The phase I multicenter trial, cleared by the U. S. Food and Drug Administration, uses transgenic pig livers as an ex vivo, or outside the body, support system to extend a patient's life until a human donor liver becomes available. Using a perfusion process similar to dialysis, transplant specialists divert the patient's blood outside the body through a catheter and pass it through the pig liver to remove toxins before returning the blood to the patient's body. The patient's liver is left in place during the procedure. When a human donor liver becomes available for transplantation, the ex vivo liver perfusion is terminated.
Data from the trial will be presented in a scientific peer-reviewed forum at the conclusion of the research study in 1998.
"As a leader in transplantation, Northwestern continues to apply science and technology to save patient lives. However, while we're hopeful this research will bring about new discoveries in the field of transplantation, there is still a critical need for donor organs," said Jonathan Fryer, M.D., principal investigator for the study at Northwestern. Fryer is an assistant professor of surgery at Northwestern University Medical School and a transplant surgeon at Northwestern Memorial Hospital.
"The findings from the research will ultimately affect organ availability for all patients waiting for transplantation and give us critical insight into how to prevent rejection of all transplanted organs," he said.
Each year, an estimated 3,000 Americans die waiting for a donor organ.
An additional 100,000 die without even having qualified for the waiting list. Promising research has demonstrated the possibility of using transgenic pig organs to alleviate the dramatic shortage of human donor organs. Baxter's Nextran unit has developed genetically engineered pigs designed to overcome one of the major obstacles to successful organ transplantation -- rejection of the donor organ by the recipient's immune system -- which helps to prolong the life of the patient until a human organ becomes available.
Researchers at Nextran have genetically engineered pigs to express on the surface of their organs human proteins that regulate the immune response. By introducing the genes for certain human regulatory proteins into a fertilized pig egg, which is then allowed to develop normally, the researchers have produced pigs that possess the human proteins necessary to interrupt the immune response before complement proteins can mark the organ as "foreign" and destroy it.
"While this development program is still in its early stages, we already have gained valuable insight into the human immune response, and the rejection process in particular," said John Logan, vice president of research and development at Nextran.
"The knowledge we gain at Northwestern and other study sites is paramount to reaching our goal of transplanting these organs directly into patients, supplementing the need for human donors and eventually saving thousands of lives each year," he said.
This clinical research trial represents a continuation of a strong transplant program at Northwestern, including the first kidney transplant in Illinois and, more recently, the first pancreatic islet cell transplant. The hospital's first small bowel transplant was conducted in 1996, and bone marrow transplant clinical trials are currently under way to alleviate such autoimmune diseases as lupus, multiple sclerosis and rheumatoid arthritis.
Northwestern Memorial Hospital is the primary teaching hospital for Northwestern University Medical School. It is a member of the Northwestern Healthcare Network and is widely regarded as one of the nation's pre-eminent medical centers.
Nextran, Inc., based in Princeton, N.J., is a unit of Baxter Healthcare Corporation that develops organ transplant technologies to improve the success and increase the availability of organ transplantation. Baxter Healthcare Corporation is the principal U.S. operating subsidiary of Baxter International Inc.
(Source Contact: Deborah Spak, Baxter Healthcare Corporation at 847-948-2349 Elizabeth Crown, Northwestern University at 312-503-8928 or e-mail at e-crown@nwu.edu ; Lauri Sanders, Northwestern Memorial Hospital at 312-908-7432 or e-mail at lsanders@nmh.org)