Islet transplantation is an experimental surgical procedure that helps to ease or completely stop the symptoms of type I diabetes. It involves harvesting specialized types of pancreatic islet cells from a deceased donor and infusing them into a diabetic patient's liver. Once the islet cells are in place, they begin producing natural insulin. Research on the efficacy and safety of islet transplantation is limited, but many doctors believe that the procedure could eventually become the best available diabetes treatment.
Groups of pancreatic cells called the islets of Langerhans are responsible for producing insulin hormones and specialized digestive enzymes. A person with type I diabetes has defective islets of Langerhans, which impairs the body's ability to break down and use glucose sugar for energy. Currently, most patients need to receive daily insulin injections to avoid serious health complications. A successful islet transplantation can eliminate the need for insulin shots and prevent symptoms from ever returning.
Donor islet cells are isolated and removed from pancreatic tissue using a collagenase enzyme solution. Collagenase breaks tissue apart so that clusters of islets can be extracted with a needle. A surgeon places the freshly harvested cells in a sterile catheter and prepares them for transplantation.
Before the procedure, the patient is given a localized anesthetic in his or her upper abdomen and asked to lie down on the operating table. With the aid of a guide needle and real-time ultrasound imaging, the catheter is inserted into a large blood vessel in the abdomen called the hepatic portal vein. Islets that are infused into the portal vein travel to the liver where they attach to the linings of smaller blood vessels. Once the cells are in place, they begin producing new insulin that travels via the bloodstream throughout the body.
Islet transplantation surgery can usually be performed in about one hour, but a patient typically needs to stay in the hospital for several days following the procedure so doctors can monitor recovery. Frequent blood tests are used to determine if the islets are indeed producing enough insulin to end the need for regular injections. The risks associated with surgery are minimal, but blood clots or internal hemorrhaging are possible. If complications arise, additional surgeries or medical care may be needed.
Clinical researchers and medical professionals have been refining islet transplantation since the 1970s. The procedure shows great promise, but certain issues still exist that prevent it from becoming a mainstay of diabetes management. Patients need to take immune system-suppressing drugs before, during, and after transplantation to ensure their bodies do not reject the new islet cells. When the immune system is compromised, even minor infections or injuries could become life-threatening. Ongoing research hopes to discover a way to perform the surgery without relying on dangerous immunosuppressive agents.
