Pancreas and Islet Transplants
Dec 27, 2016
Pancreas and islet transplants are most often performed in people with Type 1 diabetes. Since the 1960s, pancreas transplants have been performed almost exclusively in these cases, but more recent research has led to the use of islet transplantation. Both procedures have benefits and drawbacks, and both have several alternative approaches.
A complete or partial pancreas transplant is generally performed in people with life-threatening conditions related to Type 1 diabetes, such as hypoglycemic unawareness, end-stage kidney disease, or brittle diabetes. A properly functioning pancreas, obtained either whole from a deceased donor or partially from a consenting live donor, is often transplanted at the same time as an accompanying healthy kidney, since a single surgery involves less risk than two separate procedures. The new pancreas is usually transplanted in addition to the existing pancreas instead of as a replacement, since the transplanted pancreas may fail. This failure is most often due to the patient’s own immune system recognizing the new pancreas as a foreign body.
Pancreatic islets contain beta cells that produce insulin. In people with Type 1 diabetes, these beta cells no longer function because their bodies’ immune systems have reacted to them as foreign bodies and destroyed them. To restore proper pancreatic function–producing the insulin that allows the absorption and effective use of blood glucose–functioning islet cells are sometimes transplanted into the patient’s body. This procedure is either 1) allotransplantation, or 2) auto-transplantation.
Allo-transplantation is carried out by surgically inserting islet cells from deceased organ donors into a patient’s pancreas. These islets have been extracted from the donor and then purified before transplantation occurs. Within hours, these islet cells begin producing insulin, though it may take some time for them to work as efficiently as they should. Risks of this procedure include the typical risks of any major surgery–blood clots, uncontrolled bleeding, reaction to anesthesia, etc.–but also carry the risk of secondary infections since the immune system must be greatly suppressed to reduce the occurrence of tissue rejection.
Auto-transplantation is used only when the patient’s pancreas has been completely removed. This procedure is most often called for when the patient has reached the stage where their pancreatitis has become unmanageable. The patient’s own islets are purified and then introduced into the liver. The islets may then produce enough insulin for the patient to regulate blood glucose. Since the islet cells belong to the patient, the risk of rejection is low. (Because this requires functioning insulin-producing beta cells, auto-transplantation is not available to patients with Type 1 diabetes.)
Artificial Pancreas Research
At least three avenues of research are being carried out to create an artificial pancreas. A mechanical solution, such as an insulin pump, requires the continual sensing of blood glucose levels and the dispensing of an appropriate insulin dosage. The gene therapy approach has several options. One is to prompt adult stem cells in the duodenum to become self-replenishing beta cells which would then produce the insulin needed. A third approach is a biological one. Islet cells, protected by encapsulating them in a gel, are implanted as a mesh fiber sheet into the patient.
Research into pancreas and islet cell transplant requires the knowledge and skills provided by a contract research organization like PMI. In addition to the medical research expertise and experience necessary to carry out reliable, robust studies, a CRO offers specific and in-depth knowledge regarding state and federal regulations, documentation, and data archival.