The dream of using “vampire” techniques to look younger and
live longer might have delighted goths and the vain alike. But scientists have
warned them not to get too excited. They have said that the treatments, which
involve taking young blood and injecting it into older people in an attempt to
rejuvenate people’s bodies, don’t actually work. But the research has found
that old blood does in fact perform an important part of the ageing process and
contributes to declining health. That might mean that there are treatments for
older blood that helps relieve those effects. 

The same team had previously
found that giving older mice younger blood seemed also to give them a new lease
of life. They published their work in a study in 2005. It quickly led to talk
of vampires and hopes that similar techniques could be used to improve the
lives of people, too. But the study wasn’ t able to control the flow of blood
precisely enough to be sure about how the effect was working. For the new
study, precise measurements were made of the way old mice responded to young
blood, and viceversa. It showed that young blood made little or no difference
to indicators of ageing and health in older mice. In contrast, young mice
receiving older blood experienced significant deterioration of their tissues
and organs.

 The rapid changes occurred within 24 hours and affected multiple
tissues including muscle, liver and brain. Lead scientist Irina Conboy, from
the University of California at Berkeley, US, said, “Our study suggests that
young blood by itself will not work as effective medicine. It’s more accurate
to say that there are inhibitors in older blood that we need to target to
reverse ageing.” Mice in the original experiment not only shared blood but also
organs, so that older animals benefited from young lungs, immune systems,
hearts, livers and kidneys. 

The new study, reported in the journal Nature
Communications, removed the influence of shared organs. In a series of trials,
blood was exchanged between an old mouse and a young one until each animal had
half its blood from the other. Various indicators of ageing were then tested
including liver growth, scarring and fattiness, brain cell development
affecting learning and memory, and muscle strength and repair.

 The most telling
results came from the brain tests. Older mice showed no improvement in neural
regeneration from stem cells after receiving young blood but young mice given
old blood saw a more than two-fold drop in brain cell replacement. Conboy
added, “Under no circumstances did young blood improve brain neuro-genesis in
our experiments. Old blood appears to have inhibitors of brain cell health and
growth, which we need to identify and remove if we want to improve memory.”