title: Stem cell activity in the developing human cornea.
abstract: The adult cornea harbors stem cells (SCs) in its periphery, in a niche known as the limbus. Over the past 2 decades there has been substantial research into these adult corneal SCs, their limbal niche, and their therapeutic applications. However, few studies have investigated how this niche and its SCs develop in humans. To better characterize this development, human fetal corneas from 8.5- to 22-weeks'-gestation (n = 173), neonatal (n = 2), and adult (n = 10) specimens were obtained. Histological and immunohistochemical assessments were conducted to determine embryological changes and expression of developmental and SC-related genes. Fresh fetal corneas were explanted to propagate corneal progenitors and cells characterized using reverse transcription-polymerase chain reaction, immunohistochemistry, flow cytometry, and colony-forming assays. A novel "ridge-like" structure was identified, circumscribing the fetal cornea, which we hypothesize represents the rudimentary SC niche. Immunohistochemistry disclosed "stem-like" cells across the cornea, becoming confined to this ridge with increasing gestational age. In addition, for the first time, pure long-term cultures of fetal corneal epithelium, which displayed phenotypical and functional properties similar to those of adult limbal SCs, were established. Optimization of culture techniques and purification of this SC population will allow for further investigation of their proliferative ability, with potential research and clinical applications. This study expands our understanding of limbal niche development and opens new avenues for investigation.
authors.affiliation: Department of Pathology, School of Medical Sciences, Vision Science, University of New South Wales, Sydney, New South Wales 2052, Australia.
authors.forename: Sarah B
authors.initials: SB
authors.lastname: Davies
authors.forename: Jeanie
authors.initials: J
authors.lastname: Chui
authors.forename: Michelle C
authors.initials: MC
authors.lastname: Madigan
authors.forename: Jan M
authors.initials: JM
authors.lastname: Provis
authors.forename: Denis
authors.initials: D
authors.lastname: Wakefield
authors.forename: Nick
authors.initials: N
authors.lastname: Di Girolamo
mesh_terms: D000328:Adult; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D003315:Cornea / Q000033:anatomy & histology / Q000166:cytology* / Q000648:ultrastructure; D019573:Epithelium, Corneal / Q000166:cytology / Q000378:metabolism; D005333:Fetus / Q000166:cytology; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D007231:Infant, Newborn; D016850:Limbus Corneae / Q000033:anatomy & histology / Q000166:cytology* / Q000648:ultrastructure; D008565:Membrane Proteins / Q000378:metabolism; D008855:Microscopy, Electron, Scanning; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000166:cytology* / Q000378:metabolism
chemical_list: C081876:CKAP4 protein, human; D008565:Membrane Proteins