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Su ZZS, Ang BCH, Balne PK, Tun SBB, Htoon HM, Schmetterer L, Barathi VA, Agrawal R. Effect of anti-VEGF on retinal blood flow in diabetic mice using laser speckle flowgraphy. Acta Ophthalmol 2024. [PMID: 38572815 DOI: 10.1111/aos.16672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 03/07/2024] [Accepted: 03/12/2024] [Indexed: 04/05/2024]
Abstract
PURPOSE To assess intra- (repeatability) and inter-observer (reproducibility) variability of laser speckle flowgraphy (LSFG) for retinal blood flow (RBF) measurement in 20 eyes of wild type (C57BL/6J) mice and effect of intravitreal Aflibercept on RBF in optic nerve head (ONH) region of 10 eyes of Ins2 (Akita) diabetic mice. METHODS 'Mean blur rate (MBR)' was measured for all quadrants of tissue area (MT), vessel (MV) and total area (MA) of ONH region. Changes in MT were analysed at each timepoint. Repeatability was evaluated by measuring MBR variability without changing mouse head position, and reproducibility after resetting mouse head position by another operator. Coefficient of repeatability (CR) through Bland-Altman plot method coefficient of variation (COV) and Intraclass correlation coefficient (ICC) was calculated. Intravitreal Aflibercept (1 μg) was administered to Akita eyes and intraocular pressure (IOP) was measured using a tonometer at baseline, day 7, 14, 21 and 28 post-injection. Hurvich and Tsai's criterion was used. RESULTS Coefficient of repeatability values of repeatability and reproducibility for all quadrants were within limits of agreement. Reliability was excellent (ICC 0.98-0.99) and reproducibility was moderate to excellent (ICC 0.64-0.96). There was a non-significant IOP increase in all Akita eyes at Day 28 (p > 0.05), and significant increase in MT in all quadrants at Day 21 and superior, inferior and temporal quadrants at Day 28 (p < 0.05). CONCLUSION Laser speckle flowgraphy demonstrates excellent repeatability and moderate to excellent reproducibility in measuring RBF. Intravitreal Aflibercept injection results in a significant increase in MT up to 28 days post-injection without significant increase in IOP.
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Affiliation(s)
- Zheng Zhe Steven Su
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- Ministry of Health Holdings, Singapore, Singapore
| | - Bryan Chin Hou Ang
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore
- National Healthcare Group Eye Institute, Woodlands Health, Singapore, Singapore
- Ophthalmology, Mayo Clinic, Jacksonville, Florida, USA
| | - Praveen Kumar Balne
- College of Veterinary Medicine, University of Missouri, Columbia, Missouri, USA
| | - Sai Bo Bo Tun
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Hla Myint Htoon
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Leopold Schmetterer
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological University, Singapore, Singapore
- Department of Clinical Pharmacology, Medical University Vienna, Vienna, Austria
- Center for Medical Physics and Biomedical Engineering, Medical University Vienna, Vienna, Austria
- SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
- Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
| | - Veluchamy Amutha Barathi
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
| | - Rupesh Agrawal
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
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2
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Babu VS, Mallipatna A, Dudeja G, Shetty R, Nair AP, Tun SBB, Ho CEH, Chaurasia SS, Bhattacharya SS, Verma NK, Lakshminarayanan R, Guha N, Heymans S, Barathi VA, Ghosh A. Depleted hexokinase1 and lack of AMPKα activation favor OXPHOS-dependent energetics in retinoblastoma tumors. Transl Res 2023; 261:41-56. [PMID: 37419277 DOI: 10.1016/j.trsl.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 06/03/2023] [Accepted: 07/02/2023] [Indexed: 07/09/2023]
Abstract
Lack of retinoblastoma (Rb) protein causes aggressive intraocular retinal tumors in children. Recently, Rb tumors have been shown to have a distinctly altered metabolic phenotype, such as reduced expression of glycolytic pathway proteins alongside altered pyruvate and fatty acid levels. In this study, we demonstrate that loss of hexokinase 1(HK1) in tumor cells rewires their metabolism allowing enhanced oxidative phosphorylation-dependent energy production. We show that rescuing HK1 or retinoblastoma protein 1 (RB1) in these Rb cells reduced cancer hallmarks such as proliferation, invasion, and spheroid formation and increased their sensitivity to chemotherapy drugs. Induction of HK1 was accompanied by a metabolic shift of the cells to glycolysis and a reduction in mitochondrial mass. Cytoplasmic HK1 bound Liver Kinase B1 and phosphorylated AMP-activated kinase-α (AMPKα Thr172), thereby reducing mitochondria-dependent energy production. We validated these findings in tumor samples from Rb patients compared to age-matched healthy retinae. HK1 or RB1 expression in Rb-/- cells led to a reduction in their respiratory capacity and glycolytic proton flux. HK1 overexpression reduced tumor burden in an intraocular tumor xenograft model. AMPKα activation by AICAR also enhanced the tumoricidal effects of the chemotherapeutic drug topotecan in vivo. Therefore, enhancing HK1 or AMPKα activity can reprogram cancer metabolism and sensitize Rb tumors to lower doses of existing treatments, a potential therapeutic modality for Rb.
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Affiliation(s)
- Vishnu Suresh Babu
- GROW Research Laboratory, Narayana Nethralaya Foundation, Bangalore, India; Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - Ashwin Mallipatna
- Retinoblastoma Service, Narayana Nethralaya, Bangalore, Karnataka, India
| | - Gagan Dudeja
- Retinoblastoma Service, Narayana Nethralaya, Bangalore, Karnataka, India
| | - Rohit Shetty
- GROW Research Laboratory, Narayana Nethralaya Foundation, Bangalore, India
| | | | | | | | - Shyam S Chaurasia
- Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Shomi S Bhattacharya
- University College London, London, UK; GROW Research Laboratory, Narayana Nethralaya Foundation, Bangalore, India
| | - Navin Kumar Verma
- Lee Kong Chian School of Medicine, Nanyang Technological University Singapore, Singapore; Singapore Eye Research Institute, Singapore
| | | | - Nilanjan Guha
- Agilent Technologies India Pvt Ltd, New Delhi, Delhi, India
| | - Stephane Heymans
- Department of Cardiology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands; Department of Cardiovascular Sciences, Centre for Molecular and Vascular Biology, Leuven, Belgium
| | - Veluchamy Amutha Barathi
- Singapore Eye Research Institute, Singapore; The Ophthalmology and Visual Sciences ACP, Duke-NUS Medical School, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Arkasubhra Ghosh
- GROW Research Laboratory, Narayana Nethralaya Foundation, Bangalore, India.
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Tun SBB, Shepherdson E, Tay HG, Barathi VA. Sub-Retinal Delivery of Human Embryonic Stem Cell Derived Photoreceptor Progenitors in rd10 Mice. J Vis Exp 2023. [PMID: 37870304 DOI: 10.3791/65848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023] Open
Abstract
Regeneration of photoreceptor cells using human pluripotent stem cells is a promising therapy for the treatment of both hereditary and aging retinal diseases at advanced stages. We have shown human recombinant retina-specific laminin isoform matrix is able to support the differentiation of human embryonic stem cells (hESCs) to photoreceptor progenitors. In addition, sub-retinal injection of these cells has also shown partial restoration in the rd10 rodent and rabbit models. Sub-retinal injection is known to be an established method that has been used to deliver pharmaceutical compounds to the photoreceptor cells and retinal pigmented epithelial (RPE) layer of the eye due to its proximity to the target space. It has also been used to deliver adeno-associated viral vectors into the sub-retinal space to treat retinal diseases. The sub-retinal delivery of pharmaceutical compounds and cells in the murine model is challenging due to the constraint in the size of the murine eyeball. This protocol describes the detailed procedure for the preparation of hESC-derived photoreceptor progenitor cells for injection and the sub-retinal delivery technique of these cells in genetic retinitis pigmentosa mutant, rd10 mice. This approach allows cell therapy to the targeted area, in particular the outer nuclear layer of the retina, where diseases leading to photoreceptor degeneration occur.
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Affiliation(s)
- Sai Bo Bo Tun
- Singapore National Eye Centre, Singapore Eye Research Institute
| | | | - Hwee Goon Tay
- Centre for Vision Research, Duke-NUS Medical School; Ophthalmology and Visual Sciences Academic Clinical Program, DUKE-NUS Medical School;
| | - Veluchamy Amutha Barathi
- Singapore National Eye Centre, Singapore Eye Research Institute; Ophthalmology and Visual Sciences Academic Clinical Program, DUKE-NUS Medical School; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore;
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Tay HG, Andre H, Chrysostomou V, Adusumalli S, Guo J, Ren X, Tan WS, Tor JE, Moreno-Moral A, Plastino F, Bartuma H, Cai Z, Tun SBB, Barathi VA, Siew Wei GT, Grenci G, Chong LY, Holmgren A, Kvanta A, Crowston JG, Petretto E, Tryggvason K. Photoreceptor laminin drives differentiation of human pluripotent stem cells to photoreceptor progenitors that partially restore retina function. Mol Ther 2023; 31:825-846. [PMID: 36638800 PMCID: PMC10014235 DOI: 10.1016/j.ymthe.2022.12.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2022] [Revised: 07/12/2022] [Accepted: 12/21/2022] [Indexed: 01/14/2023] Open
Abstract
Blindness caused by advanced stages of inherited retinal diseases and age-related macular degeneration are characterized by photoreceptor loss. Cell therapy involving replacement with functional photoreceptor-like cells generated from human pluripotent stem cells holds great promise. Here, we generated a human recombinant retina-specific laminin isoform, LN523, and demonstrated the role in promoting the differentiation of human embryonic stem cells into photoreceptor progenitors. This chemically defined and xenogen-free method enables reproducible production of photoreceptor progenitors within 32 days. We observed that the transplantation into rd10 mice were able to protect the host photoreceptor outer nuclear layer (ONL) up to 2 weeks post transplantation as measured by full-field electroretinogram. At 4 weeks post transplantation, the engrafted cells were found to survive, mature, and associate with the host's rod bipolar cells. Visual behavioral assessment using the water maze swimming test demonstrated visual improvement in the cell-transplanted rodents. At 20 weeks post transplantation, the maturing engrafted cells were able to replace the loss of host ONL by extensive association with host bipolar cells and synapses. Post-transplanted rabbit model also provided congruent evidence for synaptic connectivity with the degenerated host retina. The results may pave the way for the development of stem cell-based therapeutics for retina degeneration.
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Affiliation(s)
- Hwee Goon Tay
- Centre for Vision Research, Duke-NUS Medical School, Singapore; Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore.
| | - Helder Andre
- Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Vicki Chrysostomou
- Centre for Vision Research, Duke-NUS Medical School, Singapore; Academic Clinical Program, Duke-NUS Medical School, Singapore
| | | | - Jing Guo
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore
| | - Xiaoyuan Ren
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Wei Sheng Tan
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore
| | - Jia En Tor
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore
| | - Aida Moreno-Moral
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore
| | - Flavia Plastino
- Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Hammurabi Bartuma
- Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Zuhua Cai
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore
| | - Sai Bo Bo Tun
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Veluchamy Amutha Barathi
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Gavin Tan Siew Wei
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Gianluca Grenci
- Mechanobiology Institute (MBI) and Department of Biomedical Engineering, NUS, Singapore
| | - Li Yen Chong
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore
| | - Arne Holmgren
- Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Anders Kvanta
- Department of Clinical Neuroscience, St. Erik Eye Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Jonathan Guy Crowston
- Centre for Vision Research, Duke-NUS Medical School, Singapore; Academic Clinical Program, Duke-NUS Medical School, Singapore; Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Enrico Petretto
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore
| | - Karl Tryggvason
- Cardiovascular and Metabolic Disorders Program, Duke-NUS Medical School, Singapore; Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden; Division of Nephrology, Department of Medicine, Duke University, Durham, NC, USA.
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5
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Tun SBB, Barathi VA. Akimba Proliferative Diabetic Retinopathy Model: Understanding Molecular Mechanism and Drug Screening for the Progression of Diabetic Retinopathy. Methods Mol Biol 2023; 2678:13-26. [PMID: 37326702 DOI: 10.1007/978-1-0716-3255-0_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
As the prevalence of diabetes has reached epidemic proportions worldwide, diabetic retinopathy incidence is increasing rapidly. An advanced diabetic retinopathy (DR) stage can lead to a sight-threatening form. There is growing evidence showing diabetes causes a range of metabolic changes that subsequently lead to pathological modifications in the retina and retinal blood vessels. To understand the complex mechanism of the pathophysiology of DR, a precise model is not readily available. By crossbreeding the Akita and Kimba strains, a suitable proliferative DR model was acquired. This new Akimba strain manifests marked hyperglycemia and vascular changes, which resemble the early and advanced stage of DR.Here, we describe the breeding method, colony screening for experiments, and imaging techniques widely used to investigate the DR progression in this model. We elaborate step-by-step protocols to set up and perform fundus, fluorescein angiography, optical coherence tomography, and optical coherence tomography-angiogram to study retinal structural changes and vascular abnormalities. In addition, we show a method to label the leukocytes with fluorescence and laser speckle flowgraphy to examine the inflammation in the retina and retinal vessel blood flow speed, respectively. Lastly, we describe electroretinogram to evaluate the functional aspect of the DR transformations.
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Affiliation(s)
- Sai Bo Bo Tun
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute, Singapore, Singapore
- Karolinska Institutet, Stockholm, Sweden
| | - Veluchamy Amutha Barathi
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute, Singapore, Singapore.
- ACP in Ophthalmology & Visual Sciences, DUKE-NUS Graduate Medical School, Singapore, Singapore.
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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6
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Tun SBB, Chua M, Tan GSW, Leibiger I, Ali Y, Barathi VA, Berggren PO. Local Dexamethasone Administration Delays Allogeneic Islet Graft Rejection in the Anterior Chamber of the Eye of Non-Human Primates. Cell Transplant 2022; 31:9636897221098038. [PMID: 35603580 PMCID: PMC9125106 DOI: 10.1177/09636897221098038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pancreatic islet transplantation into the anterior chamber of the eye (ACE) has been shown to improve glycemic control and metabolic parameters of diabetes in both murine and primate models. This novel transplantation site also allows the delivery of therapeutic agents, such as immunosuppressive drugs, locally to prevent islet graft rejection and circumvent unwanted systemic side effects. Local intravitreal administration of micronized dexamethasone implant was performed prior to allogeneic islet transplantation into the ACEs of non-human primates. Two study groups were observed namely allogeneic graft without immunosuppression (n = 4 eyes) and allogeneic graft with local immunosuppression (n = 8 eyes). Survival of islet grafts and dexamethasone concentration in the ACE were assessed in parallel for 24 weeks. Allogeneic islet grafts with local dexamethasone treatment showed significantly better survival than those with no immunosuppression (median survival time- 15 weeks vs 3 weeks, log-rank test p<0.0001). Around 73% of the grafts still survived at week 10 with a single local dexamethasone implant, where the control group showed no graft survival. Dexamethasone treated islet grafts revealed a good functional response to high glucose stimulation despite there was a transient suppression of insulin secretion from week 8 to 12. Our findings show a significant improvement of allografts survival in the ACE with local dexamethasone treatment. These results highlight the feasibility of local administration of pharmacological compounds in the ACE to improve islet graft survival and function. By eliminating the need for systemic immunosuppression, these findings may impact clinical islet transplantation in the treatment of diabetes, and the ACE may serve as a novel therapeutic islet transplantation site with high potential for local pharmacological intervention.
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Affiliation(s)
- Sai Bo Bo Tun
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute, Singapore
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Minni Chua
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute, Singapore
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Gavin Siew Wei Tan
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, DUKE-NUS Medical School, Singapore
| | - Ingo Leibiger
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Yusuf Ali
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Veluchamy Amutha Barathi
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute, Singapore
- Ophthalmology and Visual Sciences Academic Clinical Program, DUKE-NUS Medical School, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Per-Olof Berggren
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute, Singapore
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL, USA
- Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
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7
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Fenner BJ, Tan TE, Barathi AV, Tun SBB, Yeo SW, Tsai ASH, Lee SY, Cheung CMG, Chan CM, Mehta JS, Teo KYC. Gene-Based Therapeutics for Inherited Retinal Diseases. Front Genet 2022; 12:794805. [PMID: 35069693 PMCID: PMC8782148 DOI: 10.3389/fgene.2021.794805] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/14/2021] [Indexed: 12/14/2022] Open
Abstract
Inherited retinal diseases (IRDs) are a heterogenous group of orphan eye diseases that typically result from monogenic mutations and are considered attractive targets for gene-based therapeutics. Following the approval of an IRD gene replacement therapy for Leber's congenital amaurosis due to RPE65 mutations, there has been an intensive international research effort to identify the optimal gene therapy approaches for a range of IRDs and many are now undergoing clinical trials. In this review we explore therapeutic challenges posed by IRDs and review current and future approaches that may be applicable to different subsets of IRD mutations. Emphasis is placed on five distinct approaches to gene-based therapy that have potential to treat the full spectrum of IRDs: 1) gene replacement using adeno-associated virus (AAV) and nonviral delivery vectors, 2) genome editing via the CRISPR/Cas9 system, 3) RNA editing by endogenous and exogenous ADAR, 4) mRNA targeting with antisense oligonucleotides for gene knockdown and splicing modification, and 5) optogenetic approaches that aim to replace the function of native retinal photoreceptors by engineering other retinal cell types to become capable of phototransduction.
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Affiliation(s)
- Beau J Fenner
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-NUS Graduate Medical School, Ophthalmology and Visual Sciences Academic Clinical Programme, Singapore, Singapore
| | - Tien-En Tan
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-NUS Graduate Medical School, Ophthalmology and Visual Sciences Academic Clinical Programme, Singapore, Singapore
| | | | - Sai Bo Bo Tun
- Singapore Eye Research Institute, Singapore, Singapore
| | - Sia Wey Yeo
- Singapore Eye Research Institute, Singapore, Singapore
| | - Andrew S H Tsai
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-NUS Graduate Medical School, Ophthalmology and Visual Sciences Academic Clinical Programme, Singapore, Singapore
| | - Shu Yen Lee
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-NUS Graduate Medical School, Ophthalmology and Visual Sciences Academic Clinical Programme, Singapore, Singapore
| | - Chui Ming Gemmy Cheung
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-NUS Graduate Medical School, Ophthalmology and Visual Sciences Academic Clinical Programme, Singapore, Singapore
| | - Choi Mun Chan
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-NUS Graduate Medical School, Ophthalmology and Visual Sciences Academic Clinical Programme, Singapore, Singapore
| | - Jodhbir S Mehta
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-NUS Graduate Medical School, Ophthalmology and Visual Sciences Academic Clinical Programme, Singapore, Singapore.,School of Material Science and Engineering, Nanyang Technological University, Singapore, Singapore.,Yong Loo Lin School of Medicine, Department of Ophthalmology, National University of Singapore, Singapore, Singapore
| | - Kelvin Y C Teo
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-NUS Graduate Medical School, Ophthalmology and Visual Sciences Academic Clinical Programme, Singapore, Singapore
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8
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Tan TE, Fenner BJ, Barathi VA, Tun SBB, Wey YS, Tsai ASH, Su X, Lee SY, Cheung CMG, Wong TY, Mehta JS, Teo KYC. Gene-Based Therapeutics for Acquired Retinal Disease: Opportunities and Progress. Front Genet 2021; 12:795010. [PMID: 34950193 PMCID: PMC8688942 DOI: 10.3389/fgene.2021.795010] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/16/2021] [Indexed: 12/22/2022] Open
Abstract
Acquired retinal diseases such as age-related macular degeneration and diabetic retinopathy rank among the leading causes of blindness and visual loss worldwide. Effective treatments for these conditions are available, but often have a high treatment burden, and poor compliance can lead to disappointing real-world outcomes. Development of new treatment strategies that provide more durable treatment effects could help to address some of these unmet needs. Gene-based therapeutics, pioneered for the treatment of monogenic inherited retinal disease, are being actively investigated as new treatments for acquired retinal disease. There are significant advantages to the application of gene-based therapeutics in acquired retinal disease, including the presence of established therapeutic targets and common pathophysiologic pathways between diseases, the lack of genotype-specificity required, and the larger potential treatment population per therapy. Different gene-based therapeutic strategies have been attempted, including gene augmentation therapy to induce in vivo expression of therapeutic molecules, and gene editing to knock down genes encoding specific mediators in disease pathways. We highlight the opportunities and unmet clinical needs in acquired retinal disease, review the progress made thus far with current therapeutic strategies and surgical delivery techniques, and discuss limitations and future directions in the field.
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Affiliation(s)
- Tien-En Tan
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore
| | - Beau James Fenner
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore
| | - Veluchamy Amutha Barathi
- Singapore Eye Research Institute, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sai Bo Bo Tun
- Singapore Eye Research Institute, Singapore, Singapore
| | - Yeo Sia Wey
- Singapore Eye Research Institute, Singapore, Singapore
| | - Andrew Shih Hsiang Tsai
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore
| | - Xinyi Su
- Singapore Eye Research Institute, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.,Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology and Research (ASTAR), Singapore, Singapore.,Department of Ophthalmology, National University Hospital, Singapore, Singapore
| | - Shu Yen Lee
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore
| | - Chui Ming Gemmy Cheung
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore
| | - Tien Yin Wong
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore
| | - Jodhbir Singh Mehta
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore
| | - Kelvin Yi Chong Teo
- Singapore National Eye Centre, Singapore, Singapore.,Singapore Eye Research Institute, Singapore, Singapore.,Duke-National University of Singapore Medical School, Singapore, Singapore
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9
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Liu YV, Konar G, Aziz K, Tun SBB, Hua CHE, Tan B, Tian J, Luu CD, Barathi VA, Singh MS. Localized Structural and Functional Deficits in a Nonhuman Primate Model of Outer Retinal Atrophy. Invest Ophthalmol Vis Sci 2021; 62:8. [PMID: 34643661 PMCID: PMC8525844 DOI: 10.1167/iovs.62.13.8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Purpose Cell-based therapy development for geographic atrophy (GA) in age-related macular degeneration (AMD) is hampered by the paucity of models of localized photoreceptor and retinal pigment epithelium (RPE) degeneration. We aimed to characterize the structural and functional deficits in a laser-induced nonhuman primate model, including an analysis of the choroid. Methods Macular laser photocoagulation was applied in four macaques. Fundus photography, optical coherence tomography (OCT), dye angiography, and OCT-angiography were conducted over 4.5 months, with histological correlation. Longitudinal changes in spatially resolved macular dysfunction were measured using multifocal electroretinography (MFERG). Results Lesion features, depending on laser settings, included photoreceptor layer degeneration, inner retinal sparing, skip lesions, RPE elevation, and neovascularization. The intralesional choroid was degenerated. The normalized mean MFERG amplitude within lesions was consistently lower than control regions (0.94 ± 0.35 vs. 1.10 ± 0.27, P = 0.032 at month 1, 0.67 ± 0.22 vs. 0.83 ± 0.15, P = 0.0002 at month 2, and 0.97 ± 0.31 vs. 1.20 ± 0.21, P < 0.0001 at month 3.5). The intertest variation of mean MFERG amplitudes in rings 1 to 5 ranged from 13.0% to 26.0% in normal eyes. Conclusions Laser application in this model caused localized outer retinal, RPE, and choriocapillaris loss. Localized dysfunction was apparent by MFERG in the first month after lesion induction. Correlative structure-function testing may be useful for research on the functional effects of stem cell-based therapy for GA. MFERG amplitude data should be interpreted in the context of relatively high intertest variability of the rings that correspond to the central macula. Sustained choroidal insufficiency may limit long-term subretinal graft viability in this model.
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Affiliation(s)
- Ying V Liu
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Gregory Konar
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Kanza Aziz
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
| | - Sai Bo Bo Tun
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Singapore
| | - Candice Ho Ee Hua
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Singapore
| | - Bingyao Tan
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore
| | - Jing Tian
- Department of Biostatistics, Johns Hopkins University Bloomberg School of Public Health, Baltimore, United States
| | - Chi D Luu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Victoria, Australia.,Ophthalmology, Department of Surgery, University of Melbourne, Victoria, Australia
| | - Veluchamy A Barathi
- Singapore Eye Research Institute, Singapore National Eye Center, Singapore, Singapore.,Academic Clinical Program in Ophthalmology, Duke-NUS Graduate Medical School, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Mandeep S Singh
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States
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10
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Cheung CMG, Teo KYC, Tun SBB, Busoy JM, Barathi VA, Spaide RF. Correlation of choriocapillaris hemodynamic data from dynamic indocyanine green and optical coherence tomography angiography. Sci Rep 2021; 11:15580. [PMID: 34341447 PMCID: PMC8329180 DOI: 10.1038/s41598-021-95270-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 07/15/2021] [Indexed: 11/15/2022] Open
Abstract
To investigate the correlation between posterior pole choroidal blood flow evaluated with digital subtraction indocyanine green angiography and enface optical coherence tomography angiography (OCTA). Imaging in animal study. The anatomy of 2 cynomogulus monkeys was studied. Each monkey was given a 0.75 mg/kg injection of indocyanine green in the saphenous vein. The dynamic angiographic filling sequence was recorded at 15 frames per second using the Heidelberg Spectralis. After image registration, sequential frame subtraction was used to image the dye front moving through the choroid. The OCTA was obtained by frame averaging nine separate choriocapillaris slab flow images obtained from the Zeiss Plex Elite 9000. Posterior pole choriocapillaris filling pattern in relation to the choriocapillaris anatomy as imaged by OCTA. In the posterior pole, the choriocapillaris fills in the pattern of discrete units with variable sizes and shapes. The cycle of dye filling begins in the peripapillary area and progresses toward the periphery in a wavelike manner. This filling pattern repeats in a cyclical manner, consistent with the cardiac cycle. OCTA shows a uniform mesh of vessels. While OCTA shows a uniform meshwork appearance of the choriocapillaris, the dynamic dye angiography suggests an irregular configuration of functional units partitioned by pressure gradients as opposed to structural boundaries. Disturbance of local perfusion pressure within choroidal vasculature may result in abnormal flow patterns, which could be evaluated in the clinic using commercially available equipment.
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Affiliation(s)
- Chui Ming Gemmy Cheung
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore. .,Ophthalmology and Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore.
| | - Kelvin Yi Chong Teo
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore.,Save Sight Institute, Discipline of Ophthalmology, Sydney Medical School, The University of Sydney, Sydney, NSW, Australia
| | - Sai Bo Bo Tun
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Joanna Marie Busoy
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Veluchamy A Barathi
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore
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11
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Cheong KX, Barathi VA, Teo KYC, Chakravarthy U, Tun SBB, Busoy JM, Ho CEH, Agrawal R, Takahashi K, Cheung CMG. Choroidal and Retinal Changes After Systemic Adrenaline and Photodynamic Therapy in Non-Human Primates. Invest Ophthalmol Vis Sci 2021; 62:25. [PMID: 33729474 PMCID: PMC7980042 DOI: 10.1167/iovs.62.3.25] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Purpose To determine the tomographic, angiographic, and histologic changes in the choroid and retina of cynomolgus monkeys after systemic adrenaline and verteporfin photodynamic therapy (vPDT). Methods Six cynomolgus monkeys (12 eyes) were treated with vPDT only (n = 2), adrenaline only for eight weeks (n = 2), adrenaline for eight weeks with vPDT at week 4 (n = 4), and adrenaline for 12 weeks and vPDT at week 8 (n = 4). Spectral-domain optical coherence tomography, angiography, and autofluorescence were performed at baseline and every 14 days thereafter until 28 days after adrenaline therapy or vPDT. Choroid parameters included choroidal thickness (CT) changes and structural changes using semiautomated image binarization. Histology with light and electron microscopy was performed. Results Adrenaline resulted in subfoveal CT increase at week 4 compared with baseline (3.4%, P = 0.010), with further increase at week 8 (3.9%, P = 0.007). This correlated with choroidal luminal area increase (16.0% at week 8 compared with baseline, P = 0.030). Outer retinal changes included subretinal fluid, ellipsoid zone (EZ) disruption, photoreceptor elongation, and sub/intraretinal bright dots. Hypocyanescent spots surrounded by leakage was observed. Histology showed dilated choroidal vessels, intracytoplasmic vacuoles, and retinal pigment epithelium (RPE) enlarged basal infoldings. The vPDT decreased subfoveal CT at four weeks after vPDT (−7.5%, P = 0.007). This correlated with choroidal stromal area decrease (−18.0%, P < 0.010). Within the treatment spot, there was outer retinal atrophy, EZ disruption, irregular RPE thickening, intense hypoautofluorescence, hyperfluorescence, and hypocyanescence. On histology, there were outer retina, RPE, and choroid changes. Conclusions Adrenaline induces choroidal vessel dilation and CT increase. The vPDT decreases CT because of a reduction in choroidal stromal component.
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Affiliation(s)
- Kai Xiong Cheong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Veluchamy Amutha Barathi
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.,Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | | | - Usha Chakravarthy
- School of Medicine, Dentistry and Biomedical Sciences, Queens University Belfast, Belfast, United Kingdom
| | - Sai Bo Bo Tun
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Joanna Marie Busoy
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Candice Ee Hua Ho
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Rupesh Agrawal
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.,Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore.,National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore.,Moorfields Eye Hospital, NHS Foundation Trust, London, United Kingdom
| | - Kanji Takahashi
- Department of Ophthalmology, Kansai Medical University, Hirakata, Osaka, Japan
| | - Chui Ming Gemmy Cheung
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.,Ophthalmology & Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore
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12
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Cheung CMG, Teo KYC, Tun SBB, Busoy JM, Veluchamy AB, Spaide RF. Differential reperfusion patterns in retinal vascular plexuses following increase in intraocular pressure an OCT angiography study. Sci Rep 2020; 10:16505. [PMID: 33020568 PMCID: PMC7536233 DOI: 10.1038/s41598-020-73585-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 09/18/2020] [Indexed: 11/09/2022] Open
Abstract
To describe patterns of reperfusion in the superficial vascular plexus (SVP), deep capillary plexus (DCP) and choriocapillaris (CC) as detected on optical coherence tomography (OCTA) in cynomogulus macaque monkey model following increase in intraocular pressure by an intravitreal injection. Animal imaging study. Two cynomogulus macaque monkeys. A 100 µL intravitreal injection (IVI) of saline was given in one eye of each monkey. Serial OCTA using a Zeiss Plex Elite 9000 was used to evaluate reperfusion patterns within the SCP, DCP, and CC. OCTA evidence of perfusion. Pulsation of the central retinal artery was detected after the intraocular pressure was elevated to 98 and ≥ 99 mmHg from IVI. Episodic flow within the SVP arterioles and venules and poor visualization of flow in capillaries was noted during the initial phase of elevated pressure. As the pressure declined, the flow signal within the DCP appeared initially as dots, which progressed laterally to loops which form capillary vortex configuration. Recovery of flow within the SVP and CC appeared sooner than in the DCP. At 40 min after the injection, well after the intraocular pressure normalized, the retinal and choriocapillaris vascular perfusion showed focal defects in every layer. Compared with pre-injection images, vessel density in the DCP was 68.8% and 78.6% of baseline in monkey 1 and monkey 2, respectively. In contrast vessel density in the SVP recovered to 84.2% and 88.9% of baseline. Increases in intraocular pressure from IVI have the potential to affect every layer of blood flow in the fundus. After nominal return of intraocular pressure, focal defects in flow persisted, which may result in longer term damage to the retina.
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Affiliation(s)
- Chui Ming Gemmy Cheung
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore. .,Ophthalmology and Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore.
| | - Kelvin Yi Chong Teo
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program (Eye ACP), Duke-NUS Medical School, Singapore, Singapore.,University of Sydney, Sydney, Australia
| | - Sai Bo Bo Tun
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Joanna Marie Busoy
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore
| | - Amutha Barathi Veluchamy
- Singapore Eye Research Institute, Singapore National Eye Centre, 11 Third Hospital Ave, Singapore, 168751, Singapore
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13
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Chan ASY, Tun TA, Allen JC, Lynn MN, Tun SBB, Barathi VA, Girard MJA, Aung T, Aihara M. Longitudinal assessment of optic nerve head changes using optical coherence tomography in a primate microbead model of ocular hypertension. Sci Rep 2020; 10:14709. [PMID: 32895414 PMCID: PMC7477239 DOI: 10.1038/s41598-020-71555-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 08/19/2020] [Indexed: 11/16/2022] Open
Abstract
In humans, the longitudinal characterisation of early optic nerve head (ONH) damage in ocular hypertension (OHT) is difficult as patients with glaucoma usually have structural ONH damage at the time of diagnosis. Previous studies assessed glaucomatous ONH cupping by measuring the anterior lamina cribrosa depth (LCD) and minimal rim width (MRW) using optical coherence tomography (OCT). In this study, we induced OHT by repeated intracameral microbead injections in 16 cynomolgus primates (10 unilateral; 6 bilateral) and assessed the structural changes of the ONH longitudinally to observe early changes. Elevated intraocular pressure (IOP) in OHT eyes was maintained for 7 months and serial OCT measurements were performed during this period. The mean IOP was significantly elevated in OHT eyes when compared to baseline and compared to the control eyes. Thinner MRW and deeper LCD values from baseline were observed in OHT eyes with the greatest changes seen between month 1 and month 2 of OHT. Both the mean and maximum IOP values were significant predictors of MRW and LCD changes, although the maximum IOP was a slightly better predictor. We believe that this model could be useful to study IOP-induced early ONH structural damage which is important for understanding glaucoma pathogenesis.
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Affiliation(s)
- Anita S Y Chan
- Singapore Eye Research Institute and Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore. .,Department of Ophthalmology, University of Tokyo, Tokyo, Japan.
| | - Tin Aung Tun
- Singapore Eye Research Institute and Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.,Ophthalmic Engineering & Innovation Laboratory (OEIL), Singapore Eye Research Institute, Singapore, Singapore
| | | | - Myoe Naing Lynn
- Singapore Eye Research Institute and Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore
| | - Sai Bo Bo Tun
- Singapore Eye Research Institute and Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore
| | - Veluchamy Amutha Barathi
- Singapore Eye Research Institute and Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.,Duke-NUS Medical School, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Michaël J A Girard
- Singapore Eye Research Institute and Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.,Ophthalmic Engineering & Innovation Laboratory (OEIL), Singapore Eye Research Institute, Singapore, Singapore
| | - Tin Aung
- Singapore Eye Research Institute and Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, 168751, Singapore.,Duke-NUS Medical School, Singapore, Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Makoto Aihara
- Department of Ophthalmology, University of Tokyo, Tokyo, Japan
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14
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Tun SBB, Chua M, Hasan R, Köhler M, Zheng X, Ali Y, Abdulreda MH, Juntti-Berggren L, Barathi VA, Berggren PO. Islet Transplantation to the Anterior Chamber of the Eye-A Future Treatment Option for Insulin-Deficient Type-2 Diabetics? A Case Report from a Nonhuman Type-2 Diabetic Primate. Cell Transplant 2020; 29:963689720913256. [PMID: 32264703 PMCID: PMC7444223 DOI: 10.1177/0963689720913256] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Replacement of the insulin-secreting beta cells through transplantation of pancreatic islets to the liver is a promising treatment for type-1 diabetes. However, low oxygen tension, shear stress, and the induction of inflammation lead to significant islet dysfunction and loss. The anterior chamber of the eye (ACE) has gained considerable interest and represents an alternative therapeutic islet transplantation site because of its accessibility, high oxygen tension, and immune-privileged milieu. We have previously demonstrated the feasibility of intraocular islet transplant in mouse and nonhuman primate models of type-1 diabetes and are now assessing its efficacy on glucose homeostasis in a nonhuman primate model of type-2 diabetes. We transplanted allogeneic donor islets (1,500 islet equivalents/kg) into the anterior chamber of one eye in a cynomolgus monkey with high-fat-diet-induced type-2 diabetes. Repeated examinations of the anterior and posterior segments of both eyes were done to monitor the engrafted islets and assess the overall ocular health. Fasting blood glucose level, blood biochemistry, and other metabolic parameters were routinely evaluated to determine the function of the islet graft and diabetes status. The transplanted islets were rapidly engrafted onto the iris and became vascularized 1 month after transplantation. We did not detect changes in intraocular pressure, cataract formation, ophthalmitis, or retinal vessel deformation. A significant lower fasting blood glucose level was observed while the graft was in place, and the transplantation reverts the progression of diabetes. The metabolic markers, hemoglobin A1C and fructosamine, demonstrated improvement following islet transplantation. As a conclusion, intraocular islet transplantation in one eye of a cynomolgus monkey with type-2 diabetes improved its overall plasma glucose homeostasis, as evidenced by short-term measures and long-term metabolic markers. These results further support the future application of the ACE as an alternative site for clinical islet transplants in the context of type-2 diabetes.
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Affiliation(s)
- Sai Bo Bo Tun
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute (SERI), Singapore.,The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Minni Chua
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Riasat Hasan
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Martin Köhler
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Xiaofeng Zheng
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute (SERI), Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Yusuf Ali
- Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Midhat H Abdulreda
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL, USA.,Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Lisa Juntti-Berggren
- The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden
| | - Veluchamy A Barathi
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute (SERI), Singapore.,Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Ophthalmology and Visual Sciences Academic Clinical Program, DUKE-NUS Graduate Medical School, Singapore
| | - Per-Olof Berggren
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute (SERI), Singapore.,The Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, Stockholm, Sweden.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL, USA.,Department of Surgery, University of Miami Miller School of Medicine, Miami, FL, USA
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15
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Regula JT, Lundh von Leithner P, Foxton R, Barathi VA, Chui Ming GC, Tun SBB, Wey YS, Iwata D, Dostalek M, Moelleken J, Stubenrauch KG, Nogoceke E, Widmer G, Strassburger P, Koss MJ, Klein C, Shima DT, Hartmann G. Targeting key angiogenic pathways with a bispecific CrossMAb optimized for neovascular eye diseases. EMBO Mol Med 2019; 11:emmm.201910666. [PMID: 31040127 DOI: 10.15252/emmm.201910666] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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16
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Teo KYC, Lee SY, Barathi AV, Tun SBB, Tan L, Constable IJ. Surgical Removal of Internal Limiting Membrane and Layering of AAV Vector on the Retina Under Air Enhances Gene Transfection in a Nonhuman Primate. ACTA ACUST UNITED AC 2018; 59:3574-3583. [DOI: 10.1167/iovs.18-24333] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- Kelvin Yi Chong Teo
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
| | - Shu Yen Lee
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
| | - Amutha Veluchamy Barathi
- Translational Pre-clinical Model Platform, Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Sai Bo Bo Tun
- Translational Pre-clinical Model Platform, Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
| | - Licia Tan
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
- Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
| | - Ian Jeffery Constable
- Centre of Ophthalmology and Visual Science (incorporating Lions Eye Institute), The University of Western Australia, Perth, Western Australia
- Department of Ophthalmology, Sir Charles Gairdner Hospital, Perth, Western Australia
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17
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Agrawal R, Tun SBB, Balne PK, Zhu HY, Khandelwal N, Barathi VA. Fluorescein Labeled Leukocytes for in vivo Imaging of Retinal Vascular Inflammation and Infiltrating Leukocytes in Laser-Induced Choroidal Neovascularization Model. Ocul Immunol Inflamm 2018; 28:7-13. [PMID: 29470933 DOI: 10.1080/09273948.2018.1429637] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Purpose: To study the effect of anti-VEGF treatment on retinal inflammation in a laser-induced CNV rodent model.Methods: Leukocytes labeled with 1% sodium fluorescein were injected into the laser-induced CNV (wild type C57BL/6) mice at days 4 (baseline), 7, 14, and 19. At baseline intravitreally 3 mice received 1× PBS, and 3 mice received anti-VEGF. FFA, OCT, and SLO were performed at each time point to assess the CNV pathophysiology and inflammatory response.Results: Fluorescein leakage, SRF, and leukocyte infiltration were observed at baseline in both the groups before injection. From days 7 to 19, leukocyte infiltration and SRF were noted in the 1× PBS group, but limited or no SRF and leukocyte infiltration was observed in the anti-VEGF group.Conclusions: Leukocyte infiltration was established as an in vivo imaging inflammatory marker and along with FFA and OCT showed response to anti-VEGF therapy in laser-induced CNV model.
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Affiliation(s)
- Rupesh Agrawal
- Translational Preclinical Model Platform, Singapore Eye Research Institute, Singapore.,National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Sai Bo Bo Tun
- Translational Preclinical Model Platform, Singapore Eye Research Institute, Singapore
| | - Praveen Kumar Balne
- Translational Preclinical Model Platform, Singapore Eye Research Institute, Singapore
| | - Hong-Yuan Zhu
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore
| | - Neha Khandelwal
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore
| | - Veluchamy A Barathi
- Translational Preclinical Model Platform, Singapore Eye Research Institute, Singapore.,Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Ophthalmology Academic Clinical Research Program, DUKE-NUS Graduate Medical School, Singapore
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18
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Agrawal R, Balne PK, Tun SBB, Sia Wey Y, Khandelwal N, Barathi VA. Fluorescent Dye Labeling of Erythrocytes and Leukocytes for Studying the Flow Dynamics in Mouse Retinal Circulation. J Vis Exp 2017. [PMID: 28715402 DOI: 10.3791/55495] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The retinal and choroidal blood flow dynamics may provide insight into the pathophysiology and sequelae of various ocular diseases, such as glaucoma, diabetic retinopathy, age-related macular degeneration (AMD) and other ocular inflammatory conditions. It may also help to monitor the therapeutic responses in the eye. The proper labeling of the blood cells, coupled with live-cell imaging of the labeled cells, allows for the investigation of the flow dynamics in the retinal and choroidal circulation. Here, we describe the standardized protocols of 1.5% indocyanine green (ICG) and 1% sodium fluorescein labeling of mice erythrocytes and leukocytes, respectively. Scanning laser ophthalmoscopy (SLO) was applied to visualize the labeled cells in the retinal circulation of C57BL/6J mice (wild type). Both methods demonstrated distinct fluorescently labeled cells in the mouse retinal circulation. These labeling methods can have wider applications in various ocular disease models.
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Affiliation(s)
- Rupesh Agrawal
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital; Singapore Eye Research Institute (SERI), Singapore National Eye Center; School of Material Science and Engineering, Nanyang Technological University;
| | | | - Sai Bo Bo Tun
- Singapore Eye Research Institute (SERI), Singapore National Eye Center
| | - Yeo Sia Wey
- Singapore Eye Research Institute (SERI), Singapore National Eye Center
| | - Neha Khandelwal
- National Healthcare Group Eye Institute, Tan Tock Seng Hospital
| | - Veluchamy A Barathi
- Singapore Eye Research Institute (SERI), Singapore National Eye Center; Department of Ophthalmology, Yong Loo Lin School of Medicine, National University Health Systems, National University of Singapore; Ophthalmology Academic Clinical Research Program, DUKE-NUS Graduate Medical School;
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19
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Su X, Tan QSW, Parikh BH, Tan A, Mehta MN, Sia Wey Y, Tun SBB, Li LJ, Han XY, Wong TY, Hunziker W, Luu CD, Owada Y, Barathi VA, Zhang SS, Chaurasia SS. Characterization of Fatty Acid Binding Protein 7 (FABP7) in the Murine Retina. Invest Ophthalmol Vis Sci 2017; 57:3397-408. [PMID: 27367508 DOI: 10.1167/iovs.15-18542] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To characterize the mouse retina lacking fatty acid binding protein (FABP7-/-). METHODS Immunohistochemistry (IHC) was performed in 8-week-old mice to localize FABP7 in the retina. Retinal thickness was measured using image-guided spectral-domain optical coherence topography images. Electroretinography was carried out to assess retinal function. Fundus photography and fundus fluorescein angiography were performed on FABP7-/- and littermate wild-type (WT) mice, and retinal vascular changes were calculated using Singapore I Vessel Assessment (SIVA) analysis. Blood glucose levels were measured in the 8-week-old WT and FABP7-/- mice. In addition, retina was processed for trypsin digestion and retinal flat mounts for isolectin staining. Transcript levels of FABP7, VEGF, GFAP, and Na+K+ATPase were quantified using real-time PCR, and protein expression was analyzed by IHC and Western blot. RESULTS Fatty acid binding protein 7 is expressed in the inner nuclear layer, outer plexiform layer, and photoreceptor inner segments. No significant difference in retinal thickness and ERG responses was observed between FABP7-deficient and WT retinas. FABP7-/- mice have significantly decreased retinal venular caliber retinal arteriolar fractal dimension compared with WT littermates. FABP7-/- mice showed significant increased areas of fluorescein leakage in the retina. FABP7-/- mice exhibited elevated high blood glucose levels compared with WT mice. Trypsin digested FABP7-/- mice retina showed increased acellular strands and endothelial cell drop outs, and reduced microvasculature branching compared with WT retina. FABP7-/- mice retina also have increased GFAP and VEGF expression. CONCLUSIONS Fatty acid binding protein 7 is expressed in the retina and might play an important role in maintaining retinal vasculature.
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Affiliation(s)
- Xinyi Su
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore 2Institute of Molecular Cell Biology, SIPRAD (IMCB-SERI Program in Retinal Angiogenic Diseases), A*STAR, Singapore 3Department of Ophthalmology, Yong Loo Lin School of Medicine, Nat
| | - Queenie S W Tan
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore 2Institute of Molecular Cell Biology, SIPRAD (IMCB-SERI Program in Retinal Angiogenic Diseases), A*STAR, Singapore
| | - Bhav H Parikh
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore 2Institute of Molecular Cell Biology, SIPRAD (IMCB-SERI Program in Retinal Angiogenic Diseases), A*STAR, Singapore
| | - Alison Tan
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore 2Institute of Molecular Cell Biology, SIPRAD (IMCB-SERI Program in Retinal Angiogenic Diseases), A*STAR, Singapore
| | - Milan N Mehta
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore 2Institute of Molecular Cell Biology, SIPRAD (IMCB-SERI Program in Retinal Angiogenic Diseases), A*STAR, Singapore
| | - Yeo Sia Wey
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore
| | - Sai Bo Bo Tun
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore
| | - Ling-Jun Li
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore
| | - Xiao-Yan Han
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Tien Y Wong
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore 3Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 4Ophthalmology and Visual Sciences Academic Clinical Program, DUKE-NUS Gra
| | - Walter Hunziker
- Institute of Molecular Cell Biology, SIPRAD (IMCB-SERI Program in Retinal Angiogenic Diseases), A*STAR, Singapore 5Department of Physiology, National University of Singapore, Singapore
| | - Chi D Luu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Melbourne, Australia 7Department of Surgery (Ophthalmology), University of Melbourne, Melbourne, Australia
| | - Yuji Owada
- Yamaguchi University, Department of Organ Anatomy, Ube, Japan
| | - Veluchamy A Barathi
- Singapore Eye Research Institute Singapore National Eye Centre, Singapore 3Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 4Ophthalmology and Visual Sciences Academic Clinical Program, DUKE-NUS Gra
| | - Samuel S Zhang
- Department of Neural and Behavioral Sciences, Penn State College of Medicine, Penn State University, Hershey, Pennsylvania, United States
| | - Shyam S Chaurasia
- Ocular Immunology and Angiogenesis Lab, Department of Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States
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Regula JT, Lundh von Leithner P, Foxton R, Barathi VA, Gemmy Cheung CM, Bo Tun SB, Wey YS, Iwata D, Dostalek M, Moelleken J, Stubenrauch KG, Nogoceke E, Widmer G, Strassburger P, Koss MJ, Klein C, Shima DT, Hartmann G. Targeting key angiogenic pathways with a bispecific CrossMAb optimized for neovascular eye diseases. EMBO Mol Med 2017; 9:985. [PMID: 28533211 DOI: 10.15252/emmm.201707895] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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21
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Regula JT, Lundh von Leithner P, Foxton R, Barathi VA, Cheung CMG, Bo Tun SB, Wey YS, Iwata D, Dostalek M, Moelleken J, Stubenrauch KG, Nogoceke E, Widmer G, Strassburger P, Koss MJ, Klein C, Shima DT, Hartmann G. Targeting key angiogenic pathways with a bispecific CrossMAb optimized for neovascular eye diseases. EMBO Mol Med 2016; 8:1265-1288. [PMID: 27742718 PMCID: PMC5090659 DOI: 10.15252/emmm.201505889] [Citation(s) in RCA: 161] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Anti‐angiogenic therapies using biological molecules that neutralize vascular endothelial growth factor‐A (VEGF‐A) have revolutionized treatment of retinal vascular diseases including age‐related macular degeneration (AMD). This study reports preclinical assessment of a strategy to enhance anti‐VEGF‐A monotherapy efficacy by targeting both VEGF‐A and angiopoietin‐2 (ANG‐2), a factor strongly upregulated in vitreous fluids of patients with retinal vascular disease and exerting some of its activities in concert with VEGF‐A. Simultaneous VEGF‐A and ANG‐2 inhibition was found to reduce vessel lesion number, permeability, retinal edema, and neuron loss more effectively than either agent alone in a spontaneous choroidal neovascularization (CNV) model. We describe the generation of a bispecific domain‐exchanged (crossed) monoclonal antibody (CrossMAb; RG7716) capable of binding, neutralizing, and depleting VEGF‐A and ANG‐2. RG7716 showed greater efficacy than anti‐VEGF‐A alone in a non‐human primate laser‐induced CNV model after intravitreal delivery. Modification of RG7716's FcRn and FcγR binding sites disabled the antibodies' Fc‐mediated effector functions. This resulted in increased systemic, but not ocular, clearance. These properties make RG7716 a potential next‐generation therapy for neovascular indications of the eye.
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Affiliation(s)
- Jörg T Regula
- Roche Pharma Research and Early Development, Roche Innovation Center München, Penzberg, Germany
| | - Peter Lundh von Leithner
- Department of Ocular Biology and Therapeutics, UCL London Institute of Ophthalmology, London, UK
| | - Richard Foxton
- Department of Ocular Biology and Therapeutics, UCL London Institute of Ophthalmology, London, UK.,Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Veluchamy A Barathi
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute The Academia, Singapore, Singapore.,The Ophthalmology & Visual Sciences Academic Clinical Program, DUKE-NUS Graduate Medical School, Singapore, Singapore
| | - Chui Ming Gemmy Cheung
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute The Academia, Singapore, Singapore
| | - Sai Bo Bo Tun
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute The Academia, Singapore, Singapore
| | - Yeo Sia Wey
- Translational Pre-Clinical Model Platform, Singapore Eye Research Institute The Academia, Singapore, Singapore
| | - Daiju Iwata
- Department of Ocular Biology and Therapeutics, UCL London Institute of Ophthalmology, London, UK
| | - Miroslav Dostalek
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Jörg Moelleken
- Roche Pharma Research and Early Development, Roche Innovation Center München, Penzberg, Germany
| | - Kay G Stubenrauch
- Roche Pharma Research and Early Development, Roche Innovation Center München, Penzberg, Germany
| | - Everson Nogoceke
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Gabriella Widmer
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Pamela Strassburger
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Michael J Koss
- Department of Ophthalmology, Goethe University, Frankfurt am Main, Germany.,Department of Ophthalmology, Ruprecht Karls University, Heidelberg, Germany
| | - Christian Klein
- Roche Pharma Research and Early Development, Roche Innovation Center Zürich, F. Hoffmann-La Roche Ltd, Zürich, Switzerland
| | - David T Shima
- Department of Ocular Biology and Therapeutics, UCL London Institute of Ophthalmology, London, UK
| | - Guido Hartmann
- Roche Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
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