External Limiting Membrane, Photoreceptor Ellipsoid Zone Disruption, and Retinal Pigment Epithelium Alterations in Diabetic Retinopathy
Objective Diabetic retinopathy (DR), a microvascular complication of diabetes, is a leading cause of preventable blindness. Spectral domain optical coherence tomography (SD-OCT) provides cross-sectional and topographical imaging of the retina. SD-OCT resolves outer retinal layers into three hyperref...
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Thieme Medical and Scientific Publishers Pvt. Ltd.
2022-07-01
|
| Series: | Annals of the National Academy of Medical Sciences (India) |
| Subjects: | |
| Online Access: | http://www.thieme-connect.de/DOI/DOI?10.1055/s-0042-1742585 |
| _version_ | 1811295129861881856 |
|---|---|
| author | Nibha Mishra Gurkiran Kaur Sandeep Saxena |
| author_facet | Nibha Mishra Gurkiran Kaur Sandeep Saxena |
| author_sort | Nibha Mishra |
| collection | DOAJ |
| description | Objective Diabetic retinopathy (DR), a microvascular complication of diabetes, is a leading cause of preventable blindness. Spectral domain optical coherence tomography (SD-OCT) provides cross-sectional and topographical imaging of the retina. SD-OCT resolves outer retinal layers into three hyperreflective bands—external limiting membrane (ELM), ellipsoid zone (EZ), and retinal pigment epithelium (RPE). In this article, we have studied the role of these outer retinal layers in structural and molecular changes taking place in DR.
Materials and Methods Articles with clinical features, pathogenesis, diagnosis, and treatment of DR were thoroughly studied. Articles were searched on PubMed, MEDLINE, and Cochrane Library from 2000 to 2020. Studies focusing on the role of ELM, EZ, and RPE in pathogenesis of DR based on SD-OCT were included.
Results The long-standing hyperglycemia leads to protein glycosylation resulting in formation of advanced glycation end products (AGEs). AGEs have an impact through their effect on retinal microvasculature, vascular endothelial growth factor (VEGF), intercellular adhesion molecule-1, nitrosative and oxidative stress, and vitamin D and calcium metabolism. All these factors have been linked with disruption of outer retinal layers. AGEs lead to vascular endothelial dysfunction and release of proangiogenic factors by increasing the expression of VEGF in retinal pericytes and RPE cells. This leads to leakage and fluid accumulation resulting in diabetic macular edema (DME). In DME, there is sequential disruption of ELM and EZ and decrease in visual acuity (VA). The RPE alterations have been reported to be associated with the severity of DR and decrease in VA. Anti-VEGF therapy, most common treatment of DME, leads to restoration of barrier effect of ELM, it was found to be restored first followed by EZ restoration. Newer anti-AGEs agents and their receptor blockers are being developed which have a positive effect on maintaining the health of RPE.
Conclusion A complex molecular association exists between the structural changes in ELM, EZ, and RPE in DR. SD-OCT is an indispensable tool to study these changes as integrity of these outer layers of retina is essential for maintaining visual function of retina in DR. |
| first_indexed | 2024-04-13T05:27:58Z |
| format | Article |
| id | doaj.art-ce1118c294f54c758c7cdb6b88a44663 |
| institution | Directory Open Access Journal |
| issn | 0379-038X 2454-5635 |
| language | English |
| last_indexed | 2024-04-13T05:27:58Z |
| publishDate | 2022-07-01 |
| publisher | Thieme Medical and Scientific Publishers Pvt. Ltd. |
| record_format | Article |
| series | Annals of the National Academy of Medical Sciences (India) |
| spelling | doaj.art-ce1118c294f54c758c7cdb6b88a446632022-12-22T03:00:32ZengThieme Medical and Scientific Publishers Pvt. Ltd.Annals of the National Academy of Medical Sciences (India)0379-038X2454-56352022-07-01580311912410.1055/s-0042-1742585External Limiting Membrane, Photoreceptor Ellipsoid Zone Disruption, and Retinal Pigment Epithelium Alterations in Diabetic RetinopathyNibha Mishra0Gurkiran Kaur1Sandeep Saxena2Department of Ophthalmology, King George's Medical University, Lucknow, Uttar Pradesh, IndiaDepartment of Ophthalmology, King George's Medical University, Lucknow, Uttar Pradesh, IndiaDepartment of Ophthalmology, King George's Medical University, Lucknow, Uttar Pradesh, IndiaObjective Diabetic retinopathy (DR), a microvascular complication of diabetes, is a leading cause of preventable blindness. Spectral domain optical coherence tomography (SD-OCT) provides cross-sectional and topographical imaging of the retina. SD-OCT resolves outer retinal layers into three hyperreflective bands—external limiting membrane (ELM), ellipsoid zone (EZ), and retinal pigment epithelium (RPE). In this article, we have studied the role of these outer retinal layers in structural and molecular changes taking place in DR. Materials and Methods Articles with clinical features, pathogenesis, diagnosis, and treatment of DR were thoroughly studied. Articles were searched on PubMed, MEDLINE, and Cochrane Library from 2000 to 2020. Studies focusing on the role of ELM, EZ, and RPE in pathogenesis of DR based on SD-OCT were included. Results The long-standing hyperglycemia leads to protein glycosylation resulting in formation of advanced glycation end products (AGEs). AGEs have an impact through their effect on retinal microvasculature, vascular endothelial growth factor (VEGF), intercellular adhesion molecule-1, nitrosative and oxidative stress, and vitamin D and calcium metabolism. All these factors have been linked with disruption of outer retinal layers. AGEs lead to vascular endothelial dysfunction and release of proangiogenic factors by increasing the expression of VEGF in retinal pericytes and RPE cells. This leads to leakage and fluid accumulation resulting in diabetic macular edema (DME). In DME, there is sequential disruption of ELM and EZ and decrease in visual acuity (VA). The RPE alterations have been reported to be associated with the severity of DR and decrease in VA. Anti-VEGF therapy, most common treatment of DME, leads to restoration of barrier effect of ELM, it was found to be restored first followed by EZ restoration. Newer anti-AGEs agents and their receptor blockers are being developed which have a positive effect on maintaining the health of RPE. Conclusion A complex molecular association exists between the structural changes in ELM, EZ, and RPE in DR. SD-OCT is an indispensable tool to study these changes as integrity of these outer layers of retina is essential for maintaining visual function of retina in DR.http://www.thieme-connect.de/DOI/DOI?10.1055/s-0042-1742585diabetic retinopathyellipsoid zoneexternal limiting membraneretinal pigment epitheliumspectral domain optical coherence tomography |
| spellingShingle | Nibha Mishra Gurkiran Kaur Sandeep Saxena External Limiting Membrane, Photoreceptor Ellipsoid Zone Disruption, and Retinal Pigment Epithelium Alterations in Diabetic Retinopathy Annals of the National Academy of Medical Sciences (India) diabetic retinopathy ellipsoid zone external limiting membrane retinal pigment epithelium spectral domain optical coherence tomography |
| title | External Limiting Membrane, Photoreceptor Ellipsoid Zone Disruption, and Retinal Pigment Epithelium Alterations in Diabetic Retinopathy |
| title_full | External Limiting Membrane, Photoreceptor Ellipsoid Zone Disruption, and Retinal Pigment Epithelium Alterations in Diabetic Retinopathy |
| title_fullStr | External Limiting Membrane, Photoreceptor Ellipsoid Zone Disruption, and Retinal Pigment Epithelium Alterations in Diabetic Retinopathy |
| title_full_unstemmed | External Limiting Membrane, Photoreceptor Ellipsoid Zone Disruption, and Retinal Pigment Epithelium Alterations in Diabetic Retinopathy |
| title_short | External Limiting Membrane, Photoreceptor Ellipsoid Zone Disruption, and Retinal Pigment Epithelium Alterations in Diabetic Retinopathy |
| title_sort | external limiting membrane photoreceptor ellipsoid zone disruption and retinal pigment epithelium alterations in diabetic retinopathy |
| topic | diabetic retinopathy ellipsoid zone external limiting membrane retinal pigment epithelium spectral domain optical coherence tomography |
| url | http://www.thieme-connect.de/DOI/DOI?10.1055/s-0042-1742585 |
| work_keys_str_mv | AT nibhamishra externallimitingmembranephotoreceptorellipsoidzonedisruptionandretinalpigmentepitheliumalterationsindiabeticretinopathy AT gurkirankaur externallimitingmembranephotoreceptorellipsoidzonedisruptionandretinalpigmentepitheliumalterationsindiabeticretinopathy AT sandeepsaxena externallimitingmembranephotoreceptorellipsoidzonedisruptionandretinalpigmentepitheliumalterationsindiabeticretinopathy |