SIRT1 and ischemia: In particular, SIRT1-deficient endothelial cells were found to display significantly reduced sprouting and branching capabilities, which was followed by impaired ischemia-induced neovascularization [53], whereas SIRT1 activation by resveratrol resulted in an upregulation of proangiogenic vascular endothelial growth factor in the rat myocardial infarction model [54].