Reduction In Portal Pressure Research Articles

Modulation of hepatic perfusion did not improve recovery from hepatic outflow obstruction

BackgroundFocal hepatic venous outflow obstruction frequently occurs after extended liver resection and leads to a portal hypertension, arterial hypoperfusion and parenchymal necrosis.In this study, we investigated the pharmacological modulation of liver perfusion and hepatic damage in a surgical model of hepatic outflow obstruction after extended liver resection by administration of 5 different drugs in comparison to an operative intervention, splenectomy.MethodsMale inbred Lewis rats (Lew/Crl) were subjected to right median hepatic vein ligation + 70% partial hepatectomy. Treatment consisted of a splenectomy or the application of saline, carvedilol or isosorbide-5-mononitrate (ISMN) (5 mg · kg−1 respectively 7,2 mg · kg−1 per gavage 12 h−1). The splenectomy was performed during operation. The effect of the treatments on hepatic hemodynamics were measured in non-operated animals, immediately after operation (n = 4/group) and 24 h after operation (n = 5/group). Assessment of hepatic damage (liver enzymes, histology) and liver cell proliferation (BrdU-immunohistochemistry) was performed 24 h after operation. Furthermore sildenafil (10 μg · kg−1 i.p. 12h−1), terlipressin (0.05 mg · kg−1 i.v. 12 h−1) and octreotide (10 μg · kg−1 s.c. 12 h−1) were investigated regarding their effect on hepatic hemodynamics and hepatic damage 24 h after operation (n = 4/group).ResultsCarvedilol and ISMN significantly decreased the portal pressure in normal non-operated rats from 11,1 ± 1,1 mmHg (normal rats) to 8,4 ± 0,3 mmHg (carvedilol) respectively 7,4 ± 1,8 mmHg (ISMN). ISMN substantially reduced surgery-induced portal hypertension from 15,4 ± 4,4 mmHg to 9,6 ± 2,3 mmHg. Only splenectomy reduced the portal flow immediately after operation by approximately 25%. No treatment had an immediate effect on the hepatic arterial perfusion. In all treatment groups, portal flow increased by approximately 3-fold within 24 h after operation, whereas hepatic arterial flow decreased substantially. Neither treatment reduced hepatic damage as assessed 24 h after operation. The distribution of proliferating cells appeared very similar in all drug treated groups and the splenectomy group.ConclusionTransient relative reduction of portal pressure did not result in a reduction of hepatic damage. This might be explained by the development of portal hyperperfusion which was accompanied by arterial hypoperfusion.

Are the benefits of beta blockers in cirrhotics only related to decreased portal hypertension?

Liver cirrhosis remains a leading cause of death worldwide. Non-selective beta blockers (NSBB) have played a key role in the treatment of portal hypertension since Lebrec’s pioneering observations that propranolol significantly reduces portal pressure in patients with cirrhosis (1). At first, the reduction in portal pressure was ascribed to a reduced splanchnic blood flow as a consequence of a demonstrated lowered cardiac output. However, further studies demonstrated that the portal hypertensive state is maintained despite the formation of collaterals because of splanchnic vasodilatation and increased portal venous inflow, the so called hyperdynamic circulation (2). NSBB are known to be more effective in patients presenting with clinical significant portal hypertension (CSPH, i.e., an HVPG >10 mmHg) in which the hyperdynamic circulation is more pronounced (3).

Mitochondria‐targeted antioxidant mitoquinone deactivates human and rat hepatic stellate cells and reduces portal hypertension in cirrhotic rats

In cirrhosis, activated hepatic stellate cells (HSC) play a major role in increasing intrahepatic vascular resistance and developing portal hypertension. We have shown that cirrhotic livers have increased reactive oxygen species (ROS), and that antioxidant therapy decreases portal pressure. Considering that mitochondria produce many of these ROS, our aim was to assess the effects of the oral mitochondria-targeted antioxidant mitoquinone on hepatic oxidative stress, HSC phenotype, liver fibrosis and portal hypertension. Ex vivo: Hepatic stellate cells phenotype was analysed in human precision-cut liver slices in response to mitoquinone or vehicle. In vitro: Mitochondrial oxidative stress was analysed in different cell type of livers from control and cirrhotic rats. HSC phenotype, proliferation and viability were assessed in LX2, and in primary human and rat HSC treated with mitoquinone or vehicle. In vivo: CCl4 - and thioacetamide-cirrhotic rats were treated with mitoquinone (5mg/kg/day) or the vehicle compound, DecylTPP, for 2weeks, followed by measurement of oxidative stress, systemic and hepatic haemodynamic, liver fibrosis, HSC phenotype and liver inflammation. Mitoquinone deactivated human and rat HSC, decreased their proliferation but with no effects on viability. In CCl4 -cirrhotic rats, mitoquinone decreased hepatic oxidative stress, improved HSC phenotype, reduced intrahepatic vascular resistance and diminished liver fibrosis. These effects were associated with a significant reduction in portal pressure without changes in arterial pressure. These results were further confirmed in the thioacetamide-cirrhotic model. We propose mitochondria-targeted antioxidants as a novel treatment approach against portal hypertension and cirrhosis.

Hepatitis C is now curable, but what happens with cirrhosis and portal hypertension afterwards?

Results from the interferon era have demonstrated reversibility of cirrhosis following viral eradication, but only for patients in the initial stage of cirrhosis. Although direct-acting antivirals (DAA) represent revolutionary treatment of hepatitis C, there are currently no studies showing histological effects of therapy on a large number of cirrhotic patients. However, studies involving transient elastography demonstrated a rapid decrease in liver stiffness after successful DAA therapy, probably due to resolution of inflammation, rather than fibrosis regression, as the latter requires a longer period of time. Reversal of fibrosis and cirrhosis upon viral eradication is a prerequisite for the reduction of portal pressure, but this effect has only been observed for the subclinical stage of portal hypertension (PH). On the other hand, the majority of patients with clinically significant PH remain at risk of decompensation and death, despite hepatitis C virus cure, as PH remains high in this setting. This calls for novel therapeutic approaches.

Carvedilol suppresses circulating and hepatic IL-6 responsible for hepatocarcinogenesis of chronically damaged liver in rats

Carvedilol is an anti-oxidant non-selective β-blocker used for reduction of portal blood pressure, prophylaxis of esophageal varices development and bleeding in chronic liver diseases. Recently, it exhibited potent anti-inflammatory, anti-fibrotic, anti-proliferative and anti-carcinogenic effects. In the present study, we evaluated the possible suppressive effect of carvedilol on circulating and hepatic IL-6 levels responsible for hepatocarcinogenesis in a rat model of hepatic cirrhosis. Besides, its effect on hepatic STAT-3 levels, function tests, oxidative stress markers, and hydroxyproline content, hepatic tissue histopathological changes and immunohistochemical expression of E & N-cadherin. Nine-week-old male Wistar rats injected intraperitoneal by 1ml/kg 10% CCL4 in olive oil three times/week (every other day) for 12weeks to induce hepatic cirrhosis. Carvedilol (10mg/kg/day suspended in 0.5% CMC orally), silymarin (50mg/kg/day suspended in 0.5% CMC orally) or combination of both used to treat hepatic cirrhosis from 15th to 84th day. Our data showed that carvedilol and silymarin co-treatment each alone or in combination efficiently reduced the elevated serum IL-6, ALT, AST, ALP and BIL, hepatic IL-6, STAT-3, MDA levels and hydroxyproline content. In addition, it elevated the reduced serum ALB level, hepatic CAT activity and GSH level. Meanwhile, it apparently restored the normal hepatic architecture, collagen distribution and immunohistochemical E & N-cadherin expression. Furthermore, carvedilol was superior to silymarin in improving MDA level. Moreover, the combination of carvedilol and silymarin showed an upper hand in amelioration of the CCL4 induced hepatotoxicity than each alone. Therefore, carvedilol could be promising in prevention of hepatocarcinogenesis in chronic hepatic injuries.

Circulating lipocalin 2 is neither related to liver steatosis in patients with non-alcoholic fatty liver disease nor to residual liver function in cirrhosis

Lipocalin 2 (LCN2) is induced in the injured liver and associated with inflammation. Aim of the present study was to evaluate whether serum LCN2 is a non-invasive marker to assess hepatic steatosis in patients with non-alcoholic fatty liver disease (NAFLD) or residual liver function in patients with liver cirrhosis. Therefore, LCN2 was measured by ELISA in serum of 32 randomly selected patients without fatty liver (controls), 24 patients with ultrasound diagnosed NAFLD and 42 patients with liver cirrhosis mainly due to alcohol. Systemic LCN2 was comparable in patients with liver steatosis, those with liver cirrhosis and controls. LCN2 negatively correlated with bilirubin in both cohorts. In cirrhosis, LCN2 was not associated with more advanced liver injury defined by the CHILD-PUGH score and model for end-stage liver disease score. Resistin but not C-reactive protein or chemerin positively correlated with LCN2. LCN2 levels were not increased in patients with ascites or patients with esophageal varices. Consequently, reduction of portal pressure by transjugular intrahepatic portosystemic shunt did not affect LCN2 levels. Hepatic venous blood (HVS), portal venous blood and systemic venous blood levels of LCN2 were similar. HVS LCN2 was unchanged in patients with end-stage liver cirrhosis compared to those with well-compensated disease arguing against increased hepatic release. Current data exclude that serum LCN2 is of any value as steatosis marker in patients with NAFLD and indicator of liver function in patients with alcoholic liver cirrhosis.

Development of hyperdynamic circulation and response to β-blockers in compensated cirrhosis with portal hypertension.

Nonselective β-blockers are useful to prevent bleeding in patients with cirrhosis and large varices but not to prevent the development of varices in those with compensated cirrhosis and portal hypertension (PHT). This suggests that the evolutionary stage of PHT may influence the response to β-blockers. To characterize the hemodynamic profile of each stage of PHT in compensated cirrhosis and the response to β-blockers according to stage, we performed a prospective, multicenter (tertiary care setting), cross-sectional study. Hepatic venous pressure gradient (HVPG) and systemic hemodynamic were measured in 273 patients with compensated cirrhosis before and after intravenous propranolol (0.15 mg/kg): 194 patients had an HVPG ≥10 mm Hg (clinically significant PHT [CSPH]), with either no varices (n = 80) or small varices (n = 114), and 79 had an HVPG >5 and <10 mm Hg (subclinical PHT). Patients with CSPH had higher liver stiffness (P < 0.001), worse Model for End-Stage Liver Disease score (P < 0.001), more portosystemic collaterals (P = 0.01) and splenomegaly (P = 0.01) on ultrasound, and lower platelet count (P < 0.001) than those with subclinical PHT. Patients with CSPH had lower systemic vascular resistance (1336 ± 423 versus 1469 ± 335 dyne · s · cm(-5) , P < 0.05) and higher cardiac index (3.3 ± 0.9 versus 2.8 ± 0.4 L/min/m(2) , P < 0.01). After propranolol, the HVPG decreased significantly in both groups, although the reduction was greater in those with CSPH (-16 ± 12% versus -8 ± 9%, P < 0.01). The HVPG decreased ≥10% from baseline in 69% of patients with CSPH versus 35% with subclinical PHT (P < 0.001) and decreased ≥20% in 40% versus 13%, respectively (P = 0.001). Patients with subclinical PHT have less hyperdynamic circulation and significantly lower portal pressure reduction after acute β-blockade than those with CSPH, suggesting that β-blockers are more suitable to prevent decompensation of cirrhosis in patients with CSPH than in earlier stages.

Treatment of acute esophageal variceal bleeding in cirrhotic patients

Esophageal variceal bleeding is the most dangerous complication in cirrhotic patients and is accompanied by high mortality. Treatment strategy involves early diagnosis, maintaining vital body functions and specific therapy aimed at the provision of local hemostasis and reduction of portal pressure. To this end, it is currently recommended to combine vasoactive drug (mainly, terlipressin or somatostatin) therapy with endoscopic methods of hemostasis (sclerotherapy or ligation). The use of Sengstaken-Blakemore tube is appropriate only in cases of refractory bleeding if the above methods cannot be used. An alternative to balloon tamponade may be the installation of self-expandable metal stents. Although transjugular intrahepatic portosystemic shunting is an extremely useful technique for the treatment of acute bleeding from esophageal varices, currently it is viewed as second-line therapy. Urgent surgical intervention is rarely performed and can be considered only in case of failure of conservative and/or endoscopic therapy and being unable to use a transjugular intrahepatic portosystemic shunt for technical or organizational reasons or due to anatomic problems. Among surgical operations described in the literature are various kinds of portocaval anastomoses and azygoportal disconnection procedure. To improve the results of treatment of cirrhotic patients with acute esophageal variceal bleeding it seems important to stratify them by risk groups, which will allow one to tailor therapeutic approaches to the expected results. For example, to initiate early use of more aggressive methods in patients with predictors of poor outcomes, and to protect individuals with a good prognosis from unnecessary invasive procedures. It is hoped that further research will refine this hypothesis.

Addition of Somatostatin After Successful Endoscopic Variceal Ligation Does not Prevent Early Rebleeding in Comparison to Placebo: A Double Blind Randomized Controlled Trial

Efficacy of endoscopic sclerotherapy in controlling acute variceal bleeding is significantly improved when vasoactive drug is added. Endoscopic variceal ligation (EVL) is superior to sclerotherapy. Whether efficacy of EVL will also improve with addition of somatostatin is not known. We compared EVL plus somatostatin versus EVL plus placebo in control of acute variceal bleeding. Consecutive cirrhotic patients with acute esophageal variceal bleeding were enrolled. After emergency EVL, patients were randomized to receive either somatostatin (250mcg/hr) or placebo infusion. Primary endpoint was treatment failure within 5 days. Treatment failure was defined as fresh hematemesis ≥2h after start of therapy, or a 3gm drop in Hb, or death. 61 patients were enrolled (EVL plus somatostatin group, n=31 and EVL plus placebo group, n=30). The baseline characteristics were similar. Within the initial 5-day period, the frequency of treatment failure was similar in both the groups (EVL plus somatostatin group 8/31 [26%] versus EVL plus placebo group 7/30 [23%]; P=1.000). The mortality was also similar in the two groups (3/31 [10%] vs. 3/30 [10%]; P=1.000). Baseline HVPG ≥19mm Hg and active bleeding at index endoscopy were independent predictors of treatment failure. Addition of somatostatin infusion to EVL therapy does not offer any advantage in control of acute variceal bleeding or reducing mortality. The reason for this may be its failure to maintain sustained reduction in portal pressure for five days. Active bleeding at index endoscopy and high baseline HVPG should help choose early alternative treatment options. Trial registered with ClincalTrials.gov vide NCT01267669.

Prevention of Rebleeding From Esophageal Varices in Patients With Cirrhosis Receiving Small-Diameter Stents Versus Hemodynamically Controlled Medical Therapy

Patients with cirrhosis and variceal hemorrhage have a high risk of rebleeding. We performed a prospective randomized trial to compare the prevention of rebleeding in patients given a small-diameter covered stent vs those given hepatic venous pressure gradient (HVPG)-based medical therapy prophylaxis. We performed an open-label study of patients with cirrhosis (92% Child class A or B, 70% alcoholic) treated at 10 medical centers in Germany. Patients were assigned randomly more than 5 days after variceal hemorrhage to groups given a small covered transjugular intrahepatic portosystemic stent-shunt (TIPS) (8 mm; n = 90), or medical reduction of portal pressure (propranolol and isosorbide-5-mononitrate; n = 95). HVPG was determined at the time patients were assigned to groups (baseline) and 2 weeks later. In the medical group, patients with an adequate reduction in HVPG (responders) remained on the drugs whereas nonresponders underwent only variceal band ligation. The study was closed 10 months after the last patient was assigned to a group. The primary end point was variceal rebleeding. Survival, safety (adverse events), and quality of life (based on the Short Form-36 health survey) were secondary outcome measures. A significantly smaller proportion of patients in the TIPS group had rebleeding within 2 years (7%) than in the medical group (26%) (P = .002). A slightly higher proportion of patients in the TIPS group experienced adverse events, including encephalopathy (18% vs 8% for medical treatment; P = .05). Rebleeding occurred in 6 of 23 patients (26%) receiving medical treatment before hemodynamic control was possible. Per-protocol analysis showed that rebleeding occurred in a smaller proportion of the 32 responders (18%) than in nonresponders who received variceal band ligation (31%) (P = .06). Fifteen patients from the medical group (16%) underwent TIPS placement during follow-up evaluation, mainly for refractory ascites. Survival time and quality of life did not differ between both randomized groups. Placement of a small-diameter, covered TIPS was straightforward and prevented variceal rebleeding in patients with Child A or B cirrhosis more effectively than drugs, which often required step-by-step therapy. However, TIPS did not increase survival time or quality of life and produced slightly more adverse events. Clinical Trial no: ISRCTN 16334693.

Reduced serum chemerin in patients with more severe liver cirrhosis

Chemerin is a well-established modulator of immune cell function and its serum levels are induced in inflammatory diseases. Liver cirrhosis is associated with inflammation which is aggravated by portal hypertension. The objective of this study was to evaluate whether chemerin is induced in patients with more severe liver cirrhosis and portal hypertension. Chemerin has been measured by ELISA in the portal venous serum (PVS), systemic venous serum (SVS) and hepatic venous serum (HVS) of 45 patients with liver cirrhosis. Chemerin is higher in HVS compared to PVS in accordance with our recently published finding. SVS, HVS and PVS chemerin decline in patients with more advanced liver injury defined by the CHILD-PUGH score. Hepatic chemerin has been determined in a small cohort and is similarly expressed in normal and cirrhotic liver. MELD score and serum markers of liver and kidney function do not correlate with chemerin. There is a positive correlation of chemerin in all compartments with Quick prothrombin time and of SVS chemerin with systolic blood pressure. PVS chemerin is induced in patients with modest/massive ascites but this does not translate into higher HVS and SVS levels. Chemerin is not associated with variceal size. Reduction of portal pressure by transjugular intrahepatic portosystemic shunt does not affect chemerin levels. These data show that low chemerin in patients with more severe liver cirrhosis is associated with reduced Quick prothrombin time.

A Haemodynamic Analysis to Assess the Safe Dose of Carvedilol across Different Child Class of Liver Disease

Background: Literature regarding safe dose of carvedilol is limited and also safe dose across different child classes of chronic liver disease is not very clear. Aim: We aimed primarily to study, the effect of reasonably safe dose (12.5 mg) of carvedilol in acute reduction of portal pressure and compared it with chronic reduction of portal pressure, after Original Research Article Wani et al.; BJMMR, 7(5): 355-368, 2015; Article no.BJMMR.2015.342 356 proper optimization of dose of carvedilol. Second aim of our study was to define predictors of response for acute and chronic reduction of portal pressure and to assess difference in dose tolerated and response across different child class on chronic basis. Methods: One hundred two consecutive patients of cirrhosis of liver with significant portal hypertension were included and hepatic venous pressure gradient was measured at the base line and after 90 minutes of administration of 12.5 mg carvedilol. After proper dose optimization of carvedilol, hepatic venous pressure gradient was again measured after 3 months to assess the chronic response. Results: The mean age of study population was 58.3±6.6 years. A total of 42.2%, 31.9% and 26.6% patients had child class A, child class B and Child class C cirrhosis, respectively. Mean pre-drug hepatic venous pressure gradient was 16.75±2.12 mmHg which dropped to 13.07±2.32 mmHg after 90 minutes of administration of 12.5 mg of carvedilol. The mean drop of hepatic venous pressure gradient was 4.5±2.2 mmHg and 2.4±1.9 mmHg among responders and non-responders, respectively. Overall, 51% showed acute response while 49% were nonresponders. Low cardiac output and high mean arterial pressure were significantly predicting the acute response, while, low baseline cardiac output was found as an independent predictor. After dose optimization, number of responders increased from 52 to 62. Mean dose of carvedilol was higher in non–responders as compared to responders, though statistically insignificant (p>0.05). Mean reduction of hepatic venous pressure gradient from baseline and after 3 months was 5.5±1.7 mmHg and 2.8±1.6 mmHg among responders and non responders on chronic basis, respectively (p<0.001). Absence of any adverse events (OR 11.3, 95% CI; 1.9-67.8), and more than 2.5 mmHg fall in hepatic venous pressure gradient during acute response (OR 8.7, 95% CI; 3.1-25.3) were found as independent predictors of chronic response (p<0.05). Univariate analysis found that no adverse events, no ascites, low baseline cardiac output, more than 2.5 mmHg fall in hepatic venous pressure gradient during acute response, as predictors of chronic response. However, etiology, child class, variceal size (large vs small) and gender were not significantly associated with chronic response Conclusion: At safe dose and with proper optimization of dose, carvedilol may achieve greater response with minimum side effects among different child classes of liver disease.

Hepatic dimethylarginine-dimethylaminohydrolase1 is reduced in cirrhosis and is a target for therapy in portal hypertension

Portal hypertension is characterized by reduced hepatic eNOS activity. Asymmetric-dimethylarginine (ADMA), an eNOS inhibitor, is elevated in cirrhosis and correlates with the severity of portal hypertension. Dimethylarginine dimethylaminohydrolase-1 (DDAH-1) is the key enzyme metabolizing hepatic ADMA. This study characterized DDAH-1 in cirrhosis, and explored hepatic DDAH-1 reconstitution through farnesoid X receptor (FXR) agonism and DDAH-1 gene therapy. DDAH-1 immunohistochemistry was conducted on human cirrhosis and healthy liver tissue. Subsequently, sham-operated or bile-duct-ligated (BDL) cirrhosis rats were treated with the FXR agonist obeticholic acid (OA, 5 mg/kg) or vehicle for 5 days. Further, animals underwent hydrodynamic injection with DDAH-1-expressing plasmid or saline control, which resulted in the following groups: sham+saline, BDL+saline, BDL+DDAH-1-plasmid. Portal pressure (PP) measurements were performed. Plasma ALT was measured by COBAS INTEGRA, DDAH-1 expression by qPCR and Western blot, eNOS activity by radiometric assay. Immunohistochemistry and Western-blotting confirmed hepatic DDAH-1 was restricted to hepatocytes, and expression decreased significantly in cirrhosis. In BDL rats, reduced DDAH-1 expression was associated with elevated hepatic ADMA, reduced eNOS activity and high PP. OA treatment significantly increased DDAH-1 expression, reduced hepatic tissue ADMA, and increased liver NO generation. PP was significantly reduced in BDL+OA vs. BDL+vehicle (8±1 vs. 13.5±0.6 mmHg; p<0.01) with no change in the mean arterial pressure (MAP). Similarly, DDAH-1 hydrodynamic injection significantly increased hepatic DDAH-1 gene and protein expression, and significantly reduced PP in BDL+DDAH-1 vs. BDL+saline (p<0.01). This study demonstrates DDAH-1 is a specific molecular target for portal pressure reduction, through actions on ADMA-mediated regulation of eNOS activity. Our data support translational studies, targeting DDAH-1 in cirrhosis and portal hypertension.

Combination of splanchnic vasoconstrictors and endoscopic band ligation is an effective treatment strategy for acute variceal hemorrhage; but how do we get those drugs approved by the FDA?

Combination of splanchnic vasoconstrictors and endoscopic band ligation is an effective treatment strategy for acute variceal hemorrhage; but how do we get those drugs approved by the FDA?

Elevated Liver Regeneration in Response to Pharmacological Reduction of Elevated Portal Venous Pressure by Terlipressin After Partial Hepatectomy

Liver regeneration is of crucial importance for patients undergoing living liver transplantations or extended liver resections and can be associated with elevated portal venous pressure, impaired hepatic regeneration, and postoperative morbidity. The aim of this study was to assess whether reduction of portal venous pressure by terlipressin improves postoperative liver regeneration in normal and steatotic livers after partial hepatectomy in a rodent model. Portal venous pressure was assessed after minor (30%), standard (60%), or extended (80%) partial hepatectomy (PH) in mice with and without liver steatosis. Liver regeneration was assessed by BrdU incorporation and Ki-67 immunostaining. Portal venous pressure was significantly elevated post-PH in mice with normal and steatotic livers compared to sham-operated mice. Reduction of elevated portal pressure after 80% PH by terlipressin was associated with an increase of hepatocellular proliferation. In steatotic livers, animals treated with terlipressin had an increase in liver regeneration after 30% PH and increased survival after 60% PH. Mechanistically, terlipressin alleviated IL-6 mRNA expression following PH and down-regulated p21 and GADD45 mRNA suggesting a reduction of cell cycle inhibition and cellular stress. Reduction of elevated portal pressure post-PH by the use of terlipressin improves liver regeneration after PH in lean and steatotic mouse livers.

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Relaxin modulates human and rat hepatic myofibroblast function and ameliorates portal hypertension in vivo.

Active myofibroblast (MF) contraction contributes significantly to the increased intrahepatic vascular resistance that is the primary cause of portal hypertension (PHT) in cirrhosis. We sought proof of concept for direct therapeutic targeting of the dynamic component of PHT and markers of MF activation using short-term administration of the peptide hormone relaxin (RLN). We defined the portal hypotensive effect in rat models of sinusoidal PHT and the expression, activity, and function of the RLN-receptor signaling axis in human liver MFs. The effects of RLN were studied after 8 and 16 weeks carbon tetrachloride intoxication, following bile duct ligation, and in tissue culture models. Hemodynamic changes were analyzed by direct cannulation, perivascular flowprobe, indocyanine green imaging, and functional magnetic resonance imaging. Serum and hepatic nitric oxide (NO) levels were determined by immunoassay. Hepatic inflammation was assessed by histology and serum markers and fibrosis by collagen proportionate area. Gene expression was analyzed by quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and western blotting and hepatic stellate cell (HSC)-MF contractility by gel contraction assay. Increased expression of RLN receptor (RXFP1) was shown in HSC-MFs and fibrotic liver diseases in both rats and humans. RLN induced a selective and significant reduction in portal pressure in pathologically distinct PHT models, through augmentation of intrahepatic NO signaling and a dramatic reduction in contractile filament expression in HSC-MFs. Critical for translation, RLN did not induce systemic hypotension even in advanced cirrhosis models. Portal blood flow and hepatic oxygenation were increased by RLN in early cirrhosis. Treatment of human HSC-MFs with RLN inhibited contractility and induced an antifibrogenic phenotype in an RXFP1-dependent manner. We identified RXFP1 as a potential new therapeutic target for PHT and MF activation status.

L-Ornithine Phenylacetate (OCR-002) Ameliorates Portal Hypertension by Modulating NFKB Driven Inflammatory Pathway in Cirrhosis

Background and Aims: Hyperammonemia induces oxidative stress and NF-kB in astrocytes and has been shown to reduce the bioavailability of nitric oxide. In cirrhosis, portal hypertension is associated with hepatic inflammation which contributes to reduced intrahepatic endothelial nitric oxide synthase (eNOS) activity, which we previously show to be associated with the increased endogenous NOS inhibitors, Caveolin-1 and asymmetric-dimethylarginine (ADMA). This study was designed to test the hypothesis that correcting hyperammonaemia with L-ornithine phenylacetate (OCR-002) will reduce NF-κβ and increase intrahepatic NO availability through modulation of these inflammatory dependent inhibitors of endothelial NOS and reduce portal pressure. Methods: Sprague-Dawley rats were studied 4-weeks after BDL surgery (n = 16) or sham operation (n = 8) and randomised to treatment with placebo or OCR-002 (0.6 gm/Kg) i.p. for 5 days prior to study. Rats underwent direct portal pressure measurement under anaesthesia at the time of sacrifice and plasma and liver tissue was harvested for subsequent analysis. Plasma ammonia and biochemistry were measured using a Cobas-MiraS analyser, plasma TNFa by FACS bead assay and eNOS activity was determined radiometrically. Protein expression for NF-κβ, iNOS, 3-nitrotyrosine, 4-HNE, eNOS, peNOS, DDAH-1 and Caveolin-1 were measured using Western Blotting. Results: Treatment with OCR-002 resulted in a reduction in hyperammonaemia (P < 0.001) and plasma TNFa concentrations (P < 0.05) towards sham values and an increase in hepatic eNOS activity towards sham levels. This was associated with a significant reduction in portal pressure compared with the placebo treated group (11.1 ± 0.4 vs. 14.4 ± 0.7 mmHg, P < 0.01). Moreover, OCR-002 treatment significantly reduced the expression of Caveolin-1 (P < 0.05) and increased expression of dimethylarginine-dimethylamainohydrolase-1 (P < 0.05) [DDAH 1- responsible for metabolism of ADMA], whilst also significantly lowering hepatic phosphorylated NF-kB, iNOS and 3-nitrotyrosine expressions, compared with placebo treatment. Conclusion: Our study is the first demonstration of evidence that the significant association between hyperammonaemia and portal hypertension. Treatment of hyperammonemia with OCR-002 reduces the severity of portal hypertension in a clinically relevant model of cirrhosis through restoration of the hepatic eNOS activity, by modulating for NF-κβ driven inflammatory signaling and expression of the eNOS regulators, DDAH1-ADMA and caveolin-1. Thus, our data provide the rationale for evaluating OCR-002 in the treatment of portal hypertension. Keywords: eNOS dysfunction, Hyperammonemia, Inflammation, L-Ornithine Phenylacetate, Portal hypertension.

Glytan decreases portal pressure via mesentery vasoconstriction in portal hypertensive rats.

To investigate the effects of Glytan on splanchnic hemodynamics and its reduction of portal pressure in portal hypertensive rats. Glytan (Ganluotong in Chinese), is composed of salvianolic acid B and diammonium glycyrrhizinate. Portal hypertension (PHT) was induced in the rats by common bile duct ligation (BDL). Hemodynamic studies were performed using the colored microsphere method. Radioimmunoassay (RIA) was used to determine endothelin (ET)-1 levels in the mesenteric circulation. Western blotting methods were used to investigate the effect of Glytan on ET A receptor (ETAR), ET B receptor (ETBR), endothelial NO synthase (eNOS), G-protein-coupled receptor kinase (GRK)2, and β-arrestin 2 expression in the mesentery. The mRNA of ETAR and ETBR was determined using real-time polymerase chain reaction. Treatment with Glytan reduced portal pressure (PP) and portal territory blood flow (PTBF) and increased both mean arterial pressure (MAP) and splanchnic vascular resistance (SVR). Especially at 4 wk, PP decreased by about 40%, while MAP increased by 13%, SVR increased by 12%, and PTBF decreased by about 21%. The effect of blood flow reduction was greatest in the mesentery (about 33%) at 4 wk. The mesenteric circulation ET-1 levels of BDL rats were lower and negatively correlated with PP at 4 wk. Glytan can increase mesenteric ET-1 content and inhibit ETBR, eNOS, GRK2, and β-arrestin 2 expression in the mesentery. Moreover, Glytan showed no effect on the expression of ETAR protein and mRNA. The decreased PP and PTBF observed after Glytan treatment were related to increased mesenteric vasoconstriction and increased receptor sensitivity to vasoconstrictor.

Portal hypertensive enteropathy.

Portal hypertensive enteropathy (PHE) is a condition that describes the pathologic changes and mucosal abnormalities observed in the small intestine of patients with portal hypertension. This entity is being increasingly recognized and better understood over the past decade due to increased accessibility of the small intestine made possible by the introduction of video capsule endoscopy and deep enteroscopy. Though challenged by its diverse endoscopic appearance, multiple scoring systems have been proposed to classify the endoscopic presentation and grade its severity. Endoscopic findings can be broadly categorized into vascular and non-vascular lesions with many subtypes of both categories. Clinical manifestations of PHE can range from asymptomatic incidental findings to fatal gastrointestinal hemorrhage. Classic endoscopic findings in the setting of portal hypertension may lead to a prompt diagnosis. Occasionally histopathology and cross sectional imaging like computed tomography or magnetic resonance imaging may be helpful in establishing a diagnosis. Management of overt bleeding requires multidisciplinary approach involving hepatologists, endoscopists, surgeons, and interventional radiologists. Adequate resuscitation, reduction of portal pressure, and endoscopic therapeutic intervention remain the main principles of the initial treatment. This article reviews the existing evidence on PHE with emphasis on its classification, diagnosis, clinical manifestations, endoscopic appearance, pathological findings, and clinical management. A new schematic management of ectopic variceal bleed is also proposed.