High-density lipoprotein administration attenuates liver proinflammatory response, restores liver endothelial nitric oxide synthase activity, and lowers portal pressure in cirrhotic rats

Cardiometabolic risk factors and clinical course of liver cirrhosis

BACKGROUND

The global prevalence of Metabolic Dysfunction-Associated Liver Disease is dramatically increasing with the diffusion of cardiometabolic risk factors (CMRFs). The aim of the present study was to assess the natural course of liver cirrhosis, in terms of decompensation, development of hepatocellular carcinoma and mortality, in relation to the presence of CMRFs (type 2 diabetes mellitus, obesity, arterial hypertension, low HDL levels, hypertriglyceridemia).

PATIENTS

667 patients with liver cirrhosis (50 with CMRFs and without non-metabolic aetiological factors, 167 with non-metabolic aetiological factors and without CMRFs, and 450 with both non-metabolic aetiological factors and at least one CMRF) followed at the University and General Hospital of Padua, Italy, from 1998 to 2022, were included.

RESULTS

No difference in the occurrence of cirrhosis decompensating events and development of hepatocellular carcinoma was observed, whereas patients in the metabolic or mixed group had 4-3-fold higher all-cause mortality and significantly lower 3-years survival compared to patients in the non-metabolic group, despite a better liver function at enrolment. Hypertriglyceridemia and low HDL levels were the less prevalent CMRFs, but those associated with the highest risk of cirrhosis decompensation. Hypertriglyceridemia was also associated with an increased risk of mortality. Arterial hypertension was associated with a reduced risk of cirrhosis decompensation, but a higher risk of mortality.

CONCLUSION

Compared to patients without CMRFs, those with CMRFs had similar rates of liver cirrhosis decompensation but higher overall mortality. Hypertriglyceridemia was associated with a high risk of both liver decompensation and death.

NOSTRIN is an emerging positive regulator of decompensated cirrhotic patients with portal hypertension

BACKGROUND AND AIMS

Decreased nitric oxide (NO) bioavailability in a cirrhotic liver contributes to high intrahepatic vascular resistance (IHVR) and portal hypertension (PHT). Nostrin is an inhibitory protein of NO synthesising enzyme endothelial NO synthase (eNOS), shown to increase in cirrhosis with PHT, however, the precise molecular mechanism is poorly documented. This study aimed to elucidate the role of Nostrin and associated derangement in hepatic NO generation in cirrhotic liver. Further, we investigate whether Nostrin could be a biomarker in the progression of cirrhosis.

METHODS

This study was conducted on sixty healthy subjects and 120 cirrhotic patients. In addition, liver tissue samples were collected from cirrhotic patients for the analysis of Nostrin, eNOS and inflammatory markers.

RESULTS

When compared to healthy controls, systemic levels of Nostrin and cGMP were elevated in compensated cirrhosis. In decompensated cirrhosis, further robust increases in Nostrin and cGMP were noted. Furthermore, Nostrin expression was considerably higher whilst reduced eNOS activity and hepatic cGMP levels in cirrhotic liver compared to control liver.

CONCLUSIONS

In cirrhotic patients, a robust increase in hepatic Nostrin expression may reduce eNOS activity and associated local NO generation. Furthermore, Blood Nostrin concentration was higher and parallel to disease severity and could be a key diagnostic and prognostic biomarker in cirrhotic patients with PHT.

High-density lipoprotein cholesterol as a prognostic marker for 90-day transplant-free mortality in hepatitis B virus-related acute-on-chronic liver failure

Background

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is linked to dyslipidemia and inflammatory responses. This study aimed to investigate the correlation between high-density lipoprotein cholesterol (HDL-C) levels and 90-day transplant-free (TF) mortality in patients with HBV-ACLF.

Methods

A prospective cohort of 287 patients with HBV-ACLF from Beijing Ditan Hospital was enrolled between January 2016 and December 2019. The prognostic accuracy of lipid profile parameters was evaluated by the area under the receiver operating characteristic curve (AUC), and the association between HDL-C levels and mortality was assessed using a restricted cubic spline analysis. Correlations between lipid profile parameters and inflammatory factors were analyzed. Kaplan-Meier curves were used to assess 90-day TF mortality, and log-rank tests were used for comparison analysis. These results were internally validated between January 2020 and December 2023 (n=125).

Results

Patients with lower HDL-C levels exhibited higher mortality rates (adjusted hazard ratio for HDL-C < 0.13 mmol/L: 4.04, 95% confidence interval: 1.35-11.85) compared with those in the reference group (with HDL-C levels above 0.36 mmol/L). An "L-shaped" association was observed between HDL-C levels and TF mortality. The prognostic value of HDL-C (AUC at day 90: 0.732) was comparable to the model for end-stage liver disease score of 0.729. Additionally, HDL-C levels were inversely correlated with interleukin (IL)-4, IL-6, and tumor necrosis factor-α (all P<0.05). In the training cohort, the 90-day TF mortality rates were 8.3%, 15.2%, 24.0%, and 43.2% for the extremely low, low, medium, and high-risk subgroups, respectively, while in the validation cohort, they were 4.5%, 18.5%, 31.2%, and 44.7%, respectively.

Conclusions

HDL-C levels < 0.13 mmol/L were associated with increased 90-day transplant-free mortality in patients with HBV-ACLF. An inverse correlation was found between HDL-C levels and inflammatory markers.

Clinical Implications of Inflammation in Patients With Cirrhosis

Cirrhosis-associated immune dysfunction refers to the concurrent systemic inflammation and immunoparesis evident across the disease spectrum of chronic liver disease, ranging from the low-grade inflammatory plasma milieu that accompanies compensated disease to the intense high-grade inflammatory state with coexistent severe immune paralysis that defines acute decompensation and acute-on-chronic liver failure. Systemic inflammation plays a crucial role in the disease course of cirrhosis and is a key driver for acute decompensation and the progression from compensated to decompensated cirrhosis. Severe systemic inflammation is fundamental to the development of organ dysfunction and failure and, in its most extreme form, acute-on-chronic liver failure. Systemic inflammation propagates the development of hepatic encephalopathy and hepatorenal syndrome-acute kidney injury. It may also be involved in the pathogenesis of further complications such as hepatocellular carcinoma and mental illness. Those patients with the most profound systemic inflammation have the worst prognosis. Systemic inflammation exerts its negative clinical effects through a number of mechanisms including nitric oxide-mediated increased splanchnic vasodilation, immunopathology, and metabolic reallocation.

Prognostic value of virtual portal pressure gradient response in compensated cirrhotic patients treated with carvedilol

AIM

This study aimed to assess the prognostic significance of virtual portal pressure gradient (vPPG) response to carvedilol in patients with compensated cirrhosis (CC).

METHODS

Compensated cirrhosis patients with high-risk varices were prospectively enrolled to receive carvedilol for prevention of first variceal hemorrhage (VH) and followed up for 1 year. The vPPG response was defined as a reduction of vPPG >10% from baseline after 1-month therapy. Logistic and Cox regression analyses were performed to identify independent predictors for vPPG response and first decompensation, respectively. Competitive risk models were constructed to predict disease progression, and validated using the C-index, Kaplan-Meier analysis, competitive risk analysis, and calibration curves.

RESULTS

A total of 129 patients completed this study, of whom 56 (43.4%) achieved vPPG response and were referred as vPPG responders. Baseline vPPG, red color sign, Model for End-stage Liver Disease score, serum monocyte chemoattractant protein-1 (MCP-1), and laminin levels significantly correlated with vPPG response, which itself was further documented as an independent predictor of VH, ascites, and overall decompensation events in CC. Moreover, the red color sign or Child-Turcotte-Pugh score effectively predicted VH, while ascites correlated well with portal flow velocity or MCP-1. The predictive models for VH and ascites showed a good discrimination with C-index values of 0.747 and 0.689 respectively, and the high consistency on calibration curves.

CONCLUSION

The vPPG response could be used as a noninvasive tool for prediction of disease progression in patients with CC.

Caveolin-1 depletion attenuates hepatic fibrosis via promoting SQSTM1-mediated PFKL degradation in HSCs

The key glycolytic enzyme phosphofructokinase (PFK) is responsible for maintaining glycolytic stability and an important energy source for activating hepatic stellate cells (HSCs). However, its regulation in activated HSCs remains unclear. Caveolin-1 (Cav1), a major constituent of caveolae, has emerged as a key target for triggering glycolysis. However, the relationship between Cav1 and glycolysis during HSC activation is not well established. In this study, Cav1 was upregulated in mouse and human fibrotic liver tissues. We concluded that HSC-specific Cav1 knockdown markedly alleviates liver injury and fibrosis. Mechanistically, Cav1 was elevated during primary mouse HSC activation, competing with SQSTM1 for the regulatory subunit of PFK liver type and inhibiting the SQSTM1-mediated autophagy-independent lysosomal degradation pathway to sustain HSC activation. We also identified the heptapeptide alamandine as a promising therapeutic agent that downregulates Cav1 protein levels via proteasomal degradation and may impair glycolysis. Our study provides evidence of the crucial role and mechanism of Cav1 in the glucose metabolic network in HSCs and highlights Cav1 as a critical therapeutic target for the treatment of liver fibrosis.

Challenges in Diagnosis and Therapeutic Approach of Acute on Chronic Liver Failure-A Review of Current Evidence

Acute-on-chronic liver failure (ACLF) is a syndrome characterized by acute and severe decompensation of chronic liver disease (CLD) correlated with multiple organ failure, poor prognosis, and increased mortality. In 40-50% of ACLF cases, the trigger is not recognized; for many of these patients, bacterial translocation associated with systemic inflammation is thought to be the determining factor; in the other 50% of patients, sepsis, alcohol consumption, and reactivation of chronic viral hepatitis are the most frequently described trigger factors. Other conditions considered precipitating factors are less common, including acute alcoholic hepatitis, major surgery, TIPS insertion, or inadequate paracentesis without albumin substitution. Host response is likely the primary factor predicting ACLF severity and prognosis, the host immune response having a particular significance in this syndrome, together with the inflammatory cascade. The management of ACLF includes both the prevention of the precipitating factors that lead to acute liver decompensation and the support of vital functions, the prevention and management of complications, the estimation of prognosis, and the opportunity for liver transplantation.

Automated Machine Learning in Predicting 30-Day Mortality in Patients with Non-Cholestatic Cirrhosis

OBJECTIVE

To evaluate the feasibility of automated machine learning (AutoML) in predicting 30-day mortality in non-cholestatic cirrhosis.

METHODS

A total of 932 cirrhotic patients were included from the First Affiliated Hospital of Soochow University between 2014 and 2020. Participants were divided into training and validation datasets at a ratio of 8.5:1.5. Models were developed on the H₂O AutoML platform in the training dataset, and then were evaluated in the validation dataset by area under receiver operating characteristic curves (AUC). The best AutoML model was interpreted by SHapley Additive exPlanation (SHAP) Plot, Partial Dependence Plots (PDP), and Local Interpretable Model Agnostic Explanation (LIME).

RESULTS

The model, based on the extreme gradient boosting (XGBoost) algorithm, performed better (AUC 0.888) than the other AutoML models (logistic regression 0.673, gradient boost machine 0.886, random forest 0.866, deep learning 0.830, stacking 0.850), as well as the existing scorings (the model of end-stage liver disease [MELD] score 0.778, MELD-Na score 0.782, and albumin-bilirubin [ALBI] score 0.662). The most key variable in the XGBoost model was high-density lipoprotein cholesterol, followed by creatinine, white blood cell count, international normalized ratio, etc. Conclusion: The AutoML model based on the XGBoost algorithm presented better performance than the existing scoring systems for predicting 30-day mortality in patients with non-cholestatic cirrhosis. It shows the promise of AutoML in its future medical application.

Caveolin-1 Deficiency Protects Mice Against Carbon Tetrachloride-Induced Acute Liver Injury Through Regulating Polarization of Hepatic Macrophages

Polarization of hepatic macrophages plays a crucial role in the injury and repair processes of acute and chronic liver diseases. However, the underlying molecular mechanisms remain elusive. Caveolin-1 (Cav1) is the structural protein of caveolae, the invaginations of the plasma membrane. It has distinct functions in regulating hepatitis, cirrhosis, and hepatocarcinogenesis. Given the increasing number of cases of liver cancer, nonalcoholic steatohepatitis, and non-alcoholic fatty liver disease worldwide, investigations on the role of Cav1 in liver diseases are warranted. In this study, we aimed to investigate the role of Cav1 in the pathogenesis of acute liver injury. Wild-type (WT) and Cav1 knockout (KO) mice (Cav1^tm1Mls) were injected with carbon tetrachloride (CCl₄). Cav1 KO mice showed significantly reduced degeneration, necrosis, and apoptosis of hepatocytes and decreased level of alanine transaminase (ALT) compared to WT mice. Moreover, Cav1 was required for the recruitment of hepatic macrophages. The analysis of the mRNA levels of CD86, tumor necrosis factor (TNF), and interleukin (IL)-6, as well as the protein expression of inducible nitric oxide synthase (iNOS), indicated that Cav1 deficiency inhibited the polarization of hepatic macrophages towards the M1 phenotype in the injured liver. Consistent with in vivo results, the expressions of CD86, TNF, IL-6, and iNOS were significantly downregulated in Cav1 KO macrophages. Also, fluorescence-activated cell sorting (FACS) analysis showed that the proportion of M1 macrophages was significantly decreased in the liver tissues obtained from Cav1 KO mice following CCl₄ treatment. In summary, our results showed that Cav1 deficiency protected mice against CCl₄-induced acute liver injury by regulating polarization of hepatic macrophages. We provided direct genetic evidence that Cav1 expressed in hepatic macrophages contributed to the pathogenesis of acute liver injury by regulating the polarization of hepatic macrophages towards the M1 phenotype. These findings suggest that Cav1 expressed in macrophages may represent a potential therapeutic target for acute liver injury.

Acute Decompensation and Acute-on-Chronic Liver Failure

Liver cirrhosis is a major healthcare problem. Acute decompensation, and in particular its interplay with dysfunction of other organs, is responsible for the majority of deaths in patients with cirrhosis. Acute decompensation has different courses, from stable decompensated cirrhosis over unstable decompensated cirrhosis to pre-acute-on-chronic liver failure and finally acute-on-chronic liver failure, a syndrome with high short-term mortality. This review focuses on the recent developments in the field of acute decompensation and acute-on-chronic liver failure.

The systemic inflammation hypothesis: Towards a new paradigm of acute decompensation and multiorgan failure in cirrhosis

Acute decompensation (AD) of cirrhosis is defined by the development of ascites, hepatic encephalopathy and/or variceal bleeding. Ascites is traditionally attributed to splanchnic arterial vasodilation and left ventricular dysfunction, hepatic encephalopathy to hyperammonaemia, and variceal haemorrhage to portal hypertension. Recent large-scale European observational studies have shown that systemic inflammation is a hallmark of AD. Here we present a working hypothesis, the systemic inflammation hypothesis, suggesting that systemic inflammation through an impairment of the functions of one or more of the major organ systems may be a common theme and act synergistically with the traditional mechanisms involved in the development of AD. Systemic inflammation may impair organ system function through mechanisms which are not mutually exclusive. The first mechanism is a nitric oxide-mediated accentuation of the preexisting splanchnic vasodilation, resulting in the overactivation of the endogenous vasoconstrictor systems which elicit intense vasoconstriction and hypoperfusion in certain vascular beds, in particular the renal circulation. Second, systemic inflammation may cause immune-mediated tissue damage, a process called immunopathology. Finally, systemic inflammation may induce important metabolic changes. Indeed, systemic inflammatory responses are energetically expensive processes, requiring reallocation of nutrients (glucose, amino acids and lipids) to fuel immune activation. Systemic inflammation also inhibits nutrient consumption in peripheral (non-immune) organs, an effect that may provide one mechanism of reallocation and prioritisation of metabolic fuels for inflammatory responses. However, the decrease in nutrient consumption in peripheral organs may result in decreased mitochondrial production of ATP (energy) and subsequently impaired organ function.

HDL cholesterol protects from liver injury in mice with intestinal specific LXRα activation

BACKGROUND AND AIMS

Liver X receptors (LXRs) exert anti-inflammatory effects even though their hepatic activation is associated with hypertriglyceridemia and hepatic steatosis. Selective induction of LXRs in the gut might provide protective signal(s) in the aberrant wound healing response that induces fibrosis during chronic liver injury, without hypertriglyceridemic and steatogenic effects.

METHODS

Mice with intestinal constitutive LXRα activation (iVP16-LXRα) were exposed to intraperitoneal injection of carbon tetrachloride (CCl₄ ) for 8 weeks, and in vitro cell models were used to evaluate the beneficial effect of high-density lipoproteins (HDL).

RESULTS

After CCl₄ treatment, the iVP16-LXRα phenotype showed reduced M1 macrophage infiltration, increased expression M2 macrophage markers, and lower expression of hepatic pro-inflammatory genes. This anti-inflammatory effect in the liver was also associated with decreased expression of hepatic oxidative stress genes and reduced expression of fibrosis markers. iVP16-LXRα exhibited increased reverse cholesterol transport in the gut by ABCA1 expression and consequent enhancement of the levels of circulating HDL and their receptor SRB1 in the liver. No hepatic steatosis development was observed in iVP16-LXRα. In vitro, HDL induced a shift from M1 to M2 phenotype of LPS-stimulated Kupffer cells, decreased TNFα-induced oxidative stress in hepatocytes and reduced NF-kB activity in both cells. SRB1 silencing reduced TNFα gene expression in LPS-stimulated KCs, and NOX-1 and IL-6 in HepG2.

CONCLUSIONS

Intestinal activation of LXRα modulates hepatic response to injury by increasing circulating HDL levels and SRB1 expression in the liver, thus suggesting this circuit as potential actionable pathway for therapy.

HDL-related biomarkers are robust predictors of survival in patients with chronic liver failure

BACKGROUND & AIMS

High-density lipoprotein cholesterol (HDL-C) levels are reduced in patients with chronic liver disease and inversely correlate with disease severity. During acute conditions such as sepsis, HDL-C levels decrease rapidly and HDL particles undergo profound changes in their composition and function. We aimed to determine whether indices of HDL quantity and quality associate with progression and survival in patients with advanced liver disease.

METHODS

HDL-related biomarkers were studied in 508 patients with compensated or decompensated cirrhosis (including acute-on-chronic liver failure [ACLF]) and 40 age- and gender-matched controls. Specifically, we studied levels of HDL-C, its subclasses HDL2-C and HDL3-C, and apolipoprotein A1 (apoA-I), as well as HDL cholesterol efflux capacity as a metric of HDL functionality.

RESULTS

Baseline levels of HDL-C and apoA-I were significantly lower in patients with stable cirrhosis compared to controls and were further decreased in patients with acute decompensation (AD) and ACLF. In stable cirrhosis (n = 228), both HDL-C and apoA-I predicted the development of liver-related complications independently of model for end-stage liver disease (MELD) score. In patients with AD, with or without ACLF (n = 280), both HDL-C and apoA-I were MELD-independent predictors of 90-day mortality. On ROC analysis, both HDL-C and apoA-I had high diagnostic accuracy for 90-day mortality in patients with AD (AUROCs of 0.79 and 0.80, respectively, similar to that of MELD 0.81). On Kaplan-Meier analysis, HDL-C <17 mg/dl and apoA-I <50 mg/dl indicated poor short-term survival. The prognostic accuracy of HDL-C was validated in a large external validation cohort of 985 patients with portal hypertension due to advanced chronic liver disease (AUROCs HDL-C: 0.81 vs. MELD: 0.77).

CONCLUSION

HDL-related biomarkers are robust predictors of disease progression and survival in chronic liver failure.

LAY SUMMARY

People who suffer from cirrhosis (scarring of the liver) have low levels of cholesterol carried by high-density lipoproteins (HDL-C). These alterations are connected to inflammation, which is a problem in severe liver disease. Herein, we show that reduced levels of HDL-C and apolipoprotein A-I (apoA-I, the main protein carried by HDL) are closely linked to the severity of liver failure, its complications and survival. Both HDL-C and apoA-I can be easily measured in clinical laboratories and are as good as currently used prognostic scores calculated from several laboratory values by complex formulas.

Abnormalities of Lipoprotein Levels in Liver Cirrhosis: Clinical Relevance

Progressive lipoprotein impairment occurs in liver cirrhosis and is associated with increased morbidity and mortality. The present review aims to summarize the current evidence regarding the prognostic value of lipoprotein abnormalities in liver cirrhosis and to address the need of a better prognostic stratification of patients, including lipoprotein profile assessment. Low levels of lipoproteins are usual in cirrhosis. Much evidence supports the prognostic role of hypolipidemia in cirrhotic patients. In particular, hypocholesterolemia represents an independent predictor of survival in cirrhosis. In cirrhotic patients, lipoprotein impairment is associated with several complications: infections, malnutrition, adrenal function, and spur cell anemia. Alterations of liver function are associated with modifications of circulating lipids. Decreased levels of lipoproteins significantly impact the survival of cirrhotic patients and play an important role in the pathogenesis of some cirrhosis-related complications.

Interaction between periodontitis and liver diseases

Periodontitis is an oral disease that is highly prevalent worldwide, with a prevalence of 30–50% of the population in developed countries, but only ~10% present with severe forms. It is also estimated that periodontitis results in worldwide productivity losses amounting to ~54 billion USD yearly. In addition to the damage it causes to oral health, periodontitis also affects other types of disease. Numerous studies have confirmed the association between periodontitis and systemic diseases, such as diabetes, respiratory disease, osteoporosis and cardiovascular disease. Increasing evidence also indicated that periodontitis may participate in the progression of liver diseases, such as non-alcoholic fatty liver disease, cirrhosis and hepatocellular carcinoma, as well as affecting liver transplantation. However, to the best of our knowledge, there are currently no reviews elaborating upon the possible links between periodontitis and liver diseases. Therefore, the current review summarizes the human trials and animal experiments that have been conducted to investigate the correlation between periodontitis and liver diseases. Furthermore, in the present review, certain mechanisms that have been postulated to be responsible for the role of periodontitis in liver diseases (such as bacteria, pro-inflammatory mediators and oxidative stress) are considered. The aim of the review is to introduce the hypothesis that periodontitis may be important in the progression of liver disease, thus providing dentists and physicians with an improved understanding of this issue.

Acute-on-chronic liver failure in cirrhosis

The definition of acute-on-chronic liver failure (ACLF) remains contested. In Europe and North America, the term is generally applied according to the European Association for the Study of the Liver-Chronic Liver Failure (EASL-CLIF) Consortium guidelines, which defines this condition as a syndrome that develops in patients with cirrhosis and is characterized by acute decompensation, organ failure and high short-term mortality. One-third of patients who are hospitalized for acute decompensation present with ACLF at admission or develop the syndrome during hospitalization. ACLF frequently occurs in a closed temporal relationship to a precipitating event, such as bacterial infection or acute alcoholic, drug-induced or viral hepatitis. However, no precipitating event can be identified in approximately 40% of patients. The mechanisms of ACLF involve systemic inflammation due to infections, acute liver damage and, in cases without precipitating events, probably intestinal translocation of bacteria or bacterial products. ACLF is graded into three stages (ACLF grades 1-3) on the basis of the number of organ failures, with higher grades associated with increased mortality. Liver and renal failures are the most common organ failures, followed by coagulation, brain, circulatory and respiratory failure. The 28-day mortality rate associated with ACLF is 30%. Depending on the grade, ACLF can be reversed using standard therapy in only 16-51% of patients, leaving a considerable proportion of patients with ACLF that remains steady or progresses. Liver transplantation in selected patients with ACLF grade 2 and ACLF grade 3 increases the 6-month survival from 10% to 80%.

[Aspects of pathogenetc pharmacotherapy for portal hypertension in liver cirrhosis]

The review of literature considers the principles of medical treatment for portal hypertension in liver cirrhosis, which are based on the current views of its development mechanisms. It describes both current pharmacotherapy methods for portal hypertension and drugs, the efficacy of which is being investigated.

Role of Infections in Acute-on-Chronic Liver Failure

Patients with cirrhosis are prone to developing bacterial infections. Moreover, bacterial infection is the most common identifiable trigger of acute-on-chronic liver failure (ACLF), which is characterized by organ failures and a high risk of death. There is evidence of an excessive immune response of the host as a major mechanism leading to the development of organ failures in patients with cirrhosis. However, a role for direct tissue damage caused by bacterial toxins and virulence factors cannot be excluded. Failed tolerance mechanisms may also contribute to organ failures, although the involved mechanisms are unclear. A proportion of patients with infection-related ACLF have a prolonged stay in the intensive care unit. These patients have immune suppression, increased risk of superinfection and poor outcome. Immune suppression might be a consequence of the first infection episode that has led patients to be admitted to hospital.

Contemporary concepts of the medical therapy of portal hypertension under liver cirrhosis

Severe complications of liver cirrhosis are mostly related to portal hypertension. At the base of the pathogenesis of portal hypertension is the increase in hepatic vascular resistance to portal blood flow with subsequent development of hyperdynamic circulation, which, despite of the formation of collateral circulation, promotes progression of portal hypertension. An important role in its pathogenesis is played by the rearrangement of vascular bed and angiogenesis. As a result, strategic directions of the therapy of portal hypertension under liver cirrhosis include selectively decreasing hepatic vascular resistance with preserving or increasing portal blood flow, and correcting hyperdynamic circulation and pathological angiogenesis, while striving to reduce the hepatic venous pressure gradient to less than 12 mmHg or 20% of the baseline. Over the last years, substantial progress in understanding the pathophysiological mechanisms of hemodynamic disorders under liver cirrhosis has resulted in the development of new drugs for their correction. Although the majority of them have so far been investigated only in animal experiments, as well as at the molecular and cellular level, it might be expected that the introduction of the new methods in clinical practice will increase the efficacy of the conservative approach to the prophylaxis and treatment of portal hypertension complications. The purpose of the review is to describe the known methods of portal hypertension pharmacotherapy and discuss the drugs that may affect the basic pathogenetic mechanisms of its development.

A matched cross-sectional study of the association between circulating tissue factor activity, immune activation and advanced liver fibrosis in hepatitis C infection

Background

Tissue factor (TF) is a protein that mediates the initiation of the coagulation cascade. TF expression is increased in patients with poorly-controlled HIV, and may be associated with increased immune activation that leads to cardiovascular morbidity. The role of TF in immune activation in liver disease in hepatitis C virus (HCV)-monoinfection and HIV/HCV-coinfection has not been explored.

Methods

Fifty-nine patients were stratified: A) HIV-monoinfection (N = 15), B) HCV-monoinfection with chronic hepatitis C (CHC) (N = 15), C) HIV/HCV-coinfection with CHC (N = 14), and D) HIV/HCV-seropositive with cleared-HCV (N = 15). All HIV+ patients had undetectable HIV viremia. Whole blood was collected for CD4/CD8 immune activation markers by flow cytometry and plasma was assayed for microparticle TF (MPTF) activity. Subjects underwent transient elastography (TE) to stage liver fibrosis. Undetectable versus detectable MPTF was compared across strata using Fisher's Exact test.

Results

MPTF activity was more frequently detected among patients with HCV-monoinfection (40%), compared to HIV-monoinfection and HIV/HCV-seropositive with cleared HCV (7%) and HIV/HCV-coinfection with CHC (14%) (p = 0.02). Mean TE-derived liver stiffness score in kPa was higher in patients with detectable MPTF (12.4 ± 8.5) than those with undetectable MPTF (6.4 ± 3.0) (p = 0.01). Mean CD4 + HLADR+ and CD4 + CD38-HLADR+ expression were higher in those with detectable MPTF (44 ± 9.8% and 38 ± 8.7%, respectively) than those with undetectable MPTF (36 ± 11% and 31 ± 10.4% respectively) (p = 0.05 and 0.04 respectively).

Conclusions

HCV-monoinfection and HIV/HCV-coinfection with CHC were associated with MPTF activity. MPTF activity is also associated with advanced liver fibrosis and with CD4 + HLADR+ immune activation.

Acute-on-chronic liver failure: A new syndrome that will re-classify cirrhosis

Acute-on-chronic liver failure (ACLF) is a recently recognized syndrome characterized by acute decompensation (AD) of cirrhosis and organ/system failure(s) (organ failure: liver, kidney, brain, coagulation, circulation and/or respiration) and extremely poor survival (28-day mortality rate 30-40%). ACLF occurs in relatively young patients. It is especially frequent in alcoholic- and untreated hepatitis B associated-cirrhosis, in addition it is related to bacterial infections and active alcoholism, although in 40% of cases no precipitating event can be identified. It may develop at any time during the course of the disease in the patient (from compensated to long-standing cirrhosis). The development of ACLF occurs in the setting of a systemic inflammation, the severity of which correlates with the number of organ failures and mortality. Systemic inflammation may cause ACLF through complex mechanisms including an exaggerated inflammatory response and systemic oxidative stress to pathogen- or danger/damage-associated molecular patterns (immunopathology) and/or alteration of tissue homeostasis to inflammation caused either by the pathogen itself or through a dysfunction of tissue tolerance. A scoring system composed of three scores (CLIF-C OFs, CLIF-C AD, and CLIF-C ACLFs) specifically designed for patients with AD, with and without ACLF, allows a step-wise algorithm for a rational indication of therapy. The management of ACLF should be carried out in enhanced or intensive care units. Current therapeutic measures comprise the treatment for associated complications, organ failures support and liver transplantation.

Gut-liver axis in liver cirrhosis: How to manage leaky gut and endotoxemia

A “leaky gut” may be the cutting edge for the passage of toxins, antigens or bacteria into the body, and may play a pathogenic role in advanced liver cirrhosis and its complications. Plasma endotoxin levels have been admitted as a surrogate marker of bacterial translocation and close relations of endotoxemia to hyperdynamic circulation, portal hypertension, renal, cardiac, pulmonary and coagulation disturbances have been reported. Bacterial overgrowth, increased intestinal permeability, failure to inactivate endotoxin, activated innate immunity are all likely to play a role in the pathological states of bacterial translocation. Therapeutic approach by management of the gut-liver axis by antibiotics, probiotics, synbiotics, prebiotics and their combinations may improve the clinical course of cirrhotic patients. Special concern should be paid on anti-endotoxin treatment. Adequate management of the gut-liver axis may be effective for prevention of liver cirrhosis itself by inhibiting the progression of fibrosis.

Inflammation and portal hypertension - the undiscovered country

Portal hypertension has traditionally been viewed as a progressive process, involving ultrastructural changes including fibrosis, nodule formation, and vascular thrombosis, leading to increased intrahepatic resistance to flow. However, it is increasingly recognized that a significant component of this vascular resistance results from a dynamic process, regulated by complex interactions between the injured hepatocyte, the sinusoidal endothelial cell, the Kupffer cell and the hepatic stellate cell, which impact on sinusoidal calibre. Recent findings suggest these haemodynamic findings are most marked in patients with superimposed inflammation. The precise mechanisms for vascular dysfunction in cirrhosis with superimposed inflammation remain to be fully elucidated but several studies over the past decade have started to generate the hypothesis that inflammation may be a key mediator of the pathogenesis and severity of portal hypertension in this context. This review provides a comprehensive overview of the biological mechanisms for inflammation playing a key role in the severity of portal hypertension, and illustrates potential novel therapies that act by modifying these processes.

Bacterial infections in cirrhosis: a position statement based on the EASL Special Conference 2013

Bacterial infections are very common and represent one of the most important reasons of progression of liver failure, development of liver-related complications, and mortality in patients with cirrhosis. In fact, bacterial infections may be a triggering factor for the occurrence of gastrointestinal bleeding, hypervolemic hyponatremia, hepatic encephalopathy, kidney failure, and development of acute-on-chronic liver failure. Moreover, infections are a very common cause of repeated hospitalizations, impaired health-related quality of life, and increased healthcare costs in cirrhosis. Bacterial infections develop as a consequence of immune dysfunction that occurs progressively during the course of cirrhosis. In a significant proportion of patients, infections are caused by gram-negative bacteria from intestinal origin, yet gram-positive bacteria are a frequent cause of infection, particularly in hospitalized patients. In recent years, infections caused by multidrug-resistant bacteria are becoming an important clinical problem in many countries. The reduction of the negative clinical impact of infections in patients with cirrhosis may be achieved by a combination of prophylactic measures, such as administration of antibiotics, to reduce the occurrence of infections in high-risk groups together with early identification and management of infection once it has developed. Investigation on the mechanisms of altered gut microflora, translocation of bacteria, and immune dysfunction may help develop more effective and safe methods of prevention compared to those that are currently available. Moreover, research on biomarkers of early infection may be useful in early diagnosis and treatment of infections. The current manuscript reports an in-depth review and a position statement on bacterial infections in cirrhosis.

The emerging roles of microvesicles in liver diseases

Microvesicles (MVs) are extracellular vesicles released by virtually all cells, under both physiological and pathological conditions. They contain lipids, proteins, RNAs and microRNAs and act as vectors of information that regulate the function of target cells. This Review provides an overview of the studies assessing circulating MV levels in patients with liver diseases, together with an insight into the mechanisms that could account for these changes. We also present a detailed analysis of the implication of MVs in key processes of liver diseases. MVs have a dual role in fibrosis as certain types of MVs promote fibrolysis by increasing expression of matrix metalloproteinases, whereas others promote fibrosis by stimulating processes such as angiogenesis. MVs probably enhance portal hypertension by contributing to intrahepatic vasoconstriction, splanchnic vasodilation and angiogenesis. As MVs can modulate vascular permeability, vascular tone and angiogenesis, they might contribute to several complications of cirrhosis including hepatic encephalopathy, hepatopulmonary syndrome and hepatorenal syndrome. Several results also suggest that MVs have a role in hepatocellular carcinoma. Although MVs represent promising biomarkers in patients with liver disease, methods of isolation and subsequent analysis must be standardized.

Pre-primary and Primary Prophylaxis of Variceal Hemorrhage

Variceal hemorrhage is a life-threatening complication of portal hypertension. Thus, prevention of variceal formation (pre-primary prophylaxis) or at least prevention of variceal bleeding are important goals to improve life quality and—if possible—survival of patients with liver cirrhosis. Interruption of the underlying cause of liver disease is the most successful approach, which, however, often fails. For this situation interruption or modulation of different pathophysiological mechanisms leading to fibrosis, hyperdynamic circulation and portal hypertension have been shown effective in animal models. But few could be translated to humans. By contrast, different steps to prevent first bleeding from varices have proven successful in many clinical trials. These applied mainly drugs to lower portal pressure, such as nonselective β-blockers, or endoscopic obliteration of varices, while prophylactic shunt procedures are not advised.

Acute-on chronic liver failure

Acute-on-chronic liver failure (ACLF) is an increasingly recognised entity encompassing an acute deterioration of liver function in patients with cirrhosis, which is usually associated with a precipitating event and results in the failure of one or more organs and high short term mortality. Prospective data to define this is lacking but there is a large body of circumstantial evidence suggesting that this condition is a distinct clinical entity. From the pathophysiologic perspective, altered host response to injury and infection play important roles in its development. This review focuses upon the current understanding of this syndrome from the clinical, prognostic and pathophysiologic perspectives and indicates potential biomarkers and therapeutic targets for intervention.

Abnormal plasma microparticles impair vasoconstrictor responses in patients with cirrhosis

BACKGROUND & AIMS

Circulating membrane-shed microparticles (MPs) participate in regulation of vascular tone. We investigated the cellular origins of MPs in plasma from patients with cirrhosis and assessed the contribution of MPs to arterial vasodilation, a mechanism that contributes to portal hypertension.

METHODS

We analyzed MPs from blood samples of 91 patients with cirrhosis and 30 healthy individuals (controls) using flow cytometry; their effects on the vascular response to vasoconstrictors were examined in vitro and in vivo.

RESULTS

Circulating levels of leuko-endothelial (CD31(+)/41(-)), pan-leukocyte (CD11a(+)), lymphocyte (CD4(+)), and erythrocyte (CD235a(+)) MPs were higher in patients with cirrhosis than in controls. Plasma of patients with cirrhosis contained hepatocyte-derived MPs (cytokeratin-18(+)), whereas plasma from controls did not. The severity of cirrhosis and systemic inflammation were major determinants of the levels of leuko-endothelial and hepatocyte MPs. MPs from patients with advanced cirrhosis significantly impaired contraction of vessels in response to phenylephrine, whereas MPs from healthy controls or from patients of Child-Pugh class A did not. This effect depended on cyclooxygenase type 1 and required phosphatidylserine on the surface of MPs. Intravenous injection of MPs from patients with cirrhosis into BALB/C mice decreased mean arterial blood pressure.

CONCLUSIONS

Cirrhosis is associated with increases in circulating subpopulations of MPs, likely resulting from systemic inflammation and liver cell damage. The overall pool of circulating MPs from patients with advanced cirrhosis impairs vasoconstrictor responses and decreases blood pressure, contributing to the arterial vasodilation associated with portal hypertension.

Endothelial dysfunction in the regulation of cirrhosis and portal hypertension

Portal hypertension is caused by an increased intrahepatic resistance, a major consequence of cirrhosis. Endothelial dysfunction in liver sinusoidal endothelial cells (LSECs) decreases the production of vasodilators, such as nitric oxide, and favours vasoconstriction. This contributes to an increased vascular resistance in the intrahepatic/sinusoidal microcirculation and develops portal hypertension. Portal hypertension, in turn, causes endothelial dysfunction in the extrahepatic, i.e. splanchnic and systemic, circulation. Unlike dysfunction in LSECs, endothelial dysfunction in the splanchnic and systemic circulation causes overproduction of vasodilator molecules, leading to arterial vasodilation. In addition, portal hypertension leads to the formation of portosystemic collateral vessels. Both arterial vasodilation and portosystemic collateral vessel formation exacerbate portal hypertension by increasing the blood flow through the portal vein. Pathological consequences, such as oesophageal varices and ascites, result. While the sequence of pathological vascular events in cirrhosis and portal hypertension has been elucidated, the underlying cellular and molecular mechanisms causing endothelial dysfunctions are not yet fully understood. This review article summarizes the current cellular and molecular studies on endothelial dysfunctions found during the development of cirrhosis and portal hypertension with a focus on the intra- and extrahepatic circulations. The article ends by discussing the future directions of the study for endothelial dysfunction.

Gut microbiota and diabetes: from pathogenesis to therapeutic perspective

More than several hundreds of millions of people will be diabetic and obese over the next decades in front of which the actual therapeutic approaches aim at treating the consequences rather than causes of the impaired metabolism. This strategy is not efficient and new paradigms should be found. The wide analysis of the genome cannot predict or explain more than 10-20% of the disease, whereas changes in feeding and social behavior have certainly a major impact. However, the molecular mechanisms linking environmental factors and genetic susceptibility were so far not envisioned until the recent discovery of a hidden source of genomic diversity, i.e., the metagenome. More than 3 million genes from several hundreds of species constitute our intestinal microbiome. First key experiments have demonstrated that this biome can by itself transfer metabolic disease. The mechanisms are unknown but could be involved in the modulation of energy harvesting capacity by the host as well as the low-grade inflammation and the corresponding immune response on adipose tissue plasticity, hepatic steatosis, insulin resistance and even the secondary cardiovascular events. Secreted bacterial factors reach the circulating blood, and even full bacteria from intestinal microbiota can reach tissues where inflammation is triggered. The last 5 years have demonstrated that intestinal microbiota, at its molecular level, is a causal factor early in the development of the diseases. Nonetheless, much more need to be uncovered in order to identify first, new predictive biomarkers so that preventive strategies based on pre- and probiotics, and second, new therapeutic strategies against the cause rather than the consequence of hyperglycemia and body weight gain.

Endotoxin and tumor necrosis factor-receptor levels in portal and hepatic vein of patients with alcoholic liver cirrhosis receiving elective transjugular intrahepatic portosystemic shunt

BACKGROUND/AIMS

In cirrhosis portal hypertension can promote bacterial translocation and increase serum endotoxin levels. Vice versa, endotoxin aggravates portal hypertension by induction of systemic and splanchnic vasodilation, and by triggering hepatic inflammatory response via tumor necrosis factor α (TNFα). However, the hepatic elimination of endotoxin in cirrhotic patients with severe portal hypertension, in the absence of acute complications, has not been investigated so far.

METHODS

Twenty patients with alcoholic liver cirrhosis received transjugular intrahepatic portosystemic shunt at an event-free interval for either refractory ascites or recurrent bleeding. During the transjugular intrahepatic portosystemic shunt procedure portal and hepatic venous blood samples were obtained and endotoxin levels were measured by a chromogenic limulus-assay. In 16 of these patients an enzyme-linked immunosorbent assay was used to measure levels of the soluble TNFα-receptors sTNF-R55 and sTNF-R75.

RESULTS

Portal venous endotoxin levels correlated with portal vein velocity (P=0.03) and arterial systolic blood pressure (P=0.007). Portal endotoxin levels correlated with portal venous sTNF-R75-levels (P=0.039; r=0.521) and hepatic venous sTNF-R55-levels (P=0.009; r=0.669). Hepatic venous levels of both sTNF-R55 and sTNF-R75 correlated directly with the model for end-stage liver disease-score, and inversely with cholinesterase. However, we did not find significant differences in endotoxin levels nor in sTNF-R55-levels and sTNF-R75-levels between portal and hepatic venous blood.

CONCLUSION

Endotoxin levels correlated with hemodynamic derangement in cirrhotic severe portal hypertension, and with levels of soluble TNFα-receptors. Soluble TNFα-receptor levels correlated with the severity of liver dysfunction. However, in this study an endotoxin concentration gradient across the liver was absent, suggesting negligible primary hepatic endotoxin elimination in the absence of complications.

The rno-miR-34 family is upregulated and targets ACSL1 in dimethylnitrosamine-induced hepatic fibrosis in rats

The mechanisms whereby hepatic fibrosis develops in chronic liver diseases remain incompletely defined. Here, we sought to examine whether microRNA (miRNA) became dysregulated in dimethylnitrosamine-induced hepatic fibrosis in rats. Our microarray analysis revealed that the miR-34 family was upregulated along with other miRNAs in liver fibrotic tissues. Six miRNAs, such as rno-miR-878, were downregulated. The findings were confirmed by RT-PCR assays. Gene ontology analysis further showed that many of these dysregulated miRNAs were involved in lipid/fatty acid metabolism. The acyl-CoA synthetase long-chain family member 1 (ACSL1) gene contained specific binding sites for miR-34a/miR-34c. Additional enhanced green fluorescence protein reporter activity assays indicated that the miR-34 family targeted ACSL1. Our RT-PCR and immunoblotting assays further demonstrated that both the mRNA and protein levels of ACSL1 were markedly reduced in fibrotic liver tissues. Our findings suggest that miRNA becomes dysregulated during hepatic fibrosis, and that the miR-34 family may be involved in the process by targeting ACSL1.

Lipopolysaccharide (LPS) induction of nitric oxide synthase-2 and cyclooxygenase-2 is impaired in fructose overloaded rats

AIMS

Fructose (F) overload in rats induces metabolic dysfunctions that resemble the human metabolic syndrome. In this paper, we aimed to investigate the response of F overload rats to lipopolysaccharide (LPS) challenge in terms of nitric oxide (NO) production and prostanoids (PR) release.

MAIN METHODS

NO blood steady-state concentration was monitored through the detection of nitrosyl-hemoglobin complexes (NO-Hb) by electronic spin resonance. Production of 6-keto PGF(1)α, PGE(2), PGF(2)α and TXB(2) was measured in aorta and mesenteric beds by HPLC. Western blot analysis was used to examine the changes in the expression levels of NOS-2 and COX-2 in aorta.

KEY FINDINGS

Our results showed that increases in NO circulating steady-state concentration and PR production by aorta and mesenteric beds 6h after LPS administration were significantly attenuated in F overload rats with respect to control animals. Oxidative stress parameters were equally affected in the presence or absence of the F treatment. Aorta protein levels of NOS-2 and COX-2, two enzymes inducible by LPS, were significantly lower in F overload rats with respect to control rats at the end of the treatment (-39% and -61% for NOS-2 and COX-2 respectively).

SIGNIFICANCE

These results suggest that the metabolic alterations established by 15 weeks of F overload should affect the response to LPS challenge due to an attenuation in the induction of NOS-2 and COX-2. This effect would be one of the components contributing to abnormalities in the course of the inflammatory response in other conditions associated to insulin resistance, such as diabetes.

The inverse association of serum HBV DNA level with HDL and adiponectin in chronic hepatitis B infection

BACKGROUND

The natural history of hepatitis B virus (HBV) is complex and influenced by the level of viral replication and host factors. The hepatoprotective role of high density lipoproteins (HDL) and adiponectin as host factors on HBV persistence is less well understood.

METHODS

To investigate correlation between HBV DNA level with clinical parameters in patients with chronic hepatitis B, 92 male subjects with HBV infection without any risk factors for diabetes were enrolled in this study. Age and BMI of the study population were matched and HBV DNA, ALT, tumor necrosis factor alpha (TNF-α), adiponectin and lipid levels was measured.

RESULTS

Serum HBV DNA correlated inversely with serum HDL level (r = -0.23; P = 0.014). The median of log copies/ml for HBV DNA (3.67) was considered as cut off point. Patients with HBV DNA level higher than cut off point had lower adiponectin (8.7 ± 5.3 vs 10.7 ± 4.9 μg/ml p = 0.05). Also, adiponectin had a negative correlation with TNF-α (r = -0.21, P = 0.04) and positive correlations with HDL (r = 0.18, P = 0.043). Multivariate regression models show that serum HDL level is an independent factor to predict serum HBV DNA.

CONCLUSION

Our findings showed that higher HBV DNA levels are associated with lower HDL and adiponectin but induced TNF-alpha values.

Bile duct ligation: step-by-step to cholangiocyte inflammatory tumorigenesis

Chronic liver inflammation after murine bile duct ligation could evolve according to three interrelated phenotypes, which would have different metabolic, functional and histologic characteristics. Liver injury secondary to extrahepatic cholestasis would induce an early ischemic-reperfusion phenotype with cholangiocyte depolarization, abnormal ion transport, hypometabolism with anaerobic glycolysis and hepatocytic apoptosis. This phenotype, in turn, could trigger the switch to a leukocytic phenotype by the cholangiocytes, with an intense anaplerotic activity, hypermetabolism, extracellular matrix degradation and moderated proliferation to create a pseudotissue with metabolic autonomy and paracrine functions. In the long-term cholestasis-drive tumorigenesis, the tumorous tissue would principally consist of cholangiocyte parenchyma, with an impressive biosynthetic activity through the tricarboxylic cell cycle. In terms of the tumorous stroma, made up by fibroplasia and angiogenesis, it would favor the tumor trophism. In conclusion, the great intensity and persistence in the expression of these phenotypes by the cholestatic cholangiocyte would favor chronic inflammatory tumorigenesis.

Assessment of adrenal function in cirrhotic patients: salivary cortisol should be preferred

BACKGROUND & AIMS

Adrenal insufficiency is a common disorder among cirrhotic patients. Adrenal function is usually assessed with serum total cortisol assays. Free cortisol (active fraction) represents only 10% of serum total cortisol, the remaining 90% being linked to cortisol-binding globulin (CBG) and albumin. In cirrhotic patients, the synthesis of these proteins is reduced, which could lead to an overestimation of the prevalence of adrenal insufficiency. Salivary cortisol assessment adequately reflects free cortisol plasma concentration. However, this method has never been validated in cirrhotic patients. The objectives of this report were to assess the following parameters by a prospective observational study: (1) correlation between salivary, serum total and free cortisol, (2) adrenal insufficiency prevalence using salivary and serum assays, (3) parameters associated with a discrepancy between both tests, and (4) adrenal insufficiency risk factors among cirrhotic patients.

METHODS

Salivary and serum total cortisol were assessed before and 1h following an injection of corticotropin (250 microg) in patients hospitalized for cirrhosis complications without shock. CBG was measured and free cortisol was assessed by the Coolens formula.

RESULTS

Eighty-eight patients were included in the study (Child-Pugh C: 68.2%). Free cortisol was more strongly correlated with salivary than with serum total cortisol (Spearman coefficient=0.91 vs. 0.76, respectively, p<0.001). Among included patients, 9.1% had adrenal insufficiency according to salivary cortisol and 33.0% had adrenal insufficiency according to serum total cortisol (p=0.001). Hypoalbuminemia was the only factor associated with a discrepancy between the results of both tests. Adrenal insufficiency risk factors were ascites and low HDL-cholesterol plasma concentration.

CONCLUSION

Using serum total cortisol assays overstate adrenal insufficiency prevalence among cirrhotic patients, mainly because of inaccurate concentrations related to hypoalbuminemia. Salivary cortisol assays should be preferably used in these patients.

[Current problems in the prevention and treatment of infections in patients with cirrhosis]

Infections in patients with cirrhosis are a common complication causing substantial morbidity and mortality. Bacterial translocation plays an important role in the pathogenesis of many infections in cirrhosis. In turn, infections are involved in the pathogenesis of many episodes of decompensated cirrhosis, such as esophageal variceal bleeding, renal insufficiency, the hemodynamic alterations of cirrhosis, and hepatic encephalopathy. Spontaneous bacterial peritonitis is currently the most frequent infection in cirrhosis. Mortality from this entity has recently decreased due to early diagnosis, the use of appropriate antibiotic therapy, and albumin administration. However, infections due to multiresistant microorganisms have recently increased, leading to greater mortality. Primary prophylaxis with quinolones is effective in preventing infections and is associated with lower mortality in a selected population of patients with liver cirrhosis.

Splanchnic Th(2) and Th(1) cytokine redistribution in microsurgical cholestatic rats

BACKGROUND

Long-term extrahepatic cholestasis in the rat induces ductular proliferation and fibrosis in the liver, portal hypertension, splenomegaly, portosystemic collateral circulation, and ascites. These splanchnic alterations could have an inflammatory pathophysiology.

MATERIAL AND METHODS

We measured serum levels of hepatobiliary injury markers and the acute phase proteins, alpha-1-major acid protein (alpha(1)-MAP) and alpha-1-acid glycoprotein (alpha(1)-GPA) in rats 6 wk after microsurgical extrahepatic cholestasis. We also assayed Th(1) (TNF-alpha and IL-1beta) and Th(2) (IL-4 and IL-10) cytokine levels in the liver, ileum, spleen, and mesenteric lymph complex by enzyme-linked immunosorbent assay (ELISA) techniques. Liver fibrosis was measured by Sirius red stain and by using an image system computer-assisted method and mast cell liver infiltration by Giemsa stain.

RESULTS

The cholestatic rats showed an increase (P<0.001) in serum levels of bile acids, total and direct bilirubin, AST, ALT, AST/ALT index, gamma-GT, alkaline phosphatase, alpha(1)- MAP, alpha(1)-GPA, and LDH (P<0.05) in relation to sham-operated rats. TNF-alpha, IL-1beta, IL-4, and IL-10 increased in the ileum (P<0.01) and mesenteric lymph complex (P<0.001), and decreased in the liver (P<0.001). A marked bile proliferation associated with fibrosis (P<0.001) and mast cell infiltration was also shown in the liver of cholestatic rats.

CONCLUSION

The splanchnic redistribution of cytokines, with an increase of Th(1) and Th(2) production in the small bowel and in the mesenteric lymph complex, supports the key role of inflammatory mechanisms in rats with secondary biliary fibrosis.

Lipoprotein metabolism mediates the association of MTP polymorphism with beta-cell dysfunction in healthy subjects and in nondiabetic normolipidemic patients with nonalcoholic steatohepatitis

Nonalcoholic steatohepatitis (NASH) predicts incident diabetes independently of insulin resistance, adiposity and metabolic syndrome through unclear mechanisms. Dietary fat consumption and lipoperoxidative stress predispose to diabetes in the general population and to liver injury in NASH. Microsomal triglyceride transfer protein (MTP) polymorphism modulates lipoprotein metabolism in the general population and liver disease in NASH; a functional MTP polymorphism recently predicted incident diabetes independently of insulin resistance in the general population. We simultaneously assessed the impact of MTP polymorphism, diet, adipokines and lipoprotein metabolism, on glucose homeostasis in NASH. MTP -493G/T polymorphism, dietary habits, adipokines and postprandial triglyceride-rich lipoproteins, high-density lipoprotein cholesterol (HDL-C) and oxidized low-density lipoprotein (oxLDL) responses to an oral fat load, were cross-sectionally correlated to oral glucose tolerance test- and frequently sampled intravenous glucose tolerance test-derived Minimal Model indexes of glucose homeostasis in 40 nondiabetic normolipidemic patients with NASH and 40 age-,sex- and body mass index-matched healthy controls. Despite comparable insulin resistance, fasting lipids, adipokines and dietary habits, MTP GG genotype had significantly more severe beta-cell dysfunction; higher plasma Tg, FFA, intestinal and hepatic very low-density lipoprotein 1 subfractions and oxLDL responses and deeper HDL-C fall than GT/TT carriers in patients and controls. Postprandial HDL-C and oxLDL responses independently predicted beta-cell dysfunction and mediated the effect of MTP polymorphism on beta-cell function. In nondiabetic normolipidemic NASH, MTP -493G/T polymorphism modulates beta-cell function, an effect mediated by postprandial HDL-C and oxLDL metabolism. The impact of this polymorphism on the risk of diabetes and the efficacy of lipid-lowering therapies in restoring beta-cell function in NASH, even with normal fasting lipid values, warrant further investigation.

[Progress in portal hypertension]

In patients with portal hypertension due to cirrhosis, the mechanisms responsible for circulatory modifications are well-known. An elevation in intrahepatic vascular resistance related to a hepatic endothelin hyperproduction and an arterial nitric oxide (NO) hyperproduction. The presence and the degree of portal hypertension might be determined by the measurement of the hepatic venous pressure gradient but non-invasive technique as FibroTest or FibroScan might be useful to estimate the presence of severe portal hypertension. Numerous substances decrease portal pressure either by reducing hepatic vascular resistance or by reducing portal tributary blood flow. The combination of both types of substances is probably the best pharmacological treatment of portal hypertension but further hemodynamic and clinical studies are needed.

Possible mechanisms involved in the discrepancy of hepatic and aortic endothelial nitric oxide synthases during the development of cirrhosis in rats

BACKGROUND/AIM

In cirrhosis, systemic nitric oxide (NO) overproduction and hepatic NO hypoproduction lead to arterial vasodilatation and portal hypertension. The mechanisms involved in these alterations in endothelial NO synthase (eNOS)-derived NO production in hepatic and systemic vasculature remain unknown. The aim of this study was to evaluate the regulation of eNOS and its major modulators in the liver and aorta during the development of cirrhosis in rats.

METHODS

Activated eNOS and Akt and expressions, and caveolin-1 (Cav-1) and scavenger receptor class B type I (SR-BI) expressions were measured before and 1, 2, 3 and 4 weeks after bile duct ligation. Plasma high-density lipoprotein (HDL) levels were measured.

RESULTS

Activated aortic eNOS increased at week 1, whereas it began to decrease at week 3 in the liver. Aortic expression of Cav-1 decreased at week 3 while hepatic expression increased by four-fold. Activated aortic Akt increased progressively while in the liver it gradually decreased during the development of cirrhosis. HDL levels decreased during the first week and decreased thereafter. The hepatic expression of SR-BI decreased.

CONCLUSION

This study shows that the modulation of Akt and Cav-1 is inverted in the liver and the aorta during the development of cirrhosis. In addition, decreased HDL levels may play a role in reduced hepatic eNOS activity.