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Doubt cast on adult stem cell therapies

10 May 2004
By BioNews
Appeared in BioNews 257

A new US study calls into question the existence of adult stem cells capable of transforming into insulin-producing pancreatic cells. Previous research in mice has suggested that such cells could be used to develop new treatments for diabetes. But the new study, carried out by scientists at Harvard University in Massachusetts, casts doubt on this idea. Their findings, published in Nature, show that new insulin-producing 'beta' cells arise from existing beta cells, rather than from stem cells. The discovery could pave the way for new treatments for the disease, and also emphasizes the importance of research into therapies based on embryo stem cells (ES cells) .

People with diabetes either do not produce enough insulin, or do not respond to the hormone's effects. Researchers are hoping to develop new treatments for this disorder by transplanting new, insulin-producing 'beta' cells into the pancreas. Previous work suggested that adult stem cells from the pancreas, spleen and bone marrow could transform into new pancreatic beta cells. But according to team leader Douglas Melton, the new study 'provides no evidence whatsoever for the existence of an adult pancreatic stem cell'.

The researchers developed a new 'tracking system' to see where new beta cells came from in normal mice with pancreas damage. They found that older beta cells themselves produced new cells, and that no stem cells were involved. Future diabetes research should focus on ways of getting these cells to produce enough new beta cells to treat the disease, the researchers say. But for people who have no beta cells left, the only source of new cells may be human ES cells. ES cells are the body's master cells, capable of growing into any type of body tissue.

Another study, published last week in Nature Medicine, has found little evidence that adult bone marrow stem cells can grow into heart cells, despite hopes that they could be used to treat damaged heart muscle. Researchers at Lund University in Sweden have found that bone marrow cells transplanted into hearts retain their 'blood cell' identity. However, they also found evidence of 'cell fusion' between some heart cells and transplanted bone marrow cells. This could explain the initial promising studies, say the scientists - several preliminary human trials have shown that bone marrow transplants can benefit heart failure patients.

The Swedish researchers ask whether current large scale trials should continue, since although there are 'some indications' that bone marrow transplants can heal damaged heart muscle, the underlying mechanism remains an open question. Many scientists are hoping to use adult stem cells to develop new therapies for a wide range of diseases, especially in countries where ES cell research is not permitted.

Diabetes Research Fuels Embryo Stem Cell Debate
The Washington Post |  6 May 2004
Discovery shifts focus on diabetes
The Boston Globe |  6 May 2004
Medical News Today |  6 May 2004
28 January 2008 - by Dr Karen Devine 
Researchers this week have reported that the much debated and 'elusive' insulin-producing stem cells really do exist in the pancreas. Despite scepticism over their actual existence, stem cells that can produce beta cells were found within the pancreas of adult mice during a study at the Diabetes...
25 September 2006 - by Dr Jess Buxton 
Three new studies published in the New England Journal of Medicine (NEJM) reveal contradictory results following the use of bone marrow-derived stem cells to treat heart attack patients. Two of reports found that injections of a patient's own bone marrow cells can improve heart function after...
2 May 2006 - by BioNews 
A team of US scientists has managed to successfully treat mice with symptoms of a genetic kidney disease, using bone marrow stem cells. The researchers, based at the Beth Israel Deaconess Medical Center, transplanted stem cells into animals affected by Alport syndrome, and saw a significant improvement in their condition...
3 March 2006 - by BioNews 
One form of stem cell therapy for heart attack patients appears to have little effect, German researchers report. The team, based at the German Heart Centre in Munich, carried out the largest trial designed to test the therapy to date. The results, published in the Journal of the American Medical...
13 October 2005 - by BioNews 
Doctors based at Barts and the London NHS Trust have launched a trial to test if heart damage can be effectively treated using stem cells taken from a patient's own bone marrow. The study will involve 700 patients, and will look at three different types of heart damage. The trial...
29 April 2004 - by BioNews 
Patients with heart failure could one day be treated with injections of their own stem cells, according to new US trials that provide the 'first convincing evidence' that such an approach might work. Previous studies have produced conflicting results, and some researchers have questioned whether stem cell therapies for failing...
25 March 2004 - by BioNews 
Two new studies have cast further doubt on the ability of blood stem cells to turn into heart cells, even though several clinical trials based on this promising new treatment are currently underway. Researchers at Stanford University, California, and the University of Washington in Seattle have failed to duplicate the...
8 March 2004 - by BioNews 
The use of blood stem cells to treat heart attack patients shows promise, but can lead to complications, South Korean researchers say. A new study published in the Lancet shows that although the experimental treatment can help repair damaged heart tissue, it also causes side effects in many patients. As...
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