Plasma renin activity in alcoholic liver disease

Plasma renin concentration represents an independent risk factor for mortality and is associated with liver dysfunction in patients with cirrhosis

BACKGROUND AND AIM

Plasma renin concentration (PRC) is increased in patients with cirrhosis. The aims of this study were to evaluate the relation of PRC to (i) portal hypertension, (ii) degree of liver dysfunction, and (iii) survival.

METHODS

Plasma renin concentration (range 2.8-39.9 μU/mL) was measured after 30 min in supine position. Also, hepatic venous pressure gradient (HVPG), Child-Pugh (CPS), model for end-stage liver disease scores and transient elastography values (TE, Fibroscan) were evaluated at this time. Mortality was recorded during follow-up.

RESULTS

One hundred fifty cirrhotic patients (age 55 ± 11 years; 73% male; CPS A 41.3%/B 41.3%/C 17.3%) were included. Mean HVPG was 16.6 ± 6.5 mmHg. Median PRC according to CPS was A 15.45 μU/mL (95%CI 1.56-261.5), B 37.3 μU/mL (95%CI 4.29-1317.65), and C 175.3 μU/mL (95%CI 5.3-5684; P < 0.001). In patients with clinical significant portal hypertension (HVPG ≥ 10 mmHg, n = 123) median PRC was 31.2 μU/mL (95%CI 2.76-1345.4), in those without was 13.7 μU/mL (95%CI 2.7-428.2; P = 0.009). Significantly higher TE values (33.2 [13-75] vs 59.65 kPa [14.5-75]; P = 0.014) were found in patients with elevated PRC. Median follow up was 711 days (95%CI 24-1152). Twenty-two (36.1%) of the 61 patients with elevated PRC and 11 of the 89 (12.4%) with normal PRC died (P = 0.001). Median PRC was significantly higher in patients that died (83.6 μU/mL [3.39-4451.9] vs 21.5 μU/mL [2.6-1197.9]; P = 0.001). Elevated PRC (P = 0.005; HR 3.36; 95%CI 1.46-7.85), hepatocellular carcinoma (P < 0.001; HR 10.68; 95%CI 3.64-31.3), CPS B (P = 0.013; HR 3.69; 95%CI 1.31-10.4) and CPS C (P = 0.008; HR 5.36; 95%CI 1.54-18.62) emerged as independent risk factors for mortality.

CONCLUSIONS

In cirrhotic patients PRC correlates with the severity of portal hypertension and liver dysfunction. Moreover, elevated PRC represents an independent risk factor for mortality.

Sodium retention and ascites formation in a cholestatic mice model: role of aldosterone and mineralocorticoid receptor?

Renal sodium retention in experimental liver cirrhosis originates from the distal nephron sensitive to aldosterone. The aims of this study were to (1) determine the exact site of sodium retention along the aldosterone-sensitive distal nephron, and (2) to evaluate the role of aldosterone and mineralocorticoid receptor activation in this process. Liver cirrhosis was induced by bile duct ligation in either adrenal-intact or corticosteroid-clamped mice. Corticosteroid-clamp was achieved through adrenalectomy and corticosteroid supplementation with aldosterone and dexamethasone via osmotic minipumps. 24-hours renal sodium balance was evaluated in metabolic cages. Activity and expression of sodium- and potassium-dependent adenosine triphosphatase were determined in microdissected segments of nephron. Within 4-5 weeks, cirrhosis induced sodium retention in adrenal-intact mice and formation of ascites in 50% of mice. At that time, sodium- and potassium-dependent adenosine triphosphatase activity increased specifically in cortical collecting ducts. Hyperaldosteronemia was indicated by increases in urinary aldosterone excretion and in sgk1 (serum- and glucocorticoid-regulated kinase 1) mRNA expression in collecting ducts. Corticosteroid-clamp prevented induction of sgk1 but not cirrhosis-induced sodium retention, formation of ascites and stimulation of sodium- and potassium-dependent adenosine triphosphatase activity and expression (mRNA and protein) in collecting duct. These findings demonstrate that sodium retention in cirrhosis is independent of hyperaldosteronemia and of the activation of mineralocorticoid receptor.

CONCLUSION

Bile duct ligation in mice induces cirrhosis which, within 4-5 weeks, leads to the induction of sodium- and potassium-dependent adenosine triphosphatase in cortical collecting ducts, to renal sodium retention and to the formation of ascites. Sodium retention, ascites formation and induction of sodium- and potassium-dependent adenosine triphosphatase are independent of the activation of mineralocorticoid receptors by either aldosterone or glucocorticoids.

Pharmacokinetics and pharmacodynamics of irbesartan in patients with hepatic cirrhosis

The effect of hepatic impairment on the clinical pharmacology of the angiotensin II (AII) receptor antagonist irbesartan was assessed by comparing pharmacokinetic and pharmacodynamic parameters in 10 patients with hepatic cirrhosis with a matched group of 10 healthy volunteers. The pharmacokinetics and pharmacodynamics of irbesartan, 300 mg taken orally once daily, were evaluated after single- and multiple-dose (7 consecutive days) administration to normotensive subjects in an open-label, multiple-dose, parallel group study. Pharmacokinetic data obtained after administration of single and multiple doses of irbesartan showed no significant difference between the two groups in time to maximum observed plasma concentration of drug (tmax), half-life (t1/2), area under the plasma concentration-time curve (AUC), apparent oral clearance (Cl(t)/F), renal clearance (Cl(r)), and accumulation index (AI). Steady-state levels of irbesartan were reached within 3 days in both treatment groups. After irbesartan administration on day 1, mean increases from baseline in plasma AII levels and plasma renin activity (PRA) were greater in the group with cirrhosis than in the control group. On day 7, mean increases from baseline in PRA were greater in the control group than in the group with cirrhosis. No discontinuations or serious adverse events occurred during the study. The pharmacokinetics of irbesartan after repeated oral administration were not significantly affected in patients with mild-to-moderate cirrhosis of the liver. No dosage adjustment is necessary in patients with hepatic insufficiency.

Arterial underfilling does not cause sodium retention in cirrhosis

PURPOSE

To test the peripheral arterial vasodilation hypothesis of sodium retention in cirrhosis. This states that sodium retention is triggered by arterial underfilling and predicts that development of sodium retention will be associated with significant and related declines in indices of arterial filling that reverse when sodium retention resolves.

DESIGN

Longitudinal evaluation of a cohort of patients with alcoholic liver disease.

PATIENTS AND METHODS

Eighteen men, 8 of whom were studied twice, 3 three times, 2 four times, and 5 five times (40 between-study comparisons). Between 23 studies, the patients were ascites-free (Group NN). Ascites spontaneously disappeared between seven studies (Group YN), appeared between six studies (Group NY), and remained present between four studies (Group YY). Between-study changes in blood volume, arterial blood pressure, cardiac output, systemic vascular resistance, left atrial volume, left ventricular diastolic diameter, aortic root diameter, aortic blood velocity, plasma norepinephrine and atrial natriuretic factor concentrations, plasma renin activity, and urinary sodium excretion were evaluated by paired t-tests. These changes were also compared among groups by analysis of variance. In addition, correlations among the changes were sought.

RESULTS

Systolic, diastolic, and mean arterial pressures, left ventricular diastolic diameter, aortic root diameter, stroke volume, cardiac output, plasma norepinephrine concentration, and systemic vascular resistance were unchanged between studies. Left atrial volume increased between studies in Group NY. Pulse pressure fell more in Group NY than in Groups NN and YN, principally as a result of a decline in systolic blood pressure. Plasma norepinephrine concentration, plasma renin activity, and blood volume rose more in Group NY than in Groups NN, YN, and YY. Changes in both systolic and pulse pressures were directly correlated with the change in sodium excretion but unrelated to the change in plasma norepinephrine concentration. Changes in plasma norepinephrine concentration and plasma renin activity were unrelated to changes in blood pressure, systemic vascular resistance, and urinary sodium excretion.

CONCLUSIONS

None of the indices of arterial filling tested except pulse pressure were related to sodium retention. Reduced pulse pressure is inconsistent with arterial underfilling, as peripheral vasodilation instead increases pulse pressure by increasing diastolic run-off. These data do not support the hypothesis that arterial underfilling is the stimulus for sodium retention in alcoholic cirrhosis.