[Genetic polymorphisms and liver diseases].
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Amino Acid Substitution↗
Biomedical subjects
R Bataller
Publications and source records attributed to R Bataller.
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.
Ascites↗
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.
Adrenomedullin↗
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.
Benzimidazoles↗
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.
Animals↗
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.
Chronic Disease↗
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.
Adult↗
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.
Journal Article↗
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.
Angiotensin II↗
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.
Adult↗
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.
Aged↗
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.
Ascites↗
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.
Diagnosis, Differential↗
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.
Animals↗
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.
Acute Disease↗
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.
Animals↗
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.
Adult↗
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.
Adrenomedullin↗