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Researchers grow functional heart in a jar

MINNEAPOLIS – Researchers at the University of Minnesota have grown a beating heart in a jar.

They used detergents to strip a rat heart of its own cells, leaving behind a white, three-dimensional scaffolding of connective tissue. They then infused it with living cardiac cells from newborn rats, and those cells multiplied and grew into a fully functional heart – a first in the field of tissue engineering.

“We’ve figured out how to use nature’s own matrix – chambers, valves, blood vessels,” said Dr. Doris Taylor, the lead researcher and director of the university’s Center for Cardiovascular Repair. She said that the technique holds promise for growing human tissue to repair not only hearts but many other parts of the body. It might be possible, she said, to grow whole organs for patients who need a transplant.

Other tissue engineering scientists around the country said there are enormous obstacles to using the technique for people but described the work as exciting and a landmark.

“It’s gutsy. I am very impressed with her going right for the meat of it … and showing remarkable results,” said Dr. Buddy Ratner, a University of Washington bio-engineer.

The research was published online Sunday by Nature Medicine, a journal known for publishing cutting edge science.

Growing human tissue outside the body has been a medical Holy Grail for decades. Progress accelerated in recent years with the use of stem cells, special cells in embryos and adults that can be manipulated to grow into many kinds of tissue.

Growing heart tissue holds the greatest therapeutic promise of all, but it has proved the most difficult. The heart is a complex structure of chambers, valves, and thick muscled walls fed by an intricate system of blood vessels. And it doesn’t just contract; it twists, as if the muscle was wringing the blood out of the chambers and into the body.

Taylor said that one of the rules in her laboratory is “to give nature the tools and get out of the way.” That’s how she and her co-researchers came up with the idea of adopting a strategy that’s been used elsewhere for smaller parts of the body. They stripped a heart of its cells, leaving behind what’s called the extracellular matrix.

“The cells know they are in a heart and that they should act like a heart,” she said.


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