What Are the Pancreatic Islets?
The pancreas is an organ located just under the stomach that produces metabolic hormones and digestive juices. Among the tissues of the pancreas are the islets of Langerhans, which produce hormones. The majority of the cells in the islets are beta cells, which produce the hormone insulin.
In type 1 diabetes, the immune system attacks and destroys the beta cells in the islets of Langerhans. This results in an inability to produce insulin. In type 2 diabetes, insulin is still produced, but in later stages of the disease, insulin production often decreases. Diabetes treatments for these patients normally include artificial insulin therapy, but transplantation is becoming a reality for some diabetics.
Whole Pancreas Transplants
Especially with type 1 diabetes, artificial insulin treatment is not always enough to prevent complications from progressing. Insulin injections simply are not sufficient to completely normalize the metabolism of patients who cannot produce their own insulin (Press 2004). Whole-pancreas transplants are an option for patients who continue to experience severe swings in blood sugar despite insulin therapy (UMMC 2008).
Over 20,000 whole-pancreas transplants have been performed worldwide, with a one-year success rate of about 80% (Press 2004). Transplanting a whole pancreas requires major abdominal surgery. A new technique that attaches the pancreas to the portal vein and the small intestine began to be used around 2002. This method reduced hospital stays, but was still a major operation (Creager 2002).
Pancreatic Islet Transplantation
Type 1 diabetics normally have healthy pancreases with the exception of the beta cells, which make up only 2% of the total pancreas cells (Press 2004). It makes sense, therefore, to transplant only the islets of Langerhans as a diabetes treatment. This procedure can be done by injecting the cells directly into the pancreas, avoiding the need for major surgery.
In 2000, Dr. James Shapiro developed a new technique called the Edmonton Protocol for pancreatic islet transplantation. His protocol dramatically improved success rates for islet transplantation (Press 2004). This technique involves the use of two or more donors to increase the number of islet cells injected. Unfortunately, the use of multiple donors reduces the number of transplants that can be done and increases the cost of the procedure.
In 2005, the Journal of the American Medical Association announced that Dr. Bernhard Hering and colleagues had transplanted islet cells from single donors into eight women with type 1 diabetes. Five remained insulin-independent after one year, a much better success rate than had previously been achieved with single-donor islet transplantation. Further research may make pancreatic islet transplantation a routine treatment for type 1 diabetes and perhaps even for type 2 diabetes with reduced insulin production.
- Creager, Ellen, 2002. “New transplant a breakthrough: Simpler surgery on pancreas aids Type 1 diabetics.” Chicago Tribute. https://islet.org/forum026/messages/24324.htm
- Journal of the American Medical Association News Release, February 15, 2005. “Single-donor pancreas islet transplantation procedure shows promise for patients with type 1 diabetes.” https://pubs.ama-assn.org/media/2005j/0215.dtl
- Press, M., 2004. “Pancreatic islet transplantation.” Endocrine Abstracts 7 S38 — https://www.endocrine-abstracts.org/ea/0007/ea0007s38.htm
- University of Maryland Medical Center (UMMC), 2008. “Indications and Contraindications: Pancreas Transplant.” https://www.umm.edu/transplant/pancreas/indpanc.htm