9:59:59.000,9:59:59.000
Insulin pumps improve the lives

9:59:59.000,9:59:59.000
of many of the 415 million people [br]with diabetes around the world

9:59:59.000,9:59:59.000
by monitoring blood sugar, delivering [br]insulin,

9:59:59.000,9:59:59.000
and preventing the need for constant [br]finger-pricking and blood testing.

9:59:59.000,9:59:59.000
These small machines include a pump and[br]a needle which can sense glucose levels;

9:59:59.000,9:59:59.000
feed back to the pump;

9:59:59.000,9:59:59.000
and then calculate how much insulin [br]to deliver through the needle.

9:59:59.000,9:59:59.000
But they have a catch: they’re temporary.

9:59:59.000,9:59:59.000
Within a few days, glucose sensors have to[br]be moved and replaced.

9:59:59.000,9:59:59.000
And it’s not just glucose monitors and [br]insulin pumps that have this problem,

9:59:59.000,9:59:59.000
but all bodily implants, [br]at different time scales.

9:59:59.000,9:59:59.000
Plastic prosthetic knees have to be [br]replaced after about 20 years.

9:59:59.000,9:59:59.000
Other implants, such as those used for [br]cosmetic reasons,

9:59:59.000,9:59:59.000
can meet the same fate in about 10.

9:59:59.000,9:59:59.000
That isn’t just a nuisance: it [br]can be expensive and risky.

9:59:59.000,9:59:59.000
This inconvenience happens because of [br]our bodies’ immune systems.

9:59:59.000,9:59:59.000
Honed by several hundred million [br]years of evolution,

9:59:59.000,9:59:59.000
these defensive fronts have become

9:59:59.000,9:59:59.000
exceptionally good at identifying[br]foreign objects.

9:59:59.000,9:59:59.000
Our immune systems boast an impressive [br]arsenal

9:59:59.000,9:59:59.000
of tools to tackle, intercept, and destroy

9:59:59.000,9:59:59.000
anything they believe shouldn’t be there.

9:59:59.000,9:59:59.000
But the consequence of this constant [br]surveillance

9:59:59.000,9:59:59.000
is that our bodies treat helpful [br]implants, like insulin pumps,

9:59:59.000,9:59:59.000
with the same suspicion as they would[br]a harmful virus or bacteria.

9:59:59.000,9:59:59.000
As soon as the insulin pump has been [br]implanted in the skin,

9:59:59.000,9:59:59.000
its presence triggers what’s known as a[br]“foreign body response.”

9:59:59.000,9:59:59.000
This starts with free-floating proteins

9:59:59.000,9:59:59.000
that stick themselves to the surface [br]of the implant.

9:59:59.000,9:59:59.000
Those proteins include antibodies,

9:59:59.000,9:59:59.000
which attempt to neutralize the new object

9:59:59.000,9:59:59.000
and send out a signal that calls other [br]immune cells to the site

9:59:59.000,9:59:59.000
to strengthen the attack.

9:59:59.000,9:59:59.000
Early-responding inflammatory cells,

9:59:59.000,9:59:59.000
like neutrophils and macrophages,

9:59:59.000,9:59:59.000
respond to the emergency call.

9:59:59.000,9:59:59.000
Neutrophils release little granules filled[br]with enzymes

9:59:59.000,9:59:59.000
that try to break down the surface [br]of the insulin pump’s needle.

9:59:59.000,9:59:59.000
Macrophages secrete enzymes too,

9:59:59.000,9:59:59.000
together with nitric oxide radicals,

9:59:59.000,9:59:59.000
which create a chemical reaction that [br]degrades the object over time.

9:59:59.000,9:59:59.000
If the macrophages are unable to dispatch [br]the foreign body rapidly,

9:59:59.000,9:59:59.000
they fuse together, forming a mass of [br]cells called a “giant cell.”

9:59:59.000,9:59:59.000
At the same time, cells called fibroblasts

9:59:59.000,9:59:59.000
travel to the site and begin to deposit[br]layers of dense connective tissue.

9:59:59.000,9:59:59.000
Those enclose the needle that the pump [br]uses to deliver insulin

9:59:59.000,9:59:59.000
and test for glucose levels.

9:59:59.000,9:59:59.000
Over time this scaffolding builds up,

9:59:59.000,9:59:59.000
forming a scar around the implant.

9:59:59.000,9:59:59.000
The scar functions as an almost [br]impenetrable wall

9:59:59.000,9:59:59.000
that might start to block vital [br]interactions

9:59:59.000,9:59:59.000
between the body and the implant.

9:59:59.000,9:59:59.000
For example, scarring around pacemakers[br]can interrupt

9:59:59.000,9:59:59.000
the electrical transmission that’s [br]crucial for their functioning.

9:59:59.000,9:59:59.000
Synthetic knee joints may give off [br]particles as they’re worn down,

9:59:59.000,9:59:59.000
causing immune cells to inflame [br]around these fragments.

9:59:59.000,9:59:59.000
Tragically, the immune system’s attack[br]can even be life-threatening.

9:59:59.000,9:59:59.000
However, researchers are finding ways [br]to trick the immune system

9:59:59.000,9:59:59.000
into accepting the new devices we [br]introduce into our bodily tissues.

9:59:59.000,9:59:59.000
We’ve discovered that coating implants [br]with certain chemicals and drugs

9:59:59.000,9:59:59.000
can dampen the immune response.

9:59:59.000,9:59:59.000
Those basically make the implants [br]invisible to the immune system.

9:59:59.000,9:59:59.000
We’re also making more implants [br]out of natural materials

9:59:59.000,9:59:59.000
and in forms that directly mimic tissues,

9:59:59.000,9:59:59.000
so that the body launches a weaker attack

9:59:59.000,9:59:59.000
than it would if it came across a [br]completely artificial implant.

9:59:59.000,9:59:59.000
Some medical treatments involve implants

9:59:59.000,9:59:59.000
designed to regenerate lost [br]or damaged tissues.

9:59:59.000,9:59:59.000
In those cases, we can design the implants[br]to contain ingredients

9:59:59.000,9:59:59.000
that will release specific signals,

9:59:59.000,9:59:59.000
and carefully tailor our bodies’[br]immune reactions.

9:59:59.000,9:59:59.000
In the future, this way of working[br]alongside the immune system

9:59:59.000,9:59:59.000
could help us develop completely [br]artificial organs,

9:59:59.000,9:59:59.000
totally integrative prostheses,

9:59:59.000,9:59:59.000
and self-healing wound therapies.

9:59:59.000,9:59:59.000
These treatments might one day [br]revolutionize medicine–

9:59:59.000,9:59:59.000
and transform, forever, [br]the bodies we live in.