Session Title: Biology and Pathology of Bone and Joint
Session Type: Abstract Submissions (ACR)
Knee osteoarthritis (OA) is a disease frequently seen in obese patients, but the relationship might be more linked to fat than to weight. A-SAA is an adipokine known to be produced by adipose tissue. Fat surrounding joints, fat within the synovium, as well as mesenchymal progenitor joint cell types might contribute to the presence of A-SAA in the joint cavity. The purposes of this work are: a) to analyse spontaneous production of A-SAA by synovial adipocyte (SA), chondrocytes and fibroblast-like synoviocytes (FLS); b) to detect A-SAA in the synovial fluid (SF) and serum of osteoarthritic patients; c) to analyse the consequences of A-SAA exposure on chondrocytes and FLS on cytokines and metalloproteinase (MMPs) production.
Synovial adipocytes, primary chondrocytes and FLS were isolated respectively from cartilage and synovial membrane obtained from knee OA patients during joint replacement. A-SAA expression level was studied by ELISA test. A-SAA levels in serum and synovial fluid were measured in knee OA (n=29) compared to matched healthy volunteers (n=35). Cytokines and MMPs were studied by ELISA test.
Endogenous A-SAA secretion was observed by dedifferenciated chondrocytes and fat synovial explants. In primary chondrocytes and FLS, A-SAA was highly and selectively expressed in the presence of glucocorticoïds and in a less extent in the presence of IL-1β. A-SAA SF levels of knee OA patients were each time higher than corresponding serum levels. Both serum and SF A-SAA levels were correlated with the Kellgren-Lauwrence grades. Lastly, in vitro, exogenous A-SAA was capable to enhance cytokines (IL-6, IL-8, GRO-a, MCP-1) and MMPs (MMP-1, MMP-3, MMP-13) expression by human chondrocytes and FLS.
1. A-SAA can be secreted by mesenchymal progenitor joint cell types: synovial adypocyte, chondrocyte and FLS. 2. However, although easily detected in the synovial fuid of osteoarthritis patients, A-SAA corresponding serum levels were each time higher suggesting a predominant systemic origin. 3. Both serum and SF levels of A-SAA were related to the severity of knee OA. 4. Systemic or local A-SAA production may act locally to enhance, at least in vitro cytokine and MMPs production. 4. A-SAA is therefore a relevant target for a tight metabolic control.
D. de Seny,
F. Quesada Calvo,
J. P. Chapelle,
M. G. Malaise,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/serum-amyloid-a-level-in-knee-osteoarthritis-systemic-andor-local-production-and-pro-inflammatory-properties-on-human-chondrocytes-and-fibroblast-like-synoviocytes/