Cell Volume Regulation of Endothelial Cells Is Impaired in Keratoconus Cornea

In this work the permeability to water and urea of plasma membranes of endothelial cells of normal corneas and corneas with keratoconus was investigated. The endothelial cells were obtained from surgery material. Measurements of osmotic aqueous permeability (Pf) of endothelial cells in normal and in keratoconus did not reveal significant differences of this parameter in the two studied groups. The control cells and the cells from keratoconus cornea have similar osmotic water permeability (control cells, P-f = 0.53 +/- 0.045 cm/s; keratoconus cells, P-f = 0.63 +/- 0.041 cm/s; n = 25; p > 0.05). Neither coefficient of urea permeability differed significantly in these groups (control, P-u = 0.049 +/- 0.003 cm/s; keratoconus, P-u = 0.056 +/- 0.003 cm/s; n = 25; p > 0.05). Analysis of cell volume dynamics based on exponential approximation showed a more pronounced decrease of the cell volume of endothelial cells from keratoconus cornea in hypertonic medium in comparison with the cells from normal cornea. The increase of cell volume caused by isotonic entering of urea into the cells in hypertonic medium also was more pronounced in these cells in comparison with the normal ones. We conclude that there are significant changes in cell volume regulating mechanism in keratoconus cornea endothelial cells.