Endogenous cytokine antagonists during myocardial ischemia and thrombolytic therapy

We tested the idea that cytokine antagonists are released during acute myocardial ischemia to counteract proinflammatory effects of cytokines. We investigated changes in plasma concentrations of the anticytokine molecules α-melanocyte-stimulating hormone (α-MSH), interleukin-1 receptor antagonist (IL-1 ra), and soluble tumor necrosis factor receptor (sTNFr) in patients with acute myocardial infarction (AMI) or unstable angina (UA). Blood samples were collected at presentation in the coronary care unit, at 3-hour intervals for 24 hours, and daily for 4 days thereafter. There were no significant differences in the concentrations of cytokine antagonists in patients with AMI or UA. However, whereas concentrations of α-MSH were increased in early samples of patients with AMI or UA who were treated with a thrombolytic agent, they were consistently low in untreated patients. IL-1 ra concentrations likewise were greater 3 and 6 hours after treatment in patients who underwent thrombolysis, whereas there was no significant difference in plasma sTNFr between the two groups. We suggest that during myocardial ischemia and thrombolysis anticytokine molecules released from the injured myocardium become available to reduce inflammation caused by cytokines and other mediators of inflammation.