Important role of erythropoietin receptor to promote VEGF expression and angiogenesis in peripheral ischemia in mice

Circ Res. 2007 Mar 16;100(5):662-9. doi: 10.1161/01.RES.0000260179.43672.fe. Epub 2007 Feb 9.

Abstract

We have recently demonstrated that endogenous erythropoietin (Epo)/Epo receptor (EpoR) system plays an important protective role in hypoxia-induced pulmonary hypertension. However, it remains to be examined whether vascular EpoR system contributes to angiogenesis in response to ischemia. We examined angiogenesis in EpoR(-/-)-rescued mice that lack EpoR in most organs including cardiovascular system except erythroid-lineage cells. Two weeks after femoral artery ligation, blood flow recovery, activation of VEGF/VEGF receptor system, and mobilization of endothelial progenitor cells were all impaired in EpoR(-/-)-rescued mice as compared with wild-type (WT) mice. Bone marrow (BM) transplantation with WT-BM cells in EpoR(-/-)-rescued mice partially but significantly improved blood flow recovery after hindlimb ischemia. The extent of VEGF upregulation and the number of BM-derived cells in ischemic tissue were significantly less in EpoR(-/-)-rescued mice compared with WT mice even after BM reconstitution with WT-BM cells. Similarly, the recovery of blood flow was significantly impaired in recipient EpoR(-/-)-rescued mice that had been transplanted with WT-BM or EpoR(-/-)-rescued-BM as compared with recipient WT mice. Furthermore, the Matrigel implantation assay and aortic ring assay showed that microvessel growth in vitro was significantly reduced in EpoR(-/-)-rescued mice as compared with WT mice. These results indicate that vascular EpoR system also plays an important role in angiogenesis in response to hindlimb ischemia through upregulation of VEGF/VEGF receptor system, both directly by enhancing neovascularization and indirectly by recruiting endothelial progenitor cells and BM-derived proangiogenic cells.

Publication types

  • Comparative Study

MeSH terms

  • Animals
  • Cell Movement / genetics
  • Endothelium, Vascular / metabolism
  • Endothelium, Vascular / pathology
  • Hindlimb / blood supply*
  • Hindlimb / metabolism
  • Humans
  • Ischemia / genetics
  • Ischemia / metabolism*
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mice, Transgenic
  • Neovascularization, Pathologic / genetics
  • Neovascularization, Pathologic / metabolism*
  • Neovascularization, Pathologic / physiopathology*
  • Receptors, Erythropoietin / physiology*
  • Stem Cells / metabolism
  • Stem Cells / pathology
  • Up-Regulation / genetics
  • Vascular Endothelial Growth Factor A / biosynthesis*
  • Vascular Endothelial Growth Factor A / genetics

Substances

  • Receptors, Erythropoietin
  • Vascular Endothelial Growth Factor A