Protecting auditory nerve cells using genetic therapy​

Principal Investigator - Dr Rachael Richardson
Principal Investigator - Dr Andrew Wise
Principal Investigator - Prof Robert Shepherd
Collaborating Researcher - Prof Stephen O'Leary
Research Assistant - Brianna Flynn

Background

Sensorineural hearing loss is caused by damage to the sensory hair cells in the inner ear.

The application of nerve survival factors, known as neurotrophins, to the deaf cochlea prevents the degeneration of auditory neurons which occurs following the loss of the hair cells.

To enhance and maintain the surviving neurons in deaf cochlear implant (CI) recipients, we are researching methods to deliver neurotrophic factors into the cochlea in a variety of ways. These types of studies have important potential for clinical applications because we envisage a next generation of CIs that can actively deliver drugs which can either preserve residual hearing or prevent further degeneration of primary auditory neurons.

In addition, these techniques may be eventually applied to implants in other parts of the nervous system, such as the retina of the eye.

Our research

The purpose of this work is to preserve or regenerate the highly structured neural organisation of the cochlea using gene therapy techniques.

We previously discovered that flooding the cochlea with neurotrophins protected auditory neurons after deafness, but we noticed that the nerve fibres grew abnormally which could result in a confusing sound perception with a cochlear implant. Using clues from the normal development of the inner ear, we proposed that a more localised source of neurotrophins will provide the neurons with survival signals directional cues to guide their growth to the right location.

Gene therapy techniques allow the cochlea’s own cells to produce neurotrophins just as hair cells would normally do. This study provides the first steps towards controlling nerve growth in the cochlea after hearing loss.

If we can achieve long-term nerve survival and controlled re-growth of nerve fibres after hearing loss, then we can potentially improve bionic ear performance. 

Funding

  • NHMRC

  • Action on Hearing Loss (formerly the Royal National Institute for Deaf People)

  • Garnett Passe and Rodney Williams Memorial Foundation

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Projects_Hearing_Genetherap.jpg

Re-growing nerve fibres

A microscopy image showing a cross section of the cochlea following infusion with a gene therapy vector.Cells (green) have taken up this vector which is proposed to guide the regrowth of hearing nerve fibres (red) in the right direction after hearing loss.

 


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