Portal hypertension: from pathophysiology to clinical practice

Surgical outcomes and survival following esophagectomy for squamous cell carcinoma with or without liver cirrhosis: retrospective cohort study

BACKGROUND AND AIMS

Esophageal squamous cell carcinoma (ESCC) shares common risk factors with liver cirrhosis (LC). The influence of LC in patients with ESCC has not been fully investigated. This study aimed to investigate the postoperative and long-term survival outcomes of esophagectomy for ESCC according to LC presence.

METHODS

Among patients who underwent curative-intent surgery for ESCC between 1994 and 2018, 121 patients with Child-Pugh class A LC and 2810 patients without LC were compared.

RESULTS

Among the LC patients, 73 (60.3%) were diagnosed with LC before surgery and 48 (39.7%) were diagnosed intraoperatively. There were no significant differences in baseline characteristics between patients with LC and those without LC. However, intraoperative blood loss was higher, and operation time, hospital stay, and ICU stay were longer in patients with LC than in those without LC. Moreover, the reoperation, 30-day morbidity (60.6 vs. 73.6%, P =0.006) and 90-day mortality (2.2 vs. 4.9%, P =0.049) were significantly higher in patients with LC. The 5-year overall survival (OS) rate was significantly higher in patients without LC than in those with LC. After adjusting the confounding variables, LC was an adverse risk factor of OS (hazard ratio 1.402, P =0.004). Among patients with LC, the Model of End-Stage Liver Disease score was related to the development of complications of grade more than III (odds ratio 1.459, P =0.013).

CONCLUSION

ESCC patients with Child-Pugh class A LC have high incidences of postoperative morbidity and mortality, and poor OS. Thus, careful patient selection, meticulous operation, and careful postoperative care are needed.

Technique innovation of endoscopic ultrasound portal pressure gradient measurement using standard manometer set for portal hypertension assessment

Portal hypertension (PH) is still a major challenge to be managed in clinical practice. However, hepatic vein pressure gradient (HVPG) measurement is not always reliable for portal hypertension (PH) diagnosis. This study showed the impact of endoscopic ultrasound (EUS) as a promising tool for diagnosis and management PH condition.

Closing spontaneous portosystemic shunts in cirrhosis: Does it make sense? Does it work? What does it take?

Spontaneous portosystemic shunts (SPSS) are an often neglected cause of hepatic encephalopathy associated with cirrhosis. Nowadays, SPSS are considered as radiological biomarkers of clinically significant portal hypertension rather than the previous dogmatic perceived decompressive vessels. SPSS are not rare as they can be diagnosed in over 60% of the patients with cirrhosis by mere contrast-enhanced CT. Moreover, they are clinically relevant since they impact on all portal hypertensive related complications, in particular medically refractory HE, and represent an independent predictor of decompensation and mortality in cirrhosis, irrespective of the type of SPSS. Taken together, these elements warrant strategies to target these shunts directly which is currently is achieved via interventional radiology embolization. In this review, we discuss why it makes sense to tackle SPSS, how to do it and what it takes to do it right based on aggregated literature.

Serum Amyloid Beta42 Is Not Eliminated by the Cirrhotic Liver: A Pilot Study

Amyloid-beta (Aβ) deposition in the brain is the main pathological hallmark of Alzheimer disease. Peripheral clearance of Aβ may possibly also lower brain levels. Recent evidence suggested that hepatic clearance of Aβ42 is impaired in liver cirrhosis. To further test this hypothesis, serum Aβ42 was measured by ELISA in portal venous serum (PVS), systemic venous serum (SVS), and hepatic venous serum (HVS) of 20 patients with liver cirrhosis. Mean Aβ42 level was 24.7 ± 20.4 pg/mL in PVS, 21.2 ± 16.7 pg/mL in HVS, and 19.2 ± 11.7 pg/mL in SVS. Similar levels in the three blood compartments suggested that the cirrhotic liver does not clear Aβ42. Aβ42 was neither associated with the model of end-stage liver disease score nor the Child–Pugh score. Patients with abnormal creatinine or bilirubin levels or prolonged prothrombin time did not display higher Aβ42 levels. Patients with massive ascites and patients with large varices had serum Aβ42 levels similar to patients without these complications. Serum Aβ42 was negatively associated with connective tissue growth factor levels (r = −0.580, p = 0.007) and a protective role of Aβ42 in fibrogenesis was already described. Diabetic patients with liver cirrhosis had higher Aβ42 levels (p = 0.069 for PVS, p = 0.047 for HVS and p = 0.181 for SVS), which is in accordance with previous reports. Present analysis showed that the cirrhotic liver does not eliminate Aβ42. Further studies are needed to explore the association of liver cirrhosis, Aβ42 levels, and cognitive dysfunction.

Modulation of vascular contraction via soluble guanylate cyclase signaling in a novel ex vivo method using rat precision-cut liver slices

Fibrotic processes in the liver of non-alcoholic steatohepatitis (NASH) patients cause microcirculatory dysfunction in the organ which increases blood vessel resistance and causes portal hypertension. Assessing blood vessel function in the liver is challenging, necessitating the development of novel methods in normal and fibrotic tissue that allow for drug screening and translation toward pre-clinical settings. Cultures of precision cut liver slices (PCLS) from normal and fibrotic rat livers were used for blood vessel function analysis. Live recording of vessel diameter was used to assess the response to endothelin-1, serotonin and soluble guanylate cyclase (sGC) activation. A cascade of contraction and relaxation events in response to serotonin, endothelin-1, Ketanserin and sGC activity could be established using vessel diameter analysis of rat PCLS. Both the sGC activator BI 703704 and the sGC stimulator Riociguat prevented serotonin-induced contraction in PCLS from naive rats. By contrast, PCLS cultures from the rat CCl4 NASH model were only responsive to the sGC activator, thus establishing that the sGC enzyme is rendered non-responsive to nitric oxide under oxidative stress found in fibrotic livers. The role of the sGC pathway for vessel relaxation of fibrotic liver tissue was identified in our model. The obtained data shows that the inhibitory capacities on vessel contraction of sGC compounds can be translated to published preclinical data. Altogether, this novel ex vivo PCLS method allows for the differentiation of drug candidates and the translation of therapeutic approaches towards the clinical use.

Cirrhotic Cardiomyopathy: The Interplay Between Liver and Cardiac Muscle. How Does the Cardiovascular System React When the Liver is Diseased?

It is widely known that liver cirrhosis, regardless of the etiologies is accompanied by severe hemodynamic changes. The principal pathophysiological mechanisms are the hyperdynamic circulation with increased cardiac output, heart rate along with reduced systemic vascular resistance. Thus, counteractive mechanisms may develop that eventually lead to systolic as well as diastolic dysfunction and rhythm disturbances, in order to keep a steady homeostasis in the human body.

Literally, blunted contractile responsiveness to physical or pharmacological stress, impaired diastolic relaxation and electrophysiological changes, primarily QT interval prolongation, do occur progressively in a cirrhotic patient with no known preexisting cardiac disease. This condition is identified as cirrhotic cardiomyopathy (CCM), an entity different from that seen in alcoholic cardiac muscle disease.

For the past decades, clinicians did study and attempt to understand the pathophysiology and clinical significance of this process. Indeed, various factors have been identified acting at the molecular and cellular level.

Electrocardiography, echocardiography and various serum biomarkers are the main tools that help healthcare practitioners to point to the correct diagnosis.

Noteworthy, the subjects that suffer from cirrhotic cardiomyopathy may progress to heart failure during invasive procedures such as surgery, insertion of a transjugular intrahepatic portosystemic shunting (TIPS) and liver transplantation. Besides, several studies have illustrated that CCM is a contributing factor, or even a precipitant, of hepatorenal syndrome (HRS), a conceivable reversible kidney failure in patients with liver cirrhosis and ascites.

The treatment is the same as it is in the patients with liver cirrhosis and heart failure and there is no particular treatment for cirrhotic cardiomyopathy. Hence, it is of utmost importance to clearly comprehend the pathophysiology of this disease in order to design more accurate diagnostic tools and definitive treatments in a way to prevent the complications of cirrhosis and overt heart failure.

The objective of this review is to describe in a comprehensive way the pathological alterations that occur in the cardiovascular system of cirrhotic patients. It will also point the limitations that remain in the diagnosis and treatment strategies and more importantly, this review will alert the clinicians in the modern era to further observe and record additional pathological changes in this subset of patients.

Acute-on-Chronic Liver Failure From Chronic-Hepatitis-B, Who Is the Behind Scenes

Acute-on-chronic liver failure (ACLF) is an acute syndrome accompanied with decompensation of cirrhosis, organ failure with high 28-day mortality rate. Systemic inflammation is the main feature of ACLF, and poor outcome is closely related with exacerbated systemic inflammatory responses. It is well known that severe systemic inflammation is an important event in chronic hepatitis B (CHB)-ACLF, which eventually leads to liver injury. However, the initial CHB-ACLF events are unclear; moreover, the effect of these events on host immunity as well as that of immune imbalance on CHB-ACLF progression are unknown. Here, we investigate the initial events of ACLF progression, discuss possible mechanisms underlying ACLF progression, and provide a new model for ACLF prediction and treatment. We review the characteristics of ACLF, and consider its plausible immune predictors and alternative treatment strategies.

Renal disease in the allograft recipient

Chronic renal failure after liver transplantation (LT) is significantly more frequent than after lung or heart transplantation and it results in an increased short and long-term mortality. Renal impairment may occur before LT (functional or due to preexisting parenchymal kidney disease), in the peri-operative period or later after LT. The number of patients with renal failure after LT has increased due to the liver allocation based on MELD and to the more liberal use of higher risk grafts. Calcineurin inhibitor (CNI) nephrotoxicity is the most important cause of renal dysfunction but is a modifiable factor. Strategy to prevent CNI-associated nephrotoxicity is post-op CNI minimization by induction therapy and reduced dose and/or delayed introduction of CNI in combination with mycophenolate mofetil (MMF) or everolimus with no penalty in term of rejection. With everolimus, usually started one month after LT, a drastic minimization of CNI is possible and this results in superior kidney function until at least 3 years follow up. At the moment of renal impairment a drastic reduction of CNI dose together with the introduction of MMF results in an improvement in GFR at 6 to 2 years with a low rate of acute rejection. However, secondary prevention fails to normalize renal function in most of the patients once e GFR <60 ml/min/1.73m²ml.

Evaluation of spleen stiffness in healthy volunteers using point shear wave elastography

INTRODUCTION AND OBJECTIVES

This study aims to measure the values of spleen stiffness (SS) in healthy subjects, the inter-operator agreement in SS measurement, and to detect statistically significant correlations between SS and age, sex, weight, BMI, portal vein dynamics and splenic dimensions.

MATERIALS AND METHODS

The study included 100 healthy volunteers who had no substantial alcohol intake (<30g/daily for man, <20g/daily women), were negative on hepatitis B, hepatitis C, HIV blood serology, and had any history of lymphoproliferative disorders. Abdominal ultrasound, liver and spleen elastography were performed on each patient to search for focal splenic lesions, bile tract or portal vein dilatation, moderate/severe liver steatosis, and to measure liver and spleen stiffness.

RESULTS

The mean value was 18.14 (±3.08) kPa. In the group of men (n=49), the mean was 17.73 (±2.91) kPa, whereas in the group of women (n=51) it was 16.72 (±3.32) kPa. Statistical analyses showed no correlation between spleen stiffness and sex, age, weight, and BMI. Regarding their splenoportal axis, statistically significant differences in SS were found in the means of the two subgroups of subjects stratified by their portal flow velocity (p=0.003) and spleen area (p<0.001). Spearman's rank showed a weak association between SS and portal flow velocty (r=0.271) and splenic area (r=-0.237). ICC showed excellent (0.96) inter-operator agreement and Bland-Altman plot demonstrated no systematic over/under-estimation of spleen stiffness values.

CONCLUSIONS

Our results may serve as a reference point in the evaluation of SS especially in patients affected by advanced liver disease.

Pentraxin-3 is not related to disease severity in cirrhosis and hepatocellular carcinoma patients

The acute-phase protein pentraxin-3 (PTX3) is a component of the innate immune system. Inflammation and tissue injury increased PTX3 in the injured liver, and accordingly, circulating PTX3 was induced in patients with chronic liver diseases. In the present study, PTX3 protein was determined in systemic, hepatic, and portal vein plasma of patients with liver cirrhosis to assess a possible association between hepatic PTX3 release and extent of liver injury. However, PTX3 levels were not related to disease severity. Of note, portal PTX3 levels were higher than concentrations in the hepatic vein. PTX3 in the hepatic and portal veins was negatively correlated with factor V, antithrombin 3, and prothrombin time. PTX3 did neither correlate with C-reactive protein nor galectin-3 or resistin, whereby the latter two proteins are associated with hepatic injury. PTX3 levels were not changed in cirrhosis patients with ascites or varices and did not correlate with the hepatic venous pressure gradient. Likewise, serum PTX3 was not correlated with histological steatosis, inflammation, or fibrosis stage in patients with hepatocellular carcinoma (HCC). Moreover, PTX3 was not associated with tumor node metastasis classification in HCC. Above all, PTX3 increased in hepatic, portal, and systemic blood immediately after transjugular intrahepatic portosystemic shunt (TIPS). Higher PTX3 in portal than hepatic vein plasma and further increase after TIPS suggests that the liver eliminates PTX3 from the circulation. In summary, PTX3 is not of diagnostic value in cirrhosis and HCC patients.

Intractable hepatic encephalopathy in cirrhotic patients: mid-term efficacy of balloon-occluded retrograde portosystemic shunt obliteration

PURPOSE

To evaluate the efficacy and intermediate-term outcome of balloon-occluded retrograde transvenous obliteration (BRTO) for the treatment of hepatic encephalopathy (HE) secondary to portosystemic shunt (PSS) in cirrhotic patients.

MATERIALS AND METHODS

Institutional review board (IRB) approval was obtained for this study and hospital records of patients who underwent BRTO, from August 2011 to August 2015, were analyzed. Based on the inclusion and exclusion criteria, 39 patients (age, 54.07 ± 9.1 years (37-67 years); 33 males and 6 females) with cirrhosis and spontaneous PSS were included. Clinical and laboratory parameters and HE grade were evaluated in all patients before and after the procedure.

RESULTS

Forty sessions of BRTO were attempted in 39 patients. Follow-up imaging revealed complete obliteration of the treated PSS in all patients with clinical success in 37 patients (94.9%). The 1-, 2-, 3-, 4-, 5-, 6-, and 7-year HE-free survival rates among responders were 91.7%, 91.7%, 88.8%, 85.5%, 80.8%, 80.8%, and 80.8% respectively and overall survival rates were 89.7%, 82.1%, 76.9%, 74.4%, 74.4%, 64.8%, and 64.8% respectively. Logistic regression highlighted Child-Turcotte-Pugh (CTP) score at 6 months as a positive predictive factor of HE recurrence with a cutoff of ≥ 9. Five patients (12.8%) had fever and leukocytosis and 1 (2.6%) patient developed spontaneous bacterial peritonitis after the procedure.

CONCLUSION

BRTO is an effective treatment for refractory HE in cirrhotics secondary to large PSS with a few possible complications.

KEY POINTS

• BRTO is an effective and safe treatment for refractory HE, arising from PSS in cirrhotic patients. • Patients with preserved liver function show better outcome and CTP score is the most important predictor of relapse during follow-up.

Plasma renin activity and aldosterone concentration in dogs with acquired portosystemic collaterals

Background

The renin‐angiotensin‐aldosterone system (RAAS) is activated in humans with portal hypertension (PH) associated with liver disease. However, involvement of RAAS in dogs with intrahepatic PH is not clear.

Objective

To measure plasma renin activity (PRA) and plasma aldosterone concentration (PAC) in dogs with PH (chronic hepatitis [CH] and primary hypoplasia of the portal vein [PHPV]), dogs with extrahepatic congenital portosystemic shunt (EH‐CPSS), and healthy dogs and to determine whether the RAAS is activated in dogs with PH.

Animals

Twenty‐seven dogs with acquired portosystemic collaterals (APSCs; 15 dogs with CH, 12 dogs with PHPV), 9 dogs with EH‐CPSS, and 10 healthy dogs.

Methods

Retrospective study. Plasma renin activity and PAC were measured by radioimmunoassay.

Results

Plasma renin activity was significantly higher in the CH group (median, 4.4 ng/mL/h) than in the EH‐CPSS (median, 1.0 ng/mL/h; P < .01) and the healthy (median, 1.1 ng/mL/h; P < .01) groups. No significant differences were found between the PHPV group (median, 2.2 ng/mL/h) and other groups. Plasma aldosterone concentration was significantly higher in the CH (median, 111.0 pg/mL) and PHPV (median, 89.5 pg/mL) groups than in the EH‐CPSS (median, 1.0 pg/mL; P < .001, P < .01, respectively) and healthy (median, 14.5 pg/mL; P < .001, P < .05, respectively) groups.

Conclusions and Clinical Importance

Activation of the RAAS contributes to the pathophysiology of intrahepatic PH in dogs, suggesting that spironolactone may not only be effective for the treatment of ascites but also for the suppression of intrahepatic PH.

Acute on chronic liver failure in non-alcoholic fatty liver and alcohol associated liver disease

Acute on chronic liver failure (ACLF) presents acutely with multiple organ failure and is precipitated by an acute event. The syndrome has high short-term mortality with a potential of returning to baseline liver function if the precipitating event is controlled and patient/s survive the acute event. With heterogeneous definition across the globe of this syndrome, there is a clinical unmet need to homogenize this definition as basis for developing pathogenesis targets, collaboration across countries and centers, and identifying new therapeutic targets. Although, the syndrome can occur in any chronic liver disease with or without cirrhosis, the increasing prevalence of nonalcoholic fatty liver disease (NAFLD) and alcohol associated liver disease (AALD) all across the world, this review will discuss specific issues regarding ACLF among patients with chronic liver disease from NAFLD and ALD.

Potential mechanisms linking gut microbiota and portal hypertension

Gut microbiota is the largest collection of commensal micro-organisms in the human body, engaged in reciprocal cellular and molecular interactions with the liver. This mutually beneficial relationship may break down and result in dysbiosis, associated with disease phenotypes. Altered composition and function of gut microbiota has been implicated in the pathobiology of nonalcoholic fatty liver disease (NAFLD), a prevalent condition linked to obesity, insulin resistance and endothelial dysfunction. NAFLD may progress to cirrhosis and portal hypertension, which is the result of increased intrahepatic vascular resistance and altered splanchnic circulation. Gut microbiota may contribute to rising portal pressure from the earliest stages of NAFLD, although the significance of these changes remains unclear. NAFLD has been linked to lower microbial diversity and weakened intestinal barrier, exposing the host to bacterial components and stimulating pathways of immune defence and inflammation. Moreover, disrupted host-microbial metabolic interplay alters bile acid signalling and the release of vasoregulatory gasotransmitters. These perturbations become prominent in cirrhosis, increasing the risk of clinically significant portal hypertension and leading to bacterial translocation, sepsis and acute-on-chronic liver failure. Better understanding of the gut-liver axis and identification of novel microbial molecular targets may yield specific strategies in the prevention and management of portal hypertension.

Short- and long-term effects of transarterial chemoembolization on portal hypertension in patients with hepatocellular carcinoma

Background

Transarterial chemoembolization (TACE) affects hepatic perfusion, and might have an impact on portal pressure in patients with hepatocellular carcinoma (HCC).

Objective

The objective of this article is to report the secondary outcome “hepatic hemodynamics” from the AVATACE trial, a prospective randomized, placebo-controlled trial on the efficacy of conventional TACE in combination with bevacizumab or placebo.

Methods

Hepatic venous pressure gradient (HVPG) was measured at baseline (prior to first TACE), within nine days (“acute effects”), two months (“intermediate effects”) and six months (“long-term effects”) after the first TACE.

Results

Of 28 patients with early-intermediate stage HCC, n = 20 (71%) had clinically significant portal hypertension (CSPH, HVPG ≥ 10 mmHg) at baseline (median, 12 (interquartile range (IQR): 9–19) mmHg). TACE had neither “acute effects” nor “intermediate effects” on HVPG. However, in 13 patients with available HVPG measurement at month 6, there was a significant increase in HVPG (median, 16 (IQR: 11–19) mmHg) compared with baseline (median, 10 (IQR: 5–12) mmHg; p = 0.007). Portal hypertension-related complications occurred exclusively in patients with CSPH (8 (40%) vs 0).

Conclusions

Repeated TACE was associated with a significant long-term increase in HVPG. This should be considered when deciding whether to continue with TACE or switch to systemic treatment, since CSPH drives the development of complications.

The potential role of vascular alterations and subsequent impaired liver blood flow and hepatic hypoxia in the pathophysiology of non-alcoholic steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) covers a spectrum of disease ranging from steatosis to steatohepatitis (NASH) and fibrosis, but the underlying pathophysiological mechanisms remain largely unknown. As there is currently no approved pharmacological therapy and the prevalence of NAFLD keeps increasing, understanding of its pathophysiology is crucial. We hypothesise that vascular alterations in early NAFLD play a role in the progression of the disease by inducing an increased intrahepatic vascular resistance and consequently relative hypoxia in the liver. Evidence of the detrimental effects of hypoxia in NAFLD has already been observed in liver surgery, where the outcomes of steatotic livers after ischaemia-reperfusion are worse than in healthy livers, and in obstructive sleep apnoea, which is an independent risk factor of NAFLD. Moreover, early histological damage in NAFLD is situated in the pericentral zone, which is also the first zone to be affected by a decreased oxygen tension because of the unique hepatic vacsular anatomy that causes the pericentral oxygen tension to be the lowest. Angiogenesis is also a characteristic of NAFLD, driven by hypoxia-induced mechanisms, as demonstrated in both animal models and in humans with NAFLD. Relative hypoxia is most probably induced by impaired blood flow to the liver, caused by increased intrahepatic vascular resistance. An increased intrahepatic vascular resistance early in the development of disease has been convincingly demonstrated in several animal models of NAFLD, whereas an increased portal pressure, a consequence of increased intrahepatic vascular resistance, has been proven in patients with NAFLD. Animal studies demonstrated a decreased intrahepatic effect of vasodilators and an increased reactivity to vasoconstrictors that results in an increased intrahepatic vascular resistance, thus the presence of a functional component. Pharmacological products that target vasoregulation can hence improve the intrahepatic vascular resistance and this might prevent or reverse progression of NAFLD, representing an important therapeutic option to study. Some of the drugs currently under evaluation in clinical trials for NASH have interesting properties related to the hepatic vasculature. Some other interesting drugs have been tested in animal models but further study in patients with NAFLD is warranted. In summary, in this paper we summarise the evidence that leads to the hypothesis that an increased intrahepatic vascular resistance and subsequent parenchymal hypoxia in early NAFLD is an important pathophysiological driving mechanism for the progression of the disease.

Severe steatosis induces portal hypertension by systemic arterial hyporeactivity and hepatic vasoconstrictor hyperreactivity in rats

Non-alcoholic fatty liver disease (NAFLD) has become the most prevalent chronic liver disease. The presence of portal hypertension has been demonstrated in NAFLD prior to development of inflammation or fibrosis, and is a result of extrahepatic and intrahepatic factors, principally driven by vascular dysfunction. An increased intrahepatic vascular resistance potentially contributes to progression of NAFLD via intralobular hypoxia. However, the exact mechanisms underlying vascular dysfunction in NAFLD remain unknown. This study investigates systemic hemodynamics and both aortic and intrahepatic vascular reactivity in a rat model of severe steatosis. Wistar rats were fed a methionine-choline-deficient diet, inducing steatosis, or control diet for 4 weeks. In vivo hemodynamic measurements, aortic contractility studies, and in situ liver perfusion experiments were performed. The mean arterial blood pressure was lower and portal blood pressure was higher in steatosis compared to controls. The maximal contraction force in aortic rings from steatotic rats was markedly reduced compared to controls. While blockade of nitric oxide (NO) production did not reveal any differences, cyclooxygenase (COX) blockade reduced aortic reactivity in both controls and steatosis, whereas effects were more pronounced in controls. Effects could be attributed to COX-2 iso-enzyme activity. In in situ liver perfusion experiments, exogenous NO donation or endogenous NO stimulation reduced the transhepatic pressure gradient (THPG), whereas NO synthase blockade increased the THPG only in steatosis, but not in controls. Alpha-1-adrenergic stimulation and endothelin-1 induced a significantly more pronounced increase in THPG in steatosis compared to controls. Our results demonstrate that severe steatosis, without inflammation or fibrosis, induces portal hypertension and signs of a hyperdynamic circulation, accompanied by extrahepatic arterial hyporeactivity and intrahepatic vascular hyperreactivity. The arterial hyporeactivity seems to be NO-independent, but appears to be mediated by specific COX-2-related mechanisms. Besides, the increased intrahepatic vascular resistance in steatosis appears not to be NO-related but rather to vasoconstrictor hyperreactivity.

Invasive Hemodynamic Characterization of the Portal-hypertensive Syndrome in Cirrhotic Rats

This is a detailed protocol describing invasive hemodynamic measurements in cirrhotic rats for the characterization of portal hypertensive syndrome. Portal hypertension (PHT) due to cirrhosis is responsible for the most severe complications in patients with liver disease. The full picture of the portal hypertensive syndrome is characterized by increased portal pressure (PP) due to the increased intrahepatic vascular resistance (IHVR), hyperdynamic circulation, and increased splanchnic blood flow. Progressive splanchnic arterial vasodilation and increased cardiac output with elevated heart rate (HR) but low arterial pressure characterizes the portal hypertensive syndrome. Novel therapies are currently being developed that aim to decrease PP by either targeting IHVR or increased splanchnic blood flow - but side effects on systemic hemodynamics may occur. Thus, a detailed characterization of portal venous, splanchnic, and systemic hemodynamic parameters, including measurement of PP, portal venous blood flow (PVBF), mesenteric arterial blood flow, mean arterial pressure (MAP), and HR is needed for preclinical evaluation of the efficacy of novel treatments for PHT. Our video article provides the reader with a structured protocol for performing invasive hemodynamic measurements in cirrhotic rats. In particular, we describe the catheterization of the femoral artery and the portal vein via an ileocolic vein and the measurement of portal venous and splanchnic blood flow via perivascular Doppler-ultrasound flow probes. Representative results of different rat models of PHT are shown.

Origins of Portal Hypertension in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) advanced to cirrhosis is often complicated by clinically significant portal hypertension, which is primarily caused by increased intrahepatic vascular resistance. Liver fibrosis has been identified as a critical determinant of this process. However, there is evidence that portal venous pressure may begin to rise in the earliest stages of NAFLD when fibrosis is far less advanced or absent. The biological and clinical significance of these early changes in sinusoidal homeostasis remains unclear. Experimental and human observations indicate that sinusoidal space restriction due to hepatocellular lipid accumulation and ballooning may impair sinusoidal flow and generate shear stress, increasingly disrupting sinusoidal microcirculation. Sinusoidal endothelial cells, hepatic stellate cells, and Kupffer cells are key partners of hepatocytes affected by NAFLD in promoting endothelial dysfunction through enhanced contractility, capillarization, adhesion and entrapment of blood cells, extracellular matrix deposition, and neovascularization. These biomechanical and rheological changes are aggravated by a dysfunctional gut-liver axis and splanchnic vasoregulation, culminating in fibrosis and clinically significant portal hypertension. We may speculate that increased portal venous pressure is an essential element of the pathogenesis across the entire spectrum of NAFLD. Improved methods of noninvasive portal venous pressure monitoring will hopefully give new insights into the pathobiology of NAFLD and help efforts to identify patients at increased risk for adverse outcomes. In addition, novel drug candidates targeting reversible components of aberrant sinusoidal circulation may prevent progression in NAFLD.

Quantitative analysis of hepatic macro- and microvascular alterations during cirrhogenesis in the rat

Cirrhosis represents the end-stage of any persistent chronically active liver disease. It is characterized by the complete replacement of normal liver tissue by fibrosis, regenerative nodules, and complete fibrotic vascularized septa. The resulting angioarchitectural distortion contributes to an increasing intrahepatic vascular resistance, impeding liver perfusion and leading to portal hypertension. To date, knowledge on the dynamically evolving pathological changes of the hepatic vasculature during cirrhogenesis remains limited. More specifically, detailed anatomical data on the vascular adaptations during disease development is lacking. To address this need, we studied the 3D architecture of the hepatic vasculature during induction of cirrhogenesis in a rat model. Cirrhosis was chemically induced with thioacetamide (TAA). At predefined time points, the hepatic vasculature was fixed and visualized using a combination of vascular corrosion casting and deep tissue microscopy. Three-dimensional reconstruction and data-fitting enabled cirrhogenic features to extracted at multiple scales, portraying the impact of cirrhosis on the hepatic vasculature. At the macrolevel, we noticed that regenerative nodules severely compressed pliant venous vessels from 12 weeks of TAA intoxication onwards. Especially hepatic veins were highly affected by this compression, with collapsed vessel segments severely reducing perfusion capabilities. At the microlevel, we discovered zone-specific sinusoidal degeneration, with sinusoids located near the surface being more affected than those in the middle of a liver lobe. Our data shed light on and quantify the evolving angioarchitecture during cirrhogenesis. These findings may prove helpful for future targeted invasive interventions.

Hepatic encephalopathy: causes and health-related burden

Patients with cirrhosis are at risk of hepatic encephalopathy (HE). While its pathogenesis is not fully understood, the circulation of increased levels of ammonia through the bloodstream to the brain is thought to be a key causative factor. The ammonia penetrates the blood-brain barrier, ultimately leading to cerebral oedema. This can result in cognitive impairments, which can exhibit in multiple ways, adversely affecting quality of life for both patients and their families. The need for hospitalisation and longer hospital stays associated with HE has cost implications for the health service. Treatment revolves around the reduction of ammonia levels in the bloodstream.

The use of obeticholic acid for the management of non-viral liver disease: current clinical practice and future perspectives

Farnesoid X nuclear receptor is involved in the regulation of lipid and glucose metabolism, though mainly in the homeostasis of bile acids. Indeed, the agonists of farnesoid X nuclear receptor represent promising drugs. Areas covered: Obeticholic acid, a novel semisynthetic analogue of the naturally occurring bile acid, has led to encouraging preliminary results in both cholestatic and metabolic liver disease. In patients with primary biliary cholangitis, obeticholic acid determines a significant biochemical improvement although the effects on liver fibrosis are lacking. Obeticholic acid has been suggested for the treatment of nonalcoholic liver disease with good laboratory results. In cirrhotic animal models, the drug seems to reduce both portal hypertension and gut bacterial translocation. Expert commentary: The use of obeticholic acid for the treatment of primary biliary cholangitis shows satisfying results. However, some open questions remain unresolved. Herein, we provide an overview of the current knowledge about the use of obeticholic acid in the field of nonviral chronic liver diseases. We tried to give a global point of view using a translational approach.

Beneficial long term effect of a phosphodiesterase-5-inhibitor in cirrhotic portal hypertension: A case report with 8 years follow-up

Non-selective beta-blockers are the mainstay of medical therapy for portal hypertension in liver cirrhosis. Inhibitors of phosphodiesterase-5 (PDE-5-inhibitors) reduce portal pressure in the acute setting by > 10% which may suggest a long-term beneficial effect. Currently, there is no available data on long-term treatment of portal hypertension with PDE-5-inhibitors. This case of a patient with liver cirrhosis secondary to autoimmune liver disease with episodes of bleeding from esophageal varices is the first documented case in which a treatment with a PDE-5-inhibitor for eight years was monitored. In the acute setting, the PDE-5-inhibitor Vardenafil lowered portal pressure by 13%. The portal blood flow increased by 28% based on Doppler sonography and by 16% using MRI technique. As maintenance medication the PDE-5-inhibitor Tadalafil was used for eight consecutive years with comparable effects on portal pressure and portal blood flow. There were no recurrence of bleeding and no formation of new varices. Influencing the NO-pathway by the use of PDE-5 inhibitors may have long-term beneficial effects in compensated cirrhosis.

Adipokines in Liver Cirrhosis

Liver fibrosis can progress to cirrhosis, which is considered a serious disease. The Child-Pugh score and the model of end-stage liver disease score have been established to assess residual liver function in patients with liver cirrhosis. The development of portal hypertension contributes to ascites, variceal bleeding and further complications in these patients. A transjugular intrahepatic portosystemic shunt (TIPS) is used to lower portal pressure, which represents a major improvement in the treatment of patients. Adipokines are proteins released from adipose tissue and modulate hepatic fibrogenesis. These proteins affect various biological processes that are involved in liver function, including angiogenesis, vasodilation, inflammation and deposition of extracellular matrix proteins. The best studied adipokines are adiponectin and leptin. Adiponectin protects against hepatic inflammation and fibrogenesis, and leptin functions as a profibrogenic factor. These and other adipokines are supposed to modulate disease severity in patients with liver cirrhosis. Consequently, circulating levels of these proteins have been analyzed to identify associations with parameters of hepatic function, portal hypertension and its associated complications in patients with liver cirrhosis. This review article briefly addresses the role of adipokines in hepatitis and liver fibrosis. Here, studies having analyzed these proteins in systemic blood in cirrhotic patients are listed to identify adipokines that are comparably changed in the different cohorts of patients with liver cirrhosis. Some studies measured these proteins in systemic, hepatic and portal vein blood or after TIPS to specify the tissues contributing to circulating levels of these proteins and the effect of portal hypertension, respectively.

Endoscopic variceal ligation combined with argon plasma coagulation versus ligation alone for the secondary prophylaxis of variceal bleeding: a systematic review and meta-analysis

Endoscopic variceal ligation (EVL) is often recommended as an effective method for the treatment of esophageal varices, despite the important tendency of variceal recurrence. Recent studies indicate that combining EVL with argon plasma coagulation (APC) may be a more effective therapy than ligation alone. To investigate these findings, we carried out a systematic review and meta-analysis to compare the safety and efficacy of EVL combined with APC versus ligation alone for the secondary prophylaxis of esophageal variceal hemorrhage. All studies were searched through PubMed, the Cochrane Library, and Science Direct. The outcome measures were relative risk (RR) or risk difference with 95% confidence intervals (CIs) for dichotomous data and standardized mean difference for continuous data. Heterogeneity was calculated using the χ and the I-tests. Two investigators independently identified four randomized-controlled trials included in the research. The variceal recurrence rate was significantly lower in the combined therapy group (RR=0.19, 95% CI: 0.09-0.41, P=0.000). The bleeding recurrence and mortalities in the two groups showed no significant differences (RR=0.29, 95% CI: 0.08-1.04, P=0.058; risk difference=-0.02, 95% CI: -0.08-0.04, P=0.576, respectively). Although the pyrexia incidence rate was significantly higher in the combined group (RR=3.42, 95% CI: 1.56-7.48, P=0.002), there was intertrial heterogeneity (I=52.5%, P=0.097). EVL combined with APC is superior to ligation alone for endoscopic variceal recurrence without severe adverse events in secondary prophylaxis against esophageal variceal bleeding. More high-quality studies are needed to strengthen this conclusion.

Novel treatment options for portal hypertension

Portal hypertension is most frequently associated with cirrhosis and is a major driver for associated complications, such as variceal bleeding, ascites or hepatic encephalopathy. As such, clinically significant portal hypertension forms the prelude to decompensation and impacts significantly on the prognosis of patients with liver cirrhosis. At present, non-selective β-blockers, vasopressin analogues and somatostatin analogues are the mainstay of treatment but these strategies are far from satisfactory and only target splanchnic hyperemia. In contrast, safe and reliable strategies to reduce the increased intrahepatic resistance in cirrhotic patients still represent a pending issue. In recent years, several preclinical and clinical trials have focused on this latter component and other therapeutic avenues. In this review, we highlight novel data in this context and address potentially interesting therapeutic options for the future.

Time to viral suppression is not related to achievement of SVR12 in HCV GT1-infected patients treated with ombitasvir/paritaprevir/ritonavir and dasabuvir with or without ribavirin

High rates of sustained virologic response at post-treatment week 12 (SVR12) were achieved in six phase 3 trials of ombitasvir (OBV, an NS5A inhibitor), paritaprevir (an NS3/4A protease inhibitor) co-dosed with ritonavir (PTV/r) + dasabuvir (DSV, an NS5B RNA polymerase inhibitor) (ie, 3D regimen) with or without ribavirin (RBV) in adults with chronic genotype (GT) 1 hepatitis C virus (HCV) infection. We assessed whether time to first HCV RNA value below the lower limit of quantification in patients with and without cirrhosis was associated with achievement of SVR12. Data were analysed from GT1-infected patients enrolled in six phase 3 studies of 3D ± RBV. Patients who experienced non-virologic failure were excluded from analysis. HCV RNA was determined using the Roche COBAS TaqMan RT-PCR assay (lower limit of quantification, LLOQ =25 IU/mL). SVR12 was analysed by week of first HCV RNA suppression, defined as HCV RNA <LLOQ. The analysis included a total of 2027 patients. Cumulative proportions of subjects with initial HCV RNA suppression <LLOQ at weeks 1, 2, 4 and 6 were 31%, 81%, 99% and 100%, respectively. SVR12 was achieved by 98%, 97%, 98% and 92% of patients with initial suppression at Weeks 1, 2, 4 and 6, respectively (P=.42, trend test). Across six phase 3 trials of 3D ± RBV, most patients achieved viral suppression by week 2. Time to viral suppression was not associated with subsequent achievement of SVR12, suggesting that on-treatment virologic monitoring may not be necessary with this regimen.

FXR agonist obeticholic acid reduces hepatic inflammation and fibrosis in a rat model of toxic cirrhosis

Hepatic inflammation drives hepatic stellate cells (HSC), resulting in liver fibrosis. The Farnesoid-X receptor (FXR) antagonizes inflammation through NF-κB inhibition. We investigated preventive and therapeutic effects of FXR agonist obeticholic acid (OCA) on hepatic inflammation and fibrosis in toxic cirrhotic rats. Cirrhosis was induced by thioacetamide (TAA) intoxication. OCA was given during or after intoxication with vehicle-treated rats as controls. At sacrifice, fibrosis, hemodynamic and biochemical parameters were assessed. HSC activation, cell turn-over, hepatic NF-κB activation, pro-inflammatory and pro-fibrotic cytokines were determined. The effect of OCA was further evaluated in isolated HSC, Kupffer cells, hepatocytes and liver sinusoidal endothelial cells (LSEC). OCA decreased hepatic inflammation and fibrogenesis during TAA-administration and reversed fibrosis in established cirrhosis. Portal pressure decreased through reduced intrahepatic vascular resistance. This was paralleled by decreased expression of pro-fibrotic cytokines (transforming growth-factor β, connective tissue growth factor, platelet-derived growth factor β-receptor) as well as markers of hepatic cell turn-over, by blunting effects of pro-inflammatory cytokines (e.g. monocyte chemo-attractant protein-1). In vitro, OCA inhibited both LSEC and Kupffer cell activation; while HSC remained unaffected. This related to NF-κB inhibition via up-regulated IκBα. In conclusion, OCA inhibits hepatic inflammation in toxic cirrhotic rats resulting in decreased HSC activation and fibrosis.

Hemodynamic Response to Carvedilol is Maintained for Long Periods and Leads to Better Clinical Outcome in Cirrhosis: A Prospective Study

BACKGROUND

Non-selective beta-blockers (NSBBs), e.g. propranolol, are recommended for prophylaxis of variceal bleeding in cirrhosis. Carvedilol, a newer NSBB with additional anti-α1-adrenergic activity, is superior to propranolol in reducing portal pressure. Repeated HVPG measurements are required to identify responders to NSBB. We aimed to determine whether a single-time HVPG measurement, using acute-hemodynamic-response-testing, is sufficient to predict long-term response to carvedilol, and whether these responders have better clinical outcome.

METHODS

Consecutive patients with cirrhosis, aged 18-70 years, in whom NSBB was indicated for primary/secondary prophylaxis of variceal bleeding, and who underwent HVPG were included. Acute-hemodynamic-response was defined as a decrease in HVPG ≥10% from baseline or absolute HVPG value declining to <12 mm Hg, 1 h after 25 mg oral carvedilol. The aims of the study were to determine: the proportion of patients who achieved acute-hemodynamic-response to carvedilol; whether HVPG-response is maintained for 6 months; and clinical outcome of acute-responders to carvedilol therapy for 6 months.

RESULTS

The study included 69 patients (median age 51, males 93%). Alcohol was the most common etiology; 59% patients belonged to Child-Pugh class B. NSBB was indicated for primary prophylaxis in 36% and secondary prophylaxis in 64% patients. According to the response criteria, 67% patients were found to be acute-hemodynamic-responders. At 6 months, 92% patients were found to be still maintaining their hemodynamic response to carvedilol. Using intention-to-treat analysis, 76% patients maintained their response. These acute responders, on chronic treatment with carvedilol during the 6-month period, had lesser episodes of variceal bleeding, better ascites control, and improved MELD and CTP scores, than non-carvedilol treated non-responders. However, survival remained similar in both the groups.

CONCLUSIONS

A single-time HVPG measurement with acute-hemodynamic-response-testing is simple and reliable method for identifying patients who are more likely to respond to carvedilol therapy. The HVPG-response is maintained over a long period in majority of these patients and carvedilol therapy leads to better clinical outcome in these patients.

Cancer and liver cirrhosis: implications on prognosis and management

Liver cirrhosis, the end-stage of every chronic liver disease, is not only the major risk factor for the development of hepatocellular carcinoma but also a limiting factor for anticancer therapy of liver and non-hepatic malignancies. Liver cirrhosis may limit surgical and interventional approaches to cancer treatment, influence pharmacokinetics of anticancer drugs, increase side effects of chemotherapy, render patients susceptible for hepatotoxicity, and ultimately result in a competitive risk for morbidity and mortality. In this review, we provide a concise overview about the impact of liver cirrhosis on the management and prognosis of patients with primary liver cancer or non-hepatic malignancies.

Cardiac imaging in patients with chronic liver disease

Cirrhotic cardiomyopathy (CCM) is characterized by an impaired contractile response to stress, diastolic dysfunction and the presence of electrophysiological abnormalities, and it may be diagnosed at rest in some patients or demasked by physiological or pharmacological stress. CCM seems to be involved in the development of hepatic nephropathy and is associated with an impaired survival. In the field of cardiac imaging, CCM is not yet a well-characterized entity, hence various modalities of cardiac imaging have been applied. Stress testing with either physiologically or pharmacologically induced circulatory stress has been used to assess systolic dysfunction. Whereas echocardiography with tissue Doppler is by far the most preferred method to detect diastolic dysfunction with measurement of E/A- and E/E'-ratio. In addition, echocardiography may also possess the potential to evaluate systolic dysfunction at rest by application of new myocardial strain techniques. Experience with other modalities such as cardiac magnetic resonance imaging and cardiac computed tomography is limited. Future studies exploring these imaging modalities are necessary to characterize and monitor the cardiac changes in cirrhotic patients.

Blunted cardiac response to hemorrhage in cirrhotic rats is mediated by local macrophage-released endocannabinoids

BACKGROUND & AIMS

Cirrhosis is associated with blunted cardiovascular response to stimuli such as hemorrhage, but the mechanism remains unclear. We aimed to clarify the role of endocannabinoids in blunted hemorrhage response in cirrhotic rats.

METHODS

Cirrhosis was induced by bile duct ligation (BDL). Hemodynamics were measured. Cannabinoid receptor-1 (CB1) antagonist, AM251, and macrophage inhibitor gadolinium chloride (GdCl3) were administered. Myocardial levels of anandamide (AEA) and 2-arachidonoyl glycerol (2-AG) were measured and resident monocytes and macrophages quantified by immunohistochemistry. Isolated cardiomyocyte contractility was measured before and after incubation with monocytes from BDL and sham controls.

RESULTS

Hemorrhage significantly decreased arterial pressure and left ventricular dP/dT. After hemorrhage, these changes quickly reversed in controls, but were severely prolonged in BDL rats. Chronic AM251 treatment restored this impaired response. AEA and 2-AG levels were increased in BDL hearts and further increased after hemorrhage. Sham hearts showed virtually no monocytes or macrophages before or after hemorrhage, whereas BDL hearts had significantly more white blood cells which further increased after hemorrhage. GdCl3 treatment significantly reduced cardiac endocannabinoid levels both at baseline and after hemorrhage. This treatment also restored cardiovascular response to hemorrhage in BDL rats but did not affect sham controls. Monocytes isolated from BDL rats more potently inhibited cardiomyocyte contractility than sham control monocytes.

CONCLUSIONS

The cirrhotic heart showed increased monocyte recruitment and endocannabinoid levels. CB1 blockade or GdCl3 treatment restored blunted cardiovascular response to hemorrhage. Endocannabinoids released by monocytes blunt cardiac response to hemorrhage. Preventing monocyte recruitment or blocking endocannabinoid signaling may improve cardiovascular homeostasis in cirrhosis.

The Beneficial Effects of P2X7 Antagonism in Rats with Bile Duct Ligation-induced Cirrhosis

Splanchnic angiogenesis in liver cirrhosis often leads to complications as gastroesophageal variceal hemorrhage and the treatment efficacy is adversely affected by poor portal-systemic collateral vasoresponsiveness related to nitric oxide (NO). Purinergic receptor subtype P2X7 participates in the modulation of inflammation, angiogenesis, fibrogenesis and vasoresponsiveness, but the relevant influence in cirrhosis is unknown. Common bile duct-ligated (CBDL) or sham-operated Spraque-Dawley rats received brilliant blue G (BBG, a P2X7 antagonist and food additive) or vehicle from the 15th to 28th day after operations, then hemodynamics, mesenteric angiogenesis, portal-systemic shunting, liver fibrosis, and protein expressions of angiogenic and fibrogenic factors were evaluated. The influence of oxidized ATP (oATP, another P2X7 receptor antagonist) on the collateral vasoresponsiveness to arginine vasopressin (AVP) was also surveyed. BBG decreased superior mesenteric artery (SMA) flow, portal-systemic shunting, mesenteric vascular density, and mesenteric protein expressions of vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2), phospho (p)-VEGFR2, platelet-derived growth factor (PDGF), PDGF receptor beta (PDGFRβ), cyclooxygenase (COX)-1, COX-2, and endothelial NO synthase (eNOS) in CBDL rats. BBG also ameliorated liver fibrosis and down-regulated hepatic interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), PDGF, IL-1β, transforming growth factor-beta (TGF-β), p-extracellular-signal-regulated kinases (ERK), and alpha-smooth muscle actin (α-SMA) expressions in CBDL rats. The collateral vasocontractility to AVP was enhanced by oATP. oATP down-regulated eNOS, inducible NOS (iNOS), VEGF, Akt, p-Akt, and nuclear factor-kappa B (NF-κB) expressions in splenorenal shunt, the most prominent intra-abdominal collateral vessel in rodents. P2X7 antagonism alleviates splanchnic hyperemia, severity of portal-systemic shunting, mesenteric angiogenesis, liver fibrosis, and enhances portal-systemic collateral vasoresponsiveness in cirrhotic rats. P2X7 blockade may be a feasible strategy to control cirrhosis and complications.

Endothelial dysfunction in cirrhosis: Role of inflammation and oxidative stress

This review describes the recent developments in the pathobiology of endothelial dysfunction (ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED has prognostic implications by predicting unfavourable early hepatic events and mortality in patients with portal hypertension and advanced liver diseases. ED characterised by an impaired bioactivity of nitric oxide (NO) within the hepatic circulation and is mainly due to decreased bioavailability of NO and accelerated degradation of NO with reactive oxygen species. Furthermore, elevated inflammatory markers also inhibit NO synthesis and causes ED in cirrhotic liver. Therefore, improvement of NO availability in the hepatic circulation can be beneficial for the improvement of endothelial dysfunction and associated portal hypertension in patients with cirrhosis. Furthermore, therapeutic agents that are identified in increasing NO bioavailability through improvement of hepatic endothelial nitric oxide synthase (eNOS) activity and reduction in hepatic asymmetric dimethylarginine, an endogenous modulator of eNOS and a key mediator of elevated intrahepatic vascular tone in cirrhosis would be interesting therapeutic approaches in patients with endothelial dysfunction and portal hypertension in advanced liver diseases.

The phosphodiesterase-5-inhibitor udenafil lowers portal pressure in compensated preascitic liver cirrhosis. A dose-finding phase-II-study

BACKGROUND

Phosphodiesterase-5-inhibitors may lower portal pressure.

AIMS

To investigate the effect of the phosphodiesterase-5-inhibitor udenafil on hepatic and systemic haemodynamics in liver cirrhosis.

METHODS

In an open-label phase-II-study, patients with liver cirrhosis Child A/B and hepatic venous pressure-gradient ≥ 12 mmHg received 12.5mg/day, 25mg/day, 50mg/day, 75 mg/day (n = 5, each), or 100mg/day (n = 10) udenafil p.o. for one week. On days 0 and 6, hepatic venous pressure-gradient was measured prior to and one hour after drug ingestion. Endpoints were reduction of hepatic venous pressure-gradient from day 0 pre to day 6 post intake and reduction in the acute setting. Pharmacokinetics were measured in the two lowest dosage groups.

RESULTS

Combining the 75 and 100mg/day groups hepatic venous pressure-gradient reduction after drug intake was 19.9% (p = 0.0006) on day 0. From day 0 pre-dose to day 6 post-dose hepatic venous pressure-gradient decreased by 15.7% (p = 0.040) and in 5/15 patients by ≥ 20% or to <12 mmHg. In the 100mg/day group, mean arterial pressure decreased from 98.9 mmHg by 6.2 mmHg (p = 0.037) from day 0 pre-dose to day 6 post-dose. Heart rates or electrocardiograms were unchanged. Udenafil was eliminated with t1/2 = 25 h.

CONCLUSIONS

Oral application of 75-100mg of the phosphodiesterase-5-inhibitor udenafil lowers portal pressure in the acute setting by about 20% without relevant systemic cardiovascular side effects.

Reduced serum chemerin in patients with more severe liver cirrhosis

Chemerin is a well-established modulator of immune cell function and its serum levels are induced in inflammatory diseases. Liver cirrhosis is associated with inflammation which is aggravated by portal hypertension. The objective of this study was to evaluate whether chemerin is induced in patients with more severe liver cirrhosis and portal hypertension. Chemerin has been measured by ELISA in the portal venous serum (PVS), systemic venous serum (SVS) and hepatic venous serum (HVS) of 45 patients with liver cirrhosis. Chemerin is higher in HVS compared to PVS in accordance with our recently published finding. SVS, HVS and PVS chemerin decline in patients with more advanced liver injury defined by the CHILD-PUGH score. Hepatic chemerin has been determined in a small cohort and is similarly expressed in normal and cirrhotic liver. MELD score and serum markers of liver and kidney function do not correlate with chemerin. There is a positive correlation of chemerin in all compartments with Quick prothrombin time and of SVS chemerin with systolic blood pressure. PVS chemerin is induced in patients with modest/massive ascites but this does not translate into higher HVS and SVS levels. Chemerin is not associated with variceal size. Reduction of portal pressure by transjugular intrahepatic portosystemic shunt does not affect chemerin levels. These data show that low chemerin in patients with more severe liver cirrhosis is associated with reduced Quick prothrombin time.

Hepatic hemodynamic changes during liver transplantation: A review

Liver transplantation is performed in the recent decades with great improvements not only technically but also conceptually. However, there is still lack of consensus about the optimal hemodynamic characteristics during liver transplantation. The representative hemodynamic parameters include portal vein pressure, portal vein flow, and hepatic venous pressure gradient; however, there are still others potential valuable parameters, such as total liver inflow and hepatic artery flow. All the parameters are correlated closely and some internal modulating mechanisms, like hepatic arterial buffer response, occur to maintain stable hepatic inflow. To distinguish the unique importance of each hepatic and systemic parameter in different states during liver transplantation, we reviewed the published data and also conducted two transplant cases with different surgical strategies applied to achieve ideal portal inflow and pressure.

Prostacyclin decreases splanchnic vascular contractility in cirrhotic rats

BACKGROUND

Prostacyclin has been shown to increase portal hypertension, but the mechanism is unclear. This study aimed to investigate whether the overproduction of prostacyclin (PGI2) in cirrhosis participates in the splanchnic vascular hyporesponsiveness to vasoconstrictors in cirrhotic rats.

METHODS

Cirrhotic model was created by subcutaneous injection of 60% carbon tetrachloride (CCl4) corn oil solution combined with intermittent drinking of 5% alcohol, and age-matched rats served as controls. The isolated third-generation mesenteric arterioles were used to examine the contractile response to norepinephrine. The changes in vascular diameter were observed under a microscope imaging device. The plasma concentration of 6-ketone-prostaglandin F1alpha (6-keto-PGF1alpha, a stable metabolite of PGI2) was tested via enzyme immunoassays and the expression of cyclooxygenase (COX) in mesenteric arteries was detected by Western blotting.

RESULTS

In parallel with the increase of plasma 6-keto-PGF1alpha, the contractile response of arterioles from cirrhotic rats to norepinephrine was significantly impaired compared with that from controls. Inhibition of PGI2 or protein kinase A with indomethacin or Rp-adenosine 3', 5'-cyclic monophosphothioate (Rp-cAMPS) partially reversed the vascular hypo-contractile response to norepinephrine in arterioles from cirrhotic rats. Indomethacin significantly decreased the plasma 6-keto-PGF1alpha. Furthermore, indomethacin significantly attenuated the effect of Rp-cAMPS on arterioles from cirrhotic rats. COX-1 expression was up-regulated in mesenteric arteries from cirrhotic rats, whereas COX-2 was not detectable in the mesenteric arteries from both cirrhotic and control rats.

CONCLUSION

Enhanced COX-1 expression in cirrhotic rats resulted in elevated PGI2 production which partially contributed to the splanchnic vascular hyporesponsiveness to a vasoconstrictor via the protein kinase A pathway.

Obeticholic acid, a farnesoid X receptor agonist, improves portal hypertension by two distinct pathways in cirrhotic rats

The farnesoid X receptor (FXR) is a nuclear bile acid receptor involved in bile acid homeostasis, hepatic and intestinal inflammation, liver fibrosis, and cardiovascular disease. We studied the effect of short-term treatment with obeticholic acid (INT-747), a potent selective FXR agonist, on intrahepatic hemodynamic dysfunction and signaling pathways in different rat models of cirrhotic portal hypertension (PHT). For this, thioacetamide (TAA)-intoxicated and bile-duct-ligated (BDL) rats were used as models. After gavage of two doses of 30 mg/kg of INT-747 or vehicle within 24 hours, in vivo hemodynamics were assessed. Additionally, we evaluated the direct effect of INT-747 on total intrahepatic vascular resistance (IHVR) and intrahepatic vascular tone (endothelial dysfunction and hyperresponsiveness to methoxamine) by means of an in situ liver perfusion system and on hepatic stellate cell contraction in vitro. FXR expression and involved intrahepatic vasoactive pathways (e.g., endothelial nitric oxide synthase [eNOS], Rho-kinase, and dimethylarginine dimethylaminohydrolase [DDAH]) were analyzed by immunohistochemistry, reverse-transcriptase polymerase chain reaction, or western blotting. In both cirrhotic models, FXR expression was decreased. Treatment with INT-747 in TAA and BDL reactivated the FXR downstream signaling pathway and decreased portal pressure by lowering total IHVR without deleterious systemic hypotension. In the perfused TAA and BDL cirrhotic liver, INT-747 improved endothelial vasorelaxation capacity, but not hyperresponsiveness. In both groups, this was associated with an increased eNOS activity, which, in TAA, related to down-regulation of Rho-kinase and in BDL to up-regulation of DDAH-2.

CONCLUSION

FXR agonist INT-747 improves PHT in two different rat models of cirrhosis by decreasing IHVR. This hemodynamic effect relates to increased intrahepatic eNOS activity by pathways that differ depending on the etiology of cirrhosis.

Cirrhotic cardiomyopathy: pathogenesis and clinical relevance

Cirrhosis is known to cause alterations in the systemic haemodynamic system. Cirrhotic cardiomyopathy designates a cardiac dysfunction that includes impaired cardiac contractility with systolic and diastolic dysfunction, as well as electromechanical abnormalities in the absence of other known causes of cardiac disease. This condition is primarily revealed by inducing physical or pharmacological stress, but echocardiography is excellent at revealing diastolic dysfunction and might also be used to detect systolic dysfunction at rest. Furthermore, measurement of circulating levels of cardiac biomarkers could improve the diagnostic assessm+ent. Cirrhotic cardiomyopathy contributes to various complications in cirrhosis, especially as an important factor in the development of hepatic nephropathy. Additionally, cirrhotic cardiomyopathy seems to be associated with the development of heart failure in relation to invasive procedures such as shunt insertion and liver transplantation. Current pharmacological treatment is nonspecific and directed towards left ventricular failure, and liver transplantation is currently the only proven treatment with specific effect on cirrhotic cardiomyopathy.

Effects of fasudil on the portal and systemic hemodynamics of patients with cirrhosis

BACKGROUND AND AIM

Fasudil, a Rho-kinase inhibitor, has been shown to reduce portal venous pressure in cirrhotic rats. However, its effects on portal and systemic hemodynamics have not been investigated in cirrhotic patients with portal hypertension. The aim of this study was to assess the effects of fasudil on the portal and systemic hemodynamics of cirrhotic patients with portal hypertension.

METHODS

Twenty-three patients with cirrhosis and portal hypertension were studied. Systemic and portal hemodynamics were measured prior to and 50 min after the initiation of intravenous administration of 30 mg fasudil (n = 15) or placebo (n = 8).

RESULTS

After fasudil, there were significant decreases in both mean arterial pressure (P < 0.05) and systemic vascular resistance (P < 0.05), whereas the heart rate increased significantly (P < 0.05). There was a significant decrease in the hepatic venous pressure gradient (P < 0.05). Portal vascular resistance also decreased significantly (P < 0.01). Placebo caused no significant effects. There were no symptomatic reactions caused by changes in the mean arterial pressure or heart rate after fasudil.

CONCLUSIONS

In cirrhotic patients with portal hypertension, fasudil lowers portal vascular resistance, resulting in decreased portal venous pressure with reducing arterial pressure.

Portal vein omentin is increased in patients with liver cirrhosis but is not associated with complications of portal hypertension

BACKGROUND

Omentin is a visceral fat-derived adipokine associated with endothelium-dependent vasodilation. Impaired endothelial function is a major cause of portal hypertension in liver cirrhosis. The aim was to assess associations of omentin with systemic markers of endothelial function, namely arginine and asymmetric dimethylarginine (ADMA) and complications of portal hypertension in liver cirrhosis.

MATERIALS AND METHODS

Systemic omentin was measured by ELISA in portal venous serum (PVS), systemic venous serum (SVS) and hepatic venous serum (HVS) of 40 patients with liver cirrhosis and 10 liver-healthy controls. ADMA and arginine were determined in SVS of the patients by ELISA.

RESULTS

Omentin is elevated in PVS and tends to be increased in SVS and HVS of patients with liver cirrhosis compared with controls. Omentin is principally expressed in visceral fat, and PVS omentin tends to be higher than SVS levels. Lower HVS than PVS omentin suggests that omentin may be partly removed from the circulation by the liver. Omentin in serum is not associated with stages of liver cirrhosis defined by CHILD-POUGH or MELD score and is not affected in patients with ascites. HVS omentin tends to be reduced in patients with large varices compared with patients without/with small varices. Arginine/ADMA ratio is reduced in patients with massive ascites but is not associated with variceal size. Further, Arginine/ADMA ratio does not correlate with omentin.

CONCLUSION

Current data show that PVS omentin is increased in liver cirrhosis but is not associated with complications of portal hypertension.

Embolization of large spontaneous portosystemic shunts for refractory hepatic encephalopathy: a multicenter survey on safety and efficacy

Refractory hepatic encephalopathy (HE) remains a major cause of morbidity in cirrhosis patients. Large spontaneous portosystemic shunts (SPSSs) have been previously suggested to sustain HE in these patients. We aimed to retrospectively assess the efficacy and safety of patients treated with embolization of large SPSSs for the treatment of chronic therapy-refractory HE in a European multicentric working group and to identify patients who may benefit from this procedure. Between July 1998 and January 2012, 37 patients (Child A6-C13, MELD [Model of Endstage Liver Disease] 5-28) with refractory HE were diagnosed with single large SPSSs that were considered eligible for embolization. On a short-term basis (i.e., within 100 days after embolization), 22 out of 37 patients (59.4%) were free of HE (P < 0.001 versus before embolization) of which 18 (48.6% of patients overall) remained HE-free over a mean follow-up period of 697 ± 157 days (P < 0.001 versus before embolization). Overall, we noted improved autonomy, decreased number of hospitalizations, and severity of the worst HE episode after embolization in three-quarters of the patients. Logistic regression identified the MELD score as strongest positive predictive factor of HE recurrence with a cutoff of 11 for patient selection. As to safety, we noted one major nonlethal procedure-related complication. There was no significant increase in de novo development or aggravation of preexisting varices, portal hypertensive gastropathy, or ascites.

CONCLUSION

This multicenter European cohort study demonstrated a role for large SPSSs in chronic protracted or recurrent HE and substantiated the effectiveness and safety of embolization of these shunts, provided there is sufficient functional liver reserve.

Branched-chain amino acids alleviate nonalcoholic steatohepatitis in rats

Nonalcoholic steatohepatitis (NASH) is a prevalent disease in countries around the world. The branched-chain amino acids (BCAAs) leucine, isoleucine, and valine cannot be synthesized by the body and have been shown to promote muscle buildup; thus, it is logical to suggest that BCAAs can reduce fat deposition in the body. We used gonadectomized rats fed a high-fat diet to investigate the effects of BCAAs on lipid metabolism over an 8-week experimental period. Body composition, tissue histology, plasma lipid indices, and hormone levels were examined. We demonstrated that the body weights of rats were not significantly decreased but the mesenteric fat was significantly decreased (p < 0.05) in BCAA-treated rats. In addition, BCAAs decreased plasma lipid levels and fat deposition in the liver. At week 4, when the untreated rats displayed macrovesicular steatosis, BCAA-treated rats had only macrovesicular droplets in their hepatocytes. At week 8, when the untreated rat livers displayed profound inflammation and cirrhosis, BCAA-treated rat livers remained in the macrovesicular stage of steatosis. BCAAs induced higher blood glucose and plasma insulin levels (p < 0.05). BCAAs also improved liver blood flow by increasing mean arterial blood pressure and decreasing portal pressure, which helped delay the change in blood flow pattern to that of cirrhosis. BCAAs also induced the skeletal muscle to express higher levels of branched-chain α-keto acid dehydrogenase E1α, which indicates an enhanced metabolic capacity of BCAAs in muscle tissue. This study clearly demonstrates the effects of BCAAs on the amelioration of fat deposition in rats fed a high-fat diet.

Increased intrahepatic resistance in severe steatosis: endothelial dysfunction, vasoconstrictor overproduction and altered microvascular architecture

Non-alcoholic fatty liver disease can progress to steatohepatitis and fibrosis, and is also associated with impaired liver regeneration. The pathophysiology remains elusive. We recently showed that severe steatosis is associated with an increase in portal pressure, suggesting liver flow impairment. The objective of this study is to directly assess total intrahepatic resistance and its potential functional and structural determinants in an in situ perfusion model. Male Wistar rats fed a control (n = 30) or a methionine-choline-deficient (MCD) diet (n = 30) for 4 weeks were compared. Liver tissue and serum analysis, in vivo haemodynamic measurements, in situ perfusion experiments and vascular corrosion casts were performed. The MCD group showed severe steatosis without inflammation or fibrosis on histology. Serum levels and liver tissue gene expression of interleukin (IL)-6, tumour necrosis factor-α, IL-1β and interferon-γ, liver tissue myeloperoxidase activity and liver immunohistochemistry with anti-CD68 and anti-α smooth muscle actin were comparable between groups, excluding significant inflammation. Flow-pressure curves were significantly different between groups for all flows (slope values: 0.1636 ± 0.0605 mm Hg/ml/min in controls vs 0.7270 ± 0.0408 mm Hg/ml/min in MCD-fed rats, P < 0.001), indicating an increased intrahepatic resistance, which was haemodynamically significant (portocaval pressure gradient 2.2 ± 1.1 vs 8.2 ± 1.3 mm Hg in controls vs MCD, P<0.001). Dose-response curves to acetylcholine were significantly reduced in MCD-fed rats (P < 0.001) as was the responsiveness to methoxamine (P<0.001). Vascular corrosion casts showed a replacement of the regular sinusoidal anatomy by a disorganized pattern with multiple interconnections and vascular extensions. Liver phosphorylated endothelial NO synthase (eNOS)/eNOS and serum nitrite/nitrate were not increased in severe steatosis, whereas liver thromboxane synthase expression, liver endothelin-1 (ET-1) expression and serum andothelin-1 concentration were significantly increased. Severe steatosis induces a haemodynamically significant increase in intrahepatic resistance, which precedes inflammation and fibrogenesis. Both functional (endothelial dysfunction and increased thromboxane and ET-1 synthesis) and structural factors are involved. This phenomenon might significantly contribute to steatosis-related disease.

Breath biomarkers of liver cirrhosis

The diagnosis of asymptomatic cirrhosis in patients with liver disease is of importance to start screening for complications in due time. Liver biopsy is neither sensitive nor practical enough to be used as a frequent follow-up test in patients with chronic liver disease. The volatile organic compounds present in exhaled breath offer the possibility of exploring internal physiologic and pathologic process in a non invasive way. This study examined whether a specific pattern of biomarkers can be found in breath samples of patients with cirrhosis. To this aim samples of alveolar breath from patients with cirrhosis and healthy volunteers were analyzed using gas chromatography-mass spectrometry. When linear discriminant analysis was used to search for a model(s)/pattern of compounds characteristic for liver cirrhosis, 24 models of 8 independent compounds could distinguish between the groups. The sensitivity and specificity (between 82% and 88%, and 96% and 100%, respectively) of the models suggest that a specific pattern of breath biomarkers can be found in patients with cirrhosis, which may allow detecting this complication of chronic liver disease in an early stage.

Kidneys in chronic liver diseases

Acute kidney injury (AKI), defined as an abrupt increase in the serum creatinine level by at least 0.3 mg/dL, occurs in about 20% of patients hospitalized for decompensating liver cirrhosis. Patients with cirrhosis are susceptible to developing AKI because of the progressive vasodilatory state, reduced effective blood volume and stimulation of vasoconstrictor hormones. The most common causes of AKI in cirrhosis are pre-renal azotemia, hepatorenal syndrome and acute tubular necrosis. Differential diagnosis is based on analysis of circumstances of AKI development, natriuresis, urine osmolality, response to withdrawal of diuretics and volume repletion, and rarely on renal biopsy. Chronic glomerulonephritis and obstructive uropathy are rare causes of azotemia in cirrhotic patients. AKI is one of the last events in the natural history of chronic liver disease, therefore, such patients should have an expedited referral for liver transplantation. Hepatorenal syndrome (HRS) is initiated by progressive portal hypertension, and may be prematurely triggered by bacterial infections, nonbacterial systemic inflammatory reactions, excessive diuresis, gastrointestinal hemorrhage, diarrhea or nephrotoxic agents. Each type of renal disease has a specific treatment approach ranging from repletion of the vascular system to renal replacement therapy. The treatment of choice in type 1 hepatorenal syndrome is a combination of vasoconstrictor with albumin infusion, which is effective in about 50% of patients. The second-line treatment of HRS involves a transjugular intrahepatic portosystemic shunt, renal vasoprotection or systems of artificial liver support.