Marta Casado

Urgent Transjugular Intrahepatic Portosystemic Shunt for Control of Acute Variceal Bleeding

Objective:Endoscopic sclerotherapy and pharmacological therapy are widely used in the treatment of acute variceal hemorrhage. However, they fail at arresting acute bleeding in 20–30% of bleeding episodes. The efficacy of transjugular intrahepatic portosystemic shunt (TIPS) in the prevention of recurrent variceal bleeding has been proved recently, but the effectiveness and safety of urgent TIPS in the treatment of acute variceal bleeding refractory to conventional therapy are still under evaluation.Methods:Over 4.5 yr, 358 variceal hemorrhage episodes were treated in our hospital. Pharmacological and endoscopic therapy failed to control hemorrhage in 93 episodes. Thirty-two patients died because of uncontrolled massive bleeding. In 56 patients, TIPS (Strecker stent) was performed after temporary control of the episode with balloon tamponade.Results:Eleven of 56 patients with urgent TIPS belonged to Child-Pugh class A, 22 to class B, and 23 to class C. The mean time between indication and insertion was 17 ± 10 h (range 4–24 h). Control of bleeding was achieved in 53 patients (95%). Eight patients had recurrent bleeding at 1 month after TIPS, seven of them during the first week after the procedure. The 1-month actuarial probability of rebleeding was 22%. The main complications of the procedure were massive hemoperitoneum (n = 1), cardiorespiratory arrest (n = 2), cardiac failure (n = 1), acute renal failure-(n = 2), and bacteremia (n = 7). Operative mortality (30 days) was 28%. The actuarial probability of survival at 30 days was significantly lower in Child-Pugh class C than in class A or B (48%vs 90%; p < 0.001). The presence of ascites, hepatic encephalopathy, and serum albumin level before TIPS were independent prognostic factors associated with the risk of operative mortality.Conclusions:Urgent TIPS is an effective alternative for the treatment of acute variceal bleeding refractory to endoscopic and pharmacological therapy, but sometimes is associated with major complications. Because of the high operative mortality rate in patients with severe liver failure, careful selection of patients is required before TIPS.

Contribution of cyclooxygenase 2 to liver regeneration after partial hepatectomy

Partial hepatectomy (PH) triggers a rapid regenerative response in the remaining tissue to reinstate the organ function and the cell numbers. Among the molecules that change in the course of regeneration is an accumulation of prostaglandin E2 in the sera of rats with PH. Analysis of the cyclooxygenase (COX) isoenzymes in the remnant liver showed the preferential expression of COX‐2 in hepatocytes. Cultured regenerating hepatocytes expressed significant levels of COX‐2, a process that was not observed in the sham counterparts. Maximal expression of COX‐2 was detected 16 h after PH with increased levels present even at 96 h. Pharmacological inhibition of COX‐2 activity with NS398 shunted the up‐regulation of cell proliferation after PH, which suggests a positive interaction of prostaglandins with the progression of the cell cycle. Similar results were obtained after PH of mice lacking the COX‐2 gene. The expression of COX‐2 in regenerating liver was concomitant with a decrease in CCAAT‐enhancer binding protein (C/EBP‐α) level and an increase in the expression of C/EBP‐β and C/EBP‐δ. These results suggest a contribution of the enhanced synthesis of prostaglandins to liver regeneration observed after PH.

Physiological responses to mercury in feral carp populations inhabiting the low Ebro River (NE Spain), a historically contaminated site

The low Ebro River course (Northeast Spain) is historically affected by mercury pollution due to a chlor-alkali plant operating at the town of Flix for more than a century. River sediments analysed during the last 10 years showed high mercury levels in the river section starting just downstream the factory and spanning some 90km, down to the river delta. The possible environmental impact was studied by a combination of field and laboratory studies. Mercury concentrations in liver, kidney and muscle of feral carp (Cyprinus carpio) sampled downstream Flix were one to two orders of magnitude higher than those from carps sampled upstream Flix. Elevated levels of mercury in these samples associated with significant increases on the concentration of reduced glutathione (GSH) in liver and on mRNA expression of two metallothionein genes, MT1 and MT2, in kidney and, partially, in scales, but not in liver. Conversely, no biochemical evidence for oxidative stress or DNA damage was found in these tissues. Non-contaminated carps subjected to intraperitoneal mercury injection resulted in a 20-fold increase of MT1 and MT2 mRNA levels in carp kidney, with minimal changes in liver levels. Our data suggests the coordinate increase of metallothionein mRNA in kidney and of GSH in liver constitutes an excellent marker of exposure to sub-toxic mercury levels in carps. This study also demonstrates that apparently healthy fish populations may exceed the mercury contamination acceptable for human consumption.

Human SREBP1c Expression in Liver Is Directly Regulated by Peroxisome Proliferator-activated Receptor α (PPARα)

Sterol regulatory element binding proteins (SREBPs) regulate the expression of a number of enzymes, which catalyze the synthesis of fatty acids, cholesterol, triglycerides, and phospholipids. SREBP1c is the most relevant isoform in the adult liver, and its expression is controlled by the nutritional state. Transcriptional regulation studies into the SREBP1c gene, performed in the last few years, have improved our knowledge of the variability of signals that converge on its promoter region. Insulin, cholesterol derivatives, T3 and other endogenous molecules have been demonstrated to regulate the SREBP1c expression, particularly in rodents. The present study aimed to perform a detailed analysis of the human SREBP1c gene promoter structure in liver cells by focusing on responses to diverse metabolic signals. Serial deletion and mutation assays reveal that both SREBP (SRE) and LXR (LXRE) response elements are involved in SREBP1c transcription regulation mediated by insulin and cholesterol derivatives. We discovered that peroxisome proliferation-activated receptor alpha (PPARα) agonists enhance the activity of the SREBP1c promoter; a DR1 element, at −453 in the human promoter was involved in this activation. Moreover, PPARα agonists act in cooperation with LXR or insulin to induce lipogenesis. Collectively, our results identify PPARα as a novel regulatory factor in SREBP1c regulation which plays a relevant role in the interplay between lipids and insulin metabolic regulation.

Attenuation of emerging organic contaminants in a hybrid constructed wetland system under different hydraulic loading rates and their associated toxicological effects in wastewater

The capacity of a hybrid constructed wetland (CW) system consisting of two vertical flow (VF) CWs working alternatively (3m(2)), one horizontal flow (HF) CW (2m(2)) and one surface flow (FWS) CW (2m(2)) in series to eliminate 13 emerging organic contaminants (EOCs) under three different hydraulic loading rates (HLRs) (0.06, 0.13 and 0.18 m d(-1) considering the area of the two VF beds) was studied through a continuous injection experiment. General toxicity, dioxin-like activity, antimicrobial activity and estrogenicity were also measured under the highest hydraulic loading rate. The hybrid system was highly efficient on the removal of total injected EOCs (except for antibiotics, 43 ± 32%) at all three HLRs (87 ± 10%). The removal efficiency in the hybrid CW system showed to decrease as the HLR increased for most compounds. The VF wetlands removed most of the injected EOCs more efficiently than the other two CWs, which was attributable to the predominant aerobic degradation pathways of the VF beds (70 ± 21%). General toxicity was reduced up to 90% by the VF beds. Estrogenicity and dioxin-like activity were similarly reduced by the VF and the HF wetlands, whereas antimicrobial activity was mainly removed by the FWS wetland. Bearing this in mind, this injection study has demonstrated that the use of hybrid CW systems is a suitable wastewater technology for removing EOCs and toxicity even at high HLRs.

Expression of cyclooxygenase‐2 in foetal rat hepatocytes stimulated with lipopolysaccharide and pro‐inflammatory cytokines

1 Cyclooxygenase‐2 (COX‐2) is involved in the biosynthesis of prostanoids in the course of inflammatory reactions. This isoenzyme is regulated at the transcription level and many cells express COX‐2 upon challenge with lipopolysaccharide (LPS) or pro‐inflammatory cytokines. 2 Since hepatocytes respond to LPS and pro‐inflammatory stimuli, we investigated the expression of COX‐2 in foetal and adult hepatocytes upon challenge with these substances. 3 COX‐2 was expressed in foetal hepatocytes incubated with LPS, tumour necrosis factor‐α and interleukin‐1β. This response rapidly decreased after birth and was absent in hepatocytes from animals aged 2 days or more and treated under identical conditions. The expression of COX‐2 was determined at the mRNA, protein and enzyme activity levels using Northern and Western blot, and following the synthesis of prostaglandin E2, respectively. The use of NS 398, a specific pharmacological inhibitor of COX‐2, confirmed the expression of this isoenzyme in activated foetal hepatocytes. 4 Synergism in COX‐2 expression was observed between LPS, tumour necrosis factor‐α and interleukin‐1β. Interleukin‐6 and permeant analogues of cyclic AMP failed to induce COX‐2 or to synergize with LPS. Also, transforming growth factor‐β inhibited the LPS‐ and pro‐inflammatory cytokines‐dependent expression of COX‐2. 5 These results indicate that foetal hepatocytes are competent to express COX‐2 upon challenge with pro‐inflammatory stimuli, a process lost completely in hepatocytes isolated from animals aged 2 days.

Effects of transjugular intrahepatic portasystemic shunt (TIPS) on splanchnic and systemic hemodynamics, and hepatic function in patients with portal hypertension. Preliminary results.

The purpose of this study was to evaluate the short-term splanchnic and systemic hemodynamics and hepatic function after TIPS creation. Fifteen cirrhotics with portal hypertension underwent TIPS placement for treatment of variceal hemorrhage, and extensive hemodynamic studies including right heart catheterization, portal pressure measurement, hepatic blood flow, and indocyanine green (ICG) clearance were performed before and 1 month after the procedure. Self-expandable metal stents (Strecker 11 mm diameter) were placed in all cases. Portasystemic gradient significantly diminished (18.3±4.2 vs 8±2.8; 54%±18 mm Hg) after the technique, mainly due to a decrease in portal pressure, and remained stable in the final study. Cardiac output and mean arterial pressure increased (6.2±1.4 vs 8.2±1.8 liters/min, 80.1±10.1 vs 91±11.2 mm Hg, respectively), and a decrease in systemic vascular resistance was registered (1018±211 vs 872±168 dyne/sec/cm5); the hepatic blood flow and ICG clearance also decreased significantly (1.5±0.7 vs 0.68±0.2 liters/min, 0.4±0.2 vs 0.24 ±0.06 liters/min, respectively). There was an increase in the preload at the final study, as evidenced by a marked increase in right atrial (3.1±1.6 vs 4.35±2.2 mm Hg, +15%,P<0.05), pulmonary arterial (12.2±2.4 vs 15.9±3.2 mm hg, +31.8%,P<0.001), and wedge pulmonary arterial pressures (6.9±2.4 vs 9.8±3.1 mm Hg, +53%,P<0.001). These results suggest that TIPS worsens the hyperdynamic syndrome associated to portal hypertension. Therefore, in patients with cardiac insufficiency, this procedure should be evaluated. TIPS also decreases the hepatic blood flow, inducing a mild worsening in liver function.

Cooperation of Adenosine with Macrophage Toll-4 Receptor Agonists Leads to Increased Glycolytic Flux through the Enhanced Expression of PFKFB3 Gene

Macrophages activated through Toll receptor triggering increase the expression of the A2A and A2B adenosine receptors. In this study, we show that adenosine receptor activation enhances LPS-induced pfkfb3 expression, resulting in an increase of the key glycolytic allosteric regulator fructose 2,6-bisphosphate and the glycolytic flux. Using shRNA and differential expression of A2A and A2B receptors, we demonstrate that the A2A receptor mediates, in part, the induction of pfkfb3 by LPS, whereas the A2B receptor, with lower adenosine affinity, cooperates when high adenosine levels are present. pfkfb3 promoter sequence deletion analysis, site-directed mutagenesis, and inhibition by shRNAs demonstrated that HIF1α is a key transcription factor driving pfkfb3 expression following macrophage activation by LPS, whereas synergic induction of pfkfb3 expression observed with the A2 receptor agonists seems to depend on Sp1 activity. Furthermore, levels of phospho-AMP kinase also increase, arguing for increased PFKFB3 activity by phosphorylation in long term LPS-activated macrophages. Taken together, our results show that, in macrophages, endogenously generated adenosine cooperates with bacterial components to increase PFKFB3 isozyme activity, resulting in greater fructose 2,6-bisphosphate accumulation. This process enhances the glycolytic flux and favors ATP generation helping to develop and maintain the long term defensive and reparative functions of the macrophages.

Protection against Fas‐induced liver apoptosis in transgenic mice expressing cyclooxygenase 2 in hepatocytes

Cyclooxygenase‐2 (COX‐2) is upregulated in many cancers, and the prostanoids synthesized increase proliferation, improve angiogenesis, and inhibit apoptosis in several tissues. To explore the function of COX‐2 in liver, transgenic (Tg) mice were generated containing a fusion gene (LIVhCOX‐2) consisting of human COX‐2 cDNA under the control of the human ApoE promoter. Six lines were developed; all of them expressed the LIVhCOX‐2 transgene selectively in hepatocytes. The Tg mice exhibited a normal phenotype, and the increased levels of PGE2 found were due to the constitutively expressed COX‐2. Histological analysis of different tissues and macroscopic examination of the liver showed no differences between wild‐type (Wt) and Tg animals. However, Tg animals were resistant to Fas‐mediated liver injury, as demonstrated by low levels of plasmatic aminotransferases, a lesser caspase‐3 activation, and Bax levels and an increase in Bcl‐2, Mcl‐1, and xIAP proteins, when compared with the Wt animals. Moreover, the resistance to Fas‐mediated apoptosis is suppressed in the presence of COX‐2–selective inhibitors, which prevented prostaglandin accumulation in the liver of Tg mice. Conclusion: These results demonstrate that expression of COX‐2–dependent prostaglandins exerted a protection against liver apoptosis. (HEPATOLOGY 2007;45:631–638.)

Randomized controlled trial of aspiration needle versus automated biopsy device for transjugular liver biopsy.

PURPOSE The efficacy and safety of transjugular liver biopsy used to obtain liver specimens in patients with coagulation disorders have been widely proven. However, histopathologic examination is not always possible because of fragmented samples provided by the aspiration technique. Recently, an automated device with a Tru-Cut-type needle was designed. In this randomized controlled trial, the use of this new device is compared with the traditional method in terms of efficacy and safety. METHOD Fifty-six patients were included in the study; 28 were randomized to undergo the aspiration technique and 28 were randomized to undergo the automated biopsy technique. RESULTS Correct positioning of the device was achieved in 93% of patients undergoing the aspiration technique and 96% of patients undergoing the automated biopsy technique (P = NS). Mean duration of the procedure and total number of passes were significantly higher in the aspiration needle group than in the automated device group (22.6 min +/- 12.6 vs 15.5 min +/- 9.4; P = .03, and 3.3 min +/- 1.9 vs 1.5 min +/- 0.63; P < .001, respectively). The number of portal tracts was significantly higher in the automated device group (4.7 +/- 2.5 vs. 2.7 +/- 3.4; P < .05). Adequate specimens for histopathologic evaluation were obtained in 26 patients in the automated device group and 24 patients in the aspiration needle group (92.8% vs 85.7%; P = NS), but a definite histopathologic diagnosis was more frequently obtained with the automated biopsy device (68% vs 43%; P = .05). No significant differences were observed in complication rates (7.14% vs. 10.7%; P = NS). CONCLUSION The automated biopsy device for transjugular liver biopsy is more effective than an aspiration needle in obtaining good samples for a definite histologic diagnosis.