A critical appraisal of antihyperglycemic and cardioprotective activities of liraglutide: A glucagon-like peptide-1 analog

Diabetes is leading cause for cardiovascular complication, drugs having cardioprotective and antihyperglycemic actions are constantly in search. Oral glucose elicits a three to four times higher peak insulin response compared with an equivalent dose of glucose, if infused intravenously. This is due to the reasons behind, the oral glucose causes a secretion of gut hormones, mainly the glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) which enhance the glucose-induced insulin release. In patients with type 2 diabetes mellitus (type 2 DM), glucose-induced insulin release is unsatisfactory or absent. Because of this type 2 DM patients are unable to adjust their insulin secretion as per the need exist. GLP-1 secretion (but not GIP secretion) is diminished in patients with type 2 diabetes. However, when the GLP-1 and GIP agonist are administered in patients with type 2 diabetes, they elicit insulin secretion resulting in lowering of blood glucose level. In addition to its insulin stimulatory effect, GLP-1 agonist also induces cardioprotective effects. It increases nuclear respiratory factor-2 (Nrf2) and heamoxigenase-1(Ho-1) in cell which have antioxidant and cardioprotective property. GLP-1 maintains islets integrity and reduces apoptotic cell death of human islet cells in culture. Improved understanding of the mechanism of action and clinical effects of incretin-based therapies would be useful in advancement of its appropriate use in clinical practices.