Transplanted liver cells can produce insulin

Insulin is produced by islet cells in the pancreas, but scientists have been able to persuade adult liver cells to do the same thing. Moreover, insulin production goes up in response to glucose levels, mimicking what happens in the body.

People with diabetes have been cured with transplants of islet cells, but donor islet cells are scarce. The possibility of using a person's own liver cells instead "may overcome the shortage in tissue availability from cadaver donors and the need for lifelong immune suppression," said Dr. Sarah Ferber.

Ferber, from The Endocrine Institute in Tel-Hashomer, Israel, and colleagues took a gene, PDX-1, that's active in the pancreas and duodenum and transferred it to human liver cells, using a virus to carry the gene into the cells.

As many as half the infected adult and fetal liver cells became able to store and secrete insulin, the team reports in the Proceedings of the National Academy of Sciences, Early Edition.

PDX-1 liver cells not only produced, stored and secreted insulin in a glucose-regulated manner, but also lessened Diabetes when implanted in diabetic mice.

The technique "represents a novel approach in tissue engineering," Ferber said. "It allows ... these tissues to acquire a new identity and function, without altering the original genetic information."

Therefore, this approach "allows the diabetic patient to be also the donor of his own therapeutic tissue," Ferber explained. However, she anticipates initial experiments in humans won't take place for several years.

SOURCE: PNAS Early Edition, May 16, 2005.