1
|
Frigelli M, Büchler P, Kling S. Dynamic evaluation of corneal cross-linking and osmotic diffusion effects using optical coherence elastography. Sci Rep 2024; 14:16614. [PMID: 39025900 PMCID: PMC11258322 DOI: 10.1038/s41598-024-67278-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Accepted: 07/09/2024] [Indexed: 07/20/2024] Open
Abstract
Dynamic deformation events induced by osmosis or photochemical stiffening substantially influence geometrical and mechanical assessments in post-mortem corneas, therefore need to be carefully monitored in experimental settings. In this study, we employed optical coherence elastography (OCE) to quantify dynamic deformation processes at high resolution in freshly enucleated porcine corneas. Osmotic effects were studied by immerging n = 9 eyes in preservation media of three different tonicities. Dynamic processes underlying corneal cross-linking (CXL) were studied by subjecting n = 6 eyes to standard Dresden treatment, while three control groups were used. The entire procedures were performed under an OCE setup during up to 80 min, acquiring a volumetric scan every 20 s. Changes in OCE-derived axial deformations were incrementally calculated between consecutive scans. Preservation conditions had a strong influence on the observed strain patterns, which were consistent with the tonicity of the medium (swelling in hypotonic, deswelling in hypertonic environment). In the CXL group, we observed deswelling of the anterior stroma 10 min after starting the UV irradiation, which was not observed in any control group (p = 0.007). The presented results proved OCE to be a valuable technique to quantify subtle dynamic biomechanical alterations in the cornea resulting from CXL and preservation solutions.
Collapse
Affiliation(s)
- Matteo Frigelli
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Philippe Büchler
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland
| | - Sabine Kling
- ARTORG Center for Biomedical Engineering Research, University of Bern, Bern, Switzerland.
| |
Collapse
|
2
|
Advani J, Mehta PA, Hamel AR, Mehrotra S, Kiel C, Strunz T, Corso-Díaz X, Kwicklis M, van Asten F, Ratnapriya R, Chew EY, Hernandez DG, Montezuma SR, Ferrington DA, Weber BHF, Segrè AV, Swaroop A. QTL mapping of human retina DNA methylation identifies 87 gene-epigenome interactions in age-related macular degeneration. Nat Commun 2024; 15:1972. [PMID: 38438351 PMCID: PMC10912779 DOI: 10.1038/s41467-024-46063-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 02/12/2024] [Indexed: 03/06/2024] Open
Abstract
DNA methylation provides a crucial epigenetic mark linking genetic variations to environmental influence. We have analyzed array-based DNA methylation profiles of 160 human retinas with co-measured RNA-seq and >8 million genetic variants, uncovering sites of genetic regulation in cis (37,453 methylation quantitative trait loci and 12,505 expression quantitative trait loci) and 13,747 DNA methylation loci affecting gene expression, with over one-third specific to the retina. Methylation and expression quantitative trait loci show non-random distribution and enrichment of biological processes related to synapse, mitochondria, and catabolism. Summary data-based Mendelian randomization and colocalization analyses identify 87 target genes where methylation and gene-expression changes likely mediate the genotype effect on age-related macular degeneration. Integrated pathway analysis reveals epigenetic regulation of immune response and metabolism including the glutathione pathway and glycolysis. Our study thus defines key roles of genetic variations driving methylation changes, prioritizes epigenetic control of gene expression, and suggests frameworks for regulation of macular degeneration pathology by genotype-environment interaction in retina.
Collapse
Affiliation(s)
- Jayshree Advani
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Puja A Mehta
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Andrew R Hamel
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Sudeep Mehrotra
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Boston, MA, USA
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
- Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Christina Kiel
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Tobias Strunz
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Ximena Corso-Díaz
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Madeline Kwicklis
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Freekje van Asten
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Rinki Ratnapriya
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Emily Y Chew
- Division of Epidemiology and Clinical Applications, Clinical Trials Branch, National Eye Institute, National Institutes of Health, Bethesda, MD, USA
| | - Dena G Hernandez
- Laboratory of Neurogenetics, National Institute of Aging, National Institutes of Health, Bethesda, MD, USA
| | - Sandra R Montezuma
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, USA
| | - Deborah A Ferrington
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, MN, USA
- Doheny Eye Institute, Pasadena, CA, USA
| | - Bernhard H F Weber
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
- Institute of Clinical Human Genetics, University Hospital Regensburg, Regensburg, Germany
| | - Ayellet V Segrè
- Ocular Genomics Institute, Department of Ophthalmology, Massachusetts Eye and Ear, Boston, MA, USA.
- Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
- Broad Institute of MIT and Harvard, Cambridge, MA, USA.
| | - Anand Swaroop
- Neurobiology, Neurodegeneration and Repair Laboratory, National Eye Institute, National Institutes of Health, Bethesda, MD, USA.
| |
Collapse
|
3
|
Nambiar MH, Seiler TG, Senti S, Liechti L, Müller F, Studer H, Roy AS, Büchler P. Depth-dependent mechanical properties of the human cornea by uniaxial extension. Exp Eye Res 2023; 237:109718. [PMID: 37952725 DOI: 10.1016/j.exer.2023.109718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/13/2023] [Accepted: 11/06/2023] [Indexed: 11/14/2023]
Abstract
The purpose of this study was to investigate the depth-dependent biomechanical properties of the human corneal stroma under uniaxial tensile loading. Human stroma samples were obtained after the removal of Descemet's membrane in the course of Descemet's membrane endothelial keratoplasty (DMEK) transplantation. Uniaxial tensile tests were performed at three different depths: anterior, central, and posterior on 2 × 6 × 0.15 mm strips taken from the central DMEK graft. The measured force-displacement data were used to calculate stress-strain curves and to derive the tangent modulus. The study showed that mechanical strength decreased significantly with depth. The anterior cornea appeared to be the stiffest, with a stiffness approximately 18% higher than that of the central cornea and approximately 38% higher than that of the posterior layer. Larger variations in mechanical response were observed in the posterior group, probably due to the higher degree of alignment of the collagen fibers in the posterior sections of the cornea. This study contributes to a better understanding of the biomechanical tensile properties of the cornea, which has important implications for the development of new treatment strategies for corneal diseases. Accurate quantification of tensile strength as a function of depth is critical information that is lacking in human corneal biomechanics to develop numerical models and new treatment methods.
Collapse
Affiliation(s)
- Malavika H Nambiar
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, 3010, Bern, Switzerland.
| | - Theo G Seiler
- IROC AG, Institut für Refraktive und Ophthalmo-Chirurgie, Stockerstrasse 37, 8002, Zürich, Switzerland; Universitätsklinik für Augenheilkunde, Inselspital Bern, Freiburgstrasse 15, 3010, Bern, Switzerland; Klinik für Augenheilkunde, Universitätsklinikum Düsseldorf, Moorenstr, 540225, Düsseldorf, Germany.
| | - Sebastian Senti
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, 3010, Bern, Switzerland.
| | - Layko Liechti
- Ziemer Ophthalmic Systems AG, Allmendstrasse 11, 2562, Port, Switzerland.
| | - Fabian Müller
- Ziemer Ophthalmic Systems AG, Allmendstrasse 11, 2562, Port, Switzerland.
| | - Harald Studer
- Optimo Medical, Robert-Walser-Platz 7, 2503, Biel, Switzerland.
| | - Abhijit S Roy
- Narayana Nethralaya Eye Clinic, Bengaluru, Karnataka, 560010, India.
| | - Philippe Büchler
- ARTORG Center for Biomedical Engineering Research, University of Bern, Freiburgstrasse 3, 3010, Bern, Switzerland.
| |
Collapse
|
4
|
Advani J, Corso-Diaz X, Kwicklis M, van Asten F, Ratnapriya R, Mehta P, Hamel A, Mahrotra S, Segrè A, Kiel C, Strunz T, Weber B, Chew E, Hernandez D, Montezuma S, Ferrington D, Swaroop A. QTL mapping of human retina DNA methylation identifies 87 gene-epigenome interactions in age-related macular degeneration. RESEARCH SQUARE 2023:rs.3.rs-3011096. [PMID: 37398472 PMCID: PMC10312909 DOI: 10.21203/rs.3.rs-3011096/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
DNA methylation (DNAm) provides a crucial epigenetic mark linking genetic variations to environmental influence. We analyzed array-based DNAm profiles of 160 human retinas with co-measured RNA-seq and > 8 million genetic variants, uncovering sites of genetic regulation in cis (37,453 mQTLs and 12,505 eQTLs) and 13,747 eQTMs (DNAm loci affecting gene expression), with over one-third specific to the retina. mQTLs and eQTMs show non-random distribution and enrichment of biological processes related to synapse, mitochondria, and catabolism. Summary data-based Mendelian randomization and colocalization analyses identify 87 target genes where methylation and gene-expression changes likely mediate the genotype effect on age-related macular degeneration (AMD). Integrated pathway analysis reveals epigenetic regulation of immune response and metabolism including the glutathione pathway and glycolysis. Our study thus defines key roles of genetic variations driving methylation changes, prioritizes epigenetic control of gene expression, and suggests frameworks for regulation of AMD pathology by genotype-environment interaction in retina.
Collapse
Affiliation(s)
| | | | | | | | | | - Puja Mehta
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Andrew Hamel
- Department of Ophthalmology, Massachusetts Eye and Ear
| | | | | | | | | | | | - Emily Chew
- National Eye Institute/National Institutes of Health
| | | | | | | | - Anand Swaroop
- National Eye Institute, National Institutes of Health
| |
Collapse
|
5
|
Hamon L, Quintin A, Mäurer S, Weinstein I, Langenbucher A, Seitz B, Daas L. Reliability and efficiency of corneal thickness measurements using sterile donor tomography in the eye bank. Cell Tissue Bank 2022; 23:695-706. [PMID: 34773544 PMCID: PMC9675654 DOI: 10.1007/s10561-021-09980-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 11/07/2021] [Indexed: 10/19/2022]
Abstract
To evaluate the reliability and efficiency of sterile pachymetric measurements of donor corneas based on tomographic data using two different methods: a "manual" and a "(semi-)automated" method. Twenty-five (25) donor corneas (50%) stored in MI and 25 (50%) in MII were imaged 5 times consecutively using an anterior segment OCT (AS-OCT). The central corneal thickness (CCT) was measured both with the manual measurement tool of the AS-OCT (= CCTm) and with a MATLAB self-programmed software allowing (semi-)automated analysis (= CCTa). We analyzed the reliability of CCTm and CCTa using Cronbach´s alpha (α) and Wilcoxon signed-Rank Test. Concerning CCTm, 68 measurements (54.4%) in MI and 46 (36.8%) in MII presented distortions in the imaged 3D-volumes and were discarded. Concerning CCTa, 5 (4%) in MI and 1 (0.8%) in MII were not analyzable. The mean (± SD) CCTm was 1129 ± 6.8 in MI and 820 ± 5.1 µm in MII. The mean CCTa was 1149 ± 2.7 and 811 ± 2.4 µm, respectively. Both methods showed a high reliability with a Cronbach´s α for CCTm of 1.0 (MI/MII) and for CCTa of 0.99 (MI) and 1.0 (MII). Nevertheless, the mean SD of the 5 measurements was significantly higher for CCTm compared to CCTa in MI (p = 0.03), but not in MII (p = 0.92). Sterile donor tomography proves to be highly reliable for assessment of CCT with both methods. However, due to frequent distortions regarding the manual method, the (semi-)automated method is more efficient and should be preferred.
Collapse
Affiliation(s)
- Loïc Hamon
- Department of Ophthalmology, Saarland University Medical Center (UKS), Kirrberger Straße 100, Bldg. 22, 66421 Homburg/Saar, Germany
| | - Adrien Quintin
- Department of Ophthalmology, Saarland University Medical Center (UKS), Kirrberger Straße 100, Bldg. 22, 66421 Homburg/Saar, Germany
| | - Stephanie Mäurer
- Institute of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany
| | - Isabel Weinstein
- Department of Ophthalmology, Saarland University Medical Center (UKS), Kirrberger Straße 100, Bldg. 22, 66421 Homburg/Saar, Germany
| | - Achim Langenbucher
- Institute of Experimental Ophthalmology, Saarland University, Homburg/Saar, Germany
| | - Berthold Seitz
- Department of Ophthalmology, Saarland University Medical Center (UKS), Kirrberger Straße 100, Bldg. 22, 66421 Homburg/Saar, Germany
| | - Loay Daas
- Department of Ophthalmology, Saarland University Medical Center (UKS), Kirrberger Straße 100, Bldg. 22, 66421 Homburg/Saar, Germany
| |
Collapse
|
6
|
Overview of Short-Term and Intermediate-Term Corneal Storage Solution: Comparison of Clinical Outcomes and Need For Future Research. Eye Contact Lens 2022; 48:141-148. [PMID: 35296625 DOI: 10.1097/icl.0000000000000875] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/09/2021] [Indexed: 11/26/2022]
Abstract
ABSTRACT Corneal donor tissue preservation techniques have incrementally improved since the introduction of McCarey-Kaufman storage solution from short-term storage to intermediate duration of storage with the advent of organ culture and Optisol GS storage solutions. Improved understanding of the corneal endothelial cell physiology has helped in designing newer storage solutions, such as the Life 4C and Cornea Cold. The incorporation of antibiotics, ATP precursors, minerals, and vitamins has improved the viability of tissues. In addition, these modifications to the newer storage solutions have increased the endothelial longevity and metabolic activity. Despite these advances, the duration of tissue storage has largely been restricted to 2 weeks in Optisol GS and 4 weeks in organ culture. The role and cost-effectiveness of antifungal supplementation and the need for improved epithelial preservation are additional areas that need to be explored. This review intends to summarize the efficacy and viability of donor corneas in different tissue storage solution and compare clinical outcomes while providing an insight into the challenges in developing newer methods of corneal preservation.
Collapse
|
7
|
Comparison of clinical outcomes after precut DMEK with or without dextran-containing medium compared to standard DMEK: a prospective pilot study. Int Ophthalmol 2021; 42:401-409. [PMID: 34674086 DOI: 10.1007/s10792-021-02056-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 09/21/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE To investigate the clinical outcome and complication rate of precut Descemet membrane endothelial keratoplasty (DMEK) in two different culture conditions, dextran-containing and dextran-free medium, and compare the results with the current standard DMEK procedure. METHODS A prospective study of 32 eyes suffering from Fuchs endothelial dystrophy were scheduled for DMEK with a follow-up of one year. The eyes were divided into four subgroups. Group + D (n = 7) received a precut DMEK stored in dextran-containing transport medium, and Group - D (n = 9) received a precut DMEK without dextran-containing medium. The respective fellow eyes received a standard DMEK (S) (preparation directly prior to surgery) stored in dextran-containing medium (S-D + ; n = 7) or without (S-D-; n = 9). RESULTS Clinical outcome (visual acuity, endothelial cell count, central corneal thickness) and rebubbling rate were comparable for all four groups. None of the patients had a graft failure. CONCLUSION The preliminary data of the pilot study show that precut liquid-bubble DMEK leads to comparable clinical results regardless of dextran-containing or dextran-free organ culture medium and is further comparable to the standard DMEK procedure.
Collapse
|
8
|
Thickness and Curvature Changes of Human Corneal Grafts in Dextran-Containing Organ Culture Medium Before Keratoplasty. Cornea 2020; 40:733-740. [PMID: 33290320 DOI: 10.1097/ico.0000000000002543] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 08/07/2020] [Indexed: 11/25/2022]
Abstract
PURPOSE To determine the changes of corneal thickness and curvature of human corneal grafts in organ culture medium II, containing dextran T500 6%, before keratoplasty. METHODS We examined the tomography of 24 corneas from our eye bank transferred from medium I into medium II. Images were repeated hourly during 24 hours using an anterior segment optical coherence tomography. The central corneal thickness (CCT) was measured with the manual measurement tool of the anterior segment optical coherence tomography. The radii of curvature (anterior flat and steep and posterior flat and steep) were measured with a MATLAB self-programmed software for "sterile donor tomography." RESULTS The mean CCT (±SD) at baseline (T0) was 727 ± 156 μm. It reached 581 ± 103, 506 ± 84, 472 ± 79, and 456±7 μm after 6, 12, 18, and 24 hours, respectively. After 12 hours, 83% of the final deswelling was achieved. The radii of curvature (±SD) at baseline (T0) were (posterior flat, posterior steep, anterior flat, and anterior steep) 6.6 ± 0.5, 6.2 ± 0.5, 7.7 ± 0.4, and 7.4 ± 0.4 mm, respectively. After 24 hours, the radii of curvature reached 6.8 ± 0.1, 6.6 ± 0.3, 7.6 ± 0.1, and 7.4 ± 0.2 mm, respectively. CONCLUSIONS The kinetics of the deswelling process in medium II follow a hyperbolic curve. Considering a CCT of 506 μm at T12, we assume that a time interval of 12 hours in medium II might be enough for clinical purposes. This result might help to keep storage in medium II as short as possible to escape potential toxic effects of dextran in medium II. The radius of curvature does not seem to change within 24 hours for all measured surfaces.
Collapse
|
9
|
Strunz T, Kiel C, Grassmann F, Ratnapriya R, Kwicklis M, Karlstetter M, Fauser S, Arend N, Swaroop A, Langmann T, Wolf A, Weber BHF. A mega-analysis of expression quantitative trait loci in retinal tissue. PLoS Genet 2020; 16:e1008934. [PMID: 32870927 PMCID: PMC7462281 DOI: 10.1371/journal.pgen.1008934] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Accepted: 06/15/2020] [Indexed: 01/22/2023] Open
Abstract
Significant association signals from genome-wide association studies (GWAS) point to genomic regions of interest. However, for most loci the causative genetic variant remains undefined. Determining expression quantitative trait loci (eQTL) in a disease relevant tissue is an excellent approach to zoom in on disease- or trait-associated association signals and hitherto on relevant disease mechanisms. To this end, we explored regulation of gene expression in healthy retina (n = 311) and generated the largest cis-eQTL data set available to date. Genotype- and RNA-Seq data underwent rigorous quality control protocols before FastQTL was applied to assess the influence of genetic markers on local (cis) gene expression. Our analysis identified 403,151 significant eQTL variants (eVariants) that regulate 3,007 genes (eGenes) (Q-Value < 0.05). A conditional analysis revealed 744 independent secondary eQTL signals for 598 of the 3,007 eGenes. Interestingly, 99,165 (24.71%) of all unique eVariants regulate the expression of more than one eGene. Filtering the dataset for eVariants regulating three or more eGenes revealed 96 potential regulatory clusters. Of these, 31 harbour 130 genes which are partially regulated by the same genetic signal. To correlate eQTL and association signals, GWAS data from twelve complex eye diseases or traits were included and resulted in identification of 80 eGenes with potential association. Remarkably, expression of 10 genes is regulated by eVariants associated with multiple eye diseases or traits. In conclusion, we generated a unique catalogue of gene expression regulation in healthy retinal tissue and applied this resource to identify potentially pleiotropic effects in highly prevalent human eye diseases. Our study provides an excellent basis to further explore mechanisms of various retinal disease etiologies. The retina is a multilayered and highly specified neural tissue crucial for high-resolution visual perception and spatial orientation. Environmental and genetic insults to the retina result in many blinding diseases, such as age-related macular degeneration or glaucoma. Commonly, many of these diseases are age-related suggesting that minor changes are accumulating over a life-time, with little or no contribution of strong individual effects. Specifically, this is true for genetic factors known to underlie the etiology of complex diseases including the prevalent eye diseases. In our study, we searched for effects on gene expression due to genetic variation using 311 healthy post-mortem retinal tissue samples. We show that 3,007 of the 16,766 genes investigated are regulated in the retina by genetic variations. Of these, 80 genes are potentially associated to one or more of twelve complex eye diseases or retinal traits tested. Interestingly, 10 genes appear to be involved in the development of several eye traits suggesting that cellular mechanisms may act at a common point in the disease process. Consequently, our study provides the basis to further explore retinal disease pathways and is likely to highlight target molecules for future therapeutic applications.
Collapse
Affiliation(s)
- Tobias Strunz
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Christina Kiel
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
| | - Felix Grassmann
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Rinki Ratnapriya
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, Bethesda, United States of America
| | - Madeline Kwicklis
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, Bethesda, United States of America
| | - Marcus Karlstetter
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Sascha Fauser
- Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Basel, Switzerland
| | - Nicole Arend
- Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany
| | - Anand Swaroop
- Neurobiology-Neurodegeneration & Repair Laboratory, National Eye Institute, Bethesda, United States of America
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
| | - Armin Wolf
- Department of Ophthalmology, University of Ulm, Ulm, Germany
| | - Bernhard H. F. Weber
- Institute of Human Genetics, University of Regensburg, Regensburg, Germany
- Institute of Clinical Human Genetics, University Hospital Regensburg, Regensburg, Germany
- * E-mail:
| |
Collapse
|
10
|
McKay TB, Ford A, Wang S, Cairns DM, Parker RN, Deardorff PM, Ghezzi CE, Kaplan DL. Assembly and Application of a Three-Dimensional Human Corneal Tissue Model. ACTA ACUST UNITED AC 2020; 81:e84. [PMID: 31529796 DOI: 10.1002/cptx.84] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The cornea provides a functional barrier separating the outside environment from the intraocular environment, thereby protecting posterior segments of the eye from infection and damage. Pathological changes that compromise the structure or integrity of the cornea may occur as a result of injury or disease and can lead to debilitating effects on visual acuity. Over 10 million people worldwide are visually impaired or blind due to corneal opacity. Thus, physiologically relevant in vitro approaches to predict corneal toxicity of chemicals or effective treatments for disease prior to ocular exposure, as well as to study the corneal effects of systemic, chronic conditions, such as diabetes, are needed to reduce use of animal testing and accelerate therapeutic development. We have previously bioengineered an innervated corneal tissue model using silk protein scaffolds to recapitulate the structural and mechanical elements of the anterior cornea and to model the functional aspects of corneal sensation with the inclusion of epithelial, stromal, and neural components. The purpose of this unit is to provide a step-by-step guide for preparation, assembly, and application of this three-dimensional corneal tissue system to enable the study of corneal tissue biology. © 2019 by John Wiley & Sons, Inc.
Collapse
Affiliation(s)
- Tina B McKay
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Andrew Ford
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Siran Wang
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Dana M Cairns
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Rachael N Parker
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Phillip M Deardorff
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - Chiara E Ghezzi
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| | - David L Kaplan
- Department of Biomedical Engineering, Tufts University, Medford, Massachusetts
| |
Collapse
|
11
|
Pradhan KR, Reinstein DZ, Vida RS, Archer TJ, Dhungel S, Dhungana P, Carp GI. Femtosecond Laser-Assisted Small Incision Sutureless Intrastromal Lamellar Keratoplasty (SILK) for Corneal Transplantation in Keratoconus. J Refract Surg 2020; 35:663-671. [PMID: 31610008 DOI: 10.3928/1081597x-20190826-01] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 08/26/2019] [Indexed: 11/20/2022]
Abstract
PURPOSE To describe a femtosecond laser-assisted small incision sutureless intrastromal lamellar keratoplasty in an eye with severe keratoconus and report on the outcome with a 1-year follow-up. METHODS A 20-year-old man with a history of keratoconus presented for evaluation at the Tilganga Institute of Ophthalmology, Kathmandu, Nepal. The patient had previously undergone a deep anterior lamellar keratoplasty in the left eye. Examination of the right eye revealed an uncorrected distance visual acuity (UDVA) of counting fingers with a manifest refraction of -5.00 -3.50 × 170, giving a corrected distance visual acuity (CDVA) of 20/80. Thinnest pachymetry was 425 µm and progression of both anterior and posterior corneal elevation tomography and maximum keratometry was noted compared to examination 2 years prior. The VisuMax femtosecond laser (Carl Zeiss Meditec, Jena, Germany) was used to prepare the donor and recipient cornea. The donor graft was inserted into the recipient through the 3-mm small incision. No sutures were applied. RESULTS At 2 weeks postoperatively, UDVA was 20/50 with a manifest refraction of -1.00 -5.00 × 145 (20/32). One year postoperatively, UDVA was 20/80 with a manifest refraction of -2.50 -3.50 × 125 (20/40-2), with the maximum keratometry decreasing from 64.08 to 56.74 diopters. CONCLUSIONS This femtosecond laser-assisted sutureless intrastromal corneal transplantation technique may provide an option to improve the quality of vision for some patients with keratoconus, affording a simpler postoperative follow-up course compared to traditional anterior lamellar or full-thickness corneal transplantation. [J Refract Surg. 2019;35(10):663-671.].
Collapse
|
12
|
A new approach to extend the storage of donor corneas after 28 days of corneal culture in an Italian eye bank. Cell Tissue Bank 2019; 21:47-55. [PMID: 31782073 DOI: 10.1007/s10561-019-09795-2] [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: 07/26/2019] [Accepted: 11/23/2019] [Indexed: 10/25/2022]
Abstract
This study aimed to evaluate the possibility to extend the storage of unused organ-cultured donor corneas. After 28 days of corneal culture in TISSUE-C (AL.CHI.MI.A. S.R.L., Italy) and 5-day storage in transport/deswelling medium CARRY-C (AL.CHI.MI.A. S.R.L., Italy), 25 corneas that were deemed suitable for transplantation were transferred in fresh TISSUE-C at 31 °C for additional 7 days and then in fresh CARRY-C at room temperature for 24 h. Tissues were assessed for endothelial cell density (ECD), endothelial mortality and morphology after the standard and the extended corneal storage. In addition, the effect of donor age < 85 years and ≥ 85 years on corneal characteristics was assessed. After the extended storage, 6 out of 25 tested corneas (24%) showed ECD values below the acceptance limit (< 2000 cells/mm2). 19 corneas (76%) were still suitable for transplantation and showed a 5.9% loss in ECD, which was not statistically significant (P = 0.0949) compared to standard storage period. The two donor age groups did not show statistically significant differences in any tested parameter, although a trend for lower ECD and higher mortality in Descemet's folds after standard storage was observed in the ≥ 85 age donor group. Thus, the attempt of the current study to provide new sight-restorative options for unused tissues and increasing the availability of corneas in case of shortage gave encouraging results. Although a higher vulnerability of corneas from very old donors could not be statistically demonstrated in the present study, higher sample size could be required for prolonging the shelf life of these tissues.
Collapse
|
13
|
Abdin A, Daas L, Pattmöller M, Suffo S, Langenbucher A, Seitz B. Negative impact of dextran in organ culture media for pre-stripped tissue preservation on DMEK (Descemet membrane endothelial keratoplasty) outcome. Graefes Arch Clin Exp Ophthalmol 2018; 256:2135-2142. [DOI: 10.1007/s00417-018-4088-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 06/14/2018] [Accepted: 07/26/2018] [Indexed: 10/28/2022] Open
|
14
|
Lawman S, Madden PW, Romano V, Dong Y, Mason S, Williams BM, Kaye SB, Willoughby CE, Harding SP, Shen YC, Zheng Y. Deformation velocity imaging using optical coherence tomography and its applications to the cornea. BIOMEDICAL OPTICS EXPRESS 2017; 8:5579-5593. [PMID: 29296489 PMCID: PMC5745104 DOI: 10.1364/boe.8.005579] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 05/07/2023]
Abstract
Optical coherence tomography (OCT) can monitor human donor corneas non-invasively during the de-swelling process following storage for corneal transplantation, but currently only resultant thickness as a function of time is extracted. To visualize and quantify the mechanism of de-swelling, we present a method exploiting the nanometer sensitivity of the Fourier phase in OCT data to image deformation velocities. The technique was demonstrated by non-invasively showing during de-swelling that osmotic flow through an intact epithelium is negligible and removing the endothelium approximately doubled the initial flow at that interface. The increased functional data further enabled the validation of a mathematical model of the cornea. Included is an efficient method of measuring high temporal resolution (1 minute demonstrated) corneal thickness, using automated collection and semi-automated graph search segmentation. These methods expand OCT capabilities to measure volume change processes for tissues and materials.
Collapse
Affiliation(s)
- Samuel Lawman
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Peter W. Madden
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Vito Romano
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
- St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool L7 8XP, UK
| | - Yue Dong
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK
| | - Sharon Mason
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Bryan M. Williams
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| | - Stephen B. Kaye
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
- St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool L7 8XP, UK
| | - Colin E. Willoughby
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
- St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool L7 8XP, UK
| | - Simon P. Harding
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
- St. Paul's Eye Unit, Royal Liverpool University Hospital, Liverpool L7 8XP, UK
| | - Yao-Chun Shen
- Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool, L69 3GJ, UK
| | - Yalin Zheng
- Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, L7 8TX, UK
| |
Collapse
|
15
|
Filev F, Oezcan C, Feuerstacke J, Linke SJ, Wulff B, Hellwinkel OJC. Semi-quantitative assessments of dextran toxicity on corneal endothelium: conceptual design of a predictive algorithm. Cell Tissue Bank 2016; 18:91-98. [DOI: 10.1007/s10561-016-9596-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 10/24/2016] [Indexed: 10/20/2022]
|
16
|
Role of the Endothelial Layer in the Deswelling Process of Organ-Cultured Human Corneas Before Transplantation. Cornea 2016; 35:1216-21. [DOI: 10.1097/ico.0000000000000937] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
17
|
Single-Pass Dissection of Ultrathin Organ-Cultured Endothelial Lamellae Using an Innovative Microkeratome System. Cornea 2016; 35:100-4. [DOI: 10.1097/ico.0000000000000678] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
18
|
Dehydration of corneal anterior donor tissue with polyethylene glycol (PEG)-enriched media. Cell Tissue Bank 2014; 16:399-409. [PMID: 25432155 DOI: 10.1007/s10561-014-9484-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 11/21/2014] [Indexed: 10/24/2022]
Abstract
Anterior donor grafts (including scleral rim, without Descemet membrane) increase in thickness and become hazy upon storage in organ culture (OC) medium. Transfer of these grafts to standard dehydration media just before transplantation does not reduce their thickness to normal. Therefore, we assessed the efficacy of different media enriched with polyethylene glycol (PEG) as dehydrating agents for organ-cultured anterior donor grafts. Grafts were harvested and stored in the commercial OC medium 'Max' (without dextran) for 1 week, and subsequently dehydrated in the standard commercial dehydration medium 'Jet' (with dextran) supplemented with 4-20% PEG3350, or 'Max' supplemented with 20% PEG6000 and PEG20.000, or 5-20% PEG35.000. Central corneal thickness (CCT), as assessed by anterior segment-optical coherence tomography, and transparency were evaluated before, and at 1, 4 and 7 days of dehydration. Transfer of grafts after 1 week of OC (average 1,200 µm) to 'Jet' supplemented with PEG3350 revealed a concentration-dependent effect of dehydration; CCT was restored to normal (500-600 µm) when 10% PEG3350 was added. However, transparency was only temporarily restored; after 1 day, the grafts turned hazy. In contrast, grafts transferred to 'Max' supplemented with 20% PEG35.000 were transparent throughout the evaluation period, but were dehydrated to beyond normal levels (average 300 µm). 'Max' supplemented with 5% PEG35.000 dehydrated grafts to normal values and restored transparency throughout. Thus, dehydration of anterior donor grafts prior to surgery in dextran-free OC medium supplemented with 5% PEG35.000 reduces graft thickness to normal and may facilitate anterior keratoplasty procedures.
Collapse
|
19
|
Gene transfer of integration defective anti-HSV-1 meganuclease to human corneas ex vivo. Gene Ther 2014; 21:272-81. [PMID: 24430237 DOI: 10.1038/gt.2013.82] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2013] [Revised: 10/31/2013] [Accepted: 12/03/2013] [Indexed: 01/18/2023]
Abstract
Corneal graft rejection is a major problem in chronic herpetic keratitis (HK) patients with latent infection. A new class of antiviral agents targeting latent and active forms of herpes simplex virus type 1 (HSV-1) is importantly required. Meganucleases are sequence-specific homing endonucleases capable of inducing DNA double-strand breaks. A proof-of-concept experiment has shown that tailor-made meganucleases are efficient against HSV-1 in vitro. To take this work a step forward, we hypothesized that the pre-treatment of human corneas in eye banks using meganuclease-encoding vectors will allow HK patients to receive a medicated cornea to resist the recurrence of the infection and the common graft rejection problem. However, this strategy requires efficient gene delivery to human corneal endothelium. Using recombinant adeno-associated virus, serotype 2/1 (rAAV2/1), efficient gene delivery of a reporter gene was demonstrated in human corneas ex vivo. The optimum viral dose was 3.7 × 10(11) VG with an exposure time of 1 day, followed by 6 days incubation in de-swelling medium. In addition, 12 days incubation can result in transgene expression in excess of 70%. Using similar transduction conditions, meganuclease transgene expression was detected in 39.4% of the endothelial cells after 2 weeks in culture. Reduction of the total viral load in the media and the endothelial cells of corneas infected with HSV-1 was shown. Collectively, this work provides information about the optimum conditions to deliver genetic material to the cornea, and demonstrates for the first time the expression of meganuclease in human corneas ex vivo and its antiviral activity. In conclusion, we demonstrate that the treatment of human corneas in eye banks before transplantation is a new approach to address the unmet clinical needs in corneal diseases.
Collapse
|
20
|
Bucher F, Roters S, Mellein A, Hos D, Heindl LM, Cursiefen C, Hermann M. "OSMO-UT-DSAEK" using THIN-C medium. Graefes Arch Clin Exp Ophthalmol 2013; 251:2181-5. [PMID: 23907483 DOI: 10.1007/s00417-013-2434-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 06/24/2013] [Accepted: 07/16/2013] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND When performing ultra-thin Descemet's stripping automated endothelial keratoplasty (UT-DSAEK), the quality of the stromal interface and stromal thickness seem to be critical for visual outcome. The aim of this study was to investigate whether additional osmotic deswelling prior to UT-DSAEK improves the quality of the cut surface and leads to a more reliable and deeper cut in UT-DSAEK ("OSMO-UT-DSAEK"). METHODS Seventeen human donor corneas not usable for transplantation were used in this experiment. After standard deswelling with culture Medium II, ten corneas were randomly assigned to be additionally deswollen within THIN-C medium. The other remaining seven corneas were put back into culture Medium II. All corneas were placed in an artificial anterior chamber system (Moria); a double path cutting procedure using a microkeratome (Moria) was then performed. Corneal thickness was measured by ultrasound biomicroscopy and in paraffin-embedded slides, followed by histological grading of the cut surface. RESULTS Stromal interface smoothness significantly improved after preconditioning in THIN-C medium (Pearson P = 0.019). The correlation of the corneal thickness obtained by UBM (mean 706 ± SD 208 μm) and histology (mean 530 ± SD 159 μm) was not significant (Pearson r = 0.11, P > 0.05, mean difference 247, 95 % CI [+50;+304]). We found no significant correlation between the microkeratome setting and the actual thickness of the lenticule measured in histological analysis in both media as well as for the first and second cut (first cut: Pearson r = 0.9, P = 0.1, 95 % CI [-10;+96], second cut: Pearson r = 0.9, P = 0.4, 95 % CI [-10;+22]). CONCLUSION Preconditioning of corneas with THIN-C medium significantly improved the quality of the graft interface in UT-DSAEK, but did not significantly improve the cut precision of the microkeratome.
Collapse
Affiliation(s)
- F Bucher
- Department of Ophthalmology, University of Cologne, Kerpenerstraße 62, 50924, Cologne, Germany,
| | | | | | | | | | | | | |
Collapse
|
21
|
|
22
|
Kryczka T, Ehlers N, Nielsen K, Midelfart A. Impact of organ culturing on metabolic profile of human corneas: preliminary results. Acta Ophthalmol 2012; 90:761-7. [PMID: 21933358 DOI: 10.1111/j.1755-3768.2011.02213.x] [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: 11/30/2022]
Abstract
PURPOSE It is suggested that the quality of corneal graft may depend on modifications that appear in the tissue during culturing. The aim of this study was to investigate the differences in the metabolic profile between cultured and noncultured human corneas. METHODS Corneas from 12 donors were obtained post-mortem and cultured for 6-20 days. Control corneas were obtained from four patients with malignant melanoma of the chorioidea and were kept frozen at -80 °C until analysed. The metabolic profiles of the samples were investigated using high-resolution, magic angle spinning (1) H nuclear magnetic resonance spectroscopy and special software for: (i) analysis of complex mixtures, (ii) principal component analysis and (iii) specialized statistical analysis. RESULTS Twenty metabolites were detected and assigned in the corneas. Significant differences in metabolic profiles between cultured and noncultured corneas were revealed. It was also shown in samples kept in culture for 9-14 days that the levels of (i) alanine, formate, lactate and (ii) acetate, alanine, arginine, lactate were elevated in comparison with the samples kept for <9 and more than 14 days, respectively. CONCLUSIONS Corneal culturing affects the metabolic profile of the tissue. The increases in the levels of some metabolites within the second week of culturing likely result from variations in tissue metabolic or enzymatic activity caused by changed (organ culture) environment. As the mechanisms responsible for these changes are not clear, further research is indicated.
Collapse
Affiliation(s)
- Tomasz Kryczka
- Faculty of Medicine, Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, Norway.
| | | | | | | |
Collapse
|
23
|
Smith VA, Johnson TK. Identification and evaluation of a thinning agent compatible with MegaCell DCS, an animal product-free corneal storage medium. Graefes Arch Clin Exp Ophthalmol 2012; 250:1777-86. [PMID: 23011001 PMCID: PMC3501186 DOI: 10.1007/s00417-012-2126-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2012] [Revised: 06/13/2012] [Accepted: 07/24/2012] [Indexed: 11/30/2022] Open
Abstract
Purpose MegaCell DCS, an animal product-free culture medium formulated for storing corneas, is superior to the traditionally used MEM (Eagle’s) with Earles salts, Hepes, and supplemented with foetal calf serum (2 %), glutamine and an antibiotic cocktail (EB MEM). Because this medium does not prevent corneal swelling, and Dextran T500, which is traditionally used for reversing this process before transplant may have adverse effects on corneas, the purpose of the current investigation was to identify an alternative polymer that is compatible with MegaCell DCS. Methods Corneas maintained in MegaCell DCS or EB MEM were transferred to either EB MEM 5 % Dextran T500 or MegaCell DCS containing 5 % Dextran T500, 4 % polyethylene glycol (PEG) 10,000, PEG 35,000 (2 %, 3 %, 4 %) or Poloxamer 188 (4 %). Endothelial cell losses were determined and corneal hydration levels measured. Stromal cell cultures were generated and immunostained with anti α-SMA antibody. Janus Green was used to compare the viability of endothelial cells of corneas maintained in MegaCell DCS and EB MEM and respectively thinned with PEG 35,000 and Dextran T500. Results The rates of endothelial cell loss from corneas held in MegaCell DCS and thinned in MegaCell DCS containing 5 % Dextran T500, 4 % PEG 10,000 and 4 % Poloxamer 188 for 6 days were similar. When explants of these corneas were cultured myofibroblasts were generated. Although at concentrations of 4 % (w/v) both PEG 10,000 and Poloxamer 188 caused excessive dehydration, the hydration levels of corneas held in MegaCell DCS containing 3 % PEG 35,000 were similar to those of corneas held in EB MEM 5 % Dextran T500. Endothelial cell losses after 6 days were negligible, explants of the corneas generated uniform fibroblastic stromal cell cultures and the extents of Janus Green staining were similar. Over 20 days the inclusion of 5 % Dextran T500 in EB MEM but not 3 % PEG 35,000 in MegaCell DCS, increased the rate of endothelial cell loss. Conclusion PEG 35,000 at a concentration of 3 % w/v does not induce endothelial cell loss and is compatible with MegaCell DCS for thinning corneas prior to transplantation.
Collapse
Affiliation(s)
- Valerie A Smith
- Academic Unit of Ophthalmology, University of Bristol, Bristol Eye Hospital, Lower Maudlin Street, Bristol, BS1 2LX, UK.
| | | |
Collapse
|
24
|
Casadessus O, Georges G, Lamoine LS, Deumié C, Hoffart L. Light scattering from edematous human corneal grafts' microstructure: experimental study and electromagnetic modelization. BIOMEDICAL OPTICS EXPRESS 2012; 3:1793-1810. [PMID: 22876345 PMCID: PMC3409700 DOI: 10.1364/boe.3.001793] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Revised: 03/31/2012] [Accepted: 04/29/2012] [Indexed: 06/01/2023]
Abstract
Along with the lens, the cornea is the only transparent tissue in the human body. However, the development of an edema involves structural disturbances increasing light scattering and leading to the opacification of the cornea. Several mechanisms of transparency loss have been studied in the literature, but the whole phenomenon is complex and the part played by each scatterer is still unclear. We propose here to study human corneal grafts combining microscopic OCT imagery with far-field measurement of the scattered light in the reflected half-space. We introduce afterwards numerical calculations based on electromagnetic equations solved with first order approximation to link the observed microscopic-scale structural modifications with the intensity level of the scattered light, and to try and quantify the relationship between them.
Collapse
Affiliation(s)
- Olivier Casadessus
- Institut Fresnel, UMR CNRS 7249, Université d’Aix-Marseille, Ecole Centrale Marseille, Domaine universitaire de Saint Jérôme, Avenue Escadrille Normandie Niemen, 13 397 Marseille cedex 20, France
| | - Gaëlle Georges
- Institut Fresnel, UMR CNRS 7249, Université d’Aix-Marseille, Ecole Centrale Marseille, Domaine universitaire de Saint Jérôme, Avenue Escadrille Normandie Niemen, 13 397 Marseille cedex 20, France
| | - Laure Siozade Lamoine
- Institut Fresnel, UMR CNRS 7249, Université d’Aix-Marseille, Ecole Centrale Marseille, Domaine universitaire de Saint Jérôme, Avenue Escadrille Normandie Niemen, 13 397 Marseille cedex 20, France
| | - Carole Deumié
- Institut Fresnel, UMR CNRS 7249, Université d’Aix-Marseille, Ecole Centrale Marseille, Domaine universitaire de Saint Jérôme, Avenue Escadrille Normandie Niemen, 13 397 Marseille cedex 20, France
| | - Louis Hoffart
- Service d’Ophtalmologie de l’Hôpital de la Timone, APHM, Université d’Aix-Marseille, 264 rue Saint Pierre, 13 385 Marseille Cedex 5, France
| |
Collapse
|
25
|
Wolf A, von Jagow B, Kook D, Messmer EM, Lackerbauer CA, Kampik A, Kohnen T, Grueterich M. Evaluation of interface quality in organ-cultured lamellar corneal transplants. Clin Ophthalmol 2012; 6:967-72. [PMID: 22888202 PMCID: PMC3413341 DOI: 10.2147/opth.s30254] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND With increasing numbers of lamellar keratoplasties, eye banks are challenged to deliver precut lamellar donor tissue. In Europe, the most common technique of corneal storage is organ culture which requires a deswelling process before surgical processing. The aim of this study was to investigate the influence of different deswelling times on the cutting plane quality after microkeratome-assisted lamellar dissection. METHODS Eight paired donor corneas (16 specimens) not suitable for transplantation were organ cultured under standard conditions at the Eye Bank of the Ludwig-Maximilians Universität, Munich, Germany. Pairs of corneal buttons were analyzed during the deswelling process in dextrane-containing medium. While one cornea was cut at an early time point during the deswelling process and put back into deswelling medium thereafter, the partner cornea was completely deswollen and dissected after 72 hours. Specimens were then further processed for scanning electron microscopy. Surface quality was assessed both digitally using Scanning Probe Imaging Processing software, and manually by three blinded graders. RESULTS The corneal buttons processed at the beginning of the deswelling process had a smoother surface when compared to the partner cornea that was cut at the end of the deswelling process. In our setting, no relevant difference was detectable between manual and automated microkeratome dissection. CONCLUSION For lamellar keratoplasty, organ-cultured corneas should be processed at an early stage during the deswelling process. We interpret the smoother dissection plane during early deswelling as a result of mechanical properties in a highly hydrated cornea.
Collapse
Affiliation(s)
- Armin Wolf
- Department of Ophthalmology, Ludwig-Maximilians-Universität, München
| | - Burkhard von Jagow
- Department of Ophthalmology, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany
| | - Daniel Kook
- Department of Ophthalmology, Ludwig-Maximilians-Universität, München
| | | | | | - Anselm Kampik
- Department of Ophthalmology, Ludwig-Maximilians-Universität, München
| | - Thomas Kohnen
- Department of Ophthalmology, Johann Wolfgang Goethe-Universität, Frankfurt am Main, Germany
| | - Martin Grueterich
- Department of Ophthalmology, Ludwig-Maximilians-Universität, München
| |
Collapse
|
26
|
Peyrot DA, Aptel F, Crotti C, Deloison F, Lemaire S, Marciano T, Bancelin S, Alahyane F, Kowalczuk L, Savoldelli M, Legeais JM, Plamann K. Effect of incident light wavelength and corneal edema on light scattering and penetration: laboratory study of human corneas. J Refract Surg 2011; 26:786-95. [PMID: 20954687 DOI: 10.3928/1081597x-20100921-04] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE The outcome of ultrashort pulse laser surgery of the cornea is strongly influenced by the light scattering properties of the tissue, for which little data are available. The purpose of the present study is to provide quantitative values for light scattering and its relation to the degree of edema. METHODS An experimental optical measuring setup based on confocal geometry was used to measure the unscattered and scattered fractions of light transmitted by eye bank corneas presenting various degrees of edema. From these measurements, the effective light penetration depth in the cornea was calculated as a function of wavelength. RESULTS Corneal transparency depends on the pathological state of the cornea and on wavelength. It may be predicted as a function of corneal thickness, ie, the degree of edema. In healthy and edematous cornea, the percentage of scattered light decreases with increasing wavelength. The total penetration depths at the wavelengths of ~1050 nm (which is used in typical clinical systems) and 1650 nm (which is recommended for future devices) are comparable; however, the former is limited by scattering, which degrades the laser beam quality, whereas the latter is only limited by optical absorption, which may be compensated for. CONCLUSIONS The use of longer wavelengths should help improve the surgical outcome in ultrashort pulse laser surgery of the cornea when working on pathological tissue. A wavelength of approximately 1650 nm appears to be a good compromise, as it allows for reduced light scattering while keeping optical absorption reasonably low.
Collapse
Affiliation(s)
- Donald A Peyrot
- Laboratoire d'Optique Appliquée, ENSTA ParisTech-École Polytechnique, Palaiseau, France
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Grueterich M, Messmer EM, Lackerbauer C, Kampik A. Lamellar keratoplasty with a novel anterior chamber system and organ cultured donor corneas. Eur J Ophthalmol 2009; 20:276-82. [PMID: 19967666 DOI: 10.1177/112067211002000204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
PURPOSE To present a novel artificial anterior chamber system for anterior and posterior lamellar keratoplasty. METHODS The artificial anterior chamber system MOZARTTM in conjunction with the AMADEUSTM II microkeratome was evaluated for its applicability in anterior and posterior lamellar keratoplasty using organ cultured donor corneas. RESULTS Twelve patients underwent microkeratome-assisted lamellar keratoplasty for corneal opacifications due to either anterior stromal scaring or endothelial decompensation. Eight patients underwent Descemet stripping automated endothelial keratoplasty (DSAEK) and 4 patients underwent anterior lamellar keratoplasty (ALK). A 400-microm and 250-microm cutting head was used for DSAEK and ALK, respectively. In all patients, an 8.5-mm suction ring was applied. For the 250-microm cutting head, a mean anterior lamella thickness of 244+/-12 microm was found. For the 400-microm cutting head, a mean anterior lamella thickness of 390+/-18 microm was found. The graft diameter was 8.85+/-0.5 mm for the 8.5-mm suction ring with both cutting heads. Deswelling of the anterior donor lamella was 11.5% compared to 30% of the posterior lamella transplant after 6 months of follow-up. CONCLUSION The AMADEUSTM II microkeratome in conjunction with the MOZARTTM artificial anterior chamber system proved to be a suitable device for modern lamellar keratoplasty. Swelling and deswelling characteristics of organ cultured corneas need to be further investigated to optimize the deswelling time prior to donor cornea sectioning in lamellar keratoplasty.
Collapse
Affiliation(s)
- Martin Grueterich
- Department of Ophthalmology, Ludwig-Maximilians University, Munich, Germany.
| | | | | | | |
Collapse
|