CHICAGO --- Researchers at Northwestern University Medical School andNorthwestern Memorial Hospital announced today that because of the chronicshortage of human donor organs for transplantation, they have joined with BaxterHealthcare Corporation in a nationwide clinical trial using genetically altered(transgenic) pig livers as a temporary "bridge" to help patients dying ofend-stage liver failure. With the aid of the transgenic livers, developed byBaxter's Nextran unit, it is hoped that more patients will be able to surviveuntil a human donor liver becomes available for transplantation.
The phase I multicenter trial, cleared by the U. S. Food and DrugAdministration, 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 becomesavailable. Using a perfusion process similar to dialysis, transplant specialistsdivert the patient's blood outside the body through a catheter and pass itthrough the pig liver to remove toxins before returning the blood to thepatient's body. The patient's liver is left in place during the procedure. Whena human donor liver becomes available for transplantation, the ex vivo liverperfusion is terminated.
Data from the trial will be presented in a scientific peer-reviewedforum at the conclusion of the research study in 1998.
"As a leader in transplantation, Northwestern continues to apply scienceand technology to save patient lives. However, while we're hopeful this researchwill bring about new discoveries in the field of transplantation, there is stilla critical need for donor organs," said Jonathan Fryer, M.D., principalinvestigator for the study at Northwestern. Fryer is an assistant professor ofsurgery at Northwestern University Medical School and a transplant surgeon atNorthwestern Memorial Hospital.
"The findings from the research will ultimately affect organavailability for all patients waiting for transplantation and give us criticalinsight 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 pigorgans to alleviate the dramatic shortage of human donor organs. Baxter'sNextran unit has developed genetically engineered pigs designed to overcome oneof the major obstacles to successful organ transplantation -- rejection of thedonor organ by the recipient's immune system -- which helps to prolong the lifeof the patient until a human organ becomes available.
Researchers at Nextran have genetically engineered pigs to express onthe surface of their organs human proteins that regulate the immune response. Byintroducing the genes for certain human regulatory proteins into a fertilizedpig egg, which is then allowed to develop normally, the researchers haveproduced pigs that possess the human proteins necessary to interrupt the immuneresponse before complement proteins can mark the organ as "foreign" and destroyit.
"While this development program is still in its early stages, we alreadyhave gained valuable insight into the human immune response, and the rejectionprocess in particular," said John Logan, vice president of research anddevelopment at Nextran.
"The knowledge we gain at Northwestern and other study sites isparamount to reaching our goal of transplanting these organs directly intopatients, supplementing the need for human donors and eventually savingthousands of lives each year," he said.
This clinical research trial represents a continuation of a strongtransplant program at Northwestern, including the first kidney transplant inIllinois and, more recently, the first pancreatic islet cell transplant. Thehospital's first small bowel transplant was conducted in 1996, and bone marrowtransplant clinical trials are currently under way to alleviate such autoimmunediseases as lupus, multiple sclerosis and rheumatoid arthritis.
Northwestern Memorial Hospital is the primary teaching hospital forNorthwestern University Medical School. It is a member of the NorthwesternHealthcare Network and is widely regarded as one of the nation's pre-eminentmedical centers.
Nextran, Inc., based in Princeton, N.J., is a unit of Baxter HealthcareCorporation that develops organ transplant technologies to improve the successand increase the availability of organ transplantation. Baxter HealthcareCorporation is the principal U.S. operating subsidiary of Baxter InternationalInc.
Materials provided by Northwestern University. Note: Content may be edited for style and length.
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