Abstract
Purpose :
The corneal endothelium acts as a barrier and controls the diffusion of fluid and nutrients between the aqueous humor and the stroma through intercellular junctions and the Na+/K+-ATPase pump. The purpose of this study is to assess the influence of intraocular pressure (IOP) and fluid flow on the functionality of the corneal endothelium.
Methods :
Human corneal endothelial cells (CECs) were extracted from donor corneas. Cells were seeded at 2,500 cells/mm2 either on plastic (2D cultures) or on devitalized human corneas (3D tissue model) (N=3 pairs). After 7 days of culture, the tissue-engineered corneal endothelia were placed in a corneal bioreactor in the presence of an IOP of 16 mmHg and fluid flow of 5ul/min for one of the 2 corneas. The mate cornea was cultured without IOP. Following 3 days of culture in the bioreactor, the activity of Na+/K+-ATPase was assessed (ATPase assay, Abcam). Results were relativized using total DNA (Genomic DNA purification Kit, New England Biolabs).
Results :
Na+/K+-ATPase activity of CECs cultured on plastic (2D model) was low (-0,01 ±0.9x10-3 nmol/min/uL/ngDNA). However, the same cells cultured on a devitalized stroma (3D model) showed an increase in Na+/K+-ATPase activity (6.33x10-3 ± 3.9x10-3 nmol/min/uL/ngDNA), which was further increased by 2.38-fold in the presence of IOP (1.5x10-2 ±3.1x10-3 nmol/min/uL/ngDNA). This increase of Na+/K+-ATPase activity in the presence of IOP was also observed using 2 other cell populations. Indeed, in 3D models, the activity of the Na+/K+-ATPase pump following IOP increased 2.0-fold (1.04 x10-3 ±1.24x10-5 nmol/min/uL/ngDNA without IOP and 2.08x10-3 ±7.4x10-5 with IOP); and 2.1-fold (4.40x10-4 ±6.3x10-5 nmol/min/uL/ngDNA without IOP to 9.15x10-4 ±1.4x10-4 with IOP).
Conclusions :
These results indicate that culturing CECs in a 3D environment increases the activity of the sodium-potassium pump, which is further increased by adding IOP. A better understanding of how the in vivo environment influences CEC functionality may help to provide better tissue engineered corneas.
This is a 2021 ARVO Annual Meeting abstract.