Scientists pinpoint a crucial event in heart development in the womb that could help identify children at risk of heart defects

9 June 2015        

Developing mouse heart shown in red and blue

Researchers we fund at University College London have worked out exactly how the developing heart forms its two major blood vessels. 

They hope to use this new understanding to help identify the genetic causes of congenital heart defects, making it easier to find the children that will need urgent surgery to save their lives after birth. 

The research team, led by Professor Christiana Ruhrberg and Professor Peter Scambler, has revealed in the 'Journal of Clinical Investigation' how cells in the developing heart force the heart’s one major vessel to split into two. 

The two new vessels become the pulmonary artery, which carries low-oxygen blood from the heart to the lungs to pick up more oxygen, and the pulmonary veins, which carry high-oxygen blood back to the heart so that it can be pumped around the body. 

Find out more about how your heart works.

In mice, the researchers were able to follow a group of cells, called neural crest cells, as they travel from the newly forming spinal cord into the developing heart. Once in the heart, they observed how these cells deliver the instructions that will lead to a bridge of dividing muscle that splits one heart vessel into two. If this ‘bridging process’ is disturbed in the womb, babies are born with heart defects that can prove fatal.

Heart defects are the most common form of congenital defect – around 12 children are born with a heart defect every day in the UK. One in ten of these children will not make it to school age.

Congenital heart defects can sometimes be fixed by surgery immediately after birth, or even while the baby is still in the womb.  But we still don’t understand the reasons why many of these defects occur. By identifying exactly how these genes tell the one major heart vessel to split into two, this research can help doctors work out who is at risk of heart defects, find the babies that need treatment and make sure that they have the best chance of survival. 

What's new?

Professor Christiana Ruhrberg who led the research, funded by the BHF, said “Researchers have been identifying the pieces of a puzzle - how the heart splits its one vessel into two - for many years, but our research shows how these pieces fit together. 

“With this new-found knowledge, we can give meaning to genetic testing - we can explain why a faulty gene leads to a heart defect. By identifying the important genes in these terrible, life-threatening conditions, we hope to help geneticists and doctors work out which families and unborn children are most at risk and intervene to help them as soon as possible.”

Calum Morris, 9 from Bristol, was born with a heart defect called truncus arteriosus, which is caused by this bridging process failing when he was in the womb. Calum was born with just one major blood vessel, which meant his heart wasn’t properly pumping oxygen-rich blood around his body. 

Professor Jeremy Pearson, our Associate Medical Director said: “Heart development is a very complicated process, made even more complex by the fact that tiny unexpected changes in the womb can lead to potentially fatal congenital heart defects. The exact reasons behind the many forms of congenital heart defects are still poorly understood and more research is urgently needed if we are to help the 12 babies born every day in the UK with a heart defect. 

BHF-funded research has contributed to the number of babies dying from congenital heart disease falling by 80 per cent over the last three decades but we must do more. 

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