Growing new brain cells

Researchers in America have identified a chemical that encourages the growth of new neurons - and protects against neurodegeneration.

Steven McKnight at UT Southwestern and colleagues screened 1000 different chemicals - and found 8 candidates that seemed to support formation of neurons in a region of the mouse brain called the dentate gyrus.  This region, in both mice and humans, is thought to contribute to the formation of new memories, and is one of the few regions known to have high levels of neurogenesis even in adults.

One of the eight candidates, P7C3 had favourable pharmacological properties, so the researchers focussed their attentions on this.  It works by preventing apoptosis - or programmed cell death - in newborn neurons.  The process of neurogenesis is long and perilous - neurons form and migrate over the course of two to four weeks to the desired site, and many do not survive this process.

Further research in mutant mice that lack a gene essential to normal brain development showed a marked increase in neurogenesis when on a prolonged course of P7C3.  As well as new neurons forming, a measurement of electrophysiological activity showed that the dentate gyrus was functioning as it should be - so the new neurons are properly incorporated and functional.

There was also tantalizing evidence that P7C3 also enhanced the birth of new neurons in aged rats.  As rats age, they tend to show a reduction in neurogenesis alongside a reduction in the ability to form new memories.  Rats on a daily dose of P7C3 showed an increased ability in standard learning and memory tests, and also a higher rate of neurogenesis.

The next step is to identify the molecular target for P7C3, but this finding could point the way to new neuroprotective drugs that prevent or treat diseases like Alzheimer's.