Disclosed herein are compositions of GHRH agonists and peptides, and methods to treat disorders, such as ischemia and reperfusion injury. In one embodiment, a method of treating a reperfusion injury in a subject in need may involve administering a therapeutically effective amount of at least one GHRH agonist peptide to the subject. In additional embodiment, a method of promoting vasculogenesis in a mammal may involve administering a therapeutically effective amount of at least one GHRH agonist peptide to the subject. In a further embodiment, a method of promoting differentiation of mesenchymal stem cells into endothelial cells may involve contacting mesenchymal stem cells with at least one GHRH agonist peptide.