Nov 27 2007
Stem cell scientists are developing a novel approach to slow or possibly prevent the cognitive decline that typically occurs with advancing age.
Adult brains contain highly “regenerative” stem cells, which give rise to new nerve cells everyday. Previous studies have shown that the number of stem/progenitor cells and their progeny declines dramatically with age. Dr Rietze and his team believe boosting the number of stem cells in young- and middle-aged animals will preserve the number of stem cells we have in old age.
The Rietze team are using two separate approaches to increase the number of stem cells typically found in the brain. The first approach is via the acute infusion of growth hormone directly into the brain, which stimulates resident stem cells to divide and increase their number. These latest results suggest growth hormone may play an integral role in regulating brain stem cells and may represent a new target for stem cell-related treatments.
“The idea here is to increase the number of stem cells in young and middle-aged mice,” Dr Rietze said.
“The greater the complement of stem cells, the greater capacity we have to maintain and regenerate the brain as we age.”
The second approach is focused on restoring the number of stem cells in aged mice. This work is based on published studies demonstrating that physical exercise and exposure to an enriched environment can increase the number of new nerve cells in the hippocampus (part of the brain important for learning and memory) in both young and aged mice, and has also been shown to slow or even prevent age-related memory loss.
“We have found that physical exercise in aged mice is as effective as growth hormone in young mice, in increasing resident stem cell numbers”.
“This is an exciting breakthrough which is consistent other published data showing that a physically and intellectually ‘active’ life may prevent or delay age-related conditions and neurodegenerative disorders such as Alzheimer’s disease,” Dr Rietze said.
Dr Rietze presented his research at the annual Pfizer Australia Fellowship awards evening at the Sheraton on the Park in Sydney this week following the announcement of the 2008 Fellowship winners.
His project has been largely funded by Pfizer Australia’s $1 Million Fellowship grant.
The Fellowships are offered to Australian medical researchers and clinicians who can convince an independent panel of scientific and medical experts of their exceptional capability in scientific discovery. The successful applicant receives a five-year grant that provides a salary and also supports all aspects of the proposed research project.
Dr Dan Grant from Pfizer Australia’s medical department said: “Our ongoing commitment to advancing Australian medical research lies behind these bright innovative scientists who we believe can make significant contributions to Australian research and in the long run, may provide the answer to many worldwide diseases.”