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Limbal Stem Cells (limbal + stem_cell)
Selected AbstractsHuman immature dental pulp stem cells share key characteristic features with limbal stem cellsCELL PROLIFERATION, Issue 5 2009B. G. Monteiro Objectives:, Limbal stem cells (LSC) are self-renewing, highly proliferative cells in vitro, which express a set of specific markers and in vivo have the capacity to reconstruct the entire corneal epithelium in cases of ocular surface injury. Currently, LSC transplantation is a commonly used procedure in patients with either uni- or bilateral total limbal stem cells deficiency (TLSCD). Although LSC transplantation holds great promise for patients, several problems need to be overcome. In order to find an alternative source of cells that can partially substitute LSC in cornea epithelium reconstruction, we aimed at investigating whether human immature dental pulp stem cells (hIDPSC) would present similar key characteristics as LSC and whether they could be used for corneal surface reconstruction in a rabbit TLSCD model. Materials:, We used hIDPSC, which co-express mesenchymal and embryonic stem cell markers and present the capacity to differentiate into derivative cells of the three germinal layers. TLSCD was induced by chemical burn in one eye of rabbits. After 30 days, the opaque tissue formed was removed by superficial keratectomy. Experimental group received undifferentiated hIDPSC, while control group only received amniotic membrane (AM). Both groups were sacrificed after 3 months. Results and conclusions:, We have demonstrated, using immunohistochemistry and reverse transcription,polymerase chain reaction, that hIDPSCs express markers in common with LSC, such as ABCG2, integrin ,1, vimentin, p63, connexin 43 and cytokeratins 3/12. They were also capable of reconstructing the eye surface after induction of unilateral TLSCD in rabbits, as shown by morphological and immunohistochemical analysis using human-specific antibodies against limbal and corneal epithelium. Our data suggest that hIDPSCs share similar characteristics with LSC and might be used as a potential alternative source of cells for corneal reconstruction. [source] 2332: Pathological changes of anatomical structure and markers of limbal stem cell niche due to inflammationACTA OPHTHALMOLOGICA, Issue 2010C CURCIO Purpose It's known that severe inflammatory processes may cause limbal stem cell (SC) deficiency decreasing the number of SC niches and changing the microanatomy of these structures. Methods The aim of this study was to evaluate the expression of different SC markers in normal human limbus and to study how an inflammatory conditions can modulate these antigens. To understand the pathological changes in limbal crypts structure due to severe inflammation, a case of corneal melting and perforation in advanced herpes simplex (HSV) disease, two cases of endophthalmitis and a case of fungal infection were analyzed.Samples were examined by immunohistochemistry or immunofluorescence for p63, vimentin, laminin5, integrin (Int) ,6, int ,1, int ,4, ABCG2, desmoglein 3, connexin43, N-cadherin and cytokeratin (K) 12 positivity. We evaluated the anatomical structure of limbal crypts in each case and the positivity for SC marker used to identify SC. Results In normal limbus, the investigated SC markers were positive. In the HSV we didn't observe presence of crypts, whereas in both cases of endophthalmitis crypts were still present but they had an atypical structure: the basal cells in the crypts were "stretched" and endowed by inflammatory cells. In the pathological cases, we observed positivity for K12 while, among SC markers, p63, ABCG2 and connexin43 were still present; the others antigens were variably expressed. Conclusion Different pathologies involving the limbus may result in marked chenges of expression of SC markers within the crypts. [source] Clonal analysis of patterns of growth, stem cell activity, and cell movement during the development and maintenance of the murine corneal epitheliumDEVELOPMENTAL DYNAMICS, Issue 4 2002J. Martin Collinson Abstract Patterns of growth and cell movement in the developing and adult corneal epithelium were investigated by analysing clonal patches of LacZ -expressing cells in chimeric and X-inactivation mosaic mice. It was found that cell proliferation throughout the basal corneal epithelium during embryogenesis and early postnatal life creates a disordered mosaic pattern of LacZ+ clones that contrasts with patterns of proliferation and striping produced during the later embryonic stages of retinal pigmented epithelium development. The early mosaic pattern in the corneal epithelium is replaced in the first 12 postnatal weeks by an ordered pattern of radial stripes or sectors that reflects migration without mixing of the progeny of clones of limbal stem cells. In contrast to previous assumptions, it was found that maturation of the activity of limbal stem cells and the pattern of migration of their progeny are delayed for several weeks postnatally. No evidence was found for immigration of the progeny of stem cells until the 5th postnatal week. There are approximately 100 clones of limbal stem cells initially, and clones are lost during postnatal life. Our studies provide a new assay for limbal and corneal defects in mutant mice. © 2002 Wiley-Liss, Inc. [source] Human immature dental pulp stem cells share key characteristic features with limbal stem cellsCELL PROLIFERATION, Issue 5 2009B. G. Monteiro Objectives:, Limbal stem cells (LSC) are self-renewing, highly proliferative cells in vitro, which express a set of specific markers and in vivo have the capacity to reconstruct the entire corneal epithelium in cases of ocular surface injury. Currently, LSC transplantation is a commonly used procedure in patients with either uni- or bilateral total limbal stem cells deficiency (TLSCD). Although LSC transplantation holds great promise for patients, several problems need to be overcome. In order to find an alternative source of cells that can partially substitute LSC in cornea epithelium reconstruction, we aimed at investigating whether human immature dental pulp stem cells (hIDPSC) would present similar key characteristics as LSC and whether they could be used for corneal surface reconstruction in a rabbit TLSCD model. Materials:, We used hIDPSC, which co-express mesenchymal and embryonic stem cell markers and present the capacity to differentiate into derivative cells of the three germinal layers. TLSCD was induced by chemical burn in one eye of rabbits. After 30 days, the opaque tissue formed was removed by superficial keratectomy. Experimental group received undifferentiated hIDPSC, while control group only received amniotic membrane (AM). Both groups were sacrificed after 3 months. Results and conclusions:, We have demonstrated, using immunohistochemistry and reverse transcription,polymerase chain reaction, that hIDPSCs express markers in common with LSC, such as ABCG2, integrin ,1, vimentin, p63, connexin 43 and cytokeratins 3/12. They were also capable of reconstructing the eye surface after induction of unilateral TLSCD in rabbits, as shown by morphological and immunohistochemical analysis using human-specific antibodies against limbal and corneal epithelium. Our data suggest that hIDPSCs share similar characteristics with LSC and might be used as a potential alternative source of cells for corneal reconstruction. [source] Quest for limbal stem cellsCLINICAL & EXPERIMENTAL OPHTHALMOLOGY, Issue 1 2006Harminder S Dua MD PhD No abstract is available for this article. [source] | |||||||||||||