Blood Stem Cell Transplant Leaves Diabetes Patients Insulin Free -- So Far
Daniel J. DeNoon
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Reviewed By Louise Chang, MD
In type 1 diabetes, the body can't make the insulin it needs, and so insulin injections are necessary for treatment. After their transplants, most of the patients in the study became free from insulin injections.
It's the first time the treatment has been used in type 1 diabetes, although it's helped patients with other autoimmune diseases. The early success is encouraging -- but nobody is using the word "cure."
It's not yet clear exactly how the stem cell treatment works, or even whether it truly works at all. And it's far from clear how long treated patients will remain insulin free.
"Very encouraging results were obtained in a small number of patients with early onset disease," conclude researchers Júlio C. Voltarelli, MD, PhD, of the University of São Paulo, Brazil, and colleagues.
The researchers warn that longer follow-up of trial patients, further biological studies, and, finally, a clinical trial will be needed to confirm that the treatment works. Their report appears in the April 11 issue of TheJournal of the American Medical Association.
Early Results, Enormous Promise
In type 1 diabetes, haywire immune cells attack the insulin-making beta cells in the pancreas. This means people with type 1 diabetes can't make the insulin they need and require the use of supplemental insulin. The goal of the treatment is to get rid of these bad immune cells and to replace them with immature cells that have not yet learned bad habits -- thus stopping beta-cell damage and restoring proper immune function.
The treatment is called autologous nonmyeloablative hematopoietic stem cell transplantation. It's a four-step process:
- Soon after diagnosis of type 1 diabetes -- while a person still has plenty of beta cells left -- the patient is given drugs that stimulate production of blood stem cells.
- The blood stem cells are removed from the patient's body and frozen for later use.
- The patient is given drugs and antibodies that kill off immune cells, leaving other blood cells intact.
- The blood stem cells are reinfused into the patient.
The treatment didn't work in the first patient, probably because he had too few beta cells when he started.
But the next 14 carefully selected patients did much better. All were treated soon after diagnosis of type 1 diabetes. All eventually stopped needing insulin -- for one to 35 months.
In an editorial accompanying the study, University of Miami diabetes researcher Jay S. Skyler, MD, warns against "false hope based on the preliminary nature of the study results."
Skyler warns that much work remains to be done:
- The study did not include a control group. This makes it impossible to know what would have happened if similar patients had received no treatment -- an important factor, given that soon after diagnosis, many type 1 diabetes patients enter a "honeymoon" period of remission.
- It's simply too soon to know how well the treatment worked, or whether patients eventually will do better than untreated patients.
- It's not at all clear whether the treatment works because it stops beta cell destruction or whether it allows beta cells to regenerate.
Skyler also notes that this treatment isn't the only cellular treatment now being developed for type 1 diabetes. Other treatments include infusions of regulatory cells to reorient autoimmune cells, umbilical cord cells, embryonic or adult stem cells, and bone marrow transplant.
"As these further studies confirm and build on the results of Voltarelli and colleagues -- the time may indeed be coming for starting to reverse and prevent type 1 diabetes mellitus," Skyler suggests.
SOURCES: Voltarelli, J.C. TheJournal of the American Medical Association, April 11, 2007; vol 297: pp 1568-1576. Skyler, J.S. TheJournal of the American Medical Association, April 11, 2007; vol 297: pp 1599-1600.
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