Plasma endothelin-1 levels of children with cirrhosis

Endothelin-1/Nitric Oxide Ratio as a Predictive Factor of Response to Therapy With Terlipressin and Albumin in Patients With Type-1 Hepatorenal Syndrome

Background and Purpose

Predictors of response to type-1 hepatorenal syndrome (HRS) therapy are urgently needed. This study's purpose is to evaluate the proposed predictors in these patients.

Methods

Forty-two type-1 HRS patients with cirrhosis were treated with albumin and terlipressin. Clinical, biochemical, and demographic parameters taken at the onset of therapy and changes in endothelin-1/nitric oxide (ET-1/NO) ratio during therapy were analyzed to check their predictive value.

Results

Response to treatment (serum creatinine level <1.5 mg/dL at the end of therapy) was shown in 20 patients (48%). Independent predictive variables of response to therapy were early reduction of ET-1/NO ratio ≥0.15 at day 3 of therapy and serum bilirubin baseline <8 mg/dL (area under the receiver operating characteristic curve, 0.751; P < 0.001; specificity, 55%; sensitivity, 85%). Response rates in patients with serum bilirubin level <8 and ≥8 mg/dL were 63% and 20%, respectively (P = 0.008). The corresponding values in patients with an early reduction of ET-1/NO ratio ≥0.15 and <0.15 on day 3 were 85% and 13.6%, respectively (P < 0.001).

Conclusions

Early reduction of ET-1/NO ratio and lower serum bilirubin baseline can predict response to type-1 HRS therapy with albumin and terlipressin. Alternative therapy should be investigated for nonresponder type-1 HRS patients.

The Role of Endothelin in the Pathophysiology of Migraine-a Systematic Review

PURPOSE OF REVIEW

Vasoactive peptides play a key role in the attack-initiating cascade of migraine. Recent studies have highlighted a potentially important role for endothelin-1, a potent vasoconstrictor peptide, in migraine pathophysiology. Here, we review the current data on endothelin's involvement in migraine.

RECENT FINDINGS

We identified 23 articles. Nine studies reported on endothelin-1 plasma concentrations in patients with migraine, eight studies investigated relevant genetic associations, five studies investigated endothelin-1 and spreading depression in animals, and one randomized controlled clinical trial tested the efficacy of an endothelin antagonist in the acute treatment of migraine in patients both with and without aura. Elevated endothelin-1 plasma levels have been reported in the early phase of migraine attacks. Genetic abnormalities related to the endothelin type A receptor have been reported in migraineurs. Endothelin-1 potently induces spreading depression in animals, which may explain the connection between endothelial irritation and migraine aura. Endothelin-1 could be a primary factor in the attack-triggering cascade of migraine attacks with and without aura. Additional studies in humans and animal models are needed to further elucidate the role of endothelin-1 in migraine.

Endothelin-1 Gene Expression in Endothelial Cells Is Potently Inhibited by a Vasodilator, Dilazep

Endothelin-1 (ET-1) is considered to be involved in various cardiovascular and renal disorders. The objective of this study was to investigate whether a vasodilator and antiplatelet agent, 1,4-bis[3-(3,4,5-trimethoxybenzoyloxy) propyl]perhydro-1,4-diazepine dihydrochloride monohydrate (dilazep, DZ), has an ET-1-inhibiting effect in vitro. Bovine aortic endothelial cells (BAEC) and human umbilical vein endothelial cells (HUVEC) pretreated with fetal calf serum were treated with DZ and preproET-1 (PpET-1) transcription was evaluated by Northern blot analysis. ET-1 peptide release in culture medium was evaluated by radioimmunoassay. The effect of DZ on the ET-1 promoter/enhancer apparatus was evaluated in transfection experiments using -5 kb ET-1 promoter/enhancer constructs. Modest inhibition of PpET-1 gene transcription was detected after 30 min of DZ treatment (0.56+/-0.19 vs. 1 , p<0.01) and more marked inhibition was seen at 24 h (0.04+/-0.04 vs. 1, p<0.0001). ET-1 peptide release was suppressed strongly after 3 h (382.5+/-2.9 vs. 673.5+/-74.5pg/ml, p< 0.001) and 24 h (38.8+/-9.8 vs. 5,075+/-52.0pg/ml, p<0.0001). DZ potently inhibited PpET-1 transcription in a concentration-dependent manner (0.42+/-0.18 vs. 1, p<0.001, at 100micromol/l). DZ suppressed PpET-1 transcription in confluent HUVEC at 3 h (0.41 +/-0.11 vs. 1, p<0.0001). DZ strongly inhibited PpET-1 transcription after 1 h of thrombin (TH) treatment (0.30+/-0.01 vs. 1.51+/-0.03, p<0.0001). Transfection experiments using the 5 kb ET-1 promoter-luciferase plasmid revealed that DZ strongly suppressed ET-1 promoter activity by 99% (p<0.01). DZ potently inhibited ET-1 gene expression at the transcription level in serum- or TH-treated endothelial cells.

Plasma endothelin-1 levels and clinical correlates in patients with chronic heart failure

BACKGROUND

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide, and patients with chronic heart failure (CHF) are reported to have high plasma ET-1 levels. The aim of this study was to investigate the relation between plasma ET-1 levels and clinical correlates in patients with CHF. The effects of maximal exercise on plasma ET-1 levels were also investigated.

METHODS

Plasma concentrations of ET-1, norepinephrine, and atrial and brain natriuretic peptide (ANP and BNP) both at rest and after maximal cardiopulmonary exercise test were determined in 100 patients with CHF (60 +/- 12 years, New York Heart Association [NYHA] class I-III, left ventricular ejection fraction [LVEF]=36 +/- 8%, peak oxygen uptake [VO2] = 18.2 +/- 5.0 mL/min/kg) and 27 controls.

RESULTS

Patients with NYHA class II and III CHF had higher ET-1 levels (controls, NYHA class I, II, III: 2.1 +/- 0.6, 2.1 +/- 1.0, 2.6 +/- 0.9, 3.4 +/- 0.8 pg/mL, analysis of variance P <.0001). Maximal exercise did not alter ET-1 levels in controls or in each CHF subgroup. When all CHF patients were analyzed together, cardiothoracic ratio (P<.01), peak VO2 (P<.001), plasma norepinephrine (P<.01), plasma ANP (P<.01), and plasma BNP (P<.001) were significantly related with resting ET-1 levels on univariate analysis. Multivariate analysis revealed peak VO2 and plasma BNP levels showed an independent and significant relationship with the resting plasma ET-1 levels.

CONCLUSIONS

Resting ET-1 levels were increased in symptomatic patients with CHF, and maximal exercise did not increase ET-1 levels. Peak VO2 and plasma BNP levels were independently associated with resting plasma ET-1 levels in patients with CHF.

Increased endothelin-1 expression in the kidney in hypercalcemic rats

BACKGROUND

Although hypercalcemia causes diuresis and natriuresis, the molecular mechanisms of these effects are not well established. Recently, the important role of the calcium-sensing receptor (CaR) in hypercalcemia-induced polyuria was reported. Endothelin-1 (ET-1) that is locally produced in the nephron has been suggested to have the natriuretic and/or diuretic effects in the kidney. Therefore, we hypothesized that ET-1 expression could be increased through the activation of CaR in the kidney in hypercalcemia.

METHODS

Rats were made hypercalcemic by dihydrotachysterol (DHT) treatment. The urinary concentration of ET-1 and the mRNA expression of ET-1 in the kidney were determined. Immunohistochemistry was performed to determine types of the cells that produce ET-1. CaR and ET-1 promoter luciferase constructs were co-expressed in COS-7 cells and the ET-1 promoter activity following the addition of extracellular calcium was measured by the luciferase assay.

RESULTS

In hypercalcemic rat, urinary ET-1 excretion was increased by twofold, and ET-1 mRNA expression was increased in the kidney cortex by threefold. In cortical collecting duct (CCD), both principal cells and intercalated cells synthesized ET-1. In cells that express CaR, ET-1 promoter was activated in a dose-dependent manner by extracellular calcium over the range of 0.5 to 3.0 mmol/L.

CONCLUSIONS

First, activation of CaR increases ET-1 transcription in a dose-dependent manner. Second, hypercalcemia increases ET-1 production in the kidney cortex. These data suggest the possibility that CaR might play an important role in hypercalcemia-induced increase in ET-1 production.

Plasma endothelin-1 concentrations in children with cirrhosis and their relationship to renal function and the severity of portal hypertension

BACKGROUND

Plasma endothelin-1 (ET-1) is a potent vasoconstrictor peptide involved in the pathogenesis of several disorders. Endothelin-1 concentrations are increased in adult patients with cirrhosis. However, little is known about ET-1 concentrations in children with cirrhosis.

METHODS

Radioimmune assay was used to measure plasma ET-1 concentrations in 19 children with cirrhosis (8 patients with ascites, and 11 without ascites), and 11 age- and sex-matched healthy children. The plasma ET-1 concentrations were correlated with the mean blood pressure, creatinine clearance, and severity of portal hypertension, as measured by portal flow volume and portal flow velocity.

RESULTS

Patients with cirrhosis and ascites had increased plasma ET-1 concentrations compared with patients who did not have ascites (6.8 pg/mL +/- 0.62 pg/mL vs. 4.6 pg/mL +/- 0.35 pg/mL; mean +/- SEM; < 0.01) and controls (3.6 pg/mL +/- 0.27 pg/mL; mean +/- SEM; < 0.0005). Plasma ET-1 concentrations were higher in patients with cirrhosis who did not have ascites compared with controls ( < 0.005). No significant differences were observed between concentrations of the patients with cholestasis and those without cholestasis (5.4 pg/mL +/- 0.52 pg/mL vs. 5.2 +/- 0.32 pg/mL; mean +/- SEM; = 0.1). Plasma ET-1 concentrations correlated positively with the mean blood pressure ( = 0.58; < 0.05) and negatively with renal function, as measured by creatinine clearance ( = -0.7; <0.005). However, no correlation was detected between ET-1 concentrations and portal flow volume ( = -0.02; = 0.4) or portal flow velocity ( = -0.16; = 0.4).

CONCLUSIONS

Plasma ET-1 concentrations are increased in children with cirrhosis, with or without ascites, compared with controls. Patients with cirrhosis and ascites have increased ET-1 concentrations compared with those without ascites. The degree of increase does not relate to the severity of portal hypertension. This increase tends to maintain systemic blood pressure but is associated with a decrease in renal function.

Management of portal hypertension after variceal hemorrhage

Each variceal bleed is associated with 20% to 30% risk of dying. Management of portal hypertension after a bleed consists of (1) control of bleeding and (2) prevention of rebleeding. Effective control of bleeding can be achieved either pharmacologically by administering somatostatin or octreotide or endoscopically via sclerotherapy or variceal band ligation. In practice, both pharmacologic and endoscopic therapy are used concomitantly. Rebleeding can be prevented by endoscopic obliteration of varices. In this setting, variceal ligation is the preferred endoscopic modality. B-blockade is as effective as endoscopic therapy and, in combination, the two modalities may be additive.

Esophageal varices. I. Clinical presentation, medical therapy, and endoscopic therapy

The last half century has witnessed great advances in the understanding of the pathogenesis and natural history of portal hypertension in cirrhotics. Several pharmacologic and endoscopic techniques have been developed for the treatment of portal hypertension. The use of these agents in a given patient must be based on an understanding of the stage in the natural history of the disease and the relative efficacy and safety of the available treatment options.

Vagus nerve is involved in lack of blood reflow into sinusoids after rat hepatic ischemia

Although recovery of microcirculation is an important determinant for ischemia-reperfusion injury, little information is available about hepatic blood flow after ischemia. To examine regulatory mechanisms of postischemic hepatic microcirculation, we studied the sinusoidal blood flow after portal triad clamping of rat livers for 5, 15, or 30 min. Hepatic tissue blood flow and erythrocyte blood flow in sinusoids were measured using a laser-Doppler flowmeter and an intravital microspectroscope, respectively. There was a time of no blood flow (lag time) in sinusoids after declamping, dependent on the ischemic time. Cholinergic blockade agents eliminated the lag time, whereas nerve stimulation at the hiatus esophagus or on the hepatoduodenal ligament during reperfusion prolonged it. Chemical denervation with 10% phenol or surgical denervation on the hepatoduodenal ligament eliminated the lag time. The prolongation of lag time by nerve stimulation was completely abrogated by truncal vagotomy. These results suggest that the cholinergic vagus nerve is involved in causing the lag time of sinusoidal blood flow in hepatic ischemia-reperfusion.

Endothelin A-receptor blockade worsens endotoxin-induced hepatic microcirculatory changes and necrosis

BACKGROUND & AIMS

Endothelin 1 is considered to be an important regulator of sinusoidal blood flow and increases during endotoxemia. The purpose of this study was to investigate the role of endothelin 1 in hepatic microcirculation, oxygen transport, and liver injury during endotoxemia.

METHODS

Male Sprague-Dawley rats were continuously infused with 2.5 mL/h of saline, 0.8 mg . kg-1 . h-1 of lipopolysaccharide (LPS), 3 mg . kg-1 . h-1 of BQ-485, an endothelin A-receptor antagonist, or LPS plus BQ-485 for 7 hours.

RESULTS

BQ-485 infusion had no significant effect on hepatic microcirculation and liver injury. LPS increased the plasma levels of aspartate aminotransferase (AST) and total bilirubin and decreased the hepatic adenosine triphosphate (ATP) level and bile flow rate. LPS + BQ-485 infusion further increased the plasma levels of AST and total bilirubin and decreased the bile flow rate and the hepatic ATP level. Dual-spot microspectroscopy revealed mild decreases in sinusoidal erythrocyte velocity and oxygen transport in the LPS group and profound decreases in these parameters in the LPS + BQ-485 group. Histological examinations revealed massive necrotic changes in the pericentral regions of the LPS + BQ-485 group.

CONCLUSIONS

These results suggest that blockade of endothelin A receptors disturbs hepatic microcirculation and oxygen transport and aggravates the necrotic injury induced by endotoxin.

New concepts in the pathogenesis of portal hypertension: hepatic wounding and stellate cell contractility

The pathogenesis of portal hypertension is multifactorial, and appears to result from interplay between fixed and dynamically modulable elements; the stellate cell is a newly recognized example of the latter. This perisinusoidal, pericyte-like cell has contractile features that are most prominent after liver injury, concomitant with their activation. These data imply an exaggerated contractile phenotype in the cirrhotic liver. This cell may contribute to increased intrahepatic portal hypertension via perisinusoidal constriction of the sinusoid or by contraction of fibrous extracellular matrix rich in type I collagen with concomitant disruption of lobular architecture. Endothelins and NO play a major role in the modulation of stellate cell contractility, and are therefore important in the pathogenesis of intrahepatic portal hypertension. These new data provide potential areas for therapeutic intervention in this clinical entity.

Endothelins in chronic liver disease

This review describes recent progress in the accumulation of knowledge about the endothelins (ETs), a family of vasoactive 21-amino acid polypeptides, in chronic liver disease. Particular prominence is given to the dynamics of ET-1 and ET-3 and their possible relation to the disturbed circulation and neurohumoral dysregulation found in cirrhosis. Recent studies have shown that the ET system is highly activated in most cirrhotic patients. Circulating ET-1 and ET-3 levels have a positive relation to the severity of the disease and fluid retention, with the highest values recorded in patients with functional renal failure. Studies on liver biopsies have revealed synthesis of ET-1 in hepatic endothelial and other cells, and recent investigations have identified the hepatosplanchnic system as a major source of ET-1 and ET-3 spillover into the circulation, with a direct relation to portal venous hypertension. In addition, marked associations with disturbance of systemic haemodynamics and with abnormal distribution of blood volume have been reported. Although the pathophysiological importance of the ET system in chronic liver disease is not completely understood, similarities to other vasopressive and antinatriuretic regulatory systems (i.e. the sympathetic nervous system, renin-angiotensin-aldosterone and vasopressin) are apparent, with respect to kinetics and haemodynamic dysregulation. Cirrhosis seems to be a pathophysiological condition with indications of the occurrence of ETs, not only as local modulators, but also as a system with potential importance for systemic regulation.