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McKay TB, Yeung V, Hutcheon AEK, Guo X, Zieske JD, Ciolino JB. Extracellular Vesicles in the Cornea: Insights from Other Tissues. Anal Cell Pathol (Amst) 2021; 2021:9983900. [PMID: 34336556 PMCID: PMC8324376 DOI: 10.1155/2021/9983900] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 07/10/2021] [Indexed: 02/07/2023] Open
Abstract
Extracellular vesicles (EVs) are phospholipid bilayer-bound particles secreted by cells that have been found to be important in mediating cell-cell communication, signal transduction, and extracellular matrix remodeling. Their role in both physiological and pathological processes has been established in different tissues throughout the human body. The human cornea functions as a transparent and refractive barrier that protects the intraocular elements from the external environment. Injury, infection, or disease may cause the loss of corneal clarity by altering extracellular matrix organization within the stroma that may lead to detrimental effects on visual acuity. Over the years, numerous studies have identified many of the growth factors (e.g., transforming growth factor-β1, thrombospondin-1, and platelet-derived growth factor) important in corneal wound healing and scarring. However, the functional role of bound factors encapsulated in EVs in the context of corneal biology is less defined. In this review, we describe the discovery and characterization of EVs in the cornea. We focus on EV-matrix interactions, potential functions during corneal wound healing, and the bioactivity of mesenchymal stem cell-derived EVs. We also discuss the development of EVs as stable, drug-loaded therapeutics for ocular applications.
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Affiliation(s)
- Tina B. McKay
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Vincent Yeung
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Audrey E. K. Hutcheon
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Xiaoqing Guo
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - James D. Zieske
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
| | - Joseph B. Ciolino
- Department of Ophthalmology, Schepens Eye Research Institute of Mass Eye and Ear, Harvard Medical School, 20 Staniford Street, Boston, MA 02114, USA
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2
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Koudouna E, Spurlin J, Babushkina A, Quantock AJ, Jester JV, Lwigale P. Recapitulation of normal collagen architecture in embryonic wounded corneas. Sci Rep 2020; 10:13815. [PMID: 32796881 PMCID: PMC7427794 DOI: 10.1038/s41598-020-70658-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 07/31/2020] [Indexed: 02/06/2023] Open
Abstract
Wound healing is characterized by cell and extracellular matrix changes mediating cell migration, fibrosis, remodeling and regeneration. We previously demonstrated that chick fetal wound healing shows a regenerative phenotype regarding the cellular and molecular organization of the cornea. However, the chick corneal stromal structure is remarkably complex in the collagen fiber/lamellar organization, involving branching and anastomosing of collagen bundles. It is unknown whether the chick fetal wound healing is capable of recapitulating this developmentally regulated organization pattern. The purpose of this study was to examine the three-dimensional collagen architecture of wounded embryonic corneas, whilst identifying temporal and spatial changes in collagen organization during wound healing. Linear corneal wounds that traversed the epithelial layer, Bowman´s layer, and anterior stroma were generated in chick corneas on embryonic day 7. Irregular thin collagen fibers are present in the wounded cornea during the early phases of wound healing. As wound healing progresses, the collagen organization dramatically changes, acquiring an orthogonal arrangement. Fourier transform analysis affirmed this observation and revealed that adjacent collagen lamellae display an angular displacement progressing from the epithelium layer towards the endothelium. These data indicate that the collagen organization of the wounded embryonic cornea recapitulate the native macrostructure.
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Affiliation(s)
- Elena Koudouna
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA.,Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
| | - James Spurlin
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, USA
| | - Anna Babushkina
- Department of Biosciences, Rice University, Houston, TX, USA
| | - Andrew J Quantock
- Structural Biophysics Research Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, Wales, UK
| | - James V Jester
- Gavin Herbert Eye Institute, University of California Irvine, Irvine, CA, USA
| | - Peter Lwigale
- Department of Biosciences, Rice University, Houston, TX, USA.
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3
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Huynh RN, Yousof M, Ly KL, Gombedza FC, Luo X, Bandyopadhyay BC, Raub CB. Microstructural densification and alignment by aspiration-ejection influence cancer cell interactions with three-dimensional collagen networks. Biotechnol Bioeng 2020; 117:1826-1838. [PMID: 32073148 DOI: 10.1002/bit.27308] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 12/17/2019] [Accepted: 02/16/2020] [Indexed: 01/18/2023]
Abstract
Extracellular matrix microstructure and mechanics are crucial to breast cancer progression and invasion into surrounding tissues. The peritumor collagen network is often dense and aligned, features which in vitro models lack. Aspiration of collagen hydrogels led to densification and alignment of microstructure surrounding embedded cancer cells. Two metastasis-derived breast cancer cell lines, MDA-MB-231 and MCF-7, were cultured in initially 4 mg/ml collagen gels for 3 days after aspiration, as well as in unaspirated control hydrogels. Videomicroscopy during aspiration, and at 0, 1, and 3 days after aspiration, epifluorescence microscopy of phalloidin-stained F-actin cytoskeleton, histological sections, and soluble metabolic byproducts from constructs were collected to characterize effects on the embedded cell morphology, the collagen network microstructure, and proliferation. Breast cancer cells remained viable after aspiration-ejection, proliferating slightly less than in unaspirated gels. Furthermore, MDA-MB-231 cells appear to partially relax the collagen network and lose alignment 3 days after aspiration. Aspiration-ejection generated aligned, compact collagen network microstructure with immediate cell co-orientation and higher cell number density apparently through purely physical means, though cell-collagen contact guidance and network remodeling influence cell organization and collagen network microstructure during subsequent culture. This study establishes a platform to determine the effects of collagen density and alignment on cancer cell behavior, with translational potential for anticancer drug screening in a biomimetic three-dimensional matrix microenvironment, or implantation in preclinical models.
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Affiliation(s)
- Ruby N Huynh
- Department of Biomedical Engineering, The Catholic University of America, Washington, District of Columbia
| | - Manal Yousof
- Department of Biomedical Engineering, The Catholic University of America, Washington, District of Columbia
| | - Khanh L Ly
- Department of Biomedical Engineering, The Catholic University of America, Washington, District of Columbia
| | - Farai C Gombedza
- Research Service, Veterans Affairs Medical Center, Washington, District of Columbia
| | - Xiaolong Luo
- Department of Mechanical Engineering, The Catholic University of America, Washington, District of Columbia
| | - Bidhan C Bandyopadhyay
- Department of Biomedical Engineering, The Catholic University of America, Washington, District of Columbia.,Research Service, Veterans Affairs Medical Center, Washington, District of Columbia
| | - Christopher B Raub
- Department of Biomedical Engineering, The Catholic University of America, Washington, District of Columbia
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4
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Koudouna E, Mikula E, Brown DJ, Young RD, Quantock AJ, Jester JV. Cell regulation of collagen fibril macrostructure during corneal morphogenesis. Acta Biomater 2018; 79:96-112. [PMID: 30170195 DOI: 10.1016/j.actbio.2018.08.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 08/06/2018] [Accepted: 08/17/2018] [Indexed: 11/26/2022]
Abstract
While tissue form and function is highly dependent upon tissue-specific collagen composition and organization, little is known of the mechanisms controlling the bundling of collagen fibrils into fibers and larger structural designs that lead to the formation of bones, tendons and other tissues. Using the cornea as a model system, our previous 3 dimensional mapping of collagen fiber organization has demonstrated that macrostructural organization of collagen fibers involving interweaving, branching and anastomosing plays a critical role in controlling mechanical stiffness, corneal shape and refractive power. In this work, the cellular and mechanical mechanisms regulating critical events in the assembly of collagen macrostructure are analysed in the developing chicken cornea. We elucidated the temporal events leading to adult corneal structure and determined the effects of intraocular pressure (IOP) on the organization of the collagen macrostructure. Our findings indicate that the complex adult collagen organization begins to appear on embryonic day 10 (E10) after deposition of the primary stroma and full invasion of keratocytes. Importantly, organizational changes in keratocytes appearing at E9 preceded and predicted later changes in collagen organization. Corneal collagen organization remained unaffected when the development of IOP was blocked at E4. These findings support a primary role for keratocytes in controlling stromal organization, mechanical stiffness and corneal shape that are not regulated by the IOP. Our findings also suggest that the avian cornea represents an excellent experimental model for elucidating key regulatory steps and mechanisms controlling the collagen fiber organization that is critical to determining tissue form and function. STATEMENT OF SIGNIFICANCE This work by using an ex ovo model system, begins to investigate the potential mechanisms controlling collagen fibril macrostructure. In particular, this work highlights a convergent role for the corneal keratocytes in organizing the complex collagen macrostructure, necessary to support high visual acuity. Our data supports that the intraocular pressure does not influence collagen fibril macrostructure and suggest that the avian cornea represents an excellent experimental model for elucidating key regulatory steps and mechanisms controlling the collagen fiber organization that is critical to determining tissue form and function. Clearly understanding the cellular and molecular mechanisms that underlie collagen fibril macrostructure will be highly beneficial for future tissue engineering and regenerative medicine applications.
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5
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Kivanany PB, Grose KC, Yonet-Tanyeri N, Manohar S, Sunkara Y, Lam KH, Schmidtke DW, Varner VD, Petroll WM. An In Vitro Model for Assessing Corneal Keratocyte Spreading and Migration on Aligned Fibrillar Collagen. J Funct Biomater 2018; 9:jfb9040054. [PMID: 30248890 PMCID: PMC6306816 DOI: 10.3390/jfb9040054] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 09/16/2018] [Accepted: 09/18/2018] [Indexed: 01/31/2023] Open
Abstract
Background: Corneal stromal cells (keratocytes) are responsible for developing and maintaining normal corneal structure and transparency, and for repairing the tissue after injury. Corneal keratocytes reside between highly aligned collagen lamellae in vivo. In addition to growth factors and other soluble biochemical factors, feedback from the extracellular matrix (ECM) itself has been shown to modulate corneal keratocyte behavior. Methods: In this study, we fabricate aligned collagen substrates using a microfluidics approach and assess their impact on corneal keratocyte morphology, cytoskeletal organization, and patterning after stimulation with platelet derived growth factor (PDGF) or transforming growth factor beta 1 (TGFβ). We also use time-lapse imaging to visualize the dynamic interactions between cells and fibrillar collagen during wound repopulation following an in vitro freeze injury. Results: Significant co-alignment between keratocytes and aligned collagen fibrils was detected, and the degree of cell/ECM co-alignment further increased in the presence of PDGF or TGFβ. Freeze injury produced an area of cell death without disrupting the collagen. High magnification, time-lapse differential interference contrast (DIC) imaging allowed cell movement and subcellular interactions with the underlying collagen fibrils to be directly visualized. Conclusions: With continued development, this experimental model could be an important tool for accessing how the integration of multiple biophysical and biochemical signals regulate corneal keratocyte differentiation.
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Affiliation(s)
- Pouriska B Kivanany
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Kyle C Grose
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Nihan Yonet-Tanyeri
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Sujal Manohar
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Yukta Sunkara
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Kevin H Lam
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
| | - David W Schmidtke
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Victor D Varner
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA.
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - W Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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Mukhey D, Phillips JB, Daniels JT, Kureshi AK. Controlling human corneal stromal stem cell contraction to mediate rapid cell and matrix organization of real architecture for 3-dimensional tissue equivalents. Acta Biomater 2018; 67:229-237. [PMID: 29208552 DOI: 10.1016/j.actbio.2017.11.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 11/07/2017] [Accepted: 11/28/2017] [Indexed: 12/13/2022]
Abstract
The architecture of the human corneal stroma consists of a highly organized extracellular matrix (ECM) interspersed with keratocytes. Their progenitor cells; corneal stromal stem cells (CSSC) are located at the periphery, in the limbal stroma. A highly organized corneal ECM is critical for effective transmission of light but this structure may be compromised during injury or disease, resulting in loss of vision. Re-creating normal organization in engineered tissue equivalents for transplantation often involves lengthy culture times that are inappropriate for clinical use or utilisation of synthetic substrates that bring complications such as corneal melting. CSSC have great therapeutic potential owing to their ability to reorganize a disorganized matrix, restoring transparency in scarred corneas. We examined CSSC contractile behavior to assess whether this property could be exploited to rapidly generate cell and ECM organization in Real Architecture For 3D Tissues (RAFT) tissue equivalents (TE) for transplantation. Free-floating collagen gels were characterized to assess contractile behavior of CSSC and establish optimum cell density and culture times. To mediate cell and collagen organization, tethered collagen gels seeded with CSSC were cultured and subsequently stabilized with the RAFT process. We demonstrated rapid creation of biomimetic RAFT TE with tunable structural properties. These displayed three distinct regions of varying degrees of cellular and collagen organization. Interestingly, increased organization coincided with a dramatic loss of PAX6 expression in CSSC, indicating rapid differentiation into keratocytes. The organized RAFT TE system could be a useful bioengineering tool to rapidly create an organized ECM while simultaneously controlling cell phenotype. STATEMENT OF SIGNIFICANCE For the first time, we have demonstrated that human CSSC exhibit the phenomenon of cellular self-alignment in tethered collagen gels. We found this mediated rapid co-alignment of collagen fibrils and thus subsequently exploited this property in vitro to improve the architecture of engineered RAFT tissue equivalents of the corneal stroma. Existing techniques are extremely lengthy and carry significant risk and cost for GMP manufacture. This rapid and tunable technique takes just 8 h of culture and is therefore ideal for clinical manufacture, creating biomimetic tissue equivalents with both cellular and ECM organization. Thus, cellular self-alignment can be a useful bioengineering tool for the development of organized tissue equivalents in a variety of applications.
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7
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Ismail EN, Ruberti JW, Malek G. Quick-freeze/deep-etch electron microscopy visualization of the mouse posterior pole. Exp Eye Res 2017. [PMID: 28629927 DOI: 10.1016/j.exer.2017.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The mouse is one of the most commonly used mammalian systems to study human diseases. In particular it has been an invaluable tool to model a multitude of ocular pathologies affecting the posterior pole. The aim of this study was to create a comprehensive map of the ultrastructure of the mouse posterior pole using the quick-freeze/deep-etch method (QFDE). QFDE can produce detailed three-dimensional images of tissue structure and macromolecular moieties, without many of the artifacts introduced by structure-altering post-processing methods necessary to perform conventional transmission electron microscopy (cTEM). A total of 18 eyes from aged C57BL6/J mice were enucleated and the posterior poles were processed, either intact or with the retinal pigment epithelium (RPE) cell layer removed, for imaging by either QFDE or cTEM. QFDE images were correlated with cTEM cross-sections and en face images through the outer retina. Nicely preserved outer retinal architecture was observed with both methods, however, QFDE provided excellent high magnification imaging, with greater detail, of the apical, central, and basal planes of the RPE. Furthermore, key landmarks within Bruch's membrane, choriocapillaris, choroid and sclera were characterized and identified. In this study we developed methods for preparing the outer retina of the mouse for evaluation with QFDE and provide a map of the ultrastructure and cellular composition of the outer posterior pole. This technique should be applicable for morphological evaluation of mouse models, in which detailed visualization of subtle ocular structural changes is needed or in cases where post-processing methods introduce unacceptable artifacts.
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Affiliation(s)
- Ebraheim N Ismail
- Department of Bioengineering, Northeastern University, Boston, MA, United States
| | - Jeffrey W Ruberti
- Department of Bioengineering, Northeastern University, Boston, MA, United States; Schepens Eye Research Institute, Massachusetts Eye and Ear, Boston, MA, United States.
| | - Goldis Malek
- Departments of Ophthalmology and Pathology, Duke University School of Medicine, Durham, NC, United States.
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8
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Kivanany PB, Grose KC, Petroll WM. Temporal and spatial analysis of stromal cell and extracellular matrix patterning following lamellar keratectomy. Exp Eye Res 2016; 153:56-64. [PMID: 27732879 PMCID: PMC5121062 DOI: 10.1016/j.exer.2016.10.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 09/22/2016] [Accepted: 10/07/2016] [Indexed: 01/19/2023]
Abstract
Extracellular matrix (ECM) supplies both physical and chemical signals to keratocytes which can impact their differentiation to fibroblasts and/or myofibroblasts. It also provides a substrate through which they migrate during wound repair. We have previously shown that following transcorneal freeze injury (FI), migrating corneal fibroblasts align parallel to the stromal lamellae during wound repopulation. In this study, we compare cell and ECM patterning both within and on top of the stroma at different time points following lamellar keratectomy (LK) in the rabbit. Twelve rabbits received LK in one eye. Rabbits were monitored using in vivo confocal microscopy at 3, 7, 21 and 60 days after injury. A subset of animals was sacrificed at each time point to further investigate cell and matrix patterning. Tissue was fixed and labeled in situ with Alexa Fluor 488 phalloidin (for F-actin), and imaged using multiphoton fluorescence and second harmonic generation (SHG) imaging (for collagen). Immediately following LK, cell death occurred in the corneal stroma directly beneath the injury. At 7 and 21 days after LK, analysis of fluorescence (F-actin) and SHG results (collagen) indicated that fibroblasts were co-aligned with the collagen lamellae within this region. In contrast, stromal cells accumulating on top of the stromal wound bed were randomly arranged, contained more prominent stress fibers, and expressed alpha smooth muscle actin (α-SMA) and fibronectin. At 60 days, cells and matrix in this region had become co-aligned into lamellar-like structures; cells were elongated but did not express stress fibers. Corneal haze measured using in vivo confocal microscopy peaked at 21 days after LK, and was significantly reduced by 60 days. Cell morphology and patterning observed in vivo was similar to that observed in situ. Our results suggest that the topography and alignment of the collagen lamellae direct fibroblast patterning during repopulation of the native stroma after LK injury in the rabbit. In contrast, stromal cells accumulating on top of the stromal wound bed initially align randomly and produce a fibrotic ECM. Remarkably, over time, these cells appear to remodel the ECM to produce a lamellar structure that is similar to the native corneal stroma.
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Affiliation(s)
- Pouriska B Kivanany
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, United States; Biomedical Engineering Graduate Program, UT Southwestern Medical Center, Dallas, TX, United States
| | - Kyle C Grose
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, United States
| | - W Matthew Petroll
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, United States; Biomedical Engineering Graduate Program, UT Southwestern Medical Center, Dallas, TX, United States.
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Zareian R, Susilo ME, Paten JA, McLean JP, Hollmann J, Karamichos D, Messer CS, Tambe DT, Saeidi N, Zieske JD, Ruberti JW. Human Corneal Fibroblast Pattern Evolution and Matrix Synthesis on Mechanically Biased Substrates. Tissue Eng Part A 2016; 22:1204-1217. [PMID: 27600605 PMCID: PMC5073220 DOI: 10.1089/ten.tea.2016.0164] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Accepted: 08/29/2016] [Indexed: 02/01/2023] Open
Abstract
In a fibroblast colony model of corneal stromal development, we asked how physiological tension influences the patterning dynamics of fibroblasts and the orientation of deposited extracellular matrix (ECM). Using long-term live-cell microscopy, enabled by an optically accessible mechanobioreactor, a primary human corneal fibroblast colony was cultured on three types of substrates: a mechanically biased, loaded, dense, disorganized collagen substrate (LDDCS), a glass coverslip, and an unloaded, dense, disorganized collagen substrate (UDDCS). On LDDCS, fibroblast orientation and migration along a preferred angle developed early, cell orientation was correlated over long distances, and the colony pattern was stable. On glass, fibroblast orientation was poorly correlated, developed more slowly, and colony patterns were metastable. On UDDCS, cell orientation was correlated over shorter distances compared with LDDCS specimens. On all substrates, the ECM pattern reflected the cell pattern. In summary, mechanically biasing the collagen substrate altered the early migration behavior of individual cells, leading to stable emergent cell patterning, which set the template for newly synthesized ECM.
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Affiliation(s)
- Ramin Zareian
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - Monica E. Susilo
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - Jeffrey A. Paten
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - James P. McLean
- Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts
| | - Joseph Hollmann
- The Institute of Photonic Sciences, Castelldefels (Barcelona), Spain
| | - Dimitrios Karamichos
- Department of Ophthalmology, Dean McGee Eye Institute, Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Conor S. Messer
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
| | - Dhananjay T. Tambe
- Departments of Mechanical Engineering and Department of Pharmacology and Center for Lung Biology, University of South Alabama, Mobile, Alabama
| | - Nima Saeidi
- Department of Surgery, Harvard Medical School, Boston, Massachusetts
| | | | - Jeffrey W. Ruberti
- Department of Bioengineering, Northeastern University, Boston, Massachusetts
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Paten JA, Siadat SM, Susilo ME, Ismail EN, Stoner JL, Rothstein JP, Ruberti JW. Flow-Induced Crystallization of Collagen: A Potentially Critical Mechanism in Early Tissue Formation. ACS NANO 2016; 10:5027-40. [PMID: 27070851 PMCID: PMC6037489 DOI: 10.1021/acsnano.5b07756] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The type I collagen monomer is one of nature's most exquisite and prevalent structural tools. Its 300 nm triple-helical motifs assemble into tough extracellular fibers that transition seamlessly across tissue boundaries and exceed cell dimensions by up to 4 orders of magnitude. In spite of extensive investigation, no existing model satisfactorily explains how such continuous structures are generated and grown precisely where they are needed (aligned in the path of force) by discrete, microscale cells using materials with nanoscale dimensions. We present a simple fiber drawing experiment, which demonstrates that slightly concentrated type I collagen monomers can be "flow-crystallized" to form highly oriented, continuous, hierarchical fibers at cell-achievable strain rates (<1 s(-1)) and physiologically relevant concentrations (∼50 μM). We also show that application of tension following the drawing process maintains the structural integrity of the fibers. While mechanical tension has been shown to be a critical factor driving collagen fibril formation during tissue morphogenesis in developing animals, the precise role of force in the process of building tissue is not well understood. Our data directly couple mechanical tension, specifically the extensional strain rate, to collagen fibril assembly. We further derive a "growth equation" which predicts that application of extensional strains, either globally by developing muscles or locally by fibroblasts, can rapidly drive the fusion of already formed short fibrils to produce long-range, continuous fibers. The results provide a pathway to scalable connective tissue manufacturing and support a mechano-biological model of collagen fibril deposition and growth in vivo.
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Affiliation(s)
- Jeffrey A Paten
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Seyed Mohammad Siadat
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Monica E Susilo
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Ebraheim N Ismail
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Jayson L Stoner
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Jonathan P Rothstein
- Department of Mechanical and Industrial Engineering, University of Massachusetts Amherst , 160 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Jeffrey W Ruberti
- Department of Bioengineering, Northeastern University , 360 Huntington Avenue, Boston, Massachusetts 02115, United States
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11
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Metabolic profiling during ex vivo machine perfusion of the human liver. Sci Rep 2016; 6:22415. [PMID: 26935866 PMCID: PMC4776101 DOI: 10.1038/srep22415] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 02/15/2016] [Indexed: 01/12/2023] Open
Abstract
As donor organ shortages persist, functional machine perfusion is under investigation to improve preservation of the donor liver. The transplantation of donation after circulatory death (DCD) livers is limited by poor outcomes, but its application may be expanded by ex vivo repair and assessment of the organ before transplantation. Here we employed subnormothermic (21 °C) machine perfusion of discarded human livers combined with metabolomics to gain insight into metabolic recovery during machine perfusion. Improvements in energetic cofactors and redox shifts were observed, as well as reversal of ischemia-induced alterations in selected pathways, including lactate metabolism and increased TCA cycle intermediates. We next evaluated whether DCD livers with steatotic and severe ischemic injury could be discriminated from ‘transplantable’ DCD livers. Metabolomic profiling was able to cluster livers with similar metabolic patterns based on the degree of injury. Moreover, perfusion parameters combined with differences in metabolic factors suggest variable mechanisms that result in poor energy recovery in injured livers. We conclude that machine perfusion combined with metabolomics has significant potential as a clinical instrument for the assessment of preserved livers.
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12
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Leferink AM, van Blitterswijk CA, Moroni L. Methods of Monitoring Cell Fate and Tissue Growth in Three-Dimensional Scaffold-Based Strategies for In Vitro Tissue Engineering. TISSUE ENGINEERING PART B-REVIEWS 2016; 22:265-83. [PMID: 26825610 DOI: 10.1089/ten.teb.2015.0340] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
In the field of tissue engineering, there is a need for methods that allow assessing the performance of tissue-engineered constructs noninvasively in vitro and in vivo. To date, histological analysis is the golden standard to retrieve information on tissue growth, cellular distribution, and cell fate on tissue-engineered constructs after in vitro cell culture or on explanted specimens after in vivo applications. Yet, many advances have been made to optimize imaging techniques for monitoring tissue-engineered constructs with a sub-mm or μm resolution. Many imaging modalities have first been developed for clinical applications, in which a high penetration depth has been often more important than lateral resolution. In this study, we have reviewed the current state of the art in several imaging approaches that have shown to be promising in monitoring cell fate and tissue growth upon in vitro culture. Depending on the aimed tissue type and scaffold properties, some imaging methods are more applicable than others. Optical methods are mostly suited for transparent materials such as hydrogels, whereas magnetic resonance-based methods are mostly applied to obtain contrast between hard and soft tissues regardless of their transparency. Overall, this review shows that the field of imaging in scaffold-based tissue engineering is developing at a fast pace and has the potential to overcome the limitations of destructive endpoint analysis.
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Affiliation(s)
- Anne M Leferink
- 1 Department of Tissue Regeneration, MIRA Institute, University of Twente , Enschede, The Netherlands .,2 Department of Complex Tissue Regeneration, Maastricht University , Maastricht, The Netherlands .,3 BIOS/Lab-on-a-chip Group, MIRA Institute, University of Twente , Enschede, The Netherlands
| | - Clemens A van Blitterswijk
- 1 Department of Tissue Regeneration, MIRA Institute, University of Twente , Enschede, The Netherlands .,2 Department of Complex Tissue Regeneration, Maastricht University , Maastricht, The Netherlands
| | - Lorenzo Moroni
- 1 Department of Tissue Regeneration, MIRA Institute, University of Twente , Enschede, The Netherlands .,2 Department of Complex Tissue Regeneration, Maastricht University , Maastricht, The Netherlands
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13
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Petroll WM, Kivanany PB, Hagenasr D, Graham EK. Corneal Fibroblast Migration Patterns During Intrastromal Wound Healing Correlate With ECM Structure and Alignment. Invest Ophthalmol Vis Sci 2015; 56:7352-61. [PMID: 26562169 PMCID: PMC4645812 DOI: 10.1167/iovs.15-17978] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 10/14/2015] [Indexed: 12/11/2022] Open
Abstract
PURPOSE To assess keratocyte backscattering, alignment, morphology, and connectivity in vivo following a full-thickness corneal injury using the Heidelberg Retina Tomograph Rostock Cornea Module (HRT-RCM), and to correlate these findings with en bloc three-dimensional (3-D) confocal fluorescence and second harmonic generation (SHG) imaging. METHODS Rabbit corneas were scanned in vivo both before and 3, 7, 14, and 28 days after transcorneal freeze injury (FI), which damages all corneal cell layers. Corneal tissue was also fixed and labeled for f-actin and nuclei en bloc, and imaged using 3-D confocal fluorescence microscopy and SHG imaging. RESULTS Using the modified HRT-RCM, full-thickness scans of all cell layers were consistently obtained. Following FI, stromal cells repopulating the damaged tissue assumed an elongated fibroblastic morphology, and a significant increase in cellular light scattering was measured. This stromal haze gradually decreased as wound healing progressed. Parallel, interconnected streams of aligned corneal fibroblasts were observed both in vivo (from HRT-RCM reflection images) and ex vivo (from f-actin and nuclear labeling) during wound healing, particularly in the posterior cornea. Second harmonic generation imaging demonstrated that these cells were aligned parallel to the collagen lamellae. CONCLUSIONS The modified HRT-RCM allows in vivo measurements of sublayer thickness, assessment of cell morphology, alignment and connectivity, and estimation of stromal backscatter during wound healing. In this study, these in vivo observations led to the novel finding that the pattern of corneal fibroblast alignment is highly correlated with lamellar organization, suggesting contact guidance of intrastromal migration that may facilitate more rapid wound repopulation.
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Affiliation(s)
- W. Matthew Petroll
- Department of Ophthalmology University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Pouriska B. Kivanany
- Department of Ophthalmology University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Daniela Hagenasr
- Department of Ophthalmology University of Texas Southwestern Medical Center, Dallas, Texas, United States
| | - Eric K. Graham
- Department of Ophthalmology University of Texas Southwestern Medical Center, Dallas, Texas, United States
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14
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Hertsenberg AJ, Funderburgh JL. Stem Cells in the Cornea. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2015; 134:25-41. [PMID: 26310147 DOI: 10.1016/bs.pmbts.2015.04.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The cornea is the tough, transparent tissue through which light first enters the eye and functions as a barrier to debris and infection as well as two-thirds of the refractive power of the eye. Corneal damage that is not promptly treated will often lead to scarring and vision impairment. Due to the limited options currently available to treat corneal scars, the identification and isolation of stem cells in the cornea has received much attention, as they may have potential for autologous, cell-based approaches to the treatment of damaged corneal tissue.
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Affiliation(s)
- Andrew J Hertsenberg
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - James L Funderburgh
- Department of Ophthalmology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA.
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15
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Petroll WM, Miron-Mendoza M. Mechanical interactions and crosstalk between corneal keratocytes and the extracellular matrix. Exp Eye Res 2015; 133:49-57. [PMID: 25819454 PMCID: PMC4379425 DOI: 10.1016/j.exer.2014.09.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/09/2014] [Accepted: 09/11/2014] [Indexed: 12/13/2022]
Abstract
The generation of cellular forces and the application of these physical forces to the ECM play a central role in mediating matrix patterning and remodeling during fundamental processes such as developmental morphogenesis and wound healing. In addition to growth factors and other biochemical factors that can modulate the keratocyte mechanical phenotype, another key player in the regulation of cell-induced ECM patterning is the mechanical state of the ECM itself. In this review we provide an overview of the biochemical and biophysical factors regulating the mechanical interactions between corneal keratocytes and the stromal ECM at the cellular level. We first provide an overview of how Rho GTPases regulate the sub-cellular pattern of force generation by corneal keratocytes, and the impact these forces have on the surrounding ECM. We next review how feedback from local matrix structural and mechanical properties can modulate keratocyte phenotype and mechanical activity. Throughout this review, we provide examples of how these biophysical interactions may contribute to clinical outcomes, with a focus on corneal wound healing.
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Affiliation(s)
- W Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9057, USA.
| | - Miguel Miron-Mendoza
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9057, USA
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16
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A microfabricated, optically accessible device to study the effects of mechanical cues on collagen fiber organization. Biomed Microdevices 2014; 16:255-67. [PMID: 24390073 DOI: 10.1007/s10544-013-9829-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
As the primary structural protein of our bodies, fibrillar collagen and its organizational patterns determine the biomechanics and shape of tissues. While the molecular assembly of individual fibrils is well understood, the mechanisms determining the arrangement of fibers and thus the shape and form of tissues remain largely unknown. We have developed a cell culture model that successfully recapitulates early tissue development and the de novo deposition of collagen fibers to investigate the role of mechanical cues on collagen fiber alignment. The devices used a thin, collagen-coated deformable PDMS membrane inside a tissue culture well built on microscope-grade coverslips. Deformations and strains in the PDMS membrane were quantified by tracking fluorescent bead displacement and through the use of a COMSOL model. Cyclical strains were applied to serum-cultured rabbit corneal cells at 0.5 Hz for 24-48 h and showed a preferred alignment after 36 h of cyclical loading. Cells cultured with ascorbic acid under methylcellulose serum-free conditions deposited a collagenous matrix that was visible under live second harmonic generation microscopy at week 4. Our microfabricated tissue culture system allows for the controllable application of a wide range of stress profiles to cells, and for the observation and quantification of cells and de novo collagen formation in vitro. Future studies will involve the fabrication of models to study the formation and organization of collagen in ocular diseases.
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17
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Breidenbach AP, Dyment NA, Lu Y, Rao M, Shearn JT, Rowe DW, Kadler KE, Butler DL. Fibrin gels exhibit improved biological, structural, and mechanical properties compared with collagen gels in cell-based tendon tissue-engineered constructs. Tissue Eng Part A 2014; 21:438-50. [PMID: 25266738 DOI: 10.1089/ten.tea.2013.0768] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The prevalence of tendon and ligament injuries and inadequacies of current treatments is driving the need for alternative strategies such as tissue engineering. Fibrin and collagen biopolymers have been popular materials for creating tissue-engineered constructs (TECs), as they exhibit advantages of biocompatibility and flexibility in construct design. Unfortunately, a few studies have directly compared these materials for tendon and ligament applications. Therefore, this study aims at determining how collagen versus fibrin hydrogels affect the biological, structural, and mechanical properties of TECs during formation in vitro. Our findings show that tendon and ligament progenitor cells seeded in fibrin constructs exhibit improved tenogenic gene expression patterns compared with their collagen-based counterparts for approximately 14 days in culture. Fibrin-based constructs also exhibit improved cell-derived collagen alignment, increased linear modulus (2.2-fold greater) compared with collagen-based constructs. Cyclic tensile loading, which promotes the maturation of tendon constructs in a previous work, exhibits a material-dependent effect in this study. Fibrin constructs show trending reductions in mechanical, biological, and structural properties, whereas collagen constructs only show improved tenogenic expression in the presence of mechanical stimulation. These findings highlight that components of the mechanical stimulus (e.g., strain amplitude or time of initiation) need to be tailored to the material and cell type. Given the improvements in tenogenic expression, extracellular matrix organization, and material properties during static culture, in vitro findings presented here suggest that fibrin-based constructs may be a more suitable alternative to collagen-based constructs for tissue-engineered tendon/ligament repair.
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Affiliation(s)
- Andrew P Breidenbach
- 1 Biomedical Engineering Program, Department of Biomedical, Chemical and Environmental Engineering, College of Engineering and Applied Science, University of Cincinnati , Cincinnati, Ohio
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18
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Stepp MA, Zieske JD, Trinkaus-Randall V, Kyne BM, Pal-Ghosh S, Tadvalkar G, Pajoohesh-Ganji A. Wounding the cornea to learn how it heals. Exp Eye Res 2014; 121:178-93. [PMID: 24607489 DOI: 10.1016/j.exer.2014.02.007] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2014] [Revised: 02/07/2014] [Accepted: 02/10/2014] [Indexed: 12/12/2022]
Abstract
Corneal wound healing studies have a long history and rich literature that describes the data obtained over the past 70 years using many different species of animals and methods of injury. These studies have lead to reduced suffering and provided clues to treatments that are now helping patients live more productive lives. In spite of the progress made, further research is required since blindness and reduced quality of life due to corneal scarring still happens. The purpose of this review is to summarize what is known about different types of wound and animal models used to study corneal wound healing. The subject of corneal wound healing is broad and includes chemical and mechanical wound models. This review focuses on mechanical injury models involving debridement and keratectomy wounds to reflect the authors' expertise.
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Affiliation(s)
- Mary Ann Stepp
- Department of Anatomy and Regenerative Biology, The George Washington University Medical Center, Washington, DC 20037, USA; Department of Ophthalmology, The George Washington University Medical Center, Washington, DC 20037, USA.
| | - James D Zieske
- Department of Ophthalmology, Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA 02114-2500, USA
| | - Vickery Trinkaus-Randall
- Department of Ophthalmology, Boston University School of Medicine, Boston, MA 02118, USA; Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA
| | - Briana M Kyne
- Department of Anatomy and Regenerative Biology, The George Washington University Medical Center, Washington, DC 20037, USA
| | - Sonali Pal-Ghosh
- Department of Anatomy and Regenerative Biology, The George Washington University Medical Center, Washington, DC 20037, USA
| | - Gauri Tadvalkar
- Department of Anatomy and Regenerative Biology, The George Washington University Medical Center, Washington, DC 20037, USA
| | - Ahdeah Pajoohesh-Ganji
- Department of Anatomy and Regenerative Biology, The George Washington University Medical Center, Washington, DC 20037, USA
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19
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Oryan A, Moshiri A, Meimandi-Parizi A. In vitro characterization of a novel tissue engineered based hybridized nano and micro structured collagen implant and its in vivo role on tenoinduction, tenoconduction, tenogenesis and tenointegration. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2014; 25:873-897. [PMID: 24327109 DOI: 10.1007/s10856-013-5110-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 11/29/2013] [Indexed: 06/03/2023]
Abstract
Surgical reconstruction of large tendon defects is technically demanding. Tissue engineering is a new option. We produced a novel tissue engineered, collagen based, bioimplant and in vitro characterizations of the implant were investigated. In addition, we investigated role of the collagen implant on the healing of a large tendon defect model in rabbits. A two cm length of the left rabbit's Achilles tendon was transected and discarded. The injured tendons of all the rabbits were repaired by Kessler pattern to create and maintain a 2 cm tendon gap. The collagen implant was inserted in the tendon defect of the treatment group (n = 30). The defect area was left intact in the control group (n = 30). The animals were euthanized at 60 days post injury (DPI) and the macro- micro- and nano- morphologies and the biomechanical characteristics of the tendon samples were studied. Differences of P < 0.05 were considered significant. The host graft interaction was followed at various stages of tendon healing, using pilot animals. At 60 DPI, a significant increase in number, diameter and density of the collagen fibrils, number and maturity of tenoblasts and tenocytes, alignment of the collagen fibrils and maturity of the elastic fibers were seen in the treated tendons when compared to the control ones (P < 0.05). Compared to the control lesions, number of inflammatory cells, amount of peritendinous adhesions and muscle fibrosis and atrophy, were significantly lower in the treated lesions (P < 0.05). Treatment also significantly increased load to failure, tensile strength and elastic modulus of the samples as compared with the control ones. The collagen implant properly incorporated with the healing tissue and was replaced by the new tendinous structure which was superior both ultra-structurally and physically than the loose areolar connective tissue regenerated in the control lesions. The results of this study may be valuable in the clinical practice.
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Affiliation(s)
- Ahmad Oryan
- Department of Pathology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
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20
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Wu J, Du Y, Mann MM, Funderburgh JL, Wagner WR. Corneal stromal stem cells versus corneal fibroblasts in generating structurally appropriate corneal stromal tissue. Exp Eye Res 2014; 120:71-81. [PMID: 24440595 PMCID: PMC3979324 DOI: 10.1016/j.exer.2014.01.005] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2013] [Revised: 01/03/2014] [Accepted: 01/04/2014] [Indexed: 12/13/2022]
Abstract
Recapitulation of human corneal stromal tissue is believed to be among the most challenging steps in engineering human corneal tissue because of the difficulty in reproducing its highly-ordered hierarchical ultrastructure, which imparts its robust biomechanical properties and optical transparency. In this study, we compared the feasibility of utilizing human corneal stromal stem cells (hCSSCs) and human corneal fibroblasts (hCFs) in the generation of human corneal stromal tissue on a highly-aligned fibrous substrate made from poly(ester urethane) urea. In the serum-free keratocyte differentiation medium supplemented with FGF-2 (10 ng/mL) and TGF-β3 (0.1 ng/mL), hCSSCs successfully differentiated into keratocytes and secreted multilayered lamellae with orthogonally-oriented collagen fibrils, in a pattern mimicking human corneal stromal tissue. The constructs were 60-70 μm thick and abundant in cornea-specific extracellular matrix (ECM) components, including keratan sulfate, lumican, and keratocan. Under the identical conditions, hCFs tended to differentiate into myofibroblasts and deposited a less-organized collagen-fibrillar construct in a pattern with similarities to corneal scar tissue due to a lack of cornea-specific ECM components. These observations demonstrated that hCSSCs showed a much greater potential, under proper substrate and growth factor guidance, to facilitate the generation of a biological human cornea equivalent. Unlike hCSSCs, hCFs were less responsive to these environmental cues and under identical culture conditions generated an ECM that poorly mimicked the native, functional tissue structure and composition.
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Affiliation(s)
- Jian Wu
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive, Suite 300, Pittsburgh, PA 15219, USA; Department of Surgery, University of Pittsburgh, School of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213, USA
| | - Yiqin Du
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive, Suite 300, Pittsburgh, PA 15219, USA; Department of Ophthalmology, University of Pittsburgh, School of Medicine, 203 Lothrop Street, Pittsburgh, PA 15213, USA
| | - Mary M Mann
- Department of Ophthalmology, University of Pittsburgh, School of Medicine, 203 Lothrop Street, Pittsburgh, PA 15213, USA
| | - James L Funderburgh
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive, Suite 300, Pittsburgh, PA 15219, USA; Department of Ophthalmology, University of Pittsburgh, School of Medicine, 203 Lothrop Street, Pittsburgh, PA 15213, USA
| | - William R Wagner
- McGowan Institute for Regenerative Medicine, University of Pittsburgh, 450 Technology Drive, Suite 300, Pittsburgh, PA 15219, USA; Department of Surgery, University of Pittsburgh, School of Medicine, 200 Lothrop Street, Pittsburgh, PA 15213, USA; Department of Bioengineering, University of Pittsburgh, 300 Technology Drive, Pittsburgh, PA 15219, USA.
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21
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Oryan A, Moshiri A, Parizi AM, Maffulli N. Implantation of a novel biologic and hybridized tissue engineered bioimplant in large tendon defect: an in vivo investigation. Tissue Eng Part A 2013; 20:447-65. [PMID: 24004331 DOI: 10.1089/ten.tea.2013.0053] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Surgical reconstruction of large Achilles tendon defects is technically demanding. There is no standard method, and tissue engineering may be a valuable option. We investigated the effects of 3D collagen and collagen-polydioxanone sheath (PDS) implants on a large tendon defect model in rabbits. Ninety rabbits were divided into three groups: control, collagen, and collagen-PDS. In all groups, 2 cm of the left Achilles tendon were excised and discarded. A modified Kessler suture was applied to all injured tendons to retain the gap length. The control group received no graft, the treated groups were repaired using the collagen only or the collagen-PDS prostheses. The bioelectrical characteristics of the injured areas were measured at weekly intervals. The animals were euthanized at 60 days after the procedure. Gross, histopathological and ultrastructural morphology and biophysical characteristics of the injured and intact tendons were investigated. Another 90 pilot animals were also used to investigate the inflammatory response and mechanism of graft incorporation during tendon healing. The control tendons showed severe hyperemia and peritendinous adhesion, and the gastrocnemius muscle of the control animals showed severe atrophy and fibrosis, with a loose areolar connective tissue filling the injured area. The tendons receiving either collagen or collagen-PDS implants showed lower amounts of peritendinous adhesion, hyperemia and muscle atrophy, and a dense tendon filled the defect area. Compared to the control tendons, application of collagen and collagen-PDS implants significantly improved water uptake, water delivery, direct transitional electrical current and tissue resistance to direct transitional electrical current. Compared to the control tendons, both prostheses showed significantly increased diameter, density and alignment of the collagen fibrils and maturity of the tenoblasts at ultrastructure level. Both prostheses influenced favorably tendon healing compared to the control tendons, with no significant differences between collagen and collagen-PDS groups. Implantation of the 3D collagen and collagen-PDS implants accelerated the production of a new tendon in the defect area, and may become a valuable option in clinical practice.
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Affiliation(s)
- Ahmad Oryan
- 1 Department of Pathology, School of Veterinary Medicine, Shiraz University , Shiraz, Iran
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22
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Meimandi-Parizi A, Oryan A, Moshiri A. Tendon tissue engineering and its role on healing of the experimentally induced large tendon defect model in rabbits: a comprehensive in vivo study. PLoS One 2013; 8:e73016. [PMID: 24039851 PMCID: PMC3764104 DOI: 10.1371/journal.pone.0073016] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Accepted: 07/19/2013] [Indexed: 01/01/2023] Open
Abstract
Healing of large tendon defects is challenging. We studied the role of collagen implant with or without polydioxanone (PDS) sheath on the healing of a large Achilles tendon defect model, in rabbits. Sixty rabbits were divided into three groups. A 2 cm gap was created in the left Achilles tendon of all rabbits. In the control lesions, no implant was used. The other two groups were reconstructed by collagen and collagen-PDS implants respectively. The animals were clinically examined at weekly intervals and their lesions were observed by ultrasonography. Blood samples were obtained from the animals and were assessed for hematological analysis and determination of serum PDGF level, at 60 days post injury (DPI). The animals were then euthanized and their lesions were assessed for gross and histopathology, scanning electron microscopy, biomechanical testing, dry matter and hydroxyproline content. Another 65 pilot animals were also studied grossly and histopathologically to define the host implant interaction and graft incorporation at serial time points. The treated animals gained significantly better clinical scoring compared to the controls. Treatment with collagen and collagen-PDS implants significantly increased the biomechanical properties of the lesions compared to the control tendons at 60DPI (P<0.05). The tissue engineered implants also reduced peritendinous adhesion, muscle fibrosis and atrophy, and increased ultrasonographical echogenicity and homogenicity, maturation and differentiation of the collagen fibrils and fibers, tissue alignment and volume of the regenerated tissue compared to those of the control lesions (P<0.05). The implants were gradually absorbed and substituted by the new tendon. Implantation of the bioimplants had a significant role in initiating tendon healing and the implants were biocompatible, biodegradable and safe for application in tendon reconstructive surgery. The results of the present study may be valuable in clinical practice.
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Affiliation(s)
- Abdolhamid Meimandi-Parizi
- Division of Surgery, Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
- * E-mail:
| | - Ahmad Oryan
- Department of Pathology, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
| | - Ali Moshiri
- Division of Surgery, Department of Clinical Sciences, School of Veterinary Medicine, Shiraz University, Shiraz, Iran
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23
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Novel application of a tissue-engineered collagen-based three-dimensional bio-implant in a large tendon defect model: a broad-based study with high value in translational medicine. Tissue Cell 2013; 45:282-94. [PMID: 23627994 DOI: 10.1016/j.tice.2013.03.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2012] [Revised: 03/27/2013] [Accepted: 03/27/2013] [Indexed: 11/21/2022]
Abstract
This study was designed to investigate the effectiveness of a novel tissue-engineered three-dimensional collagen implant on healing of a large tendon-defect model, in vivo. Forty rabbits were divided into two equal groups: treated and control. A 2cm full-thickness gap was created in the left Achilles tendons of all the rabbits. To maintain the gap at the desired length (2cm), a Kessler suture was anchored within the proximal and distal ends of the remaining tendon. In the treated group a collagen implant was inserted in the gap while in the control group the gap was left unfilled. At weekly intervals the animals were examined clinically and their Achilles tendons tested bioelectrically. The hematological parameters and the serum Platelet-Derived Growth Factor of the animals were analyzed at 60 days post injury (DPI) immediately prior to euthanasia. Their injured (left) and normal contralateral Achilles tendons were harvested and examined at gross morphologic level before being subjected to biomechanical testing, and biophysical and biochemical analysis. The treated animals showed superior weight-bearing and greater physical activity than their controls. New dense tendinous tissue with a transverse diameter comparable to that of intact tendons filled the defect area of the treated tendons and had entirely replaced the collagen implant, at 60 DPI. In control lesions the defect was filled with loose areolar connective tissue similar to subcutaneous fascia. Treatment significantly improved the electrical resistance, dry matter, hydroxyproline content, water uptake and water delivery characteristics, of the healing tissue, as well as maximum load, yield load, maximum stress, yield stress and modulus of elasticity of the injured treated tendons compared to those of the control tendons (P<0.05). Use of this three-dimensional collagen implant improved the healing of large tendon defects in rabbits.
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24
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Hadidi P, Athanasiou KA. Enhancing the mechanical properties of engineered tissue through matrix remodeling via the signaling phospholipid lysophosphatidic acid. Biochem Biophys Res Commun 2013; 433:133-8. [PMID: 23458458 DOI: 10.1016/j.bbrc.2013.02.048] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 02/10/2013] [Indexed: 02/07/2023]
Abstract
Knee meniscus fibrocartilage is frequently injured, resulting in approximately 1 million procedures annually in the US and Europe. Its near-avascularity contributes heavily to its inability to heal, and places it as a prime candidate for replacement through regenerative medicine. Here, we describe a novel approach to increase extracellular matrix organization, rather than content, in order to augment the mechanical properties of engineered tissue. To synthesize fibrocartilage, we employ a self-assembling process, which is free of exogenous scaffolds and relies on cell-to-cell interactions to form all-biologic constructs. When treated with the signaling phospholipid lysophosphatidic acid (LPA), tissue constructs displayed increased tensile properties and collagen organization, while total collagen content remained unchanged. LPA-treated constructs exhibited greater DNA content, indicative that the molecule exerted a signaling effect. Furthermore, LPA-treated cells displayed significant cytoskeletal reorganization. We conclude that LPA induced cytoskeletal reorganization and cell-matrix traction, which resulted in matrix reorganization and increased tensile properties. This study emphasizes the potential of non-traditional stimuli, such as signaling phospholipids, for use in tissue development studies. The extension of these results to other collagen-rich tissues represents a promising avenue for future exploration.
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Affiliation(s)
- Pasha Hadidi
- Department of Biomedical Engineering, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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25
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Saeidi N, Karmelek KP, Paten JA, Zareian R, DiMasi E, Ruberti JW. Molecular crowding of collagen: a pathway to produce highly-organized collagenous structures. Biomaterials 2012; 33:7366-74. [PMID: 22846420 DOI: 10.1016/j.biomaterials.2012.06.041] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2012] [Accepted: 06/22/2012] [Indexed: 12/20/2022]
Abstract
Collagen in vertebrate animals is often arranged in alternating lamellae or in bundles of aligned fibrils which are designed to withstand in vivo mechanical loads. The formation of these organized structures is thought to result from a complex, large-area integration of individual cell motion and locally-controlled synthesis of fibrillar arrays via cell-surface fibripositors (direct matrix printing). The difficulty of reproducing such a process in vitro has prevented tissue engineers from constructing clinically useful load-bearing connective tissue directly from collagen. However, we and others have taken the view that long-range organizational information is potentially encoded into the structure of the collagen molecule itself, allowing the control of fibril organization to extend far from cell (or bounding) surfaces. We here demonstrate a simple, fast, cell-free method capable of producing highly-organized, anistropic collagen fibrillar lamellae de novo which persist over relatively long-distances (tens to hundreds of microns). Our approach to nanoscale organizational control takes advantage of the intrinsic physiochemical properties of collagen molecules by inducing collagen association through molecular crowding and geometric confinement. To mimic biological tissues which comprise planar, aligned collagen lamellae (e.g. cornea, lamellar bone or annulus fibrosus), type I collagen was confined to a thin, planar geometry, concentrated through molecular crowding and polymerized. The resulting fibrillar lamellae show a striking resemblance to native load-bearing lamellae in that the fibrils are small, generally aligned in the plane of the confining space and change direction en masse throughout the thickness of the construct. The process of organizational control is consistent with embryonic development where the bounded planar cell sheets produced by fibroblasts suggest a similar confinement/concentration strategy. Such a simple approach to nanoscale organizational control of structure not only makes de novo tissue engineering a possibility, but also suggests a clearer pathway to organization for fibroblasts than direct matrix printing.
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Affiliation(s)
- Nima Saeidi
- Center for Engineering in Medicine, Harvard Medical School, Massachusetts General Hospital, Boston, MA 02114, USA.
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