Kupffer cell-derived interleukin 10 is responsible for impaired bacterial clearance in bile duct-ligated mice

Liver Fibrosis-From Mechanisms of Injury to Modulation of Disease

The Transregional Collaborative Research Center "Organ Fibrosis: From Mechanisms of Injury to Modulation of Disease" (referred to as SFB/TRR57) was funded for 13 years (2009-2021) by the German Research Council (DFG). This consortium was hosted by the Medical Schools of the RWTH Aachen University and Bonn University in Germany. The SFB/TRR57 implemented combined basic and clinical research to achieve detailed knowledge in three selected key questions: (i) What are the relevant mechanisms and signal pathways required for initiating organ fibrosis? (ii) Which immunological mechanisms and molecules contribute to organ fibrosis? and (iii) How can organ fibrosis be modulated, e.g., by interventional strategies including imaging and pharmacological approaches? In this review we will summarize the liver-related key findings of this consortium gained within the last 12 years on these three aspects of liver fibrogenesis. We will highlight the role of cell death and cell cycle pathways as well as nutritional and iron-related mechanisms for liver fibrosis initiation. Moreover, we will define and characterize the major immune cell compartments relevant for liver fibrogenesis, and finally point to potential signaling pathways and pharmacological targets that turned out to be suitable to develop novel approaches for improved therapy and diagnosis of liver fibrosis. In summary, this review will provide a comprehensive overview about the knowledge on liver fibrogenesis and its potential therapy gained by the SFB/TRR57 consortium within the last decade. The kidney-related research results obtained by the same consortium are highlighted in an article published back-to-back in Frontiers in Medicine.

The effect of Crocin on TFAM and PGC-1α expression and Catalase and Superoxide dismutase activities following cholestasis-induced neuroinflammation in the striatum of male Wistar rats

Bile secretion is a physiological function that is disrupted following Bile Duct Ligation (BDL) and induces cholestasis. Cholestasis is a bile flow reduction that induces apoptosis, oxidative stress, and inflammation, and alters the expression of genes. Evidence shows the relationship between cholestasis and neuroinflammation. Cholestasis via attenuating mitochondrial biogenesis and anti-oxidant activity can induce neuroinflammation and apoptosis. Mitochondrial transcriptional factor A (TFAM) and Peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) are involved in mitochondrial biogenesis, and TFAM, PGC-1α, Catalase (CAT), and Superoxide dismutase (SOD) have a role in upregulating antioxidant pathways. On the other hand, many studies have shown the neuroprotective effects of Crocin, the water-soluble carotenoid of Saffron (Crocus sativus L.). In this study, we aimed to investigate the effect of Crocin on the level of TFAM, PGC-1α, CAT, and SOD following cholestasis-induced neuroinflammation in the rat's striatum. Cholestasis was induced by BDL surgery and administration of Crocin was intraperitoneal, at the dose of 30 mg/kg every day, 24 h after BDL surgery up to thirty days. The results showed that TFAM, PGC-1α, and SOD were decreased following cholestasis; while, CAT was increased. In addition, Crocin restored the effects of cholestasis on the level of TFAM, PGC-1α, and SOD. In conclusion, Crocin may have improvement effects on cholestasis-induced neuroinflammation in the rat's striatum.

Human skin-derived ABCB5+ stem cell injection improves liver disease parameters in Mdr2KO mice

Although liver transplantation is a potential effective cure for patients with end-stage liver diseases, this strategy has several drawbacks including high cost, long waiting list, and limited availability of liver organs. Therefore, stem cell-based therapy is presented as an alternative option, which showed promising results in animal models of acute and chronic liver injuries. ABCB5+ cells isolated from skin dermis represent an easy accessible and expandable source of homogenous stem cell populations. In addition, ABCB5+ cells showed already promising results in the treatment of corneal and skin injury. To date, the effect of these cells on liver injury is still unknown. In the current study, sixteen weeks old Mdr2KO mice were i.v. injected with 500,000 ABCB5+ cells using different experimental setups. The effects of cellular therapy on inflammation, fibrosis, apoptosis, and proliferation were analyzed in the collected liver tissues. Toxicity of ABCB5+ cells was additionally investigated in mice with partial liver resection. In vitro, the fibrosis- and inflammatory-modulating effects of supernatant from ABCB5+ cells were examined in the human hepatic stellate cell line (LX-2). Cell injections into fibrotic Mdr2KO mice as well as into mice upon partial liver resection have no signs of toxicity with regard to cell transformation, cellular damage, fibrosis or inflammation as compared to controls. We next investigated the effects of ABCB5+ cells on established biliary liver fibrosis in the Mdr2KO mice. ABCB5+ cells to some extent influenced the shape of the liver inflammatory response and significantly reduced the amount of collagen deposition, as estimated from quantification of sirius red staining. Furthermore, reduced apoptosis and enhanced death compensatory proliferation resulted from ABCB5+ cell transformation. The stem cells secreted several trophic factors that activated TGF-β family signaling in cultured LX-2 hepatic stellate cells (HSCs), therewith shaping cell fate to an αSMAhigh, Vimentinlow phenotype. Taken together, ABCB5+ cells can represent a safe and feasible strategy to support liver regeneration and to reduce liver fibrosis in chronic liver diseases.

Contributing factors and outcomes of burn-associated cholestasis

BACKGROUND & AIMS

Cholestasis often occurs after burn injuries. However, the prevalence of cholestasis and its effect on outcomes in patients with severe burn injuries are unknown. The aim of this study was to describe the course and the burden of cholestasis in a cohort of severely burned adult patients.

METHODS

We investigated the relationship between burn-associated cholestasis (BAC) and clinical outcomes in a retrospective cohort of patients admitted to our unit for severe burn injuries between 2012 and 2015. BAC was defined as an increased level of serum alkaline phosphatase (ALP) ≥1.5x the upper limit of normal (ULN) with an increased level of gamma-glutamyltransferase (GGT) ≥3x ULN, or as an increased level of total bilirubin ≥2x ULN.

RESULTS

A total of 214 patients were included: 111 (52%) patients developed BAC after a median (IQR) stay of 9 (5-16) days. At 90 days, the mortality rate was 20%, including 34 and 9 patients with and without BAC (p <0.001), respectively, which corresponded to a 2.5-fold higher (95% CI 1.2-5.2, p = 0.012) risk of 90-day mortality for patients with BAC. After being adjusted for severity of illness, patients with BAC, hyperbilirubinemia and without elevated ALP and GGT levels had a hazard ratio of 4.51 (95% CI 1.87-10.87) for 90-day mortality. BAC was associated with the severity of the burn injury, shock and bacteraemia. BAC was present in 38 (51%) patients at discharge, and 7 (18%) patients had secondary sclerosing cholangitis. These patients maintained elevated levels of ALP and GGT that were 5.8x (1.7-15) the ULN and 11x the ULN (4.5-22), respectively, 20 months (3.5-35) after discharge.

CONCLUSION

BAC is prevalent among patients with severe burn injuries and is associated with worse short-term outcomes, especially when total bilirubin levels were increased without elevated ALP and GGT levels. BAC survivors are at risk of developing sclerosing cholangitis.

LAY SUMMARY

Cholestasis is common after burn injuries and is associated with burn severity, sepsis, organ failure and mortality. Patients with hyperbilirubinemia without elevated alkaline phosphatase and gamma-glutamyltransferase levels after the burn injury have a poor prognosis. Patients with burn-associated cholestasis may develop sclerosing cholangitis and secondary biliary cirrhosis.

rhIL-1Ra reduces hepatocellular apoptosis in mice with acute liver failure mainly by inhibiting the activities of Kupffer cells

In clinic, there is still no drug that can significantly improve the survival rate of patients with acute liver failure (ALF). We have confirmed that recombinant human IL-1 receptor antagonist (rhIL-1Ra) significantly improves the survival rate of acetaminophen (APAP)-induced ALF mice by reducing hepatocellular apoptosis. Here, we investigated the mechanism of this and the key target cells of rhIL-1Ra. In vivo, APAP-induced ALF mice were treated with rhIL-1Ra and gadolinium chloride (Gdcl₃), respectively. Survival rates of mice, serum IL-1Ra and IL-1β levels, IL-1 receptor type I (IL-1RI) and CD163 expression in the livers, and the phagocytic activities of Kupffer cells (KCs) were investigated. Additionally, the proliferation of hepatocytes and KCs in co-culture conditions with the serum of ALF mice were investigated in vitro. In this study, a large number of activated large KCs were found in liver lobe region III. Both GdCl₃ and rhIL-1Ra significantly decreased the quantity of large KCs. In all of the mice, hepatocytes and liver non-parenchymal cells other than KCs expressed low levels of IL-1RI, whereas large KCs expressed high levels of IL-1RI. The high ratio of endogenous IL-1Ra/IL-1β was related to rhIL-1Ra function. Additionally, the phagocytic activities of KCs were significantly inhibited by GdCl₃ and rhIL-1Ra. In vitro, the proliferation of hepatocytes in co-culture conditions were significantly inhibited by KCs. In conclusion, large KCs were the key target cells of rhIL-1Ra, and rhIL-1Ra could play its role of reducing hepatocellular apoptosis mainly by inhibiting the activities of KCs.

Anti-inflammatory consequences of bile acid accumulation in virus-infected bile duct ligated mice

Cholestatic patients exhibiting high bile acid serum levels were reported to be more susceptible to bacterial and viral infections. Animal studies in bile duct ligated (BDL) mice suggest that cholestasis leads to an aggravation of hepatic bacterial infections. We have investigated the impact of cholestasis on mouse cytomegalovirus (MCMV)-induced immune responses and viral replication. While MCMV did not aggravate BDL-induced liver damage, BDL markedly reduced MCMV-triggered chemokine expression and immune cell recruitment to the liver. MCMV-infected BDL mice showed diminished trafficking of Ly6C+/F4/80+ myeloid cells and NK1.1+ NK cells to the liver compared to MCMV infected control mice. Moreover, virus-driven expression of CCL7, CCL12, CXCL9 and CXCL10 was clearly impaired in BDL- compared to sham-operated mice. Furthermore, production of the anti-inflammatory cytokine IL-10 was massively augmented in infected BDL mice. In contrast, intra- and extrahepatic virus replication was unaltered in BDL-MCMV mice when compared to sham-MCMV mice. Cholestasis in the BDL model severely impaired pathogen-induced chemokine expression in the liver affecting CCR2- and CXCR3-dependent cell trafficking. Cholestasis resulted in reduced recruitment of inflammatory monocytes and NK cells to the liver.

Reprogramming of pro-inflammatory human macrophages to an anti-inflammatory phenotype by bile acids

Cholestasis is caused by autoimmune reactions, drug-induced hepatotoxicity, viral infections of the liver and the obstruction of bile ducts by tumours or gallstones. Cholestatic conditions are associated with impaired innate and adaptive immunity, including alterations of the cellular functions of monocytes, macrophages, NK cells and T-cells. Bile acids act as signalling molecules, affecting lipopolysaccharide (LPS)-induced cytokine expression in primary human macrophages. The present manuscript investigates the impact of bile acids, such as taurolithocholic acid (TLC), on the transcriptome of human macrophages in the presence or absence of LPS. While TLC itself has almost no effect on gene expression under control conditions, this compound modulates the expression of 202 out of 865 transcripts in the presence of LPS. Interestingly, pathway analysis revealed that TLC specifically supressed the expression of genes involved in mediating pro-inflammatory effects, phagocytosis, interactions with pathogens and autophagy as well as the recruitment of immune cells, such as NK cells, neutrophils and T cells. These data indicate a broad influence of bile acids on inflammatory responses and immune functions in macrophages. These findings may contribute to the clinical observation that patients with cholestasis present a lack of response to bacterial or viral infections.

Mechanisms of bile acid mediated inflammation in the liver

Bile acids are synthesized in the liver and are the major component in bile. Impaired bile flow leads to cholestasis that is characterized by elevated levels of bile acid in the liver and serum, followed by hepatocyte and biliary injury. Although the causes of cholestasis have been extensively studied, the molecular mechanisms as to how bile acids initiate liver injury remain controversial. In this chapter, we summarize recent advances in the pathogenesis of bile acid induced liver injury. These include bile acid signaling pathways in hepatocytes as well as the response of cholangiocytes and innate immune cells in the liver in both patients with cholestasis and cholestatic animal models. We focus on how bile acids trigger the production of molecular mediators of neutrophil recruitment and the role of the inflammatory response in this pathological process. These advances point to a number of novel targets where drugs might be judged to be effective therapies for cholestatic liver injury.

The histone methyltransferase Suv39h2 contributes to nonalcoholic steatohepatitis in mice

Uncontrolled inflammatory response highlights the central theme of nonalcoholic steatohepatitis (NASH), a growing global pandemic. Hepatocytes and macrophages represent two major sources of hepatic inflammation during NASH pathogenesis, contributing to excessive synthesis of proinflammatory mediators. The epigenetic mechanism that accounts for the activation of hepatocytes and macrophages in this process remains obscure. Here, we report that compared to wild-type littermates, mice with a deficiency in the histone H3K9 methyltransferase suppressor of variegation 39 homolog 2 (Suv39h2, knockout) exhibited a less severe form of NASH induced by feeding with a high-fat, high-carbohydrate diet. Pro-NASH stimuli increased Suv39h2 expression in cell culture, in mice, and in human livers. In hepatocytes, Suv39h2 bound to the Sirt1 gene promoter and repressed Sirt1 transcription. Suv39h2 deficiency normalized Sirt1 expression, allowing nuclear factor kappa B/p65 to become hypoacetylated and thus dampening nuclear factor kappa B-dependent transcription of proinflammatory mediators. In macrophages, Suv39h2-mediated repression of peroxisome proliferator-activated receptor gamma transcription favored a proinflammatory M1 phenotype over an anti-inflammatory M2 phenotype, thereby elevating hepatic inflammation.

CONCLUSION

Suv39h2 plays a pivotal role in the regulation of inflammatory response in hepatocytes and macrophages, contributing to NASH pathogenesis. (Hepatology 2017;65:1904-1919).

Gut microbial translocation corrupts myeloid cell function to control bacterial infection during liver cirrhosis

OBJECTIVE

Patients with liver cirrhosis suffer from increased susceptibility to life-threatening bacterial infections that cause substantial morbidity.

METHODS

Experimental liver fibrosis in mice induced by bile duct ligation or CCl₄ application was used to characterise the mechanisms determining failure of innate immunity to control bacterial infections.

RESULTS

In murine liver fibrosis, translocation of gut microbiota induced tonic type I interferon (IFN) expression in the liver. Such tonic IFN expression conditioned liver myeloid cells to produce high concentrations of IFN upon intracellular infection with Listeria that activate cytosolic pattern recognition receptors. Such IFN-receptor signalling caused myeloid cell interleukin (IL)-10 production that corrupted antibacterial immunity, leading to loss of infection-control and to infection-associated mortality. In patients with liver cirrhosis, we also found a prominent liver IFN signature and myeloid cells showed increased IL-10 production after bacterial infection. Thus, myeloid cells are both source and target of IFN-induced and IL-10-mediated immune dysfunction. Antibody-mediated blockade of IFN-receptor or IL-10-receptor signalling reconstituted antibacterial immunity and prevented infection-associated mortality in mice with liver fibrosis.

CONCLUSIONS

In severe liver fibrosis and cirrhosis, failure to control bacterial infection is caused by augmented IFN and IL-10 expression that incapacitates antibacterial immunity of myeloid cells. Targeted interference with the immune regulatory host factors IL-10 and IFN reconstitutes antibacterial immunity and may be used as therapeutic strategy to control bacterial infections in patients with liver cirrhosis.

An Agent-Based Model of a Hepatic Inflammatory Response to Salmonella: A Computational Study under a Large Set of Experimental Data

We present an agent-based model (ABM) to simulate a hepatic inflammatory response (HIR) in a mouse infected by Salmonella that sometimes progressed to problematic proportions, known as "sepsis". Based on over 200 published studies, this ABM describes interactions among 21 cells or cytokines and incorporates 226 experimental data sets and/or data estimates from those reports to simulate a mouse HIR in silico. Our simulated results reproduced dynamic patterns of HIR reported in the literature. As shown in vivo, our model also demonstrated that sepsis was highly related to the initial Salmonella dose and the presence of components of the adaptive immune system. We determined that high mobility group box-1, C-reactive protein, and the interleukin-10: tumor necrosis factor-α ratio, and CD4+ T cell: CD8+ T cell ratio, all recognized as biomarkers during HIR, significantly correlated with outcomes of HIR. During therapy-directed silico simulations, our results demonstrated that anti-agent intervention impacted the survival rates of septic individuals in a time-dependent manner. By specifying the infected species, source of infection, and site of infection, this ABM enabled us to reproduce the kinetics of several essential indicators during a HIR, observe distinct dynamic patterns that are manifested during HIR, and allowed us to test proposed therapy-directed treatments. Although limitation still exists, this ABM is a step forward because it links underlying biological processes to computational simulation and was validated through a series of comparisons between the simulated results and experimental studies.

Pathogenesis of Kupffer Cells in Cholestatic Liver Injury

Kupffer cells are the resident macrophages in the liver. They are located in hepatic sinusoid, which allows them to remove foreign materials, pathogens, and apoptotic cells efficiently. Activated Kupffer cells secrete various mediators, including cytokines and chemokines, to initiate immune responses, inflammation, or recruitment of other liver cells. Bile duct ligation (BDL) surgery in rodents is often studied as an animal model of cholestatic liver disease, characterized by obstruction of bile flow. BDL mice show altered functional activities of Kupffer cells compared with sham-operated mice, including elevated cytokine secretion and impaired bacterial clearance. Various mediators produced by other liver cells can regulate Kupffer cell activation, which suggest that Kupffer cells orchestrate with other liver cells to relay inflammatory signals and to maintain liver homeostasis during BDL-induced liver injury. Blocking or depletion of Kupffer cells, an approach for the treatment of liver diseases, has shown controversial implications. Procedures in Kupffer cell research have limitations and may produce various results in Kupffer cell research. It is important, however, to reveal underlying mechanisms of activation and functions of Kupffer cells, followed by hepatic inflammation and fibrosis. This review summarizes present Kupffer cell studies in cholestatic liver injury.

Hepatic stellate cells regulate liver immunity to visceral leishmaniasis through P110δ-dependent induction and expansion of regulatory T cells in mice

Visceral leishmaniasis (VL) is associated with severe immune dysfunction and if untreated leads to death. Because the liver is one of the primary target organs in VL, unraveling the mechanisms governing the local hepatic immune response is important for understanding the immunopathogenesis of VL. We previously reported that mice with inactivating knockin mutation in the p110δ gene (p110δ(D910A) ) are resistant to VL, due in part to impaired regulatory T-cell (Treg) expansion. In this study, we investigated the mechanism of this resistance by focusing on hepatic stellate cells (HSCs), which are known to regulate Treg induction and expansion. We show that HSCs are infected with Leishmania donovani in vivo and in vitro and that this infection leads to the production of interleukin-2, interleukin-6, and transforming growth factor-β, cytokines known to induce Tregs. We further demonstrate that L. donovani infection leads to expansion of HSCs in a p110δ-dependent manner and that this correlated with proliferation of hepatic Tregs in vivo. In vitro studies clearly show that L. donovani-infected HSCs induce CD4(+) T cells to become Tregs and expand Tregs in a p110δ-dependent manner. Targeted depletion of HSCs during infection caused a dramatic reduction in liver Treg numbers and proliferation, which was associated with a decrease in interleukin-10 production by hepatic T cells and a more efficient parasite control.

CONCLUSION

These results demonstrate the critical role of HSCs in the pathogenesis of VL and suggest that the enhanced resistance of p110δ(D910A) mice to L. donovani infection is due in part to impaired expansion and inability of their HSCs to induce and expand Tregs in the liver.

Fatty acid binding protein 7 regulates phagocytosis and cytokine production in Kupffer cells during liver injury

Kupffer cells (KCs) are involved in the progression of liver diseases such as hepatitis and liver cancer. Several members of the fatty acid binding proteins (FABPs) are expressed by tissue macrophages, and FABP7 is localized only in KCs. To clarify the role of FABP7 in the regulation of KC function, we evaluated pathological changes of Fabp7 knockout mice during carbon tetrachloride-induced liver injury. During liver injury in Fabp7 knockout mice, serum liver enzymes were increased, cytokine expression (tumor necrosis factor-α, monocyte chemoattractant protein-1, and transforming growth factor-β) was decreased in the liver, and the number of KCs in the liver necrotic area was significantly decreased. Interestingly, in the FABP7-deficient KCs, phagocytosis of apoptotic cells was impaired, and expression of the scavenger receptor CD36 was markedly decreased. In chronic liver injury, Fabp7 knockout mice showed less fibrogenic response to carbon tetrachloride compared with wild-type mice. Taken together, FABP7 is involved in the liver injury process through its regulation of KC phagocytic activity and cytokine production. Such modulation of KC function by FABP7 may provide a novel therapeutic approach to the treatment of liver diseases.

Deficiency of p110δ isoform of the phosphoinositide 3 kinase leads to enhanced resistance to Leishmania donovani

Background

Visceral leishmaniasis is the most clinically relevant and dangerous form of human leishmaniasis. Most traditional drugs for treatment of leishmaniasis are toxic, possess many adverse reactions and drug resistance is emerging. Therefore, there is urgent need for identification of new therapeutic targets. Recently, we found that mice with an inactivating knock-in mutation in the p110δ isoform of pi3k, (p110δ^d910a) are hyper resistant to L. major, develop minimal cutaneous lesion and rapidly clear their parasite. Here, we investigated whether pi3k signaling also regulates resistance to L. donovani, one of the causative agents of visceral leishmaniasis.

Methodology/Principal Findings

WT and p110δ^D910A mice (on a BALB/c background) were infected with L. donovani. At different time points, parasite burden and granuloma formation were assessed. T and B cell responses in the liver and spleen were determined. In addition, Tregs were expanded in vivo and its impact on resistance was assessed. We found that p110δ^D910A mice had significantly reduced splenomegaly and hepatomegaly and these organs harbored significantly fewer parasites than those of WT mice. Interestingly, infected p110δ^D910A mice liver contains fewer and less organized granulomas than their infected WT counterparts. Cells from p110δ^D910A mice were significantly impaired in their ability to produce cytokines compared to WT mice. The percentage and absolute numbers of Tregs in infected p110δ^D910A mice were lower than those in WT mice throughout the course of infection. In vivo expansion of Tregs in infected p110δ^D910A mice abolished their enhanced resistance to L. donovani infection.

Conclusions/Significance

Our results indicate that the enhanced resistance of p110δ^D910A mice to L. donovani infection is due to impaired activities of Tregs. They further show that resistance to Leishmania in the absence of p110δ signaling is independent of parasite species, suggesting that targeting the PI3K signaling pathway may be useful for treatment of both visceral and cutaneous leishmaniasis.

Visceral leishmaniasis (VL) is the most dangerous form of human leishmaniasis in terms of mortality and morbidity and is spreading to several non-endemic areas because of global traveling and military conflicts. The emergence of Leishmania-HIV coinfection and increased prevalence of drug resistant strains have compounded an already bad situation. In addition, the drugs available are toxic, expensive and have several side effects. Therefore, a detailed understanding of protective immune response is extremely important in order to identify new therapeutic targets. The phosphoinositide 3 kinase (PI3K) family of enzymes mediate several important immunologic and physiologic cellular process including proliferation, differentiation, growth and host defense. We previously showed that genetic inactivation of the p110δ isoform of PI3K results in resistant to L. major (the causative agent of cutaneous leishmaniasis (CL)). Here, we investigate the role of PI3K in immunity to VL and the mechanisms underlying its protective effect. Collectively, our results demonstrate that signaling via the p110δ also regulates immunity to L. donovani, an effect that is dependent on the impact of p110δ signaling on expansion and function of regulatory T cells in vivo. Thus, our studies suggest that targeting the p110δ pathway may be a novel therapeutic strategy for controlling VL and CL.

The quandary of preresection biliary drainage for pancreatic cancer

Surgery in patients with obstructive jaundice caused by a tumor in the pancreatic head area is associated with a higher risk of postoperative complications. Preoperative biliary drainage was introduced in an attempt to improve the general condition and reduce morbidity and mortality. Extensive experimental studies have been performed to analyze the beneficial effect of biliary drainage and showed improvement in liver function, nutritional status, and cell-mediated immune function as well as reduction in mortality. However, despite the results seen in the experimental studies, clinical studies reported both beneficial and adverse effects, and most studies advised against routinely performing preoperative biliary drainage. To add clarity to the ongoing controversy, a recent randomized controlled trial was performed and reported more overall complications in patients with jaundice who underwent preoperative biliary drainage followed by surgery compared to those who underwent surgery alone. Many of these complications were stent related. Like most clinical studies, a plastic stent was used to initiate biliary drainage. Patients with jaundice because of a tumor in the pancreatic head area without locoregional irresectability or metastases should be candidates for early surgery. Preoperative biliary drainage should not be performed routinely. However, some selected patients might benefit from preoperative biliary drainage, in cases of severe jaundice, neoadjuvant therapy, or postponed surgery due to logistics. In these cases, the use of metal biliary stents is indicated.

Regulatory T cells enhance susceptibility to experimental Trypanosoma congolense infection independent of mouse genetic background

Background

BALB/c mice are highly susceptible while C57BL/6 are relatively resistant to experimental Trypanosoma congolense infection. Although regulatory T cells (Tregs) have been shown to regulate the pathogenesis of experimental T. congolense infection, their exact role remains controversial. We wished to determine whether Tregs contribute to distinct phenotypic outcomes in BALB/c and C57BL/6 mice and if so how they operate with respect to control of parasitemia and production of disease-exacerbating proinflammatory cytokines.

Methodology/Findings

BALB/c and C57BL/6 mice were infected intraperitoneally (i.p) with 10³T. congolense clone TC13 and both the kinetics of Tregs expansion and intracellular cytokine profiles in the spleens and livers were monitored directly ex vivo by flow cytometry. In some experiments, mice were injected with anti-CD25 mAb prior or post T. congolense infection or adoptively (by intravenous route) given highly enriched naïve CD25⁺ T lymphocytes prior to T. congolense infection and the inflammatory cytokine/chemokine levels and survival were monitored. In contrast to a transient and non significant increase in the percentages and absolute numbers of CD4⁺CD25⁺Foxp3⁺ T cells (Tregs) in C57BL/6 mouse spleens and livers, a significant increase in the percentage and absolute numbers of Tregs was observed in spleens of infected BALB/c mice. Ablation or increasing the number of CD25⁺ cells in the relatively resistant C57BL/6 mice by anti-CD25 mAb treatment or by adoptive transfer of CD25⁺ T cells, respectively, ameliorates or exacerbates parasitemia and production of proinflammatory cytokines.

Conclusion

Collectively, our results show that regulatory T cells contribute to susceptibility in experimental murine trypanosomiasis in both the highly susceptible BALB/c and relatively resistant C57BL/6 mice.

BALB/c mice are highly susceptible while C57BL/6 is relatively resistant to experimental Trypanosoma congolense infection. Acute death observed in infected BALB/c mice is usually associated with the excessive production of pro-inflammatory cytokines. Regulatory T cells (Tregs) have been shown to play a significant role in the pathogenesis of many diseases including those caused by parasites. However, the role of Tregs in the pathogenesis of T. congolense infection remains unclear. We were interested in addressing the following questions: Do Tregs contribute to the distinct phenotypic outcomes observed in T. congolense-infected BALB/c and C57BL/6 mice? If so, where and how do they operate with respect to parasitemia and cytokine response? By selectively altering the numbers of these cells either by targeted depletion with monoclonal antibody or adoptive transfer of highly enriched naïve CD25⁺ cells prior to infection, we show that Tregs impairs efficient parasite control and impacts on production of disease-exacerbating proinflammatory cytokines. Collectively, our findings suggest that Tregs contribute to enhanced susceptibility to experimental T. congolense infection in mice.

Effects of hepatocyte CD14 upregulation during cholestasis on endotoxin sensitivity

Cholestasis is frequently related to endotoxemia and inflammatory response. Our previous investigation revealed a significant increase in plasma endotoxin and CD14 levels during biliary atresia. We therefore propose that lipopolysacharides (LPS) may stimulate CD14 production in liver cells and promote the removal of endotoxins. The aims of this study are to test the hypothesis that CD14 is upregulated by LPS and investigate the pathophysiological role of CD14 production during cholestasis. Using Western blotting, qRT-PCR, and promoter activity assay, we demonstrated that LPS was associated with a significant increase in CD14 and MD2 protein and mRNA expression and CD14 promoter activity in C9 rat hepatocytes but not in the HSC-T6 hepatic stellate cell line in vitro. To correlate CD14 expression and endotoxin sensitivity, in vivo biliary LPS administration was performed on rats two weeks after they were subjected to bile duct ligation (BDL) or a sham operation. CD14 expression and endotoxin levels were found to significantly increase after LPS administration in BDL rats. These returned to basal levels after 24 h. In contrast, although endotoxin levels were increased in sham-operated rats given LPS, no increase in CD14 expression was observed. However, mortality within 24 h was more frequent in the BDL animals than in the sham-operated group. In conclusion, cholestasis and LPS stimulation were here found to upregulate hepatic CD14 expression, which may have led to increased endotoxin sensitivity and host proinflammatory reactions, causing organ failure and death in BDL rats.

Creation of reversible cholestatic rat model

Cholestasis is a clinical condition commonly encountered by both surgeons and gastroenterologists. Cholestasis can cause various physiological changes and affect the nutritional status and surgical outcomes. Study of the pathophysiological changes occurring in the liver and other organs is of importance. Various studies have been done in cholestatic rat models. We used a reversible cholestatic rat model in our recent study looking at the role of methylprednisolone in the ischemia reperfusion injury. Various techniques for creation of a reversible cholestatic model have been described. Creation of a reversible cholestatic rat model can be challenging in view of the smaller size and unique hepatopancreatobiliary anatomy in rats. This video article demonstrates the creation of a reversible cholestatic model. This model can be used in various studies, such as looking at the changes in nutritional, physiological, pathological, histological and immunological changes in the gastrointestinal tract. This model can also be used to see the effects of cholestasis and various therapeutic interventions on major hepatic surgeries.

Interleukin-17-mediated control of parasitemia in experimental Trypanosoma congolense infection in mice

BALB/c mice are highly susceptible to experimental Trypanosoma congolense infections, whereas C57BL/6 mice are relatively resistant. Infected highly susceptible BALB/c mice die of systemic inflammatory response syndrome. Because interleukin-17 (IL-17) and Th17 cells regulate inflammatory responses, we investigated their role in the pathogenesis of experimental African trypanosomiasis in mice. We show that the production of IL-17 by spleen and liver cells and the serum IL-17 level increased after T. congolense infection in mice. Interestingly, infected highly susceptible BALB/c mice produced more IL-17 and had more Th17 cells than infected relatively resistant C57BL/6 mice. Paradoxically, neutralization of IL-17 with anti-IL-17 monoclonal antibody in vivo induced higher parasitemia in both the susceptible and the relatively resistant mice. Interestingly, anti-IL-17 antibody-treated mice had higher serum levels of alanine aminotransferase and aspartate aminotransferase, and the production of IL-10 and nitric oxide by liver cells was markedly decreased. Moreover, recombinant IL-17-treated mice exhibited significantly faster parasite control and lower peak parasitemia compared to control mice. Collectively, these results suggest that the IL-17/Th17 axis plays a protective role in murine experimental African trypanosomiasis.

Effects of carbon dioxide pneumoperitoneum on hepatic function in obstructive jaundice: an experimental study in a rat model

BACKGROUND AND AIMS

The physiology of the patient during laparoscopy differs from that of open surgery. Both pneumoperitoneum and obstructive jaundice impair the hepatic function, but the combined insult has not been previously examined. In this study, we aimed to investigate the effects of carbon dioxide (CO(2)) pneumoperitoneum on hepatic function in a rat model of obstructive jaundice.

METHODS

Forty-four male Sprague-Dawley rats were divided into four groups: group 1 (n = 10), sham-operated group; group 2 (n = 12), obstructive jaundice group; group 3 (n = 10), CO(2) pneumoperitoneum group; and group 4 (n = 12), obstructive jaundice and CO(2) pneumoperitoneum group. Common bile duct was ligated and divided in the obstructive jaundice groups. After 6 days, a 12-mmHg pneumoperitoneum was induced, maintained for 60 min, and released for 120 min. Blood samples were drawn for the measurement of white blood cell and platelet counts, serum liver enzymes (aspartate aminotransferase [AST], alanine aminotransferase [ALT], total bilirubin). Tissue samples were obtained for analyses of malondialdehyde (MDA), glutathione (GSH), and superoxide dismutase (SOD) levels. We evaluated the degree of liver injury on a grading scale from 0 to 4, histopathologically.

RESULTS

Pneumoperitoneum after biliary obstruction resulted in an increase in AST and ALT levels and a decrease in white blood cell and platelet counts. However, changes in liver tissue MDA, GSH, and SOD levels did not correlate with the changes in AST and ALT levels and white blood cell and platelet counts. After sham operation with pneumoperitoneum, the GSH levels in liver homogenate were significantly decreased in the group 3 when compared to the group 2. On the other hand, obstructive jaundice itself caused significant reduction in the SOD activity of liver homogenate in comparison to the group 3. Histopathologically, sinusoidal congestion and vacuolization were more severe in the group 3.

CONCLUSIONS

Alterations in hepatic function occur in pneumoperitoneum applied jaundiced subjects. However, there were no statistically significant differences between the groups 2 and 4 with regard to white blood cell and platelet counts, serum liver enzymes including AST, ALT, and total bilirubin values, MDA and GSH levels and SOD activity of liver homogenate, and histologic damage. These results indicate that there is no additional risk on liver function associated with pneumoperitoneum performed in obstructive jaundice.

Changes of serum cytokines and expression of inducible nitric oxide synthase mRNA by Kupffer cells after relief from obstructive jaundice in rats

AIMS

To investigate the changes of serum endotoxin, tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and inducible nitric oxide synthase (iNOS) expression by Kupffer cells after relief of obstructive jaundice (OJ) by internal biliary drainage (ID) and external biliary drainage (ED) in rats.

MATERIALS AND METHODS

Forty eight adult Sprague Dawley rats were randomly assigned to four groups: OJ, ID, ED and sham operation (SH). Inducible nitric oxide synthase mRNA by the Kupffer cells was detected by reverse transcription polymerase chain reaction. The serum TNF-alpha and IL-6 were measured by enzyme linked immunosorbent assay and endotoxin by kinetic turbidimetric limulus tests.

RESULTS

Serum endotoxin, IL-6 and TNF-alpha levels were significantly elevated in OJ rats compared to that of SH rats (P < 0.01). After relief from OJ, the elevated endotoxin, IL-6 and TNF-alpha levels could be significantly depressed by ID (P < 0.01). However, the serum IL-6 level was increased in ED rats (P < 0.05) and the TNF-alpha level was not depressed by ED. Expression of iNOS mRNA by Kupffer cells was markedly stronger in the OJ group than in the SH group (P = 0.005). After relief from OJ, the iNOS mRNA expression was suppressed by ID (P = 0.139, ID vs OJ). However, the iNOS mRNA expression was promoted by ED (P = 0.321 ED vs OJ; P = 0.016 ED vs SH).

CONCLUSIONS

The levels of serum endotoxin, TNF-alpha and IL-6 and the expression of iNOS mRNA by Kupffer cells were increased in rats with obstructive jaundice. Internal biliary drainage could entirely reverse the changes, but external drainage only partially did.

Cerebral microglia recruit monocytes into the brain in response to tumor necrosis factoralpha signaling during peripheral organ inflammation

In inflammatory diseases occurring outside the CNS, communication between the periphery and the brain via humoral and/or neural routes results in central neural changes and associated behavioral alterations. We have recently identified another immune-to-CNS communication pathway in the setting of organ-centered peripheral inflammation: namely, the entrance of immune cells into the brain. In our current study, using a mouse model of inflammatory liver injury, we have confirmed the significant infiltration of activated monocytes into the brain in mice with hepatic inflammation and have defined the mechanism that mediates this trafficking of monocytes. Specifically, we show that in the presence of hepatic inflammation, mice demonstrate elevated cerebral monocyte chemoattractant protein (MCP)-1 levels, as well as increased numbers of circulating CCR2-expressing monocytes. Cerebral recruitment of monocytes was abolished in inflamed mice that lacked MCP-1/CCL2 or CCR2. Furthermore, in mice with hepatic inflammation, microglia were activated and produced MCP-1/CCL2 before cerebral monocyte infiltration. Moreover, peripheral tumor necrosis factor (TNF)alpha signaling was required to stimulate microglia to produce MCP-1/CCL2. TNFalpha signaling via TNF receptor 1 (TNFR1) is required for these observed effects since in TNFR1 deficient mice with hepatic inflammation, microglial expression of MCP-1/CCL2 and cerebral monocyte recruitment were both markedly inhibited, whereas there was no inhibition in TNFR2 deficient mice. Our results identify the existence of a novel immune-to-CNS communication pathway occurring in the setting of peripheral organ-centered inflammation which may have specific implications for the development of alterations in cerebral neurotransmission commonly encountered in numerous inflammatory diseases occurring outside the CNS.

The Rho-kinase inhibitor Y-27632 inhibits cholestasis-induced platelet interactions in the hepatic microcirculation

Bile duct obstruction is associated with hepatic accumulation of leukocytes and liver injury. Emerging data suggest that platelets may play an important role in tissue damage and inflammation. Herein, we characterized the platelet response in cholestatic liver injury and evaluated the role of Rho-kinase signaling. For this purpose, C57BL/6 mice were treated with the Rho-kinase inhibitor Y-27632 (10 mg/kg) and vehicle before undergoing bile duct ligation (BDL) for 12 h. Platelet rolling and adhesion, formation of platelet aggregates as well as microvascular perfusion in the liver were analyzed using intravital fluorescence microscopy. Liver damage was monitored by measuring serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Administration of Y-27632 reduced the BDL-associated increase of ALT and AST by 95% and 89%, respectively. The inhibition of Rho-kinase also reduced cholestasis-induced platelet rolling and adhesion by more than 46% and 73% in postsinusoidal venules and platelet adhesion in sinusoids by 60%. In addition, Y-27632 decreased platelet aggregation in hepatic sinusoids and postsinusoidal venules by 69% and 81%. BDL caused a significant reduction of hepatic microvascular perfusion. Importantly, pretreatment with Y-27632 restored sinusoidal perfusion in cholestatic animals. Our findings demonstrate that Rho-kinase regulates multiple aspects of platelet interaction in the microcirculation of cholestatic animals. Moreover, inhibition of Rho-kinase signaling not only attenuates platelet responses but also maintains microvascular perfusion and protects against hepatocellular injury in cholestasis. Thus, targeting Rho-kinase signaling may be an effective way to protect against platelet-mediated liver injury in obstructive jaundice.

Preoperative biliary drainage in patients with obstructive jaundice: history and current status

RATIONALE

Preoperative biliary drainage (PBD) has been introduced to improve outcome after surgery in patients suffering from obstructive jaundice due to a potentially resectable proximal or distal bile duct/pancreatic head lesion. In experimental models, PBD is almost exclusively associated with beneficial results: improved liver function and nutritional status; reduction of systemic endotoxemia; cytokine release; and, as a result, an improved immune response. Mortality was significantly reduced in these animal models. Human studies show conflicting results.

FINDINGS

For distal obstruction, currently the "best-evidence" available clearly shows that routine PBD does not yield the appreciated improvement in postoperative morbidity and mortality in patients undergoing resection. Moreover, PBD harbors its own complications. However, most of the available data are outdated or suffer from methodological deficits.

CONCLUSION

The highest level of evidence for PBD to be performed in proximal obstruction, as well as over the preferred mode, is lacking but, nevertheless, assimilated in the treatment algorithm for many centers. Logistics and waiting lists, although sometimes inevitable, could be factors that might influence the decision to opt for PBD, as well as an extended diagnostic workup with laparoscopy (on indication) or scheduled preoperative chemotherapy.

Choleretic effect of inchinkoto, a herbal medicine, on livers of patients with biliary obstruction due to bile duct carcinoma

AIM

To investigate the choleretic effects of inchinkoto (ICKT) on livers of patients with biliary obstruction due to bile duct carcinoma.

METHODS

Twenty-seven patients with bile duct carcinoma who were due to undergo biliary drainage and subsequent major hepatectomy were randomly assigned to preoperative ICKT (n = 13) or untreated (n = 14) groups. ICKT was administered from the day of admission until one day before surgery. Changes in bile constituents, expression of multidrug resistance-associated protein (MRP) 2, MRP3 and MRP4 in the liver, and the incidence of postoperative complications were included as end-points.

RESULTS

The biliary concentration of total bilirubin was significantly increased after administration of ICKT (23.7 +/- 2.8 mg/dL before ICKT; 34.0 +/- 4.0 mg/dL after ICKT, P < 0.05). The biliary concentration of total bile acids was also significantly increased. Protein levels of MRP2 and MRP3 in the crude plasma membrane fraction of livers of treated patients were significantly higher than those without treatment. MRP2 staining in the livers of patients without ICKT treatment was weak and diffuse around the bile canaliculi, whereas staining in patients with ICKT treatment was strong and restricted to the bile canaliculi.

CONCLUSION

ICKT exerts a choleretic effect on the livers of patients with biliary obstruction. This beneficial effect was associated with increased expression of MRP2. ICKT thus has therapeutic potential for treatment for obstructive cholestasis due to bile duct carcinoma.

Vitamin D3 modulates the expression of bile acid regulatory genes and represses inflammation in bile duct-ligated mice

Vitamin D receptor (VDR), a nuclear receptor that regulates calcium homeostasis, has been found to function as a receptor for secondary bile acids. Because the in vivo role of VDR in bile acid metabolism remains unknown, we investigated the effect of VDR activation in a mouse model of cholestasis. We treated mice with 1alpha-hydroxyvitamin D(3) [1alpha(OH)D(3)] after bile duct ligation (BDL) and examined mRNA expression and cytokine levels. 1alpha(OH)D(3) treatment altered the expression of genes involved in bile acid synthesis and transport in the liver, kidney, and intestine but did not decrease bile acid levels in the plasma and liver of BDL mice. 1alpha(OH)D(3) treatment suppressed mRNA expression of proinflammatory cytokines in the liver and strongly decreased the plasma levels of proinflammatory cytokines in BDL mice. These findings indicate that 1alpha(OH)D(3) regulates a network of bile acid metabolic genes and represses proinflammatory cytokine expression in BDL mice. VDR ligands have the potential to prevent the cholestasis-induced inflammatory response.

Niemann-Pick C1 protects against atherosclerosis in mice via regulation of macrophage intracellular cholesterol trafficking

Niemann-Pick C1 (NPC1) is a key participant in cellular cholesterol trafficking. Loss of NPC1 function leads to defective suppression of SREBP-dependent gene expression and failure to appropriately activate liver X receptor-mediated (LXR-mediated) pathways, ultimately resulting in intracellular cholesterol accumulation. To determine whether NPC1 contributes to regulation of macrophage sterol homeostasis in vivo, we examined the effect of NPC1 deletion in BM-derived cells on atherosclerotic lesion development in the Ldlr-/- mouse model of atherosclerosis. High-fat diet-fed chimeric Npc1-/- mice reconstituted with Ldlr-/-Npc1-/- macrophages exhibited accelerated atherosclerosis despite lower serum cholesterol compared with mice reconstituted with wild-type macrophages. The discordance between the low serum lipoprotein levels and the presence of aortic atherosclerosis suggested that intrinsic alterations in macrophage sterol metabolism in the chimeric Npc1-/- mice played a greater role in atherosclerotic lesion formation than did serum lipoprotein levels. Macrophages from chimeric Npc1-/- mice showed decreased synthesis of 27-hydroxycholesterol (27-HC), an endogenous LXR ligand; decreased expression of LXR-regulated cholesterol transporters; and impaired cholesterol efflux. Lower 27-HC levels were associated with elevated cholesterol oxidation products in macrophages and plasma of chimeric Npc1-/- mice and with increased oxidative stress. Our results demonstrate that NPC1 serves an atheroprotective role in mice through regulation of LXR-dependent cholesterol efflux and mitigation of cholesterol-induced oxidative stress in macrophages.

Characterization of time-related changes after experimental bile duct ligation

BACKGROUND

Although bile duct ligation (BDL) in mice is used to study cholestasis, a detailed description of this animal model is lacking. The aim of this study was to define specific phases of acute and chronic injury and repair in the different cellular compartments of the liver.

METHODS

C57BL/6 mice underwent BDL or sham laparotomy, and serum and liver tissue were analysed between 8 h and 6 weeks later.

RESULTS

Biliary infarcts and alanine aminotransferase levels revealed acute hepatocellular injury peaking at days 2-3, paralleled by enhanced transcription of pro-proliferative mediators and followed by a distinct peak of hepatocellular proliferation at day 5. Cholangiocellular proliferation occurred in large bile ducts on days 2-3 and in small bile ducts on day 5. Neutrophil infiltration occurred within 8 h, with neutrophils remaining the predominant immune cell type until day 3. Acute injury was followed by continuous tissue repair, lymphocyte and Kupffer cell infiltration, and accumulation of collagen during the second week. Thereafter, the number of alpha-smooth muscle actin-positive cells and the expression of transforming growth factor beta1, tissue inhibitor of metalloproteinases 1 and procollagen (I) decreased, and liver fibrosis stabilized.

CONCLUSION

BDL elicits dynamic changes in mouse liver. The chronological dissection and quantification of these events identified specific phases of acute and chronic cholestatic liver injury.

Preoperative biliary drainage before resection for cholangiocarcinoma (Pro)

Three types of preoperative biliary drainage (BD): percutaneous transhepatic (PTBD), endoscopic (EBD), and endoscopic nasobiliary (ENBD) can be indicated before resection of cholangiocarcinoma. However, three randomized controlled trials (RCTs) have revealed that preoperative PTBD does not improve perioperative results. Other RCTs have revealed that preoperative EBD for malignant obstructive jaundice has no demonstrable benefit and after EBD for hilar cholangiocarcinoma there are highly developed infectious complications. Most patients with distal cholangiocarcinoma undergo pancreatoduodenectomy (PD) without preoperative BD. However, no RCTs have been performed to clarify the safety of major hepatectomy without preoperative BD for cholestatic patients with hilar cholangiocarcinoma. Furthermore, preoperative intrahepatic segmental cholangitis is a prognostic factor in the outcome of major hepatectomy for biliary cancer. Preoperative BD has another purpose in the preoperative management of patients with hilar cholangiocarcinoma. Selective cholangiography via ENBD and/or PTBD catheters provides precise information about the complicated segmental anatomy of the intrahepatic bile ducts and extent of cancer along the separated segmental bile ducts, which contributes toward designing a type of resective procedure. RCTs in biliary cancer patients undergoing major hepatectomy have revealed that bile replacement during external biliary drainage and perioperative synbiotic treatment can prevent postoperative infectious complications. Although preoperative EBD increases the risk of cholangitis, major hepatectomy combined with preoperative biliary drainage, preferably PTBD and/or ENBD, followed by portal vein embolization has been established as a safer management strategy for perihilar cholangiocarcinoma.

Excessive inflammation but decreased immunological response renders liver susceptible to infection in bile duct ligated mice

BACKGROUND/AIMS

Obstructive jaundice (OJ) is associated with increased surgical morbidity and infectious complication. The aim of the current study was to clarify the mechanism of excessive inflammation and susceptibility to infection in OJ.

METHODS

C57/BL6 mice were subjected to bile duct ligation (BDL) or sham surgery. Expression tumor necrosis factor-alpha, macrophage inflammatory protein-2, monocyte chemoattractant protein-1, inducible protein-10, and interleukin (IL)-10, activation of nuclear factor kappa B, fluorescence activated cell sorter analysis, serum alanine aminotransferase levels, and histology were examined. Survival after lipopolysaccharide (LPS) administration or cecal ligation and puncture 3 or 14 d after surgery was determined. IL-1beta and interferon-gamma expression was examined after LPS administration.

RESULTS

OJ induced nuclear factor kappa B activation and increased expression of macrophage inflammatory protein-2, which caused significant increases in neutrophil recruitment. Serum alanine aminotransferase levels increased consistent with histological observations in OJ. Mononuclear cells were recruited in the liver after BDL associated with monocyte chemoattractant protein-1 up-regulation. The recruitment of NK and T cells was varied, consistent with IP-10 expression during the time course of OJ. IL-10 expression was significantly up-regulated 14 d after BDL. After LPS administration, the mice at 3 d after BDL and at 3 and 14 d after sham surgery were all still alive, but all mice at 14 d after BDL died. After LPS administration, IL-1beta significantly increased in the mice at 14 d after BDL.

CONCLUSIONS

Immune response such as expression of pro- and anti-inflammatory mediators and recruitment of immune cells may thus differ over the time course of OJ. Prolonged OJ may cause excessive inflammation, thus result in susceptibility to infection.

Mechanisms of hepatic regeneration following portal vein embolization and partial hepatectomy: a review

BACKGROUND

Portal vein embolization (PVE) improves outcome following major hepatectomy, and basic studies have presented evidence related to the mechanisms responsible for hepatic regeneration. Hemodynamic changes following PVE are similar to, but slightly different from, those of partial hepatectomy (PH) because arterial flow to the embolized lobe is preserved. However, the process of hepatic regeneration is essentially the same after both PVE and PH. A number of mediators are involved in PVE or PH-induced hepatic regeneration. These include inflammatory cytokines, vasoregulators, growth factors, eicosanoids, and various hormones. These mediators activate a complex network of signal transduction that promotes hepatic regeneration. A variety of conditions have been shown to modulate the function of these mediators and inhibit regeneration. These include biliary obstruction, diabetes, chronic ethanol consumption, malnutrition, gender, aging, and infection.

CONCLUSION

Optimizing these factors, where possible, before PVE or PH, is essential to maximize hypertrophy of the liver. A fuller understanding of hepatic physiology and pathophysiology following PVE or PH may lead to greater functional capacity of the remaining liver and extend the indications for hepatectomy in patients who require large liver volume resection.

Right hepatopancreatoduodenectomy: improvements over 23 years to attain acceptability

BACKGROUND/PURPOSE

Right hepatopancreatoduodenectomy (rt-HPD), a demanding procedure associated with high morbidity and mortality, remains the only curative option for some patients with biliary cancer. We retrospectively analyzed our progress over 23 years in making this operation safer.

METHODS

Fifty-eight patients who had undergone rt-HPD were enrolled. Gallbladder cancer was present in 33 patients and bile duct cancer in 25 patients. Comparisons of short-term results after surgery were made between the 1980s (16 patients), 1990s (28 patients), and 2000 to 2004 (14 patients).

RESULTS

Intraoperative blood loss decreased progressively and significantly. The incidence of pancreatic fistula, and leakage of pancreatojejunostomy and hepaticojejunostomy also decreased, as did the occurrence of liver failure. Infection varied little by decade, but some recent progress may be underway. Mortality decreased, although not significantly.

CONCLUSIONS

Refinements in techniques, imaging, and perioperative management have improved the outlook for patients requiring HPD for cure, but much more remains to be achieved. Our results are not satisfactory, but they may be acceptable, considering the lack of alternative curative treatment.

Tissue microarray analysis of interleukin-20 expression

Knowledge about the biological functions and clinical implications of interleukin (IL)-20, a recently discovered cytokine in the IL-10 family, is still incomplete. Our aim was to determine the distribution of IL-20 expression and to delineate the cell types that express IL-20 in healthy and neoplastic tissue, because this information will significantly affect the exploration of its pathophysiological roles. We used tissue microarray technology and an immunohistochemical survey using an anti-IL-20 monoclonal antibody to examine IL-20 expression in 36 non-neoplastic and 14 neoplastic tissues. IL-20 protein was positively stained in 30 non-neoplastic tissue types and five major cell types: epithelial cells, myoepithelial cells, endothelial cells, macrophages, and skeletal muscle cells. We also found that several types of tumor cells stained positive for IL-20, especially in squamous cell carcinoma of the skin, tongue, esophagus, and lung. Our data provide valuable references for further investigation of the biological functions and clinical implications of IL-20 in humans.

Biliary obstruction selectively expands and activates liver myeloid dendritic cells

Obstructive jaundice is associated with immunologic derangements and hepatic inflammation and fibrosis. Because dendritic cells (DCs) play a major role in immune regulation, we hypothesized that the immunosuppression associated with jaundice may result from the functional impairment of liver DCs. We found that bile duct ligation (BDL) in mice expanded the myeloid subtype of liver DCs from 20 to 80% of total DCs and increased their absolute number by >15-fold. Liver myeloid DCs following BDL, but not sham laparotomy, had increased Ag uptake in vivo, high IL-6 secretion in response to LPS, and enhanced ability to activate T cells. The effects of BDL were specific to liver DCs, as spleen DCs were not affected. Expansion of liver myeloid DCs depended on Gr-1(+) cells, and we implicated monocyte chemotactic protein-1 as a potential mediator. Thus, obstructive jaundice selectively expands liver myeloid DCs that are highly functional and unlikely to be involved with impaired host immune responses.

Endogenous opioid-mediated antinociception in cholestatic mice is peripherally, not centrally, mediated

BACKGROUND/AIMS

Cholestasis is associated with naloxone reversible antinociception and opiate receptor antagonists are used clinically to treat pruritus. Pain and pruritus are closely interrelated and opioids modulate both sensations. Therefore, we undertook a series of experiments to characterize opioid-mediated antinociception in cholestasis and determine if it occurs inside or outside the CNS.

METHODS

Antinociception scores to both thermal and mechanical stimuli were determined in mice with cholestasis due to bile duct resection vs sham controls.

RESULTS

Cholestatic mice demonstrated significant antinociception to both stimuli compared to controls, which was reversible by the opiate receptor antagonist naloxone. The experiments were repeated with a naloxone derivative, which does not cross the blood-brain-barrier (i.e. naloxone methiodide) with similar results, indicating an opioid antinociceptive effect mediated outside of the CNS. Experiments with intraplantar injections of low dose naloxone methiodide confirmed that cholestasis-associated antinociception occurs at the level of cutaneous nerve endings. These findings were supported by findings of increased dermal met-enkephalin expression in cholestatic mice.

CONCLUSIONS

Cholestasis in mice is associated with antinociception due to local effects of endogenous opioids (i.e. met-enkephalin) at the level of sensory nerve endings. These findings may have direct implications in the management of cholestasis associated pruritus.

Kupffer cells abrogate cholestatic liver injury in mice

BACKGROUND & AIMS

Biliary obstruction and cholestasis can cause hepatocellular apoptosis and necrosis. Ligation of the common bile duct in mice provides an excellent model in which to study the underlying mechanisms. Kupffer cells play a key role in modulating the inflammatory response observed in most animal models of liver injury. This study was performed to determine the role of Kupffer cells in the injury attending cholestasis.

METHODS

Mice were not treated or were rendered Kupffer cell-depleted by intravenous inoculation of multilamellar liposome-encapsulated dichloromethylene diphosphonate, the common bile duct was ligated and divided; sham-operated animals served as controls. Similarly, interleukin-6 (IL-6)-deficient and tumor necrosis factor-receptor-deficient mice underwent bile duct ligation (BDL) or sham operations.

RESULTS

Serum alanine transaminase levels were increased in all BDL mice at 3 days after surgery, but were significantly higher in IL-6-deficient mice or mice rendered Kupffer cell-depleted before ligation. Histologic examination of BDL livers showed portal inflammation, neutrophil infiltration, bile duct proliferation, and hepatocellular necrosis. Photoimage analyses confirmed more necrosis in the livers of Kupffer cell-depleted and IL-6-deficient animals. Purified Kupffer cells derived from BDL animals produced more IL-6 in culture. Similarly, Kupffer cells obtained by laser capture microdissection from the livers of BDL mice expressed increased levels of IL-6 messenger RNA. Recombinant mouse IL-6 administered 1 hour before BDL completely reversed the increased liver damage assessed otherwise in Kupffer cell-depleted mice.

CONCLUSIONS

These findings indicate that Kupffer cells abrogate cholestatic liver injury by cytokine-dependent mechanisms that include the production of IL-6.

TNF-alpha-secreting monocytes are recruited into the brain of cholestatic mice

Signaling occurs between the liver and brain in cholestatic liver disease, giving rise to sickness behaviors such as fatigue. However, the signaling pathways involved are poorly defined. Circulating inflammatory mediator levels are increased in cholestasis, leading to speculation that they may be capable of activating circulating immune cells that subsequently could gain access to the brain. Indeed, we have identified that at day 10 after bile duct resection-induced cholestasis, there is activation of circulating monocytes that express tumor necrosis factor alpha (TNF-alpha) in conjunction with increased expression of adhesion molecules by cerebral endothelium. Moreover, using intravital microscopy, we have identified markedly enhanced leukocytes rolling along cerebral endothelial cells, mediated by P-selectin, in bile duct-resected (BDR) but not control mice. In addition, we have identified increased infiltration of monocytes (but not lymphocytes) into the brains of BDR mice and found that these infiltrating monocytes produce TNF-alpha. Furthermore, infiltration of TNF-alpha-secreting monocytes into the brains of cholestatic mice is associated with a broad activation of resident brain macrophages to produce TNF-alpha. In conclusion, cholestasis is associated with an activation of cerebral endothelium that recruits TNF-alpha-producing monocytes into the brain. We hypothesize that enhanced TNF-alpha release within the brain may contribute to the development of cholestasis-associated sickness behaviors, including fatigue.

Altered Kupffer cell function in biliary obstruction

BACKGROUND

An altered Kupffer cell (KC) response is thought to be responsible for the characteristic phenotype observed after biliary obstruction: a phenotype marked by a defect in the hepatic reticuloendothelial system and a hypersensitivity to endotoxin. Few studies, however, have directly examined KC function. We have sought to define the specific alterations in function and phenotype that occur in the KC after biliary obstruction.

METHODS

KCs were isolated from female C57BL/6 mice 4 days after a sham or common bile duct ligation (CBDL) operation. Phagocytosis, oxidative burst potential, and intracellular bacterial killing were measured as markers of reticuloendothelial system function. The KC response to endotoxin was assessed by measuring tumor necrosis factor alpha and interleukin 6 levels in the media after stimulation with lipopolysaccharide (LPS) or with LPS plus LPS-binding protein (LBP).

RESULTS

CBDL KCs demonstrated a significant increase in phagocytic ability and significantly decreased baseline oxidative stress, compared with Shams. The oxidative burst potential, however, was equivalent or higher for CBDL KCs. CBDL KCs also demonstrated increased numbers of viable intracellular bacteria after infection; however, it is unclear if this finding represents impaired intracellular bacterial killing or increased phagocytosis of bacteria. With respect to the KC response to endotoxin, CBDL KCs were found to be less sensitive to the stimulatory effects of LPS alone but were exquisitely sensitive to the effects of LBP. LBP levels were found to be significantly elevated in CBDL animals, and CBDL KCs demonstrated a dose-dependent, exaggerated tumor necrosis factor alpha and interleukin 6 response to LPS administered with LBP.

CONCLUSIONS

KC function is clearly altered after biliary obstruction. Phagocytic ability is actually increased, although the ability of CBDL KCs to kill bacteria within the phagosome remains ill defined. CBDL KCs are exquisitely sensitive to the effects of LBP, and LBP levels are elevated after biliary obstruction. LBP may be responsible for the increased proinflammatory response observed after endotoxin challenge in animals with biliary obstruction.

Hepatic steatosis in HIV/hepatitis C coinfection: prevalence and significance compared with hepatitis C monoinfection

Liver disease in patients coinfected with HIV and hepatitis C virus (HCV) has received increasing attention in recent years. Steatosis is accepted as an important contributor to liver disease in patients with HCV, but despite coinfected patients having several reasons to have steatosis, the prevalence and significance of such changes has received scant attention. We examined steatosis in an unselected cohort of coinfected patients and compared its prevalence and predictors with findings in monoinfected patients, where these relationships have been established. We studied 92 coinfected and 372 monoinfected patients undergoing staging liver biopsy. Baseline characteristics of the two groups differed significantly, pointing at different contributors to steatosis in each. Histological inflammation and fibrosis were very similar in the two groups, but steatosis was less in coinfected patients. Steatosis had a univariate association with fibrosis in both groups, but retained a multivariate association only in monoinfected patients. Other multivariate predictors of steatosis in monoinfected patients were the accepted variables of elevated body mass index, male sex, and genotype 3a infection, as well as age. In coinfected patients, however, age was the only multivariate predictor. Undetectable HIV viral load was associated with steatosis in coinfected patients in univariate analysis, but highly active antiretroviral therapy or its individual components could not be initially linked to steatosis. In conclusion, steatosis is less common in HIV/HCV coinfected patients than similar HCV monoinfected patients, and predictors of steatosis differ between the two groups.