Optimal Humanized Scg3-Neutralizing Antibodies for Anti-Angiogenic Therapy of Diabetic Retinopathy.

Secretogranin III (Scg3) is a diabetic retinopathy (DR)-restricted angiogenic factor identified in preclinical studies as a target for DR therapy. Previously, our group generated and characterized ML49.3, an anti-Scg3 monoclonal antibody (mAb) which we then converted into an EBP2 humanized antibody Fab fragment (hFab) with potential for clinical application. We also generated anti-Scg3 mT4 mAb and related EBP3 hFab. In this study, to identify the preferred hFab for DR therapy, we compared all four antibodies for binding, neutralizing and therapeutic activities in vitro and in vivo. Octet binding kinetics analyses revealed that ML49.3 mAb, EBP2 hFab, mT4 mAb and EBP3 hFab have Scg3-binding affinities of 35, 8.7, 0.859 and 0.116 nM, respectively. Both anti-Scg3 EBP2 and EBP3 hFabs significantly inhibited Scg3-induced proliferation and migration of human umbilical vein endothelial cells in vitro, and alleviated DR vascular leakage and choroidal neovascularization with high efficacy. Paired assays in DR mice revealed that intravitreally injected EBP3 hFab is 26.4% and 10.3% more effective than EBP2 hFab and aflibercept, respectively, for ameliorating DR leakage. In conclusion, this study confirms the markedly improved binding affinities of hFabs compared to mAbs and further identifies EBP3 hFab as the preferred antibody to develop for anti-Scg3 therapy.

Clinical presentation, treatment, and genetic and histopathological analysis of juvenile cataracts and secondary glaucoma in a rhesus macaque (Macaca mulatta).

This report describes the clinical and histological findings, genetic study, and treatment in a 1.3-year-old rhesus macaque with bilateral cataracts and unilateral secondary glaucoma. Intravitreal injection of gentamicin decreased the intraocular pressure from 56 to <2 mm Hg. A putative genetic cause of the cataracts was not identified.

Purtscher-like retinopathy: A rare presentation of hematopoietic stem cell transplant-associated thrombotic microangiopathy.

Hematopoietic stem cell transplant (HSCT)-associated (TA) thrombotic microangiopathy (TMA) is an acquired disorder and a potentially life-threatening complication after allogeneic HSCT. TA-TMA causes endothelial damage and results in micro-thrombi in capillaries and arterioles. Early detection and treatment of complications associated with TA-TMA might improve outcomes. Purtscher-like retinopathy (PLR) is associated with micro-thrombi that occlude the retinal arteries and cause retinal injury. PLR has been associated with multiple entities, including HUS and TTP, but has not previously been described in the setting of TA-TMA. Here, we describe an 18-year-old male who underwent a mismatched unrelated donor HSCT for relapsed acute lymphoblastic leukemia. The patient was diagnosed with TA-TMA based on standard defined criteria. He presented with acute onset of blurred vision with findings of multiple white retinal patches, retinal hemorrhages, and macular edema, thought initially to be hypertensive retinopathy. However, on further evaluation using fluorescein angiography and optical coherence tomography, the diagnosis was determined to be PLR. The patient was treated with intravitreal steroid injections (triamcinolone acetonide) with dramatic improvement of vision. The aim of this report is to make clinicians aware of PLR as a potential ocular complication associated with TA-TMA and that prompt intervention might reverse visual impairment.

Gene transfer for the treatment of neovascular ocular disease (an American Ophthalmological Society thesis).

PURPOSE: As vasoproliferative diseases account for a substantial fraction of worldwide blindness and share the activation of the angiogenic pathway as a common etiology, the expression of antiangiogenic proteins offers a promising means of treatment. This study was designed to develop viral vectors, harboring angiostatic genes, for the study and treatment of experimental proliferative ocular disease. A variety of methods (in vitro, ex vivo tissue, and in vivo) were employed to model the process of proliferation and test the effectiveness of these reagents. METHODS: Antiangiogenic genes included single genes as well as hybrid genes that fused the active elements of different genes. Genes studied included the soluble vascular endothelial growth factor receptor (sKDR), soluble neuropilin (sNRP-1), tissue inhibitor of metalloproteinase-1 (TIMP-1), plasminogen gene fragments (Kringle 1-3, 1-4, and 1-5), and soluble receptors for advanced glycosylation end products (sRAGE) genes, as well as the Endo:Ang, MIG:IP10, and Endo:Kringle5 fusion genes. All genes were cloned into a lentiviral vector system and were used to produce replication deficient lentiviral particles. These viral particles were used to transduce a variety of ocular cells and tissues to test viral transfer efficiency and transgene expression. In vivo systems were employed to explore the potential of these genes as antiangiogenic agents in models of corneal and retinal neovascular disease. RESULTS: Recombinant lentiviral particles, capable of transducing cell lines germane to eye disease (ocular endothelial, epithelial, and fibroblast cells), were successfully produced. These vectors were demonstrated to be effective in long-term transformation of cells and tissues. In vivo experiments confirmed that at least three different potentially angiostatic genes were successful in aborting the angiogenic process in the ocular models tested. CONCLUSIONS: Lentiviral vectors are a viable means to deliver angiostatic genes to tissues of the eye. Some angiostatic genes appear to have a stronger and longer-lasting effect than others in modulating the angiogenic pathway.