Feb. 15 (HealthDay News) -- Scientists have shown that transplanting healthy liver cells into mice with hemophilia enables the animals to produce a critical clotting factor missing in humans with type A hemophilia.

The breakthrough finding may lead the way to a cure for type A hemophilia, the most common type of the disease, researchers believe.

"We were able to verify what cell type in the body can make factor VIII, which is deficient in hemophilia A," said lead researcher Dr. Sanjeev Gupta, a professor of hepatology at Albert Einstein College of Medicine in New York City.

"In addition, we were able to replace the cells that line the liver and, in that way, we were able to cure the disorder in mice," Gupta said.

In the study, Gupta's team worked with a mouse model of hemophilia. They transplanted healthy liver endothelial cells into the livers of these mice, according to the report in the Feb. 14 online issue of the Journal of Clinical Investigation.

Three months after transplanting the cells, the number of healthy cells had increased and were producing factor VIII in amounts sufficient to cure their hemophilia, the researchers found.

Given these results, researchers can start to focus on where factor VIII is made in the human body and how things can go wrong with its production, Gupta said.

"From the treatment point of view, we can now begin to direct our attention to these particular cells and find the most effective way to cure this disorder in people," Gupta said.

There are several different ways to treat hemophilia A, Gupta said. These include injecting the missing clotting factor, replenishing blood from time to time, or correcting the gene through gene therapy or cell transplantation.

"What we have done in this work seems to be more promising than any of the other modalities," Gupta said. "This is the first time a cure has been achieved with cell therapy. That opens up new directions in treating the condition."

Hemophilia A affects one in 10,000 males and can cause uncontrolled bleeding that can lead to disability or death. It has commonly been associated with British and Russian nobility but affects many others. Cures for hemophilia have ranged from faith healing by the Russian monk Rasputin in the early 20th century to clinical trials using gene therapy, but none of these approaches have amounted to a cure.

One expert thinks a lot more study is needed before this technique can be tried in patients.

"If successful in other animal models, this approach could add another option of treatment for patients with severe hemophilia, though one would have to weigh the risk-benefit ratio," said Dr. Prasad Mathew, from the Ted R. Montoya Hemophilia Center at the University of New Mexico.

SOURCES: Sanjeev Gupta, M.D., professor, hepatology, Albert Einstein College of Medicine, New York City; Prasad Mathew, M.D., Ted R. Montoya Hemophilia Center, University of New Mexico, Albuquerque; Feb. 14, 2008, Journal of Clinical Investigation, online