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Hafezi F, Bijani M, Gholamrezai S, Savari M, Panzer-Krause S. Towards sustainable community-based ecotourism: A qualitative content analysis. Sci Total Environ 2023:164411. [PMID: 37245807 DOI: 10.1016/j.scitotenv.2023.164411] [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] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 05/11/2023] [Accepted: 05/21/2023] [Indexed: 05/30/2023]
Abstract
Community-based ecotourism (CBET) provides benefits to society members, especially concerning to the environment, by giving them the opportunity to influence and participate in the development of tourism. Lorestan province in the west of Iran is influenced by this phenomenon by having specific CBET opportunities in different economic, social, environmental and physical dimensions. The purpose of this study was to develop a sustainable community-based ecotourism (SCBET) model using the qualitative content analysis (with a deductive method in the form of the Hartmut model). The documents used included a systematic study of 45 international articles, 12 local articles, 2 books and in-depth interviews with 11 local experts. The results showed that the crystallization of CBET can be formed in the form of a four-component model (including planning, implementation, evaluation and situation analysis). In this model, four stages of the process of implementing community-based tourism (CBT) have been presented, in all of which the participation of researchers, ecotourists, policymakers and local people have been of great importance. Finally, the extracted categories for CBET sustainability were matched with the standards of the Global Sustainable Tourism Council (GSTC) (including sustainable management, cultural sustainability, socio-economic sustainability and environmental sustainability) and the final SCBET model was presented. This model can be useful for policy makers for decision-making and planning in the SCBET field.
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Affiliation(s)
- Fereshteh Hafezi
- Department of Agricultural Extension and Education, College of Agriculture, Tarbiat Modares University (TMU), Tehran, Iran.
| | - Masoud Bijani
- Department of Agricultural Extension and Education, College of Agriculture, Tarbiat Modares University (TMU), Tehran, Iran.
| | - Saeed Gholamrezai
- Department of Agricultural Economics and Rural Development, College of Agriculture, Lorestan University (LU), Lorestan, Iran.
| | - Moslem Savari
- Department of Agricultural Extension and Education, Khuzestan University of Agricultural Sciences and Natural Resources, Mollasani, Iran.
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Panos GD, Panos LD, Hafezi F, Gatzioufas Z. Ischemic optic neuropathy after a long airplane flight: coincidence or rare economy class syndrome manifestation? Klin Monbl Augenheilkd 2014; 231:390-1. [PMID: 24771175 DOI: 10.1055/s-0034-1368250] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- G D Panos
- Department of Ophthalmology, Geneva University Hospitals, Switzerland (Chairman: Professor Dr. Dr. Farhad Hafezi)
| | - L D Panos
- Department of Neurology, Darmstadt Hospital, University of Heidelberg-Mannheim (Chairman: Prof. Dr. med. Rainer Kollmar)
| | - F Hafezi
- Department of Ophthalmology, Geneva University Hospitals, Switzerland (Chairman: Professor Dr. Dr. Farhad Hafezi)
| | - Z Gatzioufas
- Department of Ophthalmology, Geneva University Hospitals, Switzerland (Chairman: Professor Dr. Dr. Farhad Hafezi)
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3
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Quenan S, Strueven V, Saxer N, Laffitte E, Kaya G, Krischer J, Hafezi F, Le Gal FA. Pruritic acquired nevus of Ota. Dermatology 2013; 227:186-8. [PMID: 24060704 DOI: 10.1159/000354604] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Accepted: 07/17/2013] [Indexed: 11/19/2022] Open
Abstract
Nevus of Ota is a unilateral, asymptomatic cutaneous and mucosal hyperpigmentation of the face that is congenital or may appear during childhood. We present a case of symptomatic acquired nevus of Ota in an adult, associated with intense pruritus, not described in the literature so far. A 32-year-old woman presented with brownish mottled macules which appeared on her face progressively over 8 days, following the distribution of the first and second divisions of the left trigeminal nerve and partially covering the iris and sclera of the left eye. She reported an intense pruritus in this area. We performed a biopsy on the left forehead, which confirmed the diagnosis of nevus of Ota. Specific stains and immunohistochemistry revealed increased numbers of mast cells. Ophthalmological tests showed acute acquired melanocytosis of the left iris and sclera. The origin of the nevus is still unclear. Several hypotheses suggest a reactivation of melanocytes during their migration from the neural crest. The pruritus reported in our patient may be explained by the increased quantity of mast cells observed in the lesion and/or neuronal stimulation of the ophthalmic and maxillary divisions of the fifth cranial nerve.
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Affiliation(s)
- S Quenan
- Department of Dermatology, Geneva University Hospitals, Geneva, Switzerland
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Gatzioufas Z, Hafezi F, Kopsidas K, Thanos S. Dysfunctional uveoscleral pathway in a rat model of congenital glaucoma. J Physiol Pharmacol 2013; 64:393-397. [PMID: 23959737] [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] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Accepted: 06/10/2013] [Indexed: 06/02/2023]
Abstract
UNLABELLED The purpose of the study was to investigate the presence of the uveoscleral pathway in the normotensive rat (NR) and in a rat model of congenital glaucoma (CGR). We injected the fluorescent tracer 70-kDa dextran rhodamine B in the anterior chamber of four NRs and four CGRs. At 10 and 60 minutes after injection, rats were euthanized by CO₂ inhalation and eyes were enucleated. Cryosections were prepared and analyzed using fluorescent microscopy. Hematoxylin-eosin staining and electron microscopy of the anterior chamber angle (ACA) were performed. At 10 minutes after injection, fluorescent tracer was detected in the iris root and ciliary processes of NRs and CGRs. At 60 minutes, NRs showed prominent signal in the suprachoroidal, whereas, in the CGRs, tracer was barely detectable. Histology of the anterior chamber revealed the presence of an open ACA and electron microscopy confirmed the normal structure of the ciliary body in CGRs. CONCLUSIONS Our results document the presence of an uveoscleral pathway in the normotensive rat. The rat model of congenital glaucoma shows severe impairment of the uveoscleral pathway, suggesting that alterations of the uveoscleral outflow might play a role in the pathogenesis of CG.
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Affiliation(s)
- Z Gatzioufas
- Department of Ophthalmology, University Hospitals of Geneva HUG, Geneva, Switzerland.
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Tschuor P, Hafezi F, Majo F. Iris varix as a cause of late-onset inflammation after implantation of a phakic iris claw lens. Klin Monbl Augenheilkd 2012; 229:462-3. [PMID: 22496033 DOI: 10.1055/s-0031-1299255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- P Tschuor
- Jules-Gonin Eye Hospital, University of Lausanne, Switzerland
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Hafezi F, Koller T, Vinciguerra P, Seiler T. Marked remodelling of the anterior corneal surface following collagen cross-linking with riboflavin and UVA. Br J Ophthalmol 2010; 95:1171-2. [DOI: 10.1136/bjo.2010.184978] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Hafezi F, Dejica P, Majo F. Modified corneal collagen crosslinking reduces corneal oedema and diurnal visual fluctuations in Fuchs dystrophy. Br J Ophthalmol 2010; 94:660-1. [DOI: 10.1136/bjo.2009.162479] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Bertschinger D, Hashemi K, Hafezi F, Majo F. Infections after PRK Could Have a Happy Ending: A Series of Three Cases. Klin Monbl Augenheilkd 2010; 227:315-8. [DOI: 10.1055/s-0029-1245222] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Hafezi F, Moesen I, Carels G, Mooy C, Paridaens D. [Waldenstrom's macroglobulinaemia of the lacrimal gland in a patient with sarcoidosis]. Ophthalmologe 2010; 107:60-3. [PMID: 19669149 DOI: 10.1007/s00347-009-2010-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
We report a case of bilateral lacrimal gland involvement as the first sign of Waldenstrom's macroglobulinaemia in a patient with sarcoidosis. Histological analysis of an incisional biopsy revealed a lymphoplasmocytic lymphoma consistent with Waldenstrom's macroglobulinaemia. No noncaseating granulomas were encountered. Systemic treatment was initiated and resulted in complete resolution of the lesions. In a patient with a systemic disease, such as sarcoidosis, and lacrimal gland involvement, a biopsy of the lacrimal gland mass should be taken to make a correct diagnosis and start appropriate treatment.
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Affiliation(s)
- F Hafezi
- IROC, Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Schweiz
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Berguiga M, Uffer S, Hafezi F, Majo F. Pseudomonas cepacia (PC) contamination of a cornea conservated in organ culture. Klin Monbl Augenheilkd 2009; 226:348-9. [PMID: 19384798 DOI: 10.1055/s-0028-1109284] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- M Berguiga
- Hôpital Ophtalmique Jules-Gonin, Faculté de Médecine de Lausanne, Switzerland
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11
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Lindstedt E, Hafezi F, Veckeneer M, Mooy C, Paridaens D. Orbitale Entzündung bei intraokularem malignen Melanom. Klin Monbl Augenheilkd 2008; 225:888-9. [DOI: 10.1055/s-2008-1027719] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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12
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Moesen I, Hafezi F, Paridaens D. [Corneal dellen secondary to conjunctival chemosis following transconjunctival orbital decompression]. Klin Monbl Augenheilkd 2007; 224:856-7. [PMID: 18034401 DOI: 10.1055/s-2007-963618] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
BACKGROUND Transconjunctival orbital decompression ("swinging eyelid technique") nowadays is the technique of choice for the reduction of proptosis in Graves' orbitopathy. Here, we present the first report of two patients who developed corneal dellen secondary to conjunctival chemosis following swinging eyelid decompression. CASE REPORTS Two female patients, 38 and 52 years old, underwent transconjunctival orbital decompression in 2006. Postoperatively, they developped corneal dellen secondary to conjunctival chemosis. The dellen and the chemosis completely regressed after intensive topical and oral therapy. CONCLUSION Corneal dellen represent a potential cause of postoperative pain following transconjunctival orbital decompression.
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Affiliation(s)
- I Moesen
- Department of Oculoplastic & Orbital Surgery, The Rotterdam Eye Hospital, The Netherlands
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Affiliation(s)
- F Hafezi
- IROC, Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Switzerland
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Abstract
Adenoid cystic carcinoma (ACC) is a rare epithelial malignancy, which tends to grow slowly. ACC is an intractable neoplasm due to its ability to invade perineural spaces. Local recurrence after excision is not unusual. ACC most commonly arises in the lacrimal gland. Very rarely, ACC originates from accessory lacrimal gland tissue. Here, we present a patient with a large ACC of the central upper eyelid, which had been misdiagnosed and treated as a chalazion without histological examination. Its origin most likely is an accessory lacrimal gland.
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Affiliation(s)
- J C Paarlberg
- Department of Oculoplastic & Orbital Surgery, The Rotterdam Eye Hospital, Rotterdam, Niederlande
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Hafezi F, Iseli HP, Seiler T. Quervernetzung bei iatrogener Keratektasie nach LASIK. Klin Monbl Augenheilkd 2007. [DOI: 10.1055/s-2007-976205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Hafezi F, Bockholts D, van den Bosch WA, Paridaens ADA. [Giant mucocele of all paranasal sinuses with massive bilateral globe displacement]. Ophthalmologe 2006; 103:340-1. [PMID: 15995842 DOI: 10.1007/s00347-005-1246-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Although of benign nature and slowly progressive, paranasal sinus mucoceles may, depending on their localization, cause a multitude of ophthalmological symptoms due to compression and displacement of adjacent tissue. Here we report the unusual case of a patient suffering from a progressively growing giant mucocele that developed years after ENT surgery and that was neglected for almost 2 decades despite massive symptoms. This case report demonstrates the importance of including mucoceles of the paranasal sinuses into the differential diagnosis of unilateral or bilateral proptosis.
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Affiliation(s)
- F Hafezi
- IROC, Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Schweiz
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Abstract
BACKGROUND Nomograms are efficient tools to improve the predictability of refractive procedures by using statistical methods to analyze pre- and postoperative refractive data. The purpose of this work was to analyze the clinical relevance and limitations of nomograms in a case series. METHODS Computer simulations based on the known unpredictability for refractive outcomes were performed for three different distribution functions of the preoperative refractions. In addition, the clinical applicability was investigated in three different cohorts that underwent laser in situ keratomileusis (LASIK). RESULTS The use of individual nomograms significantly improves the predictability of the refractive outcome. However, theoretical investigation demonstrates that a homogeneous data distribution within cohorts is a key factor for predictable nomogram calculations. Outliers within the cohorts are not integrated into the nomogram calculation due to the mathematical model used. CONCLUSIONS Nomograms are helpful for improving refractive outcomes. However, they are currently limited to approximately 90% within +/-0.5 D.
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Affiliation(s)
- M Mrochen
- IROC AG, Institut für Refraktive und Ophthalmo-Chirurgie, Zürich, Schweiz
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Seiler T, Hafezi F, Iseli HP, Koller T, Alkara N. [Reoperations after LASIK]. Klin Monbl Augenheilkd 2006; 223:509-12. [PMID: 16804821 DOI: 10.1055/s-2005-859016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
BACKGROUND Repeat operations after refractive surgery have increased in frequency during the past 10 years. The spectrum of the indications for repeat LASIK may have changed. METHODS All cases of repeat operations after refractive surgery performed between May 1, 2004 and April 30, 2005 at the Institute of Refractive and Ophthalmic Surgery (IROC) were retrospectively investigated regarding indication for repeat surgery and visual and refractive results. The 1-month results were used to estimate the refractive and visual success rate. RESULTS Of the 76 reoperations, 69 were performed as re-lifts, 3 eyes had new lamellae cut, and 3 cases needed keratoplasties. The reoperations took place 7.5 +/- 13 months after the primary operation (range 0.5 to 60 months). The most frequent indication was residual astigmatism of 0.5 D and more. Visual loss of more than 1 decimal line did not occur and unaided visual acuity increased from 0.64 to 1.05. No complications were reported, however, 3 eyes needed additional enhancement. CONCLUSIONS Reoperations after LASIK performed as re-lifts appear to be effective and reasonably safe when using the technique described and respecting a residual stromal thickness of 280 microns.
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Affiliation(s)
- T Seiler
- Institut für Refraktive und Ophthalmo-Chirurgie (IROC), Zürich, Schweiz.
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Abstract
The predictability and quality of results in corneal refractive laser surgery are determined by a number of factors. Here, the calculation and choice of the ablation profile represent central elements. Our growing knowledge about the physical and optical properties of the eye in recent years has led to the development of different strategies in the generation of ablation profiles. This review describes the currently used ablation profiles with their advantages and disadvantages and provides an outlook on future methods for the calculation of ablation profiles.
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Affiliation(s)
- M Mrochen
- IROC, Institut für Refraktive und Ophthalmo-Chirurgie, Stockerstrasse 37, 8002 Zürich, Switzerland.
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Iseli HP, Bueeler M, Hafezi F, Seiler T, Mrochen M. Dependence of wave front refraction on pupil size due to the presence of higher order aberrations. Eur J Ophthalmol 2006; 15:680-7. [PMID: 16329051 DOI: 10.1177/112067210501500605] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [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: 11/16/2022]
Abstract
PURPOSE Propagation of light through the optical pathway within the eye can lead to a deformation of the wave front that might affect objective but also subjective refraction depending on pupil size. The aim of this study was to investigate the change in wave front refraction that is calculated on the basis of second order Zernike polynomials when varying the pupil size from 6 mm to 3 mm. The change was correlated with the amount of fourth and sixth order spherical aberration and fourth and sixth order astigmatism. METHODS Wave front aberrations were measured in 130 eyes by means of a Tscherning wave front sensor at a pupil size of 6 mm. Wave front aberrations in terms of Zernike coefficients up to sixth order were approximated for 6 mm and 3 mm pupil size. The wave front refraction was calculated based on the second order Zernike coefficients for both pupil diameters. Resulting differences in wave front refraction (sphere or cylinder) due to the change in pupil size were correlated with the initial higher order aberrations determined for the 6.0 mm pupil by means of a linear regression (Spearman rank correlation coefficient). RESULTS The correlation between the change in sphere and cylinder on one hand and the spherical aberration and higher order astigmatism on the other hand was found to be highly significant (p<0.001), with a correlation coefficient of R = 0.96 for sphere and R = 0.85 for cylinder. CONCLUSIONS Calculating the wave front refraction on the basis of second order Zernike polynomials is plagued with the influence of the higher order aberration preexisting in the individual eye. This is one reason why this method does not represent precisely enough subjective refraction. Other methods that calculate the refraction based on wave front measurement independent from the pupil size should be established in the ophthalmic community.
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Affiliation(s)
- H P Iseli
- IROC Institute of Refractive and Ophthalmic Surgery, Zurich, Switzerland.
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Abstract
PURPOSE In the past few years, the essential role of the homeobox gene Pax6 for eye development has been demonstrated unambiguously in a variety of species including humans. In humans, Pax6 mutations lead to a variety of ocular malformations of the anterior and posterior segment. However, little is known about PAX6 expression in the adult human retina. We have therefore investigated PAX6 levels and localization in the human retina at various ages. METHODS Adult human eyes of various ages (17-79 years) were obtained from the Zurich Eye Bank. PAX6 expression levels and patterns were analysed by Western blot analysis of total retinal protein and by immunohistochemistry on paraffin sections, respectively. RESULTS PAX6 expression in the retina was detected up to 79 years of donor age and was predominantly localized to the ganglion cell layer and the inner part of the inner nuclear layer. CONCLUSIONS PAX6 remains distinctly expressed throughout the lifespan of the human retina suggesting a role for PAX6 in the retina after completion of eye morphogenesis.
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Affiliation(s)
- D Stanescu
- Laboratory for retinal cell biology, Department of Ophthalmology, University Clinic Zurich, Frauenklinikstrasse, and Research Laboratory for Calcium Metabolism, Orthopedic University Hospital Balgrist, Zurich, Switzerland
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Seiler T, Hafezi F. Customized Ablation – klinisch sinnvoll oder nur PR-Instrument? Klin Monbl Augenheilkd 2004. [DOI: 10.1055/s-2004-820180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Neeracher N, Iseli HP, Ganter C, Saupe N, Hafezi F. [Hypopigmentation of the fundus oculi and pulmonary fibrosis]. Ophthalmologe 2003; 100:480-1. [PMID: 12903633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
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Abstract
Age-related macular degeneration (AMD) is a main causes of severe visual impairment in the elderly in industrialized countries. The pathogenesis of this complex diseases is largely unknown, even though clinical characteristics and histopathology are well described. Because several aging changes are identical to those observed in AMD, there appears to exist an unknown switch mechanism from normal ageing to disease. Recent anatomical studies using elegant innovative techniques reveal that there is a 30% rod loss in normal ageing, which is increased in early AMD. Those and other observations by Curcio and co-workers indicate that early rod loss is an important denominator of AMD (Curcio CA. Eye 2001; 15:376). As in retinitis pigmentosa (RP), rods appear to die by apoptosis. Thus it seems mandatory to study the regulation of rod cell death in animal models to unravel possible mechanisms of rod loss in AMD. Our laboratory investigates signal transduction pathways and gene regulation of rod death in our model of light-induced apoptosis. The transcription factor AP1 is essential, whereas other classical pro- and antiapoptotic genes appear to be less important in our model system. Caspase-1 gene expression is distinctly upregulated after light exposure and there are several factors which completely protect against light-induced cell death, such as the anesthetic halothane, dexamethasone and the absence of bleachable rhodopsin during light exposure. A fast rhodopsin regeneration rate increased damage susceptibility. Our data indicate that rhodopsin is essential for the initiation of light-induced rod loss. Following photon absorption, there may be the generation of photochemically active molecules wich then induce the apoptotic death cascade.
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Affiliation(s)
- C E Remé
- Research Unit, Laboratory of Retinal Cell Biology, Department of Ophthalmology, University Hospital Zürich, Zürich, Switzerland
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Iseli HP, Wenzel A, Hafezi F, REme CE, Grimm C. Light damage susceptibility and RPE65 in rats. Exp Eye Res 2002; 75:407-13. [PMID: 12387788] [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: 02/26/2023]
Abstract
A sequence variation in the pigment epithelial protein RPE65 has been shown to correlate with RPE65 protein levels, rhodopsin regeneration kinetics and light damage susceptibility in different mouse strains. Here, we tested whether such a correlation can also be found in rats. We examined four rat strains for RPE65 protein levels and the Rpe65 gene sequence. In two strains, we additionally determined Rpe65 mRNA levels, rhodopsin regeneration and light damage susceptibility (LDS).RPE65 protein levels were higher in Lewis and Brown Norway rats compared to Wistar and Long Evans. The albino strains Wistar and Lewis were investigated further. Lewis had higher Rpe65 mRNA levels than Wistar. Sequence analysis of the coding region of the Rpe65 cDNA revealed no relevant sequence variations in the two strains. Content and regeneration of rhodopsin were comparable in both strains. However, Wistar rats were more susceptible to light damage than Lewis. We conclude that lower RPE65 protein levels in Wistar may have been caused by decreased gene expression and not by a sequence variation as suggested for mice. In rats, RPE65 may not be a limiting factor for rhodopsin regeneration. Since LDS in rats did not directly correlate with RPE65 protein levels and rhodopsin regeneration, other yet unidentified (genetic) factors may account for the susceptibility differences observed in rats.
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Affiliation(s)
- Hans Peter Iseli
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, University Hospital Zürich, Switzerland.
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Grimm C, Wenzel A, Behrens A, Hafezi F, Wagner EF, Remé CE. AP-1 mediated retinal photoreceptor apoptosis is independent of N-terminal phosphorylation of c-Jun. Cell Death Differ 2001; 8:859-67. [PMID: 11526439 DOI: 10.1038/sj.cdd.4400871] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2000] [Revised: 02/27/2001] [Accepted: 03/06/2001] [Indexed: 01/27/2023] Open
Abstract
Apoptosis is essential for retinal development but it is also a major mode of cell loss in many human retinal dystrophies. High levels of visible light induce retinal apoptosis in mice and rats. This process is dependent on the induction of the transcription factor AP-1, a dimeric complex composed of c-Fos and c-Jun/JunD phosphoproteins. While c-Fos is essential, JunD is dispensable for light-induced photoreceptor apoptosis. Here we show that N-terminal phosphorylation of c-Jun, the other main partner of c-Fos in induced AP-1 complexes is not required for programmed cell death during retinal development in vivo and is also dispensable for photoreceptor apoptosis induced by the exogenous stimuli "excessive light" and N-nitroso-N-methylurea (MNU). Mice expressing a mutant c-Jun protein (JunAA) that cannot be phosphorylated at its N-terminus are apoptosis competent and their retina is not distinguishable from wild-type mice. Accordingly, Jun kinase, responsible for phosphorylation of wild-type c-Jun protein is at best only marginally induced by the apoptotic stimuli "light" and MNU. Complex composition of light-induced AP-1 complexes is similar in wild-type and JunAA mice. This shows that the mutant c-Jun protein can be part of the DNA binding complex AP-1 and demonstrates that induction of the DNA binding activity of AP-1 after light insult does not depend on N-terminal phosphorylation of c-Jun. Our results suggest that transactivation of target genes by phosphorylated c-jun/AP-1 is not required for MNU- or light-induced apoptosis of photoreceptor cells.
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Affiliation(s)
- C Grimm
- Department of Ophthalmology, University Hospital, Frauenklinikstrasse 24, 8091 Zurich, Switzerland.
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Abstract
BACKGROUND Chamber angle changes due to trauma represent a diagnostic challenge in modern ophthalmology and two examination techniques are compared: gonioscopy which has been used in ophthalmology for almost a century and is still undergoing continuous improvements and ultrasound biomicroscopy (UBM) which was introduced into clinical ophthalmology in 1991. CASE REPORT We report the case of a 14-year-old boy with ocular trauma caused by a soft gun projectile. Gonioscopy showed a large goniosynechia in the presence of ocular hypotension, therefore, cyclodialysis was suspected. However, a control investigation using UBM showed an intact and circularly attached but anteverted ciliary body behind the synechia, a circular choroidal effusion and an anterior displacement of the iris-lens diaphragm. CONCLUSION In ocular trauma, UBM may under certain conditions clearly be of a higher diagnostic value than gonioscopy. Therefore, UBM should not only be considered as an additional examination technique in the evaluation of traumatic ocular pathologies but rather as the technique of choice.
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Wenzel A, Grimm C, Seeliger MW, Jaissle G, Hafezi F, Kretschmer R, Zrenner E, Remé CE. Prevention of photoreceptor apoptosis by activation of the glucocorticoid receptor. Invest Ophthalmol Vis Sci 2001; 42:1653-9. [PMID: 11381074] [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: 02/20/2023] Open
Abstract
PURPOSE Evidence has accumulated that excessive light exposure may promote age-related and inherited retinal degeneration, in which photoreceptor death by apoptosis leads to loss of vision. In the current study, the effect of elevated corticosteroid levels on light-induced apoptosis of photoreceptors was determined. METHODS Photoreceptor apoptosis was induced in retinas of BALB/c mice by exposure to diffuse white light. High levels of corticosteroids were induced, either endogenously (fasting-mediated stress) or by a single intraperitoneal injection of dexamethasone (DEX). Photoreceptor damage was assessed morphologically and by electroretinography. Glucocorticoid receptor (GR) and activator protein (AP)-1 activities were shown by Western blot analysis and electrophoretic mobility shift assay (EMSA) of retinal nuclear extracts. RESULTS Fasting and injection of DEX led to an activation of GR in the retina, as judged by its translocation to the nucleus of retinal cells. On induction of GR activity before light exposure, AP-1 activity, normally induced by damaging doses of light, remained at basal levels. Both treatments completely prevented photoreceptor apoptosis and preserved retinal function. CONCLUSIONS Activity of the transcription factor AP-1 is associated with light-induced apoptosis. In the current study, pharmacologic suppression of AP-1 activity protected against light damage. Inhibition of AP-1 activity may have occurred by the protein-protein interaction of GR and AP-1.
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MESH Headings
- Animals
- Apoptosis/radiation effects
- Blotting, Western
- Corticosterone/blood
- Dexamethasone/pharmacology
- Electroretinography
- Food Deprivation
- Glucocorticoids/pharmacology
- Injections, Intraperitoneal
- Light/adverse effects
- Male
- Mice
- Mice, Inbred BALB C
- Photoreceptor Cells, Vertebrate/drug effects
- Photoreceptor Cells, Vertebrate/metabolism
- Photoreceptor Cells, Vertebrate/radiation effects
- Radiation Injuries, Experimental/etiology
- Radiation Injuries, Experimental/metabolism
- Radiation Injuries, Experimental/pathology
- Radiation Injuries, Experimental/prevention & control
- Receptors, Glucocorticoid/metabolism
- Retinal Degeneration/etiology
- Retinal Degeneration/metabolism
- Retinal Degeneration/pathology
- Retinal Degeneration/prevention & control
- Transcription Factor AP-1/antagonists & inhibitors
- Transcription Factor AP-1/metabolism
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Affiliation(s)
- A Wenzel
- Laboratory of Retinal Cell Biology, University Hospital Zurich, Zürich, Switzerland.
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Abstract
BACKGROUND Idiopathic sclerochoroidal calcification is a rare benign disorder of the choroid and sclera which has initially been described twelve years ago. Clinically, it is often mistaken for osteoma, choroidal metastasis or infiltration in lymphoma leading to exentsive further investigations. CASE REPORT A 68-year-old patient had been referred to our outpatient clinic because of unusual fundus changes on both eyes. Ophthalmoscopic examination revealed a yellowish placoid-like lesion in the superotemporal quandrant of the fundus of both eyes, the left lesion being more discrete. Flurescein angiography and echography led to the diagnosis of bilateral ISC. CONCLUSION Although idiopathic sclerochoroidal calcification can easily be diagnosed by echographic and angiopraphic examination, it is frequently misdiagnosed for malignant tumors thus initiating excessive further investigation.
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Affiliation(s)
- F Hafezi
- Universitäts-Augenklinik Zürich, Frauenklinikstrasse 24, 8091 Zürich, Schweiz
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Keller C, Grimm C, Wenzel A, Hafezi F, Remé C. Protective effect of halothane anesthesia on retinal light damage: inhibition of metabolic rhodopsin regeneration. Invest Ophthalmol Vis Sci 2001; 42:476-80. [PMID: 11157886] [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: 02/18/2023] Open
Abstract
PURPOSE To determine whether the volatile anesthetic halothane protects against light-induced photoreceptor degeneration in the rodent retina. METHODS Albino mice and rats were anesthetized with halothane and exposed to high levels of white or blue light. Nonanesthetized animals served as controls. Retinal morphology was assessed by light microscopy, and apoptosis of photoreceptor cells was verified by detection of fragmented genomic DNA and in situ staining of apoptotic nuclei (TUNEL assay). Rhodopsin regeneration after bleaching was determined by measuring rhodopsin levels in retinas of mice or rats at different time points in darkness. RESULTS Halothane anesthesia reversibly inhibited metabolic rhodopsin regeneration and thus prevented rhodopsin from absorbing high numbers of photons during light exposure. Consequently, photoreceptors of mice and rats anesthetized with halothane were completely protected against degeneration induced by white light. In remarkable contrast, however, halothane anesthesia did not protect against blue-light-induced photoreceptor cell death. CONCLUSIONS After the initial bleach, halothane impeded photon absorption by rhodopsin by inhibiting metabolic rhodopsin regeneration. Apparently, the rhodopsin-mediated uptake of the critical number of photons to initiate white light-induced retinal degeneration was prevented. In contrast, halothane did not protect the retina against blue light. Blue light can efficiently restore functional rhodopsin from bleaching intermediates through a process termed photoreversal of bleaching. This process does not depend on the visual cycle via the pigment epithelium but nevertheless enables rhodopsin molecules to absorb the critical number of photons required to induce retinal degeneration.
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Affiliation(s)
- C Keller
- Department of Clinical Studies, University of Guelph, Guelph, Ontario, Canada
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31
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Grimm C, Wenzel A, Williams T, Rol P, Hafezi F, Remé C. Rhodopsin-mediated blue-light damage to the rat retina: effect of photoreversal of bleaching. Invest Ophthalmol Vis Sci 2001; 42:497-505. [PMID: 11157889] [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: 02/18/2023] Open
Abstract
PURPOSE Acute white-light damage to rods depends on the amount of rhodopsin available for bleaching during light exposure. Bleached rhodopsin is metabolically regenerated through the visual cycle involving the pigment epithelium, or photochemically by deep blue light through photoreversal of bleaching. Because photoreversal is faster than metabolic regeneration of rhodopsin by several orders of magnitude, the photon catch capacity of the retina is significantly augmented during blue-light illumination, which may explain the greater susceptibility of the retina to blue light than to green light. However, blue light can also affect function of several blue-light-absorbing enzymes that may lead to the induction of retinal damage. Therefore, this study was conducted to test whether rhodopsin and its bleaching intermediates play a role in blue-light-induced retinal degeneration. METHODS Eyes of anesthetized rats and mice that did or did not contain rhodopsin were exposed to green (550 +/- 10 nm) or deep blue (403 +/- 10 nm) light for up to 2 hours. Rats with nearly rhodopsinless retinas were obtained by bleaching rhodopsin in animals with inhibited metabolic rhodopsin regeneration-that is, under halothane anesthesia. In addition, Rpe65(-/-) mice that are completely without rhodopsin were used to test the susceptibility to blue-light damage of a rodent retina completely devoid of the visual pigment. Effects of illumination on photoreceptor morphology were assessed 24 hours or 10 days thereafter by morphologic and biochemical methods. RESULTS Exposure to blue light resulted in severe retinal damage and activation of the transcription factor AP-1 in rats. In contrast, green light had no effect. When rhodopsin was almost completely bleached by short-term green-light exposure while metabolic regeneration (but not photoreversal) was prevented by halothane anesthesia, blue-light exposure induced distinct lesions in rat retinas. When both metabolic rhodopsin regeneration and photoreversal of bleaching were almost completely inhibited, blue-light exposure caused only very moderate lesions. When mice without rhodopsin were exposed to blue light, no damage occurred, in contrast to wild-type control mice. CONCLUSIONS Short time exposure to blue light has deleterious effects on retinal morphology. Because damage was observed only in the presence of the visual pigment, blue-light-induced retinal degeneration is rhodopsin mediated. Absorption of blue light by other proteins is not sufficient to induce light damage. Photoreversal of bleaching, which occurs only in blue but not in green light, increases the photon-catch capacity of the retina and may thus account for the difference in the damage potential between blue and green light.
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Affiliation(s)
- C Grimm
- Department of Ophthalmology, University Eye Clinic, Zurich, Switzerland.
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Wenzel A, Reme CE, Williams TP, Hafezi F, Grimm C. The Rpe65 Leu450Met variation increases retinal resistance against light-induced degeneration by slowing rhodopsin regeneration. J Neurosci 2001; 21:53-8. [PMID: 11150319 PMCID: PMC6762429] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2000] [Revised: 10/02/2000] [Accepted: 10/20/2000] [Indexed: 02/18/2023] Open
Abstract
Excessive light can cause retinal degeneration and may be an environmental cofactor accelerating retinal dystrophies and age-related diseases. In rodent models, the light damage susceptibility (LDS) of the retina is determined genetically. In two mouse strains, with different degrees of LDS, a Leu450Met variation in the pigment epithelial protein RPE65 was shown recently to cosegregate with low LDS. Because light damage is rhodopsin-mediated, and RPE65 is essential for the regeneration of rhodopsin in the visual cycle, we analyzed this variation regarding rhodopsin metabolism and LDS in four mouse strains. We found that, in contrast to previous assertions, LDS does not correlate with the maximal retinal content of rhodopsin present after dark adaptation. Instead, LDS correlated positively with the kinetics of rhodopsin regeneration, which determine rhodopsin availability during light exposure. Light damage occurred after absorption of a threshold dose of photons and thus fast regeneration, as observed in those two strains having Leu at position 450 of RPE65, was correlated with the occurrence of photoreceptor apoptosis after short exposure. In contrast, mice with the Leu450Met variation of Rpe65 regenerated rhodopsin with slow kinetics and showed an increased resistance to light-induced retinal degeneration. In these mice, RPE65 protein levels were reduced by a post-transcriptional mechanism. F(1) hybrid mice, carrying one normal and one variant Rpe65 gene, had intermediate levels of the corresponding protein and showed intermediate rhodopsin regeneration kinetics and an intermediate LDS. Thus, none of the two variants of Rpe65 had a dominant effect.
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Affiliation(s)
- A Wenzel
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, University Hospital Zürich, CH-8091 Zürich, Switzerland
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33
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Grimm C, Wenzel A, Hafezi F, Remé CE. Gene expression in the mouse retina: the effect of damaging light. Mol Vis 2000; 6:252-60. [PMID: 11134582] [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: 02/18/2023] Open
Abstract
PURPOSE High levels of visible light induce apoptotic cell death of photoreceptors, a process depending on the activation of the transcription factor AP-1. This suggests that regulation of gene expression might be important for light-induced photoreceptor cell death. We measured expression of AP-1 family members and of several apoptosis-related genes to test their potential involvement in photoreceptor apoptosis. METHODS Wildtype and c-fos-/- mice were exposed to low (roomlight) or high levels of visible light for up to two hours. Total RNA was prepared from isolated retinas during and after light exposure. Relative mRNA levels were determined semiquantitatively using either competitive or exponential RT-PCR. RESULTS Expression of c-fos-/- was upregulated by intense light as early as 15 min after lights on. Highest levels (6-fold induction) were detected at 2 h after lights off declining thereafter to basal levels 20 h after the end of exposure. c-jun mRNA was induced at 30 min after lights on and high expression levels (fourfold induction) persisted at least for 8 h. Similarly, expression of caspase-1 was six to 9-fold increased at 6 to 8 h after light exposure in wildtype but not in c-fos knockout mice. The latter mice are protected against light-induced photoreceptor apoptosis. Expression of other apoptosis-related genes (bcl-2, bcl-XL, bax, bad, caspase-3) was not affected by light exposure or the lack of c-Fos in knockout mice. CONCLUSIONS Expression of c-fos and c-jun mRNA is transiently induced by exposure to damaging light. Induced expression of c-jun persists longer than expression of c-fos. Among the apoptosis-related genes, only caspase-1 expression was upregulated by light exposure and Caspase-1 might therefore be involved in light-induced retinal degeneration.
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MESH Headings
- Animals
- Apoptosis/radiation effects
- Caspase 1/biosynthesis
- Caspase 1/genetics
- DNA Primers/chemistry
- Female
- Gene Expression
- Light/adverse effects
- Male
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- Mice, Knockout
- Photoreceptor Cells, Vertebrate/metabolism
- Photoreceptor Cells, Vertebrate/pathology
- Photoreceptor Cells, Vertebrate/radiation effects
- Proto-Oncogene Proteins c-bcl-2/biosynthesis
- Proto-Oncogene Proteins c-bcl-2/genetics
- Proto-Oncogene Proteins c-fos/biosynthesis
- Proto-Oncogene Proteins c-fos/genetics
- Proto-Oncogene Proteins c-jun/biosynthesis
- Proto-Oncogene Proteins c-jun/genetics
- RNA, Messenger/biosynthesis
- Radiation Injuries, Experimental/genetics
- Radiation Injuries, Experimental/metabolism
- Radiation Injuries, Experimental/pathology
- Retinal Degeneration/genetics
- Retinal Degeneration/metabolism
- Retinal Degeneration/pathology
- Reverse Transcriptase Polymerase Chain Reaction
- Transcription Factor AP-1/biosynthesis
- Transcription Factor AP-1/genetics
- Up-Regulation
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Affiliation(s)
- C Grimm
- Department of Ophthalmology, University Eye Clinic, Zurich, Switzerland.
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34
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Abstract
Structure-function analysis as well as studies with knock-out and transgenic mice have assigned distinct functions to c-Fos and Fra-1, two components of the transcription factor AP-1 (activator protein-1). To test whether Fra-1 could substitute for c-Fos, we generated knock-in mice that express Fra-1 in place of c-Fos. Fra-1 rescues c-Fos-dependent functions such as bone development and light-induced photoreceptor apoptosis. Importantly, rescue of bone cell differentiation, but not photoreceptor apoptosis, is gene-dosage dependent. Moreover, Fra-1 fails to substitute for c-Fos in inducing expression of target genes in fibroblasts. These results show that c-Fos and Fra-1 have maintained functional equivalence during vertebrate evolution.
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Affiliation(s)
- A Fleischmann
- Research Institute of Molecular Pathology (IMP), A-1030 Vienna, Austria
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35
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Hafezi F, Grimm C, Simmen BC, Wenzel A, Remé CE. Molecular ophthalmology: an update on animal models for retinal degenerations and dystrophies. Br J Ophthalmol 2000; 84:922-7. [PMID: 10906106 PMCID: PMC1723576 DOI: 10.1136/bjo.84.8.922] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- F Hafezi
- Department of Ophthalmology, University Clinic Zurich, Switzerland.
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36
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Abstract
Death of retinal photoreceptors by apoptosis is observed under many physiological and pathological conditions such as histogenesis, retinal dystrophies and light-induced photoreceptor degeneration. To date, little is known about regulatory mechanisms for apoptosis in the retina. The tumor suppressor gene p53 is a regulator of apoptosis in a number of systems, however, p53-independent apoptosis has also been described. We have therefore investigated whether the lack of p53 influences the dark-adapted ERG in C57BL/6 p53-/- mice compared to p53+/+ control littermates under physiological (regular light-dark cycle) conditions. We also recorded ERGs at 12 to 14 h in darkness following diffuse bright light exposure to 8,000 or 15,000 lux for 2 h. ERG analysis over a range of 6 logarithmic units of light intensity revealed normal and virtually identical a-, b-, c-waves and oscillatory potentials in dark-adapted p53+/+ and p53-/- mice. After exposure to diffuse white fluorescent light strong decreases of all ERG components were found to be very similar in both genotypes. These data support the notion that the p53 protein is neither essential for normal retinal function nor for processes involved in light-induced depression of the ERG in mice.
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Affiliation(s)
- N Lansel
- Dept of Ophthalmology, University Hospital, Zurich. Switzerland
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37
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Grimm C, Wenzel A, Hafezi F, Yu S, Redmond TM, Remé CE. Protection of Rpe65-deficient mice identifies rhodopsin as a mediator of light-induced retinal degeneration. Nat Genet 2000; 25:63-6. [PMID: 10802658 DOI: 10.1038/75614] [Citation(s) in RCA: 185] [Impact Index Per Article: 7.7] [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: 12/24/2022]
Abstract
Light-induced apoptosis of photoreceptors represents an animal model for retinal degeneration. Major human diseases that affect vision, such as age-related macular degeneration (AMD) and some forms of retinitis pigmentosa (RP), may be promoted by light. The receptor mediating light damage, however, has not yet been conclusively identified; candidate molecules include prostaglandin synthase, cytochrome oxidase, rhodopsin, and opsins of the cones and the retinal pigment epithelium (PE). We exposed to bright light two groups of genetically altered mice that lack the visual pigment rhodopsin (Rpe65-/- and Rho-/-). The gene Rpe65 is specifically expressed in the PE and essential for the re-isomerization of all-trans retinol in the visual cycle and thus for the regeneration of rhodopsin after bleaching. Rho-/- mice do not express the apoprotein opsin in photoreceptors, which, consequently, do not contain rhodopsin. We show that photoreceptors lacking rhodopsin in these mice are completely protected against light-induced apoptosis. The transcription factor AP-1, a central element in the apoptotic response to light, is not activated in the absence of rhodopsin, indicating that rhodopsin is essential for the generation or transduction of the intracellular death signal induced by light.
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Affiliation(s)
- C Grimm
- Laboratory of Retinal Cell Biology, Department of Ophthalmology, University Hospital Zurich, Zurich, Switzerland.
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38
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Kueng-Hitz N, Grimm C, Lansel N, Hafezi F, He L, Fox DA, Remé CE, Niemeyer G, Wenzel A. The retina of c-fos-/- mice: electrophysiologic, morphologic and biochemical aspects. Invest Ophthalmol Vis Sci 2000; 41:909-16. [PMID: 10711713] [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: 02/15/2023] Open
Abstract
PURPOSE Mice without a functional c-Fos protein (c-fos-/- mice) do not exhibit light-induced apoptotic cell death of rods in contrast to their wild-type littermates (c-fos+/+ mice). To analyze the consequences of the absence of c-fos in the retina, we investigated whether the retinas of c-fos-/- mice have a reduced capacity to absorb and transduce light compared with c-fos+/+ mice. METHODS Retinal function was evaluated in dark-adapted mice by full-field electroretinograms (ERGs) over more than 6 log units of intensity. Retinal morphology was studied by light- and electron microscopy. Arrestin and the heat shock protein 70 (Hsp70) were detected by Western blot analysis. The rhodopsin content and the kinetics of rhodopsin regeneration were determined in retinal extracts. RESULTS Although the configuration of the ERGs was comparable in both groups of mice, c-fos-/- mice showed a marked variability in all quantitative ERG-measures with lower mean amplitudes, longer latencies, and a 0.9-log-unit lower b-wave sensitivity on average. Morphometry showed that c-fos-/- mice have 23% fewer rods on average, whereas the number of cones was comparable among c-fos+/+ and c-fos-/- mice. Arrestin levels appeared slightly reduced in c-fos-/- mice when compared with c-fos+/+ mice, whereas Hsp70 levels were comparable in both genotypes. The kinetics of rhodopsin regeneration were similar, but c-fos-/- mice had a 25% lower rhodopsin content on average. CONCLUSIONS Compared with c-fos+/+ mice, retinal function in c-fos-/- mice is attenuated to a variable but marked degree, which may be, at least in part, related to the reduced number of rods and the reduced rhodopsin content. However, c-fos does not appear to be essential for the ability to absorb photons, nor for phototransduction or the function of second-order neurons. The resistance to light-induced apoptosis of photoreceptor cells in c-fos-/- mice may result from the acute deficit of c-fos in the apoptotic cascade rather than from developmental deficits affecting rod photoreceptor function.
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Affiliation(s)
- N Kueng-Hitz
- Department of Ophthalmology, University Hospital Zurich, Switzerland
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Abstract
BACKGROUND The term "hippus" describes pupillary oscillations of variable amplitude and frequency and may be physiological or part of a pathological entity. Thus, pupillary hippus is often the target of extensive clinical investigation. CASE REPORT A 9-year-old boy was seen in our emergency room in March 1998. Examination showed distinct pupillary oscillations in the absence of any other pathological findings. We presented the patient to a pediatric neurologist. Apart from a history of enuresis and of motor tics in the neck region, the present neurological examination was normal. CONCLUSIONS Even a pronounced hippus may be physiological and does not necessarily require extensive diagnostic investigations.
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Affiliation(s)
- F Hafezi
- Universitäts-Augenklinik Zürich.
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Abegg M, Hafezi F, Wenzel A, Grimm C, Remé CE. [Therapeutic strategies in RP (retinitis pigmentosa): light at the end of the tunnel?]. Klin Monbl Augenheilkd 2000; 216:83-9. [PMID: 10730223 DOI: 10.1055/s-2000-10523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Retinitis pigmentosa (RP) is a hereditary retinal dystrophy which leads to severe visual impairment or blindness and affects about 3.5/1000 of individuals in the industrial world. During the past decades, numerous animal models carrying mutations analogous to mutations in human RP have been studied to elucidate the molecular mechanisms leading to apoptotic photoreceptor cell death in this disease. Up to date, there is no effective treatment to influence the fatal outcome of RP. Recent progress in basic research promotes the development of new therapeutic strategies. In order to restore visual function in blind individuals, the development of electronic photoreceptor prosthesis is being investigated by several researchgroups. Other promising approaches are somatic gene therapy, the application of growth factors and/or pharmacological agents and the inhibition of photoreceptor cell death by interfering with the apoptotic pathway. However, a better understanding of the molecular events leading to cell loss due to photoreceptor apoptosis will be essential for the development of effective treatment.
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Affiliation(s)
- M Abegg
- Labor für Zellbiologie der Netzhaut, Universitäts-Augenklinik Zürich
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41
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Wenzel A, Grimm C, Marti A, Kueng-Hitz N, Hafezi F, Niemeyer G, Remé CE. c-fos controls the "private pathway" of light-induced apoptosis of retinal photoreceptors. J Neurosci 2000; 20:81-8. [PMID: 10627584 PMCID: PMC6774101] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023] Open
Abstract
White light (5 klux for 2 hr) induces apoptosis of rod photoreceptors in wild-type mice (c-fos(+/+)) within 24 hr, whereas rods of c-fos knock-out mice (c-fos(-/-)) are protected (). The range of this protection was tested by analyzing retinas of c-fos(+/+) and c-fos(-/-) mice up to 10 d after exposure to threefold increased light intensities (15 klux for 2 hr). In c-fos(-/-) mice, rods were unaffected, whereas they were destroyed in c-fos(+/+) mice. After light exposure, mitochondrial damage in rods was observed exclusively in c-fos(+/+) mice. Electroretinograms recorded 48 hr after exposure revealed a decrease of all components in c-fos(+/+) mice but indicated no light-induced loss of function in c-fos(-/-) mice. Thus, in c-fos(-/-) mice, light-induced apoptosis is blocked or its threshold is elevated more than threefold. Increased activity of the transcription factor activator protein-1 (AP-1) in retinas of light-exposed c-fos(+/+) mice indicated an acute contribution of AP-1 to apoptosis induction. AP-1 activity increased already during exposure and peaked approximately 6 hr thereafter, coinciding with the appearance of major morphological signs of apoptosis. Activated AP-1 mainly consisted of c-Fos/Jun heterodimers. In c-fos(-/-) mice, AP-1 activity remained unchanged, indicating that no other Jun- or Fos-family member could substitute for c-Fos. Like damaging light, N-methyl-N-nitrosourea (MNU) induced AP-1 containing c-Fos in c-fos(+/+) mice and did not induce AP-1 in c-fos(-/-) mice. In contrast to light, however, MNU induced apoptosis in rods of c-fos(-/-) mice. Thus, c-Fos is essential for a specific premitochondrial "private apoptotic pathway" induced by light but not for the execution of apoptosis induced by other stimuli.
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Affiliation(s)
- A Wenzel
- Department of Ophthalmology, University Hospital Zürich, CH-8091 Zürich, Switzerland.
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Hafezi F, Grimm C, Wenzel A, Abegg M, Yaniv M, Remé CE. Retinal photoreceptors are apoptosis-competent in the absence of JunD/AP-1. Cell Death Differ 1999; 6:934-6. [PMID: 10617374 DOI: 10.1038/sj.cdd.4400574] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
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Remé CE, Wolfrum U, Imsand C, Hafezi F, Williams TP. Photoreceptor autophagy: effects of light history on number and opsin content of degradative vacuoles. Invest Ophthalmol Vis Sci 1999; 40:2398-404. [PMID: 10476808] [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: 02/13/2023] Open
Abstract
PURPOSE To investigate whether regulation of rhodopsin levels as a response to changed lighting environment is performed by autophagic degradation of opsin in rod inner segments (RISs). METHODS Groups of albino rats were kept in 3 lux or 200 lux. At 10 weeks of age, one group was transferred from 3 lux to 200 lux, another group was switched from 200 lux to 3 lux, and two groups remained in their native lighting (baselines). Rats were killed at days 1, 2, and 3 after switching. Another group was switched from 3 lux to 200 lux, and rats were killed at short intervals after the switch. Numbers of autophagic vacuoles (AVs) in RISs were counted, and immunogold labeling was performed for opsin and ubiquitin in electron microscopic sections. RESULTS The number of AVs increased significantly after switching from 3 lux to 200 lux at days 1 and 2 and declined at day 3, whereas the reverse intensity change did not cause any increase. Early time points after change from 3 lux to 200 lux showed a significant increase of AVs 2 and 3 hours after switching. Distinct opsin label was observed in AVs of rats switched to 200 lux. Ubiquitin label was present in all investigated specimens and was also seen in AVs especially in 200-lux immigrants. CONCLUSIONS Earlier studies had shown that an adjustment to new lighting environment is performed by changes in rhodopsin levels in ROSs. Autophagic degradation of opsin or rhodopsin may subserve, at least in part, the adaptation to abruptly increased habitat illuminance by removing surplus visual pigment.
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Affiliation(s)
- C E Remé
- University Eye Clinic, Zurich, Switzerland.
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Hafezi F, Marti A, Grimm C, Wenzel A, Remé CE. Differential DNA binding activities of the transcription factors AP-1 and Oct-1 during light-induced apoptosis of photoreceptors. Vision Res 1999; 39:2511-8. [PMID: 10396620 DOI: 10.1016/s0042-6989(98)00313-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
The activity of transcription factors like AP-1 and Oct-1 is critical for the regulation of gene expression. Whereas Oct-1 mainly regulates the expression of housekeeping genes, AP-1 is often involved in cellular responses to external stimuli and plays an essential role in the regulation of light-induced apoptosis of mouse retinal photoreceptors. In this study, we investigated AP-1 and Oct-1 DNA binding activity and AP-1 complex composition in the mouse retina during light-induced photoreceptor apoptosis. AP-1 DNA binding activity was low in dark-adapted animals but was transiently elevated within 12 h after exposure of mice to apoptosis-inducing levels of white fluorescent light. Maximal AP-1 activity was found 6 h after light-exposure. Antibody interference analysis at 6 h after damaging light exposure and under normal light conditions revealed that the major fraction of AP-1 consists of c-Fos/JunD heterodimers in both situations. In contrast to AP-1, Oct-1 DNA binding activity was maximal in dark-adapted animals and was reduced during photoreceptor apoptosis. Transient induction of AP-1 (c-Fos/JunD) and inactivation of Oct-1 may be crucial events for light-mediated apoptosis of retinal photoreceptors.
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Affiliation(s)
- F Hafezi
- Department of Ophthalmology, University Hospital, Zurich, Switzerland.
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Hafezi F, Abegg M, Grimm C, Wenzel A, Munz K, Stürmer J, Farber DB, Remé CE. Retinal degeneration in the rd mouse in the absence of c-fos. Invest Ophthalmol Vis Sci 1998; 39:2239-44. [PMID: 9804131] [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: 02/09/2023] Open
Abstract
PURPOSE Apoptosis is the final common death pathway of photoreceptors in light-induced retinal degeneration and in several animal models for retinal dystrophy. To date, little is known about gene regulation of apoptosis in the retina. The expression of the immediate early gene c-fos is upregulated concomitant with apoptosis in light-induced photoreceptor degeneration and in the rd mouse, an animal model for inherited retinal degeneration. In a recent study it was shown that c-Fos is essential for light-induced apoptosis of photoreceptors in vivo. To determine whether c-Fos is also involved in the apoptotic pathway of inherited retinal degeneration, rd/rd, c-fos -/- double-mutant mice have been generated. METHODS Double-mutant mice (rd/rd, c-fos -/-) were crossbred from c-fos+/- mice and rd/rd mice. Their genotype was determined by polymerase chain reaction analysis of genomic DNA. Wild-type control mice and homozygous rd mice were killed at 2-day intervals from postnatal day (P)9 through P21. Double-mutant mice were killed at postnatal days P9, P11, P13, P15, and P21. To determine levels of apoptosis in the retina, eyes were enucleated and processed for light microscopy and in situ nick-end labeling. Total retinal DNA was extracted from isolated retinas for DNA fragmentation analysis. RESULTS Morphologic, histochemical, and biochemical analyses showed that the time course of apoptosis and the outcome of photoreceptor degeneration in rd/rd, c-fos-/- double-mutant mice was indistinguishable from that in rd mice carrying functional c-fos. CONCLUSIONS These data suggest that in contrast to its role in light-induced photoreceptor degeneration, c-Fos is not essential for apoptosis in the rd mouse.
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Affiliation(s)
- F Hafezi
- Department of Ophthalmology, University Hospital, Zurich, Switzerland
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Abstract
Apoptosis is a regulated mode of single cell death that involves gene expression in many instances and occurs under physiological and pathological conditions in a large variety of systems. We briefly summarize major features of apoptosis in general and describe the occurrence of apoptosis in the retina in different situations that comprise animal models of retinitis pigmentosa, light-induced lesions, histogenesis during development, and others. Apoptosis can be separated into several phases: the induction by a multitude of stimuli, the effector phase in which the apoptotic signal is transmitted to the cellular death machinery, the excecution period when proteolytic cascades are activated, and the phagocytic removal of cellular remnants. Control mechanisms for retinal apoptosis are only beginning to be clarified. Potential apoptotic signal transducers were investigated in our laboratory, including metabolites of arachidonic acid and downstream mediators of signaling molecules such as transcription factors. Work in our laboratory revealed an essential role of the immediate-early gene product c-Fos in light-induced apoptosis. c-Fos is a member of the AP-1 family of transcription factors and, together with other members of this family, it may regulate apoptosis in the central nervous system. Expression of the c-fos gene in the retina can be evoked by light exposure and follows a diurnal rhythm. Future studies will have to clarify how light can control the expression of specific genes, and specifically, the role of c-fos and other genes of retinal apoptosis including potential target genes and signaling pathways.
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Affiliation(s)
- C E Remé
- Department of Ophthalmology, University Hospital, Zuerich, Switzerland.
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Abstract
BACKGROUND Apoptosis is a gene-regulated mode of cell death which gains increasing importance in retinal pathologies such as retinitis pigmentosa, retinal detachment and proliferative vitreoretinopathy. A better understanding of the regulation of apoptosis could imply the means to reduce photoreceptor cell death and thereby provide therapeutic strategies to influence the time course of retinal diseases. Previous studies in our laboratory demonstrated that light induces apoptosis in the rat retina in vivo as a function of light dose. In several cell systems, oxidative stress including oxygenated metabolites of arachidonic acid (AA) was found to evoke apoptosis. We have observed a light-elicited release of AA and the subsequent formation of its metabolites in the rat retina. Therefore, AA and its metabolites appeared to be suitable candidates for the induction of apoptosis during light exposure. MATERIALS AND METHODS Isolated rat retinas were incubated for 60, 120 and 180 min, respectively, with and without the addition of 30 mumol 5S-hydroperoxyeicosatetraenoic acid (5-HPETE). Retinas were then processed for light- and electron microscopy and examined for the morphological signs of apoptosis. The rate of apoptosis in the outer nuclear layer was assessed quantitatively. RESULTS 5S-HPETE induces apoptosis of photoreceptors in the rat retina in vitro. Quantitative analysis revealed a significant increase in the rate of apoptosis of 5S-HPETE-treated retinas when compared to untreated controls. CONCLUSION Arachidonic acid metabolites released upon light exposure may represent messenger candidates for apoptosis in the retina.
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Affiliation(s)
- F Hafezi
- Universitäts-Augenklinik Zürich, Labor für Zellbiologie der Netzhau
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Marti A, Hafezi F, Lansel N, Hegi ME, Wenzel A, Grimm C, Niemeyer G, Remé CE. Light-induced cell death of retinal photoreceptors in the absence of p53. Invest Ophthalmol Vis Sci 1998; 39:846-9. [PMID: 9538895] [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: 02/07/2023] Open
Abstract
PURPOSE Cell death by apoptosis is essential for normal development and tissue homeostasis, and it is involved also in a variety of pathologic processes. Apoptosis is the final common pathway of photoreceptor cell death in retinal dystrophies and degeneration. So far, little is known about genes regulating apoptosis in the retina. The tumor-suppressor gene product p53 is a potent regulator of apoptosis in numerous systems. However, p53-independent apoptotic pathways also have been described. In this study the authors investigated the role of p53 in the light-induced apoptosis of retinal photoreceptors using mice lacking p53. METHODS Free-moving p53-/- and p53+/+ mice were dark adapted and were exposed to 8,500 or 15,000 lux of diffuse, cool, white fluorescent light for 2 hours. Animals were killed before and immediately after light exposure or at 12 hours in darkness after light exposure. Eyes were enucleated and processed for light and electron microscopy and histochemistry (TdT-dUTP terminal nick-end labeling method). Isolated retinas were subjected to the extraction of total retinal DNA. Electroretinogram (ERG) recordings were performed at all time points. RESULTS Morphologic, biochemical, histochemical, and ERG analysis showed that the retinas of untreated p53-/- mice and wild-type control mice were structurally and functionally indistinguishable. After exposure to diffuse white fluorescent light, light-induced photoreceptor cell death was analyzed and was found to be the same in both groups of mice. CONCLUSIONS These data suggest that light-induced apoptosis of photoreceptors is independent of functional p53.
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Affiliation(s)
- A Marti
- Department of Ophthalmology, University Hospital, Zurich, Switzerland
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Abstract
Apoptosis is a genetically regulated form of cell death. Individual cells show condensed nuclear chromatin and cytoplasm, and biochemical analysis reveals fragmentation of the DNA. Ensuing cellular components, apoptotic bodies, are removed by macrophages or neighboring cells. Genes involved in the regulation of apoptosis as well as stimuli and signal transduction systems, are only beginning to be understood in the retina. Therefore, we developed a new in vivo model system for the investigation of events leading to apoptosis in the retina and the pigment epithelium. We induced apoptosis in retinal photoreceptors and the pigment epithelium of albino rats by exposure to 3000 lux of diffuse, cool white fluorescent light for short time periods of up to 120 minutes. Animals were killed at different time intervals during and after light exposure. The eyes were enucleated and the lower central retina was processed for light- and electron microscopy. DNA fragmentation was analysed in situ by TdT-mediated dUTP nick-end labeling (TUNEL) or by gel electrophoresis of total retinal DNA. We observed that the timing of apoptosis in the photoreceptors and pigment epithelium was remarkably different, the pigment epithelium showing a distinct delay of several hours before the onset of apoptosis. In photoreceptors, apoptosis was induced within 90 minutes of light exposure, with the morphological appearance of apoptosis preceding the fragmentation of DNA. In the pigment epithelium, the morphological appearance of apoptosis and DNA fragmentation were coincident. Different regulative mechanisms may lead to apoptotic cell death in the retinal photoreceptors and pigment epithelium. This in vivo model system will allow measurement of dose-responses, a potential spectral dependence and the molecular background of apoptotic mechanisms in the retina.
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Affiliation(s)
- F Hafezi
- Department of Ophthalmology, University Hospital, Zurich, Switzerland
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Hafezi F, Steinbach JP, Marti A, Munz K, Wang ZQ, Wagner EF, Aguzzi A, Remé CE. The absence of c-fos prevents light-induced apoptotic cell death of photoreceptors in retinal degeneration in vivo. Nat Med 1997; 3:346-9. [PMID: 9055866 DOI: 10.1038/nm0397-346] [Citation(s) in RCA: 194] [Impact Index Per Article: 7.2] [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: 02/03/2023]
Abstract
Apoptotic cell death in the retina was recently demonstrated in animal models of the hereditary human retinal dystrophy known as retinitis pigmentosa. Although recent evidence indicates that the proto-oncogene c-fos is a mediator of apoptosis, its precise role is unclear. In fact, under some conditions, c-fos may even protect against apoptotic cell death. In the retina, c-fos is physiologically expressed in a diurnal manner and is inducible by light. We previously observed a light-elicited, dose-dependent apoptotic response in rat photoreceptors. To determine whether c-fos is involved in the light-induced apoptotic pathway we have used control mice and mice lacking c-fos. We found that following dark adaptation and two hours of light exposure both groups of animals exhibited only a few apoptotic cells. However, at 12 and 24 additional hours after light exposure, apoptosis increased dramatically in controls but was virtually absent in those mice lacking c-fos. Therefore, c-fos is essential for light-induced apoptosis of photoreceptors. Notably, c-fos is continuously upregulated concomitant with apoptotic photoreceptor death in our system and in animal models of retinitis pigmentosa (Agarwal, N. et al., Invest. Ophthalmol. Vis.Sci. Suppl. 36, S638 and Rich, K.A. et al., Invest. Ophthalmol. Vis. Sci. Suppl. 35, 1833). Inhibition of c-fos expression might therefore represent a novel therapeutic strategy to retard the time course of retinal dystrophies and light-induced retinal degeneration.
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Affiliation(s)
- F Hafezi
- Department of Ophthalmology, University Clinic, Zurich, Switzerland
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