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Sara M Thomasy, Vijaykrishna Raghunathan, Maryam Ali, Christopher J Murphy; Elastic modulus determination of Descemet’s membrane and endothelium in patients with and without guttata. Invest. Ophthalmol. Vis. Sci. 2016;57(12):5274.
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© ARVO (1962-2015); The Authors (2016-present)
Fuchs endothelial corneal dystrophy (FECD) is an endothelial degenerative disorder characterized by abnormal excrescences of extracellular matrix (ECM), termed guttata. While many attributes of the ECM in FECD have been well characterized, the alterations in the biophysical attributes of Descemet’s membrane (DM) and endothelium itself have not been adequately investigated. We hypothesized that the elastic modulus of DM and endothelium, a measure of stiffness, would increase in patients with guttata. The purpose of this study was to determine the elastic modulus of DM and endothelium in patients with and without guttata using atomic force microscopy (AFM).
Four human donor corneas were obtained and stored in Optisol storage medium until AFM could be performed. Patient signalment, disease status, endothelial cell density, and severity of guttata were recorded. The corneas were sectioned and elastic modulus measurement of DM and endothelium was performed. Histopathology was performed on adjacent corneal sections to confirm whether guttata were present or absent.
Patients included in the study were 3 male and 1 female Caucasians with an age range of 47 to 72 years. Two patients had no guttata with an appropriate endothelial cell density (2703 and 2950 cells/mm2) while two patients had moderate guttata with a decreased endothelial cell density (2252 and 1802 cells/mm2). All patients were phakic with an unremarkable anterior segment ocular history. Elastic modulus of DM was 20.7 and 22.9 kPa in the patients without guttata and 10.3 and 9.8 kPa in the patients with guttata. Elastic modulus of the endothelium was 0.77 and 0.61 kPa in the patients without guttata and 0.53 and 0.76 kPa in the patients with guttata. Histopathology of the corneal sections confirmed that patients were classified appropriately with regard to the presence or absence of guttata.
Elastic modulus of DM is dramatically decreased in patients with guttata. This change in stiffness of DM likely has a dramatic impact on endothelial cell behavior. Further studies of the impact of biophysical cues including substratum stiffness on the corneal endothelium are required.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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