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Hatami-Marbini H, Emu ME. Role of sulfated GAGs in shear mechanical properties of human and porcine cornea. Exp Eye Res 2025; 251:110181. [PMID: 39626838 DOI: 10.1016/j.exer.2024.110181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2024] [Revised: 10/18/2024] [Accepted: 11/21/2024] [Indexed: 12/11/2024]
Abstract
The corneal extracellular matrix is mainly composed of collagen fibers, proteoglycans (PGs), and glycosaminoglycans (GAGs). The present work was done to investigate the effect of GAGs on linear viscoelastic shear properties of human and porcine cornea. A clear understanding of structural functions of GAGs could result in the development of new intervention methods for diseased conditions that involve changes to the expression of GAGs/PGs. Here, we used keratanase II enzyme to deplete sulfated GAGs from porcine and human donor corneal disks. After quantifying the GAG content, collagen fiber diameter, and interfibrillar spacings of control and GAG-depleted specimens using the Blyscan assay and transmission electron microscopy, we performed torsional rheometry to determine their shear properties at different levels of axial strain. We found that the GAG content of control human (52.35 ± 3.40 μg/mg dry tissue) and porcine cornea (48.59 ± 7.79 μg/mg dry tissue) significantly reduced following keratanase II enzyme treatment. Moreover, we observed that the diameter of collagen fibers (28.78 ± 2.33 nm) and interfibrillar spacing (45.93 ± 2.33 nm) of human specimens were significantly smaller than the collagen fiber diameter (34.77 ± 21.90 nm) and interfibrillar spacing (54.28 ± 3.99 nm) of porcine corneal samples. Although GAG depletion did not have any significant effect on the collagen fiber diameter, it significantly increased the interfibrillar spacing in both porcine and human samples. Within the range of linear viscoelastic behavior, the shear stiffness of human and porcine corneal samples did not depend on the shear strain but significantly increased with increasing the applied axial strain. The average complex shear modulus was found to be between 1.0 KPa and 6.5 KPa and between 8.5 KPa and 31 KPa for control porcine and human corneal discs, respectively. The GAG removal caused significant reduction of shear stiffness in both human and porcine corneal samples. Based on these findings, we conclude that sulfated GAGs are important in defining shear properties of porcine and human corneas and significant GAG content variation adversely affects corneal shear modulus.
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Affiliation(s)
- Hamed Hatami-Marbini
- Mechanical and Industrial Engineering Department, University of Illinois Chicago, Chicago, IL, USA.
| | - Md Esharuzzaman Emu
- Mechanical and Industrial Engineering Department, University of Illinois Chicago, Chicago, IL, USA
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2
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Wu K, Li G, Gao J, Tian Y, Wei D, Wu C, Ding J, Zhu J, Luo H, Sun J, Ramakrishna S, Fan H. Glycerol Modulated Collagen Fibril Evolution and Lamellar Organization for Biomimetic Corneal Substitutes Construction. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2025; 21:e2407606. [PMID: 39686763 DOI: 10.1002/smll.202407606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2024] [Revised: 12/04/2024] [Indexed: 12/18/2024]
Abstract
Collagen as the main structural component of the cornea exhibits unique and highly organized fibril lamellae, which contribute to the maintenance of corneal structure and transparency. Nevertheless, collagen assembly in vitro to create ideal artificial corneal substitutes with human cornea comparable thickness and optics is still limited. Here, glycerol as a regulator can reconcile collagen thickness, transparency, and permeability, a conflicting goal by current keratoprosthesis strategies. Structure analysis reveals that glycerol treatment induces collagen hydrogels to undergo a sequential three-step multiscale structural evolution: weakened collagen crystallization at the molecular level, followed by ordered and distanced microfibril packaging at the nanoscale, and ultimately lamellar structure as well as fibril diameter and spacing-dependent optics at a macroscopic level. Such ultrastructure is then stabilized by oxazolidine crosslinking to obtain a collagen-based artificial corneal substitute (Col-Gly-OX) with optimal integration of optical clarity, mechanical robustness, high permeability, manufacturability, easy preservation and in vitro biocompatibility. Further in vivo study demonstrates that Col-Gly-OX displays excellent tissue integration, epithelialization, and stromal remodeling in a rabbit lamellar keratectomy. Overall, this work illustrates the potential of glycerol regulator to mediate the multiscale structural organization of collagen, providing a green, simple and effective strategy for the development of bionic artificial cornea.
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Affiliation(s)
- Kai Wu
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Gaowei Li
- Department of Neurosurgery, West China Hospital, West China School of Medicine, Sichuan University, Chengdu, China
| | - Jiaze Gao
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Yuan Tian
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Dan Wei
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Chengheng Wu
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
- Institute of Regulatory Science for Medical Devices, Sichuan University, Chengdu, 610065, China
| | - Jie Ding
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Jing Zhu
- Department of Ophthalmology, The Third People's Hospital of Chengdu, The Affiliated Hospital of Southwest Jiaotong University, Chengdu, 610031, China
| | - Hongrong Luo
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Jing Sun
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
| | - Seeram Ramakrishna
- Department of Mechanical Engineering, College of Design and Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore, 117575, Singapore
| | - Hongsong Fan
- National Engineering Research Center for Biomaterials, College of Biomedical Engineering, Sichuan University, Chengdu, Sichuan, 610065, China
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Basol M, Ersoz‐Gulseven E, Ozaktas H, Kalyoncu S, Utine CA, Cakan‐Akdogan G. Loss of carbohydrate sulfotransferase 6 function leads to macular corneal dystrophy phenotypes and skeletal defects in zebrafish. FEBS J 2025; 292:373-390. [PMID: 39642091 PMCID: PMC11734872 DOI: 10.1111/febs.17337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 07/14/2024] [Accepted: 11/19/2024] [Indexed: 12/08/2024]
Abstract
The carbohydrate sulfotransferase 6 (chst6) gene is linked to macular corneal dystrophy (MCD), a rare disease that leads to bilateral blindness due to the accumulation of opaque aggregates in the corneal stroma. chst6 encodes for a keratan sulfate proteoglycan (KSPG) specific sulfotransferase. MCD patients lose sulfated KSPGs (cKS) in the cornea and the serum. The significance of serum cKS loss has not been understood. Zebrafish cornea structure is similar to that of humans and it contains high levels of sulfated cKS in the stroma. Here, zebrafish chst6 is shown to be expressed in the cornea and head structures of the embryos. An animal model of MCD is developed by generating chst6 mutant animals with CRISPR/Cas9-mediated gene editing. The dramatic decrease in cKS epitopes in the mutants was shown with ELISA and immunofluorescence. Morphological defects or alterations of jaw cartilage were detected in a minor fraction of the mutant larvae. Loss of cKS epitopes and morphological defects was fully rescued with wild-type chst6. Mutant adult zebrafish displayed all clinical manifestations of MCD, while a fraction also displayed jaw and skeleton defects. Opaque accumulations formed in the eye, which were alcian blue positive. Loss of cKS in the corneal stroma and a decrease in corneal thickness were shown. Interestingly, alteration of transforming growth factor beta-induced (BIGH3) expression which was not described in patients was also observed. This is the first report of an MCD model in a genetically tractable organism, providing a preclinical model and insight into the importance of KSPG sulfation for proper skeletal morphogenesis.
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Affiliation(s)
- Merve Basol
- Izmir Biomedicine and Genome CenterTurkey
- Izmir International Biomedicine and Genome InstituteDokuz Eylül UniversityIzmirTurkey
| | | | - Helin Ozaktas
- Izmir Biomedicine and Genome CenterTurkey
- Izmir International Biomedicine and Genome InstituteDokuz Eylül UniversityIzmirTurkey
| | | | - Canan Asli Utine
- Izmir Biomedicine and Genome CenterTurkey
- Department of Ophthalmology, Faculty of MedicineDokuz Eylul UniversityIzmirTurkey
| | - Gulcin Cakan‐Akdogan
- Izmir Biomedicine and Genome CenterTurkey
- Department of Medical Biology, Faculty of MedicineDokuz Eylül UniversityIzmirTurkey
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Steijns JSJJ, Green D, Peeters LCW, Emans PJ, Boymans TA, Stassen RH, van den Akker GGH, Cremers A, Jutten LMC, Anderson JR, Peffers MJ, Caron MMJ, Welting TJM. Proteomic characterization of regenerated cartilage following knee joint distraction; a human case-study. Connect Tissue Res 2024; 65:486-496. [PMID: 39688003 DOI: 10.1080/03008207.2024.2440716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2024] [Revised: 12/03/2024] [Accepted: 12/06/2024] [Indexed: 12/18/2024]
Abstract
PURPOSE Knee joint distraction is a surgical procedure with cartilage-regenerating properties. The composition of joint distraction-regenerated cartilage in human patients is poorly documented. In this case-study, provided a unique opportunity to biomolecularly characterize the regenerated tissue from a patient who underwent bilateral distraction and later knee replacements. METHODS Knee joint distraction was conducted using an external fixation frame and total knee arthroplasty was performed several years later. Radiographic imaging was performed to assess the status of the knee joint prior, during and after clinical interventions. Following total knee replacement, cartilage biopsies were collected and processed for tissue sectioning and histochemical staining. Tandem mass-spectrometry proteomics analysis was used to characterize and compare the proteomic composition. RESULTS Both knee joints showed joint-space improvement pre- and post-knee joint distraction. Regenerated cartilage was white with an irregular surface, while native (lateral) cartilage had a yellow appearance and smooth surface. Histochemical staining showed higher Safranin-O positivity in native cartilage compared to regenerated cartilage, and differences in collagen structure. Proteomic analysis did not reveal major differences in cartilage extracellular matrix protein abundance. Bioinformatic analyses revealed enrichment in ribosomal proteins (regenerated cartilage) and RNA Polymerase II Transcription Termination (native cartilage). CONCLUSION Histologically, knee joint distraction-regenerated cartilage showed less glycosaminoglycans and disorganized collagen compared to native cartilage. However, mass-spectrometry has no major differences in extracellular matrix protein abundance, with proteomic clues suggesting protein translation regulation as a potential mechanism for regeneration.
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Affiliation(s)
- Jessica S J J Steijns
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
| | - Daniel Green
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Science, University of Liverpool, Liverpool, UK
| | - Laura C W Peeters
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
| | - Pieter J Emans
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
- Joint-Preserving Clinic, Department of Orthopedic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
- Center for Translational Mobility Research (CTMR), Department of Orthopaedic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Tim A Boymans
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
- Joint-Preserving Clinic, Department of Orthopedic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
- Center for Translational Mobility Research (CTMR), Department of Orthopaedic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Roderick H Stassen
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
| | - Guus G H van den Akker
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
| | - Andy Cremers
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
| | - Liesbeth M C Jutten
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
- Joint-Preserving Clinic, Department of Orthopedic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
- Center for Translational Mobility Research (CTMR), Department of Orthopaedic Surgery, Maastricht University Medical Center, Maastricht, The Netherlands
| | - James R Anderson
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Science, University of Liverpool, Liverpool, UK
| | - Mandy J Peffers
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Science, University of Liverpool, Liverpool, UK
| | - Marjolein M J Caron
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
| | - Tim J M Welting
- Laboratory for Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University, Maastricht, The Netherlands
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Hatami-Marbini H, Emu ME. The effect of enzymatic GAG degradation on transverse shear properties of porcine cornea. J Biomech 2024; 176:112360. [PMID: 39405836 DOI: 10.1016/j.jbiomech.2024.112360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2024] [Revised: 07/22/2024] [Accepted: 10/03/2024] [Indexed: 11/10/2024]
Abstract
The structural integrity of cornea depends on properties of its extracellular matrix, mainly a mixture of collagen fibers and soluble proteoglycans (PGs). PGs are macromolecules of negatively charged sulphated glycosaminoglycans (GAGs) covalently attached to a protein core. GAGs appear as bridges between adjacent collagen fibers and could facilitate force transfer between them. Furthermore, GAGs are responsible for corneal hydration by attracting and maintaining water molecules into the extracellular matrix. Based on these observations, GAGs are expected to be essential for biomechanical properties of cornea. The primary objective of the present study was to determine the effects of GAGs on shear properties of cornea. For this purpose, GAGs were enzymatically removed from porcine corneal disks by keratanase II enzyme. After confirming the successful removal of GAGs by histochemical methods, torsional rheometry was performed to characterize the shear stiffness of GAG-depleted samples as a function of axial strain. It was found that the shear modulus of all samples was a function of applied shear strain and compressive strain. Beyond the range of linear viscoelastic response, the average complex shear modulus decreased with increasing the shear strain. Increasing the axial strain from 0% to 40% significantly increased the average complex shear modulus of corneal disks in all groups. Finally, the enzyme treatment with keratanase II enzyme significantly decreased the shear stiffness. The experimental measurements were discussed in terms of microstructural and compositional properties of corneal extracellular matrix and it was concluded that GAGs play a significant role in defining shear properties of cornea.
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Affiliation(s)
- H Hatami-Marbini
- Mechanical and Industrial Engineering Department, University of Illinois Chicago, Chicago, IL, USA.
| | - M E Emu
- Mechanical and Industrial Engineering Department, University of Illinois Chicago, Chicago, IL, USA
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6
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Böl M, Leichsenring K, Kohn S, Ehret AE. The anisotropic and region-dependent mechanical response of wrap-around tendons under tensile, compressive and combined multiaxial loads. Acta Biomater 2024; 183:157-172. [PMID: 38838908 DOI: 10.1016/j.actbio.2024.05.053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 05/20/2024] [Accepted: 05/30/2024] [Indexed: 06/07/2024]
Abstract
The present work reports on the multiaxial region and orientation-dependent mechanical properties of two porcine wrap-around tendons under tensile, compressive and combined loads based on an extensive study with n=175 samples. The results provide a detailed dataset of the anisotropic tensile and compressive longitudinal properties and document a pronounced tension-compression asymmetry. Motivated by the physiological loading conditions of these tendons, which include transversal compression at bony abutments in addition to longitudinal tension, we systematically investigated the change in axial tension when the tendon is compressed transversally along one or both perpendicular directions. The results reveal that the transversal compression can increase axial tension (proximal-distal direction) in both cases to orders of 30%, yet by a larger amount in the first case (transversal compression in anterior-posterior direction), which seems to be more relevant for wrap-around tendons in-vivo. These quantitative measurements are in line with earlier findings on auxetic properties of tendon tissue, but show for the first time the influence of this property on the stress response of the tendon, and may thus reveal an important functional principle within these essential elements of force transmission in the body. STATEMENT OF SIGNIFICANCE: The work reports for the first time on multiaxial region and orientation-dependent mechanical properties of wrap-around tendons under various loads. The results indicate that differences in the mechanical properties exist between zones that are predominantly in a uniaxial tensile state and those that experience complex load states. The observed counterintuitive increase of the axial tension upon lateral compression points at auxetic properties of the tendon tissue which may be pivotal for the function of the tendon as an element of the musculoskeletal system. It suggests that the tendon's performance in transmitting forces is not diminished but enhanced when the action line is deflected by a bony pulley around which the tendon wraps, representing an important functional principle of tendon tissue.
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Affiliation(s)
- Markus Böl
- Institute of Mechanics and Adaptronics, Technische Universität Braunschweig, Braunschweig D-38106, Germany.
| | - Kay Leichsenring
- Institute of Mechanics and Adaptronics, Technische Universität Braunschweig, Braunschweig D-38106, Germany
| | - Stephan Kohn
- Institute of Mechanics and Adaptronics, Technische Universität Braunschweig, Braunschweig D-38106, Germany
| | - Alexander E Ehret
- Empa, Swiss Federal Laboratories for Materials Science and Technology, CH-8600 Dübendorf, Switzerland; Institute for Mechanical Systems, ETH Zurich, Zürich, CH-8092, Switzerland
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Segars KL, Trinkaus-Randall V. Glycosaminoglycans: Roles in wound healing, formation of corneal constructs and synthetic corneas. Ocul Surf 2023; 30:85-91. [PMID: 37657650 PMCID: PMC11059988 DOI: 10.1016/j.jtos.2023.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 07/31/2023] [Accepted: 08/29/2023] [Indexed: 09/03/2023]
Abstract
Maintaining the clarity of the cornea is essential for vision, and is achieved through an exquisite array of collagen fibrils and proteoglycans in the corneal stroma. Alterations in the identity and modifications of the glycosaminoglycans (GAGs) are seen both throughout the normal wound healing process and in pathological conditions resulting in corneal opacity. Understanding these changes has been essential for the development of corneal prostheses and corneal reconstruction. The goal of this review article is to summarize and consolidate research in the alterations seen in glycosaminoglycans in injured and hypoxic states, address the role of proteins that can regulate glycosaminoglycans in the corneal wound healing process, and apply these findings to the context of corneal restoration through reconstruction or the insertion of synthetic devices.
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Affiliation(s)
- Kristen L Segars
- Departments of Pharmacology, Physiology and Biophysics, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, 02118, USA
| | - Vickery Trinkaus-Randall
- Department of Biochemistry and Cell Biology, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, 02118, USA; Department of Ophthalmology, Boston University Chobanian and Avedisian School of Medicine, Boston, MA, 02118, USA.
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8
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Tinasi ALSN, Silveira CPB, Honsho CS, Laus JL, Aldrovani M. Birefringence analysis of collagen supraorganization in cat corneas with tropical keratopathy. Vet Ophthalmol 2023; 26:398-406. [PMID: 37335898 DOI: 10.1111/vop.13124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 04/02/2023] [Accepted: 06/10/2023] [Indexed: 06/21/2023]
Abstract
OBJECTIVE To evaluate the birefringent properties of the cornea and examine the supraorganizational aspects of collagen fibers in cats with tropical keratopathy. PROCEDURE In this study, 10-micrometer-thick sections of corneal tissue from cats with tropical keratopathy were examined, both in the opaque and transparent areas of the anterior stroma. Control samples were obtained from healthy cat corneas. Polarized light microscopy was employed to evaluate the birefringent properties using two distinct methods. The first method involved measuring the optical retardation associated with corneal birefringence, while the second method assessed the alignment/waviness of the birefringent collagen fibers. Differences were significant when p < .05. RESULTS Tropical keratopathy resulted in a significant rise (p < .05) in optical retardation in both opaque and transparent regions of the cat cornea. In the anterior stroma, both the opaque zones and transparent tissue exhibited a higher degree of collagen fiber packing than the control corneas. However, no significant differences (p > .05) in alignment were observed between the transparent tissue of the diseased cornea and the healthy corneas. CONCLUSION Supraorganizational changes in collagen fiber packing are not restricted to lesion zones in cat corneas affected by tropical keratopathy. Such alterations also occur in the corneal tissue of the anterior stroma adjoining the lesions. Therefore, it is plausible that the transparent tissue of the anterior stroma in corneas affected by the disease may have functional abnormalities, despite its macroscopic healthy appearance. Additional investigations are required to clarify the implications of these potential defects and their conceivable contribution to tropical keratopathy.
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9
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Hatami-Marbini H, Emu ME. The relationship between keratan sulfate glycosaminoglycan density and mechanical stiffening of CXL treatment. Exp Eye Res 2023; 234:109570. [PMID: 37454921 PMCID: PMC10530321 DOI: 10.1016/j.exer.2023.109570] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Revised: 06/20/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023]
Abstract
The corneal stroma is primarily composed of collagen fibrils, proteoglycans, and glycosaminoglycans (GAGs). It is known that corneal crosslinking (CXL) treatment improves mechanical properties of the cornea. However, the influence of stromal composition on the strengthening effect of CXL procedure has not been thoroughly investigated. The primary objective of the present research was to characterize the effect of keratan sulfate (KS) GAGs on the efficacy of CXL therapy. To this end, the CXL method was used to crosslink porcine corneal samples from which KS GAGs were enzymatically removed by keratanase II enzyme. Alcian blue staining was done to confirm the successful digestion of GAGs and uniaxial tensile experiments were performed for characterizing corneal mechanical properties. The influence of GAG removal and CXL treatment on resistance of corneal samples against enzymatic pepsin degradation was also quantified. It was found that removal of KS GAGs significantly softened corneal tensile properties (P < 0.05). Moreover, the CXL therapy significantly increased the tensile stiffness of GAG-depleted strips (P < 0.05). GAG-depleted corneal buttons were dissolved in the pepsin digestion solution significantly faster than control samples (P < 0.05). The CXL treatment significantly increased the time needed for complete pepsin digestion of GAG-depleted disks (P < 0.05). Based on these observations, we concluded that KS GAGs play a significant role in defining tensile properties and structural integrity of porcine cornea. Furthermore, the stiffening influence of the CXL treatment does not significantly depend on the density of corneal KS GAGs. The findings of the present study provided new information on the relation between corneal composition and CXL procedure mechanical effects.
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Affiliation(s)
- H Hatami-Marbini
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering, Department, University of Illinois Chicago, Chicago, IL, USA.
| | - Md E Emu
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering, Department, University of Illinois Chicago, Chicago, IL, USA
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10
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Tsui MC, Liu HY, Chu HS, Chen WL, Hu FR, Kao WWY, Wang IJ. The versatile roles of lumican in eye diseases: A review. Ocul Surf 2023; 29:388-397. [PMID: 37327869 DOI: 10.1016/j.jtos.2023.06.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/13/2023] [Accepted: 06/13/2023] [Indexed: 06/18/2023]
Abstract
Lumican is a keratan sulfate proteoglycan that belongs to the small leucine-rich proteoglycan family. Research has lifted the veil on the versatile roles of lumican in the pathogenesis of eye diseases. Lumican has pivotal roles in the maintenance of physiological tissue homogenesis and is often upregulated in pathological conditions, e.g., fibrosis, scar tissue formation in injured tissues, persistent inflammatory responses and immune anomaly, etc. Herein, we will review literature regarding the role of lumican in pathogenesis of inherited congenital and acquired eye diseases, e.g., cornea dystrophy, cataract, glaucoma and chorioretinal diseases, etc.
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Affiliation(s)
- Mei-Chi Tsui
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan; Department of Ophthalmology, An Nan Hospital, China Medical University, Tainan, Taiwan
| | - Hsin-Yu Liu
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan; Advanced Ocular Surface and Corneal Nerve Regeneration Center, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Hsiao-Sang Chu
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan; Advanced Ocular Surface and Corneal Nerve Regeneration Center, National Taiwan University Hospital, Taipei, Taiwan; Graduate Institute of Clinical Medicine, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Wei-Li Chen
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan; Advanced Ocular Surface and Corneal Nerve Regeneration Center, National Taiwan University Hospital, Taipei, Taiwan; Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Fung-Rong Hu
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan; Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Winston W-Y Kao
- Department of Ophthalmology, College of Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - I-Jong Wang
- Department of Ophthalmology, National Taiwan University Hospital, Taipei, Taiwan; Department of Ophthalmology, College of Medicine, National Taiwan University, Taipei, Taiwan.
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11
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Gesteira TF, Verma S, Coulson-Thomas VJ. Small leucine rich proteoglycans: Biology, function and their therapeutic potential in the ocular surface. Ocul Surf 2023; 29:521-536. [PMID: 37355022 PMCID: PMC11092928 DOI: 10.1016/j.jtos.2023.06.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 06/13/2023] [Accepted: 06/21/2023] [Indexed: 06/26/2023]
Abstract
Small leucine rich proteoglycans (SLRPs) are the largest family of proteoglycans, with 18 members that are subdivided into five classes. SLRPs are small in size and can be present in tissues as glycosylated and non-glycosylated proteins, and the most studied SLRPs include decorin, biglycan, lumican, keratocan and fibromodulin. SLRPs specifically bind to collagen fibrils, regulating collagen fibrillogenesis and the biomechanical properties of tissues, and are expressed at particularly high levels in fibrous tissues, such as the cornea. However, SLRPs are also very active components of the ECM, interacting with numerous growth factors, cytokines and cell surface receptors. Therefore, SLRPs regulate major cellular processes and have a central role in major fundamental biological processes, such as maintaining corneal homeostasis and transparency and regulating corneal wound healing. Over the years, mutations and/or altered expression of SLRPs have been associated with various corneal diseases, such as congenital stromal corneal dystrophy and cornea plana. Recently, there has been great interest in harnessing the various functions of SLRPs for therapeutic purposes. In this comprehensive review, we describe the structural features and the related functions of SLRPs, and how these affect the therapeutic potential of SLRPs, with special emphasis on the use of SLRPs for treating ocular surface pathologies.
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Affiliation(s)
| | - Sudhir Verma
- College of Optometry, University of Houston, USA; Department of Zoology, Deen Dayal Upadhyaya College, University of Delhi, Delhi, India
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12
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Hatami-Marbini H, Emu ME. The role of KS GAGs in the microstructure of CXL-treated corneal stroma; a transmission electron microscopy study. Exp Eye Res 2023; 231:109476. [PMID: 37068601 PMCID: PMC10826592 DOI: 10.1016/j.exer.2023.109476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/30/2023] [Accepted: 04/14/2023] [Indexed: 04/19/2023]
Abstract
The mechanical and physical properties of the cornea originate from the microstructure and composition of its extracellular matrix. It is known that collagen fibrils, with a relatively uniform diameter, are organized in a pseudo-hexagonal array. It has been suggested that proteoglycans and the interaction of their glycosaminoglycan (GAG) side chains with themselves and collagen fibrils are important for collagen fibril organization inside the cornea. There are several diseases such as keratoconus in which the regular collagen fibrillar packing becomes distorted causing corneal optical and mechanical properties to be compromised. The primary purpose of the present work was to investigate the role of GAGs on the microstructure of corneal extracellular matrix before and after corneal crosslinking (CXL) treatment. For this purpose, keratan sulphates (KS) were removed from corneal samples using the keratanase enzyme and the CXL procedure was used to crosslink the specimens. The transmission electron microscopy was then used to characterize the diameter of collagen fibrils and their interfibrillar spacing. It was found that KS GAG depletion increased the collagen interfibrillar spacing while the CXL treatment significantly decreased the interfibrillar spacing. The enzyme and CXL treatments had an insignificant effect on the diameter of collagen fibrils. The underlying mechanisms responsible for these observations were discussed in terms of the assumption that GAG chains form duplexes that behave as tiny ropes holding collagen fibrils in place.
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Affiliation(s)
- H Hatami-Marbini
- Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA.
| | - M E Emu
- Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA
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13
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Marzec E, Pięta P, Olszewski J. Dielectric properties of the non-glycated and in vitro methylglyoxal-glycated cornea of the rabbit eye. Bioelectrochemistry 2023; 150:108333. [PMID: 36463591 DOI: 10.1016/j.bioelechem.2022.108333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 11/21/2022] [Accepted: 11/27/2022] [Indexed: 12/02/2022]
Abstract
The dielectric properties of the non-glycated and in vitro methylglyoxal-glycated cornea of the rabbit eye were tested in the frequency range of 200 Hz to 100 kHz of the electric field and at temperatures of 25 to 140 °C. The denaturation temperature (Td) for the non-glycated cornea and the non-enzymatically glycated cornea are approximately 45 and 55 °C, respectively. The mechanism of proton conduction up to Td in a glycated cornea requires more energy, i.e. more than twice the activation energy (ΔH) than in non-glycated tissue. The dielectric spectra for both examined tissues showed the same characteristic frequency of about 7 kHz assigned to the orientation relaxation time of the polar side groups inside the corneal stroma. These results may be useful in the surgical treatment of the cornea using conductive keratoplasty and in tissue engineering for clinical applications to regenerate this tissue. The medical use of these physico-biological techniques is important because the human cornea protects all eye tissues from various environmental factors.
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Affiliation(s)
- E Marzec
- Department of Bionics and Experimental Medical Biology, Poznan University of Medical Sciences, Parkowa 2, 60-775 Poznań, Poland.
| | - P Pięta
- Department of Bionics and Experimental Medical Biology, Poznan University of Medical Sciences, Parkowa 2, 60-775 Poznań, Poland
| | - J Olszewski
- Department of Bionics and Experimental Medical Biology, Poznan University of Medical Sciences, Parkowa 2, 60-775 Poznań, Poland
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14
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Hashimoto A, Hirose T, Hashimoto K, Mizumoto S, Nitahara-Kasahara Y, Saka S, Yoshizawa T, Okada T, Yamada S, Kosho T, Watanabe T, Miyata S, Nomura Y. Collagen Network Formation in In Vitro Models of Musculocontractural Ehlers-Danlos Syndrome. Genes (Basel) 2023; 14:genes14020308. [PMID: 36833235 PMCID: PMC9957042 DOI: 10.3390/genes14020308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/05/2023] [Accepted: 01/18/2023] [Indexed: 01/26/2023] Open
Abstract
Loss-of-function mutations in carbohydrate sulfotransferase 14 (CHST14) cause musculocontractural Ehlers-Danlos syndrome-CHST14 (mcEDS-CHST14), characterized by multiple congenital malformations and progressive connective tissue fragility-related manifestations in the cutaneous, skeletal, cardiovascular, visceral and ocular system. The replacement of dermatan sulfate chains on decorin proteoglycan with chondroitin sulfate chains is proposed to lead to the disorganization of collagen networks in the skin. However, the pathogenic mechanisms of mcEDS-CHST14 are not fully understood, partly due to the lack of in vitro models of this disease. In the present study, we established in vitro models of fibroblast-mediated collagen network formation that recapacitate mcEDS-CHST14 pathology. Electron microscopy analysis of mcEDS-CHST14-mimicking collagen gels revealed an impaired fibrillar organization that resulted in weaker mechanical strength of the gels. The addition of decorin isolated from patients with mcEDS-CHST14 and Chst14-/- mice disturbed the assembly of collagen fibrils in vitro compared to control decorin. Our study may provide useful in vitro models of mcEDS-CHST14 to elucidate the pathomechanism of this disease.
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Affiliation(s)
- Ayana Hashimoto
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan
| | - Takuya Hirose
- Laboratory of Veterinary Anatomy, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu 069-8501, Hokkaido, Japan
| | - Kohei Hashimoto
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan
| | - Shuji Mizumoto
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya 468-8503, Aichi, Japan
| | - Yuko Nitahara-Kasahara
- Division of Molecular and Medical Genetics, Center for Gene and Cell Therapy, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Shota Saka
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan
| | - Takahiro Yoshizawa
- Division of Animal Research, Research Center for Advanced Science and Technology, Shinshu University, Matsumoto 390-8621, Nagano, Japan
| | - Takashi Okada
- Division of Molecular and Medical Genetics, Center for Gene and Cell Therapy, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Shuhei Yamada
- Department of Pathobiochemistry, Faculty of Pharmacy, Meijo University, Nagoya 468-8503, Aichi, Japan
| | - Tomoki Kosho
- Department of Medical Genetics, Shinshu University School of Medicine, Matsumoto 390-8621, Nagano, Japan
- Center for Medical Genetics, Shinshu University Hospital, Matsumoto 390-8621, Nagano, Japan
- Division of Clinical Sequencing, Shinshu University School of Medicine, Matsumoto 390-8621, Nagano, Japan
- Research Center for Supports to Advanced Science, Matsumoto 390-8621, Nagano, Japan
| | - Takafumi Watanabe
- Laboratory of Veterinary Anatomy, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu 069-8501, Hokkaido, Japan
| | - Shinji Miyata
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan
- Correspondence:
| | - Yoshihiro Nomura
- Graduate School of Agriculture, Tokyo University of Agriculture and Technology, 3-5-8 Saiwaicho, Fuchu, Tokyo 183-8509, Japan
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15
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Bains KK, Ashworth S, Koudouna E, Young RD, Hughes CE, Quantock AJ. Chondroitin Sulphate/Dermatan Sulphate Proteoglycans: Potential Regulators of Corneal Stem/Progenitor Cell Phenotype In Vitro. Int J Mol Sci 2023; 24:ijms24032095. [PMID: 36768414 PMCID: PMC9917298 DOI: 10.3390/ijms24032095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/13/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023] Open
Abstract
Chondroitin sulphate (CS) proteoglycans with variable sulphation-motifs along their glycosaminoglycan (GAG) chains are closely associated with the stem cell niche of articular cartilage, where they are believed to influence the characteristics of the resident stem cells. Here, we investigated the immunohistochemical distribution of hybrid CS/dermatan sulphate (DS) GAGs in the periphery of the adult chicken cornea, which is the location of the cornea's stem cell niche in a number of species, using a monoclonal antibody, 6C3, that recognises a sulphation motif-specific CS/DS GAG epitope. This revealed positive labelling that was restricted to the subepithelial corneal stroma, as well as nearby bony structures within the sclera, called ossicles. When cultivated on cell culture dishes coated with 6C3-rich CS/DS, corneal stromal cells (keratocytes) that had been isolated from embryonic chicken corneas formed circular colonies, which took several days to reach confluency. A flow cytometric analysis of these keratocytes revealed changes in their expression levels of the indicative stem cell markers, Connexin 43 (Cx43), Paired Box 6 (PAX6), B-lymphoma Moloney murine leukemia virus insertion region-1 (Bmi-1), and C-X-C Chemokine Receptor 4 (CXCR4) suggestive of a less-differentiated phenotype compared with expression levels in cells not exposed to CS/DS. These findings support the view that CS/DS promotes the retention of a stem cell phenotype in corneal cells, much as it has been proposed to do in other connective tissues.
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Affiliation(s)
- Kiranjit K. Bains
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
| | - Sean Ashworth
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
- School of Biosciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Elena Koudouna
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
- School of Biosciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Robert D. Young
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
| | - Clare E. Hughes
- School of Biosciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff CF10 3AX, UK
| | - Andrew J. Quantock
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Maindy Road, Cardiff CF24 4HQ, UK
- Correspondence:
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16
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Collagen-Based Biomimetic Systems to Study the Biophysical Tumour Microenvironment. Cancers (Basel) 2022; 14:cancers14235939. [PMID: 36497421 PMCID: PMC9739814 DOI: 10.3390/cancers14235939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/22/2022] [Accepted: 11/26/2022] [Indexed: 12/03/2022] Open
Abstract
The extracellular matrix (ECM) is a pericellular network of proteins and other molecules that provides mechanical support to organs and tissues. ECM biophysical properties such as topography, elasticity and porosity strongly influence cell proliferation, differentiation and migration. The cell's perception of the biophysical microenvironment (mechanosensing) leads to altered gene expression or contractility status (mechanotransduction). Mechanosensing and mechanotransduction have profound implications in both tissue homeostasis and cancer. Many solid tumours are surrounded by a dense and aberrant ECM that disturbs normal cell functions and makes certain areas of the tumour inaccessible to therapeutic drugs. Understanding the cell-ECM interplay may therefore lead to novel and more effective therapies. Controllable and reproducible cell culturing systems mimicking the ECM enable detailed investigation of mechanosensing and mechanotransduction pathways. Here, we discuss ECM biomimetic systems. Mainly focusing on collagen, we compare and contrast structural and molecular complexity as well as biophysical properties of simple 2D substrates, 3D fibrillar collagen gels, cell-derived matrices and complex decellularized organs. Finally, we emphasize how the integration of advanced methodologies and computational methods with collagen-based biomimetics will improve the design of novel therapies aimed at targeting the biophysical and mechanical features of the tumour ECM to increase therapy efficacy.
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17
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Quinlan RA, Clark JI. Insights into the biochemical and biophysical mechanisms mediating the longevity of the transparent optics of the eye lens. J Biol Chem 2022; 298:102537. [PMID: 36174677 PMCID: PMC9638808 DOI: 10.1016/j.jbc.2022.102537] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 09/20/2022] [Accepted: 09/22/2022] [Indexed: 11/18/2022] Open
Abstract
In the human eye, a transparent cornea and lens combine to form the "refracton" to focus images on the retina. This requires the refracton to have a high refractive index "n," mediated largely by extracellular collagen fibrils in the corneal stroma and the highly concentrated crystallin proteins in the cytoplasm of the lens fiber cells. Transparency is a result of short-range order in the spatial arrangement of corneal collagen fibrils and lens crystallins, generated in part by post-translational modifications (PTMs). However, while corneal collagen is remodeled continuously and replaced, lens crystallins are very long-lived and are not replaced and so accumulate PTMs over a lifetime. Eventually, a tipping point is reached when protein aggregation results in increased light scatter, inevitably leading to the iconic protein condensation-based disease, age-related cataract (ARC). Cataracts account for 50% of vision impairment worldwide, affecting far more people than other well-known protein aggregation-based diseases. However, because accumulation of crystallin PTMs begins before birth and long before ARC presents, we postulate that the lens protein PTMs contribute to a "cataractogenic load" that not only increases with age but also has protective effects on optical function by stabilizing lens crystallins until a tipping point is reached. In this review, we highlight decades of experimental findings that support the potential for PTMs to be protective during normal development. We hypothesize that ARC is preventable by protecting the biochemical and biophysical properties of lens proteins needed to maintain transparency, refraction, and optical function.
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Affiliation(s)
- Roy A Quinlan
- Department of Biosciences, Durham University, South Road Science Site, Durham, United Kingdom; Department of Biological Structure, University of Washington, Seattle, Washington, USA.
| | - John I Clark
- Department of Biological Structure, University of Washington, Seattle, Washington, USA.
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18
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Hatami-Marbini H, Emu ME. Effect of corneal collagen crosslinking on viscoelastic shear properties of the cornea. J Mech Behav Biomed Mater 2022; 133:105300. [PMID: 35749931 PMCID: PMC10826593 DOI: 10.1016/j.jmbbm.2022.105300] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/08/2022] [Accepted: 05/27/2022] [Indexed: 11/26/2022]
Abstract
The cornea is responsible for most of the refractive power in the eye and acts as a protective layer for internal contents of the eye. The cornea requires mechanical strength for maintaining its precise shape and for withstanding external and internal forces. Corneal collagen crosslinking (CXL) is a treatment option to improve corneal mechanical properties. The primary objective of this study was to characterize CXL effects on viscoelastic shear properties of the porcine cornea as a function of compressive strain. For this purpose, corneal buttons were prepared and divided into three groups: control group (n = 5), pseudo-crosslinked group (n = 5), and crosslinked group (n = 5). A rheometer was used to perform dynamics torsional shear experiments on corneal disks at different levels of compressive strain (0%-40%). Specifically, strain sweep experiments and frequency sweep tests were done in order to determine the range of linear viscoelasticity and frequency dependent shear properties, respectively. It was found that the shear properties of all samples were dependent on the shear strain magnitude, loading frequency, and compressive strain. With increasing the applied shear strain, all samples showed a nonlinear viscoelastic response. Furthermore, the shear modulus of samples increased with increasing the frequency of the applied shear strain and/or increasing the compressive strain. Finally, the CXL treatment significantly increased the shear storage and loss moduli when the compressive strain was varied from 0% to 30% (p < 0.05); larger shear moduli were observed at compressive 40% strain but the difference was not significant (P = 0.12).
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Affiliation(s)
- Hamed Hatami-Marbini
- Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA.
| | - Md Esharuzzaman Emu
- Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA
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19
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Hatami-Marbini H, Mehr JA. Modeling and experimental investigation of electromechanical properties of scleral tissue; a CEM model using an anisotropic hyperelastic constitutive relation. Biomech Model Mechanobiol 2022; 21:1325-1337. [PMID: 35962249 DOI: 10.1007/s10237-022-01590-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Accepted: 05/01/2022] [Indexed: 12/15/2022]
Abstract
The sclera is a soft tissue primarily consisting of collagen fibers, elastin, and proteoglycans. The proteoglycans are composed of a core protein and negatively charged glycosaminoglycan side chains. The fixed electric charges inside the scleral extracellular matrix play a key role in its swelling and are expected to cause the tissue to deform in response to an electric field. However, the electroactive response of the sclera has not yet been investigated. The present work experimentally demonstrates that sclera behaves similar to an anionic electrosensitive hydrogel and develops a chemo-electro-mechanical (CEM) mathematical framework for its electromechanical response. In the numerical model, a hyperelastic constitutive law with distributed collagen fibers is used to capture the nonlinear mechanical properties of the sclera, and the coupled Poisson-Nernst-Planck equations represent the distribution of mobile ions throughout the domain. After calibrating the proposed numerical CEM model against the experimental measurements, we employ it to investigate the effects of different parameters on the scleral electromechanical response including the voltage and fixed charge density. The experimental and numerical findings of the present study confirm that sclera behaves as an electroactive hydrogel and provide new insight into the mechanical response of this ocular tissue.
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Affiliation(s)
- Hamed Hatami-Marbini
- Mechanical and Industrial Engineering Department, University of Illinois at Chicago, 2039 Engineering Research Facility, 842 West Taylor St, Chicago, IL, 60607, USA.
| | - Jafar Arash Mehr
- Mechanical and Industrial Engineering Department, University of Illinois at Chicago, 2039 Engineering Research Facility, 842 West Taylor St, Chicago, IL, 60607, USA
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20
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Thermal-Induced Autolysis Enzymes Inactivation, Protein Degradation and Physical Properties of Sea Cucumber, Cucumaria frondosa. Processes (Basel) 2022. [DOI: 10.3390/pr10050847] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The main objective is to effectively denature the autolysis enzymes of C. frondosa on the premise of avoiding the quality deterioration caused by overheating. The effects of the different thermal treatments (blanching at 40–80 °C for 45 min, boiling and steaming at 100 °C for 15–120 min) on the cooking yield, moisture content, protein degradation, texture, and enzyme inactivation were studied, and the inner relationship was investigated by multivariate analysis. The autolysis enzymes of C. frondosa were thermally stable and cannot be denatured completely by blanching. Boiling and steaming could efficiently inactivate the enzymes but overheating for 60–120 min reduced the cooking yield and texture quality. Boiling at 100 °C for 45 min was suitable for pre-treatment, with cooking yield of 70.3% and protein content of 78.5%. Steaming at 100 °C for at least 30 min was preferable for long-term storage and instant food, in which the relative activity was only 3.2% with better palatability.
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21
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Mehr JA, Hatami-Marbini H. Experimental and numerical analysis of electroactive characteristics of scleral tissue. Acta Biomater 2022; 143:127-137. [PMID: 35038585 DOI: 10.1016/j.actbio.2022.01.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/04/2022] [Accepted: 01/10/2022] [Indexed: 11/15/2022]
Abstract
The sclera provides mechanical support to retina and protects internal contents of the eye against external injuries. The scleral extracellular matrix is mainly composed of collagen fibers and proteoglycans (PGs). At physiological pH, collagen molecules are neutral but PGs contain negatively charged glycosaminoglycan chains. Thus, the sclera can be considered as a polyelectrolyte hydrogel and is expected to exhibit mechanical response when subjected to electrical stimulations. In this study, we mounted scleral strips, dissected from the posterior part of porcine eyes, at the center of a custom-designed container between two electrodes. The container was filled with NaCl solution and the bending deformation of scleral strips as a function of the applied electric voltage was measured experimentally. It was found that scleral strips reached to an average bending angle of 3°, 10° and 23° when subjected to 5V, 10V, and 15V, respectively. We also created a chemo-electro-mechanical finite element model for simulating the experimental measurements by solving coupled Poisson-Nernst-Plank and equilibrium mechanical field equations. The scleral fixed charge density and modulus of elasticity were found by fitting the experimental data. The ion concentration distribution inside the domain was found numerically and was used to explain the underlying mechanisms for the scleral electroactive response. The numerical simulations were also used to investigate the effects of various parameters such as the electric voltage and fixed charge density on the scleral deformation under an electric field. STATEMENT OF SIGNIFICANCE: This manuscript investigates the electroactive response of scleral tissue. It demonstrates that the sclera deforms mechanically when subjected to electrical stimulations. A chemo-electro-mechanical model is also presented in order to numerically capture the electromechanical response of the sclera. This numerical model is used to explain the experimental observations by finding the ion distribution inside the tissue under an electric field. This work is significant because it shows that the sclera is an electroactive polyanionic hydrogel and it provides new information about the underlying mechanisms governing its mechanical and electrical properties.
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Affiliation(s)
- Jafar Arash Mehr
- Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL USA
| | - Hamed Hatami-Marbini
- Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL USA.
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22
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Tropocollagen springs allow collagen fibrils to stretch elastically. Acta Biomater 2022; 142:185-193. [PMID: 35081430 PMCID: PMC8982519 DOI: 10.1016/j.actbio.2022.01.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 11/28/2022]
Abstract
The mechanical properties of connective tissues are tailored to their specific function, and changes can lead to dysfunction and pathology. In most mammalian tissues the mechanical environment is governed by the micro- and nano-scale structure of collagen and its interaction with other tissue components, however these hierarchical properties remain poorly understood. In this study we use the human cornea as a model system to characterise and quantify the dominant deformation mechanisms of connective tissue in response to cyclic loads of physiological magnitude. Synchronised biomechanical testing, x-ray scattering and 3D digital image correlation revealed the presence of two dominant mechanisms: collagen fibril elongation due to a largely elastic, spring-like straightening of tropocollagen supramolecular twist, and a more viscous straightening of fibril crimp that gradually increased over successive loading cycles. The distinct mechanical properties of the two mechanisms suggest they have separate roles in vivo. The elastic, spring-like mechanism is fast-acting and likely responds to stresses associated with the cardiac cycle, while the more viscous crimp mechanism will respond to slower processes, such as postural stresses. It is anticipated that these findings will have broad applicability to understanding the normal and pathological functioning of other connective tissues such as skin and blood vessels that exhibit both helical structures and crimp. Statement of significance The tropocollagen spring mechanism allows collagen fibrils from some tissues to elongate significantly under small loads, and its recent discovery has the potential to change our fundamental understanding of how tissue deforms. This time-resolved study quantifies the contribution of the spring mechanism to the local strain in stretched tissue and compares it to the contribution associated with the straightening of fibril waviness, the widely accepted primary low-load strain mechanism. The spring mechanism contributed more to the local tissue strain than fibril straightening, and was found to be elastic while fibril straightening was more viscous. The results suggest that the viscoelastic behaviour of a biomaterial is controlled, at least in part, by the relative amount of fibril-scale crimp and tropocollagen supramolecular twist.
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23
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Zhang W, Schönberg A, Hamdorf M, Georgiev T, Cursiefen C, Bock F. Preincubation of donor tissue with a VEGF cytokine trap promotes subsequent high-risk corneal transplant survival. Br J Ophthalmol 2021; 106:1617-1626. [PMID: 34810177 DOI: 10.1136/bjophthalmol-2021-319745] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 09/07/2021] [Indexed: 11/03/2022]
Abstract
AIMS Pathological neovascularisation of the host bed and the transplant itself is the main risk factor for graft rejection after corneal transplantation. This study aims to prevent this process by preincubation of the corneal donor tissue ex vivo with an antivascular endothelial growth factor (VEGF) cytokine trap blocking additional postsurgical hemangiogenesis and lymphangiogenesis to promote high-risk graft survival. METHODS The donor tissue was preincubated with a VEGFR1R2 cytokine trap for 24 hours prior to murine high-risk corneal transplantation (human IgG Fc was used as the control). The distribution of VEGFR1R2 Trap in the cornea was investigated by immunohistochemistry. Corneas were excised to quantify the blood vessels (BVs) and lymphatic vessels (LVs) and draining lymph nodes (dLNs) were harvested to analyse the phenotype of dendritic cells (DCs) and T cells at week 1, 2 and 8 post-transplantation. Graft survival was compared between preincubation with VEGFR1R2 Trap and human IgG Fc in high-risk recipients. RESULTS VEGFR1R2 Trap was present in the graft for at least 2 weeks after surgery and additionally diffused into the corneal recipient. BVs, LVs and macrophages in the whole cornea were significantly decreased 1-week and 2-week post-transplantation (p<0.05). In dLNs the frequency of CD11c+DCs was significantly reduced, whereas CD200R+ regulatory DCs were significantly increased after keratoplasty (p<0.05). Furthermore, long-term high-risk graft survival was significantly improved (p<0.01). CONCLUSIONS Preincubation of corneal donor tissue with a VEGFR1R2 cytokine trap can significantly promote subsequent high-risk corneal transplant survival and thereby opens new treatment avenues for high-risk corneal transplantation.
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Affiliation(s)
- Wei Zhang
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Department of Ophthalmology, Hebei Eye Hospital, Xingtai, Hebei, China
| | - Alfrun Schönberg
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Matthias Hamdorf
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Tihomir Georgiev
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany
| | - Claus Cursiefen
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
| | - Felix Bock
- Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany .,Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
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Kaya SG, Inanc-Surer S, Cakan-Akdogan G, Oktay G, Utine CA, Kalyoncu S. Roles of matrix metalloproteinases in the cornea: A special focus on macular corneal dystrophy. MEDICINE IN DRUG DISCOVERY 2021. [DOI: 10.1016/j.medidd.2021.100095] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
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25
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Zhu Y, Cheung ALM. Proteoglycans and their functions in esophageal squamous cell carcinoma. World J Clin Oncol 2021; 12:507-521. [PMID: 34367925 PMCID: PMC8317653 DOI: 10.5306/wjco.v12.i7.507] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 04/13/2021] [Accepted: 06/02/2021] [Indexed: 02/06/2023] Open
Abstract
Esophageal squamous cell carcinoma (ESCC) is a highly malignant disease that has a poor prognosis. Its high lethality is mainly due to the lack of symptoms at early stages, which culminates in diagnosis at a late stage when the tumor has already metastasized. Unfortunately, the common cancer biomarkers have low sensitivity and specificity in esophageal cancer. Therefore, a better understanding of the molecular mechanisms underlying ESCC progression is needed to identify novel diagnostic markers and therapeutic targets for intervention. The invasion of cancer cells into the surrounding tissue is a crucial step for metastasis. During metastasis, tumor cells can interact with extracellular components and secrete proteolytic enzymes to remodel the surrounding tumor microenvironment. Proteoglycans are one of the major components of extracellular matrix. They are involved in multiple processes of cancer cell invasion and metastasis by interacting with soluble bioactive molecules, surrounding matrix, cell surface receptors, and enzymes. Apart from having diverse functions in tumor cells and their surrounding microenvironment, proteoglycans also have diagnostic and prognostic significance in cancer patients. However, the functional significance and underlying mechanisms of proteoglycans in ESCC are not well understood. This review summarizes the proteoglycans that have been studied in ESCC in order to provide a comprehensive view of the role of proteoglycans in the progression of this cancer type. A long term goal would be to exploit these molecules to provide new strategies for therapeutic intervention.
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Affiliation(s)
- Yun Zhu
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong, China
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26
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Tiwari N, Wi S, Mentink-Vigier F, Sinha N. Mechanistic Insights into the Structural Stability of Collagen-Containing Biomaterials Such as Bones and Cartilage. J Phys Chem B 2021; 125:4757-4766. [PMID: 33929847 PMCID: PMC8151626 DOI: 10.1021/acs.jpcb.1c01431] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Structural stability of various collagen-containing biomaterials such as bones and cartilage is still a mystery. Despite the spectroscopic development of several decades, the detailed mechanism of collagen interaction with citrate in bones and glycosaminoglycans (GAGs) in the cartilage extracellular matrix (ECM) in its native state is unobservable. We present a significant advancement to probe the collagen interactions with citrate and GAGs in the ECM of native bones and cartilage along with specific/non-specific interactions inside the collagen assembly at the nanoscopic level through natural-abundance dynamic nuclear polarization-based solid-state nuclear magnetic resonance spectroscopy. The detected molecular-level interactions between citrate-collagen and GAG-collagen inside the native bone and cartilage matrices and other backbone and side-chain interactions in the collagen assembly are responsible for the structural stability and other biomechanical properties of these important classes of biomaterials.
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Affiliation(s)
- Nidhi Tiwari
- Centre of Biomedical Research, SGPGIMS Campus, Raebarelly Road, Lucknow – 226014, INDIA
- Department of Chemistry, Institute of Sciences, Banaras Hindu University, Varanasi – 221005, INDIA
| | - Sungsool Wi
- National High Magnetic Field Laboratory, Tallahassee, Florida 32304, USA
| | | | - Neeraj Sinha
- Centre of Biomedical Research, SGPGIMS Campus, Raebarelly Road, Lucknow – 226014, INDIA
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27
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Chauhan BK, Medsinge A, Scanga HL, Chu CT, Nischal KK. Transcriptome from opaque cornea of Fanconi anemia patient uncovers fibrosis and two connected players. Mol Genet Metab Rep 2021; 26:100712. [PMID: 33552906 PMCID: PMC7846932 DOI: 10.1016/j.ymgmr.2021.100712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2020] [Revised: 01/15/2021] [Accepted: 01/16/2021] [Indexed: 11/28/2022] Open
Abstract
Congenital corneal opacities (CCO) are a group of blinding corneal disorders, where the underlying molecular mechanisms are poorly understood. Phenotyping through specialized imaging and histopathology analysis, together with assessment of key transcriptomic changes (including glycosaminoglycan metabolic enzymes) in cornea(s) with CCO from a case of Fanconi anemia is the approach taken in this study to identify causal mechanisms. Based on our findings, we propose a novel mechanism and two key players contributing to CCO.
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Affiliation(s)
- Bharesh K Chauhan
- UPMC Eye Center, Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA.,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Anagha Medsinge
- UPMC Eye Center, Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Hannah L Scanga
- UPMC Eye Center, Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA
| | - Charleen T Chu
- Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
| | - Ken K Nischal
- UPMC Eye Center, Children's Hospital of Pittsburgh, Pittsburgh, PA 15224, USA.,Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
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28
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López-Cano JJ, González-Cela-Casamayor MA, Andrés-Guerrero V, Herrero-Vanrell R, Molina-Martínez IT. Liposomes as vehicles for topical ophthalmic drug delivery and ocular surface protection. Expert Opin Drug Deliv 2021; 18:819-847. [PMID: 33412914 DOI: 10.1080/17425247.2021.1872542] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Introduction: The development of ophthalmic formulations able to deliver hydrophilic and hydrophobic drugs to the inner structures of the eye and restore the preocular tear film has been a leading topic of discussion over the last few years. In this sense, liposomes represent a suitable strategy to achieve these objectives in ocular drug delivery.Areas covered: Knowledge of the different physiological and anatomical eye structures, and specially the ocular surface are critical to better understanding and comprehending the characteristics required for the development of topical ophthalmic liposomal formulations. In this review, several features of liposomes are discussed such as the main materials used for their fabrication, basic structure and preparation methods, from already established to novel techniques, allowing the control and design of special characteristics. Besides, physicochemical properties, purification processes and strategies to overcome delivery or encapsulation challenges are also presented. Expert opinion: Regarding ocular drug delivery of liposomes, there are some features that can be redesigned. Specific biocompatible and biodegradable materials presenting therapeutic properties, such as lipidic compounds or polymers significantly change the way of tackling ophthalmic diseases. Besides, liposomes entail an effective, safe and versatile strategy for the treatment of diseases in the clinical practice.
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Affiliation(s)
- José Javier López-Cano
- Department of Pharmaceutics and Food Technology, Complutense University, Madrid, Spain.,Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (Idissc), Madrid Spain
| | - Miriam Ana González-Cela-Casamayor
- Department of Pharmaceutics and Food Technology, Complutense University, Madrid, Spain.,Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (Idissc), Madrid Spain
| | - Vanessa Andrés-Guerrero
- Department of Pharmaceutics and Food Technology, Complutense University, Madrid, Spain.,Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (Idissc), Madrid Spain
| | - Rocío Herrero-Vanrell
- Department of Pharmaceutics and Food Technology, Complutense University, Madrid, Spain.,Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (Idissc), Madrid Spain
| | - Irene Teresa Molina-Martínez
- Department of Pharmaceutics and Food Technology, Complutense University, Madrid, Spain.,Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (Idissc), Madrid Spain
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29
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Ashworth S, Harrington J, Hammond GM, Bains KK, Koudouna E, Hayes AJ, Ralphs JR, Regini JW, Young RD, Hayashi R, Nishida K, Hughes CE, Quantock AJ. Chondroitin Sulfate as a Potential Modulator of the Stem Cell Niche in Cornea. Front Cell Dev Biol 2021; 8:567358. [PMID: 33511110 PMCID: PMC7835413 DOI: 10.3389/fcell.2020.567358] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 12/07/2020] [Indexed: 12/13/2022] Open
Abstract
Chondroitin sulfate (CS) is an important component of the extracellular matrix in multiple biological tissues. In cornea, the CS glycosaminoglycan (GAG) exists in hybrid form, whereby some of the repeating disaccharides are dermatan sulfate (DS). These CS/DS GAGs in cornea, through their presence on the proteoglycans, decorin and biglycan, help control collagen fibrillogenesis and organization. CS also acts as a regulatory ligand for a spectrum of signaling molecules, including morphogens, cytokines, chemokines, and enzymes during corneal growth and development. There is a growing body of evidence that precise expression of CS or CS/DS with specific sulfation motifs helps define the local extracellular compartment that contributes to maintenance of the stem cell phenotype. Indeed, recent evidence shows that CS sulfation motifs recognized by antibodies 4C3, 7D4, and 3B3 identify stem cell populations and their niches, along with activated progenitor cells and transitional areas of tissue development in the fetal human elbow. Various sulfation motifs identified by some CS antibodies are also specifically located in the limbal region at the edge of the mature cornea, which is widely accepted to represent the corneal epithelial stem cell niche. Emerging data also implicate developmental changes in the distribution of CS during corneal morphogenesis. This article will reflect upon the potential roles of CS and CS/DS in maintenance of the stem cell niche in cornea, and will contemplate the possible involvement of CS in the generation of eye-like tissues from human iPS (induced pluripotent stem) cells.
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Affiliation(s)
- Sean Ashworth
- Structural Biophysics Group, School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom.,School of Biosciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
| | - Jodie Harrington
- Structural Biophysics Group, School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom.,Department of Stem Cells and Applied Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Greg M Hammond
- Structural Biophysics Group, School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
| | - Kiranjit K Bains
- Structural Biophysics Group, School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
| | - Elena Koudouna
- Structural Biophysics Group, School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
| | - Anthony J Hayes
- School of Biosciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
| | - James R Ralphs
- School of Biosciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
| | - Justyn W Regini
- Structural Biophysics Group, School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
| | - Robert D Young
- Structural Biophysics Group, School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
| | - Ryuhei Hayashi
- Department of Stem Cells and Applied Medicine, Osaka University Graduate School of Medicine, Osaka, Japan.,Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Kohji Nishida
- Department of Ophthalmology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Clare E Hughes
- School of Biosciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
| | - Andrew J Quantock
- Structural Biophysics Group, School of Optometry and Vision Sciences, College of Biomedical and Life Sciences, Cardiff University, Cardiff, United Kingdom
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30
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Latorre ME, Velazquez DE. Effects of thermal treatment on collagen present in bovine M. Semitendinosus intramuscular connective tissue. Analysis of the chemical, thermal and mechanical properties. FOOD STRUCTURE 2021. [DOI: 10.1016/j.foostr.2020.100165] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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31
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Borrelli C, Buckley CT. Injectable Disc-Derived ECM Hydrogel Functionalised with Chondroitin Sulfate for Intervertebral Disc Regeneration. Acta Biomater 2020; 117:142-155. [PMID: 33035694 DOI: 10.1016/j.actbio.2020.10.002] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 09/30/2020] [Accepted: 10/01/2020] [Indexed: 12/13/2022]
Abstract
Low back pain resulting from intervertebral disc (IVD) degeneration is a significant socioeconomic burden. The main effect of the degeneration process involves the alteration of the nucleus pulposus (NP) via cell-mediated enzymatic breakdown of key extracellular matrix (ECM) components. Thus, the development of injectable and biomimetic biomaterials that can instruct the regenerative cell component to produce tissue-specific ECM is pivotal for IVD repair. Chondroitin sulfate (CS) and type II collagen are the primary components of NP tissue and together create the ideal environment for cells to deposit de-novo matrix. Given their high matrix synthesis capacity potential post-expansion, nasal chondrocytes (NC) have been proposed as a potential cell source to promote NP repair. The overall goal of this study was to assess the effects of CS incorporation into disc derived self-assembled ECM hydrogels on the matrix deposition of NCs. Results showed an increased sGAG production with higher amounts of CS in the gel composition and that its presence was found to be critical for the synthesis of collagen type II. Taken together, our results demonstrate how the inclusion of CS into the composition of the material aids the preservation of a rounded cell morphology for NCs in 3D culture and enhances their ability to synthesise NP-like matrix.
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32
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On influence of sulfated glycosaminoglycans on tensile properties of posterior sclera. ACTA ACUST UNITED AC 2020. [DOI: 10.1007/s42558-020-00025-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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33
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Corneal Stem Cells as a Source of Regenerative Cell-Based Therapy. Stem Cells Int 2020; 2020:8813447. [PMID: 32765614 PMCID: PMC7388005 DOI: 10.1155/2020/8813447] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 07/03/2020] [Accepted: 07/10/2020] [Indexed: 12/15/2022] Open
Abstract
In the past few years, intensive research has focused on corneal stem cells as an unlimited source for cell-based therapy in regenerative ophthalmology. Today, it is known that the cornea has at least two types of stem cells: limbal epithelial stem cells (LESCs) and corneal stromal stem cells (CSSCs). LESCs are used for regeneration of corneal surface, while CSSCs are used for regeneration of corneal stroma. Until now, various approaches and methods for isolation of LESCs and CSSCs and their successful transplantation have been described and tested in several preclinical studies and clinical trials. This review describes in detail phenotypic characteristics of LESCs and CSSCs and discusses their therapeutic potential in corneal regeneration. Since efficient and safe corneal stem cell-based therapy is still a challenging issue that requires continuous cooperation between researchers, clinicians, and patients, this review addresses the important limitations and suggests possible strategies for improvement of corneal stem cell-based therapy.
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34
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Liu ZQ, Zhou DY, Liu YX, Yu MM, Liu B, Song L, Dong XP, Qi H, Shahidi F. Inhibitory effect of natural metal ion chelators on the autolysis of sea cucumber (Stichopus japonicus) and its mechanism. Food Res Int 2020; 133:109205. [PMID: 32466945 DOI: 10.1016/j.foodres.2020.109205] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 03/05/2020] [Accepted: 03/27/2020] [Indexed: 11/26/2022]
Abstract
Live sea cucumbers (Stichopus japonicus) were stored in a solution containing oxalic acid and tea polyphenols as natural metal ion chelators. The inhibitory effects of these chelators on the autolysis phenomenon and the underlying mechanism of action were investigated for the first time by using scanning electron microscopy, differential scanning calorimetry, low-field nuclear magnetic resonance and confocal laser scanning microscopy. External stimuli cause autolysis through the release of calcium ions (Ca2+) from cells into the extracellular connective tissue, initiating activity of the matrix metalloprotease (MMP) in the sea cucumber body wall (SCBW). MMP subsequently degrades the microfibrillar networks, that support the interconnecting collagen fibres and the interfibrillar proteoglycan bridges linking the collagen fibrils, to release the water restricted within the interspaces between collagen fibres and collagen fibrils, ultimately causing mucoid degeneration of SCBW. The natural metal ion chelators significantly inhibited the activation of MMP by chelating Ca2+, consequently effectively preventing the autolysis of SCBW.
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Affiliation(s)
- Zi-Qiang Liu
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China.
| | - Da-Yong Zhou
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China; National Engineering Research Center of Seafood, Dalian 116034, PR China.
| | - Yu-Xin Liu
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China; National Engineering Research Center of Seafood, Dalian 116034, PR China.
| | - Man-Man Yu
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China.
| | - Bing Liu
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China; National Engineering Research Center of Seafood, Dalian 116034, PR China.
| | - Liang Song
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China; National Engineering Research Center of Seafood, Dalian 116034, PR China.
| | - Xiu-Ping Dong
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China; National Engineering Research Center of Seafood, Dalian 116034, PR China.
| | - Hang Qi
- School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China; National Engineering Research Center of Seafood, Dalian 116034, PR China.
| | - Fereidoon Shahidi
- Department of Biochemistry, Memorial University of Newfoundland, St. John's, NL A1B3X9, Canada.
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35
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Zappia J, Joiret M, Sanchez C, Lambert C, Geris L, Muller M, Henrotin Y. From Translation to Protein Degradation as Mechanisms for Regulating Biological Functions: A Review on the SLRP Family in Skeletal Tissues. Biomolecules 2020; 10:E80. [PMID: 31947880 PMCID: PMC7023458 DOI: 10.3390/biom10010080] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 12/19/2019] [Accepted: 12/26/2019] [Indexed: 12/27/2022] Open
Abstract
The extracellular matrix can trigger cellular responses through its composition and structure. Major extracellular matrix components are the proteoglycans, which are composed of a core protein associated with glycosaminoglycans, among which the small leucine-rich proteoglycans (SLRPs) are the largest family. This review highlights how the codon usage pattern can be used to modulate cellular response and discusses the biological impact of post-translational events on SLRPs, including the substitution of glycosaminoglycan moieties, glycosylation, and degradation. These modifications are listed, and their impacts on the biological activities and structural properties of SLRPs are described. We narrowed the topic to skeletal tissues undergoing dynamic remodeling.
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Affiliation(s)
- Jérémie Zappia
- Bone and Cartilage Research Unit, Arthropôle Liège, Center for Interdisciplinary research on Medicines (CIRM) Liège, Liège University, Institute of Pathology, CHU Sart-Tilman, 4000 Liège, Belgium; (J.Z.); (C.S.); (C.L.)
| | - Marc Joiret
- Biomechanics Research Unit, B34 GIGA-R, In Silico Medicine, Liège University, CHU Sart-Tilman, 4000 Liège, Belgium; (M.J.); (L.G.)
| | - Christelle Sanchez
- Bone and Cartilage Research Unit, Arthropôle Liège, Center for Interdisciplinary research on Medicines (CIRM) Liège, Liège University, Institute of Pathology, CHU Sart-Tilman, 4000 Liège, Belgium; (J.Z.); (C.S.); (C.L.)
| | - Cécile Lambert
- Bone and Cartilage Research Unit, Arthropôle Liège, Center for Interdisciplinary research on Medicines (CIRM) Liège, Liège University, Institute of Pathology, CHU Sart-Tilman, 4000 Liège, Belgium; (J.Z.); (C.S.); (C.L.)
| | - Liesbet Geris
- Biomechanics Research Unit, B34 GIGA-R, In Silico Medicine, Liège University, CHU Sart-Tilman, 4000 Liège, Belgium; (M.J.); (L.G.)
| | - Marc Muller
- Laboratory for Organogenesis and Regeneration (LOR), GIGA-Research, Liège University, Avenue de l’Hôpital, B-4000 Liège, Belgium;
| | - Yves Henrotin
- Bone and Cartilage Research Unit, Arthropôle Liège, Center for Interdisciplinary research on Medicines (CIRM) Liège, Liège University, Institute of Pathology, CHU Sart-Tilman, 4000 Liège, Belgium; (J.Z.); (C.S.); (C.L.)
- Physical therapy and Rehabilitation department, Princess Paola Hospital, Vivalia, B-6900 Marche-en-Famenne, Belgium
- Artialis SA, GIGA Tower, Level 3, CHU Sart-Tilman, 4000 Liège, Belgium
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Cell-independent matrix configuration in early corneal development. Exp Eye Res 2019; 187:107772. [PMID: 31445001 PMCID: PMC6892249 DOI: 10.1016/j.exer.2019.107772] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/01/2019] [Accepted: 08/20/2019] [Indexed: 01/01/2023]
Abstract
Mechanisms controlling the spatial configuration of the remarkably ordered collagen-rich extracellular matrix of the transparent cornea remain incompletely understood. We previously described the assembly of the emerging corneal matrix in the mid and late stages of embryogenesis and concluded that collagen fibril organisation was driven by cell-directed mechanisms. Here, the early stages of corneal morphogenesis were examined by serial block face scanning electron microscopy of embryonic chick corneas starting at embryonic day three (E3), followed by a Fourier transform analysis of three-dimensional datasets and theoretical considerations of factors that influence matrix formation. Eyes developing normally and eyes that had the lens surgically removed at E3 were studied. Uniformly thin collagen fibrils are deposited by surface ectoderm-derived corneal epithelium in the primary stroma of the developing chick cornea and form an acellular matrix with a striking micro-lamellar orthogonal arrangement. Fourier transform analysis supported this observation and indicated that adjacent micro-lamellae display a clockwise rotation of fibril orientation, depth-wise below the epithelium. We present a model which attempts to explain how, in the absence of cells in the primary stroma, collagen organisation might be influenced by cell-independent, intrinsic mechanisms, such as fibril axial charge derived from associated proteoglycans. On a supra-lamellar scale, fine cords of non-collagenous filamentous matrix were detected over large tissue volumes. These extend into the developing cornea from the epithelial basal lamina and appear to associate with the neural crest cells that migrate inwardly to form, first the corneal endothelium and then keratocytes which synthesise the mature, secondary corneal stroma. In a small number of experimental specimens, matrix cords were present even when periocular neural crest cell migration and corneal morphogenesis had been perturbed following removal of the lens at E3.
Highly-ordered connective tissue appears early in development of the avian cornea. Cell-independent mechanisms may contribute to the organisation of collagen fibrils into an orthogonal array. Matrix cords from epithelium into stroma contact invading neural crest cells.
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37
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He F, Liu J, Ye P, Wu J, Liang G, Xu W. Biophysical and microstructural changes of swelling cornea caused by endothelial cells damage. Physiol Res 2019; 68:827-833. [PMID: 31424248 DOI: 10.33549/physiolres.934011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Biophysical properties and microstructural changes of swelling cornea which caused by endothelial cells damage will be evaluated. Swelling cornea models were established by endothelial cells damage in 114 Sprague Dawley rats. Relative gray value, swelling rate and light transmittance were measured to evaluated the biophysical properties and microstructure changes were observed by transmission electron microscopy. Relative gray value decreased while swelling rate rose along with time and both of them reached relative stability after 7 days. Light transmittance showed a decline trend with time even after corneal thickness had reached stable stage. Observed by transmission electron microscopy, interfibrillar distance increased, fewer proteoglycans coating appeared and remnants proteoglycan branches became thinner and longer in 7 days. Diameter of fibrils didn't change obviously with time. In cornea edema models caused by endothelial cells damage, the changes of biophysical property and microstructure can help us evaluate corneal edema accurately and objectively.
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Affiliation(s)
- F He
- Eye Center, Second Affiliated Hospital of Zhejiang University, College of Medicine, Hangzhou, China.
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38
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Moorehead C, Prudnikova K, Marcolongo M. The regulatory effects of proteoglycans on collagen fibrillogenesis and morphology investigated using biomimetic proteoglycans. J Struct Biol 2019; 206:204-215. [DOI: 10.1016/j.jsb.2019.03.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/11/2019] [Accepted: 03/13/2019] [Indexed: 01/26/2023]
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39
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Kriete AS, Ginzburg N, Shah N, Huneke RB, Reimold E, Prudnikova K, Montgomery O, Hou JS, Phillips ER, Marcolongo MS. In vivo
molecular engineering of the urethra for treatment of stress incontinence using novel biomimetic proteoglycans. J Biomed Mater Res B Appl Biomater 2019; 107:2409-2418. [DOI: 10.1002/jbm.b.34334] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 12/26/2018] [Accepted: 01/13/2019] [Indexed: 01/17/2023]
Affiliation(s)
- Alicia S. Kriete
- Materials Science and EngineeringDrexel University Philadelphia Pennsylvania 19104
| | - Natasha Ginzburg
- College of MedicineDrexel University Philadelphia Pennsylvania 19129
| | - Nima Shah
- College of MedicineDrexel University Philadelphia Pennsylvania 19129
| | - Richard B. Huneke
- College of MedicineDrexel University Philadelphia Pennsylvania 19129
| | - Emily Reimold
- College of MedicineDrexel University Philadelphia Pennsylvania 19129
| | | | - Owen Montgomery
- College of MedicineDrexel University Philadelphia Pennsylvania 19129
| | - J. Steve Hou
- College of MedicineDrexel University Philadelphia Pennsylvania 19129
| | - Evan R. Phillips
- Materials Science and EngineeringDrexel University Philadelphia Pennsylvania 19104
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Craniofacial abnormality with skeletal dysplasia in mice lacking chondroitin sulfate N-acetylgalactosaminyltransferase-1. Sci Rep 2018; 8:17134. [PMID: 30459452 PMCID: PMC6244165 DOI: 10.1038/s41598-018-35412-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 11/02/2018] [Indexed: 02/03/2023] Open
Abstract
Chondroitin sulfate (CS) proteoglycan is a major component of the extracellular matrix and plays an important part in organogenesis. To elucidate the roles of CS for craniofacial development, we analyzed the craniofacial morphology in CS N-acetylgalactosaminyltransferase-1 (T1) gene knockout (KO) mice. T1KO mice showed the impaired intramembranous ossification in the skull, and the final skull shape of adult mice included a shorter face, higher and broader calvaria. Some of T1KO mice exhibited severe facial developmental defect, such as eye defects and cleft lip and palate, causing embryonic lethality. At the postnatal stages, T1KO mice with severely reduced CS amounts showed malocclusion, general skeletal dysplasia and skin hyperextension, closely resembling Ehlers-Danlos syndrome-like connective tissue disorders. The production of collagen type 1 was significantly downregulated in T1KO mice, and the deposition of CS-binding molecules, Wnt3a, was decreased with CS in extracellular matrices. The collagen fibers were irregular and aggregated, and connective tissues were dysorganized in the skin and calvaria of T1KO mice. These results suggest that CS regulates the shape of the craniofacial skeleton by modulating connective tissue organization and that the remarkable reduction of CS induces hypoplasia of intramembranous ossification and cartilage anomaly, resulting in skeletal dysplasia.
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Contributions of Glycosaminoglycans to Collagen Fiber Recruitment in Constitutive Modeling of Arterial Mechanics. J Biomech 2018; 82:211-219. [PMID: 30415914 DOI: 10.1016/j.jbiomech.2018.10.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2018] [Revised: 10/20/2018] [Accepted: 10/23/2018] [Indexed: 01/08/2023]
Abstract
The contribution of glycosaminoglycans (GAGs) to the biological and mechanical functions of biological tissue has emerged as an important area of research. GAGs provide structural basis for the organization and assembly of extracellular matrix (ECM). The mechanics of tissue with low GAG content can be indirectly affected by the interaction of GAGs with collagen fibers, which have long been known to be one of the primary contributors to soft tissue mechanics. Our earlier study showed that enzymatic GAG depletion results in straighter collagen fibers that are recruited at lower levels of stretch, and a corresponding shift in earlier arterial stiffening (Mattson et al., 2016). In this study, the effect of GAGs on collagen fiber recruitment was studied through a structure-based constitutive model. The model incorporates structural information, such as fiber orientation distribution, content, and recruitment of medial elastin, medial collagen, and adventitial collagen fibers. The model was first used to study planar biaxial tensile stress-stretch behavior of porcine descending thoracic aorta. Changes in elastin and collagen fiber orientation distribution, and collagen fiber recruitment were then incorporated into the model in order to predict the stress-stretch behavior of GAG depleted tissue. Our study shows that incorporating early collagen fiber recruitment into the model predicts the stress-stretch response of GAG depleted tissue reasonably well (rms = 0.141); considering further changes of fiber orientation distribution does not improve the predicting capability (rms = 0.149). Our study suggests an important role of GAGs in arterial mechanics that should be considered in developing constitutive models.
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Nugroho RWN, Harjumäki R, Zhang X, Lou YR, Yliperttula M, Valle-Delgado JJ, Österberg M. Quantifying the interactions between biomimetic biomaterials - collagen I, collagen IV, laminin 521 and cellulose nanofibrils - by colloidal probe microscopy. Colloids Surf B Biointerfaces 2018; 173:571-580. [PMID: 30347384 DOI: 10.1016/j.colsurfb.2018.09.073] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 09/12/2018] [Accepted: 09/28/2018] [Indexed: 12/16/2022]
Abstract
Biomaterials of different nature have been and are widely studied for various biomedical applications. In many cases, biomaterial assemblies are designed to mimic biological systems. Although biomaterials have been thoroughly characterized in many aspects, not much quantitative information on the molecular level interactions between different biomaterials is available. That information is very important, on the one hand, to understand the properties of biological systems and, on the other hand, to develop new composite biomaterials for special applications. This work presents a systematic, quantitative analysis of self- and cross-interactions between films of collagen I (Col I), collagen IV (Col IV), laminin (LN-521), and cellulose nanofibrils (CNF), that is, biomaterials of different nature and structure that either exist in biological systems (e.g., extracellular matrices) or have shown potential for 3D cell culture and tissue engineering. Direct surface forces and adhesion between biomaterials-coated spherical microparticles and flat substrates were measured in phosphate-buffered saline using an atomic force microscope and the colloidal probe technique. Different methods (Langmuir-Schaefer deposition, spin-coating, or adsorption) were applied to completely coat the flat substrates and the spherical microparticles with homogeneous biomaterial films. The adhesion between biomaterials films increased with the time that the films were kept in contact. The strongest adhesion was observed between Col IV films, and between Col IV and LN-521 films after 30 s contact time. In contrast, low adhesion was measured between CNF films, as well as between CNF and LN-521 films. Nevertheless, a good adhesion between CNF and collagen films (especially Col I) was observed. These results increase our understanding of the structure of biological systems and can support the design of new matrices or scaffolds where different biomaterials are combined for diverse biological or medical applications.
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Affiliation(s)
- Robertus Wahyu N Nugroho
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Riina Harjumäki
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland; Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland
| | - Xue Zhang
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland
| | - Yan-Ru Lou
- Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland
| | - Marjo Yliperttula
- Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, FI-00014 Helsinki, Finland; Department of Pharmaceutical and Pharmacological Sciences, University of Padova, I-35131 Padova, Italy
| | - Juan José Valle-Delgado
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland.
| | - Monika Österberg
- Department of Bioproducts and Biosystems, School of Chemical Engineering, Aalto University, FI-00076 Aalto, Finland.
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Microwave treatment of the cornea leads to localised disruption of the extracellular matrix. Sci Rep 2018; 8:13742. [PMID: 30213993 PMCID: PMC6137159 DOI: 10.1038/s41598-018-32110-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 08/31/2018] [Indexed: 11/11/2022] Open
Abstract
Microwave keratoplasty is a thermo-refractive surgical procedure that can correct myopia (short-sightedness) and pathologic corneal steepening by using microwave energy to cause localised shrinkage around an annulus of the cornea leading to its flattening and vision correction. The effects on the corneal extracellular matrix, however, have not yet been evaluated, thus the current study to assess post-procedure ultrastructural changes in an in-vivo rabbit model. To achieve this a series of small-angle x-ray scattering (SAXS) experiments were carried out across whole transects of treated and untreated rabbit corneas at 0.25 mm intervals, which indicated no significant change in collagen intra-fibrillar parameters (i.e. collagen fibril diameter or axial D-period), whereas inter-fibrillar measures (i.e. fibril spacing and the degree of spatial order) were markedly altered in microwave-treated regions of the cornea. These structural matrix alterations in microwave-treated corneas have predicted implications for corneal biomechanical strength and tissue transparency, and, we contend, potentially render microwave-treated corneas resistant to surgical stabilization using corneal cross-linking procedures currently employed to combat refractive error caused by corneal steepening.
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Zappone B, Patil NJ, Lombardo M, Lombardo G. Transient viscous response of the human cornea probed with the Surface Force Apparatus. PLoS One 2018; 13:e0197779. [PMID: 29799859 PMCID: PMC5969749 DOI: 10.1371/journal.pone.0197779] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 05/08/2018] [Indexed: 01/07/2023] Open
Abstract
Knowledge of the biomechanical properties of the human cornea is crucial for understanding the development of corneal diseases and impact of surgical treatments (e.g., corneal laser surgery, corneal cross-linking). Using a Surface Force Apparatus we investigated the transient viscous response of the anterior cornea from donor human eyes compressed between macroscopic crossed cylinders. Corneal biomechanics was analyzed using linear viscoelastic theory and interpreted in the framework of a biphasic model of soft hydrated porous tissues, including a significant contribution from the pressurization and viscous flow of fluid within the corneal tissue. Time-resolved measurements of tissue deformation and careful determination of the relaxation time provided an elastic modulus in the range between 0.17 and 1.43 MPa, and fluid permeability of the order of 10−13 m4/(N∙s). The permeability decreased as the deformation was increased above a strain level of about 10%, indicating that the interstitial space between fibrils of the corneal stromal matrix was reduced under the effect of strong compression. This effect may play a major role in determining the observed rate-dependent non-linear stress-strain response of the anterior cornea, which underlies the shape and optical properties of the tissue.
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Affiliation(s)
- Bruno Zappone
- Consiglio Nazionale delle Ricerche, Istituto di Nanotecnologia (CNR-Nanotec), Rende (CS), Italy
- * E-mail: (BZ); (GL)
| | | | | | - Giuseppe Lombardo
- Consiglio Nazionale delle Ricerche, Istituto per i Processi Chimico-Fisici (CNR-IPCF), Messina, Italy
- * E-mail: (BZ); (GL)
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Hatami-Marbini H, Jayaram SM. UVA/riboflavin collagen crosslinking stiffening effects on anterior and posterior corneal flaps. Exp Eye Res 2018; 176:53-58. [PMID: 29777678 DOI: 10.1016/j.exer.2018.05.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/04/2018] [Accepted: 05/15/2018] [Indexed: 10/16/2022]
Abstract
The UVA/riboflavin collagen crosslinking (CXL) is one of the treatment procedure for stopping the progression of keratoconus. The inclusion criterion for this procedure is a minimum corneal thickness of 400 μm, which is not often met in patients with advanced keratoconus. Preoperatively swelling thin corneas was shown to stabilize the keratectasia without any postoperative endothelial damage. Recently, we have shown that swelling porcine corneas prior to the CXL treatment had no significant effect on the resulting improvement in their tensile properties. In the present study, we extended this previous study and characterized the stiffening effects of CXL on anterior and posterior flaps as a function of their hydration. A DSAEK system was used to excise 10 mm corneal flaps from 80 porcine corneas. Individual flaps were crosslinked at different initial hydration levels by using riboflavin solutions composed of different dextran concentrations; the thickness was taken as a measure of flap hydration. A DMA machine was used to measure the tensile properties either immediately after the CXL treatment or after the thickness (hydration) of the crosslinked samples was brought down to a specific value. The average thickness of anterior groups was 670 μm, 540 μm, and 410 μm, and the average thickness of posterior groups was 845 μm, 650 μm, and 440 μm. It was found that although CXL significantly increased the tensile properties of all anterior groups, it had an insignificant effect on the stiffness of posterior flaps. Furthermore, except for the posterior flaps in 845 μm and 650 μm thickness groups, decreasing the hydration significantly increased the tensile modulus (p < 0.05). Finally, the anterior flaps that were crosslinked at higher hydration, i.e. swollen before CXL, showed significantly less amount of stiffening in comparison with those crosslinked at lower hydration when the tensile property measurement was done at similar hydration (p < 0.05).
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Affiliation(s)
- Hamed Hatami-Marbini
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA.
| | - Sandeep M Jayaram
- Computational Biomechanics Research Laboratory, Mechanical and Industrial Engineering Department, University of Illinois at Chicago, Chicago, IL, USA
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Hayes S, White T, Boote C, Kamma-Lorger CS, Bell J, Sorenson T, Terrill N, Shebanova O, Meek KM. The structural response of the cornea to changes in stromal hydration. J R Soc Interface 2018; 14:rsif.2017.0062. [PMID: 28592658 PMCID: PMC5493790 DOI: 10.1098/rsif.2017.0062] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Accepted: 05/12/2017] [Indexed: 11/12/2022] Open
Abstract
The primary aim of this study was to quantify the relationship between corneal structure and hydration in humans and pigs. X-ray scattering data were collected from human and porcine corneas equilibrated with polyethylene glycol (PEG) to varying levels of hydration, to obtain measurements of collagen fibril diameter, interfibrillar spacing (IFS) and intermolecular spacing. Both species showed a strong positive linear correlation between hydration and IFS2 and a nonlinear, bi-phasic relationship between hydration and fibril diameter, whereby fibril diameter increased up to approximately physiological hydration, H = 3.0, with little change thereafter. Above H = 3.0, porcine corneas exhibited a larger fibril diameter than human corneas (p < 0.001). Intermolecular spacing also varied with hydration in a bi-phasic manner but reached a maximum value at a lower hydration (H = 1.5) than fibril diameter. Human corneas displayed a higher intermolecular spacing than porcine corneas at all hydrations (p < 0.0001). Human and porcine corneas required a similar PEG concentration to reach physiological hydration, suggesting that the total fixed charge that gives rise to the swelling pressure is the same. The difference in their structural responses to hydration can be explained by variations in molecular cross-linking and intra/interfibrillar water partitioning.
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Affiliation(s)
- Sally Hayes
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Tomas White
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Craig Boote
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Christina S Kamma-Lorger
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK.,ALBA Synchrotron Light Source, Cerdanyola del Vallès, Barcelona, Spain
| | - James Bell
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | | | | | | | - Keith M Meek
- Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
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Structural and biochemical changes in dermis of sea cucumber (Stichopus japonicus) during autolysis in response to cutting the body wall. Food Chem 2018; 240:1254-1261. [DOI: 10.1016/j.foodchem.2017.08.071] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 07/19/2017] [Accepted: 08/21/2017] [Indexed: 12/11/2022]
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49
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Glycosaminoglycans from bovine eye vitreous humour and interaction with collagen type II. Glycoconj J 2018; 35:119-128. [PMID: 29305777 DOI: 10.1007/s10719-017-9808-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Revised: 11/20/2017] [Accepted: 11/24/2017] [Indexed: 10/18/2022]
Abstract
Glycosaminoglycans (GAGs) play an important role in stabilizing the gel state of eye vitreous humour. In this study, the composition of GAGs present in bovine eye vitreous was characterized through disaccharide analysis by liquid chromatography-mass spectrometry. The interaction of GAGs with collagen type II was assessed using surface plasmon resonance (SPR). The percentage of hyaluronic acid (HA), chondroitin sulfate (CS) and heparan sulfate (HS), of total GAG, were 96.2%, 3.5% and 0.3%, respectively. The disaccharide composition of CS consisted of 4S (49%), 0S (38%) 6S (12%), 2S6S (1.5%) and 2S4S (0.3%). The disaccharide composition of HS consisted of 0S (80%), NS2S (7%), NS (7%), 6S (4%), NS6S (2%), and TriS, 2S and 4S6S (each at 0.1%). The average molecular weights of CS and HS were 148 kDa and 204 kDa, respectively. SPR reveals that collagen type II binds to heparin (primarily composed of TriS) with a binding affinity (K D) of 755 nM and interacts with other GAGs, including CSB and CSE. Both bovine vitreous CS and HS interact with collagen type II, with vitreous HS showing a higher binding affinity.
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50
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Wei H, Gibbs E, Zhao P, Wang N, Cofer GP, Zhang Y, Johnson GA, Liu C. Susceptibility tensor imaging and tractography of collagen fibrils in the articular cartilage. Magn Reson Med 2017; 78:1683-1690. [PMID: 28856712 PMCID: PMC5786159 DOI: 10.1002/mrm.26882] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2017] [Revised: 07/24/2017] [Accepted: 07/30/2017] [Indexed: 12/17/2022]
Abstract
PURPOSE To investigate the B0 orientation-dependent magnetic susceptibility of collagen fibrils within the articular cartilage and to determine whether susceptibility tensor imaging (STI) can detect the 3D collagen network within cartilage. METHODS Multiecho gradient echo datasets (100-μm isotropic resolution) were acquired from fixed porcine articular cartilage specimens at 9.4 T. The susceptibility tensor was calculated using phase images acquired at 12 or 15 different orientations relative to B0 . The susceptibility anisotropy of the collagen fibril was quantified and diffusion tensor imaging (DTI) was compared against STI. 3D tractography was performed to visualize and track the collagen fibrils with DTI and STI. RESULTS STI experiments showed the distinct and significant anisotropic magnetic susceptibility of collagen fibrils within the articular cartilage. STI can be used to measure and quantify susceptibility anisotropy maps. Furthermore, STI provides orientation information of the underlying collagen network via 3D tractography. CONCLUSION The findings of this study demonstrate that STI can characterize the orientation variation of collagen fibrils where diffusion anisotropy fails. We believe that STI could serve as a sensitive and noninvasive marker to study the collagen fibrils microstructure. Magn Reson Med 78:1683-1690, 2017. © 2017 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Hongjiang Wei
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | - Eric Gibbs
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
| | - Peida Zhao
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | - Nian Wang
- Center for In Vivo Microscopy, Duke University, Durham, NC, USA
| | - Gary P. Cofer
- Center for In Vivo Microscopy, Duke University, Durham, NC, USA
| | - Yuyao Zhang
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
| | | | - Chunlei Liu
- Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, CA, USA
- Helen Wills Neuroscience Institute, University of California, Berkeley, CA, USA
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