14 | New Scientist | 2 November 2019
COULD something in your blood
be controlling how you age? The
proteins in blood seem to undergo
three waves of changes as we get
older, with the first wave occurring
while we are in our 30s. And using
the proteins, it is possible to
determine a person’s biological
age from a blood sample.
Blood proteins associated with
youth could help us understand
why young blood seems to
rejuvenate older animals, and
could point to treatments for
ageing, say Benoit Lehallier at
Stanford University in California
and his colleagues.
The first hints that something
in blood might have rejuvenating
properties came from studies in
which old and young mice were
stitched together so they shared a
circulatory system. The gruesome
set-up seemed to benefit the older
animals, while the health of the
younger ones deteriorated.
Since then, other studies
have found that blood plasma
transfusions from young animals
seem to improve multiple aspects
of the health of old animals. Blood
from human teenagers has also
been shown to boost the birth
of new brain cells and improves
cognition in old mice.
Encouraged by such findings,
teams are trialling “young blood”
for age-related disorders like
Alzheimer’s, and, for $8000, in an
unproven approach, transfusions
of plasma from young donors can
be bought at a clinic in California.
To find out what happens to
our blood as we age, Lehallier and
his colleagues looked at proteins
in blood plasma samples taken
from more than 4300 people
aged between 18 and 95. The team
measured the levels of almost3000 proteins in each sample and
found that the levels of almost
1400 of these proteins seem to
change significantly as we age.
In particular, there are three waves
of changes – at about ages 34,
60 and 78 (bioRxiv, doi.org/dc7w).
“The most surprising thing
is that there’s this change at
34,” says Colin Selman at the
University of Glasgow, UK.
“For somebody who’s well
over 34, it’s kind of depressing.”It means that significant
biological ageing is already under
way when we are in our 30s, says
João Pedro de Magalhães at the
University of Liverpool, UK. Other
research has found that molecular
changes in the brain associated
with ageing start to show in our
30s, too, he says. “You don’t just
turn into an old man overnight,it’s a gradual process,” he says.
“It makes sense that some of the
changes associated with ageing
occur at an early age.”
Lorna Harries at the University
of Exeter, UK, thinks the protein
changes might reflect subtle
differences in the body’s external
and internal environments rather
than some dramatic ageing
process. Plenty of people have
children in their 30s, for instance.
“Your physiology undergoes
some major remodelling during
pregnancy and lactation, and that
might well be part of it,” she says.
Lehallier and his colleagues
have used their findings to
develop a “proteomic clock” that
can guess a person’s biological
age based on 373 of the proteins
found in their blood. The clock’s
estimate, which applies to both
men and women, strongly
correlated with the volunteers’
chronological age.
It was also able to guess
biological age. People who were
given predicted ages below theirchronological age performed
better on physical and cognitive
tests, hinting they are biologically
younger than their years.
“It’s a potentially revolutionary
study,” says Selman. The aim of
much of ageing research is to find
a way to increase the proportion
of a person’s life that is spent in
good health, rather than merely
increase lifespan, he says. “They’ve
shown that this proteomic clock
appears to be a good predictor of
late life health, and that’s exciting.”
The clock could be used in
clinical trials to test if anti-ageing
treatments are working, and
to identify people at risk of
premature ageing, says Selman.
Lehallier’s team thinks it is
possible to identify the specific
proteins in blood that might be
responsible for its rejuvenating
effects. “Identifying proteins
within plasma that promote or
antagonise ageing at different
stages of life could lead to more
targeted therapeutics, as well
as preventative therapies,” the
team writes.
We might find some of these
proteins in blood taken from
the oldest participants. People in
their 80s and 90s are likely to have
some kind of protective factor that
has kept them alive, says Harries.
It is also possible that the
important proteins might be
different in men and women.
When Lehallier and his colleagues
compared the protein profiles
of male and female volunteers,
they found differences between
two-thirds of the proteins that
changed with age.
“Really identifying what
particular proteins are important
is going to take a long time, but
it’s exciting research,” says Selman.
“The big drive in ageing research
is to find realistic interventions
to extend lifespan... and this may
be a valid route.” ❚News
AgeingBONKERSABOUTCHINA/ALAMY STOCK PHOTOYour blood reveals your age
Proteins in our blood change as we get older and
could guide anti-ageing treatments, finds Jessica HamzelouIf you feel younger than your
years, your blood may contain
a youthful mix of proteins34
How old you are when age-related
changes arise in your blood