UW-Madison researchers discovered a way to promote the growth of neural stem cells, in research that may ultimately benefit patients of Alzheimer's and Parkinson's disease.
Clive Svendsen, the study's senior author, is a UW-Madison professor of anatomy and neurology. The results were published last week in the online journal of the Proceedings of the National Academy of Sciences.
Svendsen's team was researching stem cells, which are cells that can ultimately differentiate into more specialized cells, when a colleague suggested that his own research might tie in with Svendsen's.
Henry Lardy, UW-Madison professor emeritus of biochemistry, had been working with several compounds that enhanced memory in aging mice. Lardy provided Svendsen's team with 10 of the compounds, speculating that the molecules might also enhance stem cell growth. One compound was dehydroepiandrosterone, a naturally occurring steroid hormone in the body.
\We assumed DHEA would simply be an inactive control,"" said Lardy.
But the team's experiments indicated that DHEA was a primary factor in stimulating the growth of neurons.
One member of the team was Dr. Masatoshi Suzuki, visiting professor from Tokyo University. Suzuki said when they first cultured stem cells in a lab dish, 10 percent would become neural stem cells.
""But when we added growth factors including DHEA, 29 percent of the cells became neural stem cells,"" Suzuki said.
The incremental 19 percent would otherwise have remained undifferentiated, or unspecialized, he added.
Being able to promote the growth of neural stem cells may ultimately allow researchers to examine in greater detail what happens to brain cells and memory as we age.
DHEA, or dehydroepiandrosterone, is related to estrogen and testosterone. The mechanism by which it functions is still unknown, writes Svendsen.
""What we are hoping is that maybe the stem cells convert DHEA to something we have never seen before,"" said Lardy.
This might allow researchers to develop treatments for brain disorders, or to promote memory retention in older people.
""Someday it will be possible to implant stem cells into the brain of Alzheimer or Parkinson patients,"" Lardy said.
Suzuki said the next step is to test DHEA in rats before applying these results to human subjects.
DHEA is commercially available, and is touted on some Web sites as a supplement that increases lean body mass, decreases ""bad"" cholesterol and prevents cancer.
While early research tentatively supports these claims, Suzuki warned that the side effects are not fully understood.
""Any steroid in high concentration is dangerous in humans,"" he cautioned.
Lynda S. Wright and Padma Marwah, both UW-Madison senior scientists, contributed to Svendsen's research.
