Liver histology in ICU patients dying from sepsis: A clinico-pathological study

Fetuin A is a Predictor of Liver Fat in Preoperative Patients with Nonalcoholic Fatty Liver Disease

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD) and steatohepatitis (NASH) are frequent comorbidities in perioperative patients. However, the predictive role of the hepatokine fetuin A was not evaluated in this collective.

OBJECTIVE

To study fetuin A as predictor of NAFLD/NASH in preoperative patients.

METHODS

58 subjects were included. Fetuin A was studied in patients undergoing open abdominal surgery and in a subset with acute liver failure. Blood and liver specimens were sampled. NAFLD was histologically evaluated. Liver fat was additionally analyzed by an enzymatic approach, circulating fetuin A by enzyme linked-immunosorbent assay, fetuin A mRNA by reverse-transcription PCR.

RESULTS

Univariate correlation studies linked fetuin A to liver steatosis (r = 0.40, p = .029) and hepatocellular ballooning degeneration (r = 0.34, p = .026). Compared to non-NAFLD subjects fetuin A was increased in NAFLD (p = .009) and in NASH (p = .029). However, when corrected for main confounders by linear modeling, fetuin A remained related to hepatic steatosis, but not to ballooning degeneration or other NAFLD features. In support of this, biochemically analyzed liver lipids correlated with fetuin A in plasma (r = 0.34, p = .033) and with hepatic fetuin A mRNA (r = 0.54, p < .001). In addition, plasma fetuin A was related to hepatic mRNA (r = 0.32, p = .036), while circulating levels were reduced by 64% with acute liver failure (p < .001), confirming the liver as main fetuin A source.

CONCLUSION

Fetuin A is suggested as noninvasive biomarker of hepatic steatosis in preoperative settings.

Liver function predicts survival in patients undergoing extracorporeal membrane oxygenation following cardiovascular surgery

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) represents a valuable and rapidly evolving therapeutic option in patients with severe heart or lung failure following cardiovascular surgery. However, despite significant advances in ECMO techniques and management, prognosis remains poor and accurate risk stratification challenging. We therefore evaluated the predictive value of liver function variables on all-cause mortality in patients undergoing venoarterial ECMO support after cardiovascular surgery.

METHODS

We included into our single-center registry a total of 240 patients undergoing venoarterial ECMO therapy following cardiovascular surgery at a university-affiliated tertiary care center.

RESULTS

The median follow-up was 37 months (interquartile range 19-67 months), and a total of 156 patients (65%) died. Alkaline phosphatase and total bilirubin were the strongest predictors for 30-day mortality, with adjusted hazard ratios (HRs) per 1-standard deviation increase of 1.36 (95% confidence interval [CI] 1.10-1.68; P = 0.004) and 1.22 (95% CI 1.07-1.40; P = 0.004), respectively. The observed associations persisted for long-term mortality, with adjusted HRs of 1.27 (95% CI 1.03-1.56; P = 0.023) for alkaline phosphatase and 1.22 (95% CI 1.07-1.39; P = 0.003) for total bilirubin.

CONCLUSIONS

The present study demonstrates that elevated values of alkaline phosphatase and total bilirubin are sensitive parameters for predicting the short-term and long-term outcomes of ECMO patients.

Hepatosplanchnic circulation in cirrhosis and sepsis

Hepatosplanchnic circulation receives almost half of cardiac output and is essential to physiologic homeostasis. Liver cirrhosis is estimated to affect up to 1% of populations worldwide, including 1.5% to 3.3% of intensive care unit patients. Cirrhosis leads to hepatosplanchnic circulatory abnormalities and end-organ damage. Sepsis and cirrhosis result in similar circulatory changes and resultant multi-organ dysfunction. This review provides an overview of the hepatosplanchnic circulation in the healthy state and in cirrhosis, examines the signaling pathways that may play a role in the physiology of cirrhosis, discusses the physiology common to cirrhosis and sepsis, and reviews important issues in management.

Biomarkers in Hepatic Disease: A Review Focused on Critically Ill Patients

The ability to make a diagnosis early and appropriately is paramount for the survival of the critically ill ICU patient. Along with the myriad physical examination and imaging modalities available, biomarkers provide a window on the disease process. Herein we review hepatic biomarkers in the context of the critical care patient.

The role of the liver in sepsis

Despite the progress made in the clinical management of sepsis, sepsis morbidity and mortality rates remain high. The inflammatory pathogenesis and organ injury leading to death from sepsis are not fully understood for vital organs, especially the liver. Only recently has the role of the liver in sepsis begun to be revealed. Pre-existing liver dysfunction is a risk factor for the progression of infection to sepsis. Liver dysfunction after sepsis is an independent risk factor for multiple organ dysfunction and sepsis-induced death. The liver works as a lymphoid organ in response to sepsis. Acting as a double-edged sword in sepsis, the liver-mediated immune response is responsible for clearing bacteria and toxins but also causes inflammation, immunosuppression, and organ damage. Attenuating liver injury and restoring liver function lowers morbidity and mortality rates in patients with sepsis. This review summarizes the central role of liver in the host immune response to sepsis and in clinical outcomes.

PD-L1 blockade attenuated sepsis-induced liver injury in a mouse cecal ligation and puncture model

Liver plays a major role in hypermetabolism and produces acute phase proteins during systemic inflammatory response syndrome and it is of vital importance in host defense and bacteria clearance. Our previous studies indicated that programmed death-1 (PD-1) and its ligand programmed death ligand-1 (PD-L1) are crucial modulators of host immune responses during sepsis. Our current study was designed to investigate the role of PD-L1 in sepsis-induced liver injury by a mouse cecal ligation and puncture (CLP) model. Our results indicated that there was a significant increase of PD-L1 expression in liver after CLP challenge compared to sham-operated controls, in terms of levels of mRNA transcription and immunohistochemistry. Anti-PD-L1 antibody significantly alleviated the morphology of liver injury in CLP mice. Anti-PD-L1 antibody administration decreased ALT and AST release in CLP mice, decreased the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-10 mRNA in liver after sepsis challenge. Thus, anti-PD-L1 antibody might have a therapeutic potential in attenuating liver injury in sepsis.

Hepatotoxicity of antibiotics: a review and update for the clinician

Collectively, the various classes of antibiotics are a leading cause of drug-induced liver injury (DILI). However, acute antibiotic-associated DILI can be difficult to diagnose, as the course of therapy is usually brief, and other confounding factors are often present. In addition to the broad clinicopathologic spectrum of hepatotoxicity associated with the antimicrobials, the underlying infectious disease being treated may itself be associated with hepatic dysfunction and jaundice. This review provides summarized information on several classes of antimicrobial agents, highlighting new agents causing DILI and updating information on older agents.

Comparison of the effects of different intravenous fat emulsions in patients with systemic inflammatory response syndrome and sepsis

BACKGROUND

In this study, the authors aimed to compare the effects that a medium- and long-chain triglyceride (MCT/LCT) fat infusion and a fish oil-based (ω-3) fat infusion for parenteral nutrition (PN) had on systemic inflammation, cytokine response, and hepatic steatosis in mixed intensive care unit (ICU) patients.

METHODS

This was a single-center, placebo-controlled, randomized clinical trial in a university hospital. Four patient groups, including systemic inflammatory response syndrome (SIRS) and sepsis patients, were assigned to receive PN employing the MCT/LCT fat infusion or the fish oil-based fat infusion over 7 days. Blood biochemistry and liver steatosis were evaluated.

RESULTS

Twenty sepsis and 20 SIRS patients were included in this study. There was no statistically significant difference in terms of biochemical values and Acute Physiology and Chronic Health Evaluation II scores between the different feeding groups. Sepsis groups who received MCT/LCT revealed higher grades of liver steatosis by ultrasound on days 7 and 10 (P < .05). Tumor necrosis factor (TNF)-α and interleukin (IL)-6 values in sepsis group 1 (S1) were higher than in sepsis group (S2) on day 7, whereas IL-1 values were higher on days 3, 7, and 10 in group S1 than in group S2. Conversely, IL-10 values on days 3 and 7 were significantly higher in group S2.

CONCLUSION

Fish oil-based fat emulsions might have anti-inflammatory and hepatoprotective effects in hyperinflammatory disease such as sepsis.

Combination of imipenem and TAK-242, a Toll-like receptor 4 signal transduction inhibitor, improves survival in a murine model of polymicrobial sepsis

Sepsis is characterized by an excessive host response to infection. Toll-like receptors (TLRs) are essential for triggering this type of host immune response. Toll-like receptor 4 mediates recognition of LPS from gram-negative bacteria and is an important initiator of sepsis. In the present study, we evaluated the efficacy of TAK-242, a novel TLR4 signal transduction inhibitor, in a murine cecal ligation and puncture (CLP) model. Treatment with TAK-242 (10 mg/kg i.v.) in combination with imipenem (1 mg/kg s.c.) 1 h after CLP significantly increased the survival rates of mice from 17% to 50% (P ≤ 0.01) and suppressed CLP-induced increases in serum levels of IL-1[beta], IL-6, IL-10, and macrophage inflammatory protein 2 by 64%, 73%, 79%, and 81%, respectively (P ≤ 0.025). Additionally, coadministration of TAK-242 with imipenem after CLP significantly inhibited CLP-induced decreases in blood platelet counts by 37% (P ≤ 0.025) and increases in serum levels of alanine aminotransferase by 32% (P ≤ 0.025) and blood urea nitrogen by 43% (P ≤ 0.025). TAK-242 at a dose of 10 mg/kg had no effect on bacterial counts in blood, suggesting that it does not affect blood bacteria spread. These results indicate that TAK-242 shows therapeutic effects in murine polymicrobial sepsis, and it may be a potential therapeutic agent for the treatment of sepsis.

Thioredoxin binding protein-2 mediates metabolic adaptation in response to lipopolysaccharide in vivo

OBJECTIVES

Endotoxin triggers a reorganization of the energy metabolic pathway, including the promotion of fatty acid utilization to adapt to a high energy demand during endotoxemia. However, the factors responsible for the metabolic adaptation and characteristic pathologies resulting from defective utilization fatty acids during endotoxin response have not been fully clarified. The thioredoxin binding protein-2 (TBP-2) knockout (TBP-2) mouse is an animal model of fatty acid oxidation disorder. The aim of this study was to determine whether and how TBP-2 is involved in metabolic regulation in a lipopolysaccharide (LPS)-induced endotoxemia model in mice.

DESIGN

Prospective animal trial.

SETTING

Research laboratory.

SUBJECTS

TBP-2 and wild control mice.

INTERVENTION

TBP-2 and wild control mice were intraperitoneally injected with LPS. Mortality, serum levels of markers of hepatorenal injuries, cytokines, insulin, glucose and lipid derivatives, and the hepatic signaling pathway regulating gluconeogenesis were investigated.

MEASUREMENTS AND MAIN RESULTS

Following the administration of LPS, TBP-2 mice showed a predisposition for death without any significant elevation of inflammatory cytokines, compared to the wild mice. LPS-challenged TBP-2 mice showed fat deposition in the liver and kidney, organ injuries, glycogen depletion, and elevation of serum lipid derivatives such as free fatty acids, triglyceride and cholesterol. Hyperinsulinemia and hypoglycemia were observed in TBP-2 mice after LPS injection. Death due to the LPS administration was prevented by supplementation of glucose. Phosphorylation of Akt and FoxO1, an inhibitory pathway of gluconeogenesis in the liver of LPS-challenged TBP-2 mice was demonstrated, suggesting the enhancement of insulin signaling.

CONCLUSIONS

TBP-2 is involved in metabolic control during LPS-induced endotoxemia. After the LPS challenge, TBP-2 mice showed several characteristic aspects, such as hepatorenal injuries, and dysregulation of the lipid and glucose metabolisms. Furthermore, hypoglycemia promoted by hyperinsulinemia may be a critical risk factor for mortality in circumstances in which fatty acid utilization is impaired during endotoxemia.

Impaired liver glucose production in a murine model of steatosis and endotoxemia: protection by inducible nitric oxide synthase

This study hypothesized that upregulation of inducible nitric oxide synthase (iNOS) would preserve the metabolic status of the liver under conditions of steatosis and acute inflammation. Wild-type C57BL/6J and C57BL/6 iNOS-knockout (-/-) mice were fed a choline-deficient ethionine-supplemented diet (CDE). Mice were also injected with 5 mg/kg lipopolysaccharide (LPS) to induce endotoxemia. Consumption of the CDE diet led to steatosis of the liver and decreased expression of the gluconeogenic genes compared with controls. LPS treatment exacerbated these effects because of inhibition of PGC-1alpha expression, which resulted in hypoglycemia. In steatotic livers, LPS-induced iNOS expression was enhanced. Comparison between wild-type and iNOS-knockout mice under these conditions demonstrated a protective role of iNOS against fatal hypoglycemia. Nitric oxide (NO) signaling effects were confirmed by treatment of hepatocytes in culture with an NO donor, which resulted in increased expression of PGC-1alpha and gluconeogenic genes. In conclusion, iNOS was found to act as a protective protein and provides a possible mechanism by which the liver preserves glucose homeostasis under stress.