Today researchers announced that they've been able to restore tonal hearing in guinea pigs with the new method of gene delivery.
The team implanted “bionic ears” in deaf guinea pigs, whose auditory systems are very similar to humans’. With the device, then, they delivered DNA that coded for a protein called brain-derived neruotrophic factor (BDNF), which encourages nerves to grow. The DNA was taken up by cells in the cochlea and, after two weeks, the nerves had grown significantly toward the electrodes. When the guinea pigs’ hearing was tested they found that animals that were once completely deaf had their hearing restored to almost normal levels.
It’s unclear, however, whether the treatment will work long-term: neuron production in the guinea pigs dropped off six weeks after the gene therapy. Researchers are also unsure whether tones heard after this treatment accurately reflect how they sound with normal hearing.
The technique is very close to being ready for human trials, where some of these questions should be answered. If it proves successful in clinical trials, the technique of combining gene therapy with device could also be used for other implants like retinal prosthesis and deep brain stimulation.