A study published in the journal Biomaterials last month suggests that for proper development, baby hearts need rhythmic expansion and contraction of cardiac muscle cells even prior to the formation of blood vessels.
“We have discovered that mechanical forces are important when making baby hearts,” said Mary Kathryn Sewell-Loftin.
She is a graduate from Vanderbilt working with a team of Vanderbilt engineers, scientists and clinicians attempting to grow replacement heart valves from a patient’s own cells.
Rhythm is a driving forec in the preliminary structuring of heart valves.
The heart forms as a plain U-shaped tube of tissue, containing three layers. Underneath the muscle there is a layer of “cardiac jelly,” and beneath that is a layer of endothelial cells that will convert into valvular interstitial cells (VICs).
A heart valve is a splendid device. It has two or three flaps, called leaflets. The leaflets open and close up to direct the flow of blood through the heart. Its design supports a cycle of two to three billion times in a person’s life span. However, heart valves are susceptible to damage due to diseases such as ageing, rheumatic fever and cancer, birth defects and heart attacks.
The researchers wanted to study how heart valves develop naturally so they can figure out how to replica the process.
Artificial valves at present exist, but they are made ready with plastic, so children born with innate heart defects must undergo multiple surgeries to have these substituted as they grow up.
“For the last 15 years, people have been trying to create a heart valve out of artificial tissue using brute-force engineering methods without any success,” says W. David Merryman, assistant professor of Biomedical Engineering at Vanderbilt University in Nashville, TN.
“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.
This initiative is part of a extensive program of development of artificial organs named the Systems-based Consortium for Organ Design and Engineering (SysCODE). It is National Institutes of Health “Roadmap” inventiveness to tempo the movement of scientific discoveries from the work surface to the bedside.
A typical procedure for observing the early stages of heart development is to haul out the heart of a chick – at the point when it is the size and shape of a comma on a printed page – and place it in a cell culture dish with collagen gel.
The Vanderbilt team has planned to work further with a stem cell researcher to bring into being their own endothelial cells, from which they expect they can produce human VICs. Once VICs are there, the researchers consider they should be competent to grow artificial human heart valves in a bioreactor.
