Fulminant hepatic failure

A modified surgical model of fulminant hepatic failure in the rat

BACKGROUND

There is a need for better animal models of fulminant liver failure (FHF). Eguchi et al described an interesting surgical model of FHF in the rat. This model includes 68% partial hepatectomy, ischemia of 24% of the liver mass, and 8% of remnant liver left intact. In the original description by Eguchi et al, rats were administered subcutaneous glucose. However, the authors found that normothermic FHF rats with subcutaneous glucose died from deep hypoglycemia. In this report, we describe a modification of that model, and show that administration of intravenous glucose allows better survival and development of intracranial hypertension.

METHODS

We operated on FHF rats using the procedure described by Eguchi et al, kept them normothermic, and maintained normoglycemia by continuous intravenous glucose injection (glucose 10%, 1 mL/h). At 24 h, we monitored liver blood tests (n = 5), intracranial pressure (n = 5), clinical encephalopathy, and survival (n = 10), and compared them with sham and 68% hepatectomy rats.

RESULTS

The FHF rats developed acute cytolysis, cholestasis, and liver failure, as demonstrated by the liver blood tests. They experienced progressive encephalopathy and intracranial hypertension leading to death. Mean survival was 45.9 h. Of 10 FHF rats from the survival evaluation cohort, one survived 7 d. Laparotomy showed necrosis of lateral liver lobes and enlargement of omental lobes with a normal hepatic aspect, suggesting liver recovery.

CONCLUSIONS

This surgical rat model mimics the features of human FHF and seems interesting for further research into the pathophysiology and therapeutic management of the disease.

Point-of-care continuous 13C-methacetin breath test improves decision making in acute liver disease: Results of a pilot clinical trial

AIM: To assess the role of the ¹³C-methacetin breath test (MBT) in patients with acute liver disease.

METHODS: Fifteen patients with severe acute liver disease from diverse etiologies were followed-up with ¹³C-MBT during the acute phase of their illnesses (range 3-116 d after treatment). Patients fasted for 8 h and ingested 75 mg of methacetin prior to the MBT. We compared results from standard clinical assessment, serum liver enzymes, synthetic function, and breath test scores.

RESULTS: Thirteen patients recovered and two patients died. In patients that recovered, MBT parameters improved in parallel with improvements in lab results. Evidence of consistent improvement began on day 3 for MBT parameters and between days 7 and 9 for blood tests. Later convergence to normality occurred at an average of 9 d for MBT parameters and from 13 to 28 d for blood tests. In both patients that died, MBT parameters remained low despite fluctuating laboratory values.

CONCLUSION: The ¹³C-MBT provides a rapid, non-invasive assessment of liver function in acute severe liver disease of diverse etiologies. The results of this pilot clinical trial suggest that the MBT may offer greater sensitivity than standard clinical tests for managing patients with severe acute liver disease.

Noninvasive monitoring of cerebral perfusion pressure in patients with acute liver failure using transcranial doppler ultrasonography

Elevated intracranial pressure (ICP) leads to loss of cerebral perfusion, cerebral herniation, and irreversible brain damage in patients with acute liver failure (ALF). Conventional techniques for monitoring ICP can be complicated by hemorrhage and infection. Transcranial doppler ultrasonography (TCD) is a noninvasive device which can continuously measure cerebral blood flow velocity, producing a velocity-time waveform that indirectly monitors changes in cerebral hemodynamics, including ICP. The primary goal of this study was to determine whether TCD waveform features could be used to differentiate ALF patients with respect to ICP or, equally important, cerebral perfusion pressure (CPP) levels. A retrospective study of 16 ALF subjects with simultaneous TCD, ICP, and CPP measurements yielded a total of 209 coupled ICP-CPP-TCD observations. The TCD waveforms were digitally scanned and seven points corresponding to a simplified linear waveform were identified. TCD waveform features including velocity, pulsatility index, resistive index, fraction of the cycle in systole, slopes, and angles associated with changes in the slope in each region, were calculated from the simplified waveform data. Paired ICP-TCD observations were divided into three groups (ICP < 20 mmHg, n = 102; 20 < or = ICP < 30 mmHg, n = 74; and ICP > or = 30 mmHg, n = 33). Paired CPP-TCD observations were also divided into three groups (CPP > or = 80 mmHg, n = 42; 80 > CPP > or = 60 mmHg, n = 111; and CPP < 60 mmHg, n = 56). Stepwise linear discriminant analysis was used to identify TCD waveform features that discriminate between ICP groups and CPP groups. Four primary features were found to discriminate between ICP groups: the blood velocity at the start of the Windkessel effect, the slope of the Windkessel upstroke, the angle between the end systolic downstroke and start diastolic upstroke, and the fraction of time spent in systole. Likewise, 4 features were found to discriminate between the CPP groups: the slope of the Windkessel upstroke, the slope of the Windkessel downstroke, the slope of the diastolic downstroke, and the angle between the end systolic downstroke and start diastolic upstroke. The TCD waveform captures the cerebral hemodynamic state and can be used to predict dynamic changes in ICP or CPP in patients with ALF. The mean TCD waveforms for corresponding, correctly classified ICP and CPP groups are remarkably similar. However, this approach to predicting intracranial hypertension and CPP needs to be further refined and developed before clinical application is feasible.

Proliferation of L02 human hepatocytes in tolerized genetically immunocompetent rats

AIM: To investigate whether human hepatocytes could proliferate after transplantation to normal immunocompetent rats treated with 2-acetaminofluorene or Retrorsine and partial hepatectomy.

METHODS: L02 hepatocyte-tolerant Sprague-Dawley rats were injected with Retrorsine, 2-acetaminofluorene or normal saline. L02 hepatocytes were then transplanted via the spleen. Human albumin and its mRNA, specific proliferating cell nuclear antigen (PCNA), L02 hepatocyte dynamic distribution, number density and area density of PCNA-positive cells in the liver were determined.

RESULTS: All the examined indicators were not significantly different between the rats treated with 2-acetaminofluorene and normal saline, which was not the case with rats treated with Retrorsine. A dynamic distribution of L02 hepatocytes in the rat liver was detected from wk 1 to mo 6 after transplantation in the Retrorsine group and from wk 1 to 10 in the 2-acetaminofluorene group. Human albumin and its mRNA were detected from wk 2 to mo 6 in the Retrorsine group and from wk 1 to 8 in the 2-acetaminofluorene group. Specific human PCNA was detected in the rat liver from wk 2 to mo 6 in the Retrorsine group and from wk 2 to 6 in the 2-acetaminofluorene group. Human albumin and its mRNA contents as well as the number of PCNA positive cells reached a peak at wk 4.

CONCLUSION: L02 human hepatocytes could not proliferate significiantly after transplantation to the normal, immunocompetent rats treated with 2-acetaminofluorene. L02 human hepatocytes can survive for 10 wk after transplantation and express human albumin for 8 wk. L02 human hepatocytes can proliferate and express human albumin for 6 mo after transplantation to the rats treated with Retrorsine. The chimeric L02 human hepatocytes, which then underwent transplantation into tolerant rats, were normal in morphogenesis, biochemistry and function.

Exogenous adenosine 5'-triphosphate does not improve survival in rats with acute liver failure

BACKGROUND

Acute liver failure is associated with a marked depletion of intrahepatic adenosine 5'-triphosphate (ATP), a compound required for the maintenance of hepatic function and enhanced hepatic regeneration.

AIM

The aim of this study was to test the safety and efficacy of exogenous ATP at various doses in a rat model of acute liver failure.

METHODS

Adult male Sprague-Dawley rates (n = 56) received an intraperitoneal dose (1.0 g/kg) of the potent hepatotoxin D: -galactosamine (D: -galN). Thereafter, rats were divided into groups that received saline (n = 18), low (n = 8), moderate (n = 18) or high (n = 12) doses of ATP for 7 days.

RESULTS

There was an inverse correlation between ATP dose and survival such that rats treated with low dose ATP had the highest survival rate (50%) compared to moderate (39%) and high (17%) dose treated groups. However, survival in all treated groups was similar (P = 0.085) to that of controls (45%). Liver biochemistry, regenerative activity and ATP levels were similar in the highest survival group (low dose ATP) versus controls.

CONCLUSION

These findings suggest that exogenous ATP does not improve and indeed at high doses may impair survival in rats with acute liver failure. Further studies involving a wider range of ATP doses and different routes and frequency of ATP administration are required to determine whether exogenous ATP has therapeutic value in the treatment of acute liver failure.

Suppression of immune-mediated liver injury after vaccination with attenuated pathogenic cells

Cell vaccination via immunization with attenuated pathogenic cells is an effective preventive method that has been successfully applied in several animal models of inflammatory or autoimmune diseases. Concanavalin A (Con A)-induced hepatitis (CIH) is a commonly used experimental model to study immune-mediated liver injury. Multiple cell types including T lymphocytes, macrophages and neutrophils have been found to be involved in the pathogenesis of CIH. In this study, we used attenuated spleen lymphocytes or peripheral blood lymphocytes as vaccines to investigate whether they could induce protective immune responses to prevent mice from developing CIH. We found that mice receiving such vaccination before CIH induction developed much milder diseases, exhibited a lower level of alanine aminotransferase (ALT) released into their plasma and had less inflammatory lesions in their livers. Such CIH-suppression is dose- and frequency-dependent. The suppressive effect was associated with inhibition of several major inflammatory mediators, pro-inflammatory cytokines and chemokines.

Global distribution of infectious diseases requiring intensive care

This article describes infectious diseases that are of special importance to intensivists. The emphasis on epidemiology notwithstanding, it also addresses clinical, diagnostic, and treatment issues related to each infection described. The discussion avoids terrorism-related aspects of these infections, because they were very well covered in the October 2005 issue of the Critical Care Clinics.

The effect of total plasma exchange on fulminant hepatic failure

Total plasma exchange (TPE) corrects coagulopathy in patients with liver disease and removes hepatotoxins/cytokines. This improvement is transient but can be used as a bridge until an organ is identified for liver transplantation (LTx) or the liver itself regenerates. Our aim was to retrospectively assess the efficacy of TPE in fulminant hepatic failure (FHF) and its impact on liver function tests. Between 1995-2001, 39 patients with FHF who had undergone TPE were reviewed. FHF was defined according to the O'Grady criteria based on the duration of encephalopathy as well as jaundice. TPE was performed using the Cobe Spectra TPE (Gambro) in Liver Intensive Care Unit, continued on a daily basis, until either adequate clinical response was achieved, the patient expired, or transplantation occurred. INR, PTT, Fibrinogen, ALT, AST, GGT, BUN, Ammonia, and Total Bilirubin were analyzed before and after TPE. Student's t-test and chi-square test and ANOVA were used for statistical analysis. Thirty-nine patients with FHF (31 females, 8 males with mean age of 32.3, range: 7-64) underwent TPE. Coagulopathy, hyperbilirubinemia, hyperammonemia were significantly improved (P < 0.05). Twenty-one patients survived (54%), 12 required LTx, and 18 patients (including one after LTx) expired. TPE was found to be significantly effective for correction of coagulopathy and improvement of liver tests. This intervention can be considered for temporary liver support until recovery or liver transplantation.

Intensive care unit management of fulminant hepatic failure

OBJECTIVE

The aim of this open/retrospective study was to evaluate the outcomes of intensive care unit patients treated for fulminant hepatic failure (FHF) for predictive indices.

METHODS

All patients were recovered in the intensive care units with a diagnosis of FHF. We considered three groups of patients: (1) survivors, deceased, and transplanted.

SUBJECTS

All patients were fully screened, including liver function indices such as AST, ALT, total and bound bilirubin, albumin and pre-albumin, factors 5 and 7, alpha fetal protein (alpha-PP), other coagulation tests (PT, aPTT, INR, ATIII), and renal function (BUN and creatinine) parameters. For each patient Apache II score was calculated upon admission to the intensive care unit.

RESULTS

Apache II score showed efficacy. alpha-PP increased in both surviving and deceased, but not in the transplanted group. After intensive care unit admission, AST and ALT peaks were higher in the deceased DP than in the transplanted group. The INR value at the third day after ICU admission improved in the survivors compared with the other two cohorts. Factor 5 levels were lower among patients undergoing transplantation, but increased in the other two groups. The prognosis was strictly dependent upon the development of renal failure.

CONCLUSION

The Apache II score was a sensitive predictive index for outcome. alpha-PP and factor 5 were not related to outcome, but useful for decision making when determining potential liver transplantation. INR can be used as a prognostic index. Intensive treatment beforehand is of primary importance to prevent multiple organ failure.

Portal vein thrombosis after intraportal hepatocytes transplantation in a liver transplant recipient

Hepatocytes transplantation is viewed as a possible alternative or as a bridge therapy to liver transplantation for patients affected by acute or chronic liver disorders. Very few data regarding complications of hepatocytes transplantation is available from the literature. Herein we report for the first time a case of portal vein thrombosis after intraportal hepatocytes transplantation in a liver transplant recipient. A patient affected by acute graft dysfunction, not eligible for retransplantation, underwent intraportal infusion of 2 billion viable cryopreserved ABO identical human allogenic hepatocytes over a period of 5 h. Hepatocytes were transplanted at a concentration of 14 million/ml for a total infused volume of 280 ml. Doppler portal vein ultrasound and intraportal pressure were monitored during cell infusion. The procedure was complicated, 8 h after termination, by the development of portal vein thrombosis with liver failure and death of the patient. Autopsy showed occlusive thrombosis of the intrahepatic portal vein branches; cells or large aggregates of epithelial elements (polyclonal CEA positive), suggestive for transplanted hepatocytes, were co-localized inside the thrombus.

CD154-CD40 interactions drive hepatocyte apoptosis in murine fulminant hepatitis

The CD154-CD40 interaction is a critical costimulatory pathway modulating the cellular immune response. Moreover, fulminant hepatitis of various etiologies is characterized by a hepatic influx of CD154-expressing T cells and an upregulation of CD40 expression on Kupffer cells and hepatocytes, implicating this pathway in the pathogenesis of fulminant hepatitis. In this study, we used a murine model of fulminant hepatitis induced by concanavalin A (con A) and documented a significant influx of CD154-expressing T cells into the livers of mice treated with con A, in association with markedly increased expression of CD40 restricted mainly to hepatocytes in damaged areas of the liver. Furthermore, con A hepatitis in CD154-deficient mice was significantly attenuated compared with that in wild-type controls and was associated with a decrease in hepatic tumor necrosis factor alpha (TNF-alpha) levels and hepatocyte death. We next determined the role of the CD154-CD40 pathway in hepatocyte death in vitro. These in vitro studies demonstrated that TNF-alpha induces CD40 expression in hepatocytes and that subsequent activation of CD40 results in hepatocyte apoptosis mediated at least in part by enhanced hepatocyte expression of FasL. In conclusion, CD154 stimulation of CD40 plays a central role in hepatocyte death in fulminant hepatitis through direct and indirect pathways that may have direct therapeutic implications in humans. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).

Combined human growth hormone and lactulose for prevention and treatment of multiple organ dysfunction in patients with severe chronic hepatitis B

AIM: To evaluate the efficiency and safety of combined recombinant human growth hormone (rhGH) and lactulose for treatment and/or prevention of multiple organ dysfunction in patients with chronic severe hepatitis B.

METHODS: Forty-eight inpatients with chronic severe hepatitis B were randomly divided into rhGH group (n = 28) and control group (n = 20). In rhGH group, 4-4.5 IU of rhGH was injected intramuscularly once daily for 2-4 wk, and 100 mL of enema containing 30 mL of lactulose, 2 g of metronidazole and 0.9% saline was administered every 2 d for 2-4 wk. Their symptoms and complications were noted. Liver and kidney functions were analyzed by an Olympus analyzer. Serum GH, IGF-1, IGFBP1 and IGFBP3 were measured by ELISA.

RESULTS: Clinical symptoms of 90% of these patients in rhGH group were obviously improved. The total effectiveness in rhGH group was better than that in control group (75% vs 40%, P<0.05). After 2- and 4-wk treatment of rhGH respectively, serum albumin (26.1±4.1 vs 30.2±5.3, 31.9±5.1 g/L), prealbumin (79.6±28.0 vs 106.6±54.4, 108.4±55.0 g/L), cholesterol (76.3±16.7 vs 85.6±32.3, 96.1±38.7 mg/dL), and IGFBP1 (56.8±47.2 vs 89.7±50.3 ng/mL after 2 wk) were significantly increased compared to control group (P<0.05). However, serum GH was decreased. The increase of serum IGF1 and IGFBP3 after rhGH treatment was also observed.

CONCLUSION: rhGH in combination with lactulose may be beneficial to the prevention and treatment of multiple organ dysfunction in patients with chronic severe hepatitis.

Establishment of Highly Differentiated Immortalized Human Hepatocyte Line With Simian Virus 40 Large Tumor Antigen for Liver Based Cell Therapy

Acute liver failure and metabolic liver disorder animal models have demonstrated that hepatocytes transplanted into the liver or spleen survive and participate in the liver repopulation process, and recent studies have documented the usefulness of hepatocyte transplantation in humans. However, despite the promising cell therapy, there are still many restrictions, such as the shortage of donor human livers and the limited lifespan and the functional insufficiency of primary cultured hepatocytes. The immortalized and highly differentiated human hepatocyte could provide an unlimited supply of transplantable cells. In this study, we established an efficient and highly differentiated immortalized human hepatocyte line for bioartificial liver and hepatocyte transplantation research. Hepatocytes isolated from the liver of a 25 year old, brain dead male were transfected with pcDNA3.1 (-) recombinant plasmid containing the genes encoding simian virus 40 (SV40) large tumor antigen. One of the hepatocyte clones, HepLL, displayed highly differentiated liver functions with immortalized characteristics and was selected with a 700-300 microg/ml of G418 technique in 42 days. To characterize this immortalized cell line for cell therapy in the near future, HepLL cells were studied with immunohistochemistry, reverse transcription-polymerase chain reactions, immunoblotting, and tumorigenicity tests. The results revealed that HepLL cells displayed morphologic characteristics of liver parenchymal cells, secreted albumin, synthesized urea and glycogen, and expressed liver enriched functional markers, but there were no tumorigenic qualities after transplantation into severe combined immunodeficiency mice. Thus this immortalized human hepatocyte line is expected to be a useful tool for studying the functions of differentiated human hepatocyte and a promising strategy to resolve the shortages of donor organs and the limits of primary human hepatocyte for transplantation and bioartificial liver support systems.

Acute Liver Failure

Acute liver failure (ALF) is an uncommon medical emergency whose rapid progression and high mortality demand early diagnosis and expert management, including immediate transfer of any potential case to facilities for intensive care and orthotopic liver transplantation (OLT). All patients with ALF must be screened aggressively for acetaminophen toxicity (history, serum levels, "hyperacute" presentation with renal failure), for other drugs, and viral hepatitis; rare causes of ALF should also be considered. After an acetaminophen overdose, N-acetylcysteine must be given as early as possible, preferably in the emergency room, but any patient with ALF should promptly receive N-acetylcysteine if there is suspicion of acetaminophen toxicity irrespective of the time of ingestion. Supportive care for all patients with ALF includes adequate enteral nutrition, aggressive screening and treatment of infection, prophylactic broad-spectrum antibiotics, and antifungal agents. Sedation with propofol is given for severe agitation or mechanical ventilation. With advanced coma grades, intensive care is needed with hemodynamic monitoring, ventilatory support, continuous renal replacement for renal failure, and intracranial pressure monitoring. Intracranial hypertension is treated with mannitol and/or acute short-term hyperventilation, but if the patient is refractory to treatment, mild-moderate hypothermia is achieved by a cooling blanket that is continued throughout OLT. Barbiturate coma is only used in refractory cases as the last treatment modality. Seizures are aggressively treated with phenytoin, with additional diazepam as needed. Candidacy and activation for OLT should be completed as early as possible in the course of ALF, especially in "hyperacute" cases such as acetaminophen toxicity. The final decision to proceed with OLT is made when a donor organ becomes available. King's College Hospital criteria for OLT are still the best prognostic assessment for fatal outcome in ALF, but the criteria fail to identify some patients who will die.

Effect on function of rat hepatocytes cultured with bone marrow cells

AIM: To study of the effect on the function of rat hepatocytes cultured with bone marrow cells.

METHODS: Rat hepatocytes were isolated by the modified two-step method described by Seglen. The primary cultured hepatocytes and bone marrow cells were served as cocultured group, and single cultured hepatocytes as control group. The yield and viability were assessed by trypan blue exclusion. The morphologic changes of cultured hepatocytes were observed. The concentrations of albumin and urea in the supernatant in different cultural period were examined.

RESULTS: The albumin synthesis (13.75 > 2.179, P < 0.05) and urea level (7.27 > 2.179, P < 0.05) had fluctuating changes in one week, and cocultured group had higher albumin synthesis and urea level.

CONCLUSION: Cocultured hepatocytes with bone marrow cells can improve the function of hepatocytes.