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Urbánek P, Šuly P, Ševčík J, Hanulíková B, Kuřitka I, Šopík T, Stodůlka P. Controlled Drug Delivery Device for Cornea Treatment and Novel Method for Its Testing. Pharmaceuticals (Basel) 2023; 16:ph16040505. [PMID: 37111260 PMCID: PMC10143253 DOI: 10.3390/ph16040505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 03/23/2023] [Accepted: 03/24/2023] [Indexed: 03/30/2023] Open
Abstract
A new solution for local anesthetic and antibiotic delivery after eye surgery is presented. A contact lens-shaped collagen drug carrier was created and loaded by Levofloxacin and Tetracaine with a riboflavin crosslinked surface layer, thus impeding diffusion. The crosslinking was confirmed by Raman spectroscopy, whereas the drug release was investigated using UV-Vis spectrometry. Due to the surface barrier, the drug gradually releases into the corneal tissue. To test the function of the carrier, a 3D printed device and a new test method for a controlled drug release, which mimics the geometry and physiological lacrimation rate of the human eye, were developed. The experimental setup with simple geometry revealed that the prepared drug delivery device can provide the prolonged release profile of the pseudo-first-order for up to 72 h. The efficiency of the drug delivery was further demonstrated using a dead porcine cornea as a drug recipient, without the need to use live animals for testing. Our drug delivery system significantly surpasses the efficiency of antibiotic and anesthetic eyedrops that would have to be applied approximately 30 times per hour to achieve the same dose as that delivered continuously by our device.
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Affiliation(s)
- Pavel Urbánek
- Centre of Polymer Systems, Tomas Bata University in Zlín, trida Tomase Bati 5678, 76001 Zlin, Czech Republic
- Correspondence:
| | - Pavol Šuly
- Centre of Polymer Systems, Tomas Bata University in Zlín, trida Tomase Bati 5678, 76001 Zlin, Czech Republic
| | - Jakub Ševčík
- Centre of Polymer Systems, Tomas Bata University in Zlín, trida Tomase Bati 5678, 76001 Zlin, Czech Republic
| | - Barbora Hanulíková
- Centre of Polymer Systems, Tomas Bata University in Zlín, trida Tomase Bati 5678, 76001 Zlin, Czech Republic
| | - Ivo Kuřitka
- Centre of Polymer Systems, Tomas Bata University in Zlín, trida Tomase Bati 5678, 76001 Zlin, Czech Republic
| | - Tomáš Šopík
- Centre of Polymer Systems, Tomas Bata University in Zlín, trida Tomase Bati 5678, 76001 Zlin, Czech Republic
| | - Pavel Stodůlka
- Gemini Eye Clinic, U Gemini 360, 76001 Zlin, Czech Republic
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2
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Integration and remodelling of a collagen anterior lamellar keratoplasty graft in an animal model - A preliminary report. Exp Eye Res 2021; 209:108661. [PMID: 34102207 DOI: 10.1016/j.exer.2021.108661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/24/2021] [Accepted: 06/01/2021] [Indexed: 11/22/2022]
Abstract
There is an international shortage of donor corneas for transplantation to treat the 1.5-2.0 million new cases of blindness secondary to corneal disease. Research has therefore been directed towards the development of artificial corneas using alternative materials such as collagen. The biocompatibility of an acellular collagen-based scaffold for anterior lamellar keratoplasty was investigated in vivo in a rabbit model. This scaffold has previously shown promise as a corneal substitute in vitro. Slit-lamp and Optical Coherence Tomography examinations were carried out at 2 weeks, 1, 2, 3, and 6 months post-operatively. Graft-host integration was investigated using immunohistochemistry of the cornea at 6 months. Results showed that the graft was biocompatible, supported corneal re-epithelialisation, and showed no signs of rejection. Migration of stromal cells into areas of the graft was observed, however this was accompanied by extensive graft digestion. Whilst the scaffold was biocompatible, further modifications to the material or supplementation with matrix metalloproteinase inhibitors are required to bring us closer to a stable and fully integrated corneal substitute.
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Sun X, Yang X, Song W, Ren L. Construction and Evaluation of Collagen-Based Corneal Grafts Using Polycaprolactone To Improve Tension Stress. ACS OMEGA 2020; 5:674-682. [PMID: 31956817 PMCID: PMC6964271 DOI: 10.1021/acsomega.9b03297] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Accepted: 12/18/2019] [Indexed: 05/09/2023]
Abstract
The emergence of innovative surgical procedures using partial thickness corneal transplant has created a need for the development of corneal grafts to replace pathologic corneal tissue. Corneal repair materials have been successfully prepared in the past 10 years, but they were difficult to be used in clinics because of the unbearable tension caused by interrupted suture during routine surgery. However, polycaprolactone (PCL), a medical polymer material, can solve this problem. Therefore, a hierarchical collagen (Col)-based corneal graft with curvature, consisting of a transparent core part composed of collagen in the center and a mechanically robust fixed part containing collagen and polycaprolactone in the edge, was used as a potential corneal graft for corneal repair and regeneration in this study. The hierarchical collagen-based corneal grafts [collagen-polycaprolactone (Col-PCL) membranes] that are capable of mimicking the native cornea were developed based on chemical and thermal crosslinking mechanisms. The water adsorption of Col-PCL membranes could reach over 80% similar to that of human cornea, and its swelling could reach over 400%. More importantly, the formed Col-PCL membranes could resist a larger tensile strength (1.1 ± 0.03 MPa) before rupturing in comparison with pure collagen membranes and polycaprolactone membranes. Furthermore, the biodegradable Col-PCL membranes could facilitate cell adhesion and proliferation as well as cell migration (exhibiting epithelial wound coverage in <5 days), which showed promise as corneal grafts for cornea tissue engineering.
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Affiliation(s)
- Xiaomin Sun
- School
of Materials Science and Engineering, Key Laboratory of Biomedical Engineering
of Guangdong Province, Key Laboratory of Biomedical Materials and Engineering
of the Ministry of Education, and Innovation Center for Tissue Restoration and
Reconstruction, South China University of
Technology, Guangzhou 510006, P. R. China
- National
Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006, P. R. China
| | - Xiangjing Yang
- School
of Materials Science and Engineering, Key Laboratory of Biomedical Engineering
of Guangdong Province, Key Laboratory of Biomedical Materials and Engineering
of the Ministry of Education, and Innovation Center for Tissue Restoration and
Reconstruction, South China University of
Technology, Guangzhou 510006, P. R. China
- National
Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006, P. R. China
| | - Wenjing Song
- School
of Materials Science and Engineering, Key Laboratory of Biomedical Engineering
of Guangdong Province, Key Laboratory of Biomedical Materials and Engineering
of the Ministry of Education, and Innovation Center for Tissue Restoration and
Reconstruction, South China University of
Technology, Guangzhou 510006, P. R. China
- National
Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006, P. R. China
| | - Li Ren
- School
of Materials Science and Engineering, Key Laboratory of Biomedical Engineering
of Guangdong Province, Key Laboratory of Biomedical Materials and Engineering
of the Ministry of Education, and Innovation Center for Tissue Restoration and
Reconstruction, South China University of
Technology, Guangzhou 510006, P. R. China
- National
Engineering Research Center for Tissue Restoration and Reconstruction, Guangzhou 510006, P. R. China
- Sino-Singapore
International Joint Research Institute, Guangzhou 510555, P. R. China
- Guangzhou
Regenerative Medicine and Health Guangdong Laboratory, Guangzhou 510005, P. R. China
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Lagali N, Rafat M. Femtosecond Laser-Assisted Surgery for Implantation of Bioengineered Corneal Stroma to Promote Corneal Regeneration. Methods Mol Biol 2020; 2145:197-214. [PMID: 32542609 DOI: 10.1007/978-1-0716-0599-8_14] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The femtosecond laser has achieved widespread use in ophthalmology owing to its ability to deliver focused high energy that is rapidly dissipated and thereby does not damage surrounding tissue outside the precise focal region. Extremely accurate and smooth cuts can be made by the laser, enabling a range of applications in anterior segment surgery. Minimally invasive corneal surgical procedures can be performed using the femtosecond laser, and here we describe the application of such procedures to improve implantation of bioengineered materials into the cornea. Bioengineered corneal tissue, including the collagenous corneal stroma, promises to provide a virtually unlimited supply of biocompatible tissue for treating multiple causes of corneal blindness globally, thereby circumventing problems of donor tissue shortages and access to tissue banking infrastructure. Optimal implantation of bioengineered materials, however, is required, in order to facilitate postoperative wound healing for the maintenance of corneal transparency and avoidance of postoperative complications such as scarring, inflammation, and neovascularization. Moreover, the avoidance of a detrimental physiological physiological wound healing response is critical for facilitating the corneal stromal regeneration enabled by the bioengineered stroma. Without proper implantation, the tissue response will favor inflammation and pathologic processes instead of quiescent keratocyte migration and new collagen production. Here we describe several procedures for optimized biomaterial implantation into the corneal stroma, that facilitate rapid wound healing and regenerative restoration of corneal transparency without the use of human donor tissue. A step-by-step methodology is provided for the use of the femtosecond laser and associated techniques, to enable seamless integration of bioengineered materials into the corneal stroma.
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Affiliation(s)
- Neil Lagali
- Division of Ophthalmology, Institute for Biomedical and Clinical Sciences, Linköping University, Linköping, Sweden.
| | - Mehrdad Rafat
- Department of Biomedical Engineering, Linköping University, Linköping, Sweden.,LinkoCare Life Sciences AB, Linköping, Sweden
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Rose JB, Sidney LE, Patient J, White LJ, Dua HS, El Haj AJ, Hopkinson A, Rose FR. In vitro
evaluation of electrospun blends of gelatin and PCL for application as a partial thickness corneal graft. J Biomed Mater Res A 2019; 107:828-838. [DOI: 10.1002/jbm.a.36598] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 11/14/2018] [Accepted: 12/05/2018] [Indexed: 12/13/2022]
Affiliation(s)
- James B. Rose
- Centre for Biomolecular Sciences, School of Pharmacy; University of Nottingham; NG7 2RD United Kingdom
| | - Laura E. Sidney
- Academic Ophthalmology, Division of Clinical Neuroscience; University of Nottingham; Queen's Medical Centre Campus, NG7 2UH United Kingdom
| | - James Patient
- Centre for Biomolecular Sciences, School of Pharmacy; University of Nottingham; NG7 2RD United Kingdom
| | - Lisa J. White
- Centre for Biomolecular Sciences, School of Pharmacy; University of Nottingham; NG7 2RD United Kingdom
| | - Harminder S. Dua
- Academic Ophthalmology, Division of Clinical Neuroscience; University of Nottingham; Queen's Medical Centre Campus, NG7 2UH United Kingdom
| | - Alicia J. El Haj
- Institute for Science and Technology in Medicine, School of Medicine; Keele University; Stoke-on-Trent, ST4 7QB United Kingdom
| | - Andrew Hopkinson
- Academic Ophthalmology, Division of Clinical Neuroscience; University of Nottingham; Queen's Medical Centre Campus, NG7 2UH United Kingdom
| | - Felicity R.A.J. Rose
- Centre for Biomolecular Sciences, School of Pharmacy; University of Nottingham; NG7 2RD United Kingdom
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Yu T, Rajendran V, Griffith M, Forrester JV, Kuffová L. High-risk corneal allografts: A therapeutic challenge. World J Transplant 2016; 6:10-27. [PMID: 27011902 PMCID: PMC4801785 DOI: 10.5500/wjt.v6.i1.10] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Revised: 10/03/2015] [Accepted: 12/04/2015] [Indexed: 02/05/2023] Open
Abstract
Corneal transplantation is the most common surgical procedure amongst solid organ transplants with a high survival rate of 86% at 1-year post-grafting. This high success rate has been attributed to the immune privilege of the eye. However, mechanisms originally thought to promote immune privilege, such as the lack of antigen presenting cells and vessels in the cornea, are challenged by recent studies. Nevertheless, the immunological and physiological features of the cornea promoting a relatively weak alloimmune response is likely responsible for the high survival rate in “low-risk” settings. Furthermore, although corneal graft survival in “low-risk” recipients is favourable, the prognosis in “high-risk” recipients for corneal graft is poor. In “high-risk” grafts, the process of indirect allorecognition is accelerated by the enhanced innate and adaptive immune responses due to pre-existing inflammation and neovascularization of the host bed. This leads to the irreversible rejection of the allograft and ultimately graft failure. Many therapeutic measures are being tested in pre-clinical and clinical studies to counter the immunological challenge of “high-risk” recipients. Despite the prevailing dogma, recent data suggest that tissue matching together with use of systemic immunosuppression may increase the likelihood of graft acceptance in “high-risk” recipients. However, immunosuppressive drugs are accompanied with intolerance/side effects and toxicity, and therefore, novel cell-based therapies are in development which target host immune cells and restore immune homeostasis without significant side effect of treatment. In addition, developments in regenerative medicine may be able to solve both important short comings of allotransplantation: (1) graft rejection and ultimate graft failure; and (2) the lack of suitable donor corneas. The advances in technology and research indicate that wider therapeutic choices for patients may be available to address the worldwide problem of corneal blindness in both “low-risk” and “high-risk” hosts.
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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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Koulikovska M, Rafat M, Petrovski G, Veréb Z, Akhtar S, Fagerholm P, Lagali N. Enhanced regeneration of corneal tissue via a bioengineered collagen construct implanted by a nondisruptive surgical technique. Tissue Eng Part A 2015; 21:1116-30. [PMID: 25412075 DOI: 10.1089/ten.tea.2014.0562] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Severe shortage of donor corneas for transplantation, particularly in developing countries, has prompted the advancement of bioengineered tissue alternatives. Bioengineered corneas that can withstand transplantation while maintaining transparency and compatibility with host cells, and that are additionally amenable to standardized low-cost mass production are sought. In this study, a bioengineered porcine construct (BPC) was developed to function as a biodegradable scaffold to promote corneal stromal regeneration by host cells. Using high-purity medical-grade type I collagen, high 18% collagen content and optimized EDC-NHS cross-linker ratio, BPCs were fabricated into hydrogel corneal implants with over 90% transparency and four-fold increase in strength and stiffness compared with previous versions. Remarkably, optical transparency was achieved despite the absence of collagen fibril organization at the nanoscale. In vitro testing indicated that BPC supported confluent human epithelial and stromal-derived mesenchymal stem cell populations. With a novel femtosecond laser-assisted corneal surgical model in rabbits, cell-free BPCs were implanted in vivo in the corneal stroma of 10 rabbits over an 8-week period. In vivo, transparency of implanted corneas was maintained throughout the postoperative period, while healing occurred rapidly without inflammation and without the use of postoperative steroids. BPC implants had a 100% retention rate at 8 weeks, when host stromal cells began to migrate into implants. Direct histochemical evidence of stromal tissue regeneration was observed by means of migrated host cells producing new collagen from within the implants. This study indicates that a cost-effective BPC extracellular matrix equivalent can incorporate cells passively to initiate regenerative healing of the corneal stroma, and is compatible with human stem or organ-specific cells for future therapeutic applications as a stromal replacement for treating blinding disorders of the cornea.
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Rose JB, Pacelli S, Haj AJE, Dua HS, Hopkinson A, White LJ, Rose FRAJ. Gelatin-Based Materials in Ocular Tissue Engineering. MATERIALS (BASEL, SWITZERLAND) 2014; 7:3106-3135. [PMID: 28788609 PMCID: PMC5453355 DOI: 10.3390/ma7043106] [Citation(s) in RCA: 198] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Revised: 03/17/2014] [Accepted: 03/24/2014] [Indexed: 12/13/2022]
Abstract
Gelatin has been used for many years in pharmaceutical formulation, cell culture and tissue engineering on account of its excellent biocompatibility, ease of processing and availability at low cost. Over the last decade gelatin has been extensively evaluated for numerous ocular applications serving as cell-sheet carriers, bio-adhesives and bio-artificial grafts. These different applications naturally have diverse physical, chemical and biological requirements and this has prompted research into the modification of gelatin and its derivatives. The crosslinking of gelatin alone or in combination with natural or synthetic biopolymers has produced a variety of scaffolds that could be suitable for ocular applications. This review focuses on methods to crosslink gelatin-based materials and how the resulting materials have been applied in ocular tissue engineering. Critical discussion of recent innovations in tissue engineering and regenerative medicine will highlight future opportunities for gelatin-based materials in ophthalmology.
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Affiliation(s)
- James B Rose
- School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Settimio Pacelli
- Department of Drug Chemistry and Technologies, "Sapienza" University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy.
| | - Alicia J El Haj
- Institute for Science and Technology in Medicine, Keele University, Stoke-on-Trent ST4 7QB, UK.
| | - Harminder S Dua
- Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Andrew Hopkinson
- Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham NG7 2RD, UK.
| | - Lisa J White
- School of Pharmacy, University of Nottingham, Nottingham NG7 2RD, UK.
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Lamm V, Hara H, Mammen A, Dhaliwal D, Cooper DK. Corneal blindness and xenotransplantation. Xenotransplantation 2014; 21:99-114. [PMID: 25268248 PMCID: PMC4181387 DOI: 10.1111/xen.12082] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 12/07/2013] [Indexed: 12/13/2022]
Abstract
Approximately 39 million people are blind worldwide, with an estimated 285 million visually impaired. The developing world shoulders 90% of the world's blindness, with 80% of causative diseases being preventable or treatable. Blindness has a major detrimental impact on the patient, community, and healthcare spending. Corneal diseases are significant causes of blindness, affecting at least 4 million people worldwide. The prevalence of corneal disease varies between parts of the world. Trachoma, for instance, is the second leading cause of blindness in Africa, after cataracts, but is rarely found today in developed nations. When preventive strategies have failed, corneal transplantation is the most effective treatment for advanced corneal disease. The major surgical techniques for corneal transplantation include penetrating keratoplasty (PK), anterior lamellar keratoplasty, and endothelial keratoplasty (EK). Indications for corneal transplantation vary between countries, with Fuchs' dystrophy being the leading indication in the USA and keratoconus in Australia. With the exception of the USA, where EK will soon overtake PK as the most common surgical procedure, PK is the overwhelming procedure of choice. Success using corneal grafts in developing nations, such as Nepal, demonstrates the feasibility of corneal transplantation on a global scale. The number of suitable corneas from deceased human donors that becomes available will never be sufficient, and so research into various alternatives, for example stem cells, amniotic membrane transplantation, synthetic and biosynthetic corneas, and xenotransplantation, is progressing. While each of these has potential, we suggest that xenotransplantation holds the greatest potential for a corneal replacement. With the increasing availability of genetically engineered pigs, pig corneas may alleviate the global shortage of corneas in the near future.
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Affiliation(s)
- Vladimir Lamm
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Hidetaka Hara
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Alex Mammen
- Eye and Ear Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Deepinder Dhaliwal
- Eye and Ear Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - David K.C. Cooper
- Thomas E. Starzl Transplantation Institute, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
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Bath C. Human corneal epithelial subpopulations: oxygen dependent ex vivo expansion and transcriptional profiling. Acta Ophthalmol 2013; 91 Thesis 4:1-34. [PMID: 23732018 DOI: 10.1111/aos.12157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Corneal epithelium is being regenerated throughout life by limbal epithelial stem cells (LESCs) believed to be located in histologically defined stem cell niches in corneal limbus. Defective or dysfunctional LESCs result in limbal stem cell deficiency (LSCD) causing pain and decreased visual acuity. Since the first successful treatment of LSCD by transplantation of ex vivo expanded LESCs in 1997, many attempts have been carried out to optimize culture conditions to improve the outcome of surgery. To date, progress in this field of bioengineering is substantially hindered by both the lack of specific biomarkers of LESCs and the lack of a precise molecular characterization of in situ epithelial subpopulations. The aim of this dissertation was to optimize culture systems with regard to the environmental oxygen concentration for selective ex vivo expansion of LESCs and to analyse in situ subpopulations in human corneal epithelium using a combination of laser capture microdissection and RNA sequencing for global transcriptomic profiling. We compared dissociation cultures, using either expansion on γ-irradiated NIH/3T3 feeder cells in serum-rich medium or expansion directly on plastic in serum-free EpiLife medium, using a range of physiologically relevant oxygen concentrations (2%, 5%, 10%, 15% and 20%). Using immunocytochemistry and advanced fluorescence microscopy, cells were characterized regarding growth, cell cycle distribution, colony-forming efficiency (CFE), phenotypes and cytomorphometry. Limbal epithelial cells expanded in 2% O2 exhibited slow growth, low fraction of cells in S/G2 , high CFE, high expression of stem cell markers ABCG2 and p63α, and low fraction of differentiation marker CK3 resembling a LESC phenotype. The effect of hypoxia to maintain LESCs in culture was not dependent on the system used for propagation (Bath et al. 2013a). Laser capture microdissection was used to isolate cellular subpopulations in situ from the spatially defined differentiation pathway in human corneal epithelium according to an optimized protocol for maintenance of expression profiles. Isolated total RNA from basal limbal crypts (BLCs), superficial limbal crypts (SLCs), paracentral/central cornea and limbal stroma was amplified and converted to fragmented cDNA libraries for use in deep paired-end next-generation sequencing. Global transcriptional profiling was carried out using bioinformatics. The location of primitive cells in BLCs, migratory and activated cells in SLCs and differentiated cells in paracentral/central cornea was evident from mapping of significantly upregulated genes in each compartment to the gene ontology (GO). Interestingly, many GO terms in BLCs were also involved in neurogenic processes, whereas many GO terms in SLCs were related to vasculature. Mapping upregulated genes in BLCs to pathway annotations in Kyoto Encyclopedia of Genes and Genomes described many active pathways as signalling and cancer-associated pathways. We supply extensive information on possible novel biomarkers, reveal insight into both active pathways and novel regulators of LESCs such as Lrig1 and SOX9 and provide an immense amount of data for future exploration (Bath et al. 2013b). Selective ex vivo expansion of LESCs in hypoxia and the comprehensive molecular characterization of corneal epithelial subpopulations in situ are expected to be beneficial for the future treatment of LSCD by cultured limbal epithelial transplantation.
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Affiliation(s)
- Chris Bath
- Department of Ophthalmology, Aalborg University Hospital, Aalborg, Denmark
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Abstract
Almost 300 million people are visually impaired worldwide due to various eye diseases such as cataracts, glaucoma, age-related macular degeneration, diabetic retinopathy, and corneal diseases. Notably, ten million people are blind because of severe ocular surface diseases and the majority of cases occur in developing countries. Blinding ocular surface diseases have, however, become treatable by grafting of surface layers, or by full-thickness transplantation of the cornea. As the demand for human corneal tissue for surface reconstruction and transplantation far exceeds the supply, methods are being developed to supplement tissue donation. Xenotransplantation of the cornea or cells from genetically modified pigs may become one of the solutions. Transplantation of limbal stem cells within tissue biopsies, to restore the transparency of the cornea is another remarkable method, which has shown its potential in several clinical studies. The combination of stem cell technology and engineering of biocompatible tissue equivalent, still at preclinical stage, has shown us how synthetic corneal tissue is able to guide cultured corneal stromal stem cells of human origin, to become native-like stroma, the most important layer of the cornea. These findings give hope for a large-quantity production of biomaterial for corneal reconstruction. As such, clinical ophthalmologists should become more familiar with the methods of laboratory science.
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Affiliation(s)
- Olli Arjamaa
- Department of Biology, University of Turku, Turku, Finland
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Liu Y, Yang J, Zhang P, Liu C, Wang W, Liu W. ZnO quantum dots-embedded collagen/polyanion composite hydrogels with integrated functions of degradation tracking/inhibition and gene delivery. ACTA ACUST UNITED AC 2012. [DOI: 10.1039/c1jm13063c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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