Primary prophylaxis of variceal bleeding in children and the role of MesoRex Bypass: Summary of the Baveno VI Pediatric Satellite Symposium.

UNLABELLED: Approaches to the management of portal hypertension and variceal hemorrhage in pediatrics remain controversial, in large part because they are not well informed by rigorous clinical studies. Fundamental biological and clinical differences preclude automatic application of approaches used for adults to children. On April 11-12, 2015, experts in the field convened at the first Baveno Pediatric Satellite Meeting to discuss and explore current available evidence regarding indications for MesoRex bypass (MRB) in extrahepatic portal vein obstruction and the role of primary prophylaxis of variceal hemorrhage in children. Consensus was reached regarding MRB. The vast majority of children with extrahepatic portal vein obstruction will experience complications that can be prevented by successful MRB surgery. Therefore, children with extrahepatic portal vein obstruction should be offered MRB for primary and secondary prophylaxis of variceal bleeding and other complications, if appropriate surgical expertise is available, if preoperative and intraoperative evaluation demonstrates favorable anatomy, and if appropriate multidisciplinary care is available for postoperative evaluation and management of shunt thrombosis or stenosis. In contrast, consensus was not achieved regarding primary prophylaxis of varices. Although variceal hemorrhage is a concerning complication of portal hypertension in children, the first bleed appears to be only rarely fatal and the associated morbidity has not been well characterized. CONCLUSION: There are few pediatric data to indicate the efficacy and safety of pharmacologic or endoscopic therapies as primary prophylaxis or that prevention of a sentinel variceal bleed will ultimately improve survival; therefore, no recommendation for primary prophylaxis with endoscopic variceal ligation, sclerotherapy, or nonspecific beta-blockade in children was proposed.

Prevention of portal hypertension: from variceal development to clinical decompensation.

Pharmacological treatment of portal hypertension (PH) has been exclusively devoted to gastroesophageal varices-related events at different frameworks, including prophylactic, emergency, or preventive therapy. The goals of treatment are to avoid the first bleeding episode, stop active bleeding, and prevent bleeding recurrence, respectively. The objective of preprimary prophylaxis (PPP) is to avoid variceal development, and therefore it necessarily deals with patients with cirrhosis at earlier stages of the disease. At these earlier stages, nonselective beta-blockers (NSBBs) have been ineffective in preventing the development of varices and other complications of PH. Therefore, treatment should not rely on NSBB. It is possible that, at these earlier stages, etiological treatment of liver disease itself could prevent progression of PH. This review will focus mainly on early treatment of PH, because, if successful, it may translate into histological-hemodynamic improvements, avoiding not only variceal development, but also other PH-related complications, such as ascites and portosystemic encephalopathy. Moreover, the advent of new therapies may allow not only the prevention of the complications of PH, but also the chance of a substantial degree of regression in the cirrhotic process, with the possible prevention of hepatocellular carcinoma (HCC).

Portal hypertension in children: expert pediatric opinion on the report of the Baveno v Consensus Workshop on Methodology of Diagnosis and Therapy in Portal Hypertension.

Complications of portal hypertension in children lead to significant morbidity and are a leading indication for consideration of liver transplantation. Approaches to the management of sequelae of portal hypertension are well described for adults and evidence-based approaches have been summarized in numerous meta-analyses and conferences. In contrast, there is a paucity of data to guide the management of complications of portal hypertension in children. An international panel of experts was convened on April 8, 2011 at The Children's Hospital of Pittsburgh of UPMC to review and adapt the recent report of the Baveno V Consensus Workshop on the Methodology of Diagnosis and Therapy in Portal Hypertension to the care of children. The opinions of that expert panel are reported.

Quantitative histological-hemodynamic correlations in cirrhosis.

UNLABELLED: We have previously shown, in a semiquantitative analysis of liver biopsies showing cirrhosis, that thickness of fibrous septa separating cirrhotic nodules and small size of cirrhotic nodules correlated independently with portal pressure (as determined by the hepatic venous pressure gradient; HVPG) and were independent predictors of the presence of clinically significant portal hypertension (PH). This study aimed to confirm these results using quantitative analysis of these biopsies using digital image analysis. Biopsies of 42 patients with cirrhosis and HVPG measurements within 6 months of the biopsy were included in the study. The following parameters were scored quantitatively and without knowledge of HVPG results: total fibrosis area, septal thickness, nodule size, and number of nodules per millimeter of length of liver biopsy. Fibrosis area was the only parameter that independently correlated with HVPG (r = 0.606; P < 0.0001). Correlation was significant, even among patients with clinically significant PH (r = 0.636; P < 0.005). Fibrosis area and nodule size were both independently predictive of the presence of clinically significant PH (r = 0.57; P = 0.003). CONCLUSIONS: On quantitative analysis, fibrosis area was the parameter that correlated best with HVPG and the presence of clinically significant PH. Beyond pathophysiological implications, this also has methodological implications that are discussed in this article.

Intestinal and plasma VEGF levels in cirrhosis: the role of portal pressure.

Increased levels of intestinal VEGF are thought to worsen portal hypertension. The cause of the increase in the level of intestinal VEGF found during cirrhosis is not known. The aim of this study is to demonstrate a relationship between portal pressure (PP) and intestinal/ plasma VEGF levels in different stages of fibrosis/cirrhosis. In this experiment, rats were exposed to carbon tetrachloride (CCl(4) ) for 6, 8 and 12 weeks. At the end of exposure, the three groups of rats exhibited three different stages of pathology: non-cirrhotic, early fibrotic and cirrhotic, respectively. For those rats and their age-matched controls, PP and intestinal/plasma VEGF levels were measured. Rats inhaling CCl(4) for 12 weeks developed portal hypertension (18.02 ± 1.07 mmHg), while those exposed for 6 weeks (7.26 ± 0.58 mmHg) and for 8 weeks (8.55 ± 0.53 mmHg) did not. The rats exposed for 12 weeks also showed a 40% increase in the level of intestinal VEGF compared to the controls (P < 0.05), while those rats exposed to CCl(4) inhalation for 6 and 8 weeks did not. There was a significant positive correlation between PP and intestinal VEGF levels (r(2) = 0.4, P < 0.005). Plasma VEGF levels were significantly elevated in those rats exposed to 12 weeks of CCl(4) inhalation (63.7 pg/ml, P < 0.01), compared to the controls (8.5 pg/ml). However, no correlation was observed between PP and plasma VEGF levels. It is concluded that portal pressure modulates intestinal VEGF levels during the development of cirrhosis.

A distinct nitric oxide and adenosine A1 receptor dependent hepatic artery vasodilatatory response in the CCl-cirrhotic liver.

UNLABELLED: Increase of portal venous vascular resistance is counteracted by decrease of hepatic arterial vascular resistance (hepatic arterial buffer response). This process is mediated by adenosine in normal livers. In cirrhosis, hepatic arterial vascular resistance is decreased but the involvement of adenosine in this process is unknown. The aim of our study was to identify the signalling pathway responsible for the decreased hepatic arterial resistance in cirrhotic livers. METHODS: Cirrhosis was induced by CCl(4). Using a bivascular liver perfusion dose-response curves to adenosine of the HA were performed in the presence and the absence of pan-adenosine blocker (8-SPT), A1 blocker (caffeine) or nitric oxide synthase-blocker (l-NMMA) after preconstriction with an alpha1-agonist (methoxamine). Western blot of the HA were used to measure the density of the A1 and A2a receptors. RESULTS: Adenosine caused a dose dependent relaxation of the hepatic artery of both cirrhotic and control animals that were blocked in both groups by 8-SPT (P<0.02). The response to adenosine was greater in cirrhotic rats (P=0.016). Both l-NMMA (P=0.003) and caffeine reduced the response to adenosine in cirrhotic but not in control animals. Western blot analysis showed a higher density of A1 and a lower density of A2a receptor in cirrhotic animals (P<0.05). CONCLUSION: The adenosine-induced vasodilatation of the HA is increased in cirrhotic rats suggesting a role for adenosine-NO in the decreased hepatic arterial vascular resistance found in cirrhosis. This significantly greater response in cirrhosis by the A1 receptor follows the same pathway that is seen in hypoxic conditions in extra-hepatic tissues.

Incidence, prevalence, and clinical significance of abnormal hematologic indices in compensated cirrhosis.

BACKGROUND & AIMS: Patients with cirrhosis develop abnormal hematologic indices (HI) from multiple factors, including hypersplenism. We aimed to analyze the sequence of events and determine whether abnormal HI has prognostic significance. METHODS: We analyzed a database of 213 subjects with compensated cirrhosis without esophageal varices. Subjects were followed for approximately 9 years until the development of varices or variceal bleeding or completion of the study; 84 subjects developed varices. Abnormal HI was defined as anemia at baseline (hemoglobin, < or =13.5 g/dL for men and 11.5 g/dL for women), leukopenia (white blood cell counts, < or =4000/mm3), or thrombocytopenia (platelet counts, < or =150,000/mm3). The primary end points were death or transplant surgery. RESULTS: Most subjects had thrombocytopenia at baseline. Kaplan-Meier analysis showed that leukopenia occurred by 30 months (95% confidence interval, 18.5-53.6), and anemia occurred by 39.6 months (95% confidence interval, 24.1-49.9). Baseline thrombocytopenia (P = .0191) and leukopenia (P = .0383) were predictors of death or transplant, after adjusting for baseline hepatic venous pressure gradient (HVPG), and Child-Pugh scores. After a median of 5 years, a significant difference in death or transplant, mortality, and clinical decompensation was observed in patients who had leukopenia combined with thrombocytopenia at baseline compared with patients with normal HI (P < .0001). HVPG correlated with hemoglobin and white blood cell count (hemoglobin, r = -0.35, P < .0001; white blood cell count, r = -0.31, P < .0001). CONCLUSIONS: Thrombocytopenia is the most common and first abnormal HI to occur in patients with cirrhosis, followed by leukopenia and anemia. A combination of leukopenia and thrombocytopenia at baseline predicted increased morbidity and mortality.

Hepatic venous pressure gradient predicts development of hepatocellular carcinoma independently of severity of cirrhosis.

BACKGROUND/AIMS: A total of 213 patients with compensated cirrhosis, portal hypertension and no varices were included in a trial evaluating beta-blockers in preventing varices. Predictors of the development of hepatocellular carcinoma (HCC), including hepatic venous pressure gradient (HVPG) were analyzed. METHODS: Baseline laboratory tests, ultrasound and HVPG measurements were performed. Patients were followed prospectively every three months until development of varices or variceal bleeding or end of the study in 09/02. The endpoint was HCC development according to standard diagnostic criteria. Univariate and multivariate Cox regression models were developed to identify predictors of HCC. RESULTS: In a median follow-up of 58 months 26/213 (12.2%) patients developed HCC. Eight patients were transplanted and 28 patients died without HCC. Twenty-one (84%) HCC developed in patients with HCV. On multivariate analysis HVPG (HR 1.18; 95%CI 1.08-1.29), albumin (HR 0.34; 95%CI 0.14-0.83) and viral etiology (HR 4.59; 95%CI 1.51-13.92) were independent predictors of HCC development. ROC curves identified 10 mmHg of HVPG as the best cut-off; those who had an HVPG above this value had a 6-fold increase in the HCC incidence. CONCLUSIONS: Portal hypertension is an independent predictor of HCC development. An HVPG >10 mmHg is associated with a 6-fold increase of HCC risk.

Adenosine induces loss of actin stress fibers and inhibits contraction in hepatic stellate cells via Rho inhibition.

The Rho/ROCK pathway is activated in differentiated hepatic stellate cells (HSCs) and is necessary for assembly of actin stress fibers, contractility, and chemotaxis. Despite the importance of this pathway in HSC biology, physiological inhibitors of the Rho/ROCK pathway in HSCs are not known. We demonstrate that adenosine induces loss of actin stress fibers in the LX-2 cell line and primary HSCs in a manner indistinguishable from Rho/ROCK inhibition. Loss of actin stress fibers occurs via the A2a receptor at adenosine concentrations above 10 muM, which are present during tissue injury. We further demonstrate that loss of actin stress fibers is due to a cyclic adenosine monophosphate, protein kinase A-mediated pathway that results in Rho inhibition. Furthermore, a constitutively active Rho construct can inhibit the ability of adenosine to induce loss of actin stress fibers. Actin stress fibers are required for HSC contraction, and we demonstrate that adenosine inhibits endothelin-1 and lysophosphatidic acid-mediated HSC contraction. We propose that adenosine is a physiological inhibitor of the Rho pathway in HSCs with functional consequences, including loss of HSC contraction.

Vascular endothelial dysfunction in cirrhosis.

Endothelial dysfunction is regarded as an early key event in multiple diseases. The assessment of vascular nitric oxide (NO) level is an indicative of endothelial dysfunction. In liver cirrhosis, on one hand, endothelial dysfunction is known as impaired endothelium-dependent relaxation in the liver microcirculation and contributes to increased intra-hepatic vascular resistance, leading to portal hypertension. On the other, increased production of vasodilator molecules mainly NO contributes to increased endothelium-dependent relaxation in the arteries of the systemic and splanchnic circulation. The aims of this review are to summarize and discuss: (1) unique characteristics of sinusoidal endothelial cell (SECs) and SEC dysfunctions in cirrhosis, and (2) endothelial dysfunctions in the arterial splanchnic and systemic circulation in cirrhosis with portal hypertension.

Nitric oxide synthase generates nitric oxide locally to regulate compartmentalized protein S-nitrosylation and protein trafficking.

Nitric oxide (NO) is a highly diffusible and short-lived physiological messenger. Despite its diffusible nature, NO modifies thiol groups of specific cysteine residues in target proteins and alters protein function via S-nitrosylation. Although intracellular S-nitrosylation is a specific posttranslational modification, the defined localization of an NO source (nitric oxide synthase, NOS) with protein S-nitrosylation has never been directly demonstrated. Endothelial NOS (eNOS) is localized mainly on the Golgi apparatus and in plasma membrane caveolae. Here, we show by using eNOS targeted to either the Golgi or the nucleus that S-nitrosylation is concentrated at the primary site of eNOS localization. Furthermore, localization of eNOS on the Golgi enhances overall Golgi protein S-nitrosylation, the specific S-nitrosylation of N-ethylmaleimide-sensitive factor and reduces the speed of protein transport from the endoplasmic reticulum to the plasma membrane in a reversible manner. These data indicate that local NOS action generates organelle-specific protein S-nitrosylation reactions that can regulate intracellular transport processes.

Expert pediatric opinion on the Report of the Baveno IV consensus workshop on methodology of diagnosis and therapy in portal hypertension.

Portal hypertension leads to a wide variety of complications, which lead to significant morbidity and mortality and are some of the leading reasons for liver transplantation in children with chronic liver disease. Evidence-based approaches to the management of adults with portal hypertension exist and have been comprehensively reviewed in a series of international meetings, including the Baveno meetings. Similar evidence-based approaches for the management of portal hypertension in children do not exist and as such international meetings on portal hypertension have not focused on this problem in children. On October 7, 2005 at The Mount Sinai School of Medicine, a panel of pediatric experts reviewed the most recent Baveno statement and crafted a statement modified with their opinions vis a vis approaches to the management of portal hypertension in children.

Mild increases in portal pressure upregulate vascular endothelial growth factor and endothelial nitric oxide synthase in the intestinal microcirculatory bed, leading to a hyperdynamic state.

Increased nitric oxide (NO) is the main factor leading to the hyperdynamic circulation associated with advanced portal hypertension (PHT), but the initial mechanisms and the magnitude of increase in portal pressure required to trigger NO production are not known. We addressed these issues by studying systemic and splanchnic hemodynamics and endothelial NO synthase (eNOS) and VEGF expression in rats with different degrees of portal hypertension. Portal vein ligation (PVL) performed over needles of three different calibers (16-, 18-, and 20-gauge) yielded different degrees of PHT and portosystemic shunting. Compared with sham rats, all three groups of PVL rats exhibited features of hyperdynamic circulation. Rats with minimal portal hypertension (PVL with a 16-gauge needle) showed an early increase in VEGF and eNOS expression selectively at the jejunum. Immunofluorescence showed that VEGF expression was located in highly vascularized areas of the mucosa. Inhibition of VEGF signaling markedly attenuated the increase in eNOS expression. In conclusion, mild increases in portal pressure are enough to upregulate eNOS at the intestinal microcirculation, and this occurs, at least in part, through VEGF upregulation.

The hyperdynamic circulation of chronic liver diseases: from the patient to the molecule.

The hyperdynamic circulatory syndrome observed in chronic liver diseases is a great example of research that originated from clinical observations and progressed in the last 50 years from the patient to the experimental laboratory. Our knowledge has evolved from the patient to the molecule, using experimental models that serve as a source for understanding the complex pathophysiological mechanisms that govern this complex syndrome. We now know that progressive vasodilatation is central to the detrimental effects observed in multiple organs. Although nitric oxide has been shown to be the primary vasodilator molecule in these effects, other molecules also participate in the complex mechanisms of vasodilatation. This review summarizes three major areas: first, clinical observation in patients; second, experimental models used to study the hyperdynamic circulatory syndrome; and third, the vasodilator molecules that play roles in vascular abnormalities observed in portal hypertension.

Histological-hemodynamic correlation in cirrhosis-a histological classification of the severity of cirrhosis.

BACKGROUND/AIMS: While the definitive diagnosis of cirrhosis is histological, it is the degree of portal hypertension, as determined by the hepatic venous pressure gradient (HVPG), that is an important determinant of the severity of cirrhosis. An HVPG > or =10 mmHg (termed clinically significant portal hypertension or CSPH) is predictive of the development of complications of cirrhosis, including death. This study aimed to determine the relationship between specific histological parameters and HVPG in cirrhosis. METHODS: Forty-three patients with biopsy-proven cirrhosis and HVPG measurements within 6 months of the biopsy were included in the study. The following parameters were scored semiquantitatively and without knowledge of HVPG results: sinusoidal fibrosis, septal thickness, loss of portal tracts and central veins, nodule size, inflammation, steatosis, and iron. RESULTS: Septal thickness (p=0.03), small nodularity (p=0.003), loss of portal tracts (p=0.01), inflammation (p=0.04) and alcoholic etiology (p=0.01) correlated with the presence of CSPH. However, small nodularity and septal thickness were the only parameters independently predictive of CSPH (r=0.658, p<0.05). CONCLUSIONS: We describe a subclassification of histological cirrhosis based on the severity of portal hypertension that consists of a combination of nodule size and septal thickness, with small nodularity and thick septa being independent predictors of the presence of CSPH.

I. Veterans Affairs Cooperative Study of polyenylphosphatidylcholine in alcoholic liver disease: effects on drinking behavior by nurse/physician teams.

BACKGROUND: This multicenter prospective, randomized, double-blind placebo-controlled trial was designed to evaluate the effectiveness of polyenylphosphatidylcholine against the progression of liver fibrosis toward cirrhosis in alcoholics. Seven hundred eighty-nine alcoholics with an average intake of 16 drinks per day were enrolled. To control excessive drinking, patients were referred to a standard 12-step-based alcoholism treatment program, but most patients refused to attend. Accordingly, study follow-up procedures incorporated the essential features of the brief-intervention approach. An overall substantial and sustained reduction in drinking was observed. Hepatic histological and other findings are described in a companion article. METHODS: Patients were randomized to receive daily three tablets of either polyenylphosphatidylcholine or placebo. Monthly follow-up visits included an extensive session with a medical nurse along with brief visits with a study physician (hepatologist or gastroenterologist). A detailed physical examination occurred every 6 months. In addition, telephone consultations with the nurse were readily available. All patients had a liver biopsy before entry; a repeat biopsy was scheduled at 24 and 48 months. RESULTS: There was a striking decrease in average daily alcohol intake to approximately 2.5 drinks per day. This was sustained over the course of the trial, lasting from 2 to 6 years. The effect was similar both in early dropouts and long-term patients, i.e., those with a 24-month biopsy or beyond. CONCLUSIONS: In a treatment trial of alcoholic liver fibrosis, a striking reduction in alcohol consumption from 16 to 2.5 daily drinks was achieved with a brief-intervention approach, which consisted of a relative economy of therapeutic efforts that relied mainly on treatment sessions with a medical nurse accompanied by shorter reinforcing visits with a physician. This approach deserves generalization to address the heavy drinking problems commonly encountered in primary care and medical specialty practices.

II. Veterans Affairs Cooperative Study of polyenylphosphatidylcholine in alcoholic liver disease.

BACKGROUND: Polyenylphosphatidylcholine (PPC) has been shown to prevent alcoholic cirrhosis in animals. Our aims were to determine the effectiveness of PPC in preventing or reversing liver fibrosis in heavy drinkers and to assess the extent of liver injury associated with the reduced drinking achieved in these patients. METHODS: This randomized, prospective, double-blind, placebo-controlled clinical trial was conducted in 20 Veterans Affairs Medical Centers with 789 patients (97% male; mean age, 48.8 years) averaging 16 drinks per day (1 drink = 14 g of alcohol) for 19 years. A baseline liver biopsy confirmed the presence of perivenular or septal fibrosis or incomplete cirrhosis. They were randomly assigned either PPC or placebo. Liver biopsy was repeated at 24 months, and the main outcome measure was the stage of fibrosis compared with baseline. Progression was defined as advancing to a more severe stage. RESULTS: The 2-year biopsy was completed in 412 patients. PPC did not differ significantly from placebo in its effect on the main outcome. Alcohol intake was unexpectedly reduced in both groups to approximately 2.5 drinks per day. With this intake, 21.4% advanced at least one stage (22.8% of PPC patients and 20.0% of placebo patients). The hepatitis C virus-positive subgroup exhibited accelerated progression. Improvement in transaminases and bilirubin favoring PPC was seen at some time points in other subgroups (hepatitis C virus-positive drinkers or heavy drinkers). CONCLUSIONS: PPC treatment for 2 years did not affect progression of liver fibrosis. A trend in favor of PPC was seen for transaminases and bilirubin (in subgroups). One of five patients progressed even at moderate levels of drinking, and thus health benefits commonly associated with moderate drinking do not necessarily extend to individuals in the early stages of alcoholic liver disease.

Selective inhibition of tumor microvascular permeability by cavtratin blocks tumor progression in mice.

Tumor vasculature is hyperpermeable to macromolecules compared to normal vasculature; however, the relationship between tumor hyperpermeability and tumor progression is poorly understood. Here we show that a cell-permeable peptide derived from caveolin-1, termed cavtratin, reduces microvascular hyperpermeability and delays tumor progression in mice. These antipermeability and antitumor actions of cavtratin occur in the absence of direct cytostatic or antiangiogenic effects. Cavtratin blocks microvascular permeability by inhibiting endothelial nitric oxide synthase (eNOS), as the antipermeability and antitumor actions of cavtratin are markedly diminished in eNOS knockout mice. Our results support the concepts that hyperpermeability of tumor blood vessels contributes to tumor progression and that blockade of eNOS may be exploited as a novel target for antitumor therapy.

Mice with targeted deletion of eNOS develop hyperdynamic circulation associated with portal hypertension.

Systemic vasodilation is the initiating event of the hyperdynamic circulatory state, being most likely triggered by increased levels of vasodilators, primarily nitric oxide (NO). Endothelial NO synthase (eNOS) is responsible for this event. We tested the hypothesis that gene deletion of eNOS and inducible NOS (iNOS) may inhibit the development of the hyperdynamic circulatory state in portal hypertensive animals. To test this hypothesis, we used mice lacking eNOS (eNOS-/-) or eNOS/iNOS (eNOS/iNOS-/-) genes. A partial portal vein ligation (PVL) was used to induce portal hypertension. Sham-operated animals were used as a control. Hemodynamic characteristics were tested 2 wk after surgery. As opposed to our hypothesis, PVL also caused significant reduction in peripheral resistance in eNOS-/- compared with sham animals (0.33 +/- 0.02 vs. 0.41 +/- 0.03 mmHg. min x kg body wt x ml(-1); P = 0.04) and in eNOS/iNOS-/- animals with PVL compared with that of the sham-operated group (0.44 +/- 0.02 vs. 0.54 +/- 0.04; P = 0.03). This demonstrates that, despite gene deletion of eNOS, the knockout mice developed hyperdynamic circulation. Compensatory vasodilator molecule(s) are upregulated in place of NO in the systemic and splanchnic circulation in portal hypertensive animals.