Serum levels and urinary excretion of salusin-α in renal insufficiency

Salusin-alpha was recently shown to exert anti-atherosclerotic effects and its potential role as a clinical marker for atherosclerosis has been proposed. We determined serum salusin-alpha concentrations in 99 patients across a diverse range of renal functions and urinary salusin-alpha excretions in 12 patients with non-dialyzed renal failure using a highly sensitive and specific radioimmunoassay. Serum salusin-alpha concentrations in patients with moderate to advanced renal insufficiency (eGFR<30 ml/min/1.73 m(2)) were significantly lower than those with preserved renal function (eGFR>60 ml/min/1.73 m2) (6.1 +/- 2.4 pmol/l vs. 11.8 +/- 1.1 pmol/l, p<0.05). Since renal failure is frequently associated with atherosclerosis, we analyzed the relationship between serum salusin-alpha and eGFR after excluding patients with advanced atherosclerotic diseases. The serum salusin-alpha level was correlated with eGFR values (n =94, p<0.005). Patients with renal insufficiency showed reduced urinary salusin-alpha excretion, but the magnitude of the reduction was less than that for the decrease in serum salusin-alpha. Consequently, their salusin-alpha clearance often exceeded endogenous creatinine clearance levels. In conclusion, the decreased serum concentrations of salusin-alpha, an anti-atherosclerotic peptide, may be associated with impaired renal function, suggesting a potential role of decreased salusin-alpha in the acceleration of atherosclerosis in chronic kidney diseases. Urinary salusin-alpha may originate from the renal tubules, and may not necessarily represent the peptides filtered at the glomerulus. (C) 2010 Elsevier B.V. All rights reserved.