It was the Bee Gees that asked, “How can you mend a broken heart?” They didn't seem to have any idea.

Bioartificial hearts may one day be the answer to North America's donor shortage problem.

We now have an answer. After three years of research, Dr. Doris Taylor and her team at the Center for Cardiovascular Repair at the University of Minnesota announced Jan. 13, 2008 that they have devised a way to bring a dead heart back to life.

It’s a delicate process, but head researcher and director of the center Dr. Taylor says she foresees the "bioartificial heart" technology will be developed for human use in the future.

“Our first goal was proof of concept to convince ourselves we could get it to work,” she says.

Dr. Taylor's experiment used dead rat and pig hearts to conduct whole organ decellularization. Decellularization is the process of removing all cells from an organ, leaving only the exterior framework or “matrix” intact. In order to remove the cells, the scientists injected a detergent wash (like a soap and water mixture) into the dead heart to clean out all the inactive cells inside. The wash forced the internal cells to disintegrate, leaving the exterior “scaffold” in place.

“The scaffold can remain alive because it is a collagen structure and made of protein,” says Dr. Marc Ruel, a cardiac surgeon at the University of Ottawa Heart Institute who did not participate in the research.

Armed with a clean and empty heart structure, Dr. Taylor's team injected the shells with live heart cells before placing the structure into a sterile environment so it could grow.

Those cells multiplied. They mimicked the pattern of cell activity in living heart tissue, with certain cells pumping and others contracting. And after eight days, the reconstructed heart was beating.

Long shot, long way off

“It’s a nice study but it’s certainly not something that’s going to affect a patient’s life in the next five, ten, fifteen years,” says Dr. Ruel.

Dr. Ruel says he suspects the technology will take years to develop for human use, if at all. The heart created in the lab was beating at a rate 15 per cent of what it would during an embryonic stage, and at only two per cent of an adult heart.

"It's a long, long shot," he says.

But Dr. Taylor says her team is already gearing up to improve the weak heartbeat. The next step will be to add more cells to the structure and to determine the best lab environments. She says while getting the technology ready for humans may be years away, the promise of further experimentation is around the corner.

“There’s nothing saying we can’t work quickly to do the transplants (into rats). It’s just a matter of resources,” Dr. Taylor says.

Resources might be one of the biggest challenges in furthering the technology. Not only do the researchers need raw materials to create the hearts, they need equipment. The size and cost of the equipment grows as the experiments start to include larger animals, says Dr. Taylor. A machine that cost $50,000 for the rat heart experiment could cost 10 times more for a larger-scale operation, she says.

But Dr. Taylor says she’s confident this technology will be poked and prodded and polished enough that one day heart disease patients might choose to grow a bioartificial heart containing their own cells. Another choice, another option, another way to try and relieve some stress off the American donor pool.

The reality is, like our southern neighbours, Canada's organ donor pool is more like a wading pool. The number of people needing organ transplants far outweighs the number that actually receives one. In 2007 in Ontario, there were 1,676 people on the waiting list for all organ transplants, according to the province's Trillium Gift of Life Network. Only 531 received an organ.

If developed for human use, the bioartificial heart technology could provide more options to help relieve the donor shortage. Organs past their donor prime (anything older than four hours cannot be used for transplant) could serve as the scaffold to grow a bioartificial heart, says Dr. Taylor. The other option is to turn to animals like pigs that have organs similarly sized to humans.

“We already use pig valves for human transplantation. It’s not unreasonable to think about using pig tissue,” she says.

Scientists say they are hopeful the bioartificial heart technology will be developed for human use.

Dr. Taylor says she hopes the procedure, if developed for human use, will be able to minimize the risk of rejection and subsequent immunosuppression. According to the Heart and Stroke Foundation, immunosuppression results in parts of the immune system becoming useless. Sometimes this happens naturally, and other times, like in the case of organ donation, immunosuppression is induced with drugs to stop the immune system from rejecting the organ. Side effect: The drugs work on the whole immune system, so you're less likely to be able to battle colds and viruses.

But if bioartificial hearts become the new norm, immunosuppression would likely be less of an issue because the recipient would have an organ containing his or her own injected cells, Dr. Taylor says.

“We would use the stem cells to make the scaffold somewhat more invisible to the recipient. The hope would be that over time, as the cells in the new organ replace the proteins (in the scaffold), it would become completely your own,” she says. “But we don’t know that for sure. The prediction is that you might need (immunosuppression medication) for a while but not forever.”

Dr. Ruel points out that before bioartificial hearts are refined and approved for human use, bigger and better technology could become the new norm.

"The question is, is it going to be easier to recreate a heart from scratch or to optimize an existing machine . . . the answer is probably the latter," he says.

Heart transplants, however, are clearly not without their complications, says Dr. Taylor.

“One of the major problems with getting a heart transplant is you’re trading one disease for another, like high blood pressure. The hope is we could preclude that,” she says.