Dabigatran Reduces Liver Fibrosis in Thioacetamide-Injured Rats

Dapagliflozin alleviates thioacetamide induced-liver fibrosis in rats via controlling the Nrf2/HO-1 and TLR4/TGF-β1/PI3K signaling pathways

OBJECTIVES

Because liver fibrosis causes several insults that can result in death, it is regarded as an epidemic health issue. As "an inhibitor of the sodium-glucose cotransporter-2 (SGLT2)," Dapagliflozin (Dapa) is one of the newest anti-diabetic drugs used to treat type 2 diabetes mellitus. Dapa's antioxidant, anti-inflammatory, and antifibrotic properties produced positive impacts in numerous human and animal models. Due to Dapa's previously documented properties, we planned this investigation to elucidate the protective function of Dapa in male rat liver fibrosis caused by thioacetamide (TAA) as well as the expected pathways.

METHODS

There were four groups of 24 rats: a control group, a TAA group that received (100 mg/kg b.wt intraperitoneally twice a week for 6 weeks), "TAA + Dapa" groups that given oral Dapa at (1 and 2 mg/kg b.wt. for 4 weeks in addition to TAA injections).

RESULTS

It was shown that TAA injections increased toll-like receptor 4 (TLR4) (509.6%), tumor necrosis factor (TNF-α) (298.8%), alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), interleukin-6 (IL-6) (330.9%), phosphotidylinositol-3-kinase (PI3K) (428.9% %), and transforming growth factor-beta (TGF-β1) (416.6%) levels. All of these markers were considerably reduced by Dapa treatment. In addition, reduced glutathione (GSH), nuclear factor erythroid 2-related factor 2 (Nrf2) (79%), albumin, Heme-oxygenase 1 (HO-1) (69%), and superoxide dismutase (SOD) were all decreased after TAA injection; however, they were restored by Dapa administration. The Dapa-treated groups had higher Nrf2 and HO-1 gene expressions, based on the results of PCR. Biochemical outcomes were validated by histopathological results. Immunohistopathological study revealed that DAPA treatment decreased caspase-3 and alpha-smooth Muscle Actin (αSMA) expression.

CONCLUSION

Due to its interactions with the Nrf2/HO-1 and TLR4 pathways, our research showed that Dapa had antioxidant and anti-inflammatory qualities against TAA-induced liver fibrosis.

Advancements of direct oral anticoagulants in cirrhotic individuals with portal vein thrombosis

Individuals with cirrhosis maintain a delicate balance between pro- and anticoagulation, which can lead to a state of hypercoagulability. This hypercoagulable condition not only exacerbates liver fibrosis but also increases the risk of venous thrombosis, particularly portal vein thrombosis (PVT). PVT has detrimental effects on liver function, complicates the success of liver transplantation, and negatively impacts the survival rate of patients with cirrhosis. Currently, multiple studies have confirmed that individuals with cirrhosis responded well to treatment with novel direct oral anticoagulants (DOACs), showing both safety and efficacy. Furthermore, the use of DOACs as a preventive measure in patients with cirrhosis following surgery has been shown to lower the occurrence of portal vein thrombosis and postpone the progression of liver fibrosis.

Angiogenesis and Microvascular Permeability

Angiogenesis, the formation of new blood microvessels, is a necessary physiological process for tissue generation and repair. Sufficient blood supply to the tissue is dependent on microvascular density, while the material exchange between the circulating blood and the surrounding tissue is controlled by microvascular permeability. We thus begin this article by reviewing the key signaling factors, particularly vascular endothelial growth factor (VEGF), which regulates both angiogenesis and microvascular permeability. We then review the role of angiogenesis in tissue growth (bone regeneration) and wound healing. Finally, we review angiogenesis as a pathological process in tumorigenesis, intraplaque hemorrhage, cerebral microhemorrhage, pulmonary fibrosis, and hepatic fibrosis. Since the glycocalyx is important for both angiogenesis and microvascular permeability, we highlight the role of the glycocalyx in regulating the interaction between tumor cells and endothelial cells (ECs) and VEGF-containing exosome release and uptake by tumor-associated ECs, all of which contribute to tumorigenesis and metastasis.

Histologic evidence of neutrophil extracellular traps and fibrin(ogen) deposition in liver biopsies from patients with inflammatory liver disease

Background

Liver disease is often characterized by the activation of coagulation and inflammation. Experimental studies suggest that the interaction between neutrophils and platelets with local activation of coagulation could contribute to liver injury progression, but there have been limited studies in humans.

Objectives

We studied the hemostatic components and neutrophil extracellular traps (NETs) in liver biopsies from patients with different inflammatory liver diseases.

Methods

Liver biopsies from patients with inflammatory liver disease (alcoholic steatohepatitis [ASH], autoimmune hepatitis, primary sclerosing cholangitis, metabolic-associated steatohepatitis, and allograft ischemia-reperfusion injury (IRI), each n = 20) were stained for fibrin(ogen), platelets, and NETs. The correlation of NET formation with deposition of hemostatic components and laboratory measures of disease severity was investigated.

Results

In 75% of the liver biopsies, no fibrin(ogen) was detectable, and only 20% of the biopsies showed minimal deposition. Overall, 50% of liver biopsies stained positive for NETs. Platelet deposition and NET formation were highest in IRI, where it correlated with histologic severity of injury (r = .61 [95% CI, .22-.84]; P < .01) and ASH. Platelet deposition was associated with NET formation (r = .44 [95% CI, .27-.59]; P < .001) and colocalized in the biopsies. NET formation, but not fibrin and platelet deposition, was moderately associated with the model of end-stage liver disease score (r = .29 [95% CI, .07-.49]; P < .01).

Conclusion

In contrast to experimental studies, we demonstrated minimal intrahepatic fibrin(ogen) deposition in different types of human inflammatory liver disease. Histologic evidence for intrahepatic NETs was common and most pronounced in acute ASH and IRI and was associated with platelet deposition and disease severity.

Identifying prothrombin and bone sialoprotein as potential drug targets for idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic Pulmonary Fibrosis (IPF) is a fatal disease with scarce therapeutic alternatives, which imposes a significant economic burden on society. The identification of novel drug targets is thus critically essential. Plasma proteins with discernible causal evidence hold promise as viable drug targets for this condition.

METHODS

We performed a proteome-wide Mendelian randomization (MR) analysis to assess the causal effects of 4,907 circulating proteins from the deCODE study on the risk of IPF from the Finngen Database (2,018 cases vs. 373,064 controls). We further replicated the MR analysis in 1426 proteins from the ARIC study and IPF from the UK Biobank (1,369 cases vs. 435,866 controls). Then a series of analyses including Bayesian colocalization, Steiger filtering, and phenotype scanning were conducted to validate the credibility of the MR results. Subsequently, protein-protein interaction (PPI) analysis, pathway enrichment analysis, and druggability assessment were executed to elucidate the underlying mechanisms. Finally, the findings were corroborated using a bleomycin-induced pulmonary fibrosis mouse model.

RESULTS

The MR analysis bolstered by robust evidence of colocalization, indicated a significant positive association between Prothrombin and increased IPF risk (OR = 3.26,95%CI 1.75-6.07). Conversely, Bone Sialoprotein (IBSP) demonstrated an inverse association with IPF susceptibility (OR = 0.27,95%CI 0.14-0.55).

CONCLUSIONS

The integrative analysis suggests that Prothrombin and IBSP are promising candidates as potential drug targets for IPF. Additional clinical investigations are warranted to substantiate these findings.

Molecular Mechanisms Underlying Vascular Liver Diseases: Focus on Thrombosis

Vascular liver disorders (VLDs) comprise a wide spectrum of clinical-pathological entities that primarily affect the hepatic vascular system of both cirrhotic and non-cirrhotic patients. VLDs more frequently involve the portal and the hepatic veins, as well as liver sinusoids, resulting in an imbalance of liver homeostasis with serious consequences, such as the development of portal hypertension and liver fibrosis. Surprisingly, many VLDs are characterized by a prothrombotic phenotype. The molecular mechanisms that cause thrombosis in VLD are only partially explained by the alteration in the Virchow's triad (hypercoagulability, blood stasis, and endothelial damage) and nowadays their pathogenesis is incompletely described and understood. Studies about this topic have been hampered by the low incidence of VLDs in the general population and by the absence of suitable animal models. Recently, the role of coagulation imbalance in liver disease has been postulated as one of the main mechanisms linked to fibrogenesis, so a novel interest in vascular alterations of the liver has been renewed. This review provides a detailed analysis of the current knowledge of molecular mechanisms of VLD. We also focus on the promising role of anticoagulation as a strategy to prevent liver complications and to improve the outcome of these patients.

METTL14 reverses liver fibrosis by inhibiting NOVA2 through an m6A-YTHDF2-dependent mechanism

BACKGROUND

N6-methyladenosine (m6A), the most prevalent internal RNA modification in eukaryotic cells, is dynamically regulated in response to a wide range of physiological and pathological states. Nonetheless, the involvement of METTL14-induced m6A in liver fibrosis (LF) has yet to be established.

METHODS

In vitro, HSC cell lines with knock-down and overexpression of METTL14 were constructed, and the effects of METTL14 gene on the phenotypic function of activated HSCs were observed. The proliferation rate was measured by CCK8 and EDU, the cell proliferation cycle was measured by flow detector, the migration rate was measured by Transwell, and the contractility of F-actin was observed after phalloidin staining. The downstream target gene NOVA2 of METTL14 was screened by combined sequencing of MeRIP-seq and RNA-seq, combined with signal analysis. Adeno-associated virus (AAV) was injected into the tail vein in vivo to knock down the expression of METTL14, so as to further observe the role of METTL14 in the progress of LF.

RESULTS

our research showed that the methylase METTL14 content was decreased in hepatic tissue from patients with LF, leading to a lowered degree of m6A modification. Functionally, we discovered that knocking down m6A methyltransferase METTL14 led to increased HSC activation and a substantial worsening of LF. Mechanically, as shown in a multiomics study of HSCs, depleting METTL14 levels decreased m6A deposition onNOVA2 mRNA transcripts, which prompted the activation of YTHDF2 to detect and degrade the decrease of NOVA2 mRNA.

CONCLUSIONS

METTL14 functioned as a profibrotic gene by suppressing NOVA2 activity in a mechanism dependent on m6A-YTHDF2. Moreover, knocking down METTL14 exacerbated LF, while NOVA2 prevented its development and partly reversed the damage.

Microvascular Thrombosis and Liver Fibrosis Progression: Mechanisms and Clinical Applications

Fibrosis is an unavoidable consequence of chronic inflammation. Extracellular matrix deposition by fibroblasts, stimulated by multiple pathways, is the first step in the onset of chronic liver disease, and its propagation promotes liver dysfunction. At the same time, chronic liver disease is characterized by alterations in primary and secondary hemostasis but unlike previously thought, these changes are not associated with an increased risk of bleeding complications. In recent years, the role of coagulation imbalance has been postulated as one of the main mechanisms promoting hepatic fibrogenesis. In this review, we aim to investigate the function of microvascular thrombosis in the progression of liver disease and highlight the molecular and cellular networks linking hemostasis to fibrosis in this context. We analyze the predictive and prognostic role of coagulation products as biomarkers of liver decompensation (ascites, variceal hemorrhage, and hepatic encephalopathy) and liver-related mortality. Finally, we evaluate the current evidence on the application of antiplatelet and anticoagulant therapies for prophylaxis of hepatic decompensation or prevention of the progression of liver fibrosis.

The plasma degradome reflects later development of NASH fibrosis after liver transplant

Although liver transplantation (LT) is an effective therapy for cirrhosis, the risk of post-LT NASH is alarmingly high and is associated with accelerated progression to fibrosis/cirrhosis, cardiovascular disease and decreased survival. Lack of risk stratification strategies hampers early intervention against development of post-LT NASH fibrosis. The liver undergoes significant remodeling during inflammatory injury. During such remodeling, degraded peptide fragments (i.e., 'degradome') of the ECM and other proteins increase in plasma, making it a useful diagnostic/prognostic tool in chronic liver disease. To investigate whether liver injury caused by post-LT NASH would yield a unique degradome profile that is predictive of severe post-LT NASH fibrosis, a retrospective analysis of 22 biobanked samples from the Starzl Transplantation Institute (12 with post-LT NASH after 5 years and 10 without) was performed. Total plasma peptides were isolated and analyzed by 1D-LC-MS/MS analysis using a Proxeon EASY-nLC 1000 UHPLC and nanoelectrospray ionization into an Orbitrap Elite mass spectrometer. Qualitative and quantitative peptide features data were developed from MSn datasets using PEAKS Studio X (v10). LC-MS/MS yielded ~ 2700 identifiable peptide features based on the results from Peaks Studio analysis. Several peptides were significantly altered in patients that later developed fibrosis and heatmap analysis of the top 25 most significantly changed peptides, most of which were ECM-derived, clustered the 2 patient groups well. Supervised modeling of the dataset indicated that a fraction of the total peptide signal (~ 15%) could explain the differences between the groups, indicating a strong potential for representative biomarker selection. A similar degradome profile was observed when the plasma degradome patterns were compared being obesity sensitive (C57Bl6/J) and insensitive (AJ) mouse strains. The plasma degradome profile of post-LT patients yielded stark difference based on later development of post-LT NASH fibrosis. This approach could yield new "fingerprints" that can serve as minimally-invasive biomarkers of negative outcomes post-LT.

The plasma degradome reflects later development of NASH fibrosis after liver transplant

Although liver transplantation (LT) is an effective therapy for cirrhosis, the risk of post-LT NASH is alarmingly high and is associated with accelerated progression to fibrosis/cirrhosis, cardiovascular disease, and decreased survival. Lack of risk stratification strategies hamper liver undergoes significant remodeling during inflammatory injury. During such remodeling, degraded peptide fragments (i.e., 'degradome') of the ECM and other proteins increase in plasma, making it a useful diagnostic/prognostic tool in chronic liver disease. To investigate whether inflammatory liver injury caused by post-LT NASH would yield a unique degradome profile, predictive of severe post-LT NASH fibrosis, we performed a retrospective analysis of 22 biobanked samples from the Starzl Transplantation Institute (12 with post-LT NASH after 5 years and 10 without). Total plasma peptides were isolated and analyzed by 1D-LC-MS/MS analysis using a Proxeon EASY-nLC 1000 UHPLC and nanoelectrospray ionization into an Orbitrap Elite mass spectrometer. Qualitative and quantitative peptide features data were developed from MSn datasets using PEAKS Studio X (v10). LC-MS/MS yielded ∼2700 identifiable peptide features based on the results from Peaks Studio analysis. Several peptides were significantly altered in patients that later developed fibrosis and heatmap analysis of the top 25 most significantly-changed peptides, most of which were ECM-derived, clustered the 2 patient groups well. Supervised modeling of the dataset indicated that a fraction of the total peptide signal (∼15%) could explain the differences between the groups, indicating a strong potential for representative biomarker selection. A similar degradome profile was observed when the plasma degradome patterns were compared being obesity sensitive (C57Bl6/J) and insensitive (AJ) mouse strains. Both The plasma degradome profile of post-LT patients yields stark difference based on later development of post-LT NASH fibrosis. This approach could yield new "fingerprints" that can serve as minimally-invasive biomarkers of negative outcomes post-LT.

Fibrosis resolution in the mouse liver: Role of Mmp12 and potential role of calpain 1/2

Although most work has focused on resolution of collagen ECM, fibrosis resolution involves changes to several ECM proteins. The purpose of the current study was twofold: 1) to examine the role of MMP12 and elastin; and 2) to investigate the changes in degraded proteins in plasma (i.e., the "degradome") in a preclinical model of fibrosis resolution. Fibrosis was induced by 4 weeks carbon tetrachloride (CCl4) exposure, and recovery was monitored for an additional 4 weeks. Some mice were treated with daily MMP12 inhibitor (MMP408) during the resolution phase. Liver injury and fibrosis was monitored by clinical chemistry, histology and gene expression. The release of degraded ECM peptides in the plasma was analyzed using by 1D-LC-MS/MS, coupled with PEAKS Studio (v10) peptide identification. Hepatic fibrosis and liver injury rapidly resolved in this mouse model. However, some collagen fibrils were still present 28d after cessation of CCl4. Despite this persistent collagen presence, expression of canonical markers of fibrosis were also normalized. The inhibition of MMP12 dramatically delayed fibrosis resolution under these conditions. LC-MS/MS analysis identified that several proteins were being degraded even at late stages of fibrosis resolution. Calpains 1/2 were identified as potential new proteases involved in fibrosis resolution. CONCLUSION. The results of this study indicate that remodeling of the liver during recovery from fibrosis is a complex and highly coordinated process that extends well beyond the degradation of the collagenous scar. These results also indicate that analysis of the plasma degradome may yield new insight into the mechanisms of fibrosis recovery, and by extension, new "theragnostic" targets. Lastly, a novel potential role for calpain activation in the degradation and turnover of proteins was identified.

Emerging Therapeutic Targets for Portal Hypertension

Purpose of Review

Portal hypertension is responsible of the main complications of cirrhosis, which carries a high mortality. Recent treatments have improved prognosis, but this is still far from ideal. This paper reviews new potential therapeutic targets unveiled by advances of key pathophysiologic processes.

Recent Findings

Recent research highlighted the importance of suppressing etiologic factors and a safe lifestyle and outlined new mechanisms modulating portal pressure. These include intrahepatic abnormalities linked to inflammation, fibrogenesis, vascular occlusion, parenchymal extinction, and angiogenesis; impaired regeneration; increased hepatic vascular tone due to sinusoidal endothelial dysfunction with insufficient NO availability; and paracrine liver cell crosstalk. Moreover, pathways such as the gut-liver axis modulate splanchnic vasodilatation and systemic inflammation, exacerbate liver fibrosis, and are being targeted by therapy. We have summarized studies of new agents addressing these targets.

Summary

New agents, alone or in combination, allow acting in complementary mechanisms offering a more profound effect on portal hypertension while simultaneously limiting disease progression and favoring regression of fibrosis and of cirrhosis. Major changes in treatment paradigms are anticipated.

An update on animal models of liver fibrosis

The development of liver fibrosis primarily determines quality of life as well as prognosis. Animal models are often used to model and understand the underlying mechanisms of human disease. Although organoids can be used to simulate organ development and disease, the technology still faces significant challenges. Therefore animal models are still irreplaceable at this stage. Currently, in vivo models of liver fibrosis can be classified into five categories based on etiology: chemical, dietary, surgical, transgenic, and immune. There is a wide variety of animal models of liver fibrosis with varying efficacy, which have different implications for proper understanding of the disease and effective screening of therapeutic agents. There is no high-quality literature recommending the most appropriate animal models. In this paper, we will describe the progress of commonly used animal models of liver fibrosis in terms of their development mechanisms, applications, advantages and disadvantages, and recommend appropriate animal models for different research purposes.

Safety of direct oral anticoagulants in patients with liver disease: a systematic review and meta-analysis

BACKGROUND

Direct oral anticoagulants (DOACs), such as apixaban, edoxaban, rivaroxaban, or dabigatran, are an effective treatment for atrial fibrillation (AF) and deep venous thromboembolism. We hope to evaluate the safety of DOACs versus warfarin/low molecular weight heparin (LMWH) in improving bleeding events in patients with different severity of the liver disease.

METHODS

We systematically searched the Cochrane Library, PubMed, and Embase databases for studies reporting the effects of DOACs in patients with liver cirrhosis. A random-effects model or fixed-effects model was selected to pool risk ratios (RR) and 95% confidence intervals (CI).

RESULTS

A total of 18 studies involving 41,447 participants was included in this meta-analysis. Compare with warfarin/ LMWH, the use of DOACs significantly reduced the incidence of all bleeding (RR: 0.76; 95%CI: 0.66 to 0.87), major bleeding (RR: 0.51; 95%CI: 0.28 to 0.91), intracranial hemorrhage (RR: 0.50; 95%CI: 0.31 to 0.81), and gastrointestinal bleeding (RR: 0.76, 95% CI: 0.60 to 0.97), and all-cause death in patients with liver disease (RR: 0.77; 95%CI: 0.62 to 0.95). Similar results were observed in atrial fibrillation patients with liver disease and cirrhosis subgroups. Furthermore, the pooled estimates of the Child-Turcotte-Pugh (CTP) class indicated that DOACs reduced the incidence of all bleeding (RR: 0.61; 95%CI: 0.45 to 0.82), gastrointestinal bleeding (RR 0.55; 95%CI: 0.37 to 0.83), and all-cause death (RR: 0.62; 95%CI: 0.49 to 0.79) in patients with mild to moderate cirrhosis.

CONCLUSIONS

Our study demonstrates that DOACs significantly reduce the risk of bleeding in patients with liver disease compared with warfarin/LMWH.

Investigational drugs in early clinical development for portal hypertension

INTRODUCTION

Advanced chronic liver disease is considered a reversible condition after removal of the primary aetiological factor. This has led to a paradigm shift in which portal hypertension (PH) is a reversible complication of cirrhosis. The pharmacologic management of PH is centered on finding targets to modify the natural history of cirrhosis and PH.

AREAS COVERED

This paper offers an overview of the use of pharmacological strategies in early clinical development that modify PH. Papers included were selected from searching clinical trials sites and PubMed from the last 10 years.

EXPERT OPINION

A paradigm shift has generated a new concept of PH in cirrhosis as a reversible complication of a potentially curable disease. Decreasing portal pressure to prevent decompensation and further complications of cirrhosis that may lead liver transplantation or death is a goal. Therapeutic strategies also aspire achieve total or partial regression of fibrosis thus eliminating the need for treatment or screening of PH.

Effects of Apixaban, Rivaroxaban, Dabigatran and Enoxaparin on Histopathology and Laboratory Parameters in Achilles Tendon Injury: An in vivo Study

Objectives

To compare the effects of apixaban, rivaroxaban, dabigatran and enoxaparin on histopathology and blood parameters in rats with Achilles tendon injury.

Materials and Methods

Thirty adult, male Wistar albino rats weighting 220-240 g were randomly divided into five (one control and four treatment) groups and placed in a controlled environment. The Achilles tendon was incised and re-sutured in each rat, after which each group was provided the following treatment for 28 days: a) 2 ml saline to the control group, b) apixaban in 1 ml of saline (10 mg/kg/day) +1 ml of saline, c) rivaroxaban in 1 ml of saline (2 mg/kg/day) +1 ml saline, d) dabigatran in 1 ml of saline (30 mg/kg/day) +1 ml of saline, e) enoxaparin (80 μg/kg/day) + 2 ml of saline.

Results

Hemogram, biochemical and coagulation parameters differed significantly between the control and treatment groups (P < 0.05). Compared with the control group, in the apixaban group, type I and type III collagen immunoreactivity were severe and moderate, respectively. In the rivaroxaban and dabigatran groups, both type I and type III collagen immunoreactivity were medium and severe, respectively. In the enoxaparin group, type I and type III collagen immunoreactivity were mild and severe, respectively.

Conclusion

The higher concentration of type I collagen in the apixaban and dabigatran indicates faster tendon healing in these groups, and the higher concentration of the type III collagen in the enoxaparin group indicates slower healing in this group.

Alpinetin exerts anti-inflammatory, anti-oxidative and anti-angiogenic effects through activating the Nrf2 pathway and inhibiting NLRP3 pathway in carbon tetrachloride-induced liver fibrosis

Alpinetin is the major active ingredient of Alpiniakatsumadai Hayata. As a kind of novel plant-derived flavonoid, alpinetin has shown potent hepatoprotective effect against many liver diseases such as non-alcoholic fatty liver and lipopolysaccharide/d-Galactosamine-induced liver injury. However, its roles in liver fibrosis remain to be determined. The aim of the current study was to investigate the effect of alpinetin in mice with carbon tetrachloride (CCl4)-induced liver fibrosis, and to elucidate the underlying mechanisms of action. Alpinetin ameliorated the CCl4-induced liver injury and fibrosis in mice, as shown by decreased collagen deposition and the decreased expression of liver fibrosis marker proteins. Alpinetin suppressed the inflammation and oxidative stress in fibrotic livers of mice, as evidenced by decreased levels of proinflammatory factors, the decreased reactive oxygen species (ROS) and malondialdehyde (MDA) levels, and the increased activities of antioxidant enzymes. In addition, alpinetin attenuated the angiogenesis in fibrotic livers of the test animals. Mechanistically, alpinetin inhibited the CCl4-induced expression of NLRP3, ASC, cleaved caspase-1, mature (cleaved-) IL-1β, and IL-18 in livers of mice. Furthermore, alpinetin resulted in an increased in the nuclear expression and a decrease in the cytoplasmic expression of Nrf2, as well as increased protein expression of downstream target enzymes, GCLC, HO-1, NQO1, and GCLM, thus exerting the antioxidant effect. Overall, these findings suggested that the anti-fibrotic effect of alpinetin can be attributed to the inhibition of NLRP3-mediated anti-inflammatory activities and Nrf2-mediated anti-oxidative activities, in addition to the decrement of hepatic angiogenesis.

Targeting von Willebrand factor in liver diseases: A novel therapeutic strategy?

Acute and chronic liver disease are associated with substantial alterations in the hemostatic system. Evidence from both experimental and clinical studies suggests that anticoagulants slow the progression of liver disease. Efficacy of those anticoagulant drugs is, in part, attributed to a reduction of microthrombi formation within the liver. Although anticoagulant drugs show promising results, bleeding risk associated with these drugs is an obvious drawback, particularly in patients with a complex coagulopathy driven by decreased liver function. Identifying therapies that reduce intrahepatic thrombosis with minimal bleeding risk would significantly advance the field. Among the hemostatic alterations observed in patients are substantially increased levels of the platelet-adhesive protein von Willebrand factor (VWF). In contrast, levels of A Disintegrin and Metalloproteinase with Thrombospondin motifs, the enzyme that regulates VWF activity, are significantly reduced in patients with liver disease. Highly elevated VWF levels are proposed to accelerate intrahepatic thrombus formation and thus be a driver of disease progression. Strong clinical evidence suggesting a link between liver disease and changes in VWF is now being matched by emerging mechanistic data showing a detrimental role for VWF in the progression of liver disease. This review focuses on clinical and experimental evidence supporting a connection between VWF function and the progression of acute and chronic liver diseases. Furthermore, with the recent anticipated approval of several novel therapies targeting VWF, we discuss potential strategies and benefits of targeting VWF as an innovative therapy for patients with liver disease.

Protective effects of paclitaxel on thioacetamide-induced liver fibrosis in a rat model

Liver fibrosis is a public health burden that is highly associated with morbidity and mortality. Therefore, this study aims to explore the anti-fibrotic effects of low dose of paclitaxel (PTX) against thioacetamide (TAA)-induced liver fibrosis in rats and the possible mechanisms involved. TAA was administered at a dose of 200 mg/kg twice weekly for 6 weeks in rats to induce liver fibrosis similar to that in humans. Liver dysfunction was shown by increased alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, and γ-glutamyl transferase, along with histopathological changes. Liver fibrosis was confirmed by Masson's Trichome staining, increased collagen content, and elevated α-smooth muscle actin (α-SMA) protein expression. In addition, TAA induced liver apoptosis as indicated by the increased terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-positive cells in liver tissues. This study demonstrated that the administration of PTX (0.3 mg/kg/i.p.) three times a week for 6 weeks significantly alleviated functional and biochemical changes induced by TAA in addition to improving the liver architecture. PTX attenuated liver fibrosis as reflected by the decreased collagen content and α-SMA protein expression. Additionally, PTX attenuated liver apoptosis as indicated by the decreased TUNEL-positive cells. Moreover, PTX prevented TAA-induced elevation of transforming growth factor-β1 (TGF-β1), platelet-derived growth factor-BB (PDGF-BB), and tissue inhibitor of metalloproteinase 1 (TIMP-1) levels in liver tissues. These findings suggest that the low dose of PTX prevented TAA-induced liver fibrosis in rats, possibly by inhibiting the expression of TGF-β1 and PDGF-BB and subsequently suppressing the apoptosis and the expression of TIMP-1.

The Impact of Dabigatran Treatment on Sinusoidal Protection Against Hepatic Ischemia/Reperfusion Injury in Mice

Thrombin is a key player in the coagulation cascade, and it is attracting much attention as a promotor of cellular injured signaling. In ischemia/reperfusion injury (IRI), which is a severe complication of liver transplantation, thrombin may also promote tissue damage. The aim of this study is to reveal whether dabigatran, a direct thrombin inhibitor, can attenuate hepatic IRI with focusing on a protection of sinusoidal endothelial cells (SECs). Both clinical patients who underwent hepatectomy and in vivo mice model of 60-minute hepatic partial-warm IRII, thrombin generation was evaluated before and after IRI. In next study, IRI mice were treated with or without dabigatran. In addition, hepatic SECs and hepatocytes pretreated with or without dabigatran were incubated in hypoxia/reoxygenation (H-R) environment in vitro. Thrombin generation evaluated by thrombin-antithrombin complex (TAT) was significantly enhanced after IRI in the clinical study and in vivo study. Thrombin exacerbated lactate dehydrogenase cytotoxicity levels in a dose-dependent manner in vitro. In an IRI model of mice, dabigatran treatment significantly improved liver histological damage, induced sinusoidal protection, and provided both antiapoptotic and anti-inflammatory effects. Furthermore, dabigatran not only enhanced endogenous thrombomodulin (TM) but also reduced excessive serum high-mobility group box-1 (HMGB-1). In H-R models of SECs, not hepatocytes, pretreatment with dabigatran markedly attenuated H-R damage, enhanced TM expression in cell lysate, and decreased extracellular HMGB-1. The supernatant of SECs pretreated with dabigatran protected hepatocytes from H-R damage and cellular death. Thrombin exacerbated hepatic IRI, and excessive extracellular HMGB-1 caused severe inflammation-induced and apoptosis-induced liver damage. In this situation, dabigatran treatment improved vascular integrity via sinusoidal protection and degraded HMGB-1 by endogenous TM enhancement on SECs, greatly ameliorating hepatic IRI.

Effects of Anticoagulants on Experimental Models of Established Chronic Liver Diseases: A Systematic Review and Meta-Analysis

OBJECTIVE

The role of anticoagulants in chronic liver diseases is inconclusive. A meta-analysis was thus undertaken to evaluate treatment-related survival and antifibrotic effects in animal models of chronic liver diseases.

METHODS

A systematic search of the literature took place (up to November 2020), screening for preclinical studies that evaluated anticoagulant effects in animal models of chronic liver diseases. We assessed the quality of methods and the certainty of evidence. Data on outcomes were extracted and pooled into random-effects models.

RESULTS

Sixteen studies proved eligible, each assessing anticoagulant use in animals with chronic liver diseases. Generally, the pooled evidence demonstrated that the administration of anticoagulants is preventive against fibrogenesis, as indicated by METAVIR fibrosis scores (risk ratio = 0.66, 95% confidence interval: 0.47 to 0.94), portal pressure determinations (mean difference = -1.39, 95% confidence interval: -2.33 to -0.44), inflammatory activity (mean difference = -169.69, 95% confidence interval: -257.64 to -81.74), and indices of hepatic injury, specifically alanine aminotransferase (mean difference = -82.7, 95% confidence interval: -107.36 to -58.04), aspartate aminotransferase (mean difference = -186.12, 95% confidence interval: -254.90 to -117.33), albumin (mean difference = 0.59, 95% confidence interval: 0.16 to 1.01), and total bilirubin (mean difference = -0.96, 95% confidence interval: -1.46 to -0.46), and it had no impact on animal survival (risk ratio = 1.03, 95% confidence interval: 0.94 to 1.13).

CONCLUSIONS

Our assessments indicate that in animal models of chronic liver diseases, anticoagulants may alleviate the degree of fibrosis evaluated by the METAVIR score system, portal pressure, inflammatory activity, and serum indices of hepatocellular injury, without impacting survival. High-quality experimental studies are still required.

Congestive Hepatopathy

Liver disease resulting from heart failure (HF) has generally been referred as “cardiac hepatopathy”. One of its main forms is congestive hepatopathy (CH), which results from passive venous congestion in the setting of chronic right-sided HF. The current spectrum of CH differs from earlier reports with HF, due to ischemic cardiomyopathy and congenital heart disease having surpassed rheumatic valvular disease. The chronic passive congestion leads to sinusoidal hypertension, centrilobular fibrosis, and ultimately, cirrhosis (“cardiac cirrhosis”) and hepatocellular carcinoma after several decades of ongoing injury. Contrary to primary liver diseases, in CH, inflammation seems to play no role in the progression of liver fibrosis, bridging fibrosis occurs between central veins to produce a “reversed lobulation” pattern and the performance of non-invasive diagnostic tests of liver fibrosis is poor. Although the clinical picture and prognosis is usually dominated by the underlying heart condition, the improved long-term survival of cardiac patients due to advances in medical and surgical treatments are responsible for the increased number of liver complications in this setting. Eventually, liver disease could become as clinically relevant as cardiac disease and further complicate its management.

Liver fibrosis is driven by protease-activated receptor-1 expressed by hepatic stellate cells in experimental chronic liver injury

BACKGROUND

Blood coagulation protease activity is proposed to drive hepatic fibrosis through activation of protease-activated receptors (PARs). Whole-body PAR-1 deficiency reduces experimental hepatic fibrosis, and in vitro studies suggest a potential contribution by PAR-1 expressed by hepatic stellate cells. However, owing to a lack of specific tools, the cell-specific role of PAR-1 in experimental hepatic fibrosis has never been formally investigated. Using a novel mouse expressing a conditional PAR-1 allele, we tested the hypothesis that PAR-1 expressed by hepatic stellate cells contributes to hepatic fibrosis.

METHODS

PAR-1flox/flox mice were crossed with mice expressing Cre recombinase controlled by the lecithin retinol acyltransferase (LRAT) promoter, which induces recombination in hepatic stellate cells. Male PAR-1flox/flox/LRATCre and PAR-1flox/flox mice were challenged twice weekly with carbon tetrachloride (CCl4, 1 mL/kg i.p.) for 6 weeks to induce liver fibrosis.

RESULTS

PAR-1 mRNA levels were reduced (>95%) in hepatic stellate cells isolated from PAR-1flox/flox/LRATCre mice. Hepatic stellate cell activation was evident in CCl4-challenged PAR-1flox/flox mice, indicated by increased α-smooth muscle actin labeling and induction of several profibrogenic genes. CCl4-challenged PAR-1flox/flox mice displayed robust hepatic collagen deposition, indicated by picrosirius red staining and type I collagen immunolabeling. Notably, stellate cell activation and collagen deposition were significantly reduced (>30%) in PAR-1flox/flox/LRATCre mice. Importantly, the reduction in liver fibrosis was not a consequence of reduced acute CCl4 hepatotoxicity in PAR-1flox/flox/LRATCre mice.

CONCLUSIONS

The results constitute the first direct experimental evidence that PAR-1 expressed by stellate cells directly promotes their profibrogenic phenotype and hepatic fibrosis in vivo.

Co-delivery of miR-29b and germacrone based on cyclic RGD-modified nanoparticles for liver fibrosis therapy

Hepatic stellate cells (HSCs) were activated and secreted excessive amounts of extracellular matrix (ECM) proteins during pathogenetic progress of liver fibrosis. Germacrone (GMO) and miR-29b can play an important role in inhibiting growth of HSCs and production of type I collagen. GMO and miR-29b were co-encapsulated into nanoparticles (NPs) based on poly(ethylene glycol)-block-poly(lactide-co-glycolide) (PEG-PLGA). Then, NPs were modified with cyclic RGD peptides (cRGDfK). cRGDfK is an effective ligand to bind integrin α_vβ₃ and increase the targeting ability for fibrotic liver. GMO- and miR-29b-loaded NPs exhibited great cytotoxicity to activated HSCs and significantly inhibited production of type I collagen. Liver fibrosis model of mice was induced by administration of carbon tetrachloride. Great targeting ability was achieved in liver fibrotic mice treated with cRGD-modified NPs. Significant ant-fibrotic effects have been presented based on hematoxylin and eosin (H&E), Masson and Sirius Red staining results of liver tissues collected from mice treated with drug-loaded NPs. All these results indicate GMO- and miR-29b-loaded cRGD-modified NPs have the potential for clinical use to treat liver fibrosis.

Chronic liver injury drives non-traditional intrahepatic fibrin(ogen) crosslinking via tissue transglutaminase

Essentials Fibrin clots are often implicated in the progression of liver fibrosis. Liver fibrosis was induced in transgenic mice with defects in clot formation or stabilization. Liver fibrosis and fibrin(ogen) deposition do not require fibrin polymerization or factor XIIIa. Fibrin(ogen) is an in vivo substrate of tissue transglutaminase in experimental liver fibrosis. SUMMARY: Background Intravascular fibrin clots and extravascular fibrin deposits are often implicated in the progression of liver fibrosis. However, evidence supporting a pathological role of fibrin in hepatic fibrosis is indirect and based largely on studies using anticoagulant drugs that inhibit activation of the coagulation protease thrombin, which has other downstream targets that promote fibrosis. Therefore, the goal of this study was to determine the precise role of fibrin deposits in experimental hepatic fibrosis. Methods Liver fibrosis was induced in mice expressing mutant fibrinogen insensitive to thrombin-mediated proteolysis (i.e. locked in the monomeric form), termed FibAEK mice, and factor XIII A2 subunit-deficient (FXIII-/- ) mice. Female wild-type mice, FXIII-/- mice and homozygous FibAEK mice were challenged with carbon tetrachloride (CCl4 ) twice weekly for 4 weeks or 6 weeks (1 mL kg-1 , intraperitoneal). Results Hepatic injury and fibrosis induced by CCl4 challenge were unaffected by FXIII deficiency or inhibition of thrombin-catalyzed fibrin polymer formation (in FibAEK mice). Surprisingly, hepatic deposition of crosslinked fibrin(ogen) was not reduced in CCl4 -challenged FXIII-/- mice or FibAEK mice as compared with wild-type mice. Rather, deposition of crosslinked hepatic fibrin(ogen) following CCl4 challenge was dramatically reduced in tissue transglutaminase-2 (TGM2)-deficient (TGM2-/- ) mice. However, the reduction in crosslinked fibrin(ogen) in TGM2-/- mice did not affect CCl4 -induced liver fibrosis. Conclusions These results indicate that neither traditional fibrin clots, formed by the thrombin-activated FXIII pathway nor atypical TGM2-crosslinked fibrin(ogen) contribute to experimental CCl4 -induced liver fibrosis. Collectively, the results indicate that liver fibrosis occurs independently of intrahepatic fibrin(ogen) deposition.