Characterization of the cross-neutralizing antibody response against hepatitis C virus in the liver transplantation setting.

Neutralizing antibody (nAb) activity during the course of natural infection is believed to be crucial to combating virus propagation. The aim of this study was to measure the impact of nAb response on HCV early kinetics and genetic evolution in the liver transplantation (LT) setting. A cohort of 28 patients undergoing LT for HCV-related cirrhosis was included in the study. Viral load, nAb titers and hypervariable region 1 (HVR1) sequences were determined in serum samples obtained before and at different time points after LT. Serum nAb titers were assessed using HCV pseudoparticles (HCVpp). HVR1 sequences were obtained by direct sequencing. Patients were classified according to viral kinetic patterns (plateau or increasing), during the first week after LT. All patients demonstrated high titers of nAbs before LT, although this was not associated with early kinetic patterns or HVR1 evolution during the first week after LT. We found that in patients with plateau HCV early kinetics, the virus required adaptive mutations, while in those with increasing viral loads, the HVR1 region remained largely conserved (p = 0.015). These data suggest that HCV adaptation via selection of the best-fitted variants may account for early viral kinetics following LT.

Donor and recipient IL28B polymorphisms in HCV-infected patients undergoing antiviral therapy before and after liver transplantation.

IL28B gene polymorphisms are associated with the response to antiviral therapy in hepatitis C patients. We investigated the influence of IL28B polymorphisms on the response to therapy before and after liver transplantation (LT). Genotyping of SNPs rs8099917 and rs12979860 was performed in 128 HCV-infected liver transplant recipients and in their donors; all patients underwent antiviral treatment after LT. The prevalence of genotypes rs12979860CC and rs8099917TT was higher in donors than in recipients (50% vs.19%, p < 0.001 and 67% vs. 38%, p < 0.001, respectively). Response to antiviral therapy was significantly higher for recipient genotype rs12979860CC as compared to rs12979860CT/TT both before (100% vs. 48% p = 0.013) and after LT (59% vs. 25% p = 0.002). The figures were almost identical for SNP rs8099917. Sustained virological response after LT was particularly high in patients with favorable recipient and donor genotypes (p < 0.01 for both SNPs). In a subgroup of 34 patients treated while awaiting LT, a favorable donor IL28B genotype was associated with an improved virological response after LT. Our results support a major role of recipient IL28B genotype in the response to antiviral treatment for hepatitis C recurrence. Interestingly, donor genotype also seems to influence the response pattern, especially in recipients who have a favorable IL28B genotype.

Hepatitis C virus compartmentalization and infection recurrence after liver transplantation.

Hepatitis C virus (HCV) compartmentalization may have important implications in the pathogenesis of HCV infection. The aim of this study was to investigate the presence and relevance of HCV compartmentalization in the setting of liver transplantation (LT). We collected samples of serum, peripheral blood mononuclear cells (PBMC), perihepatic lymph nodes (PLN) and liver explant at the time of LT, and serum and PBMC after transplantation from 57 HCV-infected cirrhotic patients undergoing LT: 38 individuals received antiviral treatment before LT and 19 were untreated controls. HCV-RNA levels were determined by real-time PCR and the hypervariable region 1 (HVR-1) was sequenced. HCV-RNA was detected in all samples from control patients. In virological responders, recurrence after LT was associated with residual HCV-RNA in the liver explant. Within the entire cohort, 47% of patients harbored differences in direct sequences from distinct compartments. Quasispecies analysis revealed that in most cases, HVR-1 sequences recovered after infection recurrence were identical or closely related to those isolated from the liver explant and serum at the time of LT. Our study shows that a significant proportion of HCV-infected cirrhotic patients exhibit compartmentalization. Viral variants originating within the liver appear to be the main cause of HCV recurrence after LT.

Anti-viral therapy can be delayed or avoided in a significant proportion of HBeAg-negative Caucasian patients in the Grey Zone.

BACKGROUND: Grey Zone (GZ) is an ill-defined situation including patients falling between inactive carrier (IC) state and HBeAg-negative chronic hepatitis B (HBeAg-negative CHB). AIMS: To assess the long-term outcomes of GZ patients compared to IC in the absence of treatment. METHODS: Retrospective analysis of 287 IC and GZ HBeAg-negative patients. Patients were classified into 4 groups at baseline: HBV-DNA <2000 IU/mL and ALT <40 U/L (IC), HBV-DNA <2000 IU/mL and ALT 40-80 U/L (GZ-1), HBV-DNA 2000-20 000 IU/mL and ALT <40 U/L (GZ-2) or ALT 40-80 U/L (GZ-3). Data were also analysed using AASLD ALT criteria. RESULTS: After a median follow-up of 8.2 (5-19) years, HBsAg loss occurred in about 15% ICs or GZ patients. Transition into IC state occurred in 40% of GZ patients. DNA fluctuations >2000 IU/mL correlated inversely with transition into IC and HBsAg loss. HBsAg levels were significantly lower in ICs than in GZ patients (338 IU/mL [20-3269] vs 5763 IU/mL [2172-17 754]; P < 0.05). Among the latter group, there was an increasing gradient of HBsAg levels from GZ-1 to GZ-3 patients (P < 0.05). HBeAg-negative CHB occurred in only 18 (6.3%) GZ patients. No patient developed cirrhosis nor advanced fibrosis. ALT/HBV-DNA fluctuations and HBeAg-negative CHB development were more frequent in genotype B/C patients, whereas HBsAg loss occurred only in genotype A/D patients. CONCLUSIONS: Most Caucasian GZ patients present excellent long-term outcomes in the absence of treatment, with a high rate of HBsAg loss and low rate of progression to HBeAg-negative CHB. HBV-genotyping and HBsAg levels could help to predict outcomes and better classify GZ patients.

Hepatitis B reactivation in patients with chronic hepatitis C undergoing anti-viral therapy with an interferon-free regimen.

BACKGROUND: A few cases of hepatitis B virus (HBV) reactivation during anti-viral therapy against hepatitis C (HCV) have been reported. However, the information regarding the real impact of this phenomenon is scarce. AIM: To evaluate the risk of HBV reactivation during anti-viral therapy against HCV with an interferon-free regimen with direct-acting anti-virals (DAAs). METHODS: Observational and prospective study of 352 patients receiving DAAs therapy between September 2015 and May 2016. HBV-DNA and ALT levels were monitored at baseline, at week 4 of anti-viral therapy, at end of treatment and 12 weeks after treatment discontinuation in patients with HBV surface antigen (HBsAg) positive or HBV core antibody (anti-HBc) positive before starting anti-viral therapy. RESULTS: Ten (2.8%) and 64 (18%) patients were HBsAg and anti-HBc positive at baseline, respectively. Five (50%) of 10 HBsAg positive and one (1.6%) of 64 anti-HBc positive patients presented HBV virological reactivation (>1log increase in HBV-DNA levels). None of these patients presented clinical reactivation (increase in ALT levels). CONCLUSIONS: HBV virological reactivation is frequent in HBsAg+ patients receiving anti-viral therapy against HCV. However, HBV-DNA elevations were modest (<20 000 IU/mL) and without clinical impact (no ALT elevation).

In vivo and in vitro pharmacological characterization of SVT-40776, a novel M3 muscarinic receptor antagonist, for the treatment of overactive bladder.

BACKGROUND AND PURPOSE: Highly selective M(3) muscarinic receptor antagonists may represent a better treatment for overactive bladder syndrome, diminishing side effects. Cardiac side effects of non-selective antimuscarinics have been associated with activity at M(2) receptors as these receptors are mainly responsible for muscarinic receptor-dependent bradycardia. We have investigated a novel antimuscarinic, SVT-40776, highly selective for M(3) over M(2) receptors (Ki = 0.19 nmol.L(-1) for M(3) receptor affinity). This study reports the functional activity of SVT-40776 in the bladder, relative to its activity in atria. EXPERIMENTAL APPROACH: In vitro and ex vivo (oral dosing) inhibition of mouse detrusor and atrial contractile responses to carbachol were used to study the functional activity of SVT-40776. The in vivo efficacy of SVT-40776 was characterized by suppression of isovolumetric spontaneous bladder contractions in anaesthetized guinea pigs after intravenous administration. KEY RESULTS: SVT-40776 was the most potent in inhibiting carbachol-induced bladder contractions of the anti-cholinergic agents tested, without affecting atrial contractions over the same range of concentrations. SVT-40776 exhibited the highest urinary versus cardiac selectivity (199-fold). In the guinea pig in vivo model, SVT-40776 inhibited 25% of spontaneous bladder contractions at a very low dose (6.97 microg.kg(-1) i.v), without affecting arterial blood pressure. CONCLUSIONS AND IMPLICATIONS: SVT-40776 is a potent inhibitor of M(3) receptor-related detrusor contractile activity. The absence of effects on isolated atria preparations represents an interesting characteristic and suggests that SVT-40776 may lack unwanted cardiac effects; a feature especially relevant in a compound intended to treat mainly elderly patients.

Possible alternative to European Pharmacopoeia's method of analysis Test for Fc Function of Immunoglobulin (2.7.9) by using tetanus toxoid as antigen.

Preparations of intravenous immunoglobulins must keep functional integrity throughout the purification process. In order to assess Fc fragment functionality, the European Pharmacopoeia proposes the Test for Fc function of immunoglobulin (2.7.9), which is based on a rubella antigen of high titre. Sometimes, such antigen is difficult to obtain. In the present study, we develop the same assay using tetanus toxoid instead of rubella antigen, adapting the procedure for the use of tetanus toxoid. The comparison between rubella-based and tetanus-based assays showed that the slopes of the haemolysis curves were higher if red blood cells had been sensitised with the rubella antigen than with tetanus toxoid. Nonetheless, the tetanus-based assay gave satisfactory results and it could be a good alternative antigen target.

Protection from inflammatory disease in insulin resistance: the role of mannan-binding lectin.

AIMS/HYPOTHESIS: Decreased sensing of the innate immune system may lead to chronic activation of the inflammatory cascade. We hypothesised that mannan-binding lectin (MBL) deficiency may confer risk of obesity and insulin resistance. MATERIALS AND METHODS: We performed a cross-sectional study of MBL protein concentration (n=434) and MBL2 gene mutations (exon 1) (n=759) in association with obesity, markers of inflammation and insulin action (euglycaemic clamp, n=113), and a longitudinal study of MBL protein before and after weight loss in obese patients (n=10). We also studied the effects of MBL in vitro in muscle cells and circulating MBL-A (mouse equivalent of human MBL) in a mouse model. RESULTS: Among 434 consecutive non-diabetic men, the age-adjusted serum MBL concentration was lower in obese subjects than in lean subjects (median: 959 microg/ml [interquartile range: 116.8-2,044 microg/ml] vs 1,365 [467-2,513] microg/ml; p=0.01) and was accompanied by increased serum inflammatory markers. Insulin action correlated significantly with serum MBL (r=0.49, p<0.0001). Serum MBL concentration increased by a median of 110.2% after weight loss. The change in serum concentration of MBL was positively associated with the increase in insulin sensitivity (r=0.713, p=0.021). At least one MBL2 gene mutation was present in 48.2% of obese vs 39.3% of non-obese subjects (p=0.037). The plasma concentration of MBL-A was lower in insulin-resistant obese ob/ob mice, as was the glucose/insulin ratio. Incubation of rat soleus muscle with human MBL markedly increased fatty acid oxidation. CONCLUSIONS/INTERPRETATION: These findings suggest that MBL, previously thought only to be involved in inflammation and immune system function, affects metabolic pathways.

Production and characterization of monoclonal antibodies against conserved epitopes of P-selectin (CD62P).

P-selectin (CD62P) is an adhesion molecule expressed on the activated endothelium and activated platelets that is involved in the initial attachment of leukocytes to inflamed vascular endothelium. Blocking monoclonal antibodies (mAbs) and P-selectin-deficient mice have shown that P-selectin is a potential target in anti-inflammatory therapy. Most mAbs against P-selectin do not bind to conserved epitopes, including the ligand-binding region, since P-selectin from mammalian species shares high amino acid sequence homology. The aim of this study was to generate a novel panel of anti-P-selectin mAbs against the conserved epitopes present in several animal species. To produce these mAbs, P-selectin-deficient mice were immunized with a pre-B-cell line transfected with human P-selectin cDNA. Twelve mouse mAbs that recognize human P-selectin were obtained. Individual mAbs that bound to human, rat, mouse, rabbit and pig activated platelets were characterized by flow-cytometry, immunohistochemistry, adhesion assays and immunoprecipitation. Four of these mAbs (P-sel.KO.2.3, P-sel.KO.2.4, P-sel.KO.2.7 and P-sel.KO.2.12) cross-reacted with human, rat and mouse P-selectin. Another three mAbs (P-sel.KO.2.2, P-sel.KO.2.11 and P-sel.KO.2.12) blocked the attachment of HL60 cells to P-selectin-transfected COS cells, demonstrating that these mAbs inhibit P-selectin-mediated adhesion. MAb cross-blocking experiments showed that these three mAbs bind to very close and overlapping epitopes. An ELISA assay using mAbs P-sel.KO.2.3 and P-sel.KO.2.12 was designed to measure soluble rat, mouse and human P-selectin. These anti-P-selectin mAbs are unique since they recognize common epitopes conserved during mammalian evolution and they may be useful for studying P-selectin function in inflammatory models in various species.

Neutrophil adhesion is impaired in the mesentery but not in the liver sinusoids of portal hypertensive rats.

Altered leukocyte/cytokine response to inflammation has been observed in human and experimental portal hypertension. The aim of this study was to characterize leukocyte adhesion in portal hypertensive (PPVL) rats stimulated with endotoxin. Leukocyte rolling, adhesion, and migration assessed by intravital microscopy were impaired in mesenteric venules after lipopolysaccharide administration (150 microg/kg) in PPVL vs. sham-operated rats. Analysis of leukocyte L-selectin expression and soluble L-selectin showed that this defective adhesion was related to increased L-selectin shedding. In vitro experiments using isolated leukocytes treated with phorbol 12-myristate 13-acetate showed that monocytes and neutrophils but not lymphocytes were hyperreactive to cell activation, as measured by CD11b overexpression and increased L-selectin shedding in PPVL rats. However, neutrophil emigration in liver sinusoids and in the lung 3 h after endotoxin injection were similar in both groups of animals. Thus the alterations in leukocyte activation and adhesion molecule expression observed in this study may contribute to a better understanding of the higher susceptibility and severity of bacterial infections in cirrhotic patients with portal hypertension.

The role of portal pressure in the severity of bleeding in portal hypertensive rats.

The aim of this study was to investigate the role of portal hypertension determining the severity of bleeding in portal hypertensive rats. The effects of section of branches of the ileocolic vein were studied in sham-operated (SO), partial portal vein-ligated (PPVL), and common bile duct-ligated (CBDL) rats. The ensuing hemorrhage was compared with that caused by section of femoral vein, where the portal hypertensive factor is excluded. In PPVL rats, section of branches of increasing size (divided into fourth, third, second, and first order) resulted in increasingly severe bleeding (arterial pressure: / +/- 4%, / 6 +/- 12%, / /15 +/- 8%, and / 28 +/- 13%; P <.005; hematocrit / 4 +/- 2%, / 6 +/- 1%, / 7 +/- 2%, and / 10 +/- 4%; P <.005). Bleeding from first-order branches was mild in SO, moderate in PPVL, and severe in CBDL rats, as shown by increasing changes in arterial pressure (/ 3 +/- 3%, / 12 +/- 16% and, / 43 +/- 23%; P <.01), hematocrit (/ 4 +/- 1%, / 12 +/- 2%, and / 32 +/- 19%; P <.01), and mortality (0%, 0%, and 56%; P <.001). Greater blood loss in CBDL rats was associated with higher portal pressure (16.6 +/- 2.7 vs. 13. 1 +/- 1.1 mm Hg in PPVL; P <.01) and more prolonged bleeding time (70 +/- 4 vs. 35 +/- 3 seconds in PPVL; P <.001). Vessels were similarly dilated in CBDL and PPVL (0.7 +/- 0.2 and 0.7 +/- 0.1 vs. 0.4 +/- 0.1 mm in SO; P <.05). Section of femoral vein caused equal blood loss in SO, PPVL, and CBDL rats, assessed by falls in hematocrit (/ 8 +/- 2%, / 7 +/- 1%, / 8 +/- 1%, respectively; NS) and by the blood loss (3.6 +/- 0.7, 3.5 +/- 0.9, and 3.8 +/- 0.7 g; NS). The study shows that the degree of portal pressure elevation is a major determinant of the severity of portal hypertension-related bleeding in PPVL and CBDL rats.

Impaired mesenteric leukocyte recruitment in experimental portal hypertension in the rat.

Increased incidence of septic complications in human and experimental portal hypertension has been documented. Because development of an inflammatory response is essential in defense against infectious agents, the aim of this study was to assess leukocyte-endothelial cell interactions in an experimental model of portal hypertension. Intravital microscopy studies showed that under baseline conditions, leukocyte rolling, adhesion, and emigration in mesenteric venules were similar in control, sham operated (SO), and partial portal vein ligated (PPVL) rats. Compared with either control or SO rats, PPVL animals exhibited a markedly reduced recruitment of rolling, adherent, and emigrated leukocytes in response to leukotriene B(4) (LTB(4)) stimulation. Similarly, platelet-activating factor (PAF) superfusion, which induced a large increment in leukocyte rolling and adherence in control and SO rats, was without any effect in PPVL animals. Endothelial P-selectin expression in control rats, as measured by the double radio-labeled monoclonal antibody (mAb) technique, was not modified by LTB(4), but significantly increased in response to PAF. PPVL rats had a significantly lower expression of P-selectin after stimulation with PAF. Neutrophils isolated from PPVL rats exhibited increased L-selectin shedding and CD11b up-regulation in response to PAF and LTB(4), compared with neutrophils isolated from SO rats. These observations indicate that portal hypertension is associated with a defective inflammatory response, which is manifested as a decreased recruitment of rolling leukocytes, and subsequently reduced adhesion/emigration. This defect appears to result from a reduced endothelial P-selectin up-regulation and increased L-selectin shedding.

Role of P-selectin in radiation-induced intestinal inflammatory damage.

The aims of our study were to characterize the dose- and time-dependent changes in endothelial P-selectin expression and the role of this adhesion molecule as a mediator of radiation-induced inflammation. For that purpose, endothelial P-selectin expression was measured by the radiolabeled antibody technique in control and irradiated mice at 2, 6, and 24 hr following abdominal irradiation with 4 or 10 Gy; leukocyte endothelial cell interactions were assessed using intravital microscopy in intestinal venules following irradiation at the aforementioned doses and times in C57BL/6 and P-selectin-deficient mice. In wild-type mice, radiation induced a time- and dose-dependent up-regulation of P-selectin and a significant increase in the flux of rolling leukocytes 2 hr after irradiation. Irradiation induced a significant increase in leukocyte adhesion that was dose-dependent. Following irradiation, P-selectin-deficient mice did not show any increase in leukocyte rolling but did demonstrate a response in leukocyte adhesion similar to that of the wild-type mice. Radiation-induced dose-dependent histological inflammatory damage that did not differ between P-selectin-deficient and wild-type mice. We conclude that P-selectin is up-regulated following irradiation and is a key molecular determinant of leukocyte rolling but not leukocyte adhesion in this inflammatory condition. Therefore, isolated neutralization of this adhesion molecule is not an effective means for preventing radiation-induced inflammation.

Effects of blood volume restitution following a portal hypertensive-related bleeding in anesthetized cirrhotic rats.

The aim of this study was to investigate the influence of different strategies of blood volume restitution in the outcome of portal hypertension-related bleeding in anesthetized cirrhotic rats. Gastrointestinal hemorrhage was induced by sectioning a first order branch of the ileocolic vein in 38 cirrhotic rats (common bile duct ligation and occlusion). The subsequent hypovolemic shock was treated with no transfusion (n = 17), moderate transfusion (50% of expected blood loss, 5 mL, n = 11), and total transfusion (100% of expected blood loss, 10 mL, n = 10). At the end of the blood transfusion period (minute 15), mean arterial pressure (MAP) partially recovered in rats receiving moderate transfusion or no transfusion but decreased in the 10-mL transfusion group ( downward arrow 12 +/- 43%, P < .05 vs. no transfusion and 5 mL transfusion). After transfusion, groups given no or 5 mL transfusion remained hemodynamically stable. However, rats receiving 10 mL transfusion continued to deteriorate with persistent bleeding and progressive fall in MAP ( downward arrow 65 +/- 12%; P < .05 vs. no transfusion and 5 mL transfusion). Collected blood loss was significantly greater in the 10-mL group (20.0 +/- 1.5 g) than in groups given 5 mL (15.9 +/- 2.8 g; P < .05) or no transfusion (13.2 +/- 2.1 g; P < .05 vs. 10 mL and 5 mL transfusion). Survival in the no transfusion group was 47%. Rats given 5-mL transfusion had 64% survival. The worst survival was observed in the 10-mL transfusion group (0% survival; P < .05). We concluded that a transfusion policy aimed at completely replacing blood loss worsens the magnitude of bleeding and mortality from portal hypertensive-related bleeding in cirrhotic rats. On the contrary, moderate blood transfusion allowed hemodynamic stabilization and increased survival.

Enhanced monocyte activation and hepatotoxicity in response to endotoxin in portal hypertension.

BACKGROUND/AIMS: Septic shock is a systemic response to infection, and it causes a high mortality rate in cirrhotic patients. The mechanisms responsible for this susceptibility in cirrhosis are poorly understood. The aim of this study was to investigate whether monocyte activation and hepatic function are altered in portal hypertension after endotoxin administration. METHODS: Portal-hypertensive and sham-operated rats were used. Plasma levels of tumor necrosis factor-alpha after lipopolysaccharide stimulation (both in vivo and in vitro) were measured by ELISA. CD11b/CD18 integrin expression on leukocyte membrane was measured by flow cytometry. Plasma transaminase activities were also determined. RESULTS: The levels of tumor necrosis factor-alpha in plasma and the expression of CD11b/CD18 on leukocytes in portal-hypertensive rats was similar to that in sham-operated rats. Injection of 150 microg/kg of lipopolysaccharide produced a 9-fold increase in plasma levels of tumor necrosis factor-alpha in portal-hypertensive compared with sham-operated rats, together with a significant up-regulation of CD11b/CD18 expression on monocytes and an elevation in plasma transaminase activity. Blood leukocytes incubated in vitro with lipopolysaccharide (0.5 microg/ml) induced a hypersecretion of tumor necrosis factor-alpha in portal-hypertensive rats, as compared to sham-operated rats. CONCLUSIONS: This study shows that monocytes from portal-hypertensive rats have an enhanced response to endotoxin, leading to hepatotoxicity.