Borrowed Time: The Science of How and Why We Age

220 Pages·2016·1.76 MB·English

by  Sue Armstrong

Also available in the Bloomsbury Sigma series: P53: The Gene that Cracked
the Cancer Code by Sue Armstrong Spirals in Time by Helen Scales A is for
Arsenic by Kathryn Harkup Breaking the Chains of Gravity by Amy Shira
Teitel Herding Hemingway's Cats by Kat Arney Sorting the Beef from the Bull
by Richard Evershed and Nicola Temple Death on Earth by Jules Howard
The Tyrannosaur Chronicles by David Hone Soccermatics by David Sumpter
Big Data by Timandra Harkness
Goldilocks and the Water Bears by Louisa Preston Science and the City by
Laurie Winkless Bring Back the King by Helen Pilcher Furry Logic by Matin
Durrani and Liz Kalaugher Built on Bones by Brenna Hassett My European
Family by Karin Bojs 4th Rock from the Sun by Nicky Jenner Patient H69 by
Vanessa Potter
Catching Breath by Kathryn Lougheed PIG/PORK by Pía Spry-Marqués
The Planet Factory by Elizabeth Tasker Wonders Beyond Numbers by Johnny
Ball Immune by Catherine Carver
I, Mammal by Liam Drew
Reinventing the Wheel by Bronwen and Francis Percival Making the Monster by
Kathryn Harkup Best Before by Nicola Temple
Catching Stardust by Natalie Starkey Seeds of Science by Mark Lynas
Outnumbered by David Sumpter
Eye of the Shoal by Helen Scales Nodding Off by Alice Gregory
The Science of Sin by Jack Lewis The Edge of Memory by Patrick Nunn Turned
On by Kate Devlin
For my sisters, Jane and Julie, who have shared this whole journey with me so
far; and for Fred, who joined me halfway
We all live most of our lives on borrowed time, time that our stepmother nature
never intended us to have.
Bryan Appleyard

Contents
Preface
Chapter 1: What is ageing?
Chapter 2: Wear and tear?
Chapter 3: Telomeres – measuring the lifetime of cells
Chapter 4: Cell senescence – down but not out
Chapter 5: Old before their time
Chapter 6: Ming the Mollusc and other models
Chapter 7: It's in the genes
Chapter 8: Eat less, live longer?
Chapter 9: The immune system – first responders
Chapter 10: The immune system – the specialists take over
Chapter 11: The bugs fight back
Chapter 12: HIV/AIDS – adding insult to injury
Chapter 13: Epigenetics and chronology – the two faces of time
Chapter 14: Stem cells – back to fundamentals
Chapter 15: Something in the blood?
Chapter 16: The broken brain
Chapter 17: Alzheimer's disease – the family that led the way
Chapter 18: Alzheimer's disease – a challenge to amyloid
Chapter 19: It's the environment, stupid
Chapter 20: Treat the person, not the disease
Chapter 21: Ageing research – from the lab into our lives
Notes on sources
Acknowledgements
Index
Preface
Consider this: the Greenland shark can live for more than 400 years and appears
to remain physically fit and fertile to the end. Or this: there is a type of jellyfish
that swims the Mediterranean and the seas around Japan whose individuals are
able to revert to the larval state and regrow to adulthood countless times. In other
words, it is biologically immortal. So too the hydra, familiar to many of us from
our first biology lessons looking at drops of pond water under a microscope: its
body is composed entirely of immortal stem cells, and a whole new hydra can be
regenerated from any little piece that gets chopped off. These last two creatures
seem to possess the gift of eternal youth and vigour – and never die of old age,
as far as anyone knows for sure.
The question of exactly how and why organisms – most especially us – age has
teased scientists for centuries, yet there is still no agreement. There are a myriad
competing theories, from the built-in obsolescence of the ‘disposable soma’
theory (which basically proposes that Nature doesn't have much use for us once
we've passed our reproductive years and hasn't invested in good enough repair
and maintenance systems to keep us going indefinitely) and the idea that ageing
is wear and tear like the rusting of a car or the weathering of a canvas tent, to the
ticking clock of the shortening telomeres that measure out the lifespan of our
dividing cells, and the idea that ageing and death are genetically programmed
and controlled. A growing number of respected scientists even believe that
ageing is a disease, and it can be treated. Some go so far as to suggest ageing can
be ‘cured’, so that we too could potentially live forever.
I found this last idea – the quest for ‘immortal life’ – so exasperatingly
narcissistic that I contemplated giving up on this book near the start. But since I
had already booked a flight to California (where else?) and made plans to meet a
bunch of scientists when the big doubts struck, I decided to go anyway, enjoy the
trip and make a decision when I had talked to some leading people in ageing