scholarly journals Effect of Cross-Linking Density on the Structures and Properties of Carbodiimide-Treated Gelatin Matrices as Limbal Stem Cell Niches

2018 ◽  
Vol 19 (11) ◽  
pp. 3294 ◽  
Author(s):  
Jui-Yang Lai ◽  
Li-Jyuan Luo ◽  
David Ma
Keyword(s):  
Surface Roughness ◽  
Stem Cell ◽  
Cross Linking ◽  
Epithelial Tissue ◽  
Human Amniotic Membrane ◽  
Limbal Stem Cells ◽  
Structures And Properties ◽  
Cross Linker ◽  
Limbal Stem Cell ◽  
Stem Cell Niches

Given that human amniotic membrane is a valuable biological material not readily available for corneal epithelial tissue engineering, gelatin is considered as a potential alternative to construct a cellular microenvironment. This study investigates, for the first time, the influence of cross-linking density of carbodiimide-treated gelatin matrices on the structures and properties of artificial limbal stem cell niches. Our results showed that an increase in the carbodiimide concentration from 1.5 to 15 mM leads to an upward trend in the structural and suture strength of biopolymers. Furthermore, increasing number of cross-linking bridges capable of linking protein molecules together may reduce their crystallinity. For the samples treated with 50 mM of cross-linker (i.e., the presence of excess N-substituted carbodiimide), abundant N-acylurea was detected, which was detrimental to the in vitro and in vivo ocular biocompatibility of gelatin matrices. Surface roughness and stiffness of biopolymer substrates were found to be positively correlated with carbodiimide-induced cross-link formation. Significant increases of integrin β1 expression, metabolic activity, and ABCG2 expression were noted as the cross-linker concentration increased, suggesting that the bulk crystalline structure and surface roughness/stiffness of niche attributed to the number of cross-linking bridges may have profound effects on a variety of limbal epithelial cell behaviors, including adhesion, proliferation, and stemness maintenance. In summary, taking the advantages of carbodiimide cross-linking-mediated development of gelatin matrices, new niches with tunable cross-linking densities can provide a significant boost to maintain the limbal stem cells during ex vivo expansion.

Interrelationship between cross-linking structure, molecular stability, and cytocompatibility of amniotic membranes cross-linked with glutaraldehyde of varying concentrations

RSC Advances ◽  
2014 ◽  
Vol 4 (36) ◽  
pp. 18871-18880 ◽  
Author(s):  
Jui-Yang Lai
Keyword(s):  
Stem Cell ◽  
Stem Cell Niche ◽  
Cross Linking ◽  
Marked Influence ◽  
Molecular Stability ◽  
Cross Linker ◽  
Limbal Stem Cell ◽  
Cell Niche ◽  
Amniotic Membranes ◽  
Limbal Stem Cell Niche

Chemical cross-linker concentration has a marked influence on the interrelationship between cross-linking structure, molecular stability, and cytocompatibility of a glutaraldehyde-treated amniotic membrane for a limbal stem cell niche.

scholarly journals Evaluation of an Improved Chitosan Scaffold Cross-Linked With Polyvinyl Alcohol and Amine Coupling Through 1-Ethyl-3-(3-Dimethyl Aminopropyl)-Carbodiimide (EDC) and 2 N-Hydroxysuccinimide (NHS) for Corneal Applications

2018 ◽  
Vol 6 (9) ◽  
pp. 1561-1570 ◽  
Author(s):  
Mohamed Ali Seyed ◽  
Kavitha Vijayaraghavan
Keyword(s):  
Cross Linking ◽  
In Vitro Tests ◽  
Human Amniotic Membrane ◽  
Limbal Stem Cells ◽  
Chitosan Scaffold ◽  
Polymeric Chains ◽  
Ft Ir ◽  
Colloidal State ◽  
Corneal Blindness

BACKGROUND: Corneal blindness resulting from various medical conditions affects millions worldwide. The rapid developing tissue engineering field offers design of a scaffold with mechanical properties and transparency similar to that of the natural cornea. AIM: The present study aimed at to prepare and investigate the properties of PVA/chitosan blended scaffold by further cross-linking with 1-Ethyl-3-(3-dimethyl aminopropyl)-carbodiimide (EDC) and 2 N-Hydroxysuccinimide (NHS) as potential in vitro carrier for human limbal stem cells delivery. MATERIAL AND METHODS: Acetic acid dissolved chitosan was added to PVA solution, uniformly mixed with a homogenizer until the mixture was in a colloidal state, followed by H2SO4 and formaldehyde added and the sample was allowed to cool, subsequently it was poured into a tube and heated in an oven at 60°C for 50 minutes. Finally, samples were soaked in a cross-linking bath with EDC, NHS and NaOH in H2O/EtOH for 24 h consecutively stirred to cross-link the polymeric chains, reduce degradation. After soaking in the bath, the samples were carefully washed with 2% glycine aqueous solution several times to remove the remaining amount of cross-linkers, followed by washed with water to remove residual agents. Later the cross-linked scaffold subjected for various characterization and biological experiments. RESULTS: After viscosity measurement, the scaffold was observed by Fourier transform infrared (FT-IR). The water absorbency of PVA/Chitosan was increased 361% by swelling. Compression testing demonstrated that by increasing the amount of chitosan, the strength of the scaffold could be increased to 16×10−1 MPa. Our degradation results revealed by mass loss using equation shows that scaffold degraded gradually imply slow degradation. In vitro tests showed good cell proliferation and growth in the scaffold. Our assay results confirmed that the membrane could increase the cells adhesion and growth on the substrate. CONCLUSION: Hence, we strongly believe the use of this improved PVA/chitosan scaffold has potential to cut down the disadvantages of the human amniotic membrane (HAM) for corneal epithelium in ocular surface surgery and greater mechanical strength in future after successful experimentation with clinical trials.

scholarly journals Limbal Stem Cell-Sparing Corneoscleroplasty with Peripheral Intralamellar Tuck: A New Surgical Technique for Keratoglobus

2017 ◽  
Vol 8 (1) ◽  
pp. 279-287
Author(s):  
Elias Jarade ◽  
Rafic Antonios ◽  
Sylvain el-Khoury
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Structural Integrity ◽  
Single Step ◽  
Limbal Stem Cells ◽  
Host Cornea ◽  
Limbal Stem Cell ◽  
The Right ◽  
New Surgical Technique

Purpose: To describe the technique of limbal stem cell-sparing corneoscleroplasty for the management of advanced keratoglobus. Methods: A patient with bilateral advanced keratoglobus, with best-corrected visual acuity of 20/400 in the right eye and 20/200 in the left eye, underwent limbal stem cell-sparing corneoscleroplasty of the right eye. Initially, a 360-degree limbal incision with 200-μm depth was created, followed by a sublimbal tunnel dissection into the sclera, in order to conserve stem cells. Next, a limbus-to-limbus lamellar keratectomy at 200-μm depth was performed. Meanwhile, a donor corneoscleral button with preserved endothelium of the central 8 mm was fashioned. Prior to suturing the donor corneoscleral graft using a modified suturing technique to cover its scleral component, a full-thickness trephination of 8-mm diameter was completed in the central host cornea. Results: Reepithelialization occurred within the first week. No episodes of rejection, intraocular pressure spikes, or epithelial breakdown were observed postoperatively. At the 6-month follow-up, the patient had 20/70 best-corrected vision and a smooth cornea with regular astigmatism on topography. Conclusion: Limbal stem cell-sparing corneoscleroplasty is a single-step technique for restoring the structural integrity of the cornea in advanced keratoglobus while preserving the host limbal stem cells.

scholarly journals Limbal stem cell deficiency: etiology, pathogenesis, priniciples and prospects of surgical treatment

2019 ◽  
Vol 12 (1) ◽  
pp. 103-111
Author(s):  
A. S. Dubovikov ◽  
I. O. Gavrilyuk ◽  
A. N. Kulikov ◽  
S. V. Churashov ◽  
V. F. Chernysh ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Surgical Treatment ◽  
Ex Vivo ◽  
Epithelial Stem Cells ◽  
Limbal Stem Cells ◽  
History Of Development ◽  
History Of ◽  
Limbal Epithelial Stem Cells ◽  
Limbal Stem Cell

The review is focused on the modern view of the etiology and pathogenesis of limbal stem cells deficiency. The history of development of tissue and ex-vivo transplantation of limbal epithelial stem cells is presented. Certain promising directions of the treatment of patients with limbal stem cells deficiency are presented.

scholarly journals Cultivated Limbal Stem Cell Transplantation—The Surgical Technique

2012 ◽  
Vol 05 (01) ◽  
pp. 22
Author(s):  
Virender S Sangwan ◽  
Keyword(s):  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Surgical Techniques ◽  
Light Sensitivity ◽  
Human Amniotic Membrane ◽  
Ocular Injury ◽  
Immune Mediated ◽  
Limbal Stem Cell Transplantation ◽  
Limbal Stem Cell

Limbal stem cell deficiency (LSCD) is characterized by loss of limbal palisades of Vogt, ingrowth of conjunctiva on to the cornea, and recurrent or persistent epithelial defects of the cornea. This results in pain, watering, decrease in vision, and light sensitivity. LSCD is most commonly caused by ocular injury, immune-mediated ocular surface diseases, and aniridia. A variety of surgical techniques have been described to treat LSCD, but cultivated limbal stem cell transplantation seems the most promising. In this technique a small biopsy is harvested from healthy limbus, either of the same eye or the other eye. The limbal tissue is shredded into small pieces and seeded on to de-epithelialized human amniotic membrane. The human corneal epithelial medium is used to grow the cells. Twelve to 14 days of culture gives enough cells for clinical transplantation.

scholarly journals Hyaluronan-Based Hydrogel Scaffolds for Limbal Stem Cell Transplantation: A Review

Cells ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 245 ◽  
Author(s):  
Mazyar Yazdani ◽  
Aboulghassem Shahdadfar ◽  
Catherine Joan Jackson ◽  
Tor Paaske Utheim
Keyword(s):  
Extracellular Matrix ◽  
Stem Cell ◽  
Limbal Stem Cells ◽  
Receptor Proteins ◽  
Hydrogel Scaffolds ◽  
Cell Based Therapy ◽  
Limbal Stem Cell Transplantation ◽  
Limbal Stem Cell ◽  
Cell Niche ◽  
Synthesis And Degradation

Hyaluronan (HA), also termed hyaluronic acid or hyaluronate, is a major component of the extracellular matrix. This non-sulfated glycosaminoglycan plays a key role in cell proliferation, growth, survival, polarization, and differentiation. The diverse biological roles of HA are linked to the combination of HA’s physicochemical properties and HA-binding proteins. These unique characteristics have encouraged the application of HA-based hydrogel scaffolds for stem cell-based therapy, a successful method in the treatment of limbal stem cell deficiency (LSCD). This condition occurs following direct damage to limbal stem cells and/or changes in the limbal stem cell niche microenvironment due to intrinsic and extrinsic insults. This paper reviews the physical properties, synthesis, and degradation of HA. In addition, the interaction of HA with other extracellular matrix (ECM) components and receptor proteins are discussed. Finally, studies employing HA-based hydrogel scaffolds in the treatment of LSCD are reviewed.

AUTOLOGOUS FIBRIN-CULTURED LIMBAL STEM CELLS PERMANENTLY RESTORE THE CORNEAL SURFACE OF PATIENTS WITH TOTAL LIMBAL STEM CELL DEFICIENCY1

2001 ◽  
Vol 72 (9) ◽  
pp. 1478-1485 ◽  
Author(s):  
Paolo Rama ◽  
Stefano Bonini ◽  
Alessandro Lambiase ◽  
Osvaldo Golisano ◽  
Patrizia Paterna ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Limbal Stem Cells ◽  
Corneal Surface ◽  
Limbal Stem Cell

scholarly journals Clinical Trials of Limbal Stem Cell Deficiency Treated with Oral Mucosal Epithelial Cells

2020 ◽  
Vol 21 (2) ◽  
pp. 411 ◽  
Author(s):  
Joan Oliva ◽  
Fawzia Bardag-Gorce ◽  
Yutaka Niihara
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Corneal Epithelium ◽  
Contact Lenses ◽  
Embryonic Stem ◽  
Epithelial Stem Cells ◽  
Physical Damage ◽  
Limbal Stem Cells ◽  
Cell Therapies ◽  
Limbal Stem Cell

The corneal surface is an essential organ necessary for vision, and its clarity must be maintained. The corneal epithelium is renewed by limbal stem cells, located in the limbus and in palisades of Vogt. Palisades of Vogt maintain the clearness of the corneal epithelium by blocking the growth of conjunctival epithelium and the invasion of blood vessels over the cornea. The limbal region can be damaged by chemical burns, physical damage (e.g., by contact lenses), congenital disease, chronic inflammation, or limbal surgeries. The degree of limbus damage is associated with the degree of limbal stem cells deficiency (partial or total). For a long time, the only treatment to restore vision was grafting part of the healthy cornea from the other eye of the patient or by transplanting a cornea from cadavers. The regenerative medicine and stem cell therapies have been applied to restore normal vision using different methodologies. The source of stem cells varies from embryonic stem cells, mesenchymal stem cells, to induced pluripotent stem cells. This review focuses on the use of oral mucosa epithelial stem cells and their use in engineering cell sheets to treat limbal stem cell deficient patients.

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