Abstracts (complete list) - Wissenschaft Online

Silvia Capellino, Peter Angele, Werner Falk, Maurizio Cutolo, Rainer H. Straub
Chromaffin-like cells and catecholamine production: role on
the inflammatory response in rheumatoid arthritis (RA)
patients
Introduction: It is well known that norepinephrine (NE) influence the immune response.
We already demonstrated that in RA synovial tissue there is a loss of sympathetic nerve
fibers compared to osteoarthritis (OA). However, there is no difference in NE release
from synovial tissue in both groups.
Aim: To identify cells positive for tyrosine hydroxylase (TH) and PGP9.5 (neuronal
marker) and to understand the role of the local catecholamine production during the
inflammatory response in RA patients.
Materials and methods: Synovial samples were obtained from OA and RA patients who
underwent knee joint replacement surgery. Tissue samples were frozen and than
analyzed for TH, PGP9.5 and synovial cell markers by doublestain-immunofluorescence.
From the same patients, synovial cells were isolated by tissue enzymatic digestion, and
cultured with Reserpine (10 -6 to 10 -8 M) or medium (control) for 24 hours.
Determination of TNFα, IL-10, IL-8 and IL-6 was performed by Luminex technique and
ELISA.
Results: Only in RA we found cells expressing PGP9.5. These cells did not doublestain
with markers for fibroblasts, macrophages, T-cells and B-cells but also express TH. The
blockade of catecholamine release by Reserpine 10 -6 M caused a reduction of TNFα by
60% compared to control cells in RA patients. In OA there was a reduced TNFα
production in Reserpine-treated cells, but the effects were lower than in RA. The
production of IL -6 and IL -8 tended to be lower in Reserpine-treated RA cells, but not in
OA.
Conclusions: We hypothesize that chromaffin-like cells are present in RA synovial tissue,
producing NE and other catecholamines, and acting on local inflammation. Our future
goal is to investigate the effects of the different catecholamines on the inflammatory
reaction.