Stem cells shown to be safe for regenerative medicine

17 December 2015        

Heart muscle cells We now have the strongest evidence to date that human stem cells will develop normally once transplanted into an embryo thanks to research we helped to fund.

The findings, made by researchers at the University of Cambridge and published in the journal Cell Stem Cell, could have important implications for finding regenerative treatments for heart attack and heart failure.


The team were studying pluripotent stem cells - these are cells that can be transformed into any type of tissue in the body, including heart tissue. These stem cells could one day be used to grow new heart muscle and repair the currently irreversible damage caused by a heart attack.

Why might stem cells not be safe?

Despite their promise, some scientists have been concerned that stem cells might not properly incorporate into the body and potentially cause tumours to develop. This study shows that this will not happen and that stem cells are likely to be safe for use in regenerative medicine.

Professor Roger Pedersen from the Anne McLaren Laboratory for Regenerative Medicine at the University of Cambridge, who led the research says: "Our study provides strong evidence to suggest that human stem cells will develop in a normal – and importantly, safe – way. This could be the news that the field of regenerative medicine has been waiting for."

How did the researchers make this discovery?

To test whether stem cells are incorporating well in the body, they are transplanted into an early-stage embryo and then studied. This cannot be carried out ethically using a human embryo so researchers use embryos from mice.

The stem cells are put into the mouse embryo at a very early stage, shortly after fertilisation and then the researchers assess how the cells contribute to the development of the different body tissues. The Cambridge researchers, including Victoria Mascetti, a PhD student we fund, have successfully got stem cells to incorporate into embryos for the first time. They managed to do this by ensuring the stem cells were developed to a stage that matched the embryo's development.

A step closer to mending broken hearts

Our Associate Medical Director, Professor Jeremy Pearson, said: "These results substantially strengthen the view that induced pluripotent stem cells from adult tissue are suitable for use in regenerative medicine – for example in attempts to repair damaged heart muscle after a heart attack.

"The Cambridge team has shown definitively that when stem cells are introduced into early mouse embryos under the right conditions, they multiply and contribute in the correct way to all the cell types that are formed as the embryo develops."

We're funding an ambitious programme of regenerative medicine research thanks to generous donations to our Mending Broken Hearts Appeal.

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