Adipose Tissue Insulin Resistance Correlates with Disease Severity in Pediatric Metabolic Dysfunction-Associated Steatotic Liver Disease: A Prospective Cohort Study.

OBJECTIVES: To assess the role of adipose tissue insulin resistance (Adipo-IR) in the pathogenesis of pediatric metabolic dysfunction-associated steatotic liver disease (MASLD) and to determine Adipo-IR evolution during a lifestyle intervention program. STUDY DESIGN: In this prospective cohort study, children and adolescents with severe obesity were recruited between July 2020 and December 2022 at an inpatient pediatric rehabilitation center. Treatment consisted of dietary intervention and physical activity. Liver steatosis and fibrosis were evaluated using ultrasound examination and transient elastography with controlled attenuation parameter and liver stiffness measurement. Every 4-6 months, anthropometric measurements, serum biochemical analysis, ultrasound examination, and elastography were repeated. Adipo-IR was estimated by the product of the fasting serum insulin times the fasting free fatty acid concentration, and hepatic IR by the Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), respectively. RESULTS: Of 200 patients with obesity, 56% had evidence of steatosis on ultrasound examination and 26% were diagnosed with fibrosis (≥F2). Adipo-IR increased progressively from lean controls to patients with obesity to patients with MASLD and MASLD with fibrosis. Adipo-IR was already increased in patients with only mild steatosis (P = .0403). Patients with more insulin-sensitive adipose tissue exhibited a lower liver fat content (P < .05) and serum alanine transaminase levels (P = .001). Adipo-IR correlated positively with visceral adipose tissue weight, waist circumference, and the visceral adipose tissue/gynoid adipose tissue ratio (P < .001), but not with total body fat percentage (P = .263). After 4-6 months of lifestyle management, both MASLD and Adipo-IR improved. CONCLUSIONS: Our data suggest that Adipo-IR is associated with the presence of pediatric MASLD, particularly steatosis.

Systematic review: Glycomics as diagnostic markers for hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer with one of the highest cancer-related mortality rates worldwide. Early diagnosis is crucial for improving the therapeutic options and reducing the disease-related mortality. AIM: To investigate serum N-glycomics as diagnostic markers for HCC. METHODS: We performed a comprehensive search in PubMed, EMBASE, Web of Science and Scopus through August 17, 2023. Eligible studies assessed the potential use of serum N-glycomics as diagnostic biomarkers for HCC. Study selection, data extraction and quality assessment were performed by two independent reviewers. RESULTS: Of the 48 articles included, 11 evaluated the utility of N-glycomics for the diagnosis of HCC in whole serum while the remaining articles focused on specific protein glycoforms or protein levels. Of these specific proteins, haptoglobin, alpha-fetoprotein (AFP), kininogen (Kin), α-1-antitrypsin and Golgi protein 73 (GP73) were the most frequently studied. Increased levels of fucosylation and branching presented as the most prevalent post-translational modifications of glycoproteins in patients with HCC compared to controls. Notably, glycomics-based biomarkers may provide a clinical benefit for the diagnosis of early HCC, as several algorithms achieved AUCs between 0.92-0.97. However, these were based on single studies with limited sample sizes and should therefore be validated. CONCLUSIONS: Alterations in serum N-glycomics, characterised by increased levels of fucosylation and branching, have potential as diagnostic biomarkers for HCC. Optimisation of study design, patient selection and analysing techniques are needed before clinical implementation will be possible.

Patients hospitalized with alcohol-related liver disease and prior bariatric surgery are more prone to develop acute-on-chronic liver failure.

BACKGROUND & AIMS: Patients with a history of bariatric surgery (BS) are susceptible to developing alcohol use disorder. We and others have previously shown that these patients can develop severe alcohol-related liver disease (ARLD). Our aim was to describe the demographics, co-morbidities and mortality of a hospitalized population diagnosed with alcohol-related liver disease, in relation to BS. METHODS: We included 299 patients hospitalized with ARLD at the Ghent University Hospital between 1 January 2018 and 31 December 2022. Clinical, biochemical and outcome data were retrospectively retrieved from the most recent hospitalization. Statistical analysis was performed using the t test, Mann-Whitney U and χ2 tests. RESULTS: Thirteen per cent (39/299) of patients admitted with ARLD had a history of bariatric surgery, of whom 25 (64.1%) had undergone Roux-en-Y gastric bypass. Patients with a history of BS were predominantly female (76.9%), in contrast to the non-BS population (29.2%) (p < .0001), and despite being significantly younger (p < .0001) and had a similar survival (61.5% vs. 58.1%). Bariatric surgery and older age at diagnosis were both significantly associated with poorer transplant-free survival. The cause of death was acute-on-chronic liver failure in 73.3% of BS patients, compared to only 19.2% of those without a history of BS (p < .0001). The weekly amount of alcohol consumed (p = .012) and duration of use (p < .0001) were significantly lower/shorter in the BS population. CONCLUSIONS: BS patients hospitalized with ARLD are predominantly younger women with a lower cumulative alcohol consumption compared to those without prior BS. BS impacted transplant-free survival, with ACLF as the predominant cause of death in these patients.

Hepatopulmonary syndrome.

Hepatopulmonary syndrome (HPS) is a pulmonary vascular complication of liver disease, which adversely affects prognosis. The disease is characterised by intrapulmonary vascular dilatations and shunts, resulting in impaired gas exchange. A complex interaction between the liver, the gut and the lungs, predominately impacting pulmonary endothelial cells, immune cells and respiratory epithelial cells, is responsible for the development of typical pulmonary alterations seen in HPS. Liver transplantation is the only therapeutic option and generally reverses HPS. Since the implementation of the model for end-stage liver disease (MELD) standard exception policy, outcomes in patients with HPS have been significantly better than they were in the pre-MELD era. This review summarises current knowledge and highlights what's new regarding the diagnosis and management of HPS, and our understanding of pathogenesis based on experimental models and translational studies.

Metallothioneins alter macrophage phenotype and represent novel therapeutic targets for acetaminophen-induced liver injury.

Acetaminophen (APAP) intoxication is the foremost cause of drug-induced liver failure in developed countries. The only pharmacologic treatment option, N-acetylcysteine (NAC), is not effective for patients who are admitted too late and/or who have excessive liver damage, emphasizing the need for alternative treatment options. APAP intoxication results in hepatocyte death and release of danger signals, which further contribute to liver injury, in part by hepatic monocyte/macrophage infiltration and activation. Metallothionein (MT) 1 and 2 have important danger signaling functions and might represent novel therapeutic targets in APAP overdose. Therefore, we evaluated hepatic MT expression and the effect of anti-MT antibodies on the transcriptional profile of the hepatic macrophage population and liver injury following APAP overdose in mice. Hepatic MT expression was significantly induced in APAP-intoxicated mice and abundantly present in human livers. APAP intoxication in mice resulted in increased serum transaminase levels, extended necrotic regions on liver histology and induced expression of proinflammatory markers, which was significantly less pronounced in mice treated with anti-MT antibodies. Anti-MT antibody therapy attenuated proinflammatory macrophage polarization, as demonstrated by RNA sequencing analyses of isolated liver macrophages and in LPS-stimulated bone marrow-derived macrophages. Importantly, NAC and anti-MT antibodies were equally effective whereas administration of anti-MT antibody in combination with NAC exceeded the efficiency of both monotherapies in APAP-induced liver injury (AILI). We conclude that the neutralization of secreted MTs using a monoclonal antibody is a novel therapeutic strategy as mono- or add-on therapy for AILI. In addition, we provide evidence suggesting that MTs in the extracellular environment are involved in macrophage polarization.

Pulmonary Abnormalities in Liver Disease: Relevance to Transplantation and Outcome.

Pulmonary disease in liver cirrhosis and portal hypertension (PH) constitutes a challenging clinical scenario and may have important implications with regard to prognosis, liver transplantation (LT) candidacy, and post-LT outcome. Pre-LT evaluation should include adequate screening for pulmonary diseases that may occur concomitantly with liver disease as well as for those that may arise as a complication of end-stage liver disease and PH, given that either may jeopardize safe LT and successful outcome. It is key to discriminate those patients who would benefit from LT, especially pulmonary disorders that have been reported to resolve post-LT and are considered "pulmonary indications" for transplant, from those who are at increased mortality risk and in whom LT is contraindicated. In conclusion, in this article, we review the impact of several pulmonary disorders, including cystic fibrosis, alpha 1-antitrypsin deficiency, hereditary hemorrhagic telangiectasia, sarcoidosis, coronavirus disease 2019, asthma, chronic obstructive pulmonary disease, pulmonary nodules, interstitial lung disease, hepatic hydrothorax, hepatopulmonary syndrome, and portopulmonary hypertension, on post-LT survival, as well as the reciprocal impact of LT on the evolution of lung function.

Diagnosis of Hepatopulmonary Syndrome in a Large Integrated Health System.

BACKGROUND & AIMS: Data on the accuracy of the diagnosis of hepatopulmonary syndrome (HPS) in cirrhosis is limited. We evaluated the clinical characteristics of patients with International Classification of Diseases (ICD) codes for hepatopulmonary syndrome (HPS) in a large integrated health system. METHODS: A retrospective review of encounters was performed of all patients with ICD-9-CM and/or ICD-10-CM diagnosis of cirrhosis and HPS from 2014-2019 in a multi-state health system. Demographics and cardiopulmonary testing closest to the time of HPS diagnosis were recorded. HPS was defined using standard criteria. RESULTS: A total of 42,749 unique individuals with cirrhosis were identified. An ICD diagnosis of HPS was found in 194 patients (0.45%), of which 182 had clinically confirmed cirrhosis. 143 (78.5%) underwent contrast-enhanced transthoracic echocardiography, and 98 (54%) had delayed shunting. Among them, 61 patients had a documented arterial blood gas, with 53 showing abnormal oxygenation (A-a gradient of >15 mm Hg). 12 were excluded due to significant pulmonary function test abnormalities and abnormal oxygenation from other cardiopulmonary diseases. Ultimately, 41 (22.5%) fulfilled the criteria for HPS. When stratifying those with an ICD code diagnosis of HPS into HPS, no HPS and indeterminate HPS groups, based on standard diagnostic criteria for HPS, we found that the confirmed HPS patients had similar complications except for less portopulmonary hypertension, worse gas exchange, less cardiopulmonary disease and were more often diagnosed in transplant centers. CONCLUSIONS: The diagnosis of HPS by ICD code is made in an extremely small subset of a sizeable cirrhotic cohort. When made, only a minority of these patients meet diagnostic criteria. Our findings highlight the need for improved education and more effective screening algorithms.

Myeloid-specific IRE1alpha deletion reduces tumour development in a diabetic, non-alcoholic steatohepatitis-induced hepatocellular carcinoma mouse model.

BACKGROUND AND AIMS: Obesity, diabetes and associated non-alcoholic steatohepatitis (NASH) are rising risk factors for hepatocellular carcinoma (HCC). Macrophages are important immune cells involved in inflammation and tumour development. Macrophage inositol-requiring enzyme 1 alpha (IRE1α), an ER-stress protein, has been shown to be involved in macrophage cytokine production, and myeloid-specific IRE1α knock-out (myeloid IRE1α-KO) mice showed reduced weight gain during high-fat diet feeding. However, the effect of myeloid IRE1α on NASH and subsequent HCC development has not been examined. Here, we characterized the transcriptional profile of the hepatic macrophage population in a diabetes-NASH-HCC mouse model, and investigated the effect of myeloid-specific IRE1α deletion on the phenotype of hepatic macrophage subsets and experimental NASH-HCC development. METHODS: Mice with non-functional myeloid IRE1α were created by crossing Ire1a floxed mice with Lysm-Cre mice. Two-day old myeloid IRE1α-KO and wild type (WT) mice were subcutaneously injected with streptozotocin (STZ), and male mice were fed a high-fat, -sucrose, -cholesterol diet (Western diet, WD) from the age of 4 weeks until 21 weeks. Control myeloid IRE1α-KO and WT mice received a PBS injection and were fed a matched control diet. These mice were evaluated for obesity, diabetes, NASH and HCC. The hepatic macrophage population was evaluated by flow cytometry and RNA sequencing on FACS-isolated macrophage subsets. RESULTS: STZ-injection and WD feeding resulted in an impaired glucose tolerance, advanced NASH with fibrosis, and HCC development. Myeloid IRE1α-KO STZ mice showed lower fasting glucose levels at the start of WD feeding, and an improved glucose tolerance and attenuated HCC development after 17 weeks of WD feeding despite a similar degree of liver steatosis and inflammation compared to WT mice. Transcriptomic analysis of WT liver Kupffer cells, macrophages and monocytes revealed phenotypical changes in those cell subsets during NASH-HCC development. Isolated liver Kupffer cells and macrophages from mice with a myeloid IRE1α deletion showed downregulated pathways involved in immune system activation and metabolic pathways (only in Kupffer cells), whereas pathways involved in cell division and metabolism were upregulated in monocytes. These transcriptional differences were attenuated during NASH-HCC development. CONCLUSION: Our results show that myeloid-specific IRE1α deletion results in an altered transcriptional profile of hepatic macrophages and dampens diabetes-induced NASH-HCC development, possibly by attenuated diabetes induction.

Vasomodulators and Liver Transplantation for Portopulmonary Hypertension: Evidence From a Systematic Review and Meta-Analysis.

BACKGROUND AND AIMS: Untreated portopulmonary hypertension (PoPH) carries a poor prognosis. Previous reports have described vasomodulator (VM) therapy and liver transplantation (LT) as treatment options. We aimed to provide summary estimates on the endpoints of pulmonary hemodynamics and survival in patients with PoPH, treated with different modalities. APPROACH AND RESULTS: We performed a systematic review with meta-analysis of mainly observational and case-control studies describing no treatment, VM, LT, or VM + LT in patients with PoPH. Twenty-six studies (1,019 patients) were included. Both VM and VM + LT improve pulmonary hemodynamics. A substantial proportion of patients treated with VM become eligible for LT (44%; 95% confidence interval [CI], 31-58). Pooled estimates for 1-, and 3-year postdiagnosis survival in patients treated with VM were 86% (95% CI, 81-90) and 69% (95% CI, 50-84) versus 82% (95% CI, 52-95) and 67% (95% CI, 53-78) in patients treated with VM + LT. Of note, studies reporting on the effect of VM mainly included Child-Pugh A/B patients, whereas studies reporting on VM + LT mainly included Child-Pugh B/C. Seven studies (238 patients) included both patients who received VM only and patients who received VM + LT. Risk of death in VM-only-treated patients was significantly higher than in patients who could be transplanted as well (odds ratio, 3.5; 95% CI, 1.4-8.8); however, importantly, patients who proceeded to transplant had been selected very strictly. In 50% of patients, VM can be discontinued post-LT (95% CI, 38-62). CONCLUSIONS: VM and VM + LT both improve pulmonary hemodynamics and prognosis in PoPH. In a strictly selected subpopulation of cases where LT is indicated based on severe liver disease and where LT is considered safe and feasible, treatment with VM + LT confers a better prognosis. Considering successful VM, 44% can proceed to LT, with half being able to postoperatively stop medication.

Combination of sivelestat and N-acetylcysteine alleviates the inflammatory response and exceeds standard treatment for acetaminophen-induced liver injury.

Hepatocyte death during acetaminophen (APAP) intoxication elicits a reactive inflammatory response, with hepatic recruitment of neutrophils and monocytes, which further aggravates liver injury. Neutrophil elastase (NE), secreted by activated neutrophils, carries degradative and cytotoxic functions and maintains a proinflammatory state. We investigated NE as a therapeutic target in acetaminophen-induced liver injury (AILI). C57BL/6 mice were administered a toxic dose of APAP, 2 h prior to receiving the NE inhibitor sivelestat, N-acetylcysteine (NAC), or a combination therapy, and were euthanized after 24 and 48 h. Upon APAP overdose, neutrophils and monocytes infiltrate the injured liver, accompanied by increased levels of NE. Combination therapy of NAC and sivelestat significantly limits liver damage, as evidenced by lower serum transaminase levels and less hepatic necrosis compared to mice that received APAP only, and this to a greater extent than NAC monotherapy. Lower hepatic expression of proinflammatory markers was observed in the combination treatment group, and flow cytometry revealed significantly less monocyte influx in livers from mice treated with the combination therapy, compared to untreated mice and mice treated with NAC only. The potential of NE to induce leukocyte migration was confirmed in vitro. Importantly, sivelestat did not impair hepatic repair. In conclusion, combination of NE inhibition with sivelestat and NAC dampens the inflammatory response and reduces liver damage following APAP overdose. This strategy exceeds the standard of care and might represent a novel therapeutic option for AILI.

Angiopoietin-2 Promotes Pathological Angiogenesis and Is a Therapeutic Target in Murine Nonalcoholic Fatty Liver Disease.

Angiogenesis contributes to the development of nonalcoholic steatohepatitis (NASH) and promotes inflammation, fibrosis, and progression to hepatocellular carcinoma (HCC). Angiopoietin-2 (Ang-2) is a key regulator of angiogenesis. We aimed to investigate the role of Ang-2 and its potential as a therapeutic target in NASH using human samples, in vivo mouse models, and in vitro assays. Serum Ang-2 levels were determined in 104 obese patients undergoing bariatric surgery and concomitant liver biopsy. The effect of the Ang-2/Tie2 receptor inhibiting peptibody L1-10 was evaluated in the methionine-choline deficient (MCD) and streptozotocin-western diet nonalcoholic fatty liver disease mouse models, and in vitro on endothelial cells and bone marrow-derived macrophages. The hepatic vasculature was visualized with µCT scans and scanning electron microscopy of vascular casts. Serum Ang-2 levels were increased in patients with histological NASH compared with patients with simple steatosis and correlated with hepatic CD34 immunoreactivity as a marker of hepatic angiogenesis. Serum and hepatic Ang-2 levels were similarly increased in mice with steatohepatitis. Both preventive and therapeutic L1-10 treatment reduced hepatocyte ballooning and fibrosis in MCD diet-fed mice and was associated with reduced hepatic angiogenesis and normalization of the vascular micro-architecture. Liver-isolated endothelial cells and monocytes from MCD-fed L1-10-treated mice showed reduced expression of leukocyte adhesion and inflammatory markers, respectively, compared with cells from untreated MCD diet-fed mice. In the streptozotocin-western diet model, therapeutic Ang-2 inhibition was able to reverse NASH and attenuate HCC progression. In vitro, L1-10 treatment mitigated increased cytokine production in lipopolysaccharide-stimulated endothelial cells but not in macrophages. Conclusion: Our findings provide evidence for Ang-2 inhibition as a therapeutic strategy to target pathological angiogenesis in NASH.

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.

Placental growth factor inhibition targets pulmonary angiogenesis and represents a therapy for hepatopulmonary syndrome in mice.

Hepatopulmonary syndrome (HPS) is a severe complication of cirrhosis with increased risk of mortality. Pulmonary microvascular alterations are key features of HPS; but underlying mechanisms are incompletely understood, and studies on HPS are limited to rats. Placental growth factor (PlGF), a proangiogenic molecule that is selectively involved in pathological angiogenesis, may play an important role in HPS development; however, its role has never been investigated. In this study, we validated an HPS model by common bile duct ligation (CBDL) in mice, investigated the kinetic changes in pulmonary angiogenesis and inflammation during HPS development, and provide evidence for a novel therapeutic strategy by targeting pathological angiogenesis. Mice with CBDL developed hypoxemia and intrapulmonary shunting on a background of liver fibrosis. Pulmonary alterations included increased levels of proangiogenic and inflammatory markers, which was confirmed in serum of human HPS patients. Increased PlGF production in HPS mice originated from alveolar type II cells and lung macrophages, as demonstrated by immunofluorescent staining. Dysfunctional vessel formation in CBDL mice was visualized by microscopy on vascular corrosion casts. Both prophylactic and therapeutic anti-PlGF (αPlGF) antibody treatment impeded HPS development, as demonstrated by significantly less intrapulmonary shunting and improved gas exchange. αPlGF treatment decreased endothelial cell dysfunction in vivo and in vitro and was accompanied by reduced pulmonary inflammation. Importantly, αPlGF therapy did not affect liver alterations, supporting αPlGF's ability to directly target the pulmonary compartment. CONCLUSION: CBDL in mice induces HPS, which is mediated by PlGF production; αPlGF treatment improves experimental HPS by counteracting pulmonary angiogenesis and might be an attractive therapeutic strategy for human HPS. (Hepatology 2017).

Non-alcoholic steatohepatitis induces transient changes within the liver macrophage pool.

Kupffer cells (KCs) and monocyte-derived macrophages are implicated in non-alcoholic steatohepatitis (NASH) pathogenesis but their functions remain unclear due to the lack of specific markers to distinguish between the different cell types. Additionally, it is unclear if multiple subsets of KCs are present during NASH. Here, we characterized the liver macrophage subsets during methionine/choline deficient (MCD) diet-induced NASH and recovery. We observed a significant reduced contribution of Ly6CloClec4F+Tim4+KCs to the hepatic macrophage pool in MCD fed mice, which normalized during recovery. Ly6CloClec4F-Tim4- monocyte-derived macrophages increased during MCD feeding and returned to baseline during recovery. Ly6CloClec4F+Tim4- monocyte-derived KCs developed during initial recovery but did not self-renew as their numbers were reduced after full recovery. Initial recovery from MCD diet feeding was further characterized by increased proportions of Ki-67+ proliferating KCs. In conclusion, the hepatic macrophage pool undergoes substantial albeit transient changes during NASH and recovery, with the KC pool being maintained by proliferation and differentiation of short-lived monocyte-derived KCs.