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Among diabetes sufferers, those with the type 1 version of the metabolic condition are decidedly in the minority. In the UK, they number 400,000 – just a 10th of those with the more common type 2.
But if those with the condition are concerned that effort and resources flow more easily to their type 2 counterparts, recent events in the field would suggest otherwise. Some of the most exciting advances in diabetes research are being made by scientists dedicated to understanding and influencing the factors that control type 1.
The condition occurs when the cells in the pancreas that secrete insulin, known as beta cells, are attacked and destroyed by the body’s immune system. The sufferer’s ability to produce insulin – the hormone that regulates blood sugar levels – is rapidly compromised and eventually eliminated.
A cure has so far remained out of reach, but recent strides have brought the prospect considerably closer. Last month, a group of researchers at Harvard University published a paper showing they had created insulin-producing beta cells in the laboratory – and for the first time in the massive numbers needed to allow cells to be transferred into patients.
A team led by Douglas Melton, a Harvard professor whose two children have type 1 diabetes, was able to grow 300m cells at a time in a 500ml flask, only one or two of which would be required to treat a patient. Derived from stem cells, the beta cells were placed into diabetic mice, and continued to produce insulin months after transplantation.
A serious complication for all techniques in which new beta cells are inserted into diabetic patients is not only to keep the cells alive and functioning but to stop the body’s immune system from obliterating them all over again.
Even where patients with transplanted beta cells have had their immune systems shut down by powerful drugs, aggressive lymphocytes – the body’s defence force – have succeeded in destroying the new cells after weeks or months.
Research led by Mark Peakman, a professor of clinical immunology at King’s College London and Guy’s & St Thomas’ Biomedical Research Centre, has brought promising advances. His team showed that certain immune cells appeared to protect the beta cells against attack from their more aggressive brethren. These cells were present in people who had a slow progression of the disease or siblings of diabetes sufferers who never developed the condition – a potential indicator of their importance for resisting type 1.
The number of cells researchers were able to grow in a 500ml flask
After creating quantities of the peptides or proteins that stimulate the protective cells, Prof Peakman administered them to subjects and found they had the ability to modify the immune response in a potentially protective way.
He said the effect was akin to that of a vaccine. “What a vaccine does is reproduce an encounter with something in the immune system in a safe way. What we’re doing is giving a peptide and hoping the immune response to that is beneficial for people at risk.”
The treatment is not for those in whom the disease has fully progressed, since their beta cells cannot be revived. However, for groups at risk of getting it, or those who can be caught at the moment of diagnosis, when the beta cells retain some of their insulin producing abilities, it could prevent the condition from taking hold and allow the body to restore function. And for future treatments that rely on transplantation of cultured beta cells, it could help patients receive the cells without requiring immunosuppressant drugs.
The number of people in the UK with type 1 diabetes
With a second generation of the vaccine ready for safety testing in type 1 patients, Prof Peakman is planning further trials over the next two to three years.
Another therapy which is making waves is one that takes two drugs – neither of which had been successful alone in preserving beta cell function – and combines them to powerful effect.
Researchers led by Michael Haller, a paediatric endocrinologist at the University of Florida, gave low doses of antithymocyte globulin (ATG) and granulocyte colony stimulating factor (GCSF) to 17 patients who had some beta cell function remaining, and found their insulin-producing capability had not declined up to 12 months after treatment.
“Quite remarkably and unexpectedly, patients with established T1D may benefit from such combination immunotherapy,” the researchers said.