PITTSBURGH, March 16, 2015 - It might be possible to heal cirrhotic liver disease by rebooting the genes that control liver cell function, according to researchers at Children's Hospital of Pittsburgh of UPMC and the University of Pittsburgh School of Medicine. If validated in human studies, the game-changing strategy, described today in the online version of the Journal of Clinical Investigation, could potentially treat patients who are too sick for liver transplantation and, in the future, reduce the need for transplants.
The project grew out of the observation that not everyone who develops cirrhosis, or scarring of the liver, progresses to liver failure and its life threatening complications, explained Ira Fox, M.D., professor of surgery, Pitt School of Medicine, and director of the Center for Innovative Regenerative Therapies at Children's Hospital and the McGowan Institute for Regenerative Medicine.
"Even with the large amount of scar tissue that comes with cirrhosis, there should be enough cells left to carry out the normal functions of the liver," Dr. Fox said. "So when the liver fails, it is the liver cells themselves that aren't working properly. In this study, we demonstrate what has caused the problem, and more importantly, a way to repair it."
His team developed a rat model of liver disease that mimics the form of human cirrhosis that progresses to organ failure. In previous work, they found that liver cells taken from animals with cirrhosis, but no liver failure, immediately functioned properly when transplanted into another animal. But cells transplanted from animals with both cirrhosis and liver failure did not function normally at first, indicating that both the liver cells and the liver tissue environment were damaged.
The researchers then compared the genes in the liver cells of the two groups of cirrhotic rats and found unusually low activity levels of the genes that control proteins which play a central role in liver cell function, the most important being a factor called HNF4.
In the new paper, they showed that restoring production of HNF4 by gene therapy reboots the liver cells to normal function. The team first showed this in lab tests and then in rats with liver failure.
"We were pleased to see that the animals got better almost immediately. Remarkably, our tests indicated that it wasn't stem cells, regeneration or growth of new liver cells that caused improvement. Instead, the diseased cells had healed," Dr. Fox said. "It seems that in at least some forms of cirrhosis, chronic injury reprograms the liver cells to shut down HNF4 production, a dysfunction that eventually causes liver failure."
HNF4 gene therapy provided unique insight into the cause of liver failure and has significant potential for human therapy, but the investigators are now looking for other gene targets to develop simpler therapies, such as drugs that block the pathways that mediate failure. The team also is confirming their results with human liver cells.
Co-investigators include Alejandro Soto-Gutierrez, M.D., Ph.D., Joseph Locker, M.D., Ph.D., and other researchers from Children's Hospital, Pitt School of Medicine and the McGowan Institute; Kyoto Prefectural University of Medicine, Japan; and the University of Pennsylvania.
The project was funded by National Institutes of Health grants DK48794, DK099320 and DK099257, as well as grants from the U.S. Department of Defense.
About Children's Hospital of Pittsburgh of UPMC
Regionally, nationally, and globally, Children's Hospital of Pittsburgh of UPMC is a leader in the treatment of childhood conditions and diseases, a pioneer in the development of new and improved therapies, and a top educator of the next generation of pediatricians and pediatric subspecialists. Children's Hospital has fulfilled this mission since its founding in 1890. Children's is named consistently to several elite lists of pediatric hospitals, including ranking 7th among children's hospitals and schools of medicine (FY 2013) in funding for pediatric research provided by the National Institutes of Health, and is one of 10 pediatric hospitals in the United States named to U.S. News & World Report's Honor Roll of America's "Best Children's Hospitals" for 2014-2015.
About the University of Pittsburgh School of Medicine
As one of the nation's leading academic centers for biomedical research, the University of Pittsburgh School of Medicine integrates advanced technology with basic science across a broad range of disciplines in a continuous quest to harness the power of new knowledge and improve the human condition. Driven mainly by the School of Medicine and its affiliates, Pitt has ranked among the top 10 recipients of funding from the National Institutes of Health since 1998. In rankings recently released by the National Science Foundation, Pitt ranked fifth among all American universities in total federal science and engineering research and development support.
Likewise, the School of Medicine is equally committed to advancing the quality and strength of its medical and graduate education programs, for which it is recognized as an innovative leader, and to training highly skilled, compassionate clinicians and creative scientists well-equipped to engage in world-class research. The School of Medicine is the academic partner of UPMC, which has collaborated with the University to raise the standard of medical excellence in Pittsburgh and to position health care as a driving force behind the region's economy. For more information about the School of Medicine, see http://www.
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