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Li Z, Böhringer D, Stachon T, Nastaranpour M, Fries FN, Seitz B, Ulrich M, Munteanu C, Langenbucher A, Szentmáry N. Culturing Limbal Epithelial Cells of Long-term Stored Corneal Donors (Organ Culture) In Vitro - A Stepwise Linear Regression Algorithm. Klin Monbl Augenheilkd 2023. [PMID: 37130569 DOI: 10.1055/a-2084-7168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
PURPOSE To assess various potential factors on human limbal epithelial cell (LEC) outgrowth in vitro using corneal donor tissue following long-term storage (organ culture) and a stepwise linear regression algorithm. METHODS Of 215 donors, 304 corneoscleral rings were used for our experiments. For digestion of the limbal tissue and isolation of the limbal epithelial cells, the tissue pieces were incubated with 4.0 mg/mL collagenase A at 37 °C with 95% relative humidity and a 5% CO2 atmosphere overnight. Thereafter, limbal epithelial cells were separated from limbal keratocytes using a 20-µm CellTricks filter. The separated human LECs were cultured in keratinocyte serum-free medium medium, 1% penicillin/streptomycin (P/S), 0.02% epidermal growth factor (EGF), and 0.3% bovine pituitary extract (BPE). The potential effect of donor age (covariate), postmortem time (covariate), medium time (covariate), size of the used corneoscleral ring (360°, 270°180°, 120°, 90°, less than 90°) (covariate), endothelial cell density (ECD) (covariate), gender (factor), number of culture medium changes during organ culture (factor), and origin of the donor (donating institution and storing institution, factor) on the limbal epithelial cell outgrowth was analyzed with a stepwise linear regression algorithm. RESULTS The rate of successful human LEC outgrowth was 37.5%. From the stepwise linear regression algorithm, we found out that the relevant influencing parameters on the LEC growth were intercept (p < 0.001), donor age (p = 0.002), number of culture medium changes during organ culture (p < 0.001), total medium time (p = 0.181), and size of the used corneoscleral ring (p = 0.007), as well as medium time × size of the corneoscleral ring (p = 0.007). CONCLUSIONS The success of LEC outgrowth increases with lower donor age, lower number of organ culture medium changes during storage, shorter medium time in organ culture, and smaller corneoscleral ring size. Our stepwise linear regression algorithm may help us in optimizing LEC cultures in vitro.
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Affiliation(s)
- Zhen Li
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Congenital Aniridia Research, Saarland University, Homburg, Germany
| | - Daniel Böhringer
- Department of Ophthalmology, University of Freiburg, Freiburg im Breisgau, Germany
| | - Tanja Stachon
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Congenital Aniridia Research, Saarland University, Homburg, Germany
| | - Mahsa Nastaranpour
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Congenital Aniridia Research, Saarland University, Homburg, Germany
| | - Fabian Norbert Fries
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Congenital Aniridia Research, Saarland University, Homburg, Germany
- Department of Ophthalmology, Saarland University, Homburg, Germany
| | - Berthold Seitz
- Department of Ophthalmology, Saarland University, Homburg, Germany
| | - Myriam Ulrich
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Congenital Aniridia Research, Saarland University, Homburg, Germany
| | | | | | - Nóra Szentmáry
- Dr. Rolf M. Schwiete Center for Limbal Stem Cell and Congenital Aniridia Research, Saarland University, Homburg, Germany
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2
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Tavakkoli F, Eleiwa TK, Elhusseiny AM, Damala M, Rai AK, Cheraqpour K, Ansari MH, Doroudian M, H Keshel S, Soleimani M, Djalilian AR, Sangwan VS, Singh V. Corneal stem cells niche and homeostasis impacts in regenerative medicine; concise review. Eur J Ophthalmol 2023:11206721221150065. [PMID: 36604831 DOI: 10.1177/11206721221150065] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The limbal stem cells niche (LSCN) is an optimal microenvironment that provides the limbal epithelial stem cells (LESCs) and strictly regulates their proliferation and differentiation. Disturbing the LSCN homeostasis can lead to limbal stem cell dysfunction (LSCD) and subsequent ocular surface aberrations, such as corneal stromal inflammation, persistent epithelial defects, corneal neovascularisation, lymphangiogenesis, corneal opacification, and conjunctivalization. As ocular surface disorders are considered the second main cause of blindness, it becomes crucial to explore different therapeutic strategies for restoring the functions of the LSCN. A major limitation of corneal transplantation is the current shortage of donor tissue to meet the requirements worldwide. In this context, it becomes mandatory to find an alternative regenerative medicine, such as using cultured limbal epithelial/stromal stem cells, inducing the production of corneal like cells by using other sources of stem cells, and using tissue engineering methods aiming to produce the three-dimensional (3D) printed cornea. Limbal epithelial stem cells have been considered the magic potion for eye treatment. Epithelial and stromal stem cells in the limbal niche hold the responsibility of replenishing the corneal epithelium. These stem cells are being used for transplantation to maintain corneal epithelial integrity and ultimately sustain optimal vision. In this review, we summarised the characteristics of the LSCN and their current and future roles in restoring corneal homeostasis in eyes with LSCD.
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Affiliation(s)
- Fatemeh Tavakkoli
- Department of Community Health, College of Health Technology, Cihan University, Erbil, Iraq.,SSR Stem Cell Biology Laboratory, Brien Holden Eye Research Centre, Centre for Ocular Regeneration, Hyderabad Eye Research Foundation, L.V. Prasad Eye Institute, Hyderabad, India.,Centre for Genetic Disorders, Banaras Hindu University, Varanasi, India
| | - Taher K Eleiwa
- Department of Ophthalmology, Benha University, Benha, Egypt
| | - Abdelrahman M Elhusseiny
- Department of Ophthalmology, Harvey and Bernice Jones Eye Institute, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Mukesh Damala
- SSR Stem Cell Biology Laboratory, Brien Holden Eye Research Centre, Centre for Ocular Regeneration, Hyderabad Eye Research Foundation, L.V. Prasad Eye Institute, Hyderabad, India.,School of Life Sciences, University of Hyderabad, Hyderabad, India
| | - Amit K Rai
- Centre for Genetic Disorders, Banaras Hindu University, Varanasi, India
| | - Kasra Cheraqpour
- Translational Eye Research Center, Farabi Eye Hospital, 48439Tehran University of Medical Sciences, Tehran, Iran
| | - Mohammad H Ansari
- Ophthalmic Research Center, Department of Ophthalmology, Labbafinejad Medical Center, 556492Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Doroudian
- Department of Cell and Molecular Biology, Faculty of Biological Sciences, 145440Kharazmi University, Tehran, Iran
| | - Saeed H Keshel
- Department of Tissue Engineering and Applied Cell Sciences, 556492Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Mohammad Soleimani
- Department of Ophthalmology, 159636Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
| | - Ali R Djalilian
- Department of Ophthalmology, 159636Illinois Eye and Ear Infirmary, University of Illinois at Chicago, Chicago, IL, USA
| | | | - Vivek Singh
- SSR Stem Cell Biology Laboratory, Brien Holden Eye Research Centre, Centre for Ocular Regeneration, Hyderabad Eye Research Foundation, L.V. Prasad Eye Institute, Hyderabad, India
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3
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Abdul-Al M, Kyeremeh GK, Saeinasab M, Heidari Keshel S, Sefat F. Stem Cell Niche Microenvironment: Review. Bioengineering (Basel) 2021; 8:bioengineering8080108. [PMID: 34436111 PMCID: PMC8389324 DOI: 10.3390/bioengineering8080108] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 07/14/2021] [Accepted: 07/16/2021] [Indexed: 12/13/2022] Open
Abstract
The cornea comprises a pool of self-regenerating epithelial cells that are crucial to preserving clarity and visibility. Limbal epithelial stem cells (LESCs), which live in a specialized stem cell niche (SCN), are crucial for the survival of the human corneal epithelium. They live at the bottom of the limbal crypts, in a physically enclosed microenvironment with a number of neighboring niche cells. Scientists also simplified features of these diverse microenvironments for more analysis in situ by designing and recreating features of different SCNs. Recent methods for regenerating the corneal epithelium after serious trauma, including burns and allergic assaults, focus mainly on regenerating the LESCs. Mesenchymal stem cells, which can transform into self-renewing and skeletal tissues, hold immense interest for tissue engineering and innovative medicinal exploration. This review summarizes all types of LESCs, identity and location of the human epithelial stem cells (HESCs), reconstruction of LSCN and artificial stem cells for self-renewal.
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Affiliation(s)
- Mohamed Abdul-Al
- Department of Biomedical and Electronics Engineering, School of Engineering, University of Bradford, Bradford BD71DP, UK; (M.A.-A.); (G.K.K.)
| | - George Kumi Kyeremeh
- Department of Biomedical and Electronics Engineering, School of Engineering, University of Bradford, Bradford BD71DP, UK; (M.A.-A.); (G.K.K.)
| | - Morvarid Saeinasab
- Department of Biology, Faculty of Science, Ferdowsi University of Mashhad, Mashhad 91779 48974, Iran;
| | - Saeed Heidari Keshel
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran 19839 69411, Iran;
| | - Farshid Sefat
- Department of Biomedical and Electronics Engineering, School of Engineering, University of Bradford, Bradford BD71DP, UK; (M.A.-A.); (G.K.K.)
- Interdisciplinary Research Centre in Polymer Science & Technology (Polymer IRC), University of Bradford, Bradford BD71DP, UK
- Correspondence:
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4
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Schlereth SL, Hos D, Matthaei M, Hamrah P, Schmetterer L, O'Leary O, Ullmer C, Horstmann J, Bock F, Wacker K, Schröder H, Notara M, Haagdorens M, Nuijts RMMA, Dunker SL, Dickman MM, Fauser S, Scholl HPN, Wheeler-Schilling T, Cursiefen C. New Technologies in Clinical Trials in Corneal Diseases and Limbal Stem Cell Deficiency: Review from the European Vision Institute Special Interest Focus Group Meeting. Ophthalmic Res 2020; 64:145-167. [PMID: 32634808 DOI: 10.1159/000509954] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Accepted: 06/30/2020] [Indexed: 11/19/2022]
Abstract
To discuss and evaluate new technologies for a better diagnosis of corneal diseases and limbal stem cell deficiency, the outcomes of a consensus process within the European Vision Institute (and of a workshop at the University of Cologne) are outlined. Various technologies are presented and analyzed for their potential clinical use also in defining new end points in clinical trials. The disease areas which are discussed comprise dry eye and ocular surface inflammation, imaging, and corneal neovascularization and corneal grafting/stem cell and cell transplantation. The unmet needs in the abovementioned disease areas are discussed, and realistically achievable new technologies for better diagnosis and use in clinical trials are outlined. To sum up, it can be said that there are several new technologies that can improve current diagnostics in the field of ophthalmology in the near future and will have impact on clinical trial end point design.
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Affiliation(s)
- Simona L Schlereth
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany, .,Center for Molecular Medicine (CMMC) University of Cologne, Cologne, Germany,
| | - Deniz Hos
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine (CMMC) University of Cologne, Cologne, Germany
| | - Mario Matthaei
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Pedram Hamrah
- Cornea Service and Center for Translational Ocular Immunology, New England Eye Center, Department of Ophthalmology, Tufts Medical Center, Tufts University School of Medicine, Boston, Massachusetts, USA
| | - Leopold Schmetterer
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore.,SERI-NTU Advanced Ocular Engineering (STANCE), Singapore, Singapore.,Institute for Health Technologies, Nanyang Technological University, Singapore, Singapore.,School of Chemical and Biomedical Engineering, Nanyang Technological University, Singapore, Singapore.,Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria.,Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria.,Academic Clinical Program, Duke-NUS Medical School, Singapore, Singapore.,Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
| | - Olivia O'Leary
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Christoph Ullmer
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Jens Horstmann
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Felix Bock
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Katrin Wacker
- Eye Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | | | - Maria Notara
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Michel Haagdorens
- Faculty of Medicine and Health Sciences, Department of Ophthalmology, Visual Optics and Visual Rehabilitation, University of Antwerp, Antwerp, Belgium.,Department of Ophthalmology, Antwerp University Hospital, Antwerp, Belgium
| | - Rudy M M A Nuijts
- University Eye Clinic, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Suryan L Dunker
- University Eye Clinic, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Mor M Dickman
- University Eye Clinic, Maastricht University Medical Center, Maastricht, The Netherlands
| | - Sascha Fauser
- Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd., Basel, Switzerland
| | - Hendrik P N Scholl
- Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland.,Department of Ophthalmology, University of Basel, Basel, Switzerland.,Wilmer Eye Institute, Johns Hopkins University, Baltimore, Maryland, USA
| | - Thomas Wheeler-Schilling
- European Vision Institute EEIG, Brussels, Belgium.,Institute for Ophthalmic Research, University of Tuebingen, Tuebingen, Germany
| | - Claus Cursiefen
- Department of Ophthalmology, University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine (CMMC) University of Cologne, Cologne, Germany
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5
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Prina E, Amer MH, Sidney L, Tromayer M, Moore J, Liska R, Bertolin M, Ferrari S, Hopkinson A, Dua H, Yang J, Wildman R, Rose FRAJ. Bioinspired Precision Engineering of Three-Dimensional Epithelial Stem Cell Microniches. ACTA ACUST UNITED AC 2020; 4:e2000016. [PMID: 32329968 DOI: 10.1002/adbi.202000016] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Revised: 03/22/2020] [Accepted: 03/31/2020] [Indexed: 12/16/2022]
Abstract
Maintenance of the epithelium relies on stem cells residing within specialized microenvironments, known as epithelial crypts. Two-photon polymerization (2PP) is a valuable tool for fabricating 3D micro/nanostructures for stem cell niche engineering applications. Herein, biomimetic gelatin methacrylate-based constructs, replicating the precise geometry of the limbal epithelial crypt structures (limbal stem cell "microniches") as an exemplar epithelial niche, are fabricated using 2PP. Human limbal epithelial stem cells (hLESCs) are seeded within the microniches in xeno-free conditions to investigate their ability to repopulate the crypts and the expression of various differentiation markers. Cell proliferation and a zonation in cell phenotype along the z-axis are observed without the use of exogenous signaling molecules. Significant differences in cell phenotype between cells located at the base of the microniche and those situated towards the rim are observed, demonstrating that stem cell fate is strongly influenced by its location within a niche and the geometrical details of where it resides. This study provides insight into the influence of the niche's spatial geometry on hLESCs and demonstrates a flexible approach for the fabrication of biomimetic crypt-like structures in epithelial tissues. This has significant implications for regenerative medicine applications and can ultimately lead to implantable synthetic "niche-based" treatments.
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Affiliation(s)
- Elisabetta Prina
- Division of Regenerative Medicine and Cellular Therapies, School of Pharmacy, Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Mahetab H Amer
- Division of Regenerative Medicine and Cellular Therapies, School of Pharmacy, Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Laura Sidney
- Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Maximilian Tromayer
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163, Vienna, 1060, Austria
| | - Jonathan Moore
- School of Chemistry, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Robert Liska
- Institute of Applied Synthetic Chemistry, Vienna University of Technology, Getreidemarkt 9/163, Vienna, 1060, Austria
| | - Marina Bertolin
- Fondazione Banca degli Occhi del Veneto Onlus, Padiglione Rama, Via Paccagnella 11, Zelarino-Venezia, 30174, Italy
| | - Stefano Ferrari
- Fondazione Banca degli Occhi del Veneto Onlus, Padiglione Rama, Via Paccagnella 11, Zelarino-Venezia, 30174, Italy
| | - Andrew Hopkinson
- Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Harminder Dua
- Academic Ophthalmology, Division of Clinical Neuroscience, University of Nottingham, Nottingham, NG7 2UH, UK
| | - Jing Yang
- Division of Regenerative Medicine and Cellular Therapies, School of Pharmacy, Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Ricky Wildman
- Institute of Advanced Manufacturing, Faculty of Engineering, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Felicity R A J Rose
- Division of Regenerative Medicine and Cellular Therapies, School of Pharmacy, Nottingham Biodiscovery Institute, University of Nottingham, Nottingham, NG7 2RD, UK
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6
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Banayan N, Georgeon C, Grieve K, Ghoubay D, Baudouin F, Borderie V. [In vivo confocal microscopy and optical coherence tomography as innovative tools for the diagnosis of limbal stem cell deficiency (French translation of the article)]. J Fr Ophtalmol 2018; 41:968-980. [PMID: 30473234 DOI: 10.1016/j.jfo.2018.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 07/10/2018] [Accepted: 07/13/2018] [Indexed: 01/22/2023]
Abstract
The limbus is the anatomical and functional barrier between corneal and conjunctival epithelia. It is characterized by presence of the limbal stem cell niche which allows corneal homeostasis to be maintained. Limbal stem cell deficiency is characterized by a dual process: insufficient regeneration of corneal epithelium, which cannot therefore assure its function of physiological support, associated with corneal invasion by conjunctival proliferation. Diagnosis is currently made via routine clinical examination, corneal impression cytology and in vivo confocal microscopy (IVCM). Slit lamp examination shows abnormal limbal anatomy, thin and irregular epithelium with late fluorescein staining, and superficial vascularization. With its high resolution, IVCM allows identification of limbal and corneal epithelial changes at a cellular level in en face views, parallel to the corneal surface, but with a restricted viewing field of the corneal surface. It shows a poor transition between the corneal and conjunctival epithelia, associated with a loss of the normal corneal epithelial stratification, low basal cell and sub-basal nerve plexus densities, even with sub-epithelial fibrosis. Optical coherence tomography in central cornea and at the limbus, with scans in different orientations, allows a quick, global and non-invasive analysis of normal eyes and those with limbal stem cell deficiency. It shows a thin limbal epithelium, lacking normal thickening, featuring absence of stromal undulations and limbal crypts in cross-sections and sections parallel to the limbus, lack of visible limbal crypts in en face sections, loss of clear transition between the hyporeflective corneal epithelium and the hyperreflective conjunctival epithelium, and hyperreflective sub-epithelial fibrosis.
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Affiliation(s)
- N Banayan
- Service d'ophtalmologie 5, centre hospitalier national d'ophtalmologie des Quinze-Vingts, 28, rue de Charenton, 75012 Paris, France
| | - C Georgeon
- Service d'ophtalmologie 5, centre hospitalier national d'ophtalmologie des Quinze-Vingts, 28, rue de Charenton, 75012 Paris, France
| | - K Grieve
- Inserm UMR S 968, institut de la vision, Sorbonne université, CHNO des 15-20, 75012 Paris, France
| | - D Ghoubay
- Service d'ophtalmologie 5, centre hospitalier national d'ophtalmologie des Quinze-Vingts, 28, rue de Charenton, 75012 Paris, France; Inserm UMR S 968, institut de la vision, Sorbonne université, CHNO des 15-20, 75012 Paris, France
| | - F Baudouin
- Inserm UMR S 968, institut de la vision, Sorbonne université, CHNO des 15-20, 75012 Paris, France
| | - V Borderie
- Service d'ophtalmologie 5, centre hospitalier national d'ophtalmologie des Quinze-Vingts, 28, rue de Charenton, 75012 Paris, France; Inserm UMR S 968, institut de la vision, Sorbonne université, CHNO des 15-20, 75012 Paris, France.
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7
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Banayan N, Georgeon C, Grieve K, Ghoubay D, Baudouin F, Borderie V. In vivo confocal microscopy and optical coherence tomography as innovative tools for the diagnosis of limbal stem cell deficiency. J Fr Ophtalmol 2018; 41:e395-e406. [DOI: 10.1016/j.jfo.2018.09.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 09/10/2018] [Accepted: 09/12/2018] [Indexed: 12/13/2022]
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8
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Exosomes from normal and diabetic human corneolimbal keratocytes differentially regulate migration, proliferation and marker expression of limbal epithelial cells. Sci Rep 2018; 8:15173. [PMID: 30310159 PMCID: PMC6182003 DOI: 10.1038/s41598-018-33169-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/19/2018] [Indexed: 12/13/2022] Open
Abstract
Limbal epithelial stem cells (LESC) maintenance requires communication between stem cells and neighboring stromal keratocytes. Extracellular vesicles (EVs) are important for intercellular communication in various stem cell niches. We explored the regulatory roles of limbal stromal cell (LSC)-derived exosomes (Exos), an EV sub-population, in limbal epithelial cells (LEC) in normal and diabetic limbal niche and determined differences in Exo cargos from normal and diabetic LSC. Wound healing and proliferation rates in primary normal LEC were significantly enhanced upon treatment by normal Exos (N-Exos), but not by diabetic Exos (DM-Exos). Western analysis showed increased Akt phosphorylation in wounded LECs and organ-cultured corneas treated with N-Exos, compared to untreated wounded cells and DM-Exos treated fellow corneas, respectively. N-Exos treated organ-cultured corneas showed upregulation of putative LESC markers, keratin 15 (K15) and Frizzled-7, compared to the DM-Exos treated fellow corneas. By next generation sequencing, we identified differentially expressed small RNAs including microRNAs in DM-Exos vs. N-Exos. Overall, N-Exos have greater effect on LEC proliferation and wound healing than DM-Exos, likely by activating Akt signaling. The small RNA differences in Exos from diabetic vs. normal LSC could contribute to the disease state. Our study suggests that exosomes may serve as novel therapeutic tools for diabetic cornea.
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9
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Guo ZH, Zhang W, Jia YYS, Liu QX, Li ZF, Lin JS. An Insight into the Difficulties in the Discovery of Specific Biomarkers of Limbal Stem Cells. Int J Mol Sci 2018; 19:ijms19071982. [PMID: 29986467 PMCID: PMC6073450 DOI: 10.3390/ijms19071982] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 06/25/2018] [Accepted: 06/29/2018] [Indexed: 12/13/2022] Open
Abstract
Keeping the integrity and transparency of the cornea is the most important issue to ensure normal vision. There are more than 10 million patients going blind due to the cornea diseases worldwide. One of the effective ways to cure corneal diseases is corneal transplantation. Currently, donations are the main source of corneas for transplantation, but immune rejection and a shortage of donor corneas are still serious problems. Graft rejection could cause transplanted cornea opacity to fail. Therefore, bioengineer-based corneas become a new source for corneal transplantation. Limbal stem cells (LSCs) are located at the basal layer in the epithelial palisades of Vogt, which serve a homeostatic function for the cornea epithelium and repair the damaged cornea. LSC-based transplantation is one of the hot topics currently. Clinical data showed that the ratio of LSCs to total candidate cells for a transplantation has a significant impact on the effectiveness of the transplantation. It indicates that it is very important to accurately identify the LSCs. To date, several putative biomarkers of LSCs have been widely reported, whereas their specificity is controversial. As reported, the identification of LSCs is based on the characteristics of stem cells, such as a nuclear-to-cytoplasm ratio (N/C) ≥ 0.7, label-retaining, and side population (SP) phenotype. Here, we review recently published data to provide an insight into the circumstances in the study of LSC biomarkers. The particularities of limbus anatomy and histochemistry, the limits of the current technology level for LSC isolation, the heterogeneity of LSCs and the influence of enzyme digestion are discussed. Practical approaches are proposed in order to overcome the difficulties in basic and applied research for LSC-specific biomarkers.
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Affiliation(s)
- Zhi Hou Guo
- School of Medicine, Huaqiao University, Quanzhou 362021, China.
| | - Wei Zhang
- School of Medicine, Huaqiao University, Quanzhou 362021, China.
| | | | - Qing Xiu Liu
- School of Medicine, Huaqiao University, Quanzhou 362021, China.
| | - Zhao Fa Li
- School of Medicine, Huaqiao University, Quanzhou 362021, China.
| | - Jun Sheng Lin
- School of Medicine, Huaqiao University, Quanzhou 362021, China.
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10
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Saghizadeh M, Kramerov AA, Svendsen CN, Ljubimov AV. Concise Review: Stem Cells for Corneal Wound Healing. Stem Cells 2017; 35:2105-2114. [PMID: 28748596 PMCID: PMC5637932 DOI: 10.1002/stem.2667] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/16/2017] [Accepted: 07/02/2017] [Indexed: 02/06/2023]
Abstract
Corneal wound healing is a complex process that occurs in response to various injuries and commonly used refractive surgery. It is a significant clinical problem, which may lead to serious complications due to either incomplete (epithelial) or excessive (stromal) healing. Epithelial stem cells clearly play a role in this process, whereas the contribution of stromal and endothelial progenitors is less well studied. The available evidence on stem cell participation in corneal wound healing is reviewed, together with the data on the use of corneal and non-corneal stem cells to facilitate this process in diseased or postsurgical conditions. Important aspects of corneal stem cell generation from alternative cell sources, including pluripotent stem cells, for possible transplantation upon corneal injuries or in disease conditions are also presented. Stem Cells 2017;35:2105-2114.
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Affiliation(s)
- Mehrnoosh Saghizadeh
- Cedars‐Sinai Medical Center, Regenerative Medicine InstituteLos AngelesCaliforniaUSA
- David Geffen School of Medicine at UCLALos AngelesCaliforniaUSA
| | - Andrei A. Kramerov
- Cedars‐Sinai Medical Center, Regenerative Medicine InstituteLos AngelesCaliforniaUSA
| | - Clive N. Svendsen
- Cedars‐Sinai Medical Center, Regenerative Medicine InstituteLos AngelesCaliforniaUSA
- David Geffen School of Medicine at UCLALos AngelesCaliforniaUSA
| | - Alexander V. Ljubimov
- Cedars‐Sinai Medical Center, Regenerative Medicine InstituteLos AngelesCaliforniaUSA
- David Geffen School of Medicine at UCLALos AngelesCaliforniaUSA
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12
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Schlötzer-Schrehardt U, Freudenberg U, Kruse FE. Zukunftstechnologie Tissue-Engineering. Ophthalmologe 2017; 114:327-340. [DOI: 10.1007/s00347-017-0468-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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13
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Haagdorens M, Behaegel J, Rozema J, Van Gerwen V, Michiels S, Ní Dhubhghaill S, Tassignon MJ, Zakaria N. A method for quantifying limbal stem cell niches using OCT imaging. Br J Ophthalmol 2017; 101:1250-1255. [PMID: 28228408 PMCID: PMC5574400 DOI: 10.1136/bjophthalmol-2016-309549] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/16/2016] [Accepted: 12/31/2016] [Indexed: 12/13/2022]
Abstract
Aims To evaluate the efficacy of Fourier domain-optical coherence tomography (FD-OCT) in imaging and quantifying the limbal palisades of Vogt and to correlate these images with histological findings. Methods The superior and inferior limbal region of both eyes of 50 healthy volunteers were imaged by FD-OCT. Images were processed and analysed using Matlab software. In vitro immunofluorescent staining of a cadaveric donor limbus was analysed to correlate the presence of stem cells in the visualised structures. Results FD-OCT could successfully visualise limbal crypts and the palisades of Vogt in the limbus region. Fluorescent labelling confirmed the presence of stem cells in these structures. The mean palisade ridge width (ΔPR) and the mean interpalisade epithelial rete peg width (ΔERP) were both of the order of 72 μm, leading to a palisade density (PD) of about 7.4 palisades/mm. A significant difference in ΔPR, ΔERP and PD was seen between the inferior and superior sides of the right eye and the superior sides of the left and right eye(p<0.05.). A significant influence of iris colour on parameters ΔPR, ΔERP and PD was found, and of age on PD and ΔERP (p<0.05). Conclusions In vivo OCT imaging is a safe and effective modality to image the limbus and can be used to visualise the palisades of Vogt. Image processing using Matlab software enabled quantification and density calculation of imaged limbal palisades of Vogt. This technique may enhance targeted limbal biopsies for transplantation.
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Affiliation(s)
- Michel Haagdorens
- Faculty of Medicine and Health Sciences, Department of Ophthalmology, Visual Optics and Visual Rehabilitation, Antwerp University, Antwerp, Wilrijk, Belgium.,Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
| | - Joséphine Behaegel
- Faculty of Medicine and Health Sciences, Department of Ophthalmology, Visual Optics and Visual Rehabilitation, Antwerp University, Antwerp, Wilrijk, Belgium.,Department of Ophthalmology, University Hospital Brussels, Brussels, Belgium
| | - Jos Rozema
- Faculty of Medicine and Health Sciences, Department of Ophthalmology, Visual Optics and Visual Rehabilitation, Antwerp University, Antwerp, Wilrijk, Belgium.,Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
| | - Veerle Van Gerwen
- Faculty of Medicine and Health Sciences, Department of Ophthalmology, Visual Optics and Visual Rehabilitation, Antwerp University, Antwerp, Wilrijk, Belgium
| | - Sofie Michiels
- Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
| | - Sorcha Ní Dhubhghaill
- Faculty of Medicine and Health Sciences, Department of Ophthalmology, Visual Optics and Visual Rehabilitation, Antwerp University, Antwerp, Wilrijk, Belgium.,Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
| | - Marie-José Tassignon
- Faculty of Medicine and Health Sciences, Department of Ophthalmology, Visual Optics and Visual Rehabilitation, Antwerp University, Antwerp, Wilrijk, Belgium.,Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium
| | - Nadia Zakaria
- Faculty of Medicine and Health Sciences, Department of Ophthalmology, Visual Optics and Visual Rehabilitation, Antwerp University, Antwerp, Wilrijk, Belgium.,Department of Ophthalmology, Antwerp University Hospital, Edegem, Belgium.,Center for Cell Therapy and Regenerative Medicine, Antwerp University Hospital, Edegem, Belgium
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Lužnik Z, Hawlina M, Ferrari S, Ponzin D, Schollmayer P. Ocular surface reconstruction in limbal stem cell deficiency: current treatment options and perspectives. EXPERT REVIEW OF OPHTHALMOLOGY 2017. [DOI: 10.1080/17469899.2017.1263568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- Zala Lužnik
- Eye Hospital, University Medical Centre, Ljubljana, Slovenia
| | - Marko Hawlina
- Eye Hospital, University Medical Centre, Ljubljana, Slovenia
| | - Stefano Ferrari
- Fondazione Banca degli Occhi del Veneto Onlus, Via Paccagnella 11, Venezia Zelarino, Italy
| | - Diego Ponzin
- Fondazione Banca degli Occhi del Veneto Onlus, Via Paccagnella 11, Venezia Zelarino, Italy
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Abstract
: Worldwide, 45 million people are blind. Corneal blindness is a major cause of visual loss, estimated to affect 10 million. For the most difficult to treat patients, including those with a disease called limbal stem cell deficiency, a donor corneal graft is not a viable option; thus, patients are treated with specialized stem cell grafts, which fail in a significant proportion (30 to 50%) of subjects. This unacceptable failure rate means there is a pressing need to develop minimally invasive, long-lasting, cost-effective therapies to improve patient quality of life and lessen the economic burden. Restoring vision in patients with severe corneal disease is the main focus of our research program; however, to achieve our goals and deliver the best quality stem cell therapy, we must first understand the basic biology of these cells, including their residence, the factors that support their long-term existence, markers to identify and isolate them, and carriers that facilitate expansion, delivery, and protection during engraftment. We recently achieved some of these goals through the discovery of stem cell markers and the development of a novel and innovative contact lens-based cell transfer technique that has been successfully trialed on patients with corneal blindness. Although several popular methodologies are currently available to nurture and transfer stem cells to the patients' ocular surface, contact lenses provide many advantages that will be discussed in this review article. The job for clinician-researchers will be to map precisely how these cells contribute to restoring ocular health and whether improvements in the quality of cells and the cell delivery system can be developed to reduce disease burden.
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Dziasko MA, Daniels JT. Anatomical Features and Cell-Cell Interactions in the Human Limbal Epithelial Stem Cell Niche. Ocul Surf 2016; 14:322-30. [DOI: 10.1016/j.jtos.2016.04.002] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 03/31/2016] [Accepted: 04/01/2016] [Indexed: 12/13/2022]
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Eghtedari Y, Richardson A, Mai K, Heng B, Guillemin GJ, Wakefield D, Di Girolamo N. Keratin 14 Expression in Epithelial Progenitor Cells of the Developing Human Cornea. Stem Cells Dev 2016; 25:699-711. [DOI: 10.1089/scd.2016.0039] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Yas Eghtedari
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Alexander Richardson
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Kelly Mai
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Benjamin Heng
- Neuroinflammation Group, Faculty of Medicine & Health Sciences, Macquarie University, Sydney, Australia
| | - Gilles J. Guillemin
- Neuroinflammation Group, Faculty of Medicine & Health Sciences, Macquarie University, Sydney, Australia
| | - Denis Wakefield
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Nick Di Girolamo
- Ocular Diseases Research Group, School of Medical Sciences, University of New South Wales, Sydney, Australia
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Fate Mapping Mammalian Corneal Epithelia. Ocul Surf 2016; 14:82-99. [PMID: 26774909 DOI: 10.1016/j.jtos.2015.11.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 11/16/2015] [Accepted: 11/18/2015] [Indexed: 02/07/2023]
Abstract
The anterior aspect of the cornea consists of a stratified squamous epithelium, thought to be maintained by a rare population of stem cells (SCs) that reside in the limbal transition zone. Although migration of cells that replenish the corneal epithelium has been studied for over a century, the process is still poorly understood and not well characterized. Numerous techniques have been employed to examine corneal epithelial dynamics, including visualization by light microscopy, the incorporation of vital dyes and DNA labels, and transplantation of genetically marked cells that have acted as cell and lineage beacons. Modern-day lineage tracing utilizes molecular methods to determine the fate of a specific cell and its progeny over time. Classically employed in developmental biology, lineage tracing has been used more recently to track the progeny of adult SCs in a number of organs to pin-point their location and understand their movement and influence on tissue regeneration. This review highlights key discoveries that have led researchers to develop cutting-edge genetic tools to effectively and more accurately monitor turnover and displacement of cells within the mammalian corneal epithelium. Collating information on the basic biology of SCs will have clinical ramifications in furthering our knowledge of the processes that govern their role in homeostasis, wound-healing, transplantation, and how we can improve current unsatisfactory SC-based therapies for patients suffering blinding corneal disease.
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Limbal Stem Cell Deficiency: Current Treatment Options and Emerging Therapies. Stem Cells Int 2015; 2016:9798374. [PMID: 26788074 PMCID: PMC4691643 DOI: 10.1155/2016/9798374] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 08/18/2015] [Indexed: 12/15/2022] Open
Abstract
Severe ocular surface disease can result in limbal stem cell deficiency (LSCD), a condition leading to decreased visual acuity, photophobia, and ocular pain. To restore the ocular surface in advanced stem cell deficient corneas, an autologous or allogenic limbal stem cell transplantation is performed. In recent years, the risk of secondary LSCD due to removal of large limbal grafts has been significantly reduced by the optimization of cultivated limbal epithelial transplantation (CLET). Despite the great successes of CLET, there still is room for improvement as overall success rate is 70% and visual acuity often remains suboptimal after successful transplantation. Simple limbal epithelial transplantation reports higher success rates but has not been performed in as many patients yet. This review focuses on limbal epithelial stem cells and the pathophysiology of LSCD. State-of-the-art therapeutic management of LSCD is described, and new and evolving techniques in ocular surface regeneration are being discussed, in particular, advantages and disadvantages of alternative cell scaffolds and cell sources for cell based ocular surface reconstruction.
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Grieve K, Ghoubay D, Georgeon C, Thouvenin O, Bouheraoua N, Paques M, Borderie V. Three-dimensional structure of the mammalian limbal stem cell niche. Exp Eye Res 2015; 140:75-84. [DOI: 10.1016/j.exer.2015.08.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 07/24/2015] [Accepted: 08/04/2015] [Indexed: 12/13/2022]
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Chang SJ, Li S, Andreasen A, Sha XZ, Zhai XY. A reference-free method for brightness compensation and contrast enhancement of micrographs of serial sections. PLoS One 2015; 10:e0127855. [PMID: 26020531 PMCID: PMC4447386 DOI: 10.1371/journal.pone.0127855] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 04/20/2015] [Indexed: 11/18/2022] Open
Abstract
Three-dimensional (3D) reconstruction of an organ or tissue from a stack of histologic serial sections provides valuable morphological information. The procedure includes section preparation of the organ or tissue, micrographs acquisition, image registration, 3D reconstruction, and visualization. However, the brightness and contrast through the image stack may not be consistent due to imperfections in the staining procedure, which may cause difficulties in micro-structure identification using virtual sections, region segmentation, automatic target tracing, etc. In the present study, a reference-free method, Sequential Histogram Fitting Algorithm (SHFA), is therefore developed for adjusting the severe and irregular variance of brightness and contrast within the image stack. To apply the SHFA, the gray value histograms of individual images are first calculated over the entire image stack and a set of landmark gray values are chosen. Then the histograms are transformed so that there are no abrupt changes in progressing through the stack. Finally, the pixel gray values of the original images are transformed into the desired ones based on the relationship between the original and the transformed histograms. The SHFA is tested on an image stacks from mouse kidney sections stained with toluidine blue, and captured by a slide scanner. As results, the images through the entire stack reveal homogenous brightness and consistent contrast. In addition, subtle color differences in the tissue are well preserved so that the morphological details can be recognized, even in virtual sections. In conclusion, compared with the existing histogram-based methods, the present study provides a practical method suitable for compensating brightness, and improving contrast of images derived from a large number of serial sections of biological organ.
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Affiliation(s)
- Shi-Jie Chang
- Department of Biomedical Engineering, China Medical University, Shenyang, Liaoning, China
| | - Shuo Li
- Department of Biochemistry, China Medical University, Shenyang, Liaoning, China
| | - Arne Andreasen
- Department of Biomedicine—Anatomy, Aarhus University, Aarhus, Denmark
| | - Xian-Zheng Sha
- Department of Biomedical Engineering, China Medical University, Shenyang, Liaoning, China
| | - Xiao-Yue Zhai
- Department of Histology and Embryology, China Medical University, Shenyang, Liaoning, China
- * E-mail:
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Non-rigid landmark-based large-scale image registration in 3-D reconstruction of mouse and rat kidney nephrons. Micron 2014; 68:122-129. [PMID: 25464150 DOI: 10.1016/j.micron.2014.10.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Revised: 09/12/2014] [Accepted: 10/06/2014] [Indexed: 11/22/2022]
Abstract
BACKGROUND Serial histological sections are suffering from mechanical distortions that disturb the reconstruction of 3-D objects. We have corrected such artifacts with a non-rigid landmark-based method that respects the original geometry in the tissue block. The method is exemplified on a large scale in the registration of semi-thin serial sections of the mouse and rat kidneys, and has been tested on FFPE-sections. AIM In this study of mouse and rat kidneys, we have measured and characterized the deformations introduced in the preparation of 2.5-μm-thick Epon sections and then eliminated them by a landmark-based non-rigid transformation (NRT). METHODS We obtained 2.5-μm-thick serial Epon sections from three mouse kidneys and three rat kidneys for 3-D reconstruction of the nephron tubules. First, the images from 3000 serial mouse and 13,000 serial rat sections underwent a classic rigid registration (CRR), and the distortions were measured and indexed. The section images underwent a further NRT in order to compensate for the deformations. The NRT used is a classic interactive landmark-based approach. The quality of the NRT was verified by comparing the geometry of the transformed images with corresponding block images. RESULTS After CRR, the 2.5-μm-thick sections had a linear deformation of up to 2%, the tubular lengths were overestimated with up to 1.5×, and it was most difficult to trace the tubules from section to section. After the additional NRT, the geometry of the images reflected the original geometry in the block, the tubular lengths were no longer overestimated, and the NRT highly facilitated the tracing of the tubular system. CONCLUSIONS NRT has facilitated the tracing of the tubular system in kidneys, a tracing, which would otherwise have been most difficult to perform. NRT has yielded substantial new knowledge to segmental and spatial nephron organization in the mouse and rat kidneys.
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Honoré B, Vorum H. Proteomic analysis as a means to approach limbal stem cell biology in a search for stem cell markers. Proteomics Clin Appl 2014; 8:178-84. [PMID: 24497450 DOI: 10.1002/prca.201300049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 10/06/2013] [Accepted: 12/02/2013] [Indexed: 12/13/2022]
Abstract
The cornea consists of three main layers: an outer surface epithelium, the stroma, and the endothelium. A clear cornea is necessary for optimal vision and is maintained and repaired from limbal epithelial stem cells located in the limbus between the cornea and the sclera. Diseases and injury may result in deficiency of the stem cells impairing their ability to renew the corneal epithelium. Patients with limbal stem cell deficiency experience chronic pain and ultimately blindness. Attempts to treat the disease are based on replacement of the stem cells by transplantation or by culturing the stem cells. We here review the proteomic techniques that so far have been used to approach characterization of limbal stem cells and markers to identify them. It is apparent that the field is in a rather inchoate state due to the scarcity and relative inaccessibility of the stem cells. However, the importance of revealing limbal stem cell biology and identifying stem cell biomarkers calls for greater use of emerging methodology. Strategies for future studies are discussed.
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Affiliation(s)
- Bent Honoré
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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Christensen EI, Grann B, Kristoffersen IB, Skriver E, Thomsen JS, Andreasen A. Three-dimensional reconstruction of the rat nephron. Am J Physiol Renal Physiol 2014; 306:F664-71. [PMID: 24477686 DOI: 10.1152/ajprenal.00522.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
This study gives a three-dimensional (3D) structural analysis of rat nephrons and their connections to collecting ducts. Approximately 4,500 2.5-μm-thick serial sections from the renal surface to the papillary tip were obtained from each of 3 kidneys of Wistar rats. Digital images were recorded and aligned into three image stacks and traced from image to image. Short-loop nephrons (SLNs), long-loop nephrons (LLNs), and collecting ducts (CDs) were reconstructed in 3D. We identified a well-defined boundary between the outer stripe and the inner stripe of the outer medulla corresponding to the transition of descending thick limbs to descending thin limbs and between the inner stripe and the inner medulla, i.e., the transition of ascending thin limbs into ascending thick limbs of LLNs. In all nephrons, a mosaic pattern of proximal tubule (PT) cells and descending thin limb (DTL) cells was observed at the transition between the PT and the DTL. The course of the LLNs revealed tortuous proximal "straight" tubules and winding of the DTLs within the outer half of the inner stripe. The localization of loop bends of SLNs in the inner stripe of the outer medulla and the bends of LLNs in the inner medulla reflected the localization of their glomeruli; i.e., the deeper the glomerulus, the deeper the bend. Each CD drained approximately three to six nephrons with a different pattern than previously established in mice. This information will provide a basis for evaluation of structural changes within nephrons as a result of physiological or pharmaceutical intervention.
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Affiliation(s)
- Erik I Christensen
- Dept. of Biomedicine, Anatomy Section of Cell Biology, Univ. of Aarhus, DK-8000 Aarhus C, Denmark.
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