Mar. 12, 1998
Researchers at the University of Minnesota have developed an artificial liver using living cells that will temporarily support patients with severe liver failure as they wait for a liver transplant or recover from liver injury. Algenix Inc., a Minnesota-based company, is working with the university to commercialize the device. Algenix has licensed the technology from the university and is seeking investors to begin clinical trials.
Approximately 250,000 individuals are admitted to hospitals in the United States each year for diseases associated with liver failure. The American Liver Foundation reports that liver failure is the seventh leading cause of death in the country, having caused 40,000 deaths in 1996. Approximately 4,100 liver transplants are performed nationwide each year, but more than twice that many patients are on the waiting list. Patients with liver disease and their insurance companies spend more than $9 billion in hospital charges annually in the United States.
The university's bioartificial liver provides the essential functions that are disrupted by liver disease: detoxifying the blood and regulating the amount of glucose, protein, fat and other substances that enter the bloodstream.
The device uses pig liver cells to destroy the toxins that accumulate in the blood following liver failure. Patients will be connected to the device, which is similar in design and application to what is used for kidney dialysis. The dialysis cartidge is filled with hollow fibers whose walls function as a membrane. The pig cells are suspended in a collagen gel inside the fibers. Blood is purified by being circulated out of the patient's body and around the outside of the fibers. The fiber membrane allows the toxins, which are small molecules, to diffuse through it and into the gel, where they are destroyed by the pig cells. The patient's blood cells are too big to get into the fibers, and so never touch the pig cells. The purified blood is returned to the patient.
Nationwide, researchers are exploring several other approaches to artificial livers, most of which use pig liver cells. The university's device is unique because the patient's blood never comes into contact with the pig cells, thereby minimizing the possibility that an animal virus could be transferred to humans. It also provides a better nutritional environment for the pig cells and sustains their vitality because they are shielded from the patient's immune defenses.
The technology has gone through extensive experimental testing at the university since 1988, and has been found safe and effective in preclinical trials. The project was headed by Dr. Frank Cerra, professor of surgery and senior vice president for health sciences, and Dr. Wei-Shou Hu, professor of chemical engineering and materials science. The Food and Drug Administration has approved the use of this device for a clinical trial in humans.
Although the risk of transferring a harmful virus from the pig cells is minimal with this device, the researchers said they are taking every precaution to protect the patient. "The bioartificial liver team and Algenix Inc. are collaborating with a team of researchers with expertise in animal husbandry, porcine virology and biomedical swine research to develop protocols to safeguard the patient and the public," Hu said. "The university is one of the very few institutions in the country with researchers whose expertise encompasses such a wide range of issues related to swine for biomedical research. This collaboration ensures the highest quality and consistency of the bioartificial liver device."
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