A controversial stem cell treatment tested in Brazil has freed patients with type-1 diabetes from dependence on insulin. Since the treatment some patients have been able to stop from injecting the drug for years.

“It’s the first time treatment has made patients insulin-free, although I never say it’s a cure,” says the co-leader of the team, Richard Burt of Northwestern University Feinberg School of Medicine in Chicago, Illinois.

“Some patients relapsed and had to go back to using insulin, but even if they did, they didn’t require as much as they did before the treatment.”

The treatment is designed to stop the immune systems of patients with type-1 diabetes from mistakenly destroying the pancreatic islet cells which manufacture insulin, the hormone that keeps blood sugar levels in check.


Spectacular preliminary results from the trial in 2007 were dismissed by some critics who claimed the outcomes may have been down to immunosuppressive drugs used in the treatment regime, or simply due to better care of the patients because they were in a clinical trial.

Islet recovery

But the latest results, which include updates on the original 15 patients and data from a further eight, suggest the treatment may indeed work as proposed. Demonstrating that most patients had elevated blood concentrations of C-peptide, a breakdown product of insulin production, Burt says is a clear sign that the patients were making insulin themselves.

“The remaining islets are not being attacked, and there’s evidence of a recovery in the islet cells [which produce insulin],” says Burt. In some patients, the levels of C-peptide trebled, reaching a peak about two to three years after treatment compared with beforehand.

Developed mainly by Burt’s colleague Júlio Voltarelli of the Regional Blood Center in Ribeirão Preto, Brazil, the treatment relies on extracting and storing CD34 stem cells from the blood of patients. These stem cells can grow into all white blood cells of the immune system.

In the next step, patients receive drugs that destroy what remains of their immune systems, obliterating at the same time the components of the immune system that attack the islets.

Finally, the saved stems are returned to the patient so that they can regenerate afresh an immune system that will no longer attack islet cells.

Insulin sufficiency

The latest results appear to show that in the 20 patients benefiting from the treatment, their blood contained elevated levels of C-peptide, proving that the patients were making insulin themselves.

Twelve of the 20 remain insulin-free, one for five years, four for three years, three for two years and another for one year. Levels of C-peptide typically peaked about 2 years after treatment, trebling in concentration compared to beforehand. “The remaining islets are not being attacked,” says Burt.

Even the eight who relapsed have been on lower doses of insulin than beforehand, and still have higher levels of C-peptide, suggesting that their islet cells have benefitted from the treatment. Two became insulin-independent again after receiving the sugar-lowering drug, sitagliptin.

But the treatment didn’t work in three patients, and nine men later suffered from low sperm counts. Another two suffered from pneumonia. None of the patients died.

Follow-up trial

Burt says that a larger trial is now planned to take place both in Brazil and in the US. This time, it will randomised so that some of the patients receive placebo.

As with the existing trial, newly-diagnosed patients will be selected. They still have most of their islet cells, and so stand to benefit more than patients whose islet cells have been destroyed.

Burt also said that the treatment is unlikely to benefit type-2 diabetics as they still make insulin anyway. Their diabetes results because the rest of the cells in their body stop responding to insulin as they should.

But a similar procedure developed by Burt has already shown some success in another autoimmune disease, multiple sclerosis. Results published in January showed that many patients benefitted, again, through reprogramming of their immune systems, this time to stop it from attacking nerve and brain cells.

Other researchers remain unconvinced. “It would be wrong to unnecessarily raise the hopes of people living with diabetes about a new treatment for the condition on the back of the evidence provided in this study,” says Iain Frame, director of research at the health charity, Diabetes UK.

Frame welcomed the plans to include a control group in the next, expanded phase of the programme, and urged further research by the investigators to be sure that the treatment itself is causing the improvements.

Journal reference: Journal of the American Medical Association, vol 301, p1573