It has been suggested that matrix-metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of metalloproteinases (TIMPs) play a major role in the regulation of myocardial remodeling. Myocardial extracellular matrix (ECM) is highly susceptible to ischemic injury in acute myocardial infarction (AMI).We measured serum levels of TIMP-1 in the early hours of AMI to study the kinetics of these enzymes in an early ischemic phase.TIMP-1 was measured in 25 patients with AMI and 116 healthy controls. Blood samples were obtained during the first 12 hours after hospital admission. Left ventricular function (LVF) and hemodynamic data were collected during coronary intervention.TIMP-1 was significantly elevated in patients with AMI within the first hours compared to controls (P<0.05). No significant difference was observed between patients with preserved LVF and with impaired LVF. Elevated TIMP-1 levels did not correlate with increased levels of CK or CK-MB band during the first hours after AMI.Increased TIMP-1 can be detected within 12 hours in patients with AMI, suggesting early onset of remodeling. Elevation of TIMP-1 may be a surrogate marker for increased ECM-turnover. The prognostic relevance needs to be proved in long-term studies.