A Decrease in the Density of HLA-DR-Positive Cells Occurs Faster in Corneas Stored in Organ Culture than under Hypothermic Conditions
Laboratory of the Biology and Pathology of the Eye, Institute of Inherited Metabolic Disorders, Charles University in Prague, Czech Republic. Ophthalmic Research
(Impact Factor: 1.42).
06/2011; 47(1):39-46. DOI: 10.1159/000322801
To compare the number of antigen-presenting cells (APC) at various locations in fresh human corneoscleral disks and in those that are stored for grafting under hypothermic conditions or in organ culture (OC) with the aim of determining the conditions under which the decline in APC numbers is most substantial.
Cryosections obtained from fresh corneoscleral disks and disks stored under hypothermic (Optisol-GS) or OC conditions were used. The density of HLA-DR-positive cells was determined on cross sections using enzyme immunohistochemistry (alkaline phosphatase-antialkaline phosphatase technique). Longitudinal sections were used for detecting ATPase activity.
The densities of HLA-DR-positive cells in both the epithelium and stroma increased from the central (3.79 and 0.61/mm(2)) to the peripheral cornea (5.56 and 1.35/mm(2)) as well as to the limbus and conjunctiva. A marked decrease in the number of HLA-DR-positive cells occurred after 7 days of storage in all corneal areas, the limbus and conjunctiva, compared to fresh tissue. No positive cells were found in the epithelium of corneas after 14 days in OC and after 21 days in hypothermic storage. Twenty-eight days of storage in OC led to the complete absence of HLA-DR-positive cells in the epithelium of the limbus and conjunctiva, and to a significant reduction in the stroma.
Corneas stored in OC longer than 14 days are likely to be less immunogenic than corneas stored under hypothermic conditions, thus resulting in a possible positive effect on prolonging graft survival.
Available from: ncbi.nlm.nih.gov
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ABSTRACT: To determine the proliferative potential and the maintenance of stem cell activity in stored human limbal tissues, and correlate this with the preservation time, cell viability and the expression of stem cell markers.
Thirty limbal rims were split into 4 parts and stored in corneal preservation medium at 4°C for 0, 1, 4, or 7 days. The limbal stem cell and mitotic markers P63, CK19, proliferating cell nuclear antigen (PCNA), and Ki67 were determined by immunohistochemical staining. The proliferative potential of limbal epithelial cells was assessed by cell viability, the ability of generating stratified epithelium, and colony forming assay.
The stored tissues maintained limbal stratified structure to 7 days and exhibited comparable expression level of stem cell and mitotic markers. The proportion of viable cells decreased with the prolonged preservation time, while colony forming efficiency decreased from the 1(st) day and disappeared at the 4(th) day. When inoculated on amniotic membrane, the cells preserved for 1 day formed a stratified epithelium, while the cells from 4 days' preservation formed a discontinuous layer.
The colony forming efficiency of limbal epithelial stem/progenitor cells decreased rapidly with the increasing preservation time, while the expression level of markers and capacity of forming epithelial monolayer on amniotic membrane decreased gradually. The limbal epithelial stem cells lost their function earlier than the lost expression level of stem cell markers. This may help us to better choose the appropriate preservation grafts for future limbal stem cell transplantation.
10/2012; 5(5):549-54. DOI:10.3980/j.issn.2222-3959.2012.05.02
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To assess the impact of autologous serum (AS) eye drops on the ocular surface of patients with bilateral severe dry eye and to draw a comparison between the clinical and laboratory examinations and the degree of subjective symptoms before and after serum treatment.
Materials and methods:
A three-month prospective study was conducted on 17 patients with severe dry eye. AS eye drops were applied a maximum of 12 times a day together with regular therapy. Dry eye status was evaluated by clinical examination (visual acuity, Schirmer test, tear film breakup time, vital staining, tear film debris and meniscus), conjunctival impression cytology (epithelial and goblet cell density, snake-like chromatin, HLA-DR-positive and apoptotic cells) and subjectively by the patients.
The application of AS eye drops led to a significant improvement in the Schirmer test (p < 0.01) and tear film debris (p < 0.05). The densities of goblet (p < 0.0001) and epithelial cells (p < 0.05) were significantly increased, indicating a decrease of squamous metaplasia after AS treatment. A significant decrease (p < 0.05) was found in the number of apoptotic, HLA-DR-positive and snake-like chromatin cells on the ocular surface. A significant improvement was found in all evaluated subjective symptoms. Altogether, the clinical results were improved in 77%, the laboratory results in 75% and the subjective feelings in 63% of the eyes.
We found that three-month AS treatment led especially to the improvement of ocular surface dryness and damage of the epithelium. The improvement of dry eye after AS treatment correlated well with the clinical, laboratory and subjective findings. From the patients' subjective point of view, the positive effect of AS decreased with time, but still persisted up to three months after the end of therapy.
Current eye research 09/2013; 39(1). DOI:10.3109/02713683.2013.824987 · 1.64 Impact Factor
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ABSTRACT: The benefit of matching the donor and recipient of corneal allografts for Human Leukocyte Antigens (HLA) has often been debated. Currently, patients receiving their first corneal allograft are hardly ever matched for HLA antigens and even patients undergoing a regraft usually do not receive an HLA-matched graft. The great success of primary corneal transplantations is based on the ocular immune privilege. Although this indeed seems to render HLA-matching superfluous, in vascularized recipients, immune privilege is more often compromised than not, which leads to an increased risk of graft rejection. This review presents an overview of the background, alternatives, and current opinions on the relevance of HLA matching in corneal transplantation, and shows that current data support the benefit of matching for HLA Class I and II antigens in high risk corneal transplantations.
Copyright © 2015. Published by Elsevier Ltd.
Progress in Retinal and Eye Research 01/2015; 46. DOI:10.1016/j.preteyeres.2015.01.001 · 8.73 Impact Factor
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