The Guardian | 30.04.22 | SATURDAY | 73I
S T H E R E A N Y WAY TO AVOI D the decay and
frailty that come with age? Jeff B e z o s t h i n k s s o.
A biotech company that the founder of Amazon
has helped fund, Altos Labs, is said to have $3bn
a t i t s d i s p o s a l t o r e s e a r c h w a y s o f h o l d i n g b a c k
the clock. Closer to home, scientists at the
Babraham Institute in Cambridge recently announced
they had altered a 53-year-old woman’s skin cells so
they behaved as though they were 30 years younger.
Promising as this may seem, it’s a long road from the
lab to the clinic. But the diffi culty of translating
scientifi c breakthroughs into treatment hasn’t stopped
an explosion in research. To understand why the once
fantastical idea of preventing or reversing ageing is even
considered a possibility these days, we need to
appreciate exactly what happens as we get older.
The human body is made up of cells in a constant
c y c l e o f l i f e a n d d e a t h. D i ff erent types of cells have their
own inner clocks, determining how long they live.
Sperm cells live about three days , while some brain
cells last a lifetime. The upper layer of skin which you
can see and touch is regenerated every 30 days or so.
As time goes by, however, many types of cell in the
human body become less good at reproducing
themselves by dividing. Skin cells from a newborn baby
can divide 80 or 90 times , but cells from an elderly
person divide about 20 times before they stop. So one
reason we age is that our cells age. But other things are
happening too: we become wrinkly because elderly
skin cells produce less collagen and elastin, and
sebaceous glands produce less oil. Surface bruises
happen more easily because blood vessels become
fragile. Ageing is multi faceted.One thing we do know is that t here isn’t actually a
h a r d b i o l o g i c a l l i m i t t o h o w l o n g w e c a n s u r v i v e. S o m e
animals live much longer than we do. Jonathan , for
example, is a 190-year-old giant tortoise from the
Seychelles. Other tortoises might be even older, but
J o n a t h a n i s r e c o g n i s e d b y t h e G u i n n e s s Wo r l d R e c o r d s
as the oldest living land animal because there’s a photo
of him in his heyday aged 50 , munching on grass.
Bowhead whales can live for more than 200 years and
some sponges are thought to survive for more than
2,000. The oldest human whose age has been verifi ed
w a s J e a n n e C a l m e n t , w h o d i e d i n 19 9 7 a t t h e a g e o f 1 2 2 ,
outliving her grandson.
Although Calment’s grandson wasn’t as lucky as
her, long lifespans like this do tend to run in families.
Twin studies appear to show that the genetic contri-
bution to longevity is around 25%. Astonishingly,
genetic mutations in nematode worms, which
normally live for about three weeks, can increase their
life span by up to 10 times. Needless to say, nothing
like this is possible for humans. Instead, hundreds of
h u m a n g e n e v a r i a n t s a r e l i n k e d t o a g e i n g , e a c h h a v i n g
a small eff ect on their own, but combining in complexways. Deciphering this picture will require the eff orts
of all kinds of scientists, including biologists,
physicians, mathematicians and computer scientists.
This is an area where having a big budget really
does help.
There is a lot we still don’t know about genes and
ageing but, as we’ve seen, it is possible to manipulate
genes to make cells become young again in a lab dish.
In the mid-2000s, Japanese scientist Shinya Yamanaka
showed that the introduction of four genes – the
Yamanaka factors – into adult cells caused them to
revert to stem cells normally found in embryos (and
capable of becoming all the diff erent kinds of cells in
the human body). Today, researchers are seeking ways
to control this process more fi nely , to use Yamanaka
factors to roll back the age of cells, or repair damaged
tissues, without them going all the way back to an
embryo-like state. This appears to be what the team at
t h e B a b r a h a m a c h i e v e d , b y e x p o s i n g a g e d s k i n c e l l s t o
Yamanaka factors for a relatively short period.
Important problems remain, however, because the
very same factors which make cells young again can
a lso ma ke ca ncer more l i kely.T
H E R E A R E OT H E R I DE A S on the table
for combating ageing. We could, for
example, directly clear away old cells
that are causing problems. Cells that
remain alive but have stopped dividing
are deemed “senescent”. These
senescent cells accumulate in the body over a lifetime- especially in the skin, liver, lungs and spleen –
and have both benefi cial and detrimental eff ects.
T h e y a r e b e n e fi cial because they secrete factors which
help repair damaged tissue, but as senescent cells
increase in number, they can disrupt the normal
s t r u c t u r e o f o r g a n s a n d t i s s u e s. M i c e i n w h i c h s e n e s c e n t
cells were cleared away took longer to show
signs of ageing.
Nobody knows the extent to which Altos Labs, or
any other organisation, is going to solve this puzzle.
B u t w h a t i s c l e a r i s t h a t t h e r e w i l l b e s p i n - o ff s from the
eff o r t , s u c h a s n e w w a y s o f a i d i n g t i s s u e r e p a i r, fi ghting
cancer, or boosting immunity. A crucial point here is
that the mission to beat ageing has a vastness to it in
the same way that landing on the moon wasn’t just
about landing on the moon; it is a journey which will
lead to all sorts of new technolog ies, scientific
knowledge and medical outcomes.
The worms provide a note of caution too. Those
long-lived genetic mutants have a much extended
p e r io d of f r a i lt y, wh ic h e mph a si s e s t he i mp or t a nc e of
focus ing on increasing not just lifespan, but healthspan.
Beyond that, ageing isn’t just a personal issue : it is
entwined with social, economic, psychological and
other concerns. Should we, for example, work until our
70s or 80s? How will we ensure equality when the rich
already live longer than the poor? Perhaps the
m o s t p e r t i n e n t q u e s t i o n o f a l l , t o w h i c h e a c h o f u s m u s t
fi nd our own answer: what will be our purpose? What
would make us happy, in those extra years?
Daniel M Davis is a professor of immunology at the
University of Manchester and Imperial College London,
and author of The Secret Body: How the New Science of
the Human Body Is Changing the Way We Live (Vintage ).
THE BIG IDEAFurther reading
Three books for
a deeper diveAgeless
Andrew
Steele
BLOOMSBURY,
£20The 100-
Yea r L i fe
Ly nda
Gratton and
Andrew Scott
BLOOMSBURY,
£10.99This
Mortal Coil
Andrew Doig
BLOOMSBURY,
£25Could we make ageing
a thing of the past?
Recent advances raise the prospect of living
longer – but at what cost, asks Daniel M Davis
Illustration by Elia Barbieri