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Kiraly P, Cottriall CL, Taylor LJ, Jolly JK, Cehajic-Kapetanovic J, Yusuf IH, Martinez-Fernandez de la Camara C, Shanks M, Downes SM, MacLaren RE, Fischer MD. Outcomes and Adverse Effects of Voretigene Neparvovec Treatment for Biallelic RPE65-Mediated Inherited Retinal Dystrophies in a Cohort of Patients from a Single Center. Biomolecules 2023; 13:1484. [PMID: 37892166 PMCID: PMC10605275 DOI: 10.3390/biom13101484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 09/27/2023] [Accepted: 10/04/2023] [Indexed: 10/29/2023] Open
Abstract
Our study evaluated the morphological and functional outcomes, and the side effects, of voretigene neparvovec (VN) gene therapy for RPE65-mediated inherited retinal dystrophies (IRDs) in 12 eyes (six patients) at the Oxford Eye Hospital with a mean follow-up duration of 8.2 (range 1-12) months. All patients reported a subjective vision improvement 1 month after gene therapy. Best-corrected visual acuity (BCVA) remained stable (baseline: 1.28 (±0.71) vs. last follow-up: 1.46 (±0.60); p = 0.25). Average white Full-Field Stimulus Testing (FST) showed a trend towards improvement (baseline: -4.41 (±10.62) dB vs. last follow-up: -11.98 (±13.83) dB; p = 0.18). No changes in central retinal thickness or macular volume were observed. The side effects included mild intraocular inflammation (two eyes) and cataracts (four eyes). Retinal atrophy occurred in 10 eyes (eight mild, two severe) but did not impact FST measurements during the follow-up period. Increased intraocular pressure (IOP) was noted in three patients (six eyes); four eyes (two patients) required glaucoma surgery. The overall safety and effectiveness of VN treatment in our cohort align with previous VN clinical trials, except for the higher occurrence of retinal atrophy and increased IOP in our cohort. This suggests that raised IOP and retinal atrophy may be more common than previously reported.
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Affiliation(s)
- Peter Kiraly
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (P.K.); (J.C.-K.); (I.H.Y.); (C.M.-F.d.l.C.); (S.M.D.); (R.E.M.)
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
| | - Charles L. Cottriall
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (P.K.); (J.C.-K.); (I.H.Y.); (C.M.-F.d.l.C.); (S.M.D.); (R.E.M.)
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
| | - Laura J. Taylor
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (P.K.); (J.C.-K.); (I.H.Y.); (C.M.-F.d.l.C.); (S.M.D.); (R.E.M.)
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
| | - Jasleen K. Jolly
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
- Vision and Eye Research Institute, Anglia Ruskin University, Cambridge CB1 1PT, UK
| | - Jasmina Cehajic-Kapetanovic
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (P.K.); (J.C.-K.); (I.H.Y.); (C.M.-F.d.l.C.); (S.M.D.); (R.E.M.)
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
| | - Imran H. Yusuf
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (P.K.); (J.C.-K.); (I.H.Y.); (C.M.-F.d.l.C.); (S.M.D.); (R.E.M.)
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
| | - Cristina Martinez-Fernandez de la Camara
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (P.K.); (J.C.-K.); (I.H.Y.); (C.M.-F.d.l.C.); (S.M.D.); (R.E.M.)
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
| | - Morag Shanks
- Oxford Regional Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK;
| | - Susan M. Downes
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (P.K.); (J.C.-K.); (I.H.Y.); (C.M.-F.d.l.C.); (S.M.D.); (R.E.M.)
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
| | - Robert E. MacLaren
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (P.K.); (J.C.-K.); (I.H.Y.); (C.M.-F.d.l.C.); (S.M.D.); (R.E.M.)
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
| | - M. Dominik Fischer
- Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford OX3 9DU, UK; (P.K.); (J.C.-K.); (I.H.Y.); (C.M.-F.d.l.C.); (S.M.D.); (R.E.M.)
- Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, UK;
- Centre for Ophthalmology, University Hospital Tubingen, 72076 Tubingen, Germany
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Cehajic-Kapetanovic J, Cottriall CL, Jolly JK, Shanks M, Clouston P, Charbel Issa P, MacLaren RE. Electrophysiological verification of enhanced S-cone syndrome caused by a novel c.755T>C NR2E3 missense variant. Ophthalmic Genet 2019; 40:29-33. [PMID: 30466340 DOI: 10.1080/13816810.2018.1547912] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Nuclear hormone receptor gene, NR2E3, plays a critical role in retinogenesis and determination of the rod photoreceptor phenotype. Mutations in NR2E3 typically lead to recessive enhanced S-cone syndrome (ESCS), where affected individuals show higher sensitivity to short wavelength light and early onset rod dysfunction. Patients with ESCS present in early childhood with nyctalopia, enhanced sensitivity to blue light and display a very heterogeneic retinal phenotype with varying degrees of clumped pigmentation and occasional retinoschisis. PURPOSE To confirm the pathogenicity of a novel mutation in NR2E3 using electrophysiological studies. MATERIALS AND METHODS Patient underwent detailed clinical evaluation and ophthalmic imaging followed by next generation sequencing analysis and electrophysiological studies. RESULTS We describe a case of a young man of Greek descent with a family history of retinal degeneration. His fundal features at presentation were atypical of ESCS, with striking macular involvement in both eyes, including fibrotic subretinal material overlying the pigment epithelial detachment in one eye and schisis in the other. Genetic testing revealed a novel homozygous variant in NR2E3 gene of uncertain pathogenicity. Instead of performing further genetic analyses, electrophysiological studies showed pathognomonic changes in the S-cone response. CONCLUSIONS With the recent clinical endorsement of a gene therapy for RPE65 related-inherited retinal degeneration it is of paramount importance to correctly identify the pathogenic genetic mutation. In this particular syndrome, we highlight the value of electrophysiology to confirm the pathogenicity of a novel mutation in NR2E3 and aid the diagnosis of ESCS, with potential for gene therapy in the future.
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Affiliation(s)
- Jasmina Cehajic-Kapetanovic
- a Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences , Oxford University , Oxford , UK
- b Oxford Eye Hospital , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
| | - Charles L Cottriall
- a Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences , Oxford University , Oxford , UK
- b Oxford Eye Hospital , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
| | - Jasleen K Jolly
- a Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences , Oxford University , Oxford , UK
- b Oxford Eye Hospital , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
| | - Morag Shanks
- c Oxford Medical Genetics Laboratories , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
| | - Penny Clouston
- c Oxford Medical Genetics Laboratories , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
| | - Peter Charbel Issa
- a Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences , Oxford University , Oxford , UK
- b Oxford Eye Hospital , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
| | - Robert E MacLaren
- a Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences , Oxford University , Oxford , UK
- b Oxford Eye Hospital , Oxford University Hospitals NHS Foundation Trust , Oxford , UK
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McKee JB, Cottriall CL, Elston J, Epps S, Evangelou N, Gerry S, Kennard C, Kong Y, Koelewyn A, Kueker W, Leite MI, Palace J, Craner M. Amiloride does not protect retinal nerve fibre layer thickness in optic neuritis in a phase 2 randomised controlled trial. Mult Scler 2017; 25:246-255. [PMID: 29172994 DOI: 10.1177/1352458517742979] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
BACKGROUND Recent basic and clinical evidence suggests amiloride may be neuroprotective in multiple sclerosis (MS) through the blockade of the acid sensing ion channel (ASIC). OBJECTIVE To examine the neuroprotective efficacy of amiloride in acute optic neuritis (ON). METHODS A total of 48 patients were recruited to a phase 2, double blind, single site, randomised controlled trial. Scanning laser polarimetry (GDx) at 6 months was the primary outcome measure and optical coherence tomography (OCT) and visual and electrophysiological measures were secondary outcome measures. Participants aged 18-55 years, ≤28 days of onset of first episode unilateral ON, were randomised to amiloride (10 mg daily for 5 months) or placebo ( clinicaltrials.gov , NCT 01802489). RESULTS Intention-to-treat (ITT) cohort consisted of 43 patients; 23 placebo and 20 amiloride. No significant drug-related adverse events occurred. No significant differences were found in GDx ( p = 0.840). Visual evoked potentials (VEP) were significantly prolonged in the amiloride group compared to placebo ( p = 0.004). All other secondary outcome measures showed no significant difference. Baseline analysis of OCT data demonstrated a significant pre-randomisation thinning of ganglion cell layer. CONCLUSION Amiloride has not demonstrated any neuroprotective benefit within this trial paradigm, but future neuroprotective trials in ON should target the window of opportunity to maximise potential neuroprotective benefit.
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Affiliation(s)
- Justin B McKee
- Division of Clinical Neurology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK/The Princess Alexandra Eye Pavilion, NHS Lothian, Edinburgh, UK
| | - Charles L Cottriall
- The Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - John Elston
- The Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Simon Epps
- Ophthalmology, School of Clinical Sciences, University of Bristol, Bristol, UK
| | - Nikos Evangelou
- Faculty of Medicine and Health Sciences, University of Nottingham, Nottingham, UK
| | - Stephen Gerry
- Centre for Statistics in Medicine, University of Oxford, Oxford, UK
| | - Christopher Kennard
- Medical Sciences Division, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Yazhuo Kong
- Oxford Centre for Functional Magnetic Resonance Imaging of the Brain (FMRIB), Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK/Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Abigail Koelewyn
- Division of Clinical Neurology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Wilhelm Kueker
- Department of Neuroradiology, John Radcliffe Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Maria Isabel Leite
- Division of Clinical Neurology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Jacqueline Palace
- Division of Clinical Neurology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
| | - Matthew Craner
- Division of Clinical Neurology, Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, University of Oxford, Oxford, UK
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Stingl K, Schippert R, Bartz-Schmidt KU, Besch D, Cottriall CL, Edwards TL, Gekeler F, Greppmaier U, Kiel K, Koitschev A, Kühlewein L, MacLaren RE, Ramsden JD, Roider J, Rothermel A, Sachs H, Schröder GS, Tode J, Troelenberg N, Zrenner E. Interim Results of a Multicenter Trial with the New Electronic Subretinal Implant Alpha AMS in 15 Patients Blind from Inherited Retinal Degenerations. Front Neurosci 2017; 11:445. [PMID: 28878616 PMCID: PMC5572402 DOI: 10.3389/fnins.2017.00445] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Accepted: 07/20/2017] [Indexed: 11/13/2022] Open
Abstract
Purpose: We assessed the safety and efficacy of a technically advanced subretinal electronic implant, RETINA IMPLANT Alpha AMS, in end stage retinal degeneration in an interim analysis of two ongoing prospective clinical trials. The purpose of this article is to describe the interim functional results (efficacy). Methods: The subretinal visual prosthesis RETINA IMPLANT Alpha AMS (Retina Implant AG, Reutlingen, Germany) was implanted in 15 blind patients with hereditary retinal degenerations at four study sites with a follow-up period of 12 months (www.clinicaltrials.gov NCT01024803 and NCT02720640). Functional outcome measures included (1) screen-based standardized 2- or 4-alternative forced-choice (AFC) tests of light perception, light localization, grating detection (basic grating acuity (BaGA) test), and Landolt C-rings; (2) gray level discrimination; (3) performance during activities of daily living (ADL-table tasks). Results: Implant-mediated light perception was observed in 13/15 patients. During the observation period implant mediated localization of visual targets was possible in 13/15 patients. Correct grating detection was achieved for spatial frequencies of 0.1 cpd (cycles per degree) in 4/15; 0.33 cpd in 3/15; 0.66 cpd in 2/15; 1.0 cpd in 2/15 and 3.3 cpd in 1/15 patients. In two patients visual acuity (VA) assessed with Landolt C- rings was 20/546 and 20/1111. Of 6 possible gray levels on average 4.6 ± 0.8 (mean ± SD, n = 10) were discerned. Improvements (power ON vs. OFF) of ADL table tasks were measured in 13/15 patients. Overall, results were stable during the observation period. Serious adverse events (SAEs) were reported in 4 patients: 2 movements of the implant, readjusted in a second surgery; 4 conjunctival erosion/dehiscence, successfully treated; 1 pain event around the coil, successfully treated; 1 partial reduction of silicone oil tamponade leading to distorted vision (silicon oil successfully refilled). The majority of adverse events (AEs) were transient and mostly of mild to moderate intensity. Conclusions: Psychophysical and subjective data show that RETINA IMPLANT Alpha AMS is reliable, well tolerated and can restore limited visual functions in blind patients with degenerations of the outer retina. Compared with the previous implant Alpha IMS, longevity of the new implant Alpha AMS has been considerably improved. Alpha AMS has meanwhile been certified as a commercially available medical device, reimbursed in Germany by the public health system.
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Affiliation(s)
- Katarina Stingl
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany
| | | | | | - Dorothea Besch
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany
| | - Charles L Cottriall
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, University of OxfordOxford, United Kingdom
| | - Thomas L Edwards
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, University of OxfordOxford, United Kingdom
| | - Florian Gekeler
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany.,Department of Ophthalmology, Katharinenhospital, Klinikum StuttgartStuttgart, Germany
| | | | - Katja Kiel
- Städtisches Klinikum Dresden Friedrichstadt, University Teaching HospitalDresden, Germany
| | - Assen Koitschev
- Division Pediatric Otorhinolaryngology and Otology - Olgahospital, Department of Otorhinolaryngology, Klinikum StuttgartStuttgart, Germany
| | - Laura Kühlewein
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany
| | - Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, University of OxfordOxford, United Kingdom
| | - James D Ramsden
- Nuffield Laboratory of Ophthalmology, Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, University of OxfordOxford, United Kingdom
| | - Johann Roider
- Department of Ophthalmology, University of KielKiel, Germany
| | | | - Helmut Sachs
- Städtisches Klinikum Dresden Friedrichstadt, University Teaching HospitalDresden, Germany
| | | | - Jan Tode
- Department of Ophthalmology, University of KielKiel, Germany
| | | | - Eberhart Zrenner
- Centre for Ophthalmology, University of TuebingenTuebingen, Germany.,Werner Reichardt Centre for Integrative Neuroscience, University of TuebingenTuebingen, Germany
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Edwards TL, Jolly JK, Groppe M, Barnard AR, Cottriall CL, Tolmachova T, Black GC, Webster AR, Lotery AJ, Holder GE, Xue K, Downes SM, Simunovic MP, Seabra MC, MacLaren RE. Visual Acuity after Retinal Gene Therapy for Choroideremia. N Engl J Med 2016; 374:1996-8. [PMID: 27120491 PMCID: PMC4996318 DOI: 10.1056/nejmc1509501] [Citation(s) in RCA: 157] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
| | | | | | | | | | | | | | - Andrew R Webster
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | | | - Graham E Holder
- Moorfields Eye Hospital NHS Foundation Trust, London, United Kingdom
| | - Kanmin Xue
- University of Oxford, Oxford, United Kingdom
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Stingl K, Bartz-Schmidt KU, Besch D, Chee CK, Cottriall CL, Gekeler F, Groppe M, Jackson TL, MacLaren RE, Koitschev A, Kusnyerik A, Neffendorf J, Nemeth J, Naeem MAN, Peters T, Ramsden JD, Sachs H, Simpson A, Singh MS, Wilhelm B, Wong D, Zrenner E. Subretinal Visual Implant Alpha IMS--Clinical trial interim report. Vision Res 2015; 111:149-60. [PMID: 25812924 DOI: 10.1016/j.visres.2015.03.001] [Citation(s) in RCA: 224] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 02/18/2015] [Accepted: 03/02/2015] [Indexed: 11/27/2022]
Abstract
A subretinal visual implant (Alpha IMS, Retina Implant AG, Reutlingen, Germany) was implanted in 29 blind participants with outer retinal degeneration in an international multicenter clinical trial. Primary efficacy endpoints of the study protocol were a significant improvement of activities of daily living and mobility to be assessed by activities of daily living tasks, recognition tasks, mobility, or a combination thereof. Secondary efficacy endpoints were a significant improvement of visual acuity/light perception and/or object recognition (clinicaltrials.gov, NCT01024803). During up to 12 months observation time twenty-one participants (72%) reached the primary endpoints, of which thirteen participants (45%) reported restoration of visual function which they use in daily life. Additionally, detection, localization, and identification of objects were significantly better with the implant power switched on in the first 3 months. Twenty-five participants (86%) reached the secondary endpoints. Measurable grating acuity was up to 3.3 cycles per degree, visual acuities using standardized Landolt C-rings were 20/2000, 20/2000, 20/606 and 20/546. Maximal correct motion perception ranged from 3 to 35 degrees per second. These results show that subretinal implants can restore very-low-vision or low vision in blind (light perception or less) patients with end-stage hereditary retinal degenerations.
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Affiliation(s)
- Katarina Stingl
- Centre for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany
| | | | - Dorothea Besch
- Centre for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany
| | - Caroline K Chee
- Department of Ophthalmology, National University Health System, 1E Kent Ridge Road, Singapore 119228, Singapore
| | - Charles L Cottriall
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Florian Gekeler
- Centre for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany; Klinikum Stuttgart - Katharinenhospital, Eye Clinic, Kriegsbergstraße 60, 70174 Stuttgart, Germany(1)
| | - Markus Groppe
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Timothy L Jackson
- King's College Hospital and King's College London, Denmark Hill, London SE5 9RS, United Kingdom
| | - Robert E MacLaren
- Oxford Eye Hospital and Nuffield Laboratory of Ophthalmology, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Assen Koitschev
- Klinikum Stuttgart - Olgahospital, ORL-Department, Pediatric Otorhinolaryngology and Otology, Kriegsbergstr. 62, 70176 Stuttgart, Germany
| | - Akos Kusnyerik
- Department of Ophthalmology, Semmelweis University, Maria utca 39, H-1085 Budapest, Hungary
| | - James Neffendorf
- King's College Hospital and King's College London, Denmark Hill, London SE5 9RS, United Kingdom
| | - Janos Nemeth
- Department of Ophthalmology, Semmelweis University, Maria utca 39, H-1085 Budapest, Hungary
| | - Mohamed Adheem Naser Naeem
- Department of Ophthalmology, National University Health System, 1E Kent Ridge Road, Singapore 119228, Singapore
| | - Tobias Peters
- STZ Eyetrial, Center for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany
| | - James D Ramsden
- Department of Otolaryngology, Oxford University Hospitals NHS Trust, Oxford OX3 9DU, United Kingdom
| | - Helmut Sachs
- Klinikum Dresden Friedrichstadt, Univ. Teaching Hospital, Eye Clinic, Friedrichstr. 41, 01067 Dresden, Germany
| | - Andrew Simpson
- King's College Hospital and King's College London, Denmark Hill, London SE5 9RS, United Kingdom
| | - Mandeep S Singh
- Department of Ophthalmology, National University Health System, 1E Kent Ridge Road, Singapore 119228, Singapore
| | - Barbara Wilhelm
- STZ Eyetrial, Center for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany
| | - David Wong
- Li Ka Shing Faculty of Medicine, University of Hong Kong, 301 Block B, Cyberport 4, Hong Kong
| | - Eberhart Zrenner
- Werner Reichardt Centre for Integrative Neuroscience (CIN), University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany; Centre for Ophthalmology, University of Tübingen, Schleichstr. 12-16, 72076 Tübingen, Germany.
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MacLaren RE, Groppe M, Barnard AR, Cottriall CL, Tolmachova T, Seymour L, Clark KR, During MJ, Cremers FPM, Black GCM, Lotery AJ, Downes SM, Webster AR, Seabra MC. Retinal gene therapy in patients with choroideremia: initial findings from a phase 1/2 clinical trial. Lancet 2014; 383:1129-37. [PMID: 24439297 PMCID: PMC4171740 DOI: 10.1016/s0140-6736(13)62117-0] [Citation(s) in RCA: 576] [Impact Index Per Article: 57.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Choroideremia is an X-linked recessive disease that leads to blindness due to mutations in the CHM gene, which encodes the Rab escort protein 1 (REP1). We assessed the effects of retinal gene therapy with an adeno-associated viral (AAV) vector encoding REP1 (AAV.REP1) in patients with this disease. METHODS In a multicentre clinical trial, six male patients (aged 35-63 years) with choroideremia were administered AAV.REP1 (0·6-1·0×10(10) genome particles, subfoveal injection). Visual function tests included best corrected visual acuity, microperimetry, and retinal sensitivity tests for comparison of baseline values with 6 months after surgery. This study is registered with ClinicalTrials.gov, number NCT01461213. FINDINGS Despite undergoing retinal detachment, which normally reduces vision, two patients with advanced choroideremia who had low baseline best corrected visual acuity gained 21 letters and 11 letters (more than two and four lines of vision). Four other patients with near normal best corrected visual acuity at baseline recovered to within one to three letters. Mean gain in visual acuity overall was 3·8 letters (SE 4·1). Maximal sensitivity measured with dark-adapted microperimetry increased in the treated eyes from 23·0 dB (SE 1·1) at baseline to 25·3 dB (1·3) after treatment (increase 2·3 dB [95% CI 0·8-3·8]). In all patients, over the 6 months, the increase in retinal sensitivity in the treated eyes (mean 1·7 [SE 1·0]) was correlated with the vector dose administered per mm(2) of surviving retina (r=0·82, p=0·04). By contrast, small non-significant reductions (p>0·05) were noted in the control eyes in both maximal sensitivity (-0·8 dB [1·5]) and mean sensitivity (-1·6 dB [0·9]). One patient in whom the vector was not administered to the fovea re-established variable eccentric fixation that included the ectopic island of surviving retinal pigment epithelium that had been exposed to vector. INTERPRETATION The initial results of this retinal gene therapy trial are consistent with improved rod and cone function that overcome any negative effects of retinal detachment. These findings lend support to further assessment of gene therapy in the treatment of choroideremia and other diseases, such as age-related macular degeneration, for which intervention should ideally be applied before the onset of retinal thinning. FUNDING UK Department of Health and Wellcome Trust.
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Affiliation(s)
- Robert E MacLaren
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Trust and NIHR Biomedical Research Centre, Oxford, UK; Moorfields Eye Hospital NHS Foundation Trust and NIHR Ophthalmology Biomedical Research Centre, London, UK.
| | - Markus Groppe
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Trust and NIHR Biomedical Research Centre, Oxford, UK; Moorfields Eye Hospital NHS Foundation Trust and NIHR Ophthalmology Biomedical Research Centre, London, UK
| | - Alun R Barnard
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Charles L Cottriall
- Oxford Eye Hospital, Oxford University Hospitals NHS Trust and NIHR Biomedical Research Centre, Oxford, UK
| | - Tanya Tolmachova
- Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London, UK
| | - Len Seymour
- Department of Oncology, University of Oxford, Oxford, UK
| | - K Reed Clark
- Research Institute at the Nationwide Children's Hospital, Columbus, OH, USA
| | - Matthew J During
- College of Medicine, Ohio State University Medical Center, Columbus, OH, USA
| | - Frans P M Cremers
- Department of Human Genetics and Nijmegen Center for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, Netherlands
| | - Graeme C M Black
- Manchester Centre for Genomic Medicine, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Sciences Centre, St Mary's Hospital, Manchester, UK
| | - Andrew J Lotery
- Clinical Neurosciences Group, Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, UK
| | - Susan M Downes
- Nuffield Laboratory of Ophthalmology, Department of Clinical Neurosciences, University of Oxford, Oxford, UK; Oxford Eye Hospital, Oxford University Hospitals NHS Trust and NIHR Biomedical Research Centre, Oxford, UK
| | - Andrew R Webster
- Moorfields Eye Hospital NHS Foundation Trust and NIHR Ophthalmology Biomedical Research Centre, London, UK; UCL Institute of Ophthalmology, London, UK
| | - Miguel C Seabra
- Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London, UK; Chronic Diseases Research Centre, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisbon, Portugal
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8
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Vessey KA, Cottriall CL, McBrien NA. Muscarinic receptor protein expression in the ocular tissues of the chick during normal and myopic eye development. Brain Res Dev Brain Res 2002; 135:79-86. [PMID: 11978396 DOI: 10.1016/s0165-3806(02)00309-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Muscarinic receptor signalling has been implicated in both the embryonic and postnatal development of ocular structures as well as in myopic eye growth. A radioligand binding assay was used to determine whether changes in muscarinic receptor density and/or affinity occurred in the chick retina, choroid and sclera during early post-hatching development or with the induction of myopia. Specific receptor binding sites were saturable with increasing concentrations of the muscarinic receptor ligand [3H]N-methyl-scopolamine in the retina and choroid but not in the sclera. In normal eyes, binding density in the retina was not altered from age P5 to P10 (447+/-14 vs. 411+/-13 fmol/mg of protein, P=0.07). However, in the choroid, the number of receptor binding sites significantly increased between P5 and P10 (637+/-39 vs. 1125+/-121 fmol/mg of protein, P<0.01). Binding affinity (K(D)) was not altered with age in either the retina or choroid. Myopia was induced in chicks by deprivation of form vision, using translucent diffusers, from age P3. Despite the induction of significant degrees of ocular elongation and myopia at P5 (-8.7+/-0.3 D, P<0.01) and P10 (-22.5+/-1.3 D, P<0.01), neither muscarinic receptor density nor affinity were altered in the retina or choroid of myopic eyes. These findings indicate that regulation of muscarinic receptor numbers in the chick choroid is occurring in normal post-hatching development of this tissue. However, myopic eye enlargement was not associated with changes in muscarinic receptor protein expression in the chick retina and choroid.
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Affiliation(s)
- Kirstan A Vessey
- Department of Optometry and Vision Sciences, The University of Melbourne, Melbourne, Vic. 3010, Australia
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9
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Abstract
Whilst the precise mechanism regulating ocular growth is unknown, it has been shown that various pharmacological agents, including the muscarinic receptor antagonists, atropine and pirenzepine, are effective at preventing the development of myopia. A recent study, which demonstrated that muscarinic antagonists reduce the synthesis of glycosaminoglycans and DNA in chick sclera in vitro, led to the suggestion that such drugs may act directly on the sclera, possibly through a toxic mechanism. Accepted markers of scleral metabolism and cell viability were used in conjunction with a non-invasive, physiological method of ocular growth regulation to determine whether the selective muscarinic antagonist pirenzepine inhibits the development of myopia via toxicity to the sclera. Chicks were monocularly deprived (MD) of pattern vision and given daily intravitreal injections of either pirenzepine (700 microg) or saline vehicle into the deprived eye over 5 days. Unoccluded animals also received intravitreal injections of either pirenzepine or saline into one eye (n=6, all groups). The contralateral eye of all animals was left untreated for comparison. Optical and ocular biometric measures were collected on the final experimental day. Following in vivo delivery of [(35)S] labelled sulphate, levels of sulphate incorporation into scleral glycosaminoglycans were measured in proteinase K digests following selective precipitation with alcian blue dye. The DNA content was also assessed through luminescence spectrometry after binding to Hoechst 33258 dye. To allow comparison with an accepted non-invasive, physiological method of ocular growth regulation, myopia was prevented in additional groups of MD animals by allowing 3hr of unoccluded vision each day, over 5 days, before levels of sulphate incorporation were measured. Scleral DNA content, a marker of cell viability, was not significantly altered between treated and control eyes in any injected group. Relative levels of sulphate incorporation (% difference between treated and contralateral control eyes) were significantly lower in the cartilaginous sclera of pirenzepine-MD animals, compared to saline-MD controls (+35.9 +/- 10.1% vs +121.2 +/- 28.6%, P<0.05), after 2hr of incorporation. However, after 6hr incorporation, there was no significant difference in sulphate incorporation in the cartilaginous sclera between the two groups (+87.2 +/- 33.1% vs +111.0 +/- 14.4%, P=0.53). No significant change was found in the levels of glycosaminoglycan synthesis in the fibrous sclera of any pirenzepine treated group, when compared to the appropriate saline control. Relative patterns of sulphate incorporation, between treatment and control groups, were essentially identical at both time points examined, regardless of whether myopia was prevented through pirenzepine injection or periods of unoccluded vision. The present study shows that, at a dose of pirenzepine sufficient to prevent experimentally-induced axial myopia, glycosaminoglycan synthesis in the cartilaginous sclera was significantly reduced for a transient period following the injection. These pirenzepine-induced reductions in glycosaminoglycan synthesis were not caused by direct drug toxicity to scleral cells as these changes were reversible and no significant reduction in DNA content was observed in pirenzepine treated eyes. Similar patterns of scleral glycosaminoglycan synthesis changes were found following the provision of brief periods of unoccluded vision further demonstrating that pirenzepine is effective in myopia prevention via a non-toxic mechanism. Consequently, the prevention of myopia development in chicks, with either pirenzepine or brief periods of unoccluded vision, is associated with the transient modulation of scleral glycosaminoglycan synthesis in the cartilaginous sclera.
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Affiliation(s)
- Hue-Trung Truong
- Department of Optometry and Vision Sciences, The University of Melbourne, Victoria, 3010, Australia
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10
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Cottriall CL, Brew J, Vessey KA, McBrien NA. Diisopropylfluorophosphate alters retinal neurotransmitter levels and reduces experimentally-induced myopia. Naunyn-Schmiedeberg's Archives of Pharmacology 2001; 364:372-82. [PMID: 11683525 DOI: 10.1007/s002100100460] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The excessive enlargement of the eye seen in myopia is known to be regulated, in part, by retinal neurotransmitters. One excitatory retinal neurotransmitter, acetylcholine, has been implicated in the signal cascade through the effectiveness of the muscarinic antagonist, atropine, in preventing myopia development. The present study therefore examined whether an indirect cholinomimetic, diisopropylfluorophosphate (DFP), could increase the level of experimental myopia, induced by the deprivation of pattern vision. Injections of either phosphate-buffered DFP or phosphate-buffered saline were made every 48 h into the vitreous chamber of one eye of chicks. The injected eye was then deprived of pattern vision by a translucent occluder. The fellow eye remained untreated and acted as a genetic control. At the end of the treatment period (8 days) axial ocular dimensions and cycloplegic refractive error were measured. To investigate the effects of DFP on retinal neurotransmitter levels, measurements of acetylcholine and dopamine contents were made on retinal tissue following either a single or multiple DFP injections, using reverse phase high performance liquid chromatography (HPLC). Rather than potentiating myopia and vitreous chamber elongation, a significant reduction in myopia (58%) was observed in DFP-injected deprived eyes, compared to saline controls. However, open eyes injected with DFP showed no difference in refraction or vitreous chamber depth compared to contralateral control eyes or saline controls. HPLC analysis revealed increased steady-state content of acetylcholine (+34 +/- 6 ng/mg protein, mean +/- SEM, P<0.01, equivalent to a 54% increase) and dopamine (+377 +/- 83 pg/mg protein, P<0.01, a 36% increase) in DFP-treated eyes compared to contralateral control eyes following a single DFP injection. No changes in either acetylcholine or dopamine content were found in saline-treated control animals. Injection of dopamine antagonists, in combination with DFP, indicated that the DFP-induced reduction in myopia is mediated, at least in part, through a D2 receptor mechanism. Findings argue against a direct cholinergic 'stop-go' pathway controlling ocular growth. Instead the reduction of induced myopia could be related to the action of DFP (directly or indirectly) on dopamine levels in the retina.
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Affiliation(s)
- C L Cottriall
- Department of Optometry and Vision Sciences, University of Melbourne, Victoria, Australia
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11
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Abstract
The success of the M(1)-selective muscarinic antagonist pirenzepine in preventing myopia development in animal models implicates a role for the M(1) receptor. However, the relatively high dose of pirenzepine required may indicate that the drug acts through another receptor subtype. This study examined whether the M(4)-selective antagonist, himbacine, could also prevent myopia. Daily intravitreal injections of himbacine inhibited the inducement of myopia in chick eyes in a dose- dependent manner. Doses < or = 200 microg caused no significant inhibition of induced myopia compared to controls (-13.7 +/- 2.3 vs -16.2 +/- 0.9D, ANOVA p = 0.37), whilst a dose of 800 microg almost completely inhibited the induced myopia (-2.4 +/- 2.0, p < 0.01). Findings demonstrate himbacine is effective at preventing the development of myopia in chick and implicates a role for the M4 receptor.
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Affiliation(s)
- C L Cottriall
- Department of Optometry and Vision Sciences, University of Melbourne, Victoria 3010, Australia
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12
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Abstract
Retinal neurotransmitters are known to play a role in postnatal ocular development and eye growth. The success of muscarinic antagonists in blocking form-deprivation myopia has implicated retinal acetylcholine in the control of ocular growth. The present study investigated whether steady-state content of acetylcholine (ACh) and its metabolite choline (Ch) are altered in the retina of eyes developing axial myopia, in both tree shrews and chicks. Retinal ACh and Ch content were measured using reverse-phase high-performance liquid chromatography. Posterior and anterior retinal samples were analyzed from myopic (form deprived) and control eyes as well as age-matched normal eyes. Normative data on retinal neurotransmitter content demonstrated that chick retinas contained less than half the ACh and Ch neurotransmitter content of tree shrews when normalized to retinal protein (ACh: 61 +/- 3 vs. 130 +/- 6 ng, Ch: 131 +/- 5 vs. 347 +/- 25 ng). There was no significant difference in either ACh or Ch content between myopic and contralateral control eyes in either tree shrews or chicks, irrespective of the degree of myopia. This finding was consistent for both posterior, anterior, and consequently whole retinal samples. In contrast, dopamine and DOPAC contents were found to be reduced in myopic compared to control eyes of the same tree shrews (dopamine -6.9% and DOPAC -15.5%) and chicks (dopamine -12.3% and DOPAC -28.2%). These findings demonstrate that, contrary to dopamine and DOPAC content, steady-state retinal acetylcholine and choline content is not significantly altered during myopia development.
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Affiliation(s)
- N A McBrien
- Department of Optometry and Vision Sciences, The University of Melbourne, Victoria, Australia.
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13
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Cottriall CL, McBrien NA, Annies R, Leech EM. Prevention of form-deprivation myopia with pirenzepine: a study of drug delivery and distribution. Ophthalmic Physiol Opt 1999; 19:327-35. [PMID: 10645389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The present study investigated the drug distribution and elimination profiles in ocular tissues of pirenzepine, a selective M1 muscarinic antagonist known to inhibit myopia. Results demonstrate that (1) Intravitreal injections of the M1 selective antagonist pirenzepine were more effective at preventing form-deprivation myopia than subconjunctival injections. (2) Maximum drug levels were reached within 1 hr for both retina and sclera following intravitreal (28 and 11 nanomole) and subconjunctival (0.25 and 1 nanomole) injection. Intravitreal injection proved a more effective route of drug delivery to all ocular tissues compared to subconjunctival injection. (3) Elimination times of pirenzepine from ocular tissues were much shorter than those reported for blood plasma. (4) Histological examination revealed no evidence of gross toxic effects at doses effective in inhibiting induced axial myopia. In conclusion, pirenzepine was effective at reducing form-deprivation myopia in a dose-dependent manner with no evidence of disruption to the retina. However, results were not conclusive as to where pirenzepine may have its site of action in preventing form-deprivation myopia.
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Affiliation(s)
- C L Cottriall
- Department of Optometry and Vision Sciences, University of Melbourne, Parkville, Victoria, UK
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14
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Cottriall CL, McBrien NA. The M1 muscarinic antagonist pirenzepine reduces myopia and eye enlargement in the tree shrew. Invest Ophthalmol Vis Sci 1996; 37:1368-79. [PMID: 8641840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
PURPOSE To determine the efficacy of the M1-selective muscarinic antagonist, pirenzepine, in preventing experimentally induced myopia in a mammalian model, the tree shrew. METHODS Tree shrews were monocularly deprived (MD) using translucent goggles or negative lenses for a period of 12 days. In two of the MD groups, tree shrews received daily subconjunctival administration of either pirenzepine (17.7 mumol; n = 9) or vehicle control (n = 6). Control groups (n = 6) were used to assess the effects of MD, injection regimen, and drug effects. RESULTS In sham-injected and saline-injected MD tree shrews, 12 days of MD produced-13.2 D +/- 0.8 D and -14.1 D +/- 0.5 D of axial myopia, respectively. In pirenzepine-injected MD tree shrews, 12 days of MD induced an axial myopia of only -2.1 D +/- 1.4 D. The significant reduction in myopia in pirenzepine-injected MD tree shrews was caused by significantly less vitreous chamber elongation of the deprived eye (0.05 mm +/- 0.04 mm) relative to the contralateral control eye when compared to sham-injected and saline-injected MD tree shrews (0.24 mm +/- 0.02 mm and 0.29 mm +/- 0.01 mm). Mean equatorial enlargement and increased eye weight were prevented in pirenzepine-injected MD tree shrews (P < 0.01). Pirenzepine also was found to reduce myopia and ocular enlargement in lens defocus-induced myopia. Control experiments demonstrated that pirenzepine did not cause a significant reduction in amplitude of carbachol-induced accommodation. CONCLUSIONS Findings demonstrate that chronic administration of the M1-selective muscarinic antagonist, pirenzepine, prevents experimentally induced myopia in this mammalian model by a nonaccommodative mechanism.
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Affiliation(s)
- C L Cottriall
- Department of Optometry and Vision Sciences, University of Wales, Cardiff, United Kingdom
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Leech EM, Cottriall CL, McBrien NA. Pirenzepine prevents form deprivation myopia in a dose dependent manner. Ophthalmic Physiol Opt 1995; 15:351-6. [PMID: 8524553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Previous studies have demonstrated that muscarinic antagonists, such as atropine and pirenzepine, block form deprivation myopia in avian and mammalian models. The aim of the present investigation was to establish dose-response curves for intravitreal and subconjunctivally injected pirenzepine and to determine receptor specificity. Chicks were monocularly deprived of form vision for five days and received daily injections of either pirenzepine or saline. Keratometry, retinoscopy and A-scan ultrasonography of axial ocular dimensions were then taken. Intravitreally injected pirenzepine was effective at preventing form deprivation myopia in a dose dependent manner with an ED50 of 175 micrograms. A 500 micrograms dose totally prevented induced myopia (+0.9 D versus -13.7 D) and axial enlargement (-0.14 mm versus +0.32 mm). Daily subconjunctival injection of pirenzepine was significantly less effective in preventing form deprivation myopia. Form deprivation myopia could still be induced in animals which had undergone pirenzepine treatment. Pirenzepine was effective in preventing the axial elongation associated with experimental myopia in a dose dependent manner and via a functional not toxic mechanism.
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Affiliation(s)
- E M Leech
- Department of Optometry and Vision Sciences, University of Wales, College of Cardiff, UK
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McBrien NA, Moghaddam HO, Cottriall CL, Leech EM, Cornell LM. The effects of blockade of retinal cell action potentials on ocular growth, emmetropization and form deprivation myopia in young chicks. Vision Res 1995; 35:1141-52. [PMID: 7610575 DOI: 10.1016/0042-6989(94)00237-g] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To investigate the influence of brain mediated functions on control of ocular growth, young chicks were treated monocularly with intravitreally injected tetrodotoxin (TTX) to block retinal ganglion cell action potentials. TTX injections (0.7 micrograms in 7 microliters) were given on day 6 after hatching in both binocularly open and monocularly deprived chicks. Injections were repeated every 48 hr for a period of 8 days (TTX-open; TTX-MD). Control groups of animals received intravitreally injected phosphate buffered saline (PBS-open; PBS-MD) to one eye on the same schedule. There was a minimum of eight animals in each group. Recovery from form-deprivation myopia during blockade of retinal cell action potentials was also investigated. Results demonstrate that blockade of retinal cell action potentials by TTX produces reduced growth of the anterior segment of the eye and crystalline lens in both binocularly open and MD chicks. Blockade of retinal cell action potentials does not prevent form-deprivation induced vitreous chamber elongation and myopia. Form deprived myopic eyes were found to emmetropize despite blockade of retinal ganglion cell action potentials giving further evidence for local ocular control of emmetropization. Blockade of retinal ganglion cell action potentials did not prevent changes in choroidal thickness in eyes developing axial myopia or eyes recovering from induced myopia.
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Affiliation(s)
- N A McBrien
- Department of Optometry and Vision Sciences, University of Wales, College of Cardiff
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