scholarly journals Prospects and Challenges of Translational Corneal Bioprinting

2020 ◽  
Vol 7 (3) ◽  
pp. 71 ◽  
Author(s):  
Matthias Fuest ◽  
Gary Hin-Fai Yam ◽  
Jodhbir S. Mehta ◽  
Daniela F. Duarte Campos
Keyword(s):  
Tissue Engineering ◽  
Ex Vivo ◽  
Corneal Transplantation ◽  
Human Cornea ◽  
Corneal Tissue ◽  
Full Thickness ◽  
Future Directions ◽  
Spatial Control

Corneal transplantation remains the ultimate treatment option for advanced stromal and endothelial disorders. Corneal tissue engineering has gained increasing interest in recent years, as it can bypass many complications of conventional corneal transplantation. The human cornea is an ideal organ for tissue engineering, as it is avascular and immune-privileged. Mimicking the complex mechanical properties, the surface curvature, and stromal cytoarchitecure of the in vivo corneal tissue remains a great challenge for tissue engineering approaches. For this reason, automated biofabrication strategies, such as bioprinting, may offer additional spatial control during the manufacturing process to generate full-thickness cell-laden 3D corneal constructs. In this review, we discuss recent advances in bioprinting and biomaterials used for in vitro and ex vivo corneal tissue engineering, corneal cell-biomaterial interactions after bioprinting, and future directions of corneal bioprinting aiming at engineering a full-thickness human cornea in the lab.

Collagen fibrous scaffolds for sustained delivery of growth factors for meniscal tissue engineering

Nanomedicine ◽  
2022 ◽  
Author(s):  
Jihye Baek ◽  
Kwang Il Lee ◽  
Ho Jong Ra ◽  
Martin K Lotz ◽  
Darryl D D'Lima
Keyword(s):  
Tissue Engineering ◽  
Growth Factors ◽  
Sustained Release ◽  
Ex Vivo ◽  
Synovial Cell ◽  
Growth Factor Delivery ◽  
Meniscal Tissue ◽  
A Cell

Aim: To mimic the ultrastructural morphology of the meniscus with nanofiber scaffolds coupled with controlled growth factor delivery to modulate cellular performance for tissue engineering of menisci. Methods: The authors functionalized collagen nanofibers by conjugating heparin to the following growth factors for sustained release: PDGF-BB, TGF-β1 and CTGF. Results: Incorporating growth factors increased human meniscal and synovial cell viability, proliferation and infiltration in vitro, ex vivo and in vivo; upregulated key genes involved in meniscal extracellular matrix synthesis; and enhanced generation of meniscus-like tissue. Conclusion: The authors' results indicate that functionalizing collagen nanofibers can create a cell-favorable micro- and nanoenvironment and can serve as a system for sustained release of bioactive factors.

scholarly journals Effect of Skin Model on In Vitro Performance of an Adhesive Dermally Applied Microarray Coated with Zolmitriptan

2018 ◽  
Vol 2018 ◽  
pp. 1-5 ◽  
Author(s):  
Mahmoud Ameri ◽  
Hayley Lewis ◽  
Paul Lehman
Keyword(s):  
Human Skin ◽  
Ex Vivo ◽  
Full Thickness ◽  
Artificial Membrane ◽  
Skin Model ◽  
Hydrophobic Membrane ◽  
Thickness Skin ◽  
In Vitro Performance

Franz cell studies, utilizing different human skin and an artificial membrane, evaluating the influence of skin model on permeation of zolmitriptan coated on an array of titanium microprojections, were evaluated. Full thickness and dermatomed ex vivo human skin, as well as a synthetic hydrophobic membrane (Strat-M®), were assessed. It was found that the choice of model demonstrated different absorption kinetics for the permeation of zolmitriptan. For the synthetic membrane only 11% of the zolmitriptan coated dose permeated into the receptor media, whilst for the dermatomed skin 85% permeated into the receptor. The permeation of zolmitriptan through full thickness skin had a significantly different absorption profile and time to maximum flux in comparison to the dermatomed skin and synthetic model. On the basis of these results dermatomed skin may be a better estimate of in vivo performance of drug-coated metallic microprojections.

scholarly journals Biomaterials for corneal endothelial cell culture and tissue engineering

2021 ◽  
Vol 12 ◽  
pp. 204173142199053
Author(s):  
Mohit Parekh ◽  
Vito Romano ◽  
Kareem Hassanin ◽  
Valeria Testa ◽  
Rintra Wongvisavavit ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Endothelial Cells ◽  
Standard Treatment ◽  
Corneal Endothelial Cell ◽  
Corneal Tissue ◽  
Corneal Endothelial Cells ◽  
Endothelial Cell Culture ◽  
Corneal Transplants

The corneal endothelium is the posterior monolayer of cells that are responsible for maintaining overall transparency of the avascular corneal tissue via pump function. These cells are non-regenerative in vivo and therefore, approximately 40% of corneal transplants undertaken worldwide are a result of damage or dysfunction of endothelial cells. The number of available corneal donor tissues is limited worldwide, hence, cultivation of human corneal endothelial cells (hCECs) in vitro has been attempted in order to produce tissue engineered corneal endothelial grafts. Researchers have attempted to recreate the current gold standard treatment of replacing the endothelial layer with accompanying Descemet’s membrane or a small portion of stroma as support with tissue engineering strategies using various substrates of both biologically derived and synthetic origin. Here we review the potential biomaterials that are currently in development to support the transplantation of a cultured monolayer of hCECs.

scholarly journals Ex Vivo and In Vivo Properties of an Injectable Hydrogel Derived From Acellular Ear Cartilage Extracellular Matrix

2021 ◽  
Vol 9 ◽  
Author(s):  
Danni Gong ◽  
Fei Yu ◽  
Meng Zhou ◽  
Wei Dong ◽  
Dan Yan ◽  
...  
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Histological Analysis ◽  
Ex Vivo ◽  
Positive Staining ◽  
Gelation Kinetics ◽  
Ear Cartilage ◽  
Kinetics Of

Extracellular matrix (ECM) hydrogels provide advantages such as injectability, the ability to fill an irregularly shaped space, and the adequate bioactivity of native matrix. In this study, we developed decellularized cartilage ECM (dcECM) hydrogels from porcine ears innovatively via the main method of enzymatic digestion and verified good biocompatible properties of dcECM hydrogels to deliver chondrocytes and form subcutaneous cartilage in vivo. The scanning electron microscopy and turbidimetric gelation kinetics were used to characterize the material properties and gelation kinetics of the dcECM hydrogels. Then we evaluated the biocompatibility of hydrogels via the culture of chondrocytes in vitro. To further explore the dcECM hydrogels in vivo, grafts made from the mixture of dcECM hydrogels and chondrocytes were injected subcutaneously in nude mice for the gross and histological analysis. The structural and gelation kinetics of the dcECM hydrogels altered according to the variation in the ECM concentrations. The 10 mg/ml dcECM hydrogels could support the adhesion and proliferation of chondrocytes in vitro. In vivo, at 4 weeks after transplantation, cartilage-like tissues were detected in all groups with positive staining of toluidine blue, Safranin O, and collagen II, indicating the good gelation of dcECM hydrogels. While with the increasing concentration, the tissue engineering cartilages formed by 10 mg/ml dcECM hydrogel grafts were superior in weights, volumes, collagen, and glycosaminoglycan (GAG) content compared to the dcECM hydrogels of 1 mg/ml and 5 mg/ml. At 8 weeks after grafting, dcECM hydrogel grafts at 10 mg/ml showed very similar qualities to the control, collagen I grafts. After 12 weeks of in vivo culture, the histological analysis indicated that 10 mg/ml dcECM hydrogel grafts were similar to the normal cartilage from pig ears, which was the source tissue. In conclusion, dcECM hydrogel showed the promising potential as a tissue engineering biomaterial to improve the regeneration and heal injuries of ear cartilage.

Growth Factors and Scaffold Composition Influence Properties of Tissue Engineered Human Septal Cartilage Implants in a Murine Model

2008 ◽  
Vol 21 (4) ◽  
pp. 807-816 ◽  
Author(s):  
D. Skodacek ◽  
S. Brandau ◽  
T. Deutschle ◽  
S. Lang ◽  
N. Rotter
Keyword(s):  
Tissue Engineering ◽  
Growth Factors ◽  
Ex Vivo ◽  
Septal Cartilage ◽  
Hydroxyproline Content ◽  
Wet Weight ◽  
Cell Carriers ◽  
Scaffold Properties

Several surgical disciplines apply cartilage grafts for reconstructive purposes and have to overcome the scarcity of donor sites for this unique tissue. Employing the techniques of tissue engineering, cartilage might be generated in reasonable amounts for clinical purposes. Application of growth factors together with biochemical and biomechanical scaffold properties influence the process of ex vivo transplant production. The aims of this study are: 1) to investigate the influence of IGF-1 and TGFβ-2 on tissue engineered human septal cartilage in vitro and in vivo after transplantation in nude mice; 2) to analyse the effect of the polydioxanone (PDS) content of the biodegradable Ethisorb E210™ scaffold on the properties of the implanted constructs. Cells were three-dimensionally cultured on biodegradable Ethisorb E210™ (PGA-PLA-copolymer fleeces with polydioxanone (PDS) adhesions), or on E210™ scaffolds with a reduced polydioxanone content. Wet weight (ww), GAG-, and hydroxyprolin-content, as well as the cellularity of the neocartilage constructs were quantitatively evaluated. Additionally, the in vivo resorption of the two types of cell carriers was monitored. Addition of growth factors clearly increased the wet weight of the in vitro cultured constructs before transplantation. After transplantation, high PDS content improved the in vivo stability and macroscopic morphometric appearance of the tissue engineered specimens and led to enhanced deposition of glycosaminoglycans in transplanted constructs. Hydroxyproline content of the implants was not affected by either growth factors or PDS content. These data suggest a role for IGF-1 and TGFß-2 in preparative in vitro culture of chondrocytes before implantation, while PDS content of the scaffold is important for in vivo properties of the implanted material.

scholarly journals Current Advances in the Regeneration of Degenerated Articular Cartilage: A Literature Review on Tissue Engineering and Its Recent Clinical Translation

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 31
Author(s):  
Farah Daou ◽  
Andrea Cochis ◽  
Massimiliano Leigheb ◽  
Lia Rimondini
Keyword(s):  
Tissue Engineering ◽  
Articular Cartilage ◽  
Literature Review ◽  
Healthy Aging ◽  
Ex Vivo ◽  
Cartilage Degeneration ◽  
Clinical Translation ◽  
Predisposing Factor

Functional ability is the basis of healthy aging. Articular cartilage degeneration is amongst the most prevalent degenerative conditions that cause adverse impacts on the quality of life; moreover, it represents a key predisposing factor to osteoarthritis (OA). Both the poor capacity of articular cartilage for self-repair and the unsatisfactory outcomes of available clinical interventions make innovative tissue engineering a promising therapeutic strategy for articular cartilage repair. Significant progress was made in this field; however, a marked heterogeneity in the applied biomaterials, biofabrication, and assessments is nowadays evident by the huge number of research studies published to date. Accordingly, this literature review assimilates the most recent advances in cell-based and cell-free tissue engineering of articular cartilage and also focuses on the assessments performed via various in vitro studies, ex vivo models, preclinical in vivo animal models, and clinical studies in order to provide a broad overview of the latest findings and clinical translation in the context of degenerated articular cartilage and OA.

scholarly journals Corneal Tissue Engineering: An In Vitro Model of the Stromal-nerve Interactions of the Human Cornea

10.3791/56308 ◽  
2018 ◽  
Author(s):  
Rabab Sharif ◽  
Shrestha Priyadarsini ◽  
Tyler G. Rowsey ◽  
Jian-Xing Ma ◽  
Dimitrios Karamichos
Keyword(s):  
Tissue Engineering ◽  
Human Cornea ◽  
Corneal Tissue

scholarly journals Isolation and Propagation of Human Corneal Stromal Keratocytes for Tissue Engineering and Cell Therapy

Cells ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 178
Author(s):  
Nur Zahirah binte M. Yusoff ◽  
Andri K. Riau ◽  
Gary H. F. Yam ◽  
Nuur Shahinda Humaira binte Halim ◽  
Jodhbir S. Mehta
Keyword(s):  
Tissue Engineering ◽  
Cell Therapy ◽  
Structural Integrity ◽  
Corneal Transplantation ◽  
Limiting Factor ◽  
Genotypic Differences ◽  
Corneal Tissue ◽  
Stromal Fibroblasts ◽  
Corneal Opacification

The human corneal stroma contains corneal stromal keratocytes (CSKs) that synthesize and deposit collagens and keratan sulfate proteoglycans into the stromal matrix to maintain the corneal structural integrity and transparency. In adult corneas, CSKs are quiescent and arrested in the G0 phase of the cell cycle. Following injury, some CSKs undergo apoptosis, whereas the surviving cells are activated to become stromal fibroblasts (SFs) and myofibroblasts (MyoFBs), as a natural mechanism of wound healing. The SFs and MyoFBs secrete abnormal extracellular matrix proteins, leading to corneal fibrosis and scar formation (corneal opacification). The issue is compounded by the fact that CSK transformation into SFs or MyoFBs is irreversible in vivo, which leads to chronic opacification. In this scenario, corneal transplantation is the only recourse. The application of cell therapy by replenishing CSKs, propagated in vitro, in the injured corneas has been demonstrated to be efficacious in resolving early-onset corneal opacification. However, expanding CSKs is challenging and has been the limiting factor for the application in corneal tissue engineering and cell therapy. The supplementation of serum in the culture medium promotes cell division but inevitably converts the CSKs into SFs. Similar to the in vivo conditions, the transformation is irreversible, even when the SF culture is switched to a serum-free medium. In the current article, we present a detailed protocol on the isolation and propagation of bona fide human CSKs and the morphological and genotypic differences from SFs.

scholarly journals Experimental Models for Fungal Keratitis: An Overview of Principles and Protocols

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1713
Author(s):  
Micaela L. Montgomery ◽  
Kevin K. Fuller
Keyword(s):  
Ex Vivo ◽  
Treatment Options ◽  
In Vitro Models ◽  
Experimental Models ◽  
Fungal Keratitis ◽  
Corneal Tissue ◽  
Host Determinants ◽  
Fungal Interactions

Fungal keratitis is a potentially blinding infection of the cornea that afflicts diverse patient populations worldwide. The development of better treatment options requires a more thorough understanding of both microbial and host determinants of pathology, and a spectrum of experimental models have been developed toward this end. In vivo (animal) models most accurately capture complex pathological outcomes, but protocols may be challenging to implement and vary widely across research groups. In vitro models allow for the molecular dissection of specific host cell–fungal interactions, but they do so without the appropriate environmental/structural context; ex vivo (corneal explant) models provide the benefits of intact corneal tissue, but they do not provide certain pathological features, such as inflammation. In this review, we endeavor to outline the key features of these experimental models as well as describe key technical variations that could impact study design and outcomes.

CORNEAL TRANSPLANTATION AND THE ARTIFICIAL CORNEA

2003 ◽  
Vol 03 (01) ◽  
pp. 95-106 ◽  
Author(s):  
JULIE ALBON
Keyword(s):  
Corneal Transplantation ◽  
Basic Research ◽  
Corneal Transplant ◽  
Corneal Tissue ◽  
Artificial Cornea ◽  
Surface Protection ◽  
In Vitro Techniques ◽  
Wide Range

The clinical need for an alternative to donor corneal tissue has encouraged much interest in recent years. An artificial cornea whether it be bio-engineered or a synthetic keratoprosthesis must fulfill the functions of the cornea it replaces: transparent, refractive surface, protection, non-immunogenic. A wide range of implants and biomedical devices have been developed in an attempt to correct corneal blindness. Limitation of existing biomaterials are evident when reviewing keratoprosthesis surgery complications. These include infection, intraocular inflammation, retromembrane formation, inadequate interface seal thus epithelial downgrowth and glaucoma. Attempts to improve healing in such cases have involved using various polymers or tissues to surround the optic. The successes and failures of synthetic prostheses that have been implanted in humans is discussed. More recently, the idea of a bio-engineered cornea has arisen. Tissue-engineering involves the manipulation of cells using in vitro techniques to create a composite tissue, which could then be implanted in vivo. Corneal equivalents have been reconstructed from corneal cell lines. They already have their potential uses in the biomedical world: as replacements for animals in toxicology testing and pharmacological studies, as well as in basic research into cell-cell and cell-matrix interactions of corneal wound healing. Current research is ongoing to determine if the bio-engineered cornea will have a role in corneal transplant surgery.

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