Induction Of Acute Liver Injury Research Articles

The Protective Effect of Roflumilast Against Acute Hepatotoxicity Caused by Methotrexate in Wistar Rats: In vivo Evaluation.

Methotrexate (MTX) is one of the most widely used drugs in cancer chemotherapy and treating rheumatoid arthritis. The hepatotoxicity of MTX is one of its major side effects. Roflumilast (ROF) has been recognized to have antioxidant and anti-inflammatory activity in in-vivo and in-vitro models. The present study aimed to explore the potential protective effects of roflumilast against MTX-induced liver toxicity in male Wistar rats. High dose of 5 mg/kg for 4 consecutive days subcutaneous (S.C) injection of methotrexate for induction of acute liver injury. A total of 24 Wistar rats, rats were used in four different groups. The NS injections were given S.C to the control group once a day for 4 consecutive days. SC injections of MTX (5 mg/kg) were given to the MTX group daily for four days. At 5 mg/kg once daily for four days, the roflumilast group was given daily oral roflumilast. An injection of MTX and oral roflumilast were given to the MTX + roflumilast group once daily for four consecutive days. Administration of high dose MTX (5 mg/kg) today 4 produced a significant decrease in hepatic glutathione (GSH) levels and a significant increase in ALT and AST liver enzymes, hepatic malondialdehyde (MDA), tumor suppressor protein (p53), interleukin 6, interleukin 1 levels compared to the control group. Treatment with roflumilast for 4 days significantly attenuated unfavorable changes in these parameters. According to histopathological findings, Roflumilast significantly reduced MTX-induced inflammation and degeneration in the liver. In conclusion, the findings indicate that roflumilast may have a potential therapeutic benefit in treating rats with MTX-induced liver toxicity by mitigating its effects. The aim of this study is to investigate the potential protective effects of roflumilast against MTX-induced liver toxicity in Wistar rats.

Resolvin D1 promotes the resolution of inflammation in the ACLF rat model by increasing the proportion of Treg cells.

Acute-on-chronic liver failure (ACLF) causes organ system failures in patients and increases the risk of mortality. One of the main predictors of ACLF development in patients is the severity of systemic inflammation. The purpose of this study was to explore the effects of resolvin D1 (RvD1) on the rat model of ACLF. The ACLF rats were induced by firstintraperitoneally (ip) injecting CCl4 and porcine serum for 6 weeks to establish the chronic liver injury, followed by once administration (ip) of lipopolysaccharide and d-galactose d-GalN to cause acute liver injury (ALI). An hour before the ALI-induced treatment, rats were administrated (ip) with 0.9% saline or different doses of RvD1 (0.3 or 1 µg/kg). Afterward, the control and treated rats were killed and samples were collected. Biochemical analysis, hematoxylin-eosin and Sirius red staining, flow cytometry assay, and real-time polymerase chain reaction were used to assess the rat liver histopathological injury, the percentage of Treg cells in the spleen, and the messenger RNA (mRNA) levels of transcription factors and immunologic cytokines in liver. The necroinflammatory scores and the serum levels of transaminase significantly increased in ACLF rats compared with those in control rats. These impaired changes observed in ACLF rats could be attenuated by the administration of a low dose of RvD1 before the induction of ALI, which was associated with the increased proportion of regulatory T cells (Treg)in the spleen together with the increased gene expression ratio of Foxp3/RORγt and decreased mRNA level of Il-17a and Il-6 in the liver. A low dose of RvD1 can promote the resolution of inflammation in ACLF rats by increasing the proportion of Treg cells. RvD1, therefore, may be used as a potential drug for the treatment of patients with ACLF.

Preventing acute liver injury via hepatocyte-targeting nano-antioxidants.

Acute liver injury (ALI) is a severe liver disease that is characterized by sudden and massive hepatocyte necrosis and deterioration of liver functions. Oxidative stress is increasingly recognized as a key factor in the induction and progression of ALI. Scavenging excessive reactive oxygen species (ROS) with antioxidants has become a promising therapeutic option, but intrinsically hepatocyte-targeting antioxidants with excellent bioavailability and biocompatibility are yet to be developed. Herein, self-assembling nanoparticles (NPs) composed of amphiphilic polymers are introduced to encapsulate organic Selenium compound L-Se-methylselenocysteine (SeMC) and form SeMC NPs, which protect the viabilities and functions of cultured hepatocytes in drug- or chemical-induced acute hepatotoxicity models via efficient ROS removal. After further functionalization with the hepatocyte-targeting ligand glycyrrhetinic acid (GA), the resultant GA-SeMC NPs exhibit enhanced hepatocyte uptake and liver accumulation. In mouse models of ALI induced by acetaminophen (APAP) or carbon tetrachloride (CCl4 ), treatment with GA-SeMC NPs significantly decrease the levels of hepatic lipid peroxidation, tissue vacuolization and serum liver transaminases, while prominently increase that of endogenous antioxidant enzymes. Our study therefore presents a liver-targeting drug delivery strategy for the prevention and treatment of hepatic diseases.

Probiotic Lactobacillus casei Shirota prevents acute liver injury by reshaping the gut microbiota to alleviate excessive inflammation and metabolic disorders.

SummaryMillions of people die from liver diseases annually, and liver failure is one of the three major outcomes of liver disease. The gut microbiota plays a crucial role in liver diseases. This study aimed to explore the effects of Lactobacillus casei strain Shirota (LcS), a probiotics used widely around the world, on acute liver injury (ALI), as well as the underlying mechanism. Sprague Dawley rats were intragastrically administered LcS suspensions or placebo once daily for 7 days before induction of ALI by intraperitoneal injection of D‐galactosamine (D‐GalN). Histopathological examination and assessments of liver biochemical markers, inflammatory cytokines, and the gut microbiota, metabolome and transcriptome were conducted. Our results showed that pretreatment with LcS reduced hepatic and intestinal damage and reduced the elevation of serum gamma‐glutamyltranspeptidase (GGT), total bile acids, IL‐5, IL‐10, G‐CSF and RANTES. The analysis of the gut microbiota, metabolome and transcriptome showed that LcS lowered the ratio of Firmicutes to Bacteroidetes; reduced the enrichment of metabolites such as chenodeoxycholic acid, deoxycholic acid, lithocholic acid, d‐talose and N‐acetyl‐glucosamine, reduce the depletion of d‐glucose and l‐methionine; and alleviated the downregulation of retinol metabolism and PPAR signalling and the upregulation of the pyruvate metabolism pathway in the liver. These results indicate the promising prospect of using LcS for the treatment of liver diseases, particularly ALI.

Drug-induced-acute liver failure: A critical appraisal of the thioacetamide model for the study of hepatic encephalopathy.

Hepatic encephalopathy (HE) following acute and chronic liver failure is defined as a complex of neuropsychiatric abnormalities, such as discrete personal changes, sleep disorder, forgetfulness, confusion, and decreasing the level of consciousness to coma. The use and design of suitable animal models that represent clinical features and pathological changes of HE are valuable to map the molecular mechanisms that result in HE. Among different types of animal models, thioacetamide (TAA) has been used extensively for the induction of acute liver injury and HE. This agent is not directly hepatotoxic but its metabolites induce liver injury through the induction of oxidative stress and produce systemic inflammation similar to that seen in acute HE patients. In this short review article, we shortly review the most important pathological findings in animal models of acute HE following the administration of TAA.

Polydeoxyribonucleotide Exerts Protective Effect Against CCl4-Induced Acute Liver Injury Through Inactivation of NF-κB/MAPK Signaling Pathway in Mice

Acute liver injury (ALI) causes life-threatening clinical problem, and its underlying etiology includes inflammation and apoptosis. An adenosine A2A receptor agonist, polydeoxyribonucleotide (PDRN), exhibits anti-inflammatory and anti-apoptotic effects by inhibiting the secretion of pro-inflammatory cytokines. In the current study, the protective effect of PDRN against carbon tetrachloride (CCl4)-induced ALI was investigated using mice. For the induction of ALI, mice received intraperitoneal injection of CCl4 twice over seven days. Mice from the PDRN-treated groups received an intraperitoneal injection of 200 μL saline containing PDRN (8 mg/kg), once a day for seven days, starting on day 1 after the first CCl4 injection. In order to confirm that the action of PDRN occurs through the adenosine A2A receptor, 8 mg/kg 3,7-dimethyl-1-propargylxanthine (DMPX), an adenosine A2A receptor antagonist, was treated with PDRN. Administration of CCl4 impaired liver tissue and increased the liver index and histopathologic score. The expression of pro-inflammatory cytokines was increased, and apoptosis was induced by the administration of CCl4. Administration of CCl4 activated nuclear factor-kappa B (NF-κB) and facilitated phosphorylation of signaling factors in mitogen-activated protein kinase (MAPK). In contrast, PDRN treatment suppressed the secretion of pro-inflammatory cytokines and inhibited apoptosis. PDRN treatment inactivated NF-κB and suppressed phosphorylation of signaling factors in MAPK. As a result, liver index and histopathologic score were reduced by PDRN treatment. When PDRN was treated with DMPX, the anti-inflammatory and anti-apoptotic effect of PDRN disappeared. Therefore, PDRN can be used as an effective therapeutic agent for acute liver damage.

Irbesartan mitigates acute liver injury, oxidative stress, and apoptosis induced by acetaminophen in mice.

Hepatotoxicity induced by acetaminophen (APAP)-overdose is a major concern in clinical practice. In the present work, the detoxifying effect of irbesartan (Irb) on the APAP-induced acute liver injury was evaluated in mice. Induction of acute liver injury in mice was established by a single intraperitoneal (IP) injection of APAP (0.5 g/kg), then mice were injected with Irb (50 or 75 mg/kg, IP), each given twice at 1 and 12 hours post APAP injection. Liver functions, hepatic oxidative and nitrosative stress markers, and liver histopathology were determined after 24 hours. Hepatic cytochrome P450 2E1 (CYP2E1), nuclear factor-κB (NF-κB), tumor necrosis factor-α (TNF-α), caspase-3, B-cell lymphoma 2 (Bcl-2), and Bcl-2-associated X protein (Bax) levels were also estimated. Immunohistochemical evaluations of hepatic expression of phosphorylated NF-kB and active caspase-3 were assigned. Irb treatment attenuated APAP-induced acute liver injury. Irb suppressed APAP-caused elevation of liver enzymes as well as oxidative and nitrosative stress in liver tissues as evidenced by the decrease in hepatic CYP2E1 expression and hepatic levels of malondialdehyde and nitric oxide in addition to the elevated hepatic superoxide dismutase activity and reduced glutathione concentration. Also, Irb mitigated APAP-induced inflammation in liver tissues via decreasing the expression of hepatic NF-κB, phosphorylated NF-κB and TNF-α, and attenuated hepatic apoptosis via decreasing Bax/Bcl-2 ratio and caspase 3 expression and activation. Also, Irb mitigated the APAP-induced histopathological changes in liver specimens. These data suggested that Irb ameliorates APAP-induced acute liver injury through antioxidant, anti-inflammatory, and antiapoptotic activities.

Heatstroke-induced hepatocyte exosomes promote liver injury by activating the NOD-like receptor signaling pathway in mice.

BackgroundLiver injury is a common and important clinical issue of severe heat stress (HS), which has toxic effects and promotes subsequent multiple organ failure. The pathogenesis of HS-induced liver injury has not been fully elucidated. Passively injured hepatocytes also drive liver injury. Exosomes, extracellular vesicles secreted by hepatocytes as “danger signals,” mediate the intercellular transportation of diverse functional protein cargoes and modulate the biological processes of target cells. However, whether hepatocyte exosomes are involved in HS-induced liver injury has not been reported. The purpose of the current study was to clarify the release of hepatocyte exosomes under HS conditions and to explore their role in mediating HS-induced liver injury.MethodsHS was induced in hepatocytes or mice by hyperthermic treatment at 43.0 °C for 1 h. Exosomes from control and HS-exposed hepatocytes were isolated by standard differential ultracentrifugation. The hepatocyte exosomes were characterized, and the differentially expressed proteins of the control and HS exosomes were identified by isobaric tags for relative and absolute quantitation (iTRAQ) mass spectrometry and subjected to Kyoto encyclopedia of genes and genomes (KEGG) pathway analysis. Recipient hepatocytes were treated with control or HS exosomes, whereas in vivo, the exosomes were infused into mice. The internalization of HS hepatocyte exosomes by hepatocytes or the liver was tracked. The effect of HS exosomes on the activation of the NOD-like receptor signaling pathway and liver injury was demonstrated in vitro and in vivo.ResultsHS induced an increase in the release of exosomes from hepatocytes, which were internalized by recipient liver cells in vitro and taken up by the liver in vivo. HS significantly changed the proteomic profiles of hepatocyte exosomes based on the iTRAQ analysis. The KEGG pathway analysis revealed the enrichment of proteins associated with injury and inflammatory signaling pathways, especially the NOD-like receptor signaling pathway, the activity of which was upregulated. Subsequently, the capacity of HS hepatocyte exosomes to activate the NOD-like receptor signaling pathway was verified and found to aggrevate liver damage and inflammation in vitro and in vivo.ConclusionsThis study is the first preliminary study to demonstrate the induction of acute liver injury by hepatic exosomes in the setting of severe HS and reveals potentially related pathways. These results provide a basis for future research and the identification of new targets for clinical intervention.

Therapeutic applications of adipose-derived mesenchymal stem cells on acute liver injury in canines

In this study, canine adipose-derived mesenchymal stem cells (cADSCs) therapeutic potential was investigated in artificially induced acute liver injury model by CCl4 in canines. The primary cADSCs cells were cultured and then intravenously administered into the canine animal model. Six cross-breed dogs were divided into three groups including blank control group, CCl4 model group, CCl4 induced cADSCs transplantation group.The results showed that after intraperitoneal injection of CCl4 solution, the levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) and Albumin (ALB) in peripheral blood of experimental canines confirmed the correct induction of acute liver injury. Moreover, the liver structure showed clear macroscopic damage. The cADSCs were homed in the liver of the administered animals. The AST, ALT and ALB in the peripheral blood rapidly decreased. H&E and PAS histological evaluation showed that both the structure of canine liver tissue and the ability to synthesize hepatic glycogen could be restored to the control level after cADSCs transplantation. Therefore, cADSCs can play a therapeutic role in the recovery of liver injury. Overall, this study demonstrates that the primary cADSCs transplantation into the acute liver injury model induced by intravenous injection can play a certain therapeutic role in the recovery of liver in canines. These results may provide a new treatment idea for acute liver disease in pets clinically.

MiR-223 represents a biomarker in acute and chronic liver injury.

Dysregulation of miRNAs has been described in tissue and serum from patients with acute and chronic liver diseases. However, only little information on the role of miR-223 in the pathophysiology of acute liver failure (ALF) and liver cirrhosis is available. We analysed cell and tissue specific expression levels as well as serum concentrations of miR-223 in mouse models of acute (hepatic ischaemia and reperfusion, single CCl4 injection) and chronic (repetitive CCl4 injection, bile duct ligation (BDL)) liver diseases. Results were validated in patients and correlated with clinical data. The specific hepatic role of miR-223 was analysed by using miR-223-/- mice in these models. miR-223 expression was significantly dysregulated in livers from mice after induction of acute liver injury and liver fibrosis as well as in liver samples from patients with ALF or liver cirrhosis. In acute and chronic models, hepatic miR-223 up-regulation was restricted to hepatocytes and correlated with degree of liver injury and hepatic cell death. Moreover, elevated miR-223 expression was reflected by significantly higher serum levels of miR-223 during acute liver injury. However, functional in vitro and in vivo experiments revealed no differences in the degree of liver cell death and liver fibrosis as miR-223-/- mice behaved identical with wild-type (wt) mice in all tested models. miR-223 represents a promising diagnostic marker in a panel of serum markers of liver injury. Together with previously published data, our results highlight that the role of miR-223 in the pathophysiology of the liver is complex and needs further analysis.

Liuweiwuling tablets attenuate acetaminophen-induced acute liver injury and promote liver regeneration in mice.

To explore the mechanism of protection against acetaminophen-induced acute liver injury by Liuweiwuling tablets. Intraperitoneal injections of acetaminophen (250 mg/kg) were used to induce acute liver injury in male C57BL/6 mice. A total of 24 healthy mice were randomly assigned to two groups: an acute liver injury group (control group) and a Liuweiwuling tablet group. Mice were given Liuweiwuling tablets or a vehicle (PBS) orally prior to the administration of acetaminophen. Serum alanine aminotransferase (ALT) and aspartate aminotransaminase (AST) levels were measured at different time points within one week, and pathological examinations of liver tissues were performed 36 h after induction of acute liver injury. Serum inflammatory cytokines, such as high mobility group box protein B1 (HMGB1), tumor necrosis factor (TNF)-α and interleukin IL-1β, were detected using an ELISA method according to the manufacturer's instructions. Hepatic morphological changes at 36 h were assessed by hematoxylin and eosin staining. Expression of proliferating cell nuclear antigen (PCNA) in liver tissue was determined by Western blot analysis. The mRNA levels of hepatocyte proliferation markers (PCNA, CyclinD1 and p21) were detected by real-time quantitative reverse transcription-polymerase chain reaction. The levels of ALT/AST in the Liuweiwuling tablet group were decreased significantly at 6, 12 and 24 h compared to that of the control group (654.38 ± 120.87 vs 1566.17 ± 421.64, 1154.18 ± 477.72 vs 4654.84 ± 913.71 and 935.13 ± 252.34 vs 4553.75 ± 727.37, P < 0.01). Serum HMGB1 levels at 6 and 12 h for the Liuweiwuling tablet group were significantly lower than those of the control group (23.49 ± 3.89 vs 58.6 ± 3.65, 61.62 ± 13.07 vs 27.32 ± 5.97, P < 0.01). Furthermore, serum TNF-α and IL-1β levels at 12 h in the Liuweiwuling tablet group were also significantly lower than those of the control group (299.35 ± 50.61 vs 439.03 ± 63.59, 57.42 ± 12.98 vs 160.07 ± 49.87, P < 0.01). Centrilobular necrosis was evident in liver tissue of mice with acetaminophen-induced acute liver injury, but was almost abolished in the Liuweiwuling tablet group. The expression levels of PCNA and CyclinD1 were up-regulated in liver tissue in the Liuweiwuling tablet group (321.08 ± 32.87 vs 157.91 ± 21.52, 196.37 ± 25.39 vs 68.72 ± 11.27, P < 0.01); however, expression of p21 in liver tissue was down-regulated compared to that of the control group (40.26 ± 9.97 vs 138.24 ± 13.66, P < 0.01). Liuweiwuling tablets can attenuate acute liver injury by decreasing inflammatory cytokine (HMGB1, TNF-α and IL-1β) levels and promoting liver regeneration.

Cell-free DNA as a potential marker to predict carbon tetrachloride-induced acute liver injury in rats.

Finding an optimal biomarker for the noninvasive evaluation of acute liver injury (ALI) may be of great value in predicting clinical outcomes and investigating potential treatments. We investigated cell-free DNA (CFD) as a potential biomarker to predict carbon tetrachloride-induced ALI in rats. Forty-five Sprague-Dawley rats were randomly assigned to three groups. ALI was induced by carbon tetrachloride via a nasogastric tube at 1, 2.5, or 5ml/kg of a 50% solution. Fifteen additional rats underwent a sham procedure. Blood samples were drawn at time t which was 0 (baseline), 3, 6, 12, 24, 48, 72, 96, and 120h for the measurements of CFD, glutamate-pyruvate transaminase (GPT), glutamate-oxaloacetate transaminase (GOT), and total bilirubin. Prothrombin time and histology were examined at 24 and 120h following injection of 5ml/kg carbon tetrachloride in 18 additional rats and in 10 control rats. CFD levels in rats subjected to carbon tetrachloride-induced ALI were significantly increased in all blood samples starting at 12h after the induction of ALI (p<0.001), reaching peak levels at 24h. Blood GOT, GPT, and total bilirubin were elevated in all blood samples starting at 3h after the induction of ALI (p<0.0001), reaching peak levels by 48h. A positive correlation was demonstrated between CFD levels and GOT (R (2)=0.92), GPT (R (2)=0.92), and total bilirubin (R (2)=0.76). CFD levels correlated with liver damage seen on histological examination, as well as predicted liver damage, at 24h after ALI. CFD may be a useful biomarker for the prediction and measurement of ALI. There is no evidence to suggest that CFD is superior to other available noninvasive biomarkers.

Loss of Caspase-8 Protects Mice Against Inflammation-Related Hepatocarcinogenesis but Induces Non-Apoptotic Liver Injury

Disruption of the nuclear factor-κB (NF-κB) essential modulator (NEMO) in hepatocytes of mice (NEMO(Δhepa) mice) results in spontaneous liver apoptosis and chronic liver disease involving inflammation, steatosis, fibrosis, and development of hepatocellular carcinoma. Activation of caspase-8 (Casp8) initiates death receptor-mediated apoptosis. We investigated the pathogenic role of this protease in NEMO(Δhepa) mice or after induction of acute liver injury. We created mice with conditional deletion of Casp8 in hepatocytes (Casp8(Δhepa)) and Casp8(Δhepa)NEMO(Δhepa) double knockout mice. Acute liver injury was induced by Fas-activating antibodies, lipopolysaccharides, or concanavalin A. Spontaneous hepatocarcinogenesis was monitored by magnetic resonance imaging. Hepatocyte-specific deletion of Casp8 protected mice from induction of apoptosis and liver injury by Fas or lipopolysaccharides but increased necrotic damage and reduced survival times of mice given concanavalin A. Casp8(Δhepa)NEMO(Δhepa) mice were protected against steatosis and hepatocarcinogenesis but had a separate, spontaneous phenotype that included massive liver necrosis, cholestasis, and biliary lesions. The common mechanism by which inactivation of Casp8 induces liver necrosis in both injury models involves the formation of protein complexes that included the adaptor protein Fas-associated protein with death domain and the kinases receptor-interacting protein (RIP) 1 and RIP3-these have been shown to be required for programmed necrosis. We demonstrated that hepatic RIP1 was proteolytically cleaved by Casp8, whereas Casp8 inhibition resulted in accumulation of RIP complexes and subsequent liver necrosis. Inhibition of Casp8 protects mice from hepatocarcinogenesis following chronic liver injury mediated by apoptosis of hepatocytes but can activate RIP-mediated necrosis in an inflammatory environment.

Role of age and uncoupling protein-2 in oxidative stress, RAGE/AGE interaction and inflammatory liver injury

The objective of this study is to clarify whether age-related oxidative stress enhances hepatic vulnerability via increased interaction of advanced glycation endproducts (AGE) with their receptor RAGE. To further address the role of uncoupling of mitochondrial respiration, mitochondrial uncoupling protein-2 wild-type (UCP2+/+) and knock out (UCP2−/−) mice were used and studied at an age of 8 (young), 38 (adult) and 76 weeks (senescent). First, we could show that UCP2 protein expression increased with age in UCP2+/+ mice. Second, in both mouse strains oxidative stress, as measured by malondialdehyde concentrations and the ratio of glutathione to glutathione disulfide, as well as hepatic RAGE expression and highly modified AGE accumulation significantly increased with age. This, however, was far more pronounced in UCP2−/− mice, in particular at the young age of 8 wk. In addition, the hepatic activity of the AGE precursor detoxifying enzyme glyoxalase-I was significantly decreased in 8 wk old UCP2−/− animals and concomitantly caused 2-fold higher levels of methylglyoxal-modified AGE in these animals. We further showed that the numbers of hepatic cells expressing sRAGE which acts as a decoy for RAGE ligands decreased with age and were markedly lower in the UCP2−/− than the UCP2+/+ mice. As a consequence, young 8 wk old UCP2−/− mice benefited from treatment with recombinant mouse RAGE to block the RAGE/AGE interaction, when challenged with galactosamine/lipopolysaccharide for the induction of acute liver injury. They showed less pronounced tissue damage and slightly lower mortality rate, while older UCP2+/+ and UCP2−/− mice revealed comparably high mortality rates and extent of liver injury, irrespective of their treatment with rRAGE. Taken together, the present study underlines the role of UCP2 in the age-related increase of oxidative stress and the oxidative stress-related RAGE/AGE interaction. In young animals, blockade of the RAGE/AGE interaction is of benefit, while in older animals, this protective effect is lost, supposedly due to the fact that with age other factors than enhanced hepatic glycation products predominantly determine liver injury and injury-related mortality rate.