Cirrhosis and hepatopulmonary syndrome

Spleen derived monocytes regulate pulmonary vascular permeability in Hepatopulmonary syndrome through the OSM-FGF/FGFR1 signaling

Hepatopulmonary syndrome (HPS) is a serious pulmonary complication in the advanced stage of liver disease. The occurrence of pulmonary edema in HPS patients is life-threatening. Increased pulmonary vascular permeability is an important mechanism leading to pulmonary edema, and endothelial glycocalyx (EG) is a barrier that maintains stable vascular permeability. However, in HPS, whether the pulmonary vascular EG changes and its regulatory mechanism are still unclear. Spleen derived monocytes are involved in the pathogenesis of HPS. However, whether they regulate the pulmonary vascular permeability in HPS patients or rats and what is the mechanism is still unclear. Healthy volunteers and HPS patients with splenectomy or not were enrolled in this study. We found that the respiration of HPS patients was significantly improved in response to splenectomy, while the EG degradation and pulmonary edema were aggravated. In addition, HPS patients expressed higher levels of oncostatin M (OSM) and fibroblast growth factor (FGF). Subsequently, the co-culture system of monocytes and human umbilical vein endothelial cells (HUVECs) was constructed. It was found that monocytes secreted OSM and activated the FGF/FGFR1 signaling pathway in HUVECs. Then, an HPS rat model was constructed by common bile duct ligation (CBDL) for in vivo verification. HPS rats were intravenously injected with OSM recombinant protein and/or TNF-α into the rats via tail vein 30 min before CBDL. The results showed that the respiration of HPS rats was improved after splenectomy, while the degradation of EG in pulmonary vessels and vascular permeability were increased, and pulmonary edema was aggravated. Moreover, the expression of OSM and FGF was upregulated in HPS rats, while both were downregulated after splenectomy. Intravenous injection of exogenous OSM eliminated the effect of splenectomy on FGF and improved EG degradation. It can be seen that during HPS, spleen-derived monocytes secrete OSM to promote pulmonary vascular EG remodeling by activating the FGF/FGFR1 pathway, thereby maintaining stable vascular permeability, and diminishing pulmonary edema. This study provides a promising therapeutic target for the treatment of HPS.

Liver cirrhosis and complications from the perspective of dysbiosis

The gut-liver axis refers to the intimate relationship and rigorous interaction between the gut and the liver. The intestinal barrier's integrity is critical for maintaining liver homeostasis. The liver operates as a second firewall in this interaction, limiting the movement of potentially dangerous compounds from the gut and, as a result, contributing in barrier management. An increasing amount of evidence shows that increased intestinal permeability and subsequent bacterial translocation play a role in liver damage development. The major pathogenic causes in cirrhotic individuals include poor intestinal permeability, nutrition, and intestinal flora dysbiosis. Portal hypertension promotes intestinal permeability and bacterial translocation in advanced liver disease, increasing liver damage. Bacterial dysbiosis is closely related to the development of cirrhosis and its related complications. This article describes the potential mechanisms of dysbiosis in liver cirrhosis and related complications, such as spontaneous bacterial peritonitis, hepatorenal syndrome, portal vein thrombosis, hepatic encephalopathy, and hepatocellular carcinoma, using dysbiosis of the intestinal flora as an entry point.

The importance of and difficulties involved in creating molecular probes for a carbon monoxide gasotransmitter

As one of the triumvirate of recognized gasotransmitter molecules, namely NO, H2S, and CO, the physiological effects of CO and its potential as a biomarker have been widely investigated, garnering particular attention due to its reported hypotensive, anti-inflammatory, and cytoprotective properties, making it a promising therapeutic agent. However, the development of CO molecular probes has remained relatively stagnant in comparison with the fluorescent probes for NO and H2S, owing to its inert molecular state under physiological conditions. In this review, starting from elucidating the definition and significance of CO as a gasotransmitter, the imperative for the advancement of CO probes, especially fluorescent probes, is expounded. Subsequently, the current state of development of CO probe methodologies is comprehensively reviewed, with an overview of the challenges and prospects in this burgeoning field of research.

The effects of N-acetylcysteine on hepatic, hematologic, and renal parameters in cirrhotic patients: a randomized controlled trial

Aim

To evaluate the effects of N-acetylcysteine (NAC) supplementation in cirrhotic patients.

Background

Chronic hepatic inflammation leads to fibrosis and cirrhosis through various mechanisms such as oxidative stress. NAC is one of the intracellular precursors of glutathione that can degrade most reactive oxygen species. Recently, the beneficial effects of NAC in animal and human studies on preventing liver injury progression and improving liver function have been examined. However, more studies on human subjects are still required.

Methods

Well-known cirrhotic patients with a specific etiology and aged 18 to 70 years who referred to the gastrointestinal clinic of Ayatollah Taleghani Hospital from December 2018 to December 2019 were enrolled in the present randomized double-blind controlled trial. Patients in the intervention group received NAC tablets at a dose of 600 mg daily, and the control group received a placebo. Demographic data, medical characteristics, and Child-Pugh and MELD scores evaluated at baseline and after 6 months.

Results

Totally, 60 patients completed the present study (30 patients in the intervention group, and 30 patients in the control group). Hematological and biochemical parameters were normal in both groups with no significant differences at baseline and 6 months after intervention values. Moreover, the renal function indicators including serum creatinine (Cr) and urea (BUN) decreased significantly after intervention. Hepatic parameters also decreased significantly 6 months after intervention. Decreases in the renal and hepatic parameters 6 months after baseline in the control group were not statistically significant.

Conclusion

The results of this study showed that NAC improved hepatic and renal function by decreasing serum urea and creatinine levels but had no significant effect on hematological and biochemical parameters. Furthermore, NAC significantly improved hepatic profiles by decreasing ALT, AST, and ALP in the liver enzymes between the intervention and control groups. Moreover, NAC caused a significant decrease in Child-Pugh and MELD scores.

Consensus on the management of complications of cirrhosis of the liver in pediatrics

The Asociación Mexicana de Hepatología A.C. carried out the Consensus on the Management of Complications of Cirrhosis of the Liver in Pediatrics to provide physicians with useful information for treating said complications. A group of pediatric gastroenterologists and experts in nutrition, nephrology, and infectious diseases participated and reviewed the medical literature. The Delphi method was applied to obtain the level of agreement on the statements that were formulated. The statements were sent to the participants to be analyzed and voted upon, after which they were discussed in virtual sessions, and the final versions were produced. The aim of the consensus results was to issue indications for the management of pediatric patients with liver cirrhosis, to prevent or control complications.

Overview of Complications in Cirrhosis

BACKGROUND

Cirrhosis is the outcome of chronic liver disease of any etiology due to progressive liver injury and fibrosis. Consequently, cirrhosis leads to portal hypertension and liver dysfunction, progressing to complications like ascites, variceal bleeding, hepatic encephalopathy, hepatorenal syndrome, hepatopulmonary syndrome, cirrhotic cardiomyopathy, sarcopenia, hepatocellular carcinoma, and coagulation disorders. End-stage liver disease leads to an impaired quality of life, loss of social and economic productivity, and reduced survival.

METHODS

This narrative review explains the pathophysiology of complications of cirrhosis, the diagnostic approach and innovative management, with focus on data from India. A comprehensive literature search of the published data was performed in regard with the spectrum, diagnosis, and management of cirrhosis and its complications.

RESULTS

There is a change in the epidemiology of metabolic syndrome, lifestyle diseases, alcohol consumption and the spectrum of etiological diagnosis in patients with cirrhosis. With the advent of universal vaccination and efficacious long-term viral suppression agents for chronic hepatitis B, availability of direct-acting antiviral agents for chronic hepatitis C, and a booming liver transplantation programme across the country, the management of complications is essential. There are several updates in the standard of care in the management of complications of cirrhosis, such as hepatorenal syndrome, hepatocellular carcinoma, and hepatic encephalopathy, and new therapies that address supportive and palliative care in advanced cirrhosis.

CONCLUSION

Prevention, early diagnosis, appropriate management of complications, timely transplantation are cornerstones in the management protocol of cirrhosis and portal hypertension. India needs improved access to care, outreach of public health programmes for viral hepatitis care, health infrastructure, and disease registries for improved healthcare outcomes. Low-cost initiatives like immunization, alcohol cessation, awareness about liver diseases, viral hepatitis elimination, and patient focused decision-making algorithms are essential to manage liver disease in India.

Impact of Liver Transplantation on Carbon Monoxide Production as Measured by Arterial Carboxyhemoglobin Levels in Cirrhotic Patients with and without Hepatopulmonary Syndrome

BACKGROUND Hepatic dysfunction is associated with increased production of carbon monoxide. End-stage liver disease patients with hepatopulmonary syndrome (HPS) have been shown to have higher blood carbon monoxide levels than those without HPS. The impact of liver transplantation on blood carbon monoxide levels is currently unknown. We assessed the impact of liver transplantation on blood carbon monoxide and whether this is affected by HPS. MATERIAL AND METHODS Eligible liver transplant recipients had room air arterial blood gas testing performed before and after liver transplantation. The carboxyhemoglobin fraction was obtained from arterial co-oximetry and used as a surrogate for carboxyhemoglobin production. Mean arterial carboxyhemoglobin fraction before transplantation was compared to that after transplantation. Mean absolute and median relative pre- to post-transplant within-patient change in carboxyhemoglobin fraction was compared between those with and without HPS. RESULTS Thirty-nine transplanted cirrhotic patients were analyzed, of whom 14 (36%) met criteria for hepatopulmonary syndrome. The mean pre-transplant carboxyhemoglobin fraction was higher than the post-transplant fraction (2.6 vs 1.8, difference 0.8 [95% CI 0.4-1.2]; P value 0.0002). Of the 14 patients with HPS, 11 (79%) experienced a decrease in their carboxyhemoglobin fraction after liver transplantation; among the 25 patients without HPS, 16 (64%) experienced such a decrease (P=0.48). Neither the absolute nor relative within-patient pre- to post-transplant change in carboxyhemoglobin fraction was significantly different between patients with and without HPS. CONCLUSIONS Blood carbon monoxide levels decreased significantly in cirrhotic patients following liver transplantation, but HPS did not affect the magnitude of this change.

Portal Venous Flow Is Increased by Jejunal but Not Colonic Hydrogen Sulfide in a Nitric Oxide-Dependent Fashion in Rats

Hydrogen sulfide (H2S) is a recently discerned endogenous signaling molecule that modulates the vascular system. Endogenous hydrogen sulfide has been shown to dilate both the mesenteric and portal vasculature. Gut microbiome, via sulfur reducing bacteria, is another source of H2S production within the gut lumen; this source of H2S is primarily produced and detoxified in the colon under physiologic conditions. Nitric oxide (NO), a major endogenous vasodilator in the portal circulation, participates in H2S-induced vasodilation in some vascular beds. We hypothesize that jejunal but not colonic H2S increases portal vein flow in a NO-dependent fashion. To evaluate the effects of luminal H2S, venous blood flow, portal venous pressure, and systemic venous pressure were measured in rats after administration of either vehicle or an H2S donor (NaHS) into the jejunum or the colon. We found that portal venous pressure and systemic pressure did not change and were similar between the three study groups. However, portal venous blood flow significantly increased following jejunal administration of NaHS but not in response to colonic NaHS or vehicle administration. To test the contribution of NO production to this response, another group of animals was treated with either an NO synthase inhibitor (N-Ω-nitro-L-arginine, L-NNA) or saline prior to jejunal NaHS infusion. After L-NNA pretreatment, NaHS caused a significant fall rather than increase in portal venous flow compared to saline pretreatment. These data demonstrate that H2S within the small intestine significantly increases portal venous blood flow in a NO-dependent fashion.

When common things aren't so common: A case report of hepatopulmonary syndrome

A 60-year-old smoker with a history of liver cirrhosis and chronic obstructive pulmonary syndrome (COPD) presented with hypoxic respiratory failure. This was felt secondary to an exacerbation of COPD. Despite treatment, the patient required 10 L of oxygen to achieve saturations of 88% on ambulation. Interstitial lung disease, pulmonary emboli and pulmonary hypertension were excluded as potential aetiologies of hypoxia. Given the history of cirrhosis, hepatopulmonary syndrome was postulated. Contrast echocardiography suggested an extracardiac shunt; a technetium-99m macroaggregated albumin scan confirmed the diagnosis.

Pediatric liver transplantation in severe hepatopulmonary syndrome and use of inhaled nitric oxide for post-transplant hypoxemia-a single center experience

Data on pediatric patients with HPS undergoing LT are limited. Our aim was to study the spectrum and outcomes of pediatric patients with HPS undergoing LDLT. The role ofiNO for post-LDLT refractory hypoxemia was also assessed. Patients (aged < 18 years) undergoing LT were retrospectively studied. HPS was diagnosed based on European Respiratory Society Taskforce 2004 criteria. HPS was graded based on oxygenation criteria and contrast-enhanced echocardiogram. Post-operative course was studied. Refractory post-operative hypoxemia was treated with iNO by institutionally developed protocol. 23/150 pediatric patients undergoing LDLT had HPS. BA was the most common underlying cause (52.2%). By oxygenation criteria, 6 (26.1%) had VS-HPS. VS-HPS was associated with longer LOS (p = .031) and prolonged oxygen requirement (p = .001) compared with other HPS patients. 4/6 patients with VS-HPS had pO2 < 45 mm Hg. Among these, 2 developed ICH post-operatively and 1 died. 3 developed refractory post-operative hypoxemia, successfully treated with iNO. Mean duration of iNO was 26.3 days. In the group of patients with HPS, the incidence of HAT and portal vein thrombosis was 17.3% and 4.3%, respectively. One year post-LDLT survival of patients with HPS was similar to non-HPS patients (86.9% vs 94.4%; p = .88). We concluded that, pediatric patients with VS-HPS, especially those with pre-operative pO2 < 45 mm Hg, have long and difficult post-LT course. Refractory postoperative hypoxemia can be successfully overcome with strategic use of iNO. Vigilant monitoring and good intensive care support are essential.

Pulmonary Complications in Candidates for Liver Transplantation

The liver plays a pivotal role in maintaining the homeostasis of various organ systems. Also, end-stage liver disease and its complications are major causes of morbidity and mortality among adults. Individuals who develop a chronic liver disease are at increased risk of progression to multi-organ dysfunction, including the pulmonary system. The clinical complications of pulmonary problems related to the presence of liver disease range from mild (such as hypoxemia) to life-threatening diseases (such as portopulmonary hypertension and hepatopulmonary syndrome). Herein, the major pulmonary complications related to liver cirrhosis and considerations for performing liver transplantation are reviewed.

Impact of liver damage on blood-borne variables and pulmonary hemodynamic responses to hypoxia and hyperoxia in anesthetized rats

BACKGROUND

Liver disorders may be associated with normal pulmonary hemodynamic, hepatopulmonary syndrome (HPS), or portopulmonary hypertension (POPH). In this study, we aimed to investigate the effect of the severity of liver dysfunctions on blood-borne variables, and pulmonary hemodynamic during repeated ventilation with hyperoxic and hypoxic gases.

METHODS

Female Sprague Dawley rats were assigned into four groups of Sham (n = 7), portal vein ligation (PPVL, n = 7), common bile duct ligation (CBDL, n = 7), and combination of them (CBDL+ PPVL, n = 7). Twenty-eight days later, right ventricular systolic pressure (RVSP) and systemic blood pressure were recorded in anesthetized animals subjected to repeated maneuvers of hyperoxia (O₂ 50%) and hypoxia (O₂ 10%). Besides, we assessed blood parameters and liver histology.

RESULTS

Liver histology score, liver enzymes, WBC and plasma malondialdehyde in the CBDL+PPVL group were higher than those in the CBDL group. Also, the plasma platelet level in the CBDL+PPVL group was lower than those in the other groups. On the other hand, the serum estradiol in the CBDL group was higher than that in the CBDL+PPVL group. All the above parameters in the PPVL group were similar to those in the Sham group. During ventilation with hyperoxia gas, RVSP in the CBDL+PPVL group was higher than the ones in the other groups, and in the CBDL group, it was more than those in the PPVL and Sham groups. Hypoxic pulmonary vasoconstriction (HPV) was not detected in both CBDL+PPVL and CBDL groups, whereas, it retained in the PPVL group.

CONCLUSION

Severe liver damage increases RVSP in the CBDL+PPVL group linked to the high level of ROS, low levels of serum estradiol and platelets or a combination of them. Furthermore, the high RVSP at the noted group could present a reliable animal model for POPH in female rats.

The Effects of Liver Disease on Surgical Outcomes Following Adult Spinal Deformity Surgery

BACKGROUND

As the prevalence of chronic liver disease continues to rise in the United States, understanding the effects of liver dysfunction on surgical outcomes has become increasingly important. The objective of this study was to assess the effects of chronic liver disease on 30-day complications following adult spinal deformity (ASD) surgery.

METHODS

We performed a retrospective cohort study of 2337 patients in the 2008-2015 American College of Surgeons National Surgical Quality Improvement Program database who underwent corrective ASD surgery. Patients with liver disease were identified based on a Model for End-Stage Liver Disease-Na score ≥10. A univariate analysis was performed to compare 30-day postoperative complications between patients with and without liver disease. A multivariate regression analysis adjusting for differences in baseline patient characteristics was performed to identify complications that were associated with liver disease.

RESULTS

Patients with liver disease had a significantly greater incidence of postoperative pulmonary complications (6.3% vs. 2.9%; P < 0.001), blood transfusion (34.6% vs. 24.0%; P < 0.001), sepsis (2.2% vs. 0.9%; P = 0.011), prolonged hospitalization (19.0% vs. 8.0%; P < 0.001), as well as any 30-day complication (45.4% vs. 29.4%; P < 0.001). The multivariate regression analysis identified liver disease as a risk factor for prolonged hospitalization (odds ratio [OR] 2.16; 95% confidence interval [CI] 1.64-2.84; P < 0.001), pulmonary complications (OR 1.78; 95% CI 1.16-2.74; P = 0.009), blood transfusion (OR 1.67; 95% CI 1.36-2.05; P < 0.001), and any 30-day complication (OR 1.43; 95% CI 1.15-1.77; P = 0.001).

CONCLUSIONS

The multisystem pathophysiology of liver dysfunction predisposes patients to postoperative complications following ASD surgery. A multidisciplinary approach in surgical planning and preoperative optimization is needed to minimize liver disease-related complications and improve patient outcomes.

Vascular syndromes in liver cirrhosis

Liver cirrhosis is associated with multiple vascular syndromes affecting almost all body systems. Many of these syndromes are directly related to impaired liver function and sometimes reversible after liver transplantation while others arise secondary to portal hypertension and ascites. Altered expression of angiogenic and vasoactive compounds (most importantly nitric oxide), endothelial dysfunction, dysregulated neurohormonal control, and systemic inflammatory state play differential roles in mediating homeostatic instability and abnormal vasogenic response. Important vascular features encountered in liver disease include portal hypertension, splanchnic overflow, abnormal angiogenesis and shunts, portopulmonary syndrome, hepatopulmonary syndrome, and systemic hyperdynamic circulation. Redistribution of effective circulatory volume deviating from vital organs and pooling in splanchnic circulation is also encountered in liver patients which may lead to devastating outcomes as hepatorenal syndrome. Etiologically, vascular syndromes are not isolated phenomena and vascular dysfunction in one system may lead to the development of another in a different system. This review focuses on understanding the pathophysiological factors underlying vascular syndromes related to chronic liver disease and the potential links among them. Many of these syndromes are associated with high mortality, thus it is crucial to look for early biomarkers for these syndromes and develop novel preventive and therapeutic strategies.

Cyclooxygenase-2 regulates HPS patient serum induced-directional collective HPMVEC migration via PKC/Rac signaling pathway

Hepatopulmonary syndrome (HPS) is a serious complication in patients with advanced liver disease. The pathological pulmonary angiogenesis contributes to the progression of HPS. Importantly, directional collective migration of endothelial cells is a critical event for pathological angiogenesis. Previously, we have demonstrated that the over-expression of Cyclooxygenase-2 (COX-2) was an important factor in the experimental HPS. However, the role of COX-2 in the directional collective migration of human pulmonary microvascular endothelial cells (HPMVECs) is unclear. Our study aims to evaluate the potential effect of COX-2 in the directional collective migration of HPMVECs under the stimulation of HPS patient serum. In this study, 9 patients with stable liver cirrhosis were screened for presence of HPS. We confirmed that HPS patient serum dramatically promoted the directional collective migration and angiogenesis of HPMVECs, while the COX-2 selective antagonist parecoxib significantly inhibited the directional collective migration of HPMVEC under the stimulation of HPS patient serum. In addition, HPS patient serum significantly upregulated the phosphorylation of PKC and promoted the activation of Rac via COX-2/PGE2 signaling pathway. Notably, silencing PKC activation attenuated the directional collective migration of HPMVEC induced by HPS patient serum. In conclusion, these results indicate that PKC/Rac signaling induced by COX-2 modulates collective directional migration of HPMVEC during pathological pulmonary angiogenesis in HPS patients.

Prevalence and characteristics of hepatopulmonary syndrome in children with cirrhosis in southern Brazil

BACKGROUND

Hepatopulmonary syndrome (HPS) is defined as a triad characterized by arterial deoxygenation, intrapulmonary vascular dilatations (IPVDs), and liver disorder. The aims of this study were to assess the prevalence of HPS in children with cirrhosis, the clinical characteristics of patients with HPS, and the tests used for the diagnosis of IPVD.

PATIENTS AND METHODS

This was a prospective, cross-sectional study of 40 children with cirrhosis (median age: 44 months). Investigations of HPS included arterial blood gas analysis, contrast-enhanced transthoracic echocardiography (CE-TTE), and perfusion lung scanning using technetium-99m-labeled macroaggregated albumin (Tc-MMA). Patients' clinical characteristics (age, etiology of cirrhosis, and severity of hepatopathy) were assessed. HPS was defined as liver disease; alveolar-arterial oxygen gradient of at least 15 mmHg and/or partial pressure of arterial oxygen less than 80 mmHg; and detection of IPVD by CE-TTE or Tc-MMA scanning. Statistical significance was indicated by a P value less than 0.05.

RESULTS

The prevalence of HPS was 42.5% (17/40). Eight patients had moderate HPS (47%) and two patients had severe HPS (12%). In bivariate analysis, biliary atresia (P=0.033) and median age (10 months; P=0.005) were associated with HPS. In multivariate analysis, only age remained statistically significant (prevalence ratio=0.99; 95% confidence interval=0.98-0.99; P=0.010). Sixteen patients with HPS had IPVD detected by CE-TTE (94.1%) and six patients had IPVD detected by Tc-MMA scanning (35.3%), with no significant agreement between these methods (κ=-0.12; P=0.163).

CONCLUSION

HPS is a common complication of cirrhosis in children. A combination of clinical and imaging criteria should be used to diagnose HPS.

Screening for Hepatopulmonary Syndrome in Cirrhotic Patients Using Technetium 99m-macroaggregated Albumin Perfusion Lung Scan (Tc-MAA): Diagnostic Approach and Clinical Correlations

BACKGROUND AND AIMS

The aims of this study were to prospectively screen cirrhotic patients with arterial blood gas test and albumin perfusion scan, identify those fulfilling the classic hepatopulmonary syndrome (HPS) criteria, correlate with clinical parameters, and evaluate the survival of patients with HPS compared with those without HPS in a genetically homogenous Cretan cirrhotic population.

MATERIALS AND METHODS

Data on consecutive 102 patients within 1 year were collected and analyzed. All patients underwent a technetium 99m-macroaggregated albumin perfusion lung scan (Tc-MAA). Diagnosis of HPS was based on the presence of the quantitative index Tc-MAA≥6% and a [P(A-a)O2]≥15 mm Hg (≥20 mm Hg for patients over >64 y).

RESULTS

In 94/102 patients, complete scintigraphic data were available. In total, 24 (26%) patients fulfilled the diagnostic criteria of HPS; 95.8% of them had mild-to-moderate HPS. In 8 patients the Tc-MAA scintigraphy could not be interpreted. There was no difference in HPS between decompensated (24.6%) and compensated cirrhosis (27.3%). In the multivariate analysis only the quantitative index was significant for the diagnosis of HPS (P=0.001, odds ratio; 95% confidence interval, 7.05; 2.27-21.87). Kaplan- Meier survival curves indicated a similar overall prognosis for patients diagnosed with HPS (P=0.105).

CONCLUSIONS

HPS is a frequent complication of cirrhosis. Mild-to-moderate HPS has no significant effect on survival of cirrhotic patients. The quantitative Tc-MAA test is a reliable tool for diagnosis.

Rifaximin has the potential to prevent complications of cirrhosis

BACKGROUND

Cirrhosis-related complications are associated with poor prognosis. With our analyses, we examined the potential benefit of rifaximin in reducing the risk of developing cirrhosis-related complications.

METHODS

Adults with cirrhosis and hepatic encephalopathy (HE) in remission were randomly assigned to receive rifaximin 550 mg twice daily or placebo for 6 months with concomitant lactulose permitted. Post hoc analyses examined time to cirrhosis-related complications (HE, spontaneous bacterial peritonitis (SBP), variceal bleeding, acute kidney injury/hepatorenal syndrome). Subgroup analyses evaluated efficacy for select baseline disease characteristics.

RESULTS

Of patients receiving rifaximin (n = 140) and placebo (n = 159), 53.6% and 49.1%, respectively, had baseline Model for End-Stage Liver Disease (MELD) score ⩾ 12 and international normalized ratio (INR) ⩾ 1.2. Baseline ascites was observed in 36.4% (rifaximin) and 34.6% (placebo) of patients. In patients with MELD score ⩾ 12 and INR ⩾ 1.2, rifaximin reduced the relative risk (RR) of any first complication experienced during trial by 59% [hazard ratio (HR) = 0.41, 95% confidence interval (CI): 0.25-0.67; p < 0.001] versus placebo. For patients with baseline ascites, rifaximin reduced the RR of any first complication experienced during trial by 42% versus placebo (HR = 0.58, 95% CI: 0.34-1.0; p = 0.045). For some subgroups, there was a decrease in RR of complications of SBP, variceal bleeding, and acute kidney injury/hepatorenal syndrome with rifaximin versus placebo, although there were few events reported in the study.

CONCLUSION

Rifaximin may reduce the incidence of cirrhosis-related complications and the recurrence of overt HE.[ClinicalTrials.gov identifier: NCT00298038.].

Impact of Bacterial Translocation on Hepatopulmonary Syndrome: A Prospective Observational Study

BACKGROUND/AIMS

Hepatopulmonary syndrome (HPS) is characterized by a defect in oxygenation induced by pulmonary vascular dilatation in cirrhosis. While severe HPS is responsible for a high rate of mortality, the prevalence and pathophysiology of HPS are not fully elucidated. We evaluated the prevalence and pathophysiology of HPS in patients with cirrhosis.

METHODS

A total of 142 patients with cirrhosis who underwent saline-agitated contrast echocardiography were enrolled in this prospective observational study. HPS was defined by positive findings on contrast echocardiography, cirrhosis, and the presence of an oxygenation defect (alveolar-arterial oxygen gradient > 15 mmHg). HPS grades from 0 to 3 were assigned based on the density and spatial distribution of microbubbles in the left ventricle. The primary endpoint was the prevalence of HPS. The secondary endpoints included clinical characteristics and levels of lipopolysaccharide (LPS), LPS-binding protein (LBP), nitric oxide, and endothelin-1 in HPS.

RESULTS

Fifty-nine patients (41.5%) were diagnosed with HPS (grade 1: 24, grade 2: 23, and grade 3: 12 patients). The mean levels of LPS (0.36 ± 0.02, 1.02 ± 0.18, 2.86 ± 0.77, and 6.56 ± 1.46 EU/mL, p < 0.001) and LBP (7026 ± 3336, 11,445 ± 1247, 11,947 ± 1164, and 13,791 ± 2032 ng/mL, p = 0.045) were found to be increased according to HPS grade (negative, grade 1-3). Endothelin-1 levels were significantly elevated according to HPS grade (1.83 ± 0.17, 2.62 ± 0.22, 3.69 ± 0.28, and 4.29 ± 0.34 pg/mL, p < 0.001), demonstrating a significant difference between each grade (p < 0.05).

CONCLUSIONS

HPS is a common complication with a prevalence of 41.5% in patients with cirrhosis. Bacterial translocation and portal pulmonary vascular dilatation are key mechanism involved in the progression of HPS.

Hepatopulmonary Syndrome and Portopulmonary Hypertension: Implications for Liver Transplantation

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH) represent serious pulmonary complications of advanced liver diseases. Orthotopic liver transplantation (OLT) is capable of completely resolving the underlying abnormalities associated with HPS. On the other hand, post-OLT response in patients with PoPH is less predictable, although heavily influenced by pre-OLT mean pulmonary arterial pressure. It remains the case that the opportunity to reverse 2 potentially fatal organ dysfunctions in the liver and the lung make HPS and PoPH more than worthy for further clinical investigations.

Unexplained cyanosis caused by hepatopulmonary syndrome in a girl with APECED syndrome

Autoimmune polyendocrinopathy, candidiasis and ectodermal dystrophy (APECED) is a rare but devastating primary immunodeficiency disease caused by loss-of-function mutations in autoimmune regulator (AIRE) gene on chromosome 21q22.3. The clinical spectrum of the disease is characterized by a wide heterogeneity because of autoimmune reactions toward different endocrine and non-endocrine organs. Here, we report a 17-year-old Turkish girl diagnosed with APECED at 9 years in whom a novel homozygote mutation in AIRE gene p.R15H (c.44G>A) was found. In the clinical course of the patient, chronic liver disease due to autoimmune hepatitis has evolved resulting in hepatopulmonary syndrome (HPS) which has not been reported before in patients with APECED.

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.

Hepatopulmonary syndrome: What we know and what we would like to know

Hepatopulmonary syndrome (HPS) is characterized by abnormalities in blood oxygenation caused by the presence of intrapulmonary vascular dilations (IPVD) in the context of liver disease, generally at a cirrhotic stage. Knowledge about the subject is still only partial. The majority of the information about the etiopathogenesis of HPS has been obtained through experiments on animals. Reported prevalence in patients who are candidates for a liver transplantation (LT) varies between 4% and 32%, with a predominance of mild or moderate cases. Although it is generally asymptomatic it does have an impact on their quality of life and survival. The diagnosis requires taking an arterial blood gas sample of a seated patient with alveolar-arterial oxygen gradient (AaO₂) ≥ 15 mm Hg, or ≥ 20 mm Hg in those over 64 years of age. The IPVD are identified through a transthoracic contrast echocardiography or a macroaggregated albumin lung perfusion scan (^99mTc-MAA). There is currently no effective medical treatment. LT has been shown to reverse the syndrome and improve survival rates, even in severe cases. Therefore the policy of prioritizing LT would appear to increase survival rates. This paper takes a critical and clinical look at the current understanding of HPS, as well as the controversies surrounding it and possible future research.

Nitric oxide metabolites, nitrative stress, and paraoxonase activity in hepatopulmonary syndrome

AIM

To investigate possible abnormalities of vasoactive compounds, nitrative stress, and antioxidant activity of paraoxonase (PONa) in human hepatopulmonary syndrome (HPS), we determined endothelin-1 (ET), nitric oxide (NOx) metabolites, PONa alongside crude plasma nitrotyrosine (NT) as surrogate marker of nitrative stress.

MATERIAL AND METHODS

Liver cirrhosis (LC) patients with HPS (n = 12) were matched by age, sex, and Child-Pugh score to LC patients without HPS (n = 15) and to healthy controls (CTR) (n = 15); plasma NO2(-) (nitrite) (vascular metabolite), NO3(-) (nitrate) (inflammatory metabolite), and PONa were determined by a colorimetric assay, ET, and NT by immunoassays.

RESULTS

HPS patients showed higher level of ET (p = 0.0002), NO2(-) (p = 0.002), NO3(-) (p = 0.0001), NT (p < 0.0001), and lower PONa (p = 0.0004) than CTR; post-hoc analysis revealed greater ET (p < 0.05) and NO3(-) (p < 0.005) in LC patients with HPS than in LC patients without HPS. NT correlated to Child-Pugh score within HPS (p = 0.04) and LC (p = 0.02).

CONCLUSION

Our HPS patients are characterized by elevated plasma levels of ET and NOx metabolites and lower PONa. Reduced PONa alongside elevated NO3(-) and NT suggests that defective antioxidation may favor nitrative stress and both may be implicated in the pathogenesis of HPS.

Long-term survival with growth hormone replacement after liver transplantation of pediatric nonalcoholic steatohepatitis complicating acquired hypopituitarism

Nonalcoholic steatohepatitis (NASH) is the most severe form of nonalcoholic fatty liver disease (NAFLD). In adult patients, liver transplantation (LT) is the treatment of choice for end-stage liver disease secondary to NASH. However, little information is available regarding outcomes of LT in pediatric patients with NASH. We describe here a pediatric patient with NASH associated with hypopituitarism who underwent living donor liver transplantation (LDLT). An 11-year-old boy was diagnosed with a pituitary tumor, which was removed by trans-interhemispheric approach following bifrontal craniotomy. Histopathological examination revealed a mature teratoma. Eighteen months later, magnetic resonance imaging showed recurrence of the pituitary tumor, which was found to be a germinoma. He underwent 3 months of chemoradiotherapy, with a complete response. He gradually became obese, with elevated transaminase levels. At age 15 years, he developed fatigue and dyspnea and was found to have liver cirrhosis secondary to NASH with severe hepatopulmonary syndrome. He underwent LDLT using a right liver graft from his mother. Twelve months later, abdominal computed tomography showed recurrence of NAFLD. Five years after the LDLT, transaminases were slightly elevated. Growth hormone replacement therapy was started, reducing transaminase levels to their normal ranges. Ten years after LDLT, fatty liver remains stable, although his body mass index has not been reduced. Growth hormone replacement therapy may be effective in graft maintenance. This is the first case report of a patient with maintained stable liver function 10 years after LDLT for pediatric NASH.

Dexmedetomidine Attenuates Bilirubin-Induced Lung Alveolar Epithelial Cell Death In Vitro and In Vivo

Objective:

To investigate bilirubin-induced lung alveolar epithelial cell injury together with the protection afforded by dexmedetomidine.

Design:

Prospective, randomized, controlled study.

Setting:

Research laboratory.

Subjects:

Sprague Dawley rats.

Interventions:

Alveolar epithelial A549 cell lines were cultured and received bilirubin (from 0 to 160 μM) to explore the protective pathway of dexmedetomidine on bilirubin-induced alveolar epithelial cell injury assessed by immunochemistry and flow cytometry. Sprague-Dawley rats were subjected to common bile duct ligation surgery to explore the protective effect of dexmedetomidine on hyperbilirubinemia-induced alveolar epithelial cell injury and respiratory failure in comparison with the Sham (subjected to the surgery procedure but without bile duct ligation) or dexmedetomidine control (only received intraperitoneal injection of dexmedetomidine).

Measurements and Main Results:

In vitro, dexmedetomidine reversed the collapse of mitochondrial membrane potential (Δψm), upregulation of cytochrome C, B cell leukemia 2 associated X protein, and cleaved-caspase 3 and 9 in A549 epithelial cells with bilirubin challenge. Furthermore, dexmedetomidine reversed the arrest of cell cycle and the downregulation of the transforming growth factorβ, phosphorylated mammalian target of rapamycin, and p42/44 mitogen-activated protein kinase induced by bilirubin. In vivo, pulmonary edema and inflammation were found after common bile duct ligation. Bilirubin and Paco₂ were significantly increased, and oxygen (Pao₂) was significantly decreased in the blood of common bile duct ligation rats from the postsurgery day 7 to day 21 when compared with those in the sham controls, respectively (p < 0.01). Daily intraperitoneal injection of dexmedetomidine significantly alleviated the lung edema and injury and prevented respiratory failure.

Conclusion:

Our data both in vitro and in vivo demonstrated that dexmedetomidine protected alveolar epithelial cell from bilirubin-induced injury. Dexmedetomidine may be a good choice of anesthetic/sedative for patients with chronic liver disease during the perioperative period.

Cardiovascular dysfunction in patients with liver cirrhosis

Hyperdynamic syndrome is a well-known clinical condition found in patients with cirrhosis and portal hypertension, characterized by increased heart rate and cardiac output, and reduced systemic vascular resistance and arterial blood pressure. The leading cause of hyperdynamic circulation in cirrhotic patients is peripheral and splanchnic vasodilatation, due to an increased production/activity of vasodilator factors and decreased vascular reactivity to vasoconstrictors. The term "cirrhotic cardiomyopathy" describes impaired contractile responsiveness to stress, diastolic dysfunction and electrophysiological abnormalities in patients with cirrhosis without known cardiac disease. Underlying circulatory and cardiac dysfunctions are the main determinant in the development of hepatorenal syndrome in advanced cirrhosis. Moreover, the clinical consequences of cirrhosis-related cardiovascular dysfunction are evident during and after liver transplantation, and after transjugular intrahepatic portosystemic shunt insertion. Cardiovascular complications following these procedures are common, with pulmonary edema being the most common complication. Other complications include overt heart failure, arrhythmia, pulmonary hypertension, pericardial effusion, and cardiac thrombus formation. This review discusses the circulatory and cardiovascular dysfunctions in cirrhosis, examining the pathophysiologic and clinical implications in light of the most recent published literature.