Marvelling at stem cells

if you could have any superpower

what would it be would you like to

become invisible

just like that would you like to be able

to fly around and levitate

or maybe you would love the ability to

read someone’s mind

that’s usually the answer i go for now

i’m pretty sure we have all been asked

that question

at some point during our lives right we

all have wished we had

some kind of superpower whatever that

might be

maybe it was something that could help

make our lives easier or better

something that could help us to be one

step ahead of our competition

or something that could help us achieve

our dreams and goals and help make a

difference to the world

now i am a bit of a superhero fan i

love the marvel movies and you can often

find me

lounging on the sofa popcorn in hand

ready to watch them for

the millionth time and every single

time i still find myself wondering how

awesome it would be to have the

superhuman strength

of the incredible hulk to have the speed

stamina and reflexes of the black

panther

or simply the technological genius of

iron man

and then i end up wondering if any of

them would actually

be possible now my favorite superheroes

are deadpool

and wolverine why well because in my

opinion

they have the coolest superpower you

could ever ask for

they have the ability to regenerate

but what if i told you that that ability

of regeneration

was not complete science fiction

meet the planarian this is a type of

flatworm

that has these incredible regenerative

abilities

in fact some species of planarians have

such

astonishing regeneration capabilities

that if you cut it in half at any point

along its body

then the head part would grow a new tail

and the tail part would grow in your

head

in fact if you cut one single worm into

four pieces

you would end up with four completely

whole

new worms how incredible is that

and that’s not the only example this

is an axolotl it’s a type of salamander

and the only vertebrate we know about

that can regrow whole limbs and tails

if you amputated it at the wrist level

it would grow a whole new hand

if you amputated it at the shoulder

level it would grow a whole new arm

it can regrow the front portion of its

brain its testes and if its spinal cord

got crushed

in about three weeks time everything

would have

regenerated and reconnected so that it

could walk again

have i convinced you that this would be

a pretty cool superpower to have yet

now i could marvel about this for hours

on end

but what’s the secret how do axolotls

and planarians

starfish and sea cucumbers deadpool and

wolverine

how do they all regenerate well the

answer to that

is all to do with stem cells

now stem cells are these incredibly

special cells that i became

fascinated by as soon as i learned about

them in school

then my curiosity to understand them and

their potential

just grew and grew throughout university

and ultimately led to me researching

them for four years during my phd

so let me just start to tell you just a

little bit about how

special these cells are now there are

approximately

37.2 trillion cells in your body

37.2 trillion

now for comparison there are only 7.8

billion people on the planet

so that means we would need 4769

identical copies of earth just to have

the same number as

people as there are cells in just

your body now each one of those cells

has their own specialized job to do

but every single one of them came from a

stem cell

an unspecialized cell that with the

right guidance and instructions

can become any cell type you can think

of

stem cells are what we call

undifferentiated cells

they’re kind of like the blank tiles you

use in scrabble

they don’t have a specific job or

function yet unlike

your skin cells for example that protect

pathogens from entering your body

or the rod and cone cells that sit at

the back of your eye

and help us to detect different shapes

and colours

but stem cells do have the potential to

create all of these cells and more

it’s just the number of cell types that

a stem cell can create

depends on its potency

now when parents love each other very

much and they do the unthinkable

they can create a fertilized egg now

this

single cell holds all the potential and

instructions to create a human life it’s

the ultimate stem cell because

not only can it create all the cells

that make up a human body

but it also creates a placenta and an

umbilical cord too they’re called

totipotent stem cells now this one cell

it divides to make two cells those two

cells become four cells

and then eight cells 16 32 and so on and

so on

until you reach around 200 to 300 cells

you’ve now become what is called a

blastocyst

and within this tiny structure is a

small mass of pluripotent stem cells

stem cells with the right guidance and

instructions

can become any cell type that you find

in your body

now stem cells aren’t just present

during development they’re present in

our bodies right now too

you can find them in your bone marrow in

your skin

in your brain in your liver even the

follicles in your hair

the difference with these though is

they’re slightly more limited in the

number of cell types that they can

become let’s take our bone marrow stem

cells for example

they can create any of the cell types

that make up your blood

but they can’t create a brain cell or a

liver cell for example

in fact there are some stem cells in

your body that just create

one specialized cell type

so stem cells aren’t just the molding

putty from which we grow

as a human being but they’re also a key

part of our body’s repair kit

so that we can replace worn out cells

if we go back to our cute little friend

the axolotl

if it lost its tail then those cells at

the injury site would get converted

back into stem cells then with the right

guidance and instructions

those cells can start to form bone cells

and muscle cells and nerve cells and any

other cells you can find in a tail

it can start to heal itself and regrow

that tail

just like it would have done the first

time during development

now unless one of you watching this is

hiding a quite impressive secret

and you won’t be surprised to hear that

us mighty humans

but we’re kind of pathetic at

regeneration the best we can manage is

the very tips of our fingers

and our liver has some ability to

regenerate to full size

if some of it had to be removed during

surgery

so those superpowers of deadpool and

wolverine aren’t going to be happening

for me anytime soon

but what about the future we came from

the ultimate stem cell

there are stem cells in our body and we

have some ability to regenerate

will we ever be able to reach superhero

regeneration status

now because of a stem cell’s ability to

create all of these different types of

cells

as well as crucially being able to make

identical copies of themselves so we

never run out of this precious cargo

there is a whole field of research

dedicated to finding new ways

of harnessing the potential of stem

cells so that we can heal and repair our

bodies

it’s called regenerative medicine

now i’ve told you about adult and

embryonic stem cells already

but there’s another type of stem cell

i’d like to introduce you to

they’re called induced pluripotent stem

cells

and they actually come from your own

skin cells it’s just then that in the

lab they get converted back into

pluripotent stem cells

the kind that can create any cell type

you find in your body

and then just like when you’re lost and

you need to ask for directions

these induced pluripotent stem cells can

be guided and directed

to become any cell type you desired to

help treat

disease induced pluripotent stem cells

have

already been converted into a wide

variety of cell types

such as heart cells that you can see

beating together

in a dish to cartilage cells to brain

cells to

skin cells even retinal cells from your

eye

the idea is that these newly created

tissues

could be transplanted back into a

patient to help repair damaged organs or

replace diseased tissue

and all without the fear of rejection

because those cells well they came from

you originally

there are other areas of research even

looking at

transplanting your own stem cells into

damaged regions

there was one particular study involving

blind patients who had

chemically burnt eyes and they had stem

cells from their healthy eye

transplanted into their damaged eye and

the result

was that after 30 years or so of being

blind

these patients could see again because

the stem cells had repaired

the damage in their eye and the research

avenues

don’t just stop there there are

researchers trying to create whole

organs from stem cells and scaffolds

there are researchers looking at ways to

create blood cells for use in

transfusions

and other researchers trying to look at

ways to treat spinal cord injuries

and so many more now could you imagine

living in a world where no one was

waiting on an organ donor register

there was no shortage of blood donations

for use in operations

and there was real hope for those

suffering from paralysis

all because of stem cells

now this is an image of the stem cells i

study during my phd

and research can get really tough and

frustrating at times

and it can be so easy to lose track and

want to give up

and just throw in the towel but looking

down the microscope at those stem cells

every single day was something i could

never get bored of they were a constant

reminder of what i was helping to work

towards even if it was the tiniest piece

of the puzzle

and the potential that these stem cells

had to help others

it also reminded me of what i could

achieve as a scientist

and the dreams and goals that i could

reach with the right guidance and

instructions

it also reminded me that we all started

off as this one

single stem cell and yet we all end up

as this beautiful concoction

of 37.2 trillion

different cells and then with the right

guidance and instructions

to each of us grow up to harness our own

strengths and superpowers

and grow up to be whatever we want to be

just like those stem cells

and just like us mere humans and every

single one of the cells that make up our

bodies

superheroes come in all different shapes

and sizes

and they all have their unique strengths

and superpowers

and just like us mere humans and every

single one of the cells that make up our

body

each superhero on their own cannot

really

make a difference it’s only when they

come together and

utilize each other’s superpowers and

strengths can they really

make change and the same goes for you

for me and for all of us together

so i want you to go away today and not

think about what superpowers you want

but what superpowers you have because

you do have them

almost definitely more than one i’ve

even told you today about a regenerative

superpower that you probably didn’t even

realize you had

so until that day where we could become

the next deadpool or wolverine

i want to ask you what superpowers do

you have

because it’s not just stem cells that

are a marvel

you are a marvel too thank you