In a recent study, researchers from UCL and Imperial College London found that a derivative of turmeric could be used in eye drops to treat the early stages of glaucoma.
They report a new method to deliver curcumin, extracted from the yellow spice turmeric, directly to the back of the eye using eye drops, overcoming the challenge of curcumin’s poor solubility.
The research team found the eye drops can reduce the loss of retinal cells in rats, which is known to be an early sign of glaucoma.
They are also investigating how the eye drops could be used as a diagnostic tool for a range of conditions.
Glaucoma is a group of eye conditions affecting over 60 million people worldwide that leads to irreversible blindness in 1 in 10 cases.
The condition mainly involves the loss of retinal ganglion cells, a type of neuron located near the surface of the retina.
Stopping the loss of these cells early on has not yet been achieved, so it is a key focus of glaucoma research.
Curcumin is a compound that has shown promise at detecting and treating the neurodegeneration implicated in numerous eye and brain conditions from glaucoma to Alzheimer’s disease.
It has previously been shown to protect retinal ganglion cells when administered orally.
The aim of the study was to find a more reliable method to deliver curcumin.
Previous research has shown that oral administration is difficult.
This is because curcumin has poor solubility. It does not easily dissolve and get absorbed into the bloodstream and would require people to take large amounts of tablets (up to 24 a day) that may cause gastrointestinal side effects.
In the study, the team developed a novel nanocarrier, wherein the curcumin is contained within a surfactant combined with a stabilizer.
Both are known to be safe for human use and are already in existing eye products.
The nanocarrier can be used in eye drops to deliver much higher loads of curcumin than other products in development.
This can increase the drug’s solubility by a factor of almost 400,000 and localizes the curcumin in the eyes instead of throughout the body.
The researchers initially tested the product on cells that are used to model glaucoma, then they conducted trials in rats with eye conditions involving the loss of retinal ganglion cells.
After twice-daily use of eye drops in the rats for three weeks, they found that retinal ganglion cell loss was significantly reduced compared to matched controls and that the treatment was well-tolerated with no signs of eye irritation or inflammation.
The researchers now are hopeful that it could also be used to diagnose Alzheimer’s disease.
Curcumin is known to bind to the amyloid beta protein deposits implicated in Alzheimer’s and can be detected in the retina with fluorescence to highlight the malignant proteins.
The study’s lead author is Professor Francesca Cordeiro (UCL Institute of Ophthalmology, Western Eye Hospital, and Imperial College London).
The study is published in the Scientific Reports.
Copyright © 2018 Knowridge Science Report. All rights reserved.
Journal reference: Benjamin M. Davis et al. Topical Curcumin Nanocarriers are Neuroprotective in Eye Disease, Scientific Reports (2018). DOI: 10.1038/s41598-018-29393-8.
