Using stem cells to develop a cure for deafness
Deafness Research UK is funding a research programme that is the first to try to develop a cure for deafness using stem cells taken from umbilical cord blood or bone marrow.
[Project Grant, 2006-2009]
This three-year project is based in the Centre for Stem Cell Biology at the University of Sheffield and has been made possible by a £126,000 charitable donation from GlaxoSmithKline (GSK).
It is the first research to use these promising new lines of stem cells, which are less controversial than stem cells derived from human embryos, in the search for a cure for deafness.
Dr Marcelo Rivolta and colleagues have been studying stem cells taken from the inner ear of human foetuses, trying to understand the journey that these stem cells take to become a fully functioning, specialised cell of the inner ear.
Two of the most important types of cell in the inner ear are the 'hair’ cells – which detect sounds, amplify and transform them into an electrical signal – and the neurons which form the auditory nerve and carry the electrical signal from the hair cells onward to the brain. With age-related deafness, our hair cells gradually die off and, because they cannot be replaced, the connection with the nerve is lost and the nerves themselves degenerate.
Dr Rivolta's research explores the possibility of growing new hair cells and nerves from stem cells and so far has been very promising. In the first part of the project the team learned how to extract and grow the cells and to control their environment.
Having coerced bone marrow stem cells into producing hair cell precursors and demonstrated that these ‘progenitors’ can go on to become hair cells and neurons, the team will go on to explore the potential of these cell types in vivo (in a living system). Bone marrow-derived ear progenitors will be transplanted into deafened animal ‘models’ – animals such as mice that have ears similar enough to humans to allow new treatments to be tried and tested before applying the technique to humans – and their ears studied to see how the cells have integrated and whether lost function is recovered.
The proof of concept developed so far, that human bone marrow stem cells can become hair cells and neurons in vitro (in a laboratory dish) provides a platform for the development of a novel kind of therapy for people with hearing loss. In addition, these cells could also be used for screening drugs before human clinical trials for other medicines, to see if they can damage cells in the inner ear.
