BACKGROUND Limbal epithelial stem cells (LESCs) have been localized to the palisades of Vogt and serve as a source for continuous renewal of the corneal epithelium. LESCs can be destroyed as a result of tumours or autoimmune, traumatic, congenital, infectious or iatrogenic causes, which all lead to limbal stem cell deficiency (LSCD). The results are neovascularisation, chronic inflammation as well as opacification of the cornea with symptoms of discomfort, pain, photophobia, and severely reduced vision. The most widely accepted treatment of LSCD with corneal opacification is corneal transplantation in conjunction with cultured limbal epithelium transplantation (CLET). Novel stromal substitutes together with optimized CLET procedures hold great promise for the treatment of this clinically challenging disease modality. Transplantation of LESCs is, however, hampered by the fragility of the epithelium and a cell carrier is therefore required. Several different carrier solutions have been investigated, including amniotic membrane, which is currently the golden standard, collagen scaffolds, and siloxane hydrogel contact lenses, all with varying results.
AIM The aim of this project was to investigate and compare cell adhesion, proliferation and maintenance of stem cell potential of stem cells on natural and synthetic substrates that would support differentiation towards corneal phenotype in a serum- and feeder-free system.
METHODS In this project, growth and morphology of stem cells on intact amniotic membrane, epithelially denuded amniotic membrane, acellular amniotic membrane, plastic compressed collagen membrane, CCC and PIPAA culture dishes was evaluated on adipose-derived stem cells (ASCs) as a model for LESCs. In addition, limbal epithelial cells (LECs) were isolated from corneoscleral rims with either Dispase or collagenase and grown in a xeno- and feeder-free system.
RESULTS ASCs were capable of attaching to all of the tested substrates within 24 hours of seeding. ASCs on dAM and aAM displayed the largest proliferation rate (p < 0,05), while there was no significant difference between the other substrates and controls after three days of culturing. Furthermore, greater numbers of LECs could be isolated from corneoscleral rings with collagenase than with Dispase, however viability of donor tissue posed some problems.
CONCLUSION Results from ASCs as a model for stem cell growth on substrates suggests its importance in regulation specific cell features, such as morphology and proliferation. Viability of donor tissue, however, posed a problem and LECs could not be grown on the substrates. It is therefore important to conduct more research on this subject.