Immunohistochemistry and electron microscopy of early-onset Fuchs corneal dystrophy in three cases with the same L450W COL8A2 mutation

Cheng Zhang, W. Robert Bell, Olof H. Sundin, Zenaida De La Cruz, Walter J. Stark, W. Richard Green, John D Gottsch

Research output: Contribution to journalArticle

Abstract

Purpose: A rare, familial early-onset form of Fuchs corneal dystrophy (FCD) is caused by mutation in the COL8A2 gene. This study describes the aberrant pattern of distribution of collagen type VIII and basement membrane components in Descemet's membrane (DM) and endothelium of three individuals with the same L450W mutation that represent different stages of early-onset FCD. Methods: Immunohistochemical studies with bright field, fluorescence, and confocal microscopy characterized the pathology of sectioned corneal buttons with antibodies against COL8A1, COL8A2, COL4, laminin, and fibronectin. A portion of each was processed for electron microscopy. Results: Histologic examination of pathologic changes in case 1 demonstrated relative preservation of the endothelium, whereas in case 2 much of this layer was atrophic and in case 3 there was complete loss of the endothelium. DM also increased in thickness to 25 μm for case 1, to 31 μm for case 2, and to 38 μm for case 3. Case 1 was the only specimen to reveal shallow warts along the posterior surface of DM, whereas the most advanced specimen, case 3, showed evidence of earlier nodularity that had been buried by the accretion of further extracellular matrix material. The posterior aspect of DM in this specimen had the unusual property of lighter staining relative to the anterior region of DM, laid down earlier in life. Immunocytochemistry revealed increased expression and complex, sharply defined patterns of deposition of collagen VIII, collagen IV, laminin, and fibronectin. Ultrastructurally, the posterior nonbanded layer of DM was intermixed with banded collagen, and the posterior region of DM showed a high density of foci of spindle-shaped structures with intense-staining bands, spaced at ∼ 120 nm. Finally, ultrastructural studies of the endothelium in case 1 revealed unusual accumulation of swelling mitochondria. The endothelial cells also had large amounts of abnormal prominent rough endoplasmic reticulum. Type VIII collagen alpha 2 immunogold signal was associated with the highly granular ribosomes of the rough endoplasmic reticulum of these patients. Conclusions: Microscopic and electron microscopic examination revealed pathological changes in DM of L450W COL8A2 mutants that were consistent with several-fold increased growth of the extracellular matrix and progressive deposition and synthesis of extracellular material by endothelial cells. As with late-onset FCD, this is accompanied by attenuation and eventual loss of the endothelium itself. Whether the abnormal deposition of collagen, laminin, and fibronectin contributes to the dysfunction and death of the endothelium remains to be determined.

Original languageEnglish (US)
Pages (from-to)85-95
Number of pages11
JournalTransactions of the American Ophthalmological Society
Volume104
StatePublished - 2006

Fingerprint

Fuchs' Endothelial Dystrophy
Descemet Membrane
Electron Microscopy
Immunohistochemistry
Endothelium
Mutation
Collagen Type VIII
Laminin
Collagen
Fibronectins
Rough Endoplasmic Reticulum
Extracellular Matrix
Endothelial Cells
Staining and Labeling
Warts
Ribosomes
Fluorescence Microscopy
Basement Membrane
Confocal Microscopy
Mitochondria

ASJC Scopus subject areas

  • Ophthalmology

Cite this

Immunohistochemistry and electron microscopy of early-onset Fuchs corneal dystrophy in three cases with the same L450W COL8A2 mutation. / Zhang, Cheng; Bell, W. Robert; Sundin, Olof H.; De La Cruz, Zenaida; Stark, Walter J.; Green, W. Richard; Gottsch, John D.

In: Transactions of the American Ophthalmological Society, Vol. 104, 2006, p. 85-95.

Research output: Contribution to journalArticle

Zhang, Cheng ; Bell, W. Robert ; Sundin, Olof H. ; De La Cruz, Zenaida ; Stark, Walter J. ; Green, W. Richard ; Gottsch, John D. / Immunohistochemistry and electron microscopy of early-onset Fuchs corneal dystrophy in three cases with the same L450W COL8A2 mutation. In: Transactions of the American Ophthalmological Society. 2006 ; Vol. 104. pp. 85-95.
@article{1850f345b3f4497580f8739d8b4eee87,
title = "Immunohistochemistry and electron microscopy of early-onset Fuchs corneal dystrophy in three cases with the same L450W COL8A2 mutation",
abstract = "Purpose: A rare, familial early-onset form of Fuchs corneal dystrophy (FCD) is caused by mutation in the COL8A2 gene. This study describes the aberrant pattern of distribution of collagen type VIII and basement membrane components in Descemet's membrane (DM) and endothelium of three individuals with the same L450W mutation that represent different stages of early-onset FCD. Methods: Immunohistochemical studies with bright field, fluorescence, and confocal microscopy characterized the pathology of sectioned corneal buttons with antibodies against COL8A1, COL8A2, COL4, laminin, and fibronectin. A portion of each was processed for electron microscopy. Results: Histologic examination of pathologic changes in case 1 demonstrated relative preservation of the endothelium, whereas in case 2 much of this layer was atrophic and in case 3 there was complete loss of the endothelium. DM also increased in thickness to 25 μm for case 1, to 31 μm for case 2, and to 38 μm for case 3. Case 1 was the only specimen to reveal shallow warts along the posterior surface of DM, whereas the most advanced specimen, case 3, showed evidence of earlier nodularity that had been buried by the accretion of further extracellular matrix material. The posterior aspect of DM in this specimen had the unusual property of lighter staining relative to the anterior region of DM, laid down earlier in life. Immunocytochemistry revealed increased expression and complex, sharply defined patterns of deposition of collagen VIII, collagen IV, laminin, and fibronectin. Ultrastructurally, the posterior nonbanded layer of DM was intermixed with banded collagen, and the posterior region of DM showed a high density of foci of spindle-shaped structures with intense-staining bands, spaced at ∼ 120 nm. Finally, ultrastructural studies of the endothelium in case 1 revealed unusual accumulation of swelling mitochondria. The endothelial cells also had large amounts of abnormal prominent rough endoplasmic reticulum. Type VIII collagen alpha 2 immunogold signal was associated with the highly granular ribosomes of the rough endoplasmic reticulum of these patients. Conclusions: Microscopic and electron microscopic examination revealed pathological changes in DM of L450W COL8A2 mutants that were consistent with several-fold increased growth of the extracellular matrix and progressive deposition and synthesis of extracellular material by endothelial cells. As with late-onset FCD, this is accompanied by attenuation and eventual loss of the endothelium itself. Whether the abnormal deposition of collagen, laminin, and fibronectin contributes to the dysfunction and death of the endothelium remains to be determined.",
author = "Cheng Zhang and Bell, {W. Robert} and Sundin, {Olof H.} and {De La Cruz}, Zenaida and Stark, {Walter J.} and Green, {W. Richard} and Gottsch, {John D}",
year = "2006",
language = "English (US)",
volume = "104",
pages = "85--95",
journal = "Transactions of the American Ophthalmological Society",
issn = "0065-9533",
publisher = "American Ophthalmological Society",

}

TY - JOUR

T1 - Immunohistochemistry and electron microscopy of early-onset Fuchs corneal dystrophy in three cases with the same L450W COL8A2 mutation

AU - Zhang, Cheng

AU - Bell, W. Robert

AU - Sundin, Olof H.

AU - De La Cruz, Zenaida

AU - Stark, Walter J.

AU - Green, W. Richard

AU - Gottsch, John D

PY - 2006

Y1 - 2006

N2 - Purpose: A rare, familial early-onset form of Fuchs corneal dystrophy (FCD) is caused by mutation in the COL8A2 gene. This study describes the aberrant pattern of distribution of collagen type VIII and basement membrane components in Descemet's membrane (DM) and endothelium of three individuals with the same L450W mutation that represent different stages of early-onset FCD. Methods: Immunohistochemical studies with bright field, fluorescence, and confocal microscopy characterized the pathology of sectioned corneal buttons with antibodies against COL8A1, COL8A2, COL4, laminin, and fibronectin. A portion of each was processed for electron microscopy. Results: Histologic examination of pathologic changes in case 1 demonstrated relative preservation of the endothelium, whereas in case 2 much of this layer was atrophic and in case 3 there was complete loss of the endothelium. DM also increased in thickness to 25 μm for case 1, to 31 μm for case 2, and to 38 μm for case 3. Case 1 was the only specimen to reveal shallow warts along the posterior surface of DM, whereas the most advanced specimen, case 3, showed evidence of earlier nodularity that had been buried by the accretion of further extracellular matrix material. The posterior aspect of DM in this specimen had the unusual property of lighter staining relative to the anterior region of DM, laid down earlier in life. Immunocytochemistry revealed increased expression and complex, sharply defined patterns of deposition of collagen VIII, collagen IV, laminin, and fibronectin. Ultrastructurally, the posterior nonbanded layer of DM was intermixed with banded collagen, and the posterior region of DM showed a high density of foci of spindle-shaped structures with intense-staining bands, spaced at ∼ 120 nm. Finally, ultrastructural studies of the endothelium in case 1 revealed unusual accumulation of swelling mitochondria. The endothelial cells also had large amounts of abnormal prominent rough endoplasmic reticulum. Type VIII collagen alpha 2 immunogold signal was associated with the highly granular ribosomes of the rough endoplasmic reticulum of these patients. Conclusions: Microscopic and electron microscopic examination revealed pathological changes in DM of L450W COL8A2 mutants that were consistent with several-fold increased growth of the extracellular matrix and progressive deposition and synthesis of extracellular material by endothelial cells. As with late-onset FCD, this is accompanied by attenuation and eventual loss of the endothelium itself. Whether the abnormal deposition of collagen, laminin, and fibronectin contributes to the dysfunction and death of the endothelium remains to be determined.

AB - Purpose: A rare, familial early-onset form of Fuchs corneal dystrophy (FCD) is caused by mutation in the COL8A2 gene. This study describes the aberrant pattern of distribution of collagen type VIII and basement membrane components in Descemet's membrane (DM) and endothelium of three individuals with the same L450W mutation that represent different stages of early-onset FCD. Methods: Immunohistochemical studies with bright field, fluorescence, and confocal microscopy characterized the pathology of sectioned corneal buttons with antibodies against COL8A1, COL8A2, COL4, laminin, and fibronectin. A portion of each was processed for electron microscopy. Results: Histologic examination of pathologic changes in case 1 demonstrated relative preservation of the endothelium, whereas in case 2 much of this layer was atrophic and in case 3 there was complete loss of the endothelium. DM also increased in thickness to 25 μm for case 1, to 31 μm for case 2, and to 38 μm for case 3. Case 1 was the only specimen to reveal shallow warts along the posterior surface of DM, whereas the most advanced specimen, case 3, showed evidence of earlier nodularity that had been buried by the accretion of further extracellular matrix material. The posterior aspect of DM in this specimen had the unusual property of lighter staining relative to the anterior region of DM, laid down earlier in life. Immunocytochemistry revealed increased expression and complex, sharply defined patterns of deposition of collagen VIII, collagen IV, laminin, and fibronectin. Ultrastructurally, the posterior nonbanded layer of DM was intermixed with banded collagen, and the posterior region of DM showed a high density of foci of spindle-shaped structures with intense-staining bands, spaced at ∼ 120 nm. Finally, ultrastructural studies of the endothelium in case 1 revealed unusual accumulation of swelling mitochondria. The endothelial cells also had large amounts of abnormal prominent rough endoplasmic reticulum. Type VIII collagen alpha 2 immunogold signal was associated with the highly granular ribosomes of the rough endoplasmic reticulum of these patients. Conclusions: Microscopic and electron microscopic examination revealed pathological changes in DM of L450W COL8A2 mutants that were consistent with several-fold increased growth of the extracellular matrix and progressive deposition and synthesis of extracellular material by endothelial cells. As with late-onset FCD, this is accompanied by attenuation and eventual loss of the endothelium itself. Whether the abnormal deposition of collagen, laminin, and fibronectin contributes to the dysfunction and death of the endothelium remains to be determined.

UR - http://www.scopus.com/inward/record.url?scp=33947708852&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33947708852&partnerID=8YFLogxK

M3 - Article

VL - 104

SP - 85

EP - 95

JO - Transactions of the American Ophthalmological Society

JF - Transactions of the American Ophthalmological Society

SN - 0065-9533

ER -