As the fourth-leading cause of death in developed countries, diabetes can truly be called a modern-day plague.
While insulin injections help stabilize the condition, they do not provide a cure. Transplantation of insulin-producing islet cells from human donors or cadavers, an investigational approach to long-term diabetes treatment, is fraught with difficulties. San Diego-based MicroIslet, Inc. believes that transplantation of encapsulated islets from pigs may be the answer. The company has demonstrated proof of principal of this idea through multiple animal studies, and is set to begin human clinical trials of its revolutionary technology this year.
At the recently completed Global Diabetes Summit in Columbus, OH (Nov. 29-Dec. 1, 2007), MicroIslet's President and Chief Scientific Officer, Dr. Jonathan Lakey, explained the potential for treating diabetics with pig islet cells. “Xenotransplantation [from one species to another] has the potential to solve many of the problems associated with the transplantation of islet cells from one human to another,” he said. Dr. Lakey presented compelling animal data from his company's preclinical studies and outlined the likely scenarios under which pig islets could one day emerge as a significant treatment modality for type 1 diabetes.
Diabetes has become a global epidemic with a huge economic impact. More than 194 million people worldwide have diabetes. About 10% of them have type 1 diabetes, which typically arises early in life and requires insulin injections several times a day. The International Diabetes Foundation estimates that diabetes care consumes 10% of the global healthcare budget – $132 billion in the U.S. alone. Most of that cost goes toward treating a dizzying array of serious, often life-threatening complications that include kidney failure, blindness, and poor circulation that can lead to a loss of limbs.
Despite advances, insulin therapy is clearly not the optimal answer to treating diabetes. A healthy pancreas produces insulin only when it is needed, and in just the right quantities, in response to subtle biological signals. Diabetics measuring insulin doses in a syringe can only approximate this complex mechanism. Accordingly, even with strict monitoring, many diabetics succumb to some of the diabetes complications listed earlier.
An experimental surgical technique known as islet cell transplantation has been successfully used to restore the body's insulin-producing capabilities. The operation involves harvesting insulin-producing islet cells from the pancreas of an organ donor and injecting them into the portal vein, or the interperitoneal cavity. Transplanted cells take up residence and, if all goes well, the cells begin to make insulin in response to ingestion of sugars and starches, similarly to how a normal pancreas operates.
Islet cell transplantation has met with limited success for several reasons. Because the body recognizes transplanted cells as “foreign” it tries to eliminate or “reject” them, which is seen in the transplantations of kidneys, livers, and other organs. Patients receiving islet cell transplants must therefore take anti-rejection drugs for the rest of their lives – or the life of the transplant. The tradeoff in reducing or eliminating insulin is the need to take immunosuppressive drugs. For this reason, islet cell transplants are currently only given to patients who cannot control diabetes or its complications through insulin injections, or who are already undergoing organ transplantation due to diabetic complications.
Another problem with islet transplants is the lack of availability of quality human pancreases. The donor organ shortage is compounded by the relatively low abundance of islets among pancreatic cells. Often two organs are needed to obtain sufficient cells to make the transplant work.