Genetic Work on Liver Cells Shows Promise for Therapy
Genetic manipulation of liver cells is pointing toward a promising new therapy that one day might provide support for patients awaiting a liver transplant, offering hope for the 20 million Americans who suffer from liver disease.
Laboratory experiments that restored normal function in rats who had 90% of their livers surgically removed suggest that the genetic manipulation of cells grown in test tubes could rejuvenate failing liver functions.
Researchers at Brigham and Women’s Hospital in Boston found a way to grow millions of liver cells, called hepatocytes, and then transplant them into rats that had virtually no liver function. The new liver cells took over the job of the failing organ, the scientists report in today’s Science.
“I have no idea when we could use it in humans” because the technique is still so experimental, said Dr. Philippe Leboulch, the chief researcher on the study. But he said it offers the promise of one day helping stave off organ failure in patients waiting for a liver transplant.
Leboulch said transplanted liver cells have been used in patients with failing organs before, but the therapy had limited success because doctors were unable to isolate enough liver cells. Hepatocytes are very difficult to grow in the laboratory.
The new technique uses an inserted cancer gene that allowed the cells to start reproducing without limit, a technique known as “immortalizing.” Although the cells multiplied by the millions, they could not be transplanted because in the body they would be like a cancer, growing out of control.
To solve this problem, the researchers treated the cells with an enzyme that acts like “genetic scissors.” It cut out and deactivated the inserted cancer gene, halting the rapid growth of new cells.
About 60% of the treated animals lived normally after receiving the cells, while all rats not receiving them died within three days.
About 400,000 of the 20 million Americans with liver disease die annually. Liver transplants are the only hope for many of these patients, but there are only enough organs to treat about 4,000 patients each year.
