Cellular Bio-corrosion of Metal Implants and Effects of Metal ions on Bone Cells and Immune Cells

Abstract

Metal implants have become essential thera-peutic tools in cranial, dental, orthopaedic and cardiovascular surgery. In most cases, the implants are well tolerated. How-ever, short term orthopaedic implant loosening and failure happens in 3- 80precondition. Especially inflamed tissues like rheumatoid arthritic joints have been shown to have increased implant failure. However, the mechanisms of implant loosen-ing are still not well understood. This study investigated cellu-lar and immune-related mechanisms that may play a role in aseptic implant loosening.

A human in vitro model has been used for this study. The interaction between metal surfaces or metal ions and immune cells or bone cells was investigated. Cell culture, immune fluorescence and electron microscopy, functional tests, flow cytometry and molecular methods were applied.

The results indicate that metal surfaces made of stainless steel, aluminum or titanium are corroded by human osteoclasts (bone resorbing cells) in vitro. The released ions are taken up by the osteoclasts and immune cells, which are affected in various ways, including induction of metal sensitivity reactions and enhanced activation of osteoclasts.

We can conclude that human osteoclasts are able to corrode metal implants and release metal ions, which have then various effects on immune cells and possible on different organs and the whole organism.