Expression and Impact of Fibronectin, Tenascin-C, Osteopontin, and Type XIV Collagen in Fuchs Endothelial Corneal Dystrophy.

Purpose: Fuchs endothelial corneal dystrophy (FECD) is characterized by Descemet's membrane (DM) abnormalities, namely an increased thickness and a progressive appearance of guttae and fibrillar membranes. The goal of this study was to identify abnormal extracellular matrix (ECM) proteins expressed in FECD DMs and to evaluate their impact on cell adhesion and migration. Methods: Gene expression profiles from in vitro (GSE112039) and ex vivo (GSE74123) healthy and FECD corneal endothelial cells were analyzed to identify deregulated matrisome genes. Healthy and end-stage FECD DMs were fixed and analyzed for guttae size and height. Immunostaining of fibronectin, tenascin-C, osteopontin, and type XIV collagen was performed on ex vivo specimens, as well as on tissue-engineered corneal endothelium reconstructed using healthy and FECD cells. An analysis of ECM protein expression according to guttae and fibrillar membrane was performed using immunofluorescent staining and phase contrast microscopy. Finally, cell adhesion was evaluated on fibronectin, tenascin-C, and osteopontin, and cell migration was studied on fibronectin and tenascin-C. Results: SPP1 (osteopontin), FN1 (fibronectin), and TNC (tenascin-C) genes were upregulated in FECD ex vivo cells, and SSP1 was upregulated in both in vitro and ex vivo FECD conditions. Osteopontin, fibronectin, tenascin-C, and type XIV collagen were expressed in FECD specimens, with differences in their location. Corneal endothelial cell adhesion was not significantly affected by fibronectin or tenascin-C but was decreased by osteopontin. The combination of fibronectin and tenascin-C significantly increased cell migration. Conclusions: This study highlights new abnormal ECM components in FECD, suggests a certain chronology in their deposition, and demonstrates their impact on cell behavior.

Intracameral Fibrinous Reaction During Descemet's Membrane Endothelial Keratoplasty.

PURPOSE: To determine the outcomes and predisposing factors of Descemet's membrane endothelial keratoplasty (DMEK) complicated by intraoperative fibrinous reaction. METHODS: Retrospective cohort study of 346 DMEKs. Medical charts were reviewed for recipient demographics, surgical indications, donor characteristics, and potential predisposing ocular and systemic factors. For DMEKs complicated by fibrin, surgeons' notes on events leading to fibrin formation and on its intraoperative management, occurrence of graft detachment, primary failure, re-bubbling or regrafting, time to graft clearing, and endothelial cell density were additionally collected. RESULTS: Fifteen (4.3%) DMEKs were complicated by fibrin, which interfered with and protracted graft unfolding in all cases. Median surgical time was longer than for uncomplicated DMEKs (p = 0.001). Graft positioning at the end of surgery was suboptimal in seven eyes (47%) and failed in three (20%). Re-bubbling, primary failure, and regraft rates were of 40%, 33% and 53%, respectively. The corneas that cleared did so in three to eight weeks, with median endothelial cell loss of 53% at 12 months. Use of anticoagulants was a preoperative risk factor (p = 0.01). Surgeon-identified intraoperative factors included beginner surgeons (87%), prolonged AC shallowing (47%) and graft manipulations (33%), intraocular bleeding (27%), new injector (20%), tight donor scroll (13%), and floppy iris (13%). CONCLUSION: Fibrinous reaction is a rare intraoperative complication of DMEK that interferes with graft unfolding and results in poor outcomes. Anticoagulant use appears to be a risk factor and may be compounded by surgical trauma to vascular tissues and prolonged surgical maneuvers.