MMP9 and chronic obstructive pulmonary disease: Those with COPD showed significantly higher levels of the following: inflammatory markers IL-6 (COPD: 1.38±1.38 pg/mL vs healthy volunteers [HVs]: 0.58±0.66 pg/mL, p=0.018) and hsCRP (COPD: 6.42±7.68 mg/L vs HV: 2.49±2.84 mg/L, p=0.002); connective tissue markers MMP-9 (COPD: 121±72 ng/mL vs HV: 50±19 ng/mL, p<0.001); lung tissue marker SPD (COPD: 16.9±12.7 ng/mL vs HV: 9.13±5.41 ng/mL, p=0.001); and cardiac markers NT-proBNP (COPD: 603±839 pg/mL vs HV: 198±165 pg/mL, p=0.001) and hsTrop I (COPD: 2.27±1.90 pg/mL vs HV: 0.92±0.49 pg/mL, p<0.001).