“The Chicago Diabetes Project’s goal remains to provide a functional cure for all people with diabetes who seek treatment.”
José Oberholzer, MD, Director, The Chicago Diabetes Project
Insulin producing cells for transplant are obtained from a donated pancreas. Surgeons and scientists work as a team in the Chicago Diabetes Project’s state-of-the-art laboratory to separate the insulin producing cells from the remainder of the pancreas. This step is called "digestion” and it is carried out using a Ricordi chamber, a device named for the inventor, Dr. Camilo Ricordi. Once freed from the tissue of the pancreas, the islets (clusters of insulin producing cells) are isolated from the other tissue with the use of density gradients and centrifuge. The islets are lighter than other pancreas tissue and, by spinning in this gradient, the islets can be isolated into a separate layer where they can be retrieved.
The actual transplantation procedure takes approximately one hour. A transplant begins with the patient awake but drowsy, in the Radiology Department. The area on the abdomen where the tiny catheter will be inserted for the infusion of the islets is numbed by a local anesthetic. A small incision is then made in the abdomen.
Using ultrasound technology to guide them, physicians specially trained in this procedure place a catheter through the patient’s upper abdomen and into the main portal vein, or blood vessel, in the liver.
Then, using the catheter, the transplant surgeon injects the islet cells into the portal vein of the liver. The transplanted islet cells lodge in blood vessels in the liver and begin producing and releasing insulin almost immediately. Patients generally leave the hospital in less than 24 hours after the transplant and are ready to resume their normal activities within a few days.
Much like any transplant procedure today, patients take prescribed immunosuppressant drugs without steroids to prevent their immune system from attacking the transplanted islets. The blood glucose levels improve dramatically in successful cases, with patients often achieving complete insulin-independence and normal glucose tolerance.
Depending on a number of factors, including the size of the patient, it can take two or three additional transplants before a patient can stop injecting insulin entirely.
It is the ultimate goal of the Chicago Diabetes Project to transplant donated human islet cells enclosed in biocompatible capsules (made from alginate, a product derived from seaweed.) These capsules have tiny holes small enough to block immune cells from getting in and destroying the islets, but large enough to allow nutrients and insulin to pass through. When transplanted, the capsules prevent rejection and recurrence of diabetes, and may eliminate the need for chronic, systemic immunosuppressive drugs.
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