Liver transplantation for acute liver failure: are there thresholds not to be crossed?

Acute liver failure

Acute liver failure (ALF) is a life-threatening disorder characterised by rapid deterioration of liver function, coagulopathy, and hepatic encephalopathy in the absence of pre-existing liver disease. The cause of ALF varies across the world. Common causes of ALF in adults include drug toxicity, hepatotropic and non-hepatotropic viruses, herbal and dietary supplements, antituberculosis drugs, and autoimmune hepatitis. The cause of liver failure affects the management and prognosis, and therefore extensive investigation for cause is strongly suggested. Sepsis with multiorgan failure and cerebral oedema remain the leading causes of death in patients with ALF and early identification and appropriate management can alter the course of ALF. Liver transplantation is the best current therapy, although the role of artificial liver support systems, particularly therapeutic plasma exchange, can be useful for patients with ALF, especially in non-transplant centres. In this Seminar, we discuss the cause, prognostic models, and management of ALF.

Liver transplantation for acute liver failure and acute-on-chronic liver failure

Acute liver failure (ALF) and acute-on-chronic liver (ACLF) are distinct phenotypes of liver failure and, thus, need to be compared and contrasted for appropriate management. There has been a significant improvement in the outcomes of these patients undergoing liver transplantation (LT). Survival post-LT for ALF and ACLF ranges between 90% and 95% and 80% and 90% at 1 year, futility criteria have been described in both ALF and ACLF where organ failures define survival. Plasma exchange and continuous renal replacement therapy may serve as bridging therapies. Identifying the futility of LT is as necessary as the utility of LT in patients with ALF and ACLF. The role of regenerative therapies such as granulocyte colony-stimulating factors in ACLF and hepatocyte and xenotransplantation in both conditions remains uncertain. Measures to increase the donor pool through increasing deceased donor transplants in Asian countries, living donations in Western countries, auxiliary liver transplants, and ABO-incompatible liver transplants are necessary to improve the survival of these patients. In this review, we discuss the similarities and differences in clinical characteristics and the timing and outcomes of LT for ALF and ACLF, briefly highlighting the role of bridging therapies and providing an overview of recent advances in the management of ALF and ACLF.

N-3 Polyunsaturated Fatty Acids and Their Lipid Mediators as A Potential Immune-Nutritional Intervention: A Molecular and Clinical View in Hepatic Disease and Other Non-Communicable Illnesses

In recent years, the beneficial effect of n-3 polyunsaturated fatty acids (n-3 PUFAs) intake on human health has been widely accepted in the field of immunonutrition. Today, we find a diversity of supplements based on n-3 PUFAs and/or minerals, vitamins and other substances. The main objective of this review is to discuss the importance of n-3 PUFAs and their derivatives on immunity and inflammatory status related to liver disease and other non-communicable illnesses. Based on the burden of liver diseases in 2019, more than two million people die from liver pathologies per year worldwide, because it is the organ most exposed to agents such as viruses, toxins and medications. Consequently, research conducted on n-3 PUFAs for liver disease has been gaining prominence with encouraging results, given that these fatty acids have anti-inflammatory and cytoprotective effects. In addition, it has been described that n-3 PUFAs are converted into a novel species of lipid intermediaries, specialized pro-resolving mediators (SPMs). At specific levels, SPMs improve the termination of inflammation as well as the repairing and regeneration of tissues, but they are deregulated in liver disease. Since evidence is still insufficient to carry out pharmacological trials to benefit the resolution of acute inflammation in non-communicable diseases, there remains a call for continuing preclinical and clinical research to better understand SPM actions and outcomes.

Liver transplantation in acute liver failure: Dilemmas and challenges

Acute liver failure (ALF) refers to a state of severe hepatic injury that leads to altered coagulation and sensorium in the absence of pre-existing liver disease. ALF has different causes, but the clinical characteristics are strikingly similar. In clinical practice, however, inconsistency in the definition of ALF worldwide and confusion regarding the existence of pre-existing liver disease raise diagnostic dilemmas. ALF mortality rates used to be over 80% in the past; however, survival rates on medical treatment have significantly improved in recent years due to a greater understanding of pathophysiology and advances in critical care management. The survival rates in acetaminophen-associated ALF have become close to the post-transplant survival rates. Given that liver transplantation (LT) is an expensive treatment that involves a major surgical operation in critically ill patients and lifelong immunosuppression, it is very important to select accurate patients who may benefit from it. Still, emergency LT remains a lifesaving procedure for many ALF patients. However, there is a lack of consistency in current prognostic models that hampers the selection of transplant candidates in a timely and precise manner. The other problems associated with LT in ALF are the shortage of graft, development of contraindications on the waiting list, vaguely defined delisting criteria, time constraints for pre-transplant evaluation, ethical concerns, and comparatively poor post-transplant outcomes in ALF. Therefore, there is a desperate need to establish accurate prognostic models and explore the roles of evolving adjunctive and alternative therapies, such as liver support systems, plasma exchange, stem cells, auxiliary LT, and so on, to enhance transplant-free survival and to fill the void created by the graft shortage

Liver transplantation for acute liver failure due to antitubercular drugs - a single-center experience

OBJECTIVES

Patients receiving treatment for tuberculosis are at risk of developing acute liver failure due to the hepatotoxicity of antitubercular drugs. We aimed to describe our experience with liver transplantation from deceased donors in this situation.

METHODS

We identified patients undergoing transplantation for acute liver failure due to antitubercular drugs in our prospectively maintained database.

RESULTS

Of 81 patients undergoing transplantation for acute liver failure, 8 cases were attributed to antitubercular drugs during the period of 2006-2016. Regarding the time of tuberculosis treatment until the onset of jaundice, patients were on antitubercular drugs for a mean of 64.7 days (21-155 days). The model for end-stage liver disease (MELD) score of patients ranged from 32 to 47 (median 38), and seven patients underwent transplantation under vasopressors. The 1-year survival was 50%. Three patients died during the week following transplantation due to septic shock (including a patient with acute liver failure due to hepatic/disseminated tuberculosis), and the remaining patient died 2 months after transplantation due to pulmonary infection. There were 2 cases of mild rejection and 1 case of moderate rejection. Of the surviving patients, all were considered cured of tuberculosis after alternative drugs were given.

CONCLUSION

Patients arrived very sick and displayed poor survival after deceased donor transplantation.

Protective effect of Coptisine from Rhizoma Coptidis on LPS/D-GalN-induced acute liver failure in mice through up-regulating expression of miR-122

Coptisine (COP), one of the main active ingredients of Rhizoma Coptidis, reportedly has anti-inflammatory, anti-colon cancer properties, but it remains elusive whether COP owns hepatoprotective activity. Mice were pretreated with COP for 7d prior to lipopolysaccharide/d-galactosamine (LPS/D-GalN) administration to detect the hepatic protective effects of COP. The mechanism was explored in using HepG2 cells with low level of miR-122 and LO2 cells with high level of miR-122, combining with miR-122 agomir transfection by means of detecting the expression of miR-122 and proteins, clinical index and apoptosis. COP ameliorated the LPS/D-GalN-induced liver failure by lowering serum levels of ALT and AST, raising hepatic GSH and SOD levels, and maintaining the morphology of hepatocytes, along with an increase in miR-122 expression in mice. The results in vitro indicated that, after miR-122 mimic administration, the alone treatment of COP and the co-treatment of COP and LPS transfection obviously promoted the apoptosis of HepG2, which was increased by 152.67% and 113.97% compared with NC (P < 0.05 vs NC). LPS significantly induced the apoptosis of L02 cells, but COP treatment attenuated that of L02 cells. Further analysis showed that COP increased the miR-122 level and the expression of Bax, cleaved-casp3 and decreased Bcl-2, Bcl-xL in LPS-treated HepG2 cells. COP increased the miR-122 level but decreased the expression of TLR4, Bcl-2, Bcl-xL in LPS-treated L02 cells. COP attenuated LPS/D-GalN-induced ALF by up-regulating the level of miR-122, synergistically promoting apoptosis, and suggesting COP which showed a potential protective effect on ALF.

Intraportal mesenchymal stem cell transplantation prevents acute liver failure through promoting cell proliferation and inhibiting apoptosis

BACKGROUND

Transplantation of mesenchymal stem cells (MSCs) has been regarded as a potential treatment for acute liver failure (ALF), but the optimal route was unknown. The present study aimed to explore the most effective MSCs transplantation route in a swine ALF model.

METHODS

The swine ALF model induced by intravenous injection of D-Gal was treated by the transplantation of swine MSCs through four routes including intraportal injection (InP group), hepatic intra-arterial injection (AH group), peripheral intravenous injection (PV group) and intrahepatic injection (IH group). The living conditions and survival time were recorded. Blood samples before and after MSCs transplantation were collected for the analysis of hepatic function. The histology of liver injury was interpreted and scored in terminal samples. Hepatic apoptosis was detected by TUNEL assay. Apoptosis and proliferation related protein expressions including cleaved caspase-3, survivin, AKT, phospho-AKT (Ser473), ERK and phospho-ERK (Tyr204) were analyzed by Western blotting.

RESULTS

The average survival time of each group was 10.7+/-1.6 days (InP), 6.0+/-0.9 days (AH), 4.7+/-1.4 days (PV), 4.3+/-0.8 days (IH), respectively, when compared with the average survival time of 3.8+/-0.8 days in the D-Gal group. The survival rates between the InP group and D-Gal group revealed a statistically significant difference (P<0.01). Pathological and biochemical analysis showed that liver damage was the worst in the D-Gal group, while less injury in the InP group. Histopathological scores revealed a significant decrease in the InP group (3.17+/-1.04, P<0.01) and AH group (8.17+/-0.76, P<0.05) as compared with that in the D-Gal group (11.50+/-1.32). The apoptosis rate in the InP group (25.0%+/-3.4%, P<0.01) and AH group (40.5%+/-1.0%, P<0.05) was lower than that in the D-Gal group (70.6%+/-8.5%). The expression of active caspase-3 was inhibited, while the expression of survivin, AKT, phospho-AKT (Ser473), ERK and phospho-ERK (Tyr204) was elevated in the InP group.

CONCLUSIONS

Intraportal injection was superior to other pathways for MSC transplantation. Intraportal MSC transplantation could improve liver function, inhibit apoptosis and prolong the survival time of swine with ALF. The transplanted MSCs may participate in liver regeneration via promoting cell proliferation and suppressing apoptosis during the initial stage of ALF.

Combined mesenchymal stem cell transplantation and interleukin-1 receptor antagonism after partial hepatectomy

AIM: To study the therapeutic effects of mesenchymal stem cells (MSCs) and an interleukin-1 receptor antagonist (IL-1Ra) in acute liver failure.

METHODS: Chinese experimental miniature swine (15 ± 3 kg, 5-8 mo) were obtained from the Laboratory Animal Centre of the Affiliated Drum Tower Hospital of Nanjing University Medical School. Acute liver failure was induced via 85% hepatectomy, and animals were treated by MSC transplantation combined with IL-1Ra injection. Blood samples were collected for hepatic function analysis, and the living conditions and survival time were recorded. Liver injury was histologically analyzed. Hepatic cell regeneration and apoptosis were studied by Ki67 immunohistochemistry and terminal deoxynucleotidyl transferase dUTP nick end labeling, respectively. The levels of protein kinase B and nuclear factor-κB expression were analyzed by Western blotting.

RESULTS: MSCs were infected with a lentivirus for expression of green fluorescent protein (GFP) for subsequent identification; 97.3% of the MSCs were positive for GFP as assessed by flow cytometry. Additional flow cytometric analysis of cell surface marker expression demonstrated that > 90% of GFP-expressing MSCs were also positive for CD29, CD44, and CD90, indicating that most of these cells expressed typical markers of MSCs, and the population of MSCs was almost pure. Transplantation of MSCs in combination with 2 mg/kg IL-1Ra therapy significantly improved survival time compared to the acute liver failure model group (35.3 ± 6.7 d vs 17.3 ± 5.5 d, P < 0.05). Combined therapy also promoted improvement in serum inflammatory cytokines and biochemical conditions. The observed hepatic histopathologic score was significantly lower in the group with combined therapy than in the model group (3.50 ± 0.87 vs 8.17 ± 1.26, P < 0.01). In addition, liver cell apoptosis in the combined therapy group was significantly inhibited (18.1 ± 2.1% vs 70.8 ± 3.7%, P < 0.01), and hepatic cell regeneration increased. A significant increase in protein kinase B expression and decrease in nuclear factor-κB expression were observed (P < 0.01), which supports their important roles in liver regeneration.

CONCLUSION: MSCs and IL-1Ra had a synergistic effect in liver regeneration via regulation of inflammation and apoptotic signaling.

The changing face of liver transplantation for acute liver failure: Assessment of current status and implications for future practice

The etiology and outcomes of acute liver failure (ALF) have changed since the definition of this disease entity in the 1970s. In particular, the role of emergency liver transplantation has evolved over time, with the development of prognostic scoring systems to facilitate listing of appropriate patients, and a better understanding of transplant benefit in patients with ALF. This review examines the changing etiology of ALF, transplant benefit, outcomes following transplantation, and future alternatives to emergency liver transplantation in this devastating condition.