Islet Cell Transplants - Type 1 Diabetes

Doctors and researchers at the City of Hope have been developing a new procedure that combines islet cell transplantation with a bone marrow transplant (BMT).

In diabetics, the immune system often views islet cells–the cells that produce insulin–as a danger to the body and attacks them. The result is that the diabetic is not left with enough islet cells to produce sufficient insulin.

Islet transplantation is an experimental treatment that has the potential to decrease or even eliminate insulin dependence.

The islet transplant procedure

Islet cells are taken from the pancreas of organ donors (two donor pancreases are required to harvest enough islet cells for the transplant). During a surgical procedure, islet cells are taken from the donor's pancreas and put into the liver–which is more hospitable to the cells than an unhealthy pancreas–of the diabetic patient where they can begin to produce insulin.

As with all transplants, anti-rejection drugs are required after the procedure. After a successful transplant, the average islet transplant patient produces insulin for two to three years according.

Combining islet cell tranplantation with a bone marrow transplant

Whether repeat transplants can be done is yet to be determined but there is ongoing research into this area. A newer procedure that combines islet cell transplantation with a bone marrow transplant might be a better solution in the future. The goal of the bone marrow transplant is to prevent the patient's immune system from attacking islet cells.

This combination of BMT and islet cell transplantation reversed type 1 diabetes in mice with the use of only 10 percent of the amount of islet cells used in a typical islet cell transplant. Also noteworthy is that the islet cells were tranplanted into the pancreas, not the liver, which may mean better long-term results.

As City of Hope doctor Defu Zeng, who led the preclinical trial of this procedure, describes it,

"By requiring fewer islet cells for transplantation, this strategy would reduce the number of donor organs needed, and would make the native pancreas a suitable site for islet grafts. The new regimen appears to be able to overcome all the major obstacles currently facing islet transplantation procedures."