The human heart begins to beat four weeks into pregnancy, which means that cardiac valve defects develop as early as four weeks. With congenital heart defects causing the majority of birth defect-related deaths, the recent discovery of a key regulatory gene involved in cardiac valve formation provides promise for researchers looking to intervene.
Heart valves are responsible for maintaining the regular flow and pressure of blood in and out of the heart’s chambers, the atria and ventricles. Structural problems with these valves prevent blood, packed with oxygen and nutrients, from reaching tissues all over the body, including in the brain and other organs.
From the University of Basel, in a study published in the journal Cell Reports, researchers discovered for the first time a heart defect in mouse embryos caused by a lack of a protein called HAND2. The gene coding for HAND2 was previously associated with cardiac valve formation, but now scientists are finally uncovering the molecular mechanisms and the network of genes controlled by HAND2 that are involved in the development of congenital defects.
With functional HAND2, cells contributing to cardiac valve precursors, called “cardiac cushions,” are rearranged and migrate away from the heart wall lining. Without HAND2, the cardiac cushions don’t properly develop into valves.
“Not only does this discovery advance our molecular knowledge of cardiac valve development, but it may also help to provide genetic diagnosis for patients that suffer from congenital heart malformations,” explained first author of the study Fréderic Laurent.
Heart valve replacement procedures are available and common for children born with heart valve defects. The future potential to create replacement valves from stem cells could make these procedures even more effective and long-lasting, and the study authors believe that their recent finding could help make this idea a reality: “The discovery that HAND2 is a key regulator of the cellular and gene regulatory processes underlying heart valve formation is a potential milestone in this direction.”
Source: University of Basel