Background: Vascular endothelial growth factor (VEGF) is an important active protein for the induction of angiogenesis and improvement in cardiac function after myocardial ischemia; however, the lack of a delivery system targeted to the injured myocardium reduces the local therapeutic efficacy of VEGF and increases its possible adverse effects.
Methods and results: We produced a fusion protein (CBD-VEGF) consisting of VEGF and a collagen-binding domain (CBD). The fusion protein specifically bound to type I collagen in vitro. In addition, CBD-VEGF promoted human umbilical vein endothelial cell proliferation after binding to collagen, which indicates that it retained both growth factor activity and collagen-binding ability. When implanted subcutaneously in rats, collagen membranes loaded with CBD-VEGF were significantly vascularized. After it was injected into rats with acute myocardial infarction, CBD-VEGF was largely retained in the cardiac extracellular matrix, in which collagen I was rich. Four weeks after VEGF or CBD-VEGF was injected into the infarct border zone, cardiac function detected by echocardiography and hemodynamics was preserved in the CBD-VEGF group. Administration of CBD-VEGF also induced reduction of scar size, whereas native VEGF did not have these effects. In addition, a significant increase in the number of capillary vessels in infarcted hearts was found in the CBD-VEGF group.
Conclusions: The injection of CBD-VEGF improved cardiac function in rats with induced acute myocardial infarction. This could potentially provide a new treatment option for myocardial infarction.