Urinary adrenomedullin levels are increased and correlated with plasma concentrations in patients with Behçet's syndrome.

Abstract

The objective was to measure urinary adrenomedullin (AM) levels in patients with active or inactive Behçet's syndrome and compare them to levels in healthy control subjects. Forty-five consecutive patients with Behçet's syndrome (20 men and 25 women with a mean age of 37.7 +/- 10.8 years) and 20 age- and sex-matched healthy hospital staff volunteers as control subjects (nine men and 11 women with a mean age of 36.2 +/- 10.4 years) were studied. Urinary and plasma AM concentrations were measured by high-performance liquid chromatography. We also investigated whether disease activity correlates with urinary and plasma AM levels. The Mann-Whitney U-test was used in statistical analysis and the values were expressed as mean +/- SD. Urinary excretion of AM (pmol per mg urinary creatinine) in patients with Behçet's syndrome (81.3 +/- 35.1) was significantly higher (P < 0.001) than in control subjects (31.2 +/- 16.1). Plasma AM levels (pmol/L) in patients with Behçet's syndrome and controls were 69.1 +/- 19.2 and 20.7 +/- 11.8, respectively; the difference was significant (P < 0.001). Although active Behçet's syndrome patients (n = 22) had higher urinary AM levels (92.1 +/- 41.1) compared to inactive (n = 23; 70.8 +/- 32.2), the difference was not significant (P > 0.05). Plasma AM levels in active Behçet's syndrome patients (77.5 +/- 21.2) were also higher than in inactive (61.6 +/- 17.3), but the difference was not significant (P > 0.05). Urinary AM levels were higher in Behçet's patients than in control subjects. Urinary AM levels were correlated with plasma AM levels. The results suggest that the higher AM levels found in the urine may be produced by the kidney as a result of the stimulation of inflammation during the course of Behçet's syndrome, or may come from plasma, as plasma AM levels were increased. However, the exact sites of AM synthesis by the kidney (e.g. glomeruli, blood vessels and/or tubular cells) could not be determined in this study. Further studies in this respect are necessary.