MELBOURNE, Apr 28: Researchers have for the first time used electrical pulses delivered from a cochlear implant to deliver gene therapy, thereby successfully regrowing auditory nerves.
The research, conducted at the University of New South Wales in Australia, also heralds a possible new way of treating a range of neurological disorders, including Parkinson’s disease, and psychiatric conditions such as depression through this way of delivering gene therapy.
“People with cochlear implants do well with understanding speech, but their perception of pitch can be poor, so they often miss out on the joy of music,” UNSW’s Gary Housley, who is the senior author of the research paper said.
“Ultimately, we hope that after further research, people who depend on cochlear implant devices will be able to enjoy a broader dynamic and tonal range of sound, which is particularly important for our sense of the auditory world around us and for music appreciation,” Housley said.
The work centres on regenerating surviving nerves after age-related or environmental hearing loss, using existing cochlear technology.
The cochlear implants are “surprisingly efficient” at localised gene therapy in the animal model, when a few electric pulses are administered during the implant procedure, Housley said.
It has long been established that the auditory nerve endings regenerate if neurotrophins – a naturally occurring family of proteins crucial for the development, function and survival of neurons – are delivered to the auditory portion of the inner ear, the cochlea.
But until now, research has stalled because safe, localised delivery of the neurotrophins can’t be achieved using drug delivery, nor by viral-based gene therapy.
Housley and his team at UNSW developed a way of using electrical pulses delivered from the cochlear implant to deliver the DNA to the cells close to the array of implanted electrodes.
These cells then produce neurotrophins.
“No-one had tried to use the cochlear implant itself for gene therapy,” Housley said, adding “with our technique, the cochlear implant can be very effective for this”.
“While the neurotrophins production dropped away after a couple of months, ultimately the changes in the hearing nerve may be maintained by the ongoing neural activity generated by the cochlear implant,” Housley said.
“We think it’s possible that in the future this gene delivery would only add a few minutes to the implant procedure,” the paper’s first author, Jeremy Pinyon, whose PhD is based on this work, said.
“The surgeon who installs the device would inject the DNA solution into the cochlea and then fire electrical impulses to trigger the DNA transfer once the implant is inserted,” he said. (PTI)
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