Less Than $25 in Parts Could Help Create a Better Artificial Liver
March 31, 2000 (San Francisco) -- An off-the-shelf valve that costs $20, a timer for less than $5, and some transistors might make the difference in engineering an artificial liver that can work for months until a patient's own liver is ready to function properly again.
Experimental artificial liver-assist devices are now used to keep patients whose livers are failing due to acute poisoning alive long enough to find organs that can be used for transplants.
But, Pao Chau, PhD, a professor of chemical engineering at the University of California, San Diego, demonstrated this week how a few changes in a current design might give a patient time for his or her own liver to fight off the poison and function on its own.
"That can take several weeks," says Chau, who spoke here Wednesday at the 219th national meeting of the American Chemical Society. "Right now, the devices being used only work effectively for less than two weeks."
A functioning liver allows a person to lead a normal life, but a transplant patient faces a serious surgery, a long recovery, and a lifelong dependence on medication.
But complicating the development of an artificial liver is the fact that the liver performs numerous duties, including replenishing blood cells. "The liver is a difficult organ to replicate," Chau tells WebMD. The artificial liver devices -- including Chau's revised machine -- work outside the body. The devices are filled with liver cells, either from humans or animals, and perform the tasks of the liver as the patient's blood is routed through the cylinder chambers filled with hollow fibers.
According to Chau, the structure of many of these devices leaves a lot to be desired physiologically. In his machine, he says, the addition of a valve to pinch the hollow fibers shut for about three seconds every minute gives the cells a chance to exchange nutrients better than the present device in clinical trials.
Another artificial liver concept, a type of "bioreactor," is now being tested by VitaGen Inc. of La Jolla, Calif. Chau is working with VitaGen to improve the design of the device.