These findings suggest that TLR4-signaling activation, triggered by damage-associated molecular patterns, regulates the activation of the NLRP3 inflammasomes and is responsible for the function of the retina in retinal IR injury.

Slit2 overexpression promoted angiogenic effects in both a laser-induced CNV mouse model and HUVECs and promoted the biological activity of endothelial cells. Slit2 may promote angiogenesis by upregulating Robo1 and activating the VEGFR2-ERK1/2 pathway.

Pathological retinal neovascularization and choroidal neovascularization are major causes of vision loss in a variety of clinical conditions, such as retinopathy of prematurity, agerelated macular degeneration, and diabetic retinopathy. Pigment epithelial-derived factor (PEDF) has been found to be the most potent natural, endogenous inhibitor of neovascularization, but its application is restricted because of its instability and short half-life. Polyethylene glycol (PEG) has been used as a drug carrier to slow clearance rate for decades. The present study investigated PEGylated-PEDF for the first time and evaluated its long-term effects on preventing angiogenesis in vitro and in vivo. PEG showed lower cytotoxicity to human umbilical vein endothelial cells (HUVECs). In vitro, PEGylated-PEDF inhibited HUVEC proliferation, migration, tube formation, and vascular endothelium growth factor secretion and induced HUVEC apoptosis in a dose-dependent manner, and it showed a statistically significant difference compared with the PEDF treatment group. In vivo, PEGylated-PEDF had a long-lasting effect in both plasma and retinal concentrations. In an oxygeninduced retinopathy model, one intravitreous injection of PEGylated-PEDF after mouse pups were moved into room air resulted in a significant difference in the inhibition of retinal neovascularization, which decreased the nonperfusion area, compared with the PEDF-treated group. Our present study demonstrated for the first time the long-term inhibitory effects of PEGylated-PEDF on the prevention of neovascularization in vitro and in vivo. These data suggest that PEGylated-PEDF could offer an innovative therapeutic strategy for preventing retinal neovascularization.

No abstract

Endostatin showed convincing inhibitory effects on angiogenesis both in vitro and in vivo. The inhibitory effects may be, at least partly, resulted from the restoration of the PEDF/VEGF ratio. These data suggest that endostatin could offer an innovative pharmaceutical strategy for the prevention of retinal neovascularization.