Endotoxin Contributes to Artificial Loosening of Prostheses Induced by Titanium Particles

Abstract

BackgroundAseptic loosening of orthopedic implants caused by wear particles is a major cause of joint replacement failure. However, the mechanism of aseptic loosening has not yet been defined. The present study explored whether endotoxin adherent on the titanium (Ti) particles contributes to aseptic loosening.Material/MethodsLimulus amebocyte lysate detection was conducted to detect the levels of endotoxin adhered to the Ti particles. A mouse air pouches model was established and mice were divided into 4 groups and injected with phosphate-buffered saline (PBS) or Ti particles suspensions (0.1, 1, 10 mg/mL), following detection of the number of macrophages and the level of endotoxin. Scanning electron microscopy (SEM) was used to characterize the microstructures of Ti particles adhered with endotoxin.ResultsIn vitro experiments showed that the level of endotoxin adhered to the Ti particles was significantly increased after adding LPS back to these “endotoxin-free” particles. In vivo experiments showed that Ti particles injection significantly increased the number of macrophages and the level of endotoxin.ConclusionsIn conclusion, these results suggest that adherent endotoxin may play an important role in aseptic loosening induced by Ti particles.

Macrophages in aseptic loosening: Characteristics, functions, and mechanisms

“…In addition, PAMPs may also originate from bacterial colonies residing in the gastrointestinal tract, the oral cavity, or even the wounds in the skin, where these bacteria and PAMPs are occasionally transferred to the circulating blood, in turn reaching the implant ( 65 , 66 ). Evidenced by an in vivo experiment based on mouse balloon models, endotoxin in blood circulation could adhere to Ti particles and consequently induce macrophage aggregation ( 67 ).…”

The Influence of Bloom Index, Endotoxin Levels and Polyethylene Glycol Succinimidyl Glutarate Crosslinking on the Physicochemical and Biological Properties of Gelatin Biomaterials

“…Endotoxins are large and complex lipopolysaccharides that are localised at the outer membrane of Gram-negative bacteria [14,15] and are often associated with contamination of medical devices. Specifically, as endotoxins possess a high thermal stability [16] and are hard to destroy with conventional sterilisation conditions [17], residual endotoxins constitute the most significant pyrogen in parenteral drugs and medical devices [18,19] and frequently lead to post-operative complications, such as delayed tissue regeneration and homeostasis, implant failure and septic shock [20][21][22][23]. It is therefore imperative to assess residual endotoxins in medical devices, and especially in natural biomaterials that are prone to endotoxin contamination [24,25].…”