Gene therapy developed at ANU could help save eyesight

The therapy is working on preventing the loss of eyesight from dry age-related macular degeneration.

Dry AMD is a common disorder that is caused by damage to the macula - the part of the eye that is responsible for our sharpest vision.

Dr Joshua Chu-Tan, from The John Curtin School of Medical Research, is developing a new eye injection that has the potential to stop the progression of the disease.

The research is yet to be trialed on humans but has seen positive results in animals.

"It's a real problem and it's the leading cause of blindness in the developed world," Dr Chu-Tan said.

"For about 90 per cent of patients who have dry AMD there's no cure or therapy."

Dry AMD is a common disorder that is caused by damage to the macula - the part of the eye that is responsible for our sharpest vision.

It can take years for signs of dry AMD to be found in the eye and often by the time it is diagnosed the disease is irreversible.

It is estimated that by 2020, there will be 196 million people living with AMD worldwide.

"If doctors find there are traces of dry AMD advancing in your retina there is nothing they can do for you - your sight can't be saved."

Dr Chu-Tan has been researching preventative gene therapy using tiny molecules called microRNA that he describes as "the gods of gene regulation". He has used microRNA to target the causes of AMD.

"We know inflammatory pathways plays a major role in AMD and tiny molecules called microRNA can fight them in a multi-pronged way," he said.

"When we inject anti-inflammatory mircoRNA into the eye we see a decrease in genes responsible for inflammation and cell death, as well as a slowing in the damage progression of the retina.

"We are not just cutting the weed when it grows, we are trying to pull the weed out by its roots."

Dr Chu-Tan said a specific microRNA, microRNA-124, had great promise as a preventative treatment for AMD as an alternative to the eye injections offered now.

The break through came about five years ago when it was discovered patients with AMD had almost no microRNA-124, compared to a healthy retina.

"We thought maybe if we tried to supplement the microRNA124 then we can ameliorate the damage," he said.

"By injecting a cocktail of these molecules we think we can slow the progression of this disease and hopefully halt vision loss.

"When we compare an AMD patient to a healthy individual, the healthy individual has a lot of this microRNA-124 all over their retina, whereas in an AMD patient there is none.

"However in an AMD patient's periphery of the retina, where there is no damage, there is microRNA-124."

The experiments done so far have been on animals but Dr Chu-Tan said he hoped clinical trials could be possible within the next 10 years.

"They are quite promising preliminary experiments," he said.

He said when the animals were treated with the molecule their retinas were functioning better.

Dr Chu-Tan will be presenting his research at a TEDx talk in New Zealand on 25 August.