Circulating adrenomedullin levels in ankylosing spondylitis and Familial Mediterranean Fever

Abstract

Introduction Adrenomedullin (AM) is a 52-amino acid peptide with vasorelaxant properties. Apart from its roles on vascular tonus, AM can also contribute to inflammatory events. Plasma AM levels were elevated in connective tissue diseases and vasculitic disorders. Ankylosing spondylitis (AS) is a chronic inflammatory disease of the spine initiating in the sacroiliac joints. Familial Mediterranean Fever (FMF) is a hereditary disorder characterized by self-limiting acute attacks of fever and the presence of sustained subclinical inflammation in the attack-free periods. In this study, we investigated plasma AM levels in patients with AS and patients with FMF. Methods Twenty AS patients with active disease manifestations (mean age: 41.6 ± 10.9 years, female/male: 7/13), 28 FMF patients with acute attack (mean age: 27.4 ± 10.7 years, female/male: 17/11), and 26 healthy controls (mean age: 39.9 ± 5.5 years, female/male: 16/10) were enrolled in this study. AM levels were also measured in 11 FMF patients 2 months after the cessation of their attacks. AM levels of those 11 patients during their FMF attacks and attack-free periods were also compared. Results Median plasma AM levels were 23.86 (17.24–40.09) pmol/mL, 27.33 (17.24–38.52) pmol/mL, and 26.11 (17.05–37.42) pmol/mL in AS patients, FMF patients with acute attack, and healthy controls, respectively ( p > 0.05). AM levels were also similar in the attack-free periods of FMF patients [26.35 (24.35–34.14) pmol/mL]. There was no correlation between plasma AM levels and C-reactive protein, or between plasma AM levels and erythrocyte sedimentation rate. Conclusions AM does not seem to have any role in the pathogenesis of AS and FMF. Previous reports of elevated levels of AM in connective tissue disorders and vasculitic diseases are probably disease specific, and AM does not seem to be a common component of inflammatory rheumatic disorders.