The Wonderful World of Blood with Michael Mosley

Of all the wonders of the human body there's one that I think is

more mysterious than any other.

The very sight makes some people faint.

Losing half will kill you.

And it permeates our culture as surely as our bodies.

Blood, it is said, is thicker than water, but what do we really know

about this sticky red substance and its mysterious, life-giving force?

For centuries, it's inspired our darkest flights of imagination,

with the promise that it will help us cheat death, recover our youth.

But now science is finding new ways to tap its true potential.

'I'm going to investigate

'the strange and wonderful world of my own blood.'

Keep going, keep going, that's it.

'I'll learn how to boost its power...

'in the blink of an eye.'

That is cold!

'Find out how it tastes.'

So, here we go, black pudding a la Michael.

'And chart its many highways and byways.'

That is my circulation.

The product of hours spent in the MRI machine.

'Most surprising of all,

'I'll discover why Dracula had the right idea.'

I want to find ways I can meddle with my own blood

and make myself fitter, younger, healthier.

I want to show you what blood can really do.

I'm not fazed by blood, which is just as well

because in this programme I'm going to spilling lots of it.

It's quite strange and slightly disturbing watching blood

flow out of my body, and that's

because blood is such a precious fluid, in fact almost every great

religion and society has imbued blood with almost magical qualities.

I'm making a small withdrawal from my own personal blood bank.

Around half a litre.

Enough to get me through a unique set of trials.

Trials that I hope will reveal five astonishing properties of blood.

And I'm starting with one that is fundamental to life itself.

I live and work in London, which is a sprawling city,

so I like to cycle around, it beats the traffic, it's cheap,

and it's also good for my heart and lungs.

Now, I do this mainly in the hope it will keep me fit,

which these days is something of a uphill struggle.

The harder I peddle,

the deeper I breathe, drawing oxygen into my lungs.

But London traffic aside, there's a limit.

If I really push myself, my muscles start to ache

and the reason for that is hidden deep in my blood.

So what I've got here is two test tubes full of dark, red, rich blood,

and have a look at what happens to this one

when I put some oxygen through it.

It's nice and messy and murky.

As I bubble oxygen through the blood, something happens.

So what you should be able to see now is a colour change,

the one over here is a sort of lighter, brighter, arterial red.

And this is a clue to a transformation taking place

inside us.

In our red blood cells.

We have staggering numbers of them.

Your blood contains around 20 trillion,

and you make 17 million new ones every second.

Each time we breathe in, they extract oxygen from the air,

changing colour as they do so.

And, more importantly, providing life-giving energy.

But there are limits.

Now, blood can only hold

so much oxygen, which is why the colour isn't changing any further.

No matter how much more oxygen I pump in,

once each cell is saturated, that's it, my blood can't take

any more, and this limits what my body is capable of.

But what if I could change my blood so it carries more oxygen?

Would that help me cheat my way to greater fitness?

HE EXHALES

'To find out, I've come to

'the Institute of Sport, Exercise and Health.'

Great effort.

-HE COUGHS

-Lovely!

'We're going to measure the maximum rate at which my blood can

'pass oxygen to my muscles.'

-How does that feel?

-OK.

'It's called my VO2 max.'

So, you're all set.

That's it.

Three minutes of this. That's it, keep going.

That's excellent.

Well done, well done.

'Soon my lungs are burning and my heart is pounding

'as I struggle to keep the oxygen flowing.'

That's it, the muscles are working really hard now,

your heart rate will have increased so the amount of blood being

pumped around your body per minute is increasing.

I can see your breathing has increased,

all of this to just keep

that supply of oxygen to the muscles

until the point where you can no longer go on.

That's excellent. 20 more seconds, come on. That's great.

Really push it. Keep those legs going round, keep going, keep going.

That's it. Stop the load.

That's it, that's it, that's it.

Whoo!

Yeah. I think the thing that surprised me most

was the pain was all in my thigh,

that was what was really hurting, it wasn't my lungs at all.

So it's your legs that stopped you, then, yeah, and that's what's common

with most people, it's the failure of delivery of oxygen to the muscles

which stops you from cycling any more

rather than running out of breath.

So the problem was muscles crying at me I need more oxygen.

Yeah, combination of how much you can breathe in

and then how much oxygen you can pump round in your circulation, it

can no longer meet that demand and that's where everything falls apart.

Right.

'Now for my results. Just how fit am I?

'This could be embarrassing.'

What we see here is, for your body weight, your VO2 max is...

Da-dum...

-..35 mils per kilo per minute.

-OK.

I'm a little bit disappointed because, three years ago when I

did this test it was about the same, maybe 35, 36, so...

I think that's good, then.

Beyond the age of about 40 or so

you would expect VO2 max to just slowly decline as you get older

and older, so, as the years have gone on maybe the training that

you do is just allowing you to stay in a steady state.

So, 35. Is that OK for a bloke my age?

It's absolutely fine.

'Fine, but not particularly impressive.

'Although the strength of my heart and lungs limits how hard

'I can cycle, my red cells also matter.

'Time to watch them in action.'

What have we got here. Am I on here?

You're going to sit down or lie down if you will.

This is a video microscope,

so hopefully, touch wood,

we should be able to see your capillaries under your tongue.

-OK.

-We should be able to see the red blood cells

flowing through, so tip of tongue on top of your mouth and we'll just try

and find some blood vessels.

'Ned's looking for capillaries, the smallest blood vessels in my body.'

So here we can see the capillaries

and you can see different size capillaries.

All the little black dots that you can see are the individual

red blood cells floating through the capillaries,

and it's those tiny blood vessels where we see the flow going,

that is the underlying factor of oxygen delivery.

It's fascinating to watch.

They're like tiny bumper cars barging their way the narrow

streets of my circulation, delivering their cargo of oxygen.

Doesn't matter what's happening higher up, doesn't matter

what's happening with your blood pressure, doesn't matter with your

cardiac output, your heart rate, you need to have that final step,

an adequate off loading capacity to get the oxygen to your muscles.

One way to increase your red blood cell count,

and therefore your athletic performance, is to take drugs.

This is both dangerous and illegal.

The alternative is to train at altitude,

preferably very high altitude.

Dan and Ned have both spent time on Everest researching how

altitude affects the human body.

At this height, there's a lot less oxygen around.

To compensate, our body makes more red blood cells.

Fortunately, to get the same results I don't have to go to the Himalayas.

Pulse oximeter.

That's perfect...

'I just have to cross the room.'

So, put that on your finger, once you go through the door,

you're going to be in about 12% oxygen, which is

the equivalent of somewhere around 4,500 metres,

so about the summit of Mont Blanc.

OK, smells a bit funny, but otherwise...

-You're feeling all right, though?

-Yeah, yeah.

Good, excellent.

This is an altitude chamber.

I'm going to be trapped inside here for the next four hours.

So the first thing that will happen to Michael as he goes

into the chamber, is his body will sense that

there's a reduced level of oxygen in the air

and he'll begin to breathe harder and his heart

will begin to pump faster and harder.

So that will circulate more oxygen round his body, to try

and make up for the fact that there's less of it in the air.

After about an hour,

I really start to feel the effects.

My...oxygen levels are around 80%, which is pretty damned low.

I'm actually feeling very tired,

I'm doing a lot of yawning at the moment.

I'm struggling.

I feel groggy and lethargic.

But inside me, remarkable changes should already be taking place.

My body will have detected the fall in oxygen.

In response, it should have released a hormone called

erythropoietin, or EPO.

This hormone triggers the creation of new red blood cells.

-Right, that's our four hours up.

-OK.

-We can release you from here.

-Thank you.

After four hours spent at the top of Mont Blanc,

I have my blood tested.

My EPO levels have shot up

by an impressive 40%.

If I'd stayed in the chamber for a bit longer,

my red blood cells would have started to multiply.

A drug-free way to boost your blood and enhance your performance.

No wonder so many athletes train at altitude.

But there's a catch.

To make a measurable difference, I'd need to live in this chamber

for the best part of a month.

I asked my wife if she fancied keeping me company.

But strangely enough, she said no.

So, until she changes her mind, I'm going

to have to make do with the 20 trillion red cells

I have at the moment to power me through the streets of London.

Oxygen, of course, is just the beginning of the story.

Since ancient times, people have understood that blood is

a transport system.

They just had rather peculiar ideas about what was being transported.

Now, the Romans believed that blood is produced in the liver

and then spreads throughout the body carrying with it your vital spirits.

They also thought the blood somehow expressed character.

This idea still continues in our language.

We talk about people who are impetuous as being "hot-blooded".

While people who are emotionless, are, of course, "cold-blooded".

Apart from oxygen, blood does indeed carry other things.

Perhaps not vital spirits, but vital nonetheless.

Fantastic. Looks good.

'Several times a day, and without giving it a second thought,

'we load our blood with sugar and fat.'

Now, this is a sample of blood that was taken from me

a few hours after eating that greasy breakfast,

it's been spun down and you can see the red blood cells and other cells

down here, and this yellowy fluid up here, that is plasma.

Actually quite murky looking cos it's got little droplets of fat

in it from my greasy breakfast.

Now, that's slightly disturbing, isn't it?

Plasma carries the breakdown of products of food around your body.

By contrast, this is one that was taken just before I had

that breakfast and I hope you can see that the plasma is much clearer.

Plasma makes up more than half our blood

and is key to its second remarkable ability.

To absorb the mind boggling variety of substances that

come from the food we scoff,

and deliver them as energy to fuel our muscles,

raw materials to build new tissue,

or simply to be stored as big rolls of fat around our bodies.

'But how exactly do the different foods I eat change my blood,

'and what does that do to me?

'To find out, the next day I sit down

'to a very different kind of breakfast.'

Sadly, no caffeine this morning but I get the orange juice instead.

Good juice, though.

I've come to Glasgow University to see how eating

those different breakfasts has altered my blood, and me.

Now, this is an impressive piece of kit, isn't it? Wow.

This is out mass spectrometry room.

We have six mass spectrometers in here and they function

like extremely sensitive weighing scales, OK, so you put

the molecules in, and it weighs each one and lets you know what it is.

It's processing my blood from breakfast at the moment, is it?

It is, absolutely, so we've put it in this machine, it's now processing

it and this is the results that are coming out at the moment.

This is metabolomics. A novel data crunching approach to food science.

It is a radically new way to find out what different foods do

when they get inside you.

Thousands of different molecules appeared in my blood after

eating breakfast, and the fascinating part is following how

they change between the two meals.

So, what did you find?

OK, so, we looked in your plasma, we looked at thousands of

molecules and there are several hundred that are different between

the two days when you had the different breakfasts.

Some of them look quite interesting and tell interesting stories

and I could take you through...

-Yes, please.

-..some of those.

-I'm all ears.

So first, a pretty obvious one, which is glucose.

OK, so glucose looks pretty stable and what this means is

that you are able to control your sugar levels, pretty well.

That's a relief because I have a family history,

my father died of diabetes-related illnesses.

So, although this is not diagnostic, it would indicate

that your sugar levels are not bouncing about,

they're keeping fairly stable, and that's true across both breakfasts.

'Tanita also found something she wasn't expecting,

'and which she was excited by because she hadn't seen it before.

'After I ate the greasy fry-up, there was apparently

'a surge in fatty acids, called prostaglandins.

'This is a sign of inflammation in my blood vessels

'and it is not a good thing.'

If you look at day one, you have a couple of prostaglandins.

Right, those are both indicators of inflammatory...

Of inflammation, yeah.

This could have something to do with the diet that you had on day one,

so, you know, the fried egg

and the processed meats somehow inducing inflammation.

Inflammation is generally a bad thing, isn't it?

I mean, obviously I would expect the fat to go up,

but inflammation is also associated with heart disease

-and all sorts of other bad things, isn't it?

-Exactly.

What I find extraordinary is for the first time by looking

into blood you can actually tell so much about

what the food is really doing inside me.

Yeah, and what you're doing to that food,

so what you see is a combination of who you are and what you've eaten.

What is really exciting about metabolomics is

that by measuring what is going on inside our blood, it is possible to

see, for the first time, exactly what our food is doing

after we eat it.

We are, quite literally, what we eat,

and our blood's ability to carry such a vast range

of substances gives it another quality that's often overlooked.

It's nutritious.

Across the natural world, there are numerous species of animals

that feast on human blood.

Head lice.

Mosquitoes.

Leeches.

In fact, all that lot have at one time or another,

gorged on my blood, and seem to have enjoyed the experience.

Even humans sometimes drink blood.

Now, we're all familiar with the vampire myth,

but I was surprised to read that in Roman times,

drinking other people's blood was extremely popular.

What people would do is they'd go to a fight,

gladiator lying dead there, and if you had some

ailment like epilepsy, you would dash in and try and grab

a chunk of the dead gladiator's liver,

or perhaps just lick the wounds.

In fact, the reason people did this is because the gladiators

were young, they were fit and they were recently dead.

These days, we're less inclined to drink blood to cure our ailments,

but we do enjoy eating it.

Almost every national cuisine has a recipe involving animal blood.

In a playful, ghoulish mood, I've decided to make a traditional

British blood dish, with a less traditional ingredient.

My own blood.

Here we go.

Not very attractive looking,

but I've managed to get two black puddings

out of 330 mils of my blood.

This should be

actually quite nutritious, plenty of protein, lots of vitamin C and iron.

SIZZLING

Right, for those who are watching their figures you might

like to know that blood is really quite calorific. In fact, there's

almost twice as many calories per mil of blood as, say, beer.

OK, it's kind of ready to plate up, I think.

Here we go.

Black pudding a la Michael.

Mm, not bad, could do with a bit more salt, I think,

I obviously don't have very salty blood.

I don't think it's going to take off as a national dish, this.

Quite chewy.

We've seen that one of blood's primary jobs is to carry oxygen

and nutrients to every part of the body.

It does so via arteries, veins and capillaries.

And, of course, it circulates.

These days the idea that blood circulates

is as obvious as the fact the earth goes round the sun.

But it's a surprisingly recent discovery.

The Romans, believers in vital spirits, were also convinced

that blood is made fresh every day and travels only one way,

out to our fingers and toes, where it is burnt away.

It sounds bizarre to us today,

but this idea survived largely unchallenged for over 1,000 years,

until someone decided to do a rather obvious experiment.

Now, our modern understanding of the human circulatory system began

here in Bart's Hospital in the early years of the 17th century.

It began with William Harvey,

an eminent doctor and most unlikely revolutionary.

It occurred to Harvey that replenishing our blood

every day must involve making huge amounts of the red stuff.

So he decided to do an experiment.

He got hold of an animal heart.

He filled one of the chambers with water.

And then he just kind of poured it out and he measured what he'd got.

Then he did the calculation.

He took the volume of water he'd measured

and multiplied it by the number of times the heart beats.

This came to around ten litres of blood passing through

the heart every hour.

That's 240 litres of blood being

produced by your body every single day.

Now, clearly, it was vastly more blood than anyone's body could

possibly be making in a day.

The only rational explanation is that blood must be circulating.

Challenging long-held beliefs was not a good career move,

so Harvey sat on his discovery for 12 long years.

It wasn't until 1628 that he laid out his case in

his masterpiece, De Motu Cordis - On The Motion Of The Heart And Blood.

A rare copy is kept under lock and key

at the Hunterian Museum in Glasgow.

Now, this book only contains one diagram

but it is an incredibly important diagram because it shows you

one of Harvey's classic experiments, and I'm about to re-enact it.

I've got my tourniquet on over here,

I've also got a safety razor blade which he doesn't mention,

but which is useful for clearing away a few hairs.

Now, can you see here, there's a vein there?

Make it stand up a bit.

First I block the blood flow by placing my finger over the vein.

If I drain away the blood above the blockage, the vein stays empty.

But if I try and drain away blood below the blockage

it quickly refills.

There can only be one reason for this.

Blood is travelling via the veins, back up my arm, towards my heart.

This is not the world's most exciting experiment to look at

but it would in time overthrow 1,000 years of dogma

and also help launch experimental science in Europe.

Fast forward 400 years and we can now see how blood

flows through the body in ways Harvey could never have dreamt of.

Now, this is an MRI machine, and I absolutely loathe MRI machines

because I'm mildly claustrophobic.

Apparently, I'm going to be in there for almost four hours.

30 seconds.

This powerful scanner is building up a picture of all the major

blood vessels in my body.

OK, Michael, can you breathe in, please? Good. Breathe out.

Now, that is impressive. It's not the sort of thing you would

normally ever see.

This is my circulation based on hours spent in the MRI machine,

it is the major highway down which my blood travels.

What you're looking at at the moment is actually the arteries,

the high-speed network.

If you add in the minor arteries

and the veins then it gets really complicated.

Introduce the capillaries and it's almost a sold sculpture of my body,

in fact blood is so essential, every living cell in my body

lies on average just a hundredth of a millimetre from a blood vessel.

Now, that adds up to an astonishing 60,000 miles of tubing.

Enough to go round the world twice.

It looks like a vast and complex bit of plumbing,

and until recently doctors tended to treat it as nothing more

sophisticated than that.

But there is actually a secret about our circulatory system

that we are only now beginning to unravel.

If an artery supplying the heart gets blocked, then the surgeon

may try using a vein to bypass the blockage.

In time, however, the veins themselves often clog. Why?

Well, the answer came not from medicine

but from aerodynamic engineering.

Here at Imperial College in London, engineers spend their days

analysing how air flows over racing cars and aeroplane wings.

The team are now applying the techniques of aerodynamics to

study how blood flows through arteries and veins.

Peter Vincent has set up a demonstration of what can

go wrong in a common procedure -

bypass surgery.

So what am I looking at here,

this presumably represents an artery?

Yep, right's right and this represents a vein

and the entire configuration represents

something that would be formed by a clinician

artificially inside the body, such as a bypass graft.

OK, so I'm a surgeon, there's a problem further down there,

I, for example, have attached a vein here to bypass a blockage,

in, say, an artery feeding the heart.

Exactly. Yep. That's exactly what it represents.

'Now we're going to use coloured ink to simulate what happens

'when our blood tries to flow round a sharp corner.'

So we can see the ink coming through here, which gives us

an indication of the flow,

and what we notice is in this region the flow is very unsteady.

Surgeons commonly need to join blood vessels, and it turns out that

if the angle of connection is too extreme it creates

turmoil in our blood flow.

The problem with this is,

highly unsteady flow can actually aggravate the vessel wall and cause

the vessel wall to inflame, and grow inwards and block this connection,

which is clearly very bad if you've formed a bypass graft.

Right, so that causes the inside of the artery to fur up or block

or whatever, is that right?

To inflame inwards, it's an inflammatory response,

so the idea is, if we understand the flow patterns in more detail,

we can look to suppress the unsteadiness that occurs and try

and create bypasses that are, well, function for longer and last longer.

Now. Watch what happens when our tube is curved instead of straight.

With a gentler angle of connection, the flow becomes

much, much smoother.

Peter's team are exploring how the intricate curves of our blood

vessels affect the way our blood flows throughout our whole body.

What we can do is zoom in on the flow field on the fluid dynamics.

'They've been looking at how blood moves through the aorta,

'the main artery coming out of the heart.'

In the aortic arch, for example, you can see the natural twist

and curvature of the arch,

so as well as just curving around it twists and it sort of has

a helical shape, that acts to mix and swirl the blood, mix oxygen

in the blood, helps to stabilise the flow, avoid unsteadiness.

It just makes you fully appreciate

the wonders of evolution, doesn't it?

Well, yes, quite, absolutely, yeah.

So the subtle curves and shapes of our arteries aren't random.

Our circulatory system is a real wonder of natural engineering,

designed to control our blood flow with amazing precision.

And this research has inspired a very neat medical innovation.

Now, this is something called a stent, it's a nickel-titanium mesh

and what surgeons do is they use it in arteries which are partially

blocked, might be an artery feeding your heart or, say, your leg, and it

holds that artery open. The trouble is, that they get blocked up and it

turns out that part of the problem is because they are straight.

Now, this is a stent of very recent invention, if you like,

invented by a scientist here at Imperial,

and, as I hope you can see, it is actually a helix.

Now, it looks really simple,

but this is the product of 20 years research and recent

studies in humans suggest that this survives better in the body,

if you like, it's less likely to block up and fail

than a standard stent.

Beautiful piece of engineering.

Our circulatory system enables our blood to reach every organ

and every living cell in our body,

carrying its vital supplies of oxygen and food.

But it also allows our blood to do something just as important,

defend us.

I'm going to try and demonstrate what happens when your body

is injured or under attack, using a nice sharp needle which

I'm going to scratch myself with,

and this machine here, what it will

do is record the blood flow, just beneath the surface of the skin.

At the moment it's just looking sort of blue,

which suggests that nothing very exciting is going on.

Scratch there.

Oh, I was a bit enthusiastic there.

Immediately you can start to see the reaction, there is a huge increase

in blood flow to that area which is demonstrated by the sort of area of

red and orange, and what you've got is a classic inflammatory response.

My blood is rushing to the area under attack.

Now, the body's first reaction to any infection or injury is to

increase blood flow, bringing heat, swelling, redness and pain.

Today, we know inflammation is a normal response to injury

but this wasn't always the case.

For thousands of years, these symptoms were

seen as a sign that the blood was overheating, expanding.

The obvious answer was to let it escape. Bloodletting.

Gallons of blood flowed from the veins of victims

in search of relief.

Bloodletting was the most common medical practice for nearly

2,000 years.

So common you could have it done on the high street.

In medieval times, the person who cut your hair

and gave you a shave also did the bloodletting.

The reason you've got these barber poles is because the white

represents fresh clean bandages, and the red represents blood.

Originally, you'd have had a basin on top to hold the leeches

and one underneath to hold the blood.

Bloodletting may have been beneficial in a few cases,

but it certainly killed far more than it cured.

Ironically, draining overheated blood from a patient

deprived them of critical infection fighters.

White blood cells.

A healthy adult has about 40 billion of them.

They're the front-line defence force of our immune system.

Constantly battling invading microbes, such as bacteria,

viruses and fungi.

Magnified 1,000 times, the larger cells here are

my own white blood cells, swallowing little green aliens.

But the immune system is more than just a reactive defensive force,

a microscopic Dad's Army.

It can do something much more interesting.

To show you what it's capable of,

I'm about to try something that's a first for me.

White water canoeing.

The thing about your immune system is it is not only really good

at responding to danger but also at anticipating danger,

and I'm about to give it something serious to think about.

Not really looking forward to it.

'To activate the response I'm hoping to see,

'I need to do something that is stressful.'

Oh, that's cold!

'Not just physically stressful, but mentally.

'The aim is to induce a lot of stress but not actually get hurt.'

And just once.

Immunologist Doctor Natalie Riddell, from University College London,

takes generous amounts of my blood.

Right, probably have to put quite a bit of pressure on there.

I will, yeah.

While I warm up,

Natalie extracts the immune cells from my blood samples.

The cells that mobilise during the stress response tend to have

a more kind of aged characteristic, so generally as people get older

you see more of these age cells. You have very few of these, aged cells.

-Hurray.

-And seem to have quite

a young immune system.

-A young immune system.

-A young immune system.

-And that's good, is it?

-It is good.

OK, so what happened?

So here, we're looking at cells called a natural killer cell

and these cells are known to respond during psychological stress

or physical stress.

This is your baseline, so we can see we've got quite a low level.

Right, OK. That's not bad, doubling.

As you can see the peak has gone up.

'Now, that's impressive.

'Ten minutes of challenging canoeing was all it took to trigger

'a 50% increase in the proportion of natural killer cells

'in my blood stream.'

My body clearly decided after I'd jumped in the cold water,

there was a good chance I would get hurt

and primed my immune system for action.

During a stress response, not only is your cardiovascular system

activated and your energy stores are mobilised

so that you have the energy to escape whatever the threat is,

also your immune system is mobilised.

It's very smart, isn't it, because I kind of hadn't appreciated

the extent to which it anticipated threat.

I mean, it kind of obviously noticed that something odd was going on.

Is going to happen.

And it knew, if you like, that there was something

odd going on so it mobilised ready to take on.

It mobilises ready, poised, just in case, there is some

kind of injury and infection or invading organism.

Well, it's very nice to be told I've got a young immune system,

but I was really impressed by the way that my natural killer cells

sprang into action so incredibly rapidly, and it

has to be rapid because we are constantly surrounded by threats.

Our blood moves surprisingly fast.

The average cell does a round trip from our heart

to our extremities once every minute.

But this also means that if I cut myself blood can rapidly escape.

If nothing stopped it, I'd soon be in serious trouble.

A simple cut, and a short while later

up to five litres of blood would have drained away.

Fortunately, our bodies contain some really sophisticated mechanisms

for making sure that doesn't happen.

As soon as blood leaves the body, something extraordinary happens.

This is the fifth key property of our blood,

and in many ways, the most impressive.

So this is a vial of fresh human blood.

If I take the top off, and leave it, something interesting should happen.

You may not see

a particularly impressive change

but this blood has been transformed.

If I tilt it, nothing comes out.

That is a real clot,

the product in a series of complicated chemical reactions.

What's happening inside the blood is a minor marvel of evolution.

Looking at the clot magnified 5,000 times, it is a thing of beauty.

You can probably see the red cells and the white cells trapped

in the matrix, and at the heart of it all is a very special cell.

To find out more, I've come to

the William Harvey Research Institute in London,

where yet more blood is taken to isolate the cells

I'm particularly interested in.

The platelets.

The great thing about platelets is they're almost that forgotten

blood cell going round all the time in the background,

probably don't think about them too much, but,

should your blood vessel break,

should you start bleeding they're going to spring into action

and start to block up that hole and stop the blood

coming out of your blood vessels, so they're really important.

To see them in action, my sample is set to flow through a tube

that mimics a broken blood vessel, just like a cut on our body.

-Hi there.

-Hello.

OK, thank you.

'What I'm looking at is the first steps in the creation of a clot.'

Rather beautiful, aren't they? Little platelets.

This is the first time I've seen these tiny cells in action.

First, individual cells, those tiny green dots, start to stick.

Never seen them activate like this before.

They signal others to join in.

Within minutes, clumps of cells have stuck together, forming a clot.

In our body, this process begins the instant we're cut.

On the arterial side you need it to be quick, cos the blood's high

pressure and everything's moving fast, you need it to block up.

In your circulation your blood goes round once every minute,

so your whole blood volumes going round every minute so the arterial side needs to respond quickly....

-You've got a bleed, you're going to bleed to death...

-You're going to bleed very quickly.

Now you can see they've formed all these nice clusters of platelets

where they've all become activated, and will block up the holes.

Magnified 10,000 times, the platelets look like spiky balls.

When they activate, they grow these sticky fingers to cling together.

But the platelets can't stem the blood flow all by themselves.

There's another vital reaction needed to stop us bleeding to death.

And with the help of one of the deadliest animals on earth,

I should be able to show you this process happening.

Now, I've got some fresh human blood here and I've also got

some snake venom, this is actually from a fer-de-lance, which is

a South American viper.

OK, in we go.

Give it a bit of a swirl.

Within seconds, the venom has drastically altered my blood.

I think that's definitely becoming thicker and murkier, I'm actually

quite surprised that worked, with quite a small amount of venom.

Let's see what happens if I pour it in here.

You can see it kind of comes out, more in sort of globby bits, that

have kind of solidified and turned almost into a jelly-like substance.

Just imagine how much damage that would do.

The viper venom is mimicking what happens inside a cut blood vessel.

Long strands of protein are forming, thickening the liquid.

When we're cut, this same process works to our advantage,

creating a web for the platelets to stick to.

Without this emergency response, we would bleed to death,

every time we have a little cut.

But there's more to it than that.

Research by the military and others

has pointed towards unexpected healing properties in blood.

'I don't often find myself in a Kensington beauty clinic,

'but I want to test out a new treatment.'

I've come to have some blood taken.

'Sometimes called the vampire face-lift,

'PRP, platelet-rich plasma therapy,

'claims to accelerate healing and reverse the signs of ageing.

'First my blood is treated to make a concentrated

'solution of platelets in plasma.

'Next, this is injected directly into my face.'

It's actually very satisfying, isn't it,

the idea that all you're really doing is, you're not injecting

an alien drug or anything, you're just taking your own stuff, spinning

it down and then sticking it back into you, the power of blood.

Indeed, it's the elegance and simplicity

because it's the power of your own healing.

In theory, activated platelets and growth factors will trigger

a healing response in my skin, smoothing out wrinkles.

Why does this work,

when what you're effectively doing is just sticking blood back into

my face and presumably the arteries in my face are doing that anyway?

Well, two aspects, one, when you actually squeeze

the platelet-rich plasma into that area it then ignites those platelets

to open, plus you also are stimulating the area by wounding it.

Right, so I'll get a certain puffiness, a certain bruising...

You will, you will.

But that's part of the therapeutic process.

Indeed.

What would I expect to see in a few weeks' or months' time?

You'll feel a difference in the tone and texture

of your skin, hopefully become more like a baby's bum.

MICHAEL LAUGHS

I expect my face is still a bit inflamed

and blotchy as all those enriched platelets

and plasma run around inside my skin doing their magic.

I'm told that will go very quickly,

with two weeks I should see some improvement and within

a couple of months, apparently my skin is going to feel

like a baby's bottom. I look forward to it.

Now, it's been a couple of weeks since I had the platelet-rich plasma

injected into my face, and I think my skin is perhaps

a little bit smoother, though you'd have to have a look

at the before and after photographs and make your own judgment.

Call it wishful thinking, but perhaps

there's a bit of improvement.

The so-called vampire facial is part of a long tradition ascribing

extraordinary healing powers to blood.

For centuries, there have been gruesome tales of blood being

used to cure the sick and rejuvenate the old.

A 16th century Hungarian countess, Elizabeth Bathory,

believed by many to be the most prolific female murderer in history,

is said to have bathed in the blood of her slaughtered victims.

Legend has it she hoped that the fresh blood would help

her cling to her own fading beauty.

These stories and legends inspired one of the great Gothic novels

of the 19th century, Bram Stoker's Dracula.

One drop of your blood and you're bound to me.

Now, in the book, Stoker describes Dracula drinking blood

and becoming transformed from a little old man with white hair,

into a dark-haired super athlete.

Oddly enough, these dark fantasies of youthful transformation

are actually based on a glimmer of scientific truth.

In a climate-controlled vault,

deep beneath the streets of London's Piccadilly, lies

a 350-year-old record that holds the first clues.

The natural philosophers of the period

were simply interested in experimenting on everything.

In 1667, the fellows of the Royal Society oversaw a gruesome first.

Transfusing blood directly from an animal to a human.

They wanted to test whether blood could change character,

so they chose someone with a tempestuous nature.

A volunteer, Arthur Coga,

was transfused with blood from a sheep, from a lamb,

and it was thought that perhaps the hot-headed Coga, his moods

might be slightly tempered by the blood of this lowly, quiet animal.

The experiment didn't kill Coga, so from that point of view,

it's a success.

Inspired by this success, Robert Boyle,

the head of the Royal Society, proposed a string of further

experiments, to find out what else blood could do to transform.

So, here we have, "whether the colour of the hair or

"the feathers of the recipient be changed." So could you alter

the physical appearance of an animal by transfusing blood?

"What will be the operation of stocking an old

"and feeble dog with the blood of a young one, or vice versa?"

So, will it affect ageing in a dog?

These were fascinating questions, to these gentleman, based

on the fact that no-one had ever practised blood transfusion before.

In the original lamb-to-man experiment,

surprisingly enough, the man had actually survived.

Unfortunately, this single success was followed by years of failure.

Subsequent attempts at blood transfusions killed

so many people the practice was banned for nearly 200 years.

It wasn't a safe treatment until the early 20th-century discovery

that we each belong to one of four major blood groups.

A transfusion of the wrong type can be fatal.

Blood transfusions are now almost routine,

saving millions of lives every year.

But as we've learnt more about blood it has also lost

much of its mystery.

We no longer think of it as this wonderful substance

full of vital spirits, but as a commodity, like any other.

In the UK alone, nearly a million litres of blood a year

pass from donors to patients.

We now know that however much blood you transfuse,

it won't alter your personality.

But were the ancients entirely wrong?

Recent discoveries have resurrected some very old ideas

about blood's transformative power.

The story begins with two mice.

Now, this one is about a year old, which makes him

middle-aged in mouse years, whereas this rather more vigorous one

over here is about three months, something of a teenager.

Now, in a series of rather gruesome experiments done in the 1970s,

what they did, is they united the two rodents surgically.

So that the blood from the young mouse ran through the old mouse.

And when they did that they noticed, much to their surprise,

that the older mouse became much more vigorous.

Nothing much became of this research, and it was discontinued.

Until recently that is.

In the last decade, interest has been reignited.

'I've come to Geneva to meet a pioneer in this new field

'of rejuvenation research.'

Now, the idea has been around for a long time,

why has there suddenly been this recent interest?

It was really the idea of stem cells,

that was what first brought this idea

of tracking things through the blood stream,

this idea of sort of, can things

transfer from one to the other, and that ignited this whole idea.

But we didn't know stem cells existed, until pretty recently.

Stem cells are unique

because they can become many different types of cell.

This gives them the power to repair and maintain our bodies.

When we are young our stem cells are very active.

But as we age they gradually switch off.

Like human memory, the memory of a mouse gets worse with age.

This is an old mouse.

Only one of these holes leads to its nest.

After 50 seconds of searching, it still hasn't found the right one.

But watch what happens when we introduce a mouse of the same age,

that has been infused with young blood.

Amazingly, the treated mouse

finds its nest in just 24 seconds.

'When they looked at the brains of old mice treated with young blood,

'Saul and his colleagues saw even more remarkable changes.'

This is what our neurons look like when they're getting older...

'This object, which looks a bit like a shrivelled peanut,

'is an elderly neuron in an old brain.

'It has lost many of its connections to other cells.

'On the right, is a neuron from an old brain that has been given

'young blood.

'It looks completely different.'

When you give young blood you'll see that all of a sudden

the shape of the cell body becomes much more like a pyramid,

and this is where all the neurons are talking to this neuron

that's who communication occurs, learning and memory.

So something about young blood can actually change

the shape of the neuron itself.

And that is very similar to what a young neuron would look like.

Exactly, almost identical.

Something in the young blood seems to be triggering stem cells

into action, turning back the biological clock.

It's a finding that's truly staggering in its implications.

Have they done any studies in humans yet?

As of right now, no, but they are starting to have at least

some proof of principle clinical trials,

especially with people that have early signs of Alzheimer's.

So I'm lining up my sons at the moment, to donate blood.

Can you imagine the time

when people will start to sort of buy blood off young people

in order to try and, you know, reverse their memories or things

like that, or do you think it'll be something in the blood or...

I hope they don't do that.

It feels like a logical extension of, you know, capitalism, doesn't it?

My hope is that, is that we can identify maybe

the minimum amount of youthful factors

and the minimum amount of ageing factors that we have to lower,

and I think that'll be a much better way, a much more controlled way.

It's quite strange, isn't it, you have this mythology around blood

and then suddenly it turns out there is something behind it?

All through time there's been something attributed to blood,

and now, we're just looking at it from a different perspective,

from the perspective of science.

And we're actually finding out that there is something really

unique about blood.

If Saul and his colleagues are right,

then ancient myths about blood had at their heart the truth.

Perhaps there really is something in blood,

that has the ability to turn back time.

Blood is a hidden wonder of our body, an amazing, complex liquid

working to keep us healthy every second of our lives.

In recent weeks, I've certainly seen more of my own blood than

ever before.

I've probed its secrets and pushed its limits.

I've seen it adapt with every breath I take, ever meal I eat,

every time I face danger.

For me, the real power of blood is its ability to transform.

And this points towards fascinating developments in the future.

During the course of making this programme I've discovered

just why blood is feared, revered and mythologized.

I've also seen how it can be used, abused and studied,

and I think we'd all agree with the poet Goethe,

who said that "blood really is a very special juice".