Intracoronary administration of AdvFGF-5 (fibroblast growth factor-5) ameliorates left ventricular dysfunction and prevents myocyte loss in swine with developing collaterals and ischemic cardiomyopathy

Background - Fibroblast growth factor (AdvFGF-5) improves regional function by stimulating myocyte hypertrophy without increasing myocardial perfusion in swine with hibernating myocardium. We performed the present study to determine whether AdvFGF-5 could prevent the progression of LV dysfunction in swine with ischemic cardiomyopathy. Methods and Results - Swine were chronically instrumented with LAD and LCX stenoses to produce viable dysfunctional myocardium and studied 1 month after instrumentation in the closed-chest sedated state. Flow and regional function before and 30 days after intracoronary AdvFGF-5 (2 x 10(12) vp, n = 9) were compared with animals receiving intracoronary AdvEGFP (2 x 10(12) vp, n = 6). Histological analysis was performed to quantify myocyte size, myocyte nuclear density, apoptosis (TUNEL), and the frequency of myocytes in the proliferative phase of the cell cycle (Ki-67 staining). LAD wall-thickening (27 +/- 3 to 46 +/- 6%, P < 0.05) and EF (39 +/- 4 to 56 +/- 3%, P < 0.05) increased after AdvFGF-5. AdvFGF-5 increased maximal perfusion during adenosine vasodilation despite no differences in baseline flow or stenosis severity. After AdvFGF-5, TUNEL-positive myocytes decreased 6-fold and Ki-67 positive myocyte nuclei increased 2-fold. As a result, AdvFGF-5 produced a marked increase in myocyte nuclear density (957 +/- 54 to 1447 +/- 40 nuclei/mm(2), P < 0.05). Conclusion - These data indicate that AdvFGF-5 increases regional function and maximal perfusion distal to stenotic arteries when administered before the development of collaterals. This was associated with a reduction in myocyte apoptosis, an increase in Ki-67-positive myocytes, and an increase in myocyte number. Thus, AdvFGF-5 offers a potential therapeutic approach to prevent the progression of ischemic cardiomyopathy and heart failure.