Combined treatment with dipeptidyl peptidase-4 inhibitor (sitagliptin) and angiotensin-II type 1 receptor blocker (losartan) suppresses progression in a non-diabetic rat model of steatohepatitis

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.

Regulatory network and interplay of hepatokines, stellakines, myokines and adipokines in nonalcoholic fatty liver diseases and nonalcoholic steatohepatitis

Fatty liver disease is a spectrum of liver pathologies ranging from simple hepatic steatosis to non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), and culminating with the development of cirrhosis or hepatocellular carcinoma (HCC). The pathogenesis of NAFLD is complex and diverse, and there is a lack of effective treatment measures. In this review, we address hepatokines identified in the pathogenesis of NAFLD and NASH, including the signaling of FXR/RXR, PPARα/RXRα, adipogenesis, hepatic stellate cell activation/liver fibrosis, AMPK/NF-κB, and type 2 diabetes. We also highlight the interaction between hepatokines, and cytokines or peptides secreted from muscle (myokines), adipose tissue (adipokines), and hepatic stellate cells (stellakines) in response to certain nutritional and physical activity. Cytokines exert autocrine, paracrine, or endocrine effects on the pathogenesis of NAFLD and NASH. Characterizing signaling pathways and crosstalk amongst muscle, adipose tissue, hepatic stellate cells and other liver cells will enhance our understanding of interorgan communication and potentially serve to accelerate the development of treatments for NAFLD and NASH.

Does DPP-IV Inhibition Offer New Avenues for Therapeutic Intervention in Malignant Disease?

Simple Summary

There is growing interest in identifying the effects of antidiabetic agents on cancer risk, progression, and anti-cancer treatment due to the long-term use of these medications and the inherently increased risk of malignancies in diabetic patients. Tumor development and progression are affected by multiple mediators in the tumor microenvironment, several of which may be proteolytically modified by the multifunctional protease dipeptidyl peptidase-IV (DPP-IV, CD26). Currently, low-molecular-weight DPP-IV inhibitors (gliptins) are used in patients with type 2 diabetes based on the observation that DPP-IV inhibition enhances insulin secretion by increasing the bioavailability of incretins. However, the DPP-IV-mediated cleavage of other biopeptides and chemokines is also prevented by gliptins. The potential utility of gliptins in other areas of medicine, including cancer, is therefore being evaluated. Here, we critically review the existing evidence on the role of DPP-IV inhibitors in cancer pathogenesis, their potential to be used in anti-cancer treatment, and the possible perils associated with this approach.

Abstract

Dipeptidyl peptidase IV (DPP-IV, CD26) is frequently dysregulated in cancer and plays an important role in regulating multiple bioactive peptides with the potential to influence cancer progression and the recruitment of immune cells. Therefore, it represents a potential contributing factor to cancer pathogenesis and an attractive therapeutic target. Specific DPP-IV inhibitors (gliptins) are currently used in patients with type 2 diabetes mellitus to promote insulin secretion by prolonging the activity of the incretins glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Nevertheless, the modulation of the bioavailability and function of other DPP-IV substrates, including chemokines, raises the possibility that the use of these orally administered drugs with favorable side-effect profiles might be extended beyond the treatment of hyperglycemia. In this review, we critically examine the possible utilization of DPP-IV inhibition in cancer prevention and various aspects of cancer treatment and discuss the potential perils associated with the inhibition of DPP-IV in cancer. The current literature is summarized regarding the possible chemopreventive and cytotoxic effects of gliptins and their potential utility in modulating the anti-tumor immune response, enhancing hematopoietic stem cell transplantation, preventing acute graft-versus-host disease, and alleviating the side-effects of conventional anti-tumor treatments.

Antiangiogenic Drugs in NASH: Evidence of a Possible New Therapeutic Approach

Non-alcoholic fatty liver disease is the most common liver disorder worldwide, and its progressive form non-alcoholic steatohepatitis (NASH) is a growing cause of liver cirrhosis and hepatocellular carcinoma (HCC). Lifestyle changes, which are capable of improving the prognosis, are hard to achieve, whereas a pharmacologic therapy able to combine efficacy and safety is still lacking. Looking at the pathophysiology of various liver diseases, such as NASH, fibrosis, cirrhosis, and HCC, the process of angiogenesis is a key mechanism influencing the disease progression. The relationship between the worsening of chronic liver disease and angiogenesis may suggest a possible use of drugs with antiangiogenic activity as a tool to stop or slow the progression of the disorder. In this review, we highlight the available preclinical data supporting a role of known antiangiogenic drugs (e.g., sorafenib), or phytotherapeutic compounds with multiple mechanism of actions, including also antiangiogenic activities (e.g., berberine), in the treatment of NASH.

Effective Combination Therapy of Angiotensin-II Receptor Blocker and Rifaximin for Hepatic Fibrosis in Rat Model of Nonalcoholic Steatohepatitis

The progression of nonalcoholic steatohepatitis (NASH) is complicated. The multiple parallel-hits theory is advocated, which includes adipocytokines, insulin resistance, endotoxins, and oxidative stress. Pathways involving the gut–liver axis also mediate the progression of NASH. Angiotensin-II receptor blockers (ARB) suppress hepatic fibrosis via the activation of hepatic stellate cells (HSCs). Rifaximin, a nonabsorbable antibacterial agent, is used for the treatment of hepatic encephalopathy and has been recently reported to improve intestinal permeability. We examined the inhibitory effects on and mechanism of hepatic fibrogenesis by combining ARB and rifaximin administration. Fischer 344 rats were fed a choline-deficient/l-amino acid-defined (CDAA) diet for 8 weeks to generate the NASH model. The therapeutic effect of combining an ARB and rifaximin was evaluated along with hepatic fibrogenesis, the lipopolysaccharide–Toll-like receptor 4 (TLR4) regulatory cascade, and intestinal barrier function. ARBs had a potent inhibitory effect on hepatic fibrogenesis by suppressing HSC activation and hepatic expression of transforming growth factor-β and TLR4. Rifaximin reduced intestinal permeability by rescuing zonula occludens-1 (ZO-1) disruption induced by the CDAA diet and reduced portal endotoxin. Rifaximin directly affect to ZO-1 expression on intestinal epithelial cells. The combination of an ARB and rifaximin showed a stronger inhibitory effect compared to that conferred by a single agent. ARBs improve hepatic fibrosis by inhibiting HSCs, whereas rifaximin improves hepatic fibrosis by improving intestinal permeability through improving intestinal tight junction proteins (ZO-1). Therefore, the combination of ARBs and rifaximin may be a promising therapy for NASH fibrosis.

Comparison of serum fibrosis biomarkers for diagnosing significant liver fibrosis in patients with chronic hepatitis B

Chronic hepatitis B (CHB) virus continues to be a leading cause of morbidity and mortality worldwide. The diagnosis of liver fibrosis has a key role in selecting patients with CHB for antiviral treatment. However, serum biomarkers demonstrate limited diagnostic utility. The present study aimed to compare the performances of fibrosis biomarkers for diagnosing significant liver fibrosis that indicates the need for antiviral therapy in patients with CHB and to identify the most appropriate biomarker for these patients. The current study included 96 antiviral-naïve patients with CHB who underwent liver biopsy. METAVIR scoring system was used to assess liver fibrosis and necroinflammation. The diagnostic performances were evaluated of the platelet (PLT) count; the levels of hyaluronan, serum 7S domain of type 4 collagen, procollagen type III N-terminal peptide, tissue inhibitor of metalloproteinases 1, Mac-2 binding protein glycosylation isomer (M2BPGi) and N-terminal type III collagen propeptide (Pro-C3); the fibrosis index based on four factors; the aspartate aminotransferase-to-platelet ratio index; and enhanced liver fibrosis score for identifying significant liver fibrosis [≥fibrosis stage 2 (F2)]. All fibrosis biomarkers, except the Pro-C3 level, correlated with the fibrosis stage. M2BPGi was better than other biomarkers for diagnosing ≥F2, with the highest area under the curve of 0.902. M2BPGi demonstrated a higher diagnostic accuracy for significant fibrosis than mild/severe fibrosis or cirrhosis. However, no significant correlation was observed between the M2BPGi level and fibrosis stage in patients with CHB having significant liver necroinflammation defined as ≥ necroinflammatory activity 2. The M2BPGi level and PLT count were exclusively correlated with the fibrosis stage in 73 patients without significant liver necroinflammation. M2BPGi demonstrated the highest diagnostic performance for significant fibrosis in patients having significant liver fibrosis with no significant liver necroinflammation. In conclusion, the M2BPGi level can accurately diagnose significant liver fibrosis that indicates the need for antiviral therapy in patients with CHB.

Combined Treatment with Sodium-Glucose Cotransporter-2 Inhibitor (Canagliflozin) and Dipeptidyl Peptidase-4 Inhibitor (Teneligliptin) Alleviates NASH Progression in A Non-Diabetic Rat Model of Steatohepatitis

Hepatocellular carcinoma (HCC) is the strongest independent predictor of mortality in non-alcoholic steatohepatitis (NASH)-related cirrhosis. The effects and mechanisms of combination of sodium-dependent glucose cotransporter inhibitor and canagliflozin (CA) and dipeptidyl peptidase-4 inhibitor and teneligliptin (TE) on non-diabetic NASH progression were examined. CA and TE suppressed choline-deficient, L-amino acid-defined diet-induced hepatic fibrogenesis and carcinogenesis. CA alone or with TE significantly decreased proinflammatory cytokine expression. CA and TE significantly attenuated hepatic lipid peroxidation. In vitro studies showed that TE alone or with CA inhibited cell proliferation and TGF-β1 and α1 (I)-procollagen mRNA expression in Ac-HSCs. CA+TE inhibited liver fibrogenesis by attenuating hepatic lipid peroxidation and inflammation and by inhibiting Ac-HSC proliferation with concomitant attenuation of hepatic lipid peroxidation. Moreover, CA+TE suppressed in vivo angiogenesis and oxidative DNA damage. CA or CA+TE inhibited HCC cells and human umbilical vein endothelial cell (HUVEC) proliferation. CA+TE suppressed vascular endothelial growth factor expression and promoted increased E-cadherin expression in HUVECs. CA+TE potentially exerts synergistic effects on hepatocarcinogenesis prevention by suppressing HCC cell proliferation and angiogenesis and concomitantly reducing oxidative stress and by inhibiting angiogenesis with attenuation of oxidative stress. CA+TE showed chemopreventive effects on NASH progression compared with single agent in non-diabetic rat model of NASH, concurrent with Ac-HSC and HCC cell proliferation, angiogenesis oxidative stress, and inflammation. Both agents are widely, safely used in clinical practice; combined treatment may represent a potential strategy against NASH.

Combined effect of a farnesoid X receptor agonist and dipeptidyl peptidase-4 inhibitor on hepatic fibrosis

AIM

Non-alcoholic steatohepatitis (NASH) has a broad clinicopathological spectrum (inflammation to severe fibrosis). The farnesoid X receptor agonist obeticholic acid (OCA) ameliorates the histological features of NASH; satisfactory antifibrotic effects have not yet been reported. Here, we investigated the combined effects of OCA + a dipeptidyl peptidase-4 inhibitor (sitagliptin) on hepatic fibrogenesis in a rat model of NASH.

METHODS

Fifty Fischer 344 rats were fed a choline-deficient L-amino-acid-defined (CDAA) diet for 12 weeks. The in vitro and in vivo effects of OCA + sitagliptin were assessed along with hepatic fibrogenesis, lipopolysaccharide-Toll-like receptor 4 (TLR4) regulatory cascade and intestinal barrier function. Direct inhibitory effects of OCA + sitagliptin on activated hepatic stellate cells (Ac-HSCs) were assessed in vitro.

RESULTS

Treatment with OCA + sitagliptin potentially inhibited hepatic fibrogenesis along with Ac-HSC proliferation and hepatic transforming growth factor (TGF)-β1, α1(I)-procollagen, and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA expression and hydroxyproline levels. Obeticholic acid inhibited hepatic TLR4 expression and increased hepatic matrix metalloproteinase-2 expression. Obeticholic acid decreased intestinal permeability by ameliorating CDAA diet-induced zonula occludens-1 disruption, whereas sitagliptin directly inhibited Ac-HSC proliferation. The in vitro suppressive effects of OCA + sitagliptin on TGF-β1 and α1(I)-procollagen mRNA expression and p38 phosphorylation in Ac-HSCs were almost consistent. Sitagliptin directly inhibited the regulation of Ac-HSC.

CONCLUSIONS

Treatment with OCA + sitagliptin synergistically affected hepatic fibrogenesis by counteracting endotoxemia induced by intestinal barrier dysfunction and suppressing Ac-HSC proliferation. Thus, OCA + sitagliptin could be a promising therapeutic strategy for NASH.

TGR5 Activation Modulates an Inhibitory Effect on Liver Fibrosis Development Mediated by Anagliptin in Diabetic Rats

Hyperglycemia and hyperinsulinemia activate the proliferative potential of hepatic stellate cells (HSCs) and promote hepatic fibrosis. Dipeptidyl peptidase-4 (DPP-4) inhibitors, antidiabetic agents, reportedly inhibit the HSC proliferation. Additionally, Takeda G protein-coupled receptor 5 (TGR5) agonists induce the systemic release of glucagon-like peptides from intestinal L cells, which maintains glycemic homeostasis. This study assessed the combined effect of TGR5 agonist and DPP-4 inhibitor on diabetes-based liver fibrosis development. Male diabetic rats received intraperitoneal injection of porcine serum (PS) to induce liver fibrosis, and they were orally administered the following agents: oleanolic acid (OA) as a TGR5 agonist, anagliptin (ANA) as a DPP-4 inhibitor, and a combination of both agents. Treatment with OA or ANA significantly improved glycemic status and attenuated intrahepatic steatosis and lipid peroxidation in diabetic rats. PS-induced liver fibrosis development was also drastically suppressed by treatment with either agent, and the combination of both reciprocally enhanced the antifibrotic effect. Fecal microbiome demonstrated that both agents inhibited the increase in the Firmicutes/Bacteroidetes ratio, an indicator of dysbiosis related to metabolic syndromes. Furthermore, ANA directly inhibited in vitro HSC proliferative and profibrogenic activities. Collectively, TGR5 agonist and DPP-4 inhibitor appears to be a novel strategy against liver fibrosis under diabetic conditions.

Inhibition of Heme Oxygenase Antioxidant Activity Exacerbates Hepatic Steatosis and Fibrosis In Vitro

The progression of non-alcoholic fatty liver disease (NAFLD) and the development of hepatic fibrosis is caused by changes in redox balance, leading to an increase of reactive oxygen species (ROS) levels. NAFLD patients are at risk of progressing to non-alcoholic steatohepatitis (NASH), associated to cardiovascular diseases (CVD), coronary heart disease and stroke. Heme Oxygenase-1 (HO-1) is a potent endogenous antioxidant gene that plays a key role in decreasing oxidative stress. The present work was directed to determine whether use of an inhibitor of HO-1 activity affects lipid metabolism and fibrosis process in hepatic cells. Oil Red assay and mRNA analysis were used to evaluate the triglycerides content and the lipid metabolism pathway in HepG2 cells. ROS measurement, RT-PCR and Soluble collagen assay were used to assess the intracellular oxidant, the fibrosis pathway and the soluble collagen in LX2 cells. The activity of HO-1 was inhibited using Tin Mesoporphyrin IX (SnMP). Our study demonstrates that a non-functional HO system results in an increased lipid storage and collagen release in hepatocytes. Consequently, an increase of HO-1 levels may provide a therapeutic approach to address the metabolic alterations associated with NAFLD and its progression to NASH.

Exogenous Administration of Low-Dose Lipopolysaccharide Potentiates Liver Fibrosis in a Choline-Deficient l-Amino-Acid-Defined Diet-Induced Murine Steatohepatitis Model

Various rodent models have been proposed for basic research; however, the pathogenesis of human nonalcoholic steatohepatitis (NASH) is difficult to closely mimic. Lipopolysaccharide (LPS) has been reported to play a pivotal role in fibrosis development during NASH progression via activation of toll-like receptor 4 (TLR4) signaling. This study aimed to clarify the impact of low-dose LPS challenge on NASH pathological progression and to establish a novel murine NASH model. C57BL/6J mice were fed a choline-deficient l-amino-acid-defined (CDAA) diet to induce NASH, and low-dose LPS (0.5 mg/kg) was intraperitoneally injected thrice a week. CDAA-fed mice showed hepatic CD14 overexpression, and low-dose LPS challenge enhanced TLR4/NF-κB signaling activation in the liver of CDAA-fed mice. LPS challenge potentiated CDAA-diet-mediated insulin resistance, hepatic steatosis with upregulated lipogenic genes, and F4/80-positive macrophage infiltration with increased proinflammatory cytokines. It is noteworthy that LPS administration extensively boosted pericellular fibrosis with the activation of hepatic stellate cells in CDAA-fed mice. Exogenous LPS administration exacerbated pericellular fibrosis in CDAA-mediated steatohepatitis in mice. These findings suggest a key role for LPS/TLR4 signaling in NASH progression, and the authors therefore propose this as a suitable model to mimic human NASH.

Alogliptin alleviates liver fibrosis via suppression of activated hepatic stellate cell

Liver fibrosis occurs in most types of chronic liver diseases. The understanding of the pathogenesis of liver fibrosis has grown considerably, but the effective treatments are still lacking. Alogliptin, a classical Dipeptidyl peptidase-4 (DPP4) inhibitor with great effects on type 2 diabetes, has shown the potential to protect liver, but its effects on the progression of liver fibrosis have not been clarified. Herein, we explored the anti-fibrosis effects of alogliptin. In vitro, we demonstrated that alogliptin suppressed the activation of LX-2 upon transforming growth factor-β (TGF-β) challenge. In vivo, chronic treatment with alogliptin alleviated hepatic steatosis and protected from the liver injury in ob/ob mice, which delayed the progression of liver fibrosis. Furthermore, alogliptin significantly relieved the hepatic fibrosis in CCl4-induced liver fibrosis mouse model. In conclusion, our results demonstrate that negatively modulation of alogliptin on hepatic stellate cell (HSC) activation might contribute to liver fibrosis alleviation. Our research provides the potential possibility of alogliptin on the application for liver fibrosis therapy and suggests that DPP4 may be a novel target for liver fibrosis therapy.

Proton pump inhibitor therapy does not increase serum endotoxin activity in patients with cirrhosis

AIM

Proton pump inhibitors (PPIs) are frequently prescribed in patients with cirrhosis, but this therapy entails potential complications. We aimed to investigate the influence of PPI use on intestinal permeability in patients with cirrhosis.

METHODS

We recruited 228 patients with cirrhosis and divided them into four groups. Group (Gp)1 comprised patients receiving a PPI with concurrent neomycin (NEO) (PPI-NEO group, n = 14 [6.1%]), Gp2 and Gp3 comprised those receiving either PPI or NEO (PPI group, n = 91 [39.9%]; and NEO group, n = 11 [4.4%]), and Gp4 comprised those receiving neither of these medications (control group; n = 112 [49.1%]). We assessed the intestinal permeability by measuring endotoxin activity (EA) using a luminol chemiluminescence method.

RESULTS

Endotoxin activity levels were significantly higher in patients with Child B cirrhosis than in those with Child A cirrhosis, but we found no significant differences in EA levels between patients with Child C cirrhosis and those with either Child A or B cirrhosis. We observed no significant differences in EA levels among groups 1-4. Patients without antibiotic exposure (n = 203), comprising 91 patients on PPI therapy (Gp2) and 112 no-PPI-therapy controls (Gp4), were subdivided according to Child-Pugh (CP) classification. We found no significant differences in EA levels between Gp2 and Gp4 in either CP class.

CONCLUSION

Our results suggest that PPI usage does not have a significant impact on serum levels of gut-derived endotoxins, which are already elevated because of the increased intestinal permeability in patients with cirrhosis.

In vivo Assessment of Combined Effects of Glibenclamide and Losartan in Diabetic Rats

OBJECTIVE

Diabetic complications involve multiple pathological pathways, including hyperglycemia-induced oxidative stress and inflammation. Combination therapy is usually employed to improve treatment outcomes and to lower potential adverse effects. In this study, we evaluated the effects of antidiabetic and antihypertensive agents, glibenclamide (GLI) and losartan (LT), on diabetes mellitus (DM)-associated metabolic changes in rats.

MATERIALS AND METHODS

Streptozotocin-induced diabetic animals were orally treated with GLI 5 mg/kg and/or LT 25 mg/kg for 4 weeks. Blood glucose, insulin, aspartate aminotransferase, alanine aminotransferase, urinary creatinine, and urea levels were measured. Serum, liver, and kidney values of inflammatory markers, such as interleukin-1β, tumor necrosis factor alpha, and interleukin-6 were assessed, along with lipid peroxidation products (e.g., thiobarbituric acid reactive substances), endogenous antioxidants (e.g., glutathione), as well as antioxidant enzyme activities (e.g., catalase, superoxide dismutase, and glutathione peroxidase). Finally, histological changes in liver and kidney tissues were evaluated.

RESULTS

DM markedly induced systemic, hepatic, and renal inflammation and lowered antioxidant defense mechanisms. Treatment of diabetic rats with either GLI or LT significantly improved liver and kidney functions and histological structure. Moreover, both medications reduced signs of oxidative stress and inflammation in blood, liver, and kidney samples. Combining GLI and LT showed similar protective potential against systemic, hepatic, and renal oxidative stress and inflammation.

CONCLUSION

Adding LT to GLI therapy revealed prospective antioxidant and anti-inflammatory action, while no synergistic or additive effects were observed.

Effects of dipeptidyl peptidase-4 inhibitors on transforming growth factor-β1 signal transduction pathways in the ovarian fibrosis of polycystic ovary syndrome rats

Aim

Examine the effects of dipeptidyl peptidase‐4 (DPP4) inhibitor Sitagliptin on the transforming growth factor‐β1 (TGF‐β1) signal transduction pathway in polycystic ovary syndrome (PCOS) rats with ovarian fibrosis.

Methods

Thirty rats were divided randomly into the PCOS model group, Sitagliptin treatment group and blank control group. Dehydroepiandrosterone was administered to the model group and treatment group to establish the models. Then, the phenotype of rats was recorded, and the serum sex hormone levels were measured. The pathological structures of the rat ovaries were observed. The protein and mRNA expression levels of DPP4, connective tissue growth factor (CTGF), TGF‐β1 and Smad2/3 in the ovaries were analyzed.

Results

There was no statistically difference in fasting body weight and blood glucose among the three groups before Sitagliptin treatment (P > 0.05). The fasting blood glucose level was significantly decreased after the administration of Sitagliptin (P < 0.05). The level of testosterone in the model group was reduced remarkably after Sitagliptin treatment (P < 0.001). The protein expression levels of DPP4, CTGF and TGF‐β1 in the ovarian stroma were lower in the treatment group than in the model group (P < 0.01, P < 0.001, P < 0.05). The mRNA levels of DPP4, CTGF and TGF‐β1 in the model group also greatly declined after Sitagliptin treatment (P < 0.05, P < 0.001, P < 0.01).

Conclusion

The DPP4 inhibitor Sitagliptin lowers fasting blood glucose, relieves the high androgen state of PCOS rats and delays the process of ovarian fibrosis, which may be related to reducing the levels of factors related to the TGF‐β1/Smad2/3 signaling pathway.

Development of NASH in Obese Mice is Confounded by Adipose Tissue Increase in Inflammatory NOV and Oxidative Stress

AIM

Nonalcoholic steatohepatitis (NASH) is the consequence of insulin resistance, fatty acid accumulation, oxidative stress, and lipotoxicity. We hypothesize that an increase in the inflammatory adipokine NOV decreases antioxidant Heme Oxygenase 1 (HO-1) levels in adipose and hepatic tissue, resulting in the development of NASH in obese mice.

METHODS

Mice were fed a high fat diet (HFD) and obese animals were administered an HO-1 inducer with or without an inhibitor of HO activity to examine levels of adipose-derived NOV and possible links between increased synthesis of inflammatory adipokines and hepatic pathology.

RESULTS

NASH mice displayed decreased HO-1 levels and HO activity, increased levels of hepatic heme, NOV, MMP2, hepcidin, and increased NAS scores and hepatic fibrosis. Increased HO-1 levels are associated with a decrease in NOV, improved hepatic NAS score, ameliorated fibrosis, and increases in mitochondrial integrity and insulin receptor phosphorylation. Adipose tissue function is disrupted in obesity as evidenced by an increase in proinflammatory molecules such as NOV and a decrease in adiponectin. Importantly, increased HO-1 levels are associated with a decrease of NOV, increased adiponectin levels, and increased levels of thermogenic and mitochondrial signaling associated genes in adipose tissue.

CONCLUSIONS

These results suggest that the metabolic abnormalities in NASH are driven by decreased levels of hepatic HO-1 that is associated with an increase in the adipose-derived proinflammatory adipokine NOV in our obese mouse model of NASH. Concurrently, induction of HO-1 provides protection against insulin resistance as seen by increased insulin receptor phosphorylation. Pharmacological increases in HO-1 associated with decreases in NOV may offer a potential therapeutic approach in preventing fibrosis, mitochondrial dysfunction, and the development of NASH.

Renin-angiotensin system inhibition ameliorates CCl4-induced liver fibrosis in mice through the inactivation of nuclear transcription factor kappa B

Therapeutic interventions for liver fibrosis are still limited due to the complicated molecular pathogenesis. Renin-angiotensin system (RAS) seems to contribute to the development of hepatic fibrosis. Therefore, we aimed to examine the effect of RAS inhibition on CCl₄-induced liver fibrosis. Mice were treated with silymarin (30 mg·kg^-1), perindopril (1 mg·kg^-1), fosinopril (2 mg·kg^-1), or losartan (10 mg·kg^-1). The administration of RAS inhibitors improved liver histology and decreased protein expression of alpha smooth muscle actin (α-SMA) and hepatic content of hydroxyproline. These effects found to be mediated via inactivation of nuclear transcription factor kappa B (NFκB) pathway by the inhibition of NFκB p65 phosphorylation at the Ser536 residue and phosphorylation-induced degradation of nuclear factor kappa-B inhibitor alpha (NFκBia) subsequently inhibited NFκB-induced TNF-α and TGF-β1, leading to lower levels of tissue inhibitor of metalloproteinase-1 (TIMP-1) and vascular endothelial growth factor (VEGF). We concluded that the tissue affinity of the angiotensin converting enzyme inhibitors (ACEIs) has no impact on its antifibrotic activity and that interfering the RAS either through the inhibition of ACE or the blockade of AT1R has the same therapeutic benefit. These results suggest RAS inhibitors as promising candidates for further clinical trials in the management of hepatic fibrosis.

Sodium glucose cotransporter 2 inhibitor canagliflozin attenuates liver cancer cell growth and angiogenic activity by inhibiting glucose uptake

Sodium-glucose cotransporter 2 inhibitors (SGLT2-Is) comprise a new class of antidiabetic agents that inhibit glucose reabsorption in the renal proximal tubules. Although a recent report demonstrated the potential ability of SGLT2-Is to attenuate cancer growth of SGLT2-expressing cancer cells, little is known about the effects of SGLT2-Is on hepatocellular carcinoma (HCC). Here, we investigate the anti-cancer properties of a SGLT2-I, canagliflozin, against human liver cancer cells. SGTL2 mRNA and protein expression were detected in Huh7 and HepG2 cells, although not in HLE as well as primary human hepatocytes and hepatic stellate cells. Canagliflozin exerted antiproliferative effects on SGLT2-expressing Huh7 and HepG2 cells in a dose-dependent manner by inhibiting glycolytic metabolism including glucose uptake, lactate and intracellular ATP production. This agent also induced G2/M arrest and apoptosis with inhibited phosphorylation of ERK, p38 and AKT and cleavage of caspase3. Xenograft tumor growth assay showed that oral administration of canagliflozin (10 mg/kg/day) significantly reduced subcutaneous tumor burdens in a glycemic status-independent manner, and attenuated intratumor vascularization in Huh7- and HepG2-derived xenograft tumors in BALB/c nude mice. In vitro, canagliflozin suppressed the increased human umbilical vein endothelial cell (HUVEC) proliferation and tubular formation which were observed in Huh7 or HepG2 co-cultures. By contrast, canagliflozin had no effect on tumor growth and intratumor angiogenesis in SGLT2-null HLE-derived xenograft models. These results indicate that SGLT2-I therapy is a potential new strategy for the treatment of HCC.

Serum angiotensin-converting enzyme level for evaluating significant fibrosis in chronic hepatitis B

AIM

To evaluate the diagnostic performance of angiotensin-converting enzyme (ACE) on significant liver fibrosis in patients with chronic hepatitis B (CHB).

METHODS

In total, 100 patients with CHB who underwent liver biopsy in our hospital were enrolled, and 70 patients except for 30 patients with hypertension, fatty liver or habitual alcoholic consumption were analyzed. We compared histological liver fibrosis and serum ACE levels and evaluated the predictive potential to diagnose significant liver fibrosis by comparison with several biochemical marker-based indexes such as the aspartate aminotransferase (AST)-to-platelet ratio index (APRI), the fibrosis index based on four factors (FIB-4), the Mac-2 binding protein glycosylation isomer (M2BPGi) level and the number of platelets (Plt).

RESULTS

Serum ACE levels showed moderately positive correlation with liver fibrotic stages (R² = 0.181). Patients with significant, advanced fibrosis and cirrhosis (F2-4) had significantly higher serum ACE levels than those with early-stage fibrosis and cirrhosis (F0-1). For significant fibrosis (≥ F2), the 12.8 U/L cut-off value of ACE showed 91.7% sensitivity and 75.0% specificity. The receiver-operating characteristic (ROC) curves analysis revealed that the area under the curve (AUC) value of ACE was 0.871, which was higher than that of APRI, FIB-4, M2BPGi and Plt.

CONCLUSION

The serum ACE level could be a novel noninvasive, easy, accurate, and inexpensive marker of significant fibrosis stage in patients with CHB.