Human organs can now be grown, one cell at a time

Luke Masella was born with spina bifida, and after 10 years it was getting the best of him.

The congenital disorder affects the development of the nerves and vertebrae along the spinal cord, and can result in paralysis, neurological complications and organ damage.

In Masella's case, his bladder was failing and he spent much of his early childhood in the hospital. He was plagued by aches and pains, and often was too tired and lethargic to get out of bed. Because his bladder didn't work properly, his kidneys were shutting down.

"I remember being really scared," said Masella, a native of Madison, Conn. "I thought I was going to die."

Masella was gravely ill and needed a new bladder. This was 2001, and conventional treatment would have been to use a portion of Masella's intestine to make a new bladder.

But because the intestine is designed to absorb nutrients and a bladder is designed to excrete, it's a risky procedure, especially with young patients who often develop kidney stones and cancer.

So Masella was referred to Dr. Anthony Atala, then at Children's Hospital Boston. Atala is a pioneer in regenerative medicine, a cutting-edge field of study in which a patient's own cells are used to grow healthy tissue and organs. He has been director of the Wake Forest Institute for Regenerative Medicine in North Carolina since 2004.

To engineer a new bladder for Masella, Atala took samples of muscle cells from his bladder and grew them in a Petri dish. Once he had grown enough, he attached the cells to a bladder-shaped framework or scaffolding he created using collagen, the primary biological material found in skin and connective tissue.

The biological structure was placed inside an incubator, where it continued to grow for two months.

"It's like cooking a layered cake," Atala said.

Finally, the engineered bladder was sutured to Masella's original bladder. The biodegradable scaffolding dissolved, and as the new bladder integrated with the body, it grew its own blood supply and nerves.

Masella soon made a full recovery and went on to captain his high school wrestling team. He's now a healthy 21-year-old junior at the University of Connecticut.

Masella was one of the country's first patients to receive a regenerated organ grown from his own cells. Atala has since performed similar procedures many times, growing and implanting everything from urethras and skin to cartilage.

Atala and his team at Wake Forest are now working on more than 30 replacement tissues and organs for future trials, including the kidney, liver and even the heart.

Part of this groundbreaking research includes a technique called "bioprinting." While it may sound like science fiction, Atala said that in the last decade great strides have been made with this technology, in which modified inkjet printers are used to create biological molds of organs.

Rather than ink, the jury-rigged printers spray cells and heat-sensitive gel that fuse together to form tissue and organs.

Atala said he's made a number of organs and tissue prototypes using this technique, but none that is suitable to be placed inside a human.

Nonetheless, as the technology continues to advance, it stands to revolutionize how science treats diseased and injured tissues and organs.

One potential application is bioprinting skin for soldiers with life-threatening burns. Using this still-developing technology, skin cells could one day be printed directly on the soldier's wound.

And because regenerative medicine uses a patient's own cells to create organs and tissue, it eliminates much of the risk that the patient's body will reject a donor organ.