Embryonic stem cells get all the publicity in stem cell research, good and bad. Their supporters see them as the future of regenerative medicine, producing all manner of new human tissues to treat degenerative diseases. Opponents – mainly from religious groups – hate the fact that they originate with the destruction of an embryo.
No treatment based on human embryonic stem cells has yet been tested on patients, though the US Food and Drug Administration recently told Geron that it could begin a clinical trial of embryonic stem cells to treat spinal injury. Meanwhile, as the UK national stem cell conference in Oxford heard today, universities are making good progress using adult stem cells, derived from the patients themselves, to repair bone and cartilage.
At Southampton University Richard Oreffo is leading a programme to fill holes or gaps in bones caused by accident or disease with a “living composite” material, made of stem cells extracted from the patient’s bone marrow mixed with a biocompatible scaffold.
Four patients have so far received transplants of living composite, says Prof Oreffo. Early signs are encouraging: the material is integrating well with the patients’ own bone and stimulating natural regrowth.
Meanwhile Alicia El Haj of Keele University is working on a 10-year clinical trial at Oswestry Orthopaedic Hospital, using adult stem cells to repair cartilage damaged in accidents. The patients’ stem cells are multiplied outside the body, before being injected back into injured joints.
Although the Oswestry trial uses stem cells on their own, Prof El Haj is also leading a more futuristic research project in which stem cells are linked to microscopic magnetic nanoparticles. “We can then use a magnet to move the stem cells around the body and control what they do there,” she says.
Magnetic control could be far more effective than simply injecting stem cells into the patient. The nanoparticle system has already produced new tissue growth in laboratory mice and is about to be tested in goats, ahead of clinical trials.
While adult stem cells are more readily available than embryonic stem cells – and pose no ethical problems – they are much less versatile. However Prof El Haj said techniques developed for adult stem cells, such as magnetic control, could be adapted to embryonic stem cells or the recently discovered “induced pluripotent stem cells” (which are made by reprogramming adult cells so that they revert to an embryonic state).
At present stem cell trials use one-off procedures developed by individual research teams. “We need to move away from bespoke therapy into standard procedures that can be used by [doctors] anywhere,” says Prof El Haj.
Although many scientists and patient groups are impatient for stem cell research to deliver clinical benefits more quickly, Prof Oreffo says it is important not to push ahead too fast: “The last thing we want is a case that goes wrong, because that would set the field back tremendously.”