Pulsatile stretch stimulates vascular endothelial growth factor (VEGF) secretion by cultured rat cardiac myocytes

Evidence has accumulated that vascular endothelial growth factor (VEGF) is expressed in the heart, and its expression is markedly increased in respons e to hypoxia, Recently, it was shown that pulsatile myocardial stretch in v ivo markedly enhanced VEGF mRNA level in the heart. To investigate whether pulsatile mechanical stretch really stimulates VEGF expression by cardiac m yocytes, using an in vitro preparation, we examined the secretion of VEGF i nto the culture media from cardiac myocytes subjected to pulsatile stretch. We found that pulsatile mechanical stretch induced rapid secretion of VEGF by cultured rat cardiac myocytes and mRNA expression of VEGF and VEGF rece ptors in the cardiac myocytes, We also found that the stretch-induced secre tion of VEGF was at least in part mediated by TGF-beta. These data provide the direct evidence that mechanical overload itself can induce VEGF secreti on by cardiac myocytes, which may play a role in ameliorating the relative myocardial hypoxia, (C) 1999 Academic Press.