Distribution of Precursors in Human Corneal Stromal Cells and Endothelial Cells
Received 15 September 2005; accepted 7 July 2006.
Purpose
We identified original tissue-committed precursors with limited self-renewal capacity from human corneal stromal (HCS) cells and human corneal endothelial (HCE) cells, then tried to determine the distribution and proliferative capacity of the precursors.
Design
Experimental study.
Participants
Eighteen human corneas from donors 56 to 68 years old.
Methods
Human corneal stromal cells were divided into groups based on distance from the center of the cornea: <6 mm (central), 6 to 8 mm (paracentral), and 8 to 10 mm (peripheral). Human corneal endothelial cells were separated into 2 groups: <7.5 mm (central) and 7.5 to 10 mm (peripheral) from the center. Each group was subjected to the sphere-forming assay using serum-free medium containing growth factors in floating culture. Sphere numbers and the proliferative capacity of spheres in adherent culture were compared among the groups.
Main Outcome Measures
Density and proliferative capacity of precursors from each area of HCS and HCE cells.
Results
Primary spheres were isolated from all groups of HCS and HCE cells. The rate of primary sphere formation from peripheral HCS cells was higher than those of the other 2 groups, being 1.5-fold greater than in the paracentral cornea and 4-fold greater than in the central cornea. The rate of primary sphere formation by peripheral HCE cells was significantly higher than that by central HCE cells, being 4-fold greater than in the central cornea. There were no differences in the proliferative capacity of HCS and HCE cell spheres from the different areas after adherent culture.
Conclusions
All HCS and HCE cells contain a significant number of precursors, but the peripheral cells have a density of precursors higher than that of the central cells. Precursors from each area do not show differences of proliferative capacity. Our findings may in part explain changes after excimer laser treatment and may have implications for corneal transplantation procedures.
1Department of Corneal Tissue Regeneration, Tokyo University Graduate School of Medicine, Tokyo, Japan.
2Department of Ophthalmology, Tokyo University Graduate School of Medicine, Tokyo, Japan.
3Department of Oral and Maxillofacial Surgery, Tokyo University Graduate School of Medicine, Tokyo, Japan.
Reprint requests to Satoru Yamagami, MD, PhD, Department of Corneal Tissue Regeneration, Tokyo University Graduate School of Medicine, Hongo 7-3-1, Bunkyo-ku, Tokyo, Japan 113-8655.
Manuscript no. 2005-871.
This work was supported in part by the Ministry of Education, Culture, Sports, Science and Technology, Tokyo, Japan (Grant-in-Aid for Scientific Research), and Japan National Society for the Prevention of Blindness, Tokyo, Japan.
ABSTRACT