Lab-grown neurons might repair Alzheimer's brains

Alzheimer's disease kills brain cells that are vital for memory – but now we can make new ones from human embryonic stem cells in the lab. The breakthrough opens the way for testing new anti-Alzheimer's drugs, and raises the hope that one day people with Alzheimer's could receive transplants of lab-grown neurons into their brains to improve their memory.

A type of brain cell called basal forebrain cholinergic neurons is among those that Alzheimer's hits hardest. They die off early in the progress of the disease, a loss which devastates memory and our ability to fully understand our environment. Christopher Bissonnette and colleagues at Northwestern University in Evanston, Illinois, took the first step in growing new ones by studying the genetics of these neurons.

Once the team had deciphered the genetic signals that guide the development of these cells, they were able to coerce human embryonic stem cells into developing in the same way. To initiate the metamorphosis, they created pores in the walls of the stem cell nuclei and slipped in segments of DNA and gene-regulating proteins called transcription factors that are associated with the neurons.

When the researchers transplanted the neurons they had engineered into slices of mouse brain, the cells wove themselves into the tissue of the hippocampus, a brain region involved in the formation of memories. They then began producing the neurotransmitter acetylcholine, which is necessary for memory retrieval.

The new technique is most exciting because it could lead to new kinds of therapy for Alzheimer's, says team member John Kessler. "Now we can have human neurons in a dish in front of us and rapidly screen tens of thousands of drugs," Kessler says.

Lab-grown neurons might repair Alzheimer's brains - health - 04 March 2011 - New Scientist