Blood serotonin and joint pain in seropositive versus seronegative rheumatoid arthritis

Abstract

AIM: To investigate whether blood serotonin (5-hydroxytryptamine) (5-HT) modulates musculoskeletal pain differently in seropositive and seronegative rheumatoid arthritis (RA). METHODS: Patients with temporomandibular joint (TMJ) involvement of seropositive RA (33 patients) or seronegative RA (28 patients) and 26 healthy individuals were included. TMJ pain, general musculoskeletal pain, plasma and serum 5-HT, acute phase reactants and thrombocyte count were investigated. RESULTS: The patients with seropositive RA had higher serum (median = 1130 nmol/l) and plasma (55 nmol/l) levels of 5-HT than the healthy individuals (704 nmol/l, p = 0.044 and 23 nmol/l, p < 0.001, respectively), and higher plasma levels of 5-HT than the seronegative patients (14 nmol/l, p < 0.001). There was no significant correlation between serum and plasma levels of 5-HT in any group. In the seropositive RA patients, positive correlations were found between serum levels of 5-HT and the number of painful mandibular movements (r(s) = 0.36, n = 33, p = 0.042), as well as pain on maximum mouth opening (r(s) = 0.41, n = 24, p = 0.047) and tenderness to digital palpation (r(s) = 0.49, n = 33, p = 0.003). In the healthy individuals, there was a negative correlation between plasma level of 5-HT and the TMJ pressure pain threshold (r(s) = -0.47, n = 20, p = 0.037). CONCLUSION: Peripheral serotonergic pain mechanisms seem to be activated by blood 5-HT in patients with seropositive RA, in contrast to seronegative patients.

Serotonin Skews Human Macrophage Polarization through HTR2B and HTR7

“…Previous reports have documented the ability of 5HT to modulate the production of numerous cytokines in mononuclear cells, monocytes, monocyte-derived dendritic cells, and ex vivo-isolated macrophages (14,48). Whereas the inhibition of TNF-a production is a general finding, the effects of 5HT on other proinflammatory cytokines and IL-10 are variable, and they appear to be cell type-dependent.…”

Influence of serotonin on the analgesic effect of granisetron on temporomandibular joint arthritis

“…14 receptor. 4,7 Á 9 Indeed, high synovial fluid levels of 5-HT in the TMJ have been associated with TMJ movement pain.…”

Immunomodulatory Effect of Sertraline in a Rat Model of Rheumatoid Arthritis

“…In patients with RA who bear the rheumatoid factor in their blood (seropositive RA), plasma concentrations of 5-HT are elevated in correlation with the high inflammatory activity compared to patients with seronegative RA [42]. However, others found that in rats, elevations in extracellular 5-HT following reuptake inhibition by fluoxetine played an essential role in decreasing mitogen-induced lymphocyte proliferation [43].…”