Targeted disruption of the Fgf2 gene does not affect vascular growth in the mouse ischemic hindlimb

Ischemic revascularization involves extensive structural adaptation of the vasculature, including both angiogenesis and arteriogenesis. Previous studies suggest that fibroblast growth factor (FGF)-2 participates in both angiogenesis and arteriogenesis. Despite this, the specific role of endogenous FGF-2 in vascular adaptation during ischemic revascularization is unknown. Therefore, we used femoral artery ligation in Fgf2^+/+ and Fgf2^-/- mice to test the hypothesis that endogenous FGF-2 is an important regulator of angiogenesis and arteriogenesis in the setting of hindlimb ischemia. Femoral ligation increased capillary and arteriole density in the ischemic calf in both Fgf2^+/+ and Fgf2^-/- mice. The level of angiographically visible arteries in the thigh was increased in the ischemic hindlimb in all mice, and no significant differences were observed between Fgf2^+/+ and Fgf2^-/- mice. Additionally, limb perfusion progressively improved to peak values at day 35 postsurgery in both genotypes. Given the equivalent responses observed in Fgf2^+/+ and Fgf2^-/- mice, we demonstrate that endogenous FGF-2 is not required for revascularization in the setting of peripheral ischemia. Vascular adaptation, including both angiogenesis and arteriogenesis, was not affected by the absence of FGF-2 in this model.