Intrapericardial basic fibroblast growth factor induces myocardial angiogenesis in a rabbit model of chronic ischemia

The objective of this study was to determine whether basic fibroblast growth factor (bFGF), a known angiogenic factor, can promote new vessel growth when infused within the pericardial space in a model of chronic myocardial ischemia. Intravenous angiotensin II (AII) was infused to induce left ventricular hypertrophy and concomitant ischemia in New Zealand white rabbits. Basic FGF was infused into the intrapericardial space with an osmotic pump. Animals were assigned to one of four groups: group 1 received intrapericardial bFGF and intravenous AII, group 2 received intrapericardial bFGF and intravenous saline solution, group 3 received intrapericardial albumin and intravenous AII, and group 4 received intravenous AII only. Epicardial angiogenesis was graded histologically on a scale of 0 to 2. Animals receiving intravenous administration of AII displayed left ventricular hypertrophy that disproportionately affected the interventricular septum with a wall thickness of 5.62 +/- 1.00 mm versus 3.98 +/- 0.61 mm in the AII group and the saline solution control group, respectively (p < 0.005). A highly localized angiogenic effect of bFGF was observed. The mean angiogenesis scores were 1.9, 1.4, 1.3, and 0.2 (p < 0.001) with an angiogenesis score of 2 (marked increase in vascularity) noted in 86%, 40%, 43%, and 0% of hearts in groups 1 through 4, respectively. We conclude that intrapericardial bFGF enhances new epicardial small-vessel growth in a rabbit model; furthermore this effect is enhanced in the presence of left ventricular hypertrophy.