Nuclear factor-kappaB inhibition improves myocardial contractility in rats with cirrhotic cardiomyopathy

Cardiac dysfunction in patients with cirrhosis and acute decompensation

The prevalence of cirrhotic cardiomyopathy (CCM) has been reported as high as 60%-70% in patients with liver cirrhosis and is associated with various negative outcomes. There has been a growing understanding of CCM over recent years. Indeed, the development of imaging techniques has enabled new diagnostic criteria to be proposed by the Cirrhotic Cardiomyopathy Consortium. However, important unanswered questions remain over pathophysiological mechanisms, optimal diagnostic modalities and potential treatment options. While there has been an increasing volume of literature evaluating CCM, there is a lack of clarity on its implications in acute decompensation, acute-on-chronic liver failure and following interventions such as transjugular intrahepatic portosystemic shunt insertion and liver transplantation. This review aims to summarise the literature in these challenging domains and suggest where future research should focus. We conclude that systemic inflammation and structural myocardial changes are likely to be crucial in the pathophysiology of the disease, but the relative contribution of different components remains elusive. Furthermore, future studies need to use standardised diagnostic criteria for CCM as well as incorporate newer imaging techniques assessing both myocardial structure and function. Finally, while specific treatments are currently lacking, therapeutics targeting systemic inflammation, microbial dysbiosis and bacterial translocation are promising targets and warrant further research.

Galectin-3 inhibits cardiac contractility via a TNFα-dependent mechanism in cirrhotic rats

Background/Aims

Galectin-3 plays a key pathogenic role in cardiac hypertrophy and heart failure. The present study aimed to investigate the effects of galectin-3 on cardiomyopathy – related factors and cardiac contractility in a rat model of cirrhotic cardiomyopathy.

Methods

Rats were divided into two sets, one for a functional study, the other for cardiac contractile-related protein evaluation. There were four groups in each set: sham operated and sham plus N-acetyllactosamine (N-Lac, a galectin-3 inhibitor; 5 mg/kg); bile duct ligated (BDL) and BDL plus N-Lac. Four weeks after surgery, ventricular level of galectin-3, collagen I and III ratio, tumor necrosis factor alpha (TNFα), and brain natriuretic peptide (BNP) were measured either by Western blots or immunohistochemistry or enzyme-linked immunosorbent assay. Blood pressure was measured by polygraph recorder. Cardiomyocyte contractility was measured by inverted microscopy.

Results

Galectin-3 and collagen I/III ratio were significantly increased in cirrhotic hearts. TNFα and BNP were significantly increased in BDL serum and heart compared with sham controls. Galectin-3 inhibitor significantly decreased galectin-3, TNFα, and BNP in cirrhotic hearts but not in sham controls. N-Lac also significantly improved the blood pressure, and systolic and diastolic cardiomyocyte contractility in cirrhotic rats but had no effect on sham controls.

Conclusion

Increased galectin-3 in the cirrhotic heart significantly inhibited contractility via TNFα. Inhibition of galectin-3 decreased the cardiac content of TNFα and BNP and reversed the decreased blood pressure and depressed contractility in the cirrhotic heart. Galectin-3 appears to play a pathogenic role in cirrhotic cardiomyopathy.

Mechanistic insights into the pathophysiology of cirrhotic cardiomyopathy

Myocardial dysfunction in end stage cirrhotic liver disease, termed cirrhotic cardiomyopathy, is a long known, but little understood comorbidity seen in ∼50% of adults and children who present for liver transplantation. Structural, functional, hemodynamic and electrocardiographic aberrations that occur in the heart as a direct consequence of a damaged liver, is associated with multi-organ failure and increased mortality and morbidity in patients undergoing surgical procedures such as porto-systemic shunt placement and liver transplantation. Despite its clinical significance and rapid advances in science and pharmacotherapy, there is yet no specific treatment for this disease. This may be due to a lack of understanding of the pathogenesis and mechanisms behind how a cirrhotic liver causes cardiac pathology. This review will focus specifically on insights into the molecular mechanisms that drive this liver-heart interaction. Deeper understanding of the etio-pathogenesis of cirrhotic cardiomyopathy will allow us to design and test treatments that can be targeted to prevent and/or reverse this co-morbid consequence of liver failure and improve health care delivery and outcomes in patients with cirrhosis.

Protective Effects of Spermidine Against Cirrhotic Cardiomyopathy in Bile Duct-Ligated Rats

Cirrhotic cardiomyopathy is a critical factor that causes morbidity and mortality in crucial conditions such as liver transplantation. In animal model, the common pathophysiologic mechanisms of cirrhotic cardiomyopathy are similar to those associated with bile duct ligation (BDL). Overproduction of inflammatory and oxidant markers plays a crucial role in cirrhotic cardiomyopathy. Spermidine, a multifunctional polyamine, is known for its antioxidant and anti-inflammatory effects. In this study, we investigated the effects of spermidine on development of cirrhotic cardiomyopathy in BDL rats. Rats were randomly housed in 6 groups. Except the normal and sham groups, BDL was performed for all the control and spermidine groups. Seven days after operation, 3 different doses of spermidine (5, 10 and 50 mg/kg) were administrated until day 28, in spermidine groups. At the end of the fourth week, the electrocardiography (ECG) and papillary muscle isolation were performed. The serum level of tumor necrosis factor-a (TNF-α), interleukin-1β (IL-1β), and IL-10 and cardiac level of superoxide dismutase, glutathione (GSH). and malondialdehyde (MDA) were assessed. Furthermore, the nuclear factor-κB (NF-κB) expression was assessed by western blot. Cardiac histopathological changes were monitored. The serum levels of magnesium (Mg) and potassium (K) were investigated. Control group, exhibited exaggerated signs of cirrhotic cardiomyopathy in comparison with the sham group. Co-administration of spermidine at the dose of 10 mg/kg in BDL rats significantly improved the cardiac condition, reduced the inflammatory mediators, and increased antioxidant enzymes. In addition, the histopathologic findings were in accordance with the other results of the study. Besides, there was no significant alteration in serum levels of Mg and K. This study demonstrates that spermidine at the dose of 10 mg/kg significantly improved the cirrhotic cardiomyopathy in BDL model in rats.

Pgc-1α Promotes Phosphorylation, Inflammation, and Apoptosis in H9c2 Cells During the Early Stage of Lipopolysaccharide Induction

Cardiac dysfunction in severe sepsis is associated with increased mortality. However, the molecular mechanisms underlying septic heart dysfunction remain unclear. Expression of peroxisome proliferator-activated receptor-γ coactivator 1α (Pgc-1α), concentrations of inflammatory factors, and activation of the nuclear factor kappa-B (NF-κB) signaling pathway were examined in H9c2 cells after a 24-h lipopolysaccharide (LPS) stimulation period using qPCR, enzyme-linked immunosorbent assays (ELISAs), and western blots (WBs), respectively. Pgc-1α was overexpressed and suppressed in cells using a lentivirus vector and siRNA, respectively. The effects of Pgc-1α dysfunction on the release of inflammatory factors and apoptosis were analyzed. Pgc-1α expression was increased after LPS induction for 0.5 h and returned to the pre-induction level at 2 h. Levels of IL-1β, IL-6, and TNF-α increase after LPS induction for 0.5 h and accumulated in the culture supernatants over time. The WBs revealed the highest Pgc-1α and phospho (p)-p65 protein levels after LPS induction for 0.5 h, followed by a decrease; moreover, the cleaved-caspase-3 level increased after LPS induction for 0.5 h and increased gradually thereafter. A functional analysis of Pgc-1α revealed that overexpression of this protein enhanced LPS-induced inflammatory factors and p-p65 levels and inhibited apoptosis during the early stage after LPS induction (0.5 and 4 h). In contrast, the inhibition of Pgc-1α expression inhibited the LPS expression-associated increases in inflammatory factors and p-p65 and promoted apoptosis. Pgc-1α promoted LPS-induced p65 phosphorylation and inflammatory factor release while inhibiting apoptosis.

Overview of bile acid signaling in the cardiovascular system

Bile acids (BAs) are classically known to play a vital role in the metabolism of lipids and in absorption. It is now well established that BAs act as signaling molecules, activating different receptors (such as farnesoid X receptor, vitamin D receptor, Takeda G-protein-coupled receptor 5, sphingosine-1-phosphate, muscarinic receptors, and big potassium channels) and participating in the regulation of energy homeostasis and lipid and glucose metabolism. In addition, increased BAs can impair cardiovascular function in liver cirrhosis. Approximately 50% of patients with cirrhosis develop cirrhotic cardiomyopathy. Exposure to high concentrations of hydrophobic BAs has been shown to be related to adverse effects with respect to vascular tension, endothelial function, arrhythmias, coronary atherosclerotic heart disease, and heart failure. The BAs in the serum BA pool have relevant through their hydrophobicity, and the lipophilic BAs are more harmful to the heart. Interestingly, ursodeoxycholic acid is a hydrophilic BA, and it is used as a therapeutic drug to reverse and protect the harmful cardiac effects caused by hydrophobic elevated BAs. In order to elucidate the mechanism of BAs and cardiovascular function, abundant experiments have been conducted in vitro and in vivo. The aim of this review was to explore the mechanism of BAs in the cardiovascular system.

Myocardial Dysfunction in Cirrhotic Cardiomyopathy is Associated with Alterations of Phospholamban Phosphorylation and IL-6 Levels

BACKGROUND

Decreased cardiac contractility has been observed in cirrhosis, but the mechanisms that initiate and maintain cardiac dysfunction are not entirely understood.

AIM OF THE STUDY

We test the hypothesis that cirrhotic cardiomyopathy is related to deterioration of myocardial contractility due to alterations in calcium-handling proteins expression. In addition, we evaluated whether cardiac pro-inflammatory cytokine levels are associated with this process.

METHODS

Cirrhosis was induced by thioacetamide (TAA, 100 mg/kg/i.p., twice weekly for eight weeks). The myocardial performance was evaluated in isolated left ventricle papillary muscles under basal conditions and after inotropic challenge. The cardiac calcium handling protein expression was detected by Western blotting. Cardiac TNF-α and IL-6 levels were measured by ELISA.

RESULTS

Thioacetamide induced liver cirrhosis, which was associated with cirrhotic cardiomyopathy characterized by in vivo left ventricular diastolic and systolic dysfunction as well as cardiac hypertrophy. In vitro baseline myocardial contractility was lower in cirrhosis. Also, myocardial responsiveness to post-rest contraction stimulus was declined. Protein expression for RYR2, SERCA2, NCX, pPBL Ser¹⁶ and L-type calcium channel was quantitatively unchanged; however, pPBL Thr¹⁷ was significantly lower while IL-6 was higher.

CONCLUSIONS

Our study demonstrates that cirrhotic cardiomyopathy is associated with decreased cardiac contractility with alteration of phospholamban phosphorylation in association with higher cardiac pro-inflammatory IL-6 levels. These findings provided molecular and functional insights about the effects of liver cirrhosis on cardiac function.

Role of Oxidative Stress in Hepatic and Extrahepatic Dysfunctions during Nonalcoholic Fatty Liver Disease (NAFLD)

Nonalcoholic fatty liver disease (NAFLD) is a pathology that contains a broad liver dysfunctions spectrum. These alterations span from noninflammatory isolated steatosis until nonalcoholic steatohepatitis (NASH), a more aggressive form of the disease characterized by steatosis, inflammatory status, and varying liver degrees fibrosis. NAFLD is the most prevalent chronic liver disease worldwide. The causes of NAFLD are diverse and include genetic and environmental factors. The presence of NASH is strongly associated with cirrhosis development and hepatocellular carcinoma, two conditions that require liver transplantation. The liver alterations during NAFLD are well described. Interestingly, this pathological condition also affects other critical tissues and organs, such as skeletal muscle and even the cardiovascular, renal, and nervous systems. Oxidative stress (OS) is a harmful state present in several chronic diseases, such as NAFLD. The purpose of this review is to describe hepatic and extrahepatic dysfunctions in NAFLD. We will also review the influence of OS on the physiopathological events that affect the critical function of the liver and peripheral tissues.

Preconception Exposure to Fine Particulate Matter Leads to Cardiac Dysfunction in Adult Male Offspring

Background Particulate matter (particles < 2.5 μm [ PM _2.5]) exposure during the in utero and postnatal developmental periods causes cardiac dysfunction during adulthood. Here, we investigated the potential priming effects of preconception exposure of PM _2.5 on cardiac function in adult offspring. Methods and Results Male and female friend leukemia virus b (FVB) mice were exposed to either filtered air ( FA ) or PM _2.5 at an average concentration of 38.58 μg/m³ for 6 hours/day, 5 days/week for 3 months. Mice were then crossbred into 2 groups: (1)  FA _male× FA _female (both parents were exposed to FA preconception) and, (2) PM _2.5male× PM _2.5female (both parents were exposed to PM _2.5 preconception). Male offspring were divided: (1) preconception FA (offspring born to FA exposed parents) and, (2) preconception PM _2.5 (offspring born to PM _2.5 exposed parents) and analyzed at 3 months of age. Echocardiography identified increased left ventricular end systolic volume and reduced posterior wall thickness, reduced %fractional shortening and %ejection fraction in preconception PM _2.5 offspring. Cardiomyocytes isolated from preconception PM _2.5 offspring showed reduced %peak shortening, -dL/dT, TPS 90 and slower calcium reuptake (tau). Gene and protein expression revealed modifications in markers of inflammation ( IL -6, IL -15, TNF α, NF қB, CRP , CD 26E, CD 26P, intercellular adhesion molecule 1, and monocyte chemoattractant protein-1) profibrosis (collagen type III alpha 1 chain), oxidative stress ( NOS 2), antioxidants (Nrf2, SOD , catalase), Ca²⁺ regulatory proteins ( SERCA 2a, p- PLN , NCX ), and epigenetic regulators (Dnmt1, Dnmt3a, Dnmt3b, Sirt1, and Sirt2) in preconception PM _2.5 offspring. Conclusions Preconception exposure to PM _2.5 results in global cardiac dysfunction in adult offspring, suggesting that abnormalities during development are not limited to the prenatal or postnatal periods but can also be determined before conception.

Severity and properties of cardiac damage caused by Streptococcus pneumoniae are strain dependent

Streptococcus pneumoniae is an opportunistic Gram-positive pathogen that can cause invasive disease. Recent studies have shown that S. pneumoniae is able to invade the myocardium and kill cardiomyocytes, with one-in-five adults hospitalized for pneumococcal pneumonia having a pneumonia-associated adverse cardiac event. Furthermore, clinical reports have shown up to a 10-year increased risk of adverse cardiac events in patients formerly hospitalized for pneumococcal bacteremia. In this study, we investigated the ability of nine S. pneumoniae clinical isolates, representing eight unique serotypes, to cause cardiac damage in a mouse model of invasive disease. Following intraperitoneal challenge of C57BL/6 mice, four of these strains (D39, WU2, TIGR4, and 6A-10) caused high-grade bacteremia, while CDC7F:2617-97 and AMQ16 caused mid- and low-grade bacteremia, respectively. Three strains did not cause any discernible disease. Of note, only the strains capable of high-grade bacteremia caused cardiac damage, as inferred by serum levels of cardiac troponin-I. This link between bacteremia and heart damage was further corroborated by Hematoxylin & Eosin and Trichrome staining which showed cardiac cytotoxicity only in D39, WU2, TIGR4, and 6A-10 infected mice. Finally, hearts infected with these strains showed varying histopathological characteristics, such as differential lesion formation and myocytolysis, suggesting that the mechanism of heart damage varied between strains.

Myocardial extracellular volume quantified by magnetic resonance is increased in cirrhosis and related to poor outcome

BACKGROUND & AIMS

The underlying pathogenesis of cirrhotic cardiomyopathy remains unclear. Structural myocardial changes including diffuse fibrosis may be involved and can be accurately assessed by cardiac MRI (CMR) with quantification of the extracellular volume (ECV).This is the first application of this technique in patients with cirrhosis. We aimed to investigate the presence of diffuse myocardial fibrosis and to determine the relation to disease severity, cardiac function and outcome.

METHODS

A prospective study including 52 cirrhotic patients and 10 healthy controls. All patients underwent CMR with ECV quantification, tissue Doppler echocardiography, and biochemical assessments. Patients were followed up for a median of 25 months with registration of death and liver transplantation (LT).

RESULTS

Myocardial ECV was higher in the patients compared with healthy controls (31.2 ± 6 vs 27.4 ± 3%, P = .04). Furthermore, ECV increased across the Child Pugh A/B/C classes (26.9 ± 4/31.5 ± 5/34.4 ± 6%, P = .02). Four-teen patients experienced the composite end-point of death/LT during follow-up and these patients had higher ECV (33.2 ± 4 vs 30.4 ± 6%, P = .04). In a univariate Cox regression analysis ECV was associated with poor transplant-free survival (HR 3.6 [1.1-11.6]; P = .03). However, MELD and CRP remained the strongest predictors in a multivariate analysis. ECV correlated with cardiac index (r = 0.44, P = .001), CRP (r = 0.46, P = .001), proANP (r = 0.50, P < .001), and proBNP (r = 0.40, P = .005).

CONCLUSIONS

Myocardial ECV is increased in patients with cirrhosis and seems related to disease severity and transplant-free survival. These changes most likely reflect subclinical diffuse myocardial fibrosis and may represent a structural element of cirrhotic cardiomyopathy.

Bile acids and cardiovascular function in cirrhosis

Cirrhotic cardiomyopathy and the hyperdynamic syndrome are clinically important complications of cirrhosis, but their exact pathogenesis is still partly unknown. Experimental models have proven the cardiotoxic effects of bile acids and recent studies of their varied receptor-mediated functions offer new insight into their involvement in cardiovascular dysfunction in cirrhosis. Bile acid receptors such as farnesoid X-activated receptor and TGR5 are currently under investigation as potential therapeutic targets in a variety of pathological conditions. These receptors have also recently been identified in cardiomyocytes, vascular endothelial cells and smooth muscle cells where they seem to play an important role in cellular metabolism. Chronic cholestasis leading to abnormal levels of circulating bile acids alters the normal signalling pathways and contributes to the development of profound cardiovascular disturbances. This review summarizes the evidence regarding the role of bile acids and their receptors in the generation of cardiovascular dysfunction in cirrhosis.

Cardiac involvement in patients with cirrhosis: a focus on clinical features and diagnosis

Cirrhotic heart has been traditionally considered protected from cardiovascular disease, even if a large amount of literature has recently shown that patients affected by chronic liver disease are exposed to cardiovascular events, as well. Since the first recognition of cardiac involvement in cirrhosis, all published studies explain that decompensated cirrhotic patients suffer from haemodynamic changes, currently known as hyperdynamic syndrome, which finally lead to cirrhotic cardiomyopathy. This is defined by the presence of a subclinical systolic dysfunction unmasked under stress conditions, impaired diastolic function and electrophysiological abnormalities, in the absence of any known cardiac disease. In this review, we will discuss the clinical and diagnostic features of this condition, the prevalence of associated comorbidities, echocardiographic, electrocardiographic and cardiac magnetic resonance hallmarks and the possible diagnostic role of serum biomarkers.

Increased Circulating Advanced Oxidation Protein Products and High-Sensitive Troponin T in Cirrhotic Patients with Chronic Hepatitis C: A Preliminary Report

Aim. To investigate the relationship between advanced oxidation protein products (AOPPs) and myocardial injury by comparing the selected biomarker for detecting myocardial injury [high-sensitive troponin T (hs-TnT)] in patients with chronic HCV infection. Methods and Results. Eighty-eight patients with cirrhosis and 40 healthy control subjects were enrolled in the study. Circulating levels of AOPPs-albumin (the ratio of AOPPs to albumin content), hs-TnT, tumor necrosis factor α (TNF-α), and high-sensitivity C-reactive protein (hs-CRP) were assessed. Compared with healthy controls, the cirrhotic patients with chronic HCV infection had higher levels of AOPPs-albumin, which were associated with increased hs-TnT. When the presence of ascites was considered, the plasma levels of AOPPs-albumin were higher, as well as TNF-α. AOPPs-albumin positively correlated with hs-TnT level in all cirrhotic patients with chronic HCV infection and this correlation was stronger in decompensated cirrhotic patients. In multivariate logistic regression analysis, the independent factors associated with the presence of ascites were high AOPPs-albumin levels and elevated hs-TnT levels. Conclusion. The simultaneous monitoring of plasma AOPPs and hs-TnT can be helpful for the alterations in myocardial function control in cirrhotic patients with chronic HCV infection.

Cirrhotic cardiomyopathy

During the course of cirrhosis, there is a progressive deterioration of cardiac function manifested by the disappearance of the hyperdynamic circulation due to a failure in heart function with decreased cardiac output. This is due to a deterioration in inotropic and chronotropic function which takes place in parallel with a diastolic dysfunction and cardiac hypertrophy in the absence of other known cardiac disease. Other findings of this specific cardiomyopathy include impaired contractile responsiveness to stress stimuli and electrophysiological abnormalities with prolonged QT interval. The pathogenic mechanisms of cirrhotic cardiomyopathy include impairment of the b-adrenergic receptor signalling, abnormal cardiomyocyte membrane lipid composition and biophysical properties, ion channel defects and overactivity of humoral cardiodepressant factors. Cirrhotic cardiomyopathy may be difficult to determine due to the lack of a specific diagnosis test. However, an echocardiogram allows the detection of the diastolic dysfunction and the E/e′ ratio may be used in the follow-up progression of the illness. Cirrhotic cardiomyopathy plays an important role in the pathogenesis of the impairment of effective arterial blood volume and correlates with the degree of liver failure. A clinical consequence of cardiac dysfunction is an inadequate cardiac response in the setting of vascular stress that may result in renal hypoperfusion leading to renal failure. The prognosis is difficult to establish but the severity of diastolic dysfunction may be a marker of mortality risk. Treatment is non-specific and liver transplantation may normalize the cardiac function.

Systemic inflammation is associated with increased intrahepatic resistance and mortality in alcohol-related acute-on-chronic liver failure

BACKGROUND & AIMS

Acute-on-chronic liver failure (ACLF) is characterized by acute deterioration of cirrhosis, systemic inflammation and multi-organ failure. Inflammation is also key to the pathobiology of portal hypertension. This study aims to define the relationship between systemic and hepatic haemodynamics in patients with ACLF.

METHODS

Sixty patients with alcoholic cirrhosis were prospectively enrolled - stable cirrhosis (SC, n = 27), acute decompensation without ACLF (AD, n = 14) and ACLF (n = 19) - and managed with standard therapy. Systemic and hepatic haemodynamic studies were performed, and patients were followed up for 3 months. Plasma norepinephrine, cytokine profile, nitrate/nitrite and malondialdehyde levels were measured.

RESULTS

Three-month mortality was as follows: SC - none; AD - 14%; ACLF - 47.2% (P < 0.001). Mean arterial pressure was lowest in the ACLF group (P < 0.001). ACLF patients had significantly higher hepatic vein pressure gradient (HVPG), while the hepatic blood flow was markedly reduced with an increase in intrahepatic resistance, which predicted mortality (AUROC: 0.87, P < 0.0001). In ACLF, the severity of intrahepatic resistance correlated with markers of inflammatory response, norepinephrine levels, creatinine levels and severity of encephalopathy. Modelling data showed that the high norepinephrine levels in ACLF may contribute to the right shift of the HVPG-hepatic blood flow relationship and its levels correlated with inflammatory markers and mortality (AUROC: 0.90; P < 0.0001).

CONCLUSIONS

The disturbances in systemic and hepatic haemodynamics in alcohol-related ACLF are associated with dysregulated inflammation, multi-organ failure and marked activation of the sympathetic nervous system. These abnormalities predict high mortality rates in alcohol-related ACLF patients.

Cardiomyocyte apoptosis contributes to pathogenesis of cirrhotic cardiomyopathy in bile duct-ligated mice

Cirrhotic cardiomyopathy is defined as systolic and diastolic dysfunctions, electrophysiological changes and macroscopic structural changes. However, the underlying mechanisms of this syndrome remain unclear. A possible role of myocardial apoptosis in the pathogenesis has not been previously examined. We hypothesized that dysregulation of apoptotic signalling participates in cardiac dysfunction in the cirrhotic heart. Therefore, we evaluated apoptotic pathways in the hearts of mice with chronic BDL (bile duct ligation). A cirrhotic cardiomyopathy model was induced by BDL in mice. Left ventricular geometry and volumes were evaluated by MRI. Intrinsic and extrinsic apoptotic pathways were evaluated by immunohistochemical staining and Western blot analysis. Fas-mediated apoptosis was inhibited by in vivo administration of an anti-FasL (Fas ligand) monoclonal antibody, and subsequently cardiac contractility was measured in isolated cardiomyocytes. BDL-mice showed significantly more PARP [poly(ADP-ribose) polymerase] staining than sham controls (18.2±11.4 compared with 6.7±5.3; P<0.05). Fas protein expression and PARP cleavage were activated, whereas FLIP (Fas-associated death domain-like interleukin 1β-converting enzyme-inhibitory protein) was decreased compared with sham controls. The Bcl-2/Bax ratio was increased in BDL-mice compared with sham controls. Anti-FasL monoclonal antibody injection in BDL-mice improved systolic and diastolic dysfunctions in cardiomyocytes, but had no effect in sham controls. A net pro-apoptotic balance exists in BDL hearts, mainly mediated by activation of the extrinsic pathway, and abrogation of apoptosis improved contractility. These results suggest that apoptosis contributes to depressed cardiac contractility in a murine model of cirrhotic cardiomyopathy.

The impact of left ventricular hypertrophy on survival in candidates for liver transplantation

Left ventricular hypertrophy (LVH) occurs in 12% to 30% of patients with cirrhosis; however, its prognostic significance is not well studied. We assessed the association of LVH with survival in patients undergoing a liver transplantation (LT) evaluation. We performed a multicenter cohort study of patients undergoing an evaluation for LT. LVH was defined with transthoracic echocardiography. The outcome of interest was all-cause mortality. LVH was present in 138 of 485 patients (28%). Patients with LVH were older, more likely to be male and African American, and were more likely to have hypertension. Three hundred forty-five patients did not undergo transplantation (212 declined, and 133 were waiting): 36 of 110 patients with LVH (33%) died, whereas 57 of 235 patients without LVH (24%) died (P = 0.23). After LT, 8 of 28 patients with LVH (29%) died over the course of 3 years, whereas 9 of 112 patients without LVH (8%) died (P = 0.007). This finding was independent of conventional risk factors for LVH, and all deaths for patients with LVH occurred within 9 months of LT. No clinical or demographic characteristics were associated with mortality among LVH patients. In conclusion, the presence of LVH is associated with an early increase in mortality after LT, and this is independent of conventional risk factors for LVH. Further studies are needed to confirm these findings and identify factors associated with mortality after transplantation to improve outcomes.

Pre-transplant left ventricular diastolic dysfunction is associated with post transplant acute graft rejection and graft failure

INTRODUCTION

Acute cellular rejection (ACR) is a significant cause of morbidity and graft failure in liver transplant recipients (LTR). Diastolic dysfunction (DD) is frequently present in patients with cirrhosis undergoing liver transplantation. However, it is unclear if DD leads to ACR.

METHODS

Data was collected retrospectively for consecutive LTR between January 2000 and December 2010. Demographic data and mortality related data was obtained from social security index. Primary outcome was biopsy proven ACR. Graft failure and all-cause mortality were also evaluated. DD was evaluated as a predictor of these outcomes. Other echocardiographic indices were also assessed as predictors of ACR by using Cox proportional hazard modeling adjusted for covariates.

RESULTS

A total of 970 LTR (mean age 53.2 ± 10 years, women 34.6 % and white 64.5 %) were followed for 5.3 ± 3.4 years. Patients with DD (n = 145, 14.9 %) were significantly more likely to develop ACRs (HR 10.56; 95 % CI 6.78-16.45, p value = 0.0001) as well as graft failure (HR 2.09; 95 % CI 1.22-3.59, p value = 0.007) and all-cause mortality (HR 1.52; 95 % CI 1.08-2.13, p = 0.01). There was an increase in the risk of these outcomes with worsening of DD, when adjusted for various risk factors such as donor and recipient age, gender, race, Framingham risk score, pre-transplant MELD, transplant etiology and cold ischemia time.

CONCLUSION

Pre-transplant DD is significantly associated with increased risk of allograft rejection, graft failure and mortality. This signifies the importance of cardiac evaluation during the pre-transplant period.

Interactions of the heart and the liver

There is a mutual interaction between the function of the heart and the liver and a broad spectrum of acute and chronic entities that affect both the heart and the liver. These can be classified into heart diseases affecting the liver, liver diseases affecting the heart, and conditions affecting the heart and the liver at the same time. In chronic and acute cardiac hepatopathy, owing to cardiac failure, a combination of reduced arterial perfusion and passive congestion leads to cardiac cirrhosis and cardiogenic hypoxic hepatitis. These conditions may impair the liver function and treatment should be directed towards the primary heart disease and seek to secure perfusion of vital organs. In patients with advanced cirrhosis, physical and/or pharmacological stress may reveal a reduced cardiac performance with systolic and diastolic dysfunction and electrophysical abnormalities termed cirrhotic cardiomyopathy. Electrophysiological abnormalities include prolonged QT interval, chronotropic incompetance, and electromechanical uncoupling. No specific therapy can be recommended, but it should be supportive and directed against the heart failure. Numerous conditions affect both the heart and the liver such as infections, inflammatory and systemic diseases, and chronic alcoholism. The risk and prevalence of coronary artery disease are increasing in cirrhotic patients and since the perioperative mortality is high, a careful cardiac evaluation of such patients is required prior to orthotopic liver transplantation.

Positive cardiac inotropic effect of albumin infusion in rodents with cirrhosis and ascites: molecular mechanisms

The aim of this study was to evaluate the effect and molecular mechanism of albumin infusion on cardiac contractility in experimental cirrhosis with ascites. Cardiac contractility was recorded ex vivo in rats with cirrhosis and ascites and in control rats after the injection in the caudal vein of albumin, saline, or hydroxyethyl starch (HES). Gene and protein expression of β-receptors and pathways involved in their intracellular signaling such as Gα(i2) protein (Gα(i2)), adenylate cyclase 3 (Adcy3), protein expression of tumor necrosis factor alpha (TNF-α) and inducible nitric oxide synthase (iNOS), were evaluated in cardiac tissue in both groups. Phosphorylation and membrane-translocation of the cytosolic components of nicotinamide adenine dinucleotide phosphate (NAD(P)H)-oxidase and translocation of nuclear factor kappa B (NF-κB) were also evaluated. After saline intravenous injection, cardiac contractility was significantly reduced in rats with cirrhosis as compared to control rats (P < 0.01). This was associated with: (1) increased expression of protein Gα(i2) (P < 0.05), TNF-α (P < 0.05), iNOS (P < 0.05); (2) increased NAD(P)H-oxidase activity (P < 0.05); (3) increased nuclear translocation of NF-κB (P < 0.05); and (4) lower expression of Adcy 3 (P < 0.05) in cardiac tissue of rats with cirrhosis. After albumin injection cardiac contractility (P < 0.01), protein expression of TNF-α, iNOS, Gα(i2), and Adcy3, NAD(P)H-oxidase activity and nuclear translocation of NF-κB in cardiac tissue of rats with cirrhosis were reversed to control levels (P < 0.05). HES injection did not modify cardiac contractility and nuclear translocation of NF-κB in cardiac tissue of rats with cirrhosis.

CONCLUSION

Albumin exerts a positive cardiac inotropic effect in rats with cirrhosis and ascites counteracting the negative effects of oxidative stress- and TNF-α-induced activation of NF-κB-iNOS pathway and oxidative stress-induced alteration of β-receptor signaling.

Protective effects of erythropoietin on cirrhotic cardiomyopathy in rats

INTRODUCTION

Erythropoietin exerts cardioprotective effects. The present study aimed to investigate the therapeutic effects of erythropoietin on cirrhotic cardiomyopathy.

MATERIALS AND METHODS

Rats were divided into 5 groups: sham control; sham+ erythropoietin; bile duct ligation; bile duct ligation+erythropoietin; bile duct ligation+erythropoietin+anti-tumour necrosis factor alpha (TNFα) antibody and were studied 4 wk after surgery. Erythropoietin was administrated for 10 days before the study date. TNFα, erythropoietin receptor-1 expression and oxidative stress-related parameters were measured. In separate groups, isolated cardiomyocytes were subjected to contractile and relaxation studies. Cardiomyocyte cell line was used to test the direct effect of erythropoietin on nuclear factor (erythroid-derived 2)-like 2(Nrf2).

RESULTS

Erythropoietin receptor-1, TNFα and oxidative modified proteins were significantly increased (p<0.01), and the antioxidant regulator Nrf2 transcription decreased in cirrhotic hearts (p<0.01). Erythropoietin reversed these parameters. Maximal cardiac contractile and relaxation velocity was significantly decreased in cirrhotic cardiomyocytes. Erythropoietin significantly reversed these inhibitions. Anti-TNFα antibody significantly decreased cardiac TNFα content but did not further increase contractility.

CONCLUSIONS

TNFα and oxidative stress are involved in cardiac dysfunction in the cirrhotic heart. Erythropoietin significantly decreased TNFα and oxidative stress and reversed the impaired cardiac function.

Portal hypertensive cardiovascular pathology: the rescue of ancestral survival mechanisms?

The portal system derives from the vitelline system, which is an extra-embryonic venous system. It could be suggested that this extraembryonic origin determines some of the characteristics attributed to portal hypertension, both compensated, i.e. prehepatic, and decompensated, i.e. fibrotic or cirrhotic. The experimental models most frequently used for studying both types of portal hypertension are portal vein ligation and common bile duct ligation in rats, respectively. We propose that in partial portal vein ligated rats, a low-grade inflammatory response, formed by the successive expression of three overlapping phenotypes - ischemia-reperfusion, vitellogenic-like and remodeling or gastrulation-like - is produced. The names of these inflammatory phenotypes developed in compensated portal hypertension are based on some metabolic similarities that can be established with the abovementioned phases of embryonic development. In bile-duct ligated rats, decompensation related to hepatic insufficiency would induce a high-grade inflammatory response. In this experimental model, the splanchnic interstitium, the mesenteric lymph and the peritoneal mesothelium seem to create an inflammatory axis that produces ascites. The functional comparison between the ascitic and the amniotic fluids would imply that, in the decompensated portal hypertensive syndrome, the abdominal mesothelium acquires properties of the amniotic membranes or amnion. In conclusion, the hypothetical comparison between the inflammatory portal hypertensive evolutive types and the evolutive phases of embryonic development could allow for translational research.

Role of cardiac myofilament proteins titin and collagen in the pathogenesis of diastolic dysfunction in cirrhotic rats

BACKGROUND & AIMS

Significance of diastolic dysfunction in cirrhotic cardiomyopathy has been brought to the forefront with several reports of unexpected heart failure following liver transplantation and transjugular intrahepatic portosystemic stent-shunt, but the etiology remains unclear. The present study investigated the role of passive tension regulators - titin and collagen - in the pathogenesis of this condition.

METHODS

Cirrhosis was induced by bile duct ligation (BDL) in rats, while controls underwent bile duct inspection with no ligation. Four weeks after operation, cardiac mRNA and protein levels of titin, collagen, and protein kinase A (PKA) were determined. Diastolic function was examined in isolated right ventricular cardiomyocytes, while passive tension was examined in right ventricular trabeculae muscles.

RESULTS

In BDL animals, diastolic return velocity was significantly decreased, relaxation time increased and passive tension increased. However, no significant difference in mRNA and protein levels of titin was observed. PKA mRNA and protein levels were significantly decreased in BDL animals. Collagen levels were also significantly altered in the BDL group.

CONCLUSIONS

Therefore, diastolic dysfunction exists in cirrhosis with alterations in titin modulation, PKA levels, and collagen configuration contributing to the pathogenesis of this condition.

Cardiac structural and functional alterations in infants and children with biliary atresia, listed for liver transplantation

BACKGROUND & AIMS

Cirrhotic liver diseases are associated with abnormalities in cardiac geometry and function in adults (cirrhotic cardiomyopathy) but rarely explored in cirrhotic infants or children. We proposed that features of cirrhotic cardiomyopathy are present in infants with cirrhosis due to biliary atresia (BA) as early as the time of evaluation for liver transplant and will correlate with mortality and postoperative morbidity.

METHODS

Two-dimensional echocardiography (2DE) of infants with BA (n=40; median age, 8 months), listed for transplantation at the Texas Children's Hospital from 2004 to 2010, were reviewed and compared with age- and sex-matched infants without cardiac or liver disease (controls). Length of stay and correlation with 2DE results were assessed.

RESULTS

Compared with controls, children with BA had significant increases in multiple 2DE parameters, notably left ventricle wall thickness (23% increase), left ventricular (LV) mass indexed to body surface area (51% increase), and LV shortening fraction (8% increase). Overall, features of cirrhotic cardiomyopathy were observed in most infants (29/40; 72%); 17 had hyperdynamic contractility, and 24 had altered LV geometry. After liver transplantation (33), infants with abnormal 2DE results had longer stays in the intensive care unit (median, 6 vs 4 days) and the hospital (21 vs 11 days) compared with infants who had normal 2DE reports. On univariate analysis, the length of hospital stay correlated with LV mass index.

CONCLUSIONS

Cardiomyopathy is a prevalent condition in infants with end-stage cirrhotic liver disease due to BA (>70%). This underrecognized condition likely contributes to the prolongation of posttransplant hospitalization.

Mechanisms of TNFalpha-induced cardiac dysfunction in cholestatic bile duct-ligated mice: interaction between TNFalpha and endocannabinoids

BACKGROUND & AIMS

Chronic liver disease is associated with endotoxemia, oxidative stress, increased endocannabinoids and decreased cardiac responsiveness. Endocannabinoids activate the tumor necrosis factor-alpha (TNFalpha)-nuclear factor kappaB (NFkappaB) pathway. However, how they interact with each other remains obscure. We therefore aimed to clarify the relationship between the TNFalpha-NFkappaB pathway and endocannabinoids in the pathogenesis of cardiodepression of cholestatic bile duct ligated (BDL) mice.

METHODS

BDL mice with TNFalpha knockout (TNFalpha-/-) and infusion of anti-TNFalpha antibody were used. Cardiac mRNA and protein expression of NFkappaBp65, c-Jun-N-terminal kinases (JNK), p38 mitogen-activated protein kinase (p38MAPK), extracelullar-signal- regulated kinase (ERK), inducible nitric oxide synthase (iNOS), Copper/Zinc and Magnesium-superoxide dismutase (Cu/ Zn- and Mn-SOD), cardiac anandamide, 2-arachidonoylglycerol (2-AG), nitric oxide (NOx) and glutathione, and plasma TNFalpha were measured. The effects of TNFalpha, cannabinoid receptor (CB1) antagonist AM251 and the endocannabinoid reuptake inhibitor UCM707, on the contractility of isolated cardiomyocytes, were assessed.

RESULTS

In BDL mice, cardiac mRNA and protein expression of NFkappaBp65, p38MAPK, iNOS, NOx, anandamide, and plasma TNFa were increased, whereas glutathione, Cu/Zn-SOD, and Mn-SOD were decreased. Cardiac contractility was blunted in BDL mice. Anti-TNFa treatment in BDL mice decreased cardiac anandamide and NOx, reduced expression of NFkappaBp65, p38MAPK, and iNOS, enhanced expression of Cu/Zn-SOD and Mn-SOD, increased reductive glutathione and restored cardiomyocyte contractility. TNFa-depressed contractility was worsened by UCM707, whereas AM251 improved contractility.

CONCLUSIONS

Increased TNFalpha, acting via NFkappaB-iNOS and p38MAPK signaling pathways, plays an important role in the pathogenesis of cardiodepression in BDL mice. TNFalpha also suppressed contractility by increasing oxidative stress and endocannabinoid activity.

Cirrhotic cardiomyopathy

Increased cardiac output was first described in patients with cirrhosis more than fifty years ago. Later, various observations have indicated the presence of a latent cardiac dysfunction, which includes a combination of reduced cardiac contractility with systolic and diastolic dysfunction and electrophysiological abnormalities. This syndrome is termed cirrhotic cardiomyopathy. Results of experimental studies indicate the involvement of several mechanisms in the pathophysiology, such as reduced beta-adrenergic receptor signal transduction, altered transmembrane currents and electromechanical coupling, nitric oxide overproduction, and cannabinoid receptor activation. Systolic incompetence in patients can be revealed by pharmacological or physical strain and during stressful procedures, such as transjugular intrahepatic portosystemic shunt insertion and liver transplantation. Systolic dysfunction has recently been implicated in development of renal failure in advanced disease. Diastolic dysfunction reflects delayed left ventricular filling and is partly attributed to ventricular hypertrophy, subendocardial oedema, and altered collagen structure. The QT interval is prolonged in about half of the cirrhotic patients and it may be normalised by beta-blockers. No specific therapy for cirrhotic cardiomyopathy can be recommended, but treatment should be supportive and directed against the cardiac dysfunction. Future research should better describe the prevalence, impact on morbidity and survival, and look for potential treatments.

The heart and the liver

Cardiac failure affects the liver and liver dysfunction affects the heart. Chronic and acute heart failure can lead to cardiac cirrhosis and cardiogenic ischemic hepatitis. These conditions may impair liver function and treatment should be directed towards the primary heart disease and seek to secure perfusion of vital organs. In patients with advanced cirrhosis, physical and/or pharmacological stress may reveal a reduced cardiac performance with systolic and diastolic dysfunction and electrophysical abnormalities, termed cirrhotic cardiomyopathy. Pathophysiological mechanisms include reduced beta-adrenergic receptor signal transduction and defective cardiac electromechanical coupling. However, the QT interval is prolonged in approximately half of patients with cirrhosis and it may be improved by beta-blockers. No specific therapy can be recommended but it should be supportive and directed against the heart failure. Transjugular intrahepatic portosystemic shunt insertion and liver transplantation affect cardiac function in portal hypertensive patients and cause stress to the cirrhotic heart, with a risk of perioperative heart failure. The risk and prevalence of coronary artery disease are increasing in cirrhotic patients and since perioperative mortality is high, careful evaluation of such patients with dobutamine stress echocardiography, coronary angiography and myocardial perfusion imaging is required prior to liver transplantation. Future research should focus on beneficial effects of treatment on cardiac function and mortality.

Cirrhotic cardiomyopathy

Cirrhotic cardiomyopathy is a recently recognized condition in cirrhosis consisting of systolic incompetence under condition of stress, diastolic dysfunction related to altered diastolic relaxation, and electrophysiological abnormalities in the absence of any known cardiac disease. It can be diagnosed by using a combination of electrocardiograph, 2-dimensional echocardiography, and various serum markers such as brain natriuretic factor. The underlying pathogenetic mechanisms include abnormalities in the beta-adrenergic signaling pathway, altered cardiomyocyte membrane fluidity, increased myocardial fibrosis, cardiomyocyte hypertrophy, and ion channel defects. Various compounds for which levels are elevated in cirrhosis such as nitric oxide and carbon monoxide can also exert a negative inotropic effect on the myocardium, whereas excess sodium and volume retention can lead to myocardial hypertrophy. Various toxins can also aggravate the ion channel defects, thereby widening the QRS complex causing prolonged QT intervals. Clinically, systolic incompetence is most evident when cirrhotic patients are placed under stress, whether physical or pharmacological, or when the extent of peripheral arterial vasodilatation demands an increased cardiac output as in the case of bacterial infections. Acute volume overload such as immediately after insertion of a transjugular intrahepatic portosystemic shunt or after liver transplantation can also tip these cirrhotic patients into cardiac failure. Treatment of cirrhotic cardiomyopathy is unsatisfactory. There is some evidence that beta-blockade may help some cirrhotic patients with baseline prolonged QT interval. Long-term aldosterone antagonism may help reduce myocardial hypertrophy. Future studies should include further elucidation of pathogenetic mechanisms so as to develop effective treatment strategies.