NEW YORK -- Two studies released Thursday could lay the groundwork for new treatments for a number of serious liver diseases, according to researchers.

Their early work with cells and animals points to potential ways to treat hepatitis B infection and liver damage done by alcohol and other toxins.

Reports on both studies appear in the February 7th issue of Science.

In one study, researchers found that a growth factor naturally produced in the body appears to set off a cascade of events that protects the liver from damage. The substance, called vascular endothelial growth factor A (VEGF-A), is produced by cells that line the blood vessels, and is best known for its role in spurring new blood-vessel growth.

But the new findings, gleaned from work with mice and cells, show that VEGF-A is able to spur the release of certain other growth factors from a network of vessels that feed the liver. These growth factors, in turn, trigger a proliferation of liver cells.

Similarly, activation of one of the cell receptors for VEGF-A -- called VEGFR-1 -- also appeared capable of protecting liver cells and initiating liver regeneration.

All of this suggests that a drug that would activate VEGFR-1 -- a so-called VEGFR-1 agonist -- could help prevent liver damage caused by alcohol abuse, certain medications or viral hepatitis, one author told Reuters Health.

"We propose that a VEGFR-1 agonist could be useful in a variety of conditions where one wishes to prevent hepatocyte (liver cell) death," said Dr.

Napoleone Ferrara, a research fellow with the San Francisco biotech company Genentech.

Importantly, he pointed out, VEGFR-1 activation seems to trigger the release of growth factors for liver cells without promoting new blood-vessel formation -- a process called angiogenesis.

This is a concern because abnormal angiogenesis is believed to encourage cancer growth by giving small tumors the blood supply they need to thrive and spread.

In the second study, German and U.S. scientists at Bayer Corp. found that a new class of compounds may fight the hepatitis B virus (HBV) in a way that differs from current medications.

Hepatitis B is a serious liver infection that, for a small percentage of people, can become chronic and lead to permanent liver damage or cancer. A few drugs, including interferon, can treat chronic hepatitis B, but side effects and viral resistance have limited the therapies' success, according to the study authors.

Their work showed that the new class of compounds, known as HAP, can block the formation of the protein coat that normally envelops HBV particles.

Earlier research had already shown that the compounds inhibit human HBV in mice.

"These inhibitors have potential for future therapeutic regimens to combat chronic HBV infection," conclude Dr. Karl Deres and his colleagues.

An estimated 1.25 million Americans have chronic HBV infection. The infection, which is passed mainly through sex or contact with infected blood, can be prevented with the hepatitis B vaccine. (Reuters)