Doctors have created the first living artificial heart in a development that could herald the end of organ shortages.

In an unprecedented feat, researchers “refurbished” a dead heart so that it can beat again.

The breakthrough could overcome the shortage of replacement hearts and other organs and do away with the need for anti-rejection drugs, according to an American team.

Ultimately, scientists hope to use patients’ own stem cells to manufacture new hearts.

The “bioartificial heart” is described today in the journal Nature Medicine by University of Minnesota researchers in what could pave the way to a treatment for 22 million people worldwide who live with heart problems.

The team took a whole heart from a rat and removed cells from it. Then, with the resulting architecture, chambers, valves, and the blood vessels intact, repopulated the structure with stem cells.

After four days, contractions were observed and by Day 8, the cells had grown into pumping heart-like organs.

“We just took nature’s own building blocks to build a new organ,” Dr. Harald Ott, a co-investigator who now works at Massachusetts General Hospital, said. “When we saw the first contractions, we were speechless.”

The work has huge implications: “The idea would be to develop transplantable blood vessels or whole organs that are made from your own cells,” the director of the Center for Cardiovascular Repair in Minnesota and the study’s principal investigator, Doris Taylor, said. The method could be used to grow livers, kidneys, lungs, and pancreases, indeed “virtually any organ with a blood supply.” She told the Daily Telegraph that although “years away” from use in hospitals, she is ready to grow a human heart, though the cost is prohibitive.

In general, the supply of donor organs is limited, and once a heart is transplanted, individuals face lifelong hardships, forced to take drugs to prevent organ rejection and often trading their heart problems for high blood pressure, diabetes, and kidney failure over the long term.

Because a heart created by this method could be filled with the recipient’s own stem cells, the parents of other types, it is thought 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. Our goal is to use a patient’s stem cells to build a new heart,” Ms. Taylor said.

As for the source of the cells from a heart patient, she said: “From muscle, bone marrow, or heart; depending on where the science leads us.”

According to figures from U.K. Transplant, 155 people had their lives saved or transformed by a heart transplant last year, though 28 died while on the waiting list. Currently, 81 people are waiting for heart transplants. A U.K. Transplant spokesman said: “These developments offer long-term hope and long may they continue, but the real problem now is a desperate shortage of donated hearts.”

How the Technical Problems Were Overcome

While recent advances have been made in growing heart tissue in the lab, the problem has been how to create a framework that mimics the architecture and complex structures of the body’s primary pump. That is why Doris Taylor and her team resorted to removing all the cells from an organ with detergent.

The researchers then injected rat hearts with a mixture of immature cells from newborn rat hearts and placed the structure in a sterile chamber in the lab to grow. The results were very promising, Ms. Taylor said. Four days after seeding the “decellularized” heart scaffolds with cells, contractions were observed. Eight days after that, the hearts were pumping, albeit at only 2% of the efficiency of an adult heart.