Abstract
Purpose :
Acanthamoeba keratitis is a well-known intractable corneal infectious disease in which the conventional antibiotics are ineffective. In this study, we investigated anti-Acanthamoeba effect of exogenous nitric oxide (NO).
Methods :
The most common Acanthameoba that causes keratitis, Acanthameoba castellanii, was axenically cultured and was exposed to various concentrations of NO donors such as sodium nitrite, sodium nitroprusside and NO releasing silica nanoparticles (branched polyethylene imine coated, 100nm sized) for 1 to 7 days (sodium nitrite and sodium nitroprusside: 0, 0.1, 1, 10, 100, and 1000µM; silica nanoparticles: 0, 6.25, 12.5, 25, 50, and 100 µg/ml).
Results :
Sodium nitrite and sodium nitroprusside showed dose dependent inhibitory effect on A. castellanii viability. More prominent inhibitory effect was observed with sodium nitroprusside (less than 10% of organisms survived with 7 days culture with 1000µM) compared to sodium nitrite. NO releasing silica nanoparticles were successfully internalized into amoebic cytoplasm and accumulated in large vacuoles. While blank silica nanoparticles had no inhibitory effect of A. castellanii viability, NO releasing silica nanoparticles showed dose dependent inhibition of A. castellanii viability. Although, the viability was significantly decreased with NO treatment, no cystic transformation of A. castellanii was observed under phase contrast microscope and transmission electron microscope.
Conclusions :
Our results suggest that NO releasing drug platforms including nano-carriers can be a promising therapeutic strategy for Acanthamoeba keratitis.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.