Although the two therapies take fundamentally different approaches to treating potentially fatal liver diseases, each attempts to prolong the useful lives of liver cells in order to correct liver damage or delay liver failure, say lead researchers in separate interviews with WebMD.
In the first study, researchers at Harvard Medical School in Boston and the Albert Einstein College of Medicine in New York report that cirrhosis of the liver -- and perhaps some other progressive, fatal diseases -- could be slowed, stopped, or even prevented with genetic therapy. Cirrhosis is the potentially fatal scarring of the liver, which can lead to liver failure. According to the National Institutes of Health, cirrhosis of the liver is the seventh leading cause of death by disease in the world.
Many diseases such as cirrhosis are characterized by a high, ongoing rate of cell death and an organ's inadequate ability to reproduce its cells, according to Ron DePinho, MD, American Cancer Society research professor at the Dana Farber Cancer Institute at Harvard Medical School. Decades of this kind of cell turnover can result in liver failure, he says.
He and his colleagues found evidence that showed cirrhosis of the liver might be related to damage to the genetic material DNA. The liver has a remarkable capacity to grow new cells, and the researchers surmised that this DNA damage may lead to destruction rather than regrowth of liver cells.
The researchers tested a form of gene therapy in mice that were bred to have the abnormal DNA that scientists felt was related to the development of cirrhosis. A normal copy of the gene was injected into the mice and the treated mice had restored normal DNA function and near-normal liver cell growth as well as an improvement in liver function.
In the second study, researchers in Japan and the U.S. were able to genetically alter normal human liver cells so that they would continue to reproduce indefinitely. The researchers then transplanted the human cells into rats with liver failure. The rats were treated with immune-system suppressing drugs to prevent the rats from rejecting the human cells. Almost all of the rats had significant improvement in their liver function. The transplanted cells apparently provided sufficient life-saving support for the rats' severely damaged livers to regenerate.
Principal investigator Philippe Leboulch, MD, PhD, assistant professor of medicine at Harvard Medical School and a physician at Brigham and Women's Hospital in Boston, tells WebMD that this therapy, if proven to be safe in humans, could buy crucial time for patients in liver failure. Leboulch is also a researcher at Massachusetts Institute of Technology in Cambridge.
Leboulch collaborated on the study with colleagues at Okayama University Medical School in Okayama, Japan, and the University of Nebraska Medical Center in Omaha.
- Researchers are developing genetic therapies that can buy more time for liver patients as they wait for an available donor organ or until they can heal on their own.
- Some therapies aim to slow the progression of liver disease by restoring normal genetic function to the organ.
- Other therapies try to extend the life of healthy liver cells so that liver function can continue.