MMP9 and chronic obstructive pulmonary disease: Contrastingly, the concentration of TIMP-1 and the MMP-9/TIMP-1-ratio were similar in non-COPD and COPD; 316 (220–490) vs. 304 (227–430) ng/ml, p = 0.252 and 1.36 (0.85–2.09) vs. 1.50 (0.83–2.32), p = 0.168.