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Chapter3

THE BODY SHOP

by Charles Hirschberg

from Lfie magazine

I believe I can build a human liver,” proclaims an exhausted Dr.

Joseph Vacanti, collapsing into his office chair at Children’s Hospital in Boston.

There’s something disquieting about hearing a doctor say such a thing. One can’t help thinking of the ghastly monster created by Dr.

Frankenstein, with its translucent yellow skin, shriveled face and black misshapen lips.

But Dr. Vacanti is no Dr. Frankenstein. Still in his scrubs, he has just come from the operating room where he performed lifesaving surgery on an infant. His body is spent; but his eyes flash with energy as he talks about his dreams. “It has never seemed like science fiction to me,” says Vacanti, a professor of surgery at Harvard Medical School and Massachusetts General Hospital. “My professional goal is to solve the problem of vital organs shortage.” More than 50,000 Americans are currently in need of organ transplant, and 4,000 of them are likely to die before a donor’3 is located. Vacanti’s solution is simple: Instead of replacing a faltering organ with one harvested from someone else, why not take a few healthy cells from the sick person and grow him or her a new one’? Such an organ would probably work better, too, since the body is less likely to reject tissue made of its own genetic material.

It sounds too good to be true. But it’s beginning to look like it just might work. And if it does, tissue regeneration could revolutionize the practice of medicine.

Apothecaries have experimented with tissue replacement for

centuries: As early as the sixth century B.C., Hindu surgeons began using arm skin to repair mangled noses. It wasn’t until the late 1970s that John Burke of Massachusetts General and Ioannis Yannas of the Massachusetts Institute of Technology succeeded in growing skin in a laboratory. Recently, several brands of artificial skin have been approved by the Food and Drug Administration for treatment of

ulcers and severe burns.

Still, as an organized field of inquiry, with an international professional society and a journal to report its progress, the science of tissue engineering has been around for little more than a decade.

There is quite a difference between growing a relatively simple organ such as skin and growing a complex one like a liver. For the liver is a congeries of many different types of tissues, all of which work together to accomplish a host of complicated tasks. “When I started trying to do this,” says Vacanti, 49, the son of a Nebraska dental surgeon, “a lot of people thought I was crazy. Some still think so.’ Not John and Debra McCormack of Norwood, Massachusetts.

Regardless of whether Vacanti succeeds in building a liver, he has already made a tremendous difference in the life of their 17-year-old son, Sean.

“When Sean was born, I was terrified,” Debra recalls. The boy

suffered from a rare condition called Poland’s syndrome. A large portion of his chest wall was either missing or deformed. His heart was healthy enough, but it lay unusually far to the right and was so completely unprotected by bone or muscle that it could be seen beating through his skin. Nevertheless, Sean grew to be a tough, resilient kid and a fine athlete. “My life never revolved around Poland’s syndrome,” he says. But he was embarrassed by his sunken chest and refused to take his shirt off in public—a problem, his parents knew, that could have increasingly serious implications as he grew older. What’s more, it was often a torment to watch Sean play baseball, talented pitcher though he was. His parents still. wince remembering the day he was hit by a line drive just inches from his exposed heart. Sean shook off the sting and proceeded to Win the game, but by this time both he and his parents were anxious to see what could be done about his condition.

That’s what brought them to Children’s Hospital.

Surgeon Dennis Lund first proposed tissue engineering in 1993.

“I’d worked with Dr. Vacanti for years,” Lund says, “and I explained to Sean and his father that we had a brand new technology in the laboratory. It had never been used in humans before, but I thought it would be completely safe because we would be using Sean’s own

tissue.” It took a long time for the McCormacks to fully comprehend what was being suggested. (“The first thing we did,” recalls John McCormack, “was go to the dictionary and look up the word protocol”—which turned out to be governmentese for experiment.) But after much study and many questions, they got the basic idea: Surgeons would open up Sean’s chest and extract a piece of

unneeded cartilageg from his malformed sternum.9 Next, a disk about the size of a doorknob made of a specially designed polymer“) would be fashioned to fill the hole in the boy’s chest. Then, in Vacanti’s laboratory, Sean’s cartilage cells would be dropped like seeds onto the disk and nourished in a kind of soup laced with growth media (substances that encourage cells to reproduce). When a sufficient number of cells developed, the disk would be surgically implanted in Sean’s chest. The cells would continue to grow inside his body, and as they did, the polymer disk Would gradually dissolve. After three months, if everything Went right, the disk would be completely gone, and in its place would be healthy, living cartilage.

Sean was glib“ about all of this: “I’m a guinea pig,” huh?” But when his parents told him the decision was his, he never hesitated.

Four surgeries later, Sean is equally glib about being the first human in history with a tissue—engineered chest. “Sorta cool,”13 he says, smiling. But his parents are gleeful. Debra says it makes her

indescribably happy to Watch her son saunter around with no shirt on 90 in front of his peers.” Sean has given up baseball in favor of BMX bike racing (“I don’t do anything crazy,” he claims. though he doesn’t hesitate to fly off ramps at outrageous speeds). In short, says his sister, Kelly “he’s my 17-year-old brother who rides around town and does 17-year-old things.” Which is precisely what his doctors had hoped to achieve.

Though Sean’s doctors preach caution, “We’ll want to continue to monitor him,” says Vacanti, “probably for the rest of his life.” they can scarcely hide their enthusiasm as they dream up other applications of the procedure. “The possibilities are phenomenal,” says Dr. Joseph Upton, who did Sean’s reconstructive surgery. “For example. I see a lot of patients who have facial paralysis.“ Boy, it sure would be nice if we could repair them with muscle from their own tissue. Right now its pie in the sky,15 but believe me, in five or ten years it wont be. And today I was working on a kid who was in a motorcycle accident and lost an awful lot of bone. Supposing We could repair that with a kind of injectable bone, instead of doing the huge amounts of bone grafts“ we have to do now? I think we will see such a product before too long.”