Extent of the acute phase response in fulminant hepatic failure

Novel Serum Biomarkers Associated With Pediatric Hepatic Encephalopathy: A Systematic Review

BACKGROUND

The pathophysiology of pediatric hepatic encephalopathy (HE) is not well understood. Various serum biomarkers associated with HE may provide insight into its pathology, but their use and interpretation in clinical practice for diagnosis and prognostication remain undetermined. We sought to investigate reported correlations of serum biomarkers with presence and degree of HE in children.

METHODS

We conducted a systematic review of studies examining novel serum biomarkers and cytokines in association with HE that included children on PubMed, Embase, Lilacs, and Scopus. We utilized Covidence for abstract and text review by 2 independent reviewers for each study.

RESULTS

We reviewed 2824 unique publications; 15 met criteria for inclusion. Categories of biomarkers reported were inflammatory cytokines, products of amino acid metabolism, trace elements and vitamins, and hepatic and neuro biomarkers. Of 19 individual biomarkers, only 5 were measured in more than 1 study. Elevations in interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) were most commonly reported as associated with HE. Notably, we observed lower average IL-6 and TNF-alpha levels in pediatric-only studies compared to mixed age studies. Overall, high bias and poor applicability to our review question was observed. We encountered low numbers of studies with pediatric focus, and few conducted with low bias study designs.

CONCLUSION

Investigated biomarkers span a large range of categories and suggest potentially useful correlations with HE. Further well-designed prospective biomarker research is necessary to better elucidate the pathogenesis of HE in children and improve early detection and clinical care.

Should Procalcitonin Be Included in Acute Cholecystitis Guidelines? A Systematic Review

Background and Objectives: Acute cholecystitis (AC) is a common surgical emergency. Recent evidence suggests that serum procalcitonin (PCT) is superior to leukocytosis and serum C-reactive protein in the diagnosis and severity stratification of acute infections. This review evaluates the role of PCT in AC diagnosis, severity stratification, and management. Materials and Methods: PubMed, Embase, and Scopus were searched from inception till 21 August 2022 for studies reporting the role of PCT in AC. A qualitative analysis of the existing literature was conducted. Results: Five articles, including 688 patients, were included. PCT ≤ 0.52 ng/mL had fair discriminative ability (Area under the curve (AUC) 0.721, p < 0.001) to differentiate Grade 1 from Grade 2-3 AC, and PCT > 0.8 ng/mL had good discriminatory ability to differentiate Grade 3 from 1-2 AC (AUC 0.813, p < 0.001). PCT cut-off ≥ 1.50 ng/mL predicted difficult laparoscopic cholecystectomy (sensitivity 91.3%, specificity 76.8%). The incidence of open conversion was higher with PCT ≥ 1 ng/mL (32.4% vs. 14.6%, p = 0.013). A PCT value of >0.09 ng/mL could predict major complications (defined as open conversion, mechanical ventilation, and death). Conclusions: Current evidence is plagued by the heterogeneity of small sample studies. Though PCT has some role in assessing severity and predicting difficult cholecystectomy, and postoperative complications in AC patients, more evidence is necessary to validate its use.

Acute Liver Failure: Mechanisms of Disease and Multisystemic Involvement

Acute liver failure is accompanied by a pathologic syndrome common to numerous different etiologies of liver injury. This acute liver failure syndrome leads to potentially widespread devastating end-organ consequences. Systemic dysregulation and dysfunction is likely propagated via inflammation as well as underlying hepatic failure itself. Decoding the mechanisms of the disease process and multisystemic involvement of acute liver failure offers potential for targeted treatment opportunities and improved clinical outcomes in this sick population.

Plasminogen Activator Inhibitor-1 Reduces Tissue-Type Plasminogen Activator-Dependent Fibrinolysis and Intrahepatic Hemorrhage in Experimental Acetaminophen Overdose

Acetaminophen (APAP)-induced liver injury in mice is associated with activation of the coagulation cascade and deposition of fibrin in liver. Plasminogen activator inhibitor-1 (PAI-1) is an important physiological inhibitor of tissue-type plasminogen activator (tPA) and plays a critical role in fibrinolysis. PAI-1 expression is increased in both experimental APAP-induced liver injury and patients with acute liver failure. Prior studies have shown that PAI-1 prevents intrahepatic hemorrhage and mortality after APAP challenge, but the downstream mechanisms are not clear. We tested the hypothesis that PAI-1 limits liver-related morbidity after APAP challenge by reducing tPA-dependent fibrinolysis. Compared with APAP-challenged (300 mg/kg) wild-type mice, hepatic deposition of cross-linked fibrin was reduced, with intrahepatic congestion and hemorrhage increased in PAI-1-deficient mice 24 hours after APAP overdose. Administration of recombinant wild-type human PAI-1 reduced intrahepatic hemorrhage 24 hours after APAP challenge in PAI-1-/- mice, whereas a mutant PAI-1 lacking antiprotease function had no effect. Of interest, tPA deficiency alone did not affect APAP-induced liver damage. In contrast, fibrinolysis, intrahepatic congestion and hemorrhage, and mortality driven by PAI-1 deficiency were reduced in APAP-treated tPA-/-/PAI-1-/- double-knockout mice. The results identify PAI-1 as a critical regulator of intrahepatic fibrinolysis in experimental liver injury. Moreover, the results suggest that the balance between PAI-1 and tPA activity is an important determinant of liver pathology after APAP overdose.

Fibrin(ogen) drives repair after acetaminophen-induced liver injury via leukocyte αMβ2 integrin-dependent upregulation of Mmp12

BACKGROUND & AIMS

Acetaminophen (APAP)-induced liver injury is coupled with activation of the blood coagulation cascade and fibrin(ogen) accumulation within APAP-injured livers of experimental mice. We sought to define the role of fibrin(ogen) deposition in APAP-induced liver injury and repair.

METHODS

Wild-type, fibrinogen-deficient mice, mutant mice with fibrin(ogen) incapable of binding leukocyte αMβ2 integrin (Fibγ390-396A mice) and matrix metalloproteinase 12 (Mmp12)-deficient mice were fasted, injected with 300mg/kg APAP i.p. and evaluated at a range of time-points. Plasma and liver tissue were analyzed. Rescue of Fibγ390-396A mice was carried out with exogenous Mmp12. To examine the effect of the allosteric leukocyte integrin αMβ2 activator leukadherin-1 (LA-1), APAP-treated mice were injected with LA-1.

RESULTS

In wild-type mice, APAP overdose increased intrahepatic levels of high molecular weight cross-linked fibrin(ogen). Anticoagulation reduced early APAP hepatotoxicity (6h), but increased hepatic injury at 24h, implying a protective role for coagulation at the onset of repair. Complete fibrin(ogen) deficiency delayed liver repair after APAP overdose, evidenced by a reduction of proliferating hepatocytes (24h) and unresolved hepatocellular necrosis (48 and 72h). Fibγ390-396A mice had decreased hepatocyte proliferation and increased multiple indices of liver injury, suggesting a mechanism related to fibrin(ogen)-leukocyte interaction. Induction of Mmp12, was dramatically reduced in APAP-treated Fibγ390-396A mice. Mice lacking Mmp12 displayed exacerbated APAP-induced liver injury, resembling Fibγ390-396A mice. In contrast, administration of LA-1 enhanced hepatic Mmp12 mRNA and reduced necrosis in APAP-treated mice. Further, administration of recombinant Mmp12 protein to APAP-treated Fibγ390-396A mice restored hepatocyte proliferation.

CONCLUSIONS

These studies highlight a novel pathway of liver repair after APAP overdose, mediated by fibrin(ogen)-αMβ2 integrin engagement, and demonstrate a protective role of Mmp12 expression after APAP overdose.

LAY SUMMARY

Acetaminophen overdose leads to activation of coagulation cascade and deposition of high molecular weight cross-linked fibrin(ogen) species in the liver. Fibrin(ogen) is required for stimulating liver repair after acetaminophen overdose. The mechanism whereby fibrin(ogen) drives liver repair after acetaminophen overdose requires engagement of leukocyte αMβ2 integrin and subsequent induction of matrix metalloproteinase 12.

Prodromal fever indicates a high risk of liver failure in acute hepatitis B

OBJECTIVES

The role of prodromal fever in the clinical course of acute hepatitis B virus (HBV) infection is still largely unclear. This study was conducted to investigate the factors associated with prodromal fever and its role in the development of acute liver failure (ALF) in patients with acute hepatitis B (AHB).

METHODS

Inpatients with AHB diagnosed between January 2006 and December 2010 were evaluated and followed. Clinical manifestations, results of laboratory tests, and outcomes were compared between patients with and without prodromal fever. The diagnosis of AHB was based on the discrete onset of symptoms, jaundice, abnormal liver function tests, the detection of high-titer IgM antibody to hepatitis B core antigen (anti-HBc), and a compatible clinical history.

RESULTS

A total of 618 AHB inpatients were identified during the study period, of whom 102 (16.5%) had prodromal fever and 41 (6.6%) developed ALF. Prodromal fever indicated more severe liver injury and was independently associated with hepatitis B e antigen (HBeAg) negativity. The occurrence of ALF was more common in febrile patients than in non-febrile patients (18.6% vs. 4.3%, p<0.001). Multivariate logistic regression showed prodromal fever and temperature >38.0°C to be independently associated with the risk of ALF, with an odds ratio (95% confidence interval) of 3.5 (1.4-8.6) and 7.1 (2.6-19.7), respectively.

CONCLUSIONS

AHB patients with prodromal fever, which is associated with a lack of HBeAg due to HBV mutation, are at high risk of ALF. Febrile patients with AHB should be managed with particular care.

Role of Procalcitonin and C-Reactive Protein As Biomarkers of Infection in Children With Liver Disease

OBJECTIVES

Early and accurate identification of infection in patients with liver disease is challenging. The present study evaluated the role of procalcitonin (PCT) and C-reactive protein (CRP) as biomarkers of bacterial infection in children with liver disease.

METHODS

Demographic and clinical data of consecutive children admitted with acute liver failure (ALF) or decompensated chronic liver disease (DCLD) were collected. PCT and CRP were measured within 24 hours of admission. Blood and urine culture, chest x-ray, and ascitic fluid analysis were done.

RESULTS

One hundred sixty-four children (113 boys, age 76 [0.5-204] months, ALF 69, DCLD 95) were enrolled. Seventy-seven (47%) had infection. Most common site was ascitic fluid (n = 35), followed by urinary tract (n = 26), pneumonia (n = 22), and blood stream infection (n = 16). Twenty-one children had multiple-site infections, 18 had severe sepsis, and 36 had systemic inflammatory response syndrome. PCT and CRP correlated with infection severity, higher in severe sepsis (8.3 [3.5-38] ng/mL and 4.1 [0.3-13.8] mg/dL) than only infection (0.89 [0.1-8] ng/mL and 1.7 [0.32-24] mg/dL) and no infection (0.3 [0.1-6.75] ng/mL and 0.3 [0.1-4.16 mg/dL]). Systemic inflammatory response syndrome was more common in patients with infection (31/77 vs 5/87, P = 0.00). PCT (>0.5 ng/mL) and CRP (>0.6 mg/dL) performed better in DCLD (AUC of 0.90 and 0.83) compared with patients with ALF (AUC of 0.73 and 0.69).

CONCLUSIONS

PCT and CRP are reliable markers of infection and correlate with infection severity in children with liver disease. Their diagnostic accuracy is better in DCLD than ALF cases.

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.

Serum acute phase reactants hallmark healthy individuals at risk for acetaminophen-induced liver injury

Background

Acetaminophen (APAP) is a commonly used analgesic. However, its use is associated with drug-induced liver injury (DILI). It is a prominent cause of acute liver failure, with APAP hepatotoxicity far exceeding other causes of acute liver failure in the United States. In order to improve its safe use this study aimed to identify individuals at risk for DILI prior to drug treatment by searching for non-genetic serum markers in healthy subjects susceptible to APAP-induced liver injury (AILI).

Methods

Healthy volunteers (n = 36) received either placebo or acetaminophen at the maximum daily dose of 4 g for 7 days. Blood samples were taken prior to and after APAP treatment. Serum proteomic profiling was done by 2D SDS-PAGE and matrix-assisted laser desorption/ionization-time of flight-mass spectrometry. Additionally, the proteins C-reactive protein, haptoglobin and hemopexin were studied by quantitative immunoassays.

Results

One-third of study subjects presented more than four-fold increased alanine transaminase activity to evidence liver injury, while serum proteomics informed on 20 proteins as significantly regulated. These function primarily in acute phase and immune response. Pre-treatment associations included C-reactive protein, haptoglobin isoforms and retinol binding protein being up to six-fold higher in AILI susceptible individuals, whereas alpha1-antitrypsin, serum amyloid A, kininogen and transtyretin were regulated by nearly five-fold in AILI responders. When compared with published findings for steatohepatitis and cases of hepatocellular, cholestatic and mixed DILI, 10 proteins were identified as uniquely associated with risk for AILI, including plasminogen. Notably, this zymogen facilitates macrophage chemotactic migration and inflammatory response as reported for plasminogen-deficient mice shown to be resistant to APAP hepatotoxicity. Finally, analysis of a publicly available database of gene expression profiles of cultures of human hepatocytes treated with drugs labeled as no- (n = 8), low- (n = 45) or most-DILI-concern (n = 39) confirmed regulation of the identified biomarkers to demonstrate utility in predicting risk for liver injury.

Conclusions

The significant regulation of acute phase reactants points to an important link between AILI and the immune system. Monitoring of serum acute phase reactants prior to drug treatment may contribute to prevention and management of AILI, and may also be of utility for other drugs with known liver liabilities.

Elevated levels of the long pentraxin 3 in paracetamol-induced human acute liver injury

OBJECTIVES

Pentraxin 3 (PTX3) is a long pentraxin with diverse humoral innate immune functions. The aims of this study were to measure levels of PTX3 and C-reactive protein (CRP), a hepatocyte-derived short pentraxin, in patients after acute liver injury.

METHODS

PTX3 and CRP levels were measured in a total of 60 patients [48 paracetamol overdose (POD), 12 non-POD]. PTX3 expression was assessed by immunohistochemical analysis in explanted liver tissue.

RESULTS

Admission PTX3 levels were significantly higher in POD acute liver failure (ALF) patients compared with POD non-ALF patients (P=0.0005) and non-POD patients (P=0.004). PTX3 levels in POD patients who died or required orthotopic liver transplantation (OLT, n=14) were significantly higher compared with those in spontaneous survivors (n=34, P=0.0011). The area under the receiver operator characteristic for PTX3 for death/OLT in POD patients was 0.80 (95% confidence interval 0.67-0.93). PTX3 levels were significantly higher in those POD patients who developed the systemic inflammatory response syndrome (P=0.001). Conversely, admission CRP levels were significantly lower in POD compared with non-POD patients (P=0.011), with no significant differences between survivors and nonsurvivors. After emergency OLT, PTX3 levels fell markedly; in contrast, CRP levels rapidly increased. Immunohistochemical analysis showed PTX3 expression in sinusoidal lining cells of a normal liver, infiltrating inflammatory cells in patients with ALF, and in a membranous distribution on injured hepatocytes in POD patients.

CONCLUSION

Increased PTX3 levels are associated with adverse outcomes following POD, suggesting that the humoral innate immune system plays an underrecognized role in this condition.

Inflammatory cascades driven by tumor necrosis factor-alpha play a major role in the progression of acute liver failure and its neurological complications

BACKGROUND/AIMS

Acute liver failure (ALF) due to ischemic or toxic liver injury is a clinical condition that results from massive loss of hepatocytes and may lead to hepatic encephalopathy (HE), a serious neuropsychiatric complication. Although increased expression of tumor necrosis factor-alpha (TNF-α) in liver, plasma and brain has been observed, conflicting results exist concerning its roles in drug-induced liver injury and on the progression of HE. The present study aimed to investigate the therapeutic value of etanercept, a TNF-α neutralizing molecule, on the progression of liver injury and HE in mice with ALF resulting from azoxymethane (AOM) hepatotoxicity.

METHODS/PRINCIPAL FINDINGS

Mice were administered saline or etanercept (10 mg/kg; i.p.) 30 minutes prior to, or up to 6 h after AOM. Etanercept-treated ALF mice were sacrificed in parallel with vehicle-treated comatose ALF mice and controls. AOM induced severe hepatic necrosis, leading to HE, and etanercept administered prior or up to 3 h after AOM significantly delayed the onset of coma stages of HE. Etanercept pretreatment attenuated AOM-induced liver injury, as assessed by histological examination, plasma ammonia and transaminase levels, and by hepatic glutathione content. Peripheral inflammation was significantly reduced by etanercept as shown by decreased plasma IL-6 (4.1-fold; p<0.001) and CD40L levels (3.7-fold; p<0.001) compared to saline-treated ALF mice. Etanercept also decreased IL-6 levels in brain (1.2-fold; p<0.05), attenuated microglial activation (assessed by OX-42 immunoreactivity), and increased brain glutathione concentrations.

CONCLUSIONS

These results indicate that systemic sequestration of TNF-α attenuates both peripheral and cerebral inflammation leading to delayed progression of liver disease and HE in mice with ALF due to toxic liver injury. These results suggest that etanercept may provide a novel therapeutic approach for the management of ALF patients awaiting liver transplantation.

The evolving story of macrophages in acute liver failure

Acute liver failure (ALF) remains a worldwide problem. The innate immune system acts as an important regulator of ALF. Kupffer cells (KCs), the resident macrophages in liver, play a key role in liver innate immune response. Recent researches have shown that macrophages display a remarkable plasticity and can differentiate into functionally diverse subsets. However, the dynamic polarized phenotypes and functional status of macrophages at different stage of ALF are not clear. In this paper, we present a review of evidence that KCs play a significant role in the pathogenesis of ALF, including the phenotype and functions of macrophages, signaling pathways involved in macrophage functional status and cell-crosstalks of KCs with other immune cells. More information on macrophages will promote a better understanding of the cellular molecular mechanisms of ALF and provide new insights for the development of therapeutic targets for ALF.

Lack of therapeutic effects of gabexate mesilate on the hepatic encephalopathy in rats with acute and chronic hepatic failure

BACKGROUND AND AIM

Inflammation plays a pivotal role in liver injury. Gabexate mesilate (GM, a protease inhibitor) inhibits inflammation by blocking various serine proteases. This study examined the effects of GM on hepatic encephalopathy in rats with acute and chronic liver failure.

METHODS

Acute and chronic liver failure (cirrhosis) were induced by intraperitoneal TAA administration (350 mg/kg/day for 3 days) and common bile duct ligation, respectively, in male Sprague-Dawley rats. Rats were randomized to receive either GM (50 mg/10 mL/kg) or saline intraperitoneally for 5 days. Severity of encephalopathy was assessed by the Opto-Varimex animal activity meter and hemodynamic parameters, mean arterial pressure and portal pressure, were measured (only in chronic liver failure rats). Plasma levels of liver biochemistry, ammonia, nitrate/nitrite, interleukins (IL) and tumor necrosis factor (TNF)-alpha were determined.

RESULTS

In rats with acute liver failure, GM treatment significantly decreased the plasma levels of alanine aminotransferase (P = 0.02), but no significant difference of motor activity, plasma levels of ammonia, IL-1beta, IL-6, IL-10 and TNF-alpha or survival was found. In chronic liver failure rats, GM significantly lowered the plasma TNF-alpha levels (P = 0.04). However, there was no significant difference of motor activity, other biochemical tests or survival found. GM-treated chronic liver failure rats had higher portal pressure (P = 0.04) but similar mean arterial pressure in comparison with saline-treated rats.

CONCLUSIONS

Chronic GM treatment does not have a major effect on hepatic encephalopathy in rats with TAA-induced acute liver failure and rats with chronic liver failure induced by common bile duct ligation.

Role of monocytes and macrophages in experimental and human acute liver failure

Acute liver failure (ALF) is a devastating clinical syndrome characterised by progressive encephalopathy, coagulopathy, and circulatory dysfunction, which commonly leads to multiorgan failure and death. Central to the pathogenesis of ALF is activation of the immune system with mobilisation of cellular effectors and massive production of cytokines. As key components of the innate immune system, monocytes and macrophages are postulated to play a central role in the initiation, progression and resolution of ALF. ALF in humans follows a rapidly progressive clinical course that poses inherent difficulties in delineating the role of these pivotal immune cells. Therefore, a number of experimental models have been used to study the pathogenesis of ALF. Here we consider the evidence from experimental and human studies of ALF on the role of monocytes and macrophages in acute hepatic injury and the ensuing extrahepatic manifestations, including functional monocyte deactivation and multiple organ failure.

Impact of fulminant hepatic failure in C-reactive protein?

INTRODUCTION

Fulminant hepatic failure (FHF) refers to the rapid development of severe acute liver injury with impaired synthetic function, coagulopathy, and encephalopathy in a person who previously had a normal liver or had a well-compensated liver disease. It is a rare complication in critically ill patients and carries a very bad prognosis. Serum C-reactive protein (CRP), a useful marker of infection, is produced exclusively by the liver.

AIM

The aim of this study was to assess CRP concentrations in patients with FHF.

METHODS

We prospectively identified patients with sepsis and FHF treated at the intensive care unit (ICU). Data collected included admission diagnosis, medical history, systemic inflammatory response syndrome criteria, Acute Physiologic and Chronic Health Evaluation II, and Sequential Organ Failure Assessment scores. C-reactive protein and white cell count were measured at admission and then daily until ICU discharge.

RESULTS

We included 7 patients with FHF and sepsis. Six patients died with severe multiple organ failure. Six patients were already admitted with FHF, with the remaining one being diagnosed at the 26th day of ICU stay. All patients present severe coagulopathy. In all septic patients, despite clinical deterioration, CRP levels were markedly decreased sometimes reaching undetectable levels.

CONCLUSION

In septic patients with FHF, CRP is more a marker of severe liver dysfunction and should not be used as a marker of infection. As a result, in a patient admitted with a very high suspicion of infection and an abnormally low CRP concentration or with a marked CRP decline despite persistent septic shock, severe hepatic failure should be ruled out.

An Update on C-reactive Protein for Intensivists

This review aims to summarise the physiology of C-reactive protein (CRP), its possible roles and limitations as an inflammatory and infective marker in intensive care medicine, and also the emerging roles of CRP in the pathogenesis of cardiovascular and autoimmune diseases. Observational and animal studies on uses of CRP were retrieved from the PubMed database without any language restrictions. Quantitative data were not pooled because of the heterogeneity of patient characteristics and disparate ways in which CRP was studied. Serum CRP concentrations are determined by the synthetic rate of its production in the liver regulated predominantly by interleukin-6. It has a half-life of 19 hours and is relatively slow in its onset and offset in response to an acute inflammatory process when compared to procalcitonin. It has some favourable properties and limitations as an inflammatory marker. An elevated CRP concentration is not specific to infections and the absolute CRP concentrations cannot be used to differentiate between bacterial, fungal and severe viral infections. The dynamic response of CRP to therapy that aims to modify the underlying inflammatory process and the clinical context of a patient are of pivotal importance when CRP concentrations are interpreted. CRP is found to be a significant partaker and prognostic factor in a wide range of cardiovascular and chronic diseases. In summary, CRP concentration is an important prognostic factor of many acute and chronic diseases. Serial CRP measurements may be useful to reflect a patient's response to therapy that aims to modify the underlying inflammatory process.

The importance of immune dysfunction in determining outcome in acute liver failure

Acute liver failure (ALF) shares striking similarities with septic shock with regard to the features of systemic inflammation, progression to multiple organ dysfunction and functional immunoparesis. While the existence of opposing systemic pro- and anti-inflammatory profiles resulting in organ failure and immune dysfunction are well recognised in septic shock, characterization of these processes in ALF has only recently been described. This review explores the evolution of the systemic inflammation in acute liver failure, its relation to disease progression, exacerbation of liver injury and development of innate immune dysfunction and extra-hepatic organ failure as sequelae. Defects in innate immunity are described in hepatic and extra-hepatic compartments. Clinical studies measuring levels of pro- and anti-inflammatory cytokines and expression of the antigen presentation molecule HLA-DR on monocytes, in combination with ex-vivo experiments, demonstrate that the persistence of a compensatory anti-inflammatory response syndrome, leading to functional monocyte deactivation, is a central event in the evolution of systemic immune dysfunction. Accurate immune profiling in ALF may permit the development of immunomodulatory strategies in order to improve outcome in this condition.

Safety and efficacy of N-acetylcysteine in children with non-acetaminophen-induced acute liver failure

Acute liver failure (ALF) carries a high mortality in children. N-acetylcysteine (NAC), an antioxidant agent that replenishes mitochondrial and cytosolic glutathione stores, has been used in the treatment of late acetaminophen-induced ALF and non-acetaminophen-induced ALF. In our unit, NAC was introduced as additional treatment for non-acetaminophen-induced ALF in 1995. The aim of this study was to evaluate the safety and efficacy of NAC in children with ALF not caused by acetaminophen poisoning. A retrospective review of medical records of 170 children presenting with nonacetaminophen-induced ALF between 1989 and 2004 was undertaken. ALF was defined as either international normalized ratio of prothrombin time (INR) > 2 and abnormal liver function or INR >1.5 with encephalopathy and abnormal liver function. Children were divided into the following groups: Group 1 (1989-1994), standard care (n = 59; 34 [58%] male; median age 2.03 yr, range 0.003-15.8 yr); and Group 2 (1995-2004), standard care and NAC administration (n = 111; 57 [51%] male; median age 3.51 yr, range 0.005-17.4 yr). NAC was administered as a continuous infusion (100 mg/kg/24 hours) until INR < 1.4, death, or liver transplantation (LT). The median duration of NAC administration in Group 2 was 5 (range, 1-77) days. Complications were noted in 8 (10.8%) children: rash in 3, arrhythmia in 3, and dizziness and peripheral edema in 1. One child had an allergic reaction (bronchospasm) and NAC was stopped. A total of 41 (71%) children in Group 1 vs. 85 (77%) in Group 2 required admission to intensive care, P = not significant (ns). The length of intensive care stay was 6 (range, 1-58) days in Group 1 vs. 5 (range, 1-68) days in Group 2, P = ns and length of hospital stay was 25 (range, 1-264) days vs. 19 (range, 1-201) days, P = 0.05. The 10-yr actuarial survival was 50% in Group 1 compared to 75% in Group 2, P = 0.009. Survival with native liver occurred in 13 (22%) in Group 1 vs. 48 (43%) in Group 2, P = 0.005; 15 (25%) in Group 1 died without transplant vs. 21 (19%) in Group 2, P = ns; and LT was performed in 32 (54%) vs. 42 (38%), P = ns. Death after transplantation occurred in 15 (39%) in Group 1 vs. 8 (16%) in Group 2, P = 0.02. In conclusion, NAC is safe in non-acetaminophen-induced ALF. In this retrospective study NAC was associated with a shorter length of hospital stay, higher incidence of native liver recovery without transplantation, and better survival after transplantation.

Treatment of fulminant hepatic failure in rats using a bioartificial liver device containing porcine hepatocytes producing interleukin-1 receptor antagonist

Fulminant hepatic failure (FHF) is a serious clinical condition that is associated with high mortality. There is evidence that FHF is an inflammatory disease, which is supported clinically by elevated serum levels of cytokines. In an effort to develop hepatocytes with additional functions for use in our bioartificial liver (BAL) device, we focused on interleukin-1 (IL-1) blockade as a therapeutic modality. Primary porcine hepatocytes were isolated from the livers of miniature swine and then transfected with an adenoviral vector encoding human interleukin-1 receptor antagonist (AdIL-1Ra). The transfected hepatocytes secreted human IL-1Ra. These transfected hepatocytes were incorporated into a flat-plate BAL device to evaluate their efficacy in treating D-galactosamine (GalN)- induced FHF in a rat model. After extracorporeal perfusion with the BAL device containing the transfected hepatocytes, there were significant reductions in the plasma levels of hepatic enzymes (aspartate aminotransferase and alanine aminotransferase) and cytokines (IL-1 and IL-6), indicating a beneficial effect. Animal survival was significantly improved in the treated group compared to the control group. These experiments demonstrate that combining inflammatory cytokine blockade with a functional BAL device may be an effective therapeutic option in the treatment of FHF.

Reduced monocyte HLA-DR expression: a novel biomarker of disease severity and outcome in acetaminophen-induced acute liver failure

Acute liver failure (ALF) shares striking similarities with septic shock where a decrease in HLA-DR expression on monocytes is associated with disease severity and predicts outcome. We investigated monocyte HLA-DR expression in ALF in relation to inflammatory mediator levels and clinical outcome. Monocyte HLA-DR expression was determined in 50 patients with acetaminophen-induced ALF (AALF) and 20 non-acetaminophen-induced ALF (NAALF). AALF patients were divided into dead/transplanted (AALF-NS, n = 26) and spontaneous survivors (AALF-S, n = 24). Fifty patients with chronic liver disease (CLD) and 50 healthy volunteers served as controls. Monocyte HLA-DR expression was determined by double-color flow-cytometry with monoclonal antibodies detecting HLA-DR and monocyte specific CD14. Serum levels of interleukin (IL) -4, -6, -10, tumor necrosis factor (TNF)-alpha and interferon (IFN)-gamma were concomitantly measured by ELISA. Compared to healthy volunteers (75%) and CLD (67%) monocyte HLA-DR percentage expression was lower in AALF (15%, P < .001) and NAALF (22 %, P < .001). Compared to AALF-S, AALF-NS had lower monocyte HLA-DR % (11% vs. 36%, P < .001) and higher levels of IL-4, IL-6, IL-10 and TNF-alpha (P < .001). HLA-DR percentage negatively correlated with INR, blood lactate, pH and levels of encephalopathy (r = -0.8 to -0.5, P < .01), IL-10 (r = -0.8, P < .0001), TNF-alpha (r = -0.4, P = .02). HLA-DR percentage level <or=15% has a 96% sensitivity and 100% specificity and 98% accuracy in predicting poor prognosis. In conclusion, the strong relationship of monocyte HLA-DR expression with indices of disease severity, mediators of inflammation and outcome indicates a key role for this molecule as a biomarker of disease severity and prognosis.

Protective effect of s-allyl cysteine and s-propyl cysteine on acetaminophen-induced hepatotoxicity in mice

In vivo protective effects of s-allyl cysteine (SAC) and s-propyl cysteine (SPC) against acetaminophen-induced hepatotoxicity in Balb/cA mice were studied. SAC and SPC at 1g/L were added into drinking water for four weeks and followed by acetaminophen treatment. Acetaminophen treatment significantly depleted glutathione content, increased oxidation stress and elevated alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities (P < 0.05); however, the intake of SAC or SPC significantly alleviated glutathione depletion and the elevation of ALT and AST, enhanced glutathione peroxidase activity, and lowered malondialdehyde formation (P < 0.05). Plasma levels of C-reactive protein (CRP), von Willebrand factor (vWF), IL-6, IL-10 and TNF-alpha were significantly increased by acetaminophen treatment (P < 0.05); and SAC or SPC intake significantly suppressed acetaminophen-induced elevation of CRP, vWF and the three cytokines (P < 0.05). Acetaminophen treatment also significantly increased plasminogen activator inhibitor-1 (PAI-1) activity and plasma fibrinogen level, and decreased antithrombin III (AT-III) and protein C activities (P < 0.05). SAC or SPC intake alleviated AT-III and protein C reduction (P < 0.05); but did not affect PAI-1 activity and plasma fibrinogen level (P > 0.05). These data suggest that SAC and SPC are potential multiple-protective agents against acetaminophen-induced hepatotoxicity.

Nitric oxide and pro-inflammatory cytokines in acute hepatitis B

Background: Experimental studies demonstrate that hepatitis B virus may induce nitric oxide (NO) production in infected hepatocytes. Its presence in acute hepatitis B patients has not been studied. Methods: Serum levels of nitric oxide and its regulatory pro-inflammatory cytokines were detected in 15 patients with uncomplicated acute hepatitis B, 19 blood donors and 15 chronic hepatitis B patients. Cytokines were determined with an immunoassay. Nitric oxide was measured as the serum metabolic products of nitrates and nitrites using a modification of the Griess reaction. Results: All detected cytokines were increased in acute hepatitis B patients compared to healthy controls (p<0.001 for TNF-alpha, p<0.05 for IL-6, p<0.001 for IL1-beta and p<0.001 for IFN-gamma). High serum levels of nitric oxide were found in acute hepatitis B patients (156.96+/-9.76 micromol/l) compared to healthy controls (51+/-6.2 micromol/l, p<0.001) and chronic hepatitis B patients (63.97+/-3.78 micromol/l, p<0.001). No significant correlations were found between NO, cytokine levels and transaminases. Conclusions: High levels of nitric oxide and its regulatory cytokines were found in a group of patients with uncomplicated acute hepatitis B. The exact role of NO in the disease pathogenesis and outcome needs to be studied further.

Lack of gp130 expression in hepatocytes promotes liver injury

BACKGROUND & AIMS

Interleukin 6 (IL-6) contributes via its signal transducer gp130 to the acute phase response (APR) in hepatocytes. Recent studies indicated that IL-6 is involved in the regulation of different pathophysiologic conditions of the liver. To define the IL-6-dependent intracellular pathways more specifically, we generated a hepatocyte-specific gp130 knockout mouse.

METHODS

Hepatocyte-specific gp130-deficient mice were generated using the Cre-loxP system. Expression of the Cre recombinase was under the control of a hepatocyte-specific control element. Adult mice were challenged with IL-6, oncostatin M (OSM), and LPS.

RESULTS

Cre expression started at day 10.5 postconception, and a complete deletion of gp130 in hepatocytes was found at day 14 during liver development. The adult liver of these mice showed no abnormalities; however, after IL-6 and OSM stimulation, gp130-dependent pathways (STAT3, APR gene expression) were completely blocked in the liver of these animals. Additionally, challenging hepatocyte-specific gp130 knockout animals with lipopolysaccharides (LPS) lead to an onset of acute liver injury with an increase of hepatocyte apoptosis associated with elevated tumor necrosis factor alpha (TNF-alpha) serum levels and reduced nuclear factor kappaB (NF-kappaB) activation in hepatocytes.

CONCLUSIONS

Our findings demonstrate that gp130 is of minor relevance for embryonal development of hepatocytes. However, the molecule has an essential role in controlling acute phase gene expression and provides hepatocellular protection after LPS challenge.

Interleukin 6/gp130-dependent pathways are protective during chronic liver diseases

The contribution of the acute phase inducer interleukin 6 (IL-6) in the pathogenesis of liver diseases is yet unclear. Our analysis showed enhanced expression of IL-6 in livers derived from patients with acute and chronic liver diseases. Additionally, IL-6 plasma levels were significantly increased in patients with chronic liver diseases and showed an inverse correlation with biochemical markers of liver function and a positive correlation with inflammatory markers, signs of portal hypertension, and the degree of liver fibrosis. To prove the relevance of these clinical findings, we applied the tetrachlorcarbonide (CCl(4)) model to conditional knockout animals (Cre/loxP system) for gp130, the common signal transducer of IL-6 family cytokines. Cre recombinases were expressed through a hepatocyte (AlfpCre) and a ubiquitous (MxCre) control element. Gp130 deleted mice had a totally abolished STAT3 activation and acute phase response induction, but gp130 deletion had no effect on the degree of acute liver injury and subsequent hepatocyte proliferation. In contrast, during chronic liver injury induced by biweekly application of CCl(4), deletion of the gp130 receptor in nonparenchymal liver cells and not hepatocytes resulted in fibrosis progression. In conclusion, our experiments indicate an involvement of IL-6 in the pathogenesis of liver diseases and suggest a protective role of IL-6/gp130-dependent pathways in nonparenchymal liver cells during fibrosis progression in chronic liver diseases. (Hepatology 2003;38:218-229).

Immunohistochemical expression of C-reactive protein in squamous cell carcinoma of the esophagus - significance as a tumor marker

C-reactive protein (CRP) is a prototype acute phase protein which has been known to be synthesized in hepatocytes. Although serum elevation of CRP has been reported to be an indicator of the unfavorable outcome of the patients in some malignant tumors, the expression of the protein in carcinoma cells has not been investigated. The aim of the current study was to assess the immunohistochemical expression of CRP in squamous cell carcinoma (SCC) of the esophagus and to find its biological significance. Immunohistochemical examination for CRP expression was performed for 37 advanced esophageal SCCs with the depth of T2, T3 or T4, which had been surgically resected without preoperative therapy for the patients. Eighteen carcinomas (48.6%) demonstrated immunohistochemical CRP expression. Univariate analysis showed that the prognosis of the patients with esophageal SCCs expressing CRP was significantly worse than that in patients with tumors without CRP expression (P=0.017). Moreover, CRP expression was found to be an independent prognosticator in patients with esophageal SCCs in the multivariate analysis (P=0.036). To the best of authors' knowledge, this is the first report that demonstrated the possible carcinoma-related expression of CRP in SCCs of the esophagus and its biological significance as the prognosticator of the patients.

Activin A and follistatin in acute liver failure

BACKGROUND

Liver regeneration may be impaired in acute liver failure due to either inhibition of the proliferative response or ongoing liver cell death. Activin A, a member of the TGFbeta superfamily, inhibits hepatocyte DNA synthesis and induces apoptosis.

METHODS

Levels of activin A and its binding protein follistatin in the serum of 23 patients with acute liver failure were determined by enzyme-linked immunosorbent assay.

RESULTS

Serum activin A was significantly increased in acute liver failure patients (median 2.15 ng/ml, range 0.28-6.87 ng/ml) compared to normal controls (median 0.25 ng/ml, range 0.19-0.53 ng/ml; = 10; 0.001). However, this was not linked to the final disease outcome. Higher levels of activin A were found in the serum of patients with acute liver failure due to paracetamol overdose (median 2.87 ng/ml, range 0.72-6.87 ng/ml; = 17) than in patients with acute liver failure due to non-A to E hepatitis (median 1.10 ng/ml, range 0.28-2.70 ng/ml; = 6; 0.05). Serum follistatin was also increased in acute liver failure patients (median 2.84 ng/ml, range 0.57-13.24 ng/ml) compared to normal controls (median 0.68 ng/ml, range 0.32-3.70 ng/ml; 0.01).

CONCLUSION

Serum activin A is increased in acute liver failure and could be a factor in the inhibition of liver regeneration.

Liver gene regulation in rats following both 70 or 90% hepatectomy and endotoxin treatment

BACKGROUND

The metabolic state effect of liver failure on liver gene regulation was evaluated in a rat model.

METHODS

Following 70 or 90% hepatectomy and lipopolysaccharide or vehicle treatment at intervals up to 24 h, the liver remnants were analyzed for mRNA levels for acute-phase, liver-specific and growth-related proteins.

RESULTS

After 70% hepatectomy mRNA for alpha 1-acid glycoprotein, alpha 2-macroglobulin, thiostatin and fibrinogen, haptoglobin increased three- to sevenfold (P < 0.05), and mRNA for cyclin D and histone 3 increased seven- and 15-fold (P < 0.05), respectively. After lipopolysaccharide injection and 70% hepatectomy were done, mRNA for acute-phase proteins raised significantly (P < 0.05), more to five to 20-fold, while mRNA for growth-related proteins raised significantly (P < 0.05) less to three- to fourfold. After 90% hepatectomy, acute-phase protein mRNA increased five- to ninefold (P < 0.05) more than after 70% hepatectomy, while mRNA for histone 3 and cyclin D did not increase within 24 h, which indicates a delayed growth after 90% hepatectomy. In 90% of hepatectomized rats treated with lipopolysaccharide, acute-phase protein mRNA raised three- to sixfold (P < 0.05) less than after vehicle treatment.

CONCLUSION

In endotoxemia from liver failure, the synthesis of acute-phase proteins is upregulated by gene regulation at the expense of that for regeneration, which may be an appropriate response for immediate survival. In severe liver failure, endotoxin may interfere with the appropriate gene regulation.

Energy expenditure in acetaminophen-induced fulminant hepatic failure

OBJECTIVE

To determine energy expenditure in critically ill patients suffering from acetaminophen-induced fulminant hepatic failure and compare it with values obtained in matched, healthy control subjects and in patients studied during the anhepatic period of elective liver transplantation.

DESIGN

Prospective, controlled, observational study.

SETTING

A ten-bed intensive therapy unit and a liver transplant unit at a University teaching hospital.

PATIENTS AND SUBJECTS

Sixteen patients suffering from acetaminophen-induced fulminant hepatic failure who were sedated, paralyzed, and mechanically ventilated; 16 age-, gender-, and weight-matched, awake, healthy control subjects; and 16 patients with chronic liver disease, undergoing elective liver transplantation, who were studied during the anhepatic period of surgery.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The mean energy expenditure was calculated in each case for a 30-min period, using indirect calorimetry. In the patients undergoing liver transplantation, measurements were performed after clamping the hepatic veins and recipient hepatectomy. Energy expenditure was markedly increased in the fulminant hepatic failure group (mean energy expenditure, 4.05 [SD 0.52] kJ x kg(-1) x hr(-1)), in comparison with healthy control subjects (mean, 3.44 [0.27] kJ x kg(-1) x hr(-1); mean difference, 18%; p < .001) and in comparison with patients during the anhepatic period of liver transplantation (mean, 3.15 [0.61] kJ x kg(-1) x hr(-1); mean difference, 29%; p < .001). These differences were even more pronounced when a correction factor for differences in core temperature was included in the calculation. Harris-Benedict predictions of energy expenditure were unreliable in the patients with acute liver failure. No correlations were found among energy expenditure and hemodynamic variables, the requirement for vasoconstrictors, or the presence of renal failure.

CONCLUSIONS

Despite the loss of functioning liver cell mass, the metabolic rate is substantially increased in patients with acetaminophen-induced fulminant hepatic failure. This finding is consistent with the marked systemic inflammatory response, which accompanies acute hepatic failure. The Harris-Benedict equation is unreliable when an estimation of energy expenditure is required in patients with this condition.

Fulminant hepatic failure

In recent years, considerable progress has been made in developing specific and supportive medical measures that have improved prognosis in FHF. Although new techniques for cell culture and perfusion have also resulted in a number of promising devices for the provision of temporary liver support, their clinical efficacy is as yet uncertain. Controlled multicenter trials in well-defined patient groups and with standardized outcome measures will be essential to evaluate the clinical value of these devices properly. The same considerations must also apply in assessing the efficacy of hepatocyte transplantation in FHF. A better understanding of mechanisms responsible for liver cell death and multiorgan failure, and the development of strategies to enhance liver regeneration may, in the future, allow a more targeted approach to therapy.

Plasma cytokine levels and coagulation and complement activation during use of the extracorporeal liver assist device in acute liver failure

Multiple organ failure frequently occurs in patients with acute liver failure, and this has been associated with increased cytokine production. Treatment by hemoperfusion with an extracorporeal liver assist device (ELAD) containing human liver-derived cells was performed in 12 patients with acute liver failure. Over the first 6 h, there were significant increases in plasma tumor necrosis factor alpha (TNFalpha; from 114+/-54 pg/ml [mean+/-SEM] to 236+/-161 pg/ml, p < 0.05) and interleukin (IL)-6 (260+/-121 pg/ml to 445+/-149 pg/ml, p < 0.05) but not in interferon gamma (IFNgamma). A similar pattern with a small peak increase was observed for complement C5b-9 complex. Plasma C-reactive protein (CRP) and thrombin antithrombin (TAT) III complex showed small peaks after 24 h of ELAD hemoperfusion. No such changes were seen in 12 control patients with acute liver failure who were treated with intensive care alone. These transitory effects, without changes in blood pressure, are likely to be due to the contact of the blood with the dialyzer membrane. There was no evidence of the clearance of cytokines by the ELAD.

Removal of endotoxin and cytokines by plasma exchange in patients with acute hepatic failure

OBJECTIVES

To compare the circulating concentrations of endotoxin and cytokines in patients with fulminant hepatitis and patients with the severe form of acute hepatitis, and to assess the effects of plasma exchange on the circulating concentrations of these inflammatory mediators in patients with acute hepatic failure.

DESIGN

Prospective, consecutive entry study of patients meeting fulminant hepatitis criteria and the severe form of acute hepatitis criteria.

SETTING

University hospital, intensive care unit.

PATIENTS

Five patients with fulminant hepatitis, eight patients with the severe form of acute hepatitis, two patients with acute-on-chronic hepatic failure, and one patient with postoperative hepatic failure.

INTERVENTIONS

Plasma endotoxin, serum tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta, and IL-6 were determined on admission in five patients with fulminant hepatitis and eight patients with the severe form of acute hepatitis. Circulating concentrations of the inflammatory mediators were measured before and after a single course of plasma exchange in eight patients with acute liver failure, including five patients with fulminant hepatitis, two patients with acute-on-chronic hepatic failure, and one patient with postoperative hepatic failure.

MEASUREMENTS AND MAIN RESULTS

TNF-alpha and IL-6 in patients with fulminant hepatitis were significantly higher than in patients with the severe form of acute hepatitis, whereas endotoxin concentrations did not differ between patients with fulminant hepatitis or the severe form of acute hepatitis. IL-1beta was not detectable in patients with either fulminant hepatitis or the severe form of acute hepatitis. Plasma endotoxin concentrations decreased immediately after plasma exchange. Serum concentrations of TNF-alpha and IL-6 were significantly lower after plasma exchange than before plasma exchange.

CONCLUSION

TNF-alpha and IL-6 may be important in the pathogenesis of the clinical symptoms that differentiate fulminant hepatitis from the severe form of acute hepatitis, and plasma exchange removes these inflammatory mediators from the circulation of patients with severe liver disease.

New approaches to supporting the failing liver

With the continued, growing disparity between the numbers of organ donations and patients waiting for liver transplantation, various efforts have been made to optimize the allocation of organs, as well as to devise means to support the failing liver. Over the years, the development of bioartificial liver-assist devices has aimed at replacing the three main functions of hepatocytes, which are synthetic, metabolic, and excretory. The application of porcine hepatocytes in humans to carry out biotransformation, as well as other metabolic functions and refinement of the membrane separator, have yielded some promising results in supporting patients with acute liver failure. Further advances will need to be made before these bioartificial devices can be considered for routine application in clinical settings.

Pro-inflammatory cytokine release and mediation of the acute phase protein response in fulminant hepatic failure

OBJECTIVE

To study the relationship between interleukin-6 (IL-6), tumour necrosis factor (TNF) and the acute phase protein C-reactive protein (CRP) in patients with fulminant hepatic failure (FHF) and to investigate the potential of peripheral blood mononuclear cells (PBMC) isolated from these patients to stimulate CRP production by isolated human hepatocytes in vitro.

SETTING

Patients with FHF were studied at the time of their admission to the intensive care unit.

STUDY DESIGN

Serum TNF and IL-6 were measured in 12 patients with FHF, PBMC from 6 of these patients were then cultured in the presence and absence of lipopolysaccharides (LPS). TNF and IL-6 in serum and supernatants were measured by ELISA. PBMC supernatants were added to isolated human hepatocytes and CRP production was measured.

RESULTS

Serum IL-6 (348 +/- 172 pg/ml) and TNF (118.5 +/- 15.5 pg/ml) were elevated compared with healthy controls (not detected) and these observations were matched by elevated serum CRP in patients with FHF (38.9 +/- 7 mg/l). Both the production of IL-6 and TNF by PBMC isolated from patients with FHF and the potential of supernatants from these cells to stimulate CRP production by hepatocytes in vitro was significantly reduced compared with controls.

CONCLUSION

Despite the observation that patients with FHF have an elevated hepatic acute phase response, PBMC from patients with FHF have reduced potential to produce IL-6 and TNF and elicit an acute phase response in vitro by the time of patient admission to the intensive care unit. One explanation for this observation is early activation and exhaustion of PBMC in vivo.

Plasma levels and hepatic mRNA expression of transforming growth factor-beta1 in patients with fulminant hepatic failure

BACKGROUND/AIMS

Transforming growth factor-beta1 is an important cytokine involved in cell growth and inflammation which has been shown to be inhibitory to hepatic DNA synthesis. The aim of this study was to investigate the plasma levels and hepatic mRNA expression of transforming growth factor-beta1 in patients with fulminant hepatic failure in whom liver regeneration may be impaired.

METHODS

Plasma levels of transforming growth factor-beta1 and human hepatocyte growth factor were measured in 57 fulminant hepatic failure patients and 20 healthy volunteers by ELISA. Northern blot analysis of transforming growth factor-beta1 and H3 histone, a marker for liver proliferation, was performed in liver tissue of 14 fulminant hepatic failure patients.

RESULTS

The plasma levels of total transforming growth factor-beta1 in fulminant hepatic failure patients on admission (median 38.8 ng/ml, range 8.4-108 ng/ml) were significantly higher than those in control subjects (23.0 ng/ml, 8.5-34.9 ng/ml, p<0.001). Significantly higher levels were observed in non-A, non-B hepatitis patients (57.9 ng/ml, 38.8-108 ng/ml, n=10, p<0.001) compared to patients with paracetamol overdose (37.1 ng/ml, 8.4-72.5 ng/ml, n=47). In contrast, the plasma levels of free transforming growth factor beta1 were greater in paracetamol overdose (623 pg/ml, 46.7-1241 pg/ml, n=21) than in non-A, non-B hepatitis (131 pg/ml, 77.2-254 pg/ml, n=9), with both being higher than control (72.3 pg/ml, 28.7-108, n=7, p<0.001). The plasma levels of human hepatocyte growth factor in patients with paracetamol overdose (7.04 ng/ml, 1.00-62.4 ng/ml) were significantly higher than those in patients with non-A, non-B hepatitis (4.48 ng/ml, 0.74-9.10 ng/ml, p<0.05). Northern blots showed increased mRNA expression of transforming growth factor-beta1 in paracetamol-overdose patients (n=8, p<0.05), but not in patients with non-A non-B hepatitis (n=6), compared to controls (n=4).

CONCLUSIONS

The increased circulating plasma TGF-beta1 in FHF may be part of the tissue repair process in fulminant hepatic failure. In patients with non-A, non-B hepatitis, the increased total transforming growth factor-beta1 together with a less elevated hepatocyte growth factor could be related to impaired liver regeneration in this group.

Expression of messenger RNA for liver functions following 70% and 90% hepatectomy

AIMS/METHODS

The effect of moderate and severe reduction of the functional liver mass on gene expression for liver functions was studied in rats following 70% and 90% hepatectomy. At intervals up to 24 h after operation rats were killed and RNA was extracted from the remaining liver tissue. By slot-blot hybridization mRNA steady-state levels were determined for enzymes involved in metabolic 'liver-specific' functions, acute phase proteins, 'house-keeping', and growth-related proteins. Results were expressed as per cent of levels in a pool from fed control rats of the same gender and age.

RESULTS

Among 'liver-specific' metabolic functions only expression of gluconeogenesis, represented by phosphoenol carboxykinase mRNA, was augmented initially, followed by a fall to very low values after 90% hepatectomy. The drug metabolizing system represented by CYP2B1/2 mRNA was reduced to half of the control values. Expression of urea synthesis, as reflected by carbamoylphosphate synthetase mRNA, showed a gradual decline after 90% hepatectomy, in contrast to rising levels of argininosuccinate lyase and arginase mRNA, possibly serving polyamine rather than urea synthesis. The mRNA level of the acute phase protein alpha 1-acid glycoprotein showed a smaller and later rise in 90% than in 70% hepatectomized rats, whereas that of alpha 2-macroglobulin only increased after 90% hepatectomy like the 'house-keeping' beta-actin mRNA. A rise in histone 3, which coincides with mitosis, was only seen after 70% hepatectomy, indicating that after 90% hepatectomy the response to growth-stimulating factors is weak or delayed, supported by a delayed rise in cyclin d and low levels of growth hormone receptor mRNA.

CONCLUSIONS

It is concluded that attempts by gene regulation to adapt liver functions to a reduction of the liver mass depend on the amount of liver tissue lost. When the loss is nearly fatal, compensation for normal metabolic functions may be abandoned for efforts to regenerate, which, however, may be delayed or after all be too weak.