Seoul: Researchers have found that gene editing tool CRISPR-Cas9 can be delivered directly into the eye to treat age-related macular degeneration (AMD), an advance that may pave way for a new therapy for non-hereditary degenerative diseases.
It is estimated that almost one in every ten persons over 65 has some signs of AMD — a form of blindness which causes distorted vision and blind spots.
In the study, scientists used CRISPR-Cas9 to perform “gene surgery” in the layer of tissue that supports the retina of living mice.
“We believe that this is a new therapeutic modality for the treatment of non-hereditary degenerative diseases,” said Kim Jeong-Hun, Professor at Seoul National University in South Korea.
The most common retinopathies causing blindness are ‘retinopathy of prematurity’ in children, ‘diabetic retinopathy’ and ‘AMD’ in older adults.
In these diseases, abnormally high levels of a protein called Vascular Endothelial Growth Factor (VEGF) are secreted which leads to leakages of blood and fluid into the eye, damaging an area at the centre of the retina called macula.
Currently, injections of anti-VEGF drugs are the most common treatment against AMD.
“The injections tackle the effects, but not the main cause of the problem. By editing the VEGF gene, we can achieve a longer-term cure,” added Kim Jin-Soo, Director of the Center for Genome Engineering at the Institute for Basic Science (IBS) in South Korea.
The CRISPR-Cas9 system works by cutting DNA at a target site, inside the VEGF gene.
For the study, published in the journal Genome Research, the team injected the pre-assembled CRISPR-Cas9 complex into the eyes of a mice model.
They found that the delivering CRISPR-Cas9 complex was more efficient, modified only the VEGF gene and did not affect other genes.