You may have recently seen the headlines in your newspaper or online along the lines of “New breakthrough pill could cure tinnitus.” This is game-changing news if true – so what’s the real story behind the headline?
The headlines were in response to an article published in the journal PLoS Biology.
Researchers led by a team from the University of Arizona have suggested that neuroinflammation (inflammation within the brain or spinal cord) may cause tinnitus. Inflammation is the body’s response to damage or infection, so noise-induced hearing loss (NIHL) could cause inflammation in the auditory pathway, triggering tinnitus.
Investigation
To investigate this idea, researchers looked at mice who had NIHL and tinnitus. These mice had higher levels of molecules and cells known to be involved when neuroinflammation occurs. One of these molecules is called tumour necrosis factor-alpha (TNF). When the researchers deactivated the gene responsible for TNF, they found that no neuroinflammation was present, and the mice no longer showed signs of tinnitus. When TNF was blocked using drugs in another group of mice, they didn’t show signs of tinnitus after being exposed to loud noise. To double-check the connection, further groups of mice received infusions of TNF, and this was shown to trigger tinnitus.
How long till a pill?
Now, this is where the stories and the headlines depart somewhat. In order for there to be a pill for tinnitus, these results need to translate over to humans, and work on this has not yet been carried out. Although there are a number of drugs that block TNF in humans, each would need to be rigorously tested. This process could take a number of years.
ENT surgeon Don McFerran, the leading tinnitus expert, explained:
“The name (TNF) Tumour Necrosis Factor is not very helpful, suggesting that it is only associated with disease processes. In fact, TNF is a chemical that is produced by many cells in the body and it contributes to normal body processes, particularly processes related to the immune system, such as fighting off infections. It is one of a family of normal cellular chemicals called cytokines and most of the time it is a normal, helpful part of us.
There are certain diseases in which abnormal TNF activity is thought to contribute to the disease and anti-TNF drugs have been in use in selected patients for around twenty years. There are no reports in this time period that these drugs help tinnitus – indeed, the opposite is true – there are reports that tinnitus can develop in people being treated with anti-TNF drugs. This is not to say that anti-TNF drugs definitely have no role in tinnitus – just that the ones that we have already produced do not seem to help. Different anti-TNF drugs work in different ways and it is still possible that there is an anti-TNF drug that may help tinnitus.”
He added this warning:
“There is a salutary tale regarding anti-TNF drugs in a different condition – multiple sclerosis (MS). Initial animal experiments suggested that anti-TNF drugs could be very helpful in counteracting inflammation of the brain and nervous system. When these drugs were tried in humans, not only did they not help, but they actually made the MS worse. Unfortunately, optimistic animal research does not always translate into success in humans.”
Sadly, in the interests of selling newspapers and increasing page views, shares and advertising revenue, a dramatic and misleading headline has been used. Whilst this study is interesting, and we look forward to further work happening to follow up these results, the breakthrough treatment we’re all hoping for is still some way off.
If you want to read the original paper, it is available for free from the PLoS Biology website: https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.3000307
Photo by Anastasiia Ostapovych on Unsplash
