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Direct measurements of collagen fiber recruitment in the posterior pole of the eye

Collagen is the main load-bearing component of the peripapillary sclera (PPS) and lamina cribrosa (LC) in the eye. Whilst it has been shown that uncrimping and recruitment of the PPS and LC collagen fibers underlies the macro-scale nonlinear stiffening of both tissues with increased intraocular pres...

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Autores principales: Lee, Po-Yi, Fryc, Gosia, Gnalian, John, Hua, Yi, Waxman, Susannah, Zhong, Fuqiang, Yang, Bin, Sigal, Ian A
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Cold Spring Harbor Laboratory 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10197604/
https://www.ncbi.nlm.nih.gov/pubmed/37215028
http://dx.doi.org/10.1101/2023.05.07.539784
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author Lee, Po-Yi
Fryc, Gosia
Gnalian, John
Hua, Yi
Waxman, Susannah
Zhong, Fuqiang
Yang, Bin
Sigal, Ian A
author_facet Lee, Po-Yi
Fryc, Gosia
Gnalian, John
Hua, Yi
Waxman, Susannah
Zhong, Fuqiang
Yang, Bin
Sigal, Ian A
author_sort Lee, Po-Yi
collection PubMed
description Collagen is the main load-bearing component of the peripapillary sclera (PPS) and lamina cribrosa (LC) in the eye. Whilst it has been shown that uncrimping and recruitment of the PPS and LC collagen fibers underlies the macro-scale nonlinear stiffening of both tissues with increased intraocular pressure (IOP), the uncrimping and recruitment as a function of local stretch have not been directly measured. This knowledge is crucial for the development of constitutive models associating micro and macro scales. In this project we measured local stretch-induced collagen fiber bundle uncrimping and recruitment curves of the PPS and LC. Thin coronal samples of PPS and LC of sheep eyes were mounted and stretched biaxially quasi-statically using a custom system. At each step, we imaged the PPS and LC with instant polarized light microscopy and quantified pixel-level (1.5 μm/pixel) collagen fiber orientations. We used digital image correlation to measure the local stretch and quantified collagen crimp by the circular standard deviation of fiber orientations, or waviness. Local stretch-recruitment curves of PPS and LC approximated sigmoid functions. PPS recruited more fibers than the LC at the low levels of stretch. At 10% stretch the curves crossed with 75% bundles recruited. The PPS had higher uncrimping rate and waviness remaining after recruitment than the LC: 0.9° vs. 0.6° and 3.1° vs. 2.7°. Altogether our findings support describing fiber recruitment of both PPS and LC with sigmoid curves, with the PPS recruiting faster and at lower stretch than the LC, consistent with a stiffer tissue.
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spelling pubmed-101976042023-05-20 Direct measurements of collagen fiber recruitment in the posterior pole of the eye Lee, Po-Yi Fryc, Gosia Gnalian, John Hua, Yi Waxman, Susannah Zhong, Fuqiang Yang, Bin Sigal, Ian A bioRxiv Article Collagen is the main load-bearing component of the peripapillary sclera (PPS) and lamina cribrosa (LC) in the eye. Whilst it has been shown that uncrimping and recruitment of the PPS and LC collagen fibers underlies the macro-scale nonlinear stiffening of both tissues with increased intraocular pressure (IOP), the uncrimping and recruitment as a function of local stretch have not been directly measured. This knowledge is crucial for the development of constitutive models associating micro and macro scales. In this project we measured local stretch-induced collagen fiber bundle uncrimping and recruitment curves of the PPS and LC. Thin coronal samples of PPS and LC of sheep eyes were mounted and stretched biaxially quasi-statically using a custom system. At each step, we imaged the PPS and LC with instant polarized light microscopy and quantified pixel-level (1.5 μm/pixel) collagen fiber orientations. We used digital image correlation to measure the local stretch and quantified collagen crimp by the circular standard deviation of fiber orientations, or waviness. Local stretch-recruitment curves of PPS and LC approximated sigmoid functions. PPS recruited more fibers than the LC at the low levels of stretch. At 10% stretch the curves crossed with 75% bundles recruited. The PPS had higher uncrimping rate and waviness remaining after recruitment than the LC: 0.9° vs. 0.6° and 3.1° vs. 2.7°. Altogether our findings support describing fiber recruitment of both PPS and LC with sigmoid curves, with the PPS recruiting faster and at lower stretch than the LC, consistent with a stiffer tissue. Cold Spring Harbor Laboratory 2023-05-08 /pmc/articles/PMC10197604/ /pubmed/37215028 http://dx.doi.org/10.1101/2023.05.07.539784 Text en https://creativecommons.org/licenses/by-nc/4.0/This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/) , which allows reusers to distribute, remix, adapt, and build upon the material in any medium or format for noncommercial purposes only, and only so long as attribution is given to the creator.
spellingShingle Article
Lee, Po-Yi
Fryc, Gosia
Gnalian, John
Hua, Yi
Waxman, Susannah
Zhong, Fuqiang
Yang, Bin
Sigal, Ian A
Direct measurements of collagen fiber recruitment in the posterior pole of the eye
title Direct measurements of collagen fiber recruitment in the posterior pole of the eye
title_full Direct measurements of collagen fiber recruitment in the posterior pole of the eye
title_fullStr Direct measurements of collagen fiber recruitment in the posterior pole of the eye
title_full_unstemmed Direct measurements of collagen fiber recruitment in the posterior pole of the eye
title_short Direct measurements of collagen fiber recruitment in the posterior pole of the eye
title_sort direct measurements of collagen fiber recruitment in the posterior pole of the eye
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10197604/
https://www.ncbi.nlm.nih.gov/pubmed/37215028
http://dx.doi.org/10.1101/2023.05.07.539784
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