Plasma levels of TIPM-2 in patients with COPD

COPD is a chronic disease of the lung that is associated with abnormal chronic inflammation in the airways and extensive tissue remodeling. Among the different types of enzymes implicated in lung tissue remodeling are matrix metalloproteinases (MMPs) and their specific tissue inhibitors of metalloproteinases (TIMP). The aim of the current study was to elucidate the possible role of plasma levels of TIMP-2 as biomarker of COPD. We assessed with ELISA method TIMP-2 levels in 60 patients and 20 controls. The plasma TIMP-2 levels were significantly higher in patients than in controls (1.81±0.54 vs. 2.23±0.80 ng/ml, p=0.006). The Receiver Operating Characteristics (ROC) curve produced area under the curve (AUC) of 0.707 with 95% CI of 0.583-0.831 (p=0.006). The cutoff value of 2.00 ng/ml determined sensitivity of 0.767 and specificity of 0.600: 76.6% of the patients and 40.0% of the controls had lower than 2.00 ng/ml plasma TIMP-2. The levels of TIMP-2 did not differ between patients non-smokers and smokers, but correlated significantly with the smoking index of the latter (packs/yearRho=0.326, p=0.027). TIMP-2 levels tended to correlate negatively to the serum MMP-3 levels (Rho= -0.436, p=0.180), but not to the plasma levels of MMP-2 (Rho=0.48, p=0.720) in the patients with COPD. The MMP-2/TIMP2 ratio was significantly higher in patients than in controls (p=0.012) and correlated negatively with smoking index (Rho= -0.317, p=0.034). In conclusion, our results suggest that the plasma TIMP-2 and MMP-2/TIMP-2 are increased in patients with COPD and correlates with the cigarette use of smokers, but it can not be applied as valuable biomarker for severity of the disease. This work was supported by COST BM1201 and project 4/2014 of MF, TrU.