Abstract
Purpose: :
To compare the telomere lengths of human corneal endothelial cells (HCEC) between the central and peripheral areas of younger and older donors.
Methods: :
Human corneas from two groups of donors (younger group: <30 years of age and older group: > 65 years of age) were obtained from NDRI, trephined with 9.5mm diameter trephine, and marked with 6.0mm diameter trephine to separate the cornea into two areas, central and peripheral areas. One of a pair of corneas was cut into quarters, stained with a telomere PNA/FITC probe that specifically binds to telomere repeats, and mounted endothelial side up. HCEC from the central (0–6.0mm) and peripheral areas (6.0–9.5mm) were isolated from the second cornea and put onto the slides by Cytospin. These cells were also stained with the telomere PNA/FITC probe. Confocal microscopy was used to obtain digital images and the average FITC intensity of 100–200 nuclei from five images was analyzed with image software. These intensities were compared between the central and peripheral areas. Also, the average intensity of the younger group was compared to the older group. Ccl185 and 1301 cells were analyzed as controls. Unpaired t–test was used to determine the statistical significance of the data.
Results: :
Data were obtained from 5 younger donors and 6 older donors. The average FITC intensities from the central endothelial areas of tissues were 205.8±4.2 (younger), 194.2±10.5 (older), and 208.1±9.3 (younger), 195.9±10.8 (older) from the peripheral areas. The average intensity of single cells from the central areas was 113.9±31.1 (younger), 107.9±26.1 (older), and 109.9±12.0 (younger), 106.9±32.4 (older) from the peripheral areas. The average intensities of Ccl185 cells and 1301 cells were 50.5±5.0 and 206.9±19.4. Comparison of the results indicates no statistical difference between the central and peripheral areas in each group or between the younger and older group.
Conclusions: :
Central human corneal endothelial cells have similar telomere lengths to cells in the periphery, regardless of donor age, indicating that the reduced proliferative activity of central cells is not due to critically short telomeres.
Keywords: cornea: endothelium • cell survival • cornea: basic science