Serotonin levels low in ankylosing spondylitis

(HealthDay)—Patients with ankylosing spondylitis (AS) have lower serotonin levels than healthy controls and patients with rheumatoid arthritis (RA), according to a study published online Sept. 30 in the Journal of Bone and Mineral Research.

Kalliopi Klavdianou, M.D., from Patras University Hospital in Greece, and colleagues measured serum serotonin levels in 47 patients with AS, 28 with RA, and 40 healthy subjects. The authors examined the effect of serum on serotonin signaling using the human osteoblastic cell line Saos-2, and using western immunoblots to assess levels of phospho-CREB (pCREB).

The researchers found that patients with AS had lower serum levels of serotonin than healthy controls (P = 0.038) and patients with RA (P = 0.0004). Serotonin levels were significantly lower among patients with AS receiving tumor necrosis factor α (TNFα) blockers compared to those not on treatment (P = 0.019). There was an inverse correlation between serum serotonin levels and pCREB induction in osteoblast-like Saos-2 cells.

"Serotonin levels are low in patients with AS and decrease even further during anti-TNFα treatment," the authors write. "Differences in serotonin levels are shown to have a functional impact on osteoblast-like Saos-2 cells. Therefore, serotonin may be involved in new bone formation in AS."