If your virtual doctor finds something wrong, such as a diseased organ, then he might order a new one to be grown
directly from your own cells. “Tissue engineering” is one of the hottest fields in medicine, making possible a “human
body shop.” So far, scientists can grow skin, blood, blood vessels, heart valves, cartilage, bone, noses, and ears in the
lab from your own cells. The first major organ, the bladder, was grown in 2007, the first windpipe in 2009. So far, the
only organs that have been grown are relatively simple, involving only a few types of tissues and few structures.
Within five years, the first liver and pancreas might be grown, with enormous implications for public health. Nobel
laureate Walter Gilbert told me that he foresees a time, just a few decades into the future, when practically every organ
of the body will be grown from your own cells.
Tissue engineering grows new organs by first extracting a few cells from your body. These cells are then injected
into a plastic mold that looks like a sponge shaped in the form of the organ in question. The plastic mold is made of
biodegradable polyglycolic acid. The cells are treated with certain growth factors to stimulate cell growth, causing
them to grow into the mold. Eventually, the mold disintegrates, leaving behind a perfect organ.
I had the opportunity to visit Anthony Atala’s laboratory at Wake Forest University in North Carolina and witness
this miraculous technology firsthand. As I walked through his laboratory, I saw bottles that contained living human
organs. I could see blood vessels and bladders; I saw heart valves that were constantly opening and closing because
liquids were being pumped through them. Seeing all these living human organs in bottles, I almost felt as if I were
walking through Dr. Frankenstein’s laboratory, but there were several crucial differences. Back in the nineteenth
century, doctors were ignorant of the body’s rejection mechanism, which makes it impossible to graft new organs. Plus,
doctors did not know how to stop the infections that would inevitably contaminate any organ after surgery. So Atala,
instead of creating a monster, is opening an entirely new lifesaving medical technology that may one day change the
face of medicine.
One future target for his laboratory is to grow a human liver, perhaps within five years. The liver is not that
complicated and consists of only a few types of tissue. Lab-grown livers could save thousands of lives, especially those
in desperate need of liver transplants. It could also save the lives of alcoholics suffering from cirrhosis. (Unfortunately,
it could also encourage people to keep bad habits, knowing that they can get replacement organs for their damaged
If organs of the body, like the windpipe and the bladder, can be grown now, what is to prevent scientists from
growing every organ of the body? One basic problem is how to grow the tiny capillaries that provide blood for the
cells. Every cell in the body has to be in contact with a blood supply. In addition, there is the problem of growing
complex structures. The kidney, which purifies the blood of toxins, is composed of millions of tiny filters, so a mold
for these filters is quite difficult to create.