Synovial Fluid Analysis and Microscopic Assessment of Macrophage Quantities and Morphology in Equine Septic Arthritis.
Abstract: Research and provision of data on macrophages by cytological synovial fluid analysis and light microscopy in horses with septic arthritis MATERIAL AND METHODS: Records of 167 synovial fluid samples were evaluated and subdivided into different groups: (1) non-septic, (2) haematogenous septic arthritis in foals and (3) traumatic/iatrogenic septic arthritis. The effect of joint lavage on synovial fluid cytology and on the occurrence of macrophage phenotypes was investigated. Results: Regardless of aetiology and age of the horse, macrophage concentrations in synovial sepsis are decreased to a median of 5-6 % (unaffected joints: 23.5 %) and further diminished by joint lavage. Microscopic assessment led to the identification of 4 phenotypes. Morphological characteristics of type 1 showed similarities to monocytes and predominated in unaffected and in septic joints after lavage. Conclusions: Macrophages are highly versatile by altering their phenotype. A morphological assessment by light microscopy is easily applicable. Type 1 presumably contributes to joint homeostasis. Unassigned: Erfassung von Daten über Makrophagen durch zytologische Synoviaanalyse und Lichtmikroskopie bei Pferden mit septischer Arthritis MATERIAL UND METHODEN: 167 Synovialpunktate und zugehörige Patientenakten wurden ausgewertet und in 3 Gruppen eingeteilt: (1) nicht septisch, (2) hämatogen septische Arthritis beim Fohlen und (3) traumatisch/iatrogen verursachte septische Arthritis. Der Einfluss arthroskopischer Gelenkspülung auf die Synoviaanalyse und auf Makrophagen-Phänotypen wurde gruppenspezifisch untersucht. Unassigned: Unabhängig von Ätiologie und Alter des Pferdes sinkt der Anteil synovialer Makrophagen bei septischer Arthritis auf Medianwerte von 5–6 % (nicht septisch: 23,5 %) und wird durch Gelenkspülung weiter verringert. Lichtmikroskopisch wurden 4 Makrophagen-Phänotypen identifiziert. Typ 1 weist morphologische Ähnlichkeiten zu Monozyten auf und überwiegt in nicht erkrankten Gelenken sowie nach Lavage. Unassigned: Die Plastizität von Makrophagen zeigt sich durch Alternierung ihres lichtmikroskopisch leicht beurteilbaren Phänotyps. Typ 1 trägt vermutlich zur intraartikulären Homöostase bei.
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Publication Date: 2022-12-14 PubMed ID: 36516823DOI: 10.1055/a-1956-5245Google Scholar: Lookup
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- Journal Article
Summary
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This study investigates the quantities and types of macrophages present in the synovial fluid of horses with septic arthritis, in an effort to better understand this disease and its impact on joint health. It was discovered that synovial sepsis in horses, regardless of cause or age, significantly reduces the concentration of macrophages, and this decrease is further amplified by joint lavage.
Materials and Methods
- The research used records of 167 synovial fluid samples, which were evaluated and divided into three distinct groups based on the nature of their condition. These groups were: non-septic, haematogenous septic arthritis (occurring in foals), and traumatic/iatrogenic septic arthritis.
- The study design aimed to investigate the impact of joint lavage, a method of cleansing a joint usually during arthroscopy, on both synovial fluid cytology (the study of cells) and the occurrence of different macrophage phenotypes. Macrophages are immune cells that engulf and digest foreign substances, bacteria, and dead or dying cells.
Results
- Unlike healthy joints, where macrophages make up about 23.5% of the total cell count, the count in septic instances dropped to about 5-6%. Joint lavage further reduced these numbers.
- Microscopy helped in the identification of four different phenotypes of macrophages. The distinctive characteristics of the first macrophage phenotype type were similar to those of monocytes, a type of white blood cell. This type was most prominent both in healthy joints and in septic joints after a joint lavage.
Conclusions
- The research highlighted the adaptability of macrophages. These immune cells showcase their versatility by changing their phenotype (observable traits).
- Morphological assessment of the macrophages, through light microscopy, was found to be a straightforward process that can be easily applied.
- The first type of macrophage phenotype presumably contributes to maintaining joint health (joint homeostasis). Further research is suggested for a deeper understanding of this role.
Cite This Article
APA
Strootmann T, Spitzbarth I, Della Tommasa S, Brehm W, Köller G, Troillet A.
(2022).
Synovial Fluid Analysis and Microscopic Assessment of Macrophage Quantities and Morphology in Equine Septic Arthritis.
Tierarztl Prax Ausg G Grosstiere Nutztiere, 50(6), 377-385.
https://doi.org/10.1055/a-1956-5245 Publication
Researcher Affiliations
- Department for Horses, Faculty of Veterinary Medicine, Leipzig University.
- Institute for Veterinary Pathology, Faculty of Veterinary Medicine, Leipzig University.
- Department for Horses, Faculty of Veterinary Medicine, Leipzig University.
- Department for Horses, Faculty of Veterinary Medicine, Leipzig University.
- Department for Horses, Faculty of Veterinary Medicine, Leipzig University.
- Clinic for Horses, Faculty of Veterinary Medicine, Ludwig-Maximilians-University.
MeSH Terms
- Horses
- Animals
- Synovial Fluid
- Horse Diseases
- Arthritis, Infectious / veterinary
- Therapeutic Irrigation / veterinary
- Macrophages
Conflict of Interest Statement
The authors declare no conflict of interest.
Citations
This article has been cited 1 times.- Giarritiello F, De La Motte LR, Drago L. Viscosupplementation and Synovial Fluid Rheology: A Hidden Risk for Bacterial Biofilm Formation in Joint Infections?. Microorganisms 2025 Mar 21;13(4).
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