High oxygen concentrations inhibit Acanthamoeba spp.

Efficacious treatments against Acanthamoeba Keratitis (AK) is challenging, often ineffective and linked to the intragenotype variation in the drug efficacy. Increased oxygen can facilitate host response and can inhibit some organisms. Herein, we report the effect of increased oxygen concentrations on Acanthamoeba spp. growth and its effect on ROS (reactive oxygen species) production. The exposition to pure oxygen could reduce cell growth by at least 60% for Acanthamoeba castellanii Neff, Acanthamoeba polyphaga, and Acanthamoeba griffini. The increase in ROS production confirming that oxygen cell's growth inhibition was due to oxidative stress. Further studies are needed to determine oxygen saturation level, time of oxygen exposition, and number of sessions needed to eliminate the parasite.

Combined Amoebicidal Effect of Atorvastatin and Commercial Eye Drops against Acanthamoeba castellanii Neff: In Vitro Assay Based on Mixture Design.

The establishment of an effective therapeutic agent against Acanthamoeba keratitis (AK), remains until present, an issue to be solved due to the existence of a cyst stage in the life cycle of Acanthamoeba. Moreover, the effectiveness of the current standard therapeutic agents varies depending on the tested Acanthamoeba strains and its resistance pattern. In the present study, two 10-point augmented simplex-centroid designs were used to formulate a three-component mixture system using water, atorvastatin, and Diclofenaco-lepori or Optiben. The amoebicidal effects and in vitro-induced toxicity in a eukaryotic cell line were determined for all experiments. The optimal mixture to inhibit the parasite without inducing toxicity was established in the first plan as 30% Optiben, 63.5% atorvastatin, and 3.1% water. As for the second experimental design, the optimal mixture to inhibit Acanthamoeba with lower toxicity effect was composed of 17.6% Diclofenaco-lepori and 82.4% atorvastatin.