The atrial natriuretic peptide-renin-aldosterone system in hepatorenal syndrome.

BACKGROUND

Hepatorenal syndrome (HRS) is a functional acute renal failure occurring in patients with advanced liver disease: the etiology of HRS is still unknown, but a role in its development and maintaining is played by the atrial natriuretic peptide-renin-aldosterone system. Aim of the study was to investigate the circulating plasma levels of the atrial natriuretic peptide (pANP), plasma renin activity (PRA) and plasma aldosterone (pA) in a group of HRS patients, compared to healthy controls.

METHODS

Venous blood samples were drawn at 8:00 am in 36 healthy controls and in 20 patients with HRS following liver cirrhosis for the radioimmunoassay measurement of the circulating pANP, PRA and pA levels. The mean values of each variable were compared between the two groups by the "t" test; linear regression analysis was used to correlate the values of pANP and PRA, pANP and pA, and PRA and pA in the two groups.

RESULTS

HRS patient presented significant (p < 0.05) higher levels of pANP, PRA and pA than controls. Significant (p < 0.001) relations were found in healthy subjects between pANP and PRA (r = -0.78), pANP and pA (r = -0.68), and PRA and pA (r = 0.71), whereas the HRS group have only a significant (p < 0.001) positive relation between pANP and PRA (r = 0.67).

CONCLUSIONS

These data indicate that HRS is not due to a deficiency in circulating pANP. The elevated pANP levels in HRS may suggest a renal insensitivity to its natriuretic effects, and the derangement in the relationships and function in the atrial natriuretic peptide-renin-aldosterone system could be considered an important pathophysiologic mechanism in the hydro-electrolyte unbalance of HRS.