Jingyi Xue1, Guoqing Du2, Jing Shi1, Yue Li1, Masahiro Yasutake3, Lei Liu1, Jianqiang Li1, Yihui Kong1, Shuxian Wang1, Fengxiang Yun1, Weimin Li4. 1. Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China. 2. Department of Ultrasound, the Second Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150086 China. 3. Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan. 4. Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China. Email: xuejingyi72@163.com.
Abstract
BACKGROUND: Erythropoietin (EPO) and granulocyte colony-stimulating factor (G-CSF) are both potential novel therapeutics for use after myocardial infarction (MI). However, their underlying mechanisms remain unclear and the efficacy of monotherapy with EPO or G-CSF is also controversial. Therefore, we investigated the effects of combined treatment with EPO and G-CSF on neovascularization and cardiac function in post-infarction rats and explored the potential mechanisms. METHODS: Four groups of rats were used: control (saline injection after MI, i.h.), EPO (a single dose of 5 000 IU/kg after MI, i.h.), G-CSF (a dose of 50 µg× kg(-1)× d(-1) for 5 days after MI, i.h.), and both EPO and G-CSF (EPO+G-CSF, using the same regiment as above). Cardiac function was assessed by echocardiography before and 1 day, 7 days, 14 days and 21 days after MI. CD34(+)/Flk-1(+) cells in the peripheral blood were evaluated by flow cytometry before and 3 days, 5 days and 7 days after MI. The infarct area and angiogenesis in the peri-infarct area were analyzed. The mRNA and protein expression of vascular endothelial growth factor (VEGF) and stromal-derived factor-1a (SDF-1α) in the peri-infarct area were detected by real-time quantitative RT-PCR and Western blotting. RESULTS: Compared with the control and monotherapy groups, the EPO+G-CSF group had significantly increased CD34(+)/Flk-1(+) endothelial progenitor cells (EPCs) in the peripheral blood (P < 0.05), up-regulated VEGF and SDF-1α levels in the peri-infarct region (P < 0.05), enhanced capillary density (P < 0.05), reduced infarct size (P < 0.05) and improved cardiac structure and function (P < 0.05). G-CSF alone did not dramatically increase EPCs in the peripheral blood, enhance capillary density in the peri-infarct area or reduce infarct size compared with the control group. CONCLUSIONS: Combined treatment with EPO and G-CSF increased EPCs mobilization, up-regulated VEGF and SDF-1α levels in the post-infarction microenvironment, subsequently enhanced neovascularization in the peri-infarct region and reduced infarct size. All factors contributed to its beneficial effects on cardiac function in post-infarction rats.
BACKGROUND:Erythropoietin (EPO) and granulocyte colony-stimulating factor (G-CSF) are both potential novel therapeutics for use after myocardial infarction (MI). However, their underlying mechanisms remain unclear and the efficacy of monotherapy with EPO or G-CSF is also controversial. Therefore, we investigated the effects of combined treatment with EPO and G-CSF on neovascularization and cardiac function in post-infarctionrats and explored the potential mechanisms. METHODS: Four groups of rats were used: control (saline injection after MI, i.h.), EPO (a single dose of 5 000 IU/kg after MI, i.h.), G-CSF (a dose of 50 µg× kg(-1)× d(-1) for 5 days after MI, i.h.), and both EPO and G-CSF (EPO+G-CSF, using the same regiment as above). Cardiac function was assessed by echocardiography before and 1 day, 7 days, 14 days and 21 days after MI. CD34(+)/Flk-1(+) cells in the peripheral blood were evaluated by flow cytometry before and 3 days, 5 days and 7 days after MI. The infarct area and angiogenesis in the peri-infarct area were analyzed. The mRNA and protein expression of vascular endothelial growth factor (VEGF) and stromal-derived factor-1a (SDF-1α) in the peri-infarct area were detected by real-time quantitative RT-PCR and Western blotting. RESULTS: Compared with the control and monotherapy groups, the EPO+G-CSF group had significantly increased CD34(+)/Flk-1(+) endothelial progenitor cells (EPCs) in the peripheral blood (P < 0.05), up-regulated VEGF and SDF-1α levels in the peri-infarct region (P < 0.05), enhanced capillary density (P < 0.05), reduced infarct size (P < 0.05) and improved cardiac structure and function (P < 0.05). G-CSF alone did not dramatically increase EPCs in the peripheral blood, enhance capillary density in the peri-infarct area or reduce infarct size compared with the control group. CONCLUSIONS: Combined treatment with EPO and G-CSF increased EPCs mobilization, up-regulated VEGF and SDF-1α levels in the post-infarction microenvironment, subsequently enhanced neovascularization in the peri-infarct region and reduced infarct size. All factors contributed to its beneficial effects on cardiac function in post-infarctionrats.