Long-Term Postoperative Bleeding After Dentoalveolar Surgery in the Pretransplant Liver Failure Patient

PURPOSE

A retrospective review of a protocol-driven single institutional experience for treatment of pretransplant liver failure patients requiring dentoalveolar procedures for transplant clearance.

MATERIALS AND METHODS

Between January 2003 and June 2005, 30 liver failure patients requiring pretransplant dentoalveolar surgery at the University of Michigan Hospital were treated in the Department of Oral and Maxillofacial Surgery/Hospital Dentistry undergoing 35 total procedures. These patients were stratified preoperatively into 3 different "risk" groups (minimal, moderate, high) based on number and complexity of teeth to be extracted as well as any planned adjunctive preprosthetic procedures.

RESULTS

Analysis of variance (ANOVA) comparison of groups was conducted, as well as logistic regression analysis and 2-tailed Pearson correlation using chi2 and the Fisher exact test. The only statistically significant (P < .05) predictors of long-term postoperative bleeding were surgeon-defined "risk," the number of simple extractions, and quadrants of alveoplasty. Additional postoperative correlations were found between long-term bleeding and the need for hospital admission as well as the use of blood products for treatment. Model for end-stage liver disease (MELD), preoperative prothombin time (PT), preoperative partial thromboplastin time (PTT), preoperative international normalized ratio (INR), and preoperative platelet count were not statistically significant in predicting postoperative bleeding. Despite a more aggressive protocol for preoperative management of "high risk" patients, 5/10 (50%) experienced prolonged postoperative bleeding, with 3/5 (60%) requiring admission, while 1/5 (20%) experienced significant prolongation of their current inpatient stay. Review of the data showed that 5/9 (56%) of patients with 10 or more simple extractions developed long-term postoperative bleeding, all of whom had been classified in the "high risk" grouping. Admitted patients remained hospitalized an average of 4 days (range of 1-6 days).

CONCLUSION

Even with aggressive preoperative management, pretransplant liver failure patients requiring extraction of at least 10 teeth prior to placement on the liver transplant list are at significant risk of long-term postoperative bleeding and hospital admission for its management.

The activin axis in liver biology and disease

Activins are a closely related subgroup within the TGFbeta superfamily of growth and differentiation factors. They consist of two disulfide-linked beta subunits. Four mammalian activin beta subunits termed beta(A), beta(B), beta(C), and beta(E), respectively, have been identified. Activin A, the homodimer of two beta(A) subunits, has important regulatory functions in reproductive biology, embryonic development, inflammation, and tissue repair. Several intra- and extracellular antagonists, including the activin-binding proteins follistatin and follistatin-related protein, serve to fine-tune activin A activity. In the liver there is compelling evidence that activin A is involved in the regulation of cell number by inhibition of hepatocyte replication and induction of apoptosis. In addition, activin A stimulates extracellular matrix production in hepatic stellate cells and tubulogenesis of sinusoidal endothelial cells, and thus contributes to restoration of tissue architecture during liver regeneration. Accumulating evidence from animal models and from patient data suggests that deregulation of activin A signaling contributes to pathologic conditions such as hepatic inflammation and fibrosis, acute liver failure, and development of liver cancer. Increased production of activin A was suggested to be a contributing factor to impaired hepatocyte regeneration in acute liver failure and to overproduction of extracellular matrix in liver fibrosis. Recent evidence suggests that escape of (pre)neoplastic hepatocytes from growth control by activin A through overexpression of follistatin and reduced activin production contributes to hepatocarcinogenesis. The role of the activin subunits beta(C) and beta(E), which are both highly expressed in hepatocytes, is still quite incompletely understood. Down-regulation in liver tumors and a growth inhibitory function similar to that of beta(A) has been shown for beta(E). Contradictory results with regard to cell proliferation have been reported for beta(C). The profound involvement of the activin axis in liver biology and in the pathogenesis of severe hepatic diseases suggests activin as potential target for therapeutic interventions.

Recovery from liver failure after hepatectomy for hepatocellular carcinoma in cirrhosis: meaning of the model for end-stage liver disease

BACKGROUND

Hepatectomy for hepatocellular carcinoma in cirrhosis is followed by an impairment of liver function that can lead to patient death. The model for end-stage liver disease (MELD) is considered an index of hepatic functional reserve, and its assessment on postoperative course may properly identify individuals at risk of liver failure.

STUDY DESIGN

Two hundred hepatectomies for hepatocellular carcinoma in cirrhosis were reviewed. Irreversible postoperative liver failure was defined as an impairment of liver function after hepatectomy that led to patient death or required transplantation. The MELD scores at postoperative days (POD) 1, 3, 5, and 7 were calculated and kinetics of changes investigated with t-test; logistic regression was applied to identify predictive variables of postoperative liver failure.

RESULTS

Kinetics of postoperative MELD score showed an impairment of liver function between PODs 1 and 3; 185 patients in whom postoperative liver failure did not develop showed a considerable decrease in MELD score between PODs 3 and 5 (11.9+/-2.8 and 10.6+/-2.4, respectively, p<0.001). On the contrary, 15 patients, who experienced the event, showed an increase in MELD score between PODs 3 and 5 (18.2+/-3.9 and 18.3+/-3.6, respectively; p=0.845). Multivariate analysis showed preoperative MELD score (p<0.001), major hepatectomy (p=0.028), and MELD score increase between PODs 3 and 5 (p=0.011) as independent predictors of irreversible postoperative liver failure. Scores are reported as mean+/-SD.

CONCLUSIONS

Recovery from liver impairment after hepatectomy for hepatocellular carcinoma in cirrhosis starts from POD 3; MELD scores increasing between PODs 3 and 5 may identify patients at risk of liver failure and represents the trigger for beginning intensive treatment or evaluating salvage transplantation.

Abdominal hypertension and liver dysfunction in intensive care unit patients: an "on-off" phenomenon?

Intra-abdominal hypertension (IAH) can affect liver hemodynamics but it is not known if has a significant clinical impact on liver function. The aim of this study was to investigate the relationship between IAH and liver function. A prospective study was performed in 110 adult intensive care unit (ICU) patients. Intra-abdominal pressure (IAP) was measured on admission and every other day, and liver sequential organ failure assessment (SOFA) score was collected whenever IAP was measured. IAH was defined by a IAP >or= 10 mm Hg, and liver dysfunction was defined by a hepatic SOFA score >or= 2. An overall IAH incidence of 56.3% was found (n = 62). Thirty-three patients presented a liver SOFA score >or= 2, with an overall incidence of 30%. Liver SOFA score of the group of patients with abdominal hypertension was higher than in group of patients without abdominal hypertension. (0.8 +/- 1.05 vs 0.4 +/- 0.7; P < .05), but IAH and liver dysfunction were not significantly associated (chi2 = 2.03; P = .15). When the whole sample was divided according to the worst IAP score (IAP < 10, IAP between 10 and 15, and IAP > 15), the corresponding liver dysfunction scores in the three groups were 0.35 +/- 0.6, 0.74 +/- 1, and 1.2 +/- 1.3, respectively (P = .01). A strict association between IAH and liver dysfunction was not found. Most likely, low levels of IAH, although able to reduce liver blood flow, are not per se sufficient to produce a real dysfunction; however, a correlation between the degree of IAH and the degree of hyperbilirubinemia exists. IAH does not seem to be an "on-off" phenomenon, but produces liver alterations for increasing levels of its severity.

The brain glutamate system in liver failure

Liver failure results in significant alterations of the brain glutamate system. Ammonia and the astrocyte play major roles in such alterations, which affect several components of the brain glutamate system, namely its synthesis, intercellular transport (uptake and release), and function. In addition to the neurological symptoms of hepatic encephalopathy, modified glutamatergic regulation may contribute to other cerebral complications of liver failure, such as brain edema, intracranial hypertension and changes in cerebral blood flow. A better understanding of the cause and precise nature of the alterations of the brain glutamate system in liver failure could lead to new therapeutic avenues for the cerebral complications of liver disease.

Growth after organ transplantation

Growth is an important feature of childhood, but it is usually impaired before and after organ transplantation. Modest catch-up growth often occurs after renal transplantation. Nevertheless, patients remain short due to the effects of steroids used for immunosuppression. Children with chronic liver failure are also growth impaired, although not to the same extent. They also frequently have poor catch up growth after transplantation, again due to steroids. There are several randomized controlled clinical trials reporting growth hormone (GH) use after renal transplantation. These consistently show a beneficial effect of GH on linear growth. Patients with histories of frequent acute rejections before GH may have increased risk of acute rejection during treatment. Few data exist on liver transplant patients, although GH also appears effective. GH use may be safe and effective for renal transplant recipients who have been stable without acute rejection episodes. There needs to be long-term study of GH use in liver and renal transplant patients. It is critical to focus efforts on improving growth in renal failure before transplantation through GH use and to improve posttransplant growth in all recipients by minimizing steroid exposure.

Ursodeoxycholic acid treatment of vanishing bile duct syndromes

Vanishing bile duct syndromes (VBDS) are characterized by progressive loss of small intrahepatic ducts caused by a variety of different diseases leading to chronic cholestasis, cirrhosis, and premature death from liver failure. The majority of adult patients with VBDS suffer from primary biliary cirrhosis (PBC) and primary sclerosing cholangitis (PSC). Ursodeoxycholic acid (UDCA), a hydrophilic dihydroxy bile acid, is the only drug currently approved for the treatment of patients with PBC, and anticholestatic effects have been reported for several other cholestatic syndromes. Several potential mechanisms of action of UDCA have been proposed including stimulation of hepatobiliary secretion, inhibition of apoptosis and protection of cholangiocytes against toxic effects of hydrophobic bile acids.

Acute and concomitant deterioration of hyponatremia and renal dysfunction associated with heart and liver failure

BACKGROUND

Although hyponatremia with concomitant renal dysfunction has been described anecdotally, little is known about how these two conditions are related, which type of renal dysfunction usually occurs, and which patients are at risk.

METHODS

From 3029 measured serum sodium (S(Na)) concentrations in 3 months, patients with at least one S(Na) < or =125 mmol/l were selected, and divided in patients with at least 1 S(Creat) > or =125 micromol/l (study group, n=20), and patients whose S(Creat) remained normal (control group, n=50).

RESULTS

During the first 5 days of hospitalization, S(Creat) almost doubled in the study group from 125 +/- 40 micromol/l to 207 +/- 72 micromol/l, while S(Na) decreased concurrently from 130 +/- 2 mmol/l to 122 +/- 3 mmol/l. The peak S(Creat) and S(Na) values coincided, and the average courses were highly correlated (r = 0.88, p < 0.001). The study group more often had heart failure (10/20 vs. 1/50, p < 0.001) and liver failure (7/20 vs. 4/50, p = 0.009), and received more often loop diuretics (13/20 vs. 12/50, p = 0.002), spironolactone (11/20 vs. 7/50, p = 0.001), and/or angiotensin-converting enzyme inhibitors (5/20 vs. 2/50, p = 0.02). Four patients were admitted to the intensive care (10 in control group, p = 1.0), and 5 patients died (10 in control group, p = 0.7).

CONCLUSIONS

Renal dysfunction is common in severe hyponatremia and usually develops in an acute-on-chronic fashion with concomitant deterioration of both conditions. This concourse is associated with heart failure, liver failure, and/or a renal drug regimen. Given the recent results of clinical trials, this patient group may be especially suitable for treatment with vasopressin antagonists.

Incorporating biological natural history in simulation models: empirical estimates of the progression of end-stage liver disease

OBJECTIVE

To develop an empiric natural-history model that can predict quantitative changes in the laboratory values and clinical characteristics of patients with end-stage liver disease (ESLD), to be used to calibrate an individual microsimulation model.

METHODS

The authors report the development of a stochastic model that uses cubic splines to interpolate between observed laboratory values over time in a cohort of 1997 patients with ESLD awaiting liver transplantation at the University of Pittsburgh Medical Center. The splines were recursively sampled to provide a stochastic, quantitative natural history of each candidate's disease.

RESULTS

The model was able to simulate the types of erratic disease trajectories that occur in individual patients and was able to preserve the statistical properties of the natural history of ESLD in cohorts of real patients. Moreover, the model was able to predict pretransplant survival rates (87% at 1 year), which were statistically similar to rates observed in the authors' local cohort (92%).

CONCLUSIONS

Cubic splines can be used to generate quantitative natural histories for individual patients with ESLD and may be useful for developing clinically robust microsimulation models of other diseases.

High rates of progressive hepatic functional deterioration whether lamivudine therapy is continued or discontinued after emergence of a lamivudine-resistant mutant: a prospective randomized controlled study

BACKGROUND

The management of patients with lamivudine-resistant mutants remains challenging, and no clear evidence has been presented concerning the discontinuation of lamivudine.

METHODS

Seventy-four patients with lamivudine-resistant mutants were prospectively enrolled and randomized; 37 patients continued (group A) and 37 patients discontinued lamivudine therapy (group B). The median follow-up was 20 months.

RESULTS

Serum albumin levels were reduced and prothrombin time was prolonged in both groups versus baseline (P = 0.015 and 0.045, respectively). Four patients in group A (10.8%) and six in group B (16.2%) experienced hepatitis flare, but the difference was not significant (P > 0.05). Multivariate analyses identified a younger age as a risk factor for hepatitis flare (P = 0.021). Seven (18.9%) decompensations occurred in group A and five (13.5%) in group B, which was not a significant difference (P > 0.05). Multivariate analyses revealed higher alanine aminotransferase and a lower platelet count as risk factors for hepatic decompensation (P = 0.001 and 0.001, respectively). The patients whose platelet count was <65 000/microl experienced hepatic decompensations more frequently (50%) than those with platelet counts >65 000/microl (13.2%) during follow-up (P = 0.05).

CONCLUSIONS

The clinical course of group B was not significantly different from that of group A. Therefore, the discontinuation of lamivudine may be a feasible option when other antiviral agents active against lamivudine-resistant mutants are unavailable.

Role of extracellular cGMP and of hyperammonemia in the impairment of learning in rats with chronic hepatic failure. Therapeutic implications

Hepatic encephalopathy is a complex neuropsychiatric syndrome present in patients with chronic or acute liver disease. We review here some recent advances in the study, in animal models, of the mechanisms involved in the impairment in intellectual function in hepatic encephalopathy. These studies show that the function of the glutamate-nitric oxide-cGMP pathway is impaired in brain in vivo in rats with chronic hyperammonemia or liver failure and from patients died in hepatic encephalopathy. This impairment leads to a reduced extracellular concentration of cGMP in the cerebellum and is associated with reduced learning ability in these animal models. Moreover, learning ability of hyperammonemic rats was restored by increasing cGMP by: (1) continuous intracerebral administration of zaprinast, an inhibitor of the cGMP-degrading phosphodiesterase, (2) chronic oral administration of sildenafil, an inhibitor of the phosphodiesterase that crosses the blood-brain barrier and (3) continuous intracerebral administration of cGMP. The data summarized indicate that impairment of learning ability in rats with chronic liver failure or hyperammonemia is due to impairment of the glutamate-nitric oxide-cGMP pathway. Moreover, increasing extracellular cGMP by pharmacological means may be a new therapeutic approach to improve cognitive function in patients with hepatic encephalopathy.

Platelet Recruitment in the Murine Hepatic Microvasculature During Experimental Sepsis: Role of Neutrophils

OBJECTIVES

Sepsis is a major clinical problem that often results in the dysfunction or failure of multiple organs, including the liver. While inflammatory cell activation has been implicated as an early critical event in sepsis-induced liver dysfunction, there is growing evidence for the involvement of activated platelets in this pathologic process.

METHODS

Intravital microscopy was used in this study to assess the magnitude and time course of platelet adhesion in the liver microcirculation during experimental sepsis and to determine whether the platelet accumulation is linked to leukocyte infiltration. The adhesion of platelets and leukocytes in terminal hepatic venules (THV) and sinusoids was quantified at 2, 4, and 6 h after abdominal sepsis induced by cecal ligation and puncture (CLP).

RESULTS

While the rolling and firm adhesion of platelets and leukocytes in THV were not altered in the first 2 h after CLP, platelet recruitment was observed at 4 h and further elevated at 6 h after CLP. Leukocyte adhesion in THV exhibited a similar time course. A similar accumulation of blood cells in sinusoids was noted after CLP. This was accompanied by an increased number of nonperfused sinusoids. CLP-induced leukocyte and platelet recruitment in THV and sinusoids was attenuated in mice rendered neutropenic with anti-neutrophil serum.

CONCLUSION

These findings indicate that sepsis is associated with a neutrophil-dependent recruitment of platelets in the liver microcirculation that impairs sinusoidal perfusion and may contribute to the liver dysfunction associated with sepsis.

Protective antibody levels and dose requirements for IV 5% Nabi Hepatitis B immune globulin combined with lamivudine in liver transplantation for hepatitis B-induced end stage liver disease

Lamivudine combined with Hepatitis B immune globulin (HBIg) prevents post liver transplant (LT) HBV recurrence. The study was designed to assess the impact of lamivudine on hepatitis B antibody (anti-HBs) and dosage requirements of intravenous 5% HBIg (Nabi-HB) in the first 36 weeks post LT. Adults undergoing LT for chronic HBV received lamivudine prior to or at LT, and IV HBIg 20,000 IU on day of LT, 10,000 on days 1-7, weeks 4 and 8, and 5,000 every 4 weeks thereafter. Replicative status based on serum HBV DNA (> 5 pg/mL = replicator (R) or < or = 5 pg/mL = nonreplicator (N) was determined at initiation of lamivudine (R or N) and within 2 weeks of LT (r or n), resulting in 3 groups: Nn, Rn, and Rr. Between December 1999 and May 2001, 30 patients (10 Nn, 13 Rn, 6 Rr, and 1 unknown), mean age of 52 years underwent LT. HBsAg neutralization was achieved with anti-HBs > 300 IU/L during week 1 and > 200 IU/L during weeks 2-12. All but one patient were HBsAg-negative on last follow-up. Pre-LT suppression of HBV replication resulted in similar dose requirements and pK in the Rn and Nn groups within 1 week after LT. Comparatively, the Rr group had greater HBIg requirements during weeks 1-12 due to greater anti-HBs clearance and shortened t(1/2) during the entire 36-week follow-up. In conclusion, this study provides a rationale for the use of lower HBIg doses in HBV patients with suppressed replication undergoing LT.

Protein-tyrosine Phosphatase 1B Deficiency Protects against Fas-induced Hepatic Failure

Genetic disruption of protein-tyrosine phosphatase 1B (PTP1B) in mice leads to increased insulin sensitivity and resistance to weight gain. Although PTP1B has been implicated as a regulator of multiple signals, its function in other physiological responses in vivo is poorly understood. Here we demonstrate that PTP1B-null mice are resistant to Fas-induced liver damage and lethality, as evident by reduced hepatic apoptosis in PTP1B-null versus wild type mice and reduced levels of circulating liver enzymes. Activation of pro-apoptotic caspases-8, -9, -3, and -6 was attenuated in livers from PTP1B-null mice following Fas receptor stimulation, although components of the death-inducing signaling complex were intact. Activation of anti-apoptotic regulators, such as the hepatocyte growth factor/Met receptor tyrosine kinase, as well as Raf, ERK1/2, FLIP(L), and the NF-kappaB pathway, was elevated in response to Fas activation in livers from PTP1B-null mice. Using PTP1B-deficient primary hepatocytes, we show that resistance to Fas-mediated apoptosis is cell autonomous and that signals involving the Met, ERK1/2, and NF-kappaB pathways are required for cytoprotection. This study identifies a previously unknown physiological role for PTP1B in Fas-mediated liver damage and points to PTP1B as a potential therapeutic target against hepatotoxic agents.

Proposal of a modified Child-Turcotte-Pugh scoring system and comparison with the model for end-stage liver disease for outcome prediction in patients with cirrhosis

The model for end-stage liver disease (MELD) has a better predictive accuracy for survival than the Child-Turcotte-Pugh (CTP) system and has been the primary reference for organ allocation in liver transplantation. The CTP system, with a score range of 5-15, has a ceiling effect that may compromise its predictive power. In this study, we proposed a refined CTP scoring method and investigated its predictive ability. An additional point was given to patients with serum albumin < 2.3 g/dL, bilirubin > 8 mg/dL or prothrombin time prolongation > 11 seconds. The modified CTP system, containing class D, was compared to the MELD and original CTP system in 436 patients. There was a significant correlation between the MELD and modified CTP score (rho = 0.59, P< 0.001). Using mortality as the endpoint, the area under receiver operating characteristic curve for modified CTP system was 0.895 compared with 0.872 for MELD (P = 0.450) and 0.809 for original CTP system (P < 0.001) at 3 months; the area was 0.890, 0.837 and 0.756, respectively (P = 0.051 and < 0.001, respectively) at 6 months. The risk ratio per unit increase for the modified CTP score was 2.7 and 3.08 at 3 and 6 months respectively (P < 0.001). In conclusion, the modified CTP system can be proposed as an alternative prognostic model for cirrhotic patients. By extending the score range according to the influence of the laboratory-derived variables, the modified CTP system has a better performance than the original system and is as efficient as the MELD for outcome prediction.

Influence of hepatic venous pressure gradient on the prediction of survival of patients with cirrhosis in the MELD Era

Measurements of portal pressure, usually obtained via the hepatic venous pressure gradient (HVPG) may be a prognostic marker in cirrhosis. The aim of this study was to evaluate the impact of HVPG on survival in patients with cirrhosis in addition to the Model for End-Stage Liver Disease (MELD) score. We also examined whether inclusion of HVPG in a model with MELD variables improves its prognostic ability. Retrospective analyses of all patients who had HVPG measurements between January 1998 and December 2002 were considered. Proportional hazards Cox models were developed. Prognostic calibrative and discriminative ability of the model was evaluated. In this period, 693 patients had a hepatic hemodynamic study, and 393 patients were included. Survival was significantly worse in those patients with greater HVPG value (univariate HR, 1.05; 95% CI, 1.02-1.08; P = .001). HVPG remained as an independent variable in a model adjusted by MELD, ascites, encephalopathy, and age (multivariate HR, 1.03; 95% CI, 1.00-1.06; P = .05) so that each 1-mmHg increase in HVPG had a 3% increase in death risk. In addition, HVPG as well as MELD score variables and age, significantly contributes to the calibrative predictive capacity of the prognostic model; however, discriminative ability improved only slightly (overall C statistic [95% CI]; MELD score variables: 0.71 [0.62-0.80], MELD score variables, age, and HVPG 0.76: [0.69-0.83]). In conclusion, HVPG has an independent effect on survival in addition to the MELD score. Although inclusion of HVPG and age in a survival predicting model would improve the calibrative ability of MELD, its discriminative ability is not significantly improved.

Reviews: The Current State of Nonuremic Applications for Extracorporeal Blood Purification

Despite the commonly accepted indications for hemodialysis and extracorporeal depuritive techniques, some clinicians have come to rely on blood purification for clinical states where the targeted substance for removal differs from uremic waste products. Over the last decade, a number of studies have emerged to help define the application of extracorporeal blood purification (ECBP) to these "nonuremic" indications. This review describes the application of extracorporeal blood purification in clinical states including sepsis, rhabdomyolysis, congestive heart failure, hepatic failure, tumor lysis syndrome, adult respiratory distress syndrome, intravenous contrast exposure, and lactic acidosis. Additional comments are provided to review existing literature on thermoregulation and osmoregulation, including acute brain injury.

Treatment of hepatitis C in patients who have decompensated cirrhosis

In 1999, the World Health Organization reported that there were 169.7 million cases of hepatitis C virus (HCV) infection worldwide. There are 212,500 Americans with chronic hepatitis C and cirrhosis, and this number will increase to 375,000 by the year 2015. If one applies the United States rates for proportion of HCV RNA positivity, duration of infection, and time required for development of cirrhosis to the world's population of individuals with HCV, then 7.8 million currently have cirrhosis. By 2015, there will be 13.8 million cases of cirrhosis due to HCV. Management of cirrhosis due to hepatitis C will continue to be a major issue for the foreseeable future for hepatologists, gastroenterologists, and primary care providers throughout the world. This article discusses the current status of antiviral strategies in treating patients who have decompensated chronic hepatitis C before transplantation.

Deficiency of PDK1 in liver results in glucose intolerance, impairment of insulin-regulated gene expression and liver failure

The liver plays an important role in insulin-regulated glucose homoeostasis. To study the function of the PDK1 (3-phosphoinositide-dependent protein kinase-1) signalling pathway in mediating insulin's actions in the liver, we employed CRE recombinase/loxP technology to generate L(liver)-PDK1-/- mice, which lack expression of PDK1 in hepatocytes and in which insulin failed to induce activation of PKB in liver. The L-PDK1-/- mice were not insulin-intolerant, possessed normal levels of blood glucose and insulin under normal feeding conditions, but were markedly glucose-intolerant when injected with glucose. The L-PDK1-/- mice also possessed 10-fold lower levels of hepatic glycogen compared with control littermates, and were unable to normalize their blood glucose levels within 2 h after injection of insulin. The glucose intolerance of the L-PDK1-/- mice may be due to an inability of glucose to suppress hepatic glucose output through the gluconeogenic pathway, since the mRNA encoding hepatic PEPCK (phosphoenolpyruvate carboxykinase), G6Pase (glucose-6-phosphatase) and SREBP1 (sterol-regulatory-element-binding protein 1), which regulate gluconeogenesis, are no longer controlled by feeding. Furthermore, three other insulin-controlled genes, namely IGFBP1 (insulin-like-growth-factor-binding protein-1), IRS2 (insulin receptor substrate 2) and glucokinase, were regulated abnormally by feeding in the liver of PDK1-deficient mice. Finally, the L-PDK1-/- mice died between 4-16 weeks of age due to liver failure. These results establish that the PDK1 signalling pathway plays an important role in regulating glucose homoeostasis and controlling expression of insulin-regulated genes. They suggest that a deficiency of the PDK1 pathway in the liver could contribute to development of diabetes, as well as to liver failure.

No Evidence of Hematopoietic Stem Cell Mobilization in Patients Submitted to Hepatectomy or in Patients With Acute on Chronic Liver Failure

BACKGROUND

Liver regeneration is a heterogeneous phenomenon involving the proliferation of different cell lineages in response to injury. Under a strong positive selection pressure bone marrow derived stem cells may be involved in this process, by making a contribution to both parenchymal restoration and endothelial cell replacement. We investigate bone marrow stem cell migration to the liver in patients undergoing hepatectomy or with acute on chronic liver failure.

METHODS

We enrolled 6 patients submitted to hepatectomy, 6 patients to cholecystectomy and 8 patients with acute decompensation of liver cirrhosis. Mobilization of CD34+ cells was evaluated by cytofluorimetry on peripheral blood samples at different time points; baseline, 1, 3, 7, 15 and 30 days after surgery and at admission, 1, 7 and discharge among patients with acute on chronic liver failure. 10 healthy subjects undergoing blood donation were also enrolled to evaluated the basal value of CD34+ cells.

RESULTS

White blood cell counts remained in the normal range (4.1-9.8 x 10(9)/L) in all groups throughout the follow-up. In all patients of Groups 1, 2 and 3, circulating CD34+ failed to show statistically significant differences both as the absolute number and as the percentage at any time point compared to healthy controls.

CONCLUSIONS

Bone marrow derived cell mobilization can not be detected after hepatectomy or during an acute decompensation on a cirrhotic liver. Under these circumstances liver regeneration can probably call upon mature hepatocytes and endogenous progenitor cells. The involvement of extrahepatic progenitors if any, is a rare and limited phenomenon.

Critical analysis of the pediatric end-stage liver disease scoring system: a single center experience

The Pediatric End-Stage Liver Disease (PELD) scoring system is a new nationally utilized formula developed to provide a continuous numerical assessment of the risk of death in order to allocate livers to children for transplantation. A retrospective review of the clinical course of children undergoing liver transplantation at the Mount Sinai Medical Center was performed in order to assess the effectiveness of this scoring system in the first 24 months of its utilization. Forty-eight patients underwent liver transplantation with overall patient and graft survival rates of 98% and 96%, respectively. In 23 cases the PELD scoring system determined waiting time for transplantation. Of these 23 patients, 7 moved to the intensive care unit (ICU). Only 2 of 23 patients underwent transplantation with their actual PELD score. The rest required petition for exception (17) or status 1 listing (4). Significant morbidity occurred while awaiting transplantation: failure to thrive (78%), ascites (73%), hemorrhage (49%), infectious complications (39%), encephalopathy (30%), peritonitis (17%), pathologic bone fractures (13%), and hepatopulmonary syndrome (9%). In patients with PELD scores granted by exception the average score that did not yield a liver offer was 38 with an average waiting time of 55 days. At the time of transplantation actual PELD score averaged 22, while the petitioned score was 40. Based upon our center's initial experience, the current PELD scoring system is not adequate. Actual PELD scores did not lead to timely allocation of livers to children. It appears that this scoring system underestimates the near-term risk of death. Urgent reassessment is required to prevent potential morbidity and mortality in children. In conclusion the United Network for Organ Sharing policy that permits granting of exceptions has circumvented these problems with the PELD scoring system.