Scientists find lifespan control
American scientists have homed in on the part of the brain that controls ageing, managing to keep mice alive and active for up to 100 days past their normal lifespan.
The scientists, at the Albert Einstein College of Medicine in New York, were able to both lengthen and shorten the lifespan of mice, and found that the physical and cognitive abilities of the mice who lived longer also stayed intact for longer.
Medical professor Dongsheng Cai, of the college's department of molecular pharmacology, said the hypothalamus, an almond-sized area of the brain which controls the ageing process, acted as a "puppet master" over a number of other functions.
It controlled our automatic responses to the world around us, our hormone levels, sleep-wake cycles, immunity and reproduction.
But he said the breakthrough in manipulating the biological clocks of mice could have major implications in the staving off of age-related diseases.
The study discovered ageing mice produced increasing levels of nuclear factor kB (NF-kB), a protein complex that plays a major role in regulating immune responses. They found the protein was barely active in the hypothalamus of 3- to 4-month-old mice but became very active in old mice, aged 22-24 months.
Working with three groups of middle-aged mice, scientists gave one group gene therapy that inhibited the protein, the second had gene therapy to activate it, and the third was left to age naturally.
This last group lived, as expected, between 600 and 1000 days. Mice with activated NF-kB all died within 900 days, while the animals with NF-kB inhibition lived for up to 1100 days.
The mice that lived the longest not only increased their lifespan but also remained mentally and physically fit for longer.
In cognitive and physical ability tests after the therapy, the mice that lived the longest outperformed the control group, and the short-lived mice performed the worst.
But Cai said the study had not uncovered the secret to eternal youth.
He said it was unlikely to prolong life indefinitely, because there were many other factors involved.
The study was published yesterday in international science journal Nature.
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