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Open Access

Synovial Tissue Analysis in Clinical Studies

  • Barry Bresnihan1
Arthritis Research & Therapy19991(Suppl 1):S35

https://doi.org/10.1186/ar49

Published: 15 November 1999

Keywords

Rheumatoid ArthritisNorthern Blot AnalysisArthropathyEarly Rheumatoid ArthritisProspective Clinical Study

Full text

Synovial tissue analysis may provide new insights in studies of the clinical course and outcome, response to treatment and disease mechanisms [1]. In a prospective clinical study of acute phase serum amyloid A (A-SAA) (the principle component of amyloid deposition) in early rheumatoid arthritis (RA), strong correlations with disease activity and response to therapy were observed [2]. A-SAA production by the liver is regulated by the pro-inflammatory cytokines IL-1, TNF-α and IL-6 [3]. Little is known about A-SAA production at peripheral sites of inflammation. This study was undertaken to investigate if A-SAA is produced by inflamed synovium in RA and other arthropathies.

Synoviocytes were cultured following arthroscopic biopsy from patients with early arthritis. Total RNA was analysed for A-SAA mRNA using Northern blot analysis and RT-PCR. Immunohistochemistry was performed on frozen tissue sections using a polyclonal rabbit anti-human antibody. Using immunohistochemistry, A-SAA protein was demonstrated in the superficial layer of the synovial intima and in vascular endothelial cells. A-SAA mRNA was not detectable by Northern blot analysis in cultured synoviocytes. The RT-PCR technique, which is 100-1000 times more sensitive, resulted in the detection of constitutive expression of A-SAA. A fragment of 335 bp nucleotides was identified by RT-PCR and was verified by Southern blot analysis. A-SAA mRNA expression was investigated in cultured synoviocytes in response to inflammatory cytokines. Initial data indicates that IL-1, TNF-α and IL-6 are important regulators of A-SAA expression in these cells.

This is the first study to demonstrate A-SAA gene expression in human synovium. Local production of A-SAA, demonstrated by both RT-PCR and immunohistochemistry, suggests a physiological role for A-SAA at sites of inflammation.

Authors’ Affiliations

(1)
St. Vincent's Hospital, Dublin, Ireland

References

  1. Bresnihan B, Tak PP: Synovial tissue analysis in rheumatoid arthritis. Balliere's Clini Rheumatol. 1999, 13: 85-99.Google Scholar
  2. Cunnane G, Grehan S, Geoghegan S, et al: Serum amyloid A in the assessment of early inflammatory arthritis. J Rheumatol . 1999,Google Scholar
  3. Steel DM, Whitehead AS: The major acute phase reactants: C-reactive protein, serum amyloid P component and serum amyloid A protein. Immunology Today. 1994, 15: 81-88. 10.1016/0167-5699(94)90138-4.PubMedView ArticleGoogle Scholar

Copyright

© Current Science Ltd 2000

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