Insulin producing stem cells effective when implanted under skin

Transplantation of insulin producing islet cells under the skin offers an alternative method of islet cell transplantation that removes a number of the current difficulties associated with conventional methods.
The research was carried out by a research team from Sanford-Burnham Medical Research Institute and the University of California, San Diego School of Medicine. Islet cell transplants are a method of treating type 1 diabetes which can allow patients to come off insulin injections or at least significantly reduce their daily insulin doses.
The procedure improves diabetes control and substantially decreases episodes of severe hypoglycemia but is currently a rare treatment because of the current limitations that exist, such as the scarcity of donated islet cells and the requirement for the transplantee to take immunosuppressing drugs.
The conventional procedure involves infusing insulin producing islet cells (beta cells) into the portal vein of the liver. Following the procedure, patients must take immunosuppressive drugs for the rest of their life to prevent the immune system targeting and killing the transplanted cells.
The new process uses human embryonic stem cells (hESC) which are encapsulated in a protective capsule and transplanted under the skin. The protective capsule is designed to prevent the islet cells from the immune system attack of type 1 diabetes without requiring immunosuppressive drugs.
Use of progenitor stem cells also has advantages in that the cells can be grown in the lab and are more robust than mature islet cells from adult donors. The more robust nature of the stem cells means they can withstand being encapsulated before maturing into functional islet cells.
The researchers tested the process in animals and used bioluminescent imaging to monitor whether the islet cells remained within the capsule. The study found that the cells remained fully within the capsule for 150 days. The researchers note the importance that the islet cells do not outgrow their capsule, whilst remaining responsive to changes in blood glucose levels.
In terms of controlling blood glucose levels, the study found that the implanted capsule was indeed effective. The research brings good news. Future research will next need to test what size of capsule is required for human treatment and how long the transplanted cells will be effective for in humans.