Engineering organs

By Christina Jeng

Staff Writer

At a time when nearly 90,000 Americans are on the organ transplant waiting list -- 3,000 of them from North Carolina -- the movie "The Island," which opened July 22, depicts a tempting proposition: Why wait when you can grow your own?

In the film, Ewan McGregor and Scarlett Johansson play clones who exist to produce spare organs for their sickly human counterparts.

But scientists say no reputable researcher would attempt human cloning, also called reproductive cloning.

Instead, to alleviate the growing need for organs, here are some alternatives researchers are working on:

Some myths

MYTH: Only hearts, livers and kidneys can be transplanted.

FACT: Needed organs include the heart, kidneys, pancreas, lungs, liver and intestines. Tissue types that can be donated include the eyes, skin, bone, heart valves and tendons.

MYTH: You are too old to be a donor.

FACT: People of all ages and medical histories should consider themselves potential donors. Your medical condition at the time of death will determine what organs and tissue can be donated.

MYTH: If emergency room doctors know you are an organ donor, they won't work as hard to save you.

FACT: If you are sick or injured and admitted to the hospital, the No. 1 priority is to save your life. Organ donation can only be considered after brain death has been declared by a physician. Many states have adopted legislation allowing individuals to legally designate their wish to be a donor should brain death occur, but in many states organ procurement organizations also require consent from the donor's family

MYTH: Organ donation disfigures the body and changes the way it looks in a casket.

FACT: Donated organs are removed surgically, in a routine operation similar to gallbladder or appendix removal. Donation does not change the appearance of the body for the funeral service.

MYTH: Your religion prohibits organ donation.

FACT: All major organized religions approve of organ and tissue donation and consider it an act of charity.

MYTH: There is real danger of being heavily drugged, then waking to find you have had one kidney (or both) removed for a black market transplant.

FACT: This tale has been widely circulated over the Internet. There is absolutely no evidence of such activity ever occurring in the United States. While the tale may sound credible, it has no basis in the reality of organ transplantation. Many people who hear the myth probably dismiss it, but it is possible that some believe it and decide against organ donation out of needless fear.

Source: United Network for Organ Sharing

Stem cells and walking rats

Rather than transplanting whole organs, researchers sometimes transplant cells.

One of those scientists is Dr. Hans Keirstead of the Reeve-Irvine Research Center at the University of California, Irvine. Keirstead and his team developed a method to differentiate human embryonic stem cells into a type of nerve cell called oligodendrocytes. Oligodendrocytes are the building blocks of myelin, the insulating layer that forms around nerve fibers and is critical for maintaining electrical conduction in the central nervous system. When myelin is stripped away by disease or injury, it can result in sensory and motor deficiencies and, in some cases, paralysis.

He transplanted the oligodendrocyte cells into spinal cord- injured adult rats seven days after their initial injury; myelin tissue formed and the rats were then able to walk. The treatment did not work on rats that had been injured for 10 months; in those animals, myelin could not form because the space surrounding neuron cells had filled with scar tissue.

"These are exciting days for the spinal cord injured community," Keirstead said.

However, Keirstead and his lab are in pre-clinical trials and he said they do not want to treat humans until they have conducted the necessary tests to run a responsible clinical trial.

"The spinal cord injury community is waiting with bated breath," Keirstead said. "We really are going as fast as we can."

Heart blanket

Named for the way it wraps around the heart, this device helps those suffering from heart disease by giving the heart an extra boost.

Researchers at Britain's University of Leeds are engineering the cardiac assist device, which consists of several bands around the heart. These bands will contract to squeeze blood out in the same way healthy heart muscle does with every beat.

Dr. Peter G. Walker, lead researcher on the project, likens it to an emergency surgeon who puts his hand around a failing heart and pumps it.

"If you have a heart that's suboptimal -- you can sit around but not walk -- the device will help," Walker said.

He said the heart blanket would be an improvement over the mechanical pumps used today, which can cause blood clots.

The device uses tiny motors, which are connected to the bands around the heart. Then pacemaker technology is used to sense the natural heart beat signal so that the bands can contract along with the heart.

The heart blanket can be used temporarily for those awaiting transplants, and it can help a person who has just had a heart transplant recover by assisting the new heart. At this time, 3,142 people are waiting for a heart.

What you can do

In 2004, there were 7,150 deceased organ donors and 6,990 living organ donors. Today there are about 90,000 Americans on the transplant organ waiting list and about 5,000 donors. Every 12 minutes a name is added to the national transplant waiting list and an average of 17 people on the transplantation waiting list die each day.

You can become a donor by signing a donor card, indicating your wishes on your driver's license, or listing yourself with a donor registry. However, it may fall to your family to give final consent, so share your wishes with them.

"Every person has the power to enhance or save up to 50 lives by becoming an organ or tissue donor," said Anne Paschke of the United Network for Organ Sharing.

For more information, go to: www.unos.org/help

Baking a bladder

Growing an artificial bladder is like baking a cake, according to Dr. Anthony Atala at Wake Forest University's Institute for Regenerative Medicine.

His recipe for bladder:

Perform a small biopsy from the patient's bladder (remove a batch of tissue cells about half the size of a postage stamp).
Grow cells in large quantities by applying growth factors.
Place cells onto a three-dimensional mold or scaffold shaped like a bladder.
Implant the model into the patient, where the scaffold will eventually degrade.
Allow the new organ or tissue to integrate with body.

Atala said his research with engineering organs is still at the preclinical stage, which means it has not been tested in humans. However, when he transplanted these artificial bladders into dogs that lacked functional bladders, the organs developed and functioned normally after a month.

Atala has helped develop urethras (the tube urine passes through from the bladder), which have successfully been implanted in humans.

He has created blood vessels, muscle, wombs and vaginas, which have been successfully tested in animals and are close to being ready to test in humans.

Staff writer Christina Jeng can be reached at 812-0822 or cjeng@newsobserver.com.

This article posted August 23, 2005.