Biological therapy involves the use of living organisms, substances derived from living organisms, or laboratory-produced versions of such substances to treat disease.
In a wonderful example of biological therapy, a team of Otolaryngologists from the Harvard Medical School injected a healthy gene into the ears of mice and restored their hearing.
The research team focused their study purely on the hearing loss treatment of a genetic disorder called Usher Syndrome. Those born with type I and II, experience deafness and balance dysfunction. Those with type III suffer profound hearing loss later in life.
The culprit gene is called Ush1c, which if mutated, causes deafness in the Usher Syndrome. So the scientists found a virus that carries a normal copy of the Ush1c gene. It’s the first time scientists found a virus that can enter the inner ear and introduce the health gene to the inner and outer hair cells needed for normal hearing levels.
“Delivery of a normal copy of the mutated gene, Ush1c, to the cochlea soon after the mice were born led to high levels of Ush1c protein in outer and inner hair cells, repair of damaged hair cell bundles, and a robust improvement in hearing and balance behaviour, enabling profoundly deaf mice to hear sounds at the level of whispers,” a statement published alongside the research said.
The virus (called the adeno-associated virus) that carries the healthy gene has very little impact on humans. That’s fortunate because the gene transfer method can be used with human tissue with success. Using vestibular tissue, University College London academics were able to show the virus could transfer the gene to the human tissue in culture. “They did a lot of proof of concept in mice,” Forge says. “The bit we did is the extra bit to show this could work in people.”
“They can restore the hearing defect by the gene transfer,” Andrew Forge an emeritus professor of auditory cell biology at University College London and author on the first paper.