Your body vs. implants - Kaitlyn Sadtler

譯者: Lilian Chiu 審譯者: Carol Wang

Insulin pumps improve the lives

全世界有四億一千 五百萬名糖尿病患者，

of many of the 415 million people with diabetes around the world

當中許多人的人生之所以能改善， 是因為胰島素幫浦

by monitoring blood sugar, delivering insulin,

協助他們監控血糖，供應胰島素，

and preventing the need for constant finger-pricking and blood testing.

不再需要經常扎手指 來做血液檢驗。

These small machines include a pump and a needle, which can sense glucose levels,

這些小機器包含了 一台幫浦以及一根針，

針可以用來感測葡萄糖濃度， 將資訊回饋給幫浦，

feed back to the pump,

and then calculate how much insulin to deliver through the needle.

接著計算出要透過針 來供應多少胰島素。

But they have a catch: they’re temporary.

但有個問題：它們是暫時性的。

Within a few days, glucose sensors have to be moved and replaced.

幾天之內，就必須要移除、 替換葡萄糖感測器。

And it’s not just glucose monitors and insulin pumps that have this problem,

而且，不只是葡萄糖 監測器和胰島素幫浦，

but all bodily implants, at different time scales.

所有身體植入物都有 這個問題，只是時間不同。

Plastic prosthetic knees have to be replaced after about 20 years.

塑膠的人工膝關節用了 約二十年後就需要替換。

Other implants, such as those used for cosmetic reasons,

其他植入物，如整形植入物，

can meet the same fate in about 10.

植入後大約十年 就會面臨同樣的命運。

That isn’t just a nuisance: it can be expensive and risky.

這個狀況不只是麻煩而已： 還有金錢和風險的考量。

This inconvenience happens because of our bodies’ immune systems.

造成如此不方便的原因， 就是人體的免疫系統。

Honed by several hundred million years of evolution,

這些防禦前線經過了 數億年的磨練，

these defensive fronts

have become exceptionally good at identifying foreign objects.

已經變成特別擅長 辨視出外來物體。

Our immune systems boast

我們的免疫系統具有 琳瑯滿目的工具

an impressive arsenal of tools to tackle, intercept, and destroy

可以處理、攔截，和摧毀

anything they believe shouldn’t be there.

任何被認為不該 出現在人體內的東西。

But the consequence of this constant surveillance

但，這種持續監控的後果，

is that our bodies treat helpful implants, like insulin pumps,

就是在發現有幫助的植入物 （如胰島素幫浦）時，

with the same suspicion as they would a harmful virus or bacteria.

我們的身體會認為它們 和有害病毒或者細菌一樣可疑。

As soon as the insulin pump has been implanted in the skin,

一旦胰島素幫浦被植入到皮膚中，

its presence triggers what’s known as a “foreign body response.”

它的存在就會觸發 所謂的「異物反應」。

This starts with free-floating proteins

異物反應的最初， 在體內自由流動的蛋白質

that stick themselves to the surface of the implant.

會黏著在植入物的表面。

Those proteins include antibodies,

這類蛋白質包括抗體，

which attempt to neutralize the new object

抗體會試圖中合新的物體，

and send out a signal that calls other immune cells to the site

且會向外發送訊號， 請求其他免疫細胞到異物所在

to strengthen the attack.

來加強攻擊。

Early-responding inflammatory cells,

快速反應的炎性細胞，

like neutrophils and macrophages,

如嗜中性白血球細胞和巨噬細胞，

respond to the emergency call.

會回應緊急求援。

Neutrophils release little granules filled with enzymes

嗜中性白血球細胞會釋放出 充滿酵素的小粒子，

that try to break down the surface of the insulin pump’s needle.

並試圖分解胰島素 幫浦的針的表面。

Macrophages secrete enzymes too,

巨噬細胞也會分泌酵素，

together with nitric oxide radicals,

加上一氧化氮自由基，

which create a chemical reaction that degrades the object over time.

它可以引發化學反應， 隨時間侵蝕物體。

If the macrophages are unable to dispatch the foreign body rapidly,

如果巨噬細胞無法很快處理異物，

they fuse together, forming a mass of cells called a “giant cell.”

它們就會融合在一起，形成 一大塊細胞，叫做「巨細胞」。

At the same time, cells called fibroblasts

同時，纖維母細胞

travel to the site and begin to deposit layers of dense connective tissue.

會移動到異物所在，開始放下 好幾層稠密的連接性組織。

Those enclose the needle that the pump uses to deliver insulin

它們會包住胰島素幫浦

and test for glucose levels.

和檢測葡萄糖濃度的針。

Over time this scaffolding builds up,

隨時間，一層一層堆疊上去，

forming a scar around the implant.

在植入物周圍形成疤。

The scar functions as an almost impenetrable wall

疤的功能就像是 幾乎無法穿過的牆，

that might start to block vital interactions

可能會開始阻擋身體 和植入物之間攸關生死的互動。

between the body and the implant.

For example, scarring around pacemakers can interrupt

比如，在心律調節器 周圍的疤可能會阻斷

the electrical transmission that’s crucial for their functioning.

調節器運作所需要的電傳輸。

Synthetic knee joints may give off particles as they’re worn down,

合成人工膝關節在磨損之後， 可能會釋放出一些粒子，

causing immune cells to inflame around these fragments.

造成免疫細胞在這些 碎片周圍產生發炎。

Tragically, the immune system’s attack can even be life-threatening.

不幸的是，免疫系統的攻擊 甚至有可能會威脅到生命。

However, researchers are finding ways to trick the immune system

然而，研究者致力在尋找 能騙過免疫系統的方法，

into accepting the new devices we introduce into our bodily tissues.

讓免疫系統接受我們放入 身體組織中的新裝置。

We’ve discovered that coating implants with certain chemicals and drugs

我們發現，在植入物上面 塗上某些化學物質和藥物

can dampen the immune response.

可以減輕免疫反應。

Those basically make the implants invisible to the immune system.

這種做法可以讓免疫系統 無法發現植入物。

We’re also making more implants out of natural materials

我們也在試著使用更多 天然材料來製造植入物，

and in forms that directly mimic tissues,

且採用直接模仿組織的形式，

so that the body launches a weaker attack

讓身體發動的攻擊不會像遇到

than it would if it came across a completely artificial implant.

完全人造的植入物時那麼強烈。

Some medical treatments involve implants

在一些醫療治療方式中 所用到的植入物

designed to regenerate lost or damaged tissues.

是設計來讓失去 或受損的組織重生用的。

In those cases, we can design the implants to contain ingredients

在那些情況下， 我們可以在植入物中放入

that will release specific signals,

會放出特定訊號的成分，

and carefully tailor our bodies’ immune reactions.

並仔細地配合人體的免疫反應。

In the future, this way of working alongside the immune system

在未來，這種和免疫系統 並行的運作方式，

could help us develop completely artificial organs,

可以協助我們開發出 完全人工的器官，

totally integrative prostheses,

完全一體化的義肢，

and self-healing wound therapies.

以及自我治癒的創傷治療。

These treatments might one day revolutionize medicine–

也許有一天，這些治療 會帶來醫學革命，

and transform, forever, the bodies we live in.

並永遠徹底改變 我們賴以生存的軀體。