Adult Stem Cells Don’t Repair Heart
Bone marrow stem cells do not form cardiomyocytes in mice after acute myocardial injury.
Tuesday, 27 April 2004
Recent studies have suggested that bone marrow cells might possess an ability to extensively regenerate cardiomyocytes through transdifferentiation. In most cases, the reported efficiency of such plasticity has been rather low and, at least in some instances, is a consequence of cell fusion instead and not true transdifferentiation. However, bone marrow–derived cells are already being used in a number of clinical trials on humans, even though the exact identity and fate of these cells in infarcted myocardium have not yet been investigated in detail.
Now a group from Lund Strategic Research Center for Stem Cell Biology and Cell Therapy, Sweden, have shown that although the hematopoietic stem cells engraft and grow in the damaged myocardium, they do not form any new cardiomyocytes. The few ‘bone marrow–derived cardiomyocytes’ that could be observed in areas outside the injured tissue was exclusively due to cell fusion and not formation of new myocytes from the injected stem cells.
"The experimental basis for clinical trials on humans with bone marrow derived stem cells is now gone", professor Sten-Eirik Jacobsen at the Stem Cell Center in Lund said in an interview with the Swedish newspaper Dagens Nyheter.
He has spent the last two years investigating this issue after getting a $2 million dollar grant from the Swedish Research Council.
He still think these studies have been important, so that the true value of adult stem cells can be checked.
"Our studies also show that it was completely wrong not to investigate embryonic stem cells because adult stem cells might work," Sten-Eirik Jacobsen said.
Adult stem cells are still important to study, but then how they might be able to repair the specific organs and tissues they originate from. Take bone marrow cells e.g. for treating leukaemia that already have a long history of success. Similar, one can hope that stem cells from the brain can be touted to grow and repair injuries in the brain, and heart stem cells – if they exists – can be used for mending the heart.
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