PECAM1 and type 1 diabetes mellitus: CD31 staining revealed an increased total endothelial length per total islet area (vascular density) in subjects with T1D compared with non-diabetic subjects (median total endothelial length per total islet area was 0.015 μm/μm2 and 0.0085 respectively) (p = 0.0263) (Fig 4).