Selected from a field of 1340 candidates, the project was placed on a short list of top class research that was presented at the annual meeting of the American Society for Cell Biology (ASCB) in San Francisco on 12 December, 2003.
Commenting on the project, EU Research Commissioner Philippe Busquin stated: "Every year, one European out of ten becomes deaf due to inner ear damage. This can be avoided, and the findings of the Bionic Ear project are very promising. However, more research is needed to prove that these newly differentiated hair cells could efficiently replace damaged elements of the human inner ear. If existing self-repair mechanisms could be enhanced or damaged hair cells be repaired with the help of adult stem cells, we could greatly contribute to the fight against hearing and balance impairments that severely disable so many people. The recognition of the potential of this research by the United States and the international scientific community demonstrates that we are at the forefront in this and other scientific fields."
Two of the project's partners, the Université de Montpellier II in France and Stockholm's Karolinska Institute in Sweden, have been working on the replacement of damaged sensory hair cells and their connecting neurons. The other partners are the Institute of Neuroscience of the Centro Nazionale Ricerche (CNR) in Milan, Italy, and the Ecole Polytechnique Fédérale de Lausanne, Switzerland.
The research on the sensory hair-cell part of Bionic Ear was carried out by Dr. Eric Scarfone's CNRS laboratory at the Université de Montpellier II and by Dr. Mats Ulfendahl at the Karolinska Institute in Stockholm. They have identified and isolated adult stem cells from vestibular sensory epithelia (VSE) in mice, which could be differentiated into new sensory hair cells. However, more research is needed, they say, to prove that these newly differentiated hair cells could efficiently replace damaged elements of the human inner ear.
The successful identification of stem cells in the inner ear of mice marks a new milestone in this project, which runs until the end of 2004. Together, these results demonstrate the potential for self-repair of the adult mammalian inner ear. The laboratory of Professor Jonas Frisén, also at the Karolinska Institute, is bringing its expertise on adult stem cells to this part of the project, which also comprises three other European laboratories.
It had previously been thought that sensory hair cells and their connecting neurons could not be replaced. However, growing reports on novel stem cell populations in the central nervous system prompted researchers on the Bionic Ear project to look for stem cells in the inner ears of adult mice. The successful identification of these stem cells has gained widespread interest, leading the project partners to highlight work that they have already done on turning this and other knowledge into therapeutic applications.
In a promising development, the project partners have combined cell therapy, encapsulation in a three-dimensional polymer matrix of genetically engineered cells, and cochlear implants, an electronic device that directly stimulates the sensory neurons of the inner ear, in an animal model of pathological deafness. Their work indicates that electronic stimulation of cells in the inner ear could also help to tackle deafness.
The finding of a regenerative potential of adult mammalian inner ear hair cells and of their connections to the brain opens up a new, significant possibility for rehabilitation of sensory handicap linked to peripheral inner ear damage: the stimulation of existing self repair mechanisms. Much is left to learn about the factors that trigger and instruct these mechanisms before they can be put into practical use, and this is bound to become a major line of study.
The four year Bionic Ear project was allocated 1,53 million euro out of a total budget of 2,77 million euro under the Quality of Life priority of the European Union's Fifth Framework Programme, and was presented by representatives of the European Commission at the ASCB meeting in San Francisco.