Future Heart to Be Built on Demand

What if you could just order up a heart on demand? If getting a heart transplant were as easy as replacing a car part, patients waiting for heart transplants would be relieved.

We may be closer to creating a heart in a lab than you think.

Ever since the South African surgeon Christiaan Barnard performed the first heart transplant in 1967, the world has been intensely focused on the possibilities of someday making this a routine procedure.

The shortage of organs that could be transplanted is one of the crueler realities of modern medicine. Across the United States, more than 4,000 people are currently waiting for a heart to be donated to them, but only 2,300 of them will actually receive one, according to the United Network for Organ Sharing.

Given the organ shortage, Michael Sefton, director of the Institute of Biomaterials and Biomedical Engineering at the University of Toronto says "let's do something better than transplants." He suggested growing a heart in a laboratory from scratch.

"I was amazed that nobody laughed," Sefton says. "Or at least they didn't laugh in public."

The ultimate goal is to create what Sefton calls a "heart in the box," which is a transplantable heart that could be stored in hospitals, ready for a patient.

In fact, they have already begun to create a heart muscle, grown in a lab from mouse cells, pulsing on its own.

Growing Heart Valves by Hand

Piece by piece, teams of researchers worldwide are figuring out how to grow other body parts besides a heart, including not only muscle, but valves, arteries and nerve tissue.

Dr. John Mayer at Harvard Medical School is on the front lines, learning how to grow heart valves by hand. The key is to make a tiny polymer frame or mold on which the cells that would make a valve that can be made to grow in the right shape. Their first use could be to replace damaged valves in children.

"I think we're moving closer to actually having something that we would be able to offer patients within the next three to five years, I would hope," says Mayer. Sefton estimates the cost for creating a functioning heart for pre-clinical testing will be $5 billion.

Another researcher, Dr. Joseph Vacanti, who is based at Massachusetts General Hospital is tackling one of the most intricate parts of the problem. For the heart to get nourishment while it does its job, it needs to be laced with microscopic blood vessels. Vacanti has figured out how to grow them on frames, which are made the same way computer circuits are.

"But instead of making electrical circuitry that's required in miniaturization for computer chips, we're making vascular circuitry," says Vacanti.

Made to Order Valve

Someday, the scientists hope, there will be commercial labs where, if you need a new organ or just some replacement tissue, it can be grown to specifications.

"My colleagues cringe when I use this, but it becomes, you know, like fixing a car," says Sefton. "Replace the carburetor with a new one."

"The idea of doing this in 10 years is steadily becoming less and less ridiculous," he adds, "just ambitious and just exciting."

And if parts can be made to order, perhaps the agonizing wait for transplants will end.

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