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Published on: December 3, 2017
Activated polymorphonuclear derived extracellular vesicles are potential biomarkers of periprosthetic joint infection
Imre Sallai1, Nikolett Marton2, Attila Szatmári1
1Department of Orthopaedics, Semmelweis University, Budapest, Hungary.
Background:
Extracellular vesicles (EVs) are considered as crucial players in a wide variety of biological processes. Although their importance in joint diseases or infections has been shown by numerous studies, much less is known about their function in periprosthetic joint infection (PJI). Our aim was to investigate activated polymorphonuclear (PMN)-derived synovial EVs in patients with PJI.
Questions/Purposes:
(1) Is there a difference in the number and size of extracellular vesicles between periprosthetic joint aspirates of patients with PJI and aseptic loosening? (2) Are these vesicles morphologically different in the two groups? (3) Are there activated PMN-derived EVs in septic samples evaluated by flow cytometry after CD177 labelling? (4) Is there a difference in the protein composition carried by septic and aseptic vesicles?
Methods:
Thirty-four patients (n = 34) were enrolled into our investigation, 17 with PJI and 17 with aseptic prosthesis loosening. Periprosthetic joint fluid was aspirated and EVs were separated. Samples were analysed by nanoparticle tracking analysis (NTA) and transmission electron microscopy (TEM) and flow cytometry (after Annexin V and CD177 labelling). The protein content of the EVs was studied by mass spectrometry (MS).
Results:
NTA showed particle size distribution in both groups between 150 nm and 450 nm. The concentration of EVs was significantly higher in the septic samples (p = 0.0105) and showed a different size pattern as compared to the aseptic ones. The vesicular nature of the particles was confirmed by TEM and differential detergent lysis. In the septic group, FC analysis showed a significantly increased event number both after single and double labelling with fluorochrome conjugated Annexin V (p = 0.046) and Annexin V and anti-CD177 (p = 0.0105), respectively. MS detected a significant difference in the abundance of lactotransferrin (p = 0.00646), myeloperoxidase (p = 0.01061), lysozyme C (p = 0.04687), annexin A6 (p = 0.03921) and alpha-2-HS-glycoprotein (p = 0.03146) between the studied groups.
Conclusions:
An increased number of activated PMN derived EVs were detected in the synovial fluid of PJI patients with a characteristic size distribution and a specific protein composition. The activated PMNs-derived extracellular vesicles can be potential biomarkers of PJI.
Insights
Activated polymorphonuclear (PMN)-derived extracellular vesicles (EVs) are more numerous and have distinct characteristics in periprosthetic joint infection (PJI) patients. These EVs may serve as potential biomarkers for diagnosing PJI.
Area of Science:
- Biomedical research
- Orthopedics
- Immunology
Background:
- Extracellular vesicles (EVs) play vital roles in biological processes, including joint diseases.
- Their specific function in periprosthetic joint infection (PJI) remains underexplored.
- This study investigates activated polymorphonuclear (PMN)-derived synovial EVs in PJI patients.
Purpose of the Study:
- To compare the number and size of EVs in PJI versus aseptic loosening.
- To determine morphological differences in EVs between PJI and aseptic loosening.
- To identify activated PMN-derived EVs in septic samples and analyze protein composition differences.
Main Methods:
- Analysis of periprosthetic joint fluid from 34 patients (17 PJI, 17 aseptic loosening).
- EV separation followed by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and flow cytometry (Annexin V, CD177 labelling).
- Protein content analysis using mass spectrometry (MS).
Main Results:
- Significantly higher EV concentration and different size patterns in PJI samples compared to aseptic loosening.
- TEM confirmed vesicular nature; flow cytometry showed increased activated PMN-derived EVs in PJI.
- MS identified significant differences in protein abundance, including lactotransferrin and myeloperoxidase.
Conclusions:
- Activated PMN-derived EVs are increased in PJI synovial fluid, exhibiting unique size and protein profiles.
- These activated EVs show potential as diagnostic biomarkers for periprosthetic joint infection.
- Further research can validate these EVs for clinical PJI detection.
