Stem Cell Can Help
CIRM funds many projects seeking to better understand diabetes and to translate those discoveries into new therapies.
Diabetes comes in two forms: type 1 (also known as juvenile) and type 2 (also known as adult). Approximately 1.25 million people in the U.S. have type 1 diabetes, which is the form primarily being targeted by stem cell research.
Type 1 diabetes is an autoimmune disorder where the body’s own immune system destroys the cells in the pancreas that make the hormone insulin. Insulin normally circulates in the bloodstream after a meal and allows cells of the body to take up sugar and use it for food. Without insulin, cells starve and the sugar builds up in the bloodstream where it can damage the kidneys, blood vessels and retina.
Any potential cure for type 1 diabetes requires replacing the lost insulin-producing cells of the pancreas. Currently, the only cells that can be used for such a transplant come from donated organs, which are in short supply. Such insulin-producing cell transplants are also risky because the cells can be rejected by the recipient’s body if they don’t receive immune suppressing drugs.
To solve the first problem, groups of CIRM-funded researchers have developed methods to make replacement insulin-producing cells derived from human embryonic stem cells, which can be grown in large amounts. Implanted into mice and rats these cells are able to regulate blood sugar.
To get around the problem of rejection, CIRM-funded teams have placed donor progenitor cells in a device that implants under the skin and shields the cells from the patient's immune system. Other groups are studying how to regulate the immune system to make stem cell-derived transplants safer.
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Transplantation of beta cells, contained in donor pancreatic islets, can reverse the symptoms of diabetes. However, due to a poor islet survival rate, transplants require islets from multiple donors. Since islet cells are transplanted directly into the vessels that enter the liver, it is extremely difficult to monitor and retrieve these cells should the need arise. Peter Stock and his team at UCSF are using parathyroid glands to aid in the success and viability of the transplant procedure. Co-transplantation of islets and parathyroid glands, from the same donor, substantially increases beta cell survival, potentially enabling adequate long-term insulin production and removing the need for multiple donors. The co-transplantation will occur in the patient’s forearm, which allows for easier monitoring and improves the effectiveness and accessibility of islet transplants for patients.
Caladrius is targeting the immune system as an alternative strategy for treating patients with type 1 diabetes. This disease causes the immune system to destroy the insulin-producing cells of the pancreas. The team is developing a stem cell-based therapy using the patient's own cells. They will take cells, called regulatory T cells (Tregs), from the patient’s own immune system, expand the number of those cells in the lab and enhance them to make them more effective at preventing the autoimmune attack on the insulin-producing cells.
ViaCyte is developing cell therapies to replace lost beta cells for people with type 1 diabetes (T1D). The therapies are derived from human embryonic stem cells, which are partially matured into becoming pancreatic tissues (the type destroyed in T1D). The cells are inserted into a small pouch that is transplanted under the patient’s skin. The transplanted cells will develop into fully matured beta cells that secrete the hormone insulin, which is needed to keep blood sugar levels at a healthy level. CIRM is funding ViaCyte’s two Phase 1/2 trials testing different product candidates. The first product, VC-01, encapsulates the cells and protects them from the patient’s immune system. The second product, VC-02, allows the patient’s blood vessels to make direct contact with the implanted cells. VC-02 is being developed for patients with high-risk T1D.