Dipeptidyl peptidase-4 (DPP-4) inhibitors are novel drugs for the treatment of type 2 diabetes mellitus. They exert their action through inhibition of the catabolism of locally secreted incretins such as glucagon-like peptide-4 (GLP-4) and glucose-dependent insulinotropic polypeptide (GIP) by inhibiting enzyme DPP-4. GLP-1 and GIP are secreted from the gastrointestinal tract in response to food intake. GLP-1 is secreted from L cells present in the mucosa of the small intestine and colon, whereas GIP is secreted from K cells of the jejunum. These 2 incretins lower blood glucose levels and postprandial hyperglycemia by stimulating insulin release from b cells of the pancreas, thus increasing insulin sensitivity, delaying gastrointestinal emptying, decreasing food intake through early satiety, and causing weight loss in the long term. However, their action is short-lived (2 to 3 minutes) because of catabolism by the DPP-4 enzyme. The importance of DPP-4 inhibitors lies in their blockade of the DPP-4 enzyme leading to the prevention of their catabolism and thus increasing their blood levels, extending the duration of their action, and improving their blood glucose-lowering effect. In addition to their antidiabetic action, recent experimental and clinical studies have demonstrated a pleiotropic cardiovascular protective effect of these agents independent of their antidiabetic action. They prevent atherosclerosis, improve endothelial dysfunction, lower blood pressure, and prevent myocardial injury. All these actions are discussed in this concise review. In conclusion, DPP-4 inhibitors are novel antidiabetic agents with pleiotropic cardiovascular protective effects in addition to their antidiabetic action.
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