Brussels, 26 Jan 2004
Headlines takes a closer look at 'Bionic Ear', the EU-backed project whose revolutionary discoveries about hair cell regeneration in the inner ear could one day mean a cure for deafness, a disability affecting one in ten people.
With a title like 'Bionic Ear', one could be forgiven for thinking that this team of European researchers had built a super ear to be attached to Steve Austin, the king of 1970s science fiction television, rather than a biological means of repairing the hair cells in the inner ear which can be damaged by noise, infections or simply ageing.
Deafness of this nature affects a staggering 10% of the 'active' population – more than 30% among the elderly – and had previously been considered an irreversible condition. With the discovery that new stem cell growth in the inner ear is possible in adult mice, millions of people worldwide may one day have their hearing repair itself. But there is still much work to be done before this 'self-repairing' mechanism can be translated from a positive result in animals to a cure for humans.
"Our consortium's discovery of 'proliferative' new hair cells in the inner ear is exciting because it is the first time this sort of regeneration has shown [to] take place in higher vertebrates," Dr Dongguang Wei of Karolinska Institutet's (KI) centre of hearing and communication research in Sweden told Headlines. "The results are certainly positive, but there is still a long way to go before a cure for deafness can be announced," he cautioned.
In a statement to the press, Research Commissioner Philippe Busquin hailed the success of the EU project, which shows that Europe is capable of producing cutting-edge research through effective cross-border collaboration. "[The] findings of the Bionic Ear project are very promising," he said. But he echoed Dr Wei in stressing that more research is needed to prove that these hair cells could efficiently replace damaged elements of the human ear.
Sounds of silence
Partners in the Bionic Ear project include researchers from universities in France, Sweden, Italy and Switzerland. In particular, research into the inner ear's hair cells was carried out by Dr Eric Scarfone of France's Centre National de la Recherche Scientifique (CNRS), who is also coordinator of the project, and Dr Mats Ulfendahl of Stockholm's KI. The expertise on adult stem cells came from KI's Professor Jonas Frisén.
For the European Commission, which contributed €1.53 million towards the project's total budget of €2.77 million, the decision by the American Society for Cell Biology (ASCB) to feature Bionic Ear in its annual conference, held last month, is recognition that Europe is at the forefront in this field of research.
Representing Bionic Ear at ASCB's 43rd annual meeting in San Francisco, Dr Wei was overwhelmed by the level of interest their work generated. "It was very exciting to be there and answer the many questions," he said after the event. "Specialists in stem cell biology at the meeting gave us further ideas on how to test the functions of the newly-generated hair cells," he said. However, a few in San Francisco were sceptical about how the team would follow up its discoveries.
Dr Scarfone explained that the consortium's findings to date – that neurons in the inner ear can re-establish functional contact with sensory hair cells in vitro – indicate that a re-connection with the brain is possible. "In conditions similar to the ones producing adult neural stem cells, we have been able to generate new hair cells, in vitro, from sensory tissues of mice's inner ear – tissues that, until now, were believed to have no, or very limited, regenerative properties when damaged," he said.
In the remaining year of the four-year project, the team will feed its results into what Dr Scarfone calls an 'experimental bioelectrode', which is an electrode containing cells able to stimulate and attract the neurons. This phase of the project will be tested in Stockholm on an animal deafness model, proving one way or the other whether deaf people may one day be able to hear again.