Shear Stress Effects on Schlemm's Canal Cells

Abstract

Nitric Oxide (NO) is a radical produced by endothelial NO synthase (eNOS), which is regulated by shear stress in vascular endothelia. In humans, shear stress levels in Schlemm's Canal (SC) are calculated to be comparable to that of arteries, particularly at elevated intraocular pressure (IOP), a risk factor for glaucoma. To test if NO is part of an IOP regulatory loop, we investigated the relationship between NO and shear stress in SC cells. Cells were seeded into lbidi flow chambers and assayed for effects of continuous shear on cell alignment and NO production. Human umbilical vascular endothelial cells (HUVECS) were used as a positive control. Like HUVECS, SC cells aligned with the direction of flow. NO synthesis in both cell types doubled with an increase in shear from 0.1 to 10.0 dynes/cm2, suggesting that shear regulates NO production in SC cells and consequently may play a role in IOP regulation.