Pericytes and the Pathogenesis of Diabetic Retinopathy

Pericytes provide vascular stability and control endo-thelial proliferation. Pericyte loss, microaneurysms, and acellular capillaries are characteristic for the dia-betic retina. Platelet-derived growth factor (PDGF)-B is involved in pericyte recruitment, and brain capillaries of mice with a genetic ablation of PDGF-B show pericyte loss and microaneurysms. We investigated the role of capillary coverage with pericytes in early diabetic reti-nopathy and the contribution to proliferative retinopa-thy using mice with a single functional allele of PDGF-B (PDGF-B/ mice). As assessed by quantitative mor-phometry of retinal digest preparations, pericyte num-bers in nondiabetic PDGF-B/ mice were reduced by 30 % compared with wild-type mice, together with a small but significant increase in acellular capillaries