ICAM1 and diabetes mellitus: Usingin situ perfusion methods, evidence consistent with capillary occlusionsecondary to leukostasis has been observed in occasional retinal vessels(Figure 2), but it is unclear whether this occurred in vivo or was an artifactcaused by the in vitro perfusion.Retinas from diabetic mice lacking ICAM-1 and CD18 are protected from the development of diabetes-induced increase in leukostasis, vascular permeability,and degeneration of retinal capillaries [46],showing these proteins to be important in the development of early stages of diabetic retinopathy.