The liver is the body's chemistry set. It builds complex biomolecules we need, and it filters and breaks down waste products and toxic substances that might otherwise accumulate to dangerous levels. Unlike most other organs, a healthy liver can regenerate itself to a significant extent. But this capacity cannot overcome acute liver poisoning or damage from chronic alcoholism or viral hepatitis.
Acute liver failure from acetaminophen alone takes about 500 lives annually and accounts for close to 60,000 emergency-room visits and more than 25,000 hospitalizations annually. Other environmental toxins, including poisonous mushrooms, contribute still more cases.
All aspects of the new fat-to-liver technique are adaptable for human use, said Gary Peltz, MD, PhD, professor of anesthesia and the study's senior author. Creating iPS cells requires introducing foreign and potentially carcinogenic genes. But adipose stem cells merely have to be harvested from fat tissue. The process takes nine days from start to finish -- fast enough to regenerate liver tissue in acute liver poisoning victims, who would otherwise die within a few weeks, barring liver transplantation.
Some 6,300 liver transplants are performed annually in the United States, with another 16,000 patients on the waiting list. Every year, more than 1,400 people die before a suitable liver can be found for them. While it can save lives, liver transplantation is complicated, risky and, even when successful, fraught with aftereffects. Typically, the recipient is consigned to a lifetime of taking immunosuppressant drugs to prevent organ rejection.
"We believe our method will be transferable to the clinic," Peltz said. "And because the new liver tissue is derived from a person's own cells, we do not expect that immunosuppressants will be needed."