THE FUTURE OF BODY IMPLANTS

Abstract

There are around 415 million people suffering from diabetes around the globe, and they don't need to get their finger punctured every time their blood sugar is to be monitored or insulin to be delivered, thanks to the magical “Insulin Pumps”. All these tiny machines have is a needle and a small pump, the system is able to monitor the glucose levels, provide information to the pump and then determine the amount of insulin to be injected 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. 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. 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. Early-responding inflammatory cells, like neutrophils and macrophages, respond to the emergency call. The needle of the pump is labeled as foreign object and attacked with tiny grains that are filled with enzymes, they try t deteriorate 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. 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 (an electrically charged medical device to control heartbeat) can interrupt the electrical transmission that's crucial for their functioning. With time due to stress and workload, Synthetic knee joints might give out particles that trigger immune cells to come into action and inflame around these fragments. Unfortunately the work of immune system attack might sometime be fatal and endanger life. Research work is underway to trick the immune system into accepting the new devices that are introduced into our bodily tissues. There are implants coated with certain chemicals and drugs that somewhat downplay the response of immune system. Those basically make the implants invisible to the immune system. More implants are being made out of natural materials and in forms that directly mimic issues, 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, the implant is designed to contain ingredients that will release specific signals, and carefully tailor to bodies' immune reactions. In the future, this way of working alongside the immune system could help 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.