New Delhi, April 1: Japanese researchers have reversed liver cirrhosis in rats, demonstrating a unique strategy to deliver a synthetic molecule that helps block the destruction of the organ.

The success with rats has raised hopes that a similar technique might one day be used on patients with advanced liver cirrhosis, an illness for which the only standard treatment today is an organ transplant.

The scientists used a molecule coupled with vitamin A as a Trojan horse to deliver a strand of synthetic genetic material called small interfering RNA (SiRNA) into liver cells that produce collagen — the hard fibrous tissue — in cirrhosis.

The treatment rescued rats from cirrhosis that had been induced with chemicals, Yoshiro Niitsu of the Sapporo Medical University School of Medicine, Hokkaido, and his colleagues reported yesterday in the journal Nature Biotechnology .

“The unique aspect of this work is the elegant targeting strategy they have used to deliver the SiRNA,” said Scott Friedman, a liver expert at the Mount Sinai School of Medicine in New York, who was not associated with the study.

The liver cells that produce collagen in cirrhosis have a natural affinity for vitamin A. By packaging the SiRNA inside a molecule with vitamin A, the researchers fooled the liver cells into accepting SiRNA, leading to a shutdown of collagen synthesis.

But human studies are still years away. “We will need to evaluate toxicity and go through human clinical trials,” Niitsu said. “We’re, perhaps, five years away from applying this in humans.”

Cirrhosis, which affects hundreds of millions of people worldwide, is the result of liver damage caused by alcohol abuse, by viruses such as hepatitis B or C, or by nutritional deficiencies.

Doctors in India estimate that about 200,000 people die from liver failure — mainly from cirrhosis — in the country each year. “For advanced liver cirrhosis, the only option is transplantation,” said Arvinder Soin, a Delhi-based transplant surgeon. “These results are interesting, but we’ll need to wait and see how long it’ll take before it is ready for clinical applications.”

But some researchers believe alternative oral therapies may emerge to compete with this injectible delivery of SiRNA. It is possible that the SiRNA technique could be used only initially, followed by oral therapies for long-term benefit, Friedman said in a commentary on the Japanese results in the same issue of the journal.