The Tinnitus Specialist Blog
Thoughts and inspiration from a Harley Street tinnitus specialist.
Promising Drug Research To Prevent Noise-Induced Tinnitus
Scientists over at the University of Pittsbburgh (Pitt) School of Medicine have made a breakthrough in the search for a drug to prevent tinnitus after exposure to loud noise.
Thanos Tzounopoulos, Ph.D., associate professor and member of the auditory research group in the Department of Otolaryngology, Pitt School of Medicine says "There is no cure for it, and current therapies such as hearing aids don’t provide relief for many patients,” he said. “We hope that by identifying the underlying cause, we can develop effective interventions".
The team focused on the Dorsal Cochlear Nucleus (DCN), an area of the brain that is an important auditory centre. The DCN has been found in previous tinnitus research on mice to become hyperactive after exposure to loud noise, and fire off random signals even when no sound is present. The new research looked at a particular kind of potassium ion channel, called the KCNQ channel through which potassium ions travel into and out of cells. It turns out that the mice have hyperactive DCN cells because of a reduction in KCNQ potassium channel activity. Normally, these KCNQ channels would act to dampen down the excitability of DCN cells.
The team tested an anti-epilepsy drug called retigabine, which specifically boosts KCNQ channel activity to see whether it could prevent the onset of tinnitus after exposure to loud noise. The researchers found that mice that were treated with retigabine immediately after noise exposure did not develop behavioural signs of tinnitus.
This highlights one of the difficulties of animal studies (I shall leave it for others to discuss the ethics of animal research). The difficulty is that you can't ask a mouse if it has tinnitus. They can only go by behavioural responses to stimuli. However, this research does look very promising.
Dr. Tzounopoulos says. “Tinnitus is a channelopathy, and these KCNQ channels represent a novel target for developing drugs that block the induction of tinnitus in humans.”
The KCNQ family is comprised of five different subunits, four of which are sensitive to retigabine. He and his collaborators aim to develop a drug that is specific for the two KCNQ subunits involved in tinnitus to minimize the potential for side effects.
According to Dr. Tzounopoulos, such a medication could be a very helpful preventive strategy for soldiers and other people who work in situations where exposure to very loud noise is likely.
It will be some time before human trials can start - they will first have to develop a drug that specifically targets the two KCNQ subchannels that are specific to tinnitus and get preliminary confirmation of its safety before human trials can begin - this could take ten years. Although this particular drug research is aimed at preventing tinnitus, rather than curing it, it should give hope to tinnitus sufferers that progress is being made and perhaps one day a medical cure will be found. In the meantime, there are many effective treatments available.
The link to the original article at the University of Pittsburgh can be found here.