Ventricular expression of basic fibroblast growth factor gene after orthotopic cardiac transplantation

We studied the ventricular expression of basic fibroblast growth factor (bFGF) at the mRNA level in normal and transplanted human hearts as a direct measure of local bFGF gene expression. By Northern blot hybridization with a human bFGF cDNA probe, mRNA transcripts 7.5, 3.5, and 2.0 kb for bFGF were detected in both normal and transplanted hearts. Densitometric analysis of the transcripts after normalization for RNA loading revealed a 2-fold increase in the transplanted compared with the normal hearts. Slot blot hybridization of the ventricular RNA showed a significant increase in bFGF mRNA level in the transplanted over the normal hearts (P < 0.01) and was independent of hemodynamic parameters and immunosuppressive drugs. These results provide unequivocal evidence that the human heart is a site of bFGF production as demonstrated by the presence of bFGF mRNA. The increased ventricular expression of bFGF gene after heart transplantation may be of importance in the mediation of growth and repair of myocardial injury.