Serum vascular cell adhesion molecule-1 predicts significant liver fibrosis in non-alcoholic fatty liver disease

Serum Vascular Adhesion Protein-1 and Endothelial Dysfunction in Hepatic Cirrhosis: Searching for New Prognostic Markers

Endothelial dysfunction plays a key role in the development of liver cirrhosis. Among the biomarkers of endothelial dysfunction, the soluble form of Vascular Adhesion Protein-1 (sVAP-1) is an unconventional and less known adhesion molecule endowed also with amine oxidase activity. The aim of this study was to explore and correlate the behavior of sVAP-1 with that of the soluble vascular cell adhesion molecule-1 (sVCAM-1) and intercellular adhesion molecule-1 (sICAM-1) and with the severity of liver cirrhosis. A cross-sectional study was carried out by enrolling 28 controls, 59 cirrhotic patients without hepatocellular carcinoma, and 56 patients with hepatocellular carcinoma (HCC), mainly caused by alcohol abuse. The levels of adhesion molecules and of the pro-inflammatory cytokines (IL-6 and TNF-αα) were determined by immunoassay and the enzymatic activity of sVAP-1 by a fluorometric assay. In non-diabetic patients without HCC, a specific behavior of sVAP-1 was highlighted. Differently from sVCAM-1, sICAM-1, and cytokines, the sVAP-1 level was significantly increased only in the early stage of disease, and then, it decreased in the last stage (866 ± 390 ng/mL vs. 545 ± 316 ng/mL, in Child-Pugh class A vs. C, respectively, p < 0.05). Bivariate analysis correlates sVAP-1 to sVCAM-1, in the absence of HCC (Spearman's rho = 0.403, p < 0.01). Multiple linear regression analysis revealed that sVCAM-1 appears to be a predictor of sVAP-1 (β coefficient = 0.374, p = 0.021). In conclusion, in non-diabetic and non-HCC cirrhotic patients, sVAP-1 may be a potential prognostic biomarker that, together with sVCAM-1 and pro-inflammatory cytokines, may provide information on the progression of sinusoidal liver endothelium damage.

Yohimbine ameliorates liver inflammation and fibrosis by regulating oxidative stress and Wnt/β-catenin pathway

BACKGROUND AND PURPOSE

Chronic liver injury, caused by various aetiologies, causes recurrent tissue damage, culminating in decreased liver regenerative ability and resulting in fibrosis followed by cirrhosis. In this study, the anti-fibrotic activity of Yohimbine hydrochloride (YHC) was investigated using various in vitro models and in vivo models.

METHODS

To assess the anti-inflammatory, antioxidant, and anti-fibrotic effects of YHC, lipopolysaccharide or TGF-β induced differentiation or lipid-induced oxidative-stress models were employed using HLECs, HSC-LX2, and HepG2 cells. Further, thioacetamide (TAA) induced hepatic inflammation/fibrosis models were utilized to validate the YHC's anti-fibrotic activity in rats.

RESULTS

Inflammation/differentiation experiments in HLECs and HSC-LX2 revealed that YHC treatment significantly (p < 0.001) mitigated the lipopolysaccharide or TGF-β induced upregulation of inflammatory and fibrotic markers expression respectively. In addition, YHC dose-dependently reduced the TGF-β induced migration and palmitic acid-induced oxidative stress in HepG2 cells. Further, TAA administration (5 weeks) in vivo rat model showed increased inflammatory marker levels/expression, oxidative stress, and pathological abnormalities. Additionally, TAA administration (9 weeks) elevated the fibrotic marker expression, collagen deposition in liver tissues, and shortened longevity in rats. Treatment with YHC dose-dependently mitigated the TAA-induced abnormalities in both inflammation and fibrosis models and improved the survival of the rats. Further mechanistic approaches revealed that TAA administration elevated the JNK, Wnt components and β-catenin expression in hepatic stellate cells and animal tissues. Further treatment with YHC significantly modulated the JNK/Wnt/β-catenin signaling. Moreover, the β-catenin nuclear translocation results showed that β-catenin levels were significantly elevated in the nuclear fraction of TAA control samples and reduced in YHC-treated samples.

CONCLUSION

Yohimbine treatment significantly improved inflammation and fibrosis by inhibiting differentiation, oxidative stress, and collagen deposition by partly modulating the JNK/Wnt/β-catenin pathway. These results might serve as a foundation for proposing yohimbine as a potential lead compound for liver fibrosis.

Hepatic stellate cells activate and avoid death under necroptosis stimuli: Hepatic fibrosis during necroptosis

BACKGROUND AND AIM

Necroptosis is an emerging cell death pathway that allows cells to undergo "cellular suicide" in a caspase-independent manner. We investigated the fate of hepatic stellate cells (HSCs) under necroptotic stimuli.

METHODS AND RESULTS

The RNA level of mixed lineage kinase domain-like protein (MLKL) is higher in patients with non-alcoholic fatty liver disease than in healthy controls. Hepatic fibrosis was significantly lower in MLKL-KO bile duct ligation (KO-BDL) mice than in wild-type-BDL mice. Necroptotic stimuli caused the death of HT-29 and U937 cells. However, necroptotic stimuli activate HSCs instead of inducing cell death. MLKL inhibitors attenuated fibrogenic changes in HSCs during necroptosis. Unlike HT-29 and U937 cells, MLKL phosphorylation and oligomerization were not observed during necroptosis in HSCs. RNA sequencing showed that NF-κB signaling-related genes were upregulated in HSCs following necroptotic stimulation. Necroptotic stimuli in HSCs increased the nuclear expression of NF-κB, which decreased after MLKL inhibitor treatment. Induction of necroptosis in HSCs led to autophagosome activation and formation, which were attenuated by MLKL inhibitor treatment.

CONCLUSION

HSCs avoid necroptosis due to the absence of MLKL phosphorylation and oligomerization and are activated through autophagosome and NF-κB pathways.

The evolving role of liver sinusoidal endothelial cells in liver health and disease

LSECs are a unique population of endothelial cells within the liver and are recognized as key regulators of liver homeostasis. LSECs also play a key role in liver disease, as dysregulation of their quiescent phenotype promotes pathological processes within the liver including inflammation, microvascular thrombosis, fibrosis, and portal hypertension. Recent technical advances in single-cell analysis have characterized distinct subpopulations of the LSECs themselves with a high resolution and defined their gene expression profile and phenotype, broadening our understanding of their mechanistic role in liver biology. This article will review 4 broad advances in our understanding of LSEC biology in general: (1) LSEC heterogeneity, (2) LSEC aging and senescence, (3) LSEC role in liver regeneration, and (4) LSEC role in liver inflammation and will then review the role of LSECs in various liver pathologies including fibrosis, DILI, alcohol-associated liver disease, NASH, viral hepatitis, liver transplant rejection, and ischemia reperfusion injury. The review will conclude with a discussion of gaps in knowledge and areas for future research.

Endotheliopathy in the metabolic syndrome: Mechanisms and clinical implications

The increasing prevalence of the metabolic syndrome (MetS) is a threat to global public health due to its lethal complications. Nonalcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the MetS characterized by hepatic steatosis, which is potentially progressive to the inflammatory and fibrotic nonalcoholic steatohepatitis (NASH). The adipose tissue (AT) is also a major metabolic organ responsible for the regulation of whole-body energy homeostasis, and thereby highly involved in the pathogenesis of the MetS. Recent studies suggest that endothelial cells (ECs) in the liver and AT are not just inert conduits but also crucial mediators in various biological processes via the interaction with other cell types in the microenvironment both under physiological and pathological conditions. Herein, we highlight the current knowledge of the role of the specialized liver sinusoidal endothelial cells (LSECs) in NAFLD pathophysiology. Next, we discuss the processes through which AT EC dysfunction leads to MetS progression, with a focus on inflammation and angiogenesis in the AT as well as on endothelial-to-mesenchymal transition of AT-ECs. In addition, we touch upon the function of ECs residing in other metabolic organs including the pancreatic islet and the gut, the dysregulation of which may also contribute to the MetS. Finally, we highlight potential EC-based therapeutic targets for human MetS, and NASH based on recent achievements in basic and clinical research and discuss how to approach unsolved problems in the field.

Analysis of the Role of Stellate Cell VCAM-1 in NASH Models in Mice

Non-alcoholic fatty liver disease (NAFLD) can progress to non-alcoholic steatohepatitis (NASH), characterized by inflammation and fibrosis. Fibrosis is mediated by hepatic stellate cells (HSC) and their differentiation into activated myofibroblasts; the latter process is also promoted by inflammation. Here we studied the role of the pro-inflammatory adhesion molecule vascular cell adhesion molecule-1 (VCAM-1) in HSCs in NASH. VCAM-1 expression was upregulated in the liver upon NASH induction, and VCAM-1 was found to be present on activated HSCs. We therefore utilized HSC-specific VCAM-1-deficient and appropriate control mice to explore the role of VCAM-1 on HSCs in NASH. However, HSC-specific VCAM-1-deficient mice, as compared to control mice, did not show a difference with regards to steatosis, inflammation and fibrosis in two different models of NASH. Hence, VCAM-1 on HSCs is dispensable for NASH development and progression in mice.

Metabolic dysfunction associated fatty liver disease identifies subjects with cardiovascular risk better than non-alcoholic fatty liver disease

BACKGROUND AND AIMS

Cardiovascular disease (CVD) is the main cause of mortality in subjects with non-alcoholic fatty liver disease (NAFLD). We investigated the association between CVD risk and metabolic dysfunction-associated fatty liver disease (MAFLD) or NAFLD and the influence of significant liver fibrosis on the CVD risk.

METHODS

Subjects who underwent a comprehensive medical check-up were recruited (2014-2019). Significant liver fibrosis was defined using NAFLD fibrosis score, fibrosis-4 index, aspartate aminotransferase to platelet ratio index, or FibroScan-aspartate aminotransferase score. High probability of atherosclerotic CVD (ASCVD) was defined as ASCVD risk score > 10%.

RESULTS

Of the study population (n = 78 762), 27 047 (34.3%) and 24 036 (30.5%) subjects had MAFLD and NAFLD respectively. A total of 1084 (4.0%) or 921 (3.8%) subjects had previous CVD history in MAFLD or NAFLD subgroup respectively. The previous CVD history and high probability of ASCVD were significantly higher in MAFLD or NAFLD subgroup with significant liver fibrosis than in the other groups (all p < .001). In multivariable analysis, MAFLD was independently associated with previous CVD history after adjusting for confounders (adjusted odds ratio [aOR] = 1.10, p = .038), whereas NAFLD was not (all p > .05). MAFLD (aOR = 1.40) or NAFLD (aOR = 1.22) was independently associated with high probability of ASCVD after full adjustment respectively (all p < .001). Significant liver fibrosis was independently associated with previous CVD history and high probability of ASCVD after adjustment in MAFLD or NAFLD subgroup respectively (all p < .05).

CONCLUSION

MAFLD might better identify subjects with CVD risk than NAFLD. Fibrosis assessment might be helpful for detailed prognostication in subjects with MAFLD.

Liver sinusoidal endothelial cell expressed vascular cell adhesion molecule 1 promotes liver fibrosis

Background

During liver injury, liver sinusoidal endothelial cells (LSECs) dysfunction and capillarization promote liver fibrosis. We have previously reported that the LSEC vascular cell adhesion molecule 1 (VCAM1) plays a key role in liver inflammation in nonalcoholic steatohepatitis (NASH) and we now aim to uncover its role in LSEC capillarization and liver fibrosis.

Methods

Wild-type C57BL/6J mice were fed either chow or high fat, fructose and cholesterol diet to induce NASH and treated with either anti-VCAM1 neutralizing antibody or control isotype antibody. Inducible endothelial cell-specific Vcam1 deleted mice (Vcam1^Δend ) and control mice (Vcam1^fl/fl ) were fed choline-deficient high-fat diet (CD-HFD) to induce NASH or injected with carbon tetrachloride to induce liver fibrosis. LSECs isolated from Vcam1^fl/fl or Vcam1^Δend and hepatic stellate cells (HSCs) isolated from wild-type mice were cocultured in a 3-D system or a μ-Slide 2 well co-culture system.

Results

Immunostaining for Lyve1 (marker of differentiated LSECs) was reduced in Vcam1^fl/fl mice and restored in Vcam1^Δend mice in both NASH and liver fibrosis models. Co-immunostaining showed increased α-smooth muscle actin in the livers of Vcam1^fl/fl mice in areas lacking Lyve1. Furthermore, scanning electron microscopy showed reduced LSEC fenestrae in the Vcam1^fl/fl mice but not Vcam1^Δend mice in both injury models, suggesting that VCAM1 promotes LSEC capillarization during liver injury. HSCs profibrogenic markers were reduced when cocultured with LSECs from CD-HFD fed Vcam1^Δend mice compared to Vcam1^fl/fl mice. Furthermore, recombinant VCAM1 activated the Yes-associated protein 1 pathway and induced a fibrogenic phenotype in HSCs in vitro, supporting the profibrogenic role of LSEC VCAM1.

Conclusion

VCAM1 is not just a scaffold for leukocyte adhesion during liver injury, but also a modulator of LSEC capillarization and liver fibrosis.

Combined Therapy with a CCR2/CCR5 Antagonist and FGF21 Analogue Synergizes in Ameliorating Steatohepatitis and Fibrosis

(1) Background: With new potential drug targets emerging, combination therapies appear attractive to treat non-alcoholic steatohepatitis (NASH) and fibrosis. Chemokine receptor CCR2/5 antagonists can improve fibrosis by reducing monocyte infiltration and altering hepatic macrophage subsets. Fibroblast growth factor 21 (FGF21) may improve NASH by modulating lipid and glucose metabolism. We compared effects of single drug to combination treatment as therapeutic strategies against NASH. (2) Methods: We analyzed serum samples and liver biopsies from 85 nonalcoholic fatty liver disease (NAFLD) patients. A CCR2/5 inhibitor (BMS-687681-02-020) and a pegylated FGF21 agonist (BMS-986171) were tested in male C57BL/6J mice subjected to dietary models of NASH and fibrosis (choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) up to 12 weeks; short- (2w) or long-term (6w) treatment). (3) Results: In NAFLD patients, chemokine CCL2 and FGF21 serum levels correlated with inflammatory serum markers, only CCL2 was significantly associated with advanced liver fibrosis. In rodent NASH, CCR2/5 inhibition significantly reduced circulating Ly6C+ monocytes and hepatic monocyte-derived macrophages, alongside reduced hepatic inflammation and fibrosis. FGF21 agonism decreased body weight, liver triglycerides and histological NASH activity. Combination treatment reflected aspects of both compounds upon short- and long-term application, thereby amplifying beneficial effects on all aspects of steatohepatitis and fibrosis. (4) Conclusions: CCR2/5 inhibition blocks hepatic infiltration of inflammatory monocytes, FGF21 agonism improves obesity-related metabolic disorders. Combined therapy ameliorates steatohepatitis and fibrosis more potently than single drug treatment in rodent NASH, corroborating the therapeutic potential of combining these two approaches in NASH patients.

Reprogramming of Hepatic Metabolism and Microenvironment in Nonalcoholic Steatohepatitis

Nonalcoholic fatty liver disease (NAFLD), a spectrum of metabolic liver disease associated with obesity, ranges from relatively benign hepatic steatosis to nonalcoholic steatohepatitis (NASH). The latter is characterized by persistent liver injury, inflammation, and liver fibrosis, which collectively increase the risk for end-stage liver diseases such as cirrhosis and hepatocellular carcinoma. Recent work has shed new light on the pathophysiology of NAFLD/NASH, particularly the role of genetic, epigenetic, and dietary factors and metabolic dysfunctions in other tissues in driving excess hepatic fat accumulation and liver injury. In parallel, single-cell RNA sequencing studies have revealed unprecedented details of the molecular nature of liver cell heterogeneity, intrahepatic cross talk, and disease-associated reprogramming of the liver immune and stromal vascular microenvironment. This review covers the recent advances in these areas, the emerging concepts of NASH pathogenesis, and potential new therapeutic opportunities. Expected final online publication date for the Annual Review of Nutrition, Volume 42 is August 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Serum Proteomics Uncovers Biomarkers of Clinical Portal Hypertension in Children With Biliary Atresia

Children with biliary atresia (BA) often develop portal hypertension (PHT) and its complications, which are associated with high morbidity and mortality. The goal of this study was to identify serum biomarkers of PHT by using large-scale proteomics. We applied the slow off-rate modified aptamer scan (SOMAscan) to measure 1,305 proteins in serum samples of children with BA with and without clinical evidence of PHT in validation and discovery cohorts enrolled in the Biliary Atresia Study of Infants and Children. Serum proteomics data was analyzed using logistic regression to identify protein(s) with an area under the receiver operating characteristic curve (AUROC) ≥ 0.90. Immunostaining was used to characterize the cellular localization of the new biomarker proteins in liver tissues. We identified nine proteins in the discovery cohort (n = 40 subjects) and five proteins in the validation cohort (n = 80 subjects) that individually or in combination predicted clinical PHT with AUROCs ≥ 0.90. Merging the two cohorts, we found that semaphorin 6B (SEMA6B) alone and three other protein combinations (SEMA6B+secreted frizzle protein 3 [SFRP3], SEMA6B+COMM domain containing 7 [COMMD7], and vascular cell adhesion molecule 1 [VCAM1]+BMX nonreceptor tyrosine kinase [BMX]) had AUROCs ≥ 0.90 in both cohorts, with high positive- and negative-predictive values. Immunostaining of the new protein biomarkers showed increased expression in hepatic endothelial cells, cholangiocytes, and immune cells within portal triads in BA livers with clinical PHT compared to healthy livers. Conclusion: Large-scale proteomics identified SEMA6B, SFRP3, COMMD7, BMX, and VCAM1 as biomarkers highly associated with clinical PHT in BA. The expression of the biomarkers in hepatic epithelial, endothelial, and immune cells support their potential role in the pathophysiology of PHT.

Coagulation and Endothelial Dysfunction Associated with NAFLD: Current Status and Therapeutic Implications

Non-alcoholic fatty liver disease (NAFLD) is closely related to insulin resistance, type 2 diabetes mellitus and obesity. It is considered a multisystem disease and there is a strong association with cardiovascular disease and arterial hypertension, which interfere with changes in the coagulation system. Coagulation disorders are common in patients with hepatic impairment and are dependent on the degree of liver damage. Through a review of the literature, we consider and discuss possible disorders in the coagulation cascade and fibrinolysis, endothelial dysfunction and platelet abnormalities in patients with NAFLD.

Current Options and Future Directions for NAFLD and NASH Treatment

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, with a broad spectrum ranging from simple steatosis to advanced stage of nonalcoholic steatohepatitis (NASH). Although there are many undergoing clinical trials for NAFLD treatment, there is no currently approved treatment. NAFLD accounts as a major causing factor for the development of hepatocellular carcinoma (HCC), and its incidence rises accompanying the prevalence of obesity and diabetes. Reprogramming of antidiabetic and anti-obesity medicine is a major treatment option for NAFLD and NASH. Liver inflammation and cellular death, with or without fibrosis account for the progression of NAFLD to NASH. Therefore, molecules and signaling pathways involved in hepatic inflammation, fibrosis, and cell death are critically important targets for the therapy of NAFLD and NASH. In addition, the avoidance of aberrant infiltration of inflammatory cytokines by treating with CCR antagonists also provides a therapeutic option. Currently, there is an increasing number of pre-clinical and clinical trials undergoing to evaluate the effects of antidiabetic and anti-obesity drugs, antibiotics, pan-caspase inhibitors, CCR2/5 antagonists, and others on NAFLD, NASH, and liver fibrosis. Non-invasive serum diagnostic markers are developed for fulfilling the need of diagnostic testing in a large amount of NAFLD cases. Overall, a better understanding of the underlying mechanism of the pathogenesis of NAFLD is helpful to choose an optimized treatment.

Sinusoidal endotheliopathy in nonalcoholic steatohepatitis: therapeutic implications

Liver sinusoidal endothelial cells (LSECs) are distinct subtypes of endothelial cells lining a low flow vascular bed at the interface of the liver parenchyma and the circulating immune cells and soluble factors. Emerging literature implicates LSEC in the pathogenesis and progression of nonalcoholic fatty liver disease (NAFLD). During the evolution of NAFLD, LSEC dysfunction ensues. LSECs undergo morphological and functional transformation known as "capillarization," as well as a pathogenic increase in surface adhesion molecules expression, referred to in this review as "endotheliopathy." LSECs govern the composition of hepatic immune cell populations in nonalcoholic steatohepatis (NASH) by mediating leukocyte subset adhesion through specific combinations of activated adhesion molecules and secreted chemokines. Moreover, extracellular vesicles released by hepatocyte under lipotoxic stress in NASH act as a catalyst for the inflammatory response and promote immune cell chemotaxis and adhesion. In the current review, we highlight leukocyte adhesion to LSEC as an initiating event in the sterile inflammatory response in NASH. We discuss preclinical studies targeting immune cells adhesion in NASH mouse models and potential therapeutic anti-inflammatory strategies for human NASH.

Endothelial dysfunction markers predict short-term mortality in patients with severe alcoholic hepatitis

OBJECTIVES

Alcoholic hepatitis (AH) is a severe condition characterized by a marked inflammatory response and high short-term mortality. Endothelial dysfunction (ED) is an early event in vascular and inflammatory disorders. The aim of this study is to evaluate ED in AH patients.

METHODS

Prognostic value of ED biomarkers was evaluated in patients with severe AH (n = 67), compensated alcoholic cirrhosis (n = 15), heavy drinkers without liver disease (n = 15) and controls (n = 9), and in a validation cohort of 50 patients with AH. Gene expression of ED markers was analyzed in liver tissue.

RESULTS

Plasma levels of ED markers such as vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), E-selectin and von Willebrand factor (vWF) increased along alcohol-related liver disease (ALD) progression. Intergroup analysis showed a significant increase of these markers in AH patients. In addition, VCAM-1 showed a positive correlation with Maddrey, MELD and ABIC scores and inflammation parameters (i.e. C-reactive protein and LPS levels). Importantly, levels of VCAM-1 were higher in patients with increased mortality and were independently associated with short-term survival (90-day) when adjusted by ABIC score. These results were confirmed in an independent cohort of AH patients. In addition, severe AH patients showed altered hepatic expression of ED markers.

CONCLUSIONS

In this study we show that advanced ALD and particularly severe AH is associated with an increase of ED biomarkers, which correlate with patient outcomes. These results suggest that ED may be a pathogenic event in AH and highlight endothelial factors as potential biomarkers in AH.

Gut-Liver Axis in Nonalcoholic Fatty Liver Disease: the Impact of the Metagenome, End Products, and the Epithelial and Vascular Barriers

Nonalcoholic fatty liver disease (NAFLD) is a systemic, dynamic, heterogeneous, and multiaxis entity, the pathogenesis of which is still uncertain. The gut-liver axis is regulated and stabilized by a complex network encompassing a metabolic, immune, and neuroendocrine cross-talk between the gut, the microbiota, and the liver. Changes in the gut-liver axis affect the metabolism of lipids and carbohydrates in the hepatocytes, and they impact the balance of inflammatory mediators and cause metabolic deregulation, promoting NAFLD and its progression to nonalcoholic steatohepatitis. Moreover, the microbiota and its metabolites can play direct and indirect roles in gut barrier function and fibrosis development. In this review, we will highlight findings from the recent literature focusing on the gut-liver axis and its relation to NAFLD. Finally, we will discuss the impact of technical issues, design bias, and other limitations on current knowledge of the gut microbiota in the context of NAFLD.

SOMAscan Proteomics Identifies Serum Biomarkers Associated With Liver Fibrosis in Patients With NASH

Nonalcoholic steatohepatitis (NASH) is a major cause of liver-related morbidity and mortality worldwide. Liver fibrosis stage, a key component of NASH, has been linked to the risk of mortality and liver-related clinical outcomes. Currently there are no validated noninvasive diagnostics that can differentiate between fibrosis stages in patients with NASH; many existing tests do not reflect underlying disease pathophysiology. Noninvasive biomarkers are needed to identify patients at high-risk of NASH with advanced fibrosis. This was a retrospective study of patients with histologically proven NASH with fibrosis stages 0-4. The SOMAscan proteomics platform was used to quantify 1,305 serum proteins in a discovery cohort (n = 113). In patients with advanced (stages 3-4) versus early fibrosis (stages 0-2), 97 proteins with diverse biological functions were differentially expressed. Next, fibrosis-stage classification models were explored using a machine learning-based approach to prioritize the biomarkers for further evaluation. A four-protein model differentiated patients with stage 0-1 versus stage 2-4 fibrosis (area under the receiver operating characteristic curve [AUROC] = 0.74), while a 12-protein classifier differentiated advanced versus early fibrosis (AUROC = 0.83). Subsequently, the model's performance was validated in two independent cohorts (n = 71 and n = 32) with similar results (AUROC = 0.74-0.78). Our advanced fibrosis model performed similarly to or better than Fibrosis-4 index, aspartate aminotransferase-to-platelet ratio index, and nonalcoholic fatty liver disease (NAFLD) fibrosis score-based models for all three cohorts. Conclusion: A SOMAscan proteomics-based exploratory classifier for advanced fibrosis, consisting of biomarkers that reflect the complexity of NASH pathophysiology, demonstrated similar performance in independent validation cohorts and performed similarly or better than Fibrosis-4 index, aspartate aminotransferase-to-platelet ratio index, and NAFLD fibrosis score. Further studies are warranted to evaluate the clinical utility of these biomarker panels in patients with NAFLD.

Role of Angiogenesis in the Pathogenesis of NAFLD

Non-alcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver disease, exposing to the risk of liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Angio-genesis is a complex process leading to the development of new vessels from pre-existing vessels. Angiogenesis is triggered by hypoxia and inflammation and is driven by the action of proangiogenic cytokines, mainly vascular endothelial growth factor (VEGF). In this review, we focus on liver angiogenesis associated with NAFLD and analyze the evidence of liver angiogenesis in animal models of NAFLD and in NAFLD patients. We also report the data explaining the role of angiogenesis in the progression of NAFLD and discuss the potential of targeting angiogenesis, notably VEGF, to treat NAFLD.

Lipid-induced endothelial vascular cell adhesion molecule 1 promotes nonalcoholic steatohepatitis pathogenesis

Monocyte homing to the liver and adhesion to the liver sinusoidal endothelial cells (LSECs) are key elements in nonalcoholic steatohepatitis (NASH) pathogenesis. We reported previously that VCAM-1 mediates monocyte adhesion to LSECs. However, the pathogenic role of VCAM-1 in NASH is unclear. Herein, we report that VCAM-1 was a top upregulated adhesion molecule in the NASH mouse liver transcriptome. Open chromatin landscape profiling combined with genome-wide transcriptome analysis showed robust transcriptional upregulation of LSEC VCAM-1 in murine NASH. Moreover, LSEC VCAM-1 expression was significantly increased in human NASH. LSEC VCAM-1 expression was upregulated by palmitate treatment in vitro and reduced with inhibition of the mitogen-activated protein 3 kinase (MAP3K) mixed lineage kinase 3 (MLK3). Likewise, LSEC VCAM-1 expression was reduced in the Mlk3-/- mice with diet-induced NASH. Furthermore, VCAM-1 neutralizing Ab or pharmacological inhibition attenuated diet-induced NASH in mice, mainly via reducing the proinflammatory monocyte hepatic population as examined by mass cytometry by time of flight (CyTOF). Moreover, endothelium-specific Vcam1 knockout mice were also protected against NASH. In summary, lipotoxic stress enhances the expression of LSEC VCAM-1, in part, through MLK3 signaling. Inhibition of VCAM-1 was salutary in murine NASH and might serve as a potential therapeutic strategy for human NASH.

A 3D Human Liver Model of Nonalcoholic Steatohepatitis

Background and Aims: To better understand nonalcoholic steatohepatitis (NASH) disease progression and to evaluate drug targets and compound activity, we undertook the development of an in vitro 3D model to mimic liver architecture and the NASH environment. Methods: We have developed an in vitro preclinical 3D NASH model by coculturing primary human hepatocytes, human stellate cells, liver endothelial cells and Kupffer cells embedded in a hydrogel of rat collagen on a 96-well plate. A NASH-like environment was induced by addition of medium containing free fatty acids and tumor necrosis factor-α. This model was then characterized by biochemical, imaging and transcriptomics analyses. Results: We succeeded in defining suitable culture conditions to maintain the 3D coculture for up to 10 days in vitro, with the lowest level of steatosis and reproducible low level of inflammation and fibrosis. NASH disease was induced with a custom medium mimicking NASH features. The cell model exhibited the key NASH disease phenotypes of hepatocyte injury, steatosis, inflammation, and fibrosis. Hepatocyte injury was highlighted by a decrease of CYP3A4 expression and activity, without loss of viability up to day 10. Moreover, the model was able to stimulate a stable inflammatory and early fibrotic environment, with expression and secretion of several cytokines. A global gene expression analysis confirmed the NASH induction. Conclusions: This is a new in vitro model of NASH disease consisting of four human primary cell-types that exhibits most features of the disease. The 10-day cell viability and cost effectiveness of the model make it suitable for medium throughput drug screening and provide attractive avenues to better understand disease physiology and to identify and characterize new drug targets.

Emerging Roles of Liver Sinusoidal Endothelial Cells in Nonalcoholic Steatohepatitis

Simple Summary

Nonalcoholic fatty liver disease (NAFLD) is a hepatic manifestation of the metabolic syndrome. With the prevalence of obesity and type 2 diabetes, NAFLD is becoming the most common liver disorder worldwide. More than 10% of NAFLD patients progress to an inflammatory and fibrotic form called nonalcoholic steatohepatitis (NASH), which can lead to end-stage liver disease. Liver sinusoidal endothelial cells (LSEC) are highly specialized cells located at the interface between the flowing blood in the liver and the other liver cells. The current review highlights the recent knowledge of the role of LSEC in the development of NASH, and how LSEC change their structure and function during NAFLD progression. Moreover, the review discusses the pathogenic role of nanometer-sized particles called extracellular vesicles that mediate intercellular communication in the NASH liver. The current manuscript has a special emphasis on the role of adhesion molecules expressed on the LSEC surface in the recruitment of circulating leukocytes to the liver, a critical step in liver inflammation in NASH. Furthermore, the review shed some lights on LSEC-targeted potential therapeutic strategies in NASH.

Abstract

Nonalcoholic steatohepatitis (NASH) has become a growing public health problem worldwide, yet its pathophysiology remains unclear. Liver sinusoidal endothelial cells (LSEC) have unique morphology and function, and play a critical role in liver homeostasis. Emerging literature implicates LSEC in many pathological processes in the liver, including metabolic dysregulation, inflammation, angiogenesis, and carcinogenesis. In this review, we highlight the current knowledge of the role of LSEC in each of the progressive phases of NASH pathophysiology (steatosis, inflammation, fibrosis, and the development of hepatocellular carcinoma). We discuss processes that have important roles in NASH progression including the detrimental transformation of LSEC called “capillarization”, production of inflammatory and profibrogenic mediators by LSEC as well as LSEC-mediated angiogenesis. The current review has a special emphasis on LSEC adhesion molecules, and their key role in the inflammatory response in NASH. Moreover, we discuss the pathogenic role of extracellular vesicles and their bioactive cargos in liver intercellular communication, inflammation, and fibrosis. Finally, we highlight LSEC-adhesion molecules and derived bioactive product as potential therapeutic targets for human NASH.

L-Selectin/CD62L is a Key Driver of Non-Alcoholic Steatohepatitis in Mice and Men

CD62L (L-Selectin) dependent lymphocyte infiltration is known to induce inflammatory bowel disease (IBD), while its function in the liver, especially in non-alcoholic steatohepatitis (NASH), remains unclear. We here investigated the functional role of CD62L in NASH in humans as well as in two mouse models of steatohepatitis. Hepatic expression of a soluble form of CD62L (sCD62L) was measured in patients with steatosis and NASH. Furthermore, CD62L^−/− mice were fed with a methionine and choline deficient (MCD) diet for 4 weeks or with a high fat diet (HFD) for 24 weeks. Patients with NASH displayed increased serum levels of sCD62L. Hepatic CD62L expression was higher in patients with steatosis and increased dramatically in NASH patients. Interestingly, compared to wild type (WT) mice, MCD and HFD-treated CD62L^−/− mice were protected from diet-induced steatohepatitis. This was reflected by less fat accumulation in hepatocytes and a dampened manifestation of the metabolic syndrome with an improved insulin resistance and decreased cholesterol and triglyceride levels. Consistent with ameliorated disease, CD62L^−/− animals exhibited an enhanced hepatic infiltration of Treg cells and a strong activation of an anti-oxidative stress response. Those changes finally resulted in less fibrosis in CD62L^−/− mice. Additionally, this effect could be reproduced in a therapeutic setting by administrating an anti-CD62L blocking antibody. CD62L expression in humans and mice correlates with disease activity of steatohepatitis. CD62L knockout and anti-CD62L-treated mice are protected from diet-induced steatohepatitis suggesting that CD62L is a promising target for therapeutic interventions in NASH.

Urinary fatty acid and retinol binding protein-4 predict CKD progression in severe NAFLD patients with hypertension: 4-year study with clinical and experimental approaches

Detection of the chronic kidney disease (CKD) progression can begin early intervention to improve the prognosis of severe non-alcoholic fatty liver disease (NAFLD). This bi-directional cross-sectional study evaluates the roles of fatty acid-binding protein (FABP) and retinol binding protein (RBP4), which are produced from inflamed liver, adipose tissue and immune cells, for the prediction of CKD progression in severe NAFLD. Ninety severe NAFLD patients with hypertension and proteinuria (NAFLDHTN) were enrolled and divided into CKD (n = 39) and non-CKD groups (n = 51). Among 39 NAFLDHTN patients, 18 cases were categorized as CKD progression group. In comparison with CKD stable group (n = 21), the positive correlation between fold change values of hepatic fibrotic score (KPa), urinary FABP4 or urinary RBP4 versus severity of albuminuria were noted among CKD progression group. On multivariate analysis, high body mass index (BMI, >25 kg/m), high hepatic fibrosis score (>9.5 KPa), high urinary level of vascular cell adhesion molecule-1 (VCAM-1, >2239 μg/g cr), high urinary level of FABP4 (>115 ng/g cr) and high urinary level of RBP4 (>33.5 mg/g cr) are 5 independent predictors for progressive CKD during 24 months of follow-up. Synergetic effect was noted among these 5 risk factors for the prediction of CKD progression in NAFLDHTN patients. The in vitro experiments revealed that both FABP4 and RBP4 directly enhanced albumin-induced ER stress and apoptosis of human renal tubular epithelial cell line HK-2 cells and human podocytes cell lines. Through clinical and experimental approaches, this study revealed new 5 synergetic predictors including high BMI, hepatic fibrosis score, urinary level of VCAM-1, urinary level of FABP4 and RBP4, for the CKD progression in severe NAFLD patients with hypertension and proteinuria.

Macrophage Function in the Pathogenesis of Non-alcoholic Fatty Liver Disease: The Mac Attack

Obesity is a prevalent predisposing factor to non-alcoholic fatty liver disease (NAFLD), the most common chronic liver disease in the developed world. NAFLD spectrum of disease involves progression from steatosis (NAFL), to steatohepatitis (NASH), cirrhosis and hepatocellular carcinoma (HCC). Despite clinical and public health significance, current FDA approved therapies for NAFLD are lacking in part due to insufficient understanding of pathogenic mechanisms driving disease progression. The etiology of NAFLD is multifactorial. The induction of both systemic and tissue inflammation consequential of skewed immune cell metabolic state, polarization, tissue recruitment, and activation are central to NAFLD progression. Here, we review the current understanding of the above stated cellular and molecular processes that govern macrophage contribution to NAFLD pathogenesis and how adipose tissue and liver crosstalk modulates macrophage function. Notably, the manipulation of such events may lead to the development of new therapies for NAFLD.

The Many Roles of Cell Adhesion Molecules in Hepatic Fibrosis

Fibrogenesis is a progressive scarring event resulting from disrupted regular wound healing due to repeated tissue injury and can end in organ failure, like in liver cirrhosis. The protagonists in this process, either liver-resident cells or patrolling leukocytes attracted to the site of tissue damage, interact with each other by soluble factors but also by direct cell–cell contact mediated by cell adhesion molecules. Since cell adhesion molecules also support binding to the extracellular matrix, they represent excellent biosensors, which allow cells to modulate their behavior based on changes in the surrounding microenvironment. In this review, we focus on selectins, cadherins, integrins and members of the immunoglobulin superfamily of adhesion molecules as well as some non-classical cell adhesion molecules in the context of hepatic fibrosis. We describe their liver-specific contributions to leukocyte recruitment, cell differentiation and survival, matrix remodeling or angiogenesis and touch on their suitability as targets in antifibrotic therapies.

Assay validation and clinical performance of chronic inflammatory and chemokine biomarkers of NASH fibrosis

Nonalcoholic steatohepatitis (NASH) is a chronic liver disease that can lead to cirrhosis, liver transplant, and even hepatocellular carcinoma. While liver biopsy remains the reference standard for disease diagnosis, analytical and clinical development of non-invasive soluble biomarkers of NASH are of great importance to advance the field. To this end, we performed analytical and clinical validation on a series of pro-inflammatory cytokines and chemokines implicated hepatic inflammation; IL-6, CRP, TNFα, MCP-1, MIP-1β, eotaxin, VCAM-1. Biomarker assays were validated for accuracy and precision. Clinical performance was evaluated in a random sample of 52 patients with biopsy-proven NAFLD/NASH. Patients were categorized into three groups according to their fibrosis stage; advanced (F3-F4), mild (F1-2) and no (F0) fibrosis. Serum IL-6 was increased in patients with advanced fibrosis (2.71 pg/mL; 1.26 pg/mL; 1.39 pg/mL p<0.01) compared to patients with mild or no fibrosis respectively. While, there was no significant difference noted in CRP, TNFα, MCP-1, MIP-1β, eotaxin among the three groups, VCAM-1 levels were increased by 55% (p<0.01) and 40% (p<0.05) in the advanced cohort compared to the mild and no fibrosis groups respectively. VCAM-1 also displayed good clinical performance as a biomarker of advanced fibrosis with an area under the receiver operating curve of 0.87. The VCAM-1 assay demonstrated robust accuracy and precision, and VCAM-1 outperformed IL-6, CRP, TNFα, and the chemokines MCP-1, MIP-1β, and eotaxin as a biomarker of advanced fibrosis in NASH. Addition of biomarkers such as IL-6 and VCAM-1 to panels may yield increased sensitivity and specificity for staging of NASH.

Angiotensin II Type 1 Receptor rs5186 Gene Variant Predicts Incident NAFLD and Associated Hypertension: Role of Dietary Fat-Induced Pro-Inflammatory Cell Activation

OBJECTIVES

Hypertension has been linked to the presence and severity of nonalcoholic fatty liver disease (NAFLD) through unclear mechanisms. The gain-of-function rs5186 A1166C variant in angtiotensin receptor type 1 (AGTR1) gene has been linked to hypertension, cardiovascular disease and metabolic syndrome. We assessed the impact of AGTR1 A1166C variant on NAFLD incidence and severity and on glucose and lipid metabolism and explored the underlying mechanisms.

METHODS

We followed up 314 healthy nonobese, nondiabetic, nonhypertensive, insulin-sensitive participants in a population-based study, characterized for AGTR1 rs5186 A1166C variant, adipokine profile, inflammatory and endothelial dysfunction markers. An independent cohort of 78 biopsy-proven nondiabetic NAFLD patients and controls underwent an oral glucose tolerance test with Minimal Model analysis of glucose homeostasis, and an oral fat tolerance test with measurement of plasma lipoproteins, adipokines, MCP-1, calprotectin, and nuclear factor-κB activation in circulating mononuclear cells.

RESULTS

AGTR1 A1166C polymorphism predicted 9.8-year incident NAFLD (odds ratio: 1.67, 95% CI: 1.26-2.21) and hypertension (odds ratio: 1.49, 95% CI: 1.12-2.63) and 9-year increase in cardiovascular disease risk and endothelial dysfunction markers. In the cross-sectional cohort, AGTR1 C allele carriers had higher insulin resistance. Despite comparable fasting lipid profiles, AGTR1 C allele carriers showed postprandial triglyceride-rich and cholesterol-rich VLDL lipoprotein accumulation, higher resistin, MCP-1 and calprotectin responses and nuclear factor-κB activation in mononuclear cells, and a blunted postprandial adiponectin response to fat, which predicted liver histology, hepatocyte apoptosis activation, insulin resistance, and endothelial dysfunction.

DISCUSSION

AGTR1 A1166C variant affects liver disease, insulin resistance, and endothelial dysfunction in NAFLD, at least in part by modulating adipokine, chemokine, and pro-inflammatory cell activation in response to fat ingestion.

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.

Macrophages in obesity and non-alcoholic fatty liver disease: Crosstalk with metabolism

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide, and a major cause of liver cirrhosis and hepatocellular carcinoma. NAFLD is intimately linked with other metabolic disorders characterized by insulin resistance. Metabolic diseases are driven by chronic inflammatory processes, in which macrophages perform essential roles. The polarization status of macrophages is itself influenced by metabolic stimuli such as fatty acids, which in turn affect the progression of metabolic dysfunction at multiple disease stages and in various tissues. For instance, adipose tissue macrophages respond to obesity, adipocyte stress and dietary factors by a specific metabolic and inflammatory programme that stimulates disease progression locally and in the liver. Kupffer cells and monocyte-derived macrophages represent ontologically distinct hepatic macrophage populations that perform a range of metabolic functions. These macrophages integrate signals from the gut-liver axis (related to dysbiosis, reduced intestinal barrier integrity, endotoxemia), from overnutrition, from systemic low-grade inflammation and from the local environment of a steatotic liver. This makes them central players in the progression of NAFLD to steatohepatitis (non-alcoholic steatohepatitis or NASH) and fibrosis. Moreover, the particular involvement of Kupffer cells in lipid metabolism, as well as the inflammatory activation of hepatic macrophages, may pathogenically link NAFLD/NASH and cardiovascular disease. In this review, we highlight the polarization, classification and function of macrophage subsets and their interaction with metabolic cues in the pathophysiology of obesity and NAFLD. Evidence from animal and clinical studies suggests that macrophage targeting may improve the course of NAFLD and related metabolic disorders.

Omentin-regulated proteins combine a pro-inflammatory phenotype with an anti-inflammatory counterregulation in human adipocytes: A proteomics analysis

AIMS

Experimental and epidemiological studies reported controversial data on the role of omentin in type 2 diabetes and cardiovascular diseases. This study aimed to characterise the impact of omentin on the secretome of human adipocytes to analyse the enrichment of these proteins in metabolic and cellular signalling pathways underlying its physiological function.

MATERIAL/METHODS

Differentiated primary human adipocytes were treated without or with 500 or 2000 ng/mL omentin for 24 hours. The secretome was analysed by liquid chromatography coupled tandem-mass spectrometry. Differences in protein secretion between untreated and omentin-treated adipocytes were compared using a paired t-test. Other potential upstream regulators and the overrepresentation in canonical pathways of omentin-stimulated proteins were analysed using Ingenuity Pathway Analysis.

RESULTS

The supernatant of adipocytes contained 3493 proteins, of which 140 were differentially secreted by both concentrations of omentin compared with untreated adipocytes. Among the most strongly increased proteins, tumour necrosis factor-inducible gene 6 protein (TNFAIP6) was increased by 140-fold in the supernatant. Omentin-regulated proteins were overrepresented in seven canonical pathways including eukaryotic initiation factor 2 signalling, complement system, and inhibition of matrix metalloproteases. We further identified 25 other potential upstream activators of omentin-regulated proteins, mainly pro-inflammatory cytokines and transcription regulators including NFκB.

CONCLUSIONS

In differentiated human adipocytes, the release of the anti-inflammatory TNFAIP6 might be part of a counterregulatory response to the pro-inflammatory action of omentin. Omentin-regulated proteins were overrepresented in pathways indicating cellular stress, a pro-inflammatory environment and a crosstalk with other organs. Other potential activators of omentin-regulated proteins point towards a central role of NFκB activation in the omentin-induced secretory process.

Accuracy of non-invasive scoring systems for diagnosing non-alcoholic steatohepatitis-related fibrosis: Multicenter validation study

AIM

Hepatic fibrosis is the most important factor for estimating the prognosis of patients with non-alcoholic fatty liver disease (NAFLD). A novel non-invasive scoring system, the FM-fibro index, showed high accuracy in a pilot study. The purpose of this study was to validate the efficacy of the FM-fibro index in a multicenter cohort.

METHODS

Among 18 institutions, we analyzed 400 Japanese patients with biopsy-proven NAFLD. We evaluated the accuracies of the FM-fibro index, CA-fibro index, and European Liver Fibrosis (ELF) panel by area under the receiver operator characteristics curves (AUROC). The FM-fibro index includes three formulas for type IV collagen 7S, hyaluronic acid, and vascular cell adhesion molecule-1.

RESULTS

Among 400 patients, 205 were women, and the median age was 56 years. The histological distribution of Matteoni types 1, 2, 3, and 4 was 11, 40, 15, and 334, and the distribution of hepatic fibrosis stages 0 to 4 was 67, 183, 55, 63, and 32, respectively. The AUROCs of the FM-fibro index, CA-fibro index, and ELF panel for non-alcoholic steatohepatitis (NASH)-related fibrosis were 0.7178/0.7095/0.7065, 0.7093, and 0.7245, respectively. The sensitivity and specificity of the FM-fibro index for predicting NASH-related fibrosis was 0.5359/0.5210/0.4641 and 0.8333/0.8182/0.8788, respectively. The accuracy of the FM-fibro index was not significantly different from that of the CA-fibro index or the ELF panel.

CONCLUSIONS

The FM-fibro index can predict NASH-related fibrosis with sufficient accuracy compared with previous scoring systems. Further analyses that verify the accuracy of the FM-fibro index to distinguish significant or advanced fibrosis in patients with NAFLD are awaited. (UMIN-CTR: UMIN000018158).

Endoglycosidase S Enables a Highly Simplified Clinical Chemistry Procedure for Direct Assessment of Serum IgG Undergalactosylation in Chronic Inflammatory Disease

Over the past 30 years, it has been firmly established that a wide spectrum of (autoimmune) diseases such as rheumatoid arthritis, Crohn's and lupus, but also other pathologies like alcoholic and non-alcoholic steatohepatitis (ASH and NASH) are driven by chronic inflammation and are hallmarked by a reduced level of serum IgG galactosylation. IgG (under)galactosylation is a promising biomarker to assess disease severity, and monitor and adjust therapy. However, this biomarker has not been implemented in routine clinical chemistry because of a complex analytical procedure that necessitates IgG purification, which is difficult to perform and validate at high throughput. We addressed this issue by using endo-β-N-acetylglucosaminidase from Streptococcus pyogenes (endoS) to specifically release Fc N-glycans in whole serum. The entire assay can be completed in a few hours and only entails adding endoS and labeling the glycans with APTS. Glycans are then readily analyzed through capillary electrophoresis. We demonstrate in two independent patient cohorts that IgG undergalactosylation levels obtained with this assay correlate very well with scores calculated from PNGaseF-released glycans of purified antibodies. Our new assay allows to directly and specifically measure the degree of IgG galactosylation in serum through a fast and completely liquid phase protocol, without the requirement for antibody purification. This should help advancing this biomarker toward clinical implementation.

Hypertension, diabetes, atherosclerosis and NASH: Cause or consequence?

Non-alcoholic fatty liver disease (NAFLD) has become one of the most common forms of chronic liver disease worldwide and its prevalence is expected to continue rising. NAFLD has traditionally been considered a consequence of metabolic syndrome (MetS). However, the link between NAFLD and MetS components, especially type 2 diabetes mellitus (T2DM), hypertension (HTN), and cardiovascular disease (CVD) is more complex than previously thought. Indeed, the adverse effects of NAFLD extend far beyond the liver, with a large body of clinical evidence now suggesting that NAFLD may precede and/or promote the development of T2DM, HTN and atherosclerosis/CVD. The risk of developing these cardiometabolic diseases parallels the underlying severity of NAFLD. Accumulating evidence suggests that the presence and severity of NAFLD is associated with an increased risk of incident T2DM and HTN. Moreover, long-term prospective studies indicate that the presence and severity of NAFLD independently predicts fatal and nonfatal CVD events. In this review, we critically discuss the rapidly expanding body of clinical evidence that supports the existence of a bi-directional relationship between NAFLD and various components of MetS, particularly T2DM and HTN, as well as the current knowledge regarding a strong association between NAFLD and CVD morbidity and mortality. Finally, we discuss the most updated putative biological mechanisms through which NAFLD may contribute to the development of HTN, T2DM and CVD.