Mesenchymal stem cells in the human corneal limbal stroma.
OBJECTIVE
Peripheral and limbal corneal stromal cells (PLCSCs), which contain keratocytes, have a complex phenotype. Knowledge of keratocyte cell properties, function, and origin is limited. Evidence available thus far has suggested both mesenchymal stromal and hematopoietic characteristics. Multipotent mesenchymal stromal cells (MSCs) are found in an increasing number of tissues and are the subject of considerable interest and investigation in the disciplines of tissue engineering, immunology, gene therapy, and oncology.


METHODS
Isolated PLCSCs were characterized by markers aldehyde dehydrogenase and keratocan, cultured, and analyzed against a set of criteria for the identification of MSCs developed by the International Society of Cellular Therapy (ISCT). PLCSCs were directly compared to fetal liver MSCs (flMSCs). Additional cell surface markers were also used to quantify differentiation, which was also performed on both cell types.


RESULTS
PLCSCs were found to be plastic adherent, displayed the correct profile and proportions of CSMs, and demonstrated trilineage potential in accordance with the ISCT guidelines. Furthermore, PLCSCs displayed a high degree of similarity to flMSCs and this likeness extended into the non-ISCT MSC cell surface markers and trilineage differentiation, which were often but not always comparable.


CONCLUSIONS
Herein we report a novel observation that PLCSCs conform to all the ISCT criteria and are therefore MSCs. Furthermore, this study has identified the limbal stroma as yet another MSC niche and presents a new perspective on the role of the PLCSC.
Division of Ophthalmology and Visual Sciences, University of Nottingham, Queen's Medical Centre Campus, Nottingham, UK.
Matthew James
MJ
Branch
Khurram
K
Hashmani
Permesh
P
Dhillon
D Rhodri E
DR
Jones
Harminder Singh
HS
Dua
Andrew
A
Hopkinson
D000444:Aldehyde Dehydrogenase / Q000378:metabolism; D018952:Antigens, CD34 / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002448:Cell Adhesion; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D003319:Corneal Stroma / Q000166:cytology* / Q000378:metabolism; D053686:Fetal Stem Cells / Q000166:cytology* / Q000378:metabolism; D005434:Flow Cytometry; D005865:Gestational Age; D006801:Humans; D016850:Limbus Corneae / Q000166:cytology; D008099:Liver / Q000196:embryology*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D010641:Phenotype; D011509:Proteoglycans / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction
D018952:Antigens, CD34; D015415:Biomarkers; C490948:KERA protein, human; D011509:Proteoglycans; D000444:Aldehyde Dehydrogenase