After being given “landmark” gene therapy by scientists from the United States, deaf mice are now able to hear tiny whisper.
The scientists said that successful restoration of near- normal hearing in animals will soon pave the way for similar treatment to human beings in the near future, reports BBC Health.
Studies have shown that errors that led to sound-sensing hairs in the ear were corrected by natural technology which is now become defective.
In order to correct the defect, the researchers used a synthetic virus to nip in.
“It is unprecedented, this is the first time we have seen this level of hearing restoration,” exclaimed Dr. Jeffrey Holt, a researcher from Boston Children’s Hospital.
Almost half of all forms of deafness are because of an error in the instructions for life-DNA.
In the experiments that were conducted in Boston Children’s home, Harvard Medical School, Massachusetts Eye and ear, it was found that the mice had a generic disorder which is known as Usher syndrome.
This means that there exist some inaccurate instructions for building microscopic hairs inside the ear.
Sets of outer hair cells in healthy ears magnify sound waves and inner ear cells before converting the sound to electrical signals that is transmitted to the brain.
Normally, the hairs form neat V-shape rows. These rows become disorganized in Usher syndrome hence severely affecting hearing.
In the research for treatment, a synthetic virus was developed by the researchers. The developed virus was able to infect the ear with the correct instruction for building the hair cells.
According to the experiments, once profoundly deaf mice was able to hear sounds as low as 25 decibels- approximately the volume of a whisper.
“We were extremely surprised to see such a level of rescue and we are really pleased with what we have achieved,” said Dr. Gwenaelle Geleoc.
Hearing loss can result from about 100 various types of genetic defect. For each one of these, a special type of therapy is required.
Dr Holt said that knowledge on basic science has become more apparent, particularly that of the inner ear. Scientists can now translate this knowledge and use it in future treatment.
But a daunting question will be on the safety of synthetic virus.
It was based on adeno-associated virus, which has already been used in other forms of gene therapy.
Then other questions also arise revolving around “window of opportunity.” The therapy was effective in mice treated immediately after birth but failed to yield any results some 10 days later on.
This research may be an encouraging one but many experts will have to seek for answers concerning delivering this gene therapy at birth.