Acceleration of Regeneration of the Corneal Endothelial Layer After Descemet Stripping Induced by the Engineered FGF TTHX1114 in Human Corneas in Organ Culture.

PURPOSE: Descemet stripping only (DSO, descemetorhexis without endothelial keratoplasty) is increasing in clinical use but can impose long recovery times. The objective of this research was to determine whether TTHX1114, an engineered analog of FGF1, could accelerate healing in corneas after DSO. METHODS: Corneas obtained from eye banks were placed into suspension culture and subjected to DSO with a procedure comparable with that used clinically. The healing of the stripped area and the regeneration of the corneal endothelial cell (CEC) layer were evaluated intermittently for 14 days using trypan blue staining, alizarin red staining, and immunohistochemistry. RESULTS: Corneas subjected to DSO showed about 30% of the stripped area healed after 14 days in culture while those treated with TTHX1114 healed 81%. The healed area was similar in both normal corneas and corneas judged by the eye banks to be dystrophic. The regeneration of the endothelial layer in the stripped area was substantially more complete in TTHX1114-treated corneas, most of which demonstrated a contiguous monolayer of CECs expressing ZO-1 at the cell-cell junctions. In corneas not subject to DSO, incorporation of EdU, a marker of proliferation, was stimulated by TTHX1114 treatment. CONCLUSIONS: The corneal organ culture model recapitulated clinical observations of DSO, only with much more rapid recovery. Within the immediate postsurgical time frame of 2 weeks, treatment with TTHX1114 stimulated near-total regeneration of the CEC layer, suggesting that TTHX1114 may be useful as an adjunct to DSO.

A Human Corneal Organ Culture Model of Descemet's Stripping Only with Accelerated Healing Stimulated by Engineered Fibroblast Growth Factor 1.

Fuchs Endothelial Corneal Dystrophy (FECD) results from dysfunctional corneal endothelial cells (CECs) and is currently treated by transplantation of the whole cornea or Descemet's membrane. Recent developments in ocular surgery have established Descemet's Stripping Only (DSO), a surgical technique in which a central circle of guttae-dense Descemet's membrane is removed to allow for the migration of CECs onto the smooth stroma, restoring function and vision to the cornea. While this potential treatment option is of high interest in the field of ophthalmic research, no successful ex vivo models of DSO have been established and clinical data is limited. This work presents a novel wound-healing model simulating DSO in human donor corneas. Using this approach to evaluate the efficacy of the human engineered FGF1 (NM141), we found that treatment accelerated healing via stimulation of migration and proliferation of CECs. This finding was confirmed in 11 pairs of human corneas with signs of dystrophy reported by the eye banks in order to verify that these results can be replicated in patients with Fuchs' Dystrophy, as the target population of the DSO procedure.

Proliferation of Human Corneal Endothelia in Organ Culture Stimulated by Wounding and the Engineered Human Fibroblast Growth Factor 1 Derivative TTHX1114.

Purpose: Corneal endothelial dystrophies are characterized by endothelial cell loss and dysfunction. Recent evidence suggests that corneal endothelial cells (CECs) can regenerate although they do not do so under normal conditions. This work sought to test whether CECs can be stimulated to proliferate in organ culture by wounding and/or by treatment with the engineered human fibroblast growth factor 1 (FGF1) derivative TTHX1114. Methods: Human donor corneas obtained from eye banks were maintained in organ culture in the presence or absence of TTHX1114. Wounds in the corneas were created by quartering the corneas. The CEC monolayer was identified as a regular layer by Hoechst staining of the nuclear DNA with cell outlines delineated by immunohistochemical identification of ZO-1. Nuclei and nuclei incorporating 5-ethynyl-2'-deoxyuridine (EdU) were counted using ImageJ. Results: CECs in normal corneas in undisturbed monolayers had low, but measurable, rates of proliferation. CECs at the edge of a wound had higher rates of proliferation, probably due to the release of contact inhibition. TTHX1114 increased proliferation at wound edges. After 7 days of culture, proliferating CECs formed contiguous groups of labeled cells that did not migrate away from one another. TTHX1114-treated cells, including the EdU labeled proliferating cells, retained normal morphology, including cell/cell junction ZO-1 staining. Conclusions: Proliferation of CECs in organ-cultured corneas is low, but can be stimulated by wounding or by the administration of TTHX1114 with the effects of each being additive. The CEC monolayer appears to have a population of progenitor cells that are susceptible to stimulation.