Angiogenesis in chronic liver disease and its complications

Liver fibrosis progression analyzed with AI predicts renal decline

Background & Aims

The relationship between biopsy-proven liver fibrosis progression and renal function decline in patients with metabolic dysfunction-associated steatotic liver disease (MASLD) has not been fully elucidated. We used an automated quantitative liver fibrosis assessment (qFibrosis) technique to investigate the temporal changes in regional liver fibrosis.

Methods

This retrospective longitudinal study included 68 MASLD patients and their paired formalin-fixed sections of liver biopsies. One hundred eighty-four fibrosis parameters were quantified in five different hepatic regions, including portal tract, peri-portal, zone 2, peri-central and central vein regions, and qFibrosis continuous values were calculated for all samples based on 10 fibrosis parameters using qFibrosis assessment. Liver fibrosis progression (QLF+, n = 18) and regression (QLF-, n = 23) was defined as at least a 20% relative change in qFibrosis over a 23-month follow-up. Renal function decline was assessed by estimated glomerular filtration rate (eGFR) changes.

Results

The eGFR decline was greater in the QLF+ group (106.53 ± 13.71 ml/min/1.73 m2 vs. 105.28 ± 12.46 ml/min/1.73 m2) than in the QLF- group (110.87 ± 14.58 ml/min/1.73 m2 vs. 114.18 ± 14.81 ml/min/1.73 m2). In addition, liver fibrosis changes in the central vein and pericentral regions were more strongly associated with eGFR decline than in periportal, zone 2 and portal tract regions. We combined these parameters to construct a prediction model, which better differentiated eGFR decline (a cut-off value of qFibrosis combined index = 0.52, p <0.001).

Conclusions

A decline in renal function is significantly related to liver fibrosis progression in MASLD. Regional qFibrosis assessment may efficiently predict eGFR decline, thus highlighting the importance of assessing renal function in patients with MASLD with worsening liver fibrosis.

Impact and implications

The study shows that liver fibrosis progression assessed by qFibrosis may be associated with renal function decline, which provides a new perspective for understanding complex pathological processes. A combination of artificial intelligence and digital pathology may earlier and more precisely quantify the progression of regional liver fibrosis, thus better identifying changes in renal function. This opens the possibility of early interventions, which are essential to improve patients' outcomes.

The role of liver sinusoidal endothelial cells in metabolic dysfunction-associated steatotic liver diseases and liver cancer: mechanisms and potential therapies

Liver sinusoidal endothelial cells (LSECs), with their unique morphology and function, have garnered increasing attention in chronic liver disease research. This review summarizes the critical roles of LSECs under physiological conditions and in two representative chronic liver diseases: metabolic dysfunction-associated steatotic liver disease (MASLD) and liver cancer. Under physiological conditions, LSECs act as selective barriers, regulating substance exchange and hepatic blood flow. Interestingly, LSECs exhibit contrasting roles at different stages of disease progression: in the early stages, they actively resist disease advancement and help restore sinusoidal homeostasis; whereas in later stages, they contribute to disease worsening. During this transition, LSECs undergo capillarization, lose their characteristic markers, and become dysfunctional. As the disease progresses, LSECs closely interact with hepatocytes, hepatic stellate cells, various immune cells, and tumor cells, driving processes such as steatosis, inflammation, fibrosis, angiogenesis, and carcinogenesis. Consequently, targeting LSECs represents a promising therapeutic strategy for chronic liver diseases. Relevant therapeutic targets and potential drugs are summarized in this review.

Curcumol Attenuates Portal Hypertension and Collateral Shunting Via Inhibition of Extrahepatic Angiogenesis in Cirrhotic Rats

Liver cirrhosis can cause disturbances in blood circulation in the liver, resulting in impaired portal blood flow and ultimately increasing portal venous pressure. Portal hypertension induces portal-systemic collateral formation and fatal complications. Extrahepatic angiogenesis plays a crucial role in the development of portal hypertension. Curcumol is a sesquiterpenoid derived from the rhizome of Curcumae Rhizoma and has been confirmed to alleviate liver fibrosis by inhibiting angiogenesis. Therefore, our study was designed to explore the effects of curcumol on extrahepatic angiogenesis and portal hypertension. To induce cirrhosis, Sprague Dawley rats underwent bile duct ligation (BDL) surgery. Rats received oral administration with curcumol (30 mg/kg/d) or vehicle (distilled water) starting on day 15 following surgery, when BDL-induced liver fibrosis had developed. The effect of curcumol was assessed on day 28, which is the typical time of BDL-induced cirrhosis. The results showed that curcumol markedly reduced portal pressure in cirrhotic rats. Curcumol inhibited abnormal splanchnic inflow, mitigated liver injury, improved liver fibrosis, and attenuated portal-systemic collateral shunting in cirrhotic rats. These protective effects were partially attributed to the inhibition on mesenteric angiogenesis by curcumol. Mechanically, curcumol partially reversed the BDL-induced activation of the JAK2/STAT3 signaling pathway in cirrhotic rats. Collectively, curcumol attenuates portal hypertension in liver cirrhosis by suppressing extrahepatic angiogenesis through inhibiting the JAK2/STAT3 signaling pathway.

Nanocarrier-Mediated RNA Delivery Platform as a Frontier Strategy for Hepatic Disease Treatment: Challenges and Opportunities

Hepatic diseases cause serious public health problems worldwide, and there is an urgent need to develop effective therapeutic agents. In recent years, significant progress is made in RNA therapy, and RNA molecules, such as mRNAs, siRNAs, miRNAs, and RNA aptamers, are shown to provide significant advantages in the treatment of hepatic diseases. However, the drawbacks of RNAs, such as their poor biological stability, easy degradation by nucleases in vivo, low bioavailability, and low concentrations in target tissues, significantly limit the clinical application of RNA-based drugs. Therefore, exploring and developing effective nanoscale delivery platforms for RNA therapeutics are of immense value. This review focuses on the different types of hepatic diseases and RNA therapeutics, summarizing various nanoscale delivery platforms and their strengths and weaknesses. Finally, the current status and future prospects of nanoscale delivery systems for RNA therapy are discussed.

Impacts of low birthweight on kidney development and intergenerational growth of the offspring

Low birthweight (LBW) increases the risk of adult-onset diseases, including kidney diseases, with intergenerational consequences; however, the underlying mechanisms and effective interventions are unclear. To examine the cross-generational effects of LBW, we established an LBW mouse model through reduced uterine perfusion pressure (RUPP) and investigated the therapeutic potential of tadalafil, a phosphodiesterase 5 inhibitor, on LBW-associated consequences. RUPP-pups (R1) had lower fetal and birth weights, delayed renal development, and fewer glomeruli than Sham-pups. In adulthood, R1 mice exhibited persistently fewer glomeruli and elevated blood pressure, while Tadalafil-R1 mice showed reduced hypertension in both sexes and improved renal pathological changes in males. Additionally, pregnant R1 mice displayed inadequate gestational liver hypertrophy, impaired hepatic purine metabolism, and diminished placental angiogenesis, resulting in fetal growth restriction in the subsequent generation. These findings underscore the lasting impact of LBW on adult health and future generations and suggest tadalafil's potential to mitigate LBW-associated risks.

Single-cell RNA sequencing of cystic fibrosis liver disease explants reveals endothelial complement activation

BACKGROUND & AIMS

Cystic fibrosis (CF) is considered a multisystemic disorder in which CF-associated liver disease (CFLD) is the third most common cause of mortality. Currently, no effective treatment is available for CFLD because its pathophysiology is still unclear. Interestingly, CFLD exhibits identical vascular characteristics as non-cirrhotic portal hypertension, recently classified as porto-sinusoidal vascular disorders (PSVD).

METHODS

Since endothelial cells (ECs) are an important component in PSVD, we performed single-cell RNA sequencing (scRNA-seq) on four explant livers from CFLD patients to identify differential endothelial characteristics which could contribute to the disease. We comprehensively characterized the endothelial compartment and compared it with publicly available scRNA-seq datasets from cirrhotic and healthy livers. Key gene signatures were validated ex vivo on patient tissues.

RESULTS

We found that ECs from CF liver explants are more closely related to healthy than cirrhotic patients. In CF patients we also discovered a distinct population of liver sinusoidal ECs-coined CF LSECs-upregulating genes involved in the complement cascade and coagulation. Finally, our immunostainings further validated the predominant periportal location of CF LSECs.

CONCLUSIONS

Our work showed novel aspects of human liver ECs at the single-cell level thereby supporting endothelial involvement in CFLD, and reinforcing the hypothesis that ECs could be a driver of PSVD. Therefore, considering the vascular compartment in CF and CFLD may help developing new therapeutic approaches for these diseases.

Depletion of Activated Hepatic Stellate Cells and Capillarized Liver Sinusoidal Endothelial Cells Using a Rationally Designed Protein for Nonalcoholic Steatohepatitis and Alcoholic Hepatitis Treatment

Nonalcoholic steatohepatitis (NASH) and alcoholic hepatitis (AH) affect a large part of the general population worldwide. Dysregulation of lipid metabolism and alcohol toxicity drive disease progression by the activation of hepatic stellate cells and the capillarization of liver sinusoidal endothelial cells. Collagen deposition, along with sinusoidal remodeling, alters sinusoid structure, resulting in hepatic inflammation, portal hypertension, liver failure, and other complications. Efforts were made to develop treatments for NASH and AH. However, the success of such treatments is limited and unpredictable. We report a strategy for NASH and AH treatment involving the induction of integrin αvβ3-mediated cell apoptosis using a rationally designed protein (ProAgio). Integrin αvβ3 is highly expressed in activated hepatic stellate cells (αHSCs), the angiogenic endothelium, and capillarized liver sinusoidal endothelial cells (caLSECs). ProAgio induces the apoptosis of these disease-driving cells, therefore decreasing collagen fibril, reversing sinusoid remodeling, and reducing immune cell infiltration. The reversal of sinusoid remodeling reduces the expression of leukocyte adhesion molecules on LSECs, thus decreasing leukocyte infiltration/activation in the diseased liver. Our studies present a novel and effective approach for NASH and AH treatment.

Significance of the sFlt-1/PlGF Ratio in Certain Cohorts - What Needs to be Considered?

The sFlt-1/PlGF ratio is an established tool in clinical practice, where it is part of a diagnostic algorithm and informs the prognosis of preeclampsia (PE). Maternal and gestational comorbidities can affect the performance of the sFlt-1/PlGF ratio and its constituent elements, and a good understanding of the potential pitfalls is required. The objective of this paper was to provide a current narrative review of the literature on the diagnostic and predictive performance of the sFlt-1/PlGF ratio in specific patient cohorts. Potential factors which can negatively affect the clinical interpretability and applicability of the sFlt-1/PlGF ratio include chronic kidney disease, twin pregnancy, and maternal obesity. Pathophysiological mechanisms related to these factors and disorders can result in different concentrations of sFlt-1 and/or PlGF in maternal blood, meaning that the use of standard cut-off values in specific cohorts can lead to errors. To what extent the cut-off values should be adapted in certain patient cohorts can only be clarified in large prospective cohort studies. This applies to the use of the ratio both for diagnosis and prognosis.

SH-Alb inhibits phenotype remodeling of pro-fibrotic macrophage to attenuate liver fibrosis through SIRT3-SOD2 axis

Albumin has a variety of biological functions, such as immunomodulatory and antioxidant activity, which depends largely on its thiol activity. However, in clinical trials, the treatment of albumin by injection of commercial human serum albumin (HSA) did not achieve the desired results. Here, we constructed reduced modified albumin (SH-Alb) for in vivo and in vitro experiments to investigate the reasons why HSA did not achieve the expected effects. SH-Alb was found to delay the progression of liver fibrosis in mice by alleviating liver inflammation and oxidative stress. Although R-Alb also has some of the above roles, the effect of SH-Alb is more remarkable. Mechanism studies have shown that SH-Alb reduces the release of pro-inflammatory and pro-fibrotic cytokine through the mitogen-activated protein kinase (MAPK) signaling pathway. In addition, SH-Alb deacetylates SOD2, a key enzyme of mitochondrial reactive oxygen species (ROS) production, by promoting the expression of SIRT3, thereby reducing the accumulation of ROS. Finally, macrophages altered by R-Alb or SH-Alb can inhibit the activation of hepatic stellate cells and endothelial cells, further delaying the progression of liver fibrosis. These results indicate that SH-Alb can remodel the phenotype of macrophages, thereby affecting the intrahepatic microenvironment and delaying the process of liver fibrosis. It provides a good foundation for the application of albumin in clinical treatment.

A Review of Terlipressin in Hepatorenal Syndrome: Targeting Endothelial Dysfunction and Subsequent Cardiovascular Adverse Events

Hepatorenal syndrome (HRS) is a serious complication of decompensated liver cirrhosis that results in acute kidney injury (AKI). The mortality rate is high. Endothelial dysfunction secondary to liver cirrhosis is a key driver of the development of portal hypertension, which is eventually complicated by ascites and HRS. Ultimately, splanchnic vasodilation and excess gut lymph production result in ascites, low effective arterial blood volume, and maladaptive compensatory mechanisms that contribute to renal hypoperfusion and injury. While the only curative treatment is liver transplantation, vasoconstrictors and albumin have been the mainstay of treatment for candidates who are ineligible or waiting for transplantation. On September 14, 2022, terlipressin, a V1 vasopressin receptor agonist, was approved by the Food and Drug Administration for the treatment of HRS-AKI. In clinical trials, terlipressin plus albumin have been superior to albumin alone and equivocal to noradrenaline plus albumin in renal function improvement. Terlipressin, however, does not improve survival, is costly, and is associated with severe adverse events-including severe cardiac and vascular complications. The aim of this review is to provide an overview of terlipressin pharmacology, adverse events-with a focus on cardiovascular complications-and comparative randomized controlled trials that resulted in the Food and Drug Administration's approval of terlipressin. New literature since its approval and ongoing clinical trials will also be highlighted.

Exploring shared molecular signatures and regulatory mechanisms in nonalcoholic steatohepatitis and inflammatory bowel disease using integrative bioinformatics analysis

The co-existence of inflammatory bowel disease (IBD) and non-alcoholic steatohepatitis (NASH) has raised interest in identifying shared molecular mechanisms and potential therapeutic targets. However, the relationship between these two diseases remains unclear and effective medical treatments are still lacking. Through the bioinformatics analysis in this study, 116 shared differentially expressed genes (SDEGs) were identified between IBD and NASH datasets. GO and KEGG pathway analyses revealed significant involvement of SDEGs in apoptotic processes, cell death, defense response, cytokine and chemokine activity, and signaling pathways. Furthermore, weighted gene co-expression network analysis (WGCNA) identified five shared signature genes associated specifically with IBD and NASH, they were CXCL9, GIMAP2, ADAMTS5, GRAP, and PRF1. These five genes represented potential diagnostic biomarkers for distinguishing patients with diseases from healthy individuals by using two classifier algorithms and were positively related to autophagy, ferroptosis, angiogenesis, and immune checkpoint factors in the two diseases. Additionally, single-cell analysis of IBD and NASH samples highlighted the expression of regulatory genes in various immune cell subtypes, emphasizing their significance in disease pathogenesis. Our work elucidated the shared signature genes and regulatory mechanisms of IBD and NASH, which could provide new potential therapies for patients with IBD and NASH.

From hepatitis B virus infection to acute-on-chronic liver failure: The dynamic role of hepatic macrophages

Acute-on-chronic liver failure (ACLF) is a progressive disease that is associated with rapid worsening of clinical symptoms and high mortality. A multicentre prospective study from China demonstrated that patients with hepatitis B virus-related ACLF (HBV-ACLF) exhibited worse clinical characteristics and higher mortality rates compared to non-HBV-ACLF patients. Immune dysregulation is closely linked to the potential mechanisms of initiation and progression of ACLF. Innate immune response, which is represented by monocytes/macrophages, is up-regulated across ACLF development. This suggests that monocytes/macrophages play an essential role in maintaining the immune homeostasis of ACLF. Information that has been published in recent years shows that the immune status and function of monocytes/macrophages vary in ACLF precipitated by different chronic liver diseases. Monocytes/macrophages have an immune activation effect in hepatitis B-precipitated-ACLF, but they exhibit an immune suppression in cirrhosis-precipitated-ACLF. Therefore, this review aims to explain whether this difference affects the clinical outcome in HBV-ACLF patients as well as the mechanisms involved. We summarize the novel findings that highlight the dynamic polarization phenotype and functional status of hepatic macrophages from the stage of HBV infection to ACLF development. Moreover, we discuss how different HBV-related liver disease tissue microenvironments affect the phenotype and function of hepatic macrophages. In summary, increasing developments in understanding the differences in immune phenotype and functional status of hepatic macrophages in ACLF patients will provide new perspectives towards the effective restoration of ACLF immune homeostasis.

The Interplay between Liver Sinusoidal Endothelial Cells, Platelets, and Neutrophil Extracellular Traps in the Development and Progression of Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) represents a societal burden due to the lack of effective treatment and incomplete pathophysiology understanding. This review explores the intricate connections among liver sinusoidal endothelial cells (LSECs), platelets, neutrophil extracellular traps (NETs), and coagulation disruptions in MASLD pathogenesis. In MASLD's early stages, LSECs undergo capillarization and dysfunction due to excessive dietary macronutrients and gut-derived products. Capillarization leads to ischemic changes in hepatocytes, triggering pro-inflammatory responses in Kupffer cells (KCs) and activating hepatic stellate cells (HSCs). Capillarized LSECs show a pro-inflammatory phenotype through adhesion molecule overexpression, autophagy loss, and increased cytokines production. Platelet interaction favors leucocyte recruitment, NETs formation, and liver inflammatory foci. Liver fibrosis is facilitated by reduced nitric oxide, HSC activation, profibrogenic mediators, and increased angiogenesis. Moreover, platelet attachment, activation, α-granule cargo release, and NETs formation contribute to MASLD progression. Platelets foster fibrosis and microthrombosis, leading to parenchymal extinction and fibrotic healing. Additionally, platelets promote tumor growth, epithelial-mesenchymal transition, and tumor cell metastasis. MASLD's prothrombotic features are exacerbated by insulin resistance, diabetes, and obesity, manifesting as increased von Willebrand factor, platelet hyperaggregability, hypo-fibrinolysis, and a prothrombotic fibrin clot structure. Improving LSEC health and using antiplatelet treatment appear promising for preventing MASLD development and progression.

Linking inflammation and angiogenesis with fibrogenesis: Expression of FXIIIA, MMP-9, and VEGF in oral submucous fibrosis

OBJECTIVES

Interplay of Factor XIIIa (FXIIIa), a transglutaminase, responsible for cross-linking of matrix proteins, Matrix Metalloproteinase-9 (MMP-9), a gelatinase, and Vascular Endothelial Growth Factor (VEGF), an angiogenic inducer, were studied in relation to fibrogenesis and disease progression in oral submucous fibrosis (OSMF).

MATERIAL AND METHODS

Immunohistochemical expression of markers was studied in 60 formalin-fixed paraffin-embedded tissue blocks of OSMF and 20 normal oral mucosal tissues. FXIIIa was studied quantitatively while MMP-9 and VEGF were assessed semi-quantitatively. Expression was compared with histopathological grades of OSMF.

RESULTS

FXIIIa expression significantly increased in OSMF (p-value 0.000). However, expression decreased and cells became quiescent with increasing grades (p-value 0.000). MMP-9 (p-value epithelium 0.011, p-value connective tissue 0.000) and VEGF expression (p-value epithelium 0.000, connective tissue 0.000) increased in OSMF. A negative correlation between FXIIIa and MMP-9 (-0.653) in early grade (p-value of 0.021) and a positive correlation between FXIIIa and VEGF (0.595) (p-value of 0.032) was found in the moderate grade OSMF. Regression analysis showed a significant association (p<0.01) of FXIIIa in OSMF and with increasing grades of OSMF.

CONCLUSION

FXIIIa may play a crucial role in initiation of fibrosis in OSMF. MMP-9 may have a diverse role to play in OSMF as a regulator of fibrosis. VEGF may show an angio-fibrotic switch and contribute to fibrosis in OSMF. These cytokines may show altered function and can contribute to fibrosis and chronicity of disease due to changes in the microenvironment. Tissue stiffness in OSMF itself creates an environment that enhances the chronicity of the disease.

Semaglutide reduces tumor burden in the GAN diet-induced obese and biopsy-confirmed mouse model of NASH-HCC with advanced fibrosis

Non-alcoholic steatohepatitis (NASH) is emerging as a major cause of hepatocellular carcinoma (HCC), however, it is not resolved if compounds in late-stage clinical development for NASH may have additional therapeutic benefits in NASH-driven HCC (NASH-HCC). Here, we profiled monotherapy with semaglutide (glucagon-like-receptor-1 receptor agonist) and lanifibranor (pan-peroxisome proliferator-activated receptor agonist) in a diet-induced obese (DIO) mouse model of NASH-HCC. Disease progression was characterized in male C57BL/6 J mice fed the GAN (Gubra Amylin NASH) diet high in fat, fructose and cholesterol for 12-72 weeks (n = 15 per group). Other GAN DIO-NASH-HCC mice fed the GAN diet for 54 weeks and with biopsy-confirmed NASH (NAFLD Activity Score ≥ 5) and advanced fibrosis (stage F3) received vehicle (n = 16), semaglutide (30 nmol/kg, s.c., n = 15), or lanifibranor (30 mg/kg, p.o., n = 15) once daily for 14 weeks. GAN DIO-NASH-HCC mice demonstrated progressive NASH, fibrosis and HCC burden. Tumors presented with histological and molecular signatures of poor prognostic HCC. Consistent with clinical trial outcomes in NASH patients, both lanifibranor and semaglutide improved NASH while only lanifibranor reduced fibrosis in GAN DIO-NASH-HCC mice. Notably, only semaglutide reduced tumor burden in GAN DIO-NASH-HCC mice. In conclusion, the GAN DIO-NASH-HCC mouse is a clinical translational model of NASH-HCC. Semaglutide improves both NASH and tumor burden in GAN DIO-NASH-HCC mice, highlighting the suitability of this preclinical model for profiling novel drug therapies targeting NASH-HCC.

Research progress of traditional Chinese medicine in improving hepatic fibrosis based on inhibiting pathological angiogenesis

Hepatic fibrosis is the formation of scar tissue in the liver. This scar tissue replaces healthy liver tissue and can lead to liver dysfunction and failure if left untreated. It is usually caused by chronic liver disease, such as hepatitis B or C, alcohol abuse, or non-alcoholic fatty liver disease. Pathological angiogenesis plays a crucial role in the development of hepatic fibrosis by promoting the growth of new blood vessels in the liver. These new vessels increase blood flow to the damaged areas of the liver, which triggers the activation of hepatic stellate cells (HSCs). HSCs are responsible for producing excess collagen and other extracellular matrix proteins that contribute to the development of fibrosis. Pathological angiogenesis plays a crucial role in the development of hepatic fibrosis by promoting the growth of new blood vessels in the liver. These new vessels increase blood flow to the damaged areas of the liver, which triggers the activation of HSCs. HSCs are responsible for producing excess collagen and other extracellular matrix proteins that contribute to the development of fibrosis. Traditional Chinese medicine (TCM) has been found to target pathological angiogenesis, thereby providing a potential treatment option for hepatic fibrosis. Several studies have demonstrated that TCM exhibits anti-angiogenic effects by inhibiting the production of pro-angiogenic factors, such as vascular endothelial growth factor and angiopoietin-2, and by reducing the proliferation of endothelial cells. Reviewing and highlighting the unique TCM recognition of treating hepatic fibrosis by targeting pathological angiogenesis may shed light on future hepatic fibrosis research.

Moringa oleifera and Autophagy: Evidence from In Vitro Studies on Chaperone-Mediated Autophagy in HepG2 Cancer Cells

Hepatocellular carcinoma (HCC) is the most prevalent primary liver cancer in Sub-Saharan African countries, including South Africa (SA). Given the limitations in current HCC therapeutics, there is an increasing need for alternative adjuvant therapeutic options. As such, several cell survival mechanisms, such as autophagy, have been identified as potential adjuvant therapeutic targets in HCC treatment. Of the three most established autophagic pathways, the upregulation of chaperone-mediated autophagy (CMA) has been extensively described in various cancer cells, including HCC cells. CMA promotes tumor growth and chemotherapeutic drug resistance, thus contributing to HCC tumorigenesis. Therefore, the modulation of CMA serves as a promising adjuvant target for current HCC therapeutic strategies. Phytochemical extracts found in the medicinal plant, Moringa oleifera (MO), have been shown to induce apoptosis in numerous cancer cells, including HCC. MO leaves have the greatest abundance of phytochemicals displaying anticancer potential. However, the potential interaction between the pro-apoptotic effects of MO aqueous leaf extract and the survival-promoting role of CMA in an in vitro model of HCC remains unclear. This review aims to summarize the latest findings on the role of CMA, and MO in the progression of HCC.

Angiotensin-converting enzyme 2 improves liver fibrosis in mice by regulating autophagy of hepatic stellate cells

BACKGROUND

Liver fibrosis is the common pathological process associated with the occurrence and development of various chronic liver diseases. At present, there is still a lack of effective prevention and treatment methods in clinical practice. Hepatic stellate cell (HSC) plays a key role in liver fibrogenesis. In recent years, the study of liver fibrosis targeting HSC autophagy has become a hot spot in this research field. Angiotensin-converting enzyme 2 (ACE2) is a key negative regulator of renin-angiotensin system, and its specific molecular mechanism on autophagy and liver fibrosis needs to be further explored.

AIM

To investigate the effect of ACE2 on hepatic fibrosis in mice by regulating HSC autophagy through the Adenosine monophosphate activates protein kinases (AMPK)/mammalian target of rapamycin (mTOR) pathway.

METHODS

Overexpression of ACE2 in a mouse liver fibrosis model was induced by injection of liver-specific recombinant adeno-associated virus ACE2 vector (rAAV2/8-ACE2). The degree of liver fibrosis was assessed by histopathological staining and the biomarkers in mouse serum were measured by Luminex multifactor analysis. The number of apoptotic HSCs was assessed by terminal deoxynucleoitidyl transferase-mediated dUTP nick-end labeling (TUNEL) and immunofluorescence staining. Transmission electron microscopy was used to identify the changes in the number of HSC autophagosomes. The effect of ACE2 overexpression on autophagy-related proteins was evaluated by multicolor immunofluorescence staining. The expression of autophagy-related indicators and AMPK pathway-related proteins was measured by western blotting.

RESULTS

A mouse model of liver fibrosis was successfully established after 8 wk of intraperitoneal injection of carbon tetrachloride (CCl4). rAAV2/8-ACE2 administration reduced collagen deposition and alleviated the degree of liver fibrosis in mice. The serum levels of platelet-derived growth factor, angiopoietin-2, vascular endothelial growth factor and angiotensin II were decreased, while the levels of interleukin (IL)-10 and angiotensin- (1-7) were increased in the rAAV2/8-ACE2 group. In addition, the expression of alpha-smooth muscle actin, fibronectin, and CD31 was down-regulated in the rAAV2/8-ACE2 group. TUNEL and immunofluorescence staining showed that rAAV2/8-ACE2 injection increased HSC apoptosis. Moreover, rAAV2/8-ACE2 injection notably decreased the number of autophagosomes and the expression of autophagy-related proteins (LC3I, LC3II, Beclin-1), and affected the expression of AMPK pathway-related proteins (AMPK, p-AMPK, p-mTOR).

CONCLUSION

ACE2 overexpression can inhibit HSC activation and promote cell apoptosis by regulating HSC autophagy through the AMPK/mTOR pathway, thereby alleviating liver fibrosis and hepatic sinusoidal remodeling.

Portosystemic shunt placement reveals blood signatures for the development of hepatic encephalopathy through mass spectrometry

Elective transjugular intrahepatic portosystemic shunt (TIPS) placement can worsen cognitive dysfunction in hepatic encephalopathy (HE) patients due to toxins, including possible microbial metabolites, entering the systemic circulation. We conducted untargeted metabolomics on a prospective cohort of 22 patients with cirrhosis undergoing elective TIPS placement and followed them up to one year post TIPS for HE development. Here we suggest that pre-existing intrahepatic shunting predicts HE severity post-TIPS. Bile acid levels decrease in the peripheral vein post-TIPS, and the abundances of three specific conjugated di- and tri-hydroxylated bile acids are inversely correlated with HE grade. Bilirubins and glycerophosphocholines undergo chemical modifications pre- to post-TIPS and based on HE grade. Our results suggest that TIPS-induced metabolome changes can impact HE development, and that pre-existing intrahepatic shunting could be used to predict HE severity post-TIPS.

HBx promotes hepatocellular carcinoma progression by repressing the transcription level of miR-187-5p

HBV-associated hepatitis B virus x protein (HBx) plays multiple roles in the development of hepatocellular carcinoma. In our prior study, we discovered that miR-187-5p expression was inhibited by HBx. To investigate the underlying molecular mechanism of HBx-mediated miR-187-5p downregulation in hepatocellular carcinoma cells, effects of HBx and miR-187-5p on hepatoma carcinoma cell were observed, as well as their interactions. Through in vitro and in vivo experiments, we demonstrated that overexpression of miR-187-5p inhibited proliferation, migration, and invasion. Simultaneously, we observed a dysregulation in the expression of miR-187-5p in liver cancer cell lines, which may be attributed to transcriptional inhibition through the E2F1/FoxP3 axis. Additionally, we noted that HBx protein is capable of enhancing the expression of E2F1, a transcription factor that promotes the expression of FoxP3. In conclusion, our results suggest that the inhibitory effect of HBx on miR-187-5p is mediated through the E2F1/FoxP3 axis. As shown in this work, HBx promotes hepatoma carcinoma cell proliferation, migration, and invasion through the E2F1/FoxP3/miR-187 axis. It provides a theoretical basis for finding therapeutic targets that will help clinic treatment for HCC.

Anti-Angiogenic Effects of Natural Compounds in Diet-Associated Hepatic Inflammation

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are the most common causes of chronic liver disease and are increasingly emerging as a global health problem. Such disorders can lead to liver damage, resulting in the release of pro-inflammatory cytokines and the activation of infiltrating immune cells. These are some of the common features of ALD progression in ASH (alcoholic steatohepatitis) and NAFLD to NASH (non-alcoholic steatohepatitis). Hepatic steatosis, followed by fibrosis, lead to a continuous progression accompanied by angiogenesis. This process creates hypoxia, which activates vascular factors, initiating pathological angiogenesis and further fibrosis. This forms a vicious cycle of ongoing damage and progression. This condition further exacerbates liver injury and may contribute to the development of comorbidities, such as metabolic syndrome as well as hepatocellular carcinoma. Increasing evidence suggests that anti-angiogenic therapy may have beneficial effects on these hepatic disorders and their exacerbation. Therefore, there is a great interest to deepen the knowledge of the molecular mechanisms of natural anti-angiogenic products that could both prevent and control liver diseases. In this review, we focus on the role of major natural anti-angiogenic compounds against steatohepatitis and determine their potential therapeutic benefits in the treatment of liver inflammation caused by an imbalanced diet.

Hypoxia-inducible factor 1α/IL-6 axis in activated hepatic stellate cells aggravates liver fibrosis

Hepatic stellate cells (HSCs) upregulate hypoxia inducible factor 1 alpha (HIF-1α) expression in response to fibrosis-induced hypoxia. The mechanism by which HIF-1α promotes liver fibrosis in HSCs is not fully understood. In this study, we found that increased expression of α-SMA, HIF-1α and IL-6, as well as colocalization of α-SMA and HIF-1α, and HIF-1α and IL-6, were observed in liver fibrotic tissues of patients and a mouse model. HIF-1α expression induced IL-6 secretion in activated HSCs and the increase could be abolished by HIF-1α suppression or HIF1A gene knockdown. HIF-1α directly bound to the hypoxia response element (HRE) region in HSC IL6/Il6 promoters. Additionally, culturing naïve CD4 T cells with supernatant from HSCs in which HIF-1α is highly expressed increased IL-17A expression, and the expression could be abolished by HIF1A knockdown in LX2. In turn, the IL-17A-enriched supernatant induced IL-6 secretion in HSCs. Together, these results show that HIF-1α upregulates IL-6 expression in HSCs and induces IL-17A secretion through directly binding to the HRE of IL6 promoter.

ALK1 controls hepatic vessel formation, angiodiversity, and angiocrine functions in hereditary hemorrhagic telangiectasia of the liver

BACKGROUND AND AIMS

In hereditary hemorrhagic telangiectasia (HHT), severe liver vascular malformations are associated with mutations in the Activin A Receptor-Like Type 1 ( ACVRL1 ) gene encoding ALK1, the receptor for bone morphogenetic protein (BMP) 9/BMP10, which regulates blood vessel development. Here, we established an HHT mouse model with exclusive liver involvement and adequate life expectancy to investigate ALK1 signaling in liver vessel formation and metabolic function.

APPROACH AND RESULTS

Liver sinusoidal endothelial cell (LSEC)-selective Cre deleter line, Stab2-iCreF3 , was crossed with Acvrl1 -floxed mice to generate LSEC-specific Acvrl1 -deficient mice ( Alk1HEC-KO ). Alk1HEC-KO mice revealed hepatic vascular malformations and increased posthepatic flow, causing right ventricular volume overload. Transcriptomic analyses demonstrated induction of proangiogenic/tip cell gene sets and arterialization of hepatic vessels at the expense of LSEC and central venous identities. Loss of LSEC angiokines Wnt2 , Wnt9b , and R-spondin-3 ( Rspo3 ) led to disruption of metabolic liver zonation in Alk1HEC-KO mice and in liver specimens of patients with HHT. Furthermore, prion-like protein doppel ( Prnd ) and placental growth factor ( Pgf ) were upregulated in Alk1HEC-KO hepatic endothelial cells, representing candidates driving the organ-specific pathogenesis of HHT. In LSEC in vitro , stimulation or inhibition of ALK1 signaling counter-regulated Inhibitors of DNA binding (ID)1-3, known Alk1 transcriptional targets. Stimulation of ALK1 signaling and inhibition of ID1-3 function confirmed regulation of Wnt2 and Rspo3 by the BMP9/ALK1/ID axis.

CONCLUSIONS

Hepatic endothelial ALK1 signaling protects from development of vascular malformations preserving organ-specific endothelial differentiation and angiocrine signaling. The long-term surviving Alk1HEC-KO HHT model offers opportunities to develop targeted therapies for this severe disease.

Non-Parenchymal Cells and the Extracellular Matrix in Hepatocellular Carcinoma in Non-Alcoholic Fatty Liver Disease

Hepatocellular carcinoma (HCC) in the setting of non-alcoholic fatty liver disease (NAFLD)-related cirrhosis and even in the pre-cirrhotic state is increasing in incidence. NAFLD-related HCC has a poor clinical outcome as it is often advanced at diagnosis due to late diagnosis and systemic treatment response is poor due to reduced immune surveillance. Much of the focus of molecular research has been on the pathological changes in hepatocytes; however, immune cells, hepatic stellate cells, liver sinusoidal endothelial cells and the extracellular matrix may play important roles in the pathogenesis of NAFLD-related HCC as well. Here, we review the role of non-parenchymal cells in the liver in the pathogenesis of HCC in the context of NAFLD-NASH, with a particular focus on the innate and the adaptive immune system, fibrogenesis and angiogenesis. We review the key roles of macrophages, hepatic stellate cells (HSCs), T cells, natural killer (NK) cells, NKT cells and liver sinusoidal endothelial cells (LSECs) and the role of the extracellular matrix in hepatocarcinogenesis within the steatotic milieu.

Single-cell transcriptome analysis reveals liver injury induced by glyphosate in mice

BACKGROUND

Glyphosate (GLY), as the active ingredient of the most widely used herbicide worldwide, is commonly detected in the environment and living organisms, including humans. Its toxicity and carcinogenicity in mammals remain controversial. Several studies have demonstrated the hepatotoxicity of GLY; however, the underlying cellular and molecular mechanisms are still largely unknown.

METHODS

Using single-cell RNA sequencing (scRNA-seq), immunofluorescent staining, and in vivo animal studies, we analyzed the liver tissues from untreated and GLY-treated mice.

RESULTS

We generated the first scRNA-seq atlas of GLY-exposed mouse liver. GLY induced varied cell composition, shared or cell-type-specific transcriptional alterations, and dysregulated cell-cell communication and thus exerted hepatotoxicity effects. The oxidative stress and inflammatory response were commonly upregulated in several cell types. We also observed activation and upregulated phagocytosis in macrophages, as well as proliferation and extracellular matrix overproduction in hepatic stellate cells.

CONCLUSIONS

Our study provides a comprehensive single-cell transcriptional picture of the toxic effect of GLY in the liver, which offers novel insights into the molecular mechanisms of the GLY-associated hepatotoxicity.

Downregulation of miR-20b-5p Contributes to the Progression of Liver Fibrosis via the STAT3 Signaling Pathway In Vivo and In Vitro

BACKGROUND

Activated hepatic stellate cells (HSCs) are primarily involved in liver fibrosis and portal hypertension (PHT). We aimed to investigate the effect of miR-20b-5p on HSCs, liver fibrosis, and PHT.

METHODS

MiR-20b-5p expression in HSCs and in mouse liver fibrosis was determined by qPCR. Further, the effects of miR-20b-5p mimic on HSCs migration, proliferation, and apoptosis were investigated in vitro. A dual-luciferase reporter assay was performed to confirm the direct interaction between miR-20b-5p and STAT3. In vivo, mouse liver fibrosis was established by common bile duct ligation and intervened by agomiR-20b-5p. Sirius red staining and hydroxyproline content were used to evaluate collagen deposition. The α-SMA expression in the liver was detected by IHC and Western blotting. The STAT3 signaling pathway and its downregulated cytokines as well as portal pressure and angiogenesis were explored.

RESULTS

MiR-20b-5p was significantly downregulated during HSCs activation and in mouse liver fibrosis. The functional analyses demonstrated that miR-20b-5p inhibited cell proliferation, activation, and promoted apoptosis in HSCs in vitro. Moreover, miR-20b-5p regulated STAT3 expression by binding to the 3'UTR of its miRNA directly. Overexpression of miR-20b-5p facilitated HSC activation and proliferation by inhibiting the STAT3 signaling pathway. MiR-20b-5p overexpression suppressed the STAT3 and its downstream cytokines and ameliorated liver fibrosis in mice. The intra- and inter-hepatic angiogenesis were also effectively inhibited. The inhibition of liver fibrosis and neoangiogenesis contributed to the decrease of portal pressure.

CONCLUSIONS

MiR-20b-5p plays an important role in the fibrosis and angiogenesis of liver fibrosis by targeting the STAT3 signaling pathway.

Pre- and Post-Portosystemic Shunt Placement Metabolomics Reveal Molecular Signatures for the Development of Hepatic Encephalopathy

Hepatic encephalopathy (HE) is a common complication of advanced liver disease causing brain dysfunction. This is likely due to the accumulation of unfiltered toxins within the bloodstream. A known risk factor for developing or worsening HE is the placement of a transjugular intrahepatic portosystemic shunt (TIPS), which connects the pre-hepatic and post-hepatic circulation allowing some blood to bypass the dysfunctional liver and decreases portal hypertension. To better understand the pathophysiology of post-TIPS HE, we conducted a multi-center prospective cohort study employing metabolomic analyses on hepatic vein and peripheral vein blood samples from participants with cirrhosis undergoing elective TIPS placement, measuring chemical modifications and changes in concentrations of metabolites resulting from TIPS placement. In doing so, we identified numerous alterations in metabolites, including bile acids, glycerophosphocholines, and bilirubins possibly implicated in the development and severity of HE.

Carthami flos extract against carbon tetrachloride-induced liver fibrosis via alleviating angiogenesis in mice

BACKGROUND

Angiogenesis is a pathological phenomenon contribute to the development of chronic liver diseases, and anti-angiogenic therapy is an effective strategy to alleviate liver fibrosis. Carthami flos, a medicinal and edible herb, has the effects of improving blood circulation and regulating angiogenesis. However, the anti-angiogenic effect of Carthami flos in liver fibrosis remains unknown.

METHODS

We investigated the protective effect and therapeutic mechanism of Carthami flos extract (CFE) on carbon tetrachloride (CCl₄)-induced liver fibrosis in mice. The liver injury and collagen deposition were observed and evaluated by conducting HE, Masson, and Sirius red staining, testing the serum biochemical indexes (ALT, AST, ALP, γ-GT), and measuring the contents of HYP and four indexes of liver fiber (Col-IV, LN, HA, PC-III). Simultaneously, the expressions of α-SMA and Collagen-I were detected to determine the activation of hepatic stellate cells (HSCs). Subsequently, we measured the expressions of angiogenesis-related proteins such as PDGFRB, ERK1/2, p-ERK1/2, MEK, p-MEK, HIF-1α, VEGFA, VEGFR2, AKT and eNOS, and the mRNA levels of PDGFRB and VEGFA. Additionally, immunofluorescence staining and RT-qPCR assays were carried out to ascertain the expressions of continuous endothelial markers CD31, CD34 and vWF, and scanning electron microscope analysis was performed to observe the number of sinusoidal endothelial fenestrations.

RESULTS

Herein, we found that CFE could significantly reduce liver injury and collagen deposition, like the same effect of colchicine. CFE significantly alleviated CCl₄-induced liver injury and fibrosis, mainly manifested by reducing the levels of ALT, AST, ALP and γ-GT and decreasing the contents of HYP, Col-IV, LN, HA and PC-III. Additionally, CCl₄ promoted the activation of HSCs by increasing the expressions of α-SMA and Collagen-I, while CFE could rectify the condition. Moreover, CFE treatment prevented the CCl₄-induced the up-regulation of PDGFRB, p-MEK, p-ERK1/2, HIF-1α, VEGFA, VEGFR2, AKT and eNOS, suggesting that CFE might provide the protection against abnormal angiogenesis. In the meantime, the gradual disappearance of sinusoidal capillarization after CFE treatment was supported by the decreased the contents of CD31, CD34 and vWF, as well as the increased number of sinusoidal endothelial fenestrae.

CONCLUSION

In this study, the reduction of collagen deposition, the obstruction of HSCs activation, the inactivation of angiogenic signaling pathways and the weakening of hepatic sinusoidal capillarization jointly confirmed that CFE might be promising to resist angiogenesis in liver fibrosis via the PDGFRB/ERK/HIF-1α and VEGFA/AKT/eNOS signaling pathways. Nevertheless, as a potential therapeutic drug, the deeper mechanism of Carthami flos still needs to be further elucidated.

microRNAs-based diagnostic and therapeutic applications in liver fibrosis

Liver fibrosis is a process of over-extracellular matrix (ECM) aggregation and angiogenesis, which develops into cirrhosis and hepatocellular carcinoma (HCC). With the increasing pressure of liver fibrosis, new therapeutics to cure this disease requires much attention. Exosome-cargoed microRNAs (miRNAs) are emerging approaches in the precision of the liver fibrotic paradigm. In this review, we outlined the different types of hepatic cells derived miRNAs that drive intra-/extra-cellular interactive communication in liver fibrosis with different physiological and pathological processes. Specifically, we highlighted the possible mechanism of liver fibrosis pathogenesis associated with immune response and angiogenesis. In addition, potential clinical biomarkers and different stem cell transplant-derived miRNAs-based therapeutic strategies in liver fibrosis were summarized in this review. miRNAs-based approaches might help researchers devise new candidates for the cell-free treatment of liver fibrosis. This article is categorized under: RNA in Disease and Development > RNA in Disease.

ALS-L1023 from Melissa officinalis Alleviates Liver Fibrosis in a Non-Alcoholic Fatty Liver Disease Model

ALS-L1023 is an ingredient extracted from Melissa officinalis L. (Labiatae; lemon balm), which is known as a natural medicine that suppresses angiogenesis. Herein, we aimed to determine whether ALS-L1023 could alleviate liver fibrosis in the non-alcoholic fatty liver disease (NAFLD) model. C57BL/6 wild-type male mice (age, 6 weeks old) were fed a choline-deficient high-fat diet (CDHFD) for 10 weeks to induce NAFLD. For the next 10 weeks, two groups of mice received the test drug along with CDHFD. Two doses (a low dose, 800 mg/kg/day; and a high dose, 1200 mg/kg/day) of ALS-L1023 were selected and mixed with feed for administration. Obeticholic acid (OCA; 10 mg/kg/day) was used as the positive control. Biochemical analysis revealed that the ALS-L1023 low-dose group had significantly decreased alanine transaminase and aspartate transaminase. The area of fibrosis significantly decreased due to the administration of ALS-L1023, and the anti-fibrotic effect of ALS-L1023 was greater than that of OCA. RNA sequencing revealed that the responder group had lower expression of genes related to the hedgehog-signaling pathway than the non-responder group. ALS-L1023 may exert anti-fibrotic effects in the NAFLD model, suggesting that it may provide potential benefits for the treatment of liver fibrosis.

Mechanism of paracrine communications between hepatic progenitor cells and endothelial cells

Hepatic progenitor cells (HPCs) are facultative tissue-specific stem cells lining reactive ductules, which are ubiquitously observed in chronic liver diseases and cancer. Although previous research mainly focused on their contribution to liver regeneration, it turned out that in vivo differentiation of HPCs into hepatocytes only occurs after extreme injury. While recent correlative evidence implies the association of HPCs with disease progression, their exact role in pathogenesis remains largely unknown. Our previous research demonstrated that HPCs expressing angiogenic paracrine factors accumulate in the peritumoral area and are positively correlated with the extent of intratumoral cell proliferation and angiogenesis in the livers of patients with liver cancer. Given the crucial roles of angiogenesis in liver disease progression and carcinogenesis, we aimed to test the hypothesis that HPCs secrete paracrine factors to communicate with endothelial cells, to determine molecular mechanisms mediating HPCs-endothelial interactions, and to understand how the paracrine function of HPCs is regulated. HPCs promoted viability and tubulogenesis of human umbilical vein endothelial cells (HUVECs) and upregulated genes known to be involved in angiogenesis, endothelial cell function, and disease progression in a paracrine manner. The paracrine function of HPCs as well as expression of colony stimulating factor 1 (CSF1) were inhibited upon differentiation of HPCs toward hepatocytes. Inhibition of CSF1 receptor partly suppressed the paracrine effects of HPCs on HUVECs. Taken together, our study indicates that inhibition of the paracrine function of HPCs through modulation of their differentiation status and inhibition of CSF1 signaling is a promising strategy for inhibition of angiogenesis during pathological progression.

In Vitro Generation of Luminal Vasculature in Liver Organoids: From Basic Vascular Biology to Vascularized Hepatic Organoids

Liver organoids have gained much attention in recent years for their potential applications to liver disease modeling and pharmacologic drug screening. Liver organoids produced in vitro reflect some aspects of the in vivo physiological and pathological conditions of the liver. However, the generation of liver organoids with perfusable luminal vasculature remains a major challenge, hindering precise and effective modeling of liver diseases. Furthermore, vascularization is required for large organoids or assembloids to closely mimic the complexity of tissue architecture without cell death in the core region. A few studies have successfully generated liver organoids with endothelial cell networks, but most of these vascular networks produced luminal structures after being transplanted into tissues of host animals. Therefore, formation of luminal vasculature is an unmet need to overcome the limitation of liver organoids as an in vitro model investigating different acute and chronic liver diseases. Here, we provide an overview of the unique features of hepatic vasculature under pathophysiological conditions and summarize the biochemical and biophysical cues that drive vasculogenesis and angiogenesis in vitro. We also highlight recent progress in generating vascularized liver organoids in vitro and discuss potential strategies that may enable the generation of perfusable luminal vasculature in liver organoids.

A strategy of vascular-targeted therapy for liver fibrosis

BACKGROUND AND AIMS

No effective treatments are available for liver fibrosis. Angiogenesis is deeply involved in liver fibrogenesis. However, current controversial results suggest it is difficult to treat liver fibrosis through vascular targeting. There are three different microvessels in liver: portal vessels, liver sinusoids, and central vessels. The changes and roles for each of the three different vessels during liver fibrogenesis are unclear. We propose that they play different roles during liver fibrogenesis, and a single vascular endothelial cell (EC) regulator is not enough to fully regulate these three vessels to treat liver fibrosis. Therefore, a combined regulation of multiple different EC regulatory signaling pathway may provide new strategies for the liver fibrosis therapy. Herein, we present a proof-of-concept strategy by combining the regulation of leukocyte cell-derived chemotaxin 2 (LECT2)/tyrosine kinase with immunoglobulin-like and epidermal growth factor-like domains 1 signaling with that of vascular endothelial growth factor (VEGF)/recombinant VEGF (rVEGF) signaling.

APPROACH AND RESULTS

The CCl₄ -induced mouse liver fibrosis model and NASH model were both used. During fibrogenesis, vascular changes occurred at very early stage, and different liver vessels showed different changes and played different roles: decreased portal vessels, increased sinusoid capillarization and the increased central vessels the increase of portal vessels alleviates liver fibrosis, the increase of central vessels aggravates liver fibrosis, and the increase of sinusoid capillarization aggravates liver fibrosis. The combinational treatment of adeno-associated viral vector serotype 9 (AAV9)-LECT2-short hairpin RNA (shRNA) and rVEGF showed improved therapeutic effects, but it led to serious side effects. The combination of AAV9-LECT2-shRNA and bevacizumab showed both improved therapeutic effects and decreased side effects.

CONCLUSIONS

Liver vascular changes occurred at very early stage of fibrogenesis. Different vessels play different roles in liver fibrosis. The combinational treatment of AAV9-LECT2-shRNA and bevacizumab could significantly improve the therapeutic effects on liver fibrosis.

Olmesartan Improves Hepatic Sinusoidal Remodeling in Mice with Carbon Tetrachloride-Induced Liver Fibrosis

Aim

In mice with liver fibrosis produced by carbon tetrachloride (CCl₄), the effects of olmesartan on intrahepatic angiogenesis and sinusoidal remodeling will be evaluated.

Methods

By injecting CCl₄ into the peritoneal cavity, we established a mouse model of liver fibrosis. Using Sirius red and Masson trichrome staining, the extent of liver fibrosis in the animals was determined. Using immunohistochemical labeling and western blotting, the level of α-smooth muscle actin (α-SMA) expression, a characteristic of hepatic stellate cell activation, was assessed. Electron microscopy was used to determine the effect of olmesartan on hepatic sinusoidal capillarization, and immunohistochemical labeling was used to determine the expression levels of endothelial and basement membrane proteins in mouse liver tissues. Platelet-derived growth factor (PDGF), IL-10, vascular endothelial growth factor (VEGF), and angiotensin II levels in mouse serum were measured by Luminex multifactor analysis and ELISA. Olmesartan's effect on the angiotensin II type 1 receptor (AT1R) and the VEGF receptor (VEGFR) was evaluated using western blotting.

Results

Olmesartan reduced CCl₄-induced inflammatory cell infiltration and collagen deposition to alleviate liver fibrosis. α-SMA expression was decreased, and HSC activation was inhibited in mouse liver tissues by olmesartan treatment. In addition, hepatic sinusoidal capillarization was improved under the action of olmesartan. The expression of collagen IV, fibronectin, CD31, and von Willebrand factor (VWF) in the olmesartan group was also markedly downregulated. In fibrotic mice, olmesartan medication decreased the levels of PDGF, VEGF, and angiotensin II, but it increased the level of IL-10. Moreover, olmesartan reduced the expression of VEGFR-1, VEGFR-2, and AT1R relative to CCl₄-induced liver fibrosis.

Conclusions

In mice with CCl₄-induced fibrosis, olmesartan lowers angiogenesis and improves hepatic sinusoidal remodeling, according to our findings. By acting on the angiotensin II-AT1R-VEGF axis, this is achieved.

Development of a classification method for mild liver fibrosis using non-contrast CT image

PURPOSE

Detection of early-stage liver fibrosis has direct clinical implications on patient management and treatment. The aim of this paper is to develop a non-invasive, cost-effective method for classifying liver disease between "non-fibrosis" (F0) and "fibrosis" (F1-F4), and to evaluate the classification performance quantitatively.

METHODS

Image data from 75 patients who underwent a simultaneous liver biopsy and non-contrast CT examination were used for this study. Non-contrast CT image texture features such as wavelet-based features, standard deviation of variance filter, and mean CT number were calculated in volumes of interest (VOIs) positioned within the liver parenchyma. In addition, a combined feature was calculated using logistic regression with L2-norm regularization to further improve fibrosis detection. Based on the final pathology from the liver biopsy, the patients were labelled either as "non-fibrosis" or "fibrosis". Receiver-operating characteristic (ROC) curve, area under the ROC curve (AUROC), specificity, sensitivity, and accuracy were determined for the algorithm to differentiate between "non-fibrosis" and "fibrosis".

RESULTS

The combined feature showed the highest classification performance with an AUROC of 0.86, compared to the wavelet-based feature (AUROC, 0.76), the standard deviation of variance filter (AUROC, 0.65), and mean CT number (AUROC, 0.84). The combined feature's specificity, sensitivity, and accuracy were 0.66, 0.88, and 0.76, respectively, showing the most promising results.

CONCLUSION

A new non-invasive and cost-effective method was developed to classify liver diseases between "non-fibrosis" (F0) and "fibrosis" (F1-F4). The proposed method makes it possible to detect liver fibrosis in asymptomatic patients using non-contrast CT images for better patient management and treatment.

The Crosstalk Between Liver Sinusoidal Endothelial Cells and Hepatic Microenvironment in NASH Related Liver Fibrosis

Chronic liver injury can be caused by many factors, including virus infection, alcohol intake, cholestasis and abnormal fat accumulation. Nonalcoholic steatohepatitis (NASH) has become the main cause of liver fibrosis worldwide. Recently, more and more evidences show that hepatic microenvironment is involved in the pathophysiological process of liver fibrosis induced by NASH. Hepatic microenvironment consists of various types of cells and intercellular crosstalk among different cells in the liver sinusoids. Liver sinusoidal endothelial cells (LSECs), as the gatekeeper of liver microenvironment, play an irreplaceable role in the homeostasis and alterations of liver microenvironment. Many recent studies have reported that during the progression of NASH to liver fibrosis, LSECs are involved in various stages mediated by a series of mechanisms. Therefore, here we review the key role of crosstalk between LSECs and hepatic microenvironment in the progression of NASH to liver fibrosis (steatosis, inflammation, and fibrosis), as well as promising therapeutic strategies targeting LSECs.

Intercellular crosstalk of liver sinusoidal endothelial cells in liver fibrosis, cirrhosis and hepatocellular carcinoma

Intercellular crosstalk among various liver cells plays an important role in liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). Capillarization of liver sinusoidal endothelial cells (LSECs) precedes fibrosis and accumulating evidence suggests that the crosstalk between LSECs and other liver cells is critical in the development and progression of liver fibrosis. LSECs dysfunction, a key event in the progression from fibrosis to cirrhosis, and subsequently obstruction of hepatic sinuses and increased intrahepatic vascular resistance (IHVR) contribute to development of portal hypertension (PHT) and cirrhosis. More importantly, immunosuppressive tumor microenvironment (TME), which is closely related to the crosstalk between LSECs and immune liver cells like CD8+ T cells, promotes advances tumorigenesis, especially HCC. However, the connections within the crosstalk between LSECs and other liver cells during the progression from liver fibrosis to cirrhosis to HCC have yet to be discussed. In this review, we first summarize the current knowledge of how different crosstalk between LSECs and other liver cells, including hepatocytes, hepatic stellate cells (HSCs), macrophoges, immune cells in liver and extra cellular matrix (ECM) contribute to the physiological function and the progrssion from liver fibrosis to cirrhosis, or even to HCC. Then we examine current treatment strategies for LSECs crosstalk in liver fibrosis, cirrhosis and HCC.

Expression of ICAM-1 in Blood Vascular Endothelium and Tissues in Human Premalignant Lesion and Gastric/Hepatocellular Carcinomas

Background/Aims

Angiogenesis is essential for the outgrowth and metastasis of tumors. The structure and characteristics of tumor vasculature differ from those of normal vessels. We compared the characteristics of differentially expressed genes in endothelial cells (ECs) isolated from gastric and normal cells.

Methods

Previously, we had isolated pure tumor ECs (TECs) and normal ECs (NECs) from advanced gastric cancer (AGC) lesions and normal mucosal tissues, respectively. Using the oligomer chip platform of the Affymetrix GeneChip technology, genes that were expressed more than three-fold with a significance of p≤0.001 were measured. The intercellular adhesion molecule 1 (ICAM-1) was found to be overexpressed in the TECs compared to the normal gastric ECs. In this study, the upregulation of ICAM-1 was confirmed in cultured TECs by immunofluorescence.

Results

The expression of ICAM-1 was upregulated in the ECs, as well as in the stromal and immune cells, in early human gastric preneoplastic and hepatic fibrotic tissues. Upregulation of ICAM-1 was observed in the TECs, immune cells, and cancer epithelial cells in AGC and hepatocellular carcinoma (HCC). These results suggest that increased ICAM-1 expression in the ECs of the tissue microenvironment progressively contributes to the recruitment of immune cells to promote inflammation, leading to fibrosis and tumorigenesis.

Conclusions

Therefore, upregulated ICAM-1 in the tissues in premalignant gastric diseases or hepatic fibrosis and their malignant cancers could be a promising target for disease prevention and treatment.

Techniques and Algorithms for Hepatic Vessel Skeletonization in Medical Images: A Survey

Hepatic vessel skeletonization serves as an important means of hepatic vascular analysis and vessel segmentation. This paper presents a survey of techniques and algorithms for hepatic vessel skeletonization in medical images. We summarized the latest developments and classical approaches in this field. These methods are classified into five categories according to their methodological characteristics. The overview and brief assessment of each category are provided in the corresponding chapters, respectively. We provide a comprehensive summary among the cited publications, image modalities and datasets from various aspects, which hope to reveal the pros and cons of every method, summarize its achievements and discuss the challenges and future trends.

Multiscale reconstruction of various vessels in the intact murine liver lobe

The liver contains a variety of vessels and participates in miscellaneous physiological functions. While past studies generally focused on certain hepatic vessels, we simultaneously obtained all the vessels and cytoarchitectural information of the intact mouse liver lobe at single-cell resolution. Here, taking structural discrepancies of various vessels into account, we reconstruct and visualize the portal vein, hepatic vein, hepatic artery, intrahepatic bile duct, intrahepatic lymph of an intact liver lobe and peribiliary plexus in its selected local areas, providing a technology roadmap for studying the fine hepatic vascular structures and their spatial relationship, which will help research into liver diseases and evaluation of medical efficacies in the future.

Use of the volume-averaged Murray's deviation method for the characterization of branching geometry in liver fibrosis: a preliminary study on vascular circulation

Background

Vascular changes in liver fibrosis can result in increased intrahepatic vascular resistance and impaired blood circulation. This can hinder the recovery from fibrosis and may eventually lead to portal hypertension, a major cirrhosis complication. This report proposed a volume-averaged Murray's deviation method to characterize intrahepatic circulation in the liver during fibrosis and its subsequent regression via X-ray phase-contrast computed tomography (PCCT).

Methods

Liver fibrosis was induced in 24 Sprague-Dawley rats by exposure to carbon tetrachloride (CCl₄) for up to 10 weeks, after which, spontaneous regression commenced and continued until week 30. High-resolution three-dimensional (3D) imaging of the livers was performed with PCCT. The values of Murray's deviation based on the volume-averaged and the conventional diameter-based methods were compared. After that, the intrahepatic circulation at different stages of fibrosis was evaluated using the volume-averaged method. The increase in collagen during liver fibrosis was assessed by pathological analyses.

Results

A comparison of the 2 methods showed that with an increase in the number of diameter measurements, the value of Murrary's deviation obtained using the diameter-based method gradually approaches those of the volume-averaged method, with minimal variations. The value of Murray's deviation increased with the development of fibrosis. After reversal, the value rapidly decreased and approached that of the normal state in both the main branches (1.05±0.17, 1.17±0.21, 1.34±0.18, and 1.17±0.19 in the normal, moderate, severe, and regressive groups, respectively; P<0.05 between the severe group and other groups) and the small branches (1.05±0.09, 1.42±0.48, 1.79±0.57, and 1.18±0.28 in the normal, moderate, severe, and regressive group, respectively; P<0.05 between adjacent groups). An analysis of Murray's deviation and the pathological results showed that the vascular circulation in this disease model was consistent with the progression and recovery from fibrosis.

Conclusions

This study showed the validity of the volume-averaged method for calculating Murray's deviation and demonstrated that it could accurately evaluate the blood circulation state of the liver during fibrosis and its subsequent regression. Thus, the volume-averaged method of calculating Murray's deviation may be an objective and valuable staging criterion to evaluate intrahepatic circulation during liver fibrosis.

DYNAMICS OF FIBROTIC CHANGES IN THE LIVER AFTER THE SUCCESSFUL ERADICATION OF HEPATITIS C VIRUS IN PATIENTS WITH NAFLD

OBJECTIVE

The aim: To assess the dynamics of serum levels of angiopoietin-2 and transforming growth factor-β1 in patients with chronic hepatitis C (CHC) with concomitant nonalcoholic fatty liver disease (NAFLD) after successful DAAs.

PATIENTS AND METHODS

Materials and methods: 82 patients with CHC were examined, of which 56 were diagnosed with NAFLD and increased body weight. Ang-2, TGF-β1, leptin, adiponectin, and the degree of liver fibrosis were determined for all participants. The patients were divided into groups: 1 gr. (n=23) - CHС + increased body weight + hepatic steatosis, 2 gr. (n=33) - СНС + increased body weight + nonalcoholic steatohepatitis, 3rd gr. (n=26) - CHC. All patients received DAAs for 12 weeks.

RESULTS

Results: From 82 patients F3-4 had 31 people, F1-2 - 25, F0-1 - 11, F0 -15 patients. F3-4 and steatosis S2-3 (p<0.05) was more common in patients of 2 gr.. Serum Ang-2 levels were higher (p<0.05) in patients of 2 gr. with F3-4, than in patients with F0-2. Fibrosis regression occurred more often in patients with 1 and 3 gr. with F1-2 than in patients 2 gr. and F3-4 and was accompanied by a decrease in Ang-2 and TGF-β1 levels.

CONCLUSION

Conclusions: High levels of Ang-2 and TGF-β1 are registered in patients with CHC+NAFLD, which correlate with the degree of liver fibrosis and significantly decrease after successful DAAs in patients with low initial stages of liver fibrosis and normal body weight.

Limitations and Possibilities of Transarterial Chemotherapeutic Treatment of Hepatocellular Carcinoma

Because diagnostic tools for discriminating between hepatocellular carcinoma (HCC) and advanced cirrhosis are poor, HCC is often detected in a stage where transarterial chemoembolization (TACE) is the best treatment option, even though it provides a poor survival gain. Despite having been used worldwide for several decades, TACE still has many limitations. First, there is a vast heterogeneity in the cellular composition and metabolism of HCCs as well as in the patient population, which renders it difficult to identify patients who would benefit from TACE. Often the delivered drug does not penetrate sufficiently selectively and deeply into the tumour and the drug delivery system is not releasing the drug at an optimal clinical rate. In addition, therapeutic effectiveness is limited by the crosstalk between the tumour cells and components of the cirrhotic tumour microenvironment. To improve this widely used treatment of one of our most common and deadly cancers, we need to better understand the complex interactions between drug delivery, local pharmacology, tumour targeting mechanisms, liver pathophysiology, patient and tumour heterogeneity, and resistance mechanisms. This review provides a novel and important overview of clinical data and discusses the role of the tumour microenvironment and lymphatic system in the cirrhotic liver, its potential response to TACE, and current and possible novel DDSs for locoregional treatment.

Significance of circulating tumor cells in the portal vein regarding metastases and vascular invasion in hepatocellular carcinoma patients

BACKGROUND

Vascular invasion is an important risk factor of poor prognosis in hepatocellular carcinoma (HCC) patients. The detection of circulating tumor cells (CTCs) in the blood is direct evidence of tumor presence. There are few reports on CTCs and metastasis and vascular invasion of HCC. The purpose of this study was to analyze the significance of CTCs in the portal vein regarding metastases and vascular invasion in HCC patients.

METHODS

A total of 104 HCC patients diagnosed and treated in Zhengzhou University People's Hospital were enrolled. Surgery was performed in 60 individuals. Portal vein blood samples were collected before treatment for CTCs detection. We used the isolation by size of epithelial tumor cells (ISET) and fluorescence in situ hybridization (FISH) to enrich and classify CTCs from blood samples. The patients were divided into metastasis and nonmetastasis groups according to the metastasis status before treatment. Differences in clinical indicators such as alpha-fetoprotein (AFP) levels, tumor size, CTCs count, and macrovascular tumor thrombus between the two groups were analyzed as well as the associations of CTCs count with the above indicators. For individuals with postoperative pathology, the relationship between CTCs counts and microvascular invasion (MVI) was analyzed.

RESULTS

The amounts of portal vein CTCs were higher in patients with metastases compared with the nonmetastases group (20 vs. 7; z=3.795; P<0.001). Multivariate logistic regression analysis showed that the CTC count was a risk factor for HCC metastasis [odds ratio (OR) =1.044; 95% CI: 1.011-1.079]. The sensitivity and specificity of CTC count in predicting HCC metastasis were 82.93% and 52.38%, respectively. CTC count was significantly correlated with tumor size (rs=0.308; P=0.001), vascular invasion (z=4.211; P<0.001), and MVI (z=12.763; P=0.002). A threshold CTC count of seven showed the most significant power for predicting metastasis.

CONCLUSIONS

Vascular invasion positivity was closely related to HCC metastasis. Portal vein CTC count before treatment was correlated with vascular invasion and could be considered one of the factors affecting HCC metastasis. However, the ability of CTC count was limited in predicting HCC metastasis due to insufficient specificity.

Amygdalin Ameliorates Liver Fibrosis through Inhibiting Activation of TGF-β/Smad Signaling

OBJECTIVE

To observe the effect of amygdalin on liver fibrosis in a liver fibrosis mouse model, and the underlying mechanisms were partly dissected in vivo and in vitro.

METHODS

Thirty-two male mice were randomly divided into 4 groups, including control, model, low- and high-dose amygdalin-treated groups, 8 mice in each group. Except the control group, mice in the other groups were injected intraperitoneally with 10% carbon tetrachloride (CCl₄)-olive oil solution 3 times a week for 6 weeks to induce liver fibrosis. At the first 3 weeks, amygdalin (1.35 and 2.7 mg/kg body weight) were administered by gavage once a day. Mice in the control group received equal quantities of subcutaneous olive oil and intragastric water from the fourth week. At the end of 6 weeks, liver tissue samples were harvested to detect the content of hydroxyproline (Hyp). Hematoxylin and eosin and Sirius red staining were used to observe the inflammation and fibrosis of liver tissue. The expressions of collagen I (Col-I), alpha-smooth muscle actin (α-SMA), CD31 and transforming growth factor β (TGF-β)/Smad signaling pathway were observed by immunohistochemistry, quantitative real-time polymerase chain reaction and Western blot, respectively. The activation models of hepatic stellate cells, JS-1 and LX-2 cells induced by TGF-β1 were used in vitro with or without different concentrations of amygdalin (0.1, 1, 10 µmol/L). LSECs. The effect of different concentrations of amygdalin on the expressions of liver sinusoidal endothelial cells (LSECs) dedifferentiation markers CD31 and CD44 were observed.

RESULTS

High-dose of amygdalin significantly reduced the Hyp content and percentage of collagen positive area, and decreased the mRNA and protein expressions of Col-I, α-SMA, CD31 and p-Smad2/3 in liver tissues of mice compared to the model group (P<0.01). Amygdalin down-regulated the expressions of Col-I and α-SMA in JS-1 and LX-2 cells, and TGFβ R1, TGFβ R2 and p-Smad2/3 in LX-2 cells compared to the model group (P<0.05 or P<0.01). Moreover, 1 and 10 µmol/L amygdalin inhibited the mRNA and protein expressions of CD31 in LSECs and increased CD44 expression compared to the model group (P<0.05 or P<0.01).

CONCLUSIONS

Amygdalin can dramatically alleviate liver fibrosis induced by CCl₄ in mice and inhibit TGF-β/Smad signaling pathway, consequently suppressing HSCs activation and LSECs dedifferentiation to improve angiogenesis.

Gene Signatures Detect Damaged Liver Sinusoidal Endothelial Cells in Chronic Liver Diseases

Liver sinusoidal endothelial cells have a gatekeeper function in liver homeostasis by permitting substrates from the bloodstream into the space of Disse and regulating hepatic stellate cell activation status. Maintenance of LSEC's highly specialized phenotype is crucial for liver homeostasis. During liver fibrosis and cirrhosis, LSEC phenotype and functions are lost by processes known as capillarization and LSEC dysfunction. LSEC capillarization can be demonstrated by the loss of fenestrae (cytoplasmic pores) and the manifestation of a basement membrane. Currently, no protein or genetic markers can clearly distinguish healthy from damaged LSECs in acute or chronic liver disease. Single cell (sc)RNA sequencing efforts have identified several LSEC populations in mouse models for liver disease and in human cirrhotic livers. Still, there are no clearly defined genesets that can identify LSECs or dysfunctional LSEC populations in transcriptome data. Here, we developed genesets that are enriched in healthy and damaged LSECs which correlated very strongly with healthy and early stage- vs. advanced human liver diseases. A damaged LSEC signature comprised of Fabp4/5 and Vwf/a1 was established which could efficiently identify damaged endothelial cells in single cell RNAseq data sets. In LSECs from an acute CCl₄ liver injury mouse model, Fabp4/5 and Vwf/a1 expression is induced within 1-3 days while in cirrhotic human livers these 4 genes are highly enriched in damaged LSECs. In conclusion, our newly developed gene signature of damaged LSECs can be applicable to a wide range of liver disease etiologies, implicating a common transcriptional alteration mechanism in LSEC damage.