Dr Huseyin Mehmet, Imperial College London
Part of the show Stem Cells & Stem Cell Therapy
Huseyin - My background is in brain development and especially trying to understand brain damage in premature babies. As doctors are becoming better at saving premature babies, our work is becoming more important. The more babies that survive, the bigger the pool of patients we need to treat. Once babies are born, there are a large number of cells in the brain which are already dead. We can't do much to help after the damage has been done. Our team became interested in replacing those damaged cells before they die, which is how we got into stem cells. We are very interested in using stem cells to help replace the cells lost in things like cerebral palsy. There's a lot of confusion in this field. I want to talk about exactly what the situation really is and take away some of the media hype. I also want to talk about where we might be going with stem cells and what the real prospects are for the future.
Chris - It may be possible to use these cells clinically. What are you doing to try and help people with cerebral palsy?
Huseyin - I'm a firm believer that there should be a good basis of scientific knowledge before clinical testing. There are many patients who are willing to take the risk of trying out treatments, but I think it's important to understand what's happening at the mechanistic level first. At the moment, we are trying to bring stem cells to the stage when we can differentiate them into tissues. If we understand this, then maybe we can persuade the patients' cells to do it. If we can make our own stem cells change into the tissues we want, there won't be any moral or ethical problems.
Chris - What is the difference between adult and embryonic stem cells?
Huseyin - The classic examples of non-embryonic stem cells are those isolated from bone marrow and neural cells from the brain. Some of these non - embryonic stem cells are already being used successfully today. Some blood stem cells are isolated from the bone marrow and put back into leukaemia patients after they've undergone their chemotherapy and radiotherapy. This repopulates the blood of the patient. This shows that there are clinical uses for them. However, the debate at the moment is whether they really have the same plasticity as embryonic stem cells. By that, I mean whether they have the breadth of potential to turn into all the other tissues. If we take stem cells from the bone marrow, they might only be able to produce cells that would normally arise in the bone marrow. Similarly, stem cells from the brain might only be able to turn into nerve cells. Some people have claimed to take brain stem cells and make them into muscle cells, but in my opinion this is very early days and highly controversial. However, if it is true, it will be very exciting.