Combined exercise training improved exercise capacity and lung inflammation in rats with hepatopulmonary syndrome.

AIM: Physical exercise training attenuates pulmonary inflammation, but its effects on impaired respiratory function caused by hepatopulmonary syndrome (HPS) have not been evaluated. We determined if the combination of moderate intensity aerobic and resistance training during HPS development modifies exercise capacity, respiratory system mechanics, and lung inflammation responses. MAIN METHODS: Wistar rats were randomly divided into sham, HPS, and HPS + combined exercise training groups. Fifteen days after HPS induction, a moderate intensity aerobic plus resistance exercise training protocol was performed five times a week for 5 weeks on alternate days. Exercise capacity, respiratory system mechanics, lung inflammation, pulmonary morphology, and immunohistochemistry were evaluated. KEY FINDINGS: Overall, our findings indicated that combined exercise training efficiently increased the maximal running and resistance capacity of HPS animals. The training regimen reduced the expression of P2X7 in parenchymal leukocytes (P < 0.01), partially restored the expression of interleukin-10 in airway epithelium (P < 0.01), and increased the expression of TFPI in the airway epithelium (P < 0.01) as well as reduced its expression in parenchymal leukocytes (P < 0.01). However, exercise training did not attenuate HPS-induced respiratory mechanical derangements or lung tissue remodeling. SIGNIFICANCE: Combined exercise training can elicit adaptation with regard to both maximal running capacity and maximum strength and modify the expression of P2X7 and TFPI in parenchymal leukocytes and that of IL-10 in airway epithelium.

Non-invasive assessment of intrapulmonary shunt and ventilation to perfusion ratio in children with hepatopulmonary syndrome before and after liver transplantation.

OBJECTIVES: To use the oxyhaemoglobin dissociation curve (ODC) to non-invasively measure the ventilation perfusion ratio (VA/Q) and right-to-left intrapulmonary vascular shunt before and after liver transplantation (LT) in children with hepatopulmonary syndrome (HPS). To investigate whether the right-to-left shunt derived by ODC correlated with the shunt derived by technetium-99 labelled macroaggregated albumin lung perfusion scan (MAA). METHODS: A retrospective cohort study at King's College Hospital NHS Foundation Trust, London, UK was performed between 1998 and 2016. The VA/Q and right-to-left shunt were non-invasively measured pre and post LT. The pre-LT right-to-left intrapulmonary shunt was also measured by MAA. The non-invasively derived pre-LT shunt was correlated with the shunt derived by MAA. RESULTS: Fifteen children with HPS were studied with a median (IQR) age at LT of 8.8 (6.6-12.9) years. The median (IQR) pre-LT VA/Q [0.49 (0.42-0.65)] was lower compared to the post-LT VA/Q [0.61 (IQR 0.54-0.72), p = 0.012]. The median (IQR) pre-LT shunt was 19 (3-24) % which decreased to zero in all but one children post-LT, (p = 0.001). The MAA-derived shunt was significantly positively correlated with the ODC-derived shunt (r = 0.783, p = 0.001). The mean (SD) difference between shunt derived by ODC and shunt derived by MAA was 0.5 (7.2) %. CONCLUSIONS: Ventilation/perfusion impairment reverses but not completely resolves after liver transplantation in children with hepatopulmonary syndrome. The non-invasive method for estimating intrapulmonary shunting could be used as an alternative to the macroaggregated albumin scan in this population.

Impact of hypoxemia on pediatric liver transplantation for hepatopulmonary syndrome.

BACKGROUND: The treatment of choice for patients with cirrhosis and HPS is LT. The clinical manifestations associated with hypoxemia result in limitations and a poor health-related quality of life of affected patients. The present report aims to study the differences in outcomes between patients with PaO2  < 50 mm Hg and those with PaO2  ≥ 50 mm Hg. METHODS: This was a retrospective study of 21 patients under 18 years of age conducted from 2001 to 2018; the patients were divided into 2 groups: G1-PaO2  ≥ 50 mm Hg, 11 patients, and G2-PaO2  < 50 mm Hg, 10 patients. Demographic, clinical, laboratory, and perioperative data; outcome variables; and post-transplant survival were compared between the groups. RESULTS: In total, 2/11 (18.2%) patients in G1 and 8/10 (80%) patients in G2 required supplemental oxygen therapy at home (P = .005). Patients in G2 required prolonged MV (median 8.5 days in G2 vs 1 day in G1, P = .015) and prolonged ICU and hospital stays (P = .002 and P = .001, respectively). Oxygen weaning time was longer in G2 (median 127.5 days) than in G1 (median 3 days; P = .004). One (9.1%) patient in G1 and three (30%) patients in G2 died (P = .22). The survival at 90 months was 90.9% in G1 and 70% in G2 (P = .22). CONCLUSION: The survival between groups was similar. Patients with very severe HPS required a longer MV time, longer ICU and hospital stays, and a longer O2 weaning time than those with mild, moderate, or severe HPS.

Cardiovascular disorders in patients with congenital portosystemic shunts: 23 years of experience in a tertiary referral centre.

BACKGROUND: Congenital portosystemic shunts are rare vascular malformations that may have an impact on the heart-lung system. Associated congenital and/or acquired heart diseases are poorly reported. AIMS: To analyse cardiovascular disorders within a large congenital portosystemic shunt population, and develop a diagnostic strategy. METHODS: Among the 168 consecutive fetuses and children referred for congenital portosystemic shunt (1996-2019), patients presenting with at least one cardiovascular disorder, including congenital heart disease, heart failure, portopulmonary hypertension and/or hepatopulmonary syndrome, were reviewed retrospectively. Cardiovascular disorders were detected using echocardiography and one or more of the following: right-sided heart catheterization; contrast-enhanced transthoracic echocardiography; or lung perfusion radionuclide scan. RESULTS: Overall, 46/168 patients with a congenital portosystemic shunt (27.4%) had one or more clinically significant cardiovascular disorders. Congenital heart disease was present in 28 patients, including six with left heterotaxy. Heart failure was present in six fetuses and 21 neonates (eight without congenital heart disease, and 13 with congenital heart disease). In neonates without congenital heart disease, heart function recovered by the age of 3years. Portopulmonary hypertension was identified in 11 patients (mean age at diagnosis: 9years); it was fatal in one patient, and remained stable in five of six patients after congenital portosystemic shunt closure. In six patients, hepatopulmonary syndrome presented as hypoxia (mean age at diagnosis: 5.3years), which reversed after congenital portosystemic shunt closure. CONCLUSIONS: Evaluation and monitoring of the cardiopulmonary status of patients with a congenital portosystemic shunt is mandatory to detect and prevent cardiovascular complications. Furthermore, congenital portosystemic shunts must be sought in patients with unexplained cardiovascular disorders, especially when malformations are present.

Hepatopulmonary Syndrome in an Adolescent With Insidious Hypoxia and Small Intrahepatic Portal Venous Shunts: Posttransplant Benefit From Sildenafil.

We report a patient without known preexisting liver disease who presented with hepatopulmonary syndrome (HPS) due to aberrant intrahepatic portal venous development leading to portosystemic shunting. Liver transplantation resulted in resolution of portal hypertension and HPS and sildenafil was safely tolerated in the treatment of persistent fatigue and hypoxemia. Twelve months later, patient has normal allograft function and has returned to normal activity.

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.

Pulmonary Complications of Portal Hypertension.

The most common pulmonary complications of chronic liver disease are hepatic hydrothorax, hepatopulmonary syndrome, and portopulmonary hypertension. Hepatic hydrothorax is a transudative pleural effusion in a patient with cirrhosis and no evidence of underlying cardiopulmonary disease. Hepatic hydrothorax develops owing to the movement of ascitic fluid into the pleural space. Hepatopulmonary syndrome and portopulmonary hypertension are pathologically linked by the presence of portal hypertension; however, their pathophysiologic mechanisms are significantly different. Hepatopulmonary syndrome is characterized by low pulmonary vascular resistance secondary to intrapulmonary vascular dilatations and hypoxemia; portopulmonary hypertension features elevated pulmonary vascular resistance and constriction/obstruction within the pulmonary vasculature.

Outcomes of 50 Cases of Pediatric Liver Transplantation for Intrapulmonary Shunt While Considering the Deteriorated Prognosis of Severe Intrapulmonary Shunt Patients.

BACKGROUND: Intrapulmonary shunt (IPS) is recognized in 10% of chronic liver disease patients. Liver transplantation (LT) is associated with a high risk of morbidity and mortality in patients with IPS. PATIENTS AND METHODS: Of 519 pediatric LT cases between November 2005 and October 2018, 50 patients with IPS were enrolled in this study. The patients were divided into 3 groups, according to the shunt ratio, calculated by scintigraphy: mild (15%-20%, n = 26), moderate (20%-40%, n = 19), and severe (> 40%, n = 5). We compared the patients' characteristics before LT and the outcomes of LT between these groups. RESULTS: The major original disease resulting in LT in the mild and moderate groups was biliary atresia (73.1% and 52.6%, respectively), while that in the severe group was congenital portosystemic shunt (60%). The median ages at LT were 7.5, 6.1, and 8.3 years in the mild, moderate, and severe groups, respectively. All of the mild and moderate IPS patients lived; however, 3 patients with severe IPS (60.0%) died within 3 months. The shunt ratios of the mild and moderate IPS patients normalized within 2 years after LT, while the 2 surviving severe IPS patients showed a slight improvement. The autopsy findings of the lung in 1 deceased severe IPS patient showed medial hypertrophy and proliferation of intimal cells of the pulmonary arteries, suggesting a diagnosis of portopulmonary hypertension. CONCLUSIONS: LT can be safely performed for mild and moderate IPS patients; however, LT for severe IPS patients should be carefully indicated because concomitant portopulmonary hypertension may be masked by IPS.

Melatonin effects on pulmonary tissue in the experimental model of Hepatopulmonary Syndrome.

OBJECTIVE: To evaluate the pulmonary alterations of animals with Hepatopulmonary Syndrome (HPS) submitted to Biliary Duct Ligature (BDL), as well as the antioxidant effect of Melatonin (MEL). METHODS: Sixteen male Wistar rats, divided into four Sham groups: BDL group, Sham + MEL group and BDL + MEL. The pulmonary and hepatic histology, lipoperoxidation and antioxidant activity of lung tissue, alveolar-arterial O2 difference and lung / body weight ratio (%) were evaluated. RESULTS: When comparing the groups, could be observed an increase of vasodilation and pulmonary fibrosis in the BDL group and the reduction of this in relation to the BDL + MEL group. It was also observed significant changes in the activity of catalase, ApCO2, ApO2 in the LBD group when compared to the other groups. CONCLUSION: The use of MEL has been shown to be effective in reducing vasodilation, fibrosis levels and oxidative stress as well as gas exchange in an experimental HPS model.

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.

Roles of Endothelin B Receptors and Endothelial Nitric Oxide Synthase in the Regulation of Pulmonary Hemodynamic in Cirrhotic Rats.

INTRODUCTION: Hepatopulmonary syndrome and portopulmonary hypertension are common complications of liver disorders. This study aimed to determine roles of ET-B receptors and endothelial-derived NO synthase in the regulation of pulmonary hemodynamic in cirrhotic rats. METHODS: Male Sprague-Dawley rats were divided into the Sham and common bile duct ligation (CBDL) groups. After 28 days, animals were anesthetized, and the right ventricle, femoral artery, and vein cannulated. Then, intravenous injection of BQ-788 (a selective ET-B receptor antagonist) and L-NAME (eNOS inhibitor) were performed sequentially. RESULTS: After the first injection of BQ-788, the right ventricular systolic pressure (RVSP) and mean arterial systemic pressure increased only in the Sham group. L-NAME increased RVSP in the Sham and CBDL groups, whereas mean arterial systemic pressure elevated only in the Sham group significantly. Reinjection of BQ-788 increased RVSP in the Sham group, whereas it decreased RVSP in the CBDL group. Both plasma NO metabolites and lung endothelin-1 increased in the CBDL group. CONCLUSION: ET-B receptors on the endothelial cells play roles in the regulation of pulmonary and systemic vascular tone in normal condition through the NO-mediated pathway, whereas ET-B receptors on the smooth muscle cells have a role in the pulmonary vascular tone in liver cirrhosis.

Effect of Transjugular Intrahepatic Portosystemic Shunt Creation on Pulmonary Gas Exchange in Patients with Hepatopulmonary Syndrome: A Prospective Study.

PURPOSE: To evaluate effect of transjugular intrahepatic portosystemic shunt (TIPS) creation on pulmonary gas exchange in patients with hepatopulmonary syndrome (HPS). MATERIALS AND METHODS: All patients with cirrhosis or Budd-Chiari syndrome undergoing elective TIPS creation at a single institution between June 2014 and June 2015 were eligible for inclusion. Twenty-three patients with HPS (age 55.0 y ± 14.4; 11 men; Model for End-Stage Liver Disease score 10.2 ± 2.7) who achieved technical success were included in the analysis. Diagnosis of HPS was established by contrast-enhanced echocardiography demonstrating intrapulmonary vascular dilatation and arterial blood gas analysis demonstrating arterial oxygenation defects. RESULTS: Mean portosystemic gradient was reduced from 21.7 mm Hg ± 8.3 before TIPS creation to 10.8 mm Hg ± 5.1 after TIPS creation. Among the 5 (21.7%) patients who experienced dyspnea, 4 (80.0%) reported improvement after TIPS creation. This improvement was not maintained at 3 months after TIPS creation in 2 (50.0%) patients. Compared with before TIPS creation, mean change in alveolar-arterial oxygen gradient for patients with HPS was statistically significant at 1 month (-9.2 mm Hg ± 8.0; P < .001) after TIPS creation, but not at 2-3 days (-0.9 mm Hg ± 10.5; P = .678) or 3 months (-3.4 mm Hg ± 11.8; P = .179) after TIPS creation. CONCLUSIONS: TIPS creation can transiently improve pulmonary gas exchange in patients with HPS.

Evidence for an Association Between Intrahepatic Vascular Changes and the Development of Hepatopulmonary Syndrome.

BACKGROUND: Hepatopulmonary syndrome (HPS) is characterized by an arterial oxygenation defect, defined by an increased alveolar-arterial oxygen gradient, induced by pulmonary vascular dilatations in the context of liver disease. The pathogenesis of HPS is poorly understood. Morphologic changes associated with HPS are unknown. This study aimed at describing imaging and pathology changes associated with HPS. METHODS: We performed a case-control study in candidates for transplant with suspicion of cirrhosis. Each patient with HPS (Pao2 ≤ 70 mm Hg) was matched to three control subjects for age, cause, and liver disease severity. Pretransplant thoracic and abdominal imaging and explanted livers were reviewed. RESULTS: CT scans and Doppler ultrasounds from 21 patients with HPS were compared with those from 63 control subjects. HPS was associated with a two- to threefold higher prevalence of obstructed intrahepatic portal branches, of slowed or hepatofugal portal blood flow, and of large abdominal portosystemic shunts. Hepatic artery diameter was also larger in patients with HPS. Explanted livers from 19 patients with HPS were compared with those from 57 control subjects. HPS was associated with a fourfold higher prevalence of portal venule thrombosis and a ninefold higher prevalence of extensive vascular proliferation within fibrous septa. Obstruction of centrilobular venules, sinusoidal dilatation, and liver parenchymal extinction were also more common in patients with HPS. CONCLUSIONS: HPS is associated with intrahepatic vascular changes and with features suggesting severe portal hypertension. These results raise the hypothesis that intrahepatic vascular changes precipitate the development of HPS, opening new therapeutic perspectives for HPS.

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.

Melatonin effects on pulmonary tissue in the experimental model of Hepatopulmonary Syndrome / Efeitos da melatonina sobre o tecido pulmonar no modelo experimental de Síndrome Hepatopulmonar

ABSTRACT Objective: To evaluate the pulmonary alterations of animals with Hepatopulmonary Syndrome (HPS) submitted to Biliary Duct Ligature (BDL), as well as the antioxidant effect of Melatonin (MEL). Methods: Sixteen male Wistar rats, divided into four Sham groups: BDL group, Sham + MEL group and BDL + MEL. The pulmonary and hepatic histology, lipoperoxidation and antioxidant activity of lung tissue, alveolar-arterial O2 difference and lung / body weight ratio (%) were evaluated. Results: When comparing the groups, could be observed an increase of vasodilation and pulmonary fibrosis in the BDL group and the reduction of this in relation to the BDL + MEL group. It was also observed significant changes in the activity of catalase, ApCO2, ApO2 in the LBD group when compared to the other groups. Conclusion: The use of MEL has been shown to be effective in reducing vasodilation, fibrosis levels and oxidative stress as well as gas exchange in an experimental HPS model.

RESUMO Objetivo: Avaliar as alterações pulmonares de animais com Síndrome Hepatopulmonar (SHP), submetidos à ligadura de ducto biliar (LDB), bem como o efeito antioxidante da Melatonina (MEL). Métodos: Dezesseis ratos machos da espécie Wistar, divididos em quatro grupos: Sham, Grupo LDB, Grupo Sham + MEL e LDB + MEL. Foram avaliadas a histologia pulmonar e hepática, a lipoperoxidação e atividade antioxidante do tecido pulmonar, diferença álveolo-arterial de O2 e relação peso pulmonar/peso corporal (%). Resultados: Quando comparados os grupos, observamos um aumento da vasodilatação e fibrose pulmonar no grupo LDB e a redução deste em relação ao grupo LDB+MEL. Observamos ainda alterações significativas na atividade da catalase, PaCO2, PaO2 no grupo LBD quando comparado aos demais grupos. Conclusões: A utilização da MEL demonstrou-se eficaz na redução da vasodilatação, níveis de fibrose e estresse oxidativo assim como na troca gasosa em modelo experimental de SHP.

A subclinical high tricuspid regurgitation pressure gradient independent of the mean pulmonary artery pressure is a risk factor for the survival after living donor liver transplantation.

BACKGROUND: Portopulmonary hypertension (POPH) is characterized by pulmonary vasoconstriction, while hepatopulmonary syndrome (HPS) is characterized by vasodilation. Definite POPH is a risk factor for the survival after orthotopic liver transplantation (OLT), as the congestive pressure affects the grafted liver, while subclinical pulmonary hypertension (PH) has been acknowledged as a non-risk factor for deceased donor OLT. Given that PH measurement requires cardiac catheterization, the tricuspid regurgitation pressure gradient (TRPG) measured by echocardiography is used to screen for PH and congestive pressure to the liver. We investigated the impact of a subclinical high TRPG on the survival of small grafted living donor liver transplantation (LDLT). METHODS: We retrospectively analyzed 84 LDLT candidates. Patients exhibiting a TRPG ≥25 mmHg on echocardiography were categorized as potentially having liver congestion (subclinical high TRPG; n = 34). The mean pulmonary artery pressure (mPAP) measured after general anesthesia with FIO20.6 (mPAP-FIO20.6) was also assessed. Patients exhibiting pO2 < 80 mmHg and an alveolar-arterial oxygen gradient (AaDO2) ≥ 15 mmHg were categorized as potentially having HPS (subclinical HPS; n = 29). The clinical course after LDLT was investigated according to subclinical high TRPG. RESULTS: A subclinical high TRPG (p = 0.012) and older donor age (p = 0.008) were correlated with a poor 40-month survival. Although a higher mPAP-FIO20.6 was expected to correlate with a worse survival, a high mPAP-FIO20.6 with a low TRPG was associated with high frequency complicating subclinical HPS and a good survival, suggesting a reduction in the PH pressure via pulmonary shunt. CONCLUSION: In cirrhosis patients, mPAP-FIO20.6 may not accurately reflect the congestive pressure to the liver, as the pressure might escape via pulmonary shunt. A subclinical high TRPG is an important marker for predicting a worse survival after LDLT, possibly reflecting congestive pressure to the grafted small liver.

Potential Clinical Targets in Hepatopulmonary Syndrome: Lessons From Experimental Models.

Hepatopulmonary syndrome (HPS) is a relatively common and potentially severe pulmonary complication of cirrhosis with increased risk of mortality. In experimental models, a complex interaction between pulmonary endothelial cells, monocytes, and the respiratory epithelium, which produces chemokines, cytokines, and angiogenic growth factors, causes alterations in the alveolar microvasculature, resulting in impaired oxygenation. Model systems are critical for evaluating mechanisms and for preclinical testing in HPS, due to the challenges of evaluating the lung in the setting of advanced liver disease in humans. This review provides an overview of current knowledge and recent findings in the rodent common bile duct ligation model of HPS, which recapitulates many features of human disease. We focus on the concepts of endothelial derangement, monocyte infiltration, angiogenesis, and alveolar type II cell dysfunction as main contributors and potential targets for therapy.