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Purpose: That vascular endothelial growth factor (VEGF) plays a major role in inflammatory angiogenesis has been well established. This pilot study was designed to evaluate experimental treatment with bevacizumab eyedrops in corneal neovas-cularization induced by alkali burn. The feasibility of topical administration, cor-neal cell viability and corneal penetration were investigated in an animal model. Methods: Eighteen chinchilla bastard rabbit corneas injured with 1 m NaOH were divided into three groups: untreated, early and late treatment groups. Eyedrops of bevacizumab solution (25 mg ⁄ ml) were administered five times daily. Clinical examination under stereoscopic microscope was performed to evaluate corneal opacity, neovascularization, vessel size and oedema. Histopathology was analysed for vessel density and apoptotic reaction. Additionally, intracameral bevacizumab concentration was measured with enzyme-linked immunosorbent assay (ELISA) after repeated topical applications. Results: A fast increase in aqueous bevacizumab concentration was achieved when the solution was instilled every minute onto a healthy eye surface. As well as clear anti-angiogenic effects, anti-fibrotic effects were also seen after corneal burn, maintaining corneal transparency. Early treatment of actively growing vessels showed a significantly better outcome, although apoptosis of pre-existing vessels could also be induced by the late treatment. No specific toxicity was seen regarding epithelium, keratocytes or endothelium. Conclusions: The data from this pilot study suggest that bevacizumab eyedrops can sufficiently penetrate the corneal stroma and anterior chamber. When administered soon after alkali burn, bevacizumab seems to significantly reduce corneal damage. Combinations of established treatment regimens with topical bevacizumab might be considered in severe injuries with otherwise devastating prognoses.

Aim: To evaluate the antiproliferative and cytotoxic properties of bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), on human retinal pigment epithelium (ARPE19) cells, rat retinal ganglion cells (RGC5), and pig choroidal endothelial cells (CEC). Methods: Monolayer cultures of ARPE19, RGC5, and CEC were used. Bevacizumab (0.008-2.5 mg/ml), diluted in culture medium, was added to cells that were growing on cell culture dishes. Cellular proliferative activity was monitored by 59-bromo-29-deoxyuridine (BrdU) incorporation into cellular DNA and the morphology assessed microscopically. For cytotoxicity assays ARPE19, RGC5, and CEC cells were grown to confluence and then cultured in a serum depleted medium to ensure a static milieu. The MTT test was performed after 1 day. The ''Live/Dead'' viability/cytotoxicity assay was performed and analysed by fluorescence microscopy after 6,12,18,24, 30, 36, and 48 hours of incubation. Expression of VEGF, VEGF receptors (VEGFR1 and VEGFR2) and von Willebrand factor was analysed by immunohistochemistry. Results: No cytotoxicity of bevacizumab on RGC5, CEC, and ARPE19 cells could be observed after 1 day. However, after 2 days at a bevacizumab concentration of 2.5 mg/ml a moderate decrease in ARPE19 cell numbers and cell viability was observed. Bevacizumab caused a dose dependent suppression of DNA synthesis in CEC as a result of a moderate antiproliferative activity (maximum reduction 36.8%). No relevant antiproliferative effect of bevacizumab on RGC5 and ARPE19 cells could be observed when used at a concentration of 0.8 mg/ml or lower. CEC and ARPE 19 cells stained positively for VEGF, VEGFR1, and VEGFR2. More than 95% of the CEC were positive for von Willebrand factor. Conclusions: These experimental findings support the safety of intravitreal bevacizumab when used at the currently applied concentration of about 0.25 mg/ml. Bevacizumab exerts a moderate growth inhibition on CEC when used in concentrations of at least 0.025 mg/ml. However, at higher doses (2.5 mg/ml) bevacizumab may be harmful to the retinal pigment epithelium.

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Capillaries derived from the perineural vascular plexus invade brain tissue early in embryonic development. Considerably later they differentiate into blood‐brain barrier (BBB)‐forming blood vessels. In the chick, the BBB as defined by impermeability for the protein horseradish peroxidase develops around embryonic day 13. We have previously found that brain endothelial cells start to express a number of proteins at around the same time, suggesting that these proteins play a role in BBB function. Here we describe a 74 kd protein defined by the monoclonal antibody HT7 that is expressed on the surface of chick embryonic blood cells and brain endothelial but on no other endothelial cells. This protein is not detectable on early embryonic brain endothelium, but is expressed by these cells on embryonic day 10. It is absent in choroid plexus endothelial cells which represent permeable fenestrated endothelial cells. The antigen is expressed on choroid plexus epithelium which is the site of the blood‐cerebrospinal fluid barrier. Since it is also found in basolateral membranes of kidney tubules, it may be involved in specific carrier mechanisms. Embryonic mouse brain tissue transplanted on the chick chorio‐allantoic membrane induces the expression of this antigen on endothelial cells derived from the chorio‐allantois. Brain tissue can therefore induce in endothelial cells in vivo the expression of a molecule characteristic of brain endothelium.

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Biopolymers based on UV cross-linked hyaluronic acid may be promising vitreous substitutes.

These results demonstrate the neuroprotective effect of H-1152P-mediated ROCK-inhibition on retinal cells under stress, which may rely partly on the attenuation of glial cell reactivity.