Xiaokun Wang1, Shoumyo Majumdar2, Garret Ma3, Jeeyeon Sohn3, Samuel C Yiu4, Walter Stark4, Awad Al-Qarni5, Deepak P Edward6, Jennifer H Elisseeff7. 1. Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States 2Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, Maryland, United States. 2. Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, Maryland, United States 3Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, United States. 3. Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States. 4. Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States. 5. Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. 6. Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States 5Ophthalmology, King Khaled Eye Specialist Hospital, Riyadh, Saudi Arabia. 7. Wilmer Eye Institute, Johns Hopkins School of Medicine, Baltimore, Maryland, United States 2Translational Tissue Engineering Center, Johns Hopkins University, Baltimore, Maryland, United States 3Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, Maryland, United States 4Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland, United States.
Abstract
Purpose: To evaluate the crosslinking effect of functionalized chondroitin sulfate (CS) in an ex vivo rabbit cornea model. Methods: Chondroitin sulfate molecules were chemically modified with the N-hydroxysuccinimide (NHS) group. Enucleated rabbit eyes were crosslinked with 2, 5, or 10 mg/mL CS-NHS solution for 30 or 60 minutes. The CS-NHS penetration, corneal swelling ratio, Young's modulus, and ultrastructure of the crosslinked corneas were characterized. In addition, rabbit corneas were further treated with a collagenase-chondroitinase solution to create an ex vivo keratoconus (KC)-like model. The KC model corneas were crosslinked with a standard riboflavin-ultraviolet (UV) method or alternatively with CS-NHS. Corneal mechanics, ultrastructure, and keratocyte gene expression were evaluated after UV and CS-NHS crosslinking. Results: CS-NHS effectively penetrated into the corneal stroma within 60 minutes of treatment initiation. CS-NHS crosslinking reduced the swelling ratio by 35%, increased Young's modulus by 20%, and increased collagen fibril diameter and density. CS-NHS crosslinking improved corneal mechanics of KC model corneas to levels comparable to those with UV crosslinking. Moreover, CS-NHS crosslinking demonstrated significant downregulation of proinflammatory gene expression of keratocytes, indicating a potential protective effect imparted by CS-NHS during crosslinking. Conclusions: Our results demonstrated that CS-NHS can reinforce normal and KC model corneal mechanics, and restore collagen density and alignment in KC model corneas without causing extensive keratocyte apoptosis and proinflammatory gene upregulation. Therefore, CS-NHS crosslinking can potentially provide an effective, safe, and biocompatible means of corneal reinforcement.
Purpose: To evaluate the crosslinking effect of functionalized chondroitin sulfate (CS) in an ex vivo rabbit cornea model. Methods:Chondroitin sulfate molecules were chemically modified with the N-hydroxysuccinimide (NHS) group. Enucleated rabbit eyes were crosslinked with 2, 5, or 10 mg/mL CS-NHS solution for 30 or 60 minutes. The CS-NHS penetration, corneal swelling ratio, Young's modulus, and ultrastructure of the crosslinked corneas were characterized. In addition, rabbit corneas were further treated with a collagenase-chondroitinase solution to create an ex vivo keratoconus (KC)-like model. The KC model corneas were crosslinked with a standard riboflavin-ultraviolet (UV) method or alternatively with CS-NHS. Corneal mechanics, ultrastructure, and keratocyte gene expression were evaluated after UV and CS-NHS crosslinking. Results:CS-NHS effectively penetrated into the corneal stroma within 60 minutes of treatment initiation. CS-NHS crosslinking reduced the swelling ratio by 35%, increased Young's modulus by 20%, and increased collagen fibril diameter and density. CS-NHS crosslinking improved corneal mechanics of KC model corneas to levels comparable to those with UV crosslinking. Moreover, CS-NHS crosslinking demonstrated significant downregulation of proinflammatory gene expression of keratocytes, indicating a potential protective effect imparted by CS-NHS during crosslinking. Conclusions: Our results demonstrated that CS-NHS can reinforce normal and KC model corneal mechanics, and restore collagen density and alignment in KC model corneas without causing extensive keratocyte apoptosis and proinflammatory gene upregulation. Therefore, CS-NHS crosslinking can potentially provide an effective, safe, and biocompatible means of corneal reinforcement.
Authors: Soohyun Kim; Iman Jalilian; Sara M Thomasy; Morgan A W Bowman; Vijay Krishna Raghunathan; Yeonju Song; Cynthia A Reinhart-King; Christopher J Murphy Journal: Transl Vis Sci Technol Date: 2020-05-21 Impact factor: 3.283