胰岛素泵可以监测血糖、释放胰岛素，并避免了患者经常针刺指尖取血检验的麻烦，改善了全球数百万糖尿病患者的生活。但有一个问题：它们是暂时的。并非只有胰岛素泵有这个问题，其它所有的身体植入物都面临同样问题。为什么呢？凯特琳·萨德勒详述了我们的免疫系统如何对异物做出反应。
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Insulin pumps improve the lives of many of the 415 million people with diabetes around the world by monitoring blood sugar, delivering insulin, and preventing the need for constant finger-pricking and blood testing. These small machines include a pump and a needle, which can sense glucose levels, feed back to the pump, and then calculate how much insulin to deliver through the needle. But they have a catch: they’re temporary. Within a few days, glucose sensors have to be moved and replaced. And it’s not just glucose monitors and insulin pumps that have this problem, but all bodily implants, at different time scales. Plastic prosthetic knees have to be replaced after about 20 years. Other implants, such as those used for cosmetic reasons, can meet the same fate in about 10. That isn’t just a nuisance: it can be expensive and risky. 文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
全球4.15亿糖尿病患者中，很多人因胰岛素泵而改善了生活。胰岛素泵可监测血糖并释放胰岛素，避免了患者频繁指尖取血检验的麻烦。这个小机器包括一个泵、感知血糖水平并将结果返给泵的针，然后计算出针头需注射的胰岛素量。但存在一个问题：它们是暂时的。几天后，就要更换血糖感应器。并非只是血糖检测仪和胰岛素泵存在这个问题，而是所有身体植入物都有，只是时间不同而已。塑料假膝盖大约20年后就要更换，其他植入物，如美容植入物，大约10后也要更换。这不仅仅是麻烦而已：它既昂贵又有风险。文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
This inconvenience happens because of our bodies’ immune systems. Honed by several hundred million years of evolution, these defensive fronts have become exceptionally good at identifying foreign objects. Our immune systems boast an impressive arsenal of tools to tackle, intercept, and destroy anything they believe shouldn’t be there. But the consequence of this constant surveillance is that our bodies treat helpful implants, like insulin pumps, with the same suspicion as they would a harmful virus or bacteria. 文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
由于我们身体免疫系统的缘故，才会产生这些不便。经过数亿年的进化，免疫系统作为防守前锋，特别精于发现外来物。我们的免疫系统以拥有强大的工具库而闻名，可处理、拦截并摧毁它们认为身体不该有的东西。但这种不断监测的结果是，我们的身体把有用的植入物，如胰岛素泵，当做有害病毒或细菌一样怀疑。文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
As soon as the insulin pump has been implanted in the skin, its presence triggers what’s known as a “foreign body response.” This starts with free-floating proteins that stick themselves to the surface of the implant. Those proteins include antibodies, which attempt to neutralize the new object and send out a signal that calls other immune cells to the site to strengthen the attack. 文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
一旦胰岛素泵植入皮下，会立刻触发身体的排异反应。自由漂浮的蛋白质开始粘在植入物表面。这些蛋白质包括抗体，试图中和新物体，并发出信号引来其它免疫细胞以加强攻击。文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
Early-responding inflammatory cells, like neutrophils and macrophages, respond to the emergency call. Neutrophils release little granules filled with enzymes that try to break down the surface of the insulin pump’s needle. Macrophages secrete enzymes too, together with nitric oxide radicals, which create a chemical reaction that degrades the object over time. If the macrophages are unable to dispatch the foreign body rapidly, they fuse together, forming a mass of cells called a “giant cell.” At the same time, cells called fibroblasts travel to the site and begin to deposit layers of dense connective tissue. Those enclose the needle that the pump uses to deliver insulin and test for glucose levels. Over time this scaffolding builds up, forming a scar around the implant. 文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
早期反应的发炎细胞，如中性粒细胞和巨噬细胞，在接警后会首先到达。中性粒细胞释放出充满酶的小颗粒，试图破坏胰岛素泵针头的表面。巨噬细胞也会分泌酶，与一氧化氮自由基一起产生化学反应，随着时间的推移会使物体降解。如果巨噬细胞无法快速处理掉异物，它们会融合在一起，形成一团称为“巨细胞”的细胞。同时，纤维母细胞前往该部位，并开始沉积致密结缔组织层。它们封闭了胰岛素泵中用于输送胰岛素并测试血糖水平的针头。包围层逐渐形成，在植入物周围形成疤痕。文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
The scar functions as an almost impenetrable wall that might start to block vital interactions between the body and the implant. For example, scarring around pacemakers can interrupt the electrical transmission that’s crucial for their functioning. Synthetic knee joints may give off particles as they’re worn down, causing immune cells to inflame around these fragments. Tragically, the immune system’s attack can even be life-threatening. 文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
疤痕就像一面几乎无法穿透的墙，开始阻止身体和植入物间的重要交互作用。例如，心脏起搏器周围的疤痕，可能会中断对其功能至关重要的电传输。合成膝关节使用中磨损会产生颗粒，导致这些颗粒周围的免疫细胞发炎。不幸的是，免疫系统的攻击甚至可能危及生命。文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
However, researchers are finding ways to trick the immune system into accepting the new devices we introduce into our bodily tissues. We’ve discovered that coating implants with certain chemicals and drugs can dampen the immune response. Those basically make the implants invisible to the immune system. We’re also making more implants out of natural materials and in forms that directly mimic tissues, so that the body launches a weaker attack than it would if it came across a completely artificial implant. Some medical treatments involve implants designed to regenerate lost or damaged tissues. In those cases, we can design the implants to contain ingredients that will release specific signals, and carefully tailor our bodies’ immune reactions. 文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
然而，研究人员正在寻找方法诱使免疫系统接受我们引入身体组织的新设备。我们发现通过在植入物表面涂抹某些化学物质和药物，可以抑制免疫反应。这些基本上使植入物对免疫系统不可见。我们正以直接模仿组织的形式，用天然材料制作更多的植入物，比起全人造材料的植入物，身体对它的攻击要弱得多。有些医学治疗涉及植入物,旨在重建失去或受损组织。这些情况下，我们可将植入物设计为含有能够释放特定信号的成分、专为应对我们身体的免疫反应而精心定制。文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
In the future, this way of working alongside the immune system could help us develop completely artificial organs, totally integrative prostheses, and self-healing wound therapies. These treatments might one day revolutionize medicine– and transform, forever, the bodies we live in. 文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
未来，这种与免疫系协作的方式可以帮我们开发全人工器官，全集成假体和自愈的伤口疗法。这些治疗方法可能有一天会引发医学革命——并永远改变我们赖以存在的身体。文章源自：力哥爱英语（ienglish521.com）力哥爱英语-https://ienglish521.com/2692.html
