Blockade of Annexin A2 Prevents Early Microvasculopathy in Murine Models of Diabetic Retinopathy

We examined the role of annexin A2 (A2) in the development of diabetic retinal vasculopathy by testing the effect of Anxa2 gene deletion as well as administration of anti-A2 antibodies on pericyte dropout and retinal neovascularization in diabetic Akita mice, and in mice subjected to oxygen-induced retinopathy. We analyzed diabetic Ins2AKITA mice with or without global deletion of Anxa2, as well as Ins2AKITA mice that received intravitreal anti-A2 IgG or control antibody at 2, 4, and 6 months, for retinal pericyte dropout at 7 months of age. In addition, we assessed the effect of intravitreal anti-A2 on oxygen-induced retinopathy (OIR) in neonatal mice by quantifying retinal neovascular and vaso-obliterative area, and by enumeration of neovascular tufts. Both deletion of the Anxa2 gene and immunologic blockade of A2 prevented pericyte depletion in retinas of diabetic Ins2AKITA mice. Blockade of A2 also reduced vaso-obliteration and neovascularization in the OIR model of vascular proliferation. This effect was amplified when a combination of antivascular endothelial growth factor (VEGF) and anti-A2 antibodies was used. Therapeutic approaches that target A2, alone or in combination with anti-VEGF therapy, are effective in mice, and may also curtail the progression of retinal vascular disease in humans with diabetes.