So the team set out to develop a technique to keep the liver cells stable and functioning long enough to monitor their response to the virus and antiviral drugs.
They based their approach on a system they had previously developed for studying the hepatitis C virus, in which they were able to successfully infect human hepatocytes with the virus and use it to compare antiviral regimens.
The hepatocytes are first patterned onto surfaces dotted with tiny spots of collagen, and then surrounded by supportive tissue made up of stromal cells, which act as connective tissue and support the hepatocytes in carrying out their liver functions.
Two Complementary Systems
To apply the technique to infection with HBV, the researchers developed two complementary systems. One uses primary hepatocytes obtained from livers donated for transplant; the second uses stem cells derived from human skin samples and guided into hepatocyte-like cells, Bhatia says.
When they compared the relative merits of the two systems, they found that the primary liver cells had a stronger immune response when infected with the virus than the stem cell progeny. However, unlike the primary hepatocytes, the hepatocyte-like cells offer an unlimited supply of test cells, since the researchers can simply grow more as required, Bhatia says.
"But that being said, both systems were able to grow this persistent nuclear form [of HBV], so we think they offer complementary tools," she says.
To investigate whether the cell cultures could be used to test new treatments for the disease, the researchers monitored their response to two existing drugs. They found that the infected cultures responded to the drugs in the same way that liver cells inside the body are
|Contact: Sarah McDonnell|
Massachusetts Institute of Technology