Pharmacological Inhibition Of The Triggering Receptor Expressed On Myeloid Cells-1 Limits Reperfusion Injury In A Porcine Model Of Myocardial Infarction

Aims Limitation of ischemia/reperfusion injury is a major therapeutic target after acute myocardial infarction ( AMI). Toll-like receptors are implicated in the inflammatory response that occurs during reperfusion. The triggering receptor expressed on myeloid cells (TREM)-1 acts as an amplifier of the immune response triggered by toll-like receptor engagement. We hypothesized that administration of a TREM-1 inhibitory peptide (LR12) could limit reperfusion injury in a porcine model of AMI.Methods and results AMI was induced in 15 adult minipigs by a closed-chest coronary artery occlusion-reperfusion technique. Animals were randomized to receive LR12 or vehicle before reperfusion (LR12 n = 7, vehicle n = 8), and were monitored during 18 h.AMI altered hemodynamics and cardiac function, as illustrated by a drop of mean arterial pressure, cardiac index, cardiac power index, ejection fraction, and real-time pressure-volume loop-derived parameters. TREM-1 inhibition by LR12 significantly improved these dysfunctions (P < 0.03) and limited infarct size, as assessed by lower creatine phosphokinase and troponin I concentrations (P < 0.005).Pulmonary, renal, and hepatic impairments occurred after AMI and were attenuated by LR12 administration as assessed by a better PaO2 to FiO(2) ratio, a less positive fluid balance, and lower liver enzymes levels (P < 0.05).Conclusion Inhibition of the TREM-1 pathway by a synthetic peptide limited myocardial reperfusion injury in a clinically relevant porcine model of AMI.