Crosslinking-Induced Corneal Endothelium Dysfunction and Its Protection by Topical Ripasudil Treatment

Xuemei Wang,Huping Wu,Minghui Liang,Zhirong Lin,Cheng Li,Yanlin Zhong,Wen-Qing Shi

doi:10.1155/2022/5179247

Abstract

Purpose To investigate the changes of corneal endothelium under different crosslinking conditions and the protective effect of ripasudil. Methods Corneal crosslinking groups were infiltrated with riboflavin and subsequently irradiated with 0.54 J/cm2 or 1.08 J/cm2 UVA, while noncrosslinking groups included neither UVA nor riboflavin treatment, only 1.08 J/cm2 UVA and only riboflavin treatment. Corneal opacity, variations in corneal endothelial cells, and corneal thickness of all groups were observed by slit lamp, in vivo confocal microscopy, and optical coherence tomography. Immunofluorescence staining and scanning electron microscopy were performed to evaluate changes in the structure and function of the corneal endothelium. The mice that received a corneal crosslinking dose of 1.08 J/cm2 were instilled with ripasudil to explore its protective effect on the corneal endothelium. Results Treatment with UVA and riboflavin caused an increase in corneal opacity and corneal thickness and decreased endothelial cell density. Furthermore, treatment with UVA and riboflavin caused endothelial cell DNA damage and destroyed the tight junction and pump function of the endothelium, while riboflavin or the same dose of UVA alone did not affect the endothelium. Ripasudil reduced DNA damage in endothelial cells, increased the density of cells, and protected the endothelium's integrity and function. Conclusion Riboflavin combined with UVA can damage the corneal endothelium's normal functioning. The corneal endothelium's wound healing is dose-dependent, and the ROCK inhibitor ripasudil maintains the endothelium's pump and barrier functions.

Highlights

Corneal crosslinking (CXL) therapy has been introduced as a minimally invasive treatment to prevent the development of keratectasia, which has completely changed the treatment of keratoconus and other corneal ectasias such as pellucid marginal degeneration and iatrogenic ectasia
In the U(+), R(+) group, corneal transparency was restored after 14 days, while the corneas remained edematous in the U(++), R(+) group (Figure 1(a))
Our study demonstrates that ROCK inhibition by ripasudil can reduce DNA damage, decrease the destruction of connections between endothelial cells, increase endothelial cell density, and protect the pump and barrier functions of the corneal endothelium

Summary

Introduction

Corneal crosslinking (CXL) therapy has been introduced as a minimally invasive treatment to prevent the development of keratectasia, which has completely changed the treatment of keratoconus and other corneal ectasias such as pellucid marginal degeneration and iatrogenic ectasia. CXL has been used in the treatment of other diseases, such as bullous keratopathy, infectious ulcers, ulcerative keratitis, and other causes of corneal edema [1]. The fundamentals of CXL and the molecular processes of photooxidative CXL are combined with riboflavin as a photosensitizer in this treatment. Riboflavin is nontoxic and can be used as a biological drug or a coloring agent in food processing [2]. Riboflavin serves both as a photosensitizer to promote corneal stiffening (crosslinking) by UVA and as a shield to reduce the level of UVA to below the cytotoxic threshold [5]

Methods

Results

Conclusion