Stem cells help improve insulin production in diabetes patients

A pioneering stem cell transplant has enabled patients with Type One diabetes to go without insulin injections for up to four years.

Researchers from Northwestern University in the US and the Regional Blood Centre in Brazil treated a total of 23 patients and found that the majority achieved good glycemic control: 20 became insulin injection free for an average of 31 months. Eight had to return to insulin injections but at lower levels and three patients didn't benefit from the treatment. The results were published in the Journal of the American Medical Association (JAMA).

Type1 diabetes usually develops in childhood, and happens when the immune system mistakenly attacks the insulin producing beta cells in the pancreas. The treatment is designed to prevent this from happening. The researchers took stem cells from the bone marrow of each patient and then gave the patients chemotherapy, effectively destroying the immune cells that attack islet cells. They then returned the stem cells to the patients by intravenous injection.

To assess the effectiveness of the treatment the team's analysed the levels of C peptides, which is a by-product of insulin production, in the blood of the patients. All of those who benefited had increased concentrations of C peptides.

In 2007, Julio Voltarelli of the Regional Blood Centre announced early trials of this treatment. His team found that some of their patients were able to live without injections of insulin for months. At the time there was uncertainty whether the changes were as a result of the treatment or the associated medical care. This new work now brings the total number of patients to 23, and some have been followed up for nearly five years.

Dr Iain Frame, director of research at Diabetes UK, said that the researchers need to look at the causes of the apparent improvement in insulin production. He said: 'It is crucial to find out whether this is associated with the timing of the treatment or possible side effects of it rather than the stem cell transplant itself.'

Dr Richard Burt of Northwestern warned that this is not yet a cure and the procedure may only work on those very recently diagnosed. He said: 'We don't believe stem cells form islet cells, but if the islet cells are still there, there might be regeneration if we stop the attack soon enough.'