Summary The peripheral arterial vasodilation hypothesis has been most influential in the field of cirrhosis and its complications. It has given rise to hundreds of pathophysiological studies in ...experimental and human cirrhosis and is the theoretical basis of life-saving treatments. It is undisputed that splanchnic arterial vasodilation contributes to portal hypertension and is the basis for manifestations such as ascites and hepatorenal syndrome, but the body of research generated by the hypothesis has revealed gaps in the original pathophysiological interpretation of these complications. The expansion of our knowledge on the mechanisms regulating vascular tone, inflammation and the host-microbiota interaction require a broader approach to advanced cirrhosis encompassing the whole spectrum of its manifestations. Indeed, multiorgan dysfunction and failure likely result from a complex interplay where the systemic spread of bacterial products represents the primary event. The consequent activation of the host innate immune response triggers endothelial molecular mechanisms responsible for arterial vasodilation, and also jeopardizes organ integrity with a storm of pro-inflammatory cytokines and reactive oxygen and nitrogen species. Thus, the picture of advanced cirrhosis could be seen as the result of an inflammatory syndrome in contradiction with a simple hemodynamic disturbance.
Patients with acutely decompensated cirrhosis have a dismal prognosis and frequently progress to acute-on-chronic liver failure, which is characterised by hepatic and extrahepatic organ failure(s). ...The pathomechanisms involved in decompensation and disease progression are still not well understood, and as specific disease-modifying treatments do not exist, research to identify novel therapeutic targets is of the utmost importance. This review amalgamates the latest knowledge on disease mechanisms that lead to tissue injury and extrahepatic organ failure – such as systemic inflammation, mitochondrial dysfunction, oxidative stress and metabolic changes – and marries these with the classical paradigms of acute decompensation to form a single paradigm. With this detailed breakdown of pathomechanisms, we identify areas for future research. Novel disease-modifying strategies that break the vicious cycle are urgently required to improve patient outcomes.
The pathophysiological background of decompensated cirrhosis is characterised by a systemic proinflammatory and pro-oxidant milieu that plays a major role in the development of multiorgan ...dysfunction. Such abnormality is mainly due to the systemic spread of bacteria and/or bacterial products from the gut and danger-associated molecular patterns from the diseased liver triggering the release of proinflammatory mediators by activating immune cells. The exacerbation of these processes underlies the development of acute-on-chronic liver failure. A further mechanism promoting multiorgan dysfunction and failure likely consists with a mitochondrial oxidative phosphorylation dysfunction responsible for systemic cellular energy crisis. The systemic proinflammatory and pro-oxidant state of patients with decompensated cirrhosis is also responsible for structural and functional changes in the albumin molecule, which spoil its pleiotropic non-oncotic properties such as antioxidant, scavenging, immune-modulating and endothelium protective functions. The knowledge of these abnormalities provides novel targets for mechanistic treatments. In this respect, the oncotic and non-oncotic properties of albumin make it a potential multitarget agent. This would expand the well-established indications to the use of albumin in decompensated cirrhosis, which mainly aim at improving effective volaemia or preventing its deterioration. Evidence has been recently provided that long-term albumin administration to patients with cirrhosis and ascites improves survival, prevents complications, eases the management of ascites and reduces hospitalisations. However, variant results indicate that further investigations are needed, aiming at confirming the beneficial effects of albumin, clarifying its optimal dosage and administration schedule and identify patients who would benefit most from long-term albumin administration.
Albumin infusion reduces the incidence of postparacentesis circulatory dysfunction among patients with cirrhosis and tense ascites, as compared with no treatment. Treatment alternatives to albumin, ...such as artificial colloids and vasoconstrictors, have been widely investigated. The aim of this meta‐analysis was to determine whether morbidity and mortality differ between patients receiving albumin versus alternative treatments. The meta‐analysis included randomized trials evaluating albumin infusion in patients with tense ascites. Primary endpoints were postparacentesis circulatory dysfunction, hyponatremia, and mortality. Eligible trials were sought by multiple methods, including computer searches of bibliographic and databases and the Cochrane Library. Results were quantitatively combined under a fixed‐effects model. Seventeen trials with 1,225 total patients were included. There was no evidence of heterogeneity or publication bias. Compared with alternative treatments, albumin reduced the incidence of postparacentesis circulatory dysfunction (odds ratio OR, 0.39; 95% confidence interval CI, 0.27‐0.55). Significant reductions in that complication by albumin were also shown in subgroup analyses versus each of the other volume expanders tested (e.g., dextran, gelatin, hydroxyethyl starch, and hypertonic saline). The occurrence of hyponatremia was also decreased by albumin, compared with alternative treatments (OR, 0.58; 95% CI, 0.39‐0.87). In addition, mortality was lower in patients receiving albumin than alternative treatments (OR, 0.64; 95% CI, 0.41‐0.98). Conclusions: This meta‐analysis provides evidence that albumin reduces morbidity and mortality among patients with tense ascites undergoing large‐volume paracentesis, as compared with alternative treatments investigated thus far. (HEPATOLOGY 2012)
Since the introduction of human serum albumin as a plasma expander in the 1940s, considerable research has allowed a better understanding of its biochemical properties and potential clinical ...benefits. Albumin has a complex structure, which is responsible for a variety of biological functions. In disease, the albumin molecule is susceptible to modifications that may alter its biological activity. During the last decades, different methods to measure albumin function have been developed. Recent studies have shown that not only albumin concentration but also albumin function is reduced in liver failure. This observation led to the concept of effective albumin concentration, which represents the fact that plasma albumin concentration does not reflect its function. Indeed, in liver disease albumin function is several times less than its concentration. In patients with cirrhosis, albumin infusion reduces mortality in patients with spontaneous bacterial peritonitis and improves outcome following large volume paracentesis. In combination with vasoconstrictors, albumin is useful in the management of patients with hepatorenal syndrome. Its role is being investigated in a large number of indications, which rely on its volume and nonvolume expansion functions such as stroke, severe sepsis, Alzheimer's disease, malaria, burns, and ovarian hyperstimulation syndrome. This review explores the above concepts, reviews the available evidence for the use of albumin in liver diseases, defines therapeutic limitations, and explores the challenges that should be addressed in future research. (Hepatology 2013;58:1836–1846)
Acute-on-chronic liver failure (ACLF), which develops in patients with cirrhosis, is characterized by intense systemic inflammation and organ failure(s). Because systemic inflammation is ...energetically expensive, its metabolic costs may result in organ dysfunction/failure. Therefore, we aimed to analyze the blood metabolome in patients with cirrhosis, with and without ACLF.
We performed untargeted metabolomics using liquid chromatography coupled to high-resolution mass spectrometry in serum from 650 patients with AD (acute decompensation of cirrhosis, without ACLF), 181 with ACLF, 43 with compensated cirrhosis, and 29 healthy individuals.
Of the 137 annotated metabolites identified, 100 were increased in patients with ACLF of any grade, relative to those with AD, and 38 comprised a distinctive blood metabolite fingerprint for ACLF. Among patients with ACLF, the intensity of the fingerprint increased across ACLF grades, and was similar in patients with kidney failure and in those without, indicating that the fingerprint reflected not only decreased kidney excretion but also altered cell metabolism. The higher the ACLF-associated fingerprint intensity, the higher the plasma levels of inflammatory markers, tumor necrosis factor α, soluble CD206, and soluble CD163. ACLF was characterized by intense proteolysis and lipolysis; amino acid catabolism; extra-mitochondrial glucose metabolism through glycolysis, pentose phosphate, and D-glucuronate pathways; depressed mitochondrial ATP-producing fatty acid β-oxidation; and extra-mitochondrial amino acid metabolism giving rise to metabotoxins.
In ACLF, intense systemic inflammation is associated with blood metabolite accumulation and profound alterations in major metabolic pathways, in particular inhibition of mitochondrial energy production, which may contribute to the development of organ failures.
Acute-on-chronic liver failure (ACLF), which develops in patients with cirrhosis, is characterized by intense systemic inflammation and organ failure(s). Because systemic inflammation is energetically expensive, its metabolic costs may result in organ dysfunction/failure. We identified a 38-metabolite blood fingerprint specific for ACLF that revealed mitochondrial dysfunction in peripheral organs. This may contribute to organ failures.
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•Metabolomics performed in sera of a large series of patients with acute decompensation (AD) of cirrhosis, with/without ACLF.•Of the 137 annotated metabolites identified, 100 were increased in patients with ACLF relative to those with AD.•38 metabolites comprised a distinctive ACLF fingerprint, whose intensity correlated with systemic inflammation.•The ACLF fingerprint represented increases in glycolysis and related pathways.•Fingerprint indicated reduced mitochondrial ATP-producing fatty acid β-oxidation which may contribute to organ failure(s).
Acute‐on‐chronic liver failure (ACLF) in cirrhosis is characterized by acute decompensation (AD), organ failure(s), and high short‐term mortality. Recently, we have proposed (systemic inflammation SI ...hypothesis) that ACLF is the expression of an acute exacerbation of the SI already present in decompensated cirrhosis. This study was aimed at testing this hypothesis and included 522 patients with decompensated cirrhosis (237 with ACLF) and 40 healthy subjects. SI was assessed by measuring 29 cytokines and the redox state of circulating albumin (HNA2), a marker of systemic oxidative stress. Systemic circulatory dysfunction (SCD) was estimated by plasma renin (PRC) and copeptin (PCC) concentrations. Measurements were performed at enrollment (baseline) in all patients and sequentially during hospitalization in 255. The main findings of this study were: (1) Patients with AD without ACLF showed very high baseline levels of inflammatory cytokines, HNA2, PRC, and PCC. Patients with ACLF showed significantly higher levels of these markers than those without ACLF; (2) different cytokine profiles were identified according to the type of ACLF precipitating event (active alcoholism/acute alcoholic hepatitis, bacterial infection, and others); (3) severity of SI and frequency and severity of ACLF at enrollment were strongly associated. The course of SI and the course of ACLF (improvement, no change, or worsening) during hospitalization and short‐term mortality were also strongly associated; and (4) the strength of association of ACLF with SI was higher than with SCD. Conclusion: These data support SI as the primary driver of ACLF in cirrhosis. (Hepatology 2016;64:1249‐1264).
Hepatorenal syndrome (HRS), a serious complication of cirrhosis, is associated with high mortality without treatment. Terlipressin with albumin is effective in the reversal of HRS. Where terlipressin ...is not available, as in the United States, midodrine and octreotide with albumin are used as an alternative treatment of HRS. The aim was to compare the effectiveness of terlipressin plus albumin versus midodrine and octreotide plus albumin in the treatment of HRS in a randomized controlled trial. Twenty‐seven patients were randomized to receive terlipressin with albumin (TERLI group) and 22 to receive midodrine and octreotide plus albumin (MID/OCT group). The TERLI group received terlipressin by intravenous infusion, initially 3 mg/24 hours, progressively increased to 12 mg/24 hours if there was no response. The MID/OCT group received midodrine orally at an initial dose of 7.5 mg thrice daily, with the dose increased to a maximum of 12.5 mg thrice daily, together with octreotide subcutaneously: initial dose 100 μg thrice daily and up to 200 μg thrice daily. Both groups received albumin intravenously 1 g/kg of body weight on day 1 and 20‐40 g/day thereafter. There was a significantly higher rate of recovery of renal function in the TERLI group (19/27, 70.4%) compared to the MID/OCT group (6/21, 28.6%), P = 0.01. Improvement in renal function and lower baseline Model for End‐Stage Liver Disease score were associated with better survival. Conclusion: Terlipressin plus albumin is significantly more effective than midodrine and octreotide plus albumin in improving renal function in patients with HRS (Hepatology 2015;62:567–574
Abstract This review summarizes our current understanding of nonalcoholic fatty liver disease (NAFLD), a multi-factorial systemic disease resulting from a complex interaction between a specific ...genetic background and multiple environmental/metabolic “hits”. The role of gut microbiota, lipotoxicity, inflammation and their molecular pathways is reviewed in-depth. We also discuss the epidemiology and natural history of NAFLD by pinpointing the remarkably high prevalence of NAFLD worldwide and its inherent systemic complications: hepatic (steatohepatitis, advanced fibrosis and cirrhosis), cardio-metabolic (cardiovascular disease, cardiomyopathy, arrhythmias and type 2 diabetes) and neoplastic (primary liver cancers and extra-hepatic cancers). Moreover, we critically report on the diagnostic role of non-invasive biomarkers, imaging techniques and liver biopsy, which remains the reference standard for diagnosing the disease, but cannot be proposed to all patients with suspected NAFLD. Finally, the management of NAFLD is also reviewed, by highlighting the lifestyle changes and the pharmacological options, with a focus on the innovative drugs. We conclude that the results of ongoing studies are eagerly expected to lead to introduce into the clinical arena new diagnostic and prognostic biomarkers, prevention and surveillance strategies as well as to new drugs for a tailored approach to the management of NAFLD in the individual patient.
Since the electricity market liberalisation of the mid-1990s, forecasting energy demand and prices in competitive markets has become of primary importance for energy suppliers, market regulators and ...policy makers. In this paper, we propose a non-parametric model to obtain point and interval predictions of price and demand. It does not require any parametric assumption on the distribution of the error term or on the functional relationships linking the response variable to covariates. The assumed location–scale model provides a non-parametric estimation of the conditional mean and of the conditional variance by means of a Generalised Additive Model. Interval forecasts, at any given confidence level, are then obtained using a further non-parametric estimation of the innovation’s quantile. Since both the conditional mean and the conditional variance of the response variable are non-linear functions of covariates depending on calendar factors, renewable energy productions and other market variables, the resulting model is very flexible. It easily adapts to market conditions as well as to the non-linear characteristics of demand, supply and prices. An application to hourly data for the Italian electricity market, over the period 2015–2019 period, shows the one-day-ahead forecasting performance of the model for zonal electricity prices and level of demand.
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