New Culture System Leads To Anti-Viral Treatments For Hepatitis C

A new way of growing viruses in the laboratory developed by Japanese researchers could spell hope for the 170 million people infected with hepatitis C, only half of whom currently respond to drug treatments, scientists announced today (Tuesday 27 March 2007) at the Society for General Microbiology's 160th Meeting at the University of Manchester, UK, which will run from 26 29 March 2007.


"Until now we have been unable to grow hepatitis C virus in the laboratory, which has delayed our development of new treatments. Now, thanks to the system from Japan, we can explore the full life-cycle of the virus", says Dr Stephen Griffin from the University of Leeds, UK.


The scientists have identified a key protein which helps the viruses grow, called p7, by transporting molecules across membranes. A drug targeting a similar protein in the influenza virus was one of the first licensed anti-viral treatments. The Leeds research team has discovered that while the hepatitis viruses are growing, the same protein is crucial for stabilising new virus particles. This offers the hope that blocking its action could provide a new and effective way of combating hepatitis C.


Hepatitis C is now the leading cause of liver transplant surgery in developed countries. No vaccine is currently available to prevent the infection, and contamination through infected blood or other body fluids often happens without any obvious symptoms. This leaves many patients unaware that they have the disease until many years later when they develop liver disorders. Around one fifth of hepatitis C sufferers develop cirrhosis, and 5% will get liver cancer, leading to nearly 2 million deaths worldwide every year.


The current treatments are administered similarly to ones used for HIV, with doctors giving dual drug therapies to target different stages of the virus life-cycle in an attempt to overcome its natural drug resistance.


The new laboratory culture system will allow scientists to study the complete virus life-cycle, including how it builds new virus particles and how these in turn infect new cells.


"We have shown that the p7 protein can form seven sided pores in the cell membranes and alter acidity within the liver cells. We think this is crucial in forming new virus particles, so it is an ideal target for new types of drugs", says Dr Stephen Griffin. "A drug called amantadine, which can be used successfully by doctors against influenza infections, specifically blocks the action of p7. Encouragingly, some clinical trials of amantadine used alongside current treatments have improved patients' response. New drugs based on amantadine offer exciting possibilities for the future treatment of hepatitis C.


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