Introduction:
Previous studies evaluating regenerative strategies have focused on administering stem cells to the infarct related artery. Unfortunately, this does not stimulate cardiac regeneration nor prevent myocyte loss in viable remote myocardium that becomes dysfunctional due to LV remodeling.
Hypothesis:
We hypothesized that administrating allogeneic CDCs to the entire heart (global CDC infusion) at the time of reperfusion could improve function, stimulate myocyte regeneration and prevent myocyte loss throughout the LV.
Methods:
Yorkshire swine (n=12) underwent a one hour LAD occlusion. Ejection fraction (EF) decreased from 63 ± 2% at baseline to 44 ± 2% after infarction (p<0.05 vs. baseline). Immediately after reperfusion animals were randomized to allogeneic intracoronary CDCs or vehicle in a blinded fashion (n=6 each). Allogeneic CDCs (20 x 10^6 CDCs, cyclosporine 100 mg/day) were infused into the 3 major coronary distributions without interrupting flow. Four weeks later we assessed myocardial function (echo), myocyte proliferation (Ki67), infarct size (TTC), myocyte nuclear density and cell size in comparison to vehicle.
Results:
After 4 weeks, global CDC infusion increased wall thickening and ejection fraction despite the fact that infarct volume was not different (Table). CDCs stimulated myocyte proliferation (Ki67) in border and remote regions by 3-fold. As a result, myocyte number (nuclear density) increased by 34 % and cell size decreased by 7% in viable infarct border and remote regions.
Conclusion:
Global infusion of allogeneic CDCs immediately after reperfusion 1.) stimulates myocyte regeneration in viable myocardium remote from the infarct and 2.) improves regional and global LV function without altering infarct size. Thus, treating viable remote myocardium as well as the infarct related artery with allogeneic CDCs may afford a widely available approach to reverse LV dysfunction in patients with acute myocardial infarction.
Correlation of ejection fraction and infarct size estimated from the total CK released in patients with acute myocardial infarction.
