THURSDAY, May 6, 2010 (HealthDay News) -- Pancreatic cells from pigs that have been encapsulated have been successfully transplanted into humans without triggering an immune system attack on the new cells.
What's more, scientists report, the transplanted pig pancreas cells quickly begin to produce insulin in response to high blood sugar levels in the blood, improving blood sugar control in some, and even freeing two people from insulin injections altogether for at least a short time.
"This is a very radical and new way of treating diabetes," said Dr. Paul Tan, CEO of Living Cell Technologies of New Zealand. "Instead of giving people with type 1 diabetes insulin injections, we deliver it in the cells that produce insulin that were put into capsules."
The company said it is slated to present the findings in June at the American Diabetes Association annual meeting in Orlando, Fla.
The cells that produce insulin are called beta cells and they are contained in islet cells found in the pancreas. However, there's a shortage of available human islet cells. For this reason, Tan and his colleagues used islet cells from pigs, which function as human islet cells do.
"These cells are about the size of a pinhead, and we place them into a tiny ball of gel. This keeps them hidden from the immune system cells and protects them from an immune system attack," said Tan, adding that people receiving these transplants won't need immune-suppressing drugs, which is a common barrier to receiving an islet cell transplant.
The encapsulated cells are called Diabecell. Using a minimally invasive laparoscopic procedure, the covered cells are placed into the abdomen. After several weeks, blood vessels will grow to maintain the islet cells, and the cells begin producing insulin.
The company recently released data from its initial safety trial. The study included eight people with difficult-to-control type 1 diabetes; the volunteers were between the ages of 21 and 68.
Half of the group underwent three transplant procedures, two had two transplant surgeries and the final two had just one transplant surgery, according to information provided by Living Cell Technologies.
The researchers have been following-up on the transplant recipients for about two years. No serious adverse events have been reported to date. Two people said they had abdominal discomfort after the procedure for up to five days. No one has had any immune system reactions to the transplants.
Two people were able to stop taking insulin injections -- one for four weeks, the other for 32 weeks, according to Tan. Others have reduced their daily need for insulin and after 18 months post-implant, all saw their A1c levels (a measure of long-term blood sugar control) improve.
The next stage of trials has already begun, and Tan said the researchers are already seeing improvements in hypoglycemia unawareness in addition to better blood sugar control. Hypoglycemia unawareness is a complication of longstanding type 1 diabetes, and it occurs when people no longer develop a physiological response to low blood sugar levels, such as hunger, headache or sweating. It's a very serious and life-threatening complication.
Tan said with the current trial, which is being funded in part by the Juvenile Diabetes Research Foundation (JDRF), the researchers hope to figure out what the optimal transplant dose should be. And, then, he hopes they'll move on to Phase 3 clinical trials within the next few years.
What isn't yet clear is how long the encapsulated cells will last, and whether or not people will need repeat transplants, much like booster shots are needed for some immunizations.
"If you can replace the beta cells, you can have a dramatic impact on type 1 diabetes. The two things that have stopped beta cell transplants from being a win are the use of immunosuppression drugs and the shortage of human islet cells, and Diabecell really addresses both of those issues," explained Julia Greenstein, director of beta cell therapies for the JDRF.
More information
To learn more about islet cell transplantation, visit the American Diabetes Association.
