The prevalence and severity of metabolic dysfunction–associated steatotic liver disease (MASLD) are increasing. Physicians who treat patients with MASLD may acknowledge the strong coincidence with... Show moreThe prevalence and severity of metabolic dysfunction–associated steatotic liver disease (MASLD) are increasing. Physicians who treat patients with MASLD may acknowledge the strong coincidence with cardiometabolic disease, including atherosclerotic cardiovascular disease (asCVD). This raises questions on co-occurrence, causality, and the need for screening and multidisciplinary care for MASLD in patients with asCVD, and vice versa. Here, we review the interrelations of MASLD and heart disease and formulate answers to these matters. Epidemiological studies scoring proxies for atherosclerosis and actual cardiovascular events indicate increased atherosclerosis in patients with MASLD, yet no increased risk of asCVD mortality. MASLD and asCVD share common drivers: obesity, insulin resistance and type 2 diabetes mellitus (T2DM), smoking, hypertension, and sleep apnea syndrome. In addition, Mendelian randomization studies support that MASLD may cause atherosclerosis through mixed hyperlipidemia, while such evidence is lacking for liver-derived procoagulant factors. In the more advanced fibrotic stages, MASLD may contribute to heart failure with preserved ejection fraction by reduced filling of the right ventricle, which may induce fatigue upon exertion, often mentioned by patients with MASLD. Some evidence points to an association between MASLD and cardiac arrhythmias. Regarding treatment and given the strong co-occurrence of MASLD and asCVD, pharmacotherapy in development for advanced stages of MASLD would ideally also reduce cardiovascular events, as has been demonstrated for T2DM treatments. Given the common drivers, potential causal factors and especially given the increased rate of cardiovascular events, comprehensive cardiometabolic risk management is warranted in patients with MASLD, preferably in a multidisciplinary approach. Show less
Zwol, W. van; Rimbert, A.; Wolters, J.C.; Smit, M.; Bloks, V.W.; Kloosterhuis, N.J.; ... ; Kuivenhoven, J.A. 2022
The assembly and secretion of VLDL from the liver, a pathway that affects hepatic and plasma lipids, remains incompletely understood. We set out to identify players in the VLDL biogenesis pathway... Show moreThe assembly and secretion of VLDL from the liver, a pathway that affects hepatic and plasma lipids, remains incompletely understood. We set out to identify players in the VLDL biogenesis pathway by identifying genes that are co-expressed with the MTTP gene that encodes for microsomal triglyceride transfer protein, key to the lipidation of apolipoprotein B, the core protein of VLDL. Using human and murine transcriptomic data sets, we identified small leucine-rich protein 1 (SMLR1), encoding for small leucine-rich protein 1, a protein of unknown function that is exclusively expressed in liver and small intestine. To assess the role of SMLR1 in the liver, we used somatic CRISPR/CRISPR-associated protein 9 gene editing to silence murine Smlr1 in hepatocytes (Smlr1-LKO). When fed a chow diet, male and female mice show hepatic steatosis, reduced plasma apolipoprotein B and triglycerides, and reduced VLDL secretion without affecting microsomal triglyceride transfer protein activity. Immunofluorescence studies show that SMLR1 is in the endoplasmic reticulum and Cis-Golgi complex. The loss of hepatic SMLR1 in female mice protects against diet-induced hyperlipidemia and atherosclerosis but causes NASH. On a high-fat, high-cholesterol diet, insulin and glucose tolerance tests did not reveal differences in male Smlr1-LKO mice versus controls. We propose a role for SMLR1 in the trafficking of VLDL from the endoplasmic reticulum to the Cis-Golgi complex. While this study uncovers SMLR1 as a player in the VLDL assembly, trafficking, and secretion pathway, it also shows that NASH can occur with undisturbed glucose homeostasis and atheroprotection. Show less
Background and Aims: In hereditary hemorrhagic telangiectasia (HHT), severe liver vascular malformations are associated with mutations in the Activin A Receptor-Like Type 1 (ACVRL1) gene encoding... Show moreBackground and Aims: In hereditary hemorrhagic telangiectasia (HHT), severe liver vascular malformations are associated with mutations in the Activin A Receptor-Like Type 1 (ACVRL1) gene encoding ALK1, the receptor for bone morphogenetic protein (BMP) 9/BMP10, which regulates blood vessel development. Here, we established an HHT mouse model with exclusive liver involvement and adequate life expectancy to investigate ALK1 signaling in liver vessel formation and metabolic function. Approach and Results: Liver sinusoidal endothelial cell (LSEC)-selective Cre deleter line, Stab2-iCreF3, was crossed with Acvrl1-floxed mice to generate LSEC-specific Acvrl1-deficient mice (Alk1(HEC-KO)). Alk1(HEC-KO) mice revealed hepatic vascular malformations and increased posthepatic flow, causing right ventricular volume overload. Transcriptomic analyses demonstrated induction of proangiogenic/tip cell gene sets and arterialization of hepatic vessels at the expense of LSEC and central venous identities. Loss of LSEC angiokines Wnt2, Wnt9b, and R-spondin-3 (Rspo3) led to disruption of metabolic liver zonation in Alk1(HEC-KO) mice and in liver specimens of patients with HHT. Furthermore, prion-like protein doppel (Prnd) and placental growth factor (Pgf) were upregulated in Alk1(HEC-KO) hepatic endothelial cells, representing candidates driving the organ-specific pathogenesis of HHT. In LSEC in vitro, stimulation or inhibition of ALK1 signaling counter-regulated Inhibitors of DNA binding (ID)1-3, known Alk1 transcriptional targets. Stimulation of ALK1 signaling and inhibition of ID1-3 function confirmed regulation of Wnt2 and Rspo3 by the BMP9/ALK1/ID axis. Conclusions: Hepatic endothelial ALK1 signaling protects from development of vascular malformations preserving organ-specific endothelial differentiation and angiocrine signaling. The long-term surviving Alk1(HEC-KO) HHT model offers opportunities to develop targeted therapies for this severe disease. Show less
Background: NAFLD affects nearly 25% of the global population. Cardiovascular disease (CVD) is the most common cause of death among patients with NAFLD, in line with highly prevalent dyslipidemia... Show moreBackground: NAFLD affects nearly 25% of the global population. Cardiovascular disease (CVD) is the most common cause of death among patients with NAFLD, in line with highly prevalent dyslipidemia in this population. Increased plasma triglyceride (TG)-rich lipoprotein (TRL) concentrations, an important risk factor for CVD, are closely linked with hepatic TG content. Therefore, it is of great interest to identify regulatory mechanisms of hepatic TRL production and remnant uptake in the setting of hepatic steatosis.Approach and Results: To identify liver-regulated pathways linking intrahepatic and plasma TG metabolism, we performed transcriptomic analysis of liver biopsies from two independent cohorts of obese patients. Hepatic encoding apolipoprotein F (APOF) expression showed the fourth-strongest negatively correlation with hepatic steatosis and the strongest negative correlation with plasma TG levels. The effects of adenoviral-mediated human ApoF (hApoF) overexpression on plasma and hepatic TG were assessed in C57BL6/J mice. Surprisingly, hApoF overexpression increased both hepatic very low density lipoprotein (VLDL)-TG secretion and hepatic lipoprotein remnant clearance, associated a similar to 25% reduction in plasma TG levels. Conversely, reducing endogenous ApoF expression reduced VLDL secretion in vivo, and reduced hepatocyte VLDL uptake by similar to 15% in vitro. Transcriptomic analysis of APOF-overexpressing mouse livers revealed a gene signature related to enhanced ApoB-lipoprotein clearance, including increased expression of Ldlr and Lrp1, among others.Conclusion: These data reveal a previously undescribed role for ApoF in the control of plasma and hepatic lipoprotein metabolism by favoring VLDL-TG secretion and hepatic lipoprotein remnant particle clearance. Show less
Erken, R.; Loukachov, V.; Dort, K.; Hurk, A. den; Takkenberg, R.B.; Niet, A.; ... ; Kootstra, N. 2022
Background and Aims: HBV can integrate in the host genome of the hepat-ocyte and recent findings suggest that integrated HBV contributes to the per-sistent production of viral proteins. Here, we... Show moreBackground and Aims: HBV can integrate in the host genome of the hepat-ocyte and recent findings suggest that integrated HBV contributes to the per-sistent production of viral proteins. Here, we quantified the levels of integratedHBV in patients with chronic hepatitis B (CHB) and analyzed the relation be-tween HBV integration, virological activity (plasma HBV DNA and HBsAg lev-els), and clinical outcomes.Approach and Results: We developed and validated a multistep Arthrobacterluteus (Alu)- PCR that specifically amplifies integrated HBV and RT-Alu- PCRdetecting mRNA transcripts derived from integrated HBV. Pretreatment liverbiopsy samples and baseline characteristics of 124 patients with CHB eithertreated for 48 weeks with pegylated interferon plus adefovir or tenofovir or re-ceiving no treatment were available for analysis. Integrated HBV sequencescontaining open reading frame S and X (but not C) and S and X mRNA tran-scripts derived from integrated HBV could be detected and quantified in liverbiopsies. Integrated HBV levels correlated with HBV DNA, HBsAg, alanineaminotransferase plasma levels, and the liver histology activity index but notto levels of intrahepatic covalently closed circular DNA (cccDNA), plasmapregenomic RNA, or hepatitis B core-related antigen. Multivariable logisticregression analysis showed that lower baseline HBV integration levels wereindependently associated with HBsAg loss (functional cure) within 5 yearsfollow-up.Conclusions: Integrated HBV levels are strongly correlated with surrogatemarkers for virological activity but not to cccDNA levels and are predictivefor HBsAg loss. Our data suggest that integrated HBV is closely related toHBV replication and may therefore be an important tool in the evaluation anddevelopment of treatment modalities aiming to cure CHB. Show less
Background and Aims In patients with acute liver failure (ALF) who suffer from massive hepatocyte loss, liver progenitor cells (LPCs) take over key hepatocyte functions, which ultimately determines... Show moreBackground and Aims In patients with acute liver failure (ALF) who suffer from massive hepatocyte loss, liver progenitor cells (LPCs) take over key hepatocyte functions, which ultimately determines survival. This study investigated how the expression of hepatocyte nuclear factor 4 alpha (HNF4 alpha), its regulators, and targets in LPCs determines clinical outcome of patients with ALF. Approach and Results Clinicopathological associations were scrutinized in 19 patients with ALF (9 recovered and 10 receiving liver transplantation). Regulatory mechanisms between follistatin, activin, HNF4 alpha, and coagulation factor expression in LPC were investigated in vitro and in metronidazole-treated zebrafish. A prospective clinical study followed up 186 patients with cirrhosis for 80 months to observe the relevance of follistatin levels in prevalence and mortality of acute-on-chronic liver failure. Recovered patients with ALF robustly express HNF4 alpha in either LPCs or remaining hepatocytes. As in hepatocytes, HNF4 alpha controls the expression of coagulation factors by binding to their promoters in LPC. HNF4 alpha expression in LPCs requires the forkhead box protein H1-Sma and Mad homolog 2/3/4 transcription factor complex, which is promoted by the TGF-beta superfamily member activin. Activin signaling in LPCs is negatively regulated by follistatin, a hepatocyte-derived hormone controlled by insulin and glucagon. In contrast to patients requiring liver transplantation, recovered patients demonstrate a normal activin/follistatin ratio, robust abundance of the activin effectors phosphorylated Sma and Mad homolog 2 and HNF4 alpha in LPCs, leading to significantly improved coagulation function. A follow-up study indicated that serum follistatin levels could predict the incidence and mortality of acute-on-chronic liver failure. Conclusions These results highlight a crucial role of the follistatin-controlled activin-HNF4 alpha-coagulation axis in determining the clinical outcome of massive hepatocyte loss-induced ALF. The effects of insulin and glucagon on follistatin suggest a key role of the systemic metabolic state in ALF. Show less
Background and Aims The United Network for Organ Sharing's Model for End-Stage Liver Disease (UNOS-MELD) score is the basis of liver allocation in the Eurotransplant region. It was constructed 20... Show moreBackground and Aims The United Network for Organ Sharing's Model for End-Stage Liver Disease (UNOS-MELD) score is the basis of liver allocation in the Eurotransplant region. It was constructed 20 years ago in a small US cohort and has remained unchanged ever since. The best boundaries and coefficients were never calculated for any region outside the United States. Therefore, this study refits the MELD (reMELD) for the Eurotransplant region.Approach and Results All adult patients listed for a first liver transplantation between January 1, 2007, and December 31, 2018, were included. Data were randomly split in a training set (70%) and a validation set (30%). In the training data, generalized additive models with splines were plotted for each MELD parameter. The lower and upper bound combinations with the maximum log-likelihood were chosen for the final models. The refit models were tested in the validation data with C-indices and Brier scores. Through likelihood ratio tests the refit models were compared to UNOS-MELD. The correlation between scores and survival of prioritized patients was calculated. A total of 6,684 patients were included. Based on training data, refit parameters were capped at creatinine 0.7-2.5, bilirubin 0.3-27, international normalized ratio 0.1-2.6, and sodium 120-139. ReMELD and reMELD-Na showed C-indices of 0.866 and 0.869, respectively. ReMELD-Na prioritized patients with 1.6 times higher 90-day mortality probabilities compared to UNOS-MELD.Conclusions Refitting MELD resulted in new lower and upper bounds for each parameter. The predictive power of reMELD-Na was significantly higher than UNOS-MELD. ReMELD prioritized patients with higher 90-day mortality rates. Thus, reMELD(-Na) should replace UNOS-MELD for liver graft allocation in the Eurotransplant region. Show less
Background and Aims Previous small studies have appraised the gut microbiome (GM) in steatosis, but large-scale studies are lacking. We studied the association of the GM diversity and composition,... Show moreBackground and Aims Previous small studies have appraised the gut microbiome (GM) in steatosis, but large-scale studies are lacking. We studied the association of the GM diversity and composition, plasma metabolites, predicted functional metagenomics, and steatosis.Approach and Results This is a cross-sectional analysis of the prospective population-based Rotterdam Study. We used 16S ribosomal RNA gene sequencing and determined taxonomy using the SILVA reference database. Alpha diversity and beta diversity were calculated using the Shannon diversity index and Bray-Curtis dissimilarities. Differences were tested across steatosis using permutational multivariate analysis of variance. Hepatic steatosis was diagnosed by ultrasonography. We subsequently selected genera using regularized regression. The functional metagenome was predicted based on the GM using Kyoto Encyclopedia of Genes and Genomes pathways. Serum metabolomics were assessed using high-throughput proton nuclear magnetic resonance. All analyses were adjusted for age, sex, body mass index, alcohol, diet, and proton-pump inhibitors. We included 1,355 participants, of whom 472 had steatosis. Alpha diversity was lower in steatosis (P = 1.1 center dot 10(-9)), and beta diversity varied across steatosis strata (P = 0.001). Lasso selected 37 genera of which three remained significantly associated after adjustment (Coprococcus3: beta = -65; Ruminococcus Gauvreauiigroup: beta = 62; and Ruminococcus Gnavusgroup: beta = 45, Q-value = 0.037). Predicted metagenome analyses revealed that pathways of secondary bile-acid synthesis and biotin metabolism were present, and D-alanine metabolism was absent in steatosis. Metabolic profiles showed positive associations for aromatic and branched chain amino acids and glycoprotein acetyls with steatosis and R. Gnavusgroup, whereas these metabolites were inversely associated with alpha diversity and Coprococcus3.Conclusions We confirmed, on a large-scale, the lower microbial diversity and association of Coprococcus and Ruminococcus Gnavus with steatosis. We additionally showed that steatosis and alpha diversity share opposite metabolic profiles. Show less
Roscam Abbing, R.L.P.; Slijepcevic, D.; Donkers, J.M.; Havinga, R.; Duijst, S.; Paulusma, C.C.; ... ; Graaf, S.F.J. van de 2019
Active secretion of bile salts into the canalicular lumen drives bile formation and promotes biliary cholesterol and phospholipid output. Disrupting hepatic bile salt uptake, by inhibition of... Show moreActive secretion of bile salts into the canalicular lumen drives bile formation and promotes biliary cholesterol and phospholipid output. Disrupting hepatic bile salt uptake, by inhibition of sodium‐taurocholate cotransporting polypetide (NTCP; Slc10a1) with Myrcludex B, is expected to limit bile salt flux through the liver and thereby to decrease biliary lipid excretion. Here, we show that Myrcludex B–mediated NTCP inhibition actually causes an increase in biliary cholesterol and phospholipid excretion whereas biliary bile salt output and bile salt composition remains unchanged. Increased lysosomal discharge into bile was excluded as a potential contributor to increased biliary lipid secretion. Induction of cholesterol secretion was not a consequence of increased ATP‐binding cassette subfamily G member 5/8 activity given that NTCP inhibition still promoted cholesterol excretion in Abcg8−/− mice. Stimulatory effects of NTCP inhibition were maintained in Sr‐b1−/− mice, eliminating the possibility that the increase in biliary lipids was derived from enhanced uptake of high‐density lipoprotein–derived lipids. NTCP inhibition shifts bile salt uptake, which is generally more periportally restricted, toward pericentral hepatocytes, as was visualized using a fluorescently labeled conjugated bile salt. As a consequence, exposure of the canalicular membrane to bile salts was increased, allowing for more cholesterol and phospholipid molecules to be excreted per bile salt. Conclusion: NTCP inhibition increases biliary lipid secretion, which is independent of alterations in bile salt output, biliary bile salt hydrophobicity, or increased activity of dedicated cholesterol and phospholipid transporters. Instead, NTCP inhibition shifts hepatic bile salt uptake from mainly periportal hepatocytes toward pericentral hepatocytes, thereby increasing exposure of the canalicular membrane to bile salts linking to increased biliary cholesterol secretion. This process provides an additional level of control to biliary cholesterol and phospholipid secretion. Show less
Claria, J.; Moreau, R.; Fenaille, F.; Amoros, A.; Junot, C.; Gronbaek, H.; ... ; Grifols Chair European Fdn Study C 2019
Current preclinical drug testing does not predict some forms of adverse drug reactions in humans. Efforts at improving predictability of drug-induced tissue injury in humans include using stem cell... Show moreCurrent preclinical drug testing does not predict some forms of adverse drug reactions in humans. Efforts at improving predictability of drug-induced tissue injury in humans include using stem cell technology to generate human cells for screening for adverse effects of drugs in humans. The advent of induced pluripotent stem cells means that it may ultimately be possible to develop personalized toxicology to determine interindividual susceptibility to adverse drug reactions. However, the complexity of idiosyncratic drug-induced liver injury means that no current single-cell model, whether of primary liver tissue origin, from liver cell lines, or derived from stem cells, adequately emulates what is believed to occur during human drug-induced liver injury. Nevertheless, a single-cell model of a human hepatocyte which emulates key features of a hepatocyte is likely to be valuable in assessing potential chemical risk; furthermore, understanding how to generate a relevant hepatocyte will also be critical to efforts to build complex multicellular models of the liver. Currently, hepatocyte-like cells differentiated from stem cells still fall short of recapitulating the full mature hepatocellular phenotype. Therefore, we convened a number of experts from the areas of preclinical and clinical hepatotoxicity and safety assessment, from industry, academia, and regulatory bodies, to specifically explore the application of stem cells in hepatotoxicity safety assessment and to make recommendations for the way forward. In this short review, we particularly discuss the importance of benchmarking stem cell-derived hepatocyte-like cells to their terminally differentiated human counterparts using defined phenotyping, to make sure the cells are relevant and comparable between labs, and outline why this process is essential before the cells are introduced into chemical safety assessment. (Hepatology 2017;65:710-721). Show less
Claria, J.; Stauber, R.E.; Coenraad, M.J.; Moreau, R.; Jalan, R.; Pavesi, M.; ... ; European Fdn Study CHRONIC Liver 2016
Acute-on-chronic liver failure (ACLF) in cirrhosis is characterized by acute decompensation (AD), organ failure(s), and high short-term mortality. Recently, we have proposed (systemic inflammation ... Show moreAcute-on-chronic liver failure (ACLF) in cirrhosis is characterized by acute decompensation (AD), organ failure(s), and high short-term mortality. Recently, we have proposed (systemic inflammation [SI] hypothesis) that ACLF is the expression of an acute exacerbation of the SI already present in decompensated cirrhosis. This study was aimed at testing this hypothesis and included 522 patients with decompensated cirrhosis (237 with ACLF) and 40 healthy subjects. SI was assessed by measuring 29 cytokines and the redox state of circulating albumin (HNA2), a marker of systemic oxidative stress. Systemic circulatory dysfunction (SCD) was estimated by plasma renin (PRC) and copeptin (PCC) concentrations. Measurements were performed at enrollment (baseline) in all patients and sequentially during hospitalization in 255. The main findings of this study were: (1) Patients with AD without ACLF showed very high baseline levels of inflammatory cytokines, HNA2, PRC, and PCC. Patients with ACLF showed significantly higher levels of these markers than those without ACLF; (2) different cytokine profiles were identified according to the type of ACLF precipitating event (active alcoholism/acute alcoholic hepatitis, bacterial infection, and others); (3) severity of SI and frequency and severity of ACLF at enrollment were strongly associated. The course of SI and the course of ACLF (improvement, no change, or worsening) during hospitalization and short-term mortality were also strongly associated; and (4) the strength of association of ACLF with SI was higher than with SCD. Conclusion: These data support SI as the primary driver of ACLF in cirrhosis. Show less
Schlegel, M.; Kohler, D.; Korner, A.; Granja, T.; Straub, A.; Giera, M.; Mirakaj, V. 2016
Hepatic ischemia/reperfusion (I/R) is a major adverse reaction to liver transplantation, hemorrhagic shock, or resection. Recently, the anti-inflammatory properties of the axonal guidance cue... Show moreHepatic ischemia/reperfusion (I/R) is a major adverse reaction to liver transplantation, hemorrhagic shock, or resection. Recently, the anti-inflammatory properties of the axonal guidance cue netrin-1 were reported. Here, we demonstrate that netrin-1 also impacts the resolution of inflammation and promotes hepatic repair and regeneration during liver I/R injury. In initial studies, we investigated the induction of netrin-1 and its receptors in murine liver tissues after I/R injury. Hepatic I/R injury was performed in mice with a partial genetic netrin-1 deficiency (Ntn1(+/-)) or wild-type C57BL/6 treated with exogenous netrin-1 to examine the endogenous and therapeutically administered impact of netrin-1. These investigations were corroborated by studies determining the characteristics of intravascular leukocyte flow, clearance of apoptotic neutrophils (polymorphonuclear cells [PMNs]), production of specialized proresolving lipid mediators (SPMs), generation of specific growth factors contributing to the resolution of inflammation, and liver repair. Hepatic I/R was associated with a significant reduction of netrin-1 transcript and protein in murine liver tissue. Subsequent studies in netrin-1-deficient mice revealed lower efficacies in reducing PMN infiltration, proinflammatory cytokine levels, and hepatic-specific injury enzymes. Conversely, mice treated with exogenous netrin-1 exhibited increased liver protection and repair, reducing neutrophil influx into the injury site, decreasing proinflammatory mediators, increasing efferocytosis of apoptotic PMNs, and stimulating local endogenous biosynthesis of SPMs and the generation of specific growth factors. Finally, genetic studies implicated the A2B adenosine receptor in netrin-1-mediated protection during hepatic I/R injury. Conclusion: The present study indicates a previously unrecognized role for netrin-1 in liver protection and its contribution to tissue homeostasis and regeneration. (Hepatology 2016;63:1689-1705) Show less
