Abstract
Purpose :
Trehalose is a naturally occurring bioprotective disaccharide in non-mammalian species, allowing survival in unfavourable environments. It acts as a signalling molecule by activating autophagy and reducing cell death associated with apoptosis and inflammation. It is currently used clinically in ocular surface disease and is shown in vivo to be neuroprotective in neurodegenerative disease including Parkinson’s Disease, Huntington’s Disease and Amyotrophic Lateral Sclerosis. Its potential as a neuroprotective agent in glaucoma has also therefore been postulated. We hypothesised that trehalose could be demonstrated in vitro and in vivo to have a neuroprotective effect in neurodegenerative insults.
Methods :
Trehalose solution was formed by dissolving trehalose in phosphate buffer solution. Toxicity of trehalose was assessed by investigating the cell viability of increasing concentrations of trehalose co-incubated with retinal cells. Cultured retinal cells were treated with insults of cobalt chloride, glutamate, paraquat and homocysteine. They were then co-incubated with either 70 mM trehalose solution or culture media only for 24 hours. Assessment of trehalose-mediated neuroprotection in vitro was achieved using an alamarBlue cell-viability assay. Direct application of trehalose to the optic nerve was used in an optic nerve crush mouse model of neurodegeneration with primary endpoints after 1 week of DARC (Detection of Apoptosing Retinal Cells) imaging and whole retinal RBPMS histology.
Results :
Toxicity studies demonstrated that trehalose was not toxic to retinal cells up to its maximal solubility of 50 mg/mL (146 mM). 70mM trehalose was significantly neuroprotective in vitro in insults of cobalt chloride; IC50 trehalose 520.9μM vs vehicle 390.24μM (p<0.05); and in glutamate; IC50 trehalose 4.761mM vs vehicle 3.231mM (p<0.01). There was no significant neuroprotective effect in paraquat and homocysteine insults. Trehalose was not neurotoxic after 1 week of in vivo study and displayed no adverse effects systemically or locally.
Conclusions :
This work demonstrates that trehalose is safe at high concentrations, is neuroprotective in vitro and not neurotoxic in vivo. Its efficacy in cobalt chloride and glutamate insults suggests a mechanism of action of trehalose which interferes with HIF-1α and calcium excitotoxicity pathways.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.