PITTSBURGH -- Doctors kept close watch Monday for rejection signs in a 35-year-old man who received a baboon liver in the first transplant of its kind.
The liver recipient, whose name was withheld, was in critical but stable condition Monday after Sunday's 11-hour transplant operation at the University of Pittsburgh's Presbyterian University Hospital, doctors said.
The surgery was performed in a last-ditch effort to save the patient, whose liver had been destroyed by the hepatitis B virus. Doctors said they did not want to use a human liver for the transplant because they feared it too would be ravaged by hepatitis B.
'Baboons cannot be infected with hepatitis B, so as sources for organs, they may offer a solution for these patients,' said Dr. Thomas Starzl, who headed the transplant team. 'The baboon offers a distinct advantage to the patient with hepatitis B -- a chance to live.'
The hepatitis B virus can be transmitted in blood products used for transfusion or by the use of contaminated needles, especially among intravenous drug users. The infection can lead to death by killing liver cells.
'Combating rejection, especially in a xenotransplant (animal-to-man) model, is the ultimate challenge,' Starzl said. 'We believe we now have an effective combination of drugs capable of suppressing the recipient's immune system so that the foreign, animal organ is not rejected.'
The Pittsburgh patient was being treated with FK506, which curbs the immune system's attack on foreign tissue, and three other anti-rejection drugs.
The University of Pittsburgh's review board Friday approved the operation and up to three more baboon liver transplants. Doctors immediately sought the patient's consent for the transplant. Included in the consent was a stipulation surgeons wait 24 hours before operating in case the patient changed his mind.
The decision to use an animal organ in a human was not without precedent.
The first attempt to use non-human organs in transplants took place in 1963, when doctors implanted chimpanzee kidneys into a human recipient. Those kidneys eventually were rejected.
In 1964, Dr. James Hardy of the University of Mississippi stitched the heart of a chimpanzee into a 68-year-old man who survived only two hours while Dr. Denton Cooley of Houston in 1968 tried to transplant a sheep heart into a 48-year-old man, who also died within two hours.
In perhaps the most publicized cross-species transplant, doctors at Loma Linda University Medical Center in California transplanted a baboon heart into an infant dubbed 'Baby Fae' in 1984. The baby lived about three weeks, making her the longest-surviving person with the heart of another species.
The first successful transplant of a human liver into a human patient was performed in 1967 at the University of Colorado in Denver. Currently, about 2,000 people worldwide undergo liver transplants each year and thousands more are on waiting lists for such procedures.
Starzl estimated about three patients die in Pittsburgh each week while awaiting a liver transplant and about 30 percent of all patients seeking a human liver die before getting one.
'There's an enormous shortage of organs these days,' said Starzl, who said his institution has a list of about 400 people waiting for livers.
