Bilirubin impairs bactericidal activity of neutrophils through an antioxidant mechanism in vitro

Cellular ROS and Antioxidants: Physiological and Pathological Role

Reactive oxygen species (ROS) are highly reactive oxygen derivatives that include free radicals such as superoxide anion radical (O2•-) and hydroxyl radical (HO•), as well as non-radical molecules hydrogen peroxide (H2O2), peroxynitrite (ONOO-), and hypochlorous acid (HOCl) [...].

Inflammatory liver diseases and susceptibility to sepsis

Patients with inflammatory liver diseases, particularly alcohol-associated liver disease and metabolic dysfunction-associated fatty liver disease (MAFLD), have higher incidence of infections and mortality rate due to sepsis. The current focus in the development of drugs for MAFLD is the resolution of non-alcoholic steatohepatitis and prevention of progression to cirrhosis. In patients with cirrhosis or alcoholic hepatitis, sepsis is a major cause of death. As the metabolic center and a key immune tissue, liver is the guardian, modifier, and target of sepsis. Septic patients with liver dysfunction have the highest mortality rate compared with other organ dysfunctions. In addition to maintaining metabolic homeostasis, the liver produces and secretes hepatokines and acute phase proteins (APPs) essential in tissue protection, immunomodulation, and coagulation. Inflammatory liver diseases cause profound metabolic disorder and impairment of energy metabolism, liver regeneration, and production/secretion of APPs and hepatokines. Herein, the author reviews the roles of (1) disorders in the metabolism of glucose, fatty acids, ketone bodies, and amino acids as well as the clearance of ammonia and lactate in the pathogenesis of inflammatory liver diseases and sepsis; (2) cytokines/chemokines in inflammatory liver diseases and sepsis; (3) APPs and hepatokines in the protection against tissue injury and infections; and (4) major nuclear receptors/signaling pathways underlying the metabolic disorders and tissue injuries as well as the major drug targets for inflammatory liver diseases and sepsis. Approaches that focus on the liver dysfunction and regeneration will not only treat inflammatory liver diseases but also prevent the development of severe infections and sepsis.

The mitochondrial biliverdin exporter ABCB10 in hepatocytes mitigates neutrophilic inflammation in alcoholic hepatitis

Acute liver failure caused by alcoholic hepatitis (AH) is only effectively treated with liver transplantation. Livers of patients with AH show a unique molecular signature characterized by defective hepatocellular redox metabolism, concurrent to hepatic infiltration of neutrophils that express myeloperoxidase (MPO) and form neutrophil extracellular traps (NETs). Exacerbated NET formation and MPO activity contribute to liver damage in mice with AH and predicts poor prognosis in AH patients. The identification of pathways that maladaptively exacerbate neutrophilic activity in liver could inform of novel therapeutic approaches to treat AH. Whether the redox defects of hepatocytes in AH directly exacerbate neutrophilic inflammation and NET formation is unclear. Here we identify that the protein content of the mitochondrial biliverdin exporter ABCB10, which increases hepatocyte-autonomous synthesis of the ROS-scavenger bilirubin, is decreased in livers from humans and mice with AH. Increasing ABCB10 expression selectively in hepatocytes of mice with AH is sufficient to decrease MPO gene expression and histone H3 citrullination, a specific marker of NET formation. These anti-inflammatory effects can be explained by ABCB10 function reducing ROS-mediated actions in liver. Accordingly, ABCB10 gain-of-function selectively increased the mitochondrial GSH/GSSG ratio and decreased hepatic 4-HNE protein adducts, without elevating mitochondrial fat expenditure capacity, nor mitigating steatosis and hepatocyte death. Thus, our study supports that ABCB10 function regulating ROS-mediated actions within surviving hepatocytes mitigates the maladaptive activation of infiltrated neutrophils in AH. Consequently, ABCB10 gain-of-function in human hepatocytes could potentially decrease acute liver failure by decreasing the inflammatory flare caused by excessive neutrophil activity.

Hemoadsorption Therapy for Critically Ill Patients with Acute Liver Dysfunction: A Meta-Analysis and Systematic Review

Critically ill patients are at risk of developing acute liver dysfunction as part of multiorgan failure sequelae. Clearing the blood from toxic liver-related metabolites and cytokines could prevent further organ damage. Despite the increasing use of hemoadsorption for this purpose, evidence of its efficacy is lacking. Therefore, we conducted this systematic review and meta-analysis to assess the evidence on clinical outcomes following hemoadsorption therapy. A systematic search conducted in six electronic databases (PROSPERO registration: CRD42022286213) yielded 30 eligible publications between 2011 and 2023, reporting the use of hemoadsorption for a total of 335 patients presenting with liver dysfunction related to acute critical illness. Of those, 26 are case presentations (n = 84), 3 are observational studies (n = 142), and 1 is a registry analysis (n = 109). Analysis of data from individual cases showed a significant reduction in levels of aspartate transaminase (p = 0.03) and vasopressor need (p = 0.03) and a tendency to lower levels of total bilirubin, alanine transaminase, C-reactive protein, and creatinine. Pooled data showed a significant reduction in total bilirubin (mean difference of -4.79 mg/dL (95% CI: -6.25; -3.33), p = 0.002). The use of hemoadsorption for critically ill patients with acute liver dysfunction or failure seems to be safe and yields a trend towards improved liver function after therapy, but more high-quality evidence is crucially needed.

Risk factors of nosocomial infection in patients underwent artificial liver support system: a retrospective case-control study

BACKGROUND

Although nosocomial infection is one of the most discussed problems in patients undergoing artificial liver support system (ALSS) treatment, only few solutions have been proposed so far. This study aimed to explore the risk factors of nosocomial infection in patients treated with ALSS in order to aid in the development of future preventive measures.

METHODS

This retrospective case-control study included patients treated with ALSS at the Department of Infectious Diseases, First Affiliated Hospital of xxx Medical University between January 2016 and December 2021.

RESULTS

One hundred seventy-four patients were included. There were 57 patients in the nosocomial infection group and 117 patients in the non-nosocomial infection group, of them 127 males (72.99%) and 47 females (27.01%) with an average age of 48.15 ± 14.19 years old. Multivariate logistic regression analysis revealed that total bilirubin [odds ratio (OR) = 1.004; 95% confidence interval (CI), 1.001-1.007; P  = 0.020], number of invasive procedures (OR = 2.161; 95% CI, 1.500-3.313; P  < 0.001), blood transfusion (OR = 2.526; 95% CI, 1.312-4.864; P  = 0.006) were independent risk factors and haemoglobin (Hb) (OR = 0.973; 95% CI, 0.953-0.994; P  = 0.011) was a protective factor for nosocomial infection in patients treated with ALSS.

CONCLUSION

The total bilirubin, transfusion of blood products and higher number of invasive operations were independent risk factors for nosocomial infection in patients treated with ALSS, while higher Hb was a protective factor.

Evaluation of qSOFA score, and conjugated bilirubin and creatinine levels for predicting 28‑day mortality in patients with sepsis

Sepsis is a dangerous disease that develops rapidly and has a high mortality rate. A timely and accurate assessment of the patient's condition is beneficial in improving prognosis and reducing mortality. Therefore, the present study was designed to investigate the potential association between quick sequential organ failure assessment (qSOFA) scores and biochemical indicators, such as conjugated bilirubin (CB) and creatinine levels, with the 28-day prognosis of patients with sepsis in a retrospective observational study. All cases were divided into survival and non-survival groups on the 28th day after diagnosis. The qSOFA scores, and CB and creatinine levels were significantly higher in the non-survival group than in the survival group (both P<0.01). Cox regression models identified CB [hazard ratio (HR), 1.006; P=0.002] and creatinine levels (HR, 1.002; P=0.024) as independent factors affecting 28-day mortality. The area under the curve (AUC) for CB and creatinine levels plus qSOFA score was 0.792 (95% confidence interval, 0.745-0.834), which was larger than the values for CB level, creatinine level and qSOFA score alone (all P<0.01) in the prognosis of 28-day mortality. The cut-off value of CB and creatinine levels plus qSOFA score for the 28-day mortality was 0.275 (-2.466 + 0.012 x CB + 0.002 x creatinine + 1.289 x qSOFA). Patients with lower combined predictor values had a better prognosis as demonstrated by Kaplan-Meier survival curves (log-rank test, 10.060; P=0.002). In both the septic shock and sepsis groups, the combined predictor value was higher in the non-survival group than in the survival group (P<0.001). Therefore, an increase in the combined predictor value of CB and creatinine levels plus qSOFA score may be an important predictor of disease progression and prognosis in patients with sepsis and septic shock.

Dihydrolipoamide Acetyltransferase AceF Influences the Type III Secretion System and Resistance to Oxidative Stresses through RsmY/Z in Pseudomonas aeruginosa

Carbon metabolism plays an important role in bacterial physiology and pathogenesis. The type III secretion system (T3SS) of Pseudomonas aeruginosa is a virulence factor that contributes to acute infections. It has been demonstrated that bacterial metabolism affects the T3SS. Meanwhile, expression of T3SS genes is negatively regulated by the small RNAs RsmY and RsmZ. In this study, we studied the relationship between the dihydrolipoamide acetyltransferase gene aceF and the T3SS. Our results reveal an upregulation of RsmY and RsmZ in the aceF mutant, which represses the expression of the T3SS genes. Meanwhile, the aceF mutant is more tolerant to hydrogen peroxide. We demonstrate that the expression levels of the catalase KatB and the alkyl hydroperoxide reductase AhpB are increased in the aceF mutant. The simultaneous deletion of rsmY and rsmZ in the aceF mutant restored the expression levels of katB and ahpB, as well as bacterial susceptibility to hydrogen peroxide. Thus, we identify a novel role of AceF in the virulence and oxidative response of P. aeruginosa.

Lipid peroxidation functional state changes in patients with obstructive jaundice depending on the level of bilirubin in the blood

Obstructive jaundice (OJ) is the most common syndrome among diseases of the hepatopancreatoduodenal region and is found in 12-45% of cases. OJ may be benign and malignant etiology. Despite the evidence of the participation of bilirubin in reducing the bactericidal properties of neutrophils, there are no data currently on changes in the functioning of the antioxidant defense system depending on the level of bilirubin in the blood of patients with OJ of various origins. Research in this direction reveals the possibility for the development of pathogenetic recommendations for influencing these links of the pathogenesis of the disease. The study included men with OJ of non-malignant (OJNMG) (n = 47; mean age - 52.02 ± 5.18 years) and OJ of malignant genesis (OJMG) (I-II stages of the malignant process) (n = 45; mean age - 53.02 ± 4.8 years), divided into three subgroups, depending on the level of bilirubin in the blood. The indicators of practically healthy men as a control (n = 50, average age - 48.7 ± 3.9 years) were used. Spectrophotometric and statistical research methods were used. A statistically significant decrease of superoxide dismutase, glutathione-S-transferase, glutathione-peroxidase, ceruloplasmin, an increase in the values of diene conjugates, malondialdehyde in the group of patients with OJNMG relative to the control was revealed, regardless of the level of bilirubin in the blood. The presence of malignant genesis of the disease with more intense changes in the studied parameters relative to control is accompanied. Comparison of indicators between groups of patients with OJ of different genesis showed a decrease in the values of glutathione-S-transferase and an increase in the level of diene conjugates in patients with OJMG and the level of bilirubin less than 60 μmol / L, as well as an increase in the content of diene conjugates in patients with OJNMG and a level of bilirubin 60- 200 μmol / L in comparison with the corresponding groups of patients with OJNMG. Thus, both in the groups with OJNMG and in the groups with OJMG, there is a significant decrease in the activity of the main antioxidant enzymes and an increase in lipid peroxidation products, regardless of the level of bilirubin in the blood. The presence of malignant genesis is characterized by more intense differences. The revealed changes can serve as additional criteria for optimizing the diagnosis and treatment of this cohort of patients.

Heme-Oxygenase-1 Attenuates Oxidative Functions of Antigen Presenting Cells and Promotes Regulatory T Cell Differentiation during Fasciola hepatica Infection

Fasciola hepatica is a fluke that infects livestock and humans causing fasciolosis, a zoonotic disease of increasing importance due to its worldwide distribution and high economic losses. The parasite regulates the host immune system by inducing a strong Th2 and regulatory T (Treg) cell immune response through mechanisms that might involve the expression or activity of heme-oxygenase-1 (HO-1), the rate-limiting enzyme in the catabolism of free heme that also has immunoregulatory and antioxidant properties. In this paper, we show that F. hepatica-infected mice upregulate HO-1 on peritoneal antigen-presenting cells (APC), which produce decreased levels of both reactive oxygen and nitrogen species (ROS/RNS). The presence of these cells was associated with increased levels of regulatory T cells (Tregs). Blocking the IL-10 receptor (IL-10R) during parasite infection demonstrated that the presence of splenic Tregs and peritoneal APC expressing HO-1 were both dependent on IL-10 activity. Furthermore, IL-10R neutralization as well as pharmacological treatment with the HO-1 inhibitor SnPP protected mice from parasite infection and allowed peritoneal APC to produce significantly higher ROS/RNS levels than those detected in cells from infected control mice. Finally, parasite infection carried out in gp91^phox knockout mice with inactive NADPH oxidase was associated with decreased levels of peritoneal HO-1⁺ cells and splenic Tregs, and partially protected mice from the hepatic damage induced by the parasite, revealing the complexity of the molecular mechanisms involving ROS production that participate in the complex pathology induced by this helminth. Altogether, these results contribute to the elucidation of the immunoregulatory and antioxidant role of HO-1 induced by F. hepatica in the host, providing alternative checkpoints that might control fasciolosis.

The mildly decreased preoperative bilirubin level is a risk factor for periprosthetic joint infection after total hip and knee arthroplasty

BACKGROUND

Many serologic markers are routinely tested prior to joint arthroplasty, but only few are commonly used to guide surgeons in determining patients most at risk of periprosthetic joint infection (PJI). The objective of this study was to investigate the association between preoperative bilirubin level and PJI after primary hip and knee arthroplasty.

METHODS

A retrospective analysis was performed on patients undergoing revision hip and knee arthroplasty at our hospital from January 2016 to December 2019. Laboratory biomarkers were collected before the primary arthroplasty, as well as general patient information. The association between the above serologic markers and postoperative PJI was analyzed.

RESULTS

A total of 72 patients (30 hips/42 knees) were analyzed, including 39 patients with PJI and 33 patients without PJI. Except for total bilirubin (TB) and direct bilirubin (DB), there was no significant difference between the remaining laboratory biomarkers. The preoperative TB and DB in the PJI group were 10.84 ± 0.61 μmol/L and 3.07 ± 0.19 μmol/L, respectively, which were lower than those in the non-PJI group (14.68 ± 0.75 μmol/L and 4.70 ± 0.39 μmol/L, P < 0.001). The area under the curve (AUC) of preoperative TB to predict PJI was 0.755 (P < 0.001, cutoff = 11.55 μmol/L, sensitivity = 66.67%, specificity = 75.76%). Meanwhile, the AUC of preoperative DB was 0.760 (P < 0.001, cutoff = 4.00 μmol/L, sensitivity = 84.62%, specificity = 54.45%).

CONCLUSIONS

The serum levels of TB and DB before the primary arthroplasty were lower in PJI patients than in non-PJI patients, and the preoperative values lower than 11.55 μmol/L and 4.00 μmol/L could be considered as a risk factor for postoperative PJI.

The immune function of heme oxygenase-1 from grass carp (Ctenopharyngodon idellus) in response to bacterial infection

Heme oxygenase (HO)-1, a rate-limiting enzyme in heme catabolism, results in the formation of equivalent amounts of biliverdin (BV), carbon monoxide (CO) and ferrous iron (Fe²⁺). Previous studies have revealed that HO-1 plays an important role in immune responses. However, the mechanism underlying the immune responses against bacterial infection of teleost HO-1 remains enigmatic. To decipher the mechanisms, we have cloned and characterized the HO-1 gene of grass carp (designated as GcHO-1) in this research. The results showed that the open reading frame (ORF) of GcHO-1 was 819 bp, which encoded a putative protein of 272 amino acids. The deduced amino acid sequence phylogenetically shared the highest identity with other teleosts, and contained two domains of heme-oxygenase and a single-pass transmembrane domain. The mRNA expressions of GcHO-1 in healthy grass carp have widely existed in examined tissues in the following order of spleen > head-kidney > middle head-kidney > intestines > liver > gills > heart > muscle > brain. Besides, the mRNA and protein transcription of GcHO-1 were both significantly up-regulated in the liver and head-kidney tissues after Staphylococcus aureus and Aeromonas hydrophila infection. In addition, overexpression of GcHO-1 in kidney cell line (CIK) cells of grass carp could reduce the expression of inflammatory cytokines (IL-1β, IL-8, TNFα, CCL1 and IL-6). Herein, we demonstrate that GcHO-1 plays an anti-inflammatory role in innate immunity. Our results shed new light on the mechanisms underlying the antibacterial immunity of teleost.

Modulation of Inflammation and Immune Responses by Heme Oxygenase-1: Implications for Infection with Intracellular Pathogens

Heme oxygenase-1 (HO-1) catalyzes the degradation of heme molecules releasing equimolar amounts of biliverdin, iron and carbon monoxide. Its expression is induced in response to stress signals such as reactive oxygen species and inflammatory mediators with antioxidant, anti-inflammatory and immunosuppressive consequences for the host. Interestingly, several intracellular pathogens responsible for major human diseases have been shown to be powerful inducers of HO-1 expression in both host cells and in vivo. Studies have shown that this HO-1 response can be either host detrimental by impairing pathogen control or host beneficial by limiting infection induced inflammation and tissue pathology. These properties make HO-1 an attractive target for host-directed therapy (HDT) of the diseases in question, many of which have been difficult to control using conventional antibiotic approaches. Here we review the mechanisms by which HO-1 expression is induced and how the enzyme regulates inflammatory and immune responses during infection with a number of different intracellular bacterial and protozoan pathogens highlighting mechanistic commonalities and differences with the goal of identifying targets for disease intervention.

The Anti-Inflammatory Role of Bilirubin on "Two-Hit" Sepsis Animal Model

Introduction: Bilirubin is a product of the heme catabolism pathway, and it is excreted in bile and removed from the body through the urine. Bilirubin has potent antioxidant properties but also plays a role in anti-inflammation by protecting the body against endotoxin-induced lung inflammation, down-regulating the expression of adhesion molecules, and inhibiting the infiltration of inflammatory cells. Thus, bilirubin is a promising agent that could use in inflammation disease treatment. The application of bilirubin on the “two-hit” sepsis animal model has been, to date, unknown. Methods: we used lipopolysaccharide to induce initial insults in C57BL/6 mice. After 24 h, mice underwent cecal ligation and puncture to induce the “two-hit” sepsis model. Next, mice were administered 30 mg/kg bilirubin and we observed an improvement. Results: We observed that bilirubin inhibited the expression of pro-inflammatory cytokines, while the levels of anti-inflammatory cytokines were significantly augmented in the lung. Bilirubin improved the survival rate in the sepsis model. Furthermore, we suggest that bilirubin can modulate the accumulation of T-regulatory cells and myeloid-derived suppressor cells. Notably, bilirubin suppressed the activation and functions of T-cells. Conclusions: These results clarified that bilirubin might improve tissue injury in sepsis through anti-inflammatory mechanisms.

Mildly decreased preoperative bilirubin levels are associated with infections after shoulder and knee arthroplasty

Increasing numbers of arthroplasties are also accompanied by postoperative infections. The main purpose was to evaluate preoperative serum bilirubin levels between patients with and without infections after shoulder and knee arthroplasties. For this retrospective case-control single-center study, a total of 108 patients were extracted from a prospectively collected database. Eighteen patients with infections after shoulder (n = 8) and knee (n = 10) arthroplasty were matched by age, gender, and implant type in a 1:5-scenario to 90 patients (40 shoulders and 50 knees) without postoperative infection. Demographic data, preoperative blood parameters, and postoperative infection-related outcomes were evaluated. Total bilirubin was the only preoperative parameter significantly different between the infection (8.21 ± 3.25 μmol/L or 0.48 ± 0.19 mg/dL) and noninfection (10.78 ± 4.62 μmol/L or 0.63 ± 0.27 mg/dL; P = .014) group, while C-reactive protein and other liver parameters were similar between the groups. Significantly more controls (92.1%) had preoperative bilirubin levels above 8.72 μmol/L or 0.51 mg/dL than cases (7.9%; P = .007). The 5-year infection survival-rate was 65.6% for patients with preoperative bilirubin levels < 8.72 μmol/L or < 0.51 mg/dL and 91.2% with ≥ 8.72 μmol/L or ≥ 0.51 mg/dL. Mildly decreased preoperative bilirubin levels with a cutoff at 8.72 μmol/L or 0.51 mg/dL were significantly associated to patients with infections after shoulder and knee arthroplasty. There were no differences in other blood parameters or comorbidities between patients with infections and their matched-controls.

The Good and the Bad Side of Heme-Oxygenase-1 in the Gut

Significance: Mucosal immunity in the gut has the important task of protecting an organism against potential danger, but at the same time of staying silent in response to harmless antigens present in the intestinal lumen. The delicate balance between immune activation and tolerance is referred to as gut homeostasis. Recent Advances: It has become clear that different types of immune cells and several factors participate in the maintenance of gut homeostasis, having as a final goal the prevention of non-necessary inflammation. Immune cells of the myeloid lineage, such as macrophages located in the lamina propria, represent the most abundant leukocyte population in the intestine and play a critical role in keeping the immune system silent, via the production of the anti-inflammatory cytokine interleukin-10. Critical Issues: Gut macrophages are an important source of the oxidative enzyme heme-oxygenase-1 (HO-1), which has crucial immune-modulatory properties. The protective role of HO-1 in the control of the intestinal inflammation, and its connection with the enteric flora have been demonstrated in experimental settings as well as in human biological samples. Future Directions: Loss of the gut homeostasis gives rise to conditions of acute inflammation that may degenerate into chronic disease, eventually leading to carcinogenesis. Understanding the mechanisms that regulate this enzyme will disclose novel therapeutic approaches that are designed to control chronic inflammation in the intestine.

The role of bilirubin to albumin ratio as a predictor for mortality in critically ill patients without existing liver or biliary tract disease

Background:

Hyperbilirubinemia and hypoalbuminemia are frequently appeared and associated with poor prognosis in critically ill patients. We aim to evaluate the association between the bilirubin to albumin ratio and prognosis in intensive care unit (ICU) patients.

Methods:

This was a retrospective study of 731 patients who were admitted to the medical intensive care unit (MICU) at a tertiary-care center from July 2015 to September 2017. We analyzed the bilirubin to albumin ratio on admission to the MICU, including clinical characteristics and other examinations.

Results:

The overall 28-day survival of MICU patients was 69.1%. On univariate analysis, Acute Physiology and Chronic Health Evaluation (APACHE) II score (P<0.001), Sequential Organ Failure Assessment score (P<0.001), Simplified Acute Physiology Score II score (P<0.001), Creactive protein (P=0.015), and bilirubin/albumin ratio (P<0.001) were associated with mortality of ICU patients. The receiver operating characteristic curves for ICU patients mortality between bilirubin to albumin ratio and APACHE II score were not statistically significant (P=0.282). On multivariate analysis, higher APACHE II score (hazard ratio [HR], 1.05; 95% CI, 1.03 to 1.06; P<0.001) and bilirubin to albumin ratio (HR, 1.65; 95% CI, 1.23 to 2.20; P=0.001) were independently related to the ICU patient mortality.

Conclusions:

A higher bilirubin to albumin ratio was related to the unfavorable prognosis and mortality in critically ill patients.

Heme Catabolic Pathway in Inflammation and Immune Disorders

In recent years, the heme catabolic pathway is considered to play an important regulatory role in cell protection, apoptosis, inflammation, and other physiological and pathological processes. An appropriate amount of heme forms the basic elements of various life activities, while when released in large quantities, it can induce toxicity by mediating oxidative stress and inflammation. Heme oxygenase (HO) -1 can catabolize free heme into carbon monoxide (CO), ferrous iron, and biliverdin (BV)/bilirubin (BR). The diverse functions of these metabolites in immune systems are fascinating. Decades work shows that administration of degradation products of heme such as CO and BV/BR exerts protective activities in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), multiple sclerosis (MS) and other immune disorders. This review elaborates the molecular and biochemical characterization of heme catabolic pathway, discusses the signal transduction and immunomodulatory mechanism in inflammation and summarizes the promising therapeutic strategies based on this pathway in inflammatory and immune disorders.

Delayed Antibiotic Therapy and Organ Dysfunction in Critically Ill Septic Patients in the Emergency Department

Background: We investigated the effect of antibiotic timing on outcomes based on changes in surrogate markers of organ failure, including platelet, serum bilirubin, serum creatinine levels, and the PaO₂/FiO₂ (P/F) ratio. Methods: This was a single-center, retrospective observational study of critically ill septic patients who presented to the emergency department (ED). The study period extended from August 2008 to September 2016. The primary outcomes included changes in platelet, serum bilirubin, serum creatinine levels, and the P/F ratio (δ-platelet, δ-serum bilirubin, δ-serum creatinine, and δ-P/F ratio were calculated as values measured on Day 3; values measured at ED enrollment). A multivariable linear regression model was developed to assess variables related to outcomes (δ-platelet, δ-serum bilirubin, δ-serum creatinine, and δ-P/F ratio). Results: We analyzed 1784 patients who met the inclusion criteria. The overall 28-day mortality was 14% (n = 256/1784). On multivariable linear regression analysis, the hourly delay in antibiotic therapy was significantly associated with a decrease in δ-platelet count (coefficient, −1.741; standard error, 0.740; p = 0.019), and an increase in δ-serum bilirubin (coefficient, 0.054; standard error, 0.021; p = 0.009). In contrast, it was not associated with δ-creatinine (coefficient, 0.008; standard error, 0.010; p = 0.434) or the δ-P/F ratio (coefficient, −0.797; standard error, 1.858; p = 0.668). Conclusion: The hourly delay of antibiotic therapy was associated with decreased platelet count and increased serum bilirubin concentration in critically ill septic patients during the first three days of ED admission.

Bile and circulating HMGB1 contributes to systemic inflammation in obstructive jaundice

BACKGROUND

Obstructive jaundice (OJ) patients with cholangitis are prone to sepsis; however, the underlying mechanisms are still not clear and need to be clarified.

METHODS

Analyzing all available published data related to the title of this article.

RESULTS

OJ leads to absence of gut luminal bile and accumulation of hepatic and circulating bile acids. Absence of gut luminal bile deprives the gut from its antiinflammatory, endotoxin-binding, bacteriostatic, mucosal-trophic, epithelial tight-junction maintaining, and gut motility-regulating effects, leading to gut bacterial overgrowth, mucosal atrophy, mucosal tight-junction loss, and gut motility dysfunction. These alterations promote intestinal endotoxin and bacterial translocation (BT) into portal and systemic circulation. Gut BT triggers systemic inflammation, which can lead to multiple organ dysfunctions in OJ. The accumulation of hepatic and circulating bile acids kills/damages hepatocyte and Kupffer cells, and it also significantly decreases the number of liver natural killer T-cells in OJ. This results in impaired hepatic and systemic immune function, which facilitates BT. In addition, neutralizing bile HMGB1 can reverse endotoxemic bile-induced gut BT and mucosal injury in mice, suggesting that bile HMGB1 in OJ patients can be responsible for internal drainage-related clinical complications. Moreover, the elevated circulating HMGB1 level may contribute to multiple organ injuries, and it might also mediate gut BT in OJ.

CONCLUSIONS

HMGB1 may significantly contribute to systemic inflammation and multiple organ dysfunctions in OJ.

The macrophage heme-heme oxygenase-1 system and its role in inflammation

Heme oxygenase (HO)-1, the inducible isoform of the heme-degrading enzyme HO, plays a critical role in inflammation and iron homeostasis. Regulatory functions of HO-1 are mediated via the catalytic breakdown of heme, which is an iron-containing tetrapyrrole complex with potential pro-oxidant and pro-inflammatory effects. In addition, the HO reaction produces the antioxidant and anti-inflammatory compounds carbon monoxide (CO) and biliverdin, subsequently converted into bilirubin, along with iron, which is reutilized for erythropoiesis. HO-1 is up-regulated by a plethora of stimuli and injuries in most cell types and tissues and provides salutary effects by restoring physiological homeostasis. Notably, HO-1 exhibits critical immuno-modulatory functions in macrophages, which are a major cell population of the mononuclear phagocyte system. Macrophages play key roles as sentinels and regulators of the immune system and HO-1 in these cells appears to be of critical importance for driving resolution of inflammatory responses. In this review, the complex functions and regulatory mechanisms of HO-1 in macrophages will be high-lighted. A particular focus will be the intricate interactions of HO-1 with its substrate heme, which play a contradictory role in distinct physiological and pathophysiological settings. The therapeutic potential of targeted modulation of the macrophage heme-HO-1 system will be discussed in the context of inflammatory disorders.

Increased mortality in critically ill patients with mild or moderate hyperbilirubinemia

PURPOSE

Increased bilirubin concentrations may be related to outcome, but this has not been well studied. We evaluated the relationship between total serum bilirubin levels and outcome in critically ill patients.

MATERIALS AND METHODS

Data were analyzed from adult critically ill patients included in a 1-day international prevalence study after excluding those with an obvious underlying cause of hyperbilirubinemia.

RESULTS

Serum bilirubin concentrations were >1 mg/dL in 2803 (31%) of 8973 patients, and these patients had higher mortality rates than patients with lower bilirubin concentrations (30% vs 21%, P<.01). For serum bilirubin values of 1.1-6 mg/dL, there was a linear increase in crude mortality (R²=0.96), with the highest hospital mortality (42%) in patients with bilirubin concentrations between 3.7 and 6.0 mg/dL. There was no further increase in the mortality rates for patients with bilirubin concentrations >6 mg/dL. A serum bilirubin concentration >1 mg/dL was an independent risk factor for mortality in multilevel analysis.

CONCLUSIONS

Hyperbilirubinemia without a recognized cause was common and independently associated with increased mortality. There was a linear correlation of mortality with bilirubin concentration for values between 1 and 6 mg/dL but not for higher values.

Pseudomonas aeruginosa Enolase Influences Bacterial Tolerance to Oxidative Stresses and Virulence

Pseudomonas aeruginosa is a Gram negative opportunistic pathogenic bacterium, which causes acute and chronic infections. Upon entering the host, bacteria alter global gene expression to adapt to host environment and avoid clearance by the host. Enolase is a glycolytic enzyme involved in carbon metabolism. It is also a component of RNA degradosome, which is involved in RNA processing and gene regulation. Here, we report that enolase is required for the virulence of P. aeruginosa in a murine acute pneumonia model. Mutation of enolase coding gene (eno) increased bacterial susceptibility to neutrophil mediated killing, which is due to reduced tolerance to oxidative stress. Catalases and alkyl hydroperoxide reductases play a major role in protecting the cell from oxidative damages. In the eno mutant, the expression levels of catalases (KatA and KatB) were similar as those in the wild type strain in the presence of H₂O₂, however, the expression levels of alkyl hydroperoxide reductases (AhpB and AhpC) were significantly reduced. Overexpression of ahpB but not ahpC in the eno mutant fully restored the bacterial resistance to H₂O₂ as well as neutrophil mediated killing, and partially restored bacterial virulence in the murine acute pneumonia model. Therefore, we have identified a novel role of enolase in the virulence of P. aeruginosa.

Unconjugated hyperbilirubinemia in patients with non-alcoholic fatty liver disease: a favorable endogenous response

The clinical significance of increased frequency of unconjugated hyperbilirubinemia in patients with non-alcoholic fatty liver disease (NAFLD) is unknown. Serum bilirubin is an endogenous anti-oxidant, and oxidative stress plays an important role in the pathogenesis of NAFLD. In this study, we have documented 25.4% prevalence of unconjugated hyperbilirubinemia in 204 consecutive NAFLD patients. These patients had a significantly less severe liver disease on histopathology and/or fibroScan which may be attributed to anti-oxidant effect of bilirubin.

CLP-induced impairment of innate immune function is caused by exposure to the cecal lumenal contents and not the tissue trauma or tissue ischemia/necrosis components

When mice are subjected to a Pseudomonas aeruginosa challenge 5 days after cecal ligation and puncture (CLP), clearance of the Pseudomonas is diminished when compared to sham mice. The object of this study was to determine which component(s) of CLP contributed to the impairment of the innate immune response. Mice subjected to either trauma alone or cecal ischemia/necrosis alone did not have impaired ability to clear a subsequent Pseudomonas challenge (determined by colony-forming units (cfu's) after culture of spleen tissue). However, mice subjected to abdominal contamination with heat-killed cecal contents had reduced ability to clear the subsequent Pseudomonas challenge. In contrast to normobiotic mice, neither CLP performed in germ-free mice nor abdominal contamination of mice with cecal contents from germ-free mice adversely affected clearance of a subsequent Pseudomonas challenge. These data suggest that suppressed immune function after CLP is due to exposure to microbial ligands within the cecal lumen rather than tissue trauma, ischemia, or necrosis. However, suppression of immune function did not appear to be due to exposure to LPS as TLR4-deficient mice subject to abdominal contamination with cecal contents had diminished clearance of a Pseudomonas challenge similar to that seen in wild-type mice.

High Total Bilirubin as a Protective Factor for Diabetes Mellitus: An Analysis of NHANES Data From 1999 - 2006

Background

Diabetes Mellitus (DM) is a rampantly growing epidemic in the United States, affecting nearly 10% of the adult population. Studies have shown that higher levels of Total Bilirubin (TBili) convey a protective effect with regard to cardiovascular risk. In this study, we will examine the relationship between TBili level and prevalence of DM to discern whether a similar relationship exists.

Methods

The National Health and Nutrition Examination Survey (NHANES) is a comprehensive survey performed regularly to evaluate the overall health and nutrition status of the United States population. For the purpose of this study, we combined NHANES data collected between 1999 and 2006. Totally 15,876 eligible participants were selected after excluding all patients younger than twenty years, those with a history of abnormal liver function tests, or those who disclosed a history of liver disease. The data collected on these individuals was adjusted for demographic characteristics, as well as risk factors for DM, and was analyzed via multivariate logistic regression, using SAS proc survey methodology.

Results

After age adjustment, increased TBili was associated with 26% reduction in diabetes risk (OR 0.74, 95% CI 0.64 - 0.88). Multivariate analysis, adjusting for all diabetes risk factors assessed, confirmed this association (OR 0.80, 95% CI 0.67 - 0.95).

Conclusions

Our results show that a higher level of serum TBili is associated with odds of having a lower incidence of DM. This finding supports the hypothesis that the antioxidant nature of TBili, demonstrating a protective effect with regard to the risk of stroke, atherosclerosis, and vasculitis in prior research, also extends to DM risk. Furthermore, research has shown that higher levels of TBili increase glucose mobilization into the cells, leading to more efficient, biologic glucose utilization. There is no doubt that the beneficial effect of TBili is multifactorial; thus further investigation is warranted.

Keywords

Bilirubin; Diabetes; Antioxidant; Protective

Neonatal liver failure: aetiologies and management--state of the art

Acute liver failure in neonates is rare, but carries a high mortality. Neonatal liver failure can be defined as "failure of the synthetic function of liver within 4 weeks of birth". Encephalopathy is not essential for the diagnosis. Acute liver failure in neonates differs from children with regard to aetiology and outcome. Common causes of neonatal liver failure are neonatal hemochromatosis, haematological malignancies, viral infections and liver-based metabolic defects. Early diagnosis and referral to a paediatric liver centre is recommended as liver transplantation is the only definitive treatment when supportive or a disease-specific treatment fails.

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.

Pathophysiology of increased intestinal permeability in obstructive jaundice

Despite advances in preoperative evaluation and postoperative care, intervention, especially surgery, for relief of obstructive jaundice still carries high morbidity and mortality rates, mainly due to sepsis and renal dysfunction. The key event in the pathophysiology of obstructive jaundice-associated complications is endotoxemia of gut origin because of intestinal barrier failure. This breakage of the gut barrier in obstructive jaundice is multi-factorial, involving disruption of the immunologic, biological and mechanical barrier. Experimental and clinical studies have shown that obstructive jaundice results in increased intestinal permeability. The mechanisms implicated in this phenomenon remain unresolved, but growing research interest during the last decade has shed light in our knowledge in the field. This review summarizes the current concepts in the pathophysiology of obstructive jaundice-induced gut barrier dysfunction, analyzing pivotal factors, such as altered intestinal tight junctions expression, oxidative stress and imbalance of enterocyte proliferation and apoptosis. Clinicians handling patients with obstructive jaundice should not neglect protecting the intestinal barrier function before, during and after intervention for the relief of this condition, which may improve their patients' outcome.

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.

Pathophysiology of increased intestinal permeability in obstructive jaundice

Despite advances in preoperative evaluation and postoperative care, intervention, especially surgery, for relief of obstructive jaundice still carries high morbidity and mortality rates, mainly due to sepsis and renal dysfunction. The key event in the pathophysiology of obstructive jaundice-associated complications is endotoxemia of gut origin because of intestinal barrier failure. This breakage of the gut barrier in obstructive jaundice is multi-factorial, involving disruption of the immunologic, biological and mechanical barrier. Experimental and clinical studies have shown that obstructive jaundice results in increased intestinal permeability. The mechanisms implicated in this phenomenon remain unresolved, but growing research interest during the last decade has shed light in our knowledge in the field. This review summarizes the current concepts in the pathophysiology of obstructive jaundice-induced gut barrier dysfunction, analyzing pivotal factors, such as altered intestinal tight junctions expression, oxidative stress and imbalance of enterocyte proliferation and apoptosis. Clinicians handling patients with obstructive jaundice should not neglect protecting the intestinal barrier function before, during and after intervention for the relief of this condition, which may improve their patients’ outcome.

''Iatrogenic Gilbert syndrome''--a strategy for reducing vascular and cancer risk by increasing plasma unconjugated bilirubin

The catabolism of heme, generating biliverdin, carbon monoxide, and free iron, is mediated by heme oxygenase (HO). One form of this of this enzyme, heme oxygenase-1, is inducible by numerous agents which promote oxidative stress, and is now known to provide important antioxidant protection, as demonstrated in many rodent models of free radical-mediated pathogenesis, and suggested by epidemiology observing favorable health outcomes in individuals carrying high-expression alleles of the HO-1 gene. The antioxidant impact of HO-1 appears to be mediated by bilirubin, generated rapidly from biliverdin by ubiquitously expressed biliverdin reductase. Bilirubin efficiently scavenges a wide range of physiological oxidants by electron donation. In the process, it is often reconverted to biliverdin, but biliverdin reductase quickly regenerates bilirubin, thereby greatly boosting its antioxidant potential. There is also suggestive evidence that bilirubin inhibits the activity or activation of NADPH oxidase. Increased serum bilirubin is associated with reduced risk for atherogenic disease in epidemiological studies, and more limited data show an inverse correlation between serum bilirubin and cancer risk. Gilbert syndrome, a genetic variant characterized by moderate hyperbilirubinemia attributable to reduced hepatic expression of the UDP-glucuronosyltransferase which conjugates bilirubin, has been associated with a greatly reduced risk for ischemic heart disease and hypertension in a recent study. Feasible strategies for boosting serum bilirubin levels may include administration of HO-1 inducers, supplementation with bilirubin or biliverdin, and administration of drugs which decrease the efficiency of hepatic bilirubin conjugation. The well-tolerated uricosuric drug probenecid achieves non-competitive inhibition of hepatic glucuronidation reactions by inhibiting the transport of UDP-glucuronic acid into endoplasmic reticulum; probenecid therapy is included in the differential diagnosis of hyperbilirubinemia, and presumably could be used to induce an ''iatrogenic Gilbert syndrome''. Other drugs, such as rifampin, can raise serum bilirubin through competitive inhibition of hepatocyte bilirubin uptake--although unfortunately rifampin is not as safe as probenecid. Measures which can safely achieve moderate serum elevations of bilirubin may prove to have value in the prevention and/or treatment of a wide range of disorders in which oxidants play a prominent pathogenic role, including many vascular diseases, cancer, and inflammatory syndromes. Phycobilins, algal biliverdin metabolites that are good substrates for biliverdin reductase, may prove to have clinical antioxidant potential comparable to that of bilirubin.

Incidence and prognosis of early hepatic dysfunction in critically ill patients--a prospective multicenter study

OBJECTIVE

In critically ill patients, hepatic dysfunction is regarded as a late organ failure associated with poor prognosis. We investigated the incidence and prognostic implications of early hepatic dysfunction (serum bilirubin >2 mg/dL within 48 hrs of admission).

DESIGN

Prospective, multicenter cohort study.

SETTING

Thirty-two medical, surgical, and mixed intensive care units.

PATIENTS

A total of 38,036 adult patients admitted consecutively over a period of 4 yrs.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Excluding patients with preexisting cirrhosis (n = 691; 1.8%) and acute or acute-on-chronic hepatic failure (n = 108, 0.3%), we identified 4,146 patients (10.9%) with early hepatic dysfunction. These patients had different baseline characteristics, longer median intensive care unit stays (5 vs. 3 days; p < .001) and increased hospital mortality (30.4% vs. 16.4%; p < .001). Hepatic dysfunction was also associated with higher observed-to-expected mortality ratios (1.02 vs. 0.91; p < .001). Multiple logistic regression analysis showed an independent mortality risk of hepatic dysfunction (odds ratio, 1.86; 95% confidence interval, 1.71-2.03; p < .001), which exceeded the impact of all other organ dysfunctions. A case-control study further confirmed these results: Patients with early hepatic dysfunction exhibited significantly increased raw and risk-adjusted mortality compared with control subjects.

CONCLUSIONS

Our results provide strong evidence that early hepatic dysfunction, occurring in 11% of critically ill patients, presents a specific and independent risk factor for poor prognosis.

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.

Free oxygen radicals reduce bile flow in rats via an intracellular cyclic AMP-dependent mechanism

BACKGROUND AND AIM

Oxidative stress reduces hepatic bile formation. Cyclic adenosine monophosphate (cAMP) is important in bile production; however, the role of basal amounts of intracellular cAMP in bile formation is not known. The aim of this study was to determine whether oxygen radicals reduce bile flow by mechanisms involving intrahepatocyte cAMP levels.

METHODS

The effect of an oxygen radical (tert-butyl hydroperoxide; t-BHP) on hepatic bile flow was determined in Wistar rats in vivo and in isolated perfused liver. Intracellular cAMP was measured in isolated hepatocytes with and without t-BHP in culture medium, while adenylate cyclase activity was measured in purified plasma membranes. To examine whether intracellular cAMP restoration could reverse t-BHP-induced bile flow reduction, dibutyryl cAMP (DBcAMP), a cell-membrane permeating cAMP, was used to treat isolated liver perfused with t-BHP.

RESULTS

Bile flow was significantly reduced 10 min following t-BHP administration in vivo and in isolated perfused liver (control vs 0.1 mg/mL t-BHP in perfusate, 29.3 vs 23.1 microg/kg per min, P < 0.05). Intracellular cAMP in isolated hepatocytes was reduced by adding t-BHP to the medium; this change was inhibited by DBcAMP. Adenylate cyclase activity in purified liver membrane fractions also was reduced by t-BHP. Administration of DBcAMP reversed bile flow reduction by t-BHP in isolated perfused liver.

CONCLUSIONS

Bile flow reduction by oxygen radicals was at least partly explained by inactivation of adenylate cyclase causing decreases in intrahepatocytic cAMP. Exogenous DBcAMP administration restored intracellular cAMP preventing bile flow reduction after exposure to oxygen radicals.

Impaired expression of hepatic multidrug resistance protein 2 is associated with posthepatectomy hyperbilirubinemia in patients with biliary cancer

BACKGROUND AND AIMS

Hyperbilirubinemia is a critical complication following hepatectomy for biliary cancer. Hepatic multidrug resistance protein 2 (MRP2), a bilirubin transporter, is shown to be down-regulated by acute biliary obstruction in rats. However, little is known about the effect of chronic obstruction by malignancy on the MRP2 expression in patients or the association of MRP2 expression with posthepatectomy hyperbilirubinemia.

MATERIALS AND METHODS

The MRP2 expression before hepatectomy was determined by immunostaining and Western blotting in patients with biliary cancer. To directly determine the effect of chronic bile duct obstruction on the MRP2 expression, the expression levels were compared between the cholestatic and noncholestatic lobes in each of seven patients. In another 39 patients, the correlation of the MRP2 expression of the anticipated remnant liver with the posthepatectomy severe hyperbilirubinemia, defined as a serum total bilirubin concentration>or=200 micromol/l, was evaluated.

RESULTS

The MRP2 staining in the cholestatic lobes was weak and not restricted to the canalicular membrane, unlike the noncholestatic lobes. The expression levels in the cholestatic lobes were 45% of those in the noncholestatic lobes. Postoperative maximum bilirubin levels were significantly correlated with MRP2 expression of the anticipated remnant liver. The MRP2 expression had been already impaired before hepatectomy in all patients who eventually developed severe hyperbilirubinemia.

CONCLUSIONS

Decreased MRP2 expression, caused by biliary obstruction due to cancer, is a possible risk factor for posthepatectomy severe hyperbilirubinemia.

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

Extrahepatic cholestasis often evokes liver injury with hepatocyte apoptosis, aberrant cytokine production, and-most importantly-postoperative septic complications. To clarify the involvement of aberrant cytokine production and hepatocyte apoptosis in impaired resistance to bacterial infection in obstructive cholestasis, C57BL/6 mice or Fas-mutated lpr mice were inoculated intraperitoneally with 10(7) colony-forming units of Escherichia coli 5 days after bile duct ligation (BDL) or sham celiotomy. Cytokine levels in sera, liver, and immune cells were assessed via enzyme-linked immunosorbent assay or real-time reverse-transcriptase polymerase chain reaction. BDL mice showed delayed clearance of E. coli in peritoneal cavity, liver, and spleen. Significantly higher levels of serum interleukin (IL) 10 with lower levels of IL-12p40 were observed in BDL mice following E. coli infection. Interferon gamma production from liver lymphocytes in BDL mice was not increased after E. coli infection either at the transcriptional or protein level. Kupffer cells from BDL mice produced low levels of IL-12p40 and high levels of IL-10 in vitro in response to lipopolysaccharide derived from E. coli. In vivo administration of anti-IL-10 monoclonal antibody ameliorated the course of E. coli infection in BDL mice. Furthermore, BDL-lpr mice did not exhibit impairment in E. coli killing in association with little hepatic injury and a small amount of IL-10 production. In conclusion, increased IL-10 and reciprocally suppressed IL-12 production by Kupffer cells are responsible for deteriorated resistance to bacterial infection in BDL mice. Fas-mediated hepatocyte apoptosis in cholestasis may be involved in the predominant IL-10 production by Kupffer cells.

MARS therapy in critically ill patients with advanced malignancy: a clinical and technical report

BACKGROUND/METHODS

Molecular Adsorbent Recirculating System (MARS) was used in three consecutive critically ill patients at the Singapore General Hospital with advanced malignancy and acute liver failure (ALF). Case 1 was a male patient with hepatocellular carcinoma (HCC) for which initial right hepatectomy was followed by left hepatectomy 5 months later for recurrent HCC. The postoperative course following second surgery was complicated by severe methicillin-resistant Staphylococcus aureus (MRSA) sepsis, mild azotaemia and subacute cholestatic liver failure. MARS was used thrice in this patient. Case 2 was a female patient with advanced acute lymphoblastic leukaemia (ALL) with post bone marrow transplantation (BMT) acute haemolytic-uraemic syndrome (HUS) secondary to cyclosporin A (Cy A), cytomegalovirus (CMV) infection, severe nosocomial pneumonia, acute renal failure (ARF) treated with continuous haemofiltration and acute veno-occlusive disease resulting in Budd-Chiari syndrome. The latter precipitated ALF. MARS was instituted twice. Case 3 was a male patient with advanced, refractory Hodgkin's disease previously treated with multiple courses of chemotherapy. ALF developed secondary to acute viral hepatitis B flare. He was given a trial of MARS once in the ICU. All the three patients eventually died.

RESULTS

Mean MARS intradialytic systemic pressures were as follows: systolic pressure range was 95 +/- 17 to 128 +/- 17 mmHg and diastolic pressure range was 51 +/- 5 to 67 +/- 7 mmHg. Pressure at albumin dialysate exit point from dialyser 1 (Ae) ranged from 253 +/- 11 to 339 +/- 15 mmHg and that at albumin dialysate entry point into dialyser 1 (Aa) ranged from 142 +/- 11 to 210 +/- 6 mmHg. Ultrafiltration (UF) was 633 +/- 622 mL over mean treatment duration of 6.3 +/- 0.9 h with a total heparin dose of 1583 +/- 817 IU. Coagulation status pre- and 6-h post-MARS was similar: aPTT (P=0.116) and platelet count (P=0.753). There were no bleeding complications or circuit thromboses. MARS had a significant de-uraemization effect (pre- and post-MARS serum creatinine and urea: P=0.046 and 0.028, respectively) but did not significantly attenuate blood lactate, ammonia or total bilirubin levels. Albumin dialysate (Ae - Aa) urea and creatinine concentrations appeared to be sharply attenuated after 6 h of MARS. In contrast, the removal of total bilirubin by albumin dialysate from the blood compartment appeared to plateau after 4 h of continuous MARS operation.

CONCLUSIONS

MARS was well-tolerated in critically ill patients with advanced and complicated cancer. Low-dose heparin was safe and did not compromise MARS circuit integrity. Although MARS had a significant de-uraemization effect, this appeared to be limited by the duration of MARS operation. Our data suggested that such a limit was reached earlier for total bilirubin. More data are needed to confirm the present findings and further delineate the saturation limit of MARS for different toxins that accumulate in ALF. This would affect the optimal duration of MARS therapy.

Oxidant and antioxidant activities in childhood meningitis

Animal studies have provided substantial evidence for a key role of reactive oxygen species, nitric oxide and its related compounds in the complex pathophysiology of bacterial meningitis. However, there is little information on changes in the redox status in human meningitis. In the present study, we evaluated the redox status and oxidative stress in the central nervous system of children with meningitis. Oxidant and antioxidant activities were assessed from cerebrospinal fluid levels of acrolein-lysine adducts (a marker of lipid peroxidation), nitrite (a marker of nitric oxide production) and bilirubin derivatives (a marker of antioxidant activity of bilirubin). All these markers were several times higher in children during the early phase of bacterial meningitis compared with those of children without meningitis and patients with aseptic meningitis. In the bacterial meningitis group, the levels of bilirubin derivatives correlated significantly with those of acrolein-lysine adducts and nitrite. Acrolein-lysine adducts and nitrite decreased significantly as the patients started to respond to treatment but bilirubin derivatives remained elevated. In conclusion, our data indicate the enhancement of both oxidant and antioxidant activities in the central nervous system of children with early bacterial meningitis, but not in those with aseptic meningitis. Clinical and laboratory improvement may be associated with a decrease in oxidant activities in the central nervous system.