1
|
Nagae Y, Kuniyoshi K, Ishibashi M, Tanabe F, Matsumoto C, Kusaka S. Fundus autofluorescence, optical coherence tomography and electroretinography abnormalities in a patient with digoxin retinopathy that resemble those in KCNV2-associated retinopathy. Doc Ophthalmol 2023; 147:131-137. [PMID: 37460904 DOI: 10.1007/s10633-023-09942-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/21/2023] [Indexed: 07/23/2023]
Abstract
BACKGROUND Digoxin related retinal toxicity causes blurred vision, photophobia, central scotoma, color vision abnormality, and electroretinography (ERG) abnormalities. Here, we report a case with transient abnormalities in vison, in which fundus autofluorescence (FAF), optical coherence tomography (OCT), and ERG findings resembled those in KCNV2 (potassium voltage-gated channel modifier subfamily V member 2)-associated retinopathy. CASE REPORT An 89-year-old woman presented with complaints of acute blurred vision, nyctalopia, photophobia, and color vision abnormality. She received digoxin for tachycardia induced by atrial fibrillation for a month. The fundi showed a faint white ring at the fovea, which showed hyperfluorescence in FAF. OCT showed a thickened EZ in the macula. A dark-adapted (DA)-30 ERG showed a reduced and "squaring (trough-flattened)" a-wave, and a delayed, supernormal b-wave, resulting in a high b/a-wave amplitude ratio. The digoxin dose was reduced following an elevation in serum levels. Five weeks later, her visual acuities improved, and abnormal hyperfluorescence on FAF disappeared. After 6 months, no visual symptoms were reported. The ellipsoid-zone thickening in OCT improved; however, the b/a-wave amplitude ratio on DA-30 ERG remained high. The b-wave in LA-long-flash ERG was initially reduced, which improved after correction of serum level of digoxin. CONCLUSIONS The patient's clinical findings resembled those of patients with KCNV2-associated retinopathy or temporal hyperkalemia. These disorders appear to have a common pathogenesis, which may be related to abnormal extracellular potassium levels in the retina. The on-bipolar cells seemed to be more affected than the off-bipolar cells in digoxin related retinal toxicity.
Collapse
Affiliation(s)
- Yuki Nagae
- Department of Ophthalmology, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama City, Osaka, 589-8511, Japan
| | - Kazuki Kuniyoshi
- Department of Ophthalmology, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama City, Osaka, 589-8511, Japan.
| | - Marika Ishibashi
- Department of Ophthalmology, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama City, Osaka, 589-8511, Japan
| | - Fumi Tanabe
- Department of Ophthalmology, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama City, Osaka, 589-8511, Japan
| | - Chota Matsumoto
- Department of Ophthalmology, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama City, Osaka, 589-8511, Japan
| | - Shunji Kusaka
- Department of Ophthalmology, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama City, Osaka, 589-8511, Japan
| |
Collapse
|
2
|
Kim AH, Kolesnikova M, Ngo WK, Tsang SH. Effects of medications on hypoxia-inducible factor in the retina: A review. Clin Exp Ophthalmol 2023; 51:205-216. [PMID: 36594241 DOI: 10.1111/ceo.14161] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 08/22/2022] [Accepted: 08/26/2022] [Indexed: 01/04/2023]
Abstract
Hypoxia-inducible factor (HIF) plays a critical role in the mechanisms that allow cells to adapt to various oxygen levels in the environment. Specifically, HIF-1⍺ has shown to be widely involved in cellular repair, survival, and energy metabolism. HIF-1⍺ has also been found in increased levels in cancer cells, highlighting the importance of balance in the hypoxic response. Promoting HIF-1⍺ activity as a potential therapy for degenerative diseases and inhibiting HIF-1⍺ as a therapy for pathologies with overactive cell proliferation are actively being explored. Digoxin and metformin, HIF-1⍺ inhibitors, and deferoxamine and ⍺-ketoglutarate analogues, HIF-1⍺ activators, are being studied for application in age-related macular degeneration, diabetic retinopathy, and retinitis pigmentosa. However, these same medications have retinal toxicities that must be assessed before implementation of therapeutic care. Herein, we highlight the duality of therapeutic and toxic potential of HIF-1⍺ that must be carefully assessed prior to its clinical application in retinal disorders.
Collapse
Affiliation(s)
- Angela H Kim
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, New York-Presbyterian Hospital, New York, New York, USA.,Edward S. Harkness Eye Institute, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, New York, USA.,SUNY Downstate Medical School, Brooklyn, New York, USA
| | - Masha Kolesnikova
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, New York-Presbyterian Hospital, New York, New York, USA.,Edward S. Harkness Eye Institute, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, New York, USA.,SUNY Downstate Medical School, Brooklyn, New York, USA
| | - Wei Kiong Ngo
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, New York-Presbyterian Hospital, New York, New York, USA.,Edward S. Harkness Eye Institute, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, New York, USA.,National Healthcare Group Eye Institute, Tan Tock Seng Hospital, Singapore, Singapore
| | - Stephen H Tsang
- Jonas Children's Vision Care and Bernard & Shirlee Brown Glaucoma Laboratory, New York-Presbyterian Hospital, New York, New York, USA.,Edward S. Harkness Eye Institute, Columbia University Irving Medical Center/New York-Presbyterian Hospital, New York, New York, USA.,Departments of Pathology & Cell Biology, Columbia Stem Cell Initiative, New York, New York, USA.,Vagelos College of Physicians and Surgeons, Columbia University Irving Medical Center, New York, New York, USA
| |
Collapse
|
3
|
Dorgau B, Georgiou M, Chaudhary A, Moya-Molina M, Collin J, Queen R, Hilgen G, Davey T, Hewitt P, Schmitt M, Kustermann S, Pognan F, Steel DH, Sernagor E, Armstrong L, Lako M. Human Retinal Organoids Provide a Suitable Tool for Toxicological Investigations: A Comprehensive Validation Using Drugs and Compounds Affecting the Retina. Stem Cells Transl Med 2022; 11:159-177. [PMID: 35298655 PMCID: PMC8929478 DOI: 10.1093/stcltm/szab010] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 10/13/2021] [Indexed: 12/04/2022] Open
Abstract
Retinal drug toxicity screening is essential for the development of safe treatment strategies for a large number of diseases. To this end, retinal organoids derived from human pluripotent stem cells (hPSCs) provide a suitable screening platform due to their similarity to the human retina and the ease of generation in large-scale formats. In this study, two hPSC cell lines were differentiated to retinal organoids, which comprised all key retinal cell types in multiple nuclear and synaptic layers. Single-cell RNA-Seq of retinal organoids indicated the maintenance of retinal ganglion cells and development of bipolar cells: both cell types segregated into several subtypes. Ketorolac, digoxin, thioridazine, sildenafil, ethanol, and methanol were selected as key compounds to screen on retinal organoids because of their well-known retinal toxicity profile described in the literature. Exposure of the hPSC-derived retinal organoids to digoxin, thioridazine, and sildenafil resulted in photoreceptor cell death, while digoxin and thioridazine additionally affected all other cell types, including Müller glia cells. All drug treatments caused activation of astrocytes, indicated by dendrites sprouting into neuroepithelium. The ability to respond to light was preserved in organoids although the number of responsive retinal ganglion cells decreased after drug exposure. These data indicate similar drug effects in organoids to those reported in in vivo models and/or in humans, thus providing the first robust experimental evidence of their suitability for toxicological studies.
Collapse
Affiliation(s)
- Birthe Dorgau
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
- Newcells Biotech, Biosphere, Newcastle Helix, Newcastle upon Tyne, UK
| | - Maria Georgiou
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
| | - Alexander Chaudhary
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
| | - Marina Moya-Molina
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
- Newcells Biotech, Biosphere, Newcastle Helix, Newcastle upon Tyne, UK
| | - Joseph Collin
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
| | - Rachel Queen
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
| | - Gerrit Hilgen
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
- Northumbria University, Applied Sciences, Faculty of Health and Life Science, Newcastle upon Tyne, UK
| | - Tracey Davey
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
- Electron Microscopy Research Services, Newcastle University, Newcastle upon Tyne, UK
| | | | | | - Stefan Kustermann
- Pharmaceutical Sciences, F. Hoffmann-La Roche, Pharma Research and Early Development, Roche Innovation Center Basel, Switzerland
| | | | - David H Steel
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
| | - Evelyne Sernagor
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
| | - Lyle Armstrong
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
- Newcells Biotech, Biosphere, Newcastle Helix, Newcastle upon Tyne, UK
| | - Majlinda Lako
- Newcastle University, Biosciences Institute, Faculty of Medical Sciences, Newcastle upon Tyne, UK
| |
Collapse
|
4
|
Schmid V, Plössl K, Schmid C, Bernklau S, Weber BHF, Friedrich U. Retinoschisin and Cardiac Glycoside Crosstalk at the Retinal Na/K-ATPase. Invest Ophthalmol Vis Sci 2020; 61:1. [PMID: 32392309 PMCID: PMC7405613 DOI: 10.1167/iovs.61.5.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Purpose Mutations in the RS1 gene, which encodes retinoschisin, cause X-linked juvenile retinoschisis, a retinal dystrophy in males. Retinoschisin specifically interacts with the retinal sodium–potassium adenosine triphosphatase (Na/K-ATPase), a transmembrane ion pump. Na/K-ATPases also bind cardiac glycosides, which control the activity of the pump and have been linked to disturbances in retinal homeostasis. In this study, we investigated the crosstalk between retinoschisin and cardiac glycosides at the retinal Na/K-ATPase and the consequences of this interplay on retinal integrity. Methods The effect of cardiac glycosides (ouabain and digoxin) on the binding of retinoschisin to the retinal Na/K-ATPase was investigated via western blot and immunocytochemistry. Also, the influence of retinoschisin on the binding of cardiac glycosides was analyzed via enzymatic assays, which quantified cardiac glycoside-sensitive Na/K-ATPase pump activity. Moreover, retinoschisin-dependent binding of tritium-labeled ouabain to the Na/K-ATPase was determined. Finally, a reciprocal effect of retinoschisin and cardiac glycosides on Na/K-ATPase localization and photoreceptor degeneration was addressed using immunohistochemistry in retinoschisin-deficient murine retinal explants. Results Cardiac glycosides displaced retinoschisin from the retinal Na/K-ATPase; however, retinoschisin did not affect cardiac glycoside binding. Notably, cardiac glycosides reduced the capacity of retinoschisin to regulate Na/K-ATPase localization and to protect against photoreceptor degeneration. Conclusions Our findings reveal opposing effects of retinoschisin and cardiac glycosides on retinal Na/K-ATPase binding and on retinal integrity, suggesting that a fine-tuned interplay between both components is required to maintain retinal homeostasis. This observation provides new insight into the mechanisms underlying the pathological effects of cardiac glycoside treatment on retinal integrity.
Collapse
|
5
|
Shi L, Sun LD, Odel JG. Colored floaters as a manifestation of digoxin toxicity. Am J Ophthalmol Case Rep 2018; 10:233-235. [PMID: 29780940 PMCID: PMC5956671 DOI: 10.1016/j.ajoc.2018.02.024] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 11/24/2017] [Accepted: 02/26/2018] [Indexed: 11/17/2022] Open
Abstract
PURPOSE Since its report in one patient more than 70 years ago, digitalis-induced colored muscae volitantes have not surfaced again in the literature. We report here a case of digoxin induced colored floaters. OBSERVATIONS An 89-year-old man on 0.25 mg digoxin daily developed visual hallucinations and colored floaters. He had floaters in the past but now they were in various colors including yellow, green, blue and red, though predominantly in yellow. These "weirdly" shaped little particles wiggled around as if in a viscous solution and casted shadows in his vision. He also saw geometric shapes, spirals, and cross hatch patterns of various colors that moved and undulated, especially on wallpaper. Ophthalmic examination revealed reduced visual acuity, poor color vision especially in his left eye, along with central depression on Amsler grid and Humphrey visual field in his left eye. Discontinuation of digoxin resulted in complete resolution of his visual symptoms. On subsequent ophthalmic examination, the patient's visual acuity, field testing and color vision improved and he had normal Amsler grid test results. CONCLUSIONS AND IMPORTANCE Colored floaters may occur in patients taking cardiac glycosides but this association has not been explored. Unlike optical illusions and visual hallucinations, floaters are entoptic phenomena casting a physical shadow upon the retina and their coloring likely arise from retinal dysfunction. Colored floaters may be a more common visual phenomenon than realized.
Collapse
Affiliation(s)
- Lynn Shi
- College of Physicians and Surgeons, Columbia University Medical Center, New York, N.Y., United States
- Department of Ophthalmology, Columbia University Medical Center, New York, N.Y., United States
| | - Linus D. Sun
- Department of Ophthalmology, Columbia University Medical Center, New York, N.Y., United States
| | - Jeffrey G. Odel
- Department of Ophthalmology, Columbia University Medical Center, New York, N.Y., United States
| |
Collapse
|
6
|
Hinshaw SJH, Ogbeifun O, Wandu WS, Lyu C, Shi G, Li Y, Qian H, Gery I. Digoxin Inhibits Induction of Experimental Autoimmune Uveitis in Mice, but Causes Severe Retinal Degeneration. Invest Ophthalmol Vis Sci 2016; 57:1441-7. [PMID: 27028065 PMCID: PMC4821074 DOI: 10.1167/iovs.15-19040] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Accepted: 02/24/2016] [Indexed: 02/06/2023] Open
Abstract
PURPOSE Digoxin, a major medication for heart disease, was recently reported to have immunosuppressive capacity. Here, we determined the immunosuppressive capacity of digoxin on the development of experimental autoimmune uveitis (EAU) and on related immune responses. METHODS The B10.A mice were immunized with interphotoreceptor retinoid-binding protein (IRBP) and were treated daily with digoxin or vehicle control. On postimmunization day 14, the mouse eyes were examined histologically, while spleen cells were tested for cytokine production in response to IRBP and purified protein derivative. The immunosuppressive activity of digoxin was also tested in vitro, by its capacity to inhibit development of Th1 or Th17 cells. To investigate the degenerative effect of digoxin on the retina, naïve (FVB/N × B10.BR)F1 mice were similarly treated with digoxin and tested histologically and by ERG. RESULTS Treatment with digoxin inhibited the development of EAU, as well as the cellular response to IRBP. Unexpectedly, treatment with digoxin suppressed the production of interferon-γ to a larger extent than the production of interleukin 17. Importantly, digoxin treatment induced severe retinal degeneration, determined by histologic analysis with thinning across all layers of the retina. Digoxin treatment also induced dose-dependent vision loss monitored by ERG on naïve mice without induction of EAU. CONCLUSIONS Treatment of mice with digoxin inhibited the development of EAU and cellular immune response to IRBP. However, the treatment induced severe damage to the retina. Thus, the use of digoxin in humans should be avoided due to its toxicity to the retina.
Collapse
Affiliation(s)
- Samuel J. H. Hinshaw
- Laboratory of Immunology National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Osato Ogbeifun
- Laboratory of Immunology National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Wambui S. Wandu
- Laboratory of Immunology National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Cancan Lyu
- Laboratory of Immunology National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Guangpu Shi
- Laboratory of Immunology National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Yichao Li
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Haohua Qian
- Visual Function Core, National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| | - Igal Gery
- Laboratory of Immunology National Eye Institute, National Institutes of Health, Bethesda, Maryland, United States
| |
Collapse
|
7
|
Meletiadis J, Chanock S, Walsh TJ. Defining targets for investigating the pharmacogenomics of adverse drug reactions to antifungal agents. Pharmacogenomics 2008; 9:561-84. [DOI: 10.2217/14622416.9.5.561] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Adverse drug reactions (ADRs) associated with antifungal therapy are major problems in patients with invasive fungal infections. Whether by clinical history or patterns of genetic variation, the identification of patients at risk for ADRs should result in improved outcomes while minimizing deleterious side effects. A major contributing factor to ADRs with antifungal agents relates to drug distribution, metabolism and excretion. Genetic variation in key genes can alter the structure and expression of genes and gene products (e.g., proteins). Thus far, the effort has focused on identifying polymorphisms with either empirical or predicted in silico functional consequences; the best candidate genes encode phase I and II drug-metabolizing enzymes (e.g., CYP2C19 and N-acetyltransferase), plasma proteins (albumin and lipoproteins) and drug transporters (P-glycoprotein and multidrug resistance proteins), which can affect the disposition of antifungal agents, eventually leading to dose-dependent (type A) toxicity. Less is known regarding the key genes that interact with antifungal agents, resulting in idiosyncratic (type B) ADRs. The possible role of certain gene products and genetic polymorphisms in the toxicities of antifungal agents are discussed in this review. The preliminary data address the following: low-density lipoproteins and cholesteryl ester transfer protein in amphotericin B renal toxicity; toll-like receptor 1 and 2 in amphotericin B infusion-related ADRs; phosphodiesterase 6 in voriconazole visual adverse events; flavin-containing monooxygenase, glutathione transferases and multidrug resistance proteins 1 and 2 in ketoconazole and terbinafine hepatotoxicity; CYP enzymes and P-glycoprotein in drug interactions between azoles and coadministered medications; multidrug resistance proteins 8 and 9 on 5-flucytosine bone marrow toxicity; and mast cell activation in caspofungin histamine release. This will focus on high-priority candidate genes, which could provide a starting point for molecular studies to elucidate the potential mechanisms for understanding toxicity associated with antifungal drugs as well as identifying candidate genes for large population prospective genetic association studies.
Collapse
Affiliation(s)
- Joseph Meletiadis
- National Cancer Institute, National Institutes of Health, Pediatric Oncology Branch, Bethesda, MD 20814, USA
- Attikon University General Hospital, Laboratoty for Clinical Microbiology, 1 Rimini Street, Athens 124 62, Greece
| | - Stephen Chanock
- National Cancer Institute, National Institutes of Health, Pediatric Oncology Branch, Bethesda, MD 20814, USA
| | - Thomas J Walsh
- National Cancer Institute, National Institutes of Health, Pediatric Oncology Branch, Bethesda, MD 20814, USA
| |
Collapse
|
8
|
Sato S. [Evaluation of ophthalmic toxicity]. Nihon Yakurigaku Zasshi 2008; 131:50-54. [PMID: 18187885 DOI: 10.1254/fpj.131.50] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
|
9
|
Ishimaru T, Yokogawa H. Olfactory and gustatory disturbances caused by digitalism: A case report. Auris Nasus Larynx 2006; 33:465-9. [PMID: 16730151 DOI: 10.1016/j.anl.2006.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Revised: 02/07/2006] [Accepted: 03/17/2006] [Indexed: 11/17/2022]
Abstract
It is known that an overdose of digoxin causes visual disturbance, but the effect on the senses of smell and taste is not known. A case of olfactory and gustatory disturbance caused by digitalism is reported. In a 62-year-old male patient suffering from chronic digitalism, the serum digoxin level rose to 6.0 ng/ml. The patient was diagnosed not only with visual disturbance but also hyposmia and hypogeusia. The patient recovered from visual and chemosensory disturbances after the serum digoxin concentration returned to normal. Because the similarity of intracellular signal transduction between photoreceptor cells and olfactory and/or taste receptor cells is known, it is suspected that the influence of digoxin to chemosensory organs was caused by intermediation of sodium-potassium-adenosine triphosphatase (Na-K-ATPase) of the chemosensory receptor cells.
Collapse
Affiliation(s)
- Tadashi Ishimaru
- Department of Otolaryngology, Nanto General Hospital, 2007-5 Umeno, Nanto, Toyama, Japan.
| | | |
Collapse
|
10
|
Abstract
CASE REPORT To present a case of photopsia resulting from digoxin intoxication brought about by dehydration in a 72-year-old woman. COMMENTS Ophthalmologists may be the first clinicians to notice the symptoms of digitalis intoxication, which is potentially a life-threatening condition.
Collapse
Affiliation(s)
- Akio Oishi
- Department of Ophthalmology and Visual Sciences, Kyoto University Graduate School of Medicine, Japan.
| | | | | | | |
Collapse
|
11
|
Maehara S, Osawa A, Itoh N, Wakaiki S, Tsuzuki K, Seno T, Kushiro T, Yamashita K, Izumisawa Y, Kotani T. Detection of cone dysfunction induced by digoxin in dogs by multicolor electroretinography. Vet Ophthalmol 2005; 8:407-13. [PMID: 16359364 DOI: 10.1111/j.1463-5224.2005.00415.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is difficult to detect discrete cone function with the present conventional electroretinography (ERG) examination. In this study, we developed contact electrodes with a built-in color (red (644 nm), green (525 nm), or blue (470 nm)) light source (color LED-electrode), and evaluated an experimental model of digoxin in the dog. First, 17 normal Beagle dogs were used to determine which electrode works well for color ERG measurement on dogs. Then, color ERG was performed on seven normal Beagle dogs at various points during a 14-day period of digoxin administration. A single daily dose of 0.0125 mg/kg/day, which is within the recommended oral maintenance dosage range for dogs, was administered orally for 2 weeks. Ophthalmic examination, measurement of plasma concentration of digoxin, and color ERG examination were performed. On first examination, amplitudes of all responses were significantly (P < 0.01) lower with the red, than with the blue and green electrodes during ERG recording. In ERG using the red electrode, the standard deviation was large. According to these preliminary results, the red electrode was not used in the experimental dog model with digoxin. In the digoxin administrated animals, no significant change was observed in the ophthalmic examination findings. The digoxin level increased steadily throughout the dosing period but was always within the therapeutic range for dogs. In rod ERG, no abnormalities were detected with any electrode. In standard combined ERG, decreased amplitude of the a-wave was detected with every electrode. In single flash cone ERG, prolongation of implicit time was detected by color ERG with the blue and green electrodes. In 30-Hz flicker ERG, decreased amplitude was detected only by color ERG with the blue electrode. The decreased amplitude and prolonged implicit time recovered after termination of digoxin administration. Cone dysfunction induced by digoxin in the dog was revealed by multicolor ERG using blue and green LED-electrodes. Multi-color ERG was useful for detecting cone type-specific dysfunction in the dog.
Collapse
Affiliation(s)
- Seiya Maehara
- Department of Companion Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501, Japan.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Lawrenson JG, Kelly C, Lawrenson AL, Birch J. Acquired colour vision deficiency in patients receiving digoxin maintenance therapy. Br J Ophthalmol 2002; 86:1259-61. [PMID: 12386084 PMCID: PMC1771354 DOI: 10.1136/bjo.86.11.1259] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
BACKGROUND/AIMS Disturbances of colour vision are a frequently reported sign of digoxin toxicity. The aim of this study was to investigate the incidence of acquired colour vision deficiency in elderly hospitalised patients receiving maintenance digoxin therapy. METHODS 30 patients (mean age 81.3 (SD 6.1) years) receiving digoxin were tested using a battery of colour vision tests (Ishihara, AO Hardy Rand Rittler plates, City tritan test, Lanthony tritan album, and the Farnsworth D15). These were compared to an age matched control group. Serum digoxin concentrations were determined from venous blood samples. RESULTS Slight to moderate red-green impairment was found in approximately 20-30% of patients taking digitalis, and approximately 20% showed a severe tritan deficiency. There was no correlation between colour vision impairment and serum digoxin level. CONCLUSIONS Formal colour vision testing of elderly patients taking digitalis showed a high incidence of colour deficiency, suggesting that impairment of retinal function can occur even at therapeutic drug levels. As a result, colour vision testing in this population would have limited value for the detection of drug toxicity.
Collapse
Affiliation(s)
- J G Lawrenson
- Applied Vision Research Centre, Department of Optometry and Visual Science, City University, London EC1V 0HB, UK.
| | | | | | | |
Collapse
|
13
|
Grisaru D, Sternfeld M, Eldor A, Glick D, Soreq H. Structural roles of acetylcholinesterase variants in biology and pathology. EUROPEAN JOURNAL OF BIOCHEMISTRY 1999; 264:672-86. [PMID: 10491113 DOI: 10.1046/j.1432-1327.1999.00693.x] [Citation(s) in RCA: 268] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Apart from its catalytic function in hydrolyzing acetylcholine, acetylcholinesterase (AChE) affects cell proliferation, differentiation and responses to various insults, including stress. These responses are at least in part specific to the three C-terminal variants of AChE which are produced by alternative splicing of the single ACHE gene. 'Synaptic' AChE-S constitutes the principal multimeric enzyme in brain and muscle; soluble, monomeric 'readthrough' AChE-R appears in embryonic and tumor cells and is induced under psychological, chemical and physical stress; and glypiated dimers of erythrocytic AChE-E associate with red blood cell membranes. We postulate that the homology of AChE to the cell adhesion proteins, gliotactin, glutactin and the neurexins, which have more established functions in nervous system development, is the basis of its morphogenic functions. Competition between AChE variants and their homologs on interactions with the corresponding protein partners would inevitably modify cellular signaling. This can explain why AChE-S exerts process extension from cultured amphibian, avian and mammalian glia and neurons in a manner that is C-terminus-dependent, refractory to several active site inhibitors and, in certain cases, redundant to the function of AChE-like proteins. Structural functions of AChE variants can explain their proliferative and developmental roles in blood, bone, retinal and neuronal cells. Moreover, the association of AChE excess with amyloid plaques in the degenerating human brain and with progressive cognitive and neuromotor deficiencies observed in AChE-transgenic animal models most likely reflects the combined contributions of catalytic and structural roles.
Collapse
Affiliation(s)
- D Grisaru
- Department of Biological Chemistry, The Institute of Life Sciences, The Hebrew University, Jerusalem, 91904 Israel
| | | | | | | | | |
Collapse
|
14
|
Broide RS, Grifman M, Loewenstein A, Grisaru D, Timberg R, Stone J, Shani M, Patrick JW, Soreq H. Manipulations of ACHE gene expression suggest non-catalytic involvement of acetylcholinesterase in the functioning of mammalian photoreceptors but not in retinal degeneration. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1999; 71:137-48. [PMID: 10521568 DOI: 10.1016/s0169-328x(99)00169-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To explore role(s) of acetylcholinesterase (AChE) in functioning and diseased photoreceptors, we studied normal (rd/+) and degenerating (rd/rd) murine retinas. All retinal neurons, expressed AChEmRNA throughout fetal development. AChE and c-Fos mRNAs peaked at post-natal days 10-12, when apoptosis of rd/rd photoreceptors begins. Moreover, c-Fos and AChEmRNA were co-overexpressed in rd/rd mice producing transgenic human (h), and host (m) AChE, but not in rd/+ mice. However, mAChE overexpression also occurred in transgenics expressing human serum albumin. Drastic variations in AChE catalytic activity were ineffective during development. Neither transgenic excess nor diisopropylfluorophosphonate (DFP) inhibition (80%) affected the rd phenotype; nor did DFP exposure induce photoreceptor degeneration or affect other key cholinergic proteins in rd/+ mice, unlike reports of adult mice and despite massive induction under DFP of c-Fos70 years). Therefore, the extreme retinal sensitivity to AChE modulation may reflect non-catalytic function(s) of AChE in adult photoreceptors. These findings exclude AChE as causing the rd phenotype, suggest that its primary function(s) in mammalian retinal development are non-catalytic ones and indicate special role(s) for the AChE protein in adult photoreceptors.
Collapse
Affiliation(s)
- R S Broide
- Department of Biological Chemistry, Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | | | | | | | | | | | | | | | | |
Collapse
|