Metal Neurotoxicity: Implications for the patients
Microglia are resident macrophages of the central nervous system. They play a crucial role in brain development and homeostasis. Understanding the role of these “brain macrophages” in inflammation, biological response and brain protection is crucial.
This review describes the disruption of microglia activation and homeostasis through toxic metal ions as an important mechanism in neurodegeneration. High levels of metal ions can trigger neuroinflammation by prolonged induction of cytokines, dysregulation of signaling pathways, and the absence of sufficient anti-inflammatory mediators to alleviate the pro-inflammatory response. Additionally, microglial cell death can be induced.
However, it is not only the microglia that are affected by metals, but alterations in membrane and binding of metal ions to proteins and DNA, particularly in neurons, has been observed.
In Focus – The Importance of Material Choice
A study from the review, Woelber et al. featured the case study of a 46-year-old man who developed rapidly progressing Parkinson’s disease symptoms after MoM THA. Following revision arthroplasty using Ceramic on Poly bearings, his symptoms improved. Serum Co levels pre-revision were measured at 116mg/L, and declined after revision below 1mg/L. The authors recommended further evaluation of the possible link between Parkinson’s disease symptoms and prosthesis wear-induced hypercobaltemia.
Due to the potential role of metal ions in the development of neurodegenerative processes and diseases such as Alzheimer’s and Parkinson’s disease, further investigations on neurotoxicity are acutely needed particularly relating to metal ion exposure in joint replacement.
📖 Martínez-Hernández MI, Acosta-Saavedra LC, Hernández-Kelly LC, Loaeza-Loaeza J, Ortega A. Microglial Activation in Metal Neurotoxicity: Impact in Neurodegenerative Diseases. Biomed Res Int. 2023;2023:7389508. doi:10.1155/2023/7389508
📖 Woelber E, Van Citters DW, Steck T, Glass GA, Tower S. Explant analysis from a patient exhibiting rapid acceleration of parkinson disease symptoms and hypercobaltemia following metal-on-metal total hip arthroplasty. JBJS Case Connector. 2016;6(2).