Debris, Wear, and Cellular Pathways (written by Elizabeth Hofheinz @ OTW)
Now researchers at Montefiore Medical Center and Albert Einstein College of Medicine of Yeshiva University have identified a number of cellular pathways that are involved in this response to the debris resulting from everyday use and wear which often result in pain, damage and inflammation. These findings are summarized in a review paper published in the October 2011 print edition of Nature Reviews: Rheumatology.
When asked what they were surprised to learn, co-author Neil J. Cobelli, M.D., Chairman of the Department of Orthopaedic Surgery at Montefiore Medical Center and Professor of Clinical Surgery at Einstein, told OTW,
There was a fairly good working understanding of the end result – that small particles of wear debris can cause loss of bone around a prosthesis. Some of the cell types involved were also known. However, we have identified several precise cellular mechanisms that lead to a common set of inflammatory processes resulting in the up regulation of bone resorption. It had been hoped that smaller particles of debris might be less reactive but that does not appear to be true.
Co-author Laura Santambrogio, M.D., Ph.D., Associate Professor of Pathology, Immunology and Microbiology at Einstein, told OTW, We were surprised to learn 1) how multifaceted the immune response to these wear debris is; 2) how the immune system uses different pathways to interact with polymers and particles generated by wear and tear of the implant and; 3) how sophisticated the immune recognition is of big and small wear debris particles and how they all come together in promoting aseptic osteolysis.”
As for where they go from here, Dr. Cobelli commented to OTW, “We will be looking at these same processes with more emphasis on studying metal on metal debris. It is hoped that with a better understanding of the process causing osteolysis, materials after joint replacement can be modified in such a way as to be less reactive.”
Dr. Laura Santambrogio added,
The hope is that this information will help in developing new devices with biophysical properties which would decrease the susceptibility of an inflammatory response. For example, cross-linking the biomaterial during the molding of the implant devices to increase stability and decrease the risk of wear debris formation, or embedding the biomaterial with antioxidant such as Vitamin E, which decrease the polymer oxidation, one of the main cause of the inflammatory response.