Hepatitis breakthrough at UW

University of Washington scientists have devised a unique way to grow the hepatitis C virus in the laboratory — an important step in the quest for a vaccine and improved treatment for what has become one of the most widespread infectious diseases in the world.

The researchers for the first time were able to keep the virus reproducing for at least two months, enabling it to infect liver cells, where it does its devastating work.

"We'll be able to better see what damage is done to cells, and it will provide a way to test antiviral agents ... and help develop a vaccine," said Dr. Nelson Fausto, chairman of the UW department of pathology, who directed the research.

Hepatitis C infects about 170 million people worldwide, including more than 4 million in the U.S. The virus is carried in the blood and is usually spread by contaminated needles during drug abuse. It is also spread, rarely, by sex, by an infected mother to her child, or by other contact with infected blood.

The disease becomes chronic in the majority of patients. After 20 to 30 years, about one-fifth of them have liver scarring that can lead to cancer. Hepatitis C liver disease is the leading reason for patients needing a liver transplant.

Fausto and his UW colleagues made headlines last June as the first scientists to isolate human liver stem cells, which are the ancestors of all liver cells. The cells were taken from aborted fetuses donated to research, then grown in the lab and infused in mice, where they replaced dead liver cells.

The team now has used the liver stem cells in developing the new lab culture for hepatitis C, which is to be reported in the February edition of The American Journal of Pathology.

It was a tedious process, taking about four years to perfect, Fausto said. But the researchers proved in several ways that the culture is a nourishing home for the virus.

Scientists injected the cells into a culture with genetic material from the virus. The viruses then reproduced into the culture, the culture itself was mixed with more cells, and those cells, too, became infected.

The team also mixed the blood of patients with different strains of hepatitis C into the culture of liver stem cells. Again, the virus thrived and reproduced.

"I think we finally have it," said Fausto. "We can grow this virus in normal [liver cells]."

Other scientists have grown the virus using cancerous liver cells or using a virus from a patient with a rare case of rapidly escalating hepatitis. But neither are typical of real-life infections, Fausto said.

Fausto said the next step in the research is to see whether laboratory animals can be infected with the laboratory-grown viruses. That would further establish the viability of the culture method as a way to study the virus.

Universities and pharmaceutical companies alike have "tremendous interest" in developing a vaccine and more treatments, because hepatitis C affects so many people, Fausto said.

It is difficult research, he said, but he predicted that a vaccine could be developed in about five years, and testing of it completed in a few more years.

Warren King: 206-464-2247 or wking@seattletimes.com