV1/FVC of the acute exacerbation group was lower than those of the stable group and the control group; and the FEV1/FVC of the stable group was lower than that of the control group. The FEV1%pred of three groups by analysis indicated the difference was statistically significant. Further pairwise comparisons demonstrated that the FEV1%pred of two COPD groups were lower than that of the control group but the FEV1%pred of the acute exacerbation group and stable group was not significantly different. The correlation analysis of the acute exacerbation group and the stable group demonstrated that the levels of serum CTRP5 and hs-CRP were postively correlated and the level of serum CTRP5 was negatively correlated with FEV1/FVC and FEV1%pred.ConclusionsThe level of CTRP5 in serum of COPD patients is increased. No matter in acute exacerbation or stable phase, the level of serum CTRP5 is positively correlated with hs-CRP and negatively correlated with FEV1/FVC and FEV1%pred, which suggests that CTRP5 is involved in the pathogenesis of COPD but the exact mechanism needs further study.