The emerging roles of microvesicles in liver diseases

Microvesicle Tissue Factor Procoagulant Activity Is Elevated and Correlated With Disease Severity in Patients With Cirrhosis

BACKGROUND AND AIMS

Tissue factor-expressing microvesicles (MV-TF) have been found to correlate with thrombotic complications in various diseases. Simultaneously, there is expanding research regarding the effect of the coagulation cascade on liver fibrosis progression. The aim of our manuscript was to evaluate MV-TF activity in patients with cirrhosis and its correlation with disease severity.

METHODS

We prospectively enrolled 82 patients [11 with cirrhosis and hepatocellular cancer (Group 1), 50 with cirrhosis (Group 2) and 21 controls (Group 3)]. Extensive workup for disease staging and exclusion criteria was undertaken. Exclusion criteria included thrombophilia, history of thrombosis, recent hospitalisation, ongoing infection, alcohol dependence, cancer, haematological diseases and use of anticoagulant, antiplatelet or contraceptive drugs. Plasma tissue factor antigen concentration and MV-TF activity were assessed.

RESULTS

MV-TF showed median values of 4.03 [1.57], 3.17 [1.59] and 2.26 [1.23] pg/mL in Groups 1, 2 and 3, respectively. There was a statistically significant difference between Groups 1 and 3 (p < 0.001) and Groups 2 and 3 (p = 0.003), while Group 1 had higher values than Group 2 without statistical significance (p = 0.088). In Group 2, the patients' Child-Pugh (CP) stage was A in 56%, B in 26% and C in 18% of cases. MV-TF activity significantly correlated with decompensated cirrhosis (p = 0.005) and higher CP stage (p = 0.011). Finally, MV-TF activity significantly correlated with 12-month mortality (p = 0.021).

CONCLUSIONS

MV-TF activity is elevated in patients with cirrhosis, showing a significant correlation with disease severity. MV-TF may play a role in the procoagulant imbalance of liver cirrhosis and their contribution in disease progression should be studied further.

Molecular regulators of alcoholic liver disease: a comprehensive analysis of microRNAs and long non-coding RNAs

Many biomolecules and signaling pathways are involved in the development of alcoholic liver disease (ALD). The molecular mechanisms of ALD are not fully understood and there is no effective treatment. Numerous studies have demonstrated the critical role of non-coding RNAs, including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), in ALD. miRNAs play an important regulatory role in the pathogenesis of ALD by controlling critical biological processes such as inflammation, oxidative stress, lipid metabolism, apoptosis and fibrosis. Among them, miR-155, miR-223 and miR-34a play a central role in these processes and influence the pathological process of ALD. In addition, lncRNAs are involved in regulating liver injury and repair by interacting with miRNAs to form a complex regulatory network. These findings help to elucidate the molecular mechanisms of ALD and provide a scientific basis for the development of new diagnostic markers and therapeutic targets. In this article, we review the roles and mechanisms of LncRNAs and miRNAs in ALD and their potential use as diagnostic markers and therapeutic targets.

Sinusoidal communication in chronic liver disease

The liver sinusoid, mainly composed of liver sinusoidal endothelial cells, hepatic macrophages and hepatic stellate cells, shapes the hepatic vasculature and is key to maintaining liver homeostasis and function. During chronic liver disease (CLD), the function of sinusoidal cells is impaired, being directly involved in the progression of liver fibrosis, cirrhosis, and main clinical complications including portal hypertension and hepatocellular carcinoma. In addition to their roles in liver diseases pathobiology, sinusoidal cells' paracrine communication or cross-talk is being studied as a mechanism of disease but also as a remarkable target for treatment. The aim of this review is to gather current knowledge of intercellular signalling in the hepatic sinusoid during the progression of liver disease. We summarise studies developed in pre-clinical models of CLD, especially emphasizing those pathways characterized in human-based clinically relevant models. Finally, we describe pharmacological treatments targeting sinusoidal communication as promising options to treat CLD and its clinical complications.

MicroRNAs in extracellular vesicles: A potential role in cancer progression

Intercellular communication, an essential biological process in multicellular organisms, is mediated by direct cell-to-cell contact and cell secretary molecules. Emerging evidence identifies a third mechanism of intercellular communication- the release of extracellular vesicles (EVs). EVs are membrane-enclosed nanosized bodies, released from cells into the extracellular environment, often found in all biofluids. The growing body of research indicates that EVs carry bioactive molecules in the form of proteins, DNA, RNAs, microRNAs (miRNAs), lipids, metabolites, etc., and upon transferring them, alter the phenotypes of the target recipient cells. Interestingly, the abundance of EVs is found to be significantly higher in different diseased conditions, most importantly cancer. In the past few decades, numerous studies have identified EV miRNAs as an important contributor in the pathogenesis of different types of cancer. However, the underlying mechanism behind EV miRNA-associated cancer progression and how it could be used as a targeted therapy remain ill-defined. The present review highlights how EV miRNAs influence essential processes in cancer, such as growth, proliferation, metastasis, angiogenesis, apoptosis, stemness, immune evasion, resistance to therapy, etc. A special emphasis has been given to the potential role of EV miRNAs as cancer biomarkers. The final section of the review delineates the ongoing clinical trials on the role of miRNAs in the progression of different types of cancer. Targeting EV miRNAs could be a potential therapeutic means in the treatment of different forms of cancer alongside conventional therapeutic approaches.

MicroRNA-223-3p levels in serum-derived extracellular vesicles predict regression of M2BPGi-based liver fibrosis after hepatitis C virus eradication by direct-acting antiviral agents

BACKGROUND

We retrospectively investigated microRNA (miRNA) levels in serum-derived extracellular vesicles (EVs) as predictive indicators for regression of liver fibrosis, after achievement of a sustained virological response (SVR) by direct-acting antiviral (DAA) therapy for chronic hepatitis C (CHC).

METHODS

The study subjects were recruited from a historical cohort of 108 CHC patients whose pretreatment serum Mac-2-binding protein glycosylation isomer (M2BPGi) levels were ≥ 2.0 cut-off index (COI). We classified patients with M2BPGi levels < 1.76 and ≥ 1.76 COI at 2 years after the end of treatment (EOT) into the regression and non-regression groups, respectively. Eleven of the patients were assigned to the discovery set, and we comprehensively investigated the miRNAs contained in serum-derived EVs at 24 weeks after the EOT (EOT24W), using RNA sequencing. The remaining 97 patients were assigned to the validation set, and reproducibility was verified by quantitative real-time PCR.

RESULTS

Through analysis of the discovery and validation sets, we identified miR-223-3p and miR-1290 as candidate predictors. Subsequently, we analyzed various clinical data, including these candidate miRNAs. Multivariate analyses revealed that the levels of miR-223-3p at EOT24W were significantly associated with regression of M2BPGi-based liver fibrosis (Odds ratio: 1.380; P = 0.024). Consistent results were obtained, even when the serum M2BPGi levels were aligned by propensity score matching and in patients with advanced M2BPGi-based liver fibrosis (pretreatment M2BPGi levels ≥ 3.3 COI).

CONCLUSIONS

The miR-223-3p level in serum-derived EVs at EOT24W is a feasible predictor of regression of M2BPGi-based liver fibrosis after achievement of an SVR by DAA therapy.

Clinical significance of small extracellular vesicles in cholangiocarcinoma

Cholangiocarcinoma is an aggressive and heterogeneous malignancy originating from the bile duct epithelium. It is associated with poor prognosis and high mortality. The global incidence of cholangiocarcinoma is rising, and there is an urgent need for effective early diagnosis and treatment strategies to reduce the burden of this devastating tumor. Small extracellular vesicles, including exosomes and microparticles, are nanoscale vesicles formed by membranes that are released both normally and pathologically from cells, mediating the intercellular transfer of substances and information. Recent studies have demonstrated the involvement of small extracellular vesicles in numerous biological processes, as well as the proliferation, invasion, and metastasis of tumor cells. The present review summarizes the tumorigenic roles of small extracellular vesicles in the cholangiocarcinoma microenvironment. Owing to their unique composition, accessibility, and stability in biological fluids, small extracellular vesicles have emerged as ideal biomarkers for use in liquid biopsies for diagnosing and outcome prediction of cholangiocarcinoma. Specific tissue tropism, theoretical biocompatibility, low clearance, and strong biological barrier penetration of small extracellular vesicles make them suitable drug carriers for cancer therapy. Furthermore, the potential value of small extracellular vesicle-based therapies for cholangiocarcinoma is also reviewed.

Efficacy and safety of atezolizumab plus bevacizumab in patients with portal hypertension for unresectable hepatocellular carcinoma

AIM

Atezolizumab plus bevacizumab combination therapy (Atezo + Beva) is used as the first-line therapy for unresectable hepatocellular carcinoma (u-HCC). Serious adverse events (AEs), including rupture of esophagogastric varices, have been seen during treatment. Therefore, the relationships of efficacy, safety, and portal hypertension (PH) were analyzed.

METHODS

A total of 146 patients with u-HCC and Child-Pugh Scores of 5-7 received Atezo + Beva. Prophylactic treatment for varices was performed for patients with the risk of rupture of varices before the start of Atezo + Beva. A propensity score-matched cohort was created to minimize the risk of potential confounders. Efficacy was assessed in 41 propensity score-matched pairs. AEs were assessed between patients without PH (n = 80) and with PH (n = 66).

RESULTS

In patients without PH and with PH, median overall survival was 18.4 months and 18.8 months (p = 0.71), and median progression-free survival was 8.6 months and 5.8 months (p = 0.92), respectively. On the best radiological response evaluation for Response Evaluation Criteria in Solid Tumors, the objective response rate was 31.7% and 26.8% (p = 0.81), respectively. Variceal rupture occurred in three patients with PH, but there were no significant differences in the occurrence of variceal rupture (p = 0.090) and Grade 3-4 AEs between patients without and with PH.

CONCLUSIONS

No significant differences in efficacy and safety were observed with PH. Prophylactic treatment for varices before the start of Atezo + Beva would allow treatment to continue relatively safely.

Clinical significance of exosomal noncoding RNAs in hepatocellular carcinoma: a narrative review

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies worldwide, with poor prognosis owing to its high frequency of recurrence and metastasis. Moreover, most patients are diagnosed at an advanced stage owing to a lack of early detection markers. Exosomes, which are characterized by their cargos of stable intracellular messengers, such as DNA, RNA, proteins, and lipids, play a crucial role in regulating cell differentiation and HCC development. Recently, exosomal noncoding RNAs (ncRNAs), including microRNAs, long ncRNAs, and circular RNAs, have become increasingly important diagnostic, prognostic, and predictive markers of HCC. Herein, we discuss the clinical implications of exosomal ncRNAs, specifically those within the HCC regulatory network.

The role of extracellular vesicles in cholangiocarcinoma tumor microenvironment

Cholangiocarcinoma (CCA) is a highly aggressive malignant tumor that originates from the biliary system. With restricted treatment options at hand, the challenging aspect of early CCA diagnosis leads to a bleak prognosis. Besides the intrinsic characteristics of tumor cells, the generation and progression of CCA are profoundly influenced by the tumor microenvironment, which engages in intricate interactions with cholangiocarcinoma cells. Of notable significance is the role of extracellular vesicles as key carriers in enabling communication between cancer cells and the tumor microenvironment. This review aims to provide a comprehensive overview of current research examining the interplay between extracellular vesicles and the tumor microenvironment in the context of CCA. Specifically, we will emphasize the significant contributions of extracellular vesicles in molding the CCA microenvironment and explore their potential applications in the diagnosis, prognosis assessment, and therapeutic strategies for this aggressive malignancy.

Serum α-SMA is a potential noninvasive biomarker of liver fibrosis

The severity of fibrosis is central to the therapeutic course for patients with chronic liver disease; therefore, early detection of liver fibrosis is critical for timely therapeutic interventions. Liver biopsy is the gold standard for the diagnosis of liver fibrosis; however, it is contraindicated in several pathological conditions. Activated hepatic stellate cells (HSCs) are the main cells for fibrotic tissue synthesis, such as that of alpha-smooth muscle actin (α-SMA). This study aimed to determine whether serum α-SMA levels are a suitable noninvasive, sensitive, and reliable liver fibrosis marker. Fibrosis was induced in male Wistar rats via chronic CCl4 administration. Fibrosis was determined in the liver tissues by quantifying the hydroxyproline content and visualized using Masson's trichrome staining. Rats chronically administered CCl4 exhibited a progressive increment in the hepatic collagen content, as well as both hepatic and serum α-SMA levels in a time-dependent manner. Moreover, serum levels of α-SMA significantly correlated with hepatic α-SMA levels (p ≤ 0.001), as well as with the severity of liver fibrosis (p ≤ 0.001). These findings suggest that increased levels of serum α-SMA can be considered a potential reliable and noninvasive biomarker for early liver fibrosis.

The promise of small particles: extracellular vesicles as biomarkers in liver pathology

Extracellular vesicles (EVs) are nanoscopic packages that are heterogeneous and bona fide players in hepatic physiology and pathology as they are involved in intercellular communication. EVs carrying bioactive cargoes rich in lipids, proteins or nucleic acids are implicated in the onset and progression of liver diseases. Liver pathology using liver biopsy has been assessed for several intricate conditions such as viral hepatitis, alcoholic and non-alcoholic fatty liver disease, hepatic malignancies and drug-induced liver injury. The lacunae, however, lie in early diagnosis and timely treatment of the above conditions, underscoring the need for non-invasive, accurate diagnostic tools that could replace the gold standard method of tissue biopsy. In this regard, EVs have emerged as promising candidates that could serve as potential biomarkers. In the last two decades, EVs, owing to their multifaceted charm in bringing out cell-free therapeutic responses and the ability of their cargoes to be applied to novel biomarkers, have drawn the great attention of researchers with the advancement and clinical application of liquid biopsy. In this review, we recapitulate the role of EVs and provide insights into the promising role of these small packages as biomarkers in liver pathology.

Role of EpCAM+ CD133+ extracellular vesicles in steatosis to steatohepatitis transition in NAFLD

BACKGROUND AND AIMS

Extracellular vesicles (EVs) have emerged as a potential source of circulating biomarkers in liver disease. We evaluated circulating AV+ EpCAM+ CD133+ EVs as a potential biomarker of the transition from simple steatosis to steatohepatitis.

METHODS

EpCAM and CD133 liver proteins and EpCAM+ CD133+ EVs levels were analysed in 31 C57BL/6J mice fed with a chow or high fat, high cholesterol and carbohydrates diet (HFHCC) for 52 weeks. The hepatic origin of MVs was addressed using AlbCrexmT/mG mice fed a Western (WD) or Dual diet for 23 weeks. Besides, we assessed plasma MVs in 130 biopsy-proven NAFLD patients.

RESULTS

Hepatic expression of EpCAM and CD133 and EpCAM+ CD133+ EVs increased during disease progression in HFHCC mice. GFP+ MVs were higher in AlbCrexmT/mG mice fed a WD (5.2% vs 12.1%) or a Dual diet (0.5% vs 7.3%). Most GFP+ MVs were also positive for EpCAM and CD133 (98.3% and 92.9% respectively), suggesting their hepatic origin. In 71 biopsy-proven NAFLD patients, EpCAM+ CD133+ EVs were significantly higher in those with steatohepatitis compare to those with simple steatosis (286.4 ± 61.9 vs 758.4 ± 82.3; p < 0.001). Patients with ballooning 367 ± 40.6 vs 532.0 ± 45.1; p = 0.01 and lobular inflammation (321.1 ± 74.1 vs 721.4 ± 80.1; p = 0.001), showed higher levels of these EVs. These findings were replicated in an independent cohort.

CONCLUSIONS

Circulating levels of EpCAM+ CD133+ MVs in clinical and experimental NAFLD were increased in the presence of steatohepatitis, showing high potential as a non-invasive biomarker for the evaluation and management of these patients.

Liver fibrosis-derived exosomal miR-106a-5p facilitates the malignancy by targeting SAMD12 and CADM2 in hepatocellular carcinoma

The mechanism of hepatocellular carcinoma (HCC) development induced by liver fibrosis is obscure. The objective of this study is to establish miRNAs from exosomes associated with liver fibrosis, and to identify potential biomarkers for the prediction of personalized clinical management effectiveness in HCC. Our research focused on miRNAs from exosomes and mRNA from liver fibrosis, which we found in the gene expression omnibus (GEO) database. Weighted gene co-expression network analysis (WGCNA) evaluated miRNAs from exosomes associated with liver fibrosis, and Wilcoxon analysis assessed differentially expressed mRNAs (DEGs) across liver fibrosis/normal tissues. Following that, DEGs were assessed through gene set enrichment analysis (GSEA), gene ontology (GO), and the Kyoto Encyclopedia of Genes and Genomes (KEGG). In addition, based on the screened targeted genes, including SAMD12 and CADM2, we further elucidated their correlation in HCC patients from the BEST database. The Kaplan-Meier Plotter platform was applied to evaluate the prognostic values of miRNA in HCC. In vitro and vivo experiments validated our findings. Six miRNAs associated with liver fibrosis were evaluated in our investigation. In-depth research presented exosome-derived miR-106a-5p, SAMD12 and CADM2 could exert valuable predictive implications for HCC treatment and illness assessment. Serum miR-106a-5p derived from liver fibrosis was decreased compared with healthy individuals. SAMD12 and CADM2 were diminished in liver cancer cell lines, and their knockdown of them exacerbated the proliferation capacities of liver cells in vitro. Exosome-derived miRNA of liver fibrosis modulated tumorigenesis by targeting SAMD12 and CADM2 in HCC.

CINC-2 and miR-199a-5p in EVs secreted by transplanted Thy1+ cells activate hepatocytic progenitor cell growth in rat liver regeneration

BACKGROUND

Small hepatocyte-like progenitor cells (SHPCs) are hepatocytic progenitor cells that transiently form clusters in rat livers treated with retrorsine (Ret) that underwent 70% partial hepatectomy (PH). We previously reported that transplantation of Thy1⁺ cells obtained from D-galactosamine-treated livers promotes SHPC expansion, thereby accelerating liver regeneration. Extracellular vesicles (EVs) secreted by Thy1⁺ cells induce sinusoidal endothelial cells (SECs) and Kupffer cells (KCs) to secrete IL17B and IL25, respectively, thereby activating SHPCs through IL17 receptor B (RB) signaling. This study aimed to identify the inducers of IL17RB signaling and growth factors for SHPC proliferation in EVs secreted by Thy1⁺ cells (Thy1-EVs).

METHODS

Thy1⁺ cells isolated from the livers of rats treated with D-galactosamine were cultured. Although some liver stem/progenitor cells (LSPCs) proliferated to form colonies, others remained as mesenchymal cells (MCs). Thy1-MCs or Thy1-LSPCs were transplanted into Ret/PH-treated livers to examine their effects on SHPCs. EVs were isolated from the conditioned medium (CM) of Thy1-MCs and Thy1-LSPCs. Small hepatocytes (SHs) isolated from adult rat livers were used to identify factors regulating cell growth in Thy1-EVs.

RESULTS

The size of SHPC clusters transplanted with Thy1-MCs was significantly larger than that of SHPC clusters transplanted with Thy1-LSPCs (p = 0.02). A comprehensive analysis of Thy1-MC-EVs revealed that miR-199a-5p, cytokine-induced neutrophil chemoattractant-2 (CINC-2), and monocyte chemotactic protein 1 (MCP-1) were candidates for promoting SHPC growth. Additionally, miR-199a-5p mimics promoted the growth of SHs (p = 0.02), whereas CINC-2 and MCP-1 did not. SECs treated with CINC-2 induced Il17b expression. KCs treated with Thy1-EVs induced the expression of CINC-2, Il25, and miR-199a-5p. CM derived from SECs treated with CINC-2 accelerated the growth of SHs (p = 0.03). Similarly, CM derived from KCs treated with Thy1-EVs and miR-199a-5p mimics accelerated the growth of SHs (p = 0.007). In addition, although miR-199a-overexpressing EVs could not enhance SHPC proliferation, transplantation of miR-199a-overexpressing Thy1-MCs could promote the expansion of SHPC clusters.

CONCLUSION

Thy1-MC transplantation may accelerate liver regeneration owing to SHPC expansion, which is induced by CINC-2/IL17RB signaling and miR-199a-5p via SEC and KC activation.

Vascular Extracellular Vesicles Indicate Severe Hepatopulmonary Syndrome in Cirrhosis

Background: Hepatopulmonary syndrome (HPS) is a pulmonary vasculature complication in the setting of liver disease that is characterized by pathological vasodilation resulting in arterial oxygenation defects. We investigated the role of extracellular vesicles (EV) in cirrhosis patients with HPS, as well as the functional effect of EV administration in a common bile duct ligation (CBDL) HPS mouse model. Methods: A total of 113 cirrhosis patients were studied: 42 (Gr. A) with HPS and 71 (Gr. B) without HPS, as well as 22 healthy controls. Plasma levels of EV associated with endothelial cells, epithelial cells, and hepatocytes were measured. The cytokine cargoes were estimated using ELISA. The effect of EV administered intranasally in the CBDL mouse model was investigated for its functional effect in vascular remodeling and inflammation. Results: We found endothelial cells (EC) associated EV (EC-EV) were elevated in cirrhosis patients with and without HPS (p < 0.001) than controls. EC-EV levels were higher in HPS patients (p = 0.004) than in those without HPS. The epithelial cell EVs were significantly high in cirrhosis patients than controls (p < 0.001) but no changes found in patients with HPS than without. There was a progressive increase in EC-EV levels from mild to severe intrapulmonary shunting in HPS patients (p = 0.02 mild vs. severe), and we were able to predict severe HPS with an AUROC of 0.85; p < 0.001. An inverse correlation of EC-EVs was found with hemoglobin (r = −0.24; p = 0.031) and PaO2 (r = 0.690; p = 0.01) and a direct correlation with MELD (r = 0.32; p = 0.014). Further, both TNF-α (p = 0.001) and IL-1β (p = 0.021) as cargo levels were significantly elevated inside the EVs of HPS patients than without HPS. Interestingly, upon administration of intranasal EVs, there was a significant decrease in Evans blue accumulation and lung wet–dry ratio (p = 0.042; 0.038). A significant reduction was also noticed in inflammation and cholestasis. Conclusion: High levels of plasma EC-EV levels were found in patients with HPS with elevated pro-inflammatory cytokine cargoes. EC-EVs were indicative of severe HPS condition. In the CBDL HPS model, we were able to prove the beneficial effects of improving vascular tone, inflammation, and liver pathogenesis.

Characterization and microRNA Expression Analysis of Serum-Derived Extracellular Vesicles in Severe Liver Injury from Chronic HBV Infection

BACKGROUND

Extracellular vesicle (EV) microRNAs have been documented in several studies to have significantly different expressions in hepatitis B virus (HBV)-related liver diseases, such as hepatocellular carcinoma (HCC). The current work aimed to observe the characteristics of EVs and EV miRNA expressions in patients with severe liver injury chronic hepatitis B (CHB) and patients with HBV-associated decompensated cirrhosis (DeCi).

METHODS

The characterization of the EVs in the serum was carried out for three different groups, namely, patients with severe liver injury-CHB, patients with DeCi, and healthy controls. EV miRNAs were analyzed using miRNA-seq and RT-qPCR arrays. Additionally, we assessed the predictive and observational values of the miRNAs with significant differential expressions in serum EVs.

RESULTS

Patients with severe liver injury-CHB had the highest EV concentrations when compared to the normal controls (NCs) and patients with DeCi (p < 0.001). The miRNA-seq of the NC and severe liver injury-CHB groups identified 268 differentially expressed miRNAs (|FC| > 2, p < 0.05). In this case, 15 miRNAs were verified using RT-qPCR, and it was found that novel-miR-172-5p and miR-1285-5p in the severe liver injury-CHB group showed marked downregulation in comparison to the NC group (p < 0.001). Furthermore, compared with the NC group, three EV miRNAs (novel-miR-172-5p, miR-1285-5p, and miR-335-5p) in the DeCi group showed various degrees of downregulated expression. However, when comparing the DeCi group with the severe liver injury-CHB group, only the expression of miR-335-5p in the DeCi group decreased significantly (p < 0.05). For the severe liver injury-CHB and DeCi groups, the addition of miR-335-5p improved the predictive accuracy of the serological levels, while miR-335-5p was significantly correlated with ALT, AST, AST/ALT, GGT, and AFP. Conclusions: The patients with severe liver injury-CHB had the highest number of EVs. The combination of novel-miR-172-5p and miR-1285-5p in serum EVs helped in predicting the progression of the NCs to severe liver injury-CHB, while the addition of EV miR-335-5p improved the serological accuracy of predicting the progression of severe liver injury-CHB to DeCi.

Non-invasive methods to evaluate liver fibrosis in patients with non-alcoholic fatty liver disease

Non-alcoholic Fatty Liver Disease (NAFLD) is a chronic liver disease that is strongly related to insulin resistance and metabolic syndrome, and it has become the most common liver disorder in developed countries. NAFLD embraces the full pathological process of three conditions: steatosis, non-alcoholic steatohepatitis, and finally, cirrhosis. As NAFLD progresses, symptoms will become increasingly severe as fibrosis develops. Therefore, evaluating the fibrosis stage is crucial for patients with NAFLD. A liver biopsy is currently considered the gold standard for staging fibrosis. However, due to the limitations of liver biopsy, non-invasive alternatives were extensively studied and validated in patients with NAFLD. The advantages of non-invasive methods include their high safety and convenience compared with other invasive approaches. This review introduces the non-invasive methods, summarizes their benefits and limitations, and assesses their diagnostic performance for NAFLD-induced fibrosis.

Diagnosis of portal vein thrombosis in cirrhotic patients with and without hepatocellular carcinoma

Background

The levels of Annexin A5 (Annexin V) were measured in patients with and without HCC who had liver cirrhosis. These patients were followed for 12 months to determine the incidence of PVT and to determine the role of Annexin V in the diagnosis of PVT. Our goal was to look at the value of Annexin A5, platelet count, spleen size, portal flow velocity, portal vein width, Fibrosis 4, and APRI score in these individuals to see if they might be used as PVT markers.

Methods

Between March 2017 and August 2018, ninety-one HCV patients with cirrhosis with and without HCC, as well as a control group of twenty healthy people, were included in this longitudinal study at the NHTMRI. The blood anxA5 level was determined using a commercial Hyphen BioMed immunoassay using Stat Fax 4700’s Microstrip Reader l.

Results

Cirrhotic patients with and without HCC who developed PVT had higher Annexin A5 scales (5.75 + 0.18), compared to cirrhotic patients who did not develop PVT (3.63 + 1.08 (P 0.001). PVT was 20% in all cirrhotic patients after a year, 15% in cirrhotic patients without HCC, and 25% in cirrhotic patients with HCC. Cirrhotic patients who had PVT throughout the follow-up period had greater AnxA5 serum levels than cirrhotic patients who did not develop PVT.

Conclusions

In all cirrhotic patients, AnxA5 level, platelet count, spleen size, portal flow velocity, portal vein diameter, and Fibrosis 4 score might be employed as markers for PVT development.

Upregulation of miR-664a-3p Ameliorates Calcific Aortic Valve Disease by Inhibiting the BMP2 Signaling Pathway

The development of calcific aortic valve disease (CAVD) is a complex process of ectopic calcification involving various factors that lead to aortic valve stenosis, hemodynamic changes, and, in severe cases, even sudden death. Currently, aortic valve replacement is the only effective method. The osteogenic differentiation of aortic valve interstitial cells (AVICs) is one of the key factors of valve calcification. Emerging evidence suggests that bone morphogenetic protein 2 (BMP2) can induce the proosteogenic activation of AVICs. However, the regulatory mechanism underlying this activation in AVICs is unclear. In the present study, we elucidated through high-throughput RNA sequencing and RT-qPCR that miR-664a-3p was evidently downregulated in the calcific aortic valve. We also proved that miR-664a-3p was involved in regulating osteogenic differentiation in AVICs. Target prediction analysis and dual-luciferase reporter gene assay confirmed that miR-664a-3p is preferentially bound to BMP2. Furthermore, the effect of the miR-664a-3p/BMP2 axis on osteogenic differentiation in AVICs was examined using the gain- and loss-of-function approach. Finally, we constructed a mouse CAVD model and verified the effect of the miR-664a-3p/BMP2 axis on the aortic valve calcification leaflets in vivo. In conclusion, miR-664a-3p regulates osteogenic differentiation in AVICs through negative regulation of BMP2, highlighting that miR-664a-3p may be a potential therapeutic target for CAVD.

Platelet extracellular vesicles and the secretory interactome join forces in health and disease

Extracellular vesicles (EVs) are small membrane-bound vesicles released by cells under various conditions. They are found in the extracellular milieu in all biological fluids. As the concentrations, contents, and origin of EVs can change during inflammation, the assessment of EVs can be used as a proxy of cellular activation. Here, we review the literature regarding EVs, more particularly those released by platelets and their mother cells, the megakaryocytes. Their cargo includes cytokines, growth factors, organelles (mitochondria and proteasomes), nucleic acids (messenger and non-coding RNA), transcription factors, and autoantigens. EVs may thus contribute to intercellular communication by facilitating exchange of material between cells. EVs also interact with other molecules secreted by cells. In autoimmune diseases, EVs are associated with antibodies secreted by B cells. By definition, EVs necessarily comprise a phospholipid moiety, which is thus the target of secreted phospholipases also abundantly expressed in the extracellular milieu. We discuss how platelet-derived EVs, which represent the majority of the circulating EVs, may contribute to immunity through the activity of their cargo or in combination with the secretory interactome.

Extracellular Vesicles and Hepatocellular Carcinoma: Opportunities and Challenges

The incidence of hepatocellular carcinoma (HCC) is increasing worldwide. Extracellular vesicles (EVs) contain sufficient bioactive substances and are carriers of intercellular information exchange, as well as delivery vehicles for nucleic acids, proteins and drugs. Although EVs show great potential for the treatment of HCC and their role in HCC progression has been extensively studied, there are still many challenges such as time-consuming extraction, difficult storage, easy contamination, and low drug loading rate. We focus on the biogenesis, morphological characteristics, isolation and extraction of EVs and their significance in the progression of HCC, tumor invasion, immune escape and cancer therapy for a review. EVs may be effective biomarkers for molecular diagnosis of HCC and new targets for tumor-targeted therapy.

Hepatocyte-derived exosomal miR-27a activates hepatic stellate cells through the inhibition of PINK1-mediated mitophagy in MAFLD

The role of exosome-mediated mitophagy in the crosstalk between hepatocytes (HCs) and hepatic stellate cells (HSCs) in metabolic-associated fatty liver disease (MAFLD) remains unknown. Serum exosomal miR-27a levels were markedly increased and positively correlated with liver fibrosis in MAFLD patients and mice. Exosomal miR-27a was released from lipotoxic HCs and specifically transmitted to recipient-activated HSCs. PINK1, the key target of miR-27a, primarily mediates mitophagy. Overexpression of miR-27a or knockdown of PINK1 or lipotoxic HC-exosomal miR-27a impaired mitochondria (inhibiting mitophagy, respiration, membrane potential, and transcription while promoting reactive oxygen species production) in activated HSCs and stimulated HSC-derived fibroblasts (promoting activation and proliferation while inhibiting autophagy). High exosomal miR-27a serum levels and a lack of hepatic PINK1-mediated mitophagy were directly related to liver fibrosis in MAFLD mice. Lipotoxic HC exosome transplantation aggravated the degree of PINK1-mediated mitophagy suppression, steatohepatitis, lipidosis, and fibrosis in the livers of MAFLD mice with cirrhosis. Both in vitro and in vivo, exosomes derived from miR-27a-knockdown HCs could not facilitate the abovementioned deteriorating effects. In conclusion, lipotoxic HC-exosomal miR-27a plays a pivotal role in inhibiting mitophagy and in promoting MAFLD-related liver fibrosis by negatively regulating PINK1 expression.

Clinical impact of serum exosomal microRNA in liver fibrosis

BACKGROUND/AIM

We investigated alterations in the expression of serum exosomal miRNAs with the progression of liver fibrosis and evaluated their clinical applicability as biomarkers.

METHODS

This study prospectively enrolled 71 patients who underwent liver biopsy at an academic hospital in Korea. Exosomes were extracted from serum samples, followed by next-generation sequencing (NGS) of miRNAs and targeted real-time quantitative polymerase chain reaction. A model was derived to discriminate advanced fibrosis based on miRNA levels and the performance of this model was evaluated. Validation of the effect of miRNA on liver fibrosis in vitro was followed.

RESULTS

NGS data revealed that exosomal miR-660-5p, miR-125a-5p, and miR-122 expression were changed significantly with the progression of liver fibrosis, of which miR-122 exhibited high read counts enough to be used as a biomarker. The level of exosomal miR-122 decreased as the pathologic fibrosis grade progressed and patients with biopsy-proven advanced fibrosis had significantly lower levels of exosomal miR-122 (P < 0.001) than those without advanced fibrosis. Exosomal miR-122 exhibited a fair performance in discriminating advanced fibrosis especially in combination with fibrosis-4 score and transient elastography. In a subgroup of patients with a non-viral etiology of liver disease, the performance of exosomal miR-122 as a biomarker was greatly improved. Inhibition of miR-122 expression increased the proliferation of the human hepatic stellate cell line, LX-2, and upregulated the expression of various fibrosis related proteins.

CONCLUSION

Exosomal miR-122 may serve as a useful non-invasive biomarker for liver fibrosis, especially in patients with non-viral etiologies of chronic liver disease.

Role of extracellular vesicles in liver diseases and their therapeutic potential

More than eight hundred million people worldwide have chronic liver disease, with two million deaths per year. Recurring liver injury results in fibrogenesis, progressing towards cirrhosis, for which there doesn't exists any cure except liver transplantation. Better understanding of the mechanisms leading to cirrhosis and its complications is needed to develop effective therapies. Extracellular vesicles (EVs) are released by cells and are important for cell-to-cell communication. EVs have been reported to be involved in homeostasis maintenance, as well as in liver diseases. In this review, we present current knowledge on the role of EVs in non-alcoholic fatty liver disease and non-alcoholic steatohepatitis, alcohol-associated liver disease, chronic viral hepatitis, primary liver cancers, acute liver injury and liver regeneration. Moreover, therapeutic strategies involving EVs as targets or as tools to treat liver diseases are summarized.

Hepatocyte-derived exosome may be as a biomarker of liver regeneration and prognostic valuation in patients with acute-on-chronic liver failure

BACKGROUND

The assessment of liver regeneration is particularly critical for patients with acute-on-chronic liver failure (ACLF). Exosome has both the advantages of specificity of liver biopsy and noninvasion of peripheral blood, which may be the potential biomarker of liver disease.

METHODS

The patients with chronic hepatitis B (CHB) and ACLF were enrolled from outpatients and inpatients in Beijing Youan Hospital, Capital Medical University. The exosomes in plasma were extracted by ultracentrifuge using Optima XPN-100 Ultracentrifuge. Exosomes were dyed with fluorescent direct-labeled antibody and the expression profile was assayed using ImageStream® X MKII Imaging Flow Cytometer.

RESULTS

The percentage of exosomes with ALB and CD63 was significant higher in ACLF than that in CHB. The percentage of exosomes with ALB and CD63 and VEGF increased in CHB, but decreased in ACLF. The exosomes with ALB, CD63, and VEGF were significant more in survival group than that in dead group in patients with ACLF. The sensitivity and specificity of exosomes with CD63, ALB, and VEGF were significantly higher than the other markers of liver regeneration and prognostic valuation in patients with ACLF including AFP. The hepatocyte-derived exosomes expression profile had no difference in different stages and different AFP levels of patients with ACLF.

CONCLUSION

The exosomes profile with ALB and VEGF may be a more accurate and specific biomarker of liver regeneration and prognostic valuation than AFP in patients with ACLF. In addition, the exosomes profile with CD63 and ALB may be an early-warning marker in patients with ACLF.

Portal hypertension and hepatocellular carcinoma: Des liaisons dangereuses…

BACKGROUND AND AIMS

Portal hypertension (PHT) and hepatocellular carcinoma (HCC) are major complication of cirrhosis which significantly contribute to morbidity and mortality. In this review, we aim to describe the consequences of both angiogenesis and inflammation in the pathogenesis of PHT and HCC, but also the difficulty to propose adapted treatment when PHT and HCC coexist in the same patients.

METHODS

Studies for review in this article were retrieved from the PubMed database using literature published in English until March 2021.

RESULTS

Portal hypertension occurs secondary to an increase of intrahepatic vascular resistances, the opening of portosystemic collateral vessels and the formation of neovessels, related to vascular endothelial growth factor (VEGF). Recently, bacterial translocation-mediated inflammation was also identified as a major contributor to PHT. Interestingly, VEGF and chronic inflammation also contribute to HCC occurrence. As PHT and HCC often coexist in the same patient, management of PHT and its related complications as well as HCC treatment appear more complex. Indeed, PHT-related complications such as significant ascites may hamper the access to HCC treatment and the presence of HCC is also independently associated with poor prognosis in patients with acute variceal bleeding related to PHT. Due to their respective mechanism of action, the combination of Atezolizumab and Bevacizumab for advanced HCC may impact the level of PHT and its related complications and to date, no real-life data are available.

CONSLUSIONS

Appropriate evaluation and treatment of PHT remains a major issue in order to improve the outcome of HCC patients.

Circulating extracellular vesicles induce monocyte dysfunction and are associated with sepsis and high mortality in cirrhosis

BACKGROUND

Sepsis is common in cirrhosis and is often a result of immune dysregulation. Specific stimuli and pathways of inter-cellular communications between immune cells in cirrhosis and sepsis are incompletely understood. Immune cell-derived extracellular vesicles (EV) were studied to understand mechanisms of sepsis in cirrhosis.

METHODS

Immune cell-derived EV were measured in cirrhosis patients [Child-Turcotte-Pugh (Child) score A, n = 15; B n = 16; C n = 43 and Child-C with sepsis (n = 38)], and healthy controls (HC, n = 11). In vitro and in vivo functional relevance of EV in cirrhosis and associated sepsis was investigated.

RESULTS

Monocyte, neutrophil and hematopoietic stem cells associated EV progressively increased with higher Child score (P < .001)and correlated with liver disease severity indices (r²  > 0.3, P < .001), which further increased in Child C sepsis than without sepsis(P < .001); monocyte EV showing the highest association with disease stage [P = .013; Odds ratio-4.14(1.34-12.42)]. A threshold level of monocyte EV of 53/µl predicted mortality in patients of Child C with sepsis [Odds ratio-6.2 (2.4-15.9), AUROC = 0.76, P < .01]. In vitro EV from cirrhotic with sepsis compared without sepsis, induced mobilization arrest in healthy monocytes within 4 hours (P = .004), reduced basal oxygen consumption rate (P < .001) and induced pro-inflammatory genes (P < .05). The septic-EV on adoptive transfer to C57/BL6J mice, induced sepsis-like condition within 24 h with leukocytopenia (P = .005), intrahepatic inflammation with increased CD11b + cells (P = .03) and bone marrow hyperplasia (P < .01).

CONCLUSION

Extracellular vesicles induce functional impairment in circulating monocytes and contribute to the development and perpetuation of sepsis. High levels of monocyte EV correlate with mortality and can help early stratification of sicker patients.

Circulating extracellular vesicles are a biomarker for NAFLD resolution and response to weight loss surgery

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.

YAP-Dependent Induction of CD47-Enriched Extracellular Vesicles Inhibits Dendritic Cell Activation and Ameliorates Hepatic Ischemia-Reperfusion Injury

Hepatic ischemia-reperfusion injury (IRI) is the most common cause of liver damage leading to surgical failures in hepatectomy and liver transplantation. Extensive inflammatory reactions and oxidative responses are reported to be the major processes exacerbating IRI. The involvement of Yes-associated protein (YAP) in either process has been suggested, but the role and mechanism of YAP in IRI remain unclear. In this study, we constructed hepatocyte-specific YAP knockout (YAP-HKO) mice and induced a hepatic IRI model. Surprisingly, the amount of serum EVs decreased in YAP-HKO compared to WT mice during hepatic IRI. Then, we found that the activation of YAP increased EV secretion through F-actin by increasing membrane formation, while inhibiting the fusion of multivesicular body (MVB) and lysosomes in hepatocytes. Further, to explore the essential elements of YAP-induced EVs, we applied mass spectrometry and noticed CD47 was among the top targets highly expressed on hepatocyte-derived EVs. Thus, we enriched CD47+ EVs by microbeads and applied the isolated CD47+ EVs on IRI mice. We found ameliorated IRI symptoms after CD47+ EV treatment in these mice, and CD47+ EVs bound to CD172α on the surface of dendritic cells (DCs), which inhibited DC activation and the cascade of inflammatory responses. Our data showed that CD47-enriched EVs were released in a YAP-dependent manner by hepatocytes, which could inhibit DC activation and contribute to the amelioration of hepatic IRI. CD47+ EVs could be a potential strategy for treating hepatic IRI.

The diagnostic value of exosomal miRNAs in human bile of malignant biliary obstructions

BACKGROUND

Diagnosis of malignant biliary obstruction is complicated and lacks accuracy. Exosomes may be secreted by malignant tumors; intact miRNAs from exosomes might serve as potential biomarkers for the disease.

AIM

To identify exosomal microRNAs in human bile among benign and malignant biliary obstructions.

METHODS

Bile samples were collected from patients undergoing therapeutic endoscopic retrograde cholangiopancreatography for biliary obstruction. Exosome microRNAs were determined by RNA-sequencing in the discovery cohort, which comprising benign (n = 5) cases and malignant biliary obstruction (n = 5) cases. Then, the diagnostic performance of the two up-regulated microRNAs (mir-483-5p and mir-126-3p) of bile exosomes was verified by analysis of 82 patients with a diagnosis of malignant (n=37) or nonmalignant (n=45) biliary obstruction.

RESULTS

In both cohorts, the expressions of mir-483-5p and mir-126-3p were significantly higher in bile exosomes samples from patients with malignant biliary obstructions than controls. In the verification cohort, the two miRNAs can distinguished the benign and malignant groups with high diagnostic accuracy and specificity; the diagnostic values of the two microRNAs were better than serum carbohydrate antigen 19-9 (CA19-9), area under the curve (AUC) were 0.81 and 0.74.

CONCLUSION

The expression of exosomal mir-483-5p and mir-126-3p in the bile samples discriminates between patients with malignant and nonmalignant biliary obstructions.

CLINICAL TRIAL REGISTRATION NO

NCT03102268.

Von Willebrand and Factor VIII Portosystemic Circulation Gradient in Cirrhosis: Implications for Portal Vein Thrombosis

Portal vein thrombosis seems to be dependent on local hypercoagulation and venous stasis; data regarding endothelial damage are lacking.

Microvesicles - promising tiny players' of cancer stem cells targeted liver cancer treatments: The interesting interactions and therapeutic aspects

Liver cancer is one of the most malignant cancers worldwide with poor prognosis. Intracellular mediators like microvesicles (MVs) and cancer stem cells (CSCs) are considered as potential candidates in liver cancer progression. CSCs receive stimuli from the tumor microenvironment to initiate tumor formation in which it's secreted MVs play a noteworthy role. The phenotypic conversion of tumor cells during epithelial-to-mesenchymal transition (EMT) is a key step in tumor invasion and metastasis which indicates that the diverse cell populations within the primary tumor are in a dynamic balance and can be regulated by cell to cell communication via secreted microvesicles. Thus, in this review, we aim to highlight the evidences that suggest CSCs are crucial for liver cancer development where the microvesicles plays an important part in the maintenance of its stemness properties. In addition, we summarize the existing evidences that support the concept of microvesicles, the tiny particles have a big role behind the rare immortal CSCs which controls the tumor initiation, propagation and metastasis in liver cancer. Identifying interactions between CSCs and microvesicles may offer new insights into precise anti-cancer therapies in the future.

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.

Extracellular vesicles: Potential impact on cardiovascular diseases

Extracellular vesicles (EVs) have received considerable attention in biological and clinical research due to their ability to mediate cell-to-cell communication. Based on their size and secretory origin, EVs are categorized as exosomes, microvesicles, and apoptotic bodies. Increasing number of studies highlight the contribution of EVs in the regulation of a wide range of normal cellular physiological processes, including waste scavenging, cellular stress reduction, intercellular communication, immune regulation, and cellular homeostasis modulation. Altered circulating EV level, expression pattern, or content in plasma of patients with cardiovascular disease (CVD) may serve as diagnostic and prognostic biomarkers in diverse cardiovascular pathologies. Due to their inherent characteristics and physiological functions, EVs, in turn, have become potential candidates as therapeutic agents. In this review, we discuss the evolving understanding of the role of EVs in CVD, summarize the current knowledge of EV-mediated regulatory mechanisms, and highlight potential strategies for the diagnosis and therapy of CVD. We also attempt to look into the future that may advance our understanding of the role of EVs in the pathogenesis of CVD and provide novel insights into the field of translational medicine.

Circulating Extracellular Vesicles Carrying Sphingolipid Cargo for the Diagnosis and Dynamic Risk Profiling of Alcoholic Hepatitis

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 < 0.0001), heavy drinkers (1.28 × 10¹¹ /mL; P < 0.0001), ESLD (5.35 × 10¹⁰ /mL; P < 0.0001), and decompensated AC (9.2 × 10¹⁰ /mL; P < 0.0001) disease controls. Among AH subjects, EV concentration correlated with Model for End-Stage Liver Disease score. When EV counts were dichotomized at the median, survival probability for AH subjects at 90 days was 63.0% in the high-EV group and 90.0% in the low-EV group (log-rank P value = 0.015). Interestingly, EV sphingolipid cargo was significantly enriched in AH when compared to healthy controls, heavy drinkers, ESLD, and decompensated AC (P = 0.0001). Multiple sphingolipids demonstrated good diagnostic and prognostic performance as biomarkers for AH.

CONCLUSIONS

Circulating EV concentration and sphingolipid cargo signature can be used in the diagnosis and differentiation of AH from heavy drinkers, decompensated AC, and other etiologies of ESLD and predict 90-day survival permitting dynamic risk profiling.

Alcohol-and-HIV-Induced Lysosomal Dysfunction Regulates Extracellular Vesicles Secretion in Vitro and in Liver-Humanized Mice

BACKGROUND

Alcohol abuse is common in people living with HIV-1 and dramaticallyenhances the severity of HIV-induced liver damage by inducing oxidative stress and lysosomaldysfunction in the liver cells. We hypothesize that the increased release of extracellular vesicles(EVs) in hepatocytes and liver humanized mouse model is linked to lysosome dysfunction.

METHODS

The study was performed on primary human hepatocytes and human hepatoma RLWXP-GFP (Huh7.5 cells stably transfected with CYP2E1 and XPack-GFP) cells and validated on ethanol-fed liverhumanizedfumarylacetoacetate hydrolase (Fah)-/-, Rag2-/-, common cytokine receptor gamma chainknockout (FRG-KO) mice. Cells and mice were infected with HIV-1ADA virus.

RESULTS

We observedan increase in the secretion of EVs associated with a decrease in lysosomal activity and expressionof lysosomal-associated membrane protein 1. Next-generation RNA sequencing of primary humanhepatocytes revealed 63 differentially expressed genes, with 13 downregulated and 50 upregulatedgenes in the alcohol-HIV-treated group. Upstream regulator analysis of differentially expressedgenes through Ingenuity Pathway Analysis identified transcriptional regulators affecting downstreamgenes associated with increased oxidative stress, lysosomal associated disease, and function andEVs biogenesis. Our in vitro findings were corroborated by in vivo studies on human hepatocytetransplantedhumanized mice, indicating that intensive EVs' generation by human hepatocytes andtheir secretion to serum was associated with increased oxidative stress and reduction in lysosomalactivities triggered by HIV infection and ethanol diet.

CONCLUSION

HIV-and-ethanol-metabolisminducedEVs release is tightly controlled by lysosome status in hepatocytes and participates in thedevelopment of double-insult-induced liver injury.

Efficacy and Safety of Emricasan in Liver Cirrhosis and/or Fibrosis

This study aimed to perform a meta-analysis to determine the efficacy and safety of emricasan. Nine databases were searched for clinical trials investigating the efficacy of emricasan treatment in patients with liver cirrhosis or fibrosis. A manual search was conducted to identify the missing trials. The quality of the included studies was assessed using the revised Cochrane risk of bias tool. Efficacy of emricasan treatment was defined as a positive change in apoptosis-related parameters from baseline to the last follow-up visit. Overall, emricasan treatment is more effective in patients with liver cirrhosis or fibrosis than placebo (standardized mean difference [SMD] [95% confidence intervals (CI)]=0.28 [0.14; 0.41]). No significant change in model for end-stage liver disease (MELD) score between the emricasan and placebo groups was noted (SMD [95% CI]=0.18 [-0.01; 0.36]; p=0.058). A 50 mg dose of emricasan had the highest efficacy rate compared to placebo (SMD [95% CI]=0.28 [0.06; 0.50]; p=0.012), followed by the 5 mg dosing regimen (SMD [95% CI]=0.28 [0.06; 0.50]; p=0.012). Treatment with emricasan resulted in significant reductions in ALT (mean difference (MD) [95% CI]=-5.89 [-10.59; -1.20]; p=0.014) and caspase3/7 levels (MD [95%CI]=-1215.93 [-1238.53; -1193.33]; p<0.001), respectively. No significant increase in the rate of overall adverse events was noted (OR [95% CI]=1.52 [0.97; 2.37]; p=0.069). Treatment with emricasan is more effective in improving liver function and apoptosis parameters compared to placebo, with a well-tolerated safety profile. However, due to the poor quality of the analyzed studies, the small number of trials and patients, and the short follow-up periods, more robust trials are still warranted.

Anticoagulation in patients with advanced liver disease: an open issue

Liver disease has been long considered as a risk factor for bleeding for the presence of prolongation of global tests of clotting activation and low platelet count. For this reason, the use of anticoagulants in patients with liver disease and an indication to anticoagulation, such as atrial fibrillation of venous thrombosis, has been poorly considered. Furthermore, recent studies underscored the fact that patients with chronic liver disease may experience thrombosis in portal as well as systemic circulation and treatment with anticoagulants should be considered. The introduction of direct oral anticoagulants has increased therapeutic options for thromboprophylaxis; however, evidence on their safety and efficacy in specific populations, such as patients with liver disease, is still scarce and needs further investigation. Thus, atrial fibrillation patients with coexistent liver disease have been excluded from clinical trials with direct oral anticoagulants. Here, we provide an overview on mechanisms of thrombosis in patients with advanced chronic liver disease and a summary of evidence on the use of oral anticoagulants in patients with liver disease and portal vein thrombosis or atrial fibrillation.

Extracellular vesicles as biomarkers in liver diseases: A clinician's point of view

Extracellular vesicles are membrane-bound vesicles containing proteins, lipids, RNAs and microRNAs. They can originate from both healthy and stressed cells, and provide a snapshot of the cell of origin in physiological and pathological circumstances. Various processes that may give rise to the release of extracellular vesicles occur in liver diseases, including hepatocyte apoptosis, hepatic stellate cell activation, liver innate immune system activation, systemic inflammation, and organelle dysfunction (mitochondrial dysfunction and endoplasmic reticulum stress). Numerous studies have therefore investigated the potential role of extracellular vesicles as biomarkers in liver diseases. This review provides an overview of the methods that can be used to measure extracellular vesicle concentrations in clinical settings, ranging from plasma preparation to extracellular vesicle measurement techniques, as well as looking at the challenges of using extracellular vesicles as biomarkers. We also provide a comprehensive review of studies that test extracellular vesicles as diagnostic, severity and prognostic biomarkers in various liver diseases, including non-alcoholic and alcoholic steatohepatitis, viral hepatitis B and C infections, cirrhosis, primary liver cancers, primary sclerosing cholangitis and acute liver failure. In particular, extracellular vesicles could be useful tools to evaluate activity and fibrosis in non-alcoholic fatty liver disease, predict risk of hepatitis B virus reactivation, predict complications and mortality in cirrhosis, detect early hepatocellular carcinoma, detect malignant transformation in primary sclerosing cholangitis and predict outcomes in acute liver failure. While most studies draw on data derived from pilot studies, which still require clinical validation, some extracellular vesicle subpopulations have already been evaluated in solid prospective studies.

Circulating microRNAs associated with liver fibrosis in chronic hepatitis C patients

A major challenge in hepatitis C research is the detection of early potential for progressive liver disease. MicroRNAs (miRNAs) are small RNAs that regulate gene expression and can be biomarkers of pathological processes. In this study, we compared circulating miRNAs identified in hepatitis C virus (HCV)-infected patients presenting two extremes of liver disease: mild/moderate fibrosis and cirrhosis. The patients in the cirrhosis group subsequently developed hepatocellular carcinoma (HCC). We identified 163 mature miRNAs in the mild/moderate fibrosis group and 171 in the cirrhosis group, with 144 in common to both groups. Differential expression analysis revealed 5 upregulated miRNAs and 2 downregulated miRNAs in the cirrhosis group relative to the mild/moderate fibrosis group. Functional analyses of regulatory networks (target gene and miRNA) identified gene categories involved in cell cycle biological processes and metabolic pathways related to cell cycle, cancer, and apoptosis. These results suggest that the differentially expressed circulating miRNAs observed in this work (miR-215-5p, miR-483-5p, miR-193b-3p, miR-34a-5p, miR-885-5p, miR-26b-5p and miR -197-3p) may be candidates for biomarkers in the prognosis of liver disease.

The potential diagnostic and therapeutic applications of exosomes in drug-induced liver injury

Drug-induced liver injury (DILI) has gradually become a global public medical problem, which can be caused by more than 1000 currently available drugs. Unfortunately, the diagnosis and treatment of DILI are limited and imperfect. Exosomes can be secreted by a variety of cells and tissues in the body, rich in cell-type specific proteins, nucleic acids and lipids, which has been widely studied as an important intercellular communication vehicle in liver diseases. Emerging data suggest that circulating exosomes and their cargos can be used as minimally-invasive sources of potential molecular biomarkers for the early detection, monitoring and evaluation of DILI. Exosomes in the urine were also found to contain proteins or RNAs that were indicative of DILI. In addition, exosomes derived from mesenchymal stem cell or hepatocyte are considered potential therapeutic agents to promote liver regenerative responses, modulate inflammatory response and deduce hepatocytes apoptosis. Based on the current findings, we suggest the potential applications of exosomes as biomarkers and therapeutics for DILI.

Extracellular vesicles: Roles and applications in drug-induced liver injury

Extracellular vesicles (EV) are defined as nanosized particles, with a lipid bilayer, that are unable to replicate. There has been an exponential increase of research investigating these particles in a wide array of diseases and deleterious states (inflammation, oxidative stress, drug-induced liver injury) in large part due to increasing recognition of the functional capacity of EVs. Cells can package lipids, proteins, miRNAs, DNA, and RNA into EVs and send these discrete packages of molecular information to distant, recipient cells to alter the physiological state of that cell. EVs are innately heterogeneous as a result of the diverse molecular pathways that are used to generate them. However, this innate heterogeneity of EVs is amplified due to the diversity in isolation techniques and lack of standardized nomenclature in the literature making it unclear if one scientist's "exosome" is another scientist's "microvesicle." One goal of this chapter is to provide the contextual understanding of EV origin so one can discern between divergent nomenclature. Further, the chapter will explore the potential protective and harmful roles that EVs play in DILI, and the potential of EVs and their cargo as a biomarker. The use of EVs as a therapeutic as well as a vector for therapeutic delivery will be discussed.

Molecular Mechanisms Underlying the Cardiovascular Toxicity of Specific Uremic Solutes

Mounting evidence strongly suggests a causal link between chronic kidney disease (CKD) and cardiovascular disease (CVD). Compared with non-CKD patients, patients with CKD suffer disproportionately from CVD and derive suboptimal benefits from interventions targeting conventional CVD risk factors. Uremic toxins (UTs), whose plasma levels rapidly rise as CKD progresses, represent a unique risk factor in CKD, which has protean manifestations on CVD. Among the known UTs, tryptophan metabolites and trimethylamine N-oxide are well-established cardiovascular toxins. Their molecular mechanisms of effect warrant special consideration to draw translational value. This review surveys current knowledge on the effects of specific UTs on different pathways and cell functions that influence the integrity of cardiovascular health, with implication for CVD progression. The effect of UTs on cardiovascular health is an example of a paradigm in which a cascade of molecular and metabolic events induced by pathology in one organ in turn induces dysfunction in another organ. Deciphering the molecular mechanisms underlying such cross-organ pathologies will help uncover therapeutic targets to improve the management of CVD in patients with CKD.

A preliminary study: proteomic analysis of exosomes derived from thyroid-stimulating hormone-stimulated HepG2 cells

BACKGROUND

Thyroid-stimulating hormone (TSH) plays an important role in the regulation of lipid metabolism. However, little is known about the role that exosomes play in the process of TSH-induced lipotoxicity in non-alcoholic fatty liver disease (NAFLD). As a preliminary step, the present study set out to investigate alterations in protein expression in exosomes derived from TSH-stimulated HepG2 cells.

METHODS

HepG2 cells were treated with TSH, exosomes were collected, and proteins were identified by mass spectrometry (MS). Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genome (KEGG) pathway analysis were performed to analyze the identified proteins.

RESULTS

TSH treatment significantly increased exosomal production and changed the exosomal proteomic profile in HepG2 cells. Among the 1728 proteins, 140 identified proteins were upregulated and seven proteins were downregulated. GO analysis and KEGG analysis revealed that these proteins were involved in multiple processes including metabolism, apoptosis, and inflammation.

CONCLUSION

Our preliminary study demonstrated that exosomes derived from TSH-stimulated hepatocytes were increased and showed a specific altered spectrum of proteins, many of which were involved in metabolism, signal transduction, apoptosis, and inflammation. This study offers new insights into the pathogenesis of TSH-induced lipotoxicity in NAFLD.

Predicting the risk of portal vein thrombosis in patients with liver cirrhosis and hepatocellular carcinoma

The mechanisms of the hypercoagulable state in cirrhotics with and without hepatocellular carcinoma are incompetently comprehended. Objective: We aimed to explore the plasma Annexin A5/PS + MP ratio in these patients. Higher levels of Annexin A5 and PhosphatidylSerine bearing microparticles have been observed in cases of inflammation and increased coagulation but there are no studies which explore if there is an association between them and PVT in cirrhotics with and without HCC. So, our goal is to estimate their role in predicting PVT within HCV cirrhotics with and without HCC. 91 HCV cirrhotics with and without HCC and 20 healthy people (controls) were enlisted. Cirrhotics with and without HCC who developed PVT displayed higher levels of PS + MPs and lower Annexin A5/PS + MPs ratio (38.73 ± 1.92) and (0.00238 ± 0.00047) than cirrhotics who didn't develop PVT (22.19 ± 10.58) and (0.00451 ± 0.0023) (P < 0.001). Among the tested factors, lower Annexin A5/PS + MPs ratio show higher performance in predicting PVT in total cirrhotics, AUC, 0.919 followed by PS + MPs level, 0.876, Portal flow velocity, 0.842, Plasma Annexin A5 level, 0.509. In our hypothesis, As phosphatidylserine exposure increase due to increased level of circulating microparticles in cirrhotics with and without HCC, anenxin-A5 may be secreted by platelets and endothelial cells into the circulation as a physiological response to inactivate the elevated levels of PS bearing MPs produced in these patients but the increase in anenxin-A5 level isn't equivalent to the increase in PS bearing MPs levels. The equilibrium between plasma annexin A5 and PS bearing MPs levels is defected.

Ectosomal PKM2 Promotes HCC by Inducing Macrophage Differentiation and Remodeling the Tumor Microenvironment

Tumor-derived extracellular vesicles are important mediators of cell-to-cell communication during tumorigenesis. Here, we demonstrated that hepatocellular carcinoma (HCC)-derived ectosomes remodel the tumor microenvironment to facilitate HCC progression in an ectosomal PKM2-dependent manner. HCC-derived ectosomal PKM2 induced not only metabolic reprogramming in monocytes but also STAT3 phosphorylation in the nucleus to upregulate differentiation-associated transcription factors, leading to monocyte-to-macrophage differentiation and tumor microenvironment remodeling. In HCC cells, sumoylation of PKM2 induced its plasma membrane targeting and subsequent ectosomal excretion via interactions with ARRDC1. The PKM2-ARRDC1 association in HCC was reinforced by macrophage-secreted cytokines/chemokines in a CCL1-CCR8 axis-dependent manner, further facilitating PKM2 excretion from HCC cells to form a feedforward regulatory loop for tumorigenesis. In the clinic, ectosomal PKM2 was clearly detected in the plasma of HCC patients. This study highlights a mechanism by which ectosomal PKM2 remodels the tumor microenvironment and reveals ectosomal PKM2 as a potential diagnostic marker for HCC.

Liver fibrogenesis: un update on established and emerging basic concepts

Liver fibrogenesis is defined as a dynamic and highly integrated process occurring during chronic injury to liver parenchyma that can result in excess deposition of extracellular matrix (ECM) components (i.e., liver fibrosis). Liver fibrogenesis, together with chronic inflammatory response, is then primarily involved in the progression of chronic liver diseases (CLD) irrespective of the specific etiology. In the present review we will first offer a synthetic and updated overview of major basic concepts in relation to the role of myofibroblasts (MFs), macrophages and other hepatic cell populations involved in CLD to then offer an overview of established and emerging issues and mechanisms that have been proposed to favor and/or promote CLD progression. A special focus will be dedicated to selected issues that include emerging features in the field of cholangiopathies, the emerging role of genetic and epigenetic factors as well as of hypoxia, hypoxia-inducible factors (HIFs) and related mediators.

Extracellular Vesicles in NAFLD/ALD: From Pathobiology to Therapy

In recent years, knowledge on the biology and pathobiology of extracellular vesicles (EVs) has exploded. EVs are submicron membrane-bound structures secreted from different cell types containing a wide variety of bioactive molecules (e.g., proteins, lipids, and nucleic acids (coding and non-coding RNA) and mitochondrial DNA). EVs have important functions in cell-to-cell communication and are found in a wide variety of tissues and body fluids. Better delineation of EV structures and advances in the isolation and characterization of their cargo have allowed the diagnostic and therapeutic implications of these particles to be explored. In the field of liver diseases, EVs are emerging as key players in the pathogenesis of both nonalcoholic liver disease (NAFLD) and alcoholic liver disease (ALD), the most prevalent liver diseases worldwide, and their complications, including development of hepatocellular carcinoma. In these diseases, stressed/damaged hepatocytes release large quantities of EVs that contribute to the occurrence of inflammation, fibrogenesis, and angiogenesis, which are key pathobiological processes in liver disease progression. Moreover, the specific molecular signatures of released EVs in biofluids have allowed EVs to be considered as promising candidates to serve as disease biomarkers. Additionally, different experimental studies have shown that EVs may have potential for therapeutic use as a liver-specific delivery method of different agents, taking advantage of their hepatocellular uptake through interactions with specific receptors. In this review, we focused on the most recent findings concerning the role of EVs as new structures mediating autocrine and paracrine intercellular communication in both ALD and NAFLD, as well as their potential use as biomarkers of disease severity and progression. Emerging therapeutic applications of EVs in these liver diseases were also examined, along with the potential for successful transition from bench to clinic.