To determine whether diabetes contributes to the cochlear microvasculature, platelet endothelial cell adhesion molecule (PECAM)-1 (CD 31), expressed at high levels on the surface of endothelial cells, was assessed using an immunofluorescence assay (Figure 4A,B), and cochlear blood flow (Figure 4D) was measured via laser Doppler flowmetry. This evidence concerns the gene PECAM1 and diabetes mellitus.