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Keratocyte loss in corneal infection through apoptosis: a histologic study of 59 cases

BACKGROUND: Keratocyte loss by apoptosis following epithelial debridement is a well-recognized entity. In a study of corneal buttons obtained from patients of corneal ulcer undergoing therapeutic keratoplasty, we observed loss of keratocytes in the normal appearing corneal stroma, surrounding the zo...

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Autores principales: Vemuganti, Geeta K, Reddy, Kishore, Iftekhar, Ghazala, Garg, Prashant, Sharma, Savitri
Formato: Texto
Lenguaje:English
Publicado: BioMed Central 2004
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC545077/
https://www.ncbi.nlm.nih.gov/pubmed/15617577
http://dx.doi.org/10.1186/1471-2415-4-16
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author Vemuganti, Geeta K
Reddy, Kishore
Iftekhar, Ghazala
Garg, Prashant
Sharma, Savitri
author_facet Vemuganti, Geeta K
Reddy, Kishore
Iftekhar, Ghazala
Garg, Prashant
Sharma, Savitri
author_sort Vemuganti, Geeta K
collection PubMed
description BACKGROUND: Keratocyte loss by apoptosis following epithelial debridement is a well-recognized entity. In a study of corneal buttons obtained from patients of corneal ulcer undergoing therapeutic keratoplasty, we observed loss of keratocytes in the normal appearing corneal stroma, surrounding the zone of inflammation. Based on these observations, we hypothesized that the cell loss in the inflammatory free zone of corneal stroma is by apoptosis that could possibly be a non-specific host response, independent of the nature of infectious agent. METHODS: To test our hypothesis, in this study, we performed Terminal deoxyribonucleotidyl transferase-mediated d-Uridine 5" triphosphate Nick End Labelling (TUNEL) staining on 59 corneal buttons from patients diagnosed as bacterial, fungal, viral and Acanthamoeba keratitis. The corneal sections were reviewed for morphologic changes in the epithelium, stroma, type, degree and depth of inflammation, loss of keratocytes in the surrounding stroma (posterior or peripheral). TUNEL positivity was evaluated in the corneal sections, both in the zone of inflammation as well as the surrounding stroma. A correlation was attempted between the keratocyte loss, histologic, microbiologic and clinical features. RESULTS: The corneal tissues were from 59 patients aged between 16 years and 85 years (mean 46 years) and included fungal (22), viral (15), bacterial (14) and Acanthamoeba (8) keratitis. The morphological changes in corneal tissues noted were: epithelial ulceration (52, 88.1%), destruction of Bowman's layer (58, 99%), mild to moderate (28; 47.5%) to severe inflammation (31; 52.5%). Morphologic evidence of disappearance or reduced number of keratocytic nuclei in the corneal stroma was noted in 49 (83%) cases; while the TUNEL positive brown cells were identified in all cases 53/54 (98%), including cases of fungal (19), bacterial (14), viral (13), and Acanthamoeba keratitis. TUNEL staining was located mostly in the deeper stroma and in few cases the peripheral stroma. TUNEL positivity was also noted with the polymorphonuclear infiltrates and in few epithelial cells (10 of 59, 17%) cases, more with viral infections (6/10; 60%). CONCLUSIONS: We report apoptotic cell death of keratocytes in the corneal stroma in infectious keratitis, a phenomenon independent of type of infectious agent. The inflammatory cells in the zone of inflammation also show evidence of apoptotic cell death. It could be speculated that the infective process possibly triggers keratocyte loss of the surrounding stroma by apoptosis, which could possibly be a protective phenomenon. It also suggests that necrotic cell death and apoptotic cell deaths could occur simultaneously in infective conditions of the cornea.
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spelling pubmed-5450772005-01-23 Keratocyte loss in corneal infection through apoptosis: a histologic study of 59 cases Vemuganti, Geeta K Reddy, Kishore Iftekhar, Ghazala Garg, Prashant Sharma, Savitri BMC Ophthalmol Research Article BACKGROUND: Keratocyte loss by apoptosis following epithelial debridement is a well-recognized entity. In a study of corneal buttons obtained from patients of corneal ulcer undergoing therapeutic keratoplasty, we observed loss of keratocytes in the normal appearing corneal stroma, surrounding the zone of inflammation. Based on these observations, we hypothesized that the cell loss in the inflammatory free zone of corneal stroma is by apoptosis that could possibly be a non-specific host response, independent of the nature of infectious agent. METHODS: To test our hypothesis, in this study, we performed Terminal deoxyribonucleotidyl transferase-mediated d-Uridine 5" triphosphate Nick End Labelling (TUNEL) staining on 59 corneal buttons from patients diagnosed as bacterial, fungal, viral and Acanthamoeba keratitis. The corneal sections were reviewed for morphologic changes in the epithelium, stroma, type, degree and depth of inflammation, loss of keratocytes in the surrounding stroma (posterior or peripheral). TUNEL positivity was evaluated in the corneal sections, both in the zone of inflammation as well as the surrounding stroma. A correlation was attempted between the keratocyte loss, histologic, microbiologic and clinical features. RESULTS: The corneal tissues were from 59 patients aged between 16 years and 85 years (mean 46 years) and included fungal (22), viral (15), bacterial (14) and Acanthamoeba (8) keratitis. The morphological changes in corneal tissues noted were: epithelial ulceration (52, 88.1%), destruction of Bowman's layer (58, 99%), mild to moderate (28; 47.5%) to severe inflammation (31; 52.5%). Morphologic evidence of disappearance or reduced number of keratocytic nuclei in the corneal stroma was noted in 49 (83%) cases; while the TUNEL positive brown cells were identified in all cases 53/54 (98%), including cases of fungal (19), bacterial (14), viral (13), and Acanthamoeba keratitis. TUNEL staining was located mostly in the deeper stroma and in few cases the peripheral stroma. TUNEL positivity was also noted with the polymorphonuclear infiltrates and in few epithelial cells (10 of 59, 17%) cases, more with viral infections (6/10; 60%). CONCLUSIONS: We report apoptotic cell death of keratocytes in the corneal stroma in infectious keratitis, a phenomenon independent of type of infectious agent. The inflammatory cells in the zone of inflammation also show evidence of apoptotic cell death. It could be speculated that the infective process possibly triggers keratocyte loss of the surrounding stroma by apoptosis, which could possibly be a protective phenomenon. It also suggests that necrotic cell death and apoptotic cell deaths could occur simultaneously in infective conditions of the cornea. BioMed Central 2004-12-24 /pmc/articles/PMC545077/ /pubmed/15617577 http://dx.doi.org/10.1186/1471-2415-4-16 Text en Copyright © 2004 Vemuganti et al; licensee BioMed Central Ltd.
spellingShingle Research Article
Vemuganti, Geeta K
Reddy, Kishore
Iftekhar, Ghazala
Garg, Prashant
Sharma, Savitri
Keratocyte loss in corneal infection through apoptosis: a histologic study of 59 cases
title Keratocyte loss in corneal infection through apoptosis: a histologic study of 59 cases
title_full Keratocyte loss in corneal infection through apoptosis: a histologic study of 59 cases
title_fullStr Keratocyte loss in corneal infection through apoptosis: a histologic study of 59 cases
title_full_unstemmed Keratocyte loss in corneal infection through apoptosis: a histologic study of 59 cases
title_short Keratocyte loss in corneal infection through apoptosis: a histologic study of 59 cases
title_sort keratocyte loss in corneal infection through apoptosis: a histologic study of 59 cases
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC545077/
https://www.ncbi.nlm.nih.gov/pubmed/15617577
http://dx.doi.org/10.1186/1471-2415-4-16
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