Voiceover:The pathophysiology of emphysema,
which it just means the disease crosses behind it.
How do we get from a normal lung
to having emphysema?
I would say, in a nutshell,
it's the destruction of elastin,
which is this protein in the lungs
that gives it that nice elastic quality.
Elastin, elasticity.
So, elastin kinda looks like a coil.
I think of it as a coil.
And actually if you look at the protein itself,
it looks kind of coiled like that.
And when you take a coil and you stretch it like that,
with force, and then you let it go, what happens?
It immediately snaps back into the
original shape and size, right?
Because it's elastic.
The elastin in the lungs allows
it to do just that.
So the top of a breath, the alveoli,
which are these air sacs at the end of the airway,
they look puffed up and full of air, like this.
And this is just like our stretched out coil.
And because the walls are full of elastin,
when you exhale, which is just relaxing,
the air comes out by itself and the area kind of
goes back to its original shape and size.
Kind of like that.
So there's not that much air left in here.
But, like I said, in emphysema,
all the elastin is getting destroyed
so we have fewer of these nice walls
and whatever is left, is no longer elastic.
So the top of a breath,
it might look like this.
Do you see how the partitions and stuff are gone?
But what's worse is when you let go.
Not that much changes.
It's like a spring without the elastic quality.
It's just a wire.
So when you let it go, it's just gonna sit there.
And all that air in here is further obstructed
because the airway here actually collapses.
It collapses because without the elastin
to hold it open, the pressure in the chest cavity,
that acts on the airway, collapses it.
That's why we say in emphysema,
you have obstructive lung disease
because the air is obstructed back there.
So in a normal, healthy, functioning lung
the elastin is actually normally being
broken down all the time.
So elastin is broken down by elastase
which is a protease inhibitor,
and by that we just mean something
that breaks down protein.
So the job of elastase is to cleave the elastin
so that new tissue will have room to grow.
And who's going to keep track of elastase
is something you would call alpha one antitrypsin.
It's something that's made in the liver,
and again I'm gonna use red,
because it inhibits elastase.
So if it inhibits the thing that inhibits elastin,
then the relationship here is gonna be
alpha one antitrypsin allows there to be more elastin.
It's kinda like in the ocean, if you have shrimp
here at the bottom of a food chain,
and it's eaten by a small fish.
It's eaten by, let's say, Nemo.
So, red Nemo eats fish.
And then behind it, there's a big fish.
Maybe I shouldn't call that Nemo.
So, just a big fish, let's say a shark,
eats this small fish.
So in this food chain, the relationship...
If the food chain is this simple,
then the big fish, or the shark,
allows there to be more shrimp
by eating up all the small fish.
It's kinda like that with elastin and elastase
and alpha one antitrypsin.
And our whole problem here with emphysema
is too much elastase.
Too much elastase leads to emphysema.
Now in terms of too much elastase
there are two main ways to have that.
Anytime you see "ase" here, A S E,
that's usually a protease inhibitor
so it destroys a certain kind of protein.
Number one here we have inflammation.
And any time there's inflammation in the body,
it's kind of like a war is breaking out
and all these soldiers are being recruited
and one main one is called a neutrophile.
It's a type of white blood cell that's
always in the blood and when there's inflammation,
it goes there.
And more importantly for us right now,
it's the mother of elastase.
Literally the mother because it makes elastase.
So whenever there's too much neutrophils
in an area, it's gonna go nuts making elastase.
Inflammation is usually in response to an
invading foreign thing, right?
It could be bacteria or just any kind of particles.
And in here, especially in the lungs,
the big culprit is gonna be smoking
because even though you see the smoke rising
from cigarettes looks like just air,
but it's actually made of millions
of billions of tiny little particles
that gets inhaled into the lung.
So there's inflammation all the time.
What I drew there actually looks more like
a fake cigar, but you get the point,
is that anytime you're putting extra irritants
into the area, inflammation's gonna go rampant,
and our elastase shoots up.
So number two, the second reason
is something that arises from the body itself,
which is something called
alpha one antitrypsin deficiency.
We don't have this in the lungs.
This is the equivalent of taking out
that big fish in the food chain.
So this small fish is gonna go up
without the big fish eating it
and the shrimp, poor shrimp,
they're all gonna be gone.
Now alpha one antitrypsin is made in the liver
and is coated by a gene.
And this deficiency here is related to
a defect in the gene because the gene has
a problem here and when it's made in the liver,
the antitrypsin becomes [unintelligible]
and it can't leave.
It doesn't fit through the channel
for the normal antitrypsin to leave
so this actually causes liver disease,
but in terms of the lungs,
again we have too much elastase
because it's unchecked.
And again, with the elastase going nuts here,
our elastin's gonna go down.
And you have emphysema.