The MELD Score Is Superior to the Maddrey Discriminant Function Score to Predict Short-Term Mortality in Alcohol-Associated Hepatitis: A Global Study

INTRODUCTION

Several scoring systems predict mortality in alcohol-associated hepatitis (AH), including the Maddrey discriminant function (mDF) and model for end-stage liver disease (MELD) score developed in the United States, Glasgow alcoholic hepatitis score in the United Kingdom, and age, bilirubin, international normalized ratio, and creatinine score in Spain. To date, no global studies have examined the utility of these scores, nor has the MELD-sodium been evaluated for outcome prediction in AH. In this study, we assessed the accuracy of different scores to predict short-term mortality in AH and investigated additional factors to improve mortality prediction.

METHODS

Patients admitted to hospital with a definite or probable AH were recruited by 85 tertiary centers in 11 countries and across 3 continents. Baseline demographic and laboratory variables were obtained. The primary outcome was all-cause mortality at 28 and 90 days.

RESULTS

In total, 3,101 patients were eligible for inclusion. After exclusions (n = 520), 2,581 patients were enrolled (74.4% male, median age 48 years, interquartile range 40.9-55.0 years). The median MELD score was 23.5 (interquartile range 20.5-27.8). Mortality at 28 and 90 days was 20% and 30.9%, respectively. The area under the receiver operating characteristic curve for 28-day mortality ranged from 0.776 for MELD-sodium to 0.701 for mDF, and for 90-day mortality, it ranged from 0.773 for MELD to 0.709 for mDF. The area under the receiver operating characteristic curve for mDF to predict death was significantly lower than all other scores. Age added to MELD obtained only a small improvement of AUC.

DISCUSSION

These results suggest that the mDF score should no longer be used to assess AH's prognosis. The MELD score has the best performance in predicting short-term mortality.

Using an automatic pulse voltammetric electronic tongue to verify the origin of honey from Spain, Honduras, and Mozambique

BACKGROUND

The growing need to classify the origin of honey in a simple way is leading to the development of affordable analytical equipment that is in-line and manageable, enabling rapid on-site screening. The aim of this work was therefore to evaluate whether an electronic tongue (made of four metallic electrodes: Ir, Rh, Pt, Au), based on potential multistep pulse voltammetry with electrochemical polishing, is able to differentiate between honey samples from Spain, Honduras, and Mozambique.

RESULTS

It was demonstrated, for the first time, that automatic pulse voltammetry, in combination with principal component analysis (PCA) statistical analysis, was able to differentiate honey samples from these three countries. A partial least squares (PLS) analysis predicted the level of certain physicochemical parameters, the best results being for conductivity and moisture with correlation coefficients of 0.948 and 0.879, whereas the weakest correlation was for the sugars.

CONCLUSION

The tool proposed in this study could be applied to identify the country origin of the three types of multifloral honey considered here. It also offers promising perspectives for expanding knowledge of the provenance of honey. All of this could be achieved when a comprehensive database with the information generated by this electronic tongue has been created. © 2019 Society of Chemical Industry.

SPARC (secreted protein acidic and rich in cysteine) knockdown protects mice from acute liver injury by reducing vascular endothelial cell damage

Secreted protein, acidic and rich in cysteine (SPARC) is involved in many biological process including liver fibrogenesis, but its role in acute liver damage is unknown. To examine the role of SPARC in acute liver injury, we used SPARC knock-out (SPARC(-/-)) mice. Two models of acute liver damage were used: concanavalin A (Con A) and the agonistic anti-CD95 antibody Jo2. SPARC expression levels were analyzed in liver samples from patients with acute-on-chronic alcoholic hepatitis (AH). SPARC expression is increased on acute-on-chronic AH patients. Knockdown of SPARC decreased hepatic damage in the two models of liver injury. SPARC(-/-) mice showed a marked reduction in Con A-induced necroinflammation. Infiltration by CD4+ T cells, expression of tumor necrosis factor-α and interleukin-6 and apoptosis were attenuated in SPARC(-/-) mice. Sinusoidal endothelial cell monolayer was preserved and was less activated in Con A-treated SPARC(-/-) mice. SPARC knockdown reduced Con A-induced autophagy of cultured human microvascular endothelial cells (HMEC-1). Hepatic transcriptome analysis revealed several gene networks that may have a role in the attenuated liver damaged found in Con A-treated SPARC(-/-) mice. SPARC has a significant role in the development of Con A-induced severe liver injury. These results suggest that SPARC could represent a therapeutic target in acute liver injury.

Glyphosate detection by means of a voltammetric electronic tongue and discrimination of potential interferents

A new electronic tongue to monitor the presence of glyphosate (a non-selective systemic herbicide) has been developed. It is based on pulse voltammetry and consists in an array of three working electrodes (Pt, Co and Cu) encapsulated on a methacrylate cylinder. The electrochemical response of the sensing array was characteristic of the presence of glyphosate in buffered water (phosphate buffer 0.1 mol · dm-3, pH 6.7). Rotating disc electrode (RDE) studies were carried out with Pt, Co and Cu electrodes in water at room temperature and at pH 6.7 using 0.1 mol · dm-3 of phosphate as a buffer. In the presence of glyphosate, the corrosion current of the Cu and Co electrodes increased significantly, probably due to the formation of Cu2+ or Co2+ complexes. The pulse array waveform for the voltammetric tongue was designed by taking into account some of the redox processes observed in the electrochemical studies. The PCA statistical analysis required four dimensions to explain 95% of variance. Moreover, a two-dimensional representation of the two principal components differentiated the water mixtures containing glyphosate. Furthermore, the PLS statistical analyses allowed the creation of a model to correlate the electrochemical response of the electrodes with glyphosate concentrations, even in the presence of potential interferents such as humic acids and Ca2+. The system offers a PLS prediction model for glyphosate detection with values of 098, -2.3 × 10-5 and 0.94 for the slope, the intercept and the regression coefficient, respectively, which is in agreement with the good fit between the predicted and measured concentrations. The results suggest the feasibility of this system to help develop electronic tongues for glyphosate detection.

Human myofibroblastic hepatic stellate cells express Ca(2+)-activated K(+) channels that modulate the effects of endothelin-1 and nitric oxide

BACKGROUND/AIMS

High-conductance Ca(2+)-activated K(+) (BK(Ca)) channels modulate the effects of vasoactive factors in contractile cells. It is unknown whether hepatic stellate cells (HSCs) contain BK(Ca) channels and what their role in the regulation of HSCs contractility is.

METHODS

The presence of BK(Ca) channels in HSCs was assessed by the patch-clamp technique. The functional role of BK(Ca) channels was investigated by measuring intracellular calcium concentration ([Ca(2+)](i)) and cell contraction in individual cells after stimulation with endothelin-1 in the presence or absence of specific modulators of BK(Ca) channels.

RESULTS

BK(Ca) channels were detected by patch-clamp in most of the activated HSCs studied. Incubation of cells with iberiotoxin, a BK(Ca) channel blocker, increased both the sustained phase of [Ca(2+)](i) elicited by endothelin-1 and the number of cells undergoing contraction, while the use of NS1619, a BK(Ca) channel opener, induced opposite effects. Stimulation of HSCs with S-nitroso-N-acetyl-penicillamine (SNAP), a nitric oxide (NO)-donor, increased the opening of BK(Ca) channels and reduced the effects of endothelin-1. Conversely, iberiotoxin abolished the inhibitory effect of SNAP on endothelin-induced [Ca(2+)](i) increase and cell contraction.

CONCLUSIONS

Activated human HSCs contain BK(Ca) channels that modulate the contractile effect of endothelin-1 and mediate the inhibitory action of NO.

Hepatic stellate cells as a target for the treatment of liver fibrosis

Following chronic liver injury of any etiology, there is progressive fibrosis. To date, removing the causative agent is the only effective therapy to stop or even reverse liver fibrosis. Therefore, the development of effective antifibrotic therapies represents a challenge for modern hepatology. In the past decade, dramatic advances have been made in the understanding of the cellular and molecular mechanisms underlying liver fibrogenesis. The identification of activated hepatic stellate cells (HSCs) as the major fibrogenic cell type in the injured liver, as well as the recognition of key cytokines involved in this process, have facilitated the design of promising new antifibrotic therapies. These therapies are aimed at inhibiting the accumulation of activated HSCs at the sites of liver injury and preventing the deposition of extracellular matrix. Although many of these approaches are effective in experimental models of liver fibrosis, their efficacy and safety in humans are still unknown. This review describes the current therapeutic approaches for liver fibrosis and discusses different features of activated HSCs as a target to design new treatments to inhibit scar formation in chronic liver diseases.

In vitro and in vivo activation of rat hepatic stellate cells results in de novo expression of L-type voltage-operated calcium channels

Following chronic liver injury, hepatic stellate cells (HSCs) transdifferentiate into myofibroblast-like cells, which develop contractile properties and contribute to increased resistance to blood flow. We investigated whether this phenotypic activation includes changes in the expression of L-type voltage-operated Ca2+ channels (VOCC), which mediate Ca2+ influx and regulate cell contraction in vascular cell types. Rat HSCs were studied in the quiescent phenotype and after their activation in vitro (cultured on plastic for 14 days) and in vivo (isolated from rats with CCl(4)-induced cirrhosis). Patch-clamp studies showed Ca2+ currents through L-type VOCC in HSCs activated both in vitro and in vivo, whereas no currents were detected in quiescent HSCs. Moreover, binding studies with (3)H-isradipine, a specific L-type VOCC antagonist, showed a large number of binding sites in activated HSCs, while no specific binding was found in quiescent HSCs. Finally, messenger RNA (mRNA) encoding L-type VOCC was not detected in quiescent HSCs as assessed by reverse transcription-polymerase chain reaction (RT-PCR) and Northern blot analysis, whereas it was present in activated HSCs. Stimulation of L-type VOCC with KCl resulted in a marked increase in [Ca2+](i) followed by cell contraction in HSCs activated both in vitro and in vivo, whereas no effects were observed in quiescent HSCs. We conclude that the activation of HSCs is associated with up-regulation of L-type VOCC that mediate Ca2+ influx and cell contraction. These results may be relevant to the pathogenesis of portal hypertension.

Increased circulating leptin levels in chronic alcoholism

BACKGROUND

Malnutrition seen in chronic alcoholics is partly due to reduced energy intake. Leptin is a peptide hormone implicated in the regulation of appetite and expenditure of energy. The prevalence and significance of abnormal circulating leptin levels in alcoholics, as well as the relationship of these levels with nutritional status, liver disease, and ethanol consumption, remain uncertain.

METHODS

Serum leptin levels were measured in 60 active asymptomatic alcoholics, 20 active alcoholics with cirrhosis of the liver, 20 abstinent alcoholics, and 60 controls. Nutritional status and ethanol consumption also were assessed.

RESULTS

In the control group, circulating leptin levels (mean 4.7+/-0.3 microg/liter) correlated with body fat stores. Despite showing a lower fat area of the arm, active alcoholics had significantly higher leptin levels than the controls (p < 0.001), regardless of the presence of cirrhosis. By contrast, none of the abstinent alcoholics showed hyperleptinemia. In the multivariate regression analysis, the fat area of the arm (p < 0.001), the lifetime ethanol consumption (p = 0.007), and the number of cigarettes smoked per day (p = 0.02) were found to be independent factors that influenced leptin levels in active alcoholics. After we adjusted for age, fat area of the arm, and tobacco consumption, a significant correlation was observed between lifetime consumption of ethanol and serum leptin concentrations (r = 0.36, p < 0.001).

CONCLUSIONS

Circulating leptin levels are increased in a dose-dependent manner in chronic alcoholism, regardless of nutritional status or the presence of compensated liver disease.

Human hepatic stellate cells secrete adrenomedullin: potential autocrine factor in the regulation of cell contractility

BACKGROUND/AIMS

Hepatic stellate cells (HSCs) are perisinusoidal pericytes which have receptors for vasoactive factors, such as endothelin-1, which can regulate cell contractility in an autocrine manner. It is unknown whether human HSCs have receptors for and are able to synthesize the vasodilator peptide adrenomedullin (ADM), a peptide produced by most contractile cells.

METHODS AND RESULTS

Stimulation of HSCs with ADM resulted in a dose-dependent raise in cAMP concentration (radioimmunoassay) and markedly blunted the endothelin-induced increase in [Ca2+]i and cell contraction, as assessed in cells loaded with fura-2 using a morphometric method. The existence of the receptor CRLR for ADM and their associated proteins RAMP-1 and RAMP-2 was demonstrated by reverse transcriptase-polymerase chain reaction (RT-PCR). Moreover, activated human HSCs spontaneously secreted ADM in the culture medium in a time-dependent manner. ADM secretion was markedly enhanced by tumour necrosis factor-alpha and interleukin-1beta. Specific mRNA for ADM (RT-PCR and Northern blot) was detected in HSCs and increased after incubation of cells with cytokines.

CONCLUSIONS

Human HSCs have functional receptors for ADM, the stimulation of which blunts the contractile effect of endothelin-1. Cultured human HSCs secrete ADM in baseline conditions. This secretion is markedly increased by cytokines. These results suggest that ADM can regulate HSCs' contractility in an autocrine manner.

A prognostic model for predicting survival in cirrhosis with ascites

BACKGROUND/AIMS

Parameters evaluating renal function and systemic hemodynamics are of prognostic significance in cirrhosis with ascites but are rarely used in the evaluation of survival of these patients. The aim of the current study was to develop a prognostic model to estimate survival of patients with cirrhosis and ascites.

METHODS

216 Cirrhotic patients admitted to hospital for the treatment of ascites were evaluated. Thirty-two demographic, clinical and laboratory variables, including parameters assessing liver and renal function and systemic hemodynamics, were analyzed as predictive factors of survival by using a Cox regression model.

RESULTS

Four variables had independent prognostic value: renal water excretion, as assessed by measuring diuresis after water load, mean arterial pressure, Child-Pugh class, and serum creatinine. According to these features a prognostic index was calculated that allows to estimate survival in patients with cirrhosis and ascites. The model accurately predicted survival in an independent series of 84 patients with cirrhosis and ascites.

CONCLUSION

A prognostic model that uses four easily available variables and predicts prognosis in cirrhotic patients with ascites has been developed. This model may be useful in the evaluation of patients with ascites for liver transplantation.

Hepatorenal Syndrome

The management of the hepatorenal syndrome (HRS) constitutes a major challenge for clinicians. Because HRS is a functional disorder due to advanced liver disease and is associated with a very low survival expectancy, orthotopic liver transplantation (OLT) is the only effective and permanent treatment for patients with HRS. However, OLT is not applicable to all cirrhotic patients despite the presence of HRS. In addition, because of the poor prognosis of HRS and the prolonged waiting lists in most transplant centers a significant proportion of these patients may die before OLT is possible. Therefore, there is a need for effective therapies for HRS that improve renal function and increase survival. Such treatments are of interest not only as a bridge to OLT but also as a therapy for patients who are not candidates for transplantation. Preliminary studies have suggested that the administration of splanchnic vasoconstrictors such as terlipressin in combination with volume expanders or the insertion of transjugular intrahepatic portosystemic shunts (TIPS) may improve renal function in patients with HRS. However, before these treatments are widely recommended further studies are necessary.

Prevalence and prognostic value of hepatocellular carcinoma in cirrhotic patients presenting with spontaneous bacterial peritonitis

BACKGROUND/AIMS

This study examined the prognostic power of hepatocellular carcinoma in patients presenting an episode of spontaneous bacterial peritonitis treated with 3rd generation cephalosporins or quinolones, and subsequent prophylaxis with norfloxacin until death or transplantation.

METHODS

The study comprises the prospective evaluation of 168 consecutive cirrhosis patients presenting an episode of spontaneous bacterial peritonitis.

RESULTS

Hepatocellular carcinoma was diagnosed in 35 out of the 168 (20%) patients included in the study (10 single; 25 advanced tumors). Renal impairment developed in 82 patients. Resolution of infection was achieved in 90% of the cases, the hospital survival being 70%. Renal impairment, advanced tumor stage, albumin, and GGT showed independent prognostic value for hospital mortality. At the end of follow-up 101 patients had died, the 1- and 2-year survival being 36% and 31%, respectively. Four variables independently predicted survival: advanced tumor (OR: 3.9; p=0.00001), renal impairment (OR: 2.1; p=0.00001), bilirubin (OR: 1.6; p=0.02) and creatinine (OR: 1.3; p=0.03). Advanced tumor retained independent predictability in patients surviving hospitalization (OR: 7.5; p=0.0001), the 6-month survival being significantly lower in patients with advanced tumor (12% vs 57%, p<0.00001).

CONCLUSION

The prevalence of hepatocellular carcinoma in cirrhotic patients with spontaneous bacterial peritonitis is high, and its presence should be actively sought. Advanced tumor impairs both hospital and long-term survival, and should be considered in the design of future trials.

Hepatocyte-derived cysteinyl leukotrienes modulate vascular tone in experimental cirrhosis

BACKGROUND & AIMS

The leukotrienes C(4)/D(4)/E(4) (cysteinyl-LTs) are 5-lipoxygenase (5-LO)-derived eicosanoids with potent vasoconstrictor, proliferative, and profibrogenic properties that may participate in key pathophysiologic events in liver cirrhosis. We examined the cysteinyl-LT biosynthetic pathway in liver tissue and purified liver cells isolated from rats with carbon tetrachloride-induced cirrhosis, and assessed the vasoactive properties of LTD(4) in hepatic stellate cells (HSCs) and anesthetized rats.

METHODS & RESULTS

Liver homogenates from cirrhotic rats had increased 5-LO mRNA and cysteinyl-LT content, as determined by Northern blot and enzyme immunoassay, respectively. In isolated rat liver cells, 5-LO mRNA expression was found to be restricted to Kupffer cells. However, among the liver cells (i.e., hepatocytes, Kupffer cells, HSCs, and sinusoidal endothelial cells), hepatocytes exhibited the highest ability to generate cysteinyl-LTs from the unstable intermediate LTA(4). Hepatocytes from cirrhotic rats showed an enhanced baseline generation of cysteinyl-LTs, but their ability to synthesize cysteinyl-LTs from exogenous LTA(4) was found to be similar to that of hepatocytes from normal animals. Both LTD(4) and hepatocyte-conditioned medium increased intracellular Ca(2+) concentration and induced contraction in HSCs, suggesting that hepatocyte-derived cysteinyl-LTs could act in a paracrine fashion on nearby nonparenchymal liver cells. The relevance of these in vitro findings was further established in vivo by the observation that LTD(4) significantly increased portal pressure in anesthetized rats.

CONCLUSIONS

These data suggest a role for hepatocyte-derived cysteinyl-LTs in mediating hepatic vascular tone abnormalities in cirrhosis.

Terlipressin plus albumin infusion: an effective and safe therapy of hepatorenal syndrome

BACKGROUND/AIM

Ornipressin, a vasopressin analog with potent splanchnic vasoconstrictor action, has been shown to reverse hepatorenal syndrome. However, its usefulness in clinical practice is limited by frequent ischemic complications. The aim of this study was to assess the efficacy of terlipressin, an analog of vasopressin with a low profile of side effects, plus albumin in this condition.

METHODS

Nine consecutive patients with cirrhosis and hepatorenal syndrome were included in a pilot study of terlipressin (0.5-2 mg/4 h i.v.) therapy associated with iv albumin.

RESULTS

Treatment (9 days, range 5-15) was associated with a marked reduction of serum creatinine (3.9+/-0.7 to 1.3+/-0.1 mg/dl, p<0.001, mean+/-SE). Reversal of hepatorenal syndrome (reduction of creatinine below 1.5 mg/dl) was observed in seven of the nine patients. There was a remarkable improvement in circulatory function, with an increase in mean arterial pressure (68+/-2 to 80+/-4 mmHg, p<0.05) and suppression of vasoconstrictor systems activity (plasma renin activity and plasma norepinephrine decreased from 23+/-12 ng/ml x h and 1549+/-373 pg/ml to 3.5+/-2 ng/ml x h and 373+/-98 pg/ml, respectively, p<0.01 for both). No patient developed signs of intestinal, myocardial or distal ischemia.

CONCLUSIONS

Terlipressin associated with albumin appears to be a safe and effective treatment of hepatorenal syndrome.

Angiotensin II induces contraction and proliferation of human hepatic stellate cells

BACKGROUND & AIMS

Circulating levels of angiotensin II (ANGII), a powerful vasoconstrictor factor, are frequently increased in chronic liver diseases. In these conditions, hepatic stellate cells (HSCs) proliferate and acquire contractile properties. This study investigated the presence of receptors for ANGII and the effects of ANGII in human HSCs activated in culture.

METHODS

The presence of ANGII receptors was assessed by binding studies. The effects of ANGII on intracellular calcium concentration ([Ca(2+)](i)), cell contraction, and cell proliferation were also assessed.

RESULTS

Binding studies showed the presence of ANGII receptors of the AT1 subtype. ANGII elicited a marked dose-dependent increase in [Ca(2+)](i) and cell contraction. Moreover, ANGII stimulated DNA synthesis and increased cell number. All these effects were totally blocked by losartan and reduced by nitric oxide donors or prostaglandin E(2). The effects of ANGII were barely detectable in quiescent cells (2 days in culture), suggesting that phenotypic transformation of HSCs is associated with a marked increase in the effects of ANGII.

CONCLUSIONS

ANGII induces contraction and is mitogenic for human-activated HSCs by acting through AT1 receptors. These results suggest that activated HSCs are targets of the vasoconstrictor action of ANGII in the intrahepatic circulation.

Hepatorenal syndrome

Hepatorenal syndrome is a functional renal failure that occurs in cirrhotic patients with advanced liver disease and ascites. The diagnostic criteria and clinical types of this syndrome have recently been revised. Hepatorenal syndrome is caused by marked hypoperfusion of the kidney as the result of renal vasoconstriction, which is thought to be the extreme manifestation of an underfilling of the arterial circulation. This circulatory dysfunction is the consequence of arterial vasodilation in the splanchnic circulation. Liver transplantation is the best treatment for HRS, but its applicability is low because of the short survival of these patients. New therapies, such as the use of systemic vasoconstrictors or TIPS, seem promising, but prospective investigations are needed to delineate their role in the management of cirrhotic patients with HRS.

Mechanisms of ascites formation

Ascites is the most common complication of cirrhosis. It is associated with profound changes in the splanchnic and systemic circulation and with renal abnormalities. The development of ascites is related to the existence of severe sinusoidal portal hypertension that causes marked splanchnic arterial vasodilation and a forward increase in the splanchnic production of lymph. Splanchnic arterial vasodilation also produces arterial vascular underfilling, arterial hypotension, compensatory activation of the RAAS, SNS, and AVP, and a continuous sodium and water retention, leading to ascites formation. Now, therefore, the splanchnic arterial circulation, rather than the venous portal system, is believed to be involved in the pathogenesis of ascites formation.

Prolonged cholestasis after acute paraquat poisoning through skin absorption

Ingestion of paraquat is the most common cause of fatal pesticide poisoning. Liver involvement in acute paraquat poisoning is self-limited and usually consists of cholestasis. However, long-term hepatic effects after paraquat exposition have not been described up to now, probably because of the high mortality rate of this acute poisoning. We report the case of an agricultural worker who developed persistent cholestasis after an episode of acute paraquat poisoning through skin absorption.

Atrial natriuretic peptide antagonizes endothelin-induced calcium increase and cell contraction in cultured human hepatic stellate cells

Hepatic stellate cells (HSCs) participate in the regulation of hepatic microcirculation and have receptors for many vasoconstrictor factors. It is unknown whether HSCs have receptors for circulating vasodilators such as atrial natriuretic peptide (ANP). This study investigated the presence of ANP receptors in human HSCs and whether ANP antagonizes the effects of endothelin-1 in these cells. ANP receptors were assessed by binding and cross-linking studies, reverse-transcriptase polymerase chain reaction (PCR), and measuring intracellular cyclic guanosine monophosphate concentration. Intracellular calcium concentration ([Ca(2+)](i)) and cell contraction were measured in individual cells loaded with fura-2 using a morphometric method. Binding and cross-linking affinity experiments showed the existence of ANP receptors in human HSCs. PCR products with the expected length were obtained for guanylate cyclase A receptor, the physiological receptor of ANP, both in quiescent and activated human cells. ANP induced a dose-dependent increase in intracellular cyclic guanosine monophosphate concentration and blunted the increase in [Ca(2+)](i) elicited by endothelin-1. Most importantly, ANP markedly reduced cell contraction induced by endothelin-1. HSCs isolated from rats with carbon tetrachloride-induced cirrhosis showed a higher number of ANP receptors compared with HSCs isolated from normal rats, indicating that in vivo activation of HSCs is associated with an up-regulation of ANP receptors. These results indicate that human HSCs have receptors for ANP, the activation of which reduces the effects of endothelin-1 on [Ca(2+)](i) and cell contraction. ANP could participate in regulating the contractility of HSCs by antagonizing the effect of vasoconstrictors.

Contraction of human hepatic stellate cells activated in culture: a role for voltage-operated calcium channels

BACKGROUND/AIMS

Voltage-operated calcium channels are essential for the regulation of vascular tone and are potential targets for vasodilating agents. They regulate calcium entry and thereby cell contraction in vascular cell types. Hepatic stellate cells in the activated phenotype have contractile properties and could participate in the regulation of sinusoidal blood flow. Thus, this study was aimed at investigating the presence of voltage-operated calcium channels in human hepatic stellate cells activated in culture and the effects of their stimulation on intracellular calcium concentration ([Ca2+]i) and cell contractility.

METHODS

Binding studies using [3H]-nitrendipine were performed to demonstrate the presence of voltage-operated calcium channels. Voltage-operated calcium channels were stimulated by causing cell membrane depolarization either by electrical field stimulation or extracellular high potassium. [Ca2+]i and cell contraction were measured in individual cells loaded with fura-2 using a morphometric method with an epifluorescence microscope coupled to a charge-coupled device-imaging system.

RESULTS

Binding studies demonstrated the existence of voltage-operated calcium channels in human activated hepatic stellate cells (7.1+/-1.4x10(4) sites/cell with a Kd of 2.1+/-0.1 nM). Both electrical field stimulation and potassium chloride-induced cell depolarization resulted in a marked and prolonged increase in [Ca2+]i followed by intense cell contraction. The degree of cell contraction correlated with the intensity of calcium peaks. Removal of extracellular calcium or preincubation of cells with nitrendipine, a specific antagonist of voltage-operated calcium channels, completely blocked the effects on [Ca2+]i and cell contraction, whereas preincubation of cells with BayK-8644, a specific agonist of voltage-operated calcium channels, increased calcium peaks and contraction.

CONCLUSION

Activated human hepatic stellate cells have a large number of voltage-operated calcium channels, the activation of which is associated with an increase in [Ca2+]i followed by marked cell contraction. Voltage-operated calcium channels probably play an important role in the regulation of activated hepatic stellate cells contractility.

Increased cerebrovascular resistance in cirrhotic patients with ascites

Studies assessing regional hemodynamics in patients with cirrhosis and ascites have shown vasodilation in the splanchnic circulation and vasoconstriction in the renal circulation and in the brachial and femoral artery vascular territories. The aim of this study was to assess the cerebral vascular resistance in cirrhotic patients with ascites. The resistive index in the middle cerebral artery (an index of the cerebral vascular resistance) and in a renal interlobar artery were measured by Doppler ultrasonography in 7 healthy subjects: 13 patients with compensated cirrhosis and 24 patients with ascites (13 with renal failure). The arterial blood pressure and the activity of the renin-angiotensin and sympathetic nervous systems, as estimated by plasma renin activity and plasma norepinephrine concentration, respectively, were also measured. The resistive index in the middle cerebral artery was significantly increased in patients with ascites (0.68 +/- 0.05, mean +/- SD) as compared with patients without ascites (0.60 +/- 0.01, P < .05) and with healthy patients (0.52 +/- 0.01, P < .01). Renal resistive index was also increased in patients with ascites (0.77 +/- 0.01) compared with the other two groups (0.68 +/- 0.02 and 0.62 +/- 0.00, respectively; P < .001). The resistive index in the middle cerebral artery showed a direct correlation with renal resistive index (r = .73, P < .01), plasma renin activity (r = .61, P < .01), and norepinephrine (r = .53, P < .01). The resistive index in the middle cerebral artery showed an inverse correlation with mean arterial pressure (r = -.45, P < .01). These results indicate that in patients with cirrhosis and ascites there is a cerebral vasoconstriction which is probably related with the arterial hypotension and the overactivity of vasoconstrictor systems.

Increased adrenomedullin levels in cirrhosis: relationship with hemodynamic abnormalities and vasoconstrictor systems

BACKGROUND & AIMS

Arterial vasodilation in cirrhosis may be related to increased circulating levels of vasodilators. This study was designed to assess the circulating levels of adrenomedullin, a recently described vasodilator peptide, in cirrhosis.

METHODS

Plasma adrenomedullin levels were measured in 17 healthy subjects and 34 cirrhotic patients. Hemodynamic parameters, renal function, and levels of vasoactive substances were also assessed.

RESULTS

Patients with ascites had increased adrenomedullin levels (289 +/- 47 pg/mL) compared with healthy subjects and patients without ascites (135 +/- 17 and 142 +/- 32 pg/mL, respectively; P < 0.05). Adrenomedullin levels correlated inversely with arterial pressure, glomerular filtration rate, and renal plasma flow and correlated directly with pulse rate, endothelin levels, and aldosterone and plasma renin activity. In cirrhotic patients, no significant differences in adrenomedullin levels were found between samples obtained from hepatic vein, renal vein, pulmonary artery, and femoral artery. Plasma expansion with albumin suppressed the renin-angiotensin system but did not affect adrenomedullin levels.

CONCLUSIONS

Circulating levels of adrenomedullin are increased in patients with ascites and correlate with hemodynamic and renal abnormalities and activation of vasoconstrictor systems. These increased levels seem to result from a generalized increase in adrenomedullin production from vascular tissue and are not suppressed by plasma expansion. Adrenomedullin may participate in the pathogenesis of arterial vasodilation in cirrhosis.

Esophageal variceal bleeding caused by hypoplasia of the portal vein in a patient with the Klippel-Trenaunay syndrome

The case of a patient affected by Klippel-Trenaunay syndrome presenting with esophageal variceal bleeding caused by hypoplasia of the vena porta is reported. Hemostasis was achieved by performing a proximal spleno-renal shunt. We discuss the likely association of this mesodermal development abnormality and vascular disorders of the portal vein.

Hepatorenal syndrome

The hepatorenal syndrome is a severe and common complication of patients with advanced cirrhosis and ascites. It is characterised not only by renal failure but also by marked alterations in systemic haemodynamics. Renal failure is due to a marked hypoperfusion of the kidney secondary to renal vasoconstriction. Although the pathogenesis of hepatorenal syndrome is not completely understood, it is thought to be the extreme manifestation of the underfilling of the arterial circulation secondary to an arterial vasodilation, located mainly in the splanchnic circulation. Recently, a revised definition and diagnostic criteria of hepatorenal syndrome have been proposed. The prognosis of patients with hepatorenal syndrome is very poor. Liver transplantation is the only effective treatment but it is not applicable in most cases due to short survival. New therapies developed during the last years, such as the use of systemic vasoconstrictors or transjugular intra-hepatic portosystemic shunts appear to be promising, but prospective investigations are needed to delineate their real usefulness.

Management of ascites in cirrhosis

Ascites is one of the earliest and most common complications of patients with cirrhosis. A typical circulatory dysfunction characterized by arterial vasodilation, high cardiac output and stimulation of vasoactive systems is commonly present in these patients and is associated with a poor prognosis. The treatment of ascites has been based on the combination of a low-sodium diet and the administration of diuretics. The reintroduction of paracentesis and the recent introduction of the transjugular intrahepatic portosystemic shunt (TIPS) are the most relevant innovations in the treatment of ascites during the past two decades, although controlled trials in large series of patients are needed to delineate whether TIPS is a safe and useful treatment for these patients.

Hepatorenal syndrome

Hepatorenal syndrome is a common complication in patients with advanced cirrhosis and ascites characterized not only by renal failure but also by marked alterations in systemic hemodynamics and vasoactive systems. Renal failure is due to a marked hypoperfusion of the kidney secondary to renal vasoconstriction. The pathogenesis of hepatorenal syndrome is not completely known but it is thought to be the extreme manifestation of the underfilling of the arterial circulation secondary to an arterial vasodilation, located mainly in the splanchnic circulation. Recently, a new definition and diagnostic criteria of hepatorenal syndrome have been proposed, which has stimulated research in this field. Prognosis of patients with hepatorenal syndrome is very poor. Liver transplantation is the only effective treatment but it is not applicable in all patients due to short survival. New therapies developed during the last few years, such as the use of systemic vasoconstrictors or transjugular intrahepatic portosystemic shunts appear promising, but their usefulness should be evaluated in prospective investigations.

Effect of therapeutic paracentesis on plasma volume and transvascular escape rate of albumin in patients with cirrhosis

BACKGROUND/AIMS

Circulatory abnormalities with activation of vasoconstrictor systems after large-volume paracentesis are generally considered secondary to an increased extravasation of fluid from the intravascular compartment to the extravascular space with subsequent reduction in plasma volume. To test this hypothesis, plasma volume, the transvascular escape rate of albumin, the absolute escape rate of albumin and the activity of vasoconstrictor systems were measured in 25 cirrhotic patients with ascites in baseline conditions and 2 days after total paracentesis with plasma volume expansion.

METHODS

Plasma volume and the transvascular escape rate of albumin, the fraction of albumin passing from the intravascular to the extravascular space per unit of time, were assessed through the plasma disappearance curve of radioiodinated human albumin. The absolute escape rate of albumin, the total flux of albumin from intravascular to extravascular space per unit of time, was also calculated.

RESULTS

Eight of the 25 patients (32%) developed marked activation of vasoconstrictor systems after paracentesis. In these patients, plasma renin activity and plasma norepinephrine concentration increased from 6.6+/-2 to 23.4+/-11 ng x ml(-1) x h(-1) and 776+/-229 to 989+/-258 pg/ml, respectively (p<0.05). No significant changes in these parameters were found in the remaining 17 patients. The activation of vasoconstrictor systems occurred in the absence of changes in plasma volume (3456+/-276 vs 3476+/-264 ml, NS), transvascular escape rate of albumin (10.4+/-1 vs 10.9+/-2%/h, NS) and absolute escape rate of albumin (9.9+/-1.9 vs 10.5+/-0.7 g/h, NS).

CONCLUSIONS

These results do not support a contraction of plasma volume as the mechanism responsible for activation of vasoconstrictor systems after paracentesis. Rather, the activation of vasoconstrictor systems in the absence of changes in plasma volume suggests that paracentesis accentuates the impairment of "effective" blood volume present in cirrhotic patients with ascites.

Practical recommendations for the treatment of ascites and its complications

Ascites is one of the earliest and most common complications of patients with cirrhosis, and is associated with complications such as dilutional hyponatraemia, renal dysfunction and spontaneous bacterial peritonitis. The treatment of ascites has been based on the combination of a low-sodium diet and the administration of diuretics. The reintroduction of paracentesis and the recent introduction of the transjugular intrahepatic portosystemic shunt (TIPS) are the most relevant innovations in the treatment of ascites during the past 2 decades. The development of ascites is closely related to renal disturbances of functional origin, including the hepatorenal syndrome. A new definition of hepatorenal syndrome has been proposed recently and 2 different types have been defined (type I or progressive, and type III or stable). Although no effective therapy exists for this syndrome, the use of therapeutic methods (TIPS, vasoconstrictor agents, dialysis) to temporarily improve renal function and act as a 'bridge' to liver transplantation, may be of most benefit. The use of potent and safe antibiotics has improved the resolution rate and survival of patients with spontaneous bacterial peritonitis. In addition, the use of oral antibiotics will simplify the management of this condition in the near future. Finally, prophylactic antibiotic regimens represent a major step forwards in the prevention of spontaneous bacterial peritonitis in subsets of cirrhotic patients with a great risk of developing this complication.

Arginine vasopressin induces contraction and stimulates growth of cultured human hepatic stellate cells

BACKGROUND & AIMS

Hepatic stellate cells (HSCs) are perisinusoidal cells believed to participate in the regulation of hepatic blood flow because of their contractile properties and presence of receptors for several vasoactive factors. It is unknown whether HSCs have receptors for vasopressin, one of the most potent endogenous vasoconstrictors. This study investigated the existence of receptors for and the effects of arginine vasopressin (AVP) on cultured human HSCs.

METHODS

intracellular calcium concentration ([Ca2+]i) and cell contraction were measured in individual cells loaded with fura-2 using a morphometric method with an epifluorescence microscope coupled to a CCD imaging system (Photometrics, Tucson, AZ). AVP-specific binding was measured with [3H]AVP. Mitogen-activated protein kinase (MAPk) activity and DNA synthesis were measured by in vitro phosphorylation of myelin basic protein and [3H]thymidine incorporation, respectively. Parallel experiments were performed in vascular smooth muscle cells.

RESULTS

AVP elicited a dose-dependent increase in [Ca2+]i and contraction of HSCs. Moreover, AVP increased MAPk activity, DNA synthesis, and cell number. These effects were similar to those observed in vascular smooth muscle cells and were blocked by a V1 receptor antagonist. The existence of V1 receptors was further confirmed by binding studies.

CONCLUSIONS

Human HSCs have V1-vasopressin receptors that induce effects similar to those observed in vascular smooth muscle cells. AVP may play a role in the regulation of HSC function.

Impairment of renal function during moderate physical exercise in cirrhotic patients with ascites: relationship with the activity of neurohormonal systems

Moderate physical exercise does not affect glomerular filtration rate (GFR) and renal excretory function in normal subjects. This study is aimed at assessing the effects of moderate physical exercise on renal function in 21 nonazotemic cirrhotic patients with ascites. Arterial pressure, heart rate, and renal function were assessed in the patients after 2 hours in the supine position and during 30 minutes of moderate cycloergometric exercise in the sitting position. The activity of the renin-aldosterone and sympathetic nervous systems and the plasma levels of antidiuretic hormone (ADH) and atrial natriuretic peptide (ANP) were determined at the end of each period. Physical exercise induced a marked reduction in GFR (75 +/- 10 to 49 +/- 6 mL/min), free-water clearance (6.1 +/- 1 to 3.4 +/- 1 mL/min), and sodium excretion (7.8 +/- 2 to 4.3 +/- 1 microEq/min) in 10 patients (Group I). In the remaining 11 cases (Group II) there were no changes in these parameters. Renal perfusion significantly decreased in both groups although the reduction was greater in Group I (-34.7% +/- 4.6% vs. -7.5% +/- 3.1%, P < .001). Physical exercise was associated with a significant and comparable increase in arterial pressure, heart rate, and plasma levels of renin, aldosterone, and norepinephrine (NE) in the two groups of patients. The ANP concentration did not change. Patients from Groups I and II differed significantly (P < .05) only in plasma renin activity (PRA) and NE concentration, which were higher in Group I patients both in the supine rest (renin: 4.7 +/- 1.6 vs. 1.4 +/- 0.5 ng/mL x h; NE: 576 +/- 115 vs. 288 +/- 42 pg/ mL) and during exercise (renin: 7.1 +/- 1.8 vs. 2.6 +/- 1 ng/ mL x h; NE: 925 +/- 135 vs. 630 +/- 90 pg/mL). In conclusion, moderate physical exercise has no detrimental effects on renal function in cirrhotic patients with ascites with no or mild activation of the renin-aldosterone and sympathetic nervous systems. However, moderate physical exercise causes a marked impairment in the renal function of patients with ascites with marked stimulation of these vasoconstrictor systems.

[Pyloric stenosis complicated by Wernicke-Korsakoff syndrome]

The Wernicke-Korsakoff syndrome (WKS) is a picture of oculomotor alterations, ataxia and confusion presented in chronic alcoholics. It has more rarely been described in non alcoholic patients with malnutrition. The case of a patient with ulcerous peptic disease of long evolution who consulted for a picture compatible with WKS following clinical manifestations of repeated vomiting secondary to complete pyloric stenosis is presented. The peculiarity of the picture and the convenience of prevention in malnourished patients receiving intravenous glucose sera is discussed.

Spontaneous bacterial peritonitis in patients with cirrhosis undergoing selective intestinal decontamination. A retrospective study of 229 spontaneous bacterial peritonitis episodes

BACKGROUND/AIMS

Selective intestinal decontamination with norfloxacin is widely used to prevent spontaneous bacterial infections in cirrhosis. The study was performed to compare the spontaneous bacterial peritonitis occurring in patients with and without prophylactic norfloxacin.

METHODS

Two hundred and twenty-nine consecutive episodes of spontaneous bacterial peritonitis, (193 in patients without (Group A) and 36 in patients with norfloxacin prophylaxis (Group B)), were retrospectively analyzed. In 100 episodes (86 and 14, respectively), the responsible organism was isolated in ascitic fluid.

RESULTS

Clinical and laboratory data at diagnosis were comparable in both groups. There were marked differences (p < 0.001) between group A and B in the frequency of peritonitis caused by gram-negative (67.4% vs. 14.3%) and gram-positive (30.2% vs. 78.6%) bacteria. There were three polymicrobial episodes. Bacteria resistant to cefotaxime and gram-negative bacilli resistant to quinolones were isolated in ascitic fluid in nine (seven in Group A and two in Group B) and three episodes (all in Group A), respectively. No differences in the course of infection and patient survival were observed between groups.

CONCLUSIONS

Spontaneous bacterial peritonitis in patients with and without prophylaxis with norfloxacin are not different in clinical features, response to treatment and prognosis. Spontaneous bacterial peritonitis caused by gram-negative organisms resistant to quinolones is extremely uncommon in patients with cirrhosis receiving prophylactic norfloxacin.

Urinary excretion of urodilatin in patients with cirrhosis

Cirrhotic patients with ascites show increased plasma levels of natriuretic peptides from cardiac origin (i.e., atrial natriuretic peptide [ANP] and brain natriuretic peptide [BNP]). Urodilatin is a unique member of the natriuretic peptide family because it is exclusively synthesized in the kidney acting on a paracrine fashion in the regulation of sodium excretion. To investigate the renal production of urodilatin in cirrhosis and its relationship with other natriuretic peptides and sodium retention, urodilatin excretion and plasma levels of ANP were measured in 21 healthy subjects, 13 cirrhotic patients without ascites and 23 cirrhotic patients with ascites. Urine urodilatin was measured with a highly specific radioimmunoassay using a polyclonal antibody against human urodilatin. Patients with ascites had marked sodium retention (UNa 7 +/- 2 mEq/d) as compared to patients without ascites and healthy subjects (29 +/- 3 mEq/d and 34 +/- 5 mEq/d, respectively, P < .001). Patients with cirrhosis and ascites had urine urodilatin excretion similar to patients without ascites and healthy subjects (82 +/- 8 pmol/g, 95 +/- 10 pmol/g, and 89 +/- 9 pmol/ g of creatinine, respectively; not significant). In addition, immunoreactive urodilatin from cirrhotic patients with ascites and healthy subjects showed a similar chromatographic pattern. By contrast, plasma ANP levels were increased significantly in patients with ascites (29 +/- 3 fmol/mL) as compared with patients without ascites or healthy subjects (14 +/- 3 fmol/mL and 6 +/- 1 fmol/mL, respectively; P < .01). In conclusion, urine urodilatin excretion is normal in patients with cirrhosis even in the presence of marked sodium retention. The coexistence of increased ANP levels and normal urodilatin excretion suggests that in cirrhosis both natriuretic peptides are regulated independently.

Renal and neurohormonal changes following simultaneous administration of systemic vasoconstrictors and dopamine or prostacyclin in cirrhotic patients with hepatorenal syndrome

BACKGROUND/AIMS

Intravenous ornipressin in cirrhotic patients with hepatorenal syndrome causes marked improvement of systemic hemodynamics and suppression of plasma renin and norepinephrine but only moderate improvement of renal function. This study was designed to investigate whether these beneficial effects could be enhanced by the simultaneous administration of dopamine. The renal effects of the i.v. infusion of norepinephrine plus prostacyclin in patients with hepatorenal syndrome were also assessed.

METHODS

Renal plasma flow, glomerular filtration rate, free water clearance, sodium excretion and the plasma levels of renin and norepinephrine were measured in baseline conditions and during the administration of ornipressin (6 i.u./h) and ornipressin (6 i.u./h) plus dopamine (2 micrograms/kg.min) in nine patients with hepatorenal syndrome. Five additional patients with hepatorenal syndrome were studied prior to and following the administration of norepinephrine (0.45 +/- 0.1 microgram/kg.min) and norepinephrine (0.85 +/- 0.2 microgram/kg.min) plus prostacyclin (5 ng/kg.min).

RESULTS

Despite a significant increase in arterial pressure and marked suppression of plasma renin activity during ornipressin and ornipressin plus dopamine administration, no significant improvement in renal function was observed. Norepinephrine and norepinephrine plus prostacyclin also failed to increase renal perfusion and glomerular filtration rate.

CONCLUSIONS

The combined administration of systemic vasoconstrictors (ornipressin or norepinephrine) and vasodilators (dopamine or prostacyclin), at the doses used in the current study and for a short period of time, does not improve renal function in cirrhotic patients with hepatorenal syndrome. The current study does not confirm a potential role for ornipressin in the treatment of hepatorenal syndrome.

[Asymptomatic pneumoperitoneum after fiber gastroscopy]

A case of asymptomatic pneumoperitoneum after fiber gastroscopic sclerosis of bleeding gastric erosions is presented. Air bubbles in gastric curvatures without evidence of macroscopic perforation were found at laparotomy. We comment the etiologies of pneumoperitoneum without macroscopic perforation and suggest that the management of patients with asymptomatic pneumoperitoneum with normal clinical examination and blood analysis might be conservative to avoid needless laparotomies.

[A functioning carcinoid tumor with liver involvement without the associated carcinoid syndrome]

The carcinoid tumor, the most frequent variety of the neuroendocrine or amine precursor uptake and decarboxylation (APUD) tumors, typically produces biogenic amines and polypeptide hormones and occasionally gives rise to a striking clinical presentation called carcinoid syndrome. The severity of this syndrome is directly related to the tumor bulk draining into the systemic circulation. This implies almost always hepatic metastases. We present a case in which a carcinoid tumor with extensive hepatic involvement and remarkable biologic activity did not produce any clinical features of the carcinoid syndrome. We believe that such a case enlightens the clinical and biochemical complexity of this entity.

Effect of upright posture and physical exercise on endogenous neurohormonal systems in cirrhotic patients with sodium retention and normal supine plasma renin, aldosterone, and norepinephrine levels

It is well known that sodium retention occurs in a significant proportion of patients with cirrhosis despite normal supine plasma levels of renin, aldosterone (ALDO), and norepinephrine (NE). The current study was performed to assess whether this subset of patients also present normal activity of the renin-aldosterone and sympathetic nervous systems during upright posture in sitting position and moderate physical exercise. Nine healthy controls, 14 patients with compensated cirrhosis and 10 patients with cirrhosis, ascites, sodium retention, and normal supine plasma renin activity (PRA) and ALDO and NE concentration were sequentially studied after 60 minutes in supine rest, 30 minutes in sitting position, and 30 minutes of cycloergometric exercise (3-METs). Sitting position and exercise were associated with similar stimulation of the renin-aldosterone and sympathetic nervous systems in the three groups of subjects. Consequently, cirrhotic patients with ascites showed values of PRA and plasma concentration of ALDO and NE similar to healthy subjects and patients with compensated cirrhosis during supine rest (renin: 1.4 +/- 0.3, 0.8 +/- 0.2, and 0.8 +/- 0.3 ng/mL; aldosterone: 24.3 +/- 4.7, 20.2 +/- 3.9 and 21.4 +/- 3.4 ng/dL; norepinephrine: 252 +/- 23, 250 +/- 16, and 255 +/- 23 pg/mL), sitting position (renin: 2.1 +/- 0.5, 1.1 +/- 0.3, and 1.6 +/- 0.4; aldosterone: 32.2 +/- 7.3, 23.7 +/- 5.3, and 26.2 +/- 4.5; norepinephrine: 356 +/- 38, 401 +/- 63, and 420 +/- 35), and exercise (renin: 2.9 +/- 0.8, 1.6 +/- 0.4, and 2.2 +/- 0.5; aldosterone: 43 +/- 6.4, 34.9 +/- 8.5, and 38.2 +/- 5.3; norepinephrine: 481 +/- 35, 499 +/- 54, and 534 +/- 48).(ABSTRACT TRUNCATED AT 250 WORDS)