Liver dialysis in acute-on-chronic liver failure: current and future perspectives

Bridging to Allotransplantation-Is Pig Liver Xenotransplantation the Best Option?

In the past 20 y, the number of patients in the United States who died while waiting for a human donor liver totaled >52 000. The median national wait time for patients with acute liver failure and the most urgent liver transplant listing was 7 d in 2018. The need for a clinical "bridge" to allotransplantation is clear. Current options for supporting patients with acute liver failure include artificial liver support devices, extracorporeal liver perfusion, and hepatocyte transplantation, all of which have shown mixed results with regard to survival benefit and are largely experimental. Progress in the transplantation of genetically engineered pig liver grafts in nonhuman primates has grown steadily, with survival of the pig graft extended to almost 1 mo in 2017. Further advances may justify consideration of a pig liver transplant as a clinical bridge to allotransplantation. We provide a brief history of pig liver xenotransplantation, summarize the most recent progress in pig-to-nonhuman primate liver transplantation models, and suggest criteria that may be considered for patient selection for a clinical trial of bridging by genetically engineered pig liver xenotransplantation to liver allotransplantation.

Albumin in Advanced Liver Diseases: The Good and Bad of a Drug!

Human serum albumin is the most abundant plasma protein, and it regulates diverse body functions. In patients with advanced and decompensated cirrhosis, serum albumin levels are low because of a reduction in the hepatocyte mass due to disease per se and multiple therapeutic interventions. Because of their oncotic and nononcotic properties, administration of human albumin solutions (HAS) have been found to be beneficial in patients undergoing large-volume paracentesis or who have hepatorenal syndrome or spontaneous bacterial peritonitis. Albumin also improves the functionality of the immune cells and mitigates the severity and risk of infections in advanced cirrhosis. Its long-term administration can modify the course of decompensated cirrhosis patients by reducing the onset of new complications, improving the quality of life, and probably providing survival benefits. There is, however, a need to rationalize the dose, duration, and frequency of albumin therapy in different liver diseases and stages of cirrhosis. In patients with acute-on-chronic liver failure, potentially toxic oxidized isoforms of albumin increase substantially, especially human nonmercaptalbumin and 2, and nitrosoalbumin. The role of administration of HAS in such patients is unclear. Determining whether removal of the pathological and dysfunctional albumin forms in these patients by "albumin dialysis" is helpful, requires additional studies. Use of albumin is not without adverse events. These mainly include allergic and transfusion reactions, volume overload, antibody formation and coagulation derangements. Considering their cost, limited availability, need for a health care setting for their administration, and potential adverse effects, judicious use of HAS in liver diseases is advocated. There is a need for new albumin molecules and economic alternatives in hepatologic practice.

Therapeutic plasma-exchange improves systemic inflammation and survival in acute-on-chronic liver failure: A propensity-score matched study from AARC

BACKGROUND AND AIM

Plasma-exchange (PE) has improved survival in acute liver failure by ameliorating systemic inflammatory response syndrome (SIRS). We evaluated PE and compared it to Fractional Plasma Separation and Adsorption (FPSA) and standard medical treatment (SMT) in a large multinational cohort of ACLF patients.

METHODS

Data were prospectively collected from the AARC database and analysed. Matching by propensity risk score (PRS) was performed. Competing risk survival analysis was done to identify deaths because of multiorgan failure (MOF). In a subset of 10 patients, we also evaluated the mechanistic basis of response to PE.

RESULTS

ACLF patients (n = 1866, mean age 44.3 ± 12.3 yrs, 93% males, 65% alcoholics) received either artificial liver support (ALS) (n = 162); [PE (n = 131), FPSA (n = 31)] or were continued on standard medical therapy (SMT) (n = 1704). In the PRS-matched cohort (n = 208, [ALS-119; PE-94, FPSA-25)], SMT-89). ALS therapies were associated with a significantly higher resolution of SIRS (Odd's ratio 9.23,3.42-24.8), lower and delayed development of MOF (Hazard ratio 7.1, 4.5-11.1), and lower liver-failure-related deaths as compared to FPSA and SMT (P < .05). PE cleared inflammatory cytokines, damage-associated molecular patterns, and endotoxin in all patients. Responders improved monocyte phagocytic function and mitochondrial respiration and increased the anti-inflammatory cytokine interleukin-1 receptor antagonist (IL-1RA) compared to non-responders. PE was associated with lesser adverse effects as compared to FPSA.

CONCLUSIONS

PE improves systemic inflammation and lowers the development of MOF in patients with ACLF. Plasma-exchange provides significant survival benefit over FPSA and could be a preferred modality of liver support for ACLF patients.

Predictors of steroid non-response and new approaches in severe alcoholic hepatitis

Severe alcoholic hepatitis (SAH) remains a disease with high mortality. Steroid is the main stay and has been shown to give modest 28-day survival benefit in carefully selected patients, but no 90-day survival benefit. Since non-responders have high incidence of infections and increased mortality, it would be worthwhile to identify them before starting steroid therapy. A high and rising bilirubin, urinary acetyl carnitine >2,500 ng/mL, high asiloglycoprotein positive microparticles, and specific features in liver biopsy could predict steroid non-response at baseline. There is an ever-growing need to find new and effective therapies for SAH patients. Besides aggressive nutrition, granulocyte colony stimulating factor, fecal microbiota transplantation, and plasma exchange appear promising therapies and provide a hope for steroid ineligible or steroid non-responsive patients. Suppression of hepatic inflammation, preventing new bacterial or fungal infections, and enhancing liver regeneration will remain the key targets for next generation therapies.

Effect of artificial liver support system on short-term prognosis of patients with hepatitis B virus-related acute-on-chronic liver failure

Hepatitis B virus-related acute-on-chronic liver failure (HBV-ACLF) is difficult to treat and carries a high risk of short-term mortality. This study aimed to explore the effect of artificial liver support system (ALSS) on the survival of HBV-ACLF patients and to investigate which HBV-ACLF patients may benefit from ALSS treatment. We enrolled 132 patients hospitalized for HBV-ACLF according to the criteria of the Chinese Group on the Study of Severe Hepatitis B-ACLF (COSSH-ACLF) from 425 ACLF patients who were determined to at least meet the Asian Pacific Association for the Study of the Liver criteria and followed up for 90 days. Overall 132 eligible patients were divided into two groups: standard medical treatment (SMT) group, which included 54 patients who underwent SMT alone, and ALSS group, which included 78 patients who underwent ALSS treatment plus SMT. The proportion of HBV-ACLF grade 1, 2, and 3 was 57.69%, 37.18%, and 5.13% in the ALSS group and 51.85%, 35.19%, and 12.96% in the SMT group, respectively. Bacterial infection was present in 43.6% of patients in the ALSS group and in 55.6% of patients in the SMT group. The mortality rates in the ALSS group at 28 and 90 days were significantly lower than those in the SMT group (23.08% vs. 48.15% and 33.33% vs. 57.41%, P < 0.05). ALSS was an independent factor related to both the 28- and 90-day survival of HBV-ACLF patients. Particularly, a higher cumulative survival rate in either patients with HBV-ACLF grade 1 or those with HBV-ACLF with bacterial infection was observed in the ALSS group. Moreover, ALSS had an independent influence on mortality. Based on the COSSH-ACLF criteria, ALSS could better improve the short-term survival of HBV-ACLF patients than SMT alone, especially in those with HBV-ACLF grade 1 or HBV-ACLF with infection.

Liver Tissue Engineering as an Emerging Alternative for Liver Disease Treatment

Chronic liver diseases affect thousands of lives throughout the world every year. The shortage of liver donors for transplantation has been the main driving force to employ alternative methods such as liver tissue engineering (LTE) in fabricating a three-dimensional transplantable liver tissue or enhancing cell delivery techniques alleviating the need for liver donors. LTE consists of three components, cells, ECM (extracellular matrix), and signaling molecules, which we discuss the first and second. The three most common cell sources used in LTE are human and animal primary hepatocytes, and stem cells for different applications. Two major categories of ECM are used to mimic the microenvironment of these cells, named scaffolds and microbeads. Scaffolds have been made by numerous methods with a wide range of synthetic and natural biomaterials. Cell encapsulation has also been utilized by many polymeric biomaterials. To investigate their functions, many properties have been discussed in the literature, such as biochemical, geometrical, and mechanical properties, in both of these categories. Overall, LTE shows excellent potential in assisting hepatic disorders. However, some challenges exist that prevent the practical use of it clinically, making LTE an ongoing research subject in the scientific society.

Extracorporeal liver support in patients with liver failure: a systematic review and meta-analysis of randomized trials

PURPOSE

Acute liver failure (ALF) and acute on chronic liver failure (ACLF) are associated with significant mortality and morbidity. Extracorporeal liver support (ECLS) devices have been used as a bridge to liver transplant; however, the efficacy and safety of ECLS are unclear. We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs) to examine the efficacy and safety of ECLS in liver failure.

METHODS

We searched MEDLINE, EMBASE and Cochrane Central Register of Controlled Trials from inception through March 13, 2019. RCTs comparing ECLS to usual care in ALF or ACLF were included. We used the Grading of Recommendations Assessment, Development and Evaluation approach to assess the certainty of the evidence.

RESULTS

We identified 25 RCTs (1796 patients). ECLS use was associated with reduction in mortality (RR 0.84; 95% CI 0.74, 0.96, moderate certainty) and improvement in hepatic encephalopathy (HE) (RR 0.71; 95% CI 0.60, 0.84, low certainty) in patients with ALF or ACLF. The effect of ECLS on hypotension (RR 1.46; 95% CI 0.98, 2.2, low certainty), bleeding (RR 1.21; 95% CI 0.88, 1.66, moderate certainty), thrombocytopenia (RR 1.62; 95% CI 1.0, 2.64, very low certainty) and line infection (RR 1.92; 95% CI 0.11, 33.44, low certainty) was uncertain.

CONCLUSIONS

ECLS may reduce mortality and improve HE in patients with ALF and ACLF. The effect on other outcomes is uncertain. However, the evidence is limited by risk of bias and imprecision, and larger trials are needed to better determine the effect of ECLS on patient-important outcomes.

Therapeutic effect of double plasma molecular adsorption system and sequential half-dose plasma exchange in patients with HBV-related acute-on-chronic liver failure

Objective

The artificial liver support system (ALSS) is used frequently as a first‐line treatment for hepatitis B virus‐associated acute‐on‐chronic liver failure (HBV‐ACLF). This study aims to compare the therapeutic efficacy of double plasma molecular adsorption system (DPMAS) with sequential half‐dose plasma exchange (PE) (DPMAS+PE) and full‐dose PE in patients with HBV‐ACLF.

Methods

A total of 131 hospitalized patients who were diagnosed with HBV‐ACLF and underwent DPMAS+PE or PE were retrospectively analyzed. According to the treatment methods used, they were divided into PE group (n = 77) and DPMAS+PE group (n = 54). The main evaluation indexes included the change of liver function and the 28‐days liver transplant‐free survival rates after the different treatments.

Results

There were no significant differences on severity of illness between PE group and DPMAS+PE group (P > 0.05). The total bilirubin (TBIL) levels immediately after treatment, and at 24 and 72 hours after treatment were markedly decreased in DPMAS+PE group than that in PE group (52.3 ± 9.4% vs 42.3 ± 7.2%, P < 0.05; 24.2 ± 10.0% vs 13.5 ± 13.0%, P < 0.05; 24.8 ± 13.1% vs 14.9 ± 14.9%, P < 0.05; respectively). The 28‐days survival rates was 62.3% and 72.2% in PE and DPMAS+PE groups (P = 0.146). Furthermore, the 28‐days survival rates were significantly higher in DPMAS+PE group than that in PE group (57.4% vs 41.7%, P = 0.043) in the intermediate‐advanced stage patients.

Conclusion

Compared with PE alone, DPMAS+PE might more effectively improve temporary TBIL in ACLF patients, and improve the 28‐days survival rates in HBV‐ACLF patients with intermediate‐advanced stage. Therefore, DPMAS+PE may be an available ALSS treatment for HBV‐ACLF patients.

Circulating proteomic panels for diagnosis and risk stratification of acute-on-chronic liver failure in patients with viral hepatitis B

Chronic HBV infection (CHB) can lead to acute-on-chronic liver failure (HBV-ACLF) characterized by high mortality. This study aimed to reveal ACLF-related proteomic alterations, from which protein based diagnostic and prognostic scores for HBV-ACLF were developed. Methods: Ten healthy controls, 16 CHB, and 19 HBV-ACLF according to COSSH (Chinese group on the study of severe hepatitis B) criteria were enrolled to obtain the comprehensive proteomic portrait related to HBV-ACLF initiation and progression. Potential markers of HBV-ACLF were further selected based on organ specificity and functionality. An additional cohort included 77 healthy controls, 92 CHB and 71 HBV-ACLF was used to validate the proteomic signatures via targeted proteomic assays. Results: Significant losses of plasma proteins related to multiple functional clusters, including fatty acid metabolism/transport, immuno-response, complement and coagulation systems, were observed in ACLF patients. In the validation study, 28 proteins were confirmed able to separate ACLF, CHB patients. A diagnostic classifier P4 (APOC3, HRG, TF, KLKB1) was built to differentiate ACLF from CHB with high accuracy (auROC = 0.956). A prognostic model P8 (GC, HRG, HPR, SERPINA6, age, NEU, INR and total protein) was built to distinguish survivors from non-survivors in 28 and 90-days follow-up (auROC = 0.882, 0.871), and to stratify ACLF patients into risk subgroups showing significant difference in 28 and 90-days mortality (HR=7.77, 7.45, both P<0.0001). In addition, P8 score correlated with ACLF grades and numbers of extra-hepatic organ failures in ACLF patients, and was able to predict ACLF-associated coagulation and brain failure within 90 days (auROC = 0.815, 0.842). Conclusions: Proteomic signatures developed in this study reflected the deficiency of key hematological functions in HBV-ACLF patients, and show potential for HBV-ACLF diagnosis and risk prediction in complementary to current clinical based parameters.

Management of acute-on-chronic liver failure: an algorithmic approach

Acute-on-chronic liver failure (ACLF) is a distinct syndrome of liver failure in a patient with chronic liver disease presenting with jaundice, coagulopathy and ascites and/or hepatic encephalopathy, developing following an acute hepatic insult and associated with high 28-day mortality. The definition though lacks global consensus, excludes patients with known distinct entities such as acute liver failure and those with end-stage liver disease. The initial Systemic Inflammatory Response Syndrome (SIRS) because of cytokine storm in relation to acute insult and/or subsequent development of sepsis due to immunoparalysis leads to extrahepatic organ failure. These cascades of events progress through a 'Golden Window' period of about 7 days, subsequent to which majority of the patients develop complications, such as sepsis and extrahepatic organ failure. Prevention of sepsis, support of organs and management of organ failure (commonly hepatic, renal, cerebral, coagulation) and early referral for transplant is crucial. The APASL ACLF research consortium (AARC) liver failure score is a dynamic prognostic model for management decisions and is superior to existing models. Aggressive multidisciplinary approach can lead to a transplant-free survival in nearly half of the cases. The present review provides an algorithmic approach to management of organ failure, sepsis prevention, use of dynamic prognostic models for management decision and is aimed to improve the skills for managing and improving the outcomes of such critically ill patients.

Umbilical Cord-Derived Mesenchymal Stem Cell Transplantation in Hepatitis B Virus Related Acute-on-Chronic Liver Failure Treated with Plasma Exchange and Entecavir: a 24-Month Prospective Study

BACKGROUND & AIM

Search for an effective therapy for patients with hepatitis B virus related acute-on-chronic liver failure (HBV-ACLF) remains an important issue. This study investigated the efficacy of umbilical cord-derived mesenchymal stem cell (UC-MSC) transplantation in patients with HBV-ACLF.

METHODS

45 consecutive entecavir-treated HBV-ACLF patients were prospectively studied. Among these patients, 11 received both plasma exchange (PE) and a single transplantation of UC-MSCs (group A), while 34 received only PE (group B). The primary endpoint was survival at 24 months.

RESULTS

Compared with group B, levels of albumin, alanine aminotransferase, aspartate aminotransferase, total bilirubin, direct bilirubin, prothrombin time (PT), international normalized ratio (INR) and model for end-stage liver disease score in group A improved significantly at 4 weeks after transplantation (p < 0.05). Levels of albumin, PT and INR in group A were also markedly improved at 24 months (p < 0.05). Group A had significantly higher cumulative survival rate at 24 months (54.5 % v.s. 26.5 %, p = 0.015 by log rank test). Between the two groups, levels of creatinine, White blood cell, hemoglobin and platelet were similar. HBeAg loss and hepatocellular carcinoma incidence were similar at 24 months. Group assignment (relative risk: 2.926, 95%confidence interval: 1.043-8.203, p = 0.041) was an independent predictor for survival at 24 months. Success rate of UC-MSC transplantation was 100 % in group A. No severe adverse event was observed in any patient.

CONCLUSION

UC-MSC transplantation is safe and effective for HBV-ACLF patients treated with PE and entecavir. It further improves the hepatic function and survival.

Therapeutic plasma exchange versus double plasma molecular absorption system in hepatitis B virus-infected acute-on-chronic liver failure treated by entercavir: A prospective study

BACKGROUND

Therapeutic plasma exchange (TPE) and double plasma molecular absorption system (DPMAS) were two extracorporeal liver support systems. Few studies compared their efficacy profile.

OBJECTIVE

This study was to compare the efficacy of TPE and DPMAS on acute-on-chronic liver failure (ACLF) caused by hepatitis B virus (HBV-ACLF).

METHODS

60 HBV-ACLF patients were enrolled and prospectively studied. All patients received entecavir therapy, and were assigned to TPE group (n = 33) and DPMAS group (n = 27). Primary end-points were the effects of TPE and DPMAS on liver function and serum inflammatory markers.

RESULTS

Serum procalcitonin, interleukin (IL)-6, and high sensitive C-reactive protein (hsCRP) were significantly elevated in patients with HBV-ACLF. TPE achieved significantly higher removal rates of total bilirubin (TBIL, P = .002), direct bilirubin (DBIL, P = .006), and hsCRP (P = .010) than DPMAS, but DPMAS displayed lower loss rate of albumin (P = .000). TPE and DPMAS resulted in similarly increased serum IL-6 levels and comparable 12-week survivals (P > .05). Multivariate analysis showed that hospital stay (Relative Risk [RR]: 1.062, 95% Confidence Interval [CI]: 1.011-1.115, P = .016), prothrombin time (RR: 1.346, 95% CI: 1.077-1.726, P = .010), and international normalized ratio (RR: 0.013, 95% CI: 0.006-0.788, P = .041) were independent predictors for 12-week survival. Both TPE and DPMAS treatments were well-tolerated.

CONCLUSION

Compared to DPMAS, TPE was more efficient in eliminating TBIL, DBIL, and hsCRP, but it was associated with higher loss rate of albumin. TPE and DPMAS were similar in improving 12-week survivals in HBV-ACLF.

Acute-on-chronic liver failure: terminology, mechanisms and management

Acute-on-chronic liver failure (ACLF) is a distinct clinical entity and differs from acute liver failure and decompensated cirrhosis in timing, presence of acute precipitant, course of disease and potential for unaided recovery. The definition involves outlining the acute and chronic insults to include a homogenous patient group with liver failure and an expected outcome in a specific timeframe. The pathophysiology of ACLF relates to persistent inflammation, immune dysregulation with initial wide-spread immune activation, a state of systematic inflammatory response syndrome and subsequent sepsis due to immune paresis. The disease severity and outcome can be predicted by both hepatic and extrahepatic organ failure(s). Clinical recovery is expected with the use of nucleoside analogues for hepatitis B, and steroids for severe alcoholic hepatitis and, possibly, severe autoimmune hepatitis. Artificial liver support systems help remove toxins and metabolites and serve as a bridge therapy before liver transplantation. Hepatic regeneration during ongoing liver failure, although challenging, is possible through the use of growth factors. Liver transplantation remains the definitive treatment with a good outcome. Pre-emptive antiviral agents for hepatitis B before chemotherapy to prevent viral reactivation and caution in using potentially hepatotoxic drugs can prevent the development of ACLF.

Acute-on-chronic liver failure: Pathogenesis, prognostic factors and management

Acute-on-chronic liver failure (ACLF) is increasingly recognized as a complex syndrome that is reversible in many cases. It is characterized by an acute deterioration of liver function in the background of a pre-existing chronic liver disease often associated with a high short-term mortality rate. Organ failure (OF) is always associated, and plays a key role in determining the course, and the outcome of the disease. The definition of ACLF remains controversial due to its overall ambiguity, with several disparate criteria among various associations dedicated to the study of liver diseases. Although the precise pathogenesis needs to be clarified, it appears that an altered host response to injury might be a contributing factor caused by immune dysfunction, ultimately leading to a pro-inflammatory status, and eventually to OF. The PIRO concept (Predisposition, Insult, Response and Organ Failure) has been proposed to better approach the underlying mechanisms. It is accepted that ACLF is a different and specific form of liver failure, where a precipitating event is always involved, even though it cannot always be ascertained. According to several studies, infections and active alcoholism often trigger ACLF. Viral hepatitis, gastrointestinal haemorrhage, or drug induced liver injury, which can also provoke the syndrome. This review mainly focuses on the physiopathology and prognostic aspects. We believe these features are essential to further understanding and providing the rationale for improveddisease management strategies.