Corneal Endothelial Cell Volume Regulation Disorders in Keratoconus

The study of the permeability to water and urea of plasma membranes of endothelial cells of the normal cornea and cornea with a pronounced form of keratoconus was carried out. Human corneal endothelial cells were obtained from surgical material. Determination of osmotic water permeability (P_f) of normal and keratoconus endothelial cells did not reveal significant differences in the value of this parameter in both groups, where cells had a similar osmotic water permeability (control P_f = 0.53 ± 0.045 cm/s; keratoconus P_f = 0.63 ± 0.041 cm/s) (n = 25; p ≥ 0.05). The urea permeability coefficients (P_u) in both groups also had no statistically significant differences (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 that corneal endothelial cells with keratoconus reduced their volume in a hypertonic medium to a greater extent compared to cells of a healthy cornea. An increase in cell volume as a result of isotonic urea inflow in a hypertonic medium also occurred to significantly higher values compared to normal cells. The conclusion was made about significant changes in the mechanism of regulation of the volume of corneal endothelial cells in keratoconus.