New Technique Tracks Pancreatic Islet Survival

FRIDAY, Sept. 22 (HealthDay News) -- Using magnetic resonance imaging (MRI) with an approved contrast agent may help scientists track whether transplanted pancreatic islets survive, say Massachusetts General Hospital researchers.

Pancreatic islet transplants are currently being investigated as a way to treat or cure people with type 1 diabetes, a condition in which the body's immune system attacks its own insulin-producing islets.

The problem is that a significant amount of the islets are usually lost following transplantation, due to a number of factors, including immune rejection and damage to the islets during transplantation.

In a new study, published in the September issue of Diabetes, researchers transplanted islets into the livers of mice. The islets had been marked with Feridex, a U.S. Food and Drug Administration-approved contrast agent.

Some of the mice had normal immune systems, and some had an immune deficiency that would practically eliminate the rejection process.

The researchers used MRI for 14 days after the transplant procedure to track the labeled islets and find out how many were surviving.

For both groups of mice, the number of islets dropped during the first 10 days after the transplant, presumably due to damage during the transplantation procedure. But by day 10, the mice with normal immune function showed a 20 percent greater loss of islets than the immune-deficient mice, most likely due to immune rejection of the islets.

"Monitoring islet survival by noninvasive imaging could give us the ability to detect and measure rates of islet loss under a variety of conditions, which could help develop procedures leading to better therapeutic outcomes," study leader Anna Moore, of the Martinos Center for Biomedical Imaging at Massachusetts General Hospital, said in a prepared statement.