PDGFBB increases myocardial production of VEGF:: Shift in VEGF mRNA splice variants after direct injection of bFGF, PDGFBB, and PDGFAB

Background. Vascular endothelial growth factor (VEGF) plays an important role in angiogenesis. We hypothesized that a combination of recombinant angiogenic proteins might induce myocardial VEGF production and cause a shift in the mRNA signal produced. Materials and methods. The left ventricles of New Zealand white rabbits were injected with 500 muL, of saline, basic fibroblast growth factor (bFGF), platelet-derived growth factor-AB (PDGF(AB)), platelet-derived growth factor-BB (PDGF(BB)), bFGF + PDGF(AB), or bFGF + PDGF(BB). Myocardial VEGF production was analyzed by ELISA while mRNA splice variants were analyzed by RT-PCR 3 and 7 days after injection. Results. PDGF(BB) alone caused the most pronounced induction of VEGF. Three days after injection the induction of VEGF by PDGF(BB) was significant compared to all treatment groups, except the bFGF + PDGF(BB) group. Induction of VEGF by PDGF(BB) was associated with a decrease in mRNA production of VEGF(121) within the myocardium. Conclusions. Injection of PDGF(BB) induces significant production of VEGF within the myocardium. This induction of VEGF production is associated with a shift toward other, less soluble forms of VEGF. These findings may allow more precise regulation of the myocardial response to therapeutic angiogenesis. (C) 2002 Elsevier Science (USA).