Elevated serum markers of collagen degradation in patients with mild to moderate dilated cardiomyopathy

Background and aims Left ventricular (LV) dilation and myocardial remodelling are hallmarks of heart failure in idiopathic dilated cardiomyopathy (DCM). Interstitial collagen is essential for LV integrity and function while degradation of collagen by collagenases, especially matrix‐metalloproteinases (MMPs), are suggested to contribute to ventricular dilation. In the present study, serological markers of collagen metabolism were investigated. Methods and results Serum levels of MMP‐1 and its inhibitor (TIMP‐1), the markers for collagen degradation type I (collagen carboxyterminal telopeptide (ICTP)) and synthesis (carboxyterminal propeptide of type I procollagen (PICP)) were quantified by ELISA and RIA of 43 patients with DCM and 47 age‐matched control subjects. Free MMP‐1 serum concentration was significantly increased in the DCM group (5.29±0.83 vs. 2.22±0.29 ng/ml; P‐0.01) as well as the free TIMP‐1 concentration (206.54±12.65 vs. 181.44±8.55 ng/ml; P‐0.05). The free MMP‐1/TIMP‐1‐ratio was higher in DCM than in the control group (0.030±0.005 vs. 0.012±0.001; P‐0.01). ICTP was significantly increased (7.60±1.21 vs. 3.44±0.19 μg/l; P