Effect of intravenous heparin on serum levels of endostatin, VEGF and HGF: author's reply

We thank Dr Bhatia, Dr Clesham and Dr Turner for their interest in our paper [1], and we agree with them that the studies on the serum levels of endostatin, VEGF and HGF under administration of heparin should be interpreted very carefully, and there is an important limitation in our study. However, we disagree with them on some points as follows. We think that the significant decrease in serum VEGF levels after reperfusion may be due to down-regulation of VEGF production (although we did not state in our paper) as well as internalization of VEGF after binding to its receptor (which may be facilitated by heparin [2]). VEGF was shown to be internalized in HUVECs (human umbilical vein endothelial cells) [3]. In fact, we found that VEGF concentrations in culture supernatants of cardiac myocytes increased rapidly and then decreased in response to acute hypoxia...