Three-Year Follow-Up of Phase 1 and 2a rAAV.sFLT-1 Subretinal Gene Therapy Trials for Exudative Age-Related Macular Degeneration.

Purpose: To assess the safety and the 3-year results of combined phase 1 and 2a randomized controlled trials of rAAV.sFLT-1 gene therapy (GT) for wet age-related macular degeneration.

Design: Phase 1/2a clinical trial.

Gene Therapy in Neovascular Age-related Macular Degeneration: Three-Year Follow-up of a Phase 1 Randomized Dose Escalation Trial.

Purpose: To assess the safety of rAAV.sFlt-1 subretinal injection in neovascular age-related macular degeneration (wet AMD) over 36 months.

Design: Phase 1 dose escalation trial.

Phase 2a Randomized Clinical Trial: Safety and Post Hoc Analysis of Subretinal rAAV.sFLT-1 for Wet Age-related Macular Degeneration.

Background: We present the results of a Phase 2a randomized controlled trial investigating the safety, and secondary endpoints of subretinal rAAV.sFLT-1 gene therapy in patients with active wet age-related macular degeneration (wAMD).

Methods: All patients (n=32), (ClinicalTrials.

Gene Therapy for Age-Related Macular Degeneration.

The purpose of this article was to evaluate safety and signals of efficacy of gene therapy with subretinal rAAV.sFlt-1 for wet age-related macular degeneration (wet AMD). A phase 1 dose-escalating single-center controlled unmasked human clinical trial was followed up by extension of the protocol to a phase 2A single-center trial.

Biomarkers for Diabetic Retinopathy - Could Endothelin 2 Be Part of the Answer?

Purpose: The endothelins are a family of three highly conserved and homologous vasoactive peptides that are expressed across all organ systems. Endothelin (Edn) dysregulation has been implicated in a number of pathophysiologies, including diabetes and diabetes-related complications. Here we examined Edn2 and endothelin receptor B (Endrb) expression in retinae of diabetic mouse models and measured serum Edn2 to assess its biomarker potential.

Gene therapy with recombinant adeno-associated vectors for neovascular age-related macular degeneration: 1 year follow-up of a phase 1 randomised clinical trial.

Background: Neovascular, or wet, age-related macular degeneration causes central vision loss and represents a major health problem in elderly people, and is currently treated with frequent intraocular injections of anti-VEGF protein. Gene therapy might enable long-term anti-VEGF therapy from a single treatment. We tested the safety of rAAV.

Molecular analysis of blood-retinal barrier loss in the Akimba mouse, a model of advanced diabetic retinopathy.

The molecular mechanisms of vascular leakage in diabetic macular edema and proliferative retinopathy are poorly understood, mainly due to the lack of reliable in vivo models. The Akimba (Ins2(Akita)VEGF(+/-)) mouse model combines retinal neovascularization with hyperglycemia, and in contrast to other models, displays the majority of signs of advanced clinical diabetic retinopathy (DR). To study the molecular mechanism that underlies the breakdown of the blood-retinal barrier (BRB) in diabetic macular edema and proliferative diabetic retinopathy, we investigated the retinal vasculature of Akimba and its parental mice Kimba (trVEGF029) and Akita (Ins2(Akita)).

Effect of vascular endothelial growth factor upregulation on retinal gene expression in the Kimba mouse.

Background:   The Kimba mouse carries a human vascular endothelial growth factor transgene causing retinal neovascularisation similar to that seen in diabetic retinopathy. Here, we examine the relationship between differential gene expression induced by vascular endothelial growth factor overexpression and the architectural changes that occur in the retinae of these mice.

Methods:   Retinal gene expression changes in juvenile and adult Kimba mice were assayed by microarray and compared with age-matched wild-type littermates.

In vivo monitoring of VEGF-induced retinal damage in the Kimba mouse model of retinal neovascularization.

Purpose: To monitor retinal and vascular changes associated with neovascularization, which were generated through photoreceptor-specific overexpression of human vascular endothelial growth factor (hVEGF), in transgenic trVEGF029 (Kimba) mice.

Materials And Methods: The Spectralis Heidelberg Retina Angiography and Optical Coherence Tomography (HRA+OCT) imaging device was used to track changes in the retina and retinal vasculature of Kimba mouse eyes (n = 32) and control C57Bl/6J mouse eyes (n = 20) at 4, 8, 12, 16, and 20 weeks of age.

Results: Retinal vascular leakage, focal dilated vessel, vessel tortuosity, attenuated vessel, venous beading, capillary dropout, retinal non-perfusion, neovascularization, and focal retinal detachment were observed in Kimba mouse eyes.

Characterization of a mouse model of hyperglycemia and retinal neovascularization.

One of the limitations of research into diabetic retinopathy is the lack of suitable animal models. To study how the two important factors--hyperglycemia and vascular endothelial growth factor--interact in diabetic retinopathy, the Akimba mouse (Ins2AkitaVEGF+/-) was generated by crossing the Akita mouse (Ins2Akita) with the Kimba mouse (VEGF+/+). C57Bl/6 and the parental and Akimba mouse lines were characterized by biometric measurements, histology, immunohistochemistry, and Spectralis Heidelberg retinal angiography and optical coherence tomography.

rAAV.sFlt-1 gene therapy achieves lasting reversal of retinal neovascularization in the absence of a strong immune response to the viral vector.

Purpose: To determine the efficacy of rAAV.sFlt-1-mediated gene therapy in a transgenic mouse model of retinal neovascularization (trVEGF029) and to assess whether rAAV.sFlt-1 administration generated any deleterious, long-lasting immune response that could affect efficacy.

Early vascular and neuronal changes in a VEGF transgenic mouse model of retinal neovascularization.

Purpose: To investigate early retinal changes in a vascular endothelial growth factor (VEGF) transgenic mouse (tr029VEGF; rhodopsin promoter) with long-term damage that mimics nonproliferative diabetic retinopathy (NPDR) and mild proliferative diabetic retinopathy (PDR).

Methods: Rhodopsin and VEGF expression was assessed up to postnatal day (P)28. Vascular and retinal changes were charted at P7 and P28 using sections and wholemounts stained with hematoxylin and eosin or isolectin IB4 Griffonia simplicifolia Samples were examined using light, fluorescence, and confocal microscopy.

VEGF differentially regulates transcription and translation of ZO-1alpha+ and ZO-1alpha- and mediates trans-epithelial resistance in cultured endothelial and epithelial cells.

Tight junctions (TJ) between retinal pigmented epithelial (RPE) and retinal endothelial cells maintain the outer and inner blood-retinal barrier, and the breakdown of these barriers is associated with retinal diseases. Vascular endothelial growth factor (VEGF) increases vascular permeability and is thought to be involved in age-related maculopathy. However, to date, little is known about the effect of VEGF on RPE cell junctions.

Long-term evaluation of AAV-mediated sFlt-1 gene therapy for ocular neovascularization in mice and monkeys.

Vascular endothelial growth factor (VEGF) is one of the major mediators of retinal ischemia-associated neovascularization. We have shown here that adeno-associated virus (AAV)-mediated expression of sFlt-1, a soluble form of the Flt-1 VEGF receptor, was maintained for up to 8 and 17 months postinjection in mice and in monkeys, respectively. The expression of sFlt-1 was associated with the long-term (8 months) regression of neovascular vessels in 85% of trVEGF029 eyes.

Recombinant adeno-associated virus type 2-mediated gene delivery into the knockout mouse eye results in limited rescue.

Background: Leber's congenital amaurosis (LCA) is a severe form of retinal dystrophy. Mutations in the RPE65 gene, which is abundantly expressed in retinal pigment epithelial (RPE) cells, account for approximately 10-15% of LCA cases. In this study we used the high turnover, and rapid breeding and maturation time of the knockout mice to assess the efficacy of using rAAV-mediated gene therapy to replace the disrupted RPE65 gene.

Predilection of the macular region to high incidence of choroidal neovascularization after intense laser photocoagulation in the monkey.

Objective: To determine the key factors for creating a high incidence model of choroidal neovascularization (CNV) in the monkey.

Methods: Intense laser photocoagulation was performed in 8 eyes of 4 monkeys using krypton red and green-yellow and Alcon frequency-doubled diode ophthalmic lasers. Eight to 13 lesions were delivered to an area between the temporal vascular arcades in each eye.

Impurity of recombinant adeno-associated virus type 2 affects the transduction characteristics following subretinal injection in the rat.

We recently reported that different purification methods of recombinant adeno-associated virus type 2 (rAAV2) affect the transduction characteristics following subretinal injection. In this study, we examined the roles of contaminant proteins from the HEK-293 cells and helper adenovirus, inactivation of helper adenovirus and cell stress induced by DNA-damaging agents in rAAV-mediated retinal transduction. Our results showed that contaminating factors/proteins resulting from the helper E1 deleted adenovirus are possibly responsible for efficient RPE transduction.