Researchers at the University of New South Wales School of Medicine in Australia use a type of gene therapy called electrical gene delivery, which uses electric fields to limit gene delivery near cochlear electrodes. This study provides evidence that gene therapy can enrich the hearing of cochlear implants.
When using gene therapy to improve the effect of cochlear implantation, people with varying degrees of deafness a day will distinguish between different instrument tones, such as the jingle of a triangle and the soft tone of a piano. You may feel more complex sounds, such as . Deafness usually occurs after the loss of cochlear hair cells. Cochlear hair cells are special cells in the inner ear that help convert sound vibrations into nerve electrical impulses. This is the process that makes us hear the sound. Since the 1970s, cochlear implants have been put on the market and partially restore hearing by affecting cochlear hair cells. However, current cochlear implants cannot restore normal hearing, and the electrode design has remained basically unchanged in the past few decades. In a completely deaf guinea pig experiment, Jeremy Pinon and colleagues pointed out that gene therapy can improve cochlear implant performance by stimulating the regeneration of cochlear neurons that convert different frequencies into sounds.
Researchers use a type of gene therapy called electrical gene delivery, which uses electric fields to limit gene delivery near the cochlear electrodes (this is related to the way viruses and genes are delivered. Genes that pass genes that have a certain ability to spread). Pinyon et al. injected a DNA solution containing the brain-derived neurotrophic factor (BDNF) gene into the cochlear implant of guinea pigs, and used an electrode array to deliver several short electrical pulses to the cochlear implant. Within a few hours, the cochlear cells received the DNA and began to express Neurotrophin (a protein that helps nerve cell development). The research team tested the hearing of guinea pigs using the auditory brainstem response test or ABR. ABR is a common method used to detect the hearing of newborns. Electrodes are placed on the top of the head of the guinea pig to detect electricity produced by the cochlear nerve fibers in the brain, which is excited in response to sound. Researchers found that the hearing of guinea pigs has improved significantly, and the hearing of guinea pigs that were completely deaf has returned to normal levels. These results provide evidence that gene therapy can enhance hearing in cochlear implants. The researchers then plan to test the cochlear electrical gene delivery technology in clinical trials.