Speaker
Description
The cornea is the transparent tissue in front of the eye, composed of three main layers: endothelium (a monolayer of cells towards the anterior chamber), stroma and epithelium (towards the tear film). The cornea is kept at the correct hydration, essential for its
transparency, by the endothelium pumping water out of the stroma. In our previous work [1], we showed that local osmosis (water flux generated by the buildup of a concentration gradient in the channel between adjacent endothelial cells, called cleft) is the main driver of the endothelial pump. In this work, we refine our model to investigate another possible mechanism hypothesized in the literature, accounting for the presence of the lactate ion [2].
The model domain includes a well-mixed 0D compartment representing the cell and a 2D compartment representing the cleft. We consider 7chemical species (sodium, potassium, chloride, bicarbonate, carbon dioxide, protons, lactate) and a chemical reaction. We write
equations for fluid and ion balance, accounting for membrane channels and transporters, and for the tight junction closing the cleft on the anterior chamber side. Asymptotic analysis leads to a system of algebraic equations and ODEs, solved iteratively in MATLAB. We parametrize the model by optimizing the membrane permeability to ions against literature values.
With this model, we show the link between transendothelial lactate and water flux, and we investigate the role of bicarbonate [3] in their transport.
Bibliography
@article{1,
author = {Federica Vanone and Alexander J.E. Foss and Francesco Viola and Rodolfo Repetto and Mariia Dvoriashyna},
doi = {10.1098/RSIF.2025.0167;WGROUP:STRING:PUBLICATION}, issn = {17425662},
issue = {229},
journal = {Journal of the Royal Society Interface}, month = {8},
publisher = {Royal Society Publishing},
title = {A mathematical model of corneal endothelium pump function}, volume = {22},
url = {/doi/pdf/10.1098/rsif.2025.0167}, year = {2025},
}
@article{2,
author = {Joseph A. Bonanno},
doi = {10.1016/J.EXER.2011.06.004}, issn = {00144835},
issue = {1},
journal = {Experimental Eye Research}, month = {2},
pages = {2},
pmid = {21693119},
publisher = {NIH Public Access},
title = {“Molecular Mechanisms Underlying the Corneal Endothelial Pump”}, volume = {95},
url = {/pmc/articles/PMC3199349/ /pmc/articles/PMC3199349/?report=abstract https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3199349/},
year = {2012},
}
@article{3,
author = {Shimin Li and Edward Kim and Joseph A. Bonanno}, doi = {10.1152/AJPCELL.00095.2016},
issn = {15221563},
issue = {1},
journal = {American Journal of Physiology - Cell Physiology}, month = {7},
pages = {C116}, pmid = {27225657},
publisher = {American Physiological Society},
title = {Fluid transport by the cornea endothelium is dependent on buffering lactic acid efflux},
volume = {311},
url = {/pmc/articles/PMC4967133/ /pmc/articles/PMC4967133/?report=abstract https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4967133/},
year = {2016},
}
