A year ago we isolated from diseased and normal human left ventricular myocardium, factors of molecular weight 14,000 to 18,000, which were mitoganic for fibroblast and which could be identified on western blotting with some antisera to acidic and basic fibroblast growth factors. This year we found that thess growth activities are destroyed by heat, acid, or tripsin, blocked by anti-FGF antisera and by protamine (which blocks the FGF receptors). They also stimulated capillary endothelial cell migration and displaced bFGF in a radioreceptor assay. We confirmed the immunological similarities to aFGF and bFGF with several more antisera and also proved the specificity of these by showing that these bands were no longer produced on Western blotting after the antiserum had absorbed to excess recombinant aFGF or bFGF respectively. Some immuno-reactivity was also seen at Mr 35,000, which may represent the FGF precursor. These growth factors were also present in right atrial tissue (but not in blood) and were present in a sample of fresh nonischemic normal heart as well, indicating that they are not due to rapid synthesis in response to agonal ischemia. FGF peptides may normally have morphogenic and neurotropic functions but we are currently investigating their potential roles in pathologic processes such as ischemia and hypertrophy.
