Researchers at Northwestern University this week revealed that they have successfully transplanted insulin-producing cells called islets from one species to another. They believe that this successful interspecies transplant could be the first step toward animal-to-human transplants as a treatment for diabetes. The research was published today in the journal Diabetes.

“This is the first time that an interspecies transplant of islet cells has been achieved for an indefinite period of time without the use of immunosuppressive drugs,” said Stephen Miller, study co-author and a professor of Microbiology-Immunology at Northwestern. “It’s a big step forward.”

Miller and his colleagues successfully transplanted rat islets into mice. The transplant was performed using no long-term drugs to suppress the mice immune system. The islets were not rejected by the mice, and produced insulin for the duration of the study. To accomplish this, researchers took rat white blood cells, called splenocytes, and killed the cells, which were then injected into mice. The immune systems of the mice then learned to accept the cells ahead of the islet transplants. The mice were also given B-cell depleting antibodies at the time of the transplant, allowing the B-cells that returned later to accept the rat islets.

“Our ultimate goal is to be able to transplant pig islets into humans, but we have to take baby steps,” said Dr. Xunrong Luo, co-author of the study and an associate professor at Northwestern’s Feinberg School of Medicine. “Pig islets produce insulin that controls blood sugar in humans.”