TROPHIC EFFECT OF HUMAN PERICARDIAL FLUID ON ADULT CARDIAC MYOCYTES -DIFFERENTIAL ROLE OF FIBROBLAST GROWTH-FACTOR-II AND FACTORS RELATED TO VENTRICULAR HYPERTROPHY

PericardiaI fluid (PF) may contain myocardial growth factors that exer t paracrine actions on cardiac myocytes. The aims of this study were ( 1) to investigate the effects of human PF and serum, collected from pa tients undergoing cardiac surgery, on the growth of cultured adult rat cardiac myocytes and (2) to relate the growth activity of both fluids to the adaptive changes in overloaded human hearts. Both PF and serum increased the rate of protein synthesis, measured by [C-14]phenylalan ine incorporation in adult rat cardiomyocytes (PF, +71.9+/-8.2% [n=17] ; serum, +14.9+/-6.5% [n=13]; both P<.01 versus control medium). The e ffects of both PF and serum on cardiomyocyte growth correlated positiv ely with the respective left ventricular (LV) mass. However, the magni tude of change with PF was 3-fold greater than with serum (P<.01). The se trophic effects of PF were mimicked by exogenous basic fibroblast g rowth factor (FGF2) and inhibited by anti-FGF2 antibodies and transfor ming growth factor-beta (TGF-beta), suggesting a relationship to FGF2. In addition, FGF2 concentration in PF was 20 times greater than in se rum. On the other hand, the LV mass-dependent trophic effect, present in both fluids, was independent of FGF2 concentration or other factors , such as angiotensin II, atrial natriuretic factor, and TGF-beta. The se data suggest that FGF2 in human PF is a major determining factor in normal myocyte growth, whereas unidentified LV mass-dependent factor( s), present in both PF and serum, participates in the development of v entricular hypertrophy.