Reduction of experimental diabetic vascular leakage by deliveryof angiostatin with a recombinant adeno-associated virus vector

[摘要] Purpose: To evaluate the efficacy of recombinant adeno-associatedvirus (rAAV) vector expressing mouse angiostatin (Kringle domains 1 to4) in reducing retinal vascular leakage in an experimental diabetic ratmodel.Methods: rAAV-angiostatin was delivered by intravitreal injection tothe right eyes of Sprague-Dawley rats. As a control, the contralateraleye received an intravitreal injection of rAAV-lacZ. Gene delivery wasconfirmed by reverse-transcriptase polymerase chain reaction (RT-PCR).Diabetes was induced by intravenous injection of streptozotocin (STZ).Vascular permeability changes were evaluated by extravascular albuminaccumulation and leakage of intravenous-injected fluoresceinisothiocynate-bovine serum albumin (FITC-BSA). Effects ofrAAV-angiostatin on expression of vascular endothelial growth factor(VEGF), pigment epithelium-derived factor (PEDF), occludin, andphospho-p42/p44 MAP kinase in retina tissue were analyzed by westernblotting.Results: The rAAV-angiostatin injections led to sustainedangiostatin gene expression in retina as confirmed by RT-PCR, andreduced extravascular albumin accumulation in STZ-induced diabeticretina. Further, rAAV-angiostatin significantly decreasedintravascularly injected FITC-BSA leakage at 5 days (p=0.001), 10 days(p<0.001), and 15 days (p=0.001) after STZ-induced diabetes, ascompared to the control eyes receiving rAAV-lacZ. Expression of VEGF andphosphorylation of p42/p44 MAP kinase in retina was reduced byrAAV-angiostatin at day 1 (p=0.043 for both VEGF and phospho-p42/p44 MAPkinase) after STZ-induced diabetes compared with rAAV-lacZ eyes.rAAV-angiostatin reduced retinal occludin loss at 10 days afterSTZ-induced diabetes (n=5, p=0.041). There was no significant differencein retinal PEDF expression between eyes injected with rAAV-angiostatinand rAAV-lacZ.Conclusions: Intravitreal delivery of rAAV-angiostatin reducesvascular leakage in an STZ-induced diabetic model. This effect isassociated with a reduction in the retinal occludin loss induced bydiabetes and downregulation of retinal VEGF and phosphor-p42/p44 MAPkinase expression. This gene transfer approach may reduce diabeticmacular edema, providing protection in diabetic patients at risk formacular edema.

[学科分类] 生物化学/生物物理