The hepatopulmonary syndrome: new name, old complexities

Bilateral Arteriovenous Shunting Through Pial and Perforating Vessels With Multiple Strokes in a Patient With Hepatopulmonary Syndrome

Hepatopulmonary syndrome (HPS) is a condition characterized by chronic liver disease, intrapulmonary arteriovenous shunting, and increased alveolar-arterial oxygen gradient. This case report presents a 54-year-old male patient with a history of stroke, liver cirrhosis, portal vein thrombosis, hypertension, diabetes, and bladder cancer, who presented with worsening headaches and confusion over the course of five years. Digital subtraction angiogram (DSA) revealed multiple bilateral arteriovenous shunts, suggesting a shunting mechanism similar to that observed in HPS. We propose that this unique case could provide valuable insights into the parallels between the pathophysiology of HPS and diffuse arteriovenous shunting in the brain and the increased risk of ischemic and hemorrhagic events in both cases. Further studies are needed to establish a clearer understanding of this relationship and its implications for patients with chronic liver disease.

Development of albumin monitoring system with hepatic hypoxia-on-a-chip

Hypoxia plays an essential role in the pathogenesis of various liver diseases, and albumin is one of the important biomarkers secreted by the liver. In this study, we developed an albumin monitoring system composed of hepatic hypoxia-on-a-chip and an albumin sensor to study liver function change due to hypoxia. In hepatic hypoxia-on-a-chip, we vertically stack an oxygen-scavenging channel on a liver on a chip with a thin gas-permeable membrane in the middle. This unique design of the hepatic hypoxia-on-a-chip can help to induce hypoxia quickly, attaining <5% within 10 min. An electrochemical albumin sensor was fabricated based on the covalent immobilization of antibodies on the Au electrode to monitor albumin secreting function on the hepatic hypoxia-on-a-chip. Standard albumin samples spiked in PBS, and culture media were measured by the electrochemical impedance spectroscopy using the fabricated immunosensor. The LOD was calculated to be 10 ag/mL in both cases. Using the electrochemical albumin sensor, we measured albumin secretion in normoxia and hypoxia in the chips. The albumin concentration decreased to 27% after 24 h in hypoxia compared to normoxia. This response was consistent with physiological studies. With technical refinements, the present albumin monitoring system can be a powerful tool in studying hepatic hypoxia with real-time liver function monitoring.

Hepatopulmonary syndrome: An update

Hepatopulmonary syndrome (HPS) is characterized by defects in oxygenation caused by intra-pulmonary vasodilation occurring because of chronic liver disease, portal hypertension, or congenital portosystemic shunts. Clinical implications of portal hypertension are very well-known, however, awareness of its effect on multiple organs such as the lungs are less known. The presence of HPS in chronic liver disease is associated with increased mortality. Medical therapies available for HPS have not been proven effective and definitive treatment for HPS is mainly liver transplantation (LT). LT improves mortality for patients with HPS drastically. This article provides a review on the definition, clinical presentation, diagnosis, and management of HPS.

Tea polyphenols and Levofloxacin alleviate the lung injury of hepatopulmonary syndrome in common bile duct ligation rats through Endotoxin -TNF signaling

BACKGROUND & AIMS

Hepatopulmonary syndrome (HPS) is characterized by pulmonary vasodilation and arterial blood oxygen desaturation in patients with chronic liver disease. Generally, common bile duct ligation (CBDL) rats are a suitable experimental model for studying hepatopulmonary syndrome. Our previous study demonstrated that endotoxin surges markedly, followed by bacterial translocation and the loss of liver immune function in all the stages of CBDL, thereby contributing to the pathogenesis of HPS. However, the mechanisms behind the increase of the endotoxin and how to alleviate it have not yet been elucidated. Pulmonary injury induced by increased bilirubin, endotoxin, and inflammatory mediators occurs in the early and later stages of CBDL. This study assessed the effects of Tea polyphenols (TP) and Levofloxacin on endotoxin reduction and suppression of lung injury in HPS rats in the long and short term, respectively.

METHODS

Morphological change of pulmonary injury, HPS relative index, endotoxin concentration, and the activation extent of Malondialdehyde (MDA) and Myeloperoxidase (MPO) were evaluated in CBDL rats with or without TP and Levofloxacin for three weeks or six weeks. The inflammation factors of serum, lung tissue, and BALF were then compared at the same condition for the two time periods. This was followed by adoption of the network pharmacology approach, which was mainly composed of active component gathering, target prediction, HPS gene collection, network analysis, and gene enrichment analysis. Finally, the mRNA and protein levels of the inflammatory factors were studied and relative signaling expression was assessed using RT-PCR and Western blot analysis.

RESULTS

The obtained results indicated that the pulmonary injury manifestation was perceived and endotoxin, MDA, and MPO activation were markedly increased in the early and later stages of CBDL. TP and Levofloxacin treatment alleviated endotoxin infection and inflammation factor expression three weeks and six weeks after CBDL. In addition, Levofloxacin displayed a short time anti-bacterial effect, while TP exerted a long period function. TP and Levofloxacin also reduced TNF-α, TGF-β, IL-1β, PDGF-BB, NO, ICAM-1, and ET-1 expression on the mRNA or protein expression. With regard to the pharmacological mechanism, the network analysis indicated that 12 targets might be the therapeutic targets of TP and Levofloxacin on HPS, namely ET-1, NOs3, VEGFa, CCl2, TNF, Ptgs2, Hmox1, Alb, Ace, Cav1, and Mmp9. The gene enrichment analysis implied that TP and Levofloxacin probably benefited patients with HPS by modulating pathways associated with the AGE-RAGE signaling pathway, the TNF signaling pathway, the HIF-1 signaling pathway, the VEGF signaling pathway, and the IL-17 signaling pathway, Rheumatoid arthritis, Fluid shear stress, and atherosclerosis. Finally, the TNF-α level was mainly diminished on the protein level following CBDL.

CONCLUSIONS

TP and Levofloxacin could alleviate pulmonary injury for short and long period, respectively, while at the same time preventing endotoxin and the development of HPS in CBDL rats. These effects are possibly associated with the regulation of the Endotoxin -TNF-α pathways.

Smoking and Liver Disease

Cigarette smoking is the leading cause of preventable disease and death in the United States, causing approximately 480,000 deaths per year, which is equivalent to 1 in 5 deaths being attributable to tobacco use. The adverse effects of cigarette smoking on the lungs and cardiovascular system are well described; however, the detrimental effects of smoking on the liver are not as well defined. Smoking affects the liver via 3 separate mechanisms: toxic (both direct and indirect), immunologic, and oncogenic. There is an emerging body of evidence of an association between cigarette smoking and progression of fibrosis in chronic liver diseases such as nonalcoholic fatty liver disease and primary biliary cholangitis. Smoking is associated with accelerated development of hepatocellular carcinoma in patients with chronic hepatitis B or C virus infection. Tobacco smoking adversely affects lung function, which increases physical limitations and may preclude liver transplantation. Following liver transplantation, smoking is associated with several adverse outcomes, including increased risk of de novo malignancy, vascular complications, and nongraft-associated mortality. The respiratory illness caused by the novel coronavirus disease 2019 serves as a good example of the complex interplay between the lungs and the liver. It is evident that cigarette smoking has important negative effects on a multitude of liver diseases and that patients' smoking cessation must be prioritized. The data are limited, and more research is needed to better understand how smoking affects the liver. This article summarizes what is known about the pathologic effects of cigarette smoking on common liver diseases.

Hepatopulmonary Syndrome and Portopulmonary Hypertension: Current Status and Implications for Liver Transplantation

PURPOSE OF REVIEW

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PoPH) are both pulmonary vascular complications of advanced liver disease; however, these syndromes have distinct pathophysiology, clinical implications, and management.

RECENT FINDINGS

While both conditions are associated with portal hypertension, HPS results from diffuse pulmonary capillary vasodilation and PoPH results from vasoconstriction and vascular remodeling of pulmonary arteries. In HPS, no medical therapies clearly improve outcomes; however, patients have excellent post-LT outcomes with near uniform reversal of hypoxemia. In PoPH, several medical therapies used in idiopathic pulmonary hypertension have been shown improve pulmonary hemodynamics, symptoms, and potentially LT outcomes; however, further study is needed to determine best treatment regimens, long-term outcomes on medical therapy, and role of LT.

SUMMARY

While HPS results in severe hypoxemia that is usually reversible by LT, PoPH patients develop progressive pulmonary hypertension that may improve with medical therapy.

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.

Hepatopulmonary Syndrome and Post-Liver Transplantation Complications: A Case-Control Study

BACKGROUND

Although liver transplantation (LT) improves survival in cirrhotic patients with hepatopulmonary syndrome (HPS), few data exist concerning post-operative complications in these patients.

OBJECTIVE

To compare complications after LT between patients with and without HPS.

METHODS

In a case-control study, we retrospectively analyzed all patients who underwent LT in our center from January 2010 to July 2016. We compared cases of identified HPS to controls matched for age, MELD score, comorbidities, red blood cells transfused, and highest dosage of norepinephrine perfused during transplantation.

RESULTS

Among 451 transplanted patients, we identified 71 patients with HPS who could be analyzed. We found a significantly (p<0.001) higher number of post-operative complications in patients with HPS (median 5 vs 3), with more occurrence of cardiac, infectious and surgical complications than in the controls: 39.4% vs 12.7% (p<0.001), 81.7% vs 49.3% (p<0.001), and 59.2% vs 40.1% (p<0.029), respectively. There were also more ICU readmissions at 1 month among HPS patients (10 vs 1, p=0.01). There was no significant difference concerning ventilation data, lengths of ICU or hospital stay (8.5 [range 3-232] and 32 [14-276] days, respectively on the whole cohort) and death in the ICU (4.2% on the whole cohort). The 1-year survival was higher in HPS patients (94.4% vs 81.1%, p=0.034); there was no difference in 5-year survival.

CONCLUSION

HPS patients seem to have a higher number of complications in the first month following LT.

Hepatopulmonary Disorders: Gas Exchange and Vascular Manifestations in Chronic Liver Disease

This review concentrates on the determinants of gas exchange abnormalities in liver-induced pulmonary vascular disorders, more specifically in the hepatopulmonary syndrome. Increased alveolar-arterial O₂ difference, with or without different levels of arterial hypoxemia, and reduced diffusing capacity represent the most characteristic gas exchange disturbances in the absence of cardiac and pulmonary comorbidities. Pulmonary gas exchange abnormalities in the hepatopulmonary syndrome are unique encompassing all three pulmonary factors determining arterial PO₂ , that is, ventilation-perfusion imbalance, increased intrapulmonary shunt and oxygen diffusion limitation that, combined, interplay with two relevant nonpulmonary determinants, that is, increased total ventilation and high cardiac output. Behind the complexity of this lung-liver association there is an abnormal pulmonary vascular tone that combines inhibition of hypoxic pulmonary vasoconstriction with a reduced (or blunted) hypoxic vascular response. The pathology and pathobiology include the presence of intrapulmonary vascular dilatations with or without pulmonary vascular remodeling, i.e. angiogenesis. Liver transplantation, the only effective therapeutic approach to successfully improve and resolve the vast majority of complications induced by the hepatopulmonary syndrome, along with a large list of frustrating pharmacologic interventions, are also reviewed. Another liver-induced pulmonary vascular disorder with less gas exchange involvement, such as portopulmonary hypertension, is also considered. © 2018 American Physiological Society. Compr Physiol 8:711-729, 2018.

Successful venoarterial extracorporeal membrane oxygenation for prolonged hepatopulmonary syndrome following pediatric liver transplantation: A case report and review of the literature

HPS is a major complicating feature of end-stage liver disease. Diagnosis is clinical, and LT is the only definitive treatment. While the general impression is that HPS improves quickly after transplantation, it may not always be the case. We describe the smallest reported child with HPS prior to LT and requiring prolonged venoarterial extracorporeal membrane oxygenation after LT; especially as it is a rare occurrence, physician managing such cases should be aware of the circumstances under which HPS may require specific treatment.

ALTERAÇÕES DO SISTEMA CARDIOPULMONAR DE PACIENTES CIRRÓTICOS

RESUMO Introdução: A cirrose gera alterações nas trocas gasosas e a desnutrição proteico-calórica em pacientes hepatopatas. Objetivo: Avaliar e comparar as variáveis cardiopulmonares, a força do aperto de mão (FAM) e a composição corporal entre pacientes cirróticos pelo vírus da hepatite C e indivíduos saudáveis, e correlacionar o consumo máximo de oxigênio (VO2MAX) com a FAM. Métodos: Esta pesquisa caracteriza-se como estudo de caso-controle composto por 36 participantes (18 pacientes cirróticos com HCV e 18 indivíduos hígidos) de ambos os sexos, maiores de 18 anos. A força de preensão palmar foi mensurada por dinamometria com dinamômetro mecânico de empunhadura com alça ajustável. As variáveis ventilatórias foram avaliadas por ergoespirometria com teste de carga progressiva em cicloergômetro. A composição corporal foi mensurada por um técnico em cineantropometria nível II. Foram utilizados os testes t independente e Mann-Whitney para comparação entre os grupos e a correlação de Spearman para associação entre as variáveis. Resultados: Foram encontradas diferenças no consumo máximo de oxigênio 16,20 (11,60-18,55), mediana e intervalo interquartil x 19,90 (16,27-26,85), ventilação 45,40 (36,45-54,20) x 63,40 (50,40-78,00), produção de dióxido de carbono 785,88 (655,81-963,14) x 988,04 (826,93-1546,21), frequência cardíaca máxima (127,66 ± 23,26 média e ± DP) x (146,29 ± 23,31), primeiro limiar ventilatório (10,700 ± 3,19) x (14,912 ± 4,45) e segundo limiar ventilatório (14,16 ± 4,48) x (18,25 ± 5,54) entre cirróticos e controles, respectivamente. Encontramos correlação positiva moderada entre o consumo máximo de oxigênio e a força do aperto de mão (r = 0,474, p = 0,047). Conclusão: Existem alterações nas variáveis cardiopulmonares e há associação entre o VO2MAX e a FAM em pacientes cirróticos pelo vírus da hepatite C.

CT Scan Does Not Differentiate Patients with Hepatopulmonary Syndrome from Other Patients with Liver Disease

Background

Hepatopulmonary syndrome (HPS) is defined by liver dysfunction, intrapulmonary vascular dilatations, and impaired oxygenation. The gold standard for detection of intrapulmonary vascular dilatations in HPS is contrast echocardiography. However, two small studies have suggested that patients with HPS have larger segmental pulmonary arterial diameters than both normal subjects and normoxemic subjects with cirrhosis, when measured by CT. We sought to compare CT imaging-based pulmonary vasodilatation in patients with HPS, patients with liver dysfunction without HPS, and matching controls on CT imaging.

Methods

We performed a retrospective cohort study at two quaternary care Canadian HPS centers. We analyzed CT thorax scans in 23 patients with HPS, 29 patients with liver dysfunction without HPS, and 52 gender- and age-matched controls. We measured the artery-bronchus ratios (ABRs) in upper and lower lung zones, calculated the “delta ABR” by subtracting the upper from the lower ABR, compared these measurements between groups, and correlated them with clinically relevant parameters (partial pressure of arterial oxygen, alveolar-arterial oxygen gradient, macroaggregated albumin shunt fraction, and diffusion capacity). We repeated measurements in patients with post-transplant CTs.

Results

Patients had significantly larger lower zone ABRs and delta ABRs than controls (1.20 +/- 0.19 versus 0.98 +/- 0.10, p<0.01; and 0.12 +/- 0.17 versus -0.06 +/- 0.10, p<0.01, respectively). However, there were no significant differences between liver disease patients with and without HPS, nor any significant correlations between CT measurements and clinically relevant parameters. There were no significant changes in ABRs after liver transplantation (14 patients).

Conclusions

Basilar segmental artery-bronchus ratios are larger in patients with liver disease than in normal controls, but this vasodilatation is no more severe in patients with HPS. CT does not distinguish patients with HPS from those with uncomplicated liver disease.

Left Ventricular Dilation and Pulmonary Vasodilatation after Surgical Shunt for Treatment of Pre-Sinusoidal Portal Hypertension

Objective

The aim of this study was to prospectively investigate the long-term cardiovascular and pulmonary hemodynamic effects of surgical shunt for treatment of portal hypertension (PH) due to Schistosomiasis mansoni.

Location

The University of São Paulo Medical School, Brazil; Public Practice.

Methods

Hemodynamic evaluation was performed with transesophageal Doppler and contrast-enhanced echocardiography (ECHO) on twenty-eight participants with schistosomal portal hypertension. Participants were divided into two groups according to the surgical procedure used to treat their schistosomal portal hypertension within the last two years: group 1—distal splenorenal shunt (DSRS, n = 13) and group 2—esophagogastric devascularization and splenectomy (EGDS, n = 15).

Results

The cardiac output (5.08 ± 0.91 L/min) and systolic volume (60.1 ± 5.6 ml) were increased (p = 0.001) in the DSRS group. DSRS participants had a significant increase (p < 0.0001) in their left ventricular end-systolic and end-diastolic diameters as well as in their left ventricular end-diastolic and end-systolic volumes (p < 0.001) compared with the preoperative period. No statistically significant difference was found in the patients who underwent EGDS. ECHO revealed intrapulmonary vasodilatation (IPV) in 18 participants (64%), 9 DSRS and 9 EGDS (p > 0.05).

Conclusions

The late increase in the cardiac output, stroke volume and left ventricular diameters demonstrated left ventricular dilatation after a distal splenorenal shunt. ECHO revealed a greater prevalence for IPV in patients with schistosomiasis than has previously been described in patients with PH from liver cirrhosis.

Hepatopulmonary Syndrome and Liver Transplantation: A Recent Review of the Literature

A severe and common pulmonary vascular complication of liver disease is hepatopulmonary syndrome (HPS). It is a triad of liver dysfunction and/or portal hypertension, intrapulmonary vascular dilatations, and increased alveolar-arterial oxygen gradient. Prevalence varies according to various study groups from 4%-47%. While the most common presenting symptom of HPS is dyspnea, it is usually asymptomatic, and thus all liver transplant candidates should be screened for its presence. Pulse oximetry is a useful screening method, but arterial blood gas examination is the gold standard. If there is an abnormal P (A-a)O2 gradient, microbubble transthoracic echocardiography should be done for diagnosis. Outcome is unpredictable, and there is currently no effective medical therapy. The only effective therapy is considered to be liver transplantation. Complete resolution of HPS after liver transplantation is seen within a year in most HPS patients.

Inflammatory bowel diseases, chronic liver diseases and the lung

This review is devoted to the distinct associations of inflammatory bowel diseases (IBD) and chronic liver disorders with chronic airway diseases, namely chronic obstructive pulmonary disease and bronchial asthma, and other chronic respiratory disorders in the adult population. While there is strong evidence for the association of chronic airway diseases with IBD, the data are much weaker for the interplay between lung and liver multimorbidities. The association of IBD, encompassing Crohn's disease and ulcerative colitis, with pulmonary disorders is underlined by their heterogeneous respiratory manifestations and impact on chronic airway diseases. The potential relationship between the two most prevalent liver-induced pulmonary vascular entities, i.e. portopulmonary hypertension and hepatopulmonary syndrome, and also between liver disease and other chronic respiratory diseases is also approached. Abnormal lung function tests in liver diseases are described and the role of increased serum bilirubin levels on chronic respiratory problems are considered.

Hepatopulmonary Syndrome

Hepatopulmonary syndrome (HPS) is a pulmonary complication observed in patients with chronic liver disease and/or portal hypertension, attributable to an intrapulmonary vascular dilatation that may induce severe hypoxemia. Microvascular dilation and angiogenesis in the lung have been identified as pathologic features that drive gas exchange abnormalities in experimental HPS. Pulse oximetry is a useful screening test for HPS, which can guide subsequent use of arterial blood gases. Contrast-enhanced echocardiography, perfusion lung scanning, and pulmonary arteriography are three currently used diagnostic imaging modalities that identify the presence of intrapulmonary vascular abnormalities. The presence of HPS increases mortality and impairs quality of life, but is reversible with liver transplantation. No medical therapy is established as effective for HPS. At the present time, liver transplantation is the only available treatment for HPS.

Cirrhotic cardiomyopathy: pathogenesis and clinical relevance

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

Hepatopulmonary syndrome and portopulmonary hypertension

Hepatopulmonary syndrome and portopulmonary hypertension are 2 of many diseases that affect the lungs in patients with liver disease. The 2 vascular conditions are often confused. We review both hepatopulmonary syndrome and portopulmonary hypertension to better understand their pathophysiologies, clinical presentations, tools to aid in differentiating and diagnosing the disease states, treatment options, and influences on patient prognosis. We also consider patient viability for liver transplantation.

Parenchymal alterations in cirrhotic livers in patients with hepatopulmonary syndrome or portopulmonary hypertension

Hepatopulmonary syndrome (HPS) and portopulmonary hypertension (PPH) are distinct pulmonary vascular complications of cirrhosis. Little is known about possible associated hepatic histopathological features. Explanted livers from patients clinically diagnosed with HPS (n = 8) or PPH (n = 7) and cirrhotic explants from controls (n = 30) without HPS or PPH were evaluated with trichrome histochemistry, anti-glutamine synthetase (anti-GS), and anti-CD34 immunohistochemistry (IHC). Trichrome stains were characterized by cirrhotic nodules (CNs) of various sizes, including incomplete septal cirrhosis (ISC). ISC was overrepresented in the HPS (4/8 or 50%) and PPH livers (3/7 or 43%); in addition, neither group had micronodular cirrhosis. The control explants showed the entire spectrum of nodules: micronodular, macronodular, mixed CNs, and ISC (P = 0.04). The variability of cirrhosis severity was shown with the Laennec grading system (0-6). The cirrhosis of the majority of the HPS (6/8) and PPH livers (6/7) was scored as mild, whereas the control explants were more evenly distributed across the mild (14/30) and moderate/severe grades (16/30). GS positivity was retained in a perivenular location as the dominant pattern in each explant group. CD34 staining detected capillarized sinusoids of CNs as well as vascular channels within septa, but no significant differences were found between the groups. None of the observed light microscopy or histochemistry and IHC patterns showed a correlation with the underlying liver disease. Although our results demonstrate variable architectural and vascular remodeling within and between explant livers regardless of the presence or types of pulmonary complications, there were differences in explants with HPS or PPH versus controls that correlated with less severe cirrhosis.

Cirrhotic cardiomyopathy and hepatopulmonary syndrome: prevalence and prognosis in a series of patients

Hepatopulmonary syndrome (HPS) is of prognostic value in patients awaiting for orthotopic liver transplantation (OLT), but little is known about the effect of cirrhotic cardiomyopathy (CCM). The aim of the present study was to estimate the prevalence and possible relation between respiratory and cardiac abnormalities in a same series of patients awaiting OLT. Special attention was paid to the prognostic value of CCM in comparison to HPS. Eighty-three patients were included (19 females, 64 males; 52.1 ± 10.0 yrs). All had lung function testing with arterial blood gases and echocardiographic evaluation at rest with a contrast echocardiography in case of arterial oxygenation defect. To estimate the presence of CCM, patients underwent a complete left and right echocardiography and Doppler examination. Complete echocardiographic assessment could be obtained in 64 of the 83 patients of the study. HPS was observed in 16.9% (14/83) and CCM in 23.4% (15/64) of patients. There was a tendency of more serious adverse events before and after OLT in patients with HPS in comparison to others but CCM was not of prognostic value. HPS and CCM were frequent in these patients awaiting OLT but both abnormalities were not found in the same patients. CCM was neither related to death before OLT nor to death or serious adverse events after OLT.

Pulmonary vascular complications of liver disease

Hepatopulmonary syndrome and portopulmonary hypertension are two pulmonary vascular complications of liver disease. The pathophysiology underlying each disorder is distinct, but patients with either condition may be limited by dyspnea. A careful evaluation of concomitant symptoms, the physical examination, pulmonary function testing and arterial blood gas analysis, and echocardiographic, imaging, and hemodynamic studies is crucial to establishing (and distinguishing) these diagnoses. Our understanding of the pathobiology, natural history, and treatment of these disorders has advanced considerably over the past decade; however, the presence of either still increases the risk of morbidity and mortality in patients with underlying liver disease. There is no effective medical treatment for hepatopulmonary syndrome. Although liver transplantation can resolve hepatopulmonary syndrome, there appears to be worse survival even with transplantation. Liver transplantation poses a very high risk of death in those with significant portopulmonary hypertension, where targeted medical therapies may improve functional status and allow successful transplantation in a small number of select patients.

Pentoxifylline in hepatopulmonary syndrome

AIM: To determine the effects of pentoxifylline (PTX) on clinical manifestations and evaluate arterial blood gas data in hepatopulmonary syndrome (HPS) in children.

METHODS: In a pilot study of 10 children with chronic liver disease, who had HPS, 20 mg/kg/d PTX was administered for 3 mo. Clinical data and arterial blood gas parameters were evaluated at baseline, the end of the treatment period, and 3 mo after drug discontinuation.

RESULTS: Six patients could tolerate PTX, while four patients experienced complications. Among patients who could tolerate PTX, there was a significant increase in arterial oxygen pressure (PaO₂) (P = 0.02) and oxygen saturation (SaO₂) (P = 0.04) and alveolar-arterial oxygen gradient (P = 0.02) after 3 mo of treatment. Significant decreases in PaO₂ (P = 0.02) and alveolar-arterial oxygen gradient (P = 0.02) were also seen after drug discontinuation.

CONCLUSION: PTX may improve PaO₂, SaO₂ and alveolar-arterial oxygen gradient in the early stage of HPS.

Hepatopulmonary syndrome: update on pathogenesis and clinical features

Hepatopulmonary syndrome (HPS) is a serious vascular complication of liver disease that occurs in 5-32% of patients with cirrhosis. The presence of HPS markedly increases mortality. No effective medical therapies are currently available and liver transplantation is the only established treatment option for HPS. The definition and diagnosis of HPS are established by the presence of a triad of liver disease with intrapulmonary vascular dilation that causes abnormal arterial gas exchange. Experimental biliary cirrhosis induced by common bile duct ligation in the rat reproduces the pulmonary vascular and gas exchange abnormalities of human HPS and serves as a pertinent animal model. Pulmonary microvascular dilation and angiogenesis are two central pathogenic features that drive abnormal pulmonary gas exchange in experimental HPS, and thus might underlie HPS in humans. Defining the mechanisms involved in the microvascular alterations of HPS has the potential to lead to effective medical therapies. This Review focuses on the current understanding of the pathogenesis, clinical features and management of HPS.

Hepatopulmonary syndrome in children with cirrhotic and non-cirrhotic portal hypertension: a single-center experience

BACKGROUND

Hepatopulmonary syndrome (HPS) is defined as an arterial oxygenation defect induced by intrapulmonary vascular dilatation (IPVD) associated with hepatic disease. The prevalence and clinical characteristics of HPS in portal hypertensive children is not well characterized.

AIMS

The aim of this study was to investigate the prevalence and clinical characteristics of HPS in 40 portal hypertensive children.

METHODS

We studied 40 children (11 girls and 29 boys; mean age, 111 months ± 52 months; range, 24-216 months) with portal hypertension (24 cirrhotic, 16 non-cirrhotic) for the presence of HPS using blood gas analysis, contrast-enhanced echocardiography (CEE), and Tc99m-macroaggregated albumin scintigraphy. Clinical and laboratory characteristics of patients were recorded. HPS was considered to be present in a patient with hypoxemia and/or an elevated alveolar-arterial oxygen gradient (PAaO(2)) ≥ 15 mmHg) and positive CEE and/or scintigraphy.

RESULTS

Elevated PAaO(2) was detected in 7 of 24 patients with cirrhosis. Four of them also had IPVD with CEE. An intrapulmonary shunt in Tc99m-MAA with CEE was shown in one patient. A diagnosis of HPS was made in 16.7% of the patients with cirrhosis. Cirrhotic patients without IPVD had significantly better hepatic function and lower pediatric end-stage liver disease scores. Although, 2 of the 16 patients with non-cirrhotic portal hypertension had elevated PAaO(2,) none of them showed IPVD. One normoxemic patient in the non-cirrhotic portal hypertension group showed IPVD with CEE. None of the non-cirrhotic patients fulfilled the diagnostic criteria of HPS.

CONCLUSION

Hepatopulmonary syndrome particularly occurs in cirrhotic portal hypertensive patients with severe hepatic dysfunction.

Hemodynamic alterations in cirrhosis and portal hypertension

Portal hypertension (PHT) is associated with hemodynamic changes in intrahepatic, systemic, and portosystemic collateral circulation. Increased intrahepatic resistance and hyperdynamic circulatory alterations with expansion of collateral circulation play a central role in the pathogenesis of PHT. PHT is also characterized by changes in vascular structure, termed vascular remodeling, which is an adaptive response of the vessel wall that occurs in response to chronic changes in the environment such as shear stress. Angiogenesis, the formation of new blood vessels, also occurs with PHT related in particular to the expansion of portosystemic collateral circulation. The complementary processes of vasoreactivity, vascular remodeling, and angiogenesis represent important targets for the treatment of portal hypertension. Systemic and splanchnic vasodilatation can induce hyperdynamic circulation which is related with multi-organ failure such as hepatorenal syndrome and cirrhotic cadiomyopathy.

The role of garlic in hepatopulmonary syndrome: a randomized controlled trial

BACKGROUND

Increased nitric oxide production in cirrhosis has been commonly implicated in the genesis of hepatopulmonary syndrome (HPS). Initial studies suggested that garlic, a constituent of the daily diet, may have a role in the treatment of HPS by altering nitric oxide production.

OBJECTIVE

To evaluate the effects of oral garlic supplementation on arterial blood gas parameters, and overall morbidity and mortality in patients with HPS.

METHODS

Twenty-one and 20 HPS patients were randomly assigned to receive either oral garlic supplementation or placebo, respectively, and were evaluated monthly over a period of nine to 18 months.

RESULTS

After nine months, garlic supplementation was associated with a 24.66% increase in baseline arterial oxygen levels (83.05 mmHg versus 66.62 mmHg; P<0.001), compared with only a 7.37% increase (68.75 mmHg versus 64.05 mmHg; P=0.02) among subjects in the placebo group. There was also a 28.35% decrease in alveolar-arterial oxygen gradient (21.35 mmHg versus 29.77 mmHg; P<0.001) among patients with HPS who received garlic, in contrast with only a 10.73% decrease (29.11 mmHg versus 32.61 mmHg; P=0.12) among those in the placebo group. After nine months, the arterial oxygen level was significantly higher (83.05 mmHg versus 68.75 mmHg; P<0.001) and the alveolar-arterial oxygen gradient was significantly lower (21.35 mmHg versus 29.11 mmHg; P<0.001) among patients receiving garlic compared with those receiving placebo. Reversal of HPS was observed in 14 of 21 patients (66.67%) on garlic supplementation (intent-to-treat analysis) and in one of 20 patients (5%) on placebo. Two of 21 patients undergoing garlic supplementation died during follow-up in contrast to seven of 20 patients who were on placebo.

CONCLUSIONS

Garlic supplementation may be beneficial in patients with HPS for the reversal of intrapulmonary shunts as well as reducing hypoxemia and mortality.

Viral cirrhosis: an overview of haemostatic alterations and clinical consequences

Viral hepatitis is a major health problem worldwide, the principal cause of cirrhosis and hepatocarcinoma. Once cirrhosis occurs, the consequences of liver dysfunction and portal hypertension become evident and, sometimes, life threatening for patients. Among the various complications of liver cirrhosis, the alteration of haemostatic balance is often a hard challenge for the clinician, since it is capable to predispose both to bleeding or thrombosis. In this review, we analyze the principal aspects of procoagulant, anticoagulant and fibrinolytic capacity of cirrhotic patients, which appears to be variably altered in all these aspects, not only in the direction of a tendency to bleeding. Laboratory investigations, at present, may provide only a partial representation of this condition, because of the impossibility to obtain a test capable to furnish a global overview of the haemostatic system and to reproduce in vivo conditions. Furthermore, we describe the pathophysiological mechanisms underlying bleeding manifestations and thrombosis development in cirrhotic patients, which should be considered not only as obvious consequences of the advanced liver disease but, rather, as the result of a complex interaction between inherited and acquired factors.

Pulmonary manifestations of liver diseases

Respiratory problems are common in patients with chronic liver diseases. The most common causes are disorders that are not related to liver diseases such as asthma and COPD. In addition certain liver diseases that are associated with specific pulmonary abnormalities, and conditions associated with end stage liver disease like tense ascites and intercostal muscular wasting are considered. Finally two unique disorders characterizing by vascular abnormalities independent of cardiorespiratory disorder-the hepatopulmonary syndrome (HPS) and portopulmonary hypertension (POPH) are observed. These disorders have different pathogenesis, different clinical pictures, treatment and prognosis. This article reviews the epidemiology, pathophysiology, clinical features, evaluation and current therapy of these two disorders.

Hepatopulmonary syndrome: morbidity and survival after liver transplantation

Hepatopulmonary Syndrome (HPS) is a triad of liver disease, intrapulmonary vascular dilatation (IPVD), and arterial deoxygenation. Orthotopic liver transplantation (OLT) constitutes the only effective treatment; however, adverse outcomes have been reported. The aim of this study was to evaluate the early morbidity and short- and long-term survival after OLT for patients with and without HPS. We studied 59 transplant recipients divided into 2 groups: with HPS (HPS group n = 25) and without HPS (control group, n = 34) before the OLT. IPVD was diagnosed using transthoracic contrast-enhanced echocardiography. Arterial deoxygenation was defined as PA-a,O(2) >or= 15 mm Hg. The HPS and control groups were homogeneous regarding age (P = .36; 43.8 +/- 12.2 vs 46.9 +/- 13.5), gender (P = .47), male/female ratio (68%:32% and 78%:22%, respectively), and severity of liver disease. The PaO(2) was significantly lower (74.9 +/- 12.1 vs 93 +/- 6.4 mm Hg; P < .001) and the PA-a,O(2) was significantly higher in the HPS group (30.3 +/- 10.6 vs 11.0 +/- 7.0; P < .001). The percentage of severe (n = 3) and very severe (n = 1) hypoxemia was 16%. There were no significant differences between HPS and control groups regarding short- (68% vs 77%; P = .27) and long-term survival (60% vs 64%; P = .67) as well as among patients with mild, moderate, severe, or very severe HPS and the control group (P = .53). Also, intensive care unit (ICU) stay (7.0 vs 5.5; P = .41), duration of mechanical ventilation (38.0 vs 27.5; P = .43), reintubation rate (32.0% vs 23.5%; P = .45), and early postoperative complications (P = .72) were not different. In conclusion, there were no significant differences regarding the outcomes of OLT for patients with versus without HPS related to early morbidity or short- and long-term survival.

[Experimental models for assessment of pulmonary alterations in hepatopulmonary syndrome]

OBJECTIVE

The aim of this study was to identify the best experimental model in which to observe the pulmonary alterations characterizing hepatopulmonary syndrome (HPS).

METHODS

Male Wistar rats, with mean weight of 250 g, were used in four experimental models: inhaled carbon tetrachloride; intraperitoneal carbon tetrachloride; partial portal vein ligation; and bile duct ligation (BDL). The animals in all groups were divided into control and experimental subgroups. The following variables were measured: transaminase levels; blood gases; lipoperoxidation, using thiobarbituric acid reactive substances (TBARS) and chemiluminescence; and levels of superoxide dismutase (SOD) anti-oxidant activity. Anatomopathological examination of the lung was also performed.

RESULTS

There were statistically significant differences between the BDL control and BDL experimental groups: aspartate aminotransferase (105.3 +/- 43 vs. 500.5 +/- 90.3 IU/L); alanine aminotransferase (78.75 +/- 37.7 vs. 162.75 +/- 35.4 IU/L); alkaline phosphatase (160 +/- 20.45 vs. 373.25 +/- 45.44 IU/L); arterial oxygen tension (85.25 +/- 8.1 vs. 49.9 +/- 22.5 mmHg); and oxygen saturation (95 +/- 0.7 vs. 73.3 +/- 12.07%). Lipoperoxidation and antioxidant activity also differed significantly between the two BDL groups (control vs. experimental): TBARS (0.87 +/- 0.3 vs. 2.01 +/- 0.9 nmol/mg protein); chemiluminescence (16008.41 +/- 1171.45 vs. 20250.36 +/- 827.82 cps/mg protein); and SOD (6.66 +/- 1.34 vs. 16.06 +/- 2.67 IU/mg protein). The anatomopathological examination confirmed pulmonary vasodilatation in the BDL model. In the other models, there were no alterations that were characteristic of HPS.

CONCLUSIONS

The data obtained suggest that the BDL model can be used in future studies involving hepatic alterations related to oxidative stress and HPS.

Liver protection in the perioperative setting

With recent advances in surgical and anaesthetic management, clinical medicine has responded to societal expectations and the number of operations in patients with a high-risk of perioperative liver failure has increased over the last decades. This review will outline important pathophysiological alterations common in patients with pre-existing liver impairment and thus highlight the anaesthetic challenge to minimise perioperative liver insults. It will focus on the intraoperative balancing act to reduce blood loss while maintaining adequate liver perfusion, the various anaesthetic agents used and their specific effects on hepatic function, perfusion and toxicity. Furthermore, it will discuss advances in pharmacological and ischaemic preconditioning and summarise the results of recent clinical trials.

Hyperoxia prevents exercise-induced intrapulmonary arteriovenous shunt in healthy humans

The 100% oxygen (O(2)) technique has been used to detect and quantify right-to-left shunt for more than 50 years. The goal of this study was to determine if breathing 100% O(2) affected intrapulmonary arteriovenous pathways during exercise. Seven healthy subjects (3 females) performed two exercise protocols. In Protocol I subjects performed an incremental cycle ergometer test (60 W + 30 W/2 min; breathing room air, FIO2 = 0.209) and arteriovenous shunting was evaluated using saline contrast echocardiography at each stage. Once significant arteriovenous shunting was documented (bubble score = 2), workload was held constant for the remainder of the protocol and FIO2 was alternated between 1.0 (hyperoxia) and 0.209 (normoxia) as follows: hyperoxia for 180 s, normoxia for 120 s, hyperoxia for 120 s, normoxia for 120 s, hyperoxia for 60 s and normoxia for 120 s. For Protocol II, subjects performed an incremental cycle ergometer test until volitional exhaustion while continuously breathing 100% O(2). In Protocol I, shunting was seen in all subjects at 120-300 W. Breathing oxygen for 1 min reduced shunting, and breathing oxygen for 2 min eliminated shunting in all subjects. Shunting promptly resumed upon breathing room air. Similarly, in Protocol II, breathing 100% O(2) substantially decreased or eliminated exercise-induced arteriovenous shunting in all subjects at submaximal and in 4/7 subjects at maximal exercise intensities. Our results suggest that alveolar hyperoxia prevents or reduces blood flow through arteriovenous shunt pathways.

Pilot study of pentoxifylline in hepatopulmonary syndrome

Hepatopulmonary syndrome (HPS) results when chronic liver disease or portal hypertension causes intrapulmonary microvascular dilatation with hypoxemia. In experimental HPS, tumor necrosis factor alpha (TNF-alpha) overproduction contributes to vasodilatation, which is improved by pentoxifylline, a TNF-alpha inhibitor. The effectiveness of pentoxifylline in humans is unknown. The aim of this open-label, single-arm clinical trial was to assess the efficacy and tolerability of pentoxifylline in patients with cirrhosis and advanced HPS undergoing liver transplantation evaluation. Nine adults with cirrhosis and moderate to severe HPS were enrolled. All patients had an initial 2-week titration to a target dose of pentoxifylline of 400 mg by mouth every 8 hours, which was continued for 6 weeks. Baseline and follow-up arterial blood gases and TNF-alpha levels were evaluated. Adverse effects and tolerability were assessed. The 9 patients had a mean age of 55 +/- 10 years, and 67% were female. The most common causes of cirrhosis were hepatitis C virus and alcohol (55%). The mean Model for End-Stage Liver Disease score was 11 (range, 6-19), and patients had advanced hypoxemia [mean partial pressure of arterial oxygen (PaO(2)) = 54 +/- 12 mm Hg, mean alveolar-arterial oxygen gradient (A-a PaO(2)) = 57 +/- 15 mm Hg]. Of the 9 patients enrolled, follow-up blood gases were done in 7. There was no significant change in PaO(2) (P = 0.3) or A-a PaO(2) (P = 0.3) with treatment. Pentoxifylline was poorly tolerated. Nausea (100%) and vomiting (56%) were the predominant side effects, and only a single patient was able to complete full-dose therapy. Treatment with pentoxifylline did not improve arterial oxygenation in advanced HPS, and tolerance was limited by gastrointestinal toxicity.

Preoperative pulmonary assessment of children for liver transplantation

Pulmonary assessment should be part of the preoperative investigation of pediatric patients with chronic liver disease undergoing liver transplantation, as it allows the identification of pulmonary alterations that influence candidacy for transplantation and survival. To describe pulmonary changes found in pediatric patients who were candidates for liver transplantation. Retrospective study of 17 pediatric liver transplant candidates undergoing preoperative pulmonary evaluation assessing pulmonary clinical data, arterial blood gas analysis, CXR, respiratory function test by spirometry, pulmonary scintigraphy, and CEE. Ten patients presented normal chest roentgenograms. The most common radiographic change was interstitial infiltrate in the lung bases. Of the five patients with PaO(2) <70 mmHg, four had cyanosis and dyspnea and two were diagnosed with HPS with intrapulmonary shunt evidenced by contrast echocardiogram. Two patients presented with intrapulmonary shunt but without hypoxemia. Spirometry was normal in six patients, restrictive disturbance was evidenced in one patient, obstructive in three, and combined in two. The most common scintigraphic change was heterogeneous pulmonary perfusion. Pulmonary assessment should be performed routinely in pediatric patients prior to liver transplantation, even in asymptomatic patients. Pulmonary assessment may indicate changes such as HPS that can increase postoperative morbidity/mortality.

The management of portal hypertension: rational basis, available treatments and future options

Variceal bleeding is the last step in a chain of events initiated by an increase in portal pressure, followed by the development and progressive dilation of varices until these finally rupture and bleed. This sequence of events might be prevented - and reversed - by achieving a sufficient decrease in portal pressure. A different approach is the use of local endoscopic treatments at the varices. This article reviews the rationale for the management of patients with cirrhosis and portal hypertension, the current recommendations for the prevention and treatment of variceal bleeding, and outlines the unsolved issues and the perspectives for the future opened by new research developments.

[Hepatopulmonary syndrome in patients with advanced hepatic disease: study of a series of 24 cases]

BACKGROUND AND OBJECTIVE

To describe the characteristics observed in patients diagnosed of hepatopulmonary syndrome (HPS) waiting for orthotopic liver transplantation and those who underwent liver trasplantation.

PATIENTS AND METHOD

An observational prospective descriptive study was carried out of patients waiting for liver transplantation in whom data of liver illness and lung function tests were analyzed.

RESULTS

107 patients of 53.69 years average age were studied (7.7 standard deviation). 24 of them (22.4%) had criteria of HPS. Ortodeoxia was present in the 34% of cases. The lung function tests were normal. In the comparative study between patients with HPS and no HPS, differences in diffusion were found (7.1 vs. 8.6 mmol/min/kPa; p = 0.04), as well as in the shunt (8% vs. 5.3%; p = 0.05) and the forced expiratory volume in one second (2,390 vs. 2,743 ml; p = 0.03). Seven patients were transplanted with correction of oxygenation and vascular dilatations in all of them.

CONCLUSIONS

HPS is a frequent illness in patients waiting for orthotopic liver transplantation. The main alteration in the blood oxygenation seems owe to shunt, and the diffusion tests is the analysis that could best differentiate patients with HPS. Orthotopic liver transplantation corrects the syndrome in all cases.

Intrapulmonary shunting and pulmonary gas exchange during normoxic and hypoxic exercise in healthy humans

Exercise-induced intrapulmonary arteriovenous shunting, as detected by saline contrast echocardiography, has been demonstrated in healthy humans. We have previously suggested that increases in both pulmonary pressures and blood flow associated with exercise are responsible for opening these intrapulmonary arteriovenous pathways. In the present study, we hypothesized that, although cardiac output and pulmonary pressures would be higher in hypoxia, the potent pulmonary vasoconstrictor effect of hypoxia would actually attenuate exercise-induced intrapulmonary shunting. Using saline contrast echocardiography, we examined nine healthy men during incremental (65 W + 30 W/2 min) cycle exercise to exhaustion in normoxia and hypoxia (fraction of inspired O2 = 0.12). Contrast injections were made into a peripheral vein at rest and during exercise and recovery (3–5 min postexercise) with pulmonary gas exchange measured simultaneously. At rest, no subject demonstrated intrapulmonary shunting in normoxia [arterial Po2 (PaO2) = 98 ± 10 Torr], whereas in hypoxia (PaO2 = 47 ± 5 Torr), intrapulmonary shunting developed in 3/9 subjects. During exercise, ∼90% (8/9) of the subjects shunted during normoxia, whereas all subjects shunted during hypoxia. Four of the nine subjects shunted at a lower workload in hypoxia. Furthermore, all subjects continued to shunt at 3 min, and five subjects shunted at 5 min postexercise in hypoxia. Hypoxia has acute effects by inducing intrapulmonary arteriovenous shunt pathways at rest and during exercise and has long-term effects by maintaining patency of these vessels during recovery. Whether oxygen tension specifically regulates these novel pathways or opens them indirectly via effects on the conventional pulmonary vasculature remains unclear.

Intestinal endotoxemia plays a central role in development of hepatopulmonary syndrome in a cirrhotic rat model induced by multiple pathogenic factors

AIM: To characterize the correlation between severity of hepatopulmonary syndrome (HPS) and degree of hepatic dysfunction, and to explore how intestinal endotoxemia (IETM) affects the development of HPS in cirrhotic rats.

METHODS: Male Wister rats were fed with a diet containing maize flour, lard, cholesterol, and alcohol and injected subcutaneously with CCl₄ oil solution every two days for 8 wk to induce typical cirrhosis and development of HPS. The animals were also given a nitric oxide (NO) production inhibitor, N^ω-nitro-L-arginine methyl ester (L-NAME) intraperitoneally, and an iNOS inhibitor, aminoguanidine hydrochloride (AG) via gavage daily from the end of the 4th wk to the end of the 6th or 8th wk, or a HO-1 inhibitor, zinc protoporphyrin (ZnPP) intraperitoneally 12 h prior to killing. Blood, liver and lung tissues were sampled.

RESULTS: Histological deterioration of the lung paralleled to that of the liver in the cirrhotic rats. The number of pulmonary capillaries was progressively increased from 6.1 ± 1.1 (count/filed) at the 4th wk to 14.5 ± 2.4 (count/filed) at the 8th wk in the cirrhotic rats. Increased pulmonary capillaries were associated with increased blood levels of lipopolysaccharide (LPS) (0.31 ± 0.08 EU/mL vs control 0.09 ± 0.03 EU/mL), alanine transferase (ALT, 219.1 ± 17.4 U/L vs control 5.9 ± 2.2 U/L) and portal vein pressure. Compared with normal control animals, the number of total cells in bronchoalveolar lavage fluid (BALF) of the cirrhotic rats at the 8th wk was not changed, but the number of macrophages and the ratio of macrophages to total cells were increased by nearly 2-fold, protein expression of inducible nitric oxide synthase (iNOS) and endothelial nitric oxide synthase (eNOS) started to increase significantly at the 4th wk, and reached its peak at the 8th wk in the lung of cirrhotic rats. The increase of iNOS expression appeared to be quicker than that of eNOS. NO₂^-/NO₃^- was also increased, which was correlated to the increase of iNOS (r = 0.7699, P < 0.0001) and eNOS (r = 0.5829, P < 0.002). mRNA expression of eNOS and iNOS was highly consistent with their protein expression.

CONCLUSION: Progression and severity of HPS as indicated by both increased pulmonary capillaries and histological changes are closely associated with LPS levels and progression of hepatic dysfunction as indicated by increased levels of ALT and portal vein pressure. Intestinal endotoxemia plays a central role in the development of HPS in the cirrhotic rat model by inducing NO and/or CO.

Inhaled iloprost for hepatopulmonary syndrome: improvement of hypoxemia

Hepatopulmonary syndrome is characterized by advanced liver disease, hypoxemia, and intrapulmonary shunting. The only reported curative option is orthotopic liver transplantation. We describe here a beneficial effect of inhaled prostacyclin including a decrease in respiratory symptoms and improved oxygenation in this clinical situation, with no approved pharmacological long-term therapy. The prostanoid iloprost, approved for pulmonary and portopulmonary hypertension, caused an increase in oxygenation, relief of dyspnea, and increased exercise tolerance in a patient suffering from liver-cirrhosis-associated hepatopulmonary syndrome. After liver transplantation, restitution of hepatopulmonary syndrome did not occur immediately. Inhaling iloprost resulted in improved physical condition and better clinical rehabilitation potential until hypoxemia finally resolved 3 months after transplantation. Therefore, iloprost could improve quality of life in patients with hepatopulmonary syndrome waiting for liver transplantation and post surgery until the resolution of the hypoxemia.

Inflammation: a way to understanding the evolution of portal hypertension

BACKGROUND

Portal hypertension is a clinical syndrome that manifests as ascites, portosystemic encephalopathy and variceal hemorrhage, and these alterations often lead to death.

HYPOTHESIS

Splanchnic and/or systemic responses to portal hypertension could have pathophysiological mechanisms similar to those involved in the post-traumatic inflammatory response.The splanchnic and systemic impairments produced throughout the evolution of experimental prehepatic portal hypertension could be considered to have an inflammatory origin. In portal vein ligated rats, portal hypertensive enteropathy, hepatic steatosis and portal hypertensive encephalopathy show phenotypes during their development that can be considered inflammatory, such as: ischemia-reperfusion (vasodilatory response), infiltration by inflammatory cells (mast cells) and bacteria (intestinal translocation of endotoxins and bacteria) and lastly, angiogenesis. Similar inflammatory phenotypes, worsened by chronic liver disease (with anti-oxidant and anti-enzymatic ability reduction) characterize the evolution of portal hypertension and its complications (hepatorenal syndrome, ascites and esophageal variceal hemorrhage) in humans.

CONCLUSION

Low-grade inflammation, related to prehepatic portal hypertension, switches to high-grade inflammation with the development of severe and life-threatening complications when associated with chronic liver disease.