Researchers from Sao Paulo in Brazil have announced that in a group of fifteen insulin-requiring, newly-diagnosed patients with type 1 diabetes, stem cell therapy has preserved beta cell function and eliminated the need for insulin for up to 35 months so far.
The procedure is called autologous nonmyeloablative hematopoietic stem cell transplantation (AHST). First the patients underwent high-dose chemotherapy to eliminate the white blood cells that were attacking the pancreas. The process shut down their immune system and stopped further destruction of the twenty to forty percent of their beta cells that remained. Then they were injected with a chemical that freed their own (autologous) stem cells from their bone marrow, which is full of stem cells. These hematopoietic stem cells (bone marrow cells that are precursors of immune T-cells) were filtered out of their blood, treated, and then re-injected into their blood stream in order to re-start a new and better immune system.
By using this procedure, the researchers apparently reset or retrained the patients immune systems, and the symptoms of diabetes were reversed. The researchers believe that the stem cells developed into new white blood cells that do not attack the pancreatic beta cells.
Fourteen of the patients, who began the trial at varying times, no longer have to use insulin: one has been insulin-free for 35 months, four for twelve months, and seven for six months. Two who started late have been insulin-free for one and five months each. One patient resumed insulin use one year after AHST.
The findings are considered very preliminary, as the study was small, quite short, and did not have a control group. None of the researchers feel comfortable calling the procedure a cure or even a breakthough. There are still numerous questions about how exactly how it works and for how long. It is still not known whether the patients honeymoon period, in which the beta cells still function for a time after diagnosis, played into the results.
JAMA, April 2007