Feasibility of Descemet’s membrane removal during cultivated corneal endothelial cell injection in rabbit and monkey models

Abstract

Purpose: We developed a cultivated corneal endothelial cell (CEC) injection treatment for corneal endothelial dysfunction, and have now initiated clinical research. However, removal of pathologic Descemet’s membrane (DM) is thought to provide clinical benefits in cases of Fuchs' endothelial corneal dystrophy (FECD). Here we investigated the feasibility of DM removal during cultivated CEC-injection therapy in animal corneal endothelial dysfunction models.

Methods: Corneal endothelium was intensively scraped off in 12 eyes of 12 rabbits to create a corneal endothelial dysfunction model. A 5.0x10⁵ amount of rabbit CECs with rho-associated protein kinase (ROCK)-inhibitor Y-27632 was then injected into the anterior chamber of 4 eyes post DM removal (removal group) and into 4 eyes without DM removal (non-removal group), while 4 eyes without CEC injection were used as a control. In all eyes, slit-lamp examinations and corneal thickness- and intraocular pressure (IOP) measurements were performed for 14 days, followed by immunohistochemical analysis. As a preliminary experiment, a 5.0x10⁵ amount of cultured monkey CECs were injected in 1 eye of cynomolgus monkey corneal endothelial dysfunction model post DM removal.

Results: In the rabbit model, all control eyes failed to recover corneal clarity, while all eyes in the removal and non-removal groups recovered corneal clarity at 7-days postoperative. Corneal thickness was significantly thinner in the non-removal group than in the removal group at 2-days post-therapy (794.0±29.6μm and 1163.0±32.0μm, respectively; p<0.01), yet at 7-days post-therapy it had recovered to a similar thickness in both groups (615.3±54.5μm and 501.3±11.0μm, respectively). No eyes exhibited elevated IOP. Immunohistochemical analysis showed reconstruction of a homogeneous monolayer of polygonal cells expressing ZO-1, N-cadherin, and Na⁺/K⁺-ATPase in both the removal and non-removal groups. The monkey-model cornea became clear at 7-days post-therapy and immunohistochemical analysis showed regeneration of corneal endothelium expressing function-related proteins.

Conclusions: Our animal corneal endothelial dysfunction model findings indicate that CEC-injection and DM removal can reconstruct corneal endothelium. Further studies should provide a clinical protocol for CEC-injection therapy combined with DM removal to treat FECD.