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The future of islet transplants: supplied by stem cells and free of immune suppression?

Published on Aug 7, 2025

Islet transplantation has been a management option for Canadians with type 1 diabetes (T1D) in the 21st century because of the success of the Edmonton Protocol for transplantation. During the procedure, people living with T1D get an infusion with islets containing insulin-producing beta cells from compatible deceased donors. Many people are able to be free from insulin injections for some time following the transplant. 

While transplants have been very positive for many people with T1D, there are a few important drawbacks:

  1. The number of transplants is severely limited by the number of available pancreases from deceased donors. Currently, to be considered for a transplant, a person has to face significant hurdles in managing their blood sugar; for example, recurrent hypoglycemic coma despite intensive support.
  2. Transplants require lifelong immune-suppression medications which increase health risks (e.g. susceptibility to infection) and therefore reduce how many people are eligible and willing to undergo transplants. 

Addressing these drawbacks may make islet transplantation an option for the broader T1D community in the future. Two major breakthroughs, which address these key issues, have recently been shared: 

1- Stem cells may be the solution to meet transplant demand

Stem cells have the potential to become other cells and production of them can be scaled up to allow transplants for more people without continued requirement of donors. With careful treatment, stem cells can be coaxed into becoming insulin producing cells and used as a non-limited source for transplantation. 

  • Former stem cells can regulate blood sugar

In a recent breakthrough study, participants received 800 million insulin producing cells made from stem cells. At the start of the study, all participants were insulin dependent, had impaired awareness of hypoglycemia (significantly reduced or no symptoms at the time of hypoglycemia), and experienced at least 2 severe (< 3 mmol/L) hypoglycemias in the past year. All 12 that made it to the end of the study had an HbA1c less than 7% and reduced insulin dose; at day 365, 10 participants were completely insulin independent. Time in target glucose range was greatly improved, on average 50% at the beginning of the study and over 93% by the end. 

  • Stem cell-derived transplants require immune-suppression

While there were common adverse events, the events were considered mild to moderate with the most common being diarrhea and headache. Importantly, this stem cell transplant still requires immune-suppression medication which is likely the cause of lower white blood cell count and worsened kidney function in participants. Unfortunately, 2 participants died during the course of this study, at 19 and 30 months post-islet transplant. These deaths were not linked to the procedure but one is likely linked to the immune suppression. Larger studies with longer term follow-up are required to better understand the risks and benefits of this procedure but it is still a major step in the direction of a possible cure.  

Another study tried to shield the same stem cell derived islets from the immune system using encapsulation. The encapsulation device was intended to protect islets from rejection or recurrence of autoimmunity while allowing cells to sense glucose and release insulin outside of the device into the blood stream. A recent trial using this approach showed it was safe, but failed to show insulin secretion, so the trial was stopped.

2 – Cell editing can help transplants avoid rejection

Another research group is tackling the issue of immune suppression using a different approach. A recent press release gave a 6-month update for the first transplant done without immune suppressant medication. They took islets from a deceased donor, used gene editing (i.e., deleting/modifying genes related to immune attack or tolerance) to avoid immune detection, and injected the edited “hypoimmune” cells into one participant’s forearm. In the 6 months since the transplant, the transplanted cells have survived, the participant has detectable c-peptide (a surrogate marker for insulin), and the c-peptide levels increase in response to a meal. 

  • One (suppression-free) transplant done, many to go

While this immune-suppression free transplant is very exciting, this study so far has only included one person and was limited for safety as a first trial. Future studies will need a much larger dose of cells to potentially achieve insulin independence, may need to trial other transplant sites, and will require many more participants to back up the current data. But, this proof of concept sets the stage for continued evolution toward a future of immune-suppression free islet transplantation.

Better together? Combining stem cells and immune evasion

The future of islet transplants may very well combine these techniques by gene editing stem cells, thus reducing complications of immune suppression and increasing the limited material available for transplant. Together, these advancements could mean transplants for more people with lower risks and transplants becoming available for people for whom immunosuppression was not a good option. 

 

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Written by: Cassandra Locatelli, research assistant

Reviewed by:

  • Rémi Rabasa-Lhoret, MD, PhD
  • Pamela Dawe, Roberta Ferrence, Darrin Davis, patients partners 

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