Toward a Substitute Liver

If a man's liver stops working, he soon lapses into a deep coma and usually dies within a few weeks. Drugs offer little help, and transplants are all but hopeless. Even if the rejection mechanism could be overcome, there would still be the crucial problem of supply, which can only be met by cadavers; unlike kidney donors, who have a second kidney to keep them going, no man can donate his liver and live. But the liver has a remarkable ability to regenerate damaged cells and rebuild lost tissue--an ability which suggested to University of Kentucky Surgeon Ben Eiseman that if a diseased human liver could be given a vacation from its vital work, it might rebuild itself sufficiently to start functioning properly once more.,

Sound Reasons. But there is no arti ficial liver comparable to the artificial kidney, and there is no hope of devising one soon, because the liver's multiple tasks are even more complex than the kidneys'. Surgeon Eiseman eventually decided to use a pig's liver, and for sound medical reasons: a pig's liver is about the same size as a man's, performs the same functions, is just about the cleanest liver in the animal kingdom.

In complex lab tests, Surgeon Eiseman ran human blood through excised pig livers, and found to his relief that they tolerated all blood types. This encouraged him to try hooking up pig livers to human patients. He and his colleagues chose eight patients in the last stages of liver coma and set up their operations as they would have for transplants. Each time, they removed the pig's liver and placed it in a steel perfusion chamber alongside the patient.

The pig liver was washed free of its own blood, cooled down to 54DEG F., and injected with antibiotics to kill any bacteria that might be present. Tubes were inserted in one of the patient's main arteries and one of his large veins; his own heart served as the pump to send his blood into the pig's liver. From there, the blood went back into the patient's vein after being rewarmed along the way to a normal 98.6DEG F.

To avoid the danger of clotting, the surgeons injected the anticoagulant heparin into the plastic tube leading blood away from the patient. But before it got back into the patient, where the clotting factor was necessary once more, the doctors gave it another injection, this time of protamine, to counteract the heparin.

Help in Crises. None of the eight patients lived, and none were expected to. Seven were victims of severe al coholic cirrhosis, and the pig-liver substitute worked well for only about six hours at a time, which was nowhere near long enough to let the patients' livers recover. But only two men failed to respond to the treatment, and five came out of their coma long enough to obey spoken commands. One asked for a cigarette on the operating table, and another was coherent for four days.

One of the Kentucky surgeons' patients had two perfusions; one who had three responded well to the first and second. Dr. Eiseman now believes that if pig-liver perfusions can be prolonged to 24 hours, they may be of real help in crises for hepatitis patients and cirrhosis victims who still have a little liver function remaining, and also for transplant recipients immediately after surgery if liver transplants ever become practicable.

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