Issue 121 Item 1 80 Percent of Patients Remain Insulin-Free One Year After Islet

One-year, insulin-free status also was achieved in a child who received a mixture of pig islet cells, without the use of immunosuppressive drugs. An increasing number of patients with diabetes are able to give up insulin following transplantation of islet cells, according to multiple studies presented at the XIX International Congress of The Transplantation Society held in late August. One report of new international data shows 80 percent of patients remain insulin-free one year after receiving infusions of the insulin-producing cells harvested from donor pancreases, a success rate similar to whole pancreas transplantation and markedly better than the 14 percent rate reported for the years 1998-2000.

One-year, insulin-free status also was achieved in a child who received a mixture of pig islet cells, without the use of immunosuppressive drugs and without her immune system attacking the animal cells, reported Dr. Rafael Valdes from the Children’s Hospital of Mexico and colleagues from the University of Western Ontario and Diatranz, Ltd., of New Zealand. A second child was off insulin for 6 months and currently requires 75 percent less insulin than before the transplant.

The mixture of cells consisted of islet cells harvested from pancreases and testicular Sertoli cells taken from neonatal pigs. Sertoli cells are thought to have a special ability to subdue immune system T cells, which normally fight against the presence of anything foreign, including transplanted cells or tissue.

The researchers gave the cell mixture to 12 children with type 1 diabetes and who were between the ages of 11 and 17. No immunosuppressive drugs were administered to protect the cells from being rejected. Six of the 12 patients have functioning grafts, and after receiving additional transplanted islet cells at 20 weeks, have shown improvement in their islet function.

"Whether these results can be duplicated by another center remains to be seen," said Dr. Camillo Ricordi of the Diabetes Research Institute at the University of Miami and co-chair of the congress. "The scientific community at large may be skeptical until more data is available and more patients are studied," he added.

Nonetheless, the findings suggest that it’s possible to obtain insulin-producing cells from sources other than human pancreases, which like other donor organs, are in scarce supply. In addition to the scarcity of donor pancreases, the amount of time that the organs can be safely preserved is limited, and there is a competition for these scare resources between centers performing islet cell transplants and those that transplant the entire organ.

Unlike solid organ transplantation, for every patient needing an islet cell transplant, two donor organs usually are required to provide the number of cells needed for successful transplant. Preliminary results from the University of Minnesota, however, suggest that in certain recipients successful transplants may be achieved with the islet cells from single donors.

With between 120 and 140 million people worldwide suffering from diabetes, much research is focused on making more efficient use of available organs as well as identifying additional sources of viable cells for transplantation.

In a study presented by Dr. Bernat Soria of Miguel Hernandez University in Alicante, Spain, mouse stem cells were successfully coaxed into producing islet cells that normalized blood glucose levels within a week of being transplanted into mice with induced diabetes.

In other studies, researchers from the University of Alberta, who in 1999 announced success transplanting human islet cells using a novel immunosuppressive regimen widely known as the "Edmonton Protocol," reported that 70 percent of their patients are insulin-free at two years and one patient has been off insulin for more than three years. More than 10 centers have seen similar success using variations of the Edmonton Protocol, the Canadian researchers said.

According to the International Islet Transplant Registry, new data indicates 28 of 35 patients (80 percent) who received islet transplants alone (neither with nor following a kidney transplant) were off insulin at one year. Data from earlier years showed that insulin independence was achieved in 11 percent of those who received islets with or following kidney transplants between 1990 and 1997, and in 14 percent of patients transplanted between 1998 and 2000.