Impact of One Versus Two Consecutive Doses of Endothelial Cells (EPCs) and EPCs-Derived Condition Medium on Protecting Myocardium from Acute Ischemia-Reperfusion Injury in Rat

This study tested the impact of single dose and two doses of endothelial progenitor cells (EPCs) and EPCs-derived condition medium (CM) on protecting the left-ventricular myocardium (LVM) from acute ischemia-reperfusion (IR) injury. In vitro study showed EPCs and CM had comparably higher capacity for enhancement of angiogenesis as compared with the controls (all P < .001). Adult-male SD rats ( n = 36) were equally categorized into groups 1 (sham-operated control), 2 (IR+vehicle), 3 [IR+EPCs/1.2 × 10 6 /intravenous administration at 3 h after IR procedure), 4 (IR+EPCs/1.2 × 10 6 /at 3 h/24 h after IR), 5 (IR+CM/3.0cc/intravenous administration at 3 h after IR), 6 (IR+EPCs/3.0cc/at 3h/24 h after IR), and euthanized by day 3 after IR. The left-ventricular-ejection-fraction, protein and cellular expressions of endothelial-cell markers (CD31/vWF), small vessel number and protein expression of mitochondrial (mitochondrial-cytochrome-C) integrity were highest in group 1, lowest in group 2, significantly higher in group 4 than in groups 3/5/6 and significantly higher in groups 3/6 than in group 5 but they showed no differences in groups3/6, whereas the protein expressions of apoptotic (cleaved-caspase 3/cleaved-PARP), fibrotic (Smad3/TGF-ß), mitochondrial-damaged (cytosolic-cytochrome-C), heart-failed/pressure-overload (BNP), oxidative-stress (p47phox/NOX-1/NOX-2/oxidized protein), and autophagic (LCB3-II/LCB3-I) biomarkers and fibrotic/collagen-deposition areas exhibited an opposite pattern to endothelial-cell markers (all P < .0001). The protein expressions of angiogenesis (VEGF/SDF-1α/CXCR4/HIF-1α) were lowest in group 1, highest in group 4, significantly higher in groups 3/6 than in groups 2/5, significantly higher in group 5 than in group 2, but they showed no difference between groups 3/6 (all P < .0001). These results demonstrate that two consecutive doses of EPC/CM were superior to just one at protecting LVM against IR injury.