The cure for diabetes could be sitting in our brains, Japanese researchers say. The AIST Institute in Tsukuba has discovered that using patients' neural stem cells can overcome shortage of insulin-producing cells without the need for gene transfer to treat diabetes. Beta cells in the pancreas produce insulin, which regulates glucose levels. The research has revealed how harvesting stem cells could overcome a lack of beta cell transplants from donors. Diabetes is caused by a lack of insulin production by the pancreas and affects more than 200 million people worldwide. There is currently no cure, leaving patients to rely on external supplies of insulin or treatments to alter levels of blood glucose. The research, led by Dr Tomoko Kuwabara, focussed on developing methods for defining human stem cell differentiation, the process through which cells can be adapted to a specialized role, for use in cell replacement treatments. "As diabetes is caused by the lack of a single type of cell the condition is an ideal target for cell replacement treatments," said Kuwabara. "However donation shortages of pancreatic beta cells are a major hurdle to advancing this treatment. So a safe and easy way of using stem cells for obtaining new beta cells has been long awaited," he added. The hippocampus and olfactory bulb, at the front of the brain provide an easily accessible tissue source for cells that could be transplanted directly into the pancreas. Normally neuronal cells do not produce high levels of insulin, pancreatic cells do. However, once they had been transplanted into diabetic rats the cells not only started to express several key characteristics of pancreatic beta cells, but insulin production was increased and blood glucose levels were reduced. The removal of the transplant increased levels of blood glucose, revealing that transplanting neural stem cells into the pancreas could be an effective treatment for diabetes.