title: Combined treatment with erythropoietin and granulocyte colony-stimulating factor enhances neovascularization and improves cardiac function after myocardial infarction.
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.
authors.affiliation: Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China.
authors.forename: Jingyi
authors.initials: J
authors.lastname: Xue
authors.affiliation: Department of Ultrasound, the Second Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150086 China.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Du
authors.affiliation: Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Shi
authors.affiliation: Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Cardiovascular Medicine, Nippon Medical School, Tokyo, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Yasutake
authors.affiliation: Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.affiliation: Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China.
authors.forename: Yihui
authors.initials: Y
authors.lastname: Kong
authors.affiliation: Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China.
authors.forename: Shuxian
authors.initials: S
authors.lastname: Wang
authors.affiliation: Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China.
authors.forename: Fengxiang
authors.initials: F
authors.lastname: Yun
authors.affiliation: Department of Cardiology, the First Clinical Hospital, Harbin Medical University, Harbin, Heilongjiang 150001, China. Email: xuejingyi72@163.com.
authors.forename: Weimin
authors.initials: W
authors.lastname: Li
mesh_terms: D000818:Animals; D015153:Blotting, Western; D054377:Chemokine CXCL12 / Q000378:metabolism; D004452:Echocardiography; D004921:Erythropoietin / Q000627:therapeutic use*; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor / Q000627:therapeutic use*; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000378:metabolism; D018919:Neovascularization, Physiologic / Q000187:drug effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D054377:Chemokine CXCL12; D004921:Erythropoietin; D016179:Granulocyte Colony-Stimulating Factor