Abstract
Purpose: :
The limbal niche, habitat of the limbal epithelial stem cells (LESC), facilitates their function by means of physical support and chemical signaling. In this study, the impact of age on the topography of the niche, as well as its role on the phenotype of cultured LESCs was investigated.
Methods: :
Ex vivo
Results: :
Imaging of the limbus from different aged donors showed that the area populated by crypts significantly changed with age and was sharply reduced after 60-65 years. The niche microstructures also became smoother and decreased in number with increase of donor age. The phenotype assessment of LESC cultures showed peak activity of telomerase activity and telomere length between 40 and 50 years of age and similar reduced levels in cells from younger and older donors. These results also correlated with a rise of keratin 15 expression in LESCs from the middle-aged donors. Despite the dramatic effect of age on niche topography, the CFE of LESCs cultured from a spectrum of different ages remained unchanged.
Conclusions: :
effect of age on the structural and phenotypic characteristics of the limbal niche and LESCs was studied for the first time in more than 100 cadaveric donors. The niche structures were reduced in area and definition with increased age, however a peak of stem cell-related phenotypic characteristics was observed in the age group of 40 to 50 years. These results have significant clinical value as although they suggest the potential superiority of LESCs harvested from middle aged donors, they also establish the suitability of LESCs harvested from the entire donor age spectrum for cultured LESC therapy.
Keywords: cornea: epithelium • cornea: basic science • aging