Lost a lung? Grow your own

By Ben Bova

Mamas, don't let your babies grow up to be cowboys, says the old song. It would be smart not to let them grow up to be surgeons, either.

Surgery is on the way out.

Surgery won't disappear completely this year, or next, but the first steps in replacing surgery already have taken place in several research laboratories.

Instead of surgery, the future holds promise of regeneration - getting the body's own cells to replace defective tissue or grow new, healthy organs or limbs.

This week researchers in Germany reported they have triggered the growth of new blood vessels in 20 volunteer heart bypass patients by giving them a genetically engineered growth hormone.

And at a 1997 meeting of the American Heart Association, scientists from St. Elizabeth's Medical Center in Boston reported that they have injected 20 patients with a laboratory-produced version of the human gene that makes a protein, which spurs the growth of blood vessels in human fetuses. Sixteen of the 20 patients, who suffered from severely clogged arteries in their legs, grew new arteries that carry blood around the clogged vessels. The constant pain that had afflicted them has been relieved, and they have been spared the need for leg amputations.

By learning how to get the body to generate new blood vessels on demand, the need for bypass surgery eventually will be eliminated altogether. Why cut blood vessels from various parts of the body and sew them into the heart's arterial system when you can get the body to grow new coronary arteries on demand?

Earlier last year, a pair of Harvard researchers announced that they had grown entire replacement organs - including hearts, kidneys and bladders - for lab rats, rabbits and sheep. They used the animals' own cells as the starting material, grew the new organs in the laboratory, and then implanted them surgically into the animals.

The scientists who made this announcement pointed out that one of the earliest uses of their work could be to correct birth defects while the fetus is still in its mother's womb.

They gave the example of a fetus with a malformed trachea. Surgeons could take some of the fetus' cells, grow a new windpipe for the fetus, and have it ready as soon as the fetus is born. Since the replacement organ is made from the fetus's own cells, there would be no problem with tissue rejection as there is with today's organ transplant procedures.

When an organ is transplanted from another person, the recipient's immune system recognizes the transplanted organ as foreign tissue and attacks the organ just as it would attack invading microbes. Successful transplants depend on drugs that suppress the recipients' immune systems, a requirement that has considerable drawbacks.

A friend of mine lost function in both his kidneys due to a disease inherited through his mother. His father donated one of his kidneys to save his son. The transplant worked, but the man has spent the past 10 years on immune-suppressive medications. He's alive, but his lifestyle is greatly slowed down, and he is in constant danger from the slightest infection or cold virus.

If the transplant tissue were made of the recipient's own cells, the problem of rejection by the immune system no longer would exist.

In August, the Food and Drug Administration issued a license to Genzyme Corp.'s Tissue Repair division for Carticel, a proprietary process that allows a patient's own cartilage cells to repair knee damage. Several hundred patients have used Carticel in implant procedures in 1997.

Within five years, we should see the field of organ transplants begin to change into the field of organ regeneration. Eventually, there will be no need to hunt for organ donors, no need to wait for some unfortunate accident victim's death so you can get yourself a healthy heart.

And it won't stop there. If new organs can be grown in the laboratory, why can't you grow new organs or limbs in your own body? Why have coronary bypass surgery if you can grow new coronary arteries right there in your chest? Why get a prosthetic knee if you can build a new one out of your own cells? Why undergo cosmetic surgery if you can grow smooth, young skin and tighter muscles for yourself?

Surgery is one of the oldest professions. Prehistoric skulls show evidence of surgical work from 10,000 years ago.

But its day is coming to an end. New understanding of how to get body cells to regenerate and repair damage will inevitably replace the scalpel.

Mamas, do let your babies grow up to be molecular biologists.

Ben Bova, a member of USA TODAY's board of contributors, can be reached at www.sff.net/people/benbova. He is author of the new novel, Moonwar.

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