Recipient of Baboon Liver Stable After Historic Surgery : Medicine: Surgeon says patient’s response is comparable to having received a human organ. But such cross-species transplants may pose unknown problems.
A terminally ill 35-year-old man who received a baboon liver in a historic but untested operation was said by doctors Monday at University of Pittsburgh Medical Center to be doing as well as could be expected.
The 11-hour surgery, which ended late Sunday, is the first known baboon-to-human liver transplant. If the experiment succeeds, it is likely to focus renewed interest on the use of animals for transplants because of the shortage of human organs.
The patient, about whom no personal details were released, “is in stable but critical condition,” Dr. Andreas Tzakis, one of the surgeons, said at a news conference. “He is awake. He is able to respond to simple commands,” such as a request to squeeze his fingers.
Tzakis added that the patient is on a respirator and unable to speak.
“So far, the course has been quite comparable to what we would expect to see (with a human liver), if we had operated on a patient who was as ill,” he said.
The man was infected with hepatitis B, a virus that destroyed his liver. He had low priority to receive a human liver because the new liver is often fatally damaged by the virus.
In contrast, the baboon’s liver appears to be less susceptible to hepatitis B infection, the Pittsburgh surgeons said. Without the surgery, the patient was expected to die of liver failure within weeks.
There have been nearly 30 cross-species organ transplants throughout the world since 1963 and all have failed. The last was the 1984 transplant of a baboon heart into an infant girl by Dr. Leonard L. Bailey at Loma Linda University Medical Center. The girl, Baby Fae, died 21 days after the surgery.
Bailey said Monday that he “was really excited by the news from Pittsburgh” as well as new data from his laboratory where a baboon, named Max, was given a heart from a rhesus monkey and has survived for more than a year. “We are very optimistic,” he said.
In an interview, Bailey, who has pioneered infant heart transplants, said he would apply to the university within the next few months for permission to temporarily transplant baboon hearts into desperately ill infants. His goal is to give the infants enough time until a human heart becomes available. In the last year, Bailey said three babies who died before a human heart could be found might have been helped by this procedure.
In Pittsburgh, surgeons expressed optimism that their experiment would succeed. If the transplant succeeds, their patient could leave the hospital in about a month.
The surgeons used a combination of four powerful drugs to suppress the immune system and prevent the rejection of the baboon liver. The drugs are FK-506, a highly touted experimental anti-rejection drug; cyclophosphamide, which is used in cancer treatment; prednisone, a steroid, and the anti-inflammatory medication prostaglandin.
This man “is a very brave person,” said Dr. Thomas E. Starzl, who directed the transplant team. “He had an extremely positive attitude.”
The surgeons and the university’s Institutional Review Board, which oversees human experiments, said they presented a realistic picture of the surgery to the patient and his family. The consent form that the patient signed was as “dismal as could be constructed,” said Jeffrey A. Romoff, president of the medical center. The outcome is unknown and there is “the possibility of imminent death,” he said.
Liver transplant surgeons at other universities said the operation was very interesting but warned that many problems may lie ahead.
“The important questions are not only whether the patient is going to survive but what the experiment means in the long term,” said Dr. Jameson Forster, director of the liver transplant program at the Kansas University Medical Center in Kansas City. “Even if rejection of the liver can be prevented, it is not known whether the proteins the baboon’s liver produces are going to work in humans.”
Dr. Ronald Busuttil, director of the UCLA liver transplant program, said “a lot more work needs to be done” to understand cross-species transplants. He said that although the baboon liver might be protected against hepatitis B, it might be susceptible to diseases to which humans are immune.
The University of Pittsburgh surgeons have permission to perform three additional baboon-to-human transplants. The baboon killed to allow its liver to be transplanted was a 15-year-old male from the Southwest Foundation for Biomedical Research in San Antonio, Tex.
There were 2,946 liver transplants in the United States in 1991; more than 1,800 people are waiting for the surgery. About a quarter of those waiting may die before they can receive a transplant, experts said.
