# The Role of Giant Vacuoles and Pores of Schlemm's Canal Endothelial Cells in Regulating Aqueous Outflow

> **NIH NIH F30** · BOSTON UNIVERSITY MEDICAL CAMPUS · 2022 · $51,752

## Abstract

ABSTRACT
Primary open-angle glaucoma is a leading cause of blindness worldwide. A primary risk factor for development
and progression of glaucoma is elevation of intraocular pressure, caused by increased resistance in the aqueous
humor outflow pathway. Most of the resistance is believed to be generated in the juxtacanalicular connective
tissue (JCT) and modulated by the inner wall endothelium of Schlemm’s canal and its pores. The mechanisms
that regulate aqueous outflow resistance remain unclear in normal and glaucomatous eyes, and only a couple
newly-approved medications target this site of resistance. To traverse through the outflow pathway, aqueous
humor passes through Schlemm’s canal endothelial cells in transient, pressure-driven cellular outpouchings,
termed “giant vacuoles,” (GV). Pores, small openings in GVs, allow aqueous humor to enter into Schlemm’s
canal from the endothelium. In glaucoma, previous studies have shown a reduction in the number of GV and
pores. The overall goal of this project is to understand the role of giant vacuoles and pores of Schlemm’s canal
endothelial cells in regulating aqueous outflow. To do this, innovative technology will be used to observe and
explore possibile factors (cytoskeletal dynamics and cellular connectivity) that influence the endothelial cells’
ability to form giant vacuoles in new perspectives. First, a novel microfluidic device will be used in conjunction
with live-cell imaging to capture real-time cytoskeletal dynamics of primary Schlemm’s canal endothelial cells in
3D cell culture. Secondly, serial block-face scanning electron microscopy will be used to analyze thousands of
serial images along the inner wall of Schlemm’s canal of ex-vivo perfused human donor eyes. With 3D
reconstruction of cellular geometries, the shapes of endothelial cells and their connections to underlying JCT
cells and matrix will be analyzed and accurately quantified for the first time. Cells will be analyzed in different
flow-types (high-, low-, and non-flow areas) based on fluorescent tracer distributions on global images to
investigate how cellular connections affect the amount of flow going to certain regions around the circumference
of the eye. The specific aims of this proposal are: 1) To observe cytoskeletal dynamics during giant vacuole
formation in real time and determine monolayer permeability and hydraulic conductivity in response to a rho-
kinase inhibitor or dexamethasone in primary Schlemm’s canal endothelial cells using a novel microfluidic device;
and 2) To determine how cellular connections between Schlemm’s canal endothelial cells and underlying
juxtacanalicular tissue cells/matrix modulate giant vacuole and pore formation and their contribution to regulation
of segmental outflow using serial block-face scanning electron microscopy. The results of these studies will
advance our understanding of the role of giant vacuoles and pores of Schlemm’s canal endothelial cells in
regulating aqueous humor outflow...

## Key facts

- **NIH application ID:** 10311490
- **Project number:** 5F30EY030318-03
- **Recipient organization:** BOSTON UNIVERSITY MEDICAL CAMPUS
- **Principal Investigator:** David L Swain
- **Activity code:** F30 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $51,752
- **Award type:** 5
- **Project period:** 2020-01-01 → 2024-03-14

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10311490

## Citation

> US National Institutes of Health, RePORTER application 10311490, The Role of Giant Vacuoles and Pores of Schlemm's Canal Endothelial Cells in Regulating Aqueous Outflow (5F30EY030318-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10311490. Licensed CC0.

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