Increased plasma levels of neuropeptide Y in hepatorenal syndrome

Background/Aims: To investigate the relationship between neuropeptide Y (NPY), a potent renal vasoconstrictor peptide released upon marked stimulations of sympathetic nervous system (SNS), and renal and circulatory function in cirrhosis. Methods: Plasma levels of NPY (radioimmunoassay) and norepinephrine and renal function parameters were determined in 17 healthy controls, nine patients with cirrhosis without ascites, and 37 patients with cirrhosis and ascites, of whom 12 had hepatorenal syndrome (HRS). Results: Patients with ascites showed circulating levels of NPY similar to those of patients without ascites and controls (73±4, 76±4 and 68±4 pmol/l, respectively; NS). However, patients with HRS had significantly increased levels of NPY with respect to the other groups (110±6 pmol/l; P<0.001). NPY levels correlated inversely with renal plasma flow and glomerular filtration rate and directly with norepinephrine. In patients with HRS (n=6) treatment with terlipressin and albumin was associated with a marked improvement in circulatory and renal function and marked suppression of NPY and norepinephrine levels. Conclusions: Patients with HRS have increased levels of NPY which are related to circulatory dysfunction and SNS activation and may contribute to renal vasoconstriction.