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Protective Effects of Soluble Collagen during Ultraviolet-A Crosslinking on Enzyme-Mediated Corneal Ectatic Models.

Wang X, Huang Y, Jastaneiah S, Majumdar S, Kang JU, Yiu SC, Stark W, Elisseeff JH - PLoS ONE (2015)

Bottom Line: The models were then used to evaluate the protective effect of soluble collagen in the UVA crosslinking system.Enzyme treatments resulted in corneal curvature changes, collagen ultrastructural damage, decreased swelling resistance and thermal stability, which are similar to what is observed in keratoconus eyes.UVA crosslinking restored swelling resistance and thermal stability, but ultrastructural damage were found in the crosslinked ectatic corneas.

View Article: PubMed Central - PubMed

Affiliation: Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America.

ABSTRACT
Collagen crosslinking is a relatively new treatment for structural disorders of corneal ectasia, such as keratoconus. However, there is a lack of animal models of keratoconus, which has been an obstacle for carefully analyzing the mechanisms of crosslinking and evaluating new therapies. In this study, we treated rabbit eyes with collagenase and chondroitinase enzymes to generate ex vivo corneal ectatic models that simulate the structural disorder of keratoconus. The models were then used to evaluate the protective effect of soluble collagen in the UVA crosslinking system. After enzyme treatment, the eyes were exposed to riboflavin/UVA crosslinking with and without soluble type I collagen. Corneal morphology, collagen ultrastructure, and thermal stability were evaluated before and after crosslinking. Enzyme treatments resulted in corneal curvature changes, collagen ultrastructural damage, decreased swelling resistance and thermal stability, which are similar to what is observed in keratoconus eyes. UVA crosslinking restored swelling resistance and thermal stability, but ultrastructural damage were found in the crosslinked ectatic corneas. Adding soluble collagen during crosslinking provided ultrastructural protection and further enhanced the swelling resistance. Therefore, UVA crosslinking on the ectatic model mimicked typical clinical treatment for keratoconus, suggesting that this model replicates aspects of human keratoconus and could be used for investigating experimental therapies and treatments prior to translation.

No MeSH data available.


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Schematic of enzyme-mediated corneal ectatic model and UVA crosslinking(A) Corneal ectatic model created by collagenase or chondroitinase treatments. (B) UVA crosslinking process with RF and soluble collagen.
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pone.0136999.g001: Schematic of enzyme-mediated corneal ectatic model and UVA crosslinking(A) Corneal ectatic model created by collagenase or chondroitinase treatments. (B) UVA crosslinking process with RF and soluble collagen.

Mentions: The digesting solutions contained 20 U/ml collagenase type II (LS004177 Worthington, 280 U/mg) in PBS, and 0.1 U/ml chondroitinase ABC (C36675U Sigma Aldrich) in Tris buffer, with 50 mM Tris base, 60 mM sodium acetate, and 0.02% bovine serum albumin, pH 8.0. The surfaces of rabbit eyes were wiped with 70% ethanol 15 sec to loosen the epithelial layer. After epithelial removal, rabbit eyes were immersed in enzyme solutions and incubated at 37°C on the shaker at 400 rpm for 3 hours. The treatment was stopped by rinsing in DMEM/10% fetal bovine serum (Gibco) three times. The schematic of the treatment is shown in Fig 1A.


Protective Effects of Soluble Collagen during Ultraviolet-A Crosslinking on Enzyme-Mediated Corneal Ectatic Models.

Wang X, Huang Y, Jastaneiah S, Majumdar S, Kang JU, Yiu SC, Stark W, Elisseeff JH - PLoS ONE (2015)

Schematic of enzyme-mediated corneal ectatic model and UVA crosslinking(A) Corneal ectatic model created by collagenase or chondroitinase treatments. (B) UVA crosslinking process with RF and soluble collagen.
© Copyright Policy
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC4556688&req=5

pone.0136999.g001: Schematic of enzyme-mediated corneal ectatic model and UVA crosslinking(A) Corneal ectatic model created by collagenase or chondroitinase treatments. (B) UVA crosslinking process with RF and soluble collagen.
Mentions: The digesting solutions contained 20 U/ml collagenase type II (LS004177 Worthington, 280 U/mg) in PBS, and 0.1 U/ml chondroitinase ABC (C36675U Sigma Aldrich) in Tris buffer, with 50 mM Tris base, 60 mM sodium acetate, and 0.02% bovine serum albumin, pH 8.0. The surfaces of rabbit eyes were wiped with 70% ethanol 15 sec to loosen the epithelial layer. After epithelial removal, rabbit eyes were immersed in enzyme solutions and incubated at 37°C on the shaker at 400 rpm for 3 hours. The treatment was stopped by rinsing in DMEM/10% fetal bovine serum (Gibco) three times. The schematic of the treatment is shown in Fig 1A.

Bottom Line: The models were then used to evaluate the protective effect of soluble collagen in the UVA crosslinking system.Enzyme treatments resulted in corneal curvature changes, collagen ultrastructural damage, decreased swelling resistance and thermal stability, which are similar to what is observed in keratoconus eyes.UVA crosslinking restored swelling resistance and thermal stability, but ultrastructural damage were found in the crosslinked ectatic corneas.

View Article: PubMed Central - PubMed

Affiliation: Wilmer Eye Institute, School of Medicine, Johns Hopkins University, Baltimore, Maryland, United States of America.

ABSTRACT
Collagen crosslinking is a relatively new treatment for structural disorders of corneal ectasia, such as keratoconus. However, there is a lack of animal models of keratoconus, which has been an obstacle for carefully analyzing the mechanisms of crosslinking and evaluating new therapies. In this study, we treated rabbit eyes with collagenase and chondroitinase enzymes to generate ex vivo corneal ectatic models that simulate the structural disorder of keratoconus. The models were then used to evaluate the protective effect of soluble collagen in the UVA crosslinking system. After enzyme treatment, the eyes were exposed to riboflavin/UVA crosslinking with and without soluble type I collagen. Corneal morphology, collagen ultrastructure, and thermal stability were evaluated before and after crosslinking. Enzyme treatments resulted in corneal curvature changes, collagen ultrastructural damage, decreased swelling resistance and thermal stability, which are similar to what is observed in keratoconus eyes. UVA crosslinking restored swelling resistance and thermal stability, but ultrastructural damage were found in the crosslinked ectatic corneas. Adding soluble collagen during crosslinking provided ultrastructural protection and further enhanced the swelling resistance. Therefore, UVA crosslinking on the ectatic model mimicked typical clinical treatment for keratoconus, suggesting that this model replicates aspects of human keratoconus and could be used for investigating experimental therapies and treatments prior to translation.

No MeSH data available.


Related in: MedlinePlus