Increased activity of guanosine 3'-5'-cyclic monophosphate phosphodiesterase in the renal tissue of cirrhotic rats with ascites

A possible defect of guanosine 3'-5'-cyclic monophosphate (cGMP) content in the renal tissue caused by an increased activity of cGMP phosphodiesterase (PDE) has, so far, not been evaluated in the pathogenesis of renal resistance to endogenous natriuretic peptides (ENP) in cirrhosis with ascites. To test this hypothesis the activity of cGMP-PDE and the concentration of cGMP were evaluated in vitro in the renal tissue of 10 control rats and 10 cirrhotic rats with ascites before and after the intravenous (IV) administration of Zaprinast (Sigma, St. Louis, MO), a specific cGMP-PDE inhibitor (30 microgram/kg/min). Moreover, the effects of the intravenous administration of Zaprinast (15 microgram/kg/min and 30 microgram/kg/min) on renal plasma flow (RPF), glomerular filtration rate (GFR), and urinary sodium excretion (U(Na)V) were evaluated in 10 conscious control rats and 10 conscious cirrhotic rats with ascites. The effects of Zaprinast on plasma renin activity (PRA) was also evaluated in 10 control rats and in 10 cirrhotic rats with ascites. Finally, the effect of Zaprinast on RPF, GFR, and U(Na)V were evaluated in 10 cirrhotic rats after the IV administration of the ENP-receptor antagonist, HS-142-1. The renal content of cGMP was reduced in cirrhotic rats because of increased activity of cGMP-PDE. Zaprinast inhibited cGMP-PDE activity and increased the renal content of cGMP in these animals. The inhibition of cGMP-PDE was associated with an increase in RPF, GFR, and U(Na)V and a reduction in PRA. HS-142-1 prevented any renal effect of Zaprinast in cirrhotic rats. In conclusion, an increased activity of the cGMP-PDE in renal tissue contributes to the renal resistance to ENP in cirrhosis with ascites.

Reversal of type 1 hepatorenal syndrome with the administration of midodrine and octreotide

The aim of the study was to verify the effects of the administration of an inhibitor of the release of endogenous vasodilators together with a vasoconstrictor agent in patients with hepatorenal syndrome (HRS). This new medical perspective was compared with a traditional medical approach for HRS, such as the infusion of nonpressor doses of dopamine to produce renal vasodilation. Thirteen patients with type 1 HRS were enrolled in the study. Five of them were treated with the oral administration of midodrine and the parenteral administration of octreotide. In addition, the patients received 50 to 100 mL of 20% human albumin solution daily for 20 days. Midodrine and octreotide were dosed to obtain a stable increase of at least 15 mm Hg of mean arterial pressure. Eight patients were treated with the intravenous administration of nonpressor doses of dopamine (2-4 micrograms/kg/min) and the same daily amount of albumin. After 20 days of treatment with midodrine and octreotide, an impressive improvement in renal plasma flow (RPF), glomerular filtration rate, and urinary sodium excretion was observed in patients. This was accompanied by a significant reduction in plasma renin activity, plasma vasopressin, and plasma glucagon. No side effects were observed. Three patients were discharged from the hospital. One of them successfully underwent liver transplantation. One of the two remaining patients is still alive after 472 days with a preserved renal function, and the other died from terminal liver failure after 76 days. One of the two patients who were not discharged from the hospital successfully underwent liver transplantation, and the other died from pneumonia after 29 days. Seven out of eight patients who were treated with dopamine experienced a progressive deterioration in renal function and died during the first 12 days. Only one patient recovered renal function and underwent liver transplantation. In conclusion, the long-term administration of midodrine and octreotide seems to be an effective and safe treatment of type 1 HRS in patients with cirrhosis.

Acute effects of the oral administration of midodrine, an alpha-adrenergic agonist, on renal hemodynamics and renal function in cirrhotic patients with ascites

The effects of the acute administration of arterial vasoconstrictors on renal plasma flow (RPF) and urinary sodium excretion (UNaV) in cirrhotic patients with ascites with or without hepatorenal syndrome (HRS) are still controversial. As a consequence, vasoconstrictors are not actually used in the treatment of renal sodium retention or HRS in these patients, regardless of the several lines of evidence suggesting that these renal functional abnormalities are related to a marked arterial vasodilation. The lack of an orally available effective arterial vasoconstrictor probably represents a further reason for this omission. Consequently, the present study was made to evaluate the acute effects of the oral administration of midodrine, an orally available -mimetic drug, on systemic and renal hemodynamics and on UNaV in cirrhotic patients with ascites. Mean arterial pressure (MAP), heart rate (HR), cardiac index (CI), systemic vascular resistance (SVR), left forearm blood flow (LFBF), left leg blood flow (LLBF), RPF, glomerular filtration rate (GFR), UNaV, plasma renin activity (PRA), plasma concentration of antidiuretic hormone (ADH), and the serum levels of nitrite and nitrate (NOx) were evaluated in 25 cirrhotic patients with ascites (17 without HRS and 8 with type 2 HRS) before and during the 6 hours following the oral administration of 15 mg of midodrine. During the first 3 hours after the drug administration, a significant increase in MAP (89.6 +/- 1.7 vs. 81.80 +/- 1.3 mm Hg; P < .0001) and SVR (1, 313.9 +/- 44.4 vs. 1,121.2 +/- 60.1 dyn . sec . cm-5; P < .0001) accompanied by a decrease in HR (69 +/- 2 vs. 77 +/- 3 bpm; P < .005) and CI (2,932.7 +/- 131.4 vs. 3,152.5 +/- 131.4 mL . min-1 . m2 BSA; P < .0025) was observed in patients without HRS. No change was observed in LFBF and LLBF. The improvement in systemic hemodynamics, which was also maintained during the the 3- to 6-hour period after midodrine administration, was accompanied by a significant increase in RPF (541.5 +/- 43.1 vs. 385.7 +/- 39.9 mL . min-1; P < .005), GFR (93.1 +/- 6.5 vs. 77.0 +/- 6.7 mL . min-1; P < .025), and UNaV (92.7 +/- 16.4 vs. 72.2 +/- 10.7 microEq . min-1; P < .025). In addition, a decrease in PRA (5.33 +/- 1.47 vs. 7.74 +/- 2.17 ng . mL-1 . h; P < .05), ADH (1.4 +/- 0.2 vs. 1.7 +/- 0.2 pg . mL-1; P < .05), and NOx (33.4 +/- 5.0 vs. 49.3 +/- 7.3 micromol-1; P < .05) was found. In patients with HRS, the effects of the drug on the systemic hemodynamics was smaller and shorter. Accordingly, regardless of a significant decrease in PRA (15.87 +/- 3.70 vs. 20.70 +/- 4.82 ng . mL-1 . h; P < .0025) in patients with HRS, no significant improvement was observed in RPF, GFR, or UNaV. In conclusion, the acute oral administration of midodrine is associated with a significant improvement in systemic hemodynamics in nonazotemic cirrhotic patients with ascites. As a result, renal perfusion and UNaV also improve in these patients. By contrast, midodrine only slightly improves systemic hemodynamics in patients with type 2 HRS, with no effect on renal hemodynamics and renal function.

Q-T interval prolongation in liver cirrhosis. Reversibility after orthotopic liver transplantation

The aim of this work was to study the prevalence of Q-T prolongation in patients with liver cirrhosis and the modifications of the Q-T interval after liver transplantation. Q-T interval corrected for heart rate (QTc) and dispersion of Q-T interval were evaluated in 75 cirrhotic patients and in 24 controls by means of a 12-lead electrocardiogram. In addition, 15 patients were evaluated before and after liver transplantation. Forty-five patients (60%) had a prolonged Q-Tc. Compared with controls, both patients with alcoholic and non alcoholic cirrhosis had increased Q-Tc (414 +/- 28 msec1/2, 463 +/- 31 and 444 +/- 32 respectively; p < 0.001 and < 0.001); Q-Tc was significantly higher in alcoholic than in non-alcoholic cirrhosis (p < 0.02). Q-T dispersion was normal in cirrhotics. No correlation was found between Q-Tc interval and severity of the cirrhosis, haemodynamic variables (stroke volume, cardiac output) and s-calcium and potassium concentrations. After transplantation, Q-Tc decreased significantly (415 +/- 26 msec1/2 vs 449 +/- 31; p < 0.0001) returning to the values of the normal subjects, but no modification of the Q-T dispersion was observed. These data show that 1) prolongation of Q-T interval is frequent in cirrhosis, being higher in alcoholic than in non-alcoholic cirrhosis, 2) is not related to the severity of the disease, and 3) is reversible after transplantation.

Splenic impedance indices: a useful method to monitor patients after liver transplantation?

Splenic Doppler impedance indices are influenced, in portal hypertensive patients, by the resistance of the portal system. The aim of the study was to verify the usefulness of these indices in evaluating the presence of a pathological increase in portal resistance in patients with complications after liver transplantation. Splenic impedance indices have been evaluated in 46 patients before orthotopic liver transplantation (OLT), and 2 days, 1, 4, 8, and 12 to 18 months after transplantation. The results showed that spleen size slowly decreased after liver transplantation. From a baseline longitudinal diameter value of 18.0+/-3.6 cm (M+/-SD), the decrease was by 0%+/-3%, 8%+/-8%, 13%+/-9%, 15%+/-11%, and 14%+/-11% at 2 days and 1, 4, 8, and 12 to 18 months after liver transplantation. Splenic impedance indices-resistance index = (peak systolic - end diastolic) / peak systolic velocity; pulsatility index = (peak systolic - end diastolic) / mean velocity-which were increased before liver transplantation, showed a rapid decrease to normal values: resistance index: from 0.62+/-0.08 to 0.55+/-0.08 after 2 days, and to 0.49+/-0.09, 0.51+/-0.10, 0.54+/-0.10, 0.55+/-0.11 after 1, 4, 8, 12-18 months; pulsatility index: from 0.96+/-0.21 to 0.82+/-0.17 after 2 days, and to 0.69+/-0.19,0.72+/-0.21, 0.81+/-0.26, 0.84+/-0.26 after 1, 4, 8, and 12 to 18 months. Patients who had a good outcome, without any major complications, showed a clear and steady decrease in splenic impedance indices. On the contrary, patients who had complications affecting portal resistance (e.g., acute rejection, relapse of chronic hepatitis C virus-related hepatitis or cirrhosis, stenosis of portal anasthomosis, portal thrombosis), showed a lack of decrease, or, after an initial decrease, a subsequent re-increase in splenic impedance indices to pathological values. Splenic impedance indices measured in patients with complications were higher than those of patients without complications (P < .0004). Specificity and sensitivity of splenic impedance indices in the evaluation of the presence of complications increasing portal resistance were good. In conclusion, after OLT, splenic impedance indices could be useful aspecific parameters for identifying patients with complications that are able to affect or increase portal resistance.