May 2006

A Lifesaving Liver Machine

A dialysis device uses pig liver cells.

By Tom Mashberg

With human liver tissue in critically short supply, the Mayo Clinic in Rochester, MN, is working to create a liver dialysis machine that uses pig liver cells. It's a step up from using whole pig livers for temporary treatment, because isolated cells present a lower risk of contamination and can stay alive longer.

Principal investigator Scott L. Nyberg tested his machine in late 2005 in a preclinical study on dogs with drug-induced liver failure. The dogs on the machine lived longer than control subjects and did not develop signs of brain swelling. "We want to extend the life span of the cells and duration of the treatment" compared to existing methods, Nyberg says. Some 40,000 Americans die of liver failure annually; Nyberg recalled a teenager who died 14 hours before a donor became available. "A device like this could have kept her alive just that one more day."

The device looks like a fish tank on a tilting platform. The tank holds an oxygenated liquid medium and about 500 grams of live liver cells, or hepatocytes, from pigs. The cells survive for up to a month when not in use and lasted 48 hours during the dog tests.

The blood of a liver patient would be filtered to remove white blood cells and immune proteins, so they can't attack the pig cells. The remainder would then mix with the hepatocytes for waste removal, pass through a membrane that blocks the pig cells, and reunite with the rest of the blood. Nyberg is preparing to do more animal tests; human trials could begin in 2008.

With human liver tissue in criti-cally short supply, the Mayo Clinic in Rochester, MN, is working to create a liver dialysis machine that uses pig liver cells. It's a step up from using whole pig livers for temporary treatment, because isolated cells present a lower risk of contamination and can stay alive longer.

Principal investigator Scott L. Nyberg tested his machine in late 2005 in a preclinical study on dogs with drug-induced liver failure. The dogs on the machine lived longer than control subjects and did not develop signs of brain swelling. "We want to extend the life span of the cells and duration of the treatment" compared to existing methods, Nyberg says. Some 40,000 Americans die of liver failure annually; Nyberg recalled a teenager who died 14 hours before a donor became available. "A device like this could have kept her alive just that one more day."

The device looks like a fish tank on a tilting platform. The tank holds an oxygenated liquid medium and about 500 grams of live liver cells, or hepatocytes, from pigs. The cells survive for up to a month when not in use and lasted 48 hours during the dog tests.

The blood of a liver patient would be filtered to remove white blood cells and immune proteins, so they can't attack the pig cells. The remainder would then mix with the hepatocytes for waste removal, pass through a membrane that blocks the pig cells, and reunite with the rest of the blood. Nyberg is preparing to do more animal tests; human trials could begin in 2008.