For the first time, encapsulated pancreatic cells derived from stem cells — implanted in people with type 1 diabetes — have been shown to produce insulin in response to meals, according to new studies published in the journals Cell Reports Medicine and Cell Stem Cell.
While these new study results are promising, they also highlight several barriers that remain to creating an effective stem cell–derived therapy for people with type 1 diabetes — a type of therapy that many researchers believe could one day replace insulin injections or infusions, as the implanted cells respond to the body’s insulin needs just as a healthy pancreas would do. Just a few weeks ago, a separate study found that stem cell–derived pancreatic islet cells — infused into a single person with type 1 diabetes — reduced that person’s external (injected) insulin requirements by more than 90%, and led to a drop in A1C (a measure of long-term blood glucose control) from 8.6% to 7.2% after 90 days. Stem cell-based therapies have also shown promise for improving blood glucose control in people with type 2 diabetes, and for the treatment of diabetic foot ulcers. But as the new study results show, these therapies are still, in many ways, in their infancy.
To get cutting-edge diabetes news, strategies for blood glucose management, nutrition tips, healthy recipes, and more delivered straight to your inbox, sign up for our free newsletters!
For the research published in Cell Reports Medicine, 17 people with type 1 diabetes — ages 22 to 57 — had a “macroencapsulation device” implanted under their skin. This device contained stem cell-derived pancreatic endoderm cells, which can grow and mature into different types of pancreatic cells. The encapsulation device — sort of a pod containing the cells — was designed to allow for the easy movement of molecules in and out, which meant that participants had to take drugs to suppress their immune system to prevent it from attacking the implanted cells. This “open” design of the device, though, was important to allow blood vessels to grow and attach to it, allowing for the transfer of any insulin produced by the cells into the bloodstream.
Benefits, challenges related to stem cell implants
Between three and 12 months after the implantation of the devices containing pancreatic cells, engraftment — connection to blood vessels — and insulin secretion from the cells were seen in 63% of participants. Out of the 17 participants, six showed evidence of insulin secretion within the first six months. Evidence of insulin secretion was based on levels of a substance called C-peptide, which is secreted along with insulin from pancreatic cells, since it’s generally impossible otherwise to distinguish between injected insulin and internally produced insulin.
For the research published in Cell Stem Cell, the same kind of implanted device was evaluated in 15 people with type 1 diabetes — ages 36 to 56 — over the course of a year. Overall, participants needed to inject about 20% less insulin following the implantation, with one person seeing a greater than 50% reduction in insulin requirements. While participants saw slight improvement in the amount of time spent in their target blood glucose range, no one was able to stop taking external insulin, and several participants experienced severe side effects — with two people withdrawing form the study after experiencing events like infections and liver problems that may have been related to taking immune-suppressing drugs.
While these results show that stem cell-derived pancreatic cells hold enormous promise for future diabetes treatments, they also show that current treatments — which require taking immune-suppressing drugs — carry significant risks and downsides, and may not be appropriate for most people with type 1 diabetes. But if technology can be effectively developed to create a membrane that protects implanted pancreatic cells from an immune system attack — something many researchers are trying to do, including those involved with the single-person study from a few weeks ago — then it may finally, one day, be possible for people with type 1 diabetes to receive a long-term implant or infusion that replaces taking insulin multiple times each day.