July 2019
Volume 60, Issue 9
Free
ARVO Annual Meeting Abstract  |   July 2019
Electrochemical characterization of ciliary epithelium physiology: a theoretical approach
Author Affiliations & Notes
  • Giovanna Guidoboni
    University of Missouri, Chesterfield, Missouri, United States
  • Giulio Bonifazi
    Politecnico di MIlano, Milano, Italy
  • Riccardo Sacco
    Politecnico di MIlano, Milano, Italy
  • Anita Layton
    University of Waterloo, Waterloo, Ontario, Canada
  • Sarah D Olson
    Worchester Polytechnic Institute, Waterloo, Massachusetts, United States
  • Maila C Brucal Hallare
    Norfolk State University, Virginia, United States
  • Brent A Siesky
    Indiana University, Indianapolis, Indiana, United States
  • Carlo Bruttini
    Ophthalmology, University of Pavia, Pavia, Italy
  • Alice Chandra Verticchio Vercellin
    Ophthalmology, University of Pavia, Pavia, Italy
    IRCCS - Fondazione Bietti, Rome, Italy
  • Alon Harris
    Indiana University, Indianapolis, Indiana, United States
  • Footnotes
    Commercial Relationships   Giovanna Guidoboni, None; Giulio Bonifazi, None; Riccardo Sacco, None; Anita Layton, None; Sarah Olson, None; Maila Brucal Hallare, None; Brent Siesky, None; Carlo Bruttini, None; Alice Chandra Verticchio Vercellin, None; Alon Harris, AdOM (I), AdOM (C), CIPLA (C), Oxymap (I), Shire (C)
  • Footnotes
    Support  American Institute of Mathematics, University of Missouri
Investigative Ophthalmology & Visual Science July 2019, Vol.60, 3202. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Giovanna Guidoboni, Giulio Bonifazi, Riccardo Sacco, Anita Layton, Sarah D Olson, Maila C Brucal Hallare, Brent A Siesky, Carlo Bruttini, Alice Chandra Verticchio Vercellin, Alon Harris; Electrochemical characterization of ciliary epithelium physiology: a theoretical approach. Invest. Ophthalmol. Vis. Sci. 2019;60(9):3202.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Purpose : The ciliary epithelium (CE) is the primary site of aqueous humor (AH) production, which results from the combined action of ultrafiltration and active ionic secretion. The modulation of ionic secretion is an important target for drug therapy in glaucoma, and therefore it is important to identify the main factors contributing to it. Since several ion transporters have been hypothesized as important players in CE physiology, we propose a theoretical approach to characterize their role in determining the electro-chemical and fluid-dynamical CE conditions.

Methods : We consider two different models (M0 and M1) for the same fundamental CE unit composed of one pigmented epithelial cell and one non-pigmented epithelial cell (Fig. 1). The CE unit (I) is located between the stroma (S) and the posterior chamber (P). In M0, we include: (i) the Na+-Cl--K+ symporter and the K+ uniporter on the S-CE membrane; and (ii) the Na+-K+ pump and the K+ and Cl- uniporters on the CE-P membrane (Fig.1a). M1 is an enrichment of M0 to include also: (i) the Cl--HCO3- and Na+-H+ antiporters on the S-CE membrane; (ii) the Cl--HCO3- antiporter on the CE-P membrane; and (iii) carbonic anhydrase reaction inside CE (Fig.1b).

Results : Starting from available data on ion concentrations on the S and P sides, balance equations for mass and electric charge are utilized to calculate the electro-chemical variables characterizing CE in the assumptions of M0 and M1. Fig. 2 shows a comparison between experimental data and model predictions for (i) intracellular concentrations of Na+ and K+, and (ii) magnitudes of the transmembrane electric potential. M1 results are of the same order of magnitude as experimental data, thereby providing evidence that the Cl--HCO3- and Na+-H+ antiporters on the S-CE membrane, the Cl--HCO3- antiporter on the CE-P membrane, and the carbonic anhydrase reaction play a crucial role in determining the CE electro-chemical conditions.

Conclusions : This innovative mathematical modeling may enhance our understanding of aqueous humor dynamics and pathophysiology. Our model holds promise for assisting in diagnosing diseases of the eye and for testing new ophthalmic medications.

This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.

 

Fig. 1: Schematic representation of model M0 (a) and model M1 (b).

Fig. 1: Schematic representation of model M0 (a) and model M1 (b).

 

Fig. 2: Comparison between experimental data and model predictions. [1] Bowler et al (1996); [2] Wiederholt et al (1986); [3] Wu et al 2003

Fig. 2: Comparison between experimental data and model predictions. [1] Bowler et al (1996); [2] Wiederholt et al (1986); [3] Wu et al 2003

×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×