Sammendrag
Abstract Objective: A population of stem cells (SCs) is responsible for maintenance and repair of the ocular surface. These stem cells can become deficient as a result of various diseases affecting the ocular surface. Depending on the extent of damage, the clinical features can vary from mild discomfort to substantial pain and/or blindness. The growing field of tissue engineering and advances in stem cell research offer promising new alternatives for these disorders. This student thesis will provide an overview of the human ocular surface (cornea, limbus, and conjunctiva), ocular surface stem cell deficiency, and treatment possibilities. Methods: This student thesis is based on a number of review articles and original articles on PubMed using the search words limbal, limbal stem cell deficiency, conjunctival and/or ocular surface reconstruction. Only papers written in English were considered. Findings: There are different possible methods for treating ocular surface stem cell deficiency by cultivating autologous and allogenic SCs using different kind of culture membranes. The most promising procedure for regenerating the ocular surface appears to be the transplantation of autologous cultivated epithelial sheets. Conjunctival tissue holds particular promise as it can be used both for treating corneal and conjunctival stem cell disorders. In most cases, it is possible to harvest a small piece of tissue from the patient s own eyes for further cultivation as, in contrast to corneal tissue, the conjunctiva is better protected (i.e. it also covers the back of the eyelids). By using autologous tissue, there is possible to avoid issues related to allografts, such as transmission of microorganisms, graft rejection, and long-term use of immune suppression. Identifying other autologous stem cell sources for patients with ocular surface stem cell deficiency is a major research focus, thus preventing the use of allogenic tissue for transplantation and avoiding the challenges this involves. There are still many challenges associated with cultured stem cell therapy, and many questions remain to be answered including how this therapy works and how the outcome can be best assessed clinically. Conclusion: Although several methods have proved useful for the regeneration of the ocular surface, strategies that include autologous tissue currently hold the greatest promise as these avoid the need for potentially lifelong immune suppression.