Mouse fetal stem cells mend mum's broken heart

Mouse fetal stem cells can travel from the placenta to heal their mother's damaged heart, US scientists have found. The discovery may explain why some women who suffer heart failure during or shortly after pregnancy recover faster, and offers hope for new treatment methods using human fetal stem cells.

'Our research shows that fetal stem cells play an important role in inducing maternal cardiac repair', said study leader Dr Hina Chaudhry from the Mount Sinai School of Medicine, New York. 'This is an exciting development that has far-reaching therapeutic potential'.

Dr Chaudhry's team mated female mice with males whose cells had been labelled with a green fluorescent protein, meaning about half of the embryos also produced the fluorescent protein. Researchers then caused a heart attack in pregnant females, and after examining their hearts, they found fluorescent fetal cells at the sites of tissue damage.

These cells had been reprogrammed to become blood vessel cells, smooth muscle cells or beating cardiomyocytes (a specialised type of heart muscle cell). Importantly, the cells did not travel to other undamaged organs.

The fetal cells were also capable of becoming beating heart cells when the environment was recreated in a culture dish, highlighting their potential as a new source of stem cells for repairing damaged hearts.

'Identifying an ideal stem cell type for cardiac regeneration has been a major challenge in heart disease research', explained Dr Chaudhry. 'Embryonic stem cells have shown potential but come with ethical concerns. We've shown that fetal cells derived from the placenta, which is discarded postpartum, have significant promise. This marks a significant step forward in cardiac regenerative medicine'.

It has been noted that women who suffer from a type of heart failure called peripartum cardiomyopathy during or shortly after pregnancy show better recovery rates than any other group of heart failure patients. This work could go some way to understanding why this is the case.

The findings could also explain why male fetal cells were previously found within the hearts of two women, who suffered from heart weakness, years after they had given birth to their sons.

The research was presented in Orlando, Florida at the American Heart Association's (AHA) Scientific Sessions 2011, and is published in the journal Circulation Research.