Doubts cast on adult stem cell potential
The potential of adult stem cells to treat degenerative disease has been thrown into question by a new US study.
The ability of ‘one size fits all’ stem cells to mature into any kind of tissue has generated many promises for future treatments of conditions such as Parkinson’s and Alzheimer’s. Ethical dilemmas surrounding the use of embryonic stem cells have placed high expectations on research into the use of adult stem cells.
But in a paper published in Nature this week, a collaboration of researchers from the US, Spain and Germany warn scientists should exercise caution in using adult bone marrow to generate new cells in other tissues.
Clinical trials are already underway in which adult stem cells from bone marrow have been have been injected into heart muscle in an effort to stimulate the formation of new heart muscle cells after heart attack. This approach was adopted after bone marrow cells were observed to contribute at very low levels to other tissues.
However, the team has shown in new experiments with mice that rather than displaying the plasticity to make new cells in other tissues, the adult stem cells are just fusing with pre-existing cells. This erroneously gives the impression they are generating new cells, the scientists claim.
‘Our findings raise a red flag about going too fast to clinical trials based on the assumption that transdifferentiation is the mechanism by which stem cells give rise to other cell types’, Dr Arturo Alvarez-Buylla argues.
His colleague Dr Sean Morrison adds that the findings emphasise the importance of keeping the stem cell research options open: ‘Responsible stem cell researchers have argued all along that it was important for research to continue with both embryonic stem cells and adult stem cells’.
The team’s paper was published at the weekend in the online version of the journal Nature.
