Elevated serum SP is a common feature of RA patients, which also appears to correlate with clinical measurements of disease activity and with subjective clinical data (NTJ and VAS).
The aims of this study were to investigate 1) whether tachykinins are produced by synovial MCs and whether production differs in RA and osteoarthritis (OA) patients, and 2) what is the responsible receptor for SP in synovial MCs.
ELISA analyses revealed both SP and BN/GRP to be present in synovial tissue extracts and that synovial levels of SP were higher in RA patients than those with OA.
Observations favouring the occurrence of local production and marked effects of bombesin/gastrin-releasing peptide in the synovial tissue of the human knee joint--comparisons with substance P and the NK-1 receptor.