Pretreatment with intracoronary mimosine improves postischemic myocardial functional recovery

Background: Cytoprotective growth factors such as vascular endothelial growth factor (VEGF) play important roles in myocardial protection from ischemia/reperfusion (I/R). Accumulating evidence suggests that the hypoxia-inducible factor 1 (HIF-1) pathway is a key regulator of VEGF production in the setting of I/R. The prolyl hydroxylase inhibitor mimosine can increase VEGF production through the HIF-1 pathway. We hypothesized that infusion of preischemic intracoronary mimosine would improve myocardial functional recovery after I/R. Methods: Isolated male rat hearts were subjected to 15 minutes of equilibration, 25 minutes of ischemia, and 40 minutes of reperfusion. Immediately prior to ischemia, ischemic hearts received intracoronary infusions of vehicle or solutions of 0.3, 3, or 30 μM mimosine. Myocardial function was recorded throughout the experiments. Functional data were analyzed with two-way analysis of variance adjusted with the Bonferroni correction. Results: Preischemic myocardial function was equivalent. All hearts had significant reductions in function at the beginning of reperfusion. Hearts treated with 0.3 or 3 μM mimosine infusions exhibited greater recovery of left ventricular developed pressure compared to vehicle. The maximal positive value of the first derivative of pressure (+dP/dt) was greater in hearts treated with 0.3 μM mimosine compared to hearts treated with vehicle. No differences were observed in recovery of end-diastolic pressure or the maximal negative value of the first derivative of pressure (-dP/dt). Conclusion: Preischemic intracoronary mimosine infusion improves myocardial functional recovery after I/R.