Abstract
Purpose :
Adult tissue resident stem cells have been reported in different parts of the human eye and are responsible for the maintenance of tissue homeostasis throughout life. The anterior lens epithelium is a monolayer of cuboidal cells and four different zones (central, germinative, transitional and equatorial zones) have been reported on the basis of proliferation and differentiation. The anterior lens epithelium has the ability to differentiate into lens fibres throughout life. In mice, the adult stem cells were identified in the central zone on the basis of their label retaining property. However, in a recent review, equatorial zone in the human lens was described to contain lens epithelial stem cells. Therefore, the present study aims to identify the location of adult lens epithelial stem cells and characterize the nature of cells in different zones of human anterior lens epithelium.
Methods :
Whole lens were obtained from excised donor globes (n=15) from Rotary Aravind International Eye Bank. Whole mount of the anterior lens epithelium was immunostained for the expression of markers: SOX2, α, β, γ- crystallins, and Connexin-43 (Cx-43). Images were acquired and analyzed using Leica SP8 confocal microscope.
Results :
The central zone measuring about 1.66±0.1mm in diameter consists of 15.8±3.9% cells positive for stem cell marker (SOX2), but negative for the differentiation marker (Cx-43). The epithelial cells in the germinative, transitional and equatorial zones were negative for SOX2 but positive for Cx-43. A distinct pattern of expression of crystallins was observed: α- crystallin expressed throughout the anterior lens epithelium including adult stem cells, transitional and equatorial zones were positive for β-crystallin while equatorial zone was characterized by the presence of late elongation marker γ-crystallin.
Conclusions :
The presence of adult tissue resident stem cells has been identified for the first time only in the central zone of human anterior lens epithelium. Further studies are essential to understand the functional role of these stem cells in maintaining tissue homeostasis throughout life.
This is a 2020 ARVO Annual Meeting abstract.