Umbilical cord blood may help build new heart valves

Nov 10, 2008

Children with heart defects may someday receive perfectly-matched new heart valves built using stem cells from their umbilical cord blood, according to research presented at the American Heart Association's Scientific Sessions 2008.

When infants are born with malfunctioning heart valves that can't be surgically repaired, they rely on replacements from animal tissue, compatible human organ donations or artificial materials. These replacements are lifesaving, but don't grow and change shape as a child develops; so two or more surgeries may be needed to replace outgrown valves. The animal tissue may also stiffen over time as well and be less durable than a normal human valve. With artificial valves, children also must be treated with blood thinners.

"In our concept, if prenatal testing shows a heart defect, you could collect blood from the umbilical cord at birth, harvest the stem cells, and fabricate a heart valve that is ready when the baby needs it," said Ralf Sodian, M.D., lead author of the study and a cardiac surgeon at the University Hospital of Munich.

The tissue engineering of heart valves is still in its infancy, with various researchers investigating the possibility of using cells from blood, bone marrow or amniotic fluid.

In the study, the research team used stem cells (CD133+ cells) derived from umbilical cord blood. The cord blood was frozen to preserve it. After 12 weeks, the cells were seeded onto eight heart valve scaffolds constructed of a biodegradable material and then grown in a laboratory.

Afterwards, examination using electron microscopes revealed that the cells had grown into pores of the scaffolding and formed a tissue layer. Biochemical examination indicated that the cells had not only survived and grown, but had produced important elements of the "extracellular matrix," the portion of body tissue that functions outside of cells and is essential to tissue function and structure. Compared with human tissue from pulmonary heart valves, the tissue-engineered valves formed:

-- 77.9 percent as much collagen (the main protein in connective tissue);
-- 85 percent as much glycosaminoglycan, a carbohydrate important in connective tissue); and
-- 67 percent as much elastin (a protein in connective tissue)

Furthermore, using antibodies to detect various proteins, the researchers found the valves contained desmin (a protein in muscle cells), laminin (a protein in all internal organs), alpha-actin (a protein that helps muscle cells contract) and CD31, VWF and VE-cadherin (components of blood vessel linings).

"These markers all indicate that human cardiovascular tissue was grown in the lab," Sodian said.

Several important questions remain to be solved regarding tissue-engineered functional heart valves, including identifying the optimal scaffold material and learning how to condition the valves in the laboratory so they work properly after being implanted, Sodian said.

"Tissue engineering provides the prospect of an ideal heart valve substitute that lasts throughout the patient's lifetime and has the potential to grow with the recipient and to change shape as needed," he said.

Source: American Heart Association

Explore further: World–first human Hendra virus clinical trials begin

Related Stories

Language of gene switches unchanged across the evolution

Mar 17, 2015

The language used in the switches that turn genes on and off has remained the same across millions of years of evolution, according to a new study led by researchers at Karolinska Institutet in Sweden. The ...

Measuring the pulse of trees

Mar 16, 2015

I read many years ago that if you wanted a tree to recognise you, you would need to sit quietly at its base for a week. Very Zen!

Desmoplakin's tail gets the message

Mar 02, 2015

Cells control the adhesion protein desmoplakin by modifying the tail end of the protein, and this process goes awry in some patients with arrhythmogenic cardiomyopathy, according to a study in The Journal of ...

Recommended for you

What is campylobacter, and what are we doing about it?

2 hours ago

Campylobacters are spiral-shaped bacteria that often colonize the intestines of animals grown for food (as well as other animals)—and they can cause acute diarrheal disease (called campylobacteriosis) in ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.