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