Complications of cirrhosis. I. Portal hypertension

Experimental liver fibrosis research: update on animal models, legal issues and translational aspects

Liver fibrosis is defined as excessive extracellular matrix deposition and is based on complex interactions between matrix-producing hepatic stellate cells and an abundance of liver-resident and infiltrating cells. Investigation of these processes requires in vitro and in vivo experimental work in animals. However, the use of animals in translational research will be increasingly challenged, at least in countries of the European Union, because of the adoption of new animal welfare rules in 2013. These rules will create an urgent need for optimized standard operating procedures regarding animal experimentation and improved international communication in the liver fibrosis community. This review gives an update on current animal models, techniques and underlying pathomechanisms with the aim of fostering a critical discussion of the limitations and potential of up-to-date animal experimentation. We discuss potential complications in experimental liver fibrosis and provide examples of how the findings of studies in which these models are used can be translated to human disease and therapy. In this review, we want to motivate the international community to design more standardized animal models which might help to address the legally requested replacement, refinement and reduction of animals in fibrosis research.

Terutroban, a TP-receptor antagonist, reduces portal pressure in cirrhotic rats

Increased production of vasoconstrictive prostanoids, such as thromboxane A2 (TXA2 ), contributes to endothelial dysfunction and increased hepatic vascular tone in cirrhosis. TXA2 induces vasoconstriction by way of activation of the thromboxane-A2 /prostaglandin-endoperoxide (TP) receptor. This study investigated whether terutroban, a specific TP receptor blocker, decreases hepatic vascular tone and portal pressure in rats with cirrhosis due to carbon tetrachloride (CCl4 ) or bile duct ligation (BDL). Hepatic and systemic hemodynamics, endothelial dysfunction, liver fibrosis, hepatic Rho-kinase activity (a marker of hepatic stellate cell contraction), and the endothelial nitric oxide synthase (eNOS) signaling pathway were measured in CCl4 and BDL cirrhotic rats treated with terutroban (30 mg/kg/day) or its vehicle for 2 weeks. Terutroban reduced portal pressure in both models without producing significant changes in portal blood flow, suggesting a reduction in hepatic vascular resistance. Terutroban did not significantly change arterial pressure in CCl4 -cirrhotic rats but decreased it significantly in BDL-cirrhotic rats. In livers from CCl4 and BDL-cirrhotic terutroban-treated rats, endothelial dysfunction was improved and Rho-kinase activity was significantly reduced. In CCl4 -cirrhotic rats, terutroban reduced liver fibrosis and decreased alpha smooth muscle actin (α-SMA), collagen-I, and transforming growth factor beta messenger RNA (mRNA) expression without significant changes in the eNOS pathway. In contrast, no change in liver fibrosis was observed in BDL-cirrhotic rats but an increase in the eNOS pathway.

CONCLUSION

Our data indicate that TP-receptor blockade with terutroban decreases portal pressure in cirrhosis. This effect is due to decreased hepatic resistance, which in CCl4 -cirrhotic rats was linked to decreased hepatic fibrosis, but not in BDL rats, in which the main mediator appeared to be an enhanced eNOS-dependent vasodilatation, which was not liver-selective, as it was associated with decreased arterial pressure. The potential use of terutroban for portal hypertension requires further investigation.

Celecoxib ameliorates portal hypertension of the cirrhotic rats through the dual inhibitory effects on the intrahepatic fibrosis and angiogenesis

BACKGROUND

Increased intra-hepatic resistance to portal blood flow is the primary factor leading to portal hypertension in cirrhosis. Up-regulated expression of cyclooxygenase-2 (COX-2) in the cirrhotic liver might be a potential target to ameliorate portal hypertension.

OBJECTIVE

To verify the effect of celecoxib, a selective inhibitor of COX-2, on portal hypertension and the mechanisms behind it.

METHODS

Cirrhotic liver model of rat was established by peritoneal injection of thiacetamide (TAA). 36 rats were randomly assigned to control, TAA and TAA+celecoxib groups. Portal pressures were measured by introduction of catheters into portal vein. Hepatic fibrosis was assessed by the visible hepatic fibrotic areas and mRNAs for collagen III and α-SMA. The neovasculature was determined by hepatic vascular areas, vascular casts and CD31 expression. Expressions of COX-2, vascular endothelial growth factor (VEGF), VEGF receptor-2 (VEGFR-2) and related signal molecules were quantitated.

RESULTS

Compared with TAA group, the portal pressure in TAA+celecoxib group was significantly decreased by 17.8%, p<0.01. Celecoxib treatment greatly reduced the tortuous hepatic portal venules. The data of fibrotic areas, CD31expression, mRNA levels of α-SMA and collagen III in TAA+celecoxib group were much lower than those in TAA group, p<0.01. Furthermore, the up-regulation of hepatic mRNA and protein levels of VEGF, VEGFR-2 and COX-2 induced by TAA was significantly inhibited after celecoxib treatment. The expressions of prostaglandin E2 (PGE2), phosphorylated extracellular signal-regulated kinase (p-ERK), hypoxia-inducible factor-1α (HIF-1α), and c-fos were also down-regulated after celecoxib treatment.

CONCLUSIONS

Long term administration of celecoxib can efficiently ameliorate portal hypertension in TAA rat model by its dual inhibitory effects on the intrahepatic fibrosis and angiogenesis. The anti-angiogenesis effect afforded by celecoxib may attribute to its modulation on VEGF/VEGFR-2 through the down-regulation of integrated signal pathways involving PGE2- HIF-1α- VEGF and p-ERK- c-fos- VEGFR-2.

Festival food coma in cystic fibrosis

Children with cystic fibrosis liver disease and portal hypertension are at risk of developing acute hepatic encephalopathy. Even in the presence of normal synthetic liver function these children may have porto-systemic shunting. We report a case of an adolosecent who had cystic fibrosis liver disease and presented with life threatening hepatinc encephalopathy. This case illustrates that it is necessary to consider an appropriate dietary regimen in adolosecents with liver disease to prevent hepatic decompensation.

Comparative randomized study on efficacy of losartan versus propranolol in lowering portal pressure in decompensated chronic liver disease

OBJECTIVE

This study aimed to compare the efficacy of losartan, an angiotensin II receptor antagonist, with propranolol on portal hypertension in patients with decompensated chronic liver disease.

METHODS

In all, 30 patients with Child-Pugh B cirrhosis and large varices without any prior therapy for portal hypertension were randomized to either losartan (n = 15) or propranolol (n = 15). Clinical, biochemical and hemodynamic parameters including hepatic venous pressure gradient (HVPG), wedged hepatic venous pressure (WHVP), mean arterial blood pressure (MABP) and free hepatic venous pressure (FHVP) were measured at baseline and after 4-week therapy. Patients with HVPG < 12 mmHg were regarded as responders.

RESULTS

An equal number of responders were seen in both groups (6/15, 40.0%). The reduction of WHVP and HVPG was greater in the losartan group than in the propranolol group, although no significant differences between them were found. Heart rate decreased more in the propranolol arm than in the losartan arm (P < 0.01); however, no correlation between the decrease of heart rate and the reduction of HVPG was observed. One patient in the losartan group, although a responder, had gastrointestinal bleeding 2 months after the drug administration, but the varices were small under endoscopy and did not require definitive therapy. The fall of MABP was greater with losartan, with no statistical difference between the two groups.

CONCLUSION

The effect of losartan was comparable to propranolol in reducing portal pressure in decompensated Child-Pugh B chronic liver disease.

Austrian consensus on the definition and treatment of portal hypertension and its complications (Billroth II)

In November 2004, the Austrian Society of Gastroenterology and Hepatology (ÖGGH) held for the first time a consensus meeting on the definitions and treatment of portal hypertension and its complications in the Billroth-Haus in Vienna, Austria (Billroth I-Meeting). This meeting was preceded by a meeting of international experts on portal hypertension with some of the proponents of the Baveno consensus conferences (http://www.oeggh.at/videos.asp). The consensus itself is based on the Baveno III consensus with regard to portal hypertensive bleeding and the suggestions of the International Ascites Club regarding the treatment of ascites. Those statements were modified by new knowledge derived from the recent literature and also by the current practice of medicine as agreed upon by the participants of the consensus meeting. In October 2011, the ÖGGH organized the second consensus meeting on portal hypertension and its complications in Vienna (Billroth II-Meeting). The Billroth II-Guidelines on the definitions and treatment of portal hypertension and its complications take into account the developments of the last 7 years, including the Baveno-V update and several key publications.

Nebivolol treatment increases splanchnic blood flow and portal pressure in cirrhotic rats via modulation of nitric oxide signalling

BACKGROUND

We evaluated the effects of nebivolol, a third generation beta-blocker capable of increasing NO-bioavailability on portal pressure, and on splachnic and systemic haemodynamics in a cirrhotic portal hypertensive rat model.

METHODS

Male Sprague-Dawley rats underwent sham operation (SO) or bile duct ligation (BDL). When cirrhosis was fully developed, the animals were orally treated with low-dose (5 mg/kg) or high-dose (10 mg/kg) nebivolol (NEBI) or vehicle (VEH) for 7 days. Heart rate (HR), mean arterial pressure (MAP), portal pressure (PP) and superior mesenteric artery blood flow (SMABF) were measured. Portosystemic collateral blood flow (PSCBF) was quantified using radioactive microspheres. Hepatic and splanchnic NOx levels and GSH/GSSG ratios (RedOx state) were determined using commercially available kits.

RESULTS

BDL-VEH rats showed increased HR, PP and PSCBF, whereas MAP was decreased compared to SO-VEH rats. Nebivolol significantly reduced HR both in SO (P < 0.001) and BDL (P < 0.001) rats. BDL-NEBI animals had significantly higher PP (15.5 vs. 12.6 mmHg; P = 0.006) and SMABF (5.3 vs. 3.7 ml/min/100g; P = 0.016) than BDL-VEH animals. The increase in PP and SMABF was noted both in low-dose and high-dose BDL-NEBI rats. While no beneficial effects on hepatic RedOx state were observed, splanchnic NOx levels were significantly increased by NEBI treatment in a dose-dependent manner. Nebivolol treatment did not affect PSCBF in SO and BDL animals.

CONCLUSION

Nebivolol increases portal pressure in cirrhotic animals by increasing splanchnic blood flow via modulation of NO signalling. Portosystemic collateral blood flow remained unchanged. These data do not support the use of nebivolol for treatment of cirrhotic patients with portal hypertension.

Interaction between NO and COX pathways modulating hepatic endothelial cells from control and cirrhotic rats

Reduced intrahepatic nitric oxide (NO) bioavailability and increased cyclooxygenase-1 (COX-1)-derived vasoconstrictor prostanoids modulate the hepatic vascular tone in cirrhosis. We aimed at investigating the reciprocal interactions between NO and COX in the hepatic endothelium of control and cirrhotic rats. NO bioavailability (DAF-FM-DA staining), superoxide (O₂⁻) content (DHE staining), prostanoid production (PGI₂ and TXA₂ by enzyme immunoassays) as well as COX expression (Western Blot), were determined in hepatic endothelial cells (HEC) from control and cirrhotic rats submitted to different experimental conditions: COX activation, COX inhibition, NO activation and NO inhibition. In control and cirrhotic HEC, COX activation with arachidonic acid reduced NO bioavailability and increased O₂⁻ levels. These effects were abolished by pre-treating HEC with the COX inhibitor indomethacin. In control, but not in cirrhotic HEC, scavenging of O₂⁻ by superoxide dismutase (SOD) incubation partially restored the decrease in NO bioavailability promoted by COX activation. NO supplementation produced a significant and parallel reduction in PGI₂ and TXA₂ production in control HEC, whereas it only reduced TXA₂ production in cirrhotic HEC. By contrast, in control and cirrhotic HEC, NO inhibition did not modify COX expression or activity. Our results demonstrate that NO and COX systems are closely interrelated in HEC. This is especially relevant in cirrhotic HEC where COX inhibition increases NO bioavailability and NO supplementation induces a reduction in TXA₂. These strategies may have beneficial effects ameliorating the vasoconstrictor/vasodilator imbalance of the intrahepatic circulation of cirrhotic livers.

Recombinant human manganese superoxide dismutase reduces liver fibrosis and portal pressure in CCl4-cirrhotic rats

BACKGROUND & AIMS

High oxidative stress plays a major role in increasing hepatic vascular resistance in cirrhosis, by facilitating liver fibrosis and by increasing hepatic vascular tone. This study is aimed at investigating whether the use of the novel isoform of recombinant human manganese superoxide dismutase (rMnSOD) could be a new therapeutic strategy to reduce oxidative stress and portal hypertension in cirrhotic rats.

METHODS

In CCl(4)- and BDL-cirrhotic rats treated with rMnSOD (i.p. 15 μg/kg/day) or its vehicle for 7 days, mean arterial pressure (MAP), portal pressure (PP) and portal blood flow (PBF) or small mesenteric arterial flow (SMABF) were measured. In addition, in CCl(4)-cirrhotic rats, we evaluated the hepatic vasodilatory response to acetylcholine, liver fibrosis with Sirius red staining and hepatic stellate cell activation by α-smooth muscle actin (α-SMA) protein expression.

RESULTS

rMnSOD treatment significantly reduced PP either in CCl(4)- or BDL-cirrhotic rats without significant changes in splanchnic blood flow, suggesting a reduction in hepatic vascular resistance. MAP was not modified. Reduction in PP was associated with a significant reduction in liver fibrosis, and α-SMA protein expression as well as with improved vasodilatory response to acetylcholine.

CONCLUSIONS

Chronic rMnSOD administration to cirrhotic rats reduces portal pressure by reducing hepatic vascular resistance without deleterious effects on systemic hemodynamics, suggesting that it might constitute a new antioxidant to be considered as additional therapy for treating portal hypertension in cirrhosis.

Zolmitriptan: a novel portal hypotensive agent which synergizes with propranolol in lowering portal pressure

OBJECTIVE

Only a limited proportion of patients needing pharmacological control of portal hypertension are hemodynamic responders to propranolol. Here we analyzed the effects of zolmitriptan on portal pressure and its potential interaction with propranolol.

METHODS

ZOLMITRIPTAN, PROPRANOLOL OR BOTH WERE TESTED IN TWO RAT MODELS OF PORTAL HYPERTENSION: common bile duct ligation (CBDL) and CCl4-induced cirrhosis. In these animals we measured different hemodynamic parameters including portal venous pressure, arterial renal flow, portal blood flow and cardiac output. We also studied the changes in superior mesenteric artery perfusion pressure and in arterial wall cAMP levels induced by zolmitriptan, propranolol or both. Moreover, we determined the effect of splanchnic sympathectomy on the response of PVP to zolmitriptan.

RESULTS

In both models of portal hypertension zolmitriptan induced a dose-dependent transient descent of portal pressure accompanied by reduction of portal flow with only slight decrease in renal flow. In cirrhotic rats, splanchnic sympathectomy intensified and prolonged zolmitriptan-induced portal pressure descent. Also, propranolol caused more intense and durable portal pressure fall when combined with zolmitriptan. Mesenteric artery perfusion pressure peaked for about 1 min upon zolmitriptan administration but showed no change with propranolol. However propranolol enhanced and prolonged the elevation in mesenteric artery perfusion pressure induced by zolmitriptan. In vitro studies showed that propranolol prevented the inhibitory effects of β2-agonists on zolmitriptan-induced vasoconstriction and the combination of propranolol and zolmitriptan significantly reduced the elevation of cAMP caused by β2-agonists.

CONCLUSION

Zolmitriptan reduces portal hypertension and non-selective beta-blockers can improve this effect. Combination therapy deserves consideration for patients with portal hypertension failing to respond to non-selective beta-blockers.

The wound-healing response and upregulated embryonic mechanisms: brothers-in-arms forever

The cutaneous wound-healing reaction occurs in overlapping but inter-related phases, which ultimately result in fibrosis. The pathophysiological mechanisms involved in fibrotic diseases, including organ-related and even systemic diseases, such as systemic sclerosis, could represent the successive systemic upregulation of extraembryonic-like phenotypes, that is, amniotic and vitelline phenotypes. These two extraembryonic-like phenotypes act on the injured tissue to induce a process similar to gastrulation, which occurs during the early phases of embryo development. The amniotic-like phenotype plays a leading role in the development of neurogenic responses with significant hydroelectrolytic alterations that essentially represent the development of open microcirculation within the injured tissue. In turn, through the overlapping expression of a vitelline-like phenotype, a bone marrow-related response is produced. Interstitial infiltration by molecular and cellular mediators contributed by amniotic- and vitelline-like functions provides the functional and metabolic autonomy needed for inducing new tissue formation through mechanisms similar to those that act in gastrulation during the early phases of embryonic development. Thus, while a new tissue is formed, it quickly evolves into fibrotic tissue because of premature senescence. Mechanisms related to extraembryonic-like functions have been suggested in the following physiological and pathological processes: embryonic development; wound-healing reactions occurring during adult life; and senescence. The existence of this sort of basic self-organizing fractal-like functional pattern is an essential characteristic of our way of life.

HSC-specific inhibition of Rho-kinase reduces portal pressure in cirrhotic rats without major systemic effects

BACKGROUND & AIMS

Rho-kinase activation mediates cell contraction and increases intrahepatic resistance and consequently portal pressure in liver cirrhosis. Systemic Rho-kinase inhibition decreases portal pressure in cirrhosis, but also arterial pressure. Thus, liver-specific Rho-kinase inhibition is needed. The delivery of Rho-kinase inhibitor to activated hepatic stellate cells reduces fibrosis. It might also relax these contractile cells and therewith decrease intrahepatic resistance. We tested this hypothesis by performing acute experiments in cirrhotic rats.

METHODS

Cirrhosis models were CCl(4)-intoxication and bile duct ligation. Three hours after injection of the Rho-kinase inhibitor (Y26732) coupled with a carrier (mannose-6-phosphate modified human serum albumin), which targets activated hepatic stellate cells, hemodynamics were analyzed by the colored microsphere technique and direct pressure measurements. The delivery site and effect of Rho-kinase inhibitor were investigated by immunohistochemical stainings, as well as Western blot. Experiments with Rho-kinase inhibitor coupled with unmodified human serum albumin served as untargeted control.

RESULTS

In both models of cirrhosis, the carrier coupled Rho-kinase inhibitor lowered the portal pressure and decreased the hepatic-portal resistance. Immunohistochemical desmin-staining showed the carrier in hepatic stellate cells. The targeted therapy decreased the expression of the phosphorylated substrate of Rho-kinase (moesin) and abolished myosin light chains phosphorylation in fibrotic septae (collagen-staining). The targeted Rho-kinase inhibitor showed no major extrahepatic effects. By contrast, the untargeted Rho-kinase inhibitor elicited severe systemic hypotension.

CONCLUSIONS

Activated hepatic stellate cells are crucially involved in portal hypertension in cirrhosis. Targeting of Rho-kinase in hepatic stellate cells not only decreased fibrosis, as previously shown, but also lowers portal pressure acutely without major systemic effects as demonstrated in this study.

A prospective evaluation of pulmonary, systemic and hepatic haemodynamics in HIV-HCV-coinfected patients before and after antiviral therapy with pegylated interferon and ribavirin

BACKGROUND

Patients coinfected with HIV and HCV are at risk for developing portal hypertension (PHT), hyperdynamic circulation and pulmonary arterial hypertension (PAH). Data on the influence of antiviral therapy with pegylated interferon-α (PEG-IFN-α) and ribavirin (RBV) are limited.

METHODS

Haemodynamic parameters, including hepatic venous pressure gradient (HVPG), pulmonary arterial pressure (PAP(mean)), cardiac output (CO) and systemic vascular resistance (SysVR), were prospectively evaluated before and after PEG-IFN-α+RBV therapy in 80 HIV-HCV-coinfected patients.

RESULTS

Baseline evaluation showed a mean HVPG of 4.7 mmHg, CO of 6.15 l/min and PAP(mean) of 14.8 mmHg. PHT was present in 26% of patients, hyperdynamic circulation in 5% and PAH in 4%. Patients with advanced fibrosis (METAVIR stage F3/F4; n=32) had significantly higher CO (P=0.008), lower SysVR (P=0.035), higher PAP(mean) (P=0.018) and higher pulmonary vascular resistance (P=0.022) than patients with stage F0-F2 fibrosis (n=48). Both hyperdynamic circulation and PAH were significantly associated with liver stiffness, fibrosis stage and portal pressure; a non-significant trend was found for CD4(+) T-cell counts and HIV RNA levels. No significant changes in PAP(mean), CO and SysVR were observed after PEG-IFN-α+RBV treatment, although a significant decrease in HVPG was noted in patients with HCV eradication (P=0.013).

CONCLUSIONS

The overall prevalence of hyperdynamic circulation and PAH in HIV-HCV coinfection is low. Advanced fibrosis, increased liver stiffness, elevated portal pressure and probably CD4(+) T-cell count and HIV viraemia represent risk factors for hyperdynamic circulation and PAH. PHT is present in 26% of HIV-HCV-coinfected patients evaluated for antiviral therapy. Successful HCV eradication significantly decreases HVPG.

Endoscopic management of esophageal varices

The rupture of gastric varices results in variceal hemorrhage, which is one the most lethal complications of cirrhosis. Endoscopic therapies for varices aim to reduce variceal wall tension by obliteration of the varix. The two principal methods available for esophageal varices are endoscopic sclerotherapy (EST) and band ligation (EBL). The advantages of EST are that it is cheap and easy to use, and the injection catheter fits through the working channel of a diagnostic gastroscope. Endoscopic variceal ligation obliterates varices by causing mechanical strangulation with rubber bands. The following review aims to describe the utility of EBL and EST in different situations, such as acute bleeding, primary and secondary prophylaxis

Noninvasive screening for liver fibrosis and portal hypertension by transient elastography--a large single center experience

BACKGROUND

Transient elastography (TE) is a noninvasive tool to assess hepatic fibrosis by measuring liver stiffness (LS). Recent studies suggest that TE may be used to screen for liver cirrhosis and clinically significant portal hypertension (≥ 10 mmHg; CSPH), whereas data on the clinical applicability of TE are limited.

METHODS

Among 695 patients undergoing measurement of LS, data on liver biopsies and on hepatic venous pressure gradient (HVPG) were available in 290 and 502 patients, respectively. Analysis of the area under the receiver operating curve (AUC) was used to assess the positive (PPV) and negative predictive (NPV) values of LS cut-offs for staging of hepatic fibrosis and for diagnosis of CSPH.

RESULTS

LS was significantly associated with fibrosis stage (R = 0.872;p < 0.0001). AUC for diagnosis of fibrosis F2 (> 7.2 kPa) was 0.690, 0.737 for F3 (> 9.6 kPa), and 0.904 for F4 (> 12.1 kPa), respectively. At a LS cut-off of 12.1 kPa the PPV and NPV for diagnosis of cirrhosis were 87 and 91 %, respectively. A significant correlation of LS and HVPG was noted (R = 0.794;p < 0.0001), being stronger in patients with viral disease (R = 0.838;p < 0.0001) than in patients with alcoholic disease (R = 0.756;p < 0.0001). The LS cut-off at 18 kPa can identify CSPH with a PPV and NPV of 86 and 80 %, respectively.

CONCLUSIONS

This large single center study confirms the clinical utility of TE as valuable noninvasive screening tool for liver fibrosis with excellent accuracy to rule out F4 cirrhosis. However, the moderate PPV and NPV limit the diagnostic use of TE for discriminating patients with and without CSPH.

Insulin resistance in patients with cirrhosis and portal hypertension

Insulin resistance (IR) is involved in the pathogenesis of endothelial dysfunction and is also present in patients with cirrhosis. Intrahepatic endothelial dysfunction plays a major role, increasing hepatic vascular resistance and promoting portal hypertension (PH). In addition, β-adrenergic agonists and insulin share several intracellular signaling pathways. Thus IR may influence the response to β-blockers. This study aimed at evaluating the relationship between IR and hepatic hemodynamics in patients with cirrhosis and with the portal pressure response to acute β-blockade. Forty-nine patients with cirrhosis and PH were included. Hepatic and systemic hemodynamics were measured, and IR was estimated by using the updated homeostasis model assessment (HOMA)-2 index. Patients with HOMA-2 > 2.4 were considered IR. In patients with hepatic venous pressure gradient (HVPG) ≥ 10 mmHg) [clinically significant PH (CSPH)], hemodynamic measurements were performed again 20 min after intravenous propranolol. Mean HOMA-2 index was 3 ± 1.4. Fifty-seven percent of patients had IR. A weak correlation between HOMA-2 index and HVPG was observed. Eighty-six percent of patients had CSPH. HOMA-2 index was an independent predictor of CSPH. However, in patients with CSPH, the correlation between HOMA-2 index and HVPG was lost. HVPG, but not IR, predicted the presence of esophageal varices. Response to propranolol was not different between patients with or without IR. In nondiabetic patients with cirrhosis, HOMA-2 index is directly associated with the presence of CSPH and indirectly with varices, but does not allow either grading HVPG or predicting its response to propranolol.

PPARα activation improves endothelial dysfunction and reduces fibrosis and portal pressure in cirrhotic rats

BACKGROUND & AIMS

Peroxisome proliferator-activated receptor α (PPARα) is a transcription factor activated by ligands that regulates genes related to vascular tone, oxidative stress, and fibrogenesis, pathways implicated in the development of cirrhosis and portal hypertension. This study aims at evaluating the effects of PPARα activation with fenofibrate on hepatic and systemic hemodynamics, hepatic endothelial dysfunction, and hepatic fibrosis in CCl(4)-cirrhotic rats.

METHODS

Mean arterial pressure (MAP), portal pressure (PP), and portal blood flow (PBF) were measured in cirrhotic rats treated with oral fenofibrate (25mg/kg/day, n=10) or its vehicle (n=12) for 7 days. The liver was then perfused and dose-relaxation curves to acetylcholine (Ach) were performed. We also evaluated Sirius Red staining of liver sections, collagen-I mRNA expression, and smooth muscle actin (α-SMA) protein expression, cyclo-oxygenase-1 (COX-1) protein expression, and cGMP levels in liver homogenates, and TXB(2) production in perfusates. Nitric oxide (NO) bioavailability and eNOS activation were measured in hepatic endothelial cells (HEC) isolated from cirrhotic rat livers.

RESULTS

CCl(4) cirrhotic rats treated with fenofibrate had a significantly lower PP (-29%) and higher MAP than those treated with vehicle. These effects were associated with a significant reduction in hepatic fibrosis and improved vasodilatory response to acetylcholine. Moreover, a reduction in COX-1 expression and TXB(2) production in rats receiving fenofibrate and a significant increase in NO bioavailability in HEC with fenofibrate were observed.

CONCLUSIONS

PPARα activation markedly reduced PP and liver fibrosis and improved hepatic endothelial dysfunction in cirrhotic rats, suggesting it may represent a new therapeutic strategy for portal hypertension in cirrhosis.

Non-selective β-blockers improve the correlation of liver stiffness and portal pressure in advanced cirrhosis

BACKGROUND

Liver stiffness (LS) correlates with portal pressure (hepatic venous pressure gradient, HVPG). However, the dynamic components of portal hypertension (PHT) in advanced cirrhosis may not be adequately assessed by TE. The influence of treatment with non-selective β-blockers (NSBB) on the correlation of HVPG and LS has not been investigated.

METHODS

One hundred and twenty-two patients with esophageal varices were included. LS, hemodynamic parameters, and HVPG were recorded at baseline (BL) and after 6 weeks of treatment with NSBB (FU). The correlation of LS and HVPG was compared to control patients with HVPG ≤ 12 mmHg.

RESULTS

Patients with higher Child-Pugh stages (A:88/B:25/C:9) had higher levels of liver stiffness (47.4 ± 16.5 vs. 70.3 ± 7.9 vs. 73.7 ± 2.1 kPa) and HVPG (21 ± 5 vs. 26 ± 5 vs. 26 ± 4 mmHg). The correlation of LS and HVPG was stronger in controls with HVPG ≤ 12 mmHg (R = 0.951; P < 0.0001) than in patients with HVPG > 12 mmHg (R = 0.538; P = 0.0004). The association of HVPG with LS became stronger under treatment with NSBB, which finally restored the linear correlation of HVPG and LS (R = 0.930; P < 0.0001). Forty-three percent (53/122) of patients were hemodynamic responders to NSBB. The improvement in the correlation of LS and HVPG under NSBB was mainly noted in hemodynamic responders (R = 0.864), but not in nonresponders (R = 0.535), whereas changes in LS, heart rate, and MAP were similar in responders and nonresponders.

CONCLUSIONS

Targeting the hyperdynamic circulation and the increased splanchnic blood inflow by treatment with NSBB unmasks the linear (mechanical) correlation of HVPG and LS in patients with HVPG > 12 mmHg. Measurement of LS by TE is not a feasible method to assess the dynamic components of PHT.

Normal and altered three-dimensional portal venous hemodynamics in patients with liver cirrhosis

PURPOSE

To compare time-resolved three-dimensional (3D) phase-contrast magnetic resonance (MR) imaging with three-directional velocity encoding (flow-sensitive four-dimensional [4D] MR imaging), with Doppler ultrasonography (US) as standard of reference, for investigating alterations in 3D portal venous hemodynamics in patients with liver cirrhosis compared with healthy age-matched control subjects and healthy young volunteers.

MATERIAL & METHODS

This prospective study was approved by the local ethics committee, and written informed consent was obtained from all participants. Three-dimensional portal venous hemodynamics was assessed, employing flow-sensitive 4D MR imaging with a 3-T MR system (spatial resolution, approximately 2 mm(3); temporal resolution, approximately 45 msec) in 20 patients with hepatic cirrhosis, 20 healthy age-matched control subjects, and 21 healthy young volunteers. Flow characteristics were analyzed by using 3D streamlines and time-resolved particle traces. Quantitative analyses were performed by retrospectively evaluating regional peak and mean velocities, flow volume, and vessel area. Doppler US was used as standard of reference. Independent-sample t tests or Wilcoxon-Mann-Whitney tests were applied for comparing each subject group. Paired-sample t tests or Wilcoxon tests were applied when comparing MR imaging and US.

RESULTS

Three-dimensional visualization of portal venous hemodynamics was successful, with complete visualization of the vessels in 18 patients and 35 volunteers, with limitations in the left intrahepatic branches (87%, reader A; 89%, reader B). A moderate but significant correlation was observed between 4D MR imaging and Doppler US in nearly all maximum and mean velocities, flow volumes, and vessel areas (r = 0.24-0.64, P = .001-.044). With MR imaging, significant underestimation was observed of intrahepatic flow velocities and flow volumes, except vessel area, which Doppler US represented as even lower (P < .001 to P = .045). Six patients had collateralization with reopened umbilical vein, while one had flow reversal in the superior mesenteric vein visible at MR imaging only.

CONCLUSION

Flow-sensitive 4D MR imaging may constitute a promising, alternative technique to Doppler US for evaluating hemodynamics in the portal venous system of patients with liver cirrhosis and may be a means of assessing pathologic changes in flow characteristics.

Does the model for end-stage liver disease score predict transfusion amount, acid-base imbalance, haemodynamic and oxidative abnormalities during living donor liver transplantation?

The model for end-stage liver disease (MELD) score is associated with the severity of liver failure in transplant patients. This study examined whether life-threatening stress factors during liver transplantation differed according to the patients' preoperative MELD scores. Forty-four patients who underwent living donor liver transplantation were divided into a high MELD group (MELD score ≥ 20) (n = 25) and a low MELD group (MELD score < 20) (n = 19). The volume of blood components transfused, acid-base homeostasis variables, and haemodynamic and oxidative variables were measured at each stage of the surgery. The systemic vascular resistance index was significantly lower in the high MELD group than in the low MELD group at all time points. The oxygen utility index and the oxygen extraction ratio were all significantly lower in the high MELD group than in the low MELD group only at the preanhepatic stage and not at later stages of surgery. Intraoperative transfusion volume and the severity of metabolic acidosis were not associated with the preoperative MELD score.

Spironolactone lowers portal hypertension by inhibiting liver fibrosis, ROCK-2 activity and activating NO/PKG pathway in the bile-duct-ligated rat

OBJECTIVE

Aldosterone, one of the main peptides in renin angiotensin aldosterone system (RAAS), has been suggested to mediate liver fibrosis and portal hypertension. Spironolactone, an aldosterone antagonist, has beneficial effect on hyperdynamic circulation in clinical practice. However, the mechanisms remain unclear. The present study aimed to investigate the role of spionolactone on liver cirrhosis and portal hypertension.

METHODS

Liver cirrhosis was induced by bile duct ligation (BDL). Spironolactone was administered orally (20 mg/kg/d) after bile duct ligation was performed. Liver fibrosis was assessed by histology, Masson's trichrome staining, and the measurement of hydroxyproline and type I collagen content. The activation of HSC was determined by analysis of alpha smooth muscle actin (α-SMA) expression. Protein expressions and protein phosphorylation were determined by immunohistochemical staining and Western blot analysis, Messenger RNA levels by quantitative real time polymerase chain reaction (Q-PCR). Portal pressure and intrahepatic resistance were examined in vivo.

RESULTS

Treatment with spironolactone significantly lowered portal pressure. This was associated with attenuation of liver fibrosis, intrahepatic resistance and inhibition of HSC activation. In BDL rat liver, spironolactone suppressed up-regulation of proinflammatory cytokines (TNFα and IL-6). Additionally, spironolactone significantly decreased ROCK-2 activity without affecting expression of RhoA and Ras. Moreover, spironolactone markedly increased the levels of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS and the activity of NO effector-protein kinase G (PKG) in the liver.

CONCLUSION

Spironolactone lowers portal hypertension by improvement of liver fibrosis and inhibition of intrahepatic vasoconstriction via down-regulating ROCK-2 activity and activating NO/PKG pathway. Thus, early spironolactone therapy might be the optional therapy in cirrhosis and portal hypertension.

The effects of sorafenib on the portal hypertensive syndrome in patients with liver cirrhosis and hepatocellular carcinoma--a pilot study

BACKGROUND

Increased intrahepatic vascular resistance and hyperperfusion in the splanchnic circulation are the principal mechanisms leading to portal hypertension in cirrhosis. Several preclinical studies have demonstrated a beneficial effect of the multikinase inhibitor sorafenib on the portal hypertensive syndrome.

AIM

To investigate the effect of sorafenib on hepatic venous pressure gradient (HVPG), systemic hemodynamics and intrahepatic mRNA expression of proangiogenic, profibrogenic and proinflammatory genes.

METHODS

Patients with liver fibrosis/cirrhosis and hepatocellular carcinoma were treated with sorafenib 400 mg b.d. HVPG measurement and transjugular liver biopsy were performed at baseline and at week 2. Changes in HVPG and intrahepatic mRNA expression of vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), RhoA, tumour necrosis factor-alpha (TNF-α) and placental growth factor (PlGF) were evaluated.

RESULTS

Thirteen patients (m/f = 12/1; Child-Pugh class A/B = 10/3) were included. The most common aetiology of liver disease was alcohol consumption (n = 7). Eleven patients had an elevated portal pressure, including eight patients with clinically significant portal hypertension. A significant decrease of HVPG (≥ 20% from baseline) was observed in four subjects. In HVPG responders, we observed mRNA downregulation of VEGF, PDGF, PlGF, RhoA kinase and TNF-α, while no substantial mRNA decrease was found in nonresponders in any of the five genes. In two of the four HVPG responders we observed a dramatic (43-85%) mRNA decrease of all five investigated genes.

CONCLUSION

Larger controlled clinical trials are needed to demonstrate any potential beneficial effect of sorafenib on portal hypertension in patients with cirrhosis.

Noninvasive evaluation of portal hypertension: emerging tools and techniques

Portal hypertension is the main cause of complications in patients with cirrhosis. However, evaluating the development and progression of portal hypertension represents a challenge for clinicians. There has been considerable focus on the potential role of noninvasive markers of portal hypertension that could be used to stratify patients with respect to the stage of portal hypertension and to monitor disease progression or treatment response in a longitudinal manner without having to undertake repeated invasive assessment. The pathogenesis of portal hypertension is increasingly understood and emerging knowledge of the vascular processes that underpin portal hypertension has paved the way for exploring novel biomarkers of vascular injury, angiogenesis, and endothelial dysfunction. In this paper we focus on the pathogenesis of portal hypertension and potential non-invasive biomarkers with particular emphasis on serum analytes.

The utility of scoring systems in predicting early and late mortality in alcoholic hepatitis: whose score is it anyway?

Background. Alcoholic hepatitis (AH) is a distinct clinical entity in the spectrum of alcoholic liver disease with a high short-term mortality. Several scoring systems are being used to assess the severity of AH but the ability of these scores to predict long-term survival in these patients is largely unknown. Aims. We aim to assess the utility of five different scoring systems Child Pugh (CP), model for end-stage liver disease (MELD), Maddrey's discriminant function (mDF), Glasgow AH score (GAHS), and age-bilirubin-INR-creatinine (ABIC) score in predicting shot-term and long-term survival in patients with AH. Methods. Patients with histological evidence of AH were identified from our database. The clinical and biochemical parameters were used to calculate the 5 different scores. The prognostic utility of these scores was determined by generating an ROC curve for survival at 30 days, 90 days, 6 months, and 1 year. Results and Conclusions. All 5 scores with the exception of CP score have a similar accuracy in predicting the short-term prognosis. However, they are uniformly poor in predicting longer-term survival with AUROC not exceeding 0.74. CP score is a very poor predictor of survival in both short and long term. Abstinence from alcohol was significantly (P < 0.05) associated with survival at 1 year.

Pathophysiology of portal hypertension and esophageal varices

Esophageal varices are the major complication of portal hypertension. It is detected in about 50% of cirrhosis patients, and approximately 5-15% of cirrhosis patients show newly formed varices or worsening of varices each year. The major therapeutic strategy of esophageal varices consists of primary prevention, treatment for bleeding varices, and secondary prevention, which are provided by pharmacological, endoscopic, interventional and surgical treatments. Optimal management of esophageal varices requires a clear understanding of the pathophysiology and natural history. In this paper, we outline the current knowledge and future prospect in the pathophysiology of esophageal varices and portal hypertension.

MELD-based indices as predictors of mortality in chronic liver disease patients who undergo emergency surgery with general anesthesia

BACKGROUND

Underlying chronic liver disease is associated with high morbidity and mortality after emergency surgery, which complicates clinical decisions over performing such surgery. In addition, the Child-Turcotte-Pugh (CTP) score is limited in its ability to predict postoperative residual liver function. This study was designed to determine whether the scores of the Model for End-stage Liver Disease (MELD)-based indices are effective predictors of mortality following emergency surgery in patients with chronic liver disease.

METHOD

Medical records of 53 chronic liver disease patients who underwent emergency surgery under general anesthesia from 2001 to 2008 were analyzed retrospectively.

RESULTS

Median preoperative CTP score was 6 (5-12); MELD, 11 (6-33); MELD-Na, 15 (7-34); integrated MELD (iMELD), 33 (14-64); and MELD to sodium ratio, 8 (4-24). During a median 11-month follow-up period, 19 (35.8%) patients died. Five of them (26.3%) had operative mortality (i.e., mortality within 30 days after surgery). On multivariate analysis, CTP class C was correlated with operative mortality, and estimated blood loss above 300 ml and the iMELD score above 35 were significantly correlated with overall mortality.

CONCLUSIONS

iMELD reflects underlying liver function and predicts overall mortality more accurately than CTP and other MELD-based indices scores do in chronic liver disease patients after emergency surgery with general anesthesia.

[Spontaneous visits to the emergency service and hepatology day hospital by patients with liver cirrhosis]

INTRODUCTION

Because of the current overload of emergency services, new units, such as day units, have had to be created. Liver cirrhosis (LC) is a chronic disease with frequent decompensations requiring medical attention. The aim of this study was to compare differences between emergency consultations in a hepatology day hospital (HDH) and in an emergency service (ES) among patients with LC.

METHODS AND MATERIAL

We performed an observational prospective study. All patients with LC attending the HDH or ES from September 2007 to August 2008 were asked to complete a questionnaire. Demographic, clinical, and radiological variables were collected.

RESULTS

There were 743 consultations, of which 62% involved the HDH. The mean age was 65±12 years, and the male/female ratio was 2:3. The most frequent diagnosis in the ES was hepatic encephalopathy (26.2% ES versus 6% HDH, p<0.001) followed by upper gastrointestinal hemorrhage (17.7% ES versus 0.6% HDH, p<0.001), while the most frequent diagnosis in the HDH was ascites (66.2% HDH versus 22.7% ES, p<0.001). The tests performed were as follows: blood analysis: 95% ES versus 60% HDH (p<0.01); radiology: 71% ES versus 11% HDH (p<0.01) and paracentesis: 51% ES versus 74% HDH (p<0.01). The mean length of stay in the ES was 21.3±121.5 hours compared with 3.3±2.4 hours in the HDH (p<0.001). A total of 53% of patients attended in the ES were hospitalized compared with 12% of those attended in the HDH (p<0.05).

CONCLUSION

Patients with LC preferentially attend the HDH, where fewer tests are performed and the length of stay is shorter. The care provided in the HDH is appropriate and efficient.

11,12-EET increases porto-sinusoidal resistance and may play a role in endothelial dysfunction of portal hypertension

CYP450-dependent epoxyeicosatrienoic acids (EETs) are potent arterial vasodilators, while 20-hydroxyeicosatatraenoic acid (20-HETE) is a vasoconstrictor. We evaluated their role in the control of portal circulation in normal and cirrhotic (CCl(4) induced) isolated perfused rat liver. Phenylephrine (PE) and endothelin-1 (ET-1) increased portal perfusion pressure, as did arachidonic acid (AA), 20-HETE, and 11,12-EET. Inhibition of 20-HETE with 12,12-dibromododecenoic acid (DBDD) did not affect basal pressure nor the responses to PE, ET-1, or AA. However, inhibition of epoxygenase with miconazole caused a significant reduction in the response to ET-1 and to AA, without affecting neither basal pressure nor the response to PE. Hepatic vein EETs concentration increased in response to ET-1, and was increased in cirrhotic, compared to control, livers. 20HETE levels were non-measurable. Miconazole decreased portal perfusion pressure in cirrhotic livers. In conclusion, 20HETE and EETs increase portal resistance; EETs, but not 20-HETE, mediate in part the pressure response to ET-1 in the portal circulation and may be involved in pathophysiology of portal hypertension.

Acute-on-chronic liver failure: current concepts on definition, pathogenesis, clinical manifestations and potential therapeutic interventions

In recent years, acute-on-chronic liver failure has been recognized as a specific clinical form of liver failure associated with cirrhosis. The syndrome refers to an acute deterioration of liver function and subsequently of other end organs over a period of weeks following a precipitating event in a patient with previously well- or reasonably well-compensated cirrhosis. These precipitating events include either an indirect (e.g., variceal hemorrhage, sepsis) or a direct (e.g., drug-induced) hepatotoxic factor. The short-term mortality for this condition is more than 50%. At present, considerable efforts are ongoing to better characterize the syndrome, to gain further insight into its pathophysiology and to optimize therapy. This article aims to highlight the current concepts of these various aspects.

Feasibility and safety of percutaneous coronary intervention in patients with end-stage liver disease referred for liver transplantation

Percutaneous coronary intervention (PCI) has traditionally not been an option for patients with end-stage liver disease (ESLD) and coronary artery disease (CAD). This retrospective study was designed to demonstrate the feasibility and safety of PCI in liver transplant candidates. Patients with ESLD and hemodynamically significant CAD who were otherwise deemed to be acceptable candidates for liver transplantation underwent PCI. The procedural success rates, mortality and myocardial infarction rates, and bleeding outcomes were examined. Sixteen patients with ESLD underwent PCI: 15 with bare-metal stents (1.3 stents per patient on average) and 1 with balloon angioplasty alone. The median diameter stenosis per lesion was 80%, the median platelet count was 68 × 10(9) /L, the median international normalized ratio was 1.3, and the median Model for End-Stage Liver Disease score was 13. PCI was successful in 94% of the patients. One patient had a suboptimal residual stenosis of 50% after stenting. There were no in-hospital or 30-day deaths or myocardial infarctions, and no patients developed hematomas. One patient required a 1-U platelet transfusion, and another required 1 U of packed red blood cells. All patients remained clinically stable 1 month after PCI. Nine of the 16 patients were listed for liver transplantation, and 3 patients underwent liver transplantation. In conclusion, we have demonstrated the safety and feasibility of PCI in a small cohort of patients with ESLD and hemodynamically significant CAD, the majority of whom had significant thrombocytopenia. Larger studies are required to determine whether PCI is an effective treatment strategy for patients with ESLD and hemodynamically significant CAD who otherwise would not be candidates for liver transplantation.

Portal pressure predicts outcome and safety of antiviral therapy in cirrhotic patients with hepatitis C virus infection

BACKGROUND & AIMS

There are limited data on the efficacy and safety of antiviral therapy in patients with hepatitis C virus (HCV)-related cirrhosis, particularly on the impact of portal hypertension.

METHODS

We assessed hepatovenous pressure gradient (HVPG), liver stiffness (transient elastography), and interleukin (IL)-28B polymorphisms (rs12979860) in 90 cirrhotic patients with HCV infection (82% genotype 1 or 4) before antiviral therapy with pegylated interferon and ribavirin. Efficacy and safety were evaluated.

RESULTS

Rates of sustained virologic response were significantly lower among patients with clinically significant portal hypertension (CSPH; HVPG ≥ 10 mm Hg; n = 50) than among patients without CSPH (HVPG <10 mm Hg; n = 40): 14% vs 51% (P = .0007). Seventy-nine percent and 83% of patients with CSPH and without CSPH, respectively, received more than 80% of planned dose (P = .647). The predictive value of HVPG (area under the curve [AUC], 0.743) was greater than that of liver stiffness (AUC, 0.647) or of baseline HCV RNA levels (AUC, 0.620). The IL-28B polymorphism was not associated significantly with a sustained virologic response. Multivariate analysis revealed that HVPG (odds ratio [OR], 14.3; P = .009), baseline HCV RNA levels (OR, 5.3; P = .019), and HCV genotype (OR, 6.5; P = .046) were independent risk factors for treatment failure. A trend toward higher incidence of anemia and neutropenia was observed for patients with CSPH. The incidence and grade of thrombocytopenia were significantly higher among patients with than without CSPH (94% vs 75%; P = .006).

CONCLUSIONS

HVPG is an independent predictor of response to antiviral therapy, with better predictive value than liver stiffness, baseline HCV RNA levels, HCV genotype, or IL-28B polymorphism. The incidence and grade of thrombocytopenia during antiviral therapy are higher among patients with CSPH. In evaluating cirrhotic HCV patients for antiviral treatment, measurement of HVPG should be considered.

Portal hypertension correlates with splenic stiffness as measured with MR elastography

PURPOSE

To investigate the correlation between MR elastography (MRE) assessed spleen stiffness and direct portal vein pressure gradient (D-HVPG) measurements in a large animal model of portal hypertension.

MATERIALS AND METHODS

Cholestatic liver disease was established in adult canines by common bile duct ligation. A spin echo based echo planar imaging (EPI) MRE sequence was used to acquire three-dimensional/three axis (3D/3-axis) abdominal MRE data at baseline, 4 weeks, and 8 weeks. Liver biopsies, blood samples, and D-HVPG measurements were obtained simultaneously.

RESULTS

Animals developed portal hypertension (D-HVPG: 11.0 ± 5.1 mmHg) with only F1 fibrosis after 4 weeks. F3 fibrosis was confirmed after 8 weeks despite no further rise in portal hypertension (D-HVPG: 11.3 ± 3.2 mmHg). Mean stiffnesses of the spleen increased over two-fold from baseline (1.72 ± 0.33 kPa) to 4 weeks (3.54 ± 0.31 kPa), and stabilized at 8 weeks (3.38 ± 0.06 kPa) in a pattern consistent with changes in portal pressure. A positive correlation was observed between spleen stiffness and D-HVPG (r(2) = 0.86; P < 0.01).

CONCLUSION

These findings indicate a temporal relationship between portal hypertension and the development of liver fibrosis in a large animal model of cholestatic liver disease. The observed direct correlation between spleen stiffness and D-HVPG suggest a noninvasive MRE approach to diagnose and screen for portal hypertension.

The heart in liver transplantation

The heart and liver are organs that are closely related in both health and disease. Patients who undergo liver transplantation may suffer from heart disease that is: (a) related to the original cause of the liver disease such as hemochromatosis, (b) related to the liver disease itself, or (c) related to other associated conditions. Furthermore, liver transplantation is one of the most cardiovascular stressful events that a patient with cirrhosis may undergo. After liver transplantation, the progression of pre-existing or the development of new-onset cardiac disease may occur. This article reviews the relationship between the heart and liver transplantation in the pre-transplant, intra-operative, and post-transplant periods.

Tempol administration, a superoxide dismutase mimetic, reduces hepatic vascular resistance and portal pressure in cirrhotic rats

BACKGROUND & AIMS

Increased superoxide in cirrhotic livers, by reducing nitric oxide bioavailability, contributes to increase intrahepatic vascular resistance to portal blood flow and as a consequence portal pressure. We aimed to evaluate whether a strategy directed to reduce superoxide using tempol, a small membrane permeable SOD-mimetic, is able to modulate intrahepatic nitric oxide content and reduce portal pressure in cirrhotic rats.

METHODS

Superoxide and nitric oxide were evaluated in control sinusoidal endothelial cells (SEC) pre-treated with the pro-oxidant diethyldithiocarbamate (DDC) and in CCl(4)-cirrhotic rat livers treated with tempol or vehicle. Mean arterial pressure, portal pressure, and portal blood flow were measured in control and cirrhotic rats treated with tempol (180μmol/kg/h; via ileocholic vein) or vehicle. In a subset of animals, hemodynamic measurements were performed after NO-inhibition with l-NAME.

RESULTS

Tempol reduced superoxide content and increased NO both in SEC and cirrhotic livers. In cirrhotic rats, but not in controls, tempol significantly reduced portal pressure, and increased portal blood flow, which most likely reflects a reduction in intrahepatic vascular resistance. Tempol significantly reduced mean arterial pressure. l-NAME prevented all these effects.

CONCLUSIONS

Tempol reduces superoxide, increases nitric oxide, and reduces portal pressure in sinusoidal endothelial cells and in cirrhotic livers. These results confirm that oxidative stress has a role in the pathogenesis of portal hypertension and supports the use of antioxidants in its treatment. However, when considering the use of antioxidants as additional therapy to treat portal hypertension, the potential to produce deleterious effects on systemic hemodynamics needs to be carefully evaluated.

Outcome predictors of cirrhotic patients with spontaneous bacterial empyema

BACKGROUND

Spontaneous bacterial empyema (SBE) is a complication of cirrhotic patients in which a pre-existing pleural effusion becomes infected. This retrospective study was designed to investigate the bacteriology and outcome predictors of SBE in cirrhotic patients.

METHODS

Medical records of cirrhotic patients treated in a tertiary care university hospital from December 2004 to December 2008 were retrospectively reviewed.

RESULTS

Of 3390 cirrhotic patients seen during the study period, 81 cases of SBE were diagnosed. The incidence of SBE was 2.4% (81/3390) in cirrhotic patients and 16% (81/508) in patients with cirrhosis with hydrothorax. There were 46 monomicrobial infections found in 46 SBE patients. Aerobic Gram-negative organisms were the predominant pathogens (n=29, 63%), and Escherichia coli (n=9, 20%) was the most frequently isolated sole pathogen. The mortality rate of SBE was 38% (31/81). Univariate analysis showed that Child-Pugh score, model for end-stage liver disease (MELD)-Na score, concomitant bacteraemia, concomitant spontaneous bacterial peritonitis, initial intensive care unit (ICU) admission and initial antibiotic treatment failure were predictors of poor outcomes. Multivariate regression analysis demonstrated that the independent factors related to a poor outcome were initial ICU admission [odds ratio (OR): 4.318; 95% confidence interval 1CI) 1.09-17.03; P=0.037], MELD-Na score (OR: 1.267; 95% CI 1.08-1.49; P=0.004) and initial antibiotic treatment failure (OR: 13.10; 95% CI 2.60-66.03).

CONCLUSION

Spontaneous bacterial empyema in cirrhotic patients is a high mortality complication. The independent factors related to poor outcome are high MELD-Na score, initial ICU admission and initial antibiotic treatment failure. High MELD-Na score may be a useful mortality predictor of SBE in cirrhotic patients.

Noncirrhotic human nonalcoholic fatty liver disease induces portal hypertension in relation to the histological degree of steatosis

INTRODUCTION

We earlier showed in an animal model that steatosis, in the absence of fibrosis or inflammation, induces a significant rise in portal pressure. The relevance of these findings for human pathology is unknown till date.

AIMS

To study portal pressure in nonalcoholic fatty liver disease patients and to identify factors possibly related to steatosis-induced changes in liver haemodynamics.

MATERIALS AND METHODS

Patients presenting with a problem of overweight and with noninvasive signs of liver involvement were proposed for transjugular liver biopsy. The biopsy was scored according to the Nonalcoholic Steatohepatitis Clinical Research Network scoring system.

RESULTS

Fifty consecutive patients were studied. Mean age was 47.9 ± 13.6 years; 31 (62%) of them were female. Hepatic venous pressure gradient (HVPG) was normal in 27 patients (54%), borderline (5 mmHg) in nine (18%) and elevated in 14 patients (28%). For further analysis those with a HVPG of 5 mmHg were considered normal (group 1). HVPG was 8.8 ± 2.6 mmHg in those with an elevated HVPG (group 2) versus 3.4 ± 1.2 mmHg in group 1 (P < 0.0001). In both the groups, only one patient had cirrhosis; 26 of 36 (group 1) and nine of 14 patients (group 2) had fibrosis score 0. Fibrosis score was not significantly different (P = 0.530). Perisinusoidal fibrosis score was not significantly different (P = 0.186). Steatosis was the only histological feature that significantly differed between the groups (P = 0.016). The degree of steatosis (P = 0.010) was the only independent predictor of the presence of portal hypertension.

CONCLUSION

Human nonalcoholic fatty liver disease can, even in the absence of significant fibrosis, induce portal hypertension, correlated with the severity of the steatosis.

Bacterial DNA translocation is associated with systemic circulatory abnormalities and intrahepatic endothelial dysfunction in patients with cirrhosis

Presence of bacterial DNA in noninfected patients with cirrhosis and ascites is associated with a marked inflammatory response including activation of the inducible form of nitric oxide synthase and release of nitric oxide, similar to that observed in patients with spontaneous bacterial peritonitis. Although presence of bacterial DNA is associated with an impaired prognosis, no information is available regarding its hemodynamic consequences. Systemic and hepatic hemodynamics before and after a liquid test meal were assessed in a series of 75 noninfected patients with cirrhosis (55 with ascites). Bacterial DNA was measured by polymerase chain reaction. Bacterial DNA was detected only in patients with ascites. Clinical data and liver function were similar in ascitic patients with presence (n = 21) or absence of bacterial DNA (n = 34). Bacterial-DNA(+) patients had significantly lower mean arterial pressure (P = 0.002) and systemic vascular resistance (P = 0.03) than bacterial-DNA(-) patients. Cardiac output, cardiopulmonary pressures, hepatic venous pressure gradient (HVPG), and hepatic blood flow were similar in both groups. Thirty minutes after the test meal, in response to increased blood flow caused by postprandial hyperemia, there was a significantly greater increase in HVPG and impaired hepatic vasorelaxation in bacterial-DNA(+) as compared with bacterial-DNA(-) patients, which indicates hepatic endothelial dysfunction. Indeed, the increase in HVPG after the test meal significantly correlated with serum bacterial DNA concentration.

CONCLUSION

Presence of bacterial DNA, a marker of bacterial translocation, is associated with aggravation of peripheral vasodilation and with worsening of intrahepatic endothelial dysfunction.

Acute esophageal variceal bleeding: Current strategies and new perspectives

Management of acute variceal bleeding has greatly improved over recent years. Available data indicates that general management of the bleeding cirrhotic patient by an experienced multidisciplinary team plays a major role in the final outcome of this complication. It is currently recommended to combine pharmacological and endoscopic therapies for the initial treatment of the acute bleeding. Vasoactive drugs (preferable somatostatin or terlipressin) should be started as soon as a variceal bleeding is suspected (ideally during transfer to hospital) and maintained afterwards for 2-5 d. After stabilizing the patient with cautious fluid and blood support, an emergency diagnostic endoscopy should be done and, as soon as a skilled endoscopist is available, an endoscopic variceal treatment (ligation as first choice, sclerotherapy if endoscopic variceal ligation not feasible) should be performed. Antibiotic prophylaxis must be regarded as an integral part of the treatment of acute variceal bleeding and should be started at admission and maintained for at least 7 d. In case of failure to control the acute bleeding, rescue therapies should be immediately started. Shunt therapies (especially transjugular intrahepatic portosystemic shunt) are very effective at controlling treatment failures after an acute variceal bleeding. Therapeutic developments and increasing knowledge in the prognosis of this complication may allow optimization of the management strategy by adapting the different treatments to the expected risk of complications for each patient in the near future. Theoretically, this approach would allow the initiation of early aggressive treatments in high-risk patients and spare low-risk individuals unnecessary procedures. Current research efforts will hopefully clarify this hypothesis and help to further improve the outcomes of the severe complication of cirrhosis.

Increased plasma malondialdehyde in patients with viral cirrhosis and its relationships to plasma nitric oxide, endotoxin, and portal pressure

BACKGROUND AND AIM

Increased oxidative stress is involved in the development of portal hypertension in cirrhosis. Our study aimed to assess the relationship between oxidative stress and hemodynamic parameters in cirrhotic patients.

METHODS

Forty-two patients with viral cirrhosis and 24 normal controls were enrolled. Measurements of plasma levels of malondialdehyde (MDA), nitrite/nitrate (NOx), endotoxin, and activities of superoxide dismutase (SOD) were carried out in all subjects. Systemic and splanchnic hemodynamic measurements were carried out in cirrhotic patients.

RESULTS

Plasma levels of MDA, endotoxin, and NOx were significantly higher in cirrhotic patients than in normal controls (900 +/- 751 versus 226 +/- 16 nM, P < 0.01; 62.0 +/- 26.0 versus 14.8 +/- 4.1 pg/mL, P < 0.01; 50.5 +/- 22.6 versus 15.0 +/- 9.2 nM, P < 0.01, respectively). Activities of SOD were significantly decreased in cirrhotic patients compared with in normal controls (2.62 +/- 0.7 versus 6.8 +/- 0.4 U/mL). Further, plasma levels of MDA in cirrhotic patients were significantly positively associated with hepatic venous pressure gradient (HVPG) (r = 0.35; P = 0.025), wedge hepatic venous pressure (WHVP) (r = 0.42; P = 0.007), and hepatic sinusoid resistance (HSR) (r = 0.33; P = 0.033). Plasma MDA levels also correlated positively with plasma endotoxin (r = 0.71, P < 0.001) and NOx (r = 0.55, P < 0.001) levels in the cirrhotic patients. Multiregression analysis showed that the independent and strongest factors to predict HVPG, WHVP, and HSR are plasma levels of NOx, MDA, and endotoxin, respectively.

CONCLUSION

This study suggests a close interaction among MDA, endotoxin, and NOx and that these substances are also associated with hemodynamic derangement in cirrhosis.

Physiopathology of splanchnic vasodilation in portal hypertension

In liver cirrhosis, the circulatory hemodynamic alterations of portal hypertension significantly contribute to many of the clinical manifestations of the disease. In the physiopathology of this vascular alteration, mesenteric splanchnic vasodilation plays an essential role by initiating the hemodynamic process. Numerous studies performed in cirrhotic patients and animal models have shown that this splanchnic vasodilation is the result of an important increase in local and systemic vasodilators and the presence of a splanchnic vascular hyporesponsiveness to vasoconstrictors. Among the molecules and factors known to be potentially involved in this arterial vasodilation, nitric oxide seems to have a crucial role in the physiopathology of this vascular alteration. However, none of the wide variety of mediators can be described as solely responsible, since this phenomenon is multifactorial in origin. Moreover, angiogenesis and vascular remodeling processes also seem to play a role. Finally, the sympathetic nervous system is thought to be involved in the pathogenesis of the hyperdynamic circulation associated with portal hypertension, although the nature and extent of its role is not completely understood. In this review, we discuss the different mechanisms known to contribute to this complex phenomenon.

HIV-HCV co-infected patients with low CD4+ cell nadirs are at risk for faster fibrosis progression and portal hypertension

Patients co-infected with the human immunodeficiency virus (HIV) and the hepatitis C virus (HCV) are fraught with a rapid fibrosis progression rate and with complications of portal hypertension (PHT) We aimed to assess the influence of immune function [Centers of Disease Control and Prevention (CDC) stage] on development of PHT and disease progression in HIV-HCV co-infection. Data of 74 interferon-naïve HIV-HCV co-infected patients undergoing liver biopsy, measurement of portal pressure and of liver stiffness and routine laboratory tests (including CD4+ cell count, HIV and HCV viral load) were analysed. Time of initial exposure (risk behaviour) was used to assess fibrosis progression. Fibrosis progression, time to cirrhosis and portal pressure were correlated with HIV status (CDC stage). HIV-HCV patients had rapid progression of fibrosis [0.201 +/- 0.088 METAVIR fibrosis units/year (FU/y)] and accelerated time to cirrhosis (24 +/- 13 years), high HCV viral loads (4.83 x 10(6) IU/mL) and a mean HVPG at the upper limit of normal (5 mmHg). With moderate or severe immunodeficiency, fibrosis progression was even higher (CDC-2 = 0.177 FU/y; CDC-3 = 0.248 FU/y) compared with patients with higher CD4+ nadirs (CDC-1 = 0.120 FU/y; P = 0.0001). An indirect correlation between CD4+ cell count and rate of fibrosis progression (R = -0.6654; P < 0.001) could be demonstrated. Hepatic venous pressure gradient (HVPG) showed early elevation of portal pressure with median values of 4, 8 and 12 mmHg after 10, 15 and 20 years of HCV infection for CDC-3 patients. Patients treated with highly active anti-retroviral therapy (HAART) had similar rates of progression and portal pressure values than patients without HAART. Progression of HCV disease is accelerated in HIV-HCV co-infection, being more pronounced in patients with low CD4+ cell count. A history of a CD4+ cell nadir <200/microL is a risk factor for rapid development of cirrhosis and PHT. Thus, HCV treatment should be considered early in patients with HIV-HCV co-infection and largely preserved CD4+ cell counts.

Administration of a low dose of sildenafil for 1 week decreases intrahepatic resistance in rats with biliary cirrhosis: the role of NO bioavailability

Increasing NO bioavailability improves hepatic endothelial dysfunction, which ameliorates intrahepatic resistance and portal hypertension. Acute administration of sildenafil increases hepatic production of NO with a reduction in hepatic sinusoid resistance in cirrhotic patients and enhances the vasorelaxation response to NO in cirrhotic rat livers. However, the mechanisms were still unclear. Therefore, our present study aims to evaluate the effects and mechanisms of administration of sildenafil for 1 week on the hepatic microcirculation of cirrhotic rats. Cirrhosis was induced by bile duct ligation with sham-operated rats serving as normal controls. Intrahepatic resistance was evaluated by in situ liver perfusion. Expression of phospho-eNOS (endothelial NO synthase), iNOS (inducible NO synthase), phospho-Akt, PDE-5 (phosphodiesterase-5) and sGC (soluble guanylate cyclase) were determined by Western blot analysis. Biosynthesis of BH4 (tetrahydrobiopterin) and GTPCH-I (GTP cyclohydrolase I) activity were examined by HPLC. Intravital microscopy was used to observe the direct change in hepatic microcirculation. In cirrhotic rat livers, sildenafil treatment increased hepatic sinusoid volumetric flow, NO bioavailability, BH4, GTPCH-I activity, and the protein expression of phospho-Akt, phospho-eNOS and sGC. These events were associated with reduced protein expression of PDE-5, portal perfusion pressure and portal vein pressure. In contrast, sham rats did not produce any significant change in these measurements. In conclusion, sildenafil treatment improves endothelial dysfunction by augmenting NO bioavailability in the hepatic microcirculation.

Serum vascular endothelial growth factor per platelet count in patients with biliary atresia

Background: Biliary atresia (BA) is a progressive, sclerosing, inflammatory process resulting in complete obliteration of the extrahepatic bile ducts. The obstruction of bile flow engenders worsening cholestasis, hepatic fibrosis, and cirrhosis, which lead to portal hypertension and a decline in hepatic synthetic function. Hepatic stellate cells, which play roles in hepatic fibrogenesis, are an important source of various inflammatory mediators including vascular endothelial growth factor (VEGF) in the injured liver. Objectives: Investigate the level of serum VEGF and serum VEGF per platelet count in patients with BA and its relation to clinical characteristics. Methods: Peripheral blood samples were taken from 70 BA patients and 15 healthy control children. Serum VEGF was measured by enzyme-linked immunosorbent assay. We compared serum VEGF and serum VEGF per platelet count in BA patients with the respective results obtained in healthy control children. The relation of serum VEGF per platelet count with clinical variables of BA patients was investigated. Results: Serum VEGF levels and serum VEGF per platelet count in BA patients were not significantly different from those in normal controls (289.64±230.01 pg/mL vs. 312.36±189.05 pg/mL; p=0.72 and 1.72±1.21x106 vs. 1.57±0.97x106; p=0.66). Significant differences were observed among BA patients when VEGF per platelet count was categorized by the presence of esophageal varice (p=0.03). Only in BA patients was the serum level of VEGF correlated with the number of platelets (r=0.53, p<0.001). Conclusion: A high serum VEGF per platelet count is a useful marker for the development of portal hypertension in BA patients, especially for esophageal varice. Serum VEGF per platelet count may be useful for monitoring disease course in BA after hepatic portoenterostomy.

Non-alcoholic steatohepatitis induces non-fibrosis-related portal hypertension associated with splanchnic vasodilation and signs of a hyperdynamic circulation in vitro and in vivo in a rat model

INTRODUCTION

Steatosis, without fibrosis, may lead to changes in liver blood flow, which are poorly understood, and to date have not been correlated to portal pressure and related haemodynamics.

AIMS

To study the temporal relation between progressive steatosis, portal pressure, systemic haemodynamics, vascular responsiveness, mesenteric and portal blood flow in methionine-choline-deficient diet (MCDD)-fed rats.

METHODS

Male Wistar rats fed the MCDD were examined at week (w) 0-1-2-3-4-5-6-7-8, respectively, including systemic haemodynamics and portal pressure. At w0-4-8, in vivo blood flow was measured in the portal vein and the superior mesenteric artery. Dose-response curves to phenylephrine (PE) were established in abdominal aortic rings.

RESULTS

Histology showed 100% steatosis from w3 on. Fibrosis was absent. Significant inflammation was nearly absent upon w4. Portal pressure slightly increased at w2, reached a maximum at w4 [9.4 +/- 0.3 vs 2.9 +/- 0.6 mmHg at w0 (P=0.003)] and remained stable upon w8. Mean arterial blood pressure (MABP) decreased from w2 on [98.7 +/- 5.7 mmHg on w4 compared with 123.8 +/- 1.8 on w0 (P=0.002)]. Portal flow increased from 1.85 +/- 0.11 to 3.07 +/- 0.44 ml/min/100 g on w0 and w8 respectively (P=0.039). Mesenteric artery flow increased from 3.40 +/- 0.26 to 4.56 +/- 0.30 ml/min/100 g on w0 and w8 respectively (P=0.043). Vascular responsiveness to PE gradually decreased from 138 +/- 3% on w0 to 110 +/- 5% on w4 (P=0.013).

CONCLUSION

Steatohepatitis induces significant portal hypertension (PHT) in the absence of fibrosis, associated with an increase in mesenteric arterial and portal venous flow, arterial hyporesponsiveness to vasoconstrictors and a decrease in MABP, indicating the presence of splanchnic vasodilation and hyperdynamic circulation. These alterations resemble those seen in cirrhotic PHT.