Myofibroblast Metaplasia After Descemet Membrane Endothelial Keratoplasty

doi:10.1016/j.ajo.2010.11.032

American Journal of Ophthalmology

Volume 151, Issue 6, June 2011, Pages 1019-1023.e2

https://doi.org/10.1016/j.ajo.2010.11.032 Get rights and content

Purpose

To describe myofibroblastic metaplasia of corneal endothelial cells in 2 cases with impaired visual function despite complete graft adherence after Descemet membrane endothelial keratoplasty (DMEK).

Design

Interventional case series.

Methods

In 2 of 90 consecutive DMEK surgeries, the cornea failed to clear up to 6 months postoperatively despite complete graft attachment. After secondary penetrating keratoplasty, both corneal buttons were examined using histopathologic analysis and transmission electron microscopy.

Results

Light microscopy revealed distinct corneal endothelial cell attenuation with the presence of an abnormal posterior collagenous layer in both cases. Most of the remaining endothelial cells had an elongated fibroblast-like appearance with immunopositivity for α-smooth muscle actin indicative of myofibroblast metaplasia. Transmission electron microscopy showed a slightly thickened Descemet membrane with an abnormal posterior fibrillar collagenous layer and a myofibroblast-like transformation of the remaining endothelial cells. Descemet membrane grafts closely adjoined the collagen lamellae of the host corneal stroma similar to the Descemet membrane–stroma interface of a normal cornea.

Conclusion

Myofibroblastic metaplasia of attenuated corneal endothelial cells with formation of an abnormal posterior collagenous layer may contribute to an impaired visual function despite complete graft adherence after Descemet membrane endothelial keratoplasty (DMEK).

Section snippets

Methods

Ninety consecutive DMEK surgeries were performed over a period of 12 months starting in June 2009. While 85 grafts stayed clear with marked improvement of visual acuity, 5 grafts were classified as early graft failure. Descemet membrane was chronically detached and graft failure was attributed to this fact in 3 of the 5 patients, while slit-lamp optical coherence tomography (SL-OCT, Heidelberg Engineering, Lübeck, Germany) confirmed complete graft adherence in the 2 patients who are presented

Results

Light microscopy revealed distinct corneal endothelial cell attenuation. Mean endothelial cell count was 4.2 ± 0.8 cells (range, 3-5) and 5.0 ± 2.5 cells (range, 1-7) (normal range: >120 cells) measured in 8 consecutive high-power fields (magnification ×400) per slide in 5 consecutive serial sections (Figure 2, Left). Most of the remaining endothelial cells had an elongated fibroblast-like appearance (Figure 2, Top right). Immunostaining revealed the presence of α-smooth muscle actin (α-SMA)

Discussion

To date, little information exists to explain impaired function after posterior lamellar surgery in patients with clinically attached grafts. Our findings are consistent with histopathologic observations after failed DSAEK, indicating that endothelial cell loss might be a reason for persistent corneal edema and malfunction after surgery.7, 8, 9, 10 However, DMEK grafts can also fail in patients where a close to normal endothelial cell count was obtained by in vivo microscopy.⁵ This finding may

Ludwig M. Heindl, MD, is a staff member of the Department of Ophthalmology at the Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany. He graduated from the Erlangen Medical School in 2006 and received training in clinical ophthalmology with Professor Kruse and ophthalmic pathology with Professor Naumann. His research interests include applied pathology of the eye, in particular of the cornea as well as (peri-)ocular tumors.

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A method to confirm correct orientation of Descemet membrane during Descemet membrane endothelial keratoplasty
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Retrocorneal fibrous membrane after phacoemulsification in an eye with pseudoexfoliative glaucoma
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To report a case of a retrocorneal fibrous membrane and corneal decompensation following uncomplicated phacoemulsification in an eye with pseudoexfoliative glaucoma.
Case report and literature review.
A monocular 83-year-old female developed corneal decompensation 1 year after uncomplicated cataract extraction via phacoemulsification. She had a history of pseudoexfoliative glaucoma and had undergone 3 rounds of selective laser trabeculoplasty in the same eye 3 years prior. Given the resulting corneal edema, the patient underwent Descemet's membrane endothelial keratoplasty, at which time a retrocorneal fibrous membrane was identified. Peeling of the membrane was surgically challenging and resulted in an intraocular hemorrhage intraoperatively and a small iridodialysis because the membrane had extended over the angle and iris. Postoperatively, the cornea cleared well, and vision improved significantly. However, vision was ultimately limited by macular pathology. Pathologic examination demonstrated Descemet's membrane with an attached fibrocellular membrane. Immunostaining for smooth muscle actin was positive within the membrane compatible with a retrocorneal membrane. We also present a review of the literature on modern causes of retrocorneal fibrous membranes.
Retrocorneal fibrous membranes are encountered most commonly following corneal transplantation and may be surgically challenging to remove. We present the first case of a pathologically proven retrocorneal fibrous membrane following uncomplicated cataract surgery via phacoemulsification and selective laser trabeculoplasty.
The fibrinolytic system in the cornea: A key regulator of corneal wound healing and biological defense
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The cornea is a relatively unique tissue in the body in that it possesses specific features such as a lack of blood vessels that contribute to its transparency. The cornea is supplied with soluble blood components such as albumin, globulin, and fibrinogen as well as with nutrients, oxygen, and bioactive substances by diffusion from aqueous humor and limbal vessels as well as a result of its exposure to tear fluid. The healthy cornea is largely devoid of cellular components of blood such as polymorphonuclear leukocytes, monocytes-macrophages, and platelets. The location of the cornea at the ocular surface renders it susceptible to external insults, and its avascular nature necessitates the operation of healing and defense mechanisms in a manner independent of a direct blood supply. The fibrinolytic system, which was first recognized for its role in the degradation of fibrin clots in the vasculature, has also been found to contribute to various biological processes outside of blood vessels. Fibrinolytic factors thus play an important role in biological defense of the cornea. In this review, we address the function of the fibrinolytic system in corneal defense including wound healing and the inflammatory response.
Fibrillar Layer as a Marker for Areas of Pronounced Corneal Endothelial Cell Loss in Advanced Fuchs Endothelial Corneal Dystrophy
2021, American Journal of Ophthalmology
Citation Excerpt :
Although there was a lower CEC density in pseudophakic compared with phakic FECD eyes in our study, our investigations did not provide any evidence that cataract surgery affects the size of the FL. The location of deposits and expression of COL I, COL III, and COL IV in our study are compatible with previous descriptions of the FL in late-onset FECD corneas and suggest an endothelial or myofibroblast origin.15,16,24,25,29 Since structural and compositional changes in the FECD DM affect cell behavior and may cause pathology, a primary pathogenetic role of the FL deposits in terms of an ECM-related toxic microenvironment needs to be considered.23,30–32
We sought to assess the correlation of corneal endothelial cell (CEC) density to alterations of collagen composition of Descemet membrane (DM) in advanced Fuchs endothelial corneal dystrophy (FECD) and to image such changes by slit-lamp biomicroscopy in vivo.
Prospective, observational consecutive case series.
Fifty eyes (50 subjects) with advanced FECD were enrolled. After slit-lamp biomicroscopy and corneal Scheimpflug imaging, the Descemet endothelium complex (DEC) was retrieved during DM endothelial keratoplasty (DMEK) surgery. The expression of collagens I, III, and IV (COL I, COL III, and COL IV) and corresponding CEC density were analyzed by immunofluorescence flat mount-staining. Presence, diameter and surface area of collagen expression, and CEC density served as the main outcome measures.
Immunofluorescence staining revealed central coherent collagen positive areas (mean surface area = 10 mm² ± 6 mm²) corresponding to a fibrillar layer burying the guttae of DM in 84% (42/50) of DECs. CEC density overlying the fibrillar layer compared with the periphery was significantly reduced (−54.8%, P < .0001) with a steep decline of CEC density at its borders. Subgroup analysis revealed that the fibrillar layer may be imaged by slit-lamp biomicroscopy in vivo with significant positive correlation of mean maximum diameter detected by slit-lamp biomicroscopy (d_{SL max} = 4.1 mm ± 0.9 mm) and by immunofluorescence staining (d_{IF max} = 4.7 mm ± 1.1 mm; r = 0.76; P = .001).
A fibrillar layer with a clear geographic pattern marks areas of pronounced loss of CEC density in advanced FECD eyes and may be imaged by slit-lamp biomicroscopy in vivo.
Clinicopathologic Correlations of Retrocorneal Membranes Associated With Endothelial Corneal Graft Failure
2021, American Journal of Ophthalmology
Citation Excerpt :
In an interventional cases series, histopathologic analysis was performed on corneal buttons removed at the time of secondary PKP in 2 cases of primary graft failure after DMEK (PKP performed 6 months post DMEK). Hematoxylin-eosin staining revealed a retrocorneal membrane composed of collagen and elongated fibroblast-like cells, which was positive for α-SMA.11 A similar finding was described in a series of 11 eyes with fibrous retrocorneal membranes associated with perforating injury and ulceration studied by light and electron microscopy.
To provide clinicopathologic correlations for retrocorneal membranes associated with Descemet stripping automated endothelial keratoplasty (DSAEK) failure.
Retrospective case series.
The specimens and medical records of the patients diagnosed with clinically significant retrocorneal membranes associated with DSAEK failure at the Bascom Palmer Eye Institute or the University of Miami Veterans Hospital between October 2015 and March 2020 were reviewed for demographics, clinical presentation, comorbidities, and surgeries performed. Histopathologic analysis was performed on hematoxylin-eosin and periodic acid–Schiff sections. Immunohistochemical studies were performed for smooth muscle actin (α-SMA), pancytokeratin, and CK7. Immunofluorescence was performed for vimentin, N-cadherin, ROCK1, RhoA, ZEB1, and Snail.
A total of 7 patients (3 male and 4 female) were identified to have a clinically significant retrocorneal membranes at the time of graft failure. The average age at the time of first DSAEK was 70 years (range: 55-85 years). All patients were pseudophakic and had a glaucoma drainage device in place; 1 had a history of failed DSAEK. Ranging from 0 to 47 months after surgery, a variably thick retrocorneal fibrous membrane was observed, eventually leading to graft failure. Four patients underwent subsequent penetrating keratoplasty and 3 underwent repeat DSAEK. On histopathologic evaluation, a pigmented fibrocellular tissue was identified along the posterior margin of the corneas and DSAEK buttons in all cases. Further characterization with immunohistochemistry and immunofluorescence demonstrated membranes to be negative for pancytokeratin and positive for α-SMA, vimentin, CK7, N-cadherin, ZEB1, Snail, ROCK1, and RhoA.
Fibrocellular retrocorneal membrane proliferation may be associated with DSAEK failure in patients with previous glaucoma drainage device surgery. Our results demonstrate myofibroblastic differentiation and a lack of epithelial differentiation. Positivity for markers of an endothelial-to-mesenchymal transition indicates possible endothelial origin and could be the hallmark for future targeted pharmacotherapy.
Corneal fibroblasts: Function and markers
2020, Experimental Eye Research
Citation Excerpt :
Although myofibroblasts contribute to wound healing after injury by mediating tissue contraction, these cells may also give rise to tissue scarring or fibrosis by releasing large quantities of ECM including collagen, fibronectin, and proteoglycans (Funderburgh et al., 2003; Garana et al., 1992). Myofibroblasts are thus generated in the cornea in association with radial keratotomy incisions, late haze after photorefractive keratectomy, laser in situ keratomileusis, or Descemet's membrane endothelial keratoplasty (Heindl et al., 2011; Wilson, 2020), and they contribute to corneal stromal scarring or fibrosis that develops after alkali burns or infection and which can lead to vision loss (Saika et al., 2008). An understanding of the mechanisms underlying the appearance of myofibroblasts in the cornea may therefore help to prevent corneal scarring or fibrosis.
Corneal stromal keratocytes contribute to the maintenance of corneal transparency and shape by synthesizing and degrading extracellular matrix. They are quiescent in the healthy cornea, but they become activated in response to insults from the external environment that breach the corneal epithelium, with such activation being associated with phenotypic transformation into fibroblasts. Corneal fibroblasts (activated keratocytes) act as sentinel cells to sense various external stimuli—including damage-associated molecular patterns derived from injured cells, pathogen-associated molecular patterns of infectious microorganisms, and inflammatory mediators such as cytokines—under pathological conditions such as trauma, infection, and allergy. The expression of various chemokines and adhesion molecules by corneal fibroblasts determines the selective recruitment and activation of inflammatory cells in a manner dependent on the type of insult. In infectious keratitis, the interaction of corneal fibroblasts with various components of microbes and with cytokines derived from infiltrated inflammatory cells results in excessive degradation of stromal collagen and consequent corneal ulceration. Corneal fibroblasts distinguish between type 1 and type 2 inflammation through recognition of corresponding cytokines, with their activation by type 2 cytokines contributing to the pathogenesis of corneal lesions in severe ocular allergic diseases. Pharmacological targeting of corneal fibroblast function is thus a potential novel therapeutic approach to prevention of excessive corneal stromal inflammation, damage, and scarring.
Split cornea transplantation: Relationship between storage time of split donor tissue and outcome
2013, Ophthalmology
Citation Excerpt :
Longer storage of the posterior donor lenticule before actual use in DMEK surgery could be associated with a higher endothelial cell loss that potentially could persist, thereby degrading vision and increasing complications after posterior lamellar keratoplasty. However, the 1-year outcomes after DMEK using split donor tissue stored up to 1 week were well within the 1-year results reported by several groups for DMEK using nonstored tissue.18–35 The 1-year mean BSCVA of 20/25 was consistent with the 20/24 reported by Guerra et al.26 Similar excellent outcomes have also been reported by Dirisamer et al24 as well as by Laaser et al31 at 6 months after surgery.
To analyze the relationship between storage time of split donor tissue and outcomes after deep anterior lamellar keratoplasty (DALK) and Descemet's membrane endothelial keratoplasty (DMEK).
Retrospective analysis of a nonrandomized, consecutive, interventional case series.
One hundred ten eyes with anterior stromal disease suitable for DALK and 110 eyes with endothelial disease suitable for DMEK underwent surgically successful split cornea transplantation combining both procedures within 7 days after splitting.
Split donor storage times (splitting to grafting) and total storage times (death to grafting) were correlated with the 1-year functional and morphologic outcomes after DALK and DMEK surgery using a Spearman correlation coefficient and a Mann–Whitney U test.
Best spectacle-corrected visual acuity (BSCVA), endothelial cell density, and complication rates within 12 months of follow-up.
The mean split donor storage time was 35±47 hours (range, 0–162 hours) after splitting for anterior donor grafts and 21±40 hours (range, 0–158 hours) for posterior grafts. The mean total storage time was 352±108 hours (range, 108–678 hours) for anterior lamellas and 339±109 hours (range, 96–630 hours) for posterior lamellas. One year after DALK, the mean BSCVA was 20/30 (range, 20/50–20/20), endothelial cell loss was 8% (range, 2%–16%), and the complication rate (Descemet's folds, epitheliopathy, loose sutures) was 18%. One year after DMEK, the mean BSCVA was 20/25 (range, 20/40–20/16), endothelial cell loss was 41% (range, 17%–63%), and the complication rate (partial graft detachment) was 62%. For DALK and DMEK, no significant association was observed between split donor storage time as well as total storage time and BSCVA (P≥0.409), endothelial cell loss (P≥0.236), or complication rate (P≥0.647) within 1 year of follow-up.
Anterior and posterior donor tissue may be stored safely for up to 1 week in organ culture before use in DALK and DMEK surgery. This simplifies the clinical feasibility of split cornea transplantation to reduce donor shortage and cost in corneal transplantation in the future.
The author(s) have no proprietary or commercial interest in any materials discussed in this article.

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Friedrich E. Kruse, MD, is Professor and Chairman, Department of Ophthalmology at the Friedrich-Alexander University Erlangen-Nürnberg, Erlangen, Germany since 2004. After graduation from Heidelberg Medical School in 1984, he worked from 1988 to 1991 at the Bascom Palmer Eye Institute, Miami, Florida. His research interests include cellular and molecular biology of the ocular surface corneal transplantation and laser application.

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Original articleMyofibroblast Metaplasia After Descemet Membrane Endothelial Keratoplasty

Purpose

Design

Methods

Results

Conclusion

Section snippets

Methods

Results

Discussion

Ophthalmology

Ophthalmology

Ophthalmology

Ophthalmology

Am J Ophthalmol

Preliminary clinical results of Descemet membrane endothelial keratoplasty

Am J Ophthalmol

A method to confirm correct orientation of Descemet membrane during Descemet membrane endothelial keratoplasty

Am J Ophthalmol

Original article
Myofibroblast Metaplasia After Descemet Membrane Endothelial Keratoplasty