Organ Transplants from Animals : Part 3

by Food and Drug Administration (FDA)

(Page 3 of 3)

Transplant physicians try to suppress the immune system with powerful drugs. While these drugs are often successful, they leave the patient vulnerable to many infections. FDA-approved immunosuppressive drugs include Sandimmune (cyclosporine), Imuran (azathioprine), Atgam (lymphocyte immune globulin), Prograf (tarolimus), and Orthoclone (muromonab-CD3). New drugs are also being researched, including some "designer" immune suppressants. These drugs may enable doctors to suppress the immune system from rejecting a particular organ, but leave the rest of the body's immune system intact.

Drugs designed to help transplant patients may end up also aiding those who are stricken with diseases such as arthritis, multiple sclerosis and diabetes, because these involve problems with the human immune system. For example, Imuran is approved to treat severe rheumatoid arthritis, and Prograf has already shown some promise to MS patients. A large study is under way to determine if it is effective.

Genetic engineering is the next step in battling organ rejection. Researchers have begun experimenting with ways to insert human genes into animal organs, so that the organs will produce proteins the body will recognize as "human." FDA is active in basic research that may lead to better gene therapies and ways of manipulating animal organs.

For example, Judy Kassis, Ph.D., an FDA biochemist, has been studying a fruit fly gene that is important to the insects' early development. Using some DNA and a harmless virus, she has developed a way to insert this gene precisely into its natural position on the fly's chromosomes. Carolyn Wilson, Ph.D., an FDA virologist, has been researching pig viruses and whether they could infect humans in a transplant setting.

FDA scientists are also studying ways that individual genes "turn on" as they develop, how viruses activate each other, and how viruses can be used safely to deliver genes for new therapies.

"Gene therapy is really in its infancy," says Kassis. "That's the thing about basic research — you can't really predict how useful this will be in the future. Hopefully, it will have direct relevance someday."

Gene therapies and their role in xenotransplantations are still in the early stages of development. For now, it's only in science fiction that doctors can order a custom-designed pig liver from the hospital pharmacy. Whether or not that ever becomes reality, FDA's goal in regulating xenotransplant experiments is to make sure these procedures are openly discussed, that data is carefully collected, that patients give their fully informed consent, and that safety precautions are taken with every effort.

Transplant Organs: Too Little, Too Late

For patients with severe kidney failure, liver disease, heart defects, and other diseases, an organ transplant is often their only hope for survival. Surgeons have made great strides in transplant techniques, yet many patients never get the benefit of them. There are simply not enough organs to go around.

Human organs must be taken quickly from healthy people who have died through trauma such as car and motorcycle wrecks. The potential donor pool is small, and only about 20 percent of the families of trauma victims consent to have their loved ones become donors. Stricter seat belt and helmet laws have reduced motor vehicle deaths and the numbers of potential donors.

Even with increased public awareness of the need for organ donors, transplant surgeons predict the shortage will only get worse.

As of January, there were 44,000 Americans waiting for organ transplants, yet only 18,270 transplants were performed last year, according to the United Network for Organ Sharing, the organization that oversees organ donations. More than 28,000 people die of liver failure each year, yet only about 3,800 donors are available. Thousands of people die every year waiting for other organs. Many more never make the organ recipient list because they are too ill to receive one.

Organ donation is free to the donor. After organs are removed, the body is suitable for viewing and burial. Becoming a donor is simple — there are organ donor cards on the back of driver's licenses in many states. Even if you sign a card, make sure your family knows you want to be an organ donor. Hospital staffs always ask permission before arranging for donations.

About the Author

www.fda.gov
FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.