Use of glycerol-preserved corneas for corneal transplants.
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ABSTRACT:
SUBMITTER: Gupta N
PROVIDER: S-EPMC5549407 | biostudies-other | 2017 Jul
REPOSITORIES: biostudies-other
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Project description:BackgroundIndividuals who have failed one or more full thickness penetrating keratoplasties may be offered repeat corneal surgery using an artificial or donor cornea. An artificial or prosthetic cornea is known as a keratoprosthesis. Both donor and artificial corneal transplantations involve removal of the diseased and opaque recipient cornea (or the previously failed cornea) and replacement with another donor or prosthetic cornea.ObjectivesTo assess the effectiveness of artificial versus donor corneas in individuals who have had one or more failed donor corneal transplantations.Search methodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2019, Issue 11); Ovid MEDLINE; Ovid Embase; LILACS (Latin American and Caribbean Health Sciences Literature database); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 4 November 2019.Selection criteriaTwo review authors independently assessed reports from the electronic searches to identify randomized controlled trials or controlled clinical trials. Any discrepancies were resolved by discussion or consultation.Data collection and analysisWe used standard methodological procedures expected by Cochrane. For discussion purposes, we summarized findings from relevant comparative case series. We performed no data synthesis.Main resultsWe did not identify any randomized controlled trials or controlled clinical trials comparing artificial corneas with donor corneas for repeat corneal transplantations.Authors' conclusionsThe optimal management for those individuals who have failed a conventional corneal transplantation is unknown. Currently, in some centers, artificial corneal devices are routinely recommended after just one graft failure, while in other centers, they are not recommended until after multiple graft failures, or not at all. To date, there have been no controlled trials comparing the visual outcomes and complications of artificial corneal devices (particularly the Boston type 1 keratoprosthesis, which is the most commonly implanted artificial corneal device) with repeat donor corneal transplantation, in order to guide surgeons and their patients. Such a trial is needed and would offer significant benefit to an ever-increasing pool of people with visual disability due to corneal opacification, most of whom are still in productive stages of their lives.
| S-EPMC7388900 | biostudies-literature
Project description:Background and objectives: This report describes an unusual presentation of severe hypertension (HTN) in a subset of pediatric kidney recipients treated with a steroid avoidance pediatric renal transplantation protocol. The HTN was secondary to atypical, reno-vascular abnormalities (RVA) of the transplanted vasculature, temporally associated with erythropoietin (EPO) use. Design, setting, participants, and measurements: To investigate the clinical significance underlying this event, a retrospective clinical study of 100 pediatric renal transplants was undertaken (50 steroid-free and 50 matched steroid-based controls), with peripheral blood transcriptional analysis of four RVA patients and controls. Results: Regardless of a higher observed incidence of anemia (p < 0.001) and greater overall EPO usage in the first post-transplant year in steroid-free patients, the incidence of new-onset HTN at one yr was significantly less in the steroid-free cohort (p = 0.03). Nevertheless, early EPO (first week post-transplant) was significantly associated with the combinatory findings of new-onset HTN (p = 0.03) and RVA (p = 0.007). Molecular mechanisms of RVA injury were investigated further by peripheral blood cDNA microarray gene expression profiling. A panel of 42 transcripts differentiated patients with RVA and HTN from three sets of matched controls, with and without HTN and EPO use, with 100% concordance (p < 0.001). The biological processes governed by these significant genes suggest a role for EPO regulation of growth factor receptor ubiquitination as a putative mechanism for renal vascular injury. Conclusion: This study cautions against the use early post-transplant use of EPO in immunosuppression regimens with steroid minimization/avoidance, which may have an increased incidence of post-transplant anemia. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Disease State: patient with high blood pressure Keywords: Logical Set Using regression correlation
2008-10-21 | E-GEOD-13198 | biostudies-arrayexpress
Project description:Background and objectives: This report describes an unusual presentation of severe hypertension (HTN) in a subset of pediatric kidney recipients treated with a steroid avoidance pediatric renal transplantation protocol. The HTN was secondary to atypical, reno-vascular abnormalities (RVA) of the transplanted vasculature, temporally associated with erythropoietin (EPO) use. Design, setting, participants, and measurements: To investigate the clinical significance underlying this event, a retrospective clinical study of 100 pediatric renal transplants was undertaken (50 steroid-free and 50 matched steroid-based controls), with peripheral blood transcriptional analysis of four RVA patients and controls. Results: Regardless of a higher observed incidence of anemia (p < 0.001) and greater overall EPO usage in the first post-transplant year in steroid-free patients, the incidence of new-onset HTN at one yr was significantly less in the steroid-free cohort (p = 0.03). Nevertheless, early EPO (first week post-transplant) was significantly associated with the combinatory findings of new-onset HTN (p = 0.03) and RVA (p = 0.007). Molecular mechanisms of RVA injury were investigated further by peripheral blood cDNA microarray gene expression profiling. A panel of 42 transcripts differentiated patients with RVA and HTN from three sets of matched controls, with and without HTN and EPO use, with 100% concordance (p < 0.001). The biological processes governed by these significant genes suggest a role for EPO regulation of growth factor receptor ubiquitination as a putative mechanism for renal vascular injury. Conclusion: This study cautions against the use early post-transplant use of EPO in immunosuppression regimens with steroid minimization/avoidance, which may have an increased incidence of post-transplant anemia. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Disease State: patient with high blood pressure Keywords: Logical Set
2008-10-21 | GSE13198 | GEO
Project description:PurposeTo characterize the corneal epithelium (CE) and limbal epithelium (LE) of human corneas stored in an innovative active storage machine (ASM) after a period of organ culture (OC).MethodsCorneas unsuitable for graft and stored in a standard commercial OC medium for 2 to 5 weeks were transferred into our ASM for 14 days. The ASM actively maintained an overpressure on the endothelial side (20 mm Hg) while ensuring medium renewal. We compared three modalities of storage in the ASM's epithelial chamber: (1) alternating exposure to a supplemental hormonal epithelial medium (SHEM) and air (air-lifting), (2) continuous immersion in SHEM, and (3) continuous immersion in OC medium. Passive immersion of the whole cornea in OC medium or of the CE in SHEM with or without airlifting served as controls. Paired corneas were used for better comparability. Histology, differentiation (by immunolabeling), and ultrastructure were analyzed at the end.ResultsThe ASM with air-lifting was most effective in regenerating a pluristratified and differentiated CE (apical ZO-1 and MUC16 staining and regeneration of the glycocalyx). In addition, the LE was stratified with preserved expression of ABCB5. The ASM with immersion in SHEM or OC medium gave a less stratified and differentiated CE. In the three control groups, the epithelia, when present, were paucistratified and less differentiated.ConclusionsIn human corneas previously stored in OC, the ASM regenerates a CE with differentiation characteristics close to normal.Translational relevanceRegeneration of the epithelium of human corneas discarded by eye banks will increase tissue availability for research.
| S-EPMC7900847 | biostudies-literature
Project description:Corneal transplantation remains the last hope for vision restoration, and lymphangiogenesis (LG) is a primary mediator of transplant rejection. This study was to investigate the specific role of angiopoietin-2 (Ang-2) in transplantation-associated LG and graft rejection.Orthotopic corneal transplantation was performed between fully mismatched C57BL/6 (donor) and BALB/c (recipient) mice to assess the effects of Ang-2 blockade via neutralizing antibody. Grafts were evaluated in vivo by ophthalmic slit-lamp biomicroscopy and anterior segment optical coherence tomography (OCT) up to 8 weeks after surgery. Additionally, whole-mount corneas were analyzed for lymphatic and blood vessels and macrophages by immunofluorescent microscopy, and draining lymph nodes were assessed for donor-derived cells by flow cytometry.Anti-Ang-2 treatment significantly suppressed LG and graft rejection. In this study, we achieved 75% suppression of LG and 80% graft survival. Our approach also inhibited donor-derived cell trafficking to draining lymph nodes and affected macrophage morphologic phenotypes in the grafted corneas. Additionally, Ang-2 blockade also reduced central corneal thickening, a parameter strongly associated with graft rejection.Ang-2 is critically involved in corneal transplant rejection and anti-Ang-2 treatment significantly improves the outcomes of corneal grafts. Moreover, we have shown that anterior segment OCT offers a new tool to monitor murine corneal grafts in vivo. This study not only reveals new mechanisms for transplant rejection, but also offers a novel strategy to treat it.
| S-EPMC5231909 | biostudies-other
Project description:ObjectiveTo validate a new method for reconstructing corneal biomechanical properties from air puff corneal deformation images using hydrogel polymer model corneas and porcine corneas.MethodsAir puff deformation imaging was performed on model eyes with artificial corneas made out of three different hydrogel materials with three different thicknesses and on porcine eyes, at constant intraocular pressure of 15 mmHg. The cornea air puff deformation was modeled using finite elements, and hyperelastic material parameters were determined through inverse modeling, minimizing the difference between the simulated and the measured central deformation amplitude and central-peripheral deformation ratio parameters. Uniaxial tensile tests were performed on the model cornea materials as well as on corneal strips, and the results were compared to stress-strain simulations assuming the reconstructed material parameters.ResultsThe measured and simulated spatial and temporal profiles of the air puff deformation tests were in good agreement (< 7% average discrepancy). The simulated stress-strain curves of the studied hydrogel corneal materials fitted well the experimental stress-strain curves from uniaxial extensiometry, particularly in the 0-0.4 range. Equivalent Young´s moduli of the reconstructed material properties from air-puff were 0.31, 0.58 and 0.48 MPa for the three polymer materials respectively which differed < 1% from those obtained from extensiometry. The simulations of the same material but different thickness resulted in similar reconstructed material properties. The air-puff reconstructed average equivalent Young´s modulus of the porcine corneas was 1.3 MPa, within 18% of that obtained from extensiometry.ConclusionsAir puff corneal deformation imaging with inverse finite element modeling can retrieve material properties of model hydrogel polymer corneas and real corneas, which are in good correspondence with those obtained from uniaxial extensiometry, suggesting that this is a promising technique to retrieve quantitative corneal biomechanical properties.
| S-EPMC5085055 | biostudies-literature
Project description:Eye banked research-grade human donor corneas serve as principal ex vivo source for studying the mechanisms that underlie corneal endothelial cell damage/death and survival. Wide-field specular microscopy can be used for corneal endothelial visualization and allows for indirect assessment of endothelial cell function by analyzing endothelial cell density and morphometric parameters. However, a standardized approach is needed to observe corneal endothelial changes over time. This protocol describes reliable ex vivo methods for consecutive analyses of human donor corneal endothelial cell density and morphometric parameters change using a wide-field dual imaging specular microscope. This protocol involves tissue warming, acquisition and analysis of specular endothelial images, assessment of corneal layers with the new Enhance mode, optical pachymetry measurement, and qualitative image quality grading scales. This quantitative and qualitative evaluation of donor corneas allows for a systematic analysis of endothelial dynamic responses to ex vivo induced stress and can be used as a valuable tool to better elucidate specular findings and mechanisms mediating corneal endothelial cell loss in corneal disease and after transplantation.
| S-EPMC6888603 | biostudies-literature
Project description:PURPOSE:To determine the feasibility of using telemedicine consultations in the evaluation of recovered donor corneas for transplant suitability. METHODS:This study aims to establish and test the minimum imaging requirements for telemedical consultations of corneal tissue by remote eye bank medical directors. Digital images from the slit lamp, optical coherence tomography, and/or specular microscope were assembled into telemedical consults and emailed to 4 eye bank medical directors (M.A.T., J.W., C.S.S., N.K.R.). Feedback on the minimum image requirements for each corneal finding was collected. After establishing a standardized imaging and presentation protocol, test cases were presented to the medical directors to examine the validity of these remote consults. To establish a benchmark for the study's parameters, one medical director (J.W.) examined each case in person after his initial remote review. Examiners were masked to each other's responses. RESULTS:Minimum image requirements for determination of corneal findings were defined and were specific to each anatomic layer of the cornea (epithelial, stromal, or endothelial). Using a defined set of digital images for a set of common corneal findings, the rate of agreement between remote evaluators, eye bank staff, and the in-person evaluator was 100% (11 of 11 examples). For ambiguous test cases, remote evaluators agreed on 80% of the cases (4 of 5). CONCLUSIONS:Results from this pilot study suggest that telemedical review of corneal tissue using high-quality digital images may be adequate for accurate identification of specific corneal findings commonly encountered by eye banks.
| S-EPMC6403003 | biostudies-literature
Project description:AIMS: To report the surgical outcome of tectonic graft using glycerol-preserved donor corneas to treat perforated keratitis. METHODS: The medical records were reviewed of all patients treated for perforated keratitis using glycerol-preserved corneas at a single institution between 1 July 2004 and 31 June 2010. The clinical features, precipitating factors, adjuvant therapies, and therapeutic outcomes were analyzed. Success was defined as re-epithelialization of the ocular surface without evisceration. RESULTS: Fourteen eyes from 14 patients (6 male and 8 female) were included. Age ranged from 58 to 84 years (average, 70.71 ± 8.52 years) and the follow-up time ranged from 7 to 56 months (mean, 25.35 ± 16.84 months). The culture results showed five bacterial infections, five cases of fungal keratitis, and one mixed infection; the culture results were negative for three patients. Satisfactory anatomical integrity was obtained in eight grafts (57.14%) that healed with neovascularization. Six grafts (48.85%) showed delayed re-epithelialization and were repaired with conjunctival flaps to maintain ocular surface integrity. Three patients developed secondary glaucoma and received trans-scleral cyclophotocoagulation. Thirteen patients had satisfactory anatomical integrity without evisceration or exenteration, while one patient received evisceration at 39-month follow-up because of intractable glaucoma. CONCLUSIONS: Glycerol-preserved donor corneas combined with anterior vitrectomy with or without conjunctival flaps may be effective substitutes for evisceration surgery in patients with perforated keratitis.
| S-EPMC3496105 | biostudies-other
Project description:Dissection of host-pathogen interactions is important for both understanding the pathogenesis of infectious diseases and developing therapeutics for the infectious diseases like various infectious keratitis. To enhance the knowledge about pathogenesis infectious keratitis, a random 12-mer peptide phage display library was screened against cultured human corneal epithelial cells (HCEC). Fourteen sequences were obtained and BLASTp analysis showed that most of their homologue counterparts in GenBank were for defined or putative proteins in various pathogens. Based on known or predicted functions of the homologue proteins, ten synthetic peptides (Pc-A to Pc-J) were measured for their affinity to bind cells and their potential efficacy to interfere with pathogen adhesion to the cells. Besides binding to HCEC, most of them also bound to human corneal stromal cells and umbilical endothelial cells to different extents. When added to HCEC culture, the peptides induced expression of MyD88 and IL-17 in HCEC, and the stimulated cell culture medium showed fungicidal potency to various extents. While peptides Pc-C and Pc-E inhibited Aspergillus fumigatus (A.f) adhesion to HCEC in a dose-dependent manner, the similar inhibition ability of peptides Pc-A and Pc-B required presence of their homologue ligand Alb1p on A.f. When utilized in an eyeball organ culture model and an in vivo A.f keratitis model established in mouse, Pc-C and Pc-E inhibited fungal adhesion to corneas, hence decreased corneal disruption caused by inflammatory infiltration. Affinity pull-down of HCEC membrane proteins with peptide Pc-C revealed several molecules as potential receptors for this peptide. In conclusion, besides proving that phage display-selected peptides could be utilized to interfere with adhesion of pathogens to host cells, hence could be exploited for managing infectious diseases including infectious keratitis, we also proposed that the phage display technique and the resultant peptides could be used to explore host-pathogen interactions at molecular levels.
| S-EPMC3299800 | biostudies-literature