Study shows promise for implantation of encapsulated islets
In the last several years, beta cell encapsulation research has become a high priority for JDRF. For well over a decade, researchers have been able to restore insulin function to some degree in people with type 1 diabetes (T1D) by transplanting insulin-producing islets recovered from deceased donors. However, the trade-off for these islet recipients is a life-long requirement to take strong drugs that suppress the immune system and prevent it from rejecting the transplanted cells. These powerful drugs are not appropriate for children with T1D and can result in potentially severe side effects. Also, these procedures are available only to people with the most uncontrolled T1D, because of the limited supply of donated islets (from deceased organ donors) and the required immune-system suppression.
The goal of JDRF’s encapsulation research program is to solve both of these limitations by developing materials to protect implanted beta cells from the body’s immune attack and developing new beta cell sources so that these procedures will be available to all who may benefit from them. For people with T1D, achieving this goal would mean they could receive an implant of insulin-producing beta cells that are protected from the immune system, thereby eliminating their dependence on external insulin through a simple procedure.
A study recently published in Proceedings of the National Academy of Sciences provides further demonstration that implanting encapsulated beta cells can be beneficial to individuals with T1D. In the study, researchers led by Stefan R. Bornstein, M.D., Ph.D., at the Carl Gustav Carus University Hospital in Dresden, Germany, implanted functional islet cells from the pancreas of a deceased organ donor into a 63-year-old man who had had T1D for 54 years and who showed no evidence of residual beta cell function. The cells were encapsulated in a specially designed chamber composed of a combination of alginate and other materials and supplied with oxygen (crucial to the cells’ survival). After evaluating the recipient for 10 months following the implantation, the researchers reported two significant results:
1) the patient showed modest increases in C-peptide, indicating that the implanted cells were producing small levels of insulin on their own, and
2) the body’s immune system did not show signs of having destroyed the implanted cells, indicating that the encapsulation device successfully protected the islets, allowing them to survive for the full 10 months of the trial.
These results are significant because they represent the first time that encapsulated human islet cells have been successfully implanted into a person with T1D and maintained their insulin-producing function over a prolonged period of time without the need for drugs to suppress the immune system. This new finding is strong evidence that islet cell encapsulation has the potential to successfully achieve its goals. The combination of the encapsulation material and the oxygen supply seems to have successfully shielded the cells from attack by the body’s immune system and kept them healthy and functioning for almost a year.
While these results are promising, it’s important to note that this study involved only a single patient and led to only modest benefits for the recipient. While his hemoglobin A1c levels and insulin requirements were lowered slightly, he still needed to give himself insulin and test his blood-glucose levels. According to JDRF Vice President of Cure Therapies Julia L. Greenstein, Ph.D., this study is exciting and clearly showed “the ability to maintain some function without immunosuppression.” However, according to Dr. Greenstein, “it’s a study of one patient, and the level of C-peptide wasn’t enough to significantly impact the clinical situation of the recipient.” While the study didn’t meet the goals of normal blood-sugar levels or insulin independence, it’s “one early step on the way to developing a practical approach to providing islet function for a person with type 1 diabetes.”
While JDRF did not fund this particular study, it is consistent with our efforts to achieve insulin independence in people with T1D using implanted encapsulated islets. JDRF has been a leader in this field and has made a significant investment in research to develop effective means to encapsulate islets using alginate and other materials. While these materials and the current study would address the need to protect islets from the immune system, JDRF is taking it a step further and also funding research to address the problem of islet supply. While the current study used islets from a deceased organ donor, that’s not a feasible solution for the larger T1D population, because of the limited availability of such cells. JDRF-funded research using pig islets (xenotransplantation) combined with encapsulation is already showing positive indicators in human trials. And JDRF-funded research using islets derived from stem cells in combination with encapsulation is expected to begin human clinical trials next year. Finally, the recent launch of the JDRF Encapsulation Consortium, which brings together a collaborative group of key players in science, engineering, and medicine to share their research to advance encapsulation technology, ensures that JDRF will continue to drive this promising research forward toward next-generation encapsulation therapies that yield more significant benefits to individuals with T1D.