RETRACTED: Protection against myocardial ischemia-reperfusion injury by the angiogenic masterswitch protein PR 39 gene therapy: The roles of HIF1α stabilization and FGFR1 signaling (Retracted Article)

PR-39, a proline-arginine-rich angiogenic response peptide, has been implicated in myocardial ischemic reperfusion injury. The present study examined the cardioprotective abilities of PR39 gene therapy. Male C5713146 mice were randomized to intramyocardial injecton of 10(9) p.f.u. adenovirus encoding PR39 (PR39), FGFR1 dominant negative signaling construct (FGFR1-dn), empty vector (EV), or PR39 adenovirus plus 4 mu g of plasmid endcoding a HIF1 alpha dominant negative construct (PR39 + HIF1 alpha-dn). Seven days later, hearts were subjected to 20 min of ischemia (1) and 2 h. reperfusion (R) ex vivo and aortic and coronary flow, left ventricular developed pressure (LVDP), and LVdp/dt were measured. Myocardial infarct (MI) size and cardiomyocyte apoptosis were measured by TTC staining and TUNEL, respectively. PR39 expression was robust up to 14 days after gene transfer and was absent after EV and FGFR1-dn. Hemodynamics showed no differences at baseline, and heart rate remained unchanged in all groups throughout the experiment. After I-R, hemodynamics remained unchanged in PR39 hearts, but deteriorated significantly in the other groups, except for aortic flow, which remained significantly higher in FGFR1-dn than in EV and PR39 + HIF1 alpha-dn (p < 0.05), although it was lower than in PR39 (p < 0.05). MI was 8.7 +/- 0.9 % in PR39, 23.8 +/- 1.1 % in FGFR1-dn, 29.9 +/- 2.2% in EV, and 30.8 +/- 2.7 % in PR39 + HIF1 alpha-dn (PR39 vs. other groups: p < 0.05; FGFR1-dn vs. EV and PR39 + HIF1 alpha-dn: p < 0.05). In PR39, HIF-1 alpha protein was higher than in FGFR1-dn and EV. Importantly, cotransfection of HlF1 alpha-dn with PR39 completely abolished cardioprotection by PR39. Cardioprotection by PR39 is likely conveyed by protective metabolic and survival responses through HIF1-alpha stabilization and not by angiogenesis, because baseline coronary How was the same in all groups. Abrogation of FGFR1 signaling conveyed an intermediate degree of cardioprotection.