CD34 and diabetes mellitus: Immunohistochemical scores of CD34 and VEGF immunoreactivities in non-treated diabetes group (TD), Pioglitazone group (P), Linagliptin group (L), and Pioglitazone and Linagliptin group (PL). Data of H-SCORE were given as mean ± standard deviation. CD (Cluster of differentiation) VEGF (Vascular endothelial growth factor)