New evidences suggesting that the central endothelium of Fuchs Endothelial Corneal Dystrophy (FECD) presents features of peripheral endothelium

Purpose Most recent studies about FECD highlighted its complex and heterogeneous genetic background. Yet, the sequence of cellular mechanisms leading to the formation of Descemet excrescents (Guttae), endothelial cell (EC) death and loss of pumping functions remains poorly understood. Aim To present new phenotypic characteristics of ECs observed in late onset FCED, opening new perspectives in understanding its pathogenesis. Methods Thirty corneal central buttons were collected from FECD patients during graft. They were compared with fresh normal corneas (body donation to Sciences), and with 10 whole corneas with early stage of FECD (discarded from our eye bank). The morphology of ECs and of guttae, the expression of EC markers, of stem cell markers, of proliferation marker and of extracellular matrix was studied using the immunostaining of flat mount of corneas. Results Central ECs of FECD specimens and extreme peripheral ECs of fresh corneas shared common features: weaker expression of the usual CE markers (Na/K ATPase, ZO‐1, COXIV, CD166, N‐cadherin), expression of mesenchymal stem cells markers (nestin, c‐Myc, CD44), presence of proliferating cells (Ki67), presence of numerous dead cells (Ethidium), numerous cells containing pigments, isolated and confluent guttae, thicker Descemet membrane (DM), and localization of collagen I, IV, V and VIII. In corneas with early stages of FECD, the peripheral radial rows of EC and Descemet striae normally observed in healthy corneas were here significantly enlarged. Conclusions These new features of ECs and DM suggest that central ECs of FECD acquire or retain characteristics of peripheral ECs of healthy corneas, corresponding to less differentiated cells. We, therefore, suggest a new physiopathology mechanism involving the abnormal dedifferentiation of ECs in the centre of the cornea, resulting in the slow formation of the plaque‐like endothelial structure, typical of FCED.