Long-term dietary intake of pasta enriched with barley (1–3) beta-d-glucan induces neovascularization-mediated cardioprotection against ischemia/reperfusion injury in mice

Background: The modulation of angiogenesis is known to be a strategy to increase heart resistance to ischemia/reperfusion (I/R). Whereas the angiogenic activity of barley (1- 3)beta-D-Glucan (BG) have been characterized in vitro, there are no clear experimental data demonstrating that chronic dietary intake and intestinal absorption of BG actually protects the heart against I/R. We tested whether long-term consumption of 3% w/v BG included in normal pasta would increase myocardial angiogenesis and render the heart of mice more resistant to I/R. Materials and methods: Healthy adult male C57BL/6 mice were fed for 5 weeks with a low-fat diet supplemented with pasta enriched with BG (3g/100mg) (BG, n=15) or regular pasta (control, n=15). Food intake, glucose tolerance test and cardiac function were weekly assessed. At fifth week of diet, anesthetized mice underwent to 30 min of cardiac ischemia followed by 60 min of reperfusion. The myocardial infarction was induced by ligation of the left anterior descending artery. The myocardial capillary density and infarct size/area at risk were assessed ex vivo. Myocardial Vascular Endothelial Growth Factor 165 (VEGF165) expression and anion superoxide (O2-) levels were measured respectively by western blot and dihydroethidium staining. To evaluate the paracrine activation of protective angiogenesis by BG, we measured the expression of VEGF165, a well known pro-angiogenic growth factor, in endothelial cells exposed for 7 days to 3% BG. Finally, we examined the expression of dectin-1, a receptor of BG, in both endothelial cells and cardiomyocytes. Results: At similar food intake, 3% w/v BG did not affect body weight, glucose metabolism and cardiac function of mice. At the end of reperfusion, BG mice survived 50±2% more than control (P<0.01). Infarct size/area at risk and myocardial O2- load were reduced respectively by 62±5% (P<0.001) and 35±4% (P<0.0001) in β-D-glucan mice. Myocardial capillary density and VEGF165 expression were increased respectively by 12±0.6% (P<0.05) and 47.6±1% (P<0.001) in BG group compared to control mice. In vitro, VEGF165 expression was significantly increased in BG-treated endothelial cells (P<0.001). Dectin-1 was expressed in endothelial cells, but not in cardiomyocytes. Conclusions: Long-term intake of BG-rich diet augments myocardial capillary density and reduces infarct size by sustained expression of VEGF165 in endothelial cells, which express dectin-1. Our findings suggest important potential health benefits of pasta-rich in BG and emphasize the need to develop BG-rich functional foods with protective activities for increasing heart resistance to I/R injury.