As a transplant and reconstructive surgeon, Dr. Joseph Vacanti of Boston's Children's Hospital knows better than anyone how great the need is for replacement tissue and organs for transplant. "All you have to do is walk down the halls of this hospital and you see it on every floor," he says. "On the transplant unit it's children needing kidneys, livers, and other organs. On the general surgical unit it's children born with no esophagus or without enough intestine. In the urology division, it's children born without bladders or incomplete tubes to drain their urine. And on the orthopedic floor there are children devastated because they don't have cartilage in part of their face or enough bone to develop proper limbs." Beyond the walls of Children's Hospital, several million more people are also desperate for new body parts. Some have been injured in accidents or lost their organs to disease; some are elderly persons who suffer degenerative conditions such as arthritis; and still others are athletes whose bodies have worn out prematurely from tremendous strain. In the United States alone, over a million procedures are done each year to repair injuries to cartilage, including over 558,000 joint replacements and 30,000 facial reconstructions. About 275,000 bone grafts and 480,000 breaks or fractures that could use "bone patching" also occur each year. In addition, over 200,000 people a year are awaiting liver transplants (30-50,000 die from liver disease); 728,000 need a new pancreas; 100,000 need new intestinal lining; and 100,000 (particularly newborns with congenital malformations, and some elderly persons) need a new lining for the urethra.
Some of these people receive transplants (which then leads to a lifetime of immunosuppressive medication), assist devices, or surgical patchwork, but for many there is nothing that can be done to help them. The supply of organs and other tissues for transplant is also notoriously inadequate (only about 2,500 people receive liver transplants each year), and the threat of AIDS and other transmissible diseases, such as hepatitis B, has made transplants between persons an even more dangerous operation.
In addition, some body parts cannot be provided by transplants, and their artificial counterparts, or even "makeshift" versions using other tissues with similar functions or characteristics (such as a piece of colon exchanged for a missing section of esophagus, or intestine used as a patch for missing bladder tissue), never perform as well as the real thing and can provoke serious reactions.
Bioengineering: a new approach
So why not just biologically engineer new organs from cells provided by the patients themselves? The thought is intriguing, but
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