Transforming growth factor-βeta and interleukin-1βeta in children with acute liver failure: pathophysiology and outcome perspectives

Background

The exact pathophysiology of acute liver failure (ALF) in children is not well defined. Some animal studies showed increased cytokines as a driving force for its occurrence with defective similar human studies. This study aimed to measure the plasma level of the pro-inflammatory cytokine (IL-1β) and anti-inflammatory cytokine (TGF-β) in children with ALF and assess their relation to the outcome and complications.

Patients and methods

It is a prospective case–control study that included 25 children with ALF, 20 children with self-limited acute hepatitis A, and 10 healthy children as control groups. Plasma samples were collected at presentation to measure IL-1β and TGF-β levels using the ELISA technique.

Results

Higher levels of IL-1β and TGF-β were found in ALF than acute hepatitis A group with insignificant differences. TGF-β was significantly higher in ALF and acute hepatitis groups than the healthy control group (p-value < 0.05). Moreover, the TGF-β/IL-1β ratio showed no significant difference among the studied groups despite trending to be higher in ALF. TGF-β and TGF-β/IL-1β ratio were higher in the survived while IL-1β was higher in the deceased cases but all did not reach a significant level. When the TGF-β/IL-1β ratio was ≥ .8, the survival probability in ALF cases was 100%. In the ALF group, IL-1β was significantly higher in those who were complicated with brain edema and circulatory failure (p-value < 0.05). A model score designed of TGF-β/IL-1β ratio, age, encephalopathy, and brain edema can predict mortality in ALF cases at a cutoff value of − 1.2 with a sensitivity of 100%.

Conclusion

Increased cytokines in ALF with an imbalance between the pro- and anti-inflammatory cytokines could have a role in the pathogenesis and the outcome of ALF. TGF-β/IL-1β ratio is trending to be higher in survived ALF cases and a model score including it can predict the mortality. The baseline level of IL-1β in ALF is significantly higher in those who develop brain edema and circulatory failure, so experimental studies of its targeting are warranted.

Managing a Prospective Liver Transplant Recipient on the Waiting List

The management of a patient in the peri-transplantation period is highly challenging, and it is even more difficult while the patient is on the transplantation waitlist. Keeping the patient alive during this period involves managing the complications of liver disease and preventing the disease's progression. Based on the pre-transplantation etiology and type of liver failure, there is a difference in the management protocol. The current review is divided into different sections, which include: the management of underlying cirrhosis and complications of portal hypertension, treatment and identification of infections, portal vein thrombosis management, and particular emphasis on the management of patients of hepatocellular carcinoma and acute liver failure in the transplantation waitlist. The review highlights special concerns in the management of patients in the Asian subcontinent also. The review also addresses the issue of delisting from the transplant waitlist to see that futility does not overtake the utility of organs. The treatment modalities are primarily expressed in tabular format for quick reference. The following review integrates the vast issues in this period concisely so that the management during this crucial period is taken care of in the best possible way.

The role of living donor liver transplantation for acute liver failure

Acute liver failure (ALF) is a life-threatening illness that occurs in the absence of pre-existing liver disease. When symptoms seriously progress under continuous supportive medical care, liver transplantation becomes the only therapeutic strategy. However, the available sources of organs for liver transplantation differ worldwide. In regions in which organs from cadaveric donors are more common, deceased donor liver transplantation (DDLT) is performed in this urgent situation. Conversely, in countries where cadaveric donors are scarce, living donor liver transplantation (LDLT) is the only choice. Special considerations must be made for urgent LDLT for ALF, including the expedited evaluation of living donors, technical issues, and the limitations of ABO blood type combinations between recipients and donor candidates. In this review, we highlight the role of LDLT for ALF and the considerations that distinguish it from DDLT. LDLT is well-established as a life-saving procedure for ALF patients and there is often no alternative to LDLT, especially in countries where DDLT is not feasible. However, from a global perspective, an increase in the deceased donor pool might be an urgent and important necessity.

EASL Clinical Practical Guidelines on the management of acute (fulminant) liver failure

The term acute liver failure (ALF) is frequently applied as a generic expression to describe patients presenting with or developing an acute episode of liver dysfunction. In the context of hepatological practice, however, ALF refers to a highly specific and rare syndrome, characterised by an acute abnormality of liver blood tests in an individual without underlying chronic liver disease. The disease process is associated with development of a coagulopathy of liver aetiology, and clinically apparent altered level of consciousness due to hepatic encephalopathy. Several important measures are immediately necessary when the patient presents for medical attention. These, as well as additional clinical procedures will be the subject of these clinical practice guidelines.

Plasma transforming growth factor β1, metalloproteinase-1 and tissue inhibitor of metalloproteinases-1 in acute viral hepatitis type B

AIM

Antiproliferative, pro-apoptotic and immunosuppressive activity effects suggest crucial role of transforming growth factor (TGF)-beta1, metalloproteinase (MMP)-1 and its tissue inhibitor (TIMP)-1 in the pathogenesis of acute liver injury that in some patients precede development of chronic liver diseases and fibrogenesis. The aim of this study was to evaluate effect of acute HBV infection on plasma TGF-beta1, MMP-1 and TIMP-1 levels.

METHODS

TGF-beta1, MMP-1 and TIMP-1 plasma concentrations were measured with an enzyme immunoassay in 39 patients with acute viral hepatitis type B. Baseline measurement was performed within the first week of jaundice and then weekly up to the fourth week of the disease. Results were compared to baseline and normal values and to liver function tests.

RESULTS

Plasma concentrations of TGF-beta1, TIMP-1 and MMP-1 were significantly elevated in the first week of acute viral B hepatitis in comparison to normal. Analysis of individual values demonstrated significant positive correlation between plasma concentrations of TGF-beta1 and TIMP-1. There was no correlation between MMP-1 and TGF-beta1 or TIMP-1. Significant correlation was demonstrated between both TGF-beta1 and ALT or AST as well as between TIMP-1 and ALT, AST or bilirubin. Elevated baseline levels of both TGF-beta1 and TIMP-1 decreased gradually in consecutive weeks of the disease. TGF-beta1 but not TIMP-1 plasma concentrations were significantly lower in 3rd and 4th week than baseline values. MMP-1 concentration remained on baseline level in the 2nd week of the disease. However in the 3rd week its values increased suddenly but the significant difference in comparison to baseline was observed only in 4th week.

CONCLUSIONS

These results indicate important role of TGF-beta1, TIMP-1 and MMP-1 in acute viral hepatitis, that seems to be connected first of all with hepatocytes damage. Their role in extracellular matrix metabolism during acute liver injury needs further evaluation.

Comparison of Plasma Exchange With Different Membrane Pore Sizes in the Treatment of Severe Viral Hepatitis

Plasma exchange has become an effective mode of blood purification in patients suffering from liver failure. To assist in patient recovery, we compared two plasma separators to identify a plasma separator with suitable pore sizes to remove toxic substances effectively, and retain important plasma components. The study focused on severe viral hepatitis patients. Of 206 rounds of plasma exchange, 137 were completed with the PS-06 plasma separator (membrane pore size=0.2 microm) and 69 with the EC-4A plasma separator (membrane pore size=0.03 microm). The efficacy of different plasma separators was compared using survival rate, changes in liver biochemistry, immunoglobulin, and complement parameters. The survival rate of patients treated with PS-06 was 43.3% (13 of 30 patients). For patients treated with EC-4A, two patients were bridged to liver transplantation successfully, and 57.9% (11 of 19 patients) survived. In both groups, the levels of total bilirubin, prothrombin time, and bile acid declined significantly. Compared to PS-06, EC-4A could retain significantly larger amounts of immunoglobulin and complements. Our study revealed that plasma exchange implementation with membrane pore size 0.03 microm could remove adequate bilirubin and bile acid, a class of toxins bound to plasma protein in severe viral hepatitis patients, and reduce the loss of essential plasma macromolecules.

Artificial and bioartificial support systems for liver failure

BACKGROUND

Artificial and bioartificial liver support systems may 'bridge' patients with acute or acute-on-chronic liver failure to liver transplantation or recovery.

OBJECTIVES

To evaluate beneficial and harmful effects of artificial and bioartificial support systems for acute and acute-on-chronic liver failure.

SEARCH STRATEGY

Trials were identified through The Cochrane Hepato-Biliary Group Controlled Trials Register (September 2002), The Cochrane Central Register of Controlled Trials on The Cochrane Library (Issue 3, 2002), MEDLINE (1966 - September 2002), EMBASE (1985 - September 2002), and The Chinese Biomedical Database (September 2002), manual searches of bibliographies and journals, authors of trials, and pharmaceutical companies.

SELECTION CRITERIA

Randomised clinical trials on artificial or bioartificial support systems for acute or acute on-chronic liver failure were included irrespective of blinding, publication status, or language. Non-randomised studies were included in explorative analyses.

DATA COLLECTION AND ANALYSIS

Data were extracted independently by three reviewers. Results were presented as relative risks (RR) with 95% confidence intervals (CI). Sources of heterogeneity were explored through sensitivity analyses and meta-regression. The primary outcome was mortality.

MAIN RESULTS

Twelve trials on artificial or bioartificial support systems versus standard medical therapy (483 patients) and two trials comparing different artificial support systems (105 patients) were included. Most trials had unclear methodological quality. Compared to standard medical therapy, support systems had no significant effect on mortality (RR 0.86; 95% CI 0.65-1.12) or bridging to liver transplantation (RR 0.87; 95% CI 0.73-1.05), but a significant beneficial effect on hepatic encephalopathy (RR 0.67; 95% CI 0.52-0.86). Meta-regression indicated that the effect of support systems depended on the type of liver failure (P = 0.03). In subgroup analyses, artificial support systems appeared to reduce mortality by 33% in acute-on-chronic liver failure (RR 0.67; 95% CI 0.51-0.90), but not in acute liver failure (RR 0.95; 95% CI 0.71-1.29). Two trials comparing artificial support systems showed significant mortality reductions with intermittent versus continuous haemofiltration (RR 0.58; 95% CI 0.36-0.94) and no significant difference between five versus ten hours of charcoal haemoperfusion (RR 1.03; 95% CI 0.65-1.62). The incidence of adverse events was inconsistently reported.

REVIEWER'S CONCLUSIONS

This Review indicates that artificial support systems may reduce mortality in acute-on-chronic liver failure. Artificial and bioartificial support systems did not appear to affect mortality in acute liver failure. However, considering the strength of the evidence additional randomised clinical trials are needed before any support system can be recommended for routine use.

Bioartificial liver support devices: historical perspectives

Fulminant hepatic failure (FHF) is an important cause of death worldwide. Despite significant improvements in critical care therapy there has been little impact on survival with mortality rates approaching 80%. In many patients the cause of the liver failure is reversible and if short-term hepatic support is provided, the liver may regenerate. Survivors recover full liver function and a normal life expectancy. For many years the only curative treatment for this condition has been liver transplantation, subjecting many patients to replacement of a potentially self-regenerating organ, with the lifetime danger of immunosuppression and its attendant complications, such as malignancy. Because of the shortage of livers available for transplantation, many patients die before a transplant can be performed, or are too ill for operation by the time a liver becomes available. Many patients with hepatic failure do not qualify for liver transplantation because of concomitant infection, metastatic cancer, active alcoholism or concurrent medical problems. The survival of patients excluded from liver transplantation or those with potentially reversible acute hepatitis might be improved with temporary artificial liver support. With a view to this, bioartificial liver support devices have been developed which replace the synthetic, metabolic and detoxification functions of the liver. Some such devices have been evaluated in clinical trials. During the last decade, improvements in bioengineering techniques have been used to refine the membranes and hepatocyte attachment systems used in these devices, in the hope of improving function. The present article reviews the history of liver support systems, the attendant problems encountered, and summarizes the main systems that are currently under evaluation.

Maintenance of integrity and function of isolated hepatocytes during extended suspension culture at 25 degrees C

Isolated hepatocytes in suspension provide a number of advantages for use in bioartificial liver device, however, poor stability of this cell preparation at physiological temperatures is an apparent barrier preventing their use. We therefore investigated the integrity and differentiated function of isolated rat hepatocytes under conditions of mild hypothermia. Isolated hepatocytes were suspended in a bicarbonate buffered saline medium, supplemented with glucose and bovine serum albumin (BSA), and maintained for 48 h at 25 degrees C on a rotary shaker under an atmosphere of 95% O2 and 5% CO2. Under these conditions there was no significant decline in cell viability and good preservation of cellular morphology on transmission electron microscopy for at least 24 h. Isolated hepatocytes in suspension at 25 degrees C were also able to maintain normal Na+ and K+ ion gradients. The cellular energy status ([ATP], ATP/ADP ratio, cytoplasmic and mitochondrial redox potentials), metabolic function (urea synthesis and ammonia removal), albumin synthesis and phase I and phase II drug detoxification activity of these cells were also maintained for at least 24 h post isolation. These observations demonstrate the robust nature of mildly hypothermic isolated hepatocytes in suspension and encourage further studies re-examining the feasibility of using this cell preparation in bioartificial livers.

Artificial and bioartificial support systems for liver failure: a Cochrane Hepato-Biliary Group Protocol

AIMS/BACKGROUND

Liver support systems may bridge patients to liver transplantation or recovery from liver failure. This review is to evaluate the beneficial and harmful effects of artificial and bioartificial support systems for acute and acute-on-chronic liver failure.

DATA SOURCES

Randomized trials on any support system versus standard medical therapy will be included irrespective of publication status or language. Non-randomized studies are included in explorative analyses. Trials will be identified through bibliographies, correspondence with original investigators, and electronic searches (Cochrane Hepato-Biliary Group Controlled Trials Register, Cochrane Controlled Trials Register, MEDLINE, EMBASE, and The Chinese Biomedical Database).

METHODS OF THE REVIEW

The extracted data will include characteristics of trials, patients, interventions, and all outcome measures. Methodological quality will be assessed by the randomization, follow up, and blinding. The RevMan and STATA will be used for statistical analyses. Sources of heterogeneity and methodological quality in the assessment of the primary outcome will be explored by sensitivity analyses and meta-regression.

Transforming growth factor-beta1 as a surrogate marker of hepatic dysfunction in chronic liver diseases

The aim of the study was to evaluate the possible association between plasma concentrations of transforming growth factor-beta1 (TGF-beta1) and the degree of hepatic dysfunction in patients with chronic liver diseases. TGF-beta1 was measured with an enzyme immunoassay in plasma from 21 patients with chronic active hepatitis and 40 patients with liver cirrhosis. Normal values were obtained from a group of 13 healthy volunteers. Results were analysed with respect to aetiology and the degree of liver insufficiency as evaluated by the Child-Pugh classification. The mean plasma concentration of TGF-beta1 in patients (36.9+/-2.8 ng/ml) was twice that found in normal volunteers (18.3+/-1.6 ng/ml). The highest values were observed in patients with alcoholic liver cirrhosis (44.4+/-4.7 ng/ml). Plasma TGF-beta1 showed a statistically significant positive correlation with the degree of liver insufficiency. These results indicate the possible use of plasma TGF-beta1 measurement as a good marker of liver function impairment. Further observation of patients involved in this study may help to evaluate its possible prognostic value in chronic liver diseases.

Circulating transforming growth factor beta(1) as an indicator of hepatic function impairment in liver cirrhosis

In the liver, transforming growth factor (TGF) -beta(1)is primarily responsible for activation of fat-storing cells, which are the main source of extracellular matrix proteins. Their deposition play a key role in the development of liver cirrhosis. The aim of this study was to evaluate plasma TGF-beta(1)in patients with different stages of liver cirrhosis and its possible use as an indicator of liver function impairment. TGF-beta(1)was measured in the plasma of 40 patients with liver cirrhosis. To estimate possible effect of liver insufficiency on plasma TGF-beta(1), patients were divided into three groups: A, B and C, univocal with Child-Pugh classes. Normal values were collected from 13 healthy volunteers. Liver cirrhosis resulted in a significant increase of plasma concentration of TGF-beta(1)(39.3+/-3.8 ng/ml), which doubled normal values (18.3+/-1.6 ng/ml). The highest concentrations were observed in alcoholic patients (44.4+/-4.7 ng/ml). TGF-beta(1)level increased depending on the degree of liver insufficiency, demonstrated by a significant positive correlation with Child-Pugh score (r=0.591). Values in group A were similar to normal, but were significantly elevated in groups B and C. These findings suggest possible use of plasma TGF-beta(1)measurement as an indicator of liver function impairment and possible marker of hepatic fibrosis progression in cirrhotic patients.