Scientists
have found a biological command center for the ageing process in a lump of
brain the size of a nut. The US team identified the mechanism in the
hypothalamus, which sits deep inside the brain, and showed they could tweak it
to shorten or lengthen the lives of animals.
In a series of experiments, the
researchers found they could extend the lives of mice by a fifth, without the
animals suffering from muscle weakness, bone loss, or memory problems common in
old age. They found that a chemical called NF-kB became more active in the
hypothalamus of mice as they got older. When the researchers blocked the
substance, mice lived up to 1,100 days, compared with 600 to 1000 days for
normal healthy mice. When they boosted NF-kB in mice, they all died within 900
days.
Tests on the animals six months into the study found that those without
NF-kB had more muscle and bone, were better at learning, and had healthier skin
than controls. Further work showed that NF-kB lowered levels of a hormone
called GnRH, which is better known for the central role it plays in fertility
and the development of sperm and eggs. When the scientists gave old mice daily
jabs of GnRH, they found this too extended the animals' lives, and even caused
fresh neurons to grow in their brains.
There may be several ways to slow down
ageing, with drugs that dampen the activity of NF-kB in the brain, or raise
levels of GnRH.
Sourse: Nature
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