Volume 6 Supplement 1

24th European Workshop for Rheumatology Research

Open Access

Histochemical detection of oxidative stress in synovial tissue: spontaneous reactive oxygen species (ROS) production by rheumatoid arthritis T cells

  • PHJ Remans1,
  • WM Fredericks2,
  • PP Tak1,
  • FC Breedveld3,
  • JM van Laar3 and
  • KA Reedquist1
Arthritis Res Ther20046(Suppl 1):64

DOI: 10.1186/ar1106

Received: 16 January 2004

Published: 24 February 2004

Background

Oxidative stress is thought to underlie the altered pathogenic behavior of T cells in rheumatoid arthritis (RA). We recently demonstrated that intracellular signaling by Ras family GTPases leads to ROS production in RA synovial fluid (SF) T cells. However, other cellular sources of ROS may cause oxidative stress in RA synovial tissue (ST).

Objectives

The study was conducted to determine whether T cells or other cells spontaneously produce ROS in RA ST, to determine the specificity of T cell ROS production in long-standing RA versus early RA and osteoarthritis (OA) T cells, and to identify signaling pathways producing ROS in RA ST and SF T cells.

Methods

ROS production was assessed using ROS-dependent polymerization of diaminobenzidine (DAB) on cryostat sections of ST from patients with long-standing RA, early RA, and OA (n = 10 patients in each group), purified RA patient peripheral blood (PB) and SF mononuclear cells, and purified T cells (n = 4), and oxidation of the dye DCF by FACS analysis of purified RA PB and SF T cells (n = 10), in the absence or presence of pharmacological inhibitors. Cryostat sections were double labelled with DAB and cell-specific antibodies to quantify ROS-producing cells.

Results

ROS production was observed in both longstanding and early RA, but not OA ST. ROS production was observed only in T cells (68%) and neutrophils (15%). In RA ST, ROS producing T cells were observed in the synovial sublining and perivascular tissue. Catalase and BAPTA-AM, but not other ROS inhibitors, blocked ROS production in ST and SF T cells. Intracellular ROS production is detected in ST of patients with RA but not OA. T cells are the major source of intra-cellular ROS production in RA ST. Conserved signaling pathways regulate ROS production in ST, SF and Jurkat T cells. ROS production is observed in recently extravasated T cells, indicating that oxidative stress is an early event affecting T cell function in the RA synovial joint.

Authors’ Affiliations

(1)
Division of Clinical Immunology and Rheumatology, AMC
(2)
Department of Cell Biology and Histology, AMC
(3)
Department of Rheumatology, LUMC

Copyright

© The Author(s) 2004

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