Researchers at Rush University Medical Center have identified a key immunological defense reaction to the metals in joint replacement devices, leading to loosening of the components and early failure.
The study, funded by the National Institutes of Health, won the annual William H. Harris, MD Award for scientific merit from the Orthopaedic Research Society. Currently posted online, it is expected to be published in the June issue of the Journal of Orthopaedic Research.
Over 600,000 total joint replacements are performed in the United States each year. The vast majority are successful and last well over 10 years. But in up to 10 percent of patients, the metal components loosen, requiring the patient to undergo a second surgery.
The loosening is often caused by localized inflammation, an immune reaction to tiny particles of debris from the components themselves as they rub against one another. No infection is involved.
"As soon as joint replacement devices are implanted, they begin to corrode and wear away, releasing particles and ions that ultimately signal danger to the body's immune system," said Nadim Hallab, associate professor at Rush University Medical Center and the study author.
There are two different types of inflammatory pathways: one that reacts to foreign bodies like bacteria and viruses, which cause an infection, and another that reacts to "sterile" or non-living danger signals, including ultraviolet light and oxidative stress.
This is the first time that researchers have shown that debris and ions from implants trigger this danger-signaling pathway.
According to Hallab, when specialized cells of the immune system, called macrophages, encounter this metallic debris, they "engulf it in sacs called lysosomes and try to get rid of the debris by digesting it with enzymes." But the particles damage the lysosomes, Hallab said, "and the cells start screaming 'danger.'"
These danger signals are detected by large complexes of proteins, called inflammasomes. The inflammasomes mobilize, precipitating a chain of chemical events that cause inflammation.
The researchers are hopeful that identification of this molecular pathway that triggers inflammation without infection could lead to new and specific therapeutic strategies to avoid the early failure of joint replacements.
Other researchers at Rush involved in the study were Marco Caicedo, Ronak Desai, Kyron McAllister, Dr. Anand Reddy, and Dr. Joshua Jacobs.
Sharon Butler | EurekAlert!
Further reports about: > Immune cell activation > Orthopaedic > bacteria > body's immune system > danger-signaling pathway > immune reaction > immune system > immunological defense reaction > inflammation > joint replacement devices > lysosomes > metal debris > oxidative stress > ultraviolet light > viruses
23.03.2017 | Technische Universität München
How prenatal maternal infections may affect genetic factors in Autism spectrum disorder
22.03.2017 | University of California - San Diego
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
23.03.2017 | Life Sciences
23.03.2017 | Power and Electrical Engineering
23.03.2017 | Earth Sciences