Both ionic forms of europium and terbium show proangiogenesis effect in vitro and in vivo. A. Primary cell culture with 1 µg/ml Eu or Tb. i) Blank control, ii) 20 ng/ml VEGF, iii) 1 µg/ml Eu, iv) 1 µg/ml Tb. B. Compared with blank control, an increase of GFP+ cells can be observed after Eu or Tb treatment. C. Zebrafish embryos at 72 hpf. i) Blank control, ii) 100 µg/ml Eu Rods, iii) 100 µg/ml Eu, iv) 100 µg/ml Tb. The recovering ISV shows the proangiogenesis ability of ionic forms of europium and terbium. D. Graph to show number of ISV recovered embryos. E. Graph to show average ISV sprouts per embryo.