Main Focus of Pancreatic Tissue Engineering
The main focus of pancreatic tissue engineering is the implantation of insulin-producing pancreatic islets into patients who cannot produce their own insulin or who do not produce enough insulin. Islets are obtained from a deceased donor’s pancreas, a living donor’s pancreas, the patient’s own pancreas, or from stem cells. Pancreatic islet implantation is considered by many scientists to be a better alternative than pancreas organ transplant. These scientists consider islet implantation to be equally effective without subjecting patients to a traumatic surgery. Islet implantation is a relatively simple procedure where the islets are injected into a vein in the liver.
Islets obtained from a deceased donor’s pancreas are extracted and isolated using a special enzyme. Because islets are fragile and will not survive long in the laboratory, they are implanted into the patient soon after they are extracted. Two donor pancreases are usually required to obtain enough islets for one patient. The patient has to be put on immunosuppressive drugs to prevent rejection of the islets. Scientists are researching ways to prevent immune responses to the donor islets without the use of immunosuppressive drugs. One big drawback of obtaining islets from deceased donors is the limited availability of viable donor pancreases.
Islets can be obtained from a living donor, usually a family member. Part of the living donor’s pancreas is removed and islets are extracted and isolated from the removed portion using a special enzyme; the islets are then implanted into the patient. Some research has suggested that islets extracted from a living donor tend to be more viable than those extracted from a deceased donor. As with deceased donor islets, the patient needs to be put on immunosuppressive drugs to prevent rejection. Living donor islet transplants cause the donor to go through a traumatic surgery.
A Patient’s Own Islet Cells
Patients who have a partial pancreatectomy due to pancreatitis can have islets extracted from their own pancreas and implanted back into them. In a partial pancreatectomy, part of the pancreas is left in the patient in hopes that it will continue to produce insulin. A large portion of patients who undergo a partial pancreatectomy later develop diabetes. The goal of extracting islet cells from the removed portion of the pancreas is to prevent the patient from developing diabetes. Patients who undergo this procedure do not need to take immunosuppressive drugs because they are receiving their own cells.
Extracting enough viable islets from a diabetic patient can be difficult if not impossible, which is why donor islets are often used. Pancreatic islets obtained from donors require the patient to be put on immunosuppressive drugs, which can cause major health problems. Using autologous stem cells (stem cells obtained from the patient) would eliminate the need for immunosuppressive drugs. The problem is coaxing autologous cells to differentiate into cells that produce insulin.
Researchers from Massachusetts General Hospital have had success using an intestinal hormone called glucagon-like peptide-1 to coax autologous stem cells to differentiate into insulin producing cells. Continuing research is being done on the use of glucagon-like peptide-1.