Electro-fluid dynamics of aqueous humor production: simulations and new directions.
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
Purpose: to theoretically investigate the role of bicarbonate ion (HCO−
3
) on the nonpigmented transepithelial potential di erence Vm, the sodium potassium pump
(Na/K) and the active secretion of aqueous humor.
Methods: a three-dimensional mathematical model is proposed to isolate the roles
of HCO−
3
and Na+, which are di icult to investigate experimentally. The model
combines the velocity-extended Poisson-Nernst-Planck equations to describe ion
electrodi usion and the Stokes equations to describe aqueous humor flow into the
basolateral space adjacent to the nonpigmented ephitelial cells.
Results: Computations show that Vm is close to baseline experimental measurements
(on monkeys) in the range [−2.7, −2.3]mV only if HCO−
3
is included in the simulation.
The model is also capable of reproducing the flow of Na+ exiting the cell and the
flow of K+ entering the cell, in accordance with the physiology of the Na/K pump.
The simulated Na/K ratio is 1.53, which is in very good agreement with the theoretical
value of 1.5.
Conclusion: Model simulations suggest that HCO−
3
inhibition may prevent physiologically correct baseline values of the nonpigmented transepithelial potential di erence and Na/K ATPase function. This may provide useful indication in the design of
medications that decrease the active secretion of aqueous humor, and supports the advantage of using mathematical models as a noninvasive complement of animal
models.
3
) on the nonpigmented transepithelial potential di erence Vm, the sodium potassium pump
(Na/K) and the active secretion of aqueous humor.
Methods: a three-dimensional mathematical model is proposed to isolate the roles
of HCO−
3
and Na+, which are di icult to investigate experimentally. The model
combines the velocity-extended Poisson-Nernst-Planck equations to describe ion
electrodi usion and the Stokes equations to describe aqueous humor flow into the
basolateral space adjacent to the nonpigmented ephitelial cells.
Results: Computations show that Vm is close to baseline experimental measurements
(on monkeys) in the range [−2.7, −2.3]mV only if HCO−
3
is included in the simulation.
The model is also capable of reproducing the flow of Na+ exiting the cell and the
flow of K+ entering the cell, in accordance with the physiology of the Na/K pump.
The simulated Na/K ratio is 1.53, which is in very good agreement with the theoretical
value of 1.5.
Conclusion: Model simulations suggest that HCO−
3
inhibition may prevent physiologically correct baseline values of the nonpigmented transepithelial potential di erence and Na/K ATPase function. This may provide useful indication in the design of
medications that decrease the active secretion of aqueous humor, and supports the advantage of using mathematical models as a noninvasive complement of animal
models.
Date Acceptance
2016-09-01
Citation
Journal for Modeling in Ophthalmology, 1 (2), pp.48-58
Publisher
JMO
Start Page
48
End Page
58
Journal / Book Title
Journal for Modeling in Ophthalmology
Volume
1
Issue
2
Copyright Statement
© Journal for Modeling in Ophthalmology 2016. (Open access)
Identifier
https://www.modeling-ophthalmology.com/index.php/JMO/article/view/30
Publication Status
Published
Date Publish Online
2016-12-15