OBJECTIVE: The effects of cell transplantation on the ischemic failing heart 
have already been documented. However, the area in and around infarct regions is 
not a good environment for cells to survive in because they are exposed to poor 
conditions in which certain requirements cannot be adequately supplied. We 
therefore designed a study to investigate the efficacy of prevascularization in 
ischemic regions before cell transplantation.
METHODS: Rats with myocardial infarction were randomized into 4 groups: 11 rats 
received a culture medium injection to the left ventricular wall (control 
group), 11 received fetal cardiomyocyte transplantation (TX group), 11 received 
gelatin hydrogel microspheres incorporating basic fibroblast growth factor (FGF 
group), and 11 received basic fibroblast growth factor pretreatment 
sequentially, followed by cardiomyocyte transplantation (FGF-TX group). Four 
weeks later, left ventricular function was assessed by means of echocardiography 
and cardiac catheterization.
RESULTS: In the FGF and FGF-TX groups neovascularization was found in the scar 
tissue 1 week later. The TX, FGF, and FGF-TX groups showed better fractional 
shortening than the control group (TX, FGF, FGF-TX, and control: 28% +/- 4.4%, 
24% +/- 8.6%, 27% +/- 7.3%, and 17% +/- 4.6%, respectively; P <.01). Left 
ventricular maximum time-varying elastance was higher in the FGF-TX group than 
in the TX and FGF groups (FGF-TX, TX, and FGF: 0.52 +/- 0.23, 0.30 +/- 0.08, and 
0.27 +/- 0.20 mm Hg/microL, respectively; P <.01). Histologically, more 
transplanted cells survived in the FGF-TX group than in the TX group.
CONCLUSIONS: Prevascularization with basic fibroblast growth factor-incorporated 
microspheres enhances the benefits of cardiomyocyte transplantation. We expect 
that this system will contribute to regeneration medicine through its extensive 
application to other growth factors.