Endothelin-1, a regulator of angiogenesis in the chick chorioallantoic membrane

J Vasc Res. Nov-Dec 2001;38(6):536-45. doi: 10.1159/000051089.

Abstract

We investigated the angiogenic properties of endothelin-1 (ET-1) using a novel experimental approach involving the constant production and release of ET-1, which was achieved by grafting stably transfected Chinese hamster ovary (CHO) (CHO-ET-1) cell aggregates onto the chorioallantoic membrane (CAM) ectoderm. Macroscopic observation showed that CHO-ET-1 cell aggregates formed highly vascularized nodules surrounded by radially rearranged vessels, with a strong angiogenic response. 5-Bromo-2'-deoxy-uridine (BrdU) studies showed an increase in endothelial cell proliferation in the CAM vasculature around CHO-ET-1 nodules. An angiogenic response was also observed with gelatin sponges containing conditioned medium from CHO-ET-1 cells. The specific involvement of ET-1 in the angiogenic effect mediated by CHO-ET-1 was demonstrated by the reduction or abolition of neovascularized CHO-ET-1 nodules by (1) bosentan, a mixed antagonist of ET(A)/ET(B) receptors, (2) an ET(A) receptor antagonist (Ru69986) and (3) phosporamidon, an inhibitor of endothelin-converting enzyme-1 (ECE-1). We also demonstrated that VEGF was involved in CHO-ET-1-mediated angiogenesis, by using a specific inhibitor of VEGF tyrosine kinase receptor activity (PTK787/ZK 222584), which abolished CHO-ET-1 nodule formation and CAM neovascularization. Thus, our results show that exogenous ET-1 mediates angiogenesis in vivo.

MeSH terms

  • Allantois / blood supply*
  • Animals
  • CHO Cells
  • Chick Embryo
  • Chorion / blood supply*
  • Cricetinae
  • Culture Media / pharmacology
  • Culture Techniques
  • Endothelin-1 / pharmacology*
  • Endothelium, Vascular / embryology
  • Neovascularization, Physiologic / drug effects*

Substances

  • Culture Media
  • Endothelin-1