Scientists identify a molecular culprit behind medical implant rejections

Every year, millions of people live fuller lives because of a medical device implanted somewhere in their body - from hip joints, to teeth, to heart valves.

Known as Foreign Body Response (FBR), inflammation and scarring around an implant is natural, but in some cases, it can severely damage healthy tissue and can even lead to death if the implant is not removed. FBR-related implant failure rates range widely among different medical devices, but reducing those rates has been difficult because scientists still don’t understand the underlying biology that causes FBR.

Now, researchers from the University of Maryland have discovered the molecular basis for FBR, identifying a key biological pathway that future drug therapies could target to reduce the risk of implant rejection.

Shaik O. Rahaman, an associate professor in the Department of Nutrition and Food Science in the College of Agriculture and Natural Resources at UMD, and his colleagues identified a specific cellular signaling system that kicks in when the body recognises the inherent difference in stiffness between an implant and the surrounding tissue. This system detects the mismatch and triggers inflammation and scarring, which is part of the body’s normal defense system. But in FBR, the signaling system can set up a cycle of chronic inflammation and continual scar-tissue build-up that leads to implant rejection.  

“This is a huge leap forward in this field,” Rahaman said. “So far, the medical industry has been making biomedical implants randomly, out of materials they think might work without knowing the molecular basis of the foreign body response that leads to rejection. We don’t know why it happens, and until we do, we can’t effectively develop strategies to prevent it.”

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Source: College of Agriculture and Nature Resources, 19 January 2023