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.