WEBVTT

99:59:59.999 --> 99:59:59.999
Insulin pumps improve the lives

99:59:59.999 --> 99:59:59.999
of many of the 415 million people 
with diabetes around the world

99:59:59.999 --> 99:59:59.999
by monitoring blood sugar, delivering 
insulin,

99:59:59.999 --> 99:59:59.999
and preventing the need for constant 
finger-pricking and blood testing.

99:59:59.999 --> 99:59:59.999
These small machines include a pump and
a needle which can sense glucose levels;

99:59:59.999 --> 99:59:59.999
feed back to the pump;

99:59:59.999 --> 99:59:59.999
and then calculate how much insulin 
to deliver through the needle.

99:59:59.999 --> 99:59:59.999
But they have a catch: they’re temporary.

99:59:59.999 --> 99:59:59.999
Within a few days, glucose sensors have to
be moved and replaced.

99:59:59.999 --> 99:59:59.999
And it’s not just glucose monitors and 
insulin pumps that have this problem,

99:59:59.999 --> 99:59:59.999
but all bodily implants, 
at different time scales.

99:59:59.999 --> 99:59:59.999
Plastic prosthetic knees have to be 
replaced after about 20 years.

99:59:59.999 --> 99:59:59.999
Other implants, such as those used for 
cosmetic reasons,

99:59:59.999 --> 99:59:59.999
can meet the same fate in about 10.

99:59:59.999 --> 99:59:59.999
That isn’t just a nuisance: it 
can be expensive and risky.

99:59:59.999 --> 99:59:59.999
This inconvenience happens because of 
our bodies’ immune systems.

99:59:59.999 --> 99:59:59.999
Honed by several hundred million 
years of evolution,

99:59:59.999 --> 99:59:59.999
these defensive fronts have become

99:59:59.999 --> 99:59:59.999
exceptionally good at identifying
foreign objects.

99:59:59.999 --> 99:59:59.999
Our immune systems boast an impressive 
arsenal

99:59:59.999 --> 99:59:59.999
of tools to tackle, intercept, and destroy

99:59:59.999 --> 99:59:59.999
anything they believe shouldn’t be there.

99:59:59.999 --> 99:59:59.999
But the consequence of this constant 
surveillance

99:59:59.999 --> 99:59:59.999
is that our bodies treat helpful 
implants, like insulin pumps,

99:59:59.999 --> 99:59:59.999
with the same suspicion as they would
a harmful virus or bacteria.

99:59:59.999 --> 99:59:59.999
As soon as the insulin pump has been 
implanted in the skin,

99:59:59.999 --> 99:59:59.999
its presence triggers what’s known as a
“foreign body response.”

99:59:59.999 --> 99:59:59.999
This starts with free-floating proteins

99:59:59.999 --> 99:59:59.999
that stick themselves to the surface 
of the implant.

99:59:59.999 --> 99:59:59.999
Those proteins include antibodies,

99:59:59.999 --> 99:59:59.999
which attempt to neutralize the new object

99:59:59.999 --> 99:59:59.999
and send out a signal that calls other 
immune cells to the site

99:59:59.999 --> 99:59:59.999
to strengthen the attack.

99:59:59.999 --> 99:59:59.999
Early-responding inflammatory cells,

99:59:59.999 --> 99:59:59.999
like neutrophils and macrophages,

99:59:59.999 --> 99:59:59.999
respond to the emergency call.

99:59:59.999 --> 99:59:59.999
Neutrophils release little granules filled
with enzymes

99:59:59.999 --> 99:59:59.999
that try to break down the surface 
of the insulin pump’s needle.

99:59:59.999 --> 99:59:59.999
Macrophages secrete enzymes too,

99:59:59.999 --> 99:59:59.999
together with nitric oxide radicals,

99:59:59.999 --> 99:59:59.999
which create a chemical reaction that 
degrades the object over time.

99:59:59.999 --> 99:59:59.999
If the macrophages are unable to dispatch 
the foreign body rapidly,

99:59:59.999 --> 99:59:59.999
they fuse together, forming a mass of 
cells called a “giant cell.”

99:59:59.999 --> 99:59:59.999
At the same time, cells called fibroblasts

99:59:59.999 --> 99:59:59.999
travel to the site and begin to deposit
layers of dense connective tissue.

99:59:59.999 --> 99:59:59.999
Those enclose the needle that the pump 
uses to deliver insulin

99:59:59.999 --> 99:59:59.999
and test for glucose levels.

99:59:59.999 --> 99:59:59.999
Over time this scaffolding builds up,

99:59:59.999 --> 99:59:59.999
forming a scar around the implant.

99:59:59.999 --> 99:59:59.999
The scar functions as an almost 
impenetrable wall

99:59:59.999 --> 99:59:59.999
that might start to block vital 
interactions

99:59:59.999 --> 99:59:59.999
between the body and the implant.

99:59:59.999 --> 99:59:59.999
For example, scarring around pacemakers
can interrupt

99:59:59.999 --> 99:59:59.999
the electrical transmission that’s 
crucial for their functioning.

99:59:59.999 --> 99:59:59.999
Synthetic knee joints may give off 
particles as they’re worn down,

99:59:59.999 --> 99:59:59.999
causing immune cells to inflame 
around these fragments.

99:59:59.999 --> 99:59:59.999
Tragically, the immune system’s attack
can even be life-threatening.

99:59:59.999 --> 99:59:59.999
However, researchers are finding ways 
to trick the immune system

99:59:59.999 --> 99:59:59.999
into accepting the new devices we 
introduce into our bodily tissues.

99:59:59.999 --> 99:59:59.999
We’ve discovered that coating implants 
with certain chemicals and drugs

99:59:59.999 --> 99:59:59.999
can dampen the immune response.

99:59:59.999 --> 99:59:59.999
Those basically make the implants 
invisible to the immune system.

99:59:59.999 --> 99:59:59.999
We’re also making more implants 
out of natural materials

99:59:59.999 --> 99:59:59.999
and in forms that directly mimic tissues,

99:59:59.999 --> 99:59:59.999
so that the body launches a weaker attack

99:59:59.999 --> 99:59:59.999
than it would if it came across a 
completely artificial implant.

99:59:59.999 --> 99:59:59.999
Some medical treatments involve implants

99:59:59.999 --> 99:59:59.999
designed to regenerate lost 
or damaged tissues.

99:59:59.999 --> 99:59:59.999
In those cases, we can design the implants
to contain ingredients

99:59:59.999 --> 99:59:59.999
that will release specific signals,

99:59:59.999 --> 99:59:59.999
and carefully tailor our bodies’
immune reactions.

99:59:59.999 --> 99:59:59.999
In the future, this way of working
alongside the immune system

99:59:59.999 --> 99:59:59.999
could help us develop completely 
artificial organs,

99:59:59.999 --> 99:59:59.999
totally integrative prostheses,

99:59:59.999 --> 99:59:59.999
and self-healing wound therapies.

99:59:59.999 --> 99:59:59.999
These treatments might one day 
revolutionize medicine–

99:59:59.999 --> 99:59:59.999
and transform, forever, 
the bodies we live in.