Diabetic rats cured with their own stem cells

A cure for diabetes could be sitting in our brains. Neural stem cells, extracted from rats via the nose, have been turned into pancreatic cells that can manufacture insulin to treat diabetes.

Beta cells in the pancreas produce insulin, which regulates glucose levels. People with diabetes either have type 1, in which native beta cells are destroyed by the immune system, or type 2, in which beta cells cannot produce enough insulin.

To replace lost or malfunctioning beta cells, Tomoko Kuwabara of the National Institute of Advanced Industrial Science and Technology in Tsukuba Science City, Japan, and colleagues turned to neural stem cells in the brain.
First, they extracted a tiny amount of tissue from the rats' olfactory bulb, the part of the brain which deals with smell, or from the hippocampus, involved in memory. Each area is accessible through the nose, both in rats and humans.

Next, the team extracted neural stem cells from the tissue and exposed them to Wnt3a – a human protein that switches on insulin production – and to an antibody that blocks a natural inhibitor of insulin production.

After multiplying the stem cells for two weeks, they placed them on thin sheets of collagen which act as a removable scaffold. This allowed the team to lay the sheets incorporating the cells on top of the rats' pancreas without harming the organ itself.

Within a week, concentrations of insulin in the blood of both type 1 and type 2 rats that had received treatment matched those in non-diabetic rats. Elevated blood glucose concentrations also returned to normal.

The cells successfully tackled diabetes for 19 weeks until researchers halted the treatment by removing the sheets of cells, after which the rats' diabetes returned.