Negative Inotropic Effect of Basic Fibroblast Growth Factor on Adult Rat Cardiac Myocyte

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Abstract
Background Basic fibroblast growth factor (bFGF) is highly expressed in the myocardium in some cardiac disorders, such as ischemia-reperfusion and cardiac allograft rejection. However, whether bFGF has any effects on myocardial contraction is unknown. Methods and Results We examined the effects of bFGF on myocardial contractility using isolated adult rat cardiac myocyte preparations. bFGF exerted a direct negative inotropic effect that was concentration and time dependent. The pretreatment of myocytes with a neutralizing anti-bFGF antibody (100 ng/mL) abolished the negative inotropic effects of bFGF (100 ng/mL). Platelet-derived growth factor (12.5 ng/mL) and transforming growth factor-β (1 ng/mL) did not exert such effects, which indicated that bFGF-induced negative inotropism was considered to be specific for this growth factor. bFGF decreased the peak intracellular Ca 2+ transient by 46% during systole. The enhanced production of nitric oxide was unlikely to be responsible for the bFGF-induced negative inotropic effect. Conclusions bFGF, primarily a potent growth promoter, produced acute negative inotropic effects in the adult cardiac myocyte that could have resulted from alterations in intracellular Ca 2+ homeostasis. The negative inotropic effect of bFGF may contribute to myocardial dysfunction associated with ischemia-reperfusion injury and heart transplant rejection.