EPCs were pre-treated with L-NAME (1 mM) for 30 min, and then treated with AICAR (1 mM). (A) After 1.5 hr, cells were lysed and cell lysates underwent western blotting to detect phosphorylation of AMPK and levels of VE-Cadherin (VE-Cad), vWF and ICAM-1. (B) Cells were treated without or with L-NAME (1 mM) for 30 min, then without or with AICAR (1 mM) for 6 hr, then tube formation in Matrigel was assessed. Results are mean ± SD from 3 independent experiments, each performed in triplicate (*p<0.05).