Identification of factors regulating differentiation and growth of limbal stem cells for corneal surface regeneration

2012 ◽  
Vol 90 ◽  
pp. 0-0 ◽  
Author(s):  
V HOLAN ◽  
P TROSAN ◽  
M KRULOVA ◽  
A ZAJICOVA
2009 ◽  
Vol 03 (02) ◽  
pp. 82
Author(s):  
Sophie X Deng ◽  

The ocular surface is covered by non-keratinised stratified epithelial cells that provide the first line of defence against external insults. Under normal conditions, the superficial layer of the corneal epithelium undergoes constant desquamation and is maintained by the basal layer through the regenerative process of self-renewal. This regeneration capacity depends on the corneal epithelial stem cells that are believed to reside at the basal layer of the limbal epithelium and hence are called limbal stem cells (LSCs). Deficiency of LSCs seen in many ocular diseases leads to the loss of vision as a result of invasion of the conjunctival epithelium and neovascularisation of the corneal surface. In this article, the aetiology, clinical presentation, diagnosis and current management of LSC deficiency are discussed, with an emphasis on new tissueengineering techniques to expand and regenerate LSCs for transplantation.


Small ◽  
2021 ◽  
Vol 17 (10) ◽  
pp. 2003937
Author(s):  
Irene Anton‐Sales ◽  
Laura Koivusalo ◽  
Heli Skottman ◽  
Anna Laromaine ◽  
Anna Roig

2001 ◽  
Vol 72 (9) ◽  
pp. 1478-1485 ◽  
Author(s):  
Paolo Rama ◽  
Stefano Bonini ◽  
Alessandro Lambiase ◽  
Osvaldo Golisano ◽  
Patrizia Paterna ◽  
...  

2001 ◽  
Vol 21 (4) ◽  
pp. 385-405 ◽  
Author(s):  
Virender S. Sangwan

Stem cells are present in all self-reviewing tissues and have unique properties. The ocular surface is made up of two distinct types of epithelial cells, constituting the conjunctival and the corneal epithelia. These epithelia are stratified, squamous and non-keratinized. Although anatomically continuous with each other at the corneoscleral limbus, the two cell phenotypes represent quite distinct subpopulations. The stem cells for the cornea are located at the limbus. The microenvironment of the limbus is considered to be important in maintaining stemness of the stem cells. They also act as a “barrier” to conjunctival epithelial cells and prevent them from migrating on to the corneal surface. In certain pathologic conditions, however, the limbal stem cells may be destroyed partially or completely resulting in varying degrees of stem cell deficiency with its characteristic clinical features. These include “conjunctivalization” of the cornea with vascularization, appearance of goblet cells, and an irregular and unstable epithelium. The stem cell deficiency can be managed with auto or allotransplantation of these cells. With the latter option, systemic immunosuppression is required. The stem cells can be expanded ex vivo on a processed human amniotic membrane and transplanted back to ocular surface with stem cell deficiency without the need of immunosuppression.


Medicina ◽  
2021 ◽  
Vol 57 (4) ◽  
pp. 369
Author(s):  
Sang Beom Han ◽  
Farah Nur Ilyana Mohd Ibrahim ◽  
Yu-Chi Liu ◽  
Jodhbir S. Mehta

Background and objectives: the aim of this study was to analyze the efficacy of a modified “amnion-assisted conjunctival epithelial redirection (ACER)” technique for the treatment of partial limbal stem cell deficiency (LSCD). Materials and methods: the medical records of three patients with partial LSCD who underwent corneal surface reconstruction with modified ACER following superficial keratectomy were retrospectively studied. Briefly, in this technique, an inner amniotic membrane (AM) layer was applied on the corneal surface to promote corneal re-epithelialization. The outer AM layer was applied as a barrier to prevent the invasion of conjunctival epithelial cells into the cornea before the corneal surface was completely covered by corneal epithelial cells derived from the remaining intact limbal stem cells. Results: in all three cases, the outer AM layer successfully kept the conjunctival epithelium away from the corneal surface and prevented an admixture of conjunctival epithelial cells with corneal epithelial cells. In all three patients, the cornea was completely re-epithelized with epithelial cells derived from the remaining healthy limbal stem cells, and a clear visual axis was maintained without recurrence for a mean follow-up period of 37.3 ± 8.6 months. Conclusions: the preliminary results suggest that modified ACER appears to be a viable option for patients with partial LSCD.


2006 ◽  
Vol 69 (12) ◽  
pp. 983-991 ◽  
Author(s):  
Enzo Di Iorio ◽  
Vanessa Barbaro ◽  
Stefano Ferrari ◽  
Claudio Ortolani ◽  
Michele De Luca ◽  
...  

2019 ◽  
Vol 8 (2) ◽  
pp. 41
Author(s):  
Zarka Stoycheva ◽  
Yana Manolova ◽  
Yordan Yordanov

2017 ◽  
Vol 86 (7-8) ◽  
Author(s):  
Petra Schollmayer ◽  
Zala Lužnik

Background: Corneal epithelium is renewed by stem cells (SC) that reside at the corneal limbus. Reduced number of SC or their abnormal function lead to the ocular surface disease called limbal stem cell deficiency (LSCD), characterized by corneal conjunctivalization, vascularization, persistent epithelial defects, chronic inflammation, and loss of vision. In a case of total unilateral LSCD, autologous transplantation of limbal epithelial stem cells (LESC) from the healthy eye is needed. We describe the surgical technique of choice for autologous limbal transplantation, called conjunctival limbal autograft (CLAU) that we combined with amniotic membrane (AM) use. We present the results of CLAU in three patients with total unilateral LSCD due to chemical injury.Methods: Autologous limbal transplantation CLAU begins with the removal of fibrovascular pannus from the diseased corneal surface and the harvesting of two conjunctival-limbal grafts from the healthy eye. The grafts are then transplanted on to the limbal area of the recipient eye. AM is used as a patch to cover the denuded cornea and limbal grafts, as well as a barrier preventing the conjunctival epithelium from encroaching on to the temporal and nasal side of the corneal surface. In the donor eye, AM is used to cover the donor sites. CLAU with the use of AM was performed in 3 patients with unilateral LSCD due to chemical eye injury. In one patient limbal transplantation was combined with symblepharon lysis for entropium repair. In all cases AM was removed 3–6 days postoperatively to assess the growth of new epithelium from the limbal grafts. In all patients the ocular surface was covered with another AM until the cornea was completely epithelized and the new epithelium stable. In one patient the corneal regrafting and cataract removal was performed subsequently.Results: CLAU was successful in 2 patients and partially successful in 1 patient during the follow up. In all cases the growth of new epithelium from the limbal grafts was noted on day 3–6 after CLAU. The cornea was completely epithelized within 2 weeks in 2 patients and after 35 days in one patient. In two patients the corneal epithelium remained clear, smooth and stable during the follow up of 3.5 years and 4 months, respectively. In one patient, uneven epithelium probably representing a mosaic of corneal and conjunctival cells was noted in the central corneal region, where a small corneal ulcer developed 5 months after CLAU. In donor eyes no postoperative complications were noted, the donor sites epithelized within few days.Conclusions: Autologous limbal transplantation according to CLAU surgical technique combined with the use of AM is a successful and safe therapy for restoring corneal surface in total unilateral LSCD after chemical injury. It enables further surgical procedures for restoring the vision such as corneal transplantation and cataract surgery.


2016 ◽  
Vol 5 (83) ◽  
pp. 6182-6185
Author(s):  
Subbiah Vasan Chandrakumar ◽  
Sudalaiyandi Ganapathirajesh ◽  
Shanmugasami Kavitha ◽  
Sundararajalu Abirami ◽  
Mohanasundaram Vijayalakshmi ◽  
...  

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