Hepatic recruitment of myeloid-derived suppressor cells upon liver injury promotes both liver regeneration and fibrosis.

BACKGROUND: The liver regeneration is a highly complicated process depending on the close cooperations between the hepatocytes and non-parenchymal cells involving various inflammatory cells. Here, we explored the role of myeloid-derived suppressor cells (MDSCs) in the processes of liver regeneration and liver fibrosis after liver injury. METHODS: We established four liver injury models of mice including CCl4-induced liver injury model, bile duct ligation (BDL) model, concanavalin A (Con A)-induced hepatitis model, and lipopolysaccharide (LPS)-induced hepatitis model. The intrahepatic levels of MDSCs (CD11b+Gr-1+) after the liver injury were detected by flow cytometry. The effects of MDSCs on liver tissues were analyzed in the transwell co-culture system, in which the MDSCs cytokines including IL-10, VEGF, and TGF-ß were measured by ELISA assay and followed by being blocked with specific antibodies. RESULTS: The intrahepatic infiltrations of MDSCs with surface marker of CD11b+Gr-1+ remarkably increased after the establishment of four liver injury models. The blood served as the primary reservoir for hepatic recruitment of MDSCs during the liver injury, while the bone marrow appeared play a compensated role in increasing the number of MDSCs at the late stage of the inflammation. The recruited MDSCs in injured liver were mainly the M-MDSCs (CD11b+Ly6G-Ly6Chigh) featured by high expression levels of cytokines including IL-10, VEGF, and TGF-ß. Co-culture of the liver tissues with MDSCs significantly promoted the proliferation of both hepatocytes and hepatic stellate cells (HSCs). CONCLUSIONS: The dramatically and quickly infiltrated CD11b+Gr-1+ MDSCs in injured liver not only exerted pro-proliferative effects on hepatocytes, but also accounted for the activation of profibrotic HSCs.

Acute High-Output Heart Failure with Pulmonary Hypertension and Severe Liver Injury Caused by Amlodipine Poisoning: A Case Report.

Acute high-output heart failure (HOHF) with pulmonary hypertension and liver injury caused by amlodipine poisoning is very rare. We report a 52-year-old woman who suffered from severe shock after an overdose of amlodipine. Hemodynamic monitoring showed that while her left ventricular systolic function and cardiac output were elevated, her systemic vascular resistance decreased significantly. At the same time, the size of her right heart, her central venous pressure, and the oxygen saturation of her central venous circulation all increased abnormally. The patient's circulatory function and right ventricular dysfunction gradually improved after large doses of vasopressors and detoxification measures. However, her bilirubin and transaminase levels increased significantly on hospital day 6, with a CT scan showing patchy, low-density areas in her liver along with ascites. After liver protective treatment and plasma exchange, the patient's liver function gradually recovered. A CT scan 4 months later showed all her liver abnormalities, including ascites, had resolved. The common etiologies of HOHF were excluded in this case, and significantly reduced systemic vascular resistance caused by amlodipine overdose was thought to be the primary pathophysiological basis of HOHF. The significant increase in venous return and pulmonary blood flow is considered to be the main mechanism of right ventricular dysfunction and pulmonary hypertension. Hypoxic hepatitis caused by a combination of hepatic congestion and distributive shock may be the most important factors causing liver injury in this patient. Whether amlodipine has other mechanisms leading to HOHF and pulmonary hypertension needs to be further studied. Considering the significant increase of right heart preload, aggressive fluid resuscitation should be done very cautiously in patients with HOHF and shock secondary to amlodipine overdose.

Liver infiltration of multiple immune cells during the process of acute liver injury and repair.

BACKGROUND: Immune cells, including neutrophils, natural killer (NK) cells, T cells, NKT cells and macrophages, participate in the progression of acute liver injury and hepatic recovery. To date, there has been no systematic study on the quantitative changes in these different immune cells from initial injury to subsequent recovery. AIM: To investigate the infiltration changes of various immune cells in acute liver injury models over time, and to study the relationship between the changes in leukocyte cell-derived chemotaxin 2 (LECT2) and the infiltration of several immune cells. METHODS: Carbon tetrachloride- and concanavalin A-induced acute liver injury models were employed to mimic toxin-induced and autoimmune-mediated liver injury respectively. The quantitative changes in various immune cells were monitored at different time points. Serum samples were collected, and liver tissues were harvested. Ly6G, CD161, CD4, CD8 and F4/80 staining were used to indicate neutrophils, NK/NKT cells, CD4+ T cells, CD8+ T cells and macrophages, respectively. Lect2-KO mice were used to detect the function of LECT2. RESULTS: During the injury and repair process, different types of immune cells began to increase, reached their peaks and fell into decline at different time points. Furthermore, when the serum alanine transaminase (ALT) and aspartate transaminase (AST) indices reverted to normal levels 7 d after the injury, the infiltration of immune cells still existed even 14 d after the injury, showing an obvious lag effect. We found that the expression of LECT2 was upregulated in acute liver injury mouse models, and the liver injuries of Lect2-KO mice were less severe than those of wild-type mice. Compared with wild-type mice, Lect2-KO mice had different immune cell infiltration. CONCLUSION: The recovery time of immune cells was far behind that of serum ALT and AST during the process of liver repair. LECT2 could regulate monocyte/macrophage chemotaxis and might be used as a therapeutic target for acute liver injury.

Metabolomic Analysis Reveals the Mechanisms of Hepatotoxicity Induced by Aflatoxin M1 and Ochratoxin A.

Aflatoxin M1 (AFM1) is the only toxin with the maximum residue limit in milk, and ochratoxin A (OTA) represents a common toxin in cereals foods. It is common to find the co-occurrence of these two toxins in the environment. However, the interactive effect of these toxins on hepatoxicity and underlying mechanisms is still unclear. The liver and serum metabolomics in mice exposed to individual AFM1 at 3.5 mg/kg b.w., OTA at 3.5 mg/kg b.w., and their combination for 35 days were conducted based on the UPLC-MS method in the present study. Subsequent metabolome on human hepatocellular liver carcinoma (Hep G2) cells was conducted to narrow down the key metabolites. The phenotypic results on liver weight and serum indicators, such as total bilirubin and glutamyltransferase, showed that the combined toxins had more serious adverse effects than an individual one, indicating that the combined AFM1 and OTA displayed synergistic effects on liver damage. Through the metabolic analysis in liver and serum, we found that (i) a synergistic effect was exerted in the combined toxins, because the number of differentially expressed metabolites on combination treatment was higher than the individual toxins, (ii) OTA played a dominant role in the hepatoxicity induced by the combination of AFM1, and OTA and (iii) lysophosphatidylcholines (LysoPCs), more especially, LysoPC (16:1), were identified as the metabolites most affected by AFM1 and OTA. These findings provided a new insight for identifying the potential biomarkers for the hepatoxicity of AFM1 and OTA.

ExoU Induces Lung Endothelial Cell Damage and Activates Pro-Inflammatory Caspase-1 during Pseudomonas aeruginosa Infection.

The Gram-negative, opportunistic pathogen Pseudomonas aeruginosa utilizes a type III secretion system to inject exoenzyme effectors into a target host cell. Of the four best-studied exoenzymes, ExoU causes rapid cell damage and death. ExoU is a phospholipase A2 (PLA2) that hydrolyses host cell membranes, and P. aeruginosa strains expressing ExoU are associated with poor outcomes in critically ill patients with pneumonia. While the effects of ExoU on lung epithelial and immune cells are well studied, a role for ExoU in disrupting lung endothelial cell function has only recently emerged. Lung endothelial cells maintain a barrier to fluid and protein flux into tissue and airspaces and regulate inflammation. Herein, we describe a pulmonary microvascular endothelial cell (PMVEC) culture infection model to examine the effects of ExoU. Using characterized P. aeruginosa strains and primary clinical isolates, we show that strains expressing ExoU disrupt PMVEC barrier function by causing substantial PMVEC damage and lysis, in a PLA2-dependent manner. In addition, we show that strains expressing ExoU activate the pro-inflammatory caspase-1, in a PLA2-dependent manner. Considering the important roles for mitochondria and oxidative stress in regulating inflammatory responses, we next examined the effects of ExoU on reactive oxygen species production. Infection of PMVECs with P. aeruginosa strains expressing ExoU triggered a robust oxidative stress compared to strains expressing other exoenzyme effectors. We also provide evidence that, intriguingly, ExoU PLA2 activity was detectable in mitochondria and mitochondria-associated membrane fractions isolated from P. aeruginosa-infected PMVECs. Interestingly, ExoU-mediated activation of caspase-1 was partially inhibited by reactive oxygen species scavengers. Together, these data suggest ExoU exerts pleiotropic effects on PMVEC function during P. aeruginosa infection that may inhibit endothelial barrier and inflammatory functions.

Analysis of the clinical characteristics of the liver injury induced by levetiracetam.

OBJECTIVES: Levetiracetam (LEV) has a low risk of hepatotoxicity due to low liver metabolism. Knowledge regarding the association between LEV exposure and liver injury is based mainly on case reports. The purpose of this study is to summarize the clinical features of LEV-induced liver injury. METHODS: We collected literature on liver injury induced by LEV for retrospective analysis from 1999 to April 2021 in Chinese and English. KEY FINDINGS: The median age of 21 patients (13 males and 8 females) was 31 years (range 0.13-76). The median time for liver injury was 19 days (range 3-120). The clinical manifestations of patients ranged from asymptomatic elevated liver enzymes in 5 patients (23.8%) to fever, digestive system symptoms and skin rash in 16 patients (76.2%). The median values of alanine aminotransferase and aspartate aminotransferase were 773 IU/L (range 60-4800) and 667.5 IU/L (range 53-10 387), respectively. Liver biopsy demonstrated hepatocellular necrosis. The liver function returned to normal at a median time of 9 days (range 2-270) after discontinuation of LEV. CONCLUSIONS: LEV-induced liver injury is a rare adverse reaction, ranging from asymptomatic elevated transaminases to fulminant liver failure. Patients receiving long-term treatment with LEV should consider monitoring liver function.

Long-term sequelae of drug-induced liver injury.

Drug-induced liver injury (DILI) has a very variable clinical and biochemical phenotype and differs widely in severity, from mild injury to life-threatening liver failure. Chronic injury has also been reported to occur at a variable frequency, ranging from 3.4% to 39%, 6-12 months after discontinuing the implicated agent. This wide range is probably related to various definitions of chronic liver injury and variable selection of patients. The long-term sequalae of this chronic injury in terms of morbidity and mortality are unclear, although rare vanishing bile duct syndrome is associated with an unfavourable prognosis, with increased risk of chronic liver failure and need for liver transplantation. Other forms of long-term sequalae associated with DILI are progressive fibrosis, autoimmune-like hepatitis, secondary sclerosing cholangitis, sinusoidal obstruction syndrome and, as a common final stage, the development of cirrhosis, portal hypertension and its complications. Immune checkpoint inhibitors, which can cause an autoimmune-like phenotype have also recently been shown to cause sclerosing cholangitis with cytotoxic T CD8+ cell infiltration in biliary tracts. DILI has been shown to have a significant impact on health-related quality of life but very little is known about its psychological consequences in the long-term. Further investigations with structured long-term follow-up and periodic quality of life surveys are needed to assess the impact of DILI on psychological outcomes, particularly in those with chronic sequelae.

Aurantio-obtusin induces hepatotoxicity through activation of NLRP3 inflammasome signaling.

Aurantio-obtusin (AO) is a major anthraquinone (AQ) compound derived from Cassiae semen (CS). Although pharmacological studies have shown that the CS extracts can serve as effective agents in preclinical and clinical practice, AQ-induced hepatotoxicity in humans has attracted widespread attention. To explore whether AO induces hepatotoxicity and its underlying mechanisms, we exposed larval zebrafish and mice to AO. We found that AO delayed yolk sac absorption, and increased liver area and inflammation in the larval zebrafish. This inflammation was manifested as an increase in liver neutrophils and the up-regulated mRNA expression of interleukin-6 (Il-6) and tumor necrosis factor-α (Tnf-α) in the larval zebrafish. Furthermore, a pharmacokinetics study showed that AO was quickly absorbed into the blood and rapidly metabolized in the mice. Of note, AO induced hepatotoxicity in a gender-dependent manner, characterized by liver dysfunction, increased hepatocyte necrosis with inflammatory infiltration, and up-regulated mRNAs of Il-6, Tnf-α and monocyte chemotactic protein 1(Mcp1) in the female mice after 28-day oral administration. It also highlighted that AO triggered NOD-like receptor protein (NLRP) signaling in the female mice, as evidenced by the increased NLRP3, Caspase-1, pro-IL-1ß, IL-1ß and IL-18. Finally, we found that AO led to a significant increase in potassium calcium-activated channel, subfamily N, member 4 (KCNN4) and reactive oxygen species (ROS) levels, along with decreased nuclear factor kappa B p65 (NF-κB p65), in the female mouse livers. In conclusion, AO induced hepatotoxicity by activating NLRP3 inflammasome signaling, at least in part, through increased KCNN4 and ROS production, and NF-κB inhibition.

Decision tree outcome prediction of acute acetaminophen exposure in the United States: A study of 30,000 cases from the National Poison Data System.

Acetaminophen is one of the most commonly used analgesic drugs in the United States. However, the outcomes of acute acetaminophen overdose might be very serious in some cases. Therefore, prediction of the outcomes of acute acetaminophen exposure is crucial. This study is a 6-year retrospective cohort study using National Poison Data System (NPDS) data. A decision tree algorithm was used to determine the risk predictors of acetaminophen exposure. The decision tree model had an accuracy of 0.839, an accuracy of 0.836, a recall of 0.72, a specificity of 0.86 and an F1_score of 0.76 for the test group and an accuracy of 0.848, a recall of 0.85, a recall of 0.74, a specificity of 0.87 and an F1_score of 0.78 for the training group. Our results showed that elevated serum levels of liver enzymes, other liver function test abnormality, anorexia, acidosis, electrolyte abnormality, increased bilirubin, coagulopathy, abdominal pain, coma, increased anion gap, tachycardia and hypotension were the most important factors in determining the outcome of acute acetaminophen exposure. Therefore, the decision tree model is a reliable approach in determining the prognosis of acetaminophen exposure cases and can be used in an emergency room or during hospitalization.

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.

25-Hydroxycholesterol 3-Sulfate Recovers Acetaminophen Induced Acute Liver Injury via Stabilizing Mitochondria in Mouse Models.

Acetaminophen (APAP) overdose is one of the most frequent causes of acute liver failure (ALF). N-acetylcysteine (NAC) is currently being used as part of the standard care in the clinic but its usage has been limited in severe cases, in which liver transplantation becomes the only treatment option. Therefore, there still is a need for a specific and effective therapy for APAP induced ALF. In the current study, we have demonstrated that treatment with 25-Hydroxycholesterol 3-Sulfate (25HC3S) not only significantly reduced mortality but also decreased the plasma levels of liver injury markers, including LDH, AST, and ALT, in APAP overdosed mouse models. 25HC3S also decreased the expression of those genes involved in cell apoptosis, stabilized mitochondrial polarization, and significantly decreased the levels of oxidants, malondialdehyde (MDA), and reactive oxygen species (ROS). Whole genome bisulfite sequencing analysis showed that 25HC3S increased demethylation of 5mCpG in key promoter regions and thereby increased the expression of those genes involved in MAPK-ERK and PI3K-Akt signaling pathways. We concluded that 25HC3S may alleviate APAP induced liver injury via up-regulating the master signaling pathways and maintaining mitochondrial membrane polarization. The results suggest that 25HC3S treatment facilitates the recovery and significantly decreases the mortality of APAP induced acute liver injury and has a synergistic effect with NAC in propylene glycol (PG) for the injury.

Ochratoxin A Induces Steatosis via PPARγ-CD36 Axis.

Ochratoxin A(OTA) is considered to be one of the most important contaminants of food and feed worldwide. The liver is one of key target organs for OTA to exert its toxic effects. Due to current lifestyle and diet, nonalcoholic fatty liver disease (NAFLD) has been the most common liver disease. To examine the potential effect of OTA on hepatic lipid metabolism and NAFLD, C57BL/6 male mice received 1 mg/kg OTA by gavage daily. Compared with controls, OTA increased lipid deposition and TG accumulation in mouse livers. In vitro OTA treatment also promoted lipid droplets accumulation in primary hepatocytes and HepG2 cells. Mechanistically, OTA prevented PPARγ degradation by reducing the interaction between PPARγ and its E3 ligase SIAH2, which led to activation of PPARγ signaling pathway. Furthermore, downregulation or inhibition of CD36, a known of PPARγ, alleviated OTA-induced lipid droplets deposition and TG accumulation. Therefore, OTA induces hepatic steatosis via PPARγ-CD36 axis, suggesting that OTA has an impact on liver lipid metabolism and may contribute to the development of metabolic diseases.

2-Amino-3-Methylimidazo[4,5-f]quinoline Triggering Liver Damage by Inhibiting Autophagy and Inducing Endoplasmic Reticulum Stress in Zebrafish (Danio rerio).

It is important to note that 2-Amino-3-methylimidazole[4,5-f]quinoline (IQ) is one of the most common heterocyclic amines (HCAs), which is a class of mutagenic/carcinogenic harmful compounds mainly found in high-protein thermal processed foods and contaminated environments. However, the pre-carcinogenic toxicity of IQ to the liver and its mechanism are poorly understood, further research is needed. In light of this, we exposed zebrafish to IQ (0, 8, 80, and 800 ng/mL) for 35 days, followed by comprehensive experimental studies. Histopathological and ultrastructural analysis showed that hepatocytes were damaged. TUNEL results showed that IQ induced apoptosis of liver cells, the expression of apoptosis factor gene was significantly increased, and the expression of Bcl-2 protein was significantly decreased. In addition, upregulated expression of the 78-kDa glucose-regulated protein (GRP78) and C/EBP homologous protein (CHOP) and endoplasmic reticulum stress (ERS)-related factors transcription levels were elevated obviously, suggesting that IQ induced ERS. Decreased protein expression of autophagy-related 5 (Atg5)-Atg12, Beclin1, and LC3-II, increased protein expression of p62, and autophagy-related factors transcription levels were significantly decreased, suggesting that IQ inhibited autophagy. Overall, our research showed that the potential harm of IQ to the liver before the occurrence of liver cancer was related to ERS and its mediated autophagy and apoptosis pathways.

Insight into the practical models for prediciting the essential role of the cytochrome P450-mediated biotransformation in emodin-associated hepatotoxicity.

Emodin is widely present in Chinese herbs with broad application prospects, however, the conflicting reports of its hepatotoxicity have created a concern. It was therefore aimed to develop practical models to elucidate the outcome of CYP450 biotransformation on emodin. HepG2 and rat liver microsomes (RLM) coculture system was first utilized for prediction. It was found that emodin (35 µM)-mediated cytotoxicity was alleviated only when the cofactor of CYP450 NADPH (1 mM) was present. Similarly, both the pan-CYP450 inhibitor 1-aminobenzotriazole (ABT) (2 mM) and the heat-inactivated liver microsomes completely abolished the protective effect of RLM (0.75 mg/mL). Consistently, ABT significantly increased the toxicity of emodin in primary rat liver cells. Along similar lines, only the monohydroxylation metabolite M3 that accounted for neglectable amount of the whole metabolites showed similar toxicity to emodin, both M1 and M2 exhibited far less toxcity than emodin in THLE-2 cells. In vivo study further supported that ABT (50 mg/kg, s.c.) aggravated the hepatotoxicity of emodin (80 mg/kg, i.p.) on mice, as emodin treatment only mediated slight increase of liver index and histological score likely due to the metabolic detoxication of emodin, whereas ABT co-administration resulted in severe liver injury as reflected by the dramatic increase of the liver index value, serum ALT and AST levels, and histopathological score. Moreover, it was explored that ROS generation together with the electrophilicity of emodin contributed to its hepatotoxicity. These findings not only provided a clear evidence of the metabolic detoxification of emodin, but also shed a light on the hepatotoxic mechanisms of emodin, which would lay a solid foundation for the rational application of emodin in the future.

Nickel nanoparticles induce hepatotoxicity via oxidative and nitrative stress-mediated apoptosis and inflammation.

Nickel nanoparticles (Ni NPs) are utilized extensively in various industrial applications. However, there are increasing concerns about potential exposure to Ni NPs and consequent health effects. The aim of this study was to assess Ni NPs-induced liver toxicity in Sprague Dawley rats. Twenty-five rats were exposed to Ni NPs via intraperitoneal injection at doses of 15, 30, and 45 mg/kg per body weight for 28 days. Results from ICP-MS analysis showed an increase in the concentration of Ni NPs in a dose-dependent manner. The liver dysfunction was indicated by considerable production of ALT, AST, ALP, LDH, and TB in Ni NPs-treated rats. Histological examination demonstrated liver injuries (inflammatory cells, congestion, necrosis, and pyknosis) in exposed rats with dose-dependent severity of pathologies by semi-quantitative histograding system. To explore the toxicological pathways, we examined oxidative stress biomarkers and detected Ni NPs significantly elevated the levels of MDA and LPO while decreasing the levels of CAT and GSH. All the changes in biomarkers were recorded in a dose-dependent relationship. In addition, we found upregulated NF-kß indicating activation of inflammatory cytokines. ELISA results of serum revealed a remarkable increase of nitrative stress markers (iNOS and NO), ATPase activity, inflammatory cytokine (IL-6, IL-1ß, and TNF-α), and apoptotic mediators (caspase-3 and caspase-9) in Ni NPs-treated groups than the control. In summary, the result of this study provided evidence of hepatotoxicity of Ni NPs and insightful information about the involved toxic pathways, which will help in health risk assessment and management, related preventive measures for the use of Ni-NPs materials.

Lenvatinib exposure induces hepatotoxicity in zebrafish via inhibiting Wnt signaling.

Lenvatinib is a multi-kinase inhibitor for widely treating thyroid cancer. However, little studies have been done about it or its toxicity on embryonic development of vertebrate. In this study, we used zebrafish to assess the effect of lenvatinib on early embryonic development. Exposure of zebrafish embryos to 58, 117, 176 nM lenvatinib induced abnormal embryonic development, such as decreased heart rate, pericardial edema, delayed yolk absorption, and bladder atrophy. Lenvatinib exposure reduced liver area and down-regulated liver developmental related genes. The proliferation of hepatocytes and the expression of apoptosis-related genes were significantly reduced.by Lenvatinib. Furthermore, the imbalance of liver metabolism and abnormal liver tissue structure were observed in adult zebrafish after Lenvatinib exposure. Oxidative stress was up-regulated by lenvatinib and astaxanthin partially rescued hepatic developmental defects via downregulating oxidative stress. After lenvatinib exposure, Wnt signaling was down-regulated, and activation of Wnt signaling partially rescued hepatic developmental defects. Therefore, these results suggested that lenvatinib might induce zebrafish hepatotoxicity by down-regulating Wnt signaling related genes and inducing oxidative stress. This study provides a reference for the potential hepatotoxicity of lenvatinib during embryonic development and raises health concern about the potential harm of exposure to lenvatinib for foetuses.

Human-relevant mechanisms and risk factors for TAK-875-Induced liver injury identified via a gene pathway-based approach in Collaborative Cross mice.

Development of TAK-875 was discontinued when a small number of serious drug-induced liver injury (DILI) cases were observed in Phase 3 clinical trials. Subsequent studies have identified hepatocellular oxidative stress, mitochondrial dysfunction, altered bile acid homeostasis, and immune response as mechanisms of TAK-875 DILI and the contribution of genetic risk factors in oxidative response and mitochondrial pathways to the toxicity susceptibility observed in patients. We tested the hypothesis that a novel preclinical approach based on gene pathway analysis in the livers of Collaborative Cross mice could be used to identify human-relevant mechanisms of toxicity and genetic risk factors at the level of the hepatocyte as reported in a human genome-wide association study. Eight (8) male mice (4 matched pairs) from each of 45 Collaborative Cross lines were treated with a single oral (gavage) dose of either vehicle or 600 mg/kg TAK-875. As expected, liver injury was not detected histologically and few changes in plasma biomarkers of hepatotoxicity were observed. However, gene expression profiling in the liver identified hundreds of transcripts responsive to TAK-875 treatment across all strains reflecting alterations in immune response and bile acid homeostasis and the interaction of treatment and strain reflecting oxidative stress and mitochondrial dysfunction. Fold-change expression values were then used to develop pathway-based phenotypes for genetic mapping which identified candidate risk factor genes for TAK-875 toxicity susceptibility at the level of the hepatocyte. Taken together, these findings support our hypothesis that a gene pathway-based approach using Collaborative Cross mice could inform sensitive strains, human-relevant mechanisms of toxicity, and genetic risk factors for TAK-875 DILI. This novel preclinical approach may be helpful in understanding, predicting, and ultimately preventing clinical DILI for other drugs.

Decrease in acetyl-CoA pathway utilizing butyrate-producing bacteria is a key pathogenic feature of alcohol-induced functional gut microbial dysbiosis and development of liver disease in mice.

Emerging research evidence has established the critical role of the gut-liver axis in the development of alcohol-associated liver disease (ALD). The present study employed 16S rRNA gene and whole genome shotgun (WGS) metagenomic analysis in combination with a revised microbial dataset to comprehensively detail the butyrate-producing microbial communities and the associated butyrate metabolic pathways affected by chronic ethanol feeding. Specifically, the data demonstrated that a decrease in several butyrate-producing bacterial genera belonging to distinct families within the Firmicutes phyla was a significant component of ethanol-induced dysbiosis. WGS analysis of total bacterial genomes encompassing butyrate synthesizing pathways provided the functional characteristics of the microbiome associated with butyrate synthesis. The data revealed that in control mice microbiome, the acetyl-coenzyme A (CoA) butyrate synthesizing pathway was the most prevalent and was significantly and maximally decreased by chronic ethanol feeding. Further WGS analysis i) validated the ethanol-induced decrease in the acetyl-CoA pathway by identifying the decrease in two critical genes but - (butyryl-CoA: acetate CoA transferase) and buk - (butyrate kinase) that encode the terminal condensing enzymes required for converting butyryl-CoA to butyrate and ii) detection of specific taxa of butyrate-producing bacteria containing but and buk genes. Notably, the administration of tributyrin (Tb) - a butyrate prodrug - significantly prevented ethanol-induced decrease in butyrate-producing bacteria, hepatic steatosis, inflammation, and injury. Taken together, our findings strongly suggest that the loss of butyrate-producing bacteria using the acetyl-CoA pathway is a significant pathogenic feature of ethanol-induced microbial dysbiosis and ALD and can be targeted for therapy.

Metabolomic analysis to discriminate drug-induced liver injury (DILI) phenotypes.

Drug-induced liver injury (DILI) is an adverse toxic hepatic clinical reaction associated to the administration of a drug that can occur both at early clinical stages of drug development, as well after normal clinical usage of approved drugs. Because of its unpredictability and clinical relevance, it is of medical concern. Three DILI phenotypes (hepatocellular, cholestatic, and mixed) are currently recognized, based on serum alanine aminotransferase (ALT) and alkaline phosphatase (ALP) values. However, this classification lacks accuracy to distinguish among the many intermediate mixed types, or even to estimate the magnitude and progression of the injury. It was found desirable to have additional elements for better evaluation criteria of DILI. With this aim, we have examined the serum metabolomic changes occurring in 79 DILI patients recruited and monitored using established clinical criteria, along the course of the disease and until recovery. Results revealed that free and conjugated bile acids, and glycerophospholipids were among the most relevant metabolite classes for DILI phenotype characterization. Using an ensemble of PLS-DA models, metabolomic information was integrated into a ternary diagram to display the disease phenotype, the severity of the liver damage, and its progression. The modeling implemented and the use of such compiled information in an easily understandable and visual manner facilitates a straightforward DILI phenotyping and allow to monitor its progression and recovery prediction, usefully complementing the concise information drawn out by the ALT and ALP classification.

The Disease-Modifying Therapies of Relapsing-Remitting Multiple Sclerosis and Liver Injury: A Narrative Review.

In this narrative review, we analyze pre-registration and post-marketing data concerning hepatotoxicity of all disease-modifying therapies (DMTs) available for the treatment of relapsing-remitting multiple sclerosis, including beta interferon, glatiramer acetate, fingolimod, teriflunomide, dimethyl fumarate, cladribine, natalizumab, alemtuzumab, and ocrelizumab. We review the proposed causal mechanisms described in the literature and we also address issues like use of DMTs in patients with viral hepatitis or liver cirrhosis. Most data emerged in the post-marketing phase by reports to national pharmacovigilance agencies and published case reports or case series. Serious liver adverse events are rare, but exact incidence is largely unknown, as are predictive factors. Unfortunately, none of the DMTs currently available for the treatment of multiple sclerosis is free of potential hepatic toxic effects. Cases of acute liver failure have been reported for beta-interferon, fingolimod, natalizumab, alemtuzumab, and ocrelizumab by different mechanisms (idiosyncratic reaction, autoimmune hepatitis, or viral reactivation). Patients with multiple sclerosis should be informed about possible hepatic side effects of their treatment. Most cases of liver injury are idiosyncratic and unpredictable. The specific monitoring schedule for each DMT has been reviewed and the clinician should be ready to recognize clinical symptoms suggestive for liver injury. Not all DMTs are indicated in cirrhotic patients. For some DMTs, screening for hepatitis B virus and hepatitis C virus is required before starting treatment and a monitoring or antiviral prophylaxis schedule has been established. Beta interferon, glatiramer acetate, natalizumab, and alemtuzumab are relatively contraindicated in autoimmune hepatitis due to the risk of disease exacerbation.

Many disease-modifying therapies (DMTs) are approved for multiple sclerosis treatment, but liver injury is a concern. Patients can experience transaminase elevation during DMT treatment, and in rare cases, idiosyncratic and unpredictable acute liver failure. Currently, it is not possible to predict or prevent serious liver-related adverse events. Furthermore, autoimmune hepatitis and viral reactivation can also occur during DMT treatments. Since adverse events are greatly underreported, it is important to report cases of serious liver-related adverse events in the literature with adequate causality documentation to better understand the liver safety profiles of DMTs.