Stem cells are the origins of all the things
that bring us to life – our organs, bones,
skin, hair and other features. They may also
hold clues to ageing.
Zhou Zhongjun,Associate Professor of Biochemistry, has shown that stem cell numbers decline rapidly in mice with progeria, an accelerated ageing disease, unlike normal mice. Moreover, he identified oxidative stress as the cause for this and used that knowledge to extend the life spans of the mutant mice by rescuing their stem cells.
"We can't say for sure that stem cells are the reason for ageing, but they definitely have an important role to play in the process because when you rescue stem cells, you can rescue or extend the life span of the animals," he says.
Mutant and normal mice have almost the same number of stem
Zhou Zhongjun,Associate Professor of Biochemistry, has shown that stem cell numbers decline rapidly in mice with progeria, an accelerated ageing disease, unlike normal mice. Moreover, he identified oxidative stress as the cause for this and used that knowledge to extend the life spans of the mutant mice by rescuing their stem cells.
"We can't say for sure that stem cells are the reason for ageing, but they definitely have an important role to play in the process because when you rescue stem cells, you can rescue or extend the life span of the animals," he says.
Mutant and normal mice have almost the same number of stem
cells at birth but
this quickly declines in the mutant mice
after a few weeks. Dr Zhou and his team
found that left untreated, half of the mutant
mice they tested died within 20 weeks.
However, those treated with anti-oxidants
such as resveratrol – a constituent of red
wine, among other things – lived to 28 or 29
weeks. In addition, the bone density of the
treated mice was much greater so they had
less osteoporosis, which is related to ageing.
The best results occurred when the mice were treated at one to two months old, but improvements were also achieved in older mice.
Unfortunately, that result does not yet extend to somatic cells – the cells that have differentiated from stem cells into organs, tissues and other body parts. It may also be difficult to test the results in humans.
"Our results give an impression of the relationship between stem cell decline and ageing. So far there is little evidence to show a direct link because technically this is difficult to achieve unless you could physically eliminate stem cells after building up tissues," Dr Zhou says.
"One could imagine, though, that because stem cells are an important resource for replenishment of all these somatic cells in our tissues, that there is some correlation between stem cells and ageing. Whether it's a consequence or cause of ageing is hard to say.
"This area of study could have practical applications in future to improve the health standards of ageing populations and find ways for them to live longer and healthier. If we could improve osteoporosis under normal circumstances, it would mean people suffer few fractures. So the results from the animal experiments should hopefully apply to human situations in future."
The best results occurred when the mice were treated at one to two months old, but improvements were also achieved in older mice.
Unfortunately, that result does not yet extend to somatic cells – the cells that have differentiated from stem cells into organs, tissues and other body parts. It may also be difficult to test the results in humans.
"Our results give an impression of the relationship between stem cell decline and ageing. So far there is little evidence to show a direct link because technically this is difficult to achieve unless you could physically eliminate stem cells after building up tissues," Dr Zhou says.
"One could imagine, though, that because stem cells are an important resource for replenishment of all these somatic cells in our tissues, that there is some correlation between stem cells and ageing. Whether it's a consequence or cause of ageing is hard to say.
"This area of study could have practical applications in future to improve the health standards of ageing populations and find ways for them to live longer and healthier. If we could improve osteoporosis under normal circumstances, it would mean people suffer few fractures. So the results from the animal experiments should hopefully apply to human situations in future."