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Treatments for nonalcoholic steatohepatitis (NASH) are urgently needed. Hepatic fat fraction and shear stiffness quantified by magnetic resonance imaging (MRI-HFF) and magnetic resonance elastography (MRE-SS), respectively, are biomarkers for hepatic steatosis and fibrosis.This study assessed the longitudinal effects of fibroblast growth factor 21 variant (polyethylene glycol [PEG]-FGF21v) on MRI-HFF and MRE-SS in a NASH mouse model.Preclinical.This study included a choline-deficient, amino acid-defined, high-fat diet (CDAHFD) model and 6-week-old, male C57BL/6J mice (N = 78).This study was performed using: 3T: gradient-echo two-point Dixon and spin-echo (SE) echo-planar imaging elastography (200 Hz) and 7T: SE two-point Dixon and SE elastography (200 Hz).MRI and MRE were performed before control diet (CD) or CDAHFD (BD), before PEG-FGF21v dosing (baseline), and after PEG-FGF21v treatment (WK4/8). Regions of interest for MRI-HFF and MRE-SS were delineated by J.L. and H.T. (5 years of experience each). Fibrosis and steatosis were measured histologically after picrosirius red and HE staining. Alkaline phosphatase, alanine transaminase, bile acids, and triglycerides (TGs) were measured.Two-tailed Dunnett's tests were used for statistical analysis; untreated CDAHFD or baseline was used for comparisons. Imaging and histology/biochemistry data were determined using Spearman correlations. Bayesian posterior distributions for MRE-SS at WK8, posterior means, and 95% credible intervals were presented.CDAHFD significantly increased baseline MRI-HFF (3T: 21.97% ± 0.29%; 7T: 40.12% ± 0.35%) and MRE-SS (3T: 1.25 ± 0.02; 7T: 1.78 ± 0.06 kPa) vs. CD (3T: 3.45% ± 0.7%; 7T: 12.06% ± 1.4% and 3T: 1.01 ± 0.02; 7T: 0.89 ± 0.06 kPa). At 7T, PEG-FGF21v significantly decreased MRI-HFF (WK4: 28.97% ± 1.22%; WK8: 20.93% ± 1.15%) and MRE-SS (WK4: 1.57 ± 0.04; WK8: 1.36 ± 0.05 kPa) vs. untreated (WK4: 36.36% ± 0.62%; WK8: 30.58% ± 0.81% and WK4: 2.03 ± 0.06; WK8: 2.01 ± 0.04 kPa); 3T trends were similar. WK8 SS posterior mean percent attenuation ratios (RMRI-HFF and MRE-SS showed PEG-FGF21v effects on hepatic steatosis and fibrosis across 3 and 7T, consistent with histological and biochemical data.1 TECHNICAL EFFICACY STAGE: 2.

The efficacy and safety of a fluid-filled intragastric balloon (IGB) for weight loss in patients with cirrhosis on the liver transplantation (LT) waiting list is unknown. We enrolled stable compensated patients with body mass index >35 kg/m2 and on the waiting list for IGB placement endoscopically for a maximum of 6 months. A total of 8 patients (7 men) aged mean ± SD, 56 ± 4.6 years with Model for End-Stage Liver Disease-sodium (MELD-Na) scores 14.1 ± 3.4 experienced weight reduction (146 ± 22.2 kg versus 127 ± 21.6 kg [P = 0.005] with IGB in place and 130 ± 24.6 kg [P = 0.014] at 6 months), with a total body weight loss of 12.2% ± 8.8% with IGBs in place and 10.9% ± 8.9% at 6 months. Body fat decreased from 48.6% ± 5.8% to 40.6% ± 6.4% (P = 0.001) and lean mass increased from 51.3% ± 6% to 59.4% ± 6.4% (P = 0.001). No change in MELD-Na scores occurred (P = 0.770). Early balloon retrieval was attributed to accommodative symptoms (n = 2) and liver decompensation (n = 1). Mallory Weiss tears (n = 3), but no portal hypertensive bleeding, occurred. Liver decompensation and/or hepatocellular carcinoma (HCC) developed in 3 patients. A total of 4 patients with LT ± sleeve gastrectomy maintained overall weight loss. Of 4 patients who did not receive transplants, 2 experienced weight regain. IGB results in short-term weight loss in patients with cirrhosis awaiting LT, with body fat loss without lean mass loss. Adverse effects were common. Decompensation and HCC did occur, with uncertainty of the relation to weight loss, and thus careful patient selection and close follow-up are required.

Immune activation is an important feature in the development and progression and nonalcoholic fatty liver disease (NAFLD). Macrophages are the most abundant immune cell type in the liver and are implicated in this process. However, intra-hepatic macrophages are a heterogeneous and dynamic population. They can be classified based on ontogeny into : yolk sac-derived tissue-resident macrophages, commonly referred to as Kupffer cells (KCs), and bone marrow (BM) monocyte-derived macrophages.

Nonalcoholic hepatitis (NASH) is the progressive inflammatory form of nonalcoholic fatty liver disease. Although the mechanisms of hepatic inflammation in NASH remain incompletely understood, emerging literature implicates the proinflammatory environment created by toxic lipid-induced hepatocyte injury, termed lipotoxicity. Interestingly, numerous NASH-promoting kinases in hepatocytes, immune cells, and adipocytes are activated by the lipotoxic insult associated with obesity. In the current review, we discuss recent advances in NASH-promoting kinases as disease mediators and therapeutic targets. The focus of the review is mainly on the mitogen-activated protein kinases including mixed lineage kinase 3, apoptosis signal-regulating kinase 1, c-Jun N-terminal kinase, and p38 MAPK; the endoplasmic reticulum (ER) stress kinases protein kinase RNA-like ER kinase and inositol-requiring protein-1α; as well as the Rho-associated protein kinase 1. We also discuss various pharmacological agents targeting these stress kinases in NASH that are under different phases of development.

BACKGROUND AND AIMS Interleukin-22 has beneficial effects on inflammation and impaired hepatic regeneration that characterize alcohol-associated hepatitis (AH). F-652 is a recombinant fusion protein of human interleukin-22 and immunoglobulin G2 fragment crystallizable. This study aims to assess the safety and efficacy signals of F-652 in patients with moderate and severe AH. APPROACH AND RESULTS A phase-2 dose-escalating study was carried out. F-652 (10 μg/kg, 30 μg/kg, or 45 μg/kg) administered on days 1 and 7 was tested in 3 patients each with moderate (Model for End-Stage Liver Disease [MELD] scores: 11-20) and severe AH (MELD scores: 21-28). Safety was defined by absence of serious adverse events and efficacy was assessed by Lille score, changes in MELD score, and serum bilirubin and aminotransferases at days 28 and 42. Three independent propensity-matched comparator patient cohorts were used. Plasma extracellular vesicles and multiplex serum cytokines were measured to assess inflammation and hepatic regeneration. Eighteen patients (9 moderate and 9 severe AH) were enrolled, 66% were male, and the mean age was 48 years. The half-life of F-652 following the first dose was 61-85 hours. There were no serious adverse events leading to discontinuation. The MELD score and serum aminotransferases decreased significantly at days 28 and 42 from baseline (P

Nonalcoholic fatty liver disease (NAFLD) is a heterogeneous group of liver diseases characterized by the accumulation of fat in the liver. The heterogeneity of NAFLD is reflected in a clinical and histologic spectrum where some patients develop isolated steatosis of the liver, termed nonalcoholic fatty liver, whereas others develop hepatocyte injury, ballooning, inflammation, and consequent fibrosis, termed nonalcoholic steatohepatitis (NASH). Systemic insulin resistance is a major driver of hepatic steatosis in NAFLD. Lipotoxicity of accumulated lipids along with activation of the innate immune system are major drivers of NASH. Lipid‐induced sublethal and lethal stress culminates in the activation of inflammatory processes, such as the release of proinflammatory extracellular vesicles and cell death. Innate and adaptive immune mechanisms involving macrophages, dendritic cells, and lymphocytes are central drivers of inflammation that recognize damage‐ and pathogen‐associated molecular patterns and contribute to the progression of the inflammatory cascade. While the activation of the innate immune system and the recruitment of proinflammatory monocytes into the liver in NASH are well known, the exact signals that lead to this remain less well defined. Further, the contribution of other immune cell types, such as neutrophils and B cells, is an area of intense research. Many host factors, such as the microbiome and gut–liver axis, modify individual susceptibility to NASH. In this review, we discuss lipotoxicity, inflammation, and the contribution of interorgan crosstalk in NASH pathogenesis., Lipotoxicity and inflammation are major pathogenic drivers of nonalcoholic steatohepatitis. Here we review the sublethal and lethal lipotoxic pathways activated in nonalcoholic steatohepatitis and the contribution of the immune system to liver inflammation.

Extracellular vesicles (EVs) are lipid bilayer particles secreted from various cells. EVs carry molecular information of parent cells and hold considerable promise for early disease diagnostics. This paper describes a general strategy for multiplexed immunosensing of EV surface proteins, focusing on surface markers CD63, CD81, nephrin, and podocin to prove the concept. This sensing strategy entailed functionalizing gold nanoparticles (AuNPs) with two types of antibodies and then tagging with metal ions, either Pb2+ or Cu2+. The metal ions served as redox reporters, generating unique redox peaks at -0.23 and 0.28 V (vs Ag/AgCl) during electrochemical oxidation of Pb2+ and Cu2+, respectively. Capture of EVs on the working electrode, followed by labeling with immunoprobes and square wave voltammetry, produced redox currents proportional to concentrations of EVs and levels of expression of EV surface markers. Importantly, metal-ion tagging of immunoprobes enabled detection of two EV surface markers simultaneously from the same electrode. We demonstrated dual detection of either CD63/CD81 or podocin/nephrin surface markers from urinary EVs. The NP-enabled immunoassay had a sensitivity of 2.46 × 105 particles/mL (or 40.3 pg/mL) for CD63- and 5.80 × 105 particles/mL (or 47.7 pg/mL) for CD81-expressing EVs and a linear range of four orders of magnitude. The limit of detection for podocin and nephrin was 3.1 and 3.8 pg/mL, respectively. In the future, the capacity for multiplexing may be increased by extending the repertoire of metal ions used for redox tagging of AuNPs.

There is increasing interest in the development of minimally invasive biomarkers for the diagnosis and prognosis of NAFLD via extracellular vesicles (EV). Plasma EVs were isolated by differential ultracentrifugation and quantified by nanoparticle tracking analysis from pre (n = 28) and post (n = 28) weight loss patients. In the pre weight loss group 22 had NAFLD. Nanoplasmon enhanced scattering (nPES) of gold nanoparticles conjugated to hepatocyte-specific antibodies was employed to identify hepatocyte-specific EVs. Complex lipid panel and targeted sphingolipids were performed. Logistic regression analysis was used to identify predictors of NAFLD. Plasma levels of EVs and hepatocyte-derived EVs are dynamic and decrease following NAFLD resolution due to weight loss surgery. Hepatocyte-derived EVs correlate with steatosis in NAFLD patients and steatosis and inflammation in NASH patients. Plasma levels of small EVs correlate with EV sphingolipids in patients with NASH. Hepatocyte-derived EVs measured by the nPES assay could serve as a point-of-care test for NAFLD.

Circulating extracellular vesicles (EVs) are a novel and emerging biomarker for nonalcoholic steatohepatitis (NASH). It has been demonstrated that total circulating EVs and hepatocyte‐derived EVs are elevated in male mice with diet‐induced NASH. How hepatocyte‐derived EVs change over time and other cellular sources of EVs in NASH have not been determined. Our objective was to define the quantitative evolution of hepatocyte‐derived, macrophage‐derived, neutrophil‐derived, and platelet‐derived EVs in male and female mice with dietary NASH. Fluorescently labeled antibodies and a nanoscale flow cytometer were used to detect plasma levels of EVs. Asialoglycoprotein receptor 1 (ASGR1) and cytochrome P450 family 2 subfamily E member 1 (CYP2E1) are markers of hepatocyte‐derived EVs; galectin 3 is a marker of macrophage‐derived EVs; common epitope on lymphocyte antigen 6 complex, locus G/C1 (Ly‐6G and Ly‐6C) is a marker of neutrophil‐derived EVs; and clusters of differentiation 61 (CD61) is a marker of platelet‐derived EVs. Nonalcoholic fatty liver disease activity score (NAS) was calculated using hematoxylin and eosin‐stained liver sections, and magnetic resonance imaging (MRI) was used for measurement of the fat fraction and elastography. Hepatocyte‐derived EVs increased in both male and female mice at 12 and 10 weeks of feeding, respectively, and remained elevated at 24 weeks in both male and female mice and at 48 weeks in male mice and 36 weeks in female mice. Macrophage‐ and neutrophil‐derived EVs were significantly elevated at 24 weeks of dietary feeding concomitant with the histologic presence of inflammatory foci in the liver. In fat‐, fructose‐, and cholesterol‐ (FFC) fed male mice, platelet‐derived EVs were elevated at 12, 24, and 48 weeks, whereas in female mice, platelet derived EVs were significantly elevated at 24 weeks. Hepatocyte‐, macrophage‐ and neutrophil‐derived EVs correlated well with the histologic NAS. Conclusion: Circulating cell‐type‐specific EVs may be a novel biomarker for NASH diagnosis and longitudinal follow up.

Nonalcoholic fatty liver disease is a major liver disease that leads to cirrhosis and/or hepatocellular carcinoma in a subset of patients. The mechanism underlying disease progression is largely unknown. p53-binding protein 1 (53BP1) is a DNA damage response protein that rapidly localizes at the site of DNA double-strand breaks. In this study, we investigated nuclear 53BP1-positive foci formation as an indicator of DNA double-strand breaks in human nonalcoholic fatty liver disease liver tissues by immunofluorescence microscopy. A total of 52 liver tissue samples, including 43 nonalcoholic fatty liver disease samples and 9 controls, were studied. Our results show that the number of abnormal 53BP1-positive foci in hepatocytes (defined as three or more discrete nuclear foci and/or large foci greater than 1 μM) was significantly increased in nonalcoholic fatty liver disease patients compared to that in controls, both in nonalcoholic fatty liver (p

Liver injury and the unfolded protein response (UPR) are tightly linked, but their relationship differs with cell type and injurious stimuli. UPR initiation promotes hepatic stellate cell (HSC) activation and fibrogenesis, but the underlying mechanisms are unclear. Despite the complexity and overlap downstream of UPR transducers inositol-requiring protein 1α (IRE1α), activating transcription factor 6α (ATF6α), and protein kinase RNA-like ER kinase (PERK), previous research in HSCs primarily focused on IRE1α. Here, we investigated the fibrogenic role of ATF6α or PERK in vitro and HSC-specific UPR signaling in vivo. Overexpression of ATF6α, but not the PERK effector activating transcription factor 4 (ATF4), promoted HSC activation and fibrogenic gene transcription in immortalized HSCs. Furthermore, ATF6α inhibition through Ceapin-A7, or Atf6a deletion, disrupted transforming growth factor β (TGFβ)-mediated activation of primary human hepatic stellate cells (hHSCs) or murine hepatic stellate cells (mHSCs), respectively. We investigated the fibrogenic role of ATF6α in vivo through conditional HSC-specific Atf6a deletion. Atf6a(HSCΔ/Δ) mice displayed reduced fibrosis and HSC activation following bile duct ligation (BDL) or carbon tetrachloride (CCl(4))-induced injury. The Atf6a(HSCΔ/Δ) phenotype differed from HSC-specific Ire1a deletion, as Ire1a(HSCΔ/Δ) mice showed reduced fibrogenic gene transcription but no changes in fibrosis compared with Ire1a(fl/fl) mice following BDL. Interestingly, ATF6α signaling increased in Ire1a(Δ/Δ) HSCs, whereas IRE1α signaling was upregulated in Atf6a(Δ/Δ) HSCs. Finally, we asked whether co-deletion of Atf6a and Ire1a additively limits fibrosis. Unexpectedly, fibrosis worsened in Atf6a(HSCΔ/Δ)Ire1a(HSCΔ/Δ) mice following BDL, and Atf6a(Δ/Δ)Ire1a(Δ/Δ) mHSCs showed increased fibrogenic gene transcription. ATF6α and IRE1α individually promote fibrogenic transcription in HSCs, and ATF6α drives fibrogenesis in vivo. Unexpectedly, disruption of both pathways sensitizes the liver to fibrogenesis, suggesting that fine-tuned UPR signaling is critical for regulating HSC activation and fibrogenesis. NEW & NOTEWORTHY ATF6α is a critical driver of hepatic stellate cell (HSC) activation in vitro. HSC-specific deletion of Atf6a limits fibrogenesis in vivo despite increased IRE1α signaling. Conditional deletion of Ire1α from HSCs limits fibrogenic gene transcription without impacting overall fibrosis. This could be due in part to observed upregulation of the ATF6α pathway. Dual loss of Atf6a and Ire1a from HSCs worsens fibrosis in vivo through enhanced HSC activation.

BACKGROUND AND AIMS Alcoholic hepatitis (AH) is diagnosed by clinical criteria, although several objective scores facilitate risk stratification. Extracellular vesicles (EVs) have emerged as biomarkers for many diseases and are also implicated in the pathogenesis of AH. Therefore, we investigated whether plasma EV concentration and sphingolipid cargo could serve as diagnostic biomarkers for AH and inform prognosis to permit dynamic risk profiling of AH subjects. APPROACH AND RESULTS EVs were isolated and quantified from plasma samples from healthy controls, heavy drinkers, and subjects with end-stage liver disease (ESLD) attributed to cholestatic liver diseases and nonalcoholic steatohepatitis, decompensated alcohol-associated cirrhosis (AC), and AH. Sphingolipids were quantified by tandem mass spectroscopy. The median plasma EV concentration was significantly higher in AH subjects (5.38 × 1011 /mL) compared to healthy controls (4.38 × 1010 /mL; P

Background/Aims Hypothyroidism has been associated with hepatocellular carcinoma (HCC) incidence; however, the relationship between hypothyroidism and HCC patient outcomes is unclear. We investigated the impact of hypothyroidism on outcomes after liver transplantation for HCC. Materials and Methods We retrospectively studied HCC patients transplanted between January 2000 and December 2015. Hypothyroidism was defined as a thyroid‐stimulating hormone (TSH) level continuously greater than 5 mIU/L, a documented history of hypothyroidism, or treatment with thyroid hormone replacement therapy. Multivariate Cox regression was used to assess the impact of hypothyroidism on overall survival (OS) and recurrence‐free survival (RFS) adjusting for potential confounders. Subgroup analyses and interaction tests were conducted to compare the impact of hypothyroidism in different subgroups and assess for possible synergistic effects. Sensitivity analyses were performed among different cohorts to verify the stability of the results. Results A total of 343 HCC patients who underwent liver transplantation were included in the analysis. The primary analysis was conducted among 288 patients diagnosed with HCC prior to transplantation. Hypothyroidism was independently associated with worse OS and RFS, as was elevated TSH. The adjusted hazard ratio (AHR) of hypothyroidism was 2.45 (95% confidence interval [CI], 1.44‐4.18) for OS and 5.54 (2.36, 13.01) for RFS. The AHR of TSH for OS was 1.05 (1.02, 1.09) and 1.08 (1.03, 1.13) for RFS. No interaction was found among different subgroups categorized by etiology and comorbidity. The results were stable to sensitivity analyses. Conclusion Hypothyroidism is associated with poorer overall and recurrence‐free survival of HCC patients receiving liver transplantation. These results require validation.

Aim Activation of PKR-like endoplasmic reticulum kinase (PERK), an endoplasmic reticulum stress sensor, is a feature of non-alcoholic steatohepatitis (NASH), yet regulators of PERK signaling remain undefined in this context. The protein p58IPK regulates PERK; however, its role in NASH has not been examined. The aim of this study was to assess the in vivo role of p58IPK in the pathogenesis of dietary NASH. Methods Parameters of hepatocyte cell death, liver injury, inflammation, fibrosis, indirect calorimetry and PERK activation were assessed in p58IPK knockout (p58ipk-/- ) mice and their wild-type littermate controls. All animals were fed a diet enriched in fat, fructose, and cholesterol (FFC) for 20 weeks. Results Activation of PERK was attenuated in FFC-fed p58ipk-/- mice. Accordingly, FFC-fed p58ipk-/- mice showed a reduction in hepatocyte apoptosis and death receptor expression, with a significant reduction in serum alanine transaminase values. Correspondingly, macrophage accumulation and fibrosis were significantly lower in FFC-fed p58ipk-/- mice. Conclusion We have shown that, in an in vivo dietary NASH model, p58IPK mediates hepatocyte apoptosis and liver injury, likely through PERK phosphorylation. In the absence of p58IPK , PERK phosphorylation and NASH are attenuated. Inhibition of hepatic p58IPK could be a future target for NASH therapy.

We thank Arora et al. for their interest in our study. They comment on the limitations of our study which proposes the use of extracellular vesicles (EVs) and associated sphingolipid cargo as a novel biomarker for alcoholic hepatitis (AH) and reiterate our own conclusion for the need of validation of our findings in a larger cohort.

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. Up to one third of individuals with NAFLD will develop nonalcoholic steatohepatitis (NASH), which is associated with progression to cirrhosis and is rapidly becoming the leading indication for liver transplantation. Sarcopenia is defined as a progressive and generalized loss of skeletal muscle mass, strength, and function. It is observed in up to 60% of patients with end-stage liver disease and portends a poor prognosis. Recent studies have shown that sarcopenia is a novel risk factor for developing NAFLD. Pathophysiological mechanisms relating sarcopenia and NASH may include insulin resistance (IR) and increased inflammation. IR leads to accumulation of triglycerides in both muscle tissue and the liver. It also exacerbates proteolysis and leads to muscle depletion. Chronic inflammation leads to liver injury and progression of fibrosis. The inflammatory milieu also stimulates protein catabolism. Viewing skeletal muscle as an endocrine organ that secretes various salutary myokines may help us understand its role in the development of steatosis. A better understanding of the pathophysiology will aid in developing physical and pharmacological therapeutic interventions. In this review, we will explore the complex inter-relationships between sarcopenia and NASH. We will discuss the impact of sarcopenia in patients with NASH and therapeutic options for the management of sarcopenia. (Hepatology 2017;66:2055-2065).

Extracellular vesicles (EVs) are membrane-defined nanoparticles released by most cell types. The EVs released by cells may differ quantitatively and qualitatively from physiological states to disease states. There are several unique properties of EVs, including their proteins, lipids and nucleic acid cargoes, stability in circulation, and presence in biofluids, which make them a critical vector for cell-to-cell communication and impart utility as a biomarker. EVs may also serve as a vehicle for selective cargo secretion. Similarly, EV cargo may be selectively manipulated for targeted therapeutic delivery. In this review an overview is provided on the EV classification, biogenesis, and secretion pathways, which are conserved across cell types. Next, cargo characterization and effector cell responses are discussed in the context of nonalcoholic steatohepatitis, alcoholic hepatitis, and acetaminophen-induced liver injury. The review also discusses the potential biomarker and therapeutic uses of circulating EVs.

Endoplasmic reticulum (ER) stress is a major contributor to liver disease and hepatic fibrosis, but the role it plays varies depending on the cause and progression of the disease. Furthermore, ER stress plays a distinct role in hepatocytes versus hepatic stellate cells (HSCs), which adds to the complexity of understanding ER stress and its downstream signaling through the unfolded protein response (UPR) in liver disease. Here, the authors focus on the current literature of ER stress in nonalcoholic and alcoholic fatty liver diseases, how ER stress impacts hepatocyte injury, and the role of ER stress in HSC activation and hepatic fibrosis. This review provides insight into the complex signaling and regulation of the UPR, parallels and distinctions between different liver diseases, and how ER stress may be targeted as an antisteatotic or antifibrotic therapy to limit the progression of liver disease.

Extracellular vesicles (EVs) are nanometer-sized, membrane-bound vesicles released by cells into the extracellular milieu. EVs are now recognized to play a critical role in cell-to-cell communication. EVs contain important cargo in the form of proteins, lipids, and nucleic acids and serve as vectors for delivering this cargo from donor to acceptor or target cell. EVs are released under both physiologic and pathologic conditions, including liver diseases, and exert a wide range of effects on target cells. This review provides an overview on EV biogenesis, secretion, cargo, and target cell interactions in the context of select liver diseases. Specifically, the diverse roles of EVs in nonalcoholic steatohepatitis, alcoholic liver disease, viral hepatitis, cholangiopathies, and hepatobiliary malignancies are emphasized. Liver diseases often result in an increased release of EVs and/or in different cargo sorting into these EVs. Either of these alterations can drive disease pathogenesis. Given this fact, EVs represent a potential target for therapeutic intervention in liver disorders. Because altered EV composition may reflect the underlying disease condition, circulating EVs can be exploited for diagnostic and prognostic purposes as a liquid biopsy. Furthermore, ex vivo modified or synthesized EVs can be engineered as therapeutic nano-shuttles. Finally, we highlight areas that merit further investigation relevant to understanding how EVs regulate liver disease pathogenesis. (Hepatology 2016;64:2219-2233).