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DeBoer CMT, Rasmussen DK, Franco JA, Mahajan VB. Emerging Oral Pharmaceuticals for Dry Age-Related Macular Degeneration: Mechanism of Action, Current Clinical Status, and Future Directions. Ophthalmic Surg Lasers Imaging Retina 2024; 55:528-534. [PMID: 38917394 DOI: 10.3928/23258160-20240430-02] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/27/2024]
Abstract
Dry age-related macular degeneration (AMD) has been historically managed with lifestyle modifications, monitoring for conversion to wet AMD, and vitamins. Recently there has been a flurry of research focused on discovering new targets to prevent worsening of dry AMD. In 2023, the US Food and Drug Administration approved the first two intravitreal complement inhibitors to slow the rate of geographic atrophy progression. However, serial intravitreal injections for a chronic progressive disease are burdensome for patients and have procedural risks. Therefore, there is significant research to discover novel oral medications to manage dry AMD. Several oral medications are currently in phase 2 and 3 clinical trials for dry AMD, whereas others have had recent readouts on their clinical trials and efficacy. The purpose of this review is to describe the therapeutic pathways currently being investigated and to provide an update on the clinical status of novel oral medications for the management of dry AMD. [Ophthalmic Surg Lasers Imaging Retina 2024;55:528-534.].
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2
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Fujinami K, Waheed N, Laich Y, Yang P, Fujinami-Yokokawa Y, Higgins JJ, Lu JT, Curtiss D, Clary C, Michaelides M. Stargardt macular dystrophy and therapeutic approaches. Br J Ophthalmol 2024; 108:495-505. [PMID: 37940365 PMCID: PMC10958310 DOI: 10.1136/bjo-2022-323071] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Accepted: 10/06/2023] [Indexed: 11/10/2023]
Abstract
Stargardt macular dystrophy (Stargardt disease; STGD1; OMIM 248200) is the most prevalent inherited macular dystrophy. STGD1 is an autosomal recessive disorder caused by multiple pathogenic sequence variants in the large ABCA4 gene (OMIM 601691). Major advances in understanding both the clinical and molecular features, as well as the underlying pathophysiology, have culminated in many completed, ongoing and planned human clinical trials of novel therapies.The aims of this concise review are to describe (1) the detailed phenotypic and genotypic characteristics of the disease, multimodal imaging findings, natural history of the disease, and pathogenesis, (2) the multiple avenues of research and therapeutic intervention, including pharmacological, cellular therapies and diverse types of genetic therapies that have either been investigated or are under investigation and (3) the exciting novel therapeutic approaches on the translational horizon that aim to treat STGD1 by replacing the entire 6.8 kb ABCA4 open reading frame.
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Affiliation(s)
- Kaoru Fujinami
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, NHO Tokyo Medical Center, Meguro-ku, Tokyo, Japan
- Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
| | - Nadia Waheed
- Department of Ophthalmology, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Yannik Laich
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
- Eye Center, Medical Center, University of Freiburg Faculty of Medicine, Freiburg, Germany
| | - Paul Yang
- Oregon Health and Science University Casey Eye Institute, Portland, Oregon, USA
| | - Yu Fujinami-Yokokawa
- Laboratory of Visual Physiology, Division of Vision Research, National Institute of Sensory Organs, NHO Tokyo Medical Center, Meguro-ku, Tokyo, Japan
- Institute of Ophthalmology, University College London, London, UK
- Department of Health Policy and Management, Keio University School of Medicine Graduate School of Medicine, Shinjuku-ku, Tokyo, Japan
| | | | - Jonathan T Lu
- SalioGen Therapeutics Inc, Lexington, Massachusetts, USA
| | - Darin Curtiss
- Applied Genetic Technologies Corporation, Alachua, Florida, USA
| | - Cathryn Clary
- SalioGen Therapeutics Inc, Lexington, Massachusetts, USA
| | - Michel Michaelides
- Institute of Ophthalmology, University College London, London, UK
- Moorfields Eye Hospital NHS Foundation Trust, London, UK
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3
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Nadeem A, Malik IA, Shariq F, Afridi EK, Taha M, Raufi N, Naveed AK, Iqbal J, Habte A. Advancements in the treatment of geographic atrophy: focus on pegcetacoplan in age-related macular degeneration. Ann Med Surg (Lond) 2023; 85:6067-6077. [PMID: 38098608 PMCID: PMC10718344 DOI: 10.1097/ms9.0000000000001466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 10/23/2023] [Indexed: 12/17/2023] Open
Abstract
Geographic atrophy (GA) is a progressive form of age-related macular degeneration characterized by the degeneration of retinal pigment epithelial cells and photoreceptor death. The dysregulation of the complement cascade has been implicated in GA progression. This review provides a comprehensive overview of the pathophysiology of age-related macular degeneration and GA, discusses current therapeutic options, and focuses on the recent breakthrough drug, pegcetacoplan (SYFOVRE). Pegcetacoplan is a complement inhibitor that selectively targets the C3 complement protein, effectively modulating complement activation. Clinical trials, including the OAKS and DERBY studies, have demonstrated the efficacy of SYFOVRE in reducing the growth of GA lesions compared to placebo. The FDA approval of SYFOVRE as the first and only definitive therapy for GA marks a significant milestone in the management of this debilitating condition. The review also explores potential future treatment strategies, including immune-modulating agents and ocular gene therapy. While SYFOVRE offers new hope for GA patients, further research is needed to evaluate its long-term benefits, safety profile, and optimal treatment regimens.
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Affiliation(s)
| | | | | | | | | | - Nahid Raufi
- Department of Medicine, Kabul Medical University, Afghanistan
| | - Ahmed K. Naveed
- Department of Medicine, Dow University of Health Sciences, Karachi
| | - Javed Iqbal
- King Edward Medical University Lahore, Pakistan
| | - Alexander Habte
- Department of Surgery, Assab Military Hospital, Assab, Eritrea
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4
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Borchert GA, Shamsnajafabadi H, Hu ML, De Silva SR, Downes SM, MacLaren RE, Xue K, Cehajic-Kapetanovic J. The Role of Inflammation in Age-Related Macular Degeneration-Therapeutic Landscapes in Geographic Atrophy. Cells 2023; 12:2092. [PMID: 37626902 PMCID: PMC10453093 DOI: 10.3390/cells12162092] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 07/28/2023] [Accepted: 08/11/2023] [Indexed: 08/27/2023] Open
Abstract
Age-related macular degeneration (AMD) is the leading cause of vision loss and visual impairment in people over 50 years of age. In the current therapeutic landscape, intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapies have been central to the management of neovascular AMD (also known as wet AMD), whereas treatments for geographic atrophy have lagged behind. Several therapeutic approaches are being developed for geographic atrophy with the goal of either slowing down disease progression or reversing sight loss. Such strategies target the inflammatory pathways, complement cascade, visual cycle or neuroprotective mechanisms to slow down the degeneration. In addition, retinal implants have been tried for vision restoration and stem cell therapies for potentially a dual purpose of slowing down the degeneration and restoring visual function. In particular, therapies focusing on the complement pathway have shown promising results with the FDA approved pegcetacoplan, a complement C3 inhibitor, and avacincaptad pegol, a complement C5 inhibitor. In this review, we discuss the mechanisms of inflammation in AMD and outline the therapeutic landscapes of atrophy AMD. Improved understanding of the various pathway components and their interplay in this complex neuroinflammatory degeneration will guide the development of current and future therapeutic options, such as optogenetic therapy.
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Affiliation(s)
- Grace A. Borchert
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK
| | - Hoda Shamsnajafabadi
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK
| | - Monica L. Hu
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK
| | - Samantha R. De Silva
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Susan M. Downes
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Robert E. MacLaren
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Kanmin Xue
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University NHS Foundation Trust, Oxford OX3 9DU, UK
| | - Jasmina Cehajic-Kapetanovic
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, Oxford University, Oxford OX3 9DU, UK
- Oxford Eye Hospital, Oxford University NHS Foundation Trust, Oxford OX3 9DU, UK
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5
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Bassetto M, Zaluski J, Li B, Zhang J, Badiee M, Kiser PD, Tochtrop GP. Tuning the Metabolic Stability of Visual Cycle Modulators through Modification of an RPE65 Recognition Motif. J Med Chem 2023; 66:8140-8158. [PMID: 37279401 PMCID: PMC10824489 DOI: 10.1021/acs.jmedchem.3c00461] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In the eye, the isomerization of all-trans-retinal to 11-cis-retinal is accomplished by a metabolic pathway termed the visual cycle that is critical for vision. RPE65 is the essential trans-cis isomerase of this pathway. Emixustat, a retinoid-mimetic RPE65 inhibitor, was developed as a therapeutic visual cycle modulator and used for the treatment of retinopathies. However, pharmacokinetic liabilities limit its further development including: (1) metabolic deamination of the γ-amino-α-aryl alcohol, which mediates targeted RPE65 inhibition, and (2) unwanted long-lasting RPE65 inhibition. We sought to address these issues by more broadly defining the structure-activity relationships of the RPE65 recognition motif via the synthesis of a family of novel derivatives, which were tested in vitro and in vivo for RPE65 inhibition. We identified a potent secondary amine derivative with resistance to deamination and preserved RPE65 inhibitory activity. Our data provide insights into activity-preserving modifications of the emixustat molecule that can be employed to tune its pharmacological properties.
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Affiliation(s)
- Marco Bassetto
- Department of Physiology and Biophysics, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
- Research Service, VA Long Beach Healthcare System, Long Beach, California 90822, United States
| | - Jordan Zaluski
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Bowen Li
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Jianye Zhang
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
| | - Mohsen Badiee
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Philip D Kiser
- Department of Physiology and Biophysics, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
- Department of Ophthalmology, Gavin Herbert Eye Institute, Center for Translational Vision Research, School of Medicine, University of California - Irvine, Irvine, California 92697, United States
- Department of Clinical Pharmacy Practice, School of Pharmacy and Pharmaceutical Sciences, University of California - Irvine, Irvine, California 92697, United States
- Research Service, VA Long Beach Healthcare System, Long Beach, California 90822, United States
| | - Gregory P Tochtrop
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
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6
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Jiang X, Mahroo OA. Human retinal dark adaptation tracked in vivo with the electroretinogram: insights into processes underlying recovery of cone- and rod-mediated vision. J Physiol 2022; 600:4603-4621. [PMID: 35612091 PMCID: PMC9796346 DOI: 10.1113/jp283105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Accepted: 05/04/2022] [Indexed: 01/02/2023] Open
Abstract
The substantial time taken for regaining visual sensitivity (dark adaptation) following bleaching exposures has been investigated for over a century. Psychophysical studies yielded the classic biphasic curve representing recovery of cone-driven and rod-driven vision. The electroretinogram (ERG) permits direct assessment of recovery at the level of the retina (photoreceptors, bipolar cells), with the first report over 70 years ago. Over the last two decades, ERG studies of dark adaptation have generated insights into underlying physiological processes. After large bleaches, rod photoreceptor circulating current, estimated from the rod-isolated bright-flash ERG a-wave, takes 30 min to recover, indicating that products of bleaching, thought to be free opsin (unbound to 11-cis-retinal), continue to activate phototransduction, shutting off rod circulating current. In contrast, cone current, assessed with cone-driven bright-flash ERG a-waves, recovers within 100 ms following similar exposures, suggesting that free opsin is less able to shut off cone current. The cone-driven dim-flash a-wave can be used to track recovery of cone photopigment, showing regeneration is 'rate-limited' rather than first order. Recoveries of the dim-flash ERG b-wave are consistent also with rate-limited rod photopigment regeneration (where free opsin, desensitising the visual system as an 'equivalent background', is removed by rate-limited delivery of 11-cis-retinal). These findings agree with psychophysical and retinal densitometry studies, although there are unexplained points of divergence. Post-bleach ERG recovery has been explored in age-related macular degeneration and in trials of visual cycle inhibitors for retinal diseases. ERG tracking of dark adaptation may prove useful in future clinical contexts.
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Affiliation(s)
- Xiaofan Jiang
- Institute of OphthalmologyUniversity College LondonLondonUK,Retinal and Genetics ServicesMoorfields Eye HospitalLondonUK,Section of OphthalmologyKing's College LondonLondonUK,Department of Twin Research and Genetic EpidemiologyKing's College London, St Thomas’ Hospital CampusLondonUK
| | - Omar A. Mahroo
- Institute of OphthalmologyUniversity College LondonLondonUK,Retinal and Genetics ServicesMoorfields Eye HospitalLondonUK,Section of OphthalmologyKing's College LondonLondonUK,Department of Twin Research and Genetic EpidemiologyKing's College London, St Thomas’ Hospital CampusLondonUK,PhysiologyDevelopment and NeuroscienceUniversity of CambridgeCambridgeUK
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7
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The novel visual cycle inhibitor (±)-RPE65-61 protects retinal photoreceptors from light-induced degeneration. PLoS One 2022; 17:e0269437. [PMID: 36227868 PMCID: PMC9560169 DOI: 10.1371/journal.pone.0269437] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 05/23/2022] [Indexed: 11/25/2022] Open
Abstract
The visual cycle refers to a series of biochemical reactions of retinoids in ocular tissues and supports the vision in vertebrates. The visual cycle regenerates visual pigments chromophore, 11-cis-retinal, and eliminates its toxic byproducts from the retina, supporting visual function and retinal neuron survival. Unfortunately, during the visual cycle, when 11-cis-retinal is being regenerated in the retina, toxic byproducts, such as all-trans-retinal and bis-retinoid is N-retinylidene-N-retinylethanolamine (A2E), are produced, which are proposed to contribute to the pathogenesis of the dry form of age-related macular degeneration (AMD). The primary biochemical defect in Stargardt disease (STGD1) is the accelerated synthesis of cytotoxic lipofuscin bisretinoids, such as A2E, in the retinal pigment epithelium (RPE) due to mutations in the ABCA4 gene. To prevent all-trans-retinal-and bisretinoid-mediated retinal degeneration, slowing down the retinoid flow by modulating the visual cycle with a small molecule has been proposed as a therapeutic strategy. The present study describes RPE65-61, a novel, non-retinoid compound, as an inhibitor of RPE65 (a key enzyme in the visual cycle), intended to modulate the excessive activity of the visual cycle to protect the retina from harm degenerative diseases. Our data demonstrated that (±)-RPE65-61 selectively inhibited retinoid isomerase activity of RPE65, with an IC50 of 80 nM. Furthermore, (±)-RPE65-61 inhibited RPE65 via an uncompetitive mechanism. Systemic administration of (±)-RPE65-61 in mice resulted in slower chromophore regeneration after light bleach, confirming in vivo target engagement and visual cycle modulation. Concomitant protection of the mouse retina from high-intensity light damage was also observed. Furthermore, RPE65-61 down-regulated the cyclic GMP-AMP synthase stimulator of interferon genes (cGAS-STING) pathway, decreased the inflammatory factor, and attenuated retinal apoptosis caused by light-induced retinal damage (LIRD), which led to the preservation of the retinal function. Taken together, (±)-RPE65-61 is a potent visual cycle modulator that may provide a neuroprotective therapeutic benefit for patients with STGD and AMD.
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8
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Fabre M, Mateo L, Lamaa D, Baillif S, Pagès G, Demange L, Ronco C, Benhida R. Recent Advances in Age-Related Macular Degeneration Therapies. Molecules 2022; 27:molecules27165089. [PMID: 36014339 PMCID: PMC9414333 DOI: 10.3390/molecules27165089] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 08/03/2022] [Accepted: 08/04/2022] [Indexed: 11/16/2022] Open
Abstract
Age-related macular degeneration (AMD) was described for the first time in the 1840s and is currently the leading cause of blindness for patients over 65 years in Western Countries. This disease impacts the eye’s posterior segment and damages the macula, a retina section with high levels of photoreceptor cells and responsible for the central vision. Advanced AMD stages are divided into the atrophic (dry) form and the exudative (wet) form. Atrophic AMD consists in the progressive atrophy of the retinal pigment epithelium (RPE) and the outer retinal layers, while the exudative form results in the anarchic invasion by choroidal neo-vessels of RPE and the retina. This invasion is responsible for fluid accumulation in the intra/sub-retinal spaces and for a progressive dysfunction of the photoreceptor cells. To date, the few existing anti-AMD therapies may only delay or suspend its progression, without providing cure to patients. However, in the last decade, an outstanding number of research programs targeting its different aspects have been initiated by academics and industrials. This review aims to bring together the most recent advances and insights into the mechanisms underlying AMD pathogenicity and disease evolution, and to highlight the current hypotheses towards the development of new treatments, i.e., symptomatic vs. curative. The therapeutic options and drugs proposed to tackle these mechanisms are analyzed and critically compared. A particular emphasis has been given to the therapeutic agents currently tested in clinical trials, whose results have been carefully collected and discussed whenever possible.
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Affiliation(s)
- Marie Fabre
- Institut de Chimie de Nice UMR 7272, Université Côte d’Azur, CNRS, 06108 Nice, France
| | - Lou Mateo
- Institut de Chimie de Nice UMR 7272, Université Côte d’Azur, CNRS, 06108 Nice, France
| | - Diana Lamaa
- CiTCoM, UMR 8038 CNRS, Faculté de Pharmacie, Université de Paris Cité, 4, Avenue de l’Observatoire, 75006 Paris, France
| | - Stéphanie Baillif
- Ophthalmology Department, University Hospital of Nice, 30 Avenue De La Voie Romaine, 06000 Nice, France
| | - Gilles Pagès
- Institute for Research on Cancer and Aging (IRCAN), UMR 7284 and INSERM U 1081, Université Côte d’Azur, CNRS 28 Avenue de Valombrose, 06107 Nice, France
| | - Luc Demange
- Institut de Chimie de Nice UMR 7272, Université Côte d’Azur, CNRS, 06108 Nice, France
- CiTCoM, UMR 8038 CNRS, Faculté de Pharmacie, Université de Paris Cité, 4, Avenue de l’Observatoire, 75006 Paris, France
- Correspondence: (L.D.); (C.R.); (R.B.)
| | - Cyril Ronco
- Institut de Chimie de Nice UMR 7272, Université Côte d’Azur, CNRS, 06108 Nice, France
- Correspondence: (L.D.); (C.R.); (R.B.)
| | - Rachid Benhida
- Institut de Chimie de Nice UMR 7272, Université Côte d’Azur, CNRS, 06108 Nice, France
- Department of Chemical and Biochemical Sciences-Green Process Engineering (CBS-GPE), Mohamed VI Polytechnic University (UM6P), Benguerir 43150, Morocco
- Correspondence: (L.D.); (C.R.); (R.B.)
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Neuroprotection for Age-Related Macular Degeneration. OPHTHALMOLOGY SCIENCE 2022; 2:100192. [PMID: 36570623 PMCID: PMC9767822 DOI: 10.1016/j.xops.2022.100192] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 06/24/2022] [Accepted: 06/28/2022] [Indexed: 12/27/2022]
Abstract
Age-related macular degeneration (AMD) is a leading cause of blindness worldwide. Early to intermediate AMD is characterized by the accumulation of lipid- and protein-rich drusen. Late stages of the disease are characterized by the development of choroidal neovascularization, termed "exudative" or "neovascular AMD," or retinal pigment epithelium (RPE) cell and photoreceptor death, termed "geographic atrophy" (GA) in advanced nonexudative AMD. Although we have effective treatments for exudative AMD in the form of anti-VEGF agents, they have no role for patients with GA. Neuroprotection strategies have emerged as a possible way to slow photoreceptor degeneration and vision loss in patients with GA. These approaches include reduction of oxidative stress, modulation of the visual cycle, reduction of toxic molecules, inhibition of pathologic protein activity, prevention of cellular apoptosis or programmed necrosis (necroptosis), inhibition of inflammation, direct activation of neurotrophic factors, delivery of umbilical tissue-derived cells, and RPE replacement. Despite active investigation in this area and significant promise based on preclinical studies, many clinical studies have not yielded successful results. We discuss selected past and current neuroprotection trials for AMD, highlight the lessons learned from these past studies, and discuss our perspective regarding remaining questions that must be answered before neuroprotection can be successfully applied in the field of AMD research.
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Key Words
- AD, Alzheimer disease
- ALA, alpha lipoic acid
- AMD, age-related macular degeneration
- AREDS, Age-Related Eye Disease Study
- AREDS2, Age-Related Eye Disease Study 2
- Age-related macular degeneration
- CFH, complement factor H
- CNTF, ciliary neurotrophic factor
- GA, geographic atrophy
- HTRA1, high-temperature requirement A1
- IOP, intraocular pressure
- Neuroprotection
- RBP, retinol-binding protein
- RGC, retinal ganglion cell
- RIPK3, receptor-interacting serine/threonine-protein kinase 3
- ROS, reactive oxygen species
- RPE, retinal pigment epithelium
- Retinal degeneration
- VA, visual acuity
- iPSC, induced pluripotent stem cell
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Pinilla I, Maneu V, Campello L, Fernández-Sánchez L, Martínez-Gil N, Kutsyr O, Sánchez-Sáez X, Sánchez-Castillo C, Lax P, Cuenca N. Inherited Retinal Dystrophies: Role of Oxidative Stress and Inflammation in Their Physiopathology and Therapeutic Implications. Antioxidants (Basel) 2022; 11:antiox11061086. [PMID: 35739983 PMCID: PMC9219848 DOI: 10.3390/antiox11061086] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2022] [Revised: 05/24/2022] [Accepted: 05/26/2022] [Indexed: 12/13/2022] Open
Abstract
Inherited retinal dystrophies (IRDs) are a large group of genetically and clinically heterogeneous diseases characterized by the progressive degeneration of the retina, ultimately leading to loss of visual function. Oxidative stress and inflammation play fundamental roles in the physiopathology of these diseases. Photoreceptor cell death induces an inflammatory state in the retina. The activation of several molecular pathways triggers different cellular responses to injury, including the activation of microglia to eliminate debris and recruit inflammatory cells from circulation. Therapeutical options for IRDs are currently limited, although a small number of patients have been successfully treated by gene therapy. Many other therapeutic strategies are being pursued to mitigate the deleterious effects of IRDs associated with oxidative metabolism and/or inflammation, including inhibiting reactive oxygen species’ accumulation and inflammatory responses, and blocking autophagy. Several compounds are being tested in clinical trials, generating great expectations for their implementation. The present review discusses the main death mechanisms that occur in IRDs and the latest therapies that are under investigation.
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Affiliation(s)
- Isabel Pinilla
- Aragón Health Research Institute (IIS Aragón), 50009 Zaragoza, Spain
- Department of Ophthalmology, Lozano Blesa, University Hospital, 50009 Zaragoza, Spain
- Department of Surgery, University of Zaragoza, 50009 Zaragoza, Spain
- Correspondence: (I.P.); (V.M.)
| | - Victoria Maneu
- Department of Optics, Pharmacology and Anatomy, University of Alicante, 03690 Alicante, Spain;
- Alicante Institute for Health and Biomedical Research (ISABIAL), 03010 Alicante, Spain; (P.L.); (N.C.)
- Correspondence: (I.P.); (V.M.)
| | - Laura Campello
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Laura Fernández-Sánchez
- Department of Optics, Pharmacology and Anatomy, University of Alicante, 03690 Alicante, Spain;
| | - Natalia Martínez-Gil
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Oksana Kutsyr
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Xavier Sánchez-Sáez
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Carla Sánchez-Castillo
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Pedro Lax
- Alicante Institute for Health and Biomedical Research (ISABIAL), 03010 Alicante, Spain; (P.L.); (N.C.)
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
| | - Nicolás Cuenca
- Alicante Institute for Health and Biomedical Research (ISABIAL), 03010 Alicante, Spain; (P.L.); (N.C.)
- Department of Physiology, Genetics and Microbiology, University of Alicante, 03690 Alicante, Spain; (L.C.); (N.M.-G.); (O.K.); (X.S.-S.); (C.S.-C.)
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11
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Velaga SB, Nittala MG, Hariri A, Sadda SR. Correlation between Fundus Autofluorescence and En Face Optical Coherence Tomography Measurements of Geographic Atrophy. Ophthalmol Retina 2022; 6:676-683. [PMID: 35338026 DOI: 10.1016/j.oret.2022.03.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Revised: 03/15/2022] [Accepted: 03/17/2022] [Indexed: 10/18/2022]
Abstract
PURPOSE To evaluate the correlation between fundus autofluorescence (FAF) and en face spectral-domain optical coherence tomography (SDOCT) measurements of geographic atrophy (GA) associated with age-related macular degeneration (AMD). DESIGN Retrospective, cross-sectional study. PARTICIPANTS 270 eyes from 172 subjects with GA associated with AMD. METHODS Subjects with atrophic AMD with both fundus autofluorescence (FAF; Heidelberg HRA + Spectralis) and dense volume (128 B-scans over 6x6mm) spectral domain optical coherence tomography (SDOCT; Cirrus OCT) imaging were included in this retrospective analysis. The borders of all areas of definite decreased autofluorescence (DDAF) corresponding to GA were manually outlined on FAF images by certified graders at the Doheny Image Reading Center (DIRC) using validated planimetric grading tools. GA was also delineated automatically from en face OCT (at the level of the choroid) using instrument software (Cirrus v.6.2), and segmentation errors were manually corrected prior to computation of GA area. FAF and SDOCT derived measurements were correlated. MAIN OUTCOME MEASURES Correlation between SD-OCT and FAF measurements of GA area. RESULTS The mean GA area measured from FAF images was 8.1 ± 5.04 mm2, compared with an automated, uncorrected SDOCT GA area of 6.82 ± 3.84 mm2. Despite the presence of apparent OCT segmentation errors, there was a significant correlation between FAF and uncorrected SDOCT measurements (r = 0.80; P < 0.001). Following manual correction of SDOCT GA segmentation errors, the measured GA area increased to 7.29 ± 4.18 mm2, and the correlation with the FAF-determined GA area significantly improved (r = 0.98; P < 0.001). CONCLUSIONS SDOCT-derived measurements of GA correlate well with areas of DDAF obtained from FAF images. Manual correction of SDOCT segmentation errors can further improve this correlation. These observations may support the use of SDOCT-based measurements of GA in clinical research and clinical trials.
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Affiliation(s)
- Swetha Bindu Velaga
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles
| | - Muneeswar G Nittala
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles
| | - Amirhossein Hariri
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles
| | - Srinivas R Sadda
- Doheny Image Reading Center, Doheny Eye Institute, Los Angeles, California; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles
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12
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Kiser PD. Retinal pigment epithelium 65 kDa protein (RPE65): An update. Prog Retin Eye Res 2021; 88:101013. [PMID: 34607013 PMCID: PMC8975950 DOI: 10.1016/j.preteyeres.2021.101013] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Revised: 09/21/2021] [Accepted: 09/24/2021] [Indexed: 12/21/2022]
Abstract
Vertebrate vision critically depends on an 11-cis-retinoid renewal system known as the visual cycle. At the heart of this metabolic pathway is an enzyme known as retinal pigment epithelium 65 kDa protein (RPE65), which catalyzes an unusual, possibly biochemically unique, reaction consisting of a coupled all-trans-retinyl ester hydrolysis and alkene geometric isomerization to produce 11-cis-retinol. Early work on this isomerohydrolase demonstrated its membership to the carotenoid cleavage dioxygenase superfamily and its essentiality for 11-cis-retinal production in the vertebrate retina. Three independent studies published in 2005 established RPE65 as the actual isomerohydrolase instead of a retinoid-binding protein as previously believed. Since the last devoted review of RPE65 enzymology appeared in this journal, major advances have been made in a number of areas including our understanding of the mechanistic details of RPE65 isomerohydrolase activity, its phylogenetic origins, the relationship of its membrane binding affinity to its catalytic activity, its role in visual chromophore production for rods and cones, its modulation by macromolecules and small molecules, and the involvement of RPE65 mutations in the development of retinal diseases. In this article, I will review these areas of progress with the goal of integrating results from the varied experimental approaches to provide a comprehensive picture of RPE65 biochemistry. Key outstanding questions that may prove to be fruitful future research pursuits will also be highlighted.
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Affiliation(s)
- Philip D Kiser
- Research Service, VA Long Beach Healthcare System, Long Beach, CA, 90822, USA; Department of Physiology & Biophysics, University of California, Irvine School of Medicine, Irvine, CA, 92697, USA; Department of Ophthalmology and Center for Translational Vision Research, Gavin Herbert Eye Institute, University of California, Irvine School of Medicine, Irvine, CA, 92697, USA.
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13
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Vitamin A cycle byproducts impede dark adaptation. J Biol Chem 2021; 297:101074. [PMID: 34391781 PMCID: PMC8427233 DOI: 10.1016/j.jbc.2021.101074] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 08/02/2021] [Accepted: 08/11/2021] [Indexed: 11/21/2022] Open
Abstract
Impaired dark adaptation (DA), a defect in the ability to adjust to dimly lit settings, is a universal hallmark of aging. However, the mechanisms responsible for impaired DA are poorly understood. Vitamin A byproducts, such as vitamin A dimers, are small molecules that form in the retina during the vitamin A cycle. We show that later in life, in the human eye, these byproducts reach levels commensurate with those of vitamin A. In mice, selectively inhibiting the formation of these byproducts, with the investigational drug C20D3-vitamin A, results in faster DA. In contrast, acutely increasing these ocular byproducts through exogenous delivery leads to slower DA, with otherwise preserved retinal function and morphology. Our findings reveal that vitamin A cycle byproducts alone are sufficient to cause delays in DA and suggest that they may contribute to universal age-related DA impairment. Our data further indicate that the age-related decline in DA may be tractable to pharmacological intervention by C20D3-vitamin A.
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14
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Scholl HPN, Boyer D, Giani A, Chong V. The use of neuroprotective agents in treating geographic atrophy. Ophthalmic Res 2021; 64:888-902. [PMID: 34153966 DOI: 10.1159/000517794] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 05/12/2021] [Indexed: 11/19/2022]
Affiliation(s)
- Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology, Basel, Switzerland
- Department of Ophthalmology, University of Basel, Basel, Switzerland
| | - David Boyer
- Retina-Vitreous Associates Medical Group, Los Angeles, California, USA
| | - Andrea Giani
- Boehringer Ingelheim International GmbH, Ingelheim am Rhein, Germany
| | - Victor Chong
- Boehringer Ingelheim International GmbH, Ingelheim am Rhein, Germany
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15
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Blum E, Zhang J, Zaluski J, Einstein DE, Korshin EE, Kubas A, Gruzman A, Tochtrop GP, Kiser PD, Palczewski K. Rational Alteration of Pharmacokinetics of Chiral Fluorinated and Deuterated Derivatives of Emixustat for Retinal Therapy. J Med Chem 2021; 64:8287-8302. [PMID: 34081480 DOI: 10.1021/acs.jmedchem.1c00279] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Recycling of all-trans-retinal to 11-cis-retinal through the visual cycle is a fundamental metabolic pathway in the eye. A potent retinoid isomerase (RPE65) inhibitor, (R)-emixustat, has been developed and tested in several clinical trials; however, it has not received regulatory approval for use in any specific retinopathy. Rapid clearance of this drug presents challenges to maintaining concentrations in eyes within a therapeutic window. To address this pharmacokinetic inadequacy, we rationally designed and synthesized a series of emixustat derivatives with strategically placed fluorine and deuterium atoms to slow down the key metabolic transformations known for emixustat. Crystal structures and quantum chemical analysis of RPE65 in complex with the most potent emixustat derivatives revealed the structural and electronic bases for how fluoro substituents can be favorably accommodated within the active site pocket of RPE65. We found a close (∼3.0 Å) F-π interaction that is predicted to contribute ∼2.4 kcal/mol to the overall binding energy.
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Affiliation(s)
- Eliav Blum
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Jianye Zhang
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, California 92697, United States
| | - Jordan Zaluski
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - David E Einstein
- Department of Physiology and Biophysics, University of California, Irvine, California 92697, United States.,Research Service, VA Long Beach Healthcare System, Long Beach, California 90822, United States
| | - Edward E Korshin
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Adam Kubas
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland
| | - Arie Gruzman
- Department of Chemistry, Faculty of Exact Sciences, Bar-Ilan University, Ramat-Gan 5290002, Israel
| | - Gregory P Tochtrop
- Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, United States
| | - Philip D Kiser
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, California 92697, United States.,Department of Physiology and Biophysics, University of California, Irvine, California 92697, United States.,Research Service, VA Long Beach Healthcare System, Long Beach, California 90822, United States
| | - Krzysztof Palczewski
- Department of Ophthalmology, Gavin Herbert Eye Institute, University of California, Irvine, California 92697, United States.,Department of Physiology and Biophysics, University of California, Irvine, California 92697, United States.,Department of Chemistry, University of California, Irvine, California 92697, United States
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16
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Thomas CN, Sim DA, Lee WH, Alfahad N, Dick AD, Denniston AK, Hill LJ. Emerging therapies and their delivery for treating age-related macular degeneration. Br J Pharmacol 2021; 179:1908-1937. [PMID: 33769566 DOI: 10.1111/bph.15459] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 03/11/2021] [Accepted: 03/14/2021] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) is the most common cause of blindness in the Western world and is characterised in its latter stages by retinal cell death and neovascularisation and earlier stages with the loss of parainflammatory homeostasis. Patients with neovascular AMD (nAMD) are treated with frequent intraocular injections of anti-vascular endothelial growth factor (VEGF) therapies, which are not only unpopular with patients but carry risks of sight-threatening complications. A minority of patients are unresponsive with no alternative treatment available, and some patients who respond initially eventually develop a tolerance to treatment. New therapeutics with improved delivery methods and sustainability of clinical effects are required, in particular for non-neovascular AMD (90% of cases and no current approved treatments). There are age-related and disease-related changes that occur which can affect ocular drug delivery. Here, we review the latest emerging therapies for AMD, their delivery routes and implications for translating to clinical practice.
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Affiliation(s)
- Chloe N Thomas
- School of Biomedical Sciences, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Dawn A Sim
- Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK.,National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital and University College London Institute of Ophthalmology, London, UK
| | - Wen Hwa Lee
- Action Against AMD, London, UK.,Affordable Medicines Programme, Oxford Martin School, University of Oxford, Oxford, UK
| | - Nada Alfahad
- School of Biomedical Sciences, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | - Andrew D Dick
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital and University College London Institute of Ophthalmology, London, UK.,Academic Unit of Ophthalmology, Bristol Medical School and School of Cellular and Molecular Medicine, University of Bristol, Bristol, UK
| | - Alastair K Denniston
- National Institute for Health Research (NIHR) Biomedical Research Centre at Moorfields Eye Hospital and University College London Institute of Ophthalmology, London, UK.,Academic Unit of Ophthalmology, Institute of Inflammation and Ageing, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK.,Department of Ophthalmology, University Hospitals Birmingham NHS Foundation Trust, Birmingham, UK.,Centre for Patient Reported Outcome Research, Institute of Applied Health Research, University of Birmingham, Birmingham, UK.,Birmingham Health Partners Centre for Regulatory Science and Innovation, University of Birmingham, Birmingham, UK.,Health Data Research UK, London, UK
| | - Lisa J Hill
- School of Biomedical Sciences, Institute of Clinical Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
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17
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Kiser PD, Palczewski K. Pathways and disease-causing alterations in visual chromophore production for vertebrate vision. J Biol Chem 2021; 296:100072. [PMID: 33187985 PMCID: PMC7948990 DOI: 10.1074/jbc.rev120.014405] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
All that we view of the world begins with an ultrafast cis to trans photoisomerization of the retinylidene chromophore associated with the visual pigments of rod and cone photoreceptors. The continual responsiveness of these photoreceptors is then sustained by regeneration processes that convert the trans-retinoid back to an 11-cis configuration. Recent biochemical and electrophysiological analyses of the retinal G-protein-coupled receptor (RGR) suggest that it could sustain the responsiveness of photoreceptor cells, particularly cones, even under bright light conditions. Thus, two mechanisms have evolved to accomplish the reisomerization: one involving the well-studied retinoid isomerase (RPE65) and a second photoisomerase reaction mediated by the RGR. Impairments to the pathways that transform all-trans-retinal back to 11-cis-retinal are associated with mild to severe forms of retinal dystrophy. Moreover, with age there also is a decline in the rate of chromophore regeneration. Both pharmacological and genetic approaches are being used to bypass visual cycle defects and consequently mitigate blinding diseases. Rapid progress in the use of genome editing also is paving the way for the treatment of disparate retinal diseases. In this review, we provide an update on visual cycle biochemistry and then discuss visual-cycle-related diseases and emerging therapeutics for these disorders. There is hope that these advances will be helpful in treating more complex diseases of the eye, including age-related macular degeneration (AMD).
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Affiliation(s)
- Philip D Kiser
- The Department of Physiology & Biophysics, University of California, Irvine, California, USA; Research Service, The VA Long Beach Health Care System, Long Beach, California, USA; The Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California, USA.
| | - Krzysztof Palczewski
- The Department of Physiology & Biophysics, University of California, Irvine, California, USA; The Gavin Herbert Eye Institute, Department of Ophthalmology, University of California, Irvine, California, USA; The Department of Chemistry, University of California, Irvine, California, USA.
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18
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Effects of emixustat hydrochloride in patients with proliferative diabetic retinopathy: a randomized, placebo-controlled phase 2 study. Graefes Arch Clin Exp Ophthalmol 2021; 259:369-378. [PMID: 32852613 PMCID: PMC7843479 DOI: 10.1007/s00417-020-04899-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 07/29/2020] [Accepted: 08/16/2020] [Indexed: 01/18/2023] Open
Abstract
PURPOSE To evaluate the effects of oral emixustat hydrochloride on pro-angiogenic and inflammatory cytokines in the aqueous humor, as well as other ophthalmic parameters, in subjects with proliferative diabetic retinopathy (PDR). METHODS Twenty-three patients with PDR, with or without diabetic macular edema (DME), were assigned to emixustat or placebo in daily oral doses ranging from 5 to 40 mg over a step-up titration period, for 84 days. The main outcome measures included levels of IL-1β, IL-6, IL-8, TGFβ-1, and VEGF in the aqueous humor. RESULTS Seven of 12 subjects (58%) who were randomized to emixustat and 11 of 12 subjects (92%) who were randomized to placebo completed the study. No statistically significant differences between treatment groups were observed for changes in any of the aqueous humor cytokines tested. However, median VEGF levels were slightly reduced in the emixustat but not the placebo group (- 70.0 pg/mL versus + 42.7 pg/mL, or - 11.8% versus + 6.7%). In a post hoc analysis of all subjects (with or without DME), statistically significant differences between treatment arms in mean changes from baseline in central subfield thickness (CST; emixustat - 11.9 μm, placebo + 36.2 μm; P = 0.076) and total macular volume (TMV; emixustat - 0.13 mm3, placebo + 0.23 mm3; P = 0.026) were observed, both favoring emixustat. Emixustat's safety profile was consistent with prior studies (i.e., the adverse events of delayed dark adaptation and visual impairment were more common in subjects treated with emixustat). CONCLUSION Although this pilot study did not demonstrate statistically significant differences in changes in aqueous humor cytokine levels between the emixustat and placebo groups, VEGF levels were slightly reduced in the emixustat but not in the placebo group. In addition, statistically significant differences favoring the emixustat group were observed in CST and TMV among all subjects. These data warrant further investigation of emixustat's potential therapeutic effects in diabetic retinopathy. TRIAL REGISTRATION ClinicalTrials.gov identifier: NCT02753400 (April 2016).
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19
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Yeong JL, Loveman E, Colquitt JL, Royle P, Waugh N, Lois N. Visual cycle modulators versus placebo or observation for the prevention and treatment of geographic atrophy due to age-related macular degeneration. Cochrane Database Syst Rev 2020; 12:CD013154. [PMID: 33331670 PMCID: PMC10726984 DOI: 10.1002/14651858.cd013154.pub2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Age-related macular degeneration (AMD) is a highly prevalent condition in an ever-increasing elderly population. Although insidious in the early stages, advanced AMD (neovascular and atrophic forms) can cause significant visual disability and economic burden on health systems worldwide. The most common form, geographic atrophy, has no effective treatment to date, whereas neovascular AMD can be treated with intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections. Geographic atrophy has a slow disease progression and patients tend to have preserved central vision until the final stages. This tendency, coupled with the use of modern imaging modalities, provides a large window of opportunity to intervene with validated methods to assess treatment efficacy. As geographic atrophy is an increasingly common condition with no effective intervention, many treatments are under investigation, one of which is visual cycle modulators. These medications have been shown to reduce lipofuscin accumulation in pre-clinical studies that have led to several clinical trials, reviewed herein. OBJECTIVES To assess the efficacy and safety of visual cycle modulators for the prevention and treatment of geographic atrophy secondary to AMD. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2020, Issue 1); MEDLINE Ovid; Embase Ovid; Web of Science Core Collection; Scopus; Association for Research in Vision and Ophthalmology (ARVO) website; ClinicalTrials.gov and the WHO ICTRP to 11 January 2020 with no language restrictions. We also searched using the reference lists of reviews and existing studies and the Cited Reference Search function in Web of Science to identify further relevant studies. SELECTION CRITERIA We included randomised controlled trials (RCTs) and quasi-randomised clinical studies (if available) that compared visual cycle modulators to placebo or no treatment (observation) in people diagnosed with AMD (early, intermediate or geographic atrophy). DATA COLLECTION AND ANALYSIS Two authors independently assessed risk of bias in the included studies and extracted data. Both authors entered data into RevMan 5. We resolved discrepancies through discussion. We graded the certainty of the evidence using the GRADE approach. MAIN RESULTS We included three RCTs from the USA; one of these had clinical sites in Germany. Two studies compared emixustat to placebo while the other compared fenretinide to placebo. All assigned one study eye per participant and, combined, have a total of 821 participants with a majority white ethnicity (97.6%). All participants were diagnosed with geographic atrophy due to AMD based on validated imaging modalities. All three studies have high risk of attrition bias mainly due to ocular adverse effects of emixustat and fenretinide. We considered only one study to be adequately conducted and reported with high risk of bias in only one domain (attrition bias). We considered the other two studies to be poorly reported and to have high risk of attrition bias and reporting bias. People with geographic atrophy treated with emixustat may not experience a clinically important change in best-corrected visual acuity (BCVA) between baseline and 24 months compared to people treated with placebo (mean difference (MD) 1.9 Early Treatment Diabetic Retinopathy Study (ETDRS) letters, 95% confidence interval (CI) -2.34 to 6.14, low-certainty evidence). Emixustat may also result in little or no difference in loss of 15 ETDRS letters or more of BCVA compared with placebo at 24 months (16.4% versus 18%) (risk ratio (RR) 0.91, 95% CI 0.59 to 1.4, low-certainty evidence). In terms of disease progression, emixustat may result in little or no difference in the annual growth rate of geographic atrophy compared with placebo (mean difference MD 0.09 mm2/year (95% CI -0.26 to 0.44, low-certainty evidence). All three studies reported adverse events of both drugs (emixustat: moderate-certainty evidence; fenretinide: low-certainty evidence). The main adverse events were ocular in nature and associated with the mechanism of action of the drugs. Delayed dark adaptation (emixustat: 54.5%; fenretinide: 39.3%) and chromatopsia (emixustat: 22.6%; fenretinide: 25.2%) were the most common adverse events reported, and were the most prevalent reasons for study dropout in emixustat trials. These effects were dose-dependent and resolved after drug cessation. No specific systemic adverse events were considered related to emixustat; only pruritus and rash were considered to be due to fenretinide. One emixustat study reported six deaths, none deemed related to the drug. None of the included RCTs reported the other pre-specified outcomes, including proportion of participants losing 10 letters or more, and mean change in macular sensitivity. We planned to investigate progression to advanced AMD (geographic atrophy or neovascular AMD) in prevention studies, including participants with early or intermediate AMD, but we identified no such studies. Two of the included studies reported an additional outcome - incidence of choroidal neovascularisation (CNV) - that was not in our published protocol. CNV onset may be reduced in those treated with emixustat but the evidence was uncertain (risk ratio (RR) 0.67, 95% CI 0.27 to 1.65, low-certainty evidence), or fenretinide (RR 0.5, 95% CI 0.26 to 0.98, low-certainty evidence) compared to placebo. A dose-dependent relationship was observed with emixustat. AUTHORS' CONCLUSIONS There is limited evidence to support the use of visual cycle modulators (emixustat and fenretinide) for the treatment of established geographic atrophy due to AMD. The possible reduction in the incidence of CNV observed with fenretinide, and to a lesser extent, emixustat, requires formal assessment in focused studies.
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Affiliation(s)
- Jian Lee Yeong
- Belfast and Social Care Trust, Royal Victoria Hospital, Belfast, UK
| | | | | | - Pamela Royle
- Warwick Evidence, Health Sciences Research Institute, Warwick Medical School, University of Warwick, Coventry, UK
| | - Norman Waugh
- Division of Health Sciences, Warwick Medical School, University of Warwick, Coventry, UK
| | - Noemi Lois
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's University, Belfast, UK
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20
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Kubota R, Birch DG, Gregory JK, Koester JM. Randomised study evaluating the pharmacodynamics of emixustat hydrochloride in subjects with macular atrophy secondary to Stargardt disease. Br J Ophthalmol 2020; 106:403-408. [PMID: 33214244 PMCID: PMC8867285 DOI: 10.1136/bjophthalmol-2020-317712] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 09/26/2020] [Accepted: 10/30/2020] [Indexed: 12/12/2022]
Abstract
Background/Aims Stargardt disease is a rare, inherited, degenerative disease of the retina that is the most common type of hereditary macular dystrophy. Currently, no approved treatments for the disease exist. The purpose of this study was to characterise the pharmacodynamics of emixustat, an orally available small molecule that targets the retinal pigment epithelium–specific 65 kDa protein (RPE65), in subjects with macular atrophy secondary to Stargardt disease. Methods In this multicentre study conducted at six study sites in the USA, 23 subjects with macular atrophy secondary to Stargardt disease were randomised to one of three doses of daily emixustat (2.5 mg, 5 mg or 10 mg) and treated for 1 month. The primary outcome was the suppression of the rod b-wave recovery rate on electroretinography after photobleaching, which is an indirect measure of RPE65 inhibition. Results Subjects who received 10 mg emixustat showed near-complete suppression of the rod b-wave amplitude recovery rate postphotobleaching (mean=91.86%, median=96.69%), whereas those who received 5 mg showed moderate suppression (mean=52.2%, median=68.0%). No effect was observed for subjects who received 2.5 mg emixustat (mean=−3.31%, median=−12.23%). The adverse event profile was consistent with prior studies in other patient populations and consisted primarily of ocular adverse events likely related to RPE65 inhibition. Conclusion This study demonstrated dose-dependent suppression of rod b-wave amplitude recovery postphotobleaching, confirming emixustat’s biological activity in patients with Stargardt disease. These findings informed dose selection for a 24-month phase 3 trial (SeaSTAR Study) that is now comparing emixustat to placebo in the treatment of Stargardt disease-associated macular atrophy.
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Affiliation(s)
- Ryo Kubota
- President, Kubota Vision Inc, Seattle, Washington, USA
| | - David G Birch
- Scientific Director, Retina Foundation of the Southwest, Dallas, Texas, USA
| | - Jeff K Gregory
- Clinical Development, Kubota Vision Inc, Seattle, Washington, USA
| | - John M Koester
- Clinical Development, Kubota Vision Inc, Seattle, Washington, USA
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21
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Nittala MG, Uji A, Velaga SB, Hariri AH, Naor J, Birch DG, Spencer R, Leng T, Capela A, Tsukamoto A, Ip M, Sadda SR. Effect of Human Central Nervous System Stem Cell Subretinal Transplantation on Progression of Geographic Atrophy Secondary to Nonneovascular Age-Related Macular Degeneration. Ophthalmol Retina 2020; 5:32-40. [PMID: 32562884 DOI: 10.1016/j.oret.2020.06.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 06/09/2020] [Indexed: 01/28/2023]
Abstract
PURPOSE To evaluate the effect of subretinally transplanted human central nervous system stem cells (HuCNS-SC) on the progression of geographic atrophy (GA) in patients with nonneovascular age-related macular degeneration (AMD). DESIGN Multicenter, prospective, phase 1 open-label clinical trial. PARTICIPANTS Fifteen patients with bilateral GA solely the result of AMD. METHODS The eye with the worst best-corrected visual acuity from each patient was selected for treatment and was considered the study eye; fellow eyes served as controls. A total of 0.25 × 106 or 1.0 × 106 HuCNS-SCs were infused directly into the subretinal space, superotemporal to the fovea near the junctional zone, outside the area of GA. All patients underwent spectral-domain OCT and fundus autofluorescence imaging using the Spectralis HRA+OCT (Heidelberg Engineering, Inc., Heidelberg, Germany). Total GA area in both eyes was measured at baseline and month 12 by certified reading center graders using the Spectralis Region Finder software. Sectoral (clock hour) per directional radial GA progression rates with respect to the foveal center in both eyes were calculated using the polar transformation method in Image J software (National Institutes of Health, Bethesda, MD). To facilitate comparative analysis across the cohort, all eyes were transformed to a right-eye orientation. MAIN OUTCOME MEASURES Total GA area and sectoral per directional GA progression rates were compared in both study and control eyes. RESULTS No statistically significant difference was found in mean change in total GA area at month 12 between study and fellow eyes (1.07 ± 0.84 mm2 vs. 2.08 ± 1.97 mm2; P = 0.08). However, the month 12 sectoral per directional radial GA growth rate for the superotemporal region (i.e., the location of HuCNS-SC transplantation) showed a significantly slower progression rate in study eyes than in fellow eyes (0.29 ± 0.58 mm vs. 1.08 ± 0.65 mm; P = 0.007). The progression rate in the superotemporal quadrant of the study eye was significantly slower than in the other 3 quadrants combined (P = 0.04). CONCLUSIONS In this small pilot study, HuCNS-SC transplantation seems to be associated with slower expansion of the GA lesion in the transplanted quadrant. Larger confirmatory studies are required. Sectoral or directional analysis of growth rates of GA may be a useful approach for assessing the efficacy of locally delivered therapies.
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Affiliation(s)
| | - Akihito Uji
- Doheny Eye Institute, Los Angeles, California
| | | | | | - Joel Naor
- Kodiak Sciences, Palo Alto, California
| | | | | | - Theodore Leng
- Byers Eye Institute at Stanford, Stanford University School of Medicine, Palo Alto, California
| | | | | | - Michel Ip
- Doheny Eye Institute, Los Angeles, California; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Srinivas R Sadda
- Doheny Eye Institute, Los Angeles, California; Department of Ophthalmology, David Geffen School of Medicine at UCLA, Los Angeles, California.
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Sun D, Schur RM, Sears AE, Gao SQ, Sun W, Naderi A, Kern T, Palczewski K, Lu ZR. Stable Retinoid Analogue Targeted Dual pH-Sensitive Smart Lipid ECO/pDNA Nanoparticles for Specific Gene Delivery in the Retinal Pigment Epithelium. ACS APPLIED BIO MATERIALS 2020; 3:3078-3086. [PMID: 34327311 DOI: 10.1021/acsabm.0c00130] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Da Sun
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Rebecca M Schur
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Avery E Sears
- Department of Pharmacology, Case Western Reserve University, Cleveland, OH 44106
| | - Song-Qi Gao
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Wenyu Sun
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Amirreza Naderi
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
| | - Timothy Kern
- Department of Ophthalmology, University of California Irvine, Irvine, CA 92697-7600
| | - Krzysztof Palczewski
- Department of Ophthalmology, University of California Irvine, Irvine, CA 92697-7600
| | - Zheng-Rong Lu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106
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Cremers FPM, Lee W, Collin RWJ, Allikmets R. Clinical spectrum, genetic complexity and therapeutic approaches for retinal disease caused by ABCA4 mutations. Prog Retin Eye Res 2020; 79:100861. [PMID: 32278709 PMCID: PMC7544654 DOI: 10.1016/j.preteyeres.2020.100861] [Citation(s) in RCA: 166] [Impact Index Per Article: 41.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 12/18/2022]
Abstract
The ABCA4 protein (then called a “rim protein”) was first
identified in 1978 in the rims and incisures of rod photoreceptors. The
corresponding gene, ABCA4, was cloned in 1997, and variants
were identified as the cause of autosomal recessive Stargardt disease (STGD1).
Over the next two decades, variation in ABCA4 has been
attributed to phenotypes other than the classically defined STGD1 or fundus
flavimaculatus, ranging from early onset and fast progressing cone-rod dystrophy
and retinitis pigmentosa-like phenotypes to very late onset cases of mostly mild
disease sometimes resembling, and confused with, age-related macular
degeneration. Similarly, analysis of the ABCA4 locus uncovered
a trove of genetic information, including >1200 disease-causing mutations
of varying severity, and of all types – missense, nonsense, small
deletions/insertions, and splicing affecting variants, of which many are located
deep-intronic. Altogether, this has greatly expanded our understanding of
complexity not only of the diseases caused by ABCA4 mutations,
but of all Mendelian diseases in general. This review provides an in depth
assessment of the cumulative knowledge of ABCA4-associated retinopathy –
clinical manifestations, genetic complexity, pathophysiology as well as current
and proposed therapeutic approaches.
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Affiliation(s)
- Frans P M Cremers
- Department of Human Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, PO Box 9104, 6500 HE, Nijmegen, the Netherlands.
| | - Winston Lee
- Department of Ophthalmology, Columbia University, New York, NY, 10032, USA; Department of Genetics & Development, Columbia University, New York, NY, 10032, USA
| | - Rob W J Collin
- Department of Human Genetics, Radboud University Medical Center, PO Box 9101, 6500 HB, Nijmegen, the Netherlands; Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, PO Box 9104, 6500 HE, Nijmegen, the Netherlands
| | - Rando Allikmets
- Department of Ophthalmology, Columbia University, New York, NY, 10032, USA; Department of Pathology & Cell Biology, Columbia University, New York, NY, 10032, USA.
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Kubota R, Calkins DJ, Henry SH, Linsenmeier RA. Emixustat Reduces Metabolic Demand of Dark Activity in the Retina. Invest Ophthalmol Vis Sci 2020; 60:4924-4930. [PMID: 31770432 DOI: 10.1167/iovs.19-28194] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose In the dark, photoreceptor outer segments contain high levels of cyclic guanosine 3'-5' monophosphate (cGMP), which binds to ion channels, holding them open and allowing an influx of cations. Ion pumping activity, which balances cation influx, uses considerable amounts of adenosine triphosphate (ATP) and oxygen. Light reduces cation influx and thereby lowers metabolic demand. Blood vessels are compromised in the diabetic retina and may not be able to meet the higher metabolic demand in darkness. Emixustat is a visual cycle modulator (VCM) that reduces chromophore levels and, therefore, may mimic light conditions. We evaluated the effect of emixustat on oxygen consumption and cation influx in dark conditions. Methods Cation influx was measured in rats using Mn2+-magnetic resonance imaging (MEMRI). Retinal oxygen profiles were recorded to evaluate oxygen consumption. In the MEMRI protocol, animals were treated with either emixustat or vehicle. In the oxygen protocol, animals were untreated or treated with emixustat. Results In vehicle-treated animals, cation channel activity increased in the dark. Emixustat treatment reduced cation channel activity; activity was comparable to vehicle-treated controls in light conditions. In vehicle-treated animals, minimum retinal oxygen tension decreased as the retina recovered from a photobleach, indicating that more oxygen was being consumed. Emixustat treatment prevented the decrease in oxygen pressure after photobleach. Conclusions Emixustat reduced the cation influx and retinal oxygen consumption associated with dark conditions. VCMs are a promising potential treatment for ischemic retinal neovascularization, such as that in diabetic retinopathy.
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Affiliation(s)
- Ryo Kubota
- Acucela, Inc., Seattle, Washington, United States
| | - David J Calkins
- Department of Ophthalmology and Visual Sciences, Vanderbilt University Medical Center, Nashville, Tennessee, United States
| | | | - Robert A Linsenmeier
- Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, United States.,Department of Neurobiology, Northwestern University, Evanston, Illinois, United States
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25
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Pharmacotherapy for metabolic and cellular stress in degenerative retinal diseases. Drug Discov Today 2019; 25:292-304. [PMID: 31809750 DOI: 10.1016/j.drudis.2019.11.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 11/08/2019] [Accepted: 11/26/2019] [Indexed: 12/13/2022]
Abstract
Retinal photoreceptors continually endure stresses associated with prolonged light exposure and the metabolic demands of dark adaptation. Although healthy photoreceptors are able to withstand these stresses for several decades, the disease-affected retina functions at a reduced capacity and is at an increased risk for dysfunction. To alleviate cellular and metabolic stressors in degenerative retinal diseases, a new class of drugs that modulate the metabolic activity of the retina have been developed. A clinical candidate in this class (emixustat) has been shown to reduce retinal pathology in various animal models of human retinal disease and is currently under clinical study. Here, we describe the pharmacological properties of emixustat, its mechanisms of action, and potential for use in the treatment of specific retinal diseases.
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Waugh N, Loveman E, Colquitt J, Royle P, Yeong JL, Hoad G, Lois N. Treatments for dry age-related macular degeneration and Stargardt disease: a systematic review. Health Technol Assess 2019; 22:1-168. [PMID: 29846169 DOI: 10.3310/hta22270] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
BACKGROUND Age-related macular degeneration (AMD) is the leading cause of visual loss in older people. Advanced AMD takes two forms, neovascular (wet) and atrophic (dry). Stargardt disease (STGD) is the commonest form of inherited macular dystrophy. OBJECTIVE To carry out a systematic review of treatments for dry AMD and STGD, and to identify emerging treatments where future NIHR research might be commissioned. DESIGN Systematic review. METHODS We searched MEDLINE, EMBASE, Web of Science and The Cochrane Library from 2005 to 13 July 2017 for reviews, journal articles and meeting abstracts. We looked for studies of interventions that aim to preserve or restore vision in people with dry AMD or STGD. The most important outcomes are those that matter to patients: visual acuity (VA), contrast sensitivity, reading speed, ability to drive, adverse effects of treatment, quality of life, progression of disease and patient preference. However, visual loss is a late event and intermediate predictors of future decline were accepted if there was good evidence that they are strong predictors of subsequent visual outcomes. These include changes detectable by investigation, but not necessarily noticed by people with AMD or STGD. ClinicalTrials.gov, the World Health Organization search portal and the UK Clinical Trials gateway were searched for ongoing and recently completed clinical trials. RESULTS The titles and abstracts of 7948 articles were screened for inclusion. The full text of 398 articles were obtained for further screening and checking of references and 112 articles were included in the final report. Overall, there were disappointingly few good-quality studies (including of sufficient size and duration) reporting useful outcomes, particularly in STGD. However we did identify a number of promising research topics, including drug treatments, stem cells, new forms of laser treatment, and implantable intraocular lens telescopes. In many cases, research is already under way, funded by industry or governments. LIMITATIONS In AMD, the main limitation came from the poor quality of much of the evidence. Many studies used VA as their main outcome despite not having sufficient duration to observe changes. The evidence on treatments for STGD is sparse. Most studies tested interventions with no comparison group, were far too short term, and the quality of some studies was poor. FUTURE WORK We think that the topics on which the Health Technology Assessment (HTA) and Efficacy Mechanism and Evaluation (EME) programmes might consider commissioning primary research are in STGD, a HTA trial of fenretinide (ReVision Therapeutics, San Diego, CA, USA), a visual cycle inhibitor, and EME research into the value of lutein and zeaxanthin supplements, using short-term measures of retinal function. In AMD, we suggest trials of fenretinide and of a potent statin. There is epidemiological evidence from the USA that the drug, levodopa, used for treating Parkinson's disease, may reduce the incidence of AMD. We suggest that similar research should be carried out using the large general practice databases in the UK. Ideally, future research should be at earlier stages in both diseases, before vision is impaired, using sensitive measures of macular function. This may require early detection of AMD by screening. STUDY REGISTRATION This study is registered as PROSPERO CRD42016038708. FUNDING The National Institute for Health Research HTA programme.
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Affiliation(s)
- Norman Waugh
- Division of Health Sciences, University of Warwick, Coventry, UK
| | | | | | - Pamela Royle
- Division of Health Sciences, University of Warwick, Coventry, UK
| | | | | | - Noemi Lois
- Ophthalmology, Royal Victoria Hospital, Belfast, UK.,Wellcome-Wolfson Centre for Experimental Medicine, Queens University, Belfast, UK
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Reid MJ, Eyre R, Podoll T. Oxidative Deamination of Emixustat by Human Vascular Adhesion Protein-1/Semicarbazide-Sensitive Amine Oxidase. Drug Metab Dispos 2019; 47:504-515. [PMID: 30787099 DOI: 10.1124/dmd.118.085811] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 01/28/2019] [Indexed: 12/25/2022] Open
Abstract
Emixustat potently inhibits the visual cycle isomerase retinal pigment epithelium protein 65 (RPE65) to reduce the accumulation of toxic bisretinoid by-products that lead to various retinopathies. Orally administered emixustat is cleared rapidly from the plasma, with little excreted unchanged. The hydroxypropylamine moiety that is critical in emixustat's inhibition of RPE65 is oxidatively deaminated to three major carboxylic acid metabolites that appear rapidly in plasma. These metabolites greatly exceed the plasma concentrations of emixustat and demonstrate formation-rate-limited metabolite kinetics. This study investigated in vitro deamination of emixustat in human vascular membrane fractions, plasma, and recombinant human vascular adhesion protein-1 (VAP-1), demonstrating single-enzyme kinetics for the formation of a stable aldehyde intermediate (ACU-5201) in all in vitro systems. The in vitro systems used herein established sequential formation of the major metabolites with addition of assay components for aldehyde dehydrogenase and cytochrome P450. Reaction phenotyping experiments using selective chemical inhibitors and recombinant enzymes of monoamine oxidase, VAP-1, and lysyl oxidase showed that only VAP-1 deaminated emixustat. In individually derived human vascular membranes from umbilical cord and aorta, rates of emixustat deamination were highly correlated to VAP-1 marker substrate activity (benzylamine) and VAP-1 levels measured by enzyme-linked immunosorbent assay. In donor-matched plasma samples, soluble VAP-1 activity and levels were lower than in aorta membranes. A variety of potential comedications did not strongly inhibit emixustat deamination in vitro.
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Affiliation(s)
- Michael J Reid
- Acucela Inc., Seattle, Washington (M.J.R.); MavuPharma, Kirkland, Washington (R.E.); and IV-PO, LLC, Seattle, Washington (T.P.)
| | - Russell Eyre
- Acucela Inc., Seattle, Washington (M.J.R.); MavuPharma, Kirkland, Washington (R.E.); and IV-PO, LLC, Seattle, Washington (T.P.)
| | - Terry Podoll
- Acucela Inc., Seattle, Washington (M.J.R.); MavuPharma, Kirkland, Washington (R.E.); and IV-PO, LLC, Seattle, Washington (T.P.)
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29
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Validation and reproducibility of an LC-MS/MS method for emixustat and its three deaminated metabolites in human plasma. Bioanalysis 2018; 10:1803-1817. [PMID: 30325202 DOI: 10.4155/bio-2018-0159] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Aim: A sensitive method to quantify emixustat and its rapidly formed three major deaminated metabolites in human plasma was necessary to determine exposure in clinical trials. Methods: An LC-MS/MS method was validated for accuracy and precision, linearity, carry over, selectivity, recovery, matrix effects, hematocrit effects and stability. Results: A quantitative procedure for the determination of emixustat, ACU-5116, ACU-5124 and ACU-5149 in human plasma over the concentration range of 0.0500/1.00/1.00/1.00-10.0/1000/1000/1000 ng/ml, was successfully validated and has been used to successfully analyze samples in three clinical trials. Incurred sample reanalysis was performed for all four analytes in each study with >92% of the repeat results and original results within 20% of the mean of the two values.
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RELIABILITY OF CONFOCAL WHITE-LIGHT FUNDUS IMAGING FOR MEASUREMENT OF RETINA PIGMENT EPITHELIAL ATROPHY IN AGE-RELATED MACULAR DEGENERATION. Retina 2018; 38:1930-1936. [DOI: 10.1097/iae.0000000000001949] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Robinson DG, Margrain TH, Dunn MJ, Bailey C, Binns AM. Low-Level Nighttime Light Therapy for Age-Related Macular Degeneration: A Randomized Clinical Trial. ACTA ACUST UNITED AC 2018; 59:4531-4541. [DOI: 10.1167/iovs.18-24284] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- D. Grant Robinson
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Tom H. Margrain
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Matt J. Dunn
- School of Optometry and Vision Sciences, Cardiff University, Cardiff, United Kingdom
| | - Clare Bailey
- Bristol Eye Hospital, Lower Maudlin Street, Bristol, United Kingdom
| | - Alison M. Binns
- Division of Optometry and Visual Science, School of Health Sciences, City, University of London, United Kingdom
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Hussain RM, Ciulla TA, Berrocal AM, Gregori NZ, Flynn HW, Lam BL. Stargardt macular dystrophy and evolving therapies. Expert Opin Biol Ther 2018; 18:1049-1059. [PMID: 30129371 DOI: 10.1080/14712598.2018.1513486] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
INTRODUCTION Stargardt macular dystrophy (STGD1) is a hereditary retinal degeneration that lacks effective treatment options. Gene therapy, stem cell therapy, and pharmacotherapy with visual cycle modulators (VCMs) and complement inhibitors are discussed as potential treatments. AREAS COVERED Investigational therapies for STGD1 aim to reduce toxic bisretinoids and lipofuscin in the retina and retinal pigment epithelium (RPE). These agents include C20-D3-vitamin A (ALK-001), isotretinoin, VM200, emixustat, and A1120. Avacincaptad pegol is a C5 complement inhibitor that may reduce inflammation-related RPE damage. Animal models of STGD1 show promising data for these treatments, though proof of efficacy in humans is lacking. Fenretinide and emixustat are VCMs for dry AMD and STGD1 that failed to halt geographic atrophy progression or improve vision in trials for AMD. A1120 prevents retinol transport into RPE and may spare side effects typically seen with VCMs (nyctalopia and chromatopsia). Stem cell transplantation suggests potential biologic plausibility in a phase I/II trial. Gene therapy aims to augment the mutated ABCA4 gene, though results of a phase I/II trial are pending. EXPERT OPINION Stem cell transplantation, ABCA4 gene therapy, VCMs, and complement inhibitors offer biologically plausible treatment mechanisms for treatment of STGD1. Further trials are warranted to assess efficacy and safety in humans.
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Affiliation(s)
- Rehan M Hussain
- a Department of Ophthalmology, Bascom Palmer Eye Institute , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Thomas A Ciulla
- b Retina Service , Midwest Eye Institute and Department of Ophthalmology, Indiana University School of Medicine , Indianapolis , IN , USA
| | - Audina M Berrocal
- a Department of Ophthalmology, Bascom Palmer Eye Institute , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Ninel Z Gregori
- a Department of Ophthalmology, Bascom Palmer Eye Institute , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Harry W Flynn
- a Department of Ophthalmology, Bascom Palmer Eye Institute , University of Miami Miller School of Medicine , Miami , FL , USA
| | - Byron L Lam
- a Department of Ophthalmology, Bascom Palmer Eye Institute , University of Miami Miller School of Medicine , Miami , FL , USA
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Wei Y, Liao H, Ye J. Therapeutic effects of various therapeutic strategies on non-exudative age-related macular degeneration: A PRISMA-compliant network meta-analysis of randomized controlled trials. Medicine (Baltimore) 2018; 97:e10422. [PMID: 29794727 PMCID: PMC6393096 DOI: 10.1097/md.0000000000010422] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE Age-related macular degeneration (AMD) is a chronic progressive central retinal disease. Geographic atrophy (GA) is a late stage of dry AMD (DAMD) and is a slowly but inexorably progressive disease that causes irreversible blindness over time. We aimed to assess various therapeutic strategies for DAMD and GA treatment by network meta-analysis. METHODS We searched PubMed, Embase, and the Cochrane Library to identify randomized controlled trials (RCTs) of atrophic AMD treatments published prior to December 16, 2017. Best-corrected visual acuity (BCVA) and change in GA area were evaluated to reflect therapeutic effects. A random-effects network meta-analysis, with a frequentist framework, was used to assess the effectiveness of therapeutic strategies for DAMD treatment. RESULTS We included 22 articles that assessed 16 types of regimens and 2482 patients in our meta-analysis. The network meta-analysis results showed that zinc-monocysteine (98.1%) was the most likely to improve BCVA (logMAR), followed by alprostadil (84.0%), eculizumab (70.5%), and rheohemapheresis (67.3%). In BCVA (letters) outcomes, rheohemapheresis (99.6%), lampalizumab (69.5%), and the antioxidant complex (67.9%) showed marked benefits in visual function recovery. Regarding the outcome of GA area change, isopropyl unoprostone (IU) (88.6%) might have the best GA area reduction; however, there was no significant difference between IU and the blank control. CONCLUSIONS Zinc-monocysteine and rheohemapheresis showed significantly better effects on BCVA (logMAR) improvement, and compared with the blank control, rheohemapheresis and the antioxidant complex showed better effects on BCVA (letters) improvement. Other treatments have potential effects on DAMD, including alprostadil, eculizumab, and lampalizumab. However, there is no effective treatment for GA area reduction.
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Rosenfeld PJ, Dugel PU, Holz FG, Heier JS, Pearlman JA, Novack RL, Csaky KG, Koester JM, Gregory JK, Kubota R. Emixustat Hydrochloride for Geographic Atrophy Secondary to Age-Related Macular Degeneration: A Randomized Clinical Trial. Ophthalmology 2018; 125:1556-1567. [PMID: 29716784 DOI: 10.1016/j.ophtha.2018.03.059] [Citation(s) in RCA: 88] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 03/26/2018] [Accepted: 03/28/2018] [Indexed: 02/07/2023] Open
Abstract
PURPOSE To determine whether emixustat hydrochloride (emixustat) reduces the rate of enlargement of geographic atrophy (GA) compared with placebo in subjects with age-related macular degeneration (AMD) and to evaluate the safety and tolerability of emixustat over 24 months of treatment. DESIGN Multicenter, randomized, double-masked, placebo-controlled, phase 2b/3 clinical trial. PARTICIPANTS Patients with GA secondary to AMD, a visual acuity score of at least 35 letters, and GA with a total area of 1.25 to 18 mm2 were enrolled. METHODS Subjects were randomized (1:1:1:1) to emixustat 2.5 mg, 5 mg, 10 mg, or placebo, administered orally once daily for 24 months. Visits included screening, baseline, and months 1, 2, 3, 6, 9, 12, 15, 18, 21, 24, and 25. MAIN OUTCOME MEASURES The primary efficacy end point was the mean annual growth rate of total GA area in the study eye, as measured by a central reading center using fundus autofluorescence (FAF) images. The change from baseline in normal luminance best-corrected visual acuity (NL-BCVA) was a secondary efficacy end point. RESULTS Of 508 randomized subjects, 320 completed the study. Demographics and baseline characteristics were comparable between treatment groups. On average, GA lesions in the study eye grew at a similar rate in each group (emixustat: 1.69 to 1.84 mm2/year; placebo: 1.69 mm2/year; P ≥ 0.81). Changes in NL-BCVA were also comparable between groups. Subjects with a larger low luminance deficit (LLD) at baseline (≥20 letters) demonstrated a more rapid growth of GA over 24 months. No relationship was observed between the risk-allele status of the AMD-associated single-nucleotide polymorphisms tested and the growth rate of GA. The most common adverse events in emixustat-treated subjects were delayed dark adaptation (55%), chromatopsia (18%), visual impairment (15%), and erythropsia (15%). CONCLUSIONS Emixustat did not reduce the growth rate of GA in AMD. The most common adverse events were ocular in nature and likely related to the drug's mechanism of action. Data gained from this study over a 2-year period add to the understanding of the natural history of GA and the baseline characteristics affecting the growth rate of GA.
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Affiliation(s)
- Philip J Rosenfeld
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, Florida.
| | | | - Frank G Holz
- Department of Ophthalmology, University of Bonn, Bonn, Germany
| | | | | | - Roger L Novack
- Retina-Vitreous Associates Medical Group, Los Angeles, California
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Hussain RM, Gregori NZ, Ciulla TA, Lam BL. Pharmacotherapy of retinal disease with visual cycle modulators. Expert Opin Pharmacother 2018. [DOI: 10.1080/14656566.2018.1448060] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Rehan M. Hussain
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Ninel Z. Gregori
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
| | - Thomas A. Ciulla
- Department of Ophthalmology, Retina Service, Midwest Eye Institute, Indianapolis, IN, USA
- Retina Service, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Byron L. Lam
- Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA
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Schur RM, Gao S, Yu G, Chen Y, Maeda A, Palczewski K, Lu ZR. New GABA modulators protect photoreceptor cells from light-induced degeneration in mouse models. FASEB J 2018; 32:3289-3300. [PMID: 29401616 DOI: 10.1096/fj.201701250r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
No clinically approved therapies are currently available that prevent the onset of photoreceptor death in retinal degeneration. Signaling between retinal neurons is regulated by the release and uptake of neurotransmitters, wherein GABA is the main inhibitory neurotransmitter. In this work, novel 3-chloropropiophenone derivatives and the clinical anticonvulsants tiagabine and vigabatrin were tested to modulate GABA signaling and protect against light-induced retinal degeneration. Abca4-/-Rdh8-/- mice, an accelerated model of retinal degeneration, were exposed to intense light after prophylactic injections of one of these compounds. Imaging and functional assessments of the retina indicated that these compounds successfully protected photoreceptor cells from degeneration to maintain a full-visual-field response. Furthermore, these compounds demonstrated a strong safety profile in wild-type mice and did not compromise visual function or damage the retina, despite repeated administration. These results indicate that modulating inhibitory GABA signaling can offer prophylactic protection against light-induced retinal degeneration.-Schur, R. M., Gao, S., Yu, G., Chen, Y., Maeda, A., Palczewski, K., Lu, Z.-R. New GABA modulators protect photoreceptor cells from light-induced degeneration in mouse models.
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Affiliation(s)
- Rebecca M Schur
- Case Center for Biomolecular Engineering, Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Songqi Gao
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Guanping Yu
- Case Center for Biomolecular Engineering, Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, Ohio, USA
| | - Yu Chen
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Akiko Maeda
- Department of Ophthalmology and Visual Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Krzysztof Palczewski
- Department of Pharmacology, Cleveland Center for Membrane and Structural Biology, School of Medicine, Case Western Reserve University, Cleveland, Ohio, USA
| | - Zheng-Rong Lu
- Case Center for Biomolecular Engineering, Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, Ohio, USA
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Kandasamy R, Wickremasinghe S, Guymer R. New Treatment Modalities for Geographic Atrophy. Asia Pac J Ophthalmol (Phila) 2017; 6:508-513. [PMID: 28905539 DOI: 10.22608/apo.2017262] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Age‑related macular degeneration (AMD) is a significant cause of global visual morbidity and is projected to affect 288 million people by the year 2040. The advent of treatment with anti‒vascular endothelial growth factor (anti‑VEGF) drugs has revolutionized the treatment of neovascular AMD (nAMD) but there have been no similar breakthroughs for the treatment of geographic atrophy (GA) to retard its progression. The advancements in imaging and new understanding of disease mechanisms, based on molecular and genetic models, have paved the way for the development of novel experimental treatment options for GA that aim to cater to a thus far largely unmet need. This review paper focuses on the recent clinical trials of new treatment options for slowing GA progression rates with emphasis on the agents that are currently undergoing, or have already undergone, significant clinical trial testing. Several new groups of drugs, including those targeting the complement cascade and agents considered as neuroprotective, have shown some promising results and could potentially pave the way forward in the treatment of this devastating disease.
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Affiliation(s)
- Rathika Kandasamy
- Centre for Eye Research Australia, Department of Surgery (Ophthalmology), University of Melbourne, Royal Victorian Eye and Ear, Hospital, Melbourne, Australia
| | - Sanjeewa Wickremasinghe
- Centre for Eye Research Australia, Department of Surgery (Ophthalmology), University of Melbourne, Royal Victorian Eye and Ear, Hospital, Melbourne, Australia
| | - Robyn Guymer
- Centre for Eye Research Australia, Department of Surgery (Ophthalmology), University of Melbourne, Royal Victorian Eye and Ear, Hospital, Melbourne, Australia
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RPE65 has an additional function as the lutein to meso-zeaxanthin isomerase in the vertebrate eye. Proc Natl Acad Sci U S A 2017; 114:10882-10887. [PMID: 28874556 DOI: 10.1073/pnas.1706332114] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Carotenoids are plant-derived pigment molecules that vertebrates cannot synthesize de novo that protect the fovea of the primate retina from oxidative stress and light damage. meso-Zeaxanthin is an ocular-specific carotenoid for which there are no common dietary sources. It is one of the three major carotenoids present at the foveal center, but the mechanism by which it is produced in the eye is unknown. An isomerase enzyme is thought to be responsible for the transformation of lutein to meso-zeaxanthin by a double-bond shift mechanism, but its identity has been elusive. We previously found that meso-zeaxanthin is produced in a developmentally regulated manner in chicken embryonic retinal pigment epithelium (RPE)/choroid in the absence of light. In the present study, we show that RPE65, the isomerohydrolase enzyme of the vertebrate visual cycle that catalyzes the isomerization of all-trans-retinyl esters to 11-cis-retinol, is also the isomerase enzyme responsible for the production of meso-zeaxanthin in vertebrates. Its RNA is up-regulated 23-fold at the time of meso-zeaxanthin production during chicken eye development, and we present evidence that overexpression of either chicken or human RPE65 in cell culture leads to the production of meso-zeaxanthin from lutein. Pharmacologic inhibition of RPE65 function resulted in significant inhibition of meso-zeaxanthin biosynthesis during chicken eye development. Structural docking experiments revealed that the epsilon ring of lutein fits into the active site of RPE65 close to the nonheme iron center. This report describes a previously unrecognized additional activity of RPE65 in ocular carotenoid metabolism.
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Fitzsimmons ME, Sun G, Kuksa V, Reid MJ. Disposition, profiling and identification of emixustat and its metabolites in humans. Xenobiotica 2017; 48:592-604. [PMID: 28678597 DOI: 10.1080/00498254.2017.1350889] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
1. Emixustat is a small molecule that potently inhibits retinal pigment epithelium 65 isomerohydrolase. Emixustat is in clinical development for the treatment of various retinopathies (i.e. Stargardt disease and diabetic retinopathy). 2. A human absorption, distribution, metabolism, and excretion (ADME) study was conducted with a single dose of [14C]-emixustat in healthy male subjects. Total 14C content in plasma, urine, and faeces was determined using accelerator mass spectrometry (AMS), and metabolic profiles in pooled plasma and urine were investigated by both HPLC-AMS and 2D LC-MS/MS. 3. After a single, oral 40-mg dose of [14C]-emixustat, recovery of total 14C was nearly complete within 24 h. Urine was the major route of 14C elimination; accounting for > 90% of the administered dose. 4. Biotransformation of emixustat occurred primarily at two structural moieties; oxidation of the cyclohexyl moiety and oxidative deamination of the 3R-hydroxypropylamine, both independently and in combination to produce secondary metabolites. Metabolite profiling in pooled plasma samples identified 3 major metabolites: ACU-5124, ACU-5116 and ACU-5149, accounting for 29.0%, 11.5%, and 10.6% of total 14C, respectively. Emixustat was metabolized in human hepatocytes with unchanged emixustat accounting for 33.7% of sample radioactivity and predominantly cyclohexanol metabolites observed.
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Affiliation(s)
| | - Gang Sun
- a Covance Laboratories Inc , Madison , WI , USA and
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Taskintuna I, Elsayed MEAA, Schatz P. Update on Clinical Trials in Dry Age-related Macular Degeneration. Middle East Afr J Ophthalmol 2016; 23:13-26. [PMID: 26957835 PMCID: PMC4759891 DOI: 10.4103/0974-9233.173134] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
This review article summarizes the most recent clinical trials for dry age-related macular degeneration (AMD), the most common cause of vision loss in the elderly in developed countries. A literature search through websites https://www.pubmed.org and https://www.clinicaltrials.gov/, both accessed no later than November 04, 2015, was performed. We identified three Phase III clinical trials that were completed over the recent 5 years Age-Related Eye Disease Study 2 (AREDS2), implantable miniature telescope and tandospirone, and several other trials targeting a variety of mechanisms including, oxidative stress, complement inhibition, visual cycle inhibition, retinal and choroidal blood flow, stem cells, gene therapy, and visual rehabilitation. To date, none of the biologically oriented therapies have resulted in improved vision. Vision improvement was reported with an implantable mini telescope. Stem cells therapy holds a potential for vision improvement. The AREDS2 formulas did not add any further reduced risk of progression to advanced AMD, compared to the original AREDS formula. Several recently discovered pathogenetic mechanisms in dry AMD have enabled development of new treatment strategies, and several of these have been tested in recent clinical trials and are currently being tested in ongoing trials. The rapid development and understanding of pathogenesis holds promise for the future.
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Affiliation(s)
- Ibrahim Taskintuna
- Division of Vitreoretinal, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia
| | | | - Patrik Schatz
- Division of Vitreoretinal, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia; Department of Ophthalmology, Clinical Sciences, Scane County University Hospital, University of Lund, Sweden
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Khan KN, Mahroo OA, Khan RS, Mohamed MD, McKibbin M, Bird A, Michaelides M, Tufail A, Moore AT. Differentiating drusen: Drusen and drusen-like appearances associated with ageing, age-related macular degeneration, inherited eye disease and other pathological processes. Prog Retin Eye Res 2016; 53:70-106. [DOI: 10.1016/j.preteyeres.2016.04.008] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 04/24/2016] [Accepted: 04/27/2016] [Indexed: 12/11/2022]
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Abstract
Although currently available treatment options for age-related macular degeneration (AMD) are limited, particularly for atrophic AMD, the identification of predisposing genetic variations has informed clinical studies addressing therapeutic options such as complement inhibitors and anti-inflammatory agents. To lower risk of early AMD, recommended lifestyle interventions such as the avoidance of smoking and the intake of low glycemic antioxidant-rich diets have largely followed from the identification of nongenetic modifiable factors. On the other hand, the challenge of understanding the complex relationship between aging and cumulative damage leading to AMD has fueled investigations of the visual cycle adducts that accumulate in retinal pigment epithelial (RPE) cells and are a hallmark of aging retina. These studies have revealed properties of these compounds that provide insights into processes that may compromise RPE and could contribute to disease mechanisms in AMD. This work has also led to the design of targeted therapeutics that are currently under investigation.
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Affiliation(s)
- Janet R Sparrow
- Department of Ophthalmology, Columbia University Medical Center, New York, NY 10032; Department of Pathology and Cell Biology, Columbia University Medical Center, New York, NY 10032
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Abstract
Age-related macular degeneration (AMD), the most common form of irreversible blindness in the industrially developed world, can present years before a patient begins to lose vision. For most of these patients, AMD never progresses past its early stages to the advanced forms that are principally responsible for the vast majority of vision loss. Advanced AMD can manifest as either an advanced avascular form known as geographic atrophy (GA) marked by regional retinal pigment epithelium (RPE) cell death or as an advanced form known as neovascular AMD marked by the intrusion of fragile new blood vessels into the normally avascular retina. Physicians have several therapeutic interventions available to combat neovascular AMD, but GA has no approved effective therapies as of yet. In this chapter, we will discuss the current strategies for limiting dry AMD in patients. We will also discuss previous attempts at pharmacological intervention that were tested in a clinical setting and consider reasons why these putative therapeutics did not perform successfully in large-scale trials. Despite the number of unsuccessful past trials, new pharmacological interventions may succeed. These future therapies may aid millions of AMD patients worldwide.
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Affiliation(s)
- Charles B Wright
- Physiology and Ophthalmology and Visual Sciences, University of Kentucky College of Medicine, Lexington, KY, 40506, USA
| | - Jayakrishna Ambati
- Physiology and Ophthalmology and Visual Sciences, University of Kentucky College of Medicine, Lexington, KY, 40506, USA.
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Cideciyan AV, Swider M, Schwartz SB, Stone EM, Jacobson SG. Predicting Progression of ABCA4-Associated Retinal Degenerations Based on Longitudinal Measurements of the Leading Disease Front. Invest Ophthalmol Vis Sci 2015; 56:5946-55. [PMID: 26377081 DOI: 10.1167/iovs.15-17698] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
PURPOSE To evaluate the progression of the earliest stage of disease in ABCA4-associated retinal degenerations (RDs). METHODS Near-infrared excited reduced-illuminance autofluorescence imaging was acquired across the retina up to 80 degrees eccentricity in 44 patients with two ABCA4 alleles. The eccentricity of the leading disease front (LDF) corresponding to the earliest stage of disease was measured along the four meridians. A mathematical model describing the expansion of the LDF was developed based on 6 years of longitudinal follow-up. RESULTS The extent of LDF along the superior, inferior, and temporal meridians showed a wide spectrum from 3.5 to 70 degrees. In patients with longitudinal data, the average centrifugal expansion rate was 2 degrees per year. The nasal extent of LDF between the fovea and ONH ranged from 4.3 to 16.5 degrees and expanded at 0.35 degrees per year. The extent of LDF beyond ONH ranged from 19 to 75 degrees and expanded on average at 2 degrees per year. A mathematical model fit well to the longitudinal data describing the expansion of the LDF. CONCLUSIONS The eccentricity of the LDF in ABCA4-RD shows a continuum from parafovea to far periphery along all four meridians consistent with a wide spectrum of severity observed clinically. The model of progression may provide a quantitative prediction of the LDF expansion based on the age and eccentricity of the LDF at a baseline visit, and thus contribute significantly to the enrollment of candidates appropriate for clinical trials planning specific interventions, efficacy outcomes, and durations.
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Affiliation(s)
- Artur V Cideciyan
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Malgorzata Swider
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Sharon B Schwartz
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Edwin M Stone
- Stephen A. Wynn Institute for Vision Research, University of Iowa, Iowa City, Iowa, United States 3Howard Hughes Medical Institute, Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, Iowa, United Sta
| | - Samuel G Jacobson
- Scheie Eye Institute Department of Ophthalmology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States
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Lim PC, Layton CJ. Prognostic implications of imaging in atrophic macular degeneration and its use in clinical practice and clinical trial design. Clin Exp Ophthalmol 2015; 44:410-21. [PMID: 26468964 DOI: 10.1111/ceo.12671] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/06/2015] [Accepted: 10/08/2015] [Indexed: 01/06/2023]
Abstract
Clinical prognostic markers in atrophic age-related macular degeneration include the extent of existing atrophy, fundus autofluorescence (FAF) patterns and optical coherence tomography changes in the outer retina/retinal pigment epithelium interface. The prognostic implications of these findings may be used to determine not just the rate of disease progression but also influence the likelihood, magnitude and clinical relevance of therapy responses. FAF phenotypes have been extensively investigated; however, the pathophysiological mechanisms behind their appearance have not been fully elucidated. Optical coherence tomography imaging is additive to FAF imaging in atrophic age-related macular degeneration, allowing the visualization of detail not available through FAF imaging whilst also displaying subtle changes correlating with the FAF phenotypes themselves, thereby giving clues to their histological determinates. The developing understanding of these imaging modalities and consequent development of prognostically useful classification systems have widespread implication in clinical care and clinical trial design.
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Affiliation(s)
- Paul Cc Lim
- School of Medicine, University of Queensland Mayne Medical School, Herston, Queensland, Australia
| | - Christopher J Layton
- School of Medicine, University of Queensland Mayne Medical School, Herston, Queensland, Australia.,Gallipoli Medical Research Institute, Newdegate St, Greenslopes Australia, Greenslopes Private Hospital, Greenslopes, Queensland, Australia.,Ophthalmology Department, Greenslopes Private Hospital, Brisbane, Queensland, Australia
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Bioanalysis of emixustat (ACU-4429) in whole blood collected with volumetric absorptive microsampling by LC–MS/MS. Bioanalysis 2015; 7:2071-83. [DOI: 10.4155/bio.15.125] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Background: A method to quantify emixustat (an investigational drug agent) in human blood collected using volumetric absorptive microsampling (VAMS) could be more practical for sample collection at sites with limited facilities for processing and storage of plasma. Methods: A LC–MS/MS method was developed and evaluated for accuracy and precision, linearity, carryover, selectivity, recovery, matrix effects, hematocrit effects and stability. Results: Core validation parameters met acceptance criteria within the normal ranges of hematocrit levels for adults (30–55%). Stability of emixustat in blood collected with and without anticoagulant (NaF/KOx) on the VAMS device at ambient, refrigerated and frozen conditions was established. Conclusion: The method has been validated and is suitable for the bioanalysis of emixustat in human blood collected by VAMS.
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