Insights into Endothelin-3 and Multiple Sclerosis.

Endothelins are powerful vasoconstrictor peptides that play numerous other roles. Endothelin-1 (ET1) is the principal isoform produced by the endothelium in the human cardiovascular system. Endothelin-3 (ET3) and its rPptor affinity have been demonstrated to support neuronal repair mechanisms throughout life. In multiple sclerosis (MS), the role of vasoactive peptides are not well defined. Here we focus on ET3, specifically the plasma levels between MS patients and healthy subjects. Furthermore, we evaluated the changes in ET1 and ET3 plasma levels during different disease phases, the correlation between ET3 and cerebral circulation time, and the relationship between ET1 and ET3. In MS patients, the ET3 plasma levels were altered in a time-dependent manner. These results could support a putative role of ET3 in neuroprotection and/or neuroimmune modulation over time.

The ratio of circulating endothelin-1 to endothelin-3 associated with TIMI risk and dynamic TIMI risk score in ST elevation acute myocardial infarction.

In ST segment elevation acute myocardial infarction (STEMI), the endothelin (ET) system imbalance, reflected by the circulating ET-1:ET-3 ratio has not been investigated. This study's primary objective was to measure the circulating ET-1:ET-3 ratio and correlate it with the risk stratification for 1 year mortality of STEMI based on TIMI score. On admission, the TIMI risk score and at discharge, the dynamic TIMI risk score were calculated in 68 consecutive subjects with STEMI. Subjects with high TIMI risk score were associated with higher mean ET-1 level and ET-1:ET-3 ratio. The ET-1:ET-3 ratio more accurately predicted the high on admission TIMI risk score than the ET-1 level. Subjects with high dynamic TIMI risk score were associated with higher mean ET-1 level and ET-1:ET-3 ratio. The ET-1:ET-3 ratio more accurately predicted the high at discharge dynamic TIMI risk score than ET-1 level. From multivariable analysis, the ET-1:ET-3 ratio was not independently associated with high on admission TIMI risk score but independently predicted high at discharge dynamic TIMI risk score (odds ratio = 9.186, p = 0.018). In conclusion, combining the ET-1 and ET-3 levels into the ET-1:ET-3 ratio provided a prognostic value by independently predicting the increased risk to 1 year mortality as indicated by at discharge dynamic TIMI risk score in patients with STEMI.

Increased plasma levels of big-endothelin-2 and big-endothelin-3 in patients with end-stage renal disease.

AIMS: Big endothelins (pro-endothelin; inactive-precursor) are converted to biologically active endothelins (ETs). Mammals and humans produce three ET family members: ET-1, ET-2 and ET-3, from three different genes. Although ET-1 is produced by vascular endothelial cells, these cells do not produce ET-3, which is produced by neuronal cells and organs such as the thyroid, salivary gland and the kidney. In patients with end-stage renal disease, abnormal vascular endothelial cell function and elevated plasma ET-1 and big ET-1 levels have been reported. It is unknown whether big ET-2 and big ET-3 plasma levels are altered in these patients. The purpose of the present study was to determine whether endogenous ET-1, ET-2, and ET-3 systems including big ETs are altered in patients with end-stage renal disease. MAIN METHODS: We measured plasma levels of ET-1, ET-3 and big ET-1, big ET-2, and big ET-3 in patients on chronic hemodialysis (n=23) and age-matched healthy subjects (n=17). KEY FINDINGS: In patients on hemodialysis, plasma levels (measured just before hemodialysis) of both ET-1 and ET-3 and big ET-1, big ET-2, and big ET-3 were markedly elevated, and the increase was higher for big ETs (Big ET-1, 4-fold; big ET-2, 6-fold; big ET-3: 5-fold) than for ETs (ET-1, 1.7-fold; ET-3, 2-fold). SIGNIFICANCE: In hemodialysis patients, plasma levels of the inactive precursors big ET-1, big ET-2, and big ET-3 levels are markedly increased, yet there is only a moderate increase in plasma levels of the active products, ET-1 and ET-3. This suggests that the activity of endothelin converting enzyme contributing to circulating levels of ET-1 and ET-3 may be decreased in patients on chronic hemodialysis.

Portopulmonary hypertension and serum endothelin levels in hospitalized patients with cirrhosis.

BACKGROUND: Cirrhosis is associated with several extrahepatic manifestations including portopulmonary hypertension (PPHT). Recent data suggest that endothelins (ETs) are related to the pathophysiology of PPHT. The study aimed to measure serum ET levels in hospitalized cirrhotic patients and to determine their association with PPHT and patient outcome. METHODS: Fifty-seven cirrhotic patients [43 males; median age 58 (28-87) years] underwent Doppler echocardiography. Patients with systolic pulmonary arterial pressure ≥40 mmHg and pulmonary acceleration time <100 ms were deemed to have PPHT. ET-1, 2, and 3 serum levels were measured with an ELISA assay. All-cause mortality was recorded over a median period of 24 months. RESULTS: Nine out of 57 patients (15.8%) had PPHT. Among various clinical variables, only autoimmune hepatitis was associated with PPHT (OR=11.5; 95% CI, 1.58-83.4; P=0.01). ET-1 levels [9.1 (1.6-20.7) vs 2.5 (1.4-9.2) pg/mL, P=0.02] and the ET-1/ET-3 ratio [4.73 (0.9-22.4) vs 1.6 (0.3-10.7), P=0.02] were significantly higher in patients with PPHT than in those without. ET-2 and ET-3 levels did not differ between the two groups. There was no difference in survival between the two groups, although ET-1 levels were associated with an adverse outcome in Cox regression analysis (HR=1.11; 95% CI, 1.02-1.22; P=0.02 per unit increase in ET-1). CONCLUSION: Our data suggest that ET-1 and the ET-1/ET-3 ratio are elevated in patients with PPHT and that ET-1 is associated with a poor outcome irrespective of PPHT.

Serum adipocytokine and vascular inflammation marker levels in Beta-thalassaemia major patients.

BACKGROUND/AIM: The adipocytokines leptin and adiponectin represent a critical link between metabolism, immunity and chronic inflammation. A chronic vascular inflammatory state plays an important role in the pathophysiology of thalassaemia. We aimed to analyze the levels of these adipocytokines and determine any possible correlations with disease severity or vascular inflammation markers in beta-thalassaemia. METHODS: Serum leptin, adiponectin, high-sensitivity C-reactive protein, endothelins, vascular adhesion molecule-1, intracellular adhesion molecule-1 and L- and E-selectin were measured in 28 beta-thalassaemia patients and compared with levels in healthy controls. RESULTS: Leptin was significantly lower in patients compared to controls (2.23 ± 1.8 vs. 10.24 ± 5.78 µg/l; p = 0.0018), whereas adiponectin was elevated (11.75 ± 5.67 vs. 6.83 ± 2.75 µg/l; p = 0.009). For both adipocytokines, no correlations were found with characteristics such as age, gender, type of chelation, body mass index z score or haemoglobin. Leptin, but not adiponectin, was negatively correlated with ferritin (p = 0.032, r = -0.61). No correlations were found between leptin and the inflammation markers. However, adiponectin was positively correlated with endothelin-1 (p = 0.022, r = 0.63). CONCLUSIONS: Serum leptin is low in beta-thalassaemia, perhaps due to the toxic effect of iron overload on adipose tissue. Paradoxically, adiponectin levels are high and positively correlated with endothelin-1, raising questions about the pro- or anti-inflammatory role of this adipocytokine in beta-thalassaemia.

Endothelin-1 is not predictive of ventricular ectopy or ventricular fibrillation during acute myocardial ischemia.

Endothelin(ET)-1 (ET-1) increases after myocardial infarction and may have effects on myocardial function. ET-1 has also been shown to affect the action potential (AP) which may be arrhythmogenic and predispose to ventricular fibrillation (VF). The effects of ET-2 and ET-3 are uncertain. We hypothesized that the ETs increase during acute ischemia and that plasma levels are predictive of ischemically induced VF. Thirty-four domestic swine underwent balloon occlusion of the proximal LAD coronary artery. Occlusion was confirmed angiographically. Venous samples were collected from the right atrium at baseline and at 5 min intervals for 30 min or until VF induction. ET-1, ET-2, and ET-3 were measured using ELISA. Changes in plasma concentrations were assessed using repeated measures ANOVA with Dunnett's. A p < 0.05 was considered statistically significant. All animals had angiographic evidence of successful proximal LAD occlusion. ET-1 levels were significantly increased from a baseline at 20 min and remained elevated during 30 min of occlusion. ET-2 and ET-3 levels did not change from baseline values (figure, mean +/- SE). VF occurred in 60% of animals. Peak ET-1 values were not significantly different between VF and non-VF animals (6.2 +/- 2.2 vs. 4.8 +/- 2.3 pg/mL). No single ET-1 value had a VF predictive value >50%. There is a significant increase in ET-1 level within 20 min of acute myocardial ischemia. Despite known effects of ET-1 on the AP, this increase did not correlate with the occurrence of VF.

Q-T interval (QT(C)) in patients with cirrhosis: relation to vasoactive peptides and heart rate.

OBJECTIVE: Prolonged Q-T interval (QT) has been reported in patients with cirrhosis who also exhibit profound abnormalities in vasoactive peptides and often present with elevated heart rate (HR). The aim of this study was to relate QT to the circulating level of endothelins (ET-1 and ET-3) and calcitonin gene-related peptide (CGRP) in patients with cirrhosis. In addition, we studied problems with HR correction of QT. MATERIAL AND METHODS: Forty-eight patients with cirrhosis and portal hypertension were studied during a haemodynamic investigation. Circulating levels of ETs and CGRP were determined by radioimmunoassays. Correction of QT for HR above 60 beats per min was performed using the methods described by Bazett (QT(C)) and Fridericia (QT(F)). RESULTS: Prolonged QT(C) (above 440 ms), found in 56% of the patients, was related to the presence of significant portal hypertension and liver dysfunction (p < 0.05 to 0.001), but not to elevated ET-1, ET-3 or CGRP. When corrected according to Bazett, QT(C) showed no significant relation to differences in HR between patients (r = 0.07, ns). QTF showed some undercorrection of HR (r = -0.36; p < 0.02). During HR variation in the individual patient, QT(C) revealed a small but significant overcorrection (2.6 ms per heartbeat per min; p < 0.001). This value was significantly (p < 0.02) smaller with QTF (1.2 ms per heartbeat per min). CONCLUSIONS: The prolonged QT(C) in cirrhosis is related to liver dysfunction and the presence of portal hypertension, but not to the elevated powerful vasoconstrictor (ET-1) or vasodilator (CGRP, ET-3) peptides. The problems with correction of the QT for elevated HR in cirrhosis are complex, and the lowest HR should be applied for determination of the QT.

Endothelin-3 and PRL levels in the maternal and fetal circulation at delivery.

OBJECTIVE: The aim of the present cross-sectional study was to test the hypothesis that endothelin-3 (ET-3) is involved in PRL secretion via systemic hormonal interaction during labor. MATERIALS AND METHODS: Fifty healthy pregnant women with singleton pregnancies were included in the present study. At delivery, blood samples were drawn from umbilical vein and artery. At the same time, a blood sample was obtained from a peripheral vein of the mother. In all blood samples, plasma ET-3 and serum PRL concentrations were determined. The main outcome measures were the differences between maternal peripheral blood, umbilical artery and vein in terms of ET-3 and PRL levels, and the associations between ET-3 and PRL levels. RESULTS: ET-3 values (mean+/-SEM) in umbilical artery did not differ significantly from those in umbilical vein (4.94+/-0.27 vs 5.05+/-0.32 pg/ml) but were in both vessels significantly higher than in maternal vein (1.14+/-0.56 pg/ml, p<0.001). Serum PRL values showed similar patterns. There was a significant positive correlation of the ET-3 levels between umbilical artery and vein (r=0.906, p<0.001), but not between maternal peripheral venous blood and the umbilical vessels. Similar correlations were found for PRL values. However, no significant correlations were found between ET-3 and PRL levels in all vessels studied. CONCLUSIONS: The present study demonstrates for the first time that ET-3 levels are higher in fetal than in maternal circulation at term. The lack of correlation between ET-3 and PRL levels suggests that ET-3 does not play an important endocrine role in the control of maternal and fetal PRL secretion during labor.

Endothelin-1/endothelin-3 ratio: a potential prognostic factor of pulmonary arterial hypertension.

BACKGROUND: Pulmonary arterial hypertension (PAH) is a rare condition characterized by elevated pulmonary artery pressure leading to right-heart failure and death. Endothelin (ET)-1 has been shown to play a significant pathogenic role in PAH. ET-3 has not yet been investigated in PAH. METHODS: ET-1 and ET-3 plasma concentrations were measured in 33 PAH patients prior to any specific PAH therapy and in 9 control subjects. In PAH patients, hemodynamic parameters measured by right-heart catheterization, 6-min walk distance (6MWD), New York Heart Association (NYHA) functional class, and time until lung transplantation or death were recorded. RESULTS: In patients with PAH, levels of ET-1 were increased while those of ET-3 were decreased, as compared to control subjects (p < 0.005 for both comparisons). ET-1/ET-3 ratio varied little in control subjects, while it increased threefold in PAH patients (p < 0.0001). ET-1 correlated positively with right atrial pressure (RAP), indexed total pulmonary resistance, and negatively with cardiac index and venous saturation of oxygen (Svo(2)). ET-3 correlated positively with 6MWD. ET-1/ET-3 ratio correlated positively with RAP, negatively with Svo(2) and 6MWD, and was also associated with NYHA functional class. ET-1/ET-3 ratio was associated with prognosis in this sample of PAH patients treated with specific therapies. CONCLUSIONS: PAH is characterized by elevated ET-1 and ET-1/ET-3 ratio and decreased ET-3 plasma concentrations. All of them correlate with hemodynamic and clinical markers of disease severity. ET-1/ET-3 ratio might be a novel prognostic factor in PAH. These preliminary data should be validated in a large prospective multicenter cohort of PAH patients.

Ursodeoxycholic acid reduces increased circulating endothelin 2 in primary biliary cirrhosis.

BACKGROUND: Endothelins and nitric oxide regulate sinusoidal blood flow and the perfusion of the peribiliary vascular plexus. AIMS: To study the serum and hepatic vein concentration of ET-1, ET-2, ET-3 and nitric oxide in patients with primary biliary cirrhosis and the effect of ursodeoxycholic acid treatment. METHODS: Endothelins and nitrites/nitrates were measured in serum and hepatic vein blood in primary biliary cirrhosis and viral cirrhotic patients prior and after ursodeoxycholic acid therapy and in serum in controls. Endothelins were measured with commercial enzyme-linked immunosorbent assays and nitrites/nitrates with a modification of Griess reaction. RESULTS: The ET-1 and ET-3 levels were similar in patients and controls. Primary biliary cirrhosis patients had the highest serum ET-2 (P < 0.001) compared with other groups. Nitrites/nitrates was increased in primary biliary cirrhosis (P < 0.05) compared with normal. ET-2 and nitric oxide were similar in all primary biliary cirrhosis stages. Ursodeoxycholic acid significantly decreased ET-2 in all stages (I and II: P < 0.05 and III and IV: P < 0.01) and increased nitric oxide (P < 0.05) in early primary biliary cirrhosis. Hepatic vein ET-1 and ET-3 were higher in viral cirrhosis patients, but only in primary biliary cirrhosis a significant difference for ET-1 and ET-3 between hepatic and peripheral veins was found. CONCLUSIONS: Increased ET-2 is an early defect in primary biliary cirrhosis that is significantly reduced by the ursodeoxycholic acid treatment. The possibility of a more generalized endothelial cell dysfunction in primary biliary cirrhosis requires further investigation.

Treatment of beta-thalassemia patients with recombinant human erythropoietin: effect on transfusion requirements and soluble adhesion molecules.

The most common single genetic disorder and a major public health issue in Greece and other Mediterranean countries is beta-thalassemia. Current therapeutic approaches for homozygous beta-thalassemia entail blood transfusions and iron chelation therapy with deferoxamine or deferiprone for preventing tissue hemosiderosis. Recently, much effort has focused on various inducers of fetal hemoglobin (HbF) such as recombinant human erythropoietin (rHuEPO), especially in beta-thalassemia intermedia. Ten adult patients, 5 with beta-thalassemia major and 5 with beta-thalassemia intermedia, received 150 IU/kg rHuEPO (epoetin-alpha) subcutaneously three times a week. Seven patients were transfused every 14-30 days and 3 with beta-thalassemia intermedia were only occasionally transfused. The minimum duration of treatment was 12 weeks in order to define if there was any response. Transfusion intervals were modified according to the rHuEPO response to maintain stable Hb values. Lower transfusion requirements were observed in 5 patients after rHuEPO treatment (p = 0.028). In the 3 non-transfused patients, Hb values increased, and the patients are still being treated and followed up for a period ranging from 14 weeks to 2 years. Two patients with thalassemia major discontinued treatment after 12 weeks, as they did not achieve any response regarding transfusion requirements or Hb values. Pretreatment serum transferrin receptor levels were higher than in controls (p < 0.001) and significantly increased following rHuEPO treatment (p = 0.027). Patients had higher serum endothelin-3, sICAM-1 and sE-selectin values before rHuEPO treatment compared to controls (p < 0.001, p < 0.001 and p = 0.016, respectively), but these values were not altered during treatment. HbF values presented a slight, non-significant increase. rHuEPO treatment has a beneficial effect in transfusion-dependent beta-thalassemia patients. Although a slight increase in HbF levels was observed, other possible mechanisms are probably involved. None of our patients experienced thrombotic complications and a rise in blood pressure.

Circulating endothelin-3 levels in patients with sickle cell disease during hydroxyurea treatment.

Abnormal adhesion of red blood cells to the endothelium and the production of cytokines and vasoactive substances, such as endothelin-1 contribute to the pathogenesis of microvascular occlusion in sickle cell disease (SCD), even during the steady state. Endothelin-3 (ET-3) is a vasoconstrictive agent, which has not yet been studied in SCD.

High-frequency oscillatory ventilation does not decrease endothelin release in lung-lavaged rabbits.

UNLABELLED: High-frequency oscillatory ventilation (HFO) has been shown to reduce lung injury and pulmonary arterial pressure (PAP). We hypothesized that HFO leads to decreased endothelin 1 (ET-1) and endothelin 3 (ET-3) release when compared to conventional mechanical ventilation (CMV) in lung-lavaged rabbits. DESIGN: Prospective, randomized, controlled animal study. In 26 adult New Zealand White Rabbits ventilated by CMV or HFO under hypoxemic and normoxemic conditions after lung lavage (CMV-hypo: n = 5; CMV-normo: n = 8; HFO-hypo: n = 7; HFO-normo: n = 6) we recorded systemic and PAP, measured blood gases, ET-1 and ET-3 and calculated intrapulmonary venous admixture during a 4-h experiment. ET-1 was significantly increased after lavage (p < 0.05) with no further increase until the end of the experiment. Neither pulmonary arterial nor systemic arterial ET-1 differed between CMV and HFO or between hypoxemia and normoxemia. Systemic arterial ET-3, however, was significantly higher in HFO-hypo than in the other two groups ventilated under normoxemic conditions at the end of the experiment (HFO-hypo vs. CMV-normo, p < 0.05; HFO-hypo vs. HFO-normo, p < 0.05). PAP showed a continuous increase in all groups (p < 0.05). We did not find any correlation between PAP and ET-1 or ET-3. Intrapulmonary venous admixture increased in animals ventilated under hypoxemic conditions, whereas it decreased after lung lavage in those ventilated under normoxemic conditions until the end of the experiment (HFO-normo, p < 0.05). CONCLUSIONS: This study suggests that HFO does not decrease ET-1 and ET-3 release compared to CMV in lung-lavaged rabbits. Hypoxemia, however, may increase ET-3 release from the lungs, leading to an increased intrapulmonary shunt.

ET(B) receptor blockade potentiates the pressor response to big endothelin-1 but not big endothelin-2 in the anesthetized rabbit.

The precursor of endothelin-1, big endothelin-1, is considered to be a more reliable marker of systemic production of vasoactive peptide. However, it is largely unclear whether ET(B) receptor-dependent clearance and endothelium-derived relaxing factors affect the precursor in a similar manner to mature ET-1. These ET(B)-dependent modulations of big ET-1 and big ET-2 pressor properties were therefore studied in the anesthetized rabbit. When injected into the left cardiac ventricle, ET-1 and ET-2 (0.01 to 1 nmol/kg) each induced biphasic responses (a depressor followed by a pressor response), whereas big ET-1 and big ET-2 (0.1 to 3 nmol/kg) caused only protracted pressor responses. The highest dose of big ET-1 caused significantly greater responses than ET-1, ET-2, or big ET-2. A selective ET(A) receptor antagonist, BQ-123 (1 mg/kg), markedly reduced pressor responses to all 4 peptides, whereas blockade of ET(B) receptors with BQ-788 (0.25 mg/kg) sharply potentiated the responses to ET-1, ET-2, and big ET-1, but not to big ET-2. Indomethacin (10 mg/kg) sharply potentiated the pressor response to ET-1 (1 nmol/kg), but not big ET-1, at all time points. In control animals, ET-1, but not big ET-1, also triggered an indomethacin-sensitive increase in circulating prostacyclin. Finally, systemically administered big ET-1, but not big ET-2, induced a phosphoramidon-sensitive increase in plasma IR-ET. Our results suggest a significant limiting role of ET(B) receptors on pressor responses to big ET-1. In contrast, the same receptor entities do not modulate the hemodynamic properties of the ET-2 precursor, given that, unlike big ET-1, it is poorly converted in the pulmonary or systemic circulation in anesthetized rabbits.

Critical factors in the radioimmunoassay of endothelin-1, endothelin-3, and big endothelin-1 in human plasma.

The possible diagnostic or prognostic significance of changes in circulating level of endothelins in a variety of pathological conditions is currently of interest. Unfortunately, no consensus regarding optimization of sensitivity and extraction procedures for the reliable radioimmunoassay of endothelin-1 (ET-1), big endothelin-1 (BigET-1), and endothelin-3 (ET-3) currently exists. The object of the present study was to evaluate aspects of currently used extraction and assay procedures that limit accurate determination of ET in human plasma and define criteria to reduce variability. Critical parameters include the selectivity of commercial antibodies and the ability to remove interfering material after Sep-Pak absorption by selective washing with 24% ethanol in 4% acetic acid or methylene chloride in 0.1% trifluoroacetic acid. Assay sensitivity and specificity in the physiological range is improved by optimizing total binding parameters for the antibodies to give approximately 15-20% binding of radiolabeled peptide. With these modifications normal plasma values for ET-1, BigET-1, and ET-3 averaged 1.7 +/- 0.06, 2.5 +/- 0.3, and 5.8 +/- 0.2 pg/ml, respectively. These data suggest that such modifications may help to resolve many of the earlier difficulties concerning the role of ET under normal and pathological conditions.

Receptor subtype mediating the action of circulating endothelin on glucose metabolism and hemodynamics in perfused rat liver.

The subtype of endothelin receptor that mediates metabolic and hemodynamic effects of circulating endothelin was explored using perfused rat liver. Infusion of endothelin (ET)-1 or ET-3 into the portal vein at a concentration of 0.3 nM increased glucose and lactate output and decreased perfusion flow, although ET-3 was less effective than ET-1. The metabolic effects of ET-1 were observed even under costant-flow perfusion. Infusion of either sarafotoxin S6b or S6c, an ET(A)- or ET(B)-receptor agonist, mimicked the actions of ET-1 to an equal extent. The flow reduction and glucose production induced by ET-1 were partly attenuated by the ET(A)-receptor antagonist BQ485. By contrast, ET(B)-receptor antagonist BQ788 enhanced glucose production caused by ET-1 and ET-3 without affecting the hemodynamic change. The effects of ET-1 and ET-3 were almost totally inhibited by the combination of BQ485 and BQ788. These results suggest that both ET(A) and ET(B) receptors are involved in the metabolic and hemodynamic effects of circulating endothelin in rat liver, while the ET(A)-receptor-mediated action appears to be dominant.

Hepatic blood flow and splanchnic oxygen consumption in patients with liver failure. Effect of high-volume plasmapheresis.

Liver failure represents a major therapeutic challenge, and yet basic pathophysiological questions about hepatic perfusion and oxygenation in this condition have been poorly investigated. In this study, hepatic blood flow (HBF) and splanchnic oxygen delivery (DO2, sp) and oxygen consumption (VO2,sp) were assessed in patients with liver failure defined as hepatic encephalopathy grade II or more. Measurements were repeated after high-volume plasmapheresis (HVP) with exchange of 8 to 10 L of plasma. HBF was estimated by use of constant infusion of D-sorbitol and calculated according to Fick's principle from peripheral artery and hepatic vein concentrations. In 14 patients with acute liver failure (ALF), HBF (1.78 +/- 0.78 L/min) and VO2,sp (3.9 +/- 0.9 mmol/min) were higher than in 11 patients without liver disease (1.07 +/- 0.19 L/min, P <.01) and (2.3 +/- 0.7 mmol/min, P <.001). In 9 patients with acute on chronic liver disease (AOCLD), HBF (1.96 +/- 1.19 L/min) and VO2,sp (3.9 +/- 2.3 mmol/min) were higher than in 18 patients with stable cirrhosis (1.00 +/- 0.36 L/min, P <.005; and 2.0 +/- 0.6 mmol/min, P <.005). During HVP, HBF increased from 1.67 +/- 0.72 to 2.07 +/- 1.11 L/min (n=11) in ALF, and from 1.89 +/- 1.32 to 2.34 +/- 1.54 L/min (n=7) in AOCLD, P <.05 in both cases. In patients with ALF, cardiac output (thermodilution) was unchanged (6.7 +/- 2.5 vs. 6.6 +/- 2.2 L/min, NS) during HVP. Blood flow was redirected to the liver as the systemic vascular resistance index increased (1,587 +/- 650 vs. 2, 020 +/- 806 Dyne. s. cm-5. m2, P <.01) whereas splanchnic vascular resistance was unchanged. In AOCLD, neither systemic nor splanchnic vascular resistance was affected by HVP, but as cardiac output increased from 9.1 +/- 2.8 to 10.1 +/- 2.9 L/min (P <.01) more blood was directed to the splanchnic region. In all liver failure patients treated with HVP (n=18), DO2,sp increased by 15% (P <.05) whereas VO2,sp was unchanged. Endothelin-1 (ET-1) and ET-3 were determined before and after HVP. Changes of ET-1 were positively correlated with changes in HBF (P <.005) and VO2,sp (P <.05), indicating a role for ET-1 in splanchnic circulation and oxygenation. ET-3 was negatively correlated with systemic vascular resistance index before HVP (P <.05) but changes during HVP did not correlate. Our data suggest that liver failure is associated with increased HBF and VO2, sp. HVP further increased HBF and DO2,sp but VO2,sp was unchanged, indicating that splanchnic hypoxia was not present.

Endothelin-1 and endothelin-3 levels in different types of glomerulonephritis.

There is evidence that an activated renal endothelin (ET) system is involved in development of glomerulosclerosis. However it is still unknown if different ETs are involved in the pathogenesis of various types of glomerulonephritis (GN). This study characterized ET-1 and ET-3 levels in patients suffering from chronic GN. We performed a prospective study to evaluate the ET-1 and ET-3 levels in 19 patients with biopsy-proven GN, including four minimal-change nephropathies (MCN), six perimembraneous GN (PM-GN), and nine mesangioproliferative GN (MP-GN). Twelve healthy subjects matched for age and sex served as controls. ET-1 and ET-3 were measured in plasma (p) and in urine [spontaneous urine (sp.urine) and urine over 24 h (24-h urine)] using a specific radioimmunoassay. Patients and controls were compared using the Wilcoxon rank-sum test. In MCN, ET-1 levels were enhanced in sp. urine (p = 0.03) and 24-h urine (p = 0.01), whereas ET-3 levels did not differ from controls. In comparison, in PM-GN we found an increased ET-3 level in 24-h urine (p = 0.004). In MP-GN, ET-3 levels were also elevated in p (p = 0.0002) and urine specimens (sp. urine p = 0.05; 24-h urine p = 0.03). No positive correlation to C3 or C4 complement fractions was found. Age, blood pressure or renal function did not correlate with ET-1 or ET-3 levels. In MP-GN and PM-GN, ET-3 is elevated whereas ET-1 is not. In contrast ET-1 is increased in MC-GN. These data indicate an important role for the ET-1 and ET-3 systems in the pathophysiology of different forms of GN. This is significant with regard to an early preservation of renal function at the onset of GN by the use of selective ET antagonists.

Circulating endothelin-3 and prolactin concentrations in healthy lactating women during the early puerperium.

OBJECTIVE: To study the association between the circulating concentrations of endothelin-3 and prolactin in the early puerperium. DESIGN: Prospective clinical study, including twenty-five healthy puerperal women breast-feeding their healthy full-term infants. METHODS: Venous blood was drawn on day 1 and 4 post partum, and plasma endothelin-3 and serum prolactin were determined. RESULTS: Circulating endothelin-3 and prolactin levels on day 4 did not differ significantly from the corresponding levels on day 1. However, a significant negative correlation was found on day 4 between endothelin-3 and prolactin values (r = -0.688, P < 0.001) and an even stronger negative association existed between the net change in endothelin-3 from days 1 to 4 and the corresponding change in prolactin values (r = -0.732, P < 0.001). CONCLUSIONS: On the fourth day post partum, lactating healthy women show negative correlation between circulating endothelin-3 and prolactin levels. Whether this indicates a role for endothelin-3 in the control of prolactin secretion in the post partum period remains to be clarified.