Drug-Induced Acute Liver Failure

Reactive Oxygen Species Scavenging Nanozymes: Emerging Therapeutics for Acute Liver Injury Alleviation

Acute liver injury (AIL), a fatal clinical disease featured with a swift deterioration of hepatocyte functions in the short term, has emerged as a serious public health issues that warrants attention. However, the effectiveness of existing small molecular antioxidants and anti-inflammatory medications in alleviating AIL remains uncertain. The unique inherent structural characteristics of liver confer it a natural propensity for nanoparticle capture, which present an opportunity to exploit in the formulation of nanoscale therapeutic agents, enabling their selective accumulation in the liver and thereby facilitating targeted therapeutic interventions. Significantly increased reactive oxygen species (ROS) accumulation and inflammation response have been evidenced to play crucial roles in occurrence and development of AIL. Nanozymes with ROS-scavenging capacities have demonstrated considerable promise in ROS elimination and inflammation regulation, thereby offering an appealing therapeutic instrument for the management of acute liver injury. In this review, the mechanisms of different type of ALI were summarized. In addition, we provide a comprehensive summary and review of the available ROS-scavenging nanozymes, including transition metal-based nanozymes, noble metal nanozymes, carbon-based nanozymes, and some other nanozymes. Furthermore, the challenges still need to be solved in the field of ROS-scavenging nanozymes for ALI alleviation are also discussed.

Acute liver failure in low-income and middle-income countries

Acute liver failure is a rare condition involving the rapid development, progression, and worsening of liver dysfunction, characterised by coagulopathy and encephalopathy, and has a high mortality unless liver transplantation is performed. Population-based studies are scarce, and most published data are from high-income countries, where the main cause of acute liver failure is paracetamol overdose. This Review provides an overview of the scanty literature on acute liver failure in low-income and middle-income countries, where patients are often admitted to primary care hospitals and viral hepatitis (especially hepatitis E), tropical infections (eg, dengue), traditional medicines, and drugs (especially anti-tuberculosis drugs) have an important role. We discuss incidence, cause, occurrence in children and pregnant women, prognostic factors and scores, treatment, and mortality. To conclude, we advocate for international collaboration, the establishment of central registries for the condition, and better diagnostics.

Hepatoprotective effect and structural analysis of Hedysarum polysaccharides in vivo and in vitro

The crude Hedysarum polysaccharides (HPS: HPS-50 and HPS-80) obtained from Radix Hedysari exhibited great pharmacological activities in our previous research. This study investigated the effects of HPS on lipopolysaccharide (LPS)/D-galactosamine (D-GalN)-induced acute liver injury (ALI) in mice and LPS-induced injury in LO2 cells, as well as the relationship between structural characteristics and hepatoprotective activities. The in vivo results showed that compared with HPS-80, HPS-50 showed stronger hepatoprotection, which improved histopathological changes to normal levels. HPS-50 significantly decreased the levels of ALT, AST, MPO, and MDA, increased the activities of SOD, CAT, and GSH, and suppressed the LPS/D-GalN-triggered production of TNF-α, IL-1β, and IL-6 (p < .05). The results in vitro showed that HPS-50-P (HPS-50-1, HPS-50-2, and HPS-50-3) purified from HPS-50 played significant protective roles against LPS-induced injury in LO2 cells by reducing cell apoptosis and relieving cell cycle arrest. HPS-50-2 restored the percentage of normal cells from 54.8% to 94.7%, and reduced the S phase cells from 59.40% to 47.05% (p < .01). By analyzing the structure of HPS-50-P, including monosaccharide composition, molecular weight, chain conformation, and surface morphology, we speculated that the best protective effect of HPS-50-2 might be attributed to its beta configuration, highest molecular weight, and high glucose and galactose contents. These findings indicate that HPS-50 might be a promising source of functional foods for the protection and prevention of ALI. PRACTICAL APPLICATIONS: In this study, the protective effect of HPS on ALI was evaluated from multiple perspectives, and HPS-50-2 was screened as a potential active ingredient. This study has two practical applications. First, it provides a new way to improve ALI, and a new option for patients to prevent and treat ALI. Second, this work also complements the pharmacological activity of Radix Hedysari and provides a basis for the development of Radix Hedysari as a functional food.

Ferroptosis in liver disease: new insights into disease mechanisms

Characterized by excessive iron accumulation and lipid peroxidation, ferroptosis is a novel form of iron-dependent cell death, which is morphologically, genetically, and biochemically distinct from other well-known cell death. In recent years, ferroptosis has been quickly gaining attention in the field of liver diseases, as the liver is predisposed to oxidative injury and generally, excessive iron accumulation is a primary characteristic of most major liver diseases. In the current review, we first delineate three cellular defense mechanisms against ferroptosis (GPx4 in the mitochondria and cytosol, FSP1 on plasma membrane, and DHODH in mitochondria), along with four canonical modulators of ferroptosis (system Xc⁻, nuclear factor erythroid 2-related factor 2, p53, and GTP cyclohydrolase-1). Next, we review recent progress of ferroptosis studies delineating molecular mechanisms underlying the pathophysiology of several common liver diseases including ischemia/reperfusion-related injury (IRI), nonalcoholic fatty liver disease (NAFLD), alcoholic liver disease (ALD), hemochromatosis (HH), drug-induced liver injury (DILI), and hepatocellular carcinoma (HCC). Furthermore, we also highlight both challenges and promises that emerged from recent studies that should be addressed and pursued in future investigations before ferroptosis regulation could be adopted as an effective therapeutic target in clinical practice.

Safety of treating acute liver injury and failure

INTRODUCTION

Acute liver injury and progression to acute liver failure can be life-threatening conditions that require prompt careful clinical assessment and therapeutic management.

AREAS COVERED

The aim of this article is to review the safety and side effect profile of pharmacological therapies used in the treatment of acute liver injury with specific focus on hepatic toxicity. We performed an extensive literature search with the terms 'acute liver injury,' 'acute liver failure,' 'therapy,' 'safety,' 'adverse reactions' and 'drug induced liver injury.' A thorough discussion of the main drugs and devices used in patients with acute liver injury and acute liver failure, its safety profile and the management of complications associated to therapy of these conditions is presented.

EXPERT OPINION

Several pharmacological approaches are used in acute liver injury and acute liver failure in an empirical basis. Whilst steroids are frequently tried in serious drug-induced liver injury there is concern on a potential harmful effect of these agents because of the higher mortality in patients receiving the drug; hence, statistical approaches such as propensity score matching might help resolve this clinical dilemma. Likewise, properly designed clinical trials using old and new drugs for subjects with serious drug-induced liver injury are clearly needed.

Markedly elevated hepatic arterial velocity-HAV greater than 200 cm/s-is not specific to hepatobiliary disease

OBJECTIVE

The aim of the study was to review the different etiologies and outcomes of patients with hepatic artery velocities greater than 200 cm/s.

METHODS

This retrospective study included 88 hospitalized patients in whom angle-corrected proper hepatic artery flow velocities greater than 200 cm/s were obtained during an abdominal ultrasonographic examination. Peak systolic hepatic artery flow velocities, hepatic artery resistance index, and portal vein flow velocities were evaluated. The patients were then allocated to one of four groups based on their primary underlying diagnosis: structural liver disease, nonstructural liver disease, generalized infection, or miscellaneous.

RESULTS

The median hepatic artery velocity was similar for all groups, ranging from 226 to 238 cm/s. The maximum portal venous velocities were not significantly different between groups. No lab values were statistically different between the groups, except total bilirubin that was greater in the nonstructural liver disease group (8 mg/dL). Overall, 9/88 (10.2%) of patients with elevated hepatic artery velocity died within 30 days of their ultrasonographic examination.

CONCLUSION

Elevated hepatic artery velocity greater than 200 cm/s in hospitalized patients is not specific to primary hepatobiliary disease but may indicate acute hepatic dysfunction from other causes such as infection or sepsis.

Liver Transplant Due to Flupirtine-Induced Acute Liver Failure

OBJECTIVES

Acute drug-induced liver failure is a rare indication for liver transplant. There is only one case of flupirtine-induced liver failure requiring transplant in the literature. In February 2018, the European Medicines Agency issued a withdrawal of approval for flupirtine medication in European countries as a result of the risk of acute liver failure.

MATERIALS AND METHODS

The aim of this study was a German-wide collection of data regarding patients with liver transplant as a result of flupirtine-associated liver failure.

RESULTS

A total of 9 patients received transplants. All patients were women with a mean age of 43 years. Indication for flupirtine medication was musculoskeletal symptoms and migraine headache. The medication was taken over a period of approximately 3 months. All patients developed progressive acute liver failure, and no patient had previous chronic liver disease or cirrhosis. The mean laboratory Model for End Stage Liver Disease score for the patients was 31 ± 7 at time of transplant. Eight of the 9 patients were listed as "high urgency" for transplant. After transplant, they had an uneventful course with a prolonged mean intensive care unit stay of 13 ± 8.7 days. The whole hospitalization time was 43 ± 21 days.

CONCLUSIONS

This is the largest published series of patients who received liver transplant after a drug-induced acute liver failure from flupirtine medication.

Expansion of Transdifferentiated Human Hepatocytes in a Serum-Free Microcarrier Culture System

BACKGROUND AND AIMS

Bioartificial livers (BALs) have attracted much attention as potential supportive therapies for liver diseases. A serum-free microcarrier culture strategy for the in vitro high-density expansion of human-induced hepatocyte-like cells (hiHeps) suitable for BALs was studied in this article.

METHODS

hiHeps were transdifferentiated from human fibroblasts by the lentiviral overexpression of FOXA3, HNF1A, and HNF4A. Cells were cultured on microcarriers, their proliferation was evaluated by cell count and CCK-8 assays, and their function was evaluated by detecting liver function parameters in the supernatant, including urea secretion, albumin synthesis, and lactate dehydrogenase levels. The expressions of hepatocyte function-associated genes of hiHeps were measured by qRT-PCR in 2D and 3D conditions. The expression of related proteins during fibronectin promotes cell adhesion, and proliferation on microcarrier was detected by western blotting.

RESULTS

During microcarrier culture, the optimal culture conditions during the adherence period were the use of half-volume high-density inoculation, Cytodex 3 at a concentration of 3 mg/mL, a cell seeding density of 2.0 × 10⁵ cells/mL, and a stirring speed of 45 rpm. The final cell density in self-developed, chemically defined serum-free medium (SFM) reached 2.53 × 10⁶ cells/mL, and the maximum increase in expansion was 12.61-fold. In addition, we found that fibronectin (FN) can promote hiHep attachment and proliferation on Cytodex 3 microcarriers and that this pro-proliferative effect was mediated by the integrin-β1/FAK/ERK/CyclinD1 signaling pathway. Finally, the growth and function of hiHeps on Cytodex 3 in SFM were close to those of hiHeps on Cytodex 3 in hepatocyte maintenance medium (HMM), and cells maintained their morphology and function after harvest on microcarriers.

CONCLUSIONS

Serum-free microcarrier culture has important implications for the expansion of a sufficient number of hiHeps prior to the clinical application of BALs.

Idiosyncratic Drug-Induced Acute Liver Failure: A Challenging and Distressing Scenario

BACKGROUND

Idiosyncratic Drug Induced Liver Injury (DILI) is a rare adverse event to drugs that occasionally leads to severe liver damage, being one of the leading causes of Acute Liver Failure (ALF) in developed countries. DILI is largely a diagnosis of exclusion.

DISCUSSION AND CONCLUSION

Careful history of drug taking and ruling out other competing etiologies is mandatory given that DILI can present with an extremely variable phenotype. Several prognostic scores have been developed to promptly identify patients with potential risk of developing ALF. New biomarkers to diagnose and predict DILI evolution are under study and hopefully we will benefit from these novel tools in the near future.

Pathophysiology of Acute Liver Failure

Acute liver failure (ALF) is a rare syndrome resulting from an acute insult to the liver in patients without known underlying chronic liver disease. It is characterized by loss of synthetic function in the form of jaundice and coagulopathy and development of hepatic encephalopathy. Multiorgan failure (MOF) eventually develops, leading to death. Many different etiologies have been identified, with acetaminophen (APAP) overdose and viral hepatitis being the most common causes worldwide. The pathophysiology of ALF can be divided into cause-specific liver injury pathophysiologies and pathophysiology related to occurrence of secondary MOF. In terms of liver injury pathophysiology, APAP toxicity is the most well known. Secondary MOF is often a result of the initial massive proinflammatory response generating a systemic inflammatory response syndrome followed by a compensatory anti-inflammatory response leading to immune cell dysfunction and sepsis. As the liver is a tremendously important metabolic organ involved in energy metabolism, protein synthesis, fat metabolism, and glycemic control, multiple aspects of nutrition also need to be considered as part of the overall pathophysiology of ALF.

Resolution of Murine Toxic Hepatic Injury Quantified With Ultrasound Entropy Metrics

Image-based classification of liver disease generally lacks specificity for distinguishing between acute, resolvable injury and chronic irreversible injury. We propose that ultrasound radiofrequency data acquired in vivo from livers subjected to toxic drug injury can be analyzed with information theoretic detectors to derive entropy metrics, which classify a statistical distribution of pathologic scatterers that dissipate over time as livers heal. Here we exposed 38 C57BL/6 mice to carbon tetrachloride to cause liver damage, and imaged livers in vivo 1, 4, 8, 12 and 18 d after exposure with a broadband 15-MHz probe. Selected entropy metrics manifested monotonic recovery to normal values over time as livers healed, and were correlated directly with progressive restoration of liver architecture by histologic assessment (r² ≥ 0.95, p < 0.004). Thus, recovery of normal liver microarchitecture after toxic exposure can be delineated sensitively with entropy metrics.

Acute Liver Failure: From Textbook to Emergency Room and Intensive Care Unit With Concomitant Established and Modern Novel Therapies

Acute liver failure is a rare hepatic emergent situation that affects primarily young people and has often a catastrophic or even fatal outcome. Definition of acute liver failure has not reached a universal consensus and the interval between the appearance of jaundice and hepatic encephalopathy for the establishment of the acute failure is a matter of debate. Among the wide variety of causes, acetaminophen intoxication in western societies and viral hepatitis in the developing countries rank at the top of the etiology list. Identification of the clinical appearance and initial management for the stabilization of the patient are of vital significance. Further advanced therapies, that require intensive care unit, should be offered. The hallmark of treatment for selected patients can be orthotopic liver transplantation. Apart from well-established treatments, novel therapies like hepatocyte or stem cell transplantation, additional new therapeutic strategies targeting acetaminophen intoxication and/or hepatic encephalopathy are mainly experimental, and some of them do not belong, yet, to clinical practice. For clinicians, it is substantial to have the alertness to timely identify the patient and transfer them to a specialized center, where more treatment opportunities are available.

Carvedilol-Induced Liver Injury, a Rare Cause of Mixed Hepatitis: A Clinical Case

Introduction

Drug-induced liver injury is an increasingly prevalent consequence of the diversification of available therapeutic weapons, mostly idiosyncratic and with several possible mechanisms and patterns of specific damage for each drug. Carvedilol, a widely used non-selective alpha and beta blocker leads, in very rare cases, to injury of the bile ducts by toxic metabolites, resulting in a mixed-pattern hepatitis with possible progression to chronic cholestatic syndrome and cirrhosis. The authors report the second known case of this important toxicity.

Clinical Case

An 83-year-old woman was admitted to the Internal Medicine ward for etiological clarification of a mixed-pattern hepatitis. Clinical history was unremarkable and structural, infectious, and autoimmune causes were excluded by blood tests and imaging exams, ultimately leading to the diagnosis of toxic hepatitis that was further confirmed by liver biopsy with morphologic findings of mixed-pattern liver injury. Carvedilol, started 6 months before, was deemed the causal agent since it was the only drug with a clinically, temporally, analytically, and histologically compatible pattern. The withdrawal of the drug resulted in slow reversal of the referred abnormalities.

Conclusion

In very rare cases, carvedilol can cause important liver toxicity as a chronic cholestatic syndrome which can evolve to cirrhosis. It should be taken in consideration as causal agent in similar cases and stopped immediately upon suspicion, as the timely withdrawal results in reversion of the pathological findings.