American scientists wrote in the latest issue of “Molecular Therapy” that they recently developed a mature mouse model and used gene therapy for the first time to restore the hearing of an aged animal model. The latest method is expected to be applied to humans.

By 2050, one in 10 people is expected to suffer from some form of hearing loss. Of the hundreds of millions of hearing loss cases worldwide, inherited hearing loss is often the most difficult to treat. Hearing aids and cochlear implants have limited relief, but there are currently no treatments available to reverse or prevent this type of genetic disease, prompting scientists to evaluate gene therapy for use as an alternative solution.

In recent years, one of the most promising tools used in gene therapy is the adeno-associated virus (AAV) vector. Although this approach has restored hearing in newborn animals with genetic defects, the vector has yet to demonstrate its capabilities in fully mature or aging animal models. Because humans are born with a fully developed ear, it will be necessary to demonstrate the vector’s capabilities before using this approach to test interventions in humans with inherited hearing loss.

In the latest study, scientists from the Massachusetts Eye and Ear Hospital developed a mature mouse model and successfully demonstrated the efficacy of AAV in an aged animal model for the first time. The model has a mutation similar to a problem with the human gene TMPRSS3, a defect in the TMPRSS3 gene that usually causes people to gradually lose their hearing.

Virus-mediated gene therapy, either alone or in combination with a cochlear implant, has the potential to treat inherited hearing loss, researchers say.