New Hope for Organ Transplants

New hope for increasing the nation's too-small supply of transplantable organs came Thursday as researchers publicized the completion of a significant step forward in developing pig organs for use in human patients. The announcements came from scientists on two different teams, one from PPL Therapeutics Inc. in Blacksburg, Virginia, and the other representing a joint effort by the University of Missouri and Immerge BioTherapeutics Inc., based in Charlestown, Massachusetts. Both groups reported they have produced pigs that lack GGTA1, one of two genes that cause the human body to reject organs harvested from swine. Experts, while careful to note that the final goal of transplantable pig organs is still years away, hailed the news. "It is not the final hurdle, but it is very important," said Dr. Jeffrey L. Platt, of the Mayo Clinic.

Scientists used cloning methods to locate and remove the GGTA1 gene from the pigs. GGTA1 is one of two genes that trigger the human immune response and resulting organ rejection. If a strain of pig is developed that lacks these genes, scientists believe that they could harvest their vital organs, such as the heart and lungs, and use them successfully in human patients. Such a process could shorten the wait for organ transplants, saving human lives. There are currently almost 80,000 people in need of organs for transplant in the U.S., according to the United Network for Organ Sharing.

Still, using pig organs as a viable option in transplant cases won't happen anytime soon. Scientists believe it will be roughly four years before pig organs will be available for transplant purposes. The odds were against success in the removal of the first gene copy from the pigs, and are even slimmer in the case of the second. "It was one in 5 million when we had two targets," said Julia L. Greenstein, of Immerge BioTherapeutics Inc. "Now we've got to be twice as good to get the other one."