Making a big breakthrough, researchers have uncovered why a foetal blood vessel can fail to close shortly after birth, causing serious health problems.

A German team showed that if the ductus arteriosus fails to close babies develop high blood pressure in the lungs and heart failure. Researchers at Munich’s Technischen University found that platelets, cells in the blood which form clots, play a key role in closing the vessel. The ductus arteriosus is a short vessel, which connects the pulmonary artery to the aorta, allowing most of the blood from the right ventricle of the heart to bypass the foetus’s fluid-filled lungs.

This protects the lungs from being overworked and allows the left ventricle of the heart to strengthen. However, once development is complete, the vessel’s work is done and it usually closes in the hours after birth, but researchers do not know how this process takes place.

In fact, sometimes it does not happen, causing a condition known as patent ductus arteriosus, which is a particular risk in premature babies with a low birth weight. If left uncorrected, this can lead to a build up of pressure in the blood vessels of the lung, which can trigger shortness of breath and dizziness. Ultimately, it can lead to irregular heart rhythms and congestive heart failure. In the study on mice, researchers found that platelets congregate at the ductus arteriosus during closure, promoting the formation of a clot as the vessel contracts. They showed that in mice with defective platelet function, the ductus arteriosus failed to close, which resulted in a condition similar to that found in the human disease- increased blood flow in the lung and excessive growth of the right ventricle of the heart. The researchers also showed, in a clinical study in premature babies that not having enough platelets in the blood was associated with a failure of the ductus arteriosus to close. “Our study might lead to a change of the current treatment strategies to prevent failure of ductus arteriosus closure, particularly in preterm newborns with low platelet counts,” the BBC quoted lead researcher Dr. Steffen Massberg as saying.

“It is conceivable that transfusion of platelets reduces the risk of ductus arteriosus patency (lack of closure) in preterm newborns with low platelet count,” added Massberg.

“This breakthrough is really promising as a better understanding of how the ductus arteriosus closes just after birth could help the treatment of very vulnerable babies, and potentially save lives,” said professor Jeremy Pearson, of the British Heart Foundation.

The study appears in the journal Nature Medicine.

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