Urotensin II and cardiomyopathy in end-stage renal disease

Circulating urotensin (UTN) is increased in patients with heart failure and in patients with renal diseases, and UTN antagonism is currently considered as a potential treatment for these conditions. Contrary to this contention, studies in end-stage renal disease suggest that, perhaps because of interference with sympathetic and NO systems, UTN may be cardioprotective. Therefore, we investigated the relationship between circulating UTN and echocardiographic parameters of left ventricular function (midwall fractional shortening), left atrial volume, and myocardial geometry (mean wall thickness and relative wall thickness) in 191 patients with end-stage renal disease. UTN was associated directly (r=0.39; P<0.001) with left ventricular systolic function and inversely with left atrial volume (r=-0.40; P<0.001) and the muscular component of the left ventricular (UTN versus mean wall thickness: r=-0.30, P<0.001; UTN versus relative wall thickness: r=-0.32, P<0.001). Adjustment for a series of 11 risk factors produced a relatively small change in the strength of these relationships. However, further adjustment for plasma norepinephrine or, particularly so, for the endogenous inhibitor of NO synthase asymmetrical dimethyl arginine produced a 33% to 50% decrease in the strength of such associations. Of note, there was a strong UTN-asymmetrical dimethyl arginine interaction in determining midwall fractional shortening (P=0.001) and mean wall thickness (P=0.006). These data support the hypothesis that high UTN is cardioprotective in end-stage renal disease and that interference by UTN with sympathetic activity and NO synthesis represents an intermediate mechanism mediating the favorable echocardiographic profile of patients with high UTN. Additional mechanistic insights may be needed before launching long-term clinical trials with UTN antagonists in patients with end-stage renal disease.