GCG and type 2 diabetes mellitus: Moreover, it is recently reported that sitagliptin, a dipeptidyl peptidase-4 (DPP-4) inhibitor-enhanced glucagon-like peptide-1 may ameliorate LV diastolic dysfunction in T2DM by shifting fatty acid to glucose utilization in the cardiomyocyte, and thus, improving cardiac efficiency and reducing lipolysis [31–33].