ABSTRACT.Purpose: To investigate the ability of mesenchymal stem cells (MSC) to transdifferentiate to corneal epithelial cells in experimental limbal stem cell deficiency in rabbits. Methods: Total limbal stem cell deficiency was produced in 21 right eyes of 21 New Zealand rabbits; 6 eyes served as controls (group 1, G1). After removal of the conjunctival overgrowth, five eyes received amniotic membrane transplantation (AMT; G2). In four eyes, autologous limbal stem cell transplantation from the healthy eye was performed with AMT (G3). In another six eyes, enriched autologous MSC were injected under the amniotic membrane (AM) (G4). Within 280 days, corneoscleral discs were analysed for goblet cells, cytokeratin (CK) 3 ⁄ 12, connexin 43, b 1 -integrin, CK 19, a-enolase, p63 and ATP-binding cassette transporter subtype G-2 (ABCG-2) distribution patterns. Results: Cultivated MSC were positive for CK 3 ⁄ 12 and a-enolase, but negative for ABCG-2, p63 and connexin 43. On rabbit corneas, CK 3 ⁄ 12 was expressed in all corneal regions in all groups, but with significantly different intensities. Among all other parameters, expression levels of ABCG-2, b 1 -integrin and connexin 43 were significantly different between the transplanted groups and the control group. After a mean follow-up time of 172 (47-280) days, goblet cells were rarely present in the central cornea (G1-4). Conclusion: CK 3 ⁄ 12 is not highly specific for differentiated corneal epithelium. Further, goblet cells are not a reliable marker for conjunctivalization in rabbits. Expression of ABCG-2, b 1 -integrin and connexin 43 after mesenchymal stem cell transplantation may indicate their ability to maintain their stem cell character or to transdifferentiate to epithelial progenitor cells.

Implantation of the black diaphragm aniridia IOL improved visual acuity in the majority of patients with a variety of endogenous problems in addition to aniridia.

Background/aim: Advanced donor age, long death to excision time interval, and factors related to organ culture can trigger unfavourable intracellular processes in the graft endothelium and contribute to chronic endothelial cell loss after penetrating keratoplasty. The aim of this study was to investigate factors influencing chronic endothelial cell loss in a homogeneous group of patients. Methods: 177 patients after first normal risk keratoplasties for keratoconus were retrospectively selected from the quality control database of our clinic. For 71 of them at least four central endothelial cell density values were documented in follow up. From these patients, only those 53 without any further intraocular procedures, without glaucoma, and without graft rejection were considered. A scatter plot of logarithmised endothelial cell density values against postoperative time was drawn for each patient. The slope of the regression line then equals the constant of decay in central endothelial cell density. The influence of donor age and storage time in organ culture on this index value of cell loss was investigated by means of linear regression analysis. Results: Mean loss of central endothelial cell density was 16.7% per year. Regression analysis revealed a statistically significant negative linear effect of both postmortem time (β = -0.324; p = 0.014) and donor age (β = -0.282; p = 0.036) and a trend for storage time in organ culture (β = -0.195; p = 0.142) in a combined linear regression model. Conclusion: Increased postmortem time and advanced donor age exert a significant negative effect on chronic endothelial cell loss. Storage time in organ culture seems to be third influencing factor. These negative influences may be reduced by compensating advanced donor age with minimised postmortem and storage time.

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Background: With the use of systemic cyclosporin A (CsA), graft prognosis after high-risk penetrating keratoplasty has improved considerably. However, the application of CsA is limited owing to a variety of severe side effects. In this prospectively randomized study mycophenolate mofetil (MMF), a safe and efficient immunosuppressive medication after renal transplantation, was compared with CsA after high-risk penetrating keratoplasty. Methods: Twenty-nine high-risk keratoplasty patients were treated with MMF 2× 1 g daily; another 27 patients received CsA, aiming at blood trough levels of 120-150 ng/ml. Systemic immunosuppression was scheduled for 6 months. In both groups oral corticosteroids (fluocortolone 1 mg/kg) were administered for 3 weeks postoperatively. Results: During the first year after operation, no graft failure was recorded. Two years postoperatively 92%/82% and 3 years postoperatively 74%/69% of grafts were clear in the MMF and CsA group, respectively (Kaplan Meier P=0.33, logrank test). In total, two graft failures were recorded in the MMF group and four in the CsA group. Three years postoperatively 53% of the Graefe's Arch Clin Exp Ophthalmol