Baby hearts need rhythm to develop correctly, a new study suggests, even before they have blood to pump. “We have discovered that mechanical forces are important when making baby hearts,” Mary Kathryn Sewell-Loftin, a Vanderbilt graduate student working with a team of Vanderbilt engineers, scientists and clinicians attempting to grow replacement heart valves from a patient’s own cells, said.
The team reported that they have taken a big step towards this goal by determining the mechanical forces generated by the rhythmic expansion and contraction of cardiac muscle cells play an active part in the initial stage of heart valve formation. A heart valve has two or three flaps, called leaflets that open and close to control the flow of blood through the heart. It is intricately designed to cycle two to three billion times throughout a person’s lifespan.
The researchers aimed to study how heart valves develop naturally so they could determine how to duplicate the process. To do this, they designed a series of experiments with chickens, whose hearts develop similar to that of the human heart. Most animal heart valves go through their cycle about 1 billion times throughout their life, but chicken and human heart valves develop in similar ways.
“The discovery that the deformations produced by the beating cardiac muscle cells are important provides an entirely new perspective on the process,” said Merryman, who directed the three-year study. The study was published in the journal Biomaterials.
In spring 2012, the Vanderbilt team announced that they had identified previously unknown genes and molecular pathways associated with the formation of heart valves per Medical News Today. Their latest experiment – examining the “mechanical forces” influencing heart valve formation – fills in the gaps in the team’s knowledge.
“The genetic study gave us the list of the basic parts – the hardware – required to build a heart valve and this latest study provides us with the information we need about the environment that is required,” says Prof. Joey Barnett, co-principal investigator on the project.