Abstract | OBJECTIVE:
Synovitis associated with osteoarthritis (OA) is directly responsible for several clinical symptoms and reflects OA's structural progression. This study sought to analyze the expression of proinflammatory mediations, including Interleukin (IL)-17 and IL-22, which play key roles in regulating inflammatory processes, in inflamed and non-inflamed areas of osteoarthritic synovium. METHODS: Synovium from knees of 32 OA patients were collected at surgery. Macroscopic evaluation of inflammation enabled inflamed and non-inflamed areas to be separated. Samples were incubated to obtain tissue- conditioned media. Quantitative mRNA expression of proinflammatory mediators was analyzed by RT-PCR and protein levels by ELISA and gelatin zymography. Immunohistochemistry and histology were performed. RESULTS: Inflamed synovium were characterized by increased leukocyte infiltration and a higher vessel-to-tissue area ratio than non-inflamed tissues. Macrophages, T and B lymphocytes, and some neutrophils were found only in the inflamed tissue, and only in the subintimal layer. Levels of proinflammatory cytokines and MMP-9 were significantly higher in tissue- conditioned media from inflamed than non-inflamed tissues. Inflamed areas were associated with higher expression of IL-17 and IL-22, both correlated with the combined release of IL-6, IL-23, and TGFβ1. CONCLUSION: Our results showed that inflammatory cytokines, including IL-17 and IL-22, are expressed at higher levels by inflamed OA synovium and suggest IL-22 involvement in OA pathophysiology. This study will help identify new therapeutic strategies for OA, especially the targeting of IL-22 to decrease inflammation.
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Authors | C Deligne, S Casulli, A Pigenet, C Bougault, L Campillo-Gimenez, G Nourissat, F Berenbaum, C Elbim, X Houard |
Journal | Osteoarthritis and cartilage
(Osteoarthritis Cartilage)
Vol. 23
Issue 11
Pg. 1843-52
(Nov 2015)
ISSN: 1522-9653 [Electronic] England |
PMID | 26521730
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2014. Published by Elsevier Ltd. |
Chemical References |
- Interleukin-17
- Interleukins
- RNA
- interleukin-22
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Topics |
- Aged
- Aged, 80 and over
- Enzyme-Linked Immunosorbent Assay
- Female
- Gene Expression Regulation
- Humans
- Immunohistochemistry
- Interleukin-17
(biosynthesis, genetics)
- Interleukins
(biosynthesis, genetics)
- Male
- Middle Aged
- Osteoarthritis, Knee
(complications, genetics, metabolism)
- RNA
(genetics)
- Real-Time Polymerase Chain Reaction
- Synovial Membrane
(metabolism)
- Synovitis
(etiology, genetics, metabolism)
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