Common Bile Duct Ligation Rats Research Articles

#694 Effects of nonsteroidal mineralocorticoid receptor antagonists on kidney of cirrhotic rats

Abstract Background and Aims Aldosterone binds to renal mineralocorticoid receptors (MRs) to regulate fluid and electrolytes homeostasis. In addition, aldosterone can be deleterious as a driver of inflammation and tissue fibrosis in several organs. Thus, blockade of aldosterone represents an important option to mitigate the target-organ damage. Mineralocorticoid receptor antagonists (MRAs) have been widely used as diuretic drugs for the management of hypertension, cirrhosis, and heart failure. However, the use of MRAs is limited by adverse events such as hyperkalemia. More recently, novel nonsteroidal selective MRAs with improved safety profiles have been developed. This nonsteroidal MRA (finerenone) has higher selectivity and stronger affinity for the MR, leading to lower risk of hyperkalemia. Recent evidences showed that finerenone reduces albuminuria, risk of CKD progression, and cardiovascular events in patients with chronic kidney disease and type 2 diabetes with a low incidence of hyperkalemia related treatment discontinuation. The pathophysiology of cirrhosis is very similar to that of cardiac failure. Decompensated cirrhosis is frequently treated with the MRAs. In addition to fluid management, MRAs showed hepatoprotective actions via reducing oxidative stress and inflammatory responses in CCl4-induced and common bile duct ligation (CBDL)-induced liver injury models. The potential beneficial effects of nonsteroidal MRA on cirrhosis had never been studied. This study aims to explore the renal protective role of nonsteroidal selective MRA and associated mechanisms in common bile duct ligation-related liver injury in rat model. Method CBDL was used to create liver injury in the Male Sprague-Dawley Drats. Finerenone (10 mg/kg/day) or vehicle was administered since the 1st day after CBDL. The effects of nonsteroidal selective MRA on kidneys were surveyed in two paralleled series on the 7th day (inflammation) and the 28th day (cirrhosis), respectively. The following parameters were evaluated: (a) hemodynamic parameters; (b) serum potassium, liver and renal function; (c) in-situ kidney perfusion; (d) western analyses of renal cortex and medulla. Results Compared with the vehicle-treated group, there was significantly lower renal vascular responsiveness to ET-1 in CBDL rats receiving 28 days of MRA (p<0.05) (Fig. 1B), but not in those receiving 7 days of MRA (Fig. 1A). MRA treatment led to no significant change in mean arterial pressure, portal pressure, serum potassium, liver, and renal function in CBDL rats (Table 1). The expressions of vasoactive mediators, such as iNOS, eNOS, ETA, and ETB in both renal cortex and medulla showed no significant change in CBDL rats following 28 days of MRA treatment (Fig. 2). Conclusion MRA treatment led to no significant effects on hemodynamics, liver, and renal function, but lower renal vascular responsiveness to ET-1 in CBDL rats receiving 28 days of MRA. The exact mechanisms remained to be further studied.

Reduced Cx43 Expression Induces Autophagy through Activation of the AMPK-mTOR-ULK1 Signaling Pathway in the Common Bile Duct Ligation Rat Heart.

This study aimed to investigate the relationship between Cx43 expression and autophagy mediated by the AMPK-mTOR-Ulk1 signaling pathway in jaundice heart. In this study, a jaundice model was established in common bile duct ligation (CBDL) rats. Cardiac injury was assessed using various methods including myocardial injury indicators, echocardiography, TEM, HE staining, Masson staining, IHC, and IF. We investigated the regulatory relationship between Cx43, autophagy, and the AMPK-mTOR-ULK pathway in vivo by administering autophagy agonists (Rapa), autophagy inhibitors (3-MA), and Cx43 inhibitors (Gap 26). In vitro, we observed the relationship between autophagy and the AMPK-mTOR-ULK1 pathway in cells by exposing them to the AMPK inhibitor Compound C and the AMPK activator AICAR. We found that CBDL induced autophagy through the AMPK-mTOR-ULK pathway, leading to the inhibition of myocardial dysfunction. Rapamycin pretreatment with CBDL3d exhibited a protective effect against myocardial injury and promoted autophagy. In contrast, 3-MA had no impact. Pretreatment with rapamycin at CBDL2w enhanced autophagy and aggravated cardiac injury; however, inhibition of autophagy using 3-MA attenuated cardiac injury. Cell viability was enhanced by AMPK inhibitors and inhibited by AMPK agonists. In addition, we observed that increased autophagy led to decreased Cx43 expression, which negatively affected cardiac function. CBDL induces myocardial injury in rats and activates autophagy through the AMPK-mTOR-ULK pathway, resulting in decreased Cx43 protein levels. A moderate increase in early autophagy in CBDL can improve cardiac injury, while late inhibition of autophagy can reduce myocardial injury.

Tea polyphenols and Levofloxacin alleviate the lung injury of hepatopulmonary syndrome in common bile duct ligation rats through Endotoxin -TNF signaling

Background & AimsHepatopulmonary syndrome (HPS) is characterized by pulmonary vasodilation and arterial blood oxygen desaturation in patients with chronic liver disease. Generally, common bile duct ligation (CBDL) rats are a suitable experimental model for studying hepatopulmonary syndrome. Our previous study demonstrated that endotoxin surges markedly, followed by bacterial translocation and the loss of liver immune function in all the stages of CBDL, thereby contributing to the pathogenesis of HPS. However, the mechanisms behind the increase of the endotoxin and how to alleviate it have not yet been elucidated. Pulmonary injury induced by increased bilirubin, endotoxin, and inflammatory mediators occurs in the early and later stages of CBDL. This study assessed the effects of Tea polyphenols (TP) and Levofloxacin on endotoxin reduction and suppression of lung injury in HPS rats in the long and short term, respectively. MethodsMorphological change of pulmonary injury, HPS relative index, endotoxin concentration, and the activation extent of Malondialdehyde (MDA) and Myeloperoxidase (MPO) were evaluated in CBDL rats with or without TP and Levofloxacin for three weeks or six weeks. The inflammation factors of serum, lung tissue, and BALF were then compared at the same condition for the two time periods. This was followed by adoption of the network pharmacology approach, which was mainly composed of active component gathering, target prediction, HPS gene collection, network analysis, and gene enrichment analysis. Finally, the mRNA and protein levels of the inflammatory factors were studied and relative signaling expression was assessed using RT-PCR and Western blot analysis. ResultsThe obtained results indicated that the pulmonary injury manifestation was perceived and endotoxin, MDA, and MPO activation were markedly increased in the early and later stages of CBDL. TP and Levofloxacin treatment alleviated endotoxin infection and inflammation factor expression three weeks and six weeks after CBDL. In addition, Levofloxacin displayed a short time anti-bacterial effect, while TP exerted a long period function. TP and Levofloxacin also reduced TNF-α, TGF-β, IL-1β, PDGF-BB, NO, ICAM-1, and ET-1 expression on the mRNA or protein expression. With regard to the pharmacological mechanism, the network analysis indicated that 12 targets might be the therapeutic targets of TP and Levofloxacin on HPS, namely ET-1, NOs3, VEGFa, CCl2, TNF, Ptgs2, Hmox1, Alb, Ace, Cav1, and Mmp9. The gene enrichment analysis implied that TP and Levofloxacin probably benefited patients with HPS by modulating pathways associated with the AGE-RAGE signaling pathway, the TNF signaling pathway, the HIF-1 signaling pathway, the VEGF signaling pathway, and the IL-17 signaling pathway, Rheumatoid arthritis, Fluid shear stress, and atherosclerosis. Finally, the TNF-α level was mainly diminished on the protein level following CBDL. ConclusionsTP and Levofloxacin could alleviate pulmonary injury for short and long period, respectively, while at the same time preventing endotoxin and the development of HPS in CBDL rats. These effects are possibly associated with the regulation of the Endotoxin -TNF-α pathways.

Gan Shen Fu Fang ameliorates liver fibrosis in vitro and in vivo by inhibiting the inflammatory response and extracellular signal-regulated kinase phosphorylation.

BACKGROUNDLiver fibrosis is a common health problem worldwide and there is still a lack of effective medicines. The Chinese herbal medicine, Gan Shen Fu Fang (GSFF) is composed of salvianolic acid B and diammonium glycyrrhizinate. In this study, we observed the effects of GSFF on liver fibrosis in vivo and in vitro in an attempt to provide some hope for the treatment.AIMTo observe the effects of GSFF on liver fibrosis in vivo and in vitro and investigate the mechanism from the perspective of the inflammatory response and extracellular signal-regulated kinase (ERK) phosphorylation.METHODSCommon bile duct-ligated rats were used for in vivo experiments. Hepatic stellate cells-T6 (HSC-T6) cells were used for in vitro experiments. Hematoxylin and eosin staining and Masson staining, biochemical assays, hydroxyproline (Hyp) assays, enzyme-linked immunoasorbent assay and western blotting were performed to evaluate the degree of liver fibrosis, liver function, the inflammatory response and ERK phosphorylation. The CCK8 assay, immunofluorescence and western blotting were applied to test the effect of GSFF on HSC-T6 cell activation and determine whether GSFF had an effect on ERK phosphorylation in HSC-T6 cells.RESULTSGSFF improved liver function and inhibited liver fibrosis in common bile duct-ligated rats after 3 wk of treatment, as demonstrated by histological changes, hydroxyproline assays and collagen I concentrations. GSFF alleviated inflammatory cell infiltration and reduced the synthesis of pro-inflammatory cytokines [tumor necrosis factor-α (TNF-α) and interlukin-1β] and NF-κB. In addition, GSFF decreased ERK phosphorylation. In vitro, GSFF inhibited the viability of HSC-T6 cells with and without transforming growth factor β1 (TGF-β1) stimulation and decreased the synthesis of collagen I. GSFF had the greatest effect at a concentration of 0.5 μmol/L. GSFF inhibited the expression of α-smooth muscle actin (α-SMA), a marker of HSC activation, in HSC-T6 cells. Consistent with the in vivo results, GSFF also inhibited the phosphorylation of ERK and downregulated the expression of NF-κB.CONCLUSIONGSFF inhibited liver fibrosis progression in vivo and HSC-T6 cell activation in vitro. These effects may be related to an alleviated inflammatory response and downregulated ERK phosphorylation.

P0545DPP-4 INHIBITOR ATTENUATED RENAL VASOCONSTRICTION FOLLOWING ISCHEMIA-REPERFUSION INJURY IN CIRRHOTIC RATS

Abstract Background and Aims Cirrhotic patients may develop gastroesophageal varices to cope with portal hypertension. Annual risk of variceal bleeding among small and large varices is 5% and 15%, respectively. Bleeding from varices is a medical emergency and is associated with a high morbidity and mortality. In those who survive the initial bleeding event, the risks of further bleeding and other serious complications remain high, such as hypotension and ischemia-reperfusion injury. Ischemia-reperfusion injury is a leading cause of acute kidney injury. In patients with advanced liver cirrhosis, variceal bleeding associated hypotension and ischemia-reperfusion injury may activated endogenous vasoconstrictors, leading to severe renal vasoconstriction and subsequent renal failure (so called hepatorenal syndrome). There was not effective treatment yet. Dipeptidyl peptidase-4 (DPP-4) inhibitors, a new class of oral hypoglycemic agents, have shown potential pleiotropic effects, such as anti-inflammatory and anti-oxidant properties. Previous studies reported that inhibition of DPP-4 could attenuate the development of ischemia-reperfusion injury in kidney. Cumulated evidences indicates that DPP-4 inhibitors could attenuate the endothelin-1 induced contraction and increase endothelial-dependent vasodilation related to activation of endothelial nitric oxide synthase and increased production of nitric oxide. In addition, DPP-4 inhibitors may suppress inflammation and fibrosis in the kidneys independently of glycemic control. The aim of this study is to delineate the effect of DPP-4 inhibitors in renal vascular reactivity of cirrhotic rats following ischemia-reperfusion injury. Method Male Sprague-Dawley rats weighing 240-270 g were used for experiments. Secondary biliary cirrhosis were created by common bile duct ligation (CBDL). Rats receiving sham surgery (SHAM) were used as the control group. Linagliptin (3 mg/kg/day) or distilled water (DW) was administered via oral gavage since the 1st day throughout the 28th day after surgery. On the 29th day, all rats were randomized to control group or ischemia-reperfusion injury. Bilateral renal pedicles of rats in the ischemia-reperfusion injury group were clamped for 45 minutes with microvascular clamps. Thereafter, the clamps were removed and reperfusion was allowed by visual control. After 60 minutes of reperfusion period, kidneys were perfused in situ via right renal artery for continuous monitoring of renal perfusion pressure using a non-recirculating system. Results There was no significant difference in mean arterial pressure, heart rate, and portal pressure between DW and DPP-4 inhibitor treated groups in both SHAM and CBDL rats. Ischemia-reperfusion injury enhanced renal vascular reactivity to endothelin-1 in both SHAM (p = 0.027) and CBDL (p = 0.016) rats, implying renal vasoconstriction. Compared with corresponding DW-treated rats, DPP-4 inhibitor treatment abrogated renal hyper-reactivity following ischemia-reperfusion injury in BDL rats (p = 0.038), but not in SHAM rats (p = 0.17). Conclusion We concluded that DPP-4 inhibitors may attenuate the development of renal vasoconstriction following ischemia-reperfusion injury in cirrhotic rats. The potentially mechanisms remained to be elucidated.

A high-dose rapamycin treatment alleviates hepatopulmonary syndrome in cirrhotic rats.

Rapamycin is a type of immunosuppressive agent that acts through inhibition of mammalian target of rapamycin (mTOR). Hepatopulmonary syndrome (HPS) is a lethal complication in cirrhotic patients. It is characterized by hypoxia and increased intrapulmonary shunts, in which pulmonary inflammation and angiogenesis play important roles. The current study aimed to evaluate the effect of rapamycin on HPS using the experimental model of common bile duct ligation (CBDL)-induced cirrhosis in rats. The rats received low-dose (0.5 mg/kg), high-dose (2 mg/kg) rapamycin, or vehicle from the 15th to the 28th day post CBDL. Then the mortality rate, hemodynamics, biochemistry parameters, arterial blood gas and plasma levels of vascular endothelial growth factor (VEGF) and tumor necrosis factor (TNF)-α were evaluated on the 28th day post CBDL. Pulmonary histopathological stains were performed, and protein expression was examined. In parallel groups, the intrapulmonary shunts of CBDL rats were measured. Compared with the control, a high-dose rapamycin treatment decreased portal pressure and improved hypoxia in CBDL rats. It also reduced the plasma level of VEGF and TNF-α and decreased intrapulmonary shunts. Meanwhile, it ameliorated pulmonary inflammation and angiogenesis and downregulated the protein expression of mTOR, P70S6K, nuclear factor kappa B (NFκB), VEGF, and VEGF receptor 2. In contrast, low-dose rapamycin did not attenuate intrapulmonary shunts despite ameliorating portal hypertension. High-dose rapamycin ameliorates HPS in cirrhotic rats as evidenced by the alleviated hypoxia and decreased intrapulmonary shunts. Downregulation of the mTOR/P70S6K, NFκB, and VEGF signaling pathways might play a key role.

Loss of cell polarity regulated by PTEN/Cdc42 enrolled in the process of Hepatopulmonary Syndrome.

One central factor in hepatopulmonary syndrome (HPS) pathogenesis is pulmonary vascular remodelling (PVR) which involves dysregulation of proliferation and migration in pulmonary microvascular endothelial cells (PMVECs). Growing evidence suggests that Apical/basolateral polarity plays an important role in cell proliferation, migration, adhesion and differentiation. In this study, we explored whether cell polarity is involved and critical in experimental HPS rats that are induced by common bile duct ligation (CBDL). Cell polarity related proteins were analysed in CBDL rats lung and PMVECs under the HPS serum stimulation by immunofluorescence assay. Cdc42/PTEN activity, cell proliferation and migration and Annexin A2 (AX2) in PMVECs were determined, respectively. Cell polarity related proteins, lost their specialized luminal localization in PMVECs of the CBDL rat. The loss of cell polarity was induced by abnormal activity of Cdc42, which was strongly enhanced by the interaction between p‐PTEN and Annexin A2 in PMVECs, after treatment with serum from CBDL rats. It led to over‐proliferation and high migration ability of PMVECs. Down‐regulation of PTEN‐Cdc42 activity in PMVECs restored cell polarity and thus reduced their ability of migration and proliferation. Our study suggested that the loss of cell polarity plays a critical role in the pathogenesis of HPS‐associated PVR and may become a potentially effective therapeutic target.

Folic acid ameliorates homocysteine-induced angiogenesis and portosystemic collaterals in cirrhotic rats

Introduction and ObjectivesLiver cirrhosis is characterized by increased intrahepatic resistance, splanchnic vasodilation/angiogenesis, and formation of portosystemic collateral vessels. Collaterals can cause lethal complications such as gastroesophageal variceal hemorrhage. Homocysteine is linked to vascular dysfunction and angiogenesis and higher levels have been reported in cirrhotic patients. It is also known that folic acid supplementation reverses the effects of homocysteine. However, the treatment effect in cirrhosis has yet to be investigated. Material and methodsLiver cirrhosis was induced in Sprague-Dawley rats with common bile duct ligation (CBDL). The CBDL rats randomly received (1) vehicle; (2) dl-homocysteine thiolactone (1g/kg/day); (3) dl-homocysteine thiolactone plus folic acid (100mg/kg/day); or (4) folic acid. On the 29th day, hemodynamic parameters, liver and renal biochemistry, protein expressions of proangiogenic factors, mesenteric vascular density and portosystemic shunting were evaluated. ResultsIn the cirrhotic rats, homocysteine increased mesenteric vascular density and the severity of shunting. It also up-regulated the protein expressions of mesenteric vascular endothelial growth factor (VEGF) and phosphorylated-endothelial nitric oxide synthase (p-eNOS). These effects were reversed by folic acid treatment (P<0.05). ConclusionFolic acid ameliorated the adverse effects of homocysteine in the cirrhotic rats, which may be related to down-regulation of the VEGF-NO signaling pathway.

Effects of Caffeine Treatment on Hepatopulmonary Syndrome in Biliary Cirrhotic Rats.

Hepatopulmonary syndrome (HPS) is a lethal complication of cirrhosis characterized by hypoxia and overt intrapulmonary shunting. In this study, we investigated the effect of caffeine in rats with common bile duct ligation (CBDL)-induced liver cirrhosis and HPS. CBDL rats were randomly allocated to receive caffeine or vehicle for 14 days. On the 28th day after CBDL, mortality rate, hemodynamics, liver, and renal biochemistry parameters and arterial blood gas analysis were evaluated. Lung and liver were dissected for the evaluation of inflammation, angiogenesis and protein expressions. In another series with parallel groups, the intrapulmonary shunting was determined. Caffeine significantly reduced portal pressure (caffeine vs. control: 10.0 ± 3.7 vs. 17.0 ± 8.1 mmHg, p < 0.05) in CBDL rats. The mortality rate, mean arterial pressure, biochemistry data and hypoxia were similar between caffeine-treated and control groups. Caffeine alleviated liver fibrosis and intrahepatic angiogenesis but intrapulmonary inflammation and angiogenesis were not ameliorated. The hepatic VEGF/Rho-A protein expressions were down-regulated but the pulmonary inflammation- and angiogenesis-related protein expressions were not significantly altered by caffeine. Caffeine did not reduce the intrapulmonary shunting, either. Caffeine has been shown to significantly improve liver fibrosis, intrahepatic angiogenesis and portal hypertension in cirrhotic rats, however, it does not ameliorate HPS.

Mesenchymal stem cells suppress hepatic fibrosis accompanied by expanded intrahepatic natural killer cells in rat fibrosis model.

Natural killer (NK) cells have antifibrotic effects. We have evaluated the influence of rat bone marrow-mesenchymal stem cell (BM-MSC) treatment on liver histology, biochemical liver function tests, systemic immunoregulatory state and NK cell distribution in liver and peripheral blood in rat model of common bile duct (CBD) ligation and compared the results with the control group. Rats were divided into three groups: (1) CBD ligated (CBDL) rats received phosphate-buffered saline (CBDL + PBS group) or (2) MSC (CBDL + MSC group) and sham-operated rats received MSC (healthy + MSC group). We found significantly decreased fibrosis scores with BM-MSC treatment in CBDL rats compared to the control (CBDL + PBS) group while no fibrosis developed in sham operated (healthy + MSC) group. BM-MSC treatment has decreased the inflammation as reflected by the significantly decreased T cell proliferation and inflammatory cytokine concentrations from splenocyte culture and liver tissue itself compared to CBDL + PBS. NK cells both in parenchyme and portal areas decreased significantly in liver and blood in CBDL + PBS compared to healthy + MSC while they were found to be increased in CBDL + MSC compared to CBDL + PBS rats. In conclusion, BM-MSCs may suppress hepatic fibrosis accompanied by expanded intrahepatic NK cells in CBDL rats. Thus, our animal study shows that MSC treatment holds great promise for treatment of patients with end-stage liver diseases through a possible mechanism by adopting the NK cell population and new studies investigating the role of NK cells and clinical fibrosis are warranted.Trial registration number: Marmara University Animal Care and Use Committee approval code: 73.2013.mar.

Endotoxemia-enhanced renal vascular reactivity to endothelin-1 in cirrhotic rats.

Hepatorenal syndrome (HRS), a severe complication of advanced cirrhosis, is defined as hypoperfusion of kidneys resulting from intense renal vasoconstriction in response to generalized systemic arterial vasodilatation. Nevertheless, the mechanisms have been barely investigated. Cumulative studies demonstrated renal vasodilatation in portal hypertensive and compensated cirrhotic rats. Previously, we identified that blunted renal vascular reactivity of portal hypertensive rats was reversed after lipopolysaccharide (LPS). This study was therefore conducted to delineate the sequence of renal vascular alternation and underlying mechanisms in LPS-treated cirrhotic rats. Sprague-Dawley rats were randomly allocated to receive sham surgery (Sham) or common bile duct ligation (CBDL). LPS was induced on the 28th day after surgery. Kidney perfusion was performed at 0.5 or 3 h after LPS to evaluate renal vascular response to endothelin-1 (ET-1). Endotoxemia increased serum ET-1 levels ( P < 0.0001) and renal arterial blood flow ( P < 0.05) in both Sham and CBDL rats. CBDL rats showed enhanced renal vascular reactivity to ET-1 at 3 h after LPS ( P = 0.026). Pretreatment with endothelin receptor type A (ETA) antagonist abrogated the LPS-enhanced renal vascular response in CBDL rats ( P < 0.001). There were significantly lower inducible nitric oxide synthase (iNOS) expression but higher ETA and phosphorylated extracellular signal-regulated kinase (p-ERK) expressions in renal medulla of endotoxemic CBDL rats ( P < 0.05). We concluded that LPS-induced renal iNOS inhibition, ETA upregulation, and subsequent ERK signaling activation may participate in renal vascular hyperreactivity in cirrhosis. ET-1-targeted therapy may be feasible in the control of HRS. NEW & NOTEWORTHY Hepatorenal syndrome (HRS) occurred in advanced cirrhosis after large-volume paracentesis or bacterial peritonitis. We demonstrated that intraperitoneal lipopolysaccharide (LPS) enhanced renal vascular reactivity to endothelin-1 (ET-1) in cirrhotic rats, accompanied by inducible nitric oxide synthase inhibition, endothelin receptor type A (ETA) upregulation, and subsequent extracellular signal-regulated kinase activation in renal medulla. Pretreatment with ETA antagonist abrogated the LPS-enhanced renal vascular response in common bile duct ligation rats. These findings suggest that further clinical investigation of ET-1-targeted therapy may be feasible in the control of HRS.

Effect of sirolimus on liver cirrhosis and hepatic encephalopathy of common bile duct-ligated rats

Cirrhosis is often associated with portal hypertension and portal-systemic collateral vessels formation attributed to angiogenesis, which leads to severe complications as hepatic encephalopathy. Sirolimus has anti-fibrosis and anti-angiogenesis effects, but whether it influences the severity of portal-systemic collaterals and hepatic encephalopathy is unknown. This study was thus designed to address this issue in rats with common bile duct ligation-induced liver cirrhosis. Sham-operated rats were surgical controls. Rats were intraperitoneally administered with 0.5 and 2 mg/kg/day sirolimus or vehicle for 2 weeks. Four weeks post operations, motor activities, body weight, biochemistry and hemodynamic data were measured. The liver was dissected for histopathology, immunohistochemical stains and protein analysis. On the parallel cirrhotic groups, the portal-systemic shunting was determined. The results showed that the body weight gain was significantly lower in sirolimus-treated rats. Sirolimus reduced portal pressure and plasma levels of alanine aminotransferase, aspartate aminotransferase and ammonia, and attenuated hepatic inflammation and fibrosis in cirrhotic rats. In addition, the hepatic phosphorylated mammalian target of rapamycin (mTOR) and P70S6K protein expressions were significantly downregulated and endothelial nitric oxide synthase (eNOS) expression upregulated by sirolimus. Sirolimus did not influence portal-systemic shunting and motor activities of cirrhotic rats. In conclusion, sirolimus significantly improved hepatic inflammation and fibrosis accompanied by portal pressure reduction in cirrhotic rats, in which down-regulated mTOR/P70S6K and up-regulated eNOS expressions might play a role. However, sirolimus did not significantly change the severity of portal-systemic collaterals and motor activities, suggesting that the multifactorial pathogenesis of hepatic encephalopathy could not be fully overcome by sirolimus.

The beneficial effects of curcumin in cirrhotic rats with portal hypertension.

In liver cirrhosis with portal hypertension, the uneven distribution of vasoactive substances leads to increased intrahepatic vascular resistance and splanchnic vasodilatation. Angiogenesis also induces increased portal inflow and portosystemic collaterals. The collaterals may induce lethal complications such as gastroesophageal variceal hemorrhage, but the therapeutic effect of vasoconstrictors is still suboptimal due to poor collateral vasoresponsivenss. Curcumin has aroused much attention for its antifibrosis, vasoactive, and anti-angiogenesis actions. However, whether it affects the aforementioned aspects is unknown. Liver cirrhosis was induced by common bile duct ligation (CBDL) in Sprague–Dawley rats. Sham-operated rats were controls. CBDL and sham rats were randomly allocated to receive curcumin (600 mg/kg per day) or vehicle since the 15th day after BDL. On the 29th day, portal hypertension related parameters were surveyed. Portosystemic collateral in situ perfusion was performed to evaluate vascular activity. Chronic curcumin treatment decreased portal pressure (PP), cardiac index (CI) and increased systemic vascular resistance (SVR) in cirrhotic rats. In splanchnic system, curcumin decreased superior mesenteric artery (SMA) flow and increased SMA resistance. Mesenteric angiogenesis was attenuated by curcumin. Acute administration of curcumin significantly induced splanchnic vasoconstriction. The mesenteric protein expressions of p-endothelial nitric oxide synthase (eNOS), cyclooxygenase (COX) 2 (COX2), vascular endothelial growth factor (VEGF), p-VEGF receptor 2 (VEGFR2), and p-Erk were down-regulated. In collateral system, curcumin decreased portosystemic shunting and induced vasoconstriction. In conclusion, chronic curcumin administration in cirrhotic rats ameliorated portal hypertension related hemodynamic derangements and portosystemic collaterals. Curcumin also attenuated splanchnic hyperdynamic circulation by inducing vasoconstriction through inhibition of eNOS activation and by decreasing mesenteric angiogenesis via VEGF pathway blockade.

AMD3100 treatment attenuates pulmonary angiogenesis by reducing the c-kit (+) cells and its pro-angiogenic activity in CBDL rat lungs

Recent studies have shown that pulmonary angiogenesis is an important pathological process in the development of hepatopulmonary syndrome (HPS), and growing evidence has indicated that Stromal cell-derived factor 1/C-X-C chemokine receptor type 4 (SDF-1/CXCR4) axis is involved in pulmonary vascular disease by mediating the accumulation of c-kit+ cells. This study aimed to test the effect of AMD3100, an antagonist of CXCR4, in HPS pulmonary angiogenesis. Common bile duct ligation (CBDL) rats were used as experimental HPS model and were treated with AMD3100 (1.25mg/kg/day, i.p.) or 0.9% saline for 3weeks. The sham rats underwent common bile duct exposure without ligation. The c-kit+ cells accounts and its angiogenic-related functions, prosurvival signals, pulmonary angiogenesis and arterial oxygenation were analysed in these groups. Our results showed that pulmonary SDF-1/CXCR4, Akt, Erk and VEGF/VEGFR2 were significantly activated in CBDL rats, and the numbers of circulating and pulmonary c-kit+ cells were increased in CBDL rats compared with control rats. Additionally, the angiogenic-related functions of c-kit+ cells and pulmonary microvessel counts were also elevated in CBDL rats. CXCR4 inhibition reduced pulmonary c-kit+ cells and microvessel counts and improved arterial oxygenation within 3weeks in CBDL rats. The pulmonary prosurvival signals and pro-angiogenic activity of c-kit+ cells were also down-regulated in AMD3100-treated rats. In conclusion, AMD3100 treatment attenuated pulmonary angiogenesis in CBDL rats and prevented the development of HPS via reductions in pulmonary c-kit+ cells and inhibition of the prosurvival signals. Our study provides new insights in HPS treatment.

Mesenchymal Stem Cells in Rat Hepatic Fibrosis MModel: Benefits? Mechanism of Action?: 2017 Presidential Poster Award

Introduction: Hepatic fibrosis may evolve to liver cirrhosis which may ultimately develop into hepatocellular carcinoma. Mesenchymal stem cells (MSCs) have potential to trans-differentiate into hepatic cells and thus may be a curative option in liver cirrhosis. Natural killer (NK) cells are a component of the innate immune system that destroy compromised host cells and have critical antifibrotic role. Aim: To show the effects of bone marrow MSCs transferred via the tail vein to the rats having hepatic fibrosis produced by common bile duct ligation (CBDL) with a special focus on the changes of the NK population distribution. Methods: Rats were divided into three groups; 1- CBDL rats that were injected with phosphate-buffered saline (PBS), 2- CBDL rats injected with MSCs, 3- healthy rats that were sham operated and given MSCs. All rats were sacrificed at the end of the experiment. We analyzed the in vivo functional outcomes by measuring the serum glucose, bilirubin and ALT levels. Splenocytes isolated from the collected spleens were cultured and the supernatants were analyzed for IL (interleukin)-1α, TNF (tumor necrosis factor)-α, IFN (interferon)-γ and IL-10 using flow cytometry. Results: Liver fibrosis developed in CBDL rats while the healthy rats did not show any alteration in liver architecture. Although healthy group had significantly lower serum bilirubin, ALT and glucose levels than CBDL rats, the difference regarding those parameters did not differ between groups 1 and 2. T-lymphocyte proliferation was significantly suppressed in group 2 compared to group 1. IL-1α, TNF-α and IFN-γ levels in supernatants of cultured lymphocytes in group 2 were significantly higher than group 3 while they tended to be lower than group 1. NK and Treg cells in peripheral blood significantly increased in group 2 compared to group 1. Histologically, hepatic fibrosis scores were significantly alleviated in group 2 compared to group 1 (p=0.039). NK cells in the general hepatic parenchyma and in the portal areas were both increased significantly in group 2 compared to group 1. Conclusion: Our findings suggest bone marrow derived MSCs may be beneficial in alleviating the hepatic fibrosis by suppressing the T cell proliferation and the proinflammatory cytokines and inducing NK cell recruitment to liver parenchyma in rats. Thus, MSC treatment may appear promising in liver injury and future clinical therapies are warranted. Immunophenotyping of leukocytes. CD3+CD4+ T lymphocyte, CD3+CD8+ Cytotoxic T cell, CD4+CD25+ T regulatory cell and CD161a NK cell in all groups by flow cytometry. (B) CD3+CD4+ % T lymphocyte, CD3+CD8+ % Cytotoxic T cell, CD4+CD25+ %T regulatory cell and CD161a NK cells were displayed statistically in all groups..*P < 0.05, **P < 0.01.Figure

The protective effect of Gan Shen Fu Fang on liver endothelial cells in common bile duct-ligated rats

Objective: To elucidate the protective effect of Gan Shen Fu Fang (GSFF) on liver endothelial cells in common bile duct-ligated (CBDL) rats. Materials and Methods: Cirrhosis was induced by common bile duct ligation. The rats were divided into three groups: sham group, CBDL group, and GSFF group. After 2 weeks of ligation, rats in the GSFF group were administered GSFF. After 4 weeks, the hydroxyproline (Hyp) content of liver tissues was spectrophotometrically determined. The histological changes were evaluated by H and E and Masson staining. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to observe the ultrastructural changes in the liver, especially in the liver sinusoidal endothelial cells (LSECs). Results: Hyp synthesis was significantly inhibited by GSFF, which agreed with the results from H and E and Masson staining for liver fibrosis. The TEM observations of CBDL rats revealed reduced hepatocyte microvilli and deposited fibrous tissue underneath LSECs. SEM confirmed the TEM findings and showed that the fenestrae of LSECs decreased and even disappeared in CBDL rats. The morphological results indicated hepatic sinusoid capillarization. GSFF promoted the restoration of fenestrae and reversed hepatic sinusoid capillarization. Conclusion: GSFF can inhibit Hyp synthesis, restore the fenestrae of LSECs, and reverse hepatic sinusoid capillarization in CBDL rats. These results provide a basis for future detailed investigations of the mechanism of action of GSFF in LSECs.

CXCR2 is involved in pulmonary intravascular macrophage accumulation and angiogenesis in a rat model of hepatopulmonary syndrome.

Hepatopulmonary syndrome (HPS) is a lung complication in various liver diseases, with high incidence, poor prognosis and no effective non-surgical treatments in patients with hepatocirrhosis. Therefore, assessing HPS pathogenesis to explore proper therapy strategies is clinically relevant. In the present study, male Sprague-Dawley rats underwent sham operation or common bile duct ligation (CBDL). Two weeks post-surgery, the following groups were set up for 2weeks of treatment: sham + normal saline, CBDL + CXCR2 antagonist SB225002, CBDL + tumour necrosis factor α (TNF-α) antagonist PTX and CBDL + normal saline groups. Liver and lung tissues were collected after mean arterial pressure (MAP) and portal venous pressure (PVP) measurements. Haematoxylin and eosin (H&E) staining (lung) and Masson staining (liver) were performed for pathological analyses. Finally, pulmonary tissue RNA and total protein were assessed for target effectors. The mRNA and protein levels of CXCR2 were significantly increased in the pulmonary tissue of CBDL rats. What's more, CXCR2 inhibition by SB225002 reduced the expression of CD68 and von Willebrand factor (vWf) in CBDL rats. Importantly, CXCR2 inhibition suppressed the activation of Akt and extracellular signal-regulated kinase (ERK) in CBDL rats. Antagonization of TNF-α with PTX down-regulated the expression of CXCR2. During HPS pathogenesis in rats, CXCR2 might be involved in the accumulation of pulmonary intravascular macrophages and angiogenesis, possibly by activating Akt and ERK, with additional regulation by TNF-α that enhanced pulmonary angiogenesis by directly acting on the pulmonary tissue. Finally, the present study may provide novel targets for the treatment of HPS.

Inhibition of autophagy ameliorates pulmonary microvascular dilation and PMVECs excessive proliferation in rat experimental hepatopulmonary syndrome.

Hepatopulmonary syndrome (HPS) is a defective liver-induced pulmonary vascular disorder with massive pulmonary microvascular dilation and excessive proliferation of pulmonary microvascular endothelial cells (PMVECs). Growing evidence suggests that autophagy is involved in pulmonary diseases, protectively or detrimentally. Thus, it is interesting and important to explore whether autophagy might be involved in and critical in HPS. In the present study, we report that autophagy was activated in common bile duct ligation (CBDL) rats and cultured pulmonary PMVECs induced by CBDL rat serum, two accepted in vivo and in vitro experimental models of HPS. Furthermore, pharmacological inhibition of autophagy with 3-methyladenine (3-MA) significantly alleviated pathological alterations and typical symptom of HPS in CBDL rats in vivo, and consistently 3-MA significantly attenuated the CBDL rat serum-induced excessive proliferation of PMVECs in vitro. All these changes mediated by 3-MA might explain the observed prominent improvement of pulmonary appearance, edema, microvascular dilatation and arterial oxygenation in vivo. Collectively, these results suggest that autophagy activation may play a critical role in the pathogenesis of HPS, and autophagy inhibition may have a therapeutic potential for this disease.

The angiogenic related functions of bone marrow mesenchymal stem cells are promoted by CBDL rat serum via the Akt/Nrf2 pathway

Hepatopulmonary syndrome (HPS) is a complication of severe liver disease. It is characterized by an arterial oxygenation defect. Recent studies have demonstrated that pulmonary angiogenesis contributes to the abnormal gas exchange found in HPS. Additionally, mesenchymal stem cells (MSCs) are considered the stable source of VEGF-producing cells and have the potential to differentiate into multiple cell types. However, it has not been determined whether bone marrow mesenchymal stem cells (BM-MSCs) are mobilized and involved in the pulmonary angiogenesis in HPS. In this study, a CFU-F assay showed that the number of peripheral blood MSCs was increased in common bile duct ligation (CBDL) rats; however, there was no significant difference found in the number of BM-MSCs. In vitro, CBDL rat serum induced the overexpression of CXCR4 and PCNA in BM-MSCs. Consistently, the directional migration as well as the proliferation ability of BM-MSCs were enhanced by CBDL rat serum, as determined by a transwell migration and MTT assays. Moreover, the secretion of VEGF by BM-MSCs increased after treatment with CBDL rat serum. We also found that the expression of phospho-Akt, phospho-ERK, and Nrf2 in BM-MSCs was significantly up-regulated by CBDL rat serum in a time dependent manner, and the blockage of the Akt/Nrf2 signalling pathway with an Akt Inhibitor or Nrf2 siRNA, instead of an ERK inhibitor, attenuated the migration, proliferation and paracrine capacity of BM-MSCs. In conclusion, these findings indicated that the number of MSCs increased in the peripheral blood of CBDL rats, and the Akt/Nrf2 pathway plays a vital role in promoting the angiogenic related functions of BM-MSCs, which could be a potent contributor to pulmonary angiogenesis in HPS.

Novel Gut Barrier Modulatory Effect of Vildagliptin in Amelioration of Bacterial Translocation in Cholestatic Rats

Intestinal barrier dysfunction is frequently implicated in the etiology of septic complications following obstructive jaundice. The present study was conducted to investigate the potential gut barrier modulating effect of vildagliptin (VLD), a dipeptidyl peptidase‐IV (DPP‐IV) inhibitor, on common bile duct ligation (CBDL) in rats. VLD (10 mg/kg/d; p.o) was administered for 10 successive days after CBDL in male Sprague‐Dawley rats. VLD reduced portal endotoxemia induced by CBDL and suppressed rectal temperature elevation, body weight loss and colon and spleen indices to different extends. Moreover, it reversed villous blunting, low villous density, mucosal thinning and inflammatory cell infiltration noticed microscopically in the ileal segments of the CBDL rats. These events were accompanied by the reduction of intestinal myeloperoxidase activity and lipid peroxidation, the elevation of the major anti‐oxidant molecule, glutathione, as well as the normalization of ileal nitric oxide level. Furthermore, ileal DPP‐IV was inhibited in association with the rise in ileal glucagon‐like peptide‐1 (GLP‐1) and insulin‐like growth factor‐1 (IGF‐1) levels in VLD treated animals. The current findings suggest that VLD anti‐oxidant, anti‐inflammatory, as well as enhancements of incretin and IGF‐1 account for the hardwearing of the intestinal barrier that functions competently in the absence of the supporting bile elements.