Deafness Research UK is funding a new research programme that will be the first to try and develop a cure for deafness using stem cells taken from umbilical cord blood or bone marrow.
Wednesday 13 December 2006 - This three-year project will be 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 will be 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.
The lead researcher, Dr Marcelo Rivolta said, "We're really excited about these new lines of cells. They don't have the same ethical issues that surround embryonic stem cells but, more importantly, they could be a readily available source of stem cells for a medical therapy for deaf or hard of hearing people.
"They have the big advantage that it should theoretically be possible to take stem cells from a patient, grow them in culture, and then transplant them back into the patient without fear that they would be attacked by the body's immune system. For example, everyone could have their umbilical-cord blood frozen or stored at birth and use it as a handy source of personal stem cells for medical therapies when we become old or ill."
Stem cells interest scientists because, unlike most adult cells in the body, they retain the potential to turn into many different types of cell. If we can learn to control them, they can be used as a 'repair kit' to replace damaged organs with healthy tissue.
Stem cells exist in almost every tissue of the body but most can only turn into the other cells within the same tissue (heart stem cells cannot turn into working liver cells for example). Until recently, scientists believed that the embryo was the only source of stem cells with the ability to become almost any type of tissue - so-called "pluripotent" stem cells. However, it has now been shown that stem cells from bone marrow or the blood in the umbilical cord (normally just thrown away after birth) also have this ability.
Dr Rivolta, the only scientist in the UK working on a stem cell cure for deafness, has 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 them and transform them into an electrical signal, and the 'nerve cells' which act as a link between the hair cells and the brain and carry the electrical signal that tells the brain what sounds are being heard. With age-related deafness, our hair cells gradually die off and, because they cannot be replaced, as we get older, the connection with the nerve is also lost and the nerves themselves degenerate.
Dr Rivolta's research opens up the possibility of growing both hair cells and nerves from stem cells and has been very promising.
"So far, we've learnt how to extract and grow them easily, how to maintain and look after them, and how to control their environment so that they become inner ear nerve cells or hair cells," he says. "We think we've successfully created a "recipe book" for the growing conditions necessary to get other sources of stem cells to become inner ear cells."
Dr Rivolta believes that the two new sources of cells could have distinct advantages.
"The most versatile source of stem cells comes from IVF-created embryos that are typically just 5 or 6 days old. Although these are just a microscopic ball of cells, many people argue that they have the potential to become a human and so believe that experimenting on them is morally wrong. There are practical problems with embryonic stem cells too - the source tissue is not very plentiful and the cells can be difficult to obtain and grow.
"This new grant is important because it will enable us to use our 'recipe book' to try and get the new stem cell lines to turn into hair cells and nerve cells in the laboratory. If successful, we've then got another series of tasks to learn how to introduce them into the human ear and still get them to do what we want."
There is still a long way to go, but if Dr Rivolta can control these new lines of stem cell, and can develop successful techniques for getting them to develop in the ear of a deaf patient, then a medical therapy for deafness could, at long last, become a reality.
Taken from www.deafnessresearch.org.uk/First+blood+and+bone+stem+cell+research+on+deafness+3261.twl
