Chondroitin sulfate–based biocompatible crosslinker restores corneal mechanics and collagen alignment

Xiaokun Wang, Shoumyo Majumdar, Garret Ma, Jeeyeon Sohn, Samuel Chi-Hung Yiu, Walter Stark, Awad Al Qarni, Deepak P. Edward, Jennifer Hartt Elisseeff

Research output: Contribution to journalArticle

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 expressionwere evaluated after UVand 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.

Original languageEnglish (US)
Pages (from-to)3887-3895
Number of pages9
JournalInvestigative Ophthalmology and Visual Science
Volume58
Issue number10
DOIs
StatePublished - 2017

Fingerprint

Chondroitin
Chondroitin Sulfates
Mechanics
Collagen
Keratoconus
Cornea
Elastic Modulus
Rabbits
N-hydroxysuccinimide
Corneal Stroma

Keywords

  • Chondroitin sulfate
  • Corneal biomechanics
  • Corneal crosslinking
  • Ultrastructure

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

Cite this

Chondroitin sulfate–based biocompatible crosslinker restores corneal mechanics and collagen alignment. / Wang, Xiaokun; Majumdar, Shoumyo; Ma, Garret; Sohn, Jeeyeon; Yiu, Samuel Chi-Hung; Stark, Walter; Qarni, Awad Al; Edward, Deepak P.; Elisseeff, Jennifer Hartt.

In: Investigative Ophthalmology and Visual Science, Vol. 58, No. 10, 2017, p. 3887-3895.

Research output: Contribution to journalArticle

Wang, Xiaokun ; Majumdar, Shoumyo ; Ma, Garret ; Sohn, Jeeyeon ; Yiu, Samuel Chi-Hung ; Stark, Walter ; Qarni, Awad Al ; Edward, Deepak P. ; Elisseeff, Jennifer Hartt. / Chondroitin sulfate–based biocompatible crosslinker restores corneal mechanics and collagen alignment. In: Investigative Ophthalmology and Visual Science. 2017 ; Vol. 58, No. 10. pp. 3887-3895.
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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 expressionwere evaluated after UVand 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.",
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T1 - Chondroitin sulfate–based biocompatible crosslinker restores corneal mechanics and collagen alignment

AU - Wang, Xiaokun

AU - Majumdar, Shoumyo

AU - Ma, Garret

AU - Sohn, Jeeyeon

AU - Yiu, Samuel Chi-Hung

AU - Stark, Walter

AU - Qarni, Awad Al

AU - Edward, Deepak P.

AU - Elisseeff, Jennifer Hartt

PY - 2017

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N2 - 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 expressionwere evaluated after UVand 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.

AB - 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 expressionwere evaluated after UVand 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.

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KW - Corneal crosslinking

KW - Ultrastructure

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