Got Heart Disease??? No Problem!!!

**neutral88** · January 15th, 2008, 04:23 PM

"?Gutsy' scientists grow heart in jar
Research is small step in building organs for patients
By JOSEPHINE MARCOTTY - (Minneapolis) Star Tribune
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. Then they infused it with living cardiac cells from newborn rats, which multiplied and grew into a fully functional heart "? a first in the field of tissue engineering.

"While it still sounds like science fiction, we've hopefully opened a new door in the notion that we can build these tissues and one day provide options for patients with end-stage disease,"? said Dr. Doris Taylor, director of the Center for Cardiovascular Repair at the University of Minnesota. "We're not there yet, but at least now we have another tool in our tool belt."?

She said the technique, which used nature's own matrix of chambers, valves and blood vessels, 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 bioengineer.

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. The National Institutes of Health has provided millions of dollars for tissue engineering, but so far researchers have had success with only a few types of human tissue "? primarily bladders, skin and blood vessels.

Although growing heart tissue holds the greatest therapeutic promise of all, it also 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.

About 5 million people live with heart failure, and about 550,000 new cases are diagnosed each year in the United States. About 50,000 die annually waiting for a heart donor.

Researchers have tried to grow cardiac patches in the lab to use in repairing damaged hearts. But in order to work, tissue patches must be quite thick, and researchers have not found a way to provide the growing tissue with enough oxygen. Hearts also are three-dimensional "? the cells need a scaffold to grow on that allows the cells to contract and do the mechanical work of a heart.

"Scaffolding is the challenge where we are doing most of our work,"? said Ratner, who is trying to build an artificial structure with the same kind of material used for contact lenses.

Taylor said 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.

"When you think about a steak, it's the gristle,"? she said. It provides both the blood-vessel system to deliver oxygen and the three-dimensional structure. The researchers provided the right medium by placing it in a glass chamber and giving it oxygen, nutrients and fluids to pump.

The Associated Press contributed.