Neovascularization in ischaemic heart by newly isolated tannins prevents cardiomyocyte apoptosis and improves cardiac function

Ischaemic heart disease remains the leading cause of morbidity and mortality in most countries. Severe ischaemia of myocardium induces myocardial infarction and results in an irreversible loss of myocardium. Restoration of coronary blood flow by rapid angiogenesis may offer a direct and effective therapeutic way to intractable ischaemic heart diseases.;In the present study, an angiogenic tannins fraction (AngioT) was isolated from Geum. japonicum Thunb. Var. Chinense F. Bolle using bio-assay guided strategy. AngioT increased the proliferation of human umbilical vein endothelial cell (HUVEC) in culture within 24-hour, 48-hour and 72-hour treatment in a dose-dependent pattern. The EC50 of AngioT on HUVEC was less than 25mug/ml. Conditional media from AngioT treated HUVEC stimulated the proliferation of HUVEC significantly greater than conditional media from non-treated HUVEC. Using 2-dimensional electrophoresis and MALDI-TOF, VEGFa was identified in the AngioT treated conditional medium.;Acute myocardial infarction (AMI) rat model was adopted to test the effect of AngioT in vivo. AngioT was directly injected into the ischaemic region of the left ventricle immediately after the ligation of left anterior descending artery. The densities of vessels in AngioT treated hearts were on average 3-4 folds higher compared with non-treated hearts after two and seven days post infarction. Using TUNEL method, approximately 3-fold lower numbers of apoptotic cardiomyocytes were detected in AngioT treated AMI hearts compared with controls. The infarcted volume estimated by Masson's Trichrome staining was significantly decreased in AngioT treated hearts (27.44%+/-7.34% vs. 39.53%+/-5.97%, p<0.05) compared with control hearts 14 days post infarction. Echocardiography demonstrated that left ventricular ejection fraction and fraction shortening in AngioT treated hearts were significantly improved by 10.4% and 22.3% compared to those in the control hearts 2-day post infarction (p<0.05). These improvements were maintained for 2-week post infarction.;Based on the analysis of rat angiogenesis specific superarray, VEGFb, VEGFc and FGF7, were found to be highly expressed in AngioT treated AMI hearts compared to the controls. The expression levels of survival related genes Bcl2 and Akt1 were increased to 3.3 and 2.8 folds respectively in AngioT treated AMI hearts compared with the controls (both p<0.05). Based on the signal transduction pathway finder superarray, Jak-Stat pathway activators, Interleukin 4 receptor and Interferon regulatory factor 1 (IL4R and IRF1), were found to be highly expressed in the AngioT treated AMI heart.;In conclusion, bioactive angiogenic factors (AngioT) were isolated from Geum. japonicum Thunb. Var. Chinense F. Bolle (GJ). Intra-cardiomuscular injection of AngioT had beneficial effects on the acute myocardial infarction. The underlying mechanisms might be related to the activation of Jak-Stat Pathway and over expressions of angiogenic factors and survival associated genes. The therapeutic properties of AngioT appear entirely novel and may provide a new dimension for therapeutic angiogenesis for the treatment of acute ischaemic heart disease.;Key words. ischaemic heart disease; myocardial infarction; therapeutic angiogenesis; Geum japonicum; apoptosis; tannins; VEGF; Jak-Stat pathway...