Discovery of calcite as a new pro-inflammatory calcium-containing crystal in human osteoarthritic synovial fluid.
Publication year
2024Source
Osteoarthritis and Cartilage, 32, 10, (2024), pp. 1261-1272ISSN
Publication type
Article / Letter to editor
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Organization
Radboudumc Extern
Internal Medicine
Journal title
Osteoarthritis and Cartilage
Volume
vol. 32
Issue
iss. 10
Page start
p. 1261
Page end
p. 1272
Subject
Internal Medicine - Radboud University Medical CenterAbstract
OBJECTIVE: We aimed to characterize calcium-containing crystals present in synovial fluid from patients with knee osteoarthritis (OA) using Raman spectroscopy, and specifically investigate the biological effects of calcite crystals. DESIGN: Thirty-two synovial fluid samples were collected pre-operatively from knee OA patients undergoing total joint arthroplasty. An integrated Raman polarized light microscope was used for identification of crystals in synovial fluid. Human peripheral blood mononuclear cells (PBMC's), human OA articular chondrocytes (HACs) and fibroblast-like synoviocytes (FLSs) were exposed to calcite crystals. Expression of relevant cytokines and inflammatory genes were measured using enzyme-linked immuno sorbent assay (ELISA) and real-time polymerase chain reaction (PCR). RESULTS: Various calcium-containing crystals were identified, including calcium pyrophosphate (37.5 %) and basic calcium phosphate (21.8 %), but they were never found simultaneously in the same OA synovial fluid sample. For the first time, we discovered the presence of calcite crystals in 93.8 % of the samples, while dolomite was detected in 25 % of the cases. Characterization of the cellular response to calcite crystal exposure revealed increased production of innate immune-derived cytokines by PBMC's, when co-stimulated with lipopolysaccharide (LPS). Additionally, calcite crystal stimulation of HACs and FLSs resulted in enhanced secretion of pro-inflammatory molecules and alterations in the expression of extracellular matrix remodeling enzymes. CONCLUSIONS: This study highlights the unique role of Raman spectroscopy in OA crystal research and identified calcite as a novel pro-inflammatory crystal type in OA synovial fluid. Understanding the role of specific crystal species in the OA joint may open new avenues for pharmacological interventions and personalized approaches to treating OA.
This item appears in the following Collection(s)
- Academic publications [245131]
- Electronic publications [132467]
- Faculty of Medical Sciences [93207]
- Open Access publications [106059]
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