INS and type 2 diabetes mellitus: Since the comparative effects of pioglitazone versus metformin (both insulin sensitizers) in regards to the possible improvement of the cardiovascular prognosis in patients with T2DM are still elusive, the aim of the proposed study by Naka et al. (2012) [18] was to assess and compare the effects of pioglitazone and metformin on vascular endothelial function in patients with uncontrolled T2DM treated only with glimepiride, a sulfonylurea drug.