Defining the Limbal Stem Cell Niche

Abstract

The cornea forms the front transparent cover of the eye which is reputed to be maintained by a population of adult stem cells located at the junction of the cornea and the white sclera of the eye. This area is known as the limbus and the stem cells as limbal stem cells. The desire to describe the exact location of the stem cells at the limbus has led to several descriptions of anatomical features that could provide the niche environment for these cells. Our laboratory, acting upon evidence that the limbus is not the sole location of adult stem cells in the cornea, analysed whether the limbal stem cells could exist outside of the limbal environment and whether they would still retain the properties required to maintain the corneal surface.

Biofabrication of Artificial Stem Cell Niches in the Anterior Ocular Segment

“…The focal stromal projections are finger-like protrusions of the limbal stroma into the limbal epithelium that contain a central blood vessel. The complexity of these "niche-like" structures suggests that the maintenance of the corneal epithelium involves not only the prevailing theorised niche for corneal stem cells of unipotent LESCs, but also the oligopotent LESCs distributed throughout the corneal basal epithelium and the putative LESCs observed at the base of the palisades of Vogt [31,72,[81][82][83][84]. LESCs are responsible for the homeostasis of the corneal epithelial cells by renewing and repopulating the central corneal epithelium every 7-10 days through proliferation, differentiation and centripetal migration from the limbus towards the central cornea, where they mature and become stratified wing and superficial, squamous corneal epithelial cells.…”