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University of Minnesota researchers have created a beating heart in the laboratory.
By using a process called whole organ decellularization, scientists
from the University of Minnesota Center for Cardiovascular Repair grew
functioning heart tissue by taking dead rat and pig hearts and
reseeding them with a mixture of live cells. The research will be
published online in the January 13 issue of Nature Medicine.
“The idea would be to develop transplantable blood vessels or whole
organs that are made from your own cells,” said Doris Taylor, Ph.D.,
director of the Center for Cardiovascular Repair, Medtronic Bakken
professor of medicine and physiology, and principal investigator of the
Nearly 5 million people live with heart failure, and about 550,000
new cases are diagnosed each year in the United States. Approximately
50,000 United States patients die annually waiting for a donor heart.
While there have been advances in generating heart tissue in the
lab, creating an entire 3-dimensional scaffold that mimics the complex
cardiac architecture and intricacies, has always been a mystery, Taylor
It seems decellularization may be a solution – essentially using nature’s platform to create a bioartifical heart, she said.
Decellularization is the process of removing all of the cells from
an organ – in this case an animal cadaver heart – leaving only the
extracellular matrix, the framework between the cells, intact.
After successfully removing all of the cells from both rat and pig
hearts, researchers injected them with a mixture of progenitor cells
that came from neonatal or newborn rat hearts and placed the structure
in a sterile setting in the lab to grow.
The results were very promising, Taylor said. Four days after
seeding the decellularized heart scaffolds with the heart cells,
contractions were observed. Eight days later, the hearts were pumping.
“Take a section of this ‘new heart’ and slice it, and cells are back
in there,” Taylor said. “The cells have many of the markers we
associate with the heart and seem to know how to behave like heart
“We just took nature’s own building blocks to build a new organ,”
said Harald C. Ott, M.D., co-investigator of the study and a former
research associate in the center for cardiovascular repair, who now
works at Massachusetts General Hospital. “When we saw the first
contractions we were speechless.”
Researchers are optimistic this discovery could help increase the donor organ pool.
In general, the supply of donor organs is limited and once a heart
is transplanted, individuals face life-long immunosuppression, often
trading heart failure for high blood pressure, diabetes, and kidney
failure, Taylor said.
Researchers hope that the decellularization process could be used to
make new donor organs. Because a new heart could be filled with the
recipient’s cells, researchers hypothesize it’s much less likely to be
rejected by the body. And once placed in the recipient, in theory the
heart would be nourished, regulated, and regenerated similar to the
heart that it replaced.
“We used immature heart cells in this version, as a proof of
concept. We pretty much figured heart cells in a heart matrix had to
work,” Taylor said. “Going forward, our goal is to use a patient’s stem
cells to build a new heart.”
Although heart repair was the first goal during research,
decellularization shows promising potential to change how scientists
think about engineering organs, Taylor said. “It opens a door to this
notion that you can make any organ: kidney, liver, lung, pancreas – you
name it and we hope we can make it,” she said.
Source : University of Minnesota. January 2008.
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