A potential new form of gene therapy which offers hope to people with an eye disease which causes blindness has been developed by Irish scientists.
Retinitis pigmentosa (RP) is a group of rare, genetic disorders that involves a breakdown and loss of cells in the retina, which is the light-sensitive tissue that lines the back of the eye.
Common early stage symptoms include difficulty seeing at night and a loss of side vision, with blindness often developing over time.
Now researchers from Trinity College Dublin and University College London (UCL) have teamed up to pool their expertise in genetics, virology and ophthalmology.
They have started the journey towards a new treatment for the condition, according to the journal, 'Stem Cell Reports'. Scientists have known for some time that mutations in the gene RP2, which is responsible for making a protein essential for normal vision, are associated with RP diseases.
However, there are currently no therapies to treat people living with a number of RP diseases.
The collaborative team behind the exciting new research used a modified common virus to deliver a normal, functioning copy of the RP2 gene into "mini retinas", which had been engineered from stem cells and which contained the defective version of the gene.
The mini retinas developed in UCL simulated the RP2 disease in patients.
Subsequent analysis showed that these mini retinas had successfully taken up the functioning RP2 gene following the viral delivery and produced the essential protein associated with it.
The researchers said that, crucially, the treated mini retinas showed significant improvement - underlining that the approach had rescued them from RP.
Ciara Shortall, PhD researcher in Trinity's School of Genetics and Microbiology, who is one of the main authors of the research, said: "For the last 30 years there has been a lot of buzz about gene therapies and their potential for treating a huge variety of debilitating diseases and disorders, but it is really only recently that science has overcome difficulties associated with such approaches and begun to bring potential therapies far closer.
"In relative terms, it is now fairly easy to replace troublesome genes with functioning versions using non-harmful viruses, which is what we have done here. And while we are still some time and a lot of work away from an approved therapy, it is hugely exciting to have begun a journey that could one day provide an effective treatment to rescue eyesight."
The Trinity team, led by Professor Jane Farrar, used their expertise in genetics and virus creation in the process, while the UCL team, led by Prof Michael Cheetham, took the lead in creating the mini retinas.
According to Prof Cheetham: "It is an important development that we can now reproduce so many elements of inherited disease using these mini retinas. It makes it possible for us to study in detail why people go blind and try to find ways to prevent blindness. It's exciting that the gene therapy seems to be so effective for this form of RP."
It is supported by the Health Research Board of Ireland and Science Foundation Ireland.