Blood vessels function as conduits for the delivery of O(2) and nutrients. Hypoxia-inducible factor 1 (HIF-1) mediates adaptive transcriptional responses to hypoxia/ischemia that include expression of angiogenic cytokines/growth factors by hypoxic cells and expression of cognate receptors for these ligands by vascular cells and their progenitors. Impairment of HIF-1-dependent responses to hypoxia is a major factor contributing to the impaired vascular responses to ischemia that are associated with aging and diabetes.
