An islet cell transplant is a medical procedure in which the pancreatic islet cells of a deceased donor are transplanted into a diabetic recipient. People with Type 1 diabetes lack the islet cells in the pancreas that produce insulin and regulate blood glucose levels. Diabetic people must inject insulin several times a day in an effort to prevent high levels of glucose from accumulating in the blood. Replacing pancreatic islet cells by means of an islet cell transplant may help the patient produce insulin naturally and reduce dependence on external insulin.
The pancreas is an oblong-shaped organ that is located just beneath the stomach. It contains clusters of endocrine cells known as the islets of Langerhans. These islet cells secrete the hormone insulin that regulates glucose levels in the blood.
Insulin allows glucose that is ingested to pass from the bloodstream into all cells of the body. These cells can then use the glucose as an energy source to support the function of the organs. Without a steady supply of insulin, glucose would remain in the bloodstream and would not be available to the rest of the body for energy.
Type 1 diabetes is an autoimmune disorder in which the beta islet cells of the pancreas are destroyed. The diabetic patient cannot produce insulin and must inject it several times a day. An islet cell transplant may restore internal insulin production and reduce the need for these injections.
Patients who undergo an islet cell transplant may need to be hospitalized for up to two days. To perform the transplant, a physician first harvests the pancreas of one or more deceased donors. Since the islet cells make up only a small portion of the total pancreas tissue, the donor pancreas needs to be digested with the enzyme collagenase. This enzyme breaks apart the tissue and the islet cells can then be separated from the remaining tissue of the pancreas by centrifugation.
These purified islet cells are then transplanted into the liver of the recipient through a plastic catheter that has been inserted through the abdomen and into the portal vein. The physician slowly transfers the cells into the patient and the cells become lodged in the liver. Once established, the cells should begin secreting insulin in response to changes in blood glucose levels of the recipient.
Since the new islet cells are from an unrelated donor, the immune cells of the recipient may reject the islet cells as foreign. This requires the recipient of an islet cell transplant to take medication to suppress this immune response. Patients may also experience a decrease in function of the new islets after one to two years.
