Action on Hearing Loss Logo
    Total results:
    Search
      Total results:

      Another step forward for gene therapy to treat hearing loss

      Researchers from Harvard Medical School in the US have recently used gene therapy to restore hearing in mice with a particular type of Usher syndrome. Carina Santos, our Translational Research Manager, tells us more about the work, and what it means for using gene therapy to treat hearing loss in people in the future.

      By: Carina Santos | 14 June 2017

      Genes are the master regulators of the characteristics that make us human, from the colour of our eyes to the number of toes we have in each foot, and our hearing is no exception!

      Over half of the cases of hearing loss in children worldwide are due to errors in genes called mutations. In fact, hearing loss acquired during ageing can also be influenced by our genetic make-up. Scientists around the world are working hard to develop gene therapies to correct the mutations that cause hearing loss. Two recent advances made by researchers at Harvard Medical School in the US have brought the prospect of gene therapies for hearing loss closer.

      Delivering genes to the cochlea (inner ear)

      The cochlea is the “hearing” part of the ear, where the sensory hair cells are located. These cells are responsible for translating sound into electrical signals that are sent to the brain, allowing us to hear. So, genetic mutations that affect the way these cells develop or work are likely to cause hearing loss. Scientists working on gene therapy to correct gene mutations in hair cells face the substantial challenge of how to deliver corrected genes to the large number of sensory hair cells in the cochlea, which is hard to access, as it is hidden behind the mastoid bone in our skull, the hardest bone in the body.

      The research, published this month in the scientific journal Nature Biotechnology, presents a new and highly efficient method of delivering corrected genes to 80-90% of sensory hair cells, using a new viral vector called Anc80L65. A viral vector is a harmless virus that scientists engineer to infect specific cells and deliver genes into them. Anc80L65 surpasses existing vectors because its high efficiency allows delivery of genes to different types of hair cells (called inner and outer hair cells), which have complementary and essential roles in the hearing process, as well as vestibular hair cells, which control balance and spatial orientation.

      How gene therapy restored hearing and balance in a mouse model

      Usher syndrome is a genetic disorder that causes profound deafness, blindness and balance disorders. It is responsible for 3-6% of childhood deafness. In a specific type of Usher syndrome, called type 1c, a gene called USH1C is defective, which results in hair cells failing to develop correctly, showing disorganised hair bundles (the hair-like structures on top of the cells that sense sound, and that give hair cells their name), and then dying. In this study, the researchers used mice which have the same mutation in their version of the USH1C gene, which is called Ush1c (naming conventions for genes mean that mouse genes are in lower case, while human genes are capitalised).

      By introducing a corrected version of the Ush1c gene into the inner ear of newborn mice, using the Anc80L65 vector, the researchers were able to restore the correct organization of the hair bundles and improve hearing in the mice by over a thousand-fold, relative to other existing inner ear gene therapy approaches. Along with hearing, balance was also restored in these mice. Although it’s still early days, gene therapy shows promise as a treatment to restore hearing and studies like these are helping to speed up access to these therapies by people.

      What’s next?

      The researchers are now focussed on perfecting the Anc80L65 vector, to limit the delivery of genes to hair cells only. Moreover, although the therapy showed the highest efficiency when used in newborn mice, the best therapeutic window for humans is still to be determined. Unlike in mice, human hearing is fully developed before birth and researchers need to assess if gene therapy would have to be given pre-natally, which would be a significant challenge, or if it will work if administered after birth.

      Find out more

      We depend on your donations so we can fund the best hearing and tinnitus research around the world. Donate today and help us continue our vital work into hearing treatments, so that people can live life to the full again.

      This research was published in the journal Nature Biotechnology.

      Full references:

      Pan B, Askew C, Galvin A, Heman-Ackah S, Asai Y, Indzhykulian AA, Jodelka FM, Hastings ML, Lentz JJ, Vandenberghe LH, Holt JR and Geleoc GS. Gene therapy restores auditory and vestibular function in a mouse model of Usher syndrome type 1c. Nat Biotechnol. 2017 Mar; 35(3):264-272.

      Landegger LD, Pan B, Askew C, Wassmer SJ, Gluck SD, Galvin A, Taylor R, Forge A, Stankovic KM, Holt JR, Vandenberghe LH. A synthetic AAV vector enables safe and efficient gene transfer to the mammalian inner ear. Nat Biotechnol. 2017 Mar; 35(3):280-284.

      You can find out more about our students, and the research we’re funding, in our biomedical research section.

      If you’re interested in finding out more about our research, sign up to receive our Soundbite e-newsletter. It’s a monthly email, filled with the latest news about hearing and tinnitus research.

      Recent Posts

      Deaf-friendly products and technology to help relieve loneliness

      Over nine million people in the UK are either always or often lonely. We know that hearing loss can be sometimes be socially isolating, so this Loneliness Awareness Week we want to encourage anyone with hearing loss who feels lonely to take action. We’ve products and technology to help you, or a loved one, join in again and enjoy a better quality of life.

      By: Sally Bromham
      13 June 2019

      Our top five hearing loops

      If you wear hearing aids but still struggle to follow close-range conversations and what’s happening on TV, a hearing loop could be the answer. It only amplifies the sounds you want to hear, while cutting out background noise. It’s ideal if your hearing aids have a loop or ‘T’ setting. We have hearing loops for the home and portable loops for when you’re out and about. Here’s a roundup of our top five hearing loops, with 10% off between 13 - 21 June 2019.

      By: Sally Bromham
      12 June 2019

      AUDIBLE-S – a clinical trial for people with sudden hearing loss

      A team of researchers and clinicians in London and Sheffield are looking for participants to take part in a clinical trial of a new drug treatment for sudden hearing loss.

      By: Tanjinah Ferdous
      12 June 2019

      Our top 10 conversation listeners

      Do you struggle to follow what’s going on because you can’t always hear what people are saying? If so, a conversation listener will help you join in again. It’s ideal for day-to-day situations, such as family get-togethers, shopping trips, meetings or meals out. You’ll hear more clearly, whether or not you have hearing aids. From 30 May to 7 June, enjoy 10% off in our Conversation Listeners Sale.

      By: Sally Bromham
      30 May 2019