Molecular Adsorbent Recirculating System: clinical experience in patients with liver failure based on hepatitis B in China

Breath Ammonia Is a Useful Biomarker Predicting Kidney Function in Chronic Kidney Disease Patients

Chronic kidney disease (CKD) is a public health problem and its prevalence has increased worldwide; patients are commonly unaware of the condition. The present study aimed to investigate whether exhaled breath ammonia via vertical-channel organic semiconductor (V-OSC) sensor measurement could be used for rapid CKD screening. We enrolled 121 CKD stage 1–5 patients, including 19 stage 1 patients, 26 stage 2 patients, 38 stage 3 patients, 21 stage 4 patients, and 17 stage 5 patients, from July 2019 to January 2020. Demographic and laboratory data were recorded. The exhaled ammonia was collected and rapidly measured by the V-OSC sensor to correlate with kidney function. Results showed no significant difference in age, sex, body weight, hemoglobin, albumin level, and comorbidities in different CKD stage patients. Correlation analysis demonstrated a good correlation between breath ammonia and blood urea nitrogen levels, serum creatinine levels, and estimated glomerular filtration rate (eGFR). Breath ammonia concentration was significantly elevated with increased CKD stage compared with the previous stage (CKD stage 1/2/3/4/5: 636 ± 94; 1020 ± 120; 1943 ± 326; 4421 ± 1042; 12781 ± 1807 ppb, p < 0.05). The receiver operating characteristic curve analysis showed an area under the curve (AUC) of 0.835 (p < 0.0001) for distinguishing CKD stage 1 from other CKD stages at 974 ppb (sensitivity, 69%; specificity, 95%). The AUC was 0.831 (p < 0.0001) for distinguishing between patients with/without eGFR < 60 mL/min/1.73 m² (cutoff 1187 ppb: sensitivity, 71%; specificity, 78%). At 886 ppb, the sensitivity increased to 80% but the specificity decreased to 69%. This value is suitable for kidney function screening. Breath ammonia detection with V-OSC is a real time, inexpensive, and easy to administer measurement device for screening CKD with reliable diagnostic accuracy.

An evaluation of the usefulness of extracorporeal liver support techniques in patients with severe liver dysfunction

INTRODUCTION

The mortality rate in patients with severe liver dysfunction with no option of transplantation is unacceptably high. The main aim of this study was to evaluate the usefulness of applying extracorporeal liver support (ECLS) techniques in this group of patients.

MATERIAL AND METHODS

Data from hospital admissions of 101 patients with severe liver dysfunction who were admitted to the department of Anaesthesiology and intensive therapy between 2006 and 2015 were retrospectively analysed. The study group was divided into two subgroups. Standard Medical therapy (SMT) was a subgroup of patients receiving standard Medical therapy, and SMT + ECLS was a subgroup containing patients receiving standard medical therapy complemented by at least one extracorporeal liver support procedure.

RESULTS

Significantly lower intensive care unit (ICU) mortality and 30-day mortality rates were found in the SMT + ECLS subgroup (p = 0.0138 and p = 0.0238 respectively). No difference in 3-month mortality was identified between the two groups. In a multivariate model, independent risk factors for ICU mortality proved to be the SOFA score and prothrombin time. The highest discriminatory power for ICU mortality was demonstrated for the SOFA score, followed by APACHE II, SAPS II, MELD UNOS and GCS scores. For 30-day mortality, however, the best discriminatory power was shown for the SAPS II score, followed by SOFA, APACHE II, MELD UNOS and GCS scores.

CONCLUSIONS

Further studies are needed to assess the contribution of non-biological extracorporeal liver support procedures to a decrease in mortality rates in the population of patients with severe liver dysfunction.

Depurative capacity of molecular adsorbent recycling system (MARS): A focus on bilirubin removal

The molecular adsorbent recycling system (MARS) is now widely used in the treatment of patients with hepatic failure (HF). A great deal of interest has been directed toward its effect on clinical outcome, whereas its depurative capacity also needs attention. Bilirubin, a tightly albumin-bound toxin accumulating in patients with HF, is regarded as a surrogate to evaluate the depurative capacity of albumin-bound toxins by blood purification modalities. The removal of bilirubin by MARS is difficult to predict, because both the clearance of bilirubin and the reduction ratio of bilirubin after a single session differ between patients and sessions. A reduction of depurative capacity over the course of a treatment is observed. Furthermore, the later sessions are likely less efficient than previous ones. It cannot be taken for granted that the reduction of depurative capacity is due to the saturation and reduced efficiency of the adsorbent columns used in MARS. The answer lies in the property of bilirubin/albumin binding. The removal of bilirubin by MARS is a diffusion process, dependent on the free bilirubin concentration. Bilirubin binds to albumin in 3 ways with different affinity. High-affinity binding bilirubin is difficult to dissociate from albumin and is accompanied by a smaller free fraction, which means it is also difficult for MARS to remove. The factors affecting the free fraction of bilirubin will impact on bilirubin removal by MARS. Among them, the molar ratio of bilirubin to albumin is the most important one. Other factors include the interaction of other agents with bilirubin/albumin binding, the albumin concentration, plasma ion strength, and pH.

Assessment of the Combined Effect of Plasma Exchange and Plasma Perfusion on Patients with Severe Hepatitis Awaiting Orthotopic Liver Transplantation

To determine if plasma exchange combined with plasma perfusion is a reliable and effective temporary liver support treatment for patients on the waiting list for OLT, we tested this method in 5 patients with end-stage and 3 patients with middle-stage severe hepatitis. Four patients were successfully controlled until a donor liver was available 4 to 13 days later. In contrast, the remaining 4 patients were not adequately controlled by this treatment and experienced aggravated disease progression, dying 3 to 8 days after treatment while still awaiting OLT. Of those 4 patients who received OLT, 2 patients died from multi-organ failure caused by hepatic failure, while the other 2 survived. These findings show that plasma exchange combined with plasma perfusion provides temporary support for some patients on the waiting list for OLT. The ability of patients to successfully bridge to OLT is closely associated with the degree of liver failure, complications, multi-organ failure, and the length of the waiting period for a donor liver.

Extracorporeal liver support devices for listed patients

An alternative to liver transplantation for patients with liver failure remains an unmet need. In acute liver failure, the ideal extracorporeal liver support device (ELSD) would replace the functions of the failing liver in order to permit spontaneous recovery, given the incredible regenerative potential of the liver, negating the need for transplantation. In acute-on-chronic liver failure, an ELSD would ideally support hepatic function until a recovery to liver function before acute decompensation or until liver transplantation. In decompensated cirrhosis, an ELSD could again be used to support hepatic function until transplant. In addition, ELSDs may have the potential to treat the multiorgan failure that accompanies liver failure including hepatic encephalopathy, renal failure, and immune dysfunction or indeed potential to promote liver regeneration. Creation of an extracorporeal bioartificial liver able to completely replace liver function remains an unmet need. This review will describe a number of technologies suitable for clinical trials in humans, which have resulted from decades of engineering and biological research to develop a bioreactor able to adequately sustain functional hepatocytes. In addition, this review will describe artificial liver support devices that are primarily designed to replace the detoxifying functions of the liver and will consider the current data available or studies required to support their use in liver failure patients on the transplant waiting list. Liver Transplantation 22 839-848 2016 AASLD.

Hepatic encephalopathy: an updated approach from pathogenesis to treatment

One of the most serious complications of chronic or fulminant liver failure is hepatic encephalopathy (HE), associated most commonly with cirrhosis. In the presence of chronic liver disease, HE is a sign of decompensation, while in fulminant liver failure its development represents a worrying sign and usually indicates that transplantation will be required. Despite the significance of HE in the course of liver disease, the progress in development of new therapeutic options has been unremarkable over the last 20 years. An up-to-date review regarding HE, including both research and review articles. HE is a serious and progressive, but potentially reversible, disorder with a wide spectrum of neuropsychiatric abnormalities and motor disturbances that ranges from mild alteration of cognitive and motor function to coma and death. Although a clear pathogenesis is yet to be determined, elevated ammonia in serum and the central nervous system is the mainstay for pathogenesis and treatment of HE. Management includes early diagnosis and prompt treatment of precipitating factors. Clinical trials and extensive clinical experience have established the efficacy of diverse substances in HE treatment. Novel therapies with clinical promise include: L-ornithine L-aspartate, sodium benzoate, phenylacetate, AST-120, and the molecular adsorbent recirculating system. Eventually, liver transplantation is often the most successful long-term therapy for HE.

Prediction value of model for end-stage liver disease scoring system on prognosis in the acute on chronic liver failure patients with plasma exchange treatment

Hepatitis B virus-related acute-on-chronic liver failure (AoCLF) is associated with a high mortality rate. Plasma exchange (PE) is useful to bridge patients with AoCLF to liver transplantation or recovery. The aim of this study was to analyze the impact of the model for end-stage liver disease (MELD) score on 30-day survival in patients with AoCLF treated with PE or conventional medications and to evaluate the therapeutic effectiveness of PE. In this study, 62 enrolled patients with AoCLF who received PE treatment were compared with 131 patients treated with conventional medications. The MELD scores were calculated according to the original formula, and the 30-day survival in patients was recorded. The 30-day survival rate of the patients who received PE versus controls was 41.9% versus 25.2% (p < 0.05). The 30-day survival rate of patients in the PE group (50.0%) with a MELD score from 20 to 30 was higher than that of the control group (31.7%, p < 0.05); for MELD scores more than 30, there was no significant difference in two groups (8.3% vs. 0%, p > 0.05). PE seems to be efficacious and safe for the treatment of patients with AoCLF and significantly increased the survival rates of patients with a MELD score of 20-30.

Acute liver failure: liver support therapies

PURPOSE OF REVIEW

We summarize the therapeutic approach to patients with acute liver failure with the main focus on bioartificial and artificial liver support. We also describe specific and general therapeutic approaches based upon recent advances in the understanding of the pathophysiology of acute liver failure.

RECENT FINDINGS

Bioartificial liver support systems use hepatocytes in an extracorporeal device connected to the patient's circulation. Artificial liver support is intended to remove protein-bound toxins and water-soluble toxins without providing synthetic function. Both systems improve clinical and biochemical parameters and can be applied safely to patients. Although bioartificial liver-assist devices have not been shown to improve the survival of patients with acute liver failure, further development is underway. Artificial liver support systems have been shown to alter several pathophysiological mechanisms involved in the development of acute liver failure but survival data are still limited.

SUMMARY

Mortality in patients with acute liver failure is still unacceptably high. The most effective treatment, liver transplantation, is a limited resource and so other therapeutic options to bridge patients to recovery or stabilization have to be considered. Better understanding of the pathophysiology of acute liver failure and device development is necessary to achieve the elusive goal of effective extracorporeal liver assist.

MARS in the treatment of liver failure: controversies and evidence

Molecular Adsorbent Recirculation System (MARS) is a form of extracorporeal detoxification system used as an artificial liver support system. Numerous studies have been published on the topic, with the majority of them describing the capability of MARS in removing albumin-bound toxins and improving systemic hemodynamics. Whether such improvement could be translated into survival benefit is still uncertain, given the paucity of randomized controlled trials available. The outcome of patients receiving MARS treatment is difficult to analyze because liver failure patients constitute a heterogeneous population and different subgroups carry different prognoses. An evidence-based recommendation on the timing of MARS initiation is not available and currently MARS is usually commenced for hyperbilirubinemia or presence of complications of liver failure. MARS is in general a safe procedure, but there are still potential complications that need to be cautioned, along with various operative issues that are worth attention. The future prospects of MARS would rely on the completion of adequately powered randomized controlled trials.

Acute fulminant hepatitis B in a patient with diabetic nephropathy treated successfully with concomitant lamivudine and molecular adsorbents recirculating system

A 36-year-old man with type 2 diabetes and diabetic nephropathy treated with hemodialysis developed hepatitis B virus (HBV)-induced acute fulminant hepatic failure (FHF). Despite supportive treatment, the condition rapidly progressed as manifested by severe jaundice, coagulopathy and hepatic coma. He was placed on the waiting list for liver transplantation and was treated with lamivudine and extracoporeal liver support with the molecular adsorbent recirculating system (MARS). After three 8-h sessions of MARS treatment in 1 week, he had remarkable improvement in clinical symptoms and serum biochemistry. On the 14th hospital day, surface antigen seroconversion was noted with undetectable hepatitis B virus surface antigen (HBs Ag) and low titre of anti-HBs antibody, indicating a complete recovery from acute fulminant hepatitis B. MARS treatment has been reported to benefit patients with liver failure from different causes including acute exacerbation of chronic hepatitis B, poisoning, post transplantation and Wilson's disease. The present case suggests its potential benefit when combined with lamivudine in treating uremic patients with acute fulminant hepatitis B.

Molecular adsorbent recirculating system for acute and acute-on-chronic liver failure: a meta-analysis

Molecular adsorbent recirculating system (MARS) is an important option for patients with liver failure to give them additional time for recovery or to serve as a "bridge" to transplantation. However, its effect on survival for such patients is not well known. Our aim was to assess the treatment effects of MARS on patients with acute and acute-on-chronic liver failure. The outcomes measure evaluated was survival. We searched Medline (1966-2002) and EMBASE (1974-2002) using the terms liver failure, liver support systems, and MARS. Our search was extended to the Cochrane Controlled Trials Registry Database, published abstracts from 5 international conferences, Teraklin (the manufacturer of MARS), known contacts, and bibliographies from each full-published report. We included trials published in English and non-English languages. Eligible studies were randomized and nonrandomized controlled trials, which compared the treatment effects of MARS with standard medical treatment. Of the 206 articles screened, 4 randomized controlled trials including 67 patients were analyzed. Two nonrandomized trials with 61 patients were used for explorative analysis. The methodology, population, intervention, and outcomes of each selected trial were evaluated by duplicate independent review. Disagreements were resolved by consensus. In the primary meta-analysis, MARS treatment did not appear to reduce mortality significantly compared with standard medical treatment [relative risk (RR), 0.56; 95% confidence interval (CI), 0.28-1.14; P = .11]. Only 1 of the 4 randomized trials analyzed showed significant reduction in mortality. Sensitivity analysis of 3 peer-reviewed trials did not reduce mortality significantly with MARS treatment (RR, 0.72; 95% CI, 0.37-1.40; P = .33). Subgroup analysis of 2 trials for acute liver failure and another 2 trails for acute-on-chronic liver failure also did not reveal any benefit to survival with MARS treatment. In contrast, explorative analysis of 2 nonrandomized trials showed a significant survival benefit with MARS treatment (RR, 0.36; 95% CI, 0.17-0.76; P = .007). This was possibly related to bias in the selection of patients in the nonrandomized trials. In conclusion, MARS treatment had no significant survival benefit on patients with liver failure when compared with standard medical therapy. However, we found only a few trials with a small number of patients for the analysis, allowing for the possibility of false negative and erroneous conclusions. Well-conducted randomized trials are strongly recommended to define the role of MARS in the treatment of patients with liver failure.

Effects of hemoperfusion adsorption and/or plasma exchange in treatment of severe viral hepatitis: A comparative study

AIM: Non-bioartificial liver has been applied to clinic for quite a long time, but the reported efficacy has been very different. The aim of this study was to compare the efficacy and safety of hemoperfusion adsorption, plasma exchange and plasma exchange plus hemoperfusion adsorption in treatment of severe viral hepatitis.

METHODS: Seventy-five patients with severe viral hepatitis were treated with hemoperfusion adsorption therapy (24 cases), plasma exchange therapy (17 cases) and plasma exchange plus hemoperfusion adsorption therapy (34 cases). The data of liver function, renal function, blood routine test, prothrombin time (PT) and prothrombin activity (PTa) pre-and post-therapy were analyzed.

RESULTS: Clinical symptoms of patients improved after treatment. The levels of aminotransferase, total bilirubin, direct bilirubin decreased significantly after 3 therapies (P < 0.05 or P < 0.01). PT, the level of total serum protein decreased significantly and PTa increased significantly after plasma exchange therapy and plasma exchange plus hemoperfusion adsorption therapy (P < 0.05 or P < 0.01). The side effects were few and mild in all patients.

CONCLUSION: Three therapies were effective in the treatment of severe viral hepatitis. Plasma exchange therapy and plasma exchange plus hemoperfusion adsorption therapy are better than hemoperfusion adsorption therapy.

Role of circulating neurotoxins in the pathogenesis of hepatic encephalopathy: potential for improvement following their removal by liver assist devices

Both acute and chronic liver failure result in impaired cerebral function known as hepatic encephalopathy (HE). Evidence suggests that HE is the consequence of the accumulation in brain of neurotoxic and/or neuroactive substance including ammonia, manganese, aromatic amino acids, mercaptans, phenols, short-chain fatty acids, bilirubin and a variety of neuroactive medications prescribed as sedatives to patients with liver failure. Brain ammonia concentrations may attain levels in excess of 2 mm, concentrations which are known to adversely affect both excitatory and inhibitory neurotransmission as well as brain energy metabolism. Manganese exerts toxic effects on dopaminergic neurones. Prevention and treatment of HE continues to rely heavily on the reduction of circulating ammonia either by reduction of gut production using lactulose or antibiotics or by increasing its metabolism using L-ornithine-L-aspartate. No specific therapies have so far been designed to reduce circulating concentrations of other toxins. Liver assist devices offer a potential new approach to the reduction of circulating neurotoxins generated in liver failure. In this regard, the Molecular Adsorbents Recirculating System (MARS) appears to offer distinct advantages over hepatocyte-based systems.