Heart breakthrough hailed
Published: Tuesday, January 15, 2008 at 6:01 a.m.
Last Modified: Tuesday, January 15, 2008 at 12:00 a.m.
It sounds like a scene from a science-fiction thriller: a group of scientists gathered around a laboratory dish in which they'd grown a living, beating heart.
What was done
- Researchers removed all the cells from a dead rat heart.
- They retained the valves and outer structure to serve as scaffolding.
- Heart cells from newborn rats were injected into this framework.
- Within two weeks, the cells formed a new, beating heart.
The reality is that it has happened - with a rat heart - and was reported Sunday in the journal Nature Medicine by researchers at the University of Minnesota Center for Cardiovascular Repair.
The study, headed by Dr. Doris Taylor, has paved the way for one long-promised goal in regenerative medicine: to use stem cells to grow organs tailor-made for transplant.
"This isn't just a piece of cartilage that we're sticking back into a knee - this is a functional organ," said Dr. Chris Cogle of the University of Florida's Program in Stem Cell Biology and Regenerative Medicine. "It's very exciting."
Taylor said she followed a guiding principle of her laboratory in the study: "Give nature the tools and get out of the way."
In a telephone interview from her laboratory, she told the New York Times Monday the early success of her study "opens the door to this notion that you can make any organ - kidney, liver, lung, pancreas - you name it, and we hope we can make it."
Cogle, an assistant professor of medicine, said the study shows that the connective tissue of organs such as the heart is not just a tethering that keeps our body together, but something that gives cells information for how our organs are formed and how they function.
"It is a smart framework - more than just a scaffolding," he said.
The other component that made the study a success, in his view, is having the right cells to sit on top of this framework. The cells must be pliable and able to "listen" to instructions.
"If the framework says to become a blood vessel, the cell on top on the frame has to have the right software to turn into a blood vessel," he said.
One type of cell that has that plasticity is a stem cell, and it is the focus of regenerative medicine studies across the country.
At UF, for example, Cogle is working with Dr. Carl Pepine, chief of cardiovascular medicine, to test whether injecting stem cells directly into the heart will help restore blood flow by prompting new blood vessels to grow. Fifteen patients will take part in that clinical study at UF, which is one of 20 research sites across the country.
What differentiates that study from the Minnesota project may be largely a matter of scale - Taylor and her colleagues have succeeded in generating a whole, functional organ.
"It's not something I thought I'd ever be able to build in a dish," she said.
Cogle believes the results will revolutionize thinking about organ transplant. He points to kidney transplantation as a prime example.
"You only have one heart, but if a patient has one bad kidney, it could be removed, denuded of cells, bone marrow taken from the patient to reseed the framework, and you'd have everything you need for an autologous kidney transplant," Cogle said.
Chris Batich, a UF professor in materials science and engineering, is working on the kidney extracellular matrix - that "smart framework" Cogle described.
Working with UF colleagues, including Naohiro Terada in biomedical engineering and nephrologist Edward Ross, Batich's group has isolated rat kidneys and treated them to create a framework, then injected embryonic stem cells that multiplied and remained viable for up to two weeks.
"We don't have any function yet, but we are using the same approach (as Taylor's group)," Batich said.
Batich describes the work as beginning studies, with the long-range goal of organ reconstitution.
It will take a whole team to eventually reach that goal, Batich said, but reports like the heart study coming out of Minnesota make the process even more exciting.
Diane Chun can be reached at 352-374-5041 or firstname.lastname@example.org
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