Liver Transplantation for Porto-sinusoidal Vascular Liver Disorder: Long-term Outcome

BACKGROUND

Porto-sinusoidal vascular liver disorder (PSVD) is a rare disease that occasionally requires liver transplantation (LT), despite usually presenting preserved liver function. There remains a paucity of data pertaining to LT in PSVD. The aim was to identify features associated with post-LT outcomes in PSVD.

METHODS

Retrospective multicentre study of 79 patients who received LT for PSVD.

RESULTS

Median post-LT follow-up was 37 (range 1-261) mo. Refractory ascites 24 (30%), hepatic encephalopathy 16 (20%), and hepatopulmonary syndrome 13 (16.3%) were the most frequent indications for LT. Hepatocellular carcinoma was the indication in only 2 patients. Twenty-four patients died, 7 due to liver and 17 to non-liver related causes. Post-LT survival was 82.2%, 80.7%, and 68.6% at 1, 2, and 5 y, respectively. Post-LT survival was significantly better in patients without (n = 58) than in those with a persistent severe PSVD-associated condition (n = 21). Pre-LT hyperbilirubinemia levels and creatinine >100 µmol/L were also independently associated with poor survival. Six patients (7.6%) required a second LT. Recurrence of PSVD was confirmed by liver biopsy in only 1 patient and in 3 further patients it was likely.

CONCLUSIONS

LT in PSVD is associated with an acceptable outcome in the absence of associated severe conditions. However, persistence of a severe associated condition, pre-LT high bilirubin levels, or creatinine >100 µmol/L impact outcome, and these are features that should be considered when evaluating PSVD patients for LT. PSVD recurrence is possible after LT and needs to be explored, at least, in cases of posttransplant portal hypertension.

Isoproterenol Disrupts Intestinal Barriers Activating Gut-Liver-Axis: Effects on Intestinal Mucus and Vascular Barrier as Entry Sites

BACKGROUND

The gut-liver-axis presents the pathophysiological hallmark for multiple liver diseases and has been proposed to be modulated during stress and shock. Access to the gut-liver-axis needs crossing of the mucus and gut-vascular barrier. The role of β-adrenoreceptor-activation for both barriers has not been defined and is characterized here.

METHODS

Splanchnic β-adrenergic stimulation was achieved by chronic intraperitoneal application of isoproterenol via alzet-pump in vivo. The intestinal permeability and gut-vascular barrier function was assessed in ileal loop experiments. The extravasation of predefined sizes of fluorescence isothiocyanate (FITC)-dextran molecules in ileal microcirculation was evaluated by intravital confocal laser endomicroscopy in vivo. Mucus parameters thickness, goblet cell count and mucin-expression were assessed by stereomicroscopy, immunostaining and RNA-sequencing respectively. Ileal lamina propria (LP) as well as mesenteric lymph node mononuclear cells was assessed by FACS.

RESULTS

Healthy mice lack translocation of 4 kDa-FITC-dextran from the small intestine to the liver, whereas isoproterenol-treated mice demonstrate pathological translocation (PBT). Mucus layer is reduced in thickness with loss of goblet-cells and mucin-2-staining and -expression in isoproterenol-treated animals under standardized gnotobiotic conditions. Isoproterenol disrupts the gut vascular barrier displaying Ileal extravasation of large-sized 70- and 150 kDa-FITC-dextran. This pathological endothelial permeability and accessibility induced by isoproterenol associates with an augmented expression of plasmalemmal-vesicle-associated-protein-1 in intestinal vessel. Ileal LP after isoproterenol treatment contains more CD11c+-dendritic cells (DC) with increased appearance of CCR7+ DC in mesenteric lymph nodes.

CONCLUSIONS

Isoproterenol impairs the intestinal muco-epithelial and endothelial-vascular barrier promoting PBT to the liver. This barrier dysfunction on multiple levels potentially can contribute to liver injury induced by catecholamines during states of increased β-adrenergic drive.

PREDICT identifies precipitating events associated with the clinical course of acutely decompensated cirrhosis

BACKGROUND & AIMS

Acute decompensation (AD) of cirrhosis may present without acute-on-chronic liver failure (ACLF) (AD-No ACLF), or with ACLF (AD-ACLF), defined by organ failure(s). Herein, we aimed to analyze and characterize the precipitants leading to both of these AD phenotypes.

METHODS

The multicenter, prospective, observational PREDICT study (NCT03056612) included 1,273 non-electively hospitalized patients with AD (No ACLF = 1,071; ACLF = 202). Medical history, clinical data and laboratory data were collected at enrolment and during 90-day follow-up, with particular attention given to the following characteristics of precipitants: induction of organ dysfunction or failure, systemic inflammation, chronology, intensity, and relationship to outcome.

RESULTS

Among various clinical events, 4 distinct events were precipitants consistently related to AD: proven bacterial infections, severe alcoholic hepatitis, gastrointestinal bleeding with shock and toxic encephalopathy. Among patients with precipitants in the AD-No ACLF cohort and the AD-ACLF cohort (38% and 71%, respectively), almost all (96% and 97%, respectively) showed proven bacterial infection and severe alcoholic hepatitis, either alone or in combination with other events. Survival was similar in patients with proven bacterial infections or severe alcoholic hepatitis in both AD phenotypes. The number of precipitants was associated with significantly increased 90-day mortality and was paralleled by increasing levels of surrogates for systemic inflammation. Importantly, adequate first-line antibiotic treatment of proven bacterial infections was associated with a lower ACLF development rate and lower 90-day mortality.

CONCLUSIONS

This study identified precipitants that are significantly associated with a distinct clinical course and prognosis in patients with AD. Specific preventive and therapeutic strategies targeting these events may improve outcomes in patients with decompensated cirrhosis.

LAY SUMMARY

Acute decompensation (AD) of cirrhosis is characterized by a rapid deterioration in patient health. Herein, we aimed to analyze the precipitating events that cause AD in patients with cirrhosis. Proven bacterial infections and severe alcoholic hepatitis, either alone or in combination, accounted for almost all (96-97%) cases of AD and acute-on-chronic liver failure. Whilst the type of precipitant was not associated with mortality, the number of precipitant(s) was. This study identified precipitants that are significantly associated with a distinct clinical course and prognosis of patients with AD. Specific preventive and therapeutic strategies targeting these events may improve patient outcomes.

COVID-19 in an international European liver transplant recipient cohort

OBJECTIVE

Knowledge on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in liver transplant recipients is lacking, particularly in terms of severity of the disease. The aim of this study was to describe the demographic, baseline clinical characteristics and early outcomes of a European cohort of liver transplant recipients with SARS-CoV-2 infection.

DESIGN

We conducted an international prospective study across Europe on liver transplant recipients with SARS-CoV-2 infection confirmed by microbiological assay during the first outbreak of COVID-19 pandemic. Baseline characteristics, clinical presentation, management of immunosuppressive therapy and outcomes were collected.

RESULTS

57 patients were included (70% male, median (IQR) age at diagnosis 65 (57-70) years). 21 (37%), 32 (56%) and 21 (37%) patients had one cardiovascular disease, arterial hypertension and diabetes mellitus, respectively. The most common symptoms were fever (79%), cough (55%), dyspnoea (46%), fatigue or myalgia (56%) and GI symptoms (33%). Immunosuppression was reduced in 22 recipients (37%) and discontinued in 4 (7%). With this regard, no impact on outcome was observed. Forty-one (72%) subjects were hospitalised and 11 (19%) developed acute respiratory distress syndrome. Overall, we estimated a case fatality rate of 12% (95% CI 5% to 24%), which increased to 17% (95% CI 7% to 32%) among hospitalised patients. Five out of the seven patients who died had a history of cancer.

CONCLUSION

In this European multicentre prospective study of liver transplant recipients, COVID-19 was associated with an overall and in-hospital fatality rate of 12% (95% CI 5% to 24%) and 17% (95% CI 7% to 32%), respectively. A history of cancer was more frequent in patients with poorer outcome.

The gut-liver axis in liver disease: Pathophysiological basis for therapy

The gut-liver axis refers to the bidirectional relationship between the gut and its microbiota, and the liver, resulting from the integration of signals generated by dietary, genetic and environmental factors. This reciprocal interaction is established by the portal vein which enables transport of gut-derived products directly to the liver, and the liver feedback route of bile and antibody secretion to the intestine. The intestinal mucosal and vascular barrier is the functional and anatomical structure that serves as a playground for the interactions between the gut and the liver, limiting the systemic dissemination of microbes and toxins while allowing nutrients to access the circulation and to reach the liver. The control of microbial communities is critical to maintaining homeostasis of the gut-liver axis, and as part of this bidirectional communication the liver shapes intestinal microbial communities. Alcohol disrupts the gut-liver axis at multiple interconnected levels, including the gut microbiome, mucus barrier, epithelial barrier and at the level of antimicrobial peptide production, which increases microbial exposure and the proinflammatory environment of the liver. Growing evidence indicates the pathogenetic role of microbe-derived metabolites, such as trimethylamine, secondary bile acids, short-chain fatty acids and ethanol, in the pathogenesis of non-alcoholic fatty liver disease. Cirrhosis by itself is associated with profound alterations in gut microbiota and damage at the different levels of defence of the intestinal barrier, including the epithelial, vascular and immune barriers. The relevance of the severe disturbance of the intestinal barrier in cirrhosis has been linked to translocation of live bacteria, bacterial infections and disease progression. The identification of the elements of the gut-liver axis primarily damaged in each chronic liver disease offers possibilities for intervention. Beyond antibiotics, upcoming therapies centred on the gut include new generations of probiotics, bacterial metabolites (postbiotics), faecal microbial transplantation, and carbon nanoparticles. FXR-agonists target both the gut and the liver and are currently being tested in different liver diseases. Finally, synthetic biotic medicines, phages that target specific bacteria or therapies that create physical barriers between the gut and the liver offer new therapeutic approaches.

FXR modulates the gut-vascular barrier by regulating the entry sites for bacterial translocation in experimental cirrhosis

BACKGROUND & AIMS

Pathological bacterial translocation (PBT) in cirrhosis is the hallmark of spontaneous bacterial infections, increasing mortality several-fold. Increased intestinal permeability is known to contribute to PBT in cirrhosis, although the role of the mucus layer has not been addressed in detail. A clear route of translocation for luminal intestinal bacteria is yet to be defined, but we hypothesize that the recently described gut-vascular barrier (GVB) is impaired in experimental portal hypertension, leading to increased accessibility of the vascular compartment for translocating bacteria.

MATERIALS

Cirrhosis was induced in mouse models using bile-duct ligation (BDL) and CCl₄. Pre-hepatic portal-hypertension was induced by partial portal vein ligation (PPVL). Intestinal permeability was compared in these mice after GFP-Escherichia coli or different sized FITC-dextrans were injected into the intestine.

RESULTS

Healthy and pre-hepatic portal-hypertensive (PPVL) mice lack translocation of FITC-dextran and GFP-E. coli from the small intestine to the liver, whereas BDL and CCl₄-induced cirrhotic mice demonstrate pathological translocation, which is not altered by prior thoracic-duct ligation. The mucus layer is reduced in thickness, with loss of goblet cells and Muc2-staining and expression in cirrhotic but not PPVL mice. These changes are associated with bacterial overgrowth in the inner mucus layer and pathological translocation of GFP-E. coli through the ileal epithelium. GVB is profoundly altered in BDL and CCl₄-mice with Ileal extravasation of large-sized 150 kDa-FITC-dextran, but only slightly altered in PPVL mice. This pathological endothelial permeability and accessibility in cirrhotic mice is associated with augmented expression of PV1 in intestinal vessels. OCA but not fexaramine stabilizes the GVB, whereas both FXR-agonists ameliorate gut to liver translocation of GFP-E. coli.

CONCLUSIONS

Cirrhosis, but not portal hypertension per se, grossly impairs the endothelial and muco-epithelial barriers, promoting PBT to the portal-venous circulation. Both barriers appear to be FXR-modulated, with FXR-agonists reducing PBT via the portal-venous route.

LAY SUMMARY

For intestinal bacteria to enter the systemic circulation, they must cross the mucus and epithelial layer, as well as the gut-vascular barrier. Cirrhosis disrupts all 3 of these barriers, giving bacteria access to the portal-venous circulation and thus, the gut-liver axis. Diminished luminal bile acid availability, cirrhosis and the associated reduction in farnesoid x receptor (FXR) signaling seem, at least partly, to mediate these changes, as FXR-agonists reduce bacterial translocation via the portal-venous route to the liver in cirrhosis.

Addressing Profiles of Systemic Inflammation Across the Different Clinical Phenotypes of Acutely Decompensated Cirrhosis

Background: Patients with acutely decompensated cirrhosis (AD) may or may not develop acute-on-chronic liver failure (ACLF). ACLF is characterized by high-grade systemic inflammation, organ failures (OF) and high short-term mortality. Although patients with AD cirrhosis exhibit distinct clinical phenotypes at baseline, they have low short-term mortality, unless ACLF develops during follow-up. Because little is known about the association of profile of systemic inflammation with clinical phenotypes of patients with AD cirrhosis, we aimed to investigate a battery of markers of systemic inflammation in these patients. Methods: Upon hospital admission baseline plasma levels of 15 markers (cytokines, chemokines, and oxidized albumin) were measured in 40 healthy controls, 39 compensated cirrhosis, 342 AD cirrhosis, and 161 ACLF. According to EASL-CLIF criteria, AD cirrhosis was divided into three distinct clinical phenotypes (AD-1: Creatinine<1.5, no HE, no OF; AD-2: creatinine 1.5-2, and or HE grade I/II, no OF; AD-3: Creatinine<1.5, no HE, non-renal OF). Results: Most markers were slightly abnormal in compensated cirrhosis, but markedly increased in AD. Patients with ACLF exhibited the largest number of abnormal markers, indicating "full-blown" systemic inflammation (all markers). AD-patients exhibited distinct systemic inflammation profiles across three different clinical phenotypes. In each phenotype, activation of systemic inflammation was only partial (30% of the markers). Mortality related to each clinical AD-phenotype was significantly lower than mortality associated with ACLF (p < 0.0001 by gray test). Among AD-patients baseline systemic inflammation (especially IL-8, IL-6, IL-1ra, HNA2 independently associated) was more intense in those who had poor 28-day outcomes (ACLF, death) than those who did not experience these outcomes. Conclusions: Although AD-patients exhibit distinct profiles of systemic inflammation depending on their clinical phenotypes, all these patients have only partial activation of systemic inflammation. However, those with the most extended baseline systemic inflammation had the highest the risk of ACLF development and death.

4-O'-methylhonokiol protects from alcohol/carbon tetrachloride-induced liver injury in mice

Alcoholic liver disease (ALD) is a leading cause of liver cirrhosis, liver cancer, and related mortality. The endocannabinoid system contributes to the development of chronic liver diseases, where cannabinoid receptor 2 (CB2) has been shown to have a protecting role. Thus, here, we investigated how CB2 agonism by 4'-O-methylhonokiol (MHK), a biphenyl from Magnolia grandiflora, affects chronic alcohol-induced liver fibrosis and damage in mice. A combination of alcohol (10% vol/vol) and CCl4 (1 ml/kg) was applied to C57BL/6 mice for 5 weeks. MHK (5 mg/kg) was administered daily, and liver damage assessed by serum AST and ALT levels, histology, gene, and protein expression. Endocannabinoids (ECs) and related lipid derivatives were measured by liquid chromatography and mass spectrometry (LC-MS) in liver tissues. In vitro, MHK was studied in TGFβ1-activated hepatic stellate cells (HSC). MHK treatment alleviated hepatic fibrosis, paralleled by induced expression of matrix metalloproteinases (MMP)-2, -3, -9, and -13, and downregulation of CB1 mRNA. Necrotic lesions and hepatic inflammation were moderately improved, while IL-10 mRNA increased and IFNγ, Mcl-1, JNK1, and RIPK1 normalized by MHK. Hepatic anandamide (AEA) and related N-acetylethanolamines (NAEs) were elevated in MHK group, whereas fatty acid synthase and diacylglycerol O-acyltransferase 2 expression reduced. In vitro, MHK prevented HSC activation and induced apoptosis via induction of bak1 and bcl-2. To conclude, MHK revealed hepatoprotective effects during alcohol-induced liver damage through the induction of MMPs, AEA, and NAEs and prevention of HSC activation, indicating MHK as a potent therapeutic for liver fibrosis and ALD.

KEY MESSAGES

Methylhonokiol improves liver damage and survival. Methylhonokiol reduces hepatic fibrosis and necroinflammation. Methylhonokiol prevents myofibroblast activation and induces apoptosis. Methylhonokiol upregulates endocannabinoids and related N-acylethanolamines. Methylhonokiol contributes to lipid hydrolysis via PPARα/γ.

Polymorphisms in the IL-1 gene cluster influence systemic inflammation in patients at risk for acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) in cirrhosis is an increasingly recognized syndrome characterized by acute decompensation, organ failure(s) and high short-term mortality. Recent findings suggest that an overexuberant systemic inflammation plays a primary role in ACLF progression. In this study, we examined whether genetic factors shape systemic immune responses in patients with decompensated cirrhosis. Six single-nucleotide polymorphisms (SNPs) in inflammation-related genes (interleukin [IL]-1 beta [IL-1β], rs1143623; IL-1 receptor antagonist [IL-1ra], rs4251961; IL-10, rs1800871; suppressor of cytokine signaling-3, rs4969170; nucleotide-binding oligomerization domain-containing protein 2, rs3135500; and chemerin chemokine-like receptor 1, rs1878022) were genotyped in 279 patients with cirrhosis with (n = 178) and without (n = 101) ACLF from the CANONIC study of the CLIF consortium. Among these SNPs, we identified two polymorphisms belonging to the IL-1 gene cluster (IL-1β and IL-1ra) in strong association with ACLF. Both SNPs were protective against ACLF; IL-1β (odds ratio [OR], 0.34, 95% confidence interval [CI], 0.13-0.89; P < 0.05) and IL-1ra (OR, 0.58; 95% CI, 0.35-0.95; P < 0.05) under the recessive and overdominant inheritance models, respectively. These protective SNPs translated into reduced circulating levels of IL-1β, IL-1α, IL-6, granulocyte-colony stimulating factor, granulocyte-macrophage colony-stimulating factor, and C-reactive protein at enrollment as well as after 7-14 days of admission. These findings were confirmed in vitro in leukocytes incubated with plasma from patients with decompensated cirrhosis carrying the protective SNP genotypes. Notably, a higher frequency of the protective genotypes was observed in patients without (80%) than in those with (20%) ACLF. Consistently, patients carrying the combined protective genotypes showed a lower 28-day mortality rate.

CONCLUSION

These data identify two common functional polymorphisms in the IL-1 gene cluster, which are associated with the inflammatory process related to development of ACLF. (Hepatology 2017;65:202-216).

A European survey of perendoscopic treatment of biliary complications in patients with alveolar echinococcosis

BACKGROUND

Biliary complications represent a turning point in the course of Alveolar Echinococcosis (AE). We conducted a European survey to collect data on the current usage and results of perendoscopic interventions (PEIs) for their treatment.

METHODS

Patient's characteristics and follow-up until January 31st, 2015 were recorded using an online questionnaire.

RESULTS

From 18 centers 129 PEIs were analyzed in 38 patients; 139 plastic stents were inserted during 85 PEIs; median time between stent placements was significantly longer when 3 stents or more were placed. Initial symptoms disappeared in 95% and long-term bile duct patency was obtained in 73% of cases. Cholangitis was a more frequent complication of the PEIs (10%) than in other indications; intensive lavage of the bile ducts may prevent this complication.

CONCLUSION

European centers use perendoscopic biliary drainage as an efficient and safe alternative to surgery to treat AE biliary complications. Insertion of multiple plastic stents delays stent occlusion and leads to effective and prolonged bile duct patency.

Clinical Course of acute-on-chronic liver failure syndrome and effects on prognosis

Acute-on-chronic liver failure (ACLF) is characterized by acute decompensation (AD) of cirrhosis, organ failure(s), and high 28-day mortality. We investigated whether assessments of patients at specific time points predicted their need for liver transplantation (LT) or the potential futility of their care. We assessed clinical courses of 388 patients who had ACLF at enrollment, from February through September 2011, or during early (28-day) follow-up of the prospective multicenter European Chronic Liver Failure (CLIF) ACLF in Cirrhosis study. We assessed ACLF grades at different time points to define disease resolution, improvement, worsening, or steady or fluctuating course. ACLF resolved or improved in 49.2%, had a steady or fluctuating course in 30.4%, and worsened in 20.4%. The 28-day transplant-free mortality was low-to-moderate (6%-18%) in patients with nonsevere early course (final no ACLF or ACLF-1) and high-to-very high (42%-92%) in those with severe early course (final ACLF-2 or -3) independently of initial grades. Independent predictors of course severity were CLIF Consortium ACLF score (CLIF-C ACLFs) and presence of liver failure (total bilirubin ≥12 mg/dL) at ACLF diagnosis. Eighty-one percent had their final ACLF grade at 1 week, resulting in accurate prediction of short- (28-day) and mid-term (90-day) mortality by ACLF grade at 3-7 days. Among patients that underwent early LT, 75% survived for at least 1 year. Among patients with ≥4 organ failures, or CLIF-C ACLFs >64 at days 3-7 days, and did not undergo LT, mortality was 100% by 28 days.

CONCLUSIONS

Assessment of ACLF patients at 3-7 days of the syndrome provides a tool to define the emergency of LT and a rational basis for intensive care discontinuation owing to futility.

Elevated levels of endocannabinoids in chronic hepatitis C may modulate cellular immune response and hepatic stellate cell activation

The endocannabinoid (EC) system is implicated in many chronic liver diseases, including hepatitis C viral (HCV) infection. Cannabis consumption is associated with fibrosis progression in patients with chronic hepatitis C (CHC), however, the role of ECs in the development of CHC has never been explored. To study this question, anandamide (AEA) and 2-arachidonoyl glycerol (2-AG) were quantified in samples of HCV patients and healthy controls by gas and liquid chromatography mass spectrometry. Fatty acid amide hydrolase (FAAH) and monoaclyglycerol lipase (MAGL) activity was assessed by [³H]AEA and [³H]2-AG hydrolysis, respectively. Gene expression and cytokine release were assayed by TaqMan PCR and ELISpot, respectively. AEA and 2-AG levels were increased in plasma of HCV patients, but not in liver tissues. Hepatic FAAH and MAGL activity was not changed. In peripheral blood mononuclear cells (PBMC), ECs inhibited IFN-γ, TNF-α, and IL-2 secretion. Inhibition of IL-2 by endogenous AEA was stronger in PBMC from HCV patients. In hepatocytes, 2-AG induced the expression of IL-6, -17A, -32 and COX-2, and enhanced activation of hepatic stellate cells (HSC) co-cultivated with PBMC from subjects with CHC. In conclusion, ECs are increased in plasma of patients with CHC and might reveal immunosuppressive and profibrogenic effects.

The liver may act as a firewall mediating mutualism between the host and its gut commensal microbiota

A prerequisite for establishment of mutualism between the host and the microbial community that inhabits the large intestine is the stringent mucosal compartmentalization of microorganisms. Microbe-loaded dendritic cells trafficking through lymphatics are arrested at the mesenteric lymph nodes, which constitute the firewall of the intestinal lymphatic circulation. We show in different mouse models that the liver, which receives the intestinal venous blood circulation, forms a vascular firewall that captures gut commensal bacteria entering the bloodstream during intestinal pathology. Phagocytic Kupffer cells in the liver of mice clear commensals from the systemic vasculature independently of the spleen through the liver's own arterial supply. Damage to the liver firewall in mice impairs functional clearance of commensals from blood, despite heightened innate immunity, resulting in spontaneous priming of nonmucosal immune responses through increased systemic exposure to gut commensals. Systemic immune responses consistent with increased extraintestinal commensal exposure were found in humans with liver disease (nonalcoholic steatohepatitis). The liver may act as a functional vascular firewall that clears commensals that have penetrated either intestinal or systemic vascular circuits.

Apelin signaling modulates splanchnic angiogenesis and portosystemic collateral vessel formation in rats with portal hypertension

BACKGROUND/AIMS

Angiogenesis is a pathological hallmark of portal hypertension. Although VEGF is considered to be the most important proangiogenic factor in neoangiogenesis, this process requires the coordinated action of a variety of factors. Identification of novel molecules involved in angiogenesis is highly relevant, since they may represent potential new targets to suppress pathological neovascularization in angiogenesis-related diseases like portal hypertension. The apelin/APJ signaling pathway plays a crucial role in angiogenesis. Therefore, we determined whether the apelin system modulates angiogenesis-driven processes in portal hypertension.

METHODS

Partial portal vein-ligated rats were treated with the APJ antagonist F13A for seven days. Splanchnic neovascularization and expression of angiogenesis mediators (Western blotting) was determined. Portosystemic collateral formation (microspheres), and hemodynamic parameters (flowmetry) were also assessed.

RESULTS

Apelin and its receptor APJ were overexpressed in the splanchnic vasculature of portal hypertensive rats. F13A effectively decreased, by 52%, splanchnic neovascularization and expression of proangiogenic factors VEGF, PDGF and angiopoietin-2 in portal hypertensive rats. F13A also reduced, by 35%, the formation of portosystemic collateral vessels.

CONCLUSIONS

This study provides the first experimental evidence showing that the apelin/APJ system contributes to portosystemic collateralization and splanchnic neovascularization in portal hypertensive rats, presenting a potential novel therapeutic target for portal hypertension.

An in vitro model of hepatitis C virus genotype 3a-associated triglycerides accumulation

BACKGROUND/AIMS

The hepatitis C virus (HCV) induces lipid accumulation in vitro and in vivo. Although clinical observations are consistent with a direct effect of HCV genotype 3a on lipid metabolism, experimental systems have focused on the expression of HCV proteins of genotype 1. To extend these observations, we established an in vitro model expressing the HCV core of different genotypes.

METHODS

The HCV core protein from patients with severe (genotype 3a) or no (genotypes 1b, 2a, 3h, 4h and 5a) liver steatosis was expressed in Huh7 cells. Core protein expression (by immunohistochemistry and immunoblot) and triglycerides accumulation (by Oil Red O stain and enzymatic measurement) were evaluated 48h after transfection.

RESULTS

Although triglyceride accumulation occurred with genotypes 1b, 3a and 3h, the genotype 3a core protein expression resulted in the highest level of accumulation (i.e. about 3-fold with respect to 1b, and 2-fold with respect to 3h). This effect was not related to core protein expression levels and was abolished by culturing cells in lipid-free medium.

CONCLUSIONS

Consistent with observations in chronic hepatitis C patients, the in vitro expression of HCV genotype 3a core protein is the ideal candidate model for studying the mechanisms of HCV-associated steatosis.