Acetaminophen-induced hepatotoxicity

Phylogenetic origins for severe acetaminophen toxicity in snake species compared to other vertebrate taxa

While it has been known for a while that some snake species are extremely sensitive to acetaminophen, the underlying mechanism for this toxicity has not been reported. To investigate if essential detoxification enzymes are missing in snake species that are responsible for biotransformation of acetaminophen in other vertebrate species, livers were collected from a variety of snake species, together with samples from alligator, snapping turtle, cat, rat, and cattle. Subcellular fractions were analyzed for enzymatic activities of phenol-type sulfotransferase and UDP‑glucuronosyltransferase, total glutathione S‑transferase, and N‑acetyltransferase. The results showed that none of the snake species, together with the cat samples, had any phenol-type glucuronidation activity, and that this activity was much lower in alligator and turtle samples than in the mammalian species. Combined with the lack of N‑acetyltransferase activity in snakes and cats, this would explain the accumulation of the aminophenol metabolite, which induces methemoglobinemia and subsequent suffocation of snakes and cats after acetaminophen exposure. While previous investigations have concluded that in cats the gene for the phenol-type glucuronosyltransferase isoform has turned into a pseudogene because of several point mutations, evaluation of genomic information for snake species revealed that they have only 2 genes that may code for glucuronosyltransferase isoforms. Similarity of these genes with mammalian genes is <50%, and suggests that the expressed enzymes may act on other types of substrates than aromatic amines. This indicates that the extreme sensitivity for acetaminophen in snakes is based on a different phylogenetic origin than the sensitivity observed in cats.

Inhibition of cytochrome P450 3A protein degradation and subsequent increase in enzymatic activity through p38 MAPK activation by acetaminophen and salicylate derivatives

Cytochrome P450 (CYP) 3A4 plays an important role in drug metabolism. Although transcriptional regulation of CYP3A expression by chemicals has been comprehensively studied, its post-translational regulation is not fully understood. We previously reported that acetaminophen (APAP) caused accumulation of functional CYP3A protein via inhibition of CYP3A protein degradation through reduction of glycoprotein 78 (gp78), an E3 ligase of the ubiquitin proteasome system. Furthermore, N-acetyl-m-aminophenol, a regioisomer of APAP causes CYP3A protein accumulation, whereas p-acetamidobezoic acid, in which a hydroxy group of APAP was substituted for a carboxy group, did not lead to the same effects. However, the mechanism underlying the reduction of gp78 protein expression by APAP has not yet been elucidated. In this study, we selected 32 compounds including a phenolic hydroxyl group such as APAP and explored the compounds that increased CYP3A enzyme activity to analyze their common mechanism. Four compounds, including salicylate, increased CYP3A enzyme activity and led to the accumulation of functional CYP3A protein similarly to APAP. APAP and salicylate activate p38 mitogen-activated protein kinase (p38 MAPK). gp78 is known to be phosphorylated by p38 MAPK; so, we investigated the relationship between p38 MAPK and CYP3A. APAP activated p38 MAPK, decreased gp78 protein expression, and subsequently induced CYP3A protein expression in a time-dependent manner. When SB203580, a p38 MAPK inhibitor, was co-administered with APAP, the inhibitory effects of APAP on CYP3A protein degradation were suppressed. In this study, we demonstrated the involvement of the p38 MAPK-gp78 pathway in suppressing CYP3A protein degradation by APAP. Salicylate derivatives may also suppress the CYP3A protein degradation.

Animal Prescriptions in a Human World – Handling Veterinary Prescriptions in the Community-Practice Setting

Veterinary prescriptions are becoming more common in the community-practice setting due to a variety of factors, including cost, availability, convenience and legislation changes. However, veterinary patients are not simply small humans with regards to drug use, and this can be seen in dosages that drastically differ from those used in humans, beyond adjustment for size differences. Therefore, it is important for a pharmacist filling these prescriptions to have an understanding of basic differences regarding drug disposition in veterinary patients as well as factors that may influence toxicity and/or adverse effects. This article also reviews commonly used veterinary drug references that a pharmacist can use in the community-practice setting to aid in review of veterinary prescriptions.

High-Throughput Assessment of Mechanistic Toxicity of Chemicals in Miniaturized 3D Cell Culture

High-content imaging (HCI) assays on two-dimensional (2D) cell cultures often do not represent in vivo characteristics accurately, thus reducing the predictability of drug toxicity/efficacy in vivo. On the other hand, conventional 3D cell cultures are relatively low throughput and possess difficulty in cell imaging. To address these limitations, a miniaturized 3D cell culture has been developed on a micropillar/microwell chip platform with human cells encapsulated in biomimetic hydrogels. Model compounds are used to validate human cell microarrays for high-throughput assessment of mechanistic toxicity. Main mechanisms of toxicity of compounds can be investigated by analyzing multiple parameters such as DNA damage, mitochondrial impairment, intracellular glutathione level, and cell membrane integrity. IC₅₀ values of these parameters can be determined and compared for the compounds to investigate the main mechanism of toxicity. This paper describes miniaturized HCI assays on 3D-cultured cell microarrays for high-throughput assessment of mechanistic profiles of compound-induced toxicity. © 2018 by John Wiley & Sons, Inc.

Histopathological study of liver tissue due to methadone consumption and its effect on liver enzymes and inflammatory indices in rat

Background

Methadone (MET)-based treatment is currently one of the best known approaches in the treatment of opioid dependence. It is claimed that MET use exerts adverse effects on the performance of some organs, especially liver. Thus, the present study aims to investigate MET effects on the hepatic tissue as well as its effect on the hepatic enzyme levels and inflammatory markers in rats.

Materials and methods

Twenty-eight mature male Wistar rats underwent an 8-week treatment in four equal groups including the control group (an ordinary daily dietary regime) as well as the experimental groups 1, 2, and 3 (an ordinary daily dietary regime and gavage-fed on MET syrup for 5, 20, and 40 mg/kg body weight per day). Blood samples were collected from all rats in the beginning and end of the study to measure their hepatic enzyme levels and inflammatory markers. In the end, their livers were subjected to histological examinations.

Results

The mean serum levels of hepatic enzymes (alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase) increased considerably across all the three groups that had received various dosages of MET (5, 20, and 40 mg/kg) in the end of the study as compared to the beginning of the study (P<0.001). It was also found that the inflammatory indicators (interleukin-6, tumor necrosis factor-alpha, and C-reactive protein) rose significantly in the groups that had received various dosages of MET in contrast to the control group (P<0.01, P<0.001, and P<0.001, respectively). The histopathological images of the liver cross-sections revealed dosage-dependent tissue changes in the groups that had received various dosages of MET.

Conclusion

The present study tried to prove the adverse effects of MET in the development of liver damage. Since MET-based treatment is frequently prescribed by physicians for curing the addiction to narcotics, better strategies are required for its correct usage.

Targeted cellular delivery of robust enzyme nanoparticles for the treatment of drug-induced hepatotoxicity and liver injury

Direct delivery of proteins into cells has been considered an effective approach for treating the protein-related diseases. However, clinical use of proteins has still been limited due to their instability in the blood and poor membrane permeability. To achieve an efficient cellular delivery of the protein to target cells via a systemic administration, a multifunctional carrier system having desirable stability both in the blood stream and the cells, specific cell-targeting property and endosomal escape functions may be required. In this study, we prepared a catalytic nanoparticle containing an active enzyme by cross-tethering multiple superoxide dismutase (SOD) molecules with catechol-derivatized hyaluronic acid (HA). The permeable shell of hydrophilic HA chains effectively protects the enzyme from degradation in the blood after intravenous administration and provides an additional function for targeting hepatocytes expressing HA receptor (CD44). The structure and catalytic activity of the enzyme molecules in the nanoparticle were not significantly compromised in the nanoparticle. In addition, ultra-small calcium phosphate nanoparticles (USCaP, 2-5 nm) were crystalized and decorated on the surface of the nanoparticle for the efficient endosomal escape after cellular uptake. The SOD-containing nanoparticle fortified with USCaP was used for the treatment of acetaminophen (APAP)-induced fulminant hepatotoxicity and liver injury. The nanoparticle achieved the efficient hepatic cellular delivery of SOD via a systemic administration and resulted in efficient removal of reactive oxygen species (ROS) in the liver and remarkable improvement of APAP-induced hepatotoxicity and liver injury in animals. STATEMENT OF SIGNIFICANCE: Despite the enormous therapeutic potential, the intracellular delivery of proteins has been limited due to their poor membrane permeability and stability. In this study, we demonstrated an active enzyme-containing nanoparticle functionalized by hyaluronic acid and ultra-small size calcium phosphate nanoparticles (2-5 nm) for targeted cellular delivery of superoxide dismutase (SOD). The nanoparticle was designed to integrate all the essential functions, including serum stability, target specificity, and endosomal escape capability, for a systemic delivery of a therapeutic protein to the cells of the liver tissue. The intravenous administration of the nanoparticle efficiently removes reactive oxygen species (ROS) in the liver and remarkably improves the drug-induced hepatotoxicity and the progress of fulminant liver injury in an acetaminophen-overdose animal model.

Chemical induction of hepatic apoptosis in rodents

The urge of identifying new pharmacological interventions to prevent or attenuate liver injury is of critical importance and needs an expanded experimental toolbox. Hepatocyte injury and cellular death is a prominent feature behind the pathology of liver diseases. Several research activities focused on identifying chemicals and hepatotoxicants that induce cell death by apoptosis, in addition to presenting its corresponding signaling pathway. Although such efforts provided further understanding of the mechanisms of cell death, it has also raised confusion concerning identifying the involvement of several modes of cell death including apoptosis, necrosis and fibrosis. The current review highlights the ability of several chemicals and potential hepatotoxicants to induce liver damage in rodents by means of apoptosis while the probable involvement of other modes of cell death is also exposed. Thus, several chemical substances including hepatotoxins, mycotoxins, hyperglycemia inducers, metallic nanoparticles and immunosuppressant drugs are reviewed to explore the hepatic cytotoxic spectrum they could exert on hepatocytes of rodents. In addition, the current review address the mechanism by which hepatotoxicity is initiated in hepatocytes in different rodents aiding the researcher in choosing the right animal model for a better research outcome.

A spatial-temporal model for zonal hepatotoxicity of acetaminophen

The metabolism zonation in liver lobules is well known yet its incorporation into the mathematical models of acetaminophen (APAP) metabolism is still primitive - only the oxidation pathway via reaction with the cytochrome P450 (CYP450) has been considered, yet the zonal heterogeneity exhibits in all three pathways including sulphation, glucuronidation and oxidation. In this paper we present a novel computational method where an intracellular APAP metabolism model is integrated into a Finite Element Model (FEM) of sinusoids, and the zonal heterogeneity in three metabolism pathways are all incorporated. We demonstrate that the degradation of APAP, detoxification via glutathione (GSH) and the formation of hepatotoxicity, are all affected profoundly by the zonal difference. Specifically, glucuronidation plays a major role in the degradation of APAP. Generation of GSH, its conjugation with the toxic NAPQI and the spatial distribution of CYP450 combined together determine the toxicity of APAP. We suggest that the current platform be used for further hepatotoxicity study of APAP by incorporating other heterogeneity factors.

CYP3A Activation and Glutathione Depletion Aggravate Emodin-Induced Liver Injury

1,3,8-Trihydroxy-6-methylanthraquinone (emodin), a widely existing natural product in herbal medicines, has been reported to be hepatotoxic, but the exact underlying mechanism is still not fully understood. The objective of the present study was to evaluate the role of CYP3A and glutathione (GSH) in emodin-induced liver injury. Primary human hepatocytes were exposed to emodin with and without addition of CYP3A inducer/inhibitor and GSH synthesis inhibitor. It was found that emodin-mediated cytotoxicity increased when CYP3A was activated and GSH was depleted. Hepatotoxicity induced by emodin in rats by activation/inhibition of CYP3A and depletion of GSH was further investigated. Administration of emodin in combination with l-buthionine sulfoximine (BSO) or dexamethasone (DEX) resulted in aggravated liver injury, whereas pretreatment with ketoconazole (KTZ) suppressed the side effects caused by emodin. In addition, plasma exposure of emodin and its glucuronide metabolite were measured by ultraperformance liquid chromatography triple quadrupole mass spectrometry. Emodin and its glucuronide were lower in BSO-, DEX-, and KTZ- co-treated rats compared with those administered with emodin alone. In conclusion, these mentioned results suggested that CYP3A induction and GSH depletion might be involved in hepatotoxicity induced by emodin. This study may help to understand the risk factors and the mechanism of hepatotoxicity of emodin in humans.

Mass isotopomer-guided decluttering of metabolomic data to visualize endogenous biomarkers of drug toxicity

Metabolomics offers the opportunity to uncover endogenous biomarkers that can lead to metabolic pathways and networks and that underpin drug toxicity mechanisms. A novel protocol is presented and discussed that is applicable to drugs which generate urinary metabolites when administered to mice sensitive to its toxicity. The protocol would not apply to drugs that are not metabolized or eliminated by a different route. Separate stable isotope-labeled and unlabeled drug administration to mice is made together with collection of urines from control animals. Untargeted mass spectrometry-based metabolomic analysis of these three urine groups is conducted in addition to principal components analysis (PCA). In the case of unlabeled acetaminophen and [acetyl-²H₃]acetaminophen, each given at a hepatotoxic dose (400 mg/kg i.p.) to the sensitive mouse strain (wild-type 129), the PCA loadings plot showed a distribution of ions in the shape of a "fallen-Y" with the deuterated metabolites in one arm and the paired nondeuterated metabolites in the other arm of the fallen-Y. Ions corresponding to the endogenous toxicity biomarkers sat in the mouth of the fallen-Y. This protocol represents an innovative means to separate endogenous biomarkers from drug metabolites, thereby aiding the identification of biomarkers of drug toxicity. For acetaminophen, increased hepatic oxidative stress, mitochondrial damage, Ca²⁺ signaling, heme catabolism, and saturation of glucuronidation, together with decreased fatty acid β-oxidation and cellular energy dysregulation were all implied from the discovered biomarkers. The protocol can be applied to other drugs and may now be translated to clinical studies.

Platycodin D protects acetaminophen-induced hepatotoxicity by inhibiting hepatocyte MAPK pathway and apoptosis in C57BL/6J mice

The root of Platycodon grandiflorus (Jacq.) A. DC. (P. grandiflorus), Platycodonis Radix, has been commonly applied to prevent and treat human diseases including bronchitis, asthma and excessive phlegm. Platycodin D (PD), one of the most important therapeutic components of P. grandiflorus, has been reported to possess protective effect against alcohol and carbon tetrachloride induced hepatotoxicity. In this study, we examined the protective efficacy of PD on acetaminophen (APAP)-induced liver injury and possible underlying mechanisms in C57BL/6J mice. Administration of PD prior to APAP intoxication significantly ameliorated the increase in serum transferases, interleukin 1β (IL-1β), IL-6, tumor necrosis factor alpha (TNF-α), and hepatic malondialdehyde (MDA) and the depletion of glutathione (GSH) in mice. PD pretreatment decreased the expression of heme oxygenase-1 (HO-1), cyclooxygenase-2 (COX-2) and nuclear factor kappa B (NF-κB) in presence of APAP. Moreover, PD treatment noticeably reduced APAP-induced hepatocyte necrosis and apoptosis evidenced by evaluating physiological and histological hepatocyte changes in mice. Finally, PD pretreatment significantly diminished c-Jun NH₂-terminal kinase (JNK), extracellular signal-regulated kinases 1 and 2 (ERK1/2), and p38 phosphorylation induced by APAP. Collectively, PD pretreatment effectively protects hepatocytes against APAP-induced hepatotoxicity in mice through ameliorating oxidative stress, inflammatory response, and hepatocyte apoptosis.

A new bioluminescent imaging technology for studying oxidative stress in the testis and its impacts on fertility

PURPOSE

Excessive oxidative stress (OS) leads to cellular dysfunctions and cell death and constitutes a major cause of male infertility. However, the etiologies of increased reactive oxygen species (ROS) in male infertility is not fully understood. One major limitation is the lack of an in vivo imaging system that can be used to effectively study the impact of excessive ROS in the testis. Recently, we discovered that the hepatocellular carcinoma reporter (HCR) mice previously generated in our laboratory also expressed luciferase in the spermatids of the testis. The goal of the current study is to use the HCR mice to detect OS in the testis and to investigate the potential use of this new system in studying OS-induced male infertility.

EXPERIMENTAL DESIGN

Bioluminescence imaging (BLI) was performed in HCR mice that were treated with peroxy caged luciferin-1 (PCL-1), an OS reporter, to establish a new mouse model for in vivo monitoring of the OS status inside the male reproductive tract. Subsequently, the effect of acetaminophen (APAP) overdose on the OS inside the testis and male fertility were determined. Lastly, APAP was co-administered with glutathione, an antioxidant reagent, to test if the HCR mice can serve as a model for the effective and rapid assessment of the potency of individual agents in modifying the OS inside the mouse testis.

RESULTS

The OS level in the testis in the HCR mice was readily detected by BLI. The use of this new model led to the discovery that APAP caused a sudden rise of OS in the testis and was a potent toxicant for the male reproductive system. Moreover, administration of glutathione was effective in preventing the APAP-induced elevation of OS and in ameliorating all of the OS-induced anomalies in the testis.

CONCLUSIONS

The HCR mice represent an excellent model for monitoring OS change in the mouse testis by real time BLI. APAP is a potent male reproductive toxicant and APAP-treated mice represent a valid model for OS-induced male infertility. This model can be used to study OS-induced damage in male reproductive tract and in assessing the effects of therapeutic agents on the relative levels of OS and male fertility.

The effects of colostrum on some biochemical parameters in the experimental intoxication of rats with paracetamol

In the current study, the possible prophylactic and therapeutic effects of colostrum (COL) on acute organ injury caused by paracetamol (PAR) in rats were evaluated. Within the scope of this study, a 2-month-old male (150-200 g) 70 Wistar Albino rat was used and a total of seven groups were designed. The first group (CNT) was maintained for control purposes. The second group (COL-1) was given COL for 1 day, at a dose of 500 mg/kg at 6-h intervals, and blood and tissue sampling was performed at 24 h. The third group (COL-7) received COL for 7 days, at a dose of 500 mg/kg at 6-h intervals on day 1 and at a daily dose of 500 mg/kg on the following days, and blood and tissue samples were taken at the end of seventh day. The fourth group (PAR-1) was administered with PAR at a dose of 1.0 g/kg bw and was blood and tissue sampled at 24 h. The fifth group (PAR-7) received PAR at a dose of 1.0 g/kg bw on day 1 and was blood and tissue was removed at the end of day 7. The sixth group (PAR+COL-1) was administered with a combination of PAR (1 g/kg bw) and COL (500 mg/kg at 6-h intervals), and blood and tissue samples were collected at 24 h. The seventh group (PAR+COL-7) received 1.0 g/kg bw of PAR on day 1 and was given COL throughout the 7-day study period (at a dose of 500 mg/kg at 6-h intervals on day 1 and at a daily dose of 500 mg/kg on the following days). In the seventh group, blood and tissue samples were taken at the end of seventh day. Alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), blood urea nitrogen (BUN), glucose, creatinine, triglyceride, total bilirubin, total protein and albumin levels/activities were analysed in the serum samples. The malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) levels/activities, known as oxidative stress parameters, were assayed for tissue homogenates and blood (erythrocytes/plasma); in addition, enzyme activities of GSH S-transferase (GST), cytochrome P4502E1 (CYP2E1), NADH-cytochrome b5 reductase (CYTB5), glucose-6-phosphate dehydrogenase (G6PD), NADPH-cytochrome P450 C reductase (CYTC) and glutathione (GSH) levels/activities defined as drug metabolising parameters were measured in liver homogenates. In result, it was determined that PAR caused significant alterations in some biochemical and lipid peroxidation parameters and the activities/levels of drug metabolising parameters in the liver and that COL normalised some of these parameters and reduced PAR-induced tissue damage.

Liver Immune Cells Release Type 1 Interferon Due to DNA Sensing and Amplify Liver Injury from Acetaminophen Overdose

Hepatocytes may rupture after a drug overdose, and their intracellular contents act as damage-associated molecular patterns (DAMPs) that lead to additional leukocyte infiltration, amplifying the original injury. Necrosis-derived DNA can be recognized as a DAMP, activating liver non-parenchymal cells (NPCs). We hypothesized that NPCs react to DNA by releasing interferon (IFN)-1, which amplifies acetaminophen (APAP)-triggered liver necrosis. We orally overdosed different knockout mouse strains to investigate the pathways involved in DNA-mediated amplification of APAP-induced necrosis. Mice were imaged under intravital confocal microscopy to estimate injury progression, and hepatocytes and liver NPCs were differentially isolated for gene expression assays. Flow cytometry (FACS) using a fluorescent reporter mouse estimated the interferon-beta production by liver leukocytes under different injury conditions. We also treated mice with DNase to investigate the role of necrosis DNA signaling in IFN-1 production. Hepatocytes released a large amount of DNA after APAP overdose, which was not primarily sensed by these cells. However, liver NPCs promptly sensed such environmental disturbances and activated several DNA sensing pathways. Liver NPCs synthesized and released IFN-1, which was associated with concomitant hepatocyte necrosis. Ablation of IFN-1 recognition in interferon α/β receptor (IFNAR^−/−) mice delayed APAP-mediated liver necrosis and dampened IFN-1 sensing pathways. We demonstrated a novel loop involving DNA recognition by hepatic NPCs and additional IFN-1 mediated hepatocyte death.

Hepatoprotective Effect of Polysaccharides Isolated from Dendrobium officinale against Acetaminophen-Induced Liver Injury in Mice via Regulation of the Nrf2-Keap1 Signaling Pathway

The effect of polysaccharides isolated from Dendrobium officinale (DOP) on acetaminophen- (APAP-) induced hepatotoxicity and the underlying mechanisms involved are investigated. Male Institute of Cancer Research (ICR) mice were randomly assigned to six groups: (1) control, (2) vehicle (APAP, 230 mg/kg), (3) N-acetylcysteine (100 mg/kg), (4) 50 mg/kg DOP, (5) 100 mg/kg DOP, and (6) 200 mg/kg DOP. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels in the serum and glutathione (GSH), malondialdehyde (MDA), catalase (CAT), total antioxidant capacity (T-AOC), myeloperoxidase (MPO), and reactive oxygen species (ROS) levels in the liver were determined after the death of the mice. The histological examination of the liver was also performed. The effect of DOP on the Kelch-like ECH-associated protein 1- (Keap1-) nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway was evaluated using Western blot analysis and real-time polymerase chain reaction (PCR). The results showed that DOP treatment significantly alleviated the hepatic injury. The decrease in ALT and AST levels in the serum and ROS, MDA, and MPO contents in the liver, as well as the increases in GSH, CAT, and T-AOC in the liver, were observed after DOP treatment. DOP treatment significantly induced the dissociation of Nrf2 from the Nrf2-Keap1 complex and promoted the Nrf2 nuclear translocation. Subsequently, DOP-mediated Nrf2 activation triggered the transcription and expressions of the glutamate-cysteine ligase catalytic (GCLC) subunit, glutamate-cysteine ligase regulatory subunit (GCLM), heme oxygenase-1 (HO-1), and NAD(P)H dehydrogenase quinone 1 (NQO1) in APAP-treated mice. The present study revealed that DOP treatment exerted potentially hepatoprotective effects against APAP-induced liver injury. Further investigation about mechanisms indicated that DOP exerted the hepatoprotective effect by suppressing the oxidative stress and activating the Nrf2-Keap1 signaling pathway.

Ginsenoside Rg1 protects against acetaminophen-induced liver injury via activating Nrf2 signaling pathway in vivo and in vitro

Acetaminophen (APAP) is a worldwide used drug for treating fever and pain. However, APAP overdose is the leading cause of drug-induced liver injury. The purpose of the current study is to evaluate the hepatoprotective effect of ginsenoside Rg1 (Rg1), the main pharmacologically active compounds of Panax ginseng, against APAP-induced acute liver injury, and further to elucidate the involvement of Nrf2 signaling pathway by in vivo and in vitro experiments. Male C57BL/6 mice were treated with Rg1 for 3 days before injection of APAP. Serum and liver tissue samples were collected 6 h later. The results indicated that Rg1 significantly attenuated APAP-induced hepatotoxicity and oxidative stress in a dose-dependent manner. Rg1 effectively enhanced antioxidant and detoxification capacity, which is largely dependent on up-regulating Nrf2 nuclear translocation, reducing Keap1 protein expression and up-regulating Nrf2 target genes including GCLC, GCLM, HO-1, NQO1, Ugt1a1, Ugt1a6, Ugt2b1, Sult2a1, Mrp2, Mrp3 and Mrp4. Furthermore, Rg1 repressed the activities of Cyp2e1, Cyp3a11, Cyp1a2, which are important enzymes in the formation of APAP toxic metabolite N-acetyl-p-benzoquinone imine. However, the changes in transporters and enzymes, as well as ameliorative liver histology induced by Rg1 were abrogated by Nrf2 antagonist all-transretinoic acid in vivo and Nrf2 siRNA in vitro. In conclusion, Rg1 produced hepatoprotective effects against APAP-induced acute liver injury via Nrf2 signaling pathway. Rg1 might be an effective approach for the prevention against acute liver injury.

Acetaminophen reduces the protein levels of high affinity amino acid permeases and causes tryptophan depletion

In yeast, toxicity of acetaminophen (APAP), a frequently used analgesic and antipyretic drug, depends on ubiquitin-controlled processes. Previously, we showed a remarkable overlap in toxicity profiles between APAP and tyrosine, and a similarity with drugs like rapamycin and quinine, which induce degradation of the amino acid permease Tat2. Therefore, we investigated in yeast whether APAP reduced the expression levels of amino acid permeases. The protein levels of Tat2, Tat1, Mup1 and Hip1 were reduced, while the expression of the general permease Gap1 was increased, consistent with a nutrient starvation response. Overexpression of Tat1 and Tat2, but not Mup1, Hip1 and Gap1 conferred resistance to APAP. A tryptophan auxotrophic strain trp1Δ was more sensitive to APAP than wild-type and addition of tryptophan completely restored the growth restriction of trp1∆ upon APAP exposure, while tyrosine had an additive effect on APAP toxicity. Furthermore, intracellular aromatic amino acid concentrations were reduced upon APAP exposure. This effect was less prominent in ubiquitin-deficient yeast strains that were APAP resistant and showed a reduced degradation of high affinity amino acid permeases. APAP-induced changes in intracellular amino acid concentrations were also detected in hepatoma HepG2 cells indicating significance for humans.

Hepatocyte SHP deficiency protects mice from acetaminophen-evoked liver injury in a JNK-signaling regulation and GADD45β-dependent manner

Acetaminophen (APAP) overdose is a leading cause of drug-induced acute liver failure. Prolonged c-Jun N-terminal kinase (JNK) activation plays a central role in APAP-induced liver injury; however, growth arrest and DNA damage-inducible 45 beta (GADD45β) is known to inhibit JNK phosphorylation. The orphan nuclear receptor small heterodimer partner (SHP, NR0B2) acts as a transcriptional co-repressor of various genes. The aim of the present study was to investigate the role of SHP in APAP-evoked hepatotoxicity. We used lethal (750 mg/kg) or sublethal (300 mg/kg) doses of APAP-treated wild-type (WT), Shp knockout (Shp^-/-), hepatocyte-specific Shp knockout (Shp^hep-/-), and Shp and Gadd45β double knockout (Shp^-/-Gadd45β^-/-) mice for in vivo studies. Primary mouse hepatocytes were used for a comparative in vitro study. SHP deficiency protected against APAP toxicity with an increased survival rate, decreased liver damage, and inhibition of prolonged hepatic JNK phosphorylation in mice, which was independent of APAP metabolism regulation. Furthermore, Shp^hep-/- mice showed diminished APAP hepatotoxicity compared with WT mice. SHP-deficient primary mouse hepatocytes also showed decreased cell death and inhibition of sustained JNK phosphorylation following toxic APAP treatment. While SHP expression declined, GADD45β expression increased after APAP treatment in WT mice. In Shp^-/- mice, APAP-evoked GADD45β induction was significantly enhanced. Notably, the ameliorative effects of SHP deficiency on APAP-induced liver injury were abolished in Shp^-/-Gadd45β^-/- mice. The current study is the first to demonstrate that hepatocyte-specific SHP deficiency protects against APAP overdose-evoked hepatotoxicity in a JNK signaling regulation and GADD45β dependent manner. SHP is suggested to be a novel therapeutic target for APAP overdose treatment.

Coconut water vinegar ameliorates recovery of acetaminophen induced liver damage in mice

Background

Coconut water has been commonly consumed as a beverage for its multiple health benefits while vinegar has been used as common seasoning and a traditional Chinese medicine. The present study investigates the potential of coconut water vinegar in promoting recovery on acetaminophen induced liver damage.

Methods

Mice were injected with 250 mg/kg body weight acetaminophen for 7 days and were treated with distilled water (untreated), Silybin (positive control) and coconut water vinegar (0.08 mL/kg and 2 mL/kg body weight). Level of oxidation stress and inflammation among treated and untreated mice were compared.

Results

Untreated mice oral administrated with acetaminophen were observed with elevation of serum liver profiles, liver histological changes, high level of cytochrome P450 2E1, reduced level of liver antioxidant and increased level of inflammatory related markers indicating liver damage. On the other hand, acetaminophen challenged mice treated with 14 days of coconut water vinegar were recorded with reduction of serum liver profiles, improved liver histology, restored liver antioxidant, reduction of liver inflammation and decreased level of liver cytochrome P450 2E1 in dosage dependent level.

Conclusion

Coconut water vinegar has helped to attenuate acetaminophen-induced liver damage by restoring antioxidant activity and suppression of inflammation.

Liver-specific deficiency of unc-51 like kinase 1 and 2 protects mice from acetaminophen-induced liver injury

unc-51-like autophagy activating kinase 1 and 2 (Ulk1/2) regulate autophagy initiation under various stress conditions. However, the physiological functions of these Ser/Thr kinases are not well characterized. Here, we show that mice with liver-specific double knockout (LDKO) of Ulk1 and Ulk2 (Ulk1/2 LDKO) are viable, but exhibit overt hepatomegaly phenotype. Surprisingly, Ulk1/2 LDKO mice display normal autophagic activity in hepatocytes upon overnight fasting, but are strongly resistant to acetaminophen (APAP)-induced liver injury. Further studies revealed that Ulk1/2 are also dispensable for APAP-induced autophagy process, but are essential for the maximum activation of c-Jun N-terminal kinase (JNK) signaling both in vivo and in isolated primary hepatocytes during APAP treatment. Mechanistically, APAP-induced inhibition of mechanistic target of rapamycin complex 1 releases Ulk1 from an inactive state. Activated Ulk1 then directly phosphorylates and increases the kinase activity of mitogen-activated protein kinase kinase 4 and 7 (MKK4/7), the upstream kinases and activator of JNK, and mediates APAP-induced liver injury. Ulk1-dependent phosphorylation of MKK7 was further confirmed by a context-dependent phosphorylation antibody. Moreover, activation of JNK and APAP-induced cell death was markedly attenuated in Mkk4/7 double knockdown hepatocytes reconstituted with an Ulk1-unphosphorylatable mutant of MKK7 compared to those in cells rescued with wild-type MKK7.

CONCLUSION

Together, these findings reveal an important role of Ulk1/2 for APAP-induced JNK activation and liver injury, and understanding of this regulatory mechanism may offer us new strategies for prevention and treatment of human APAP hepatotoxicity. (Hepatology 2018;67:2397-2413).

Cuscuta arvensis Beyr "Dodder": In Vivo Hepatoprotective Effects Against Acetaminophen-Induced Hepatotoxicity in Rats

Cuscuta arvensis Beyr. is a parasitic plant, and commonly known as "dodder" in Europe, in the United States, and "tu si zi shu" in China. It is one of the preferred spices used in sweet and savory dishes. Also, it is used as a folk medicine for the treatment particularly of liver problems, knee pains, and physiological hepatitis, which occur notably in newborns and their mothers in the southeastern part of Turkey. The purpose of this study was to investigate the hepatoprotective effects and antioxidant activities of aqueous and methanolic extracts of C. arvensis Beyr. on acetaminophen (APAP)-induced acute hepatotoxicity in rats. The results were supported by subsequent histopathological studies. The hepatoprotective activity of both the aqueous and methanolic extracts at an oral dose of 125 and 250 mg/kg was investigated by observing the reduction levels or the activity of alkaline phosphatase, alkaline transaminase, aspartate aminotransferase, blood urine nitrogen, and total bilirubin content. In vivo antioxidant activity was determined by analyzing the serum superoxide dismutase, malondialdehyde, glutathione, and catalase levels. Chromatographic methods were used to isolate biologically active compounds from the extract, and spectroscopic methods were used for structure elucidation. Both the methanolic and aqueous extracts exerted noticable hepatoprotective and antioxidant effects supporting the folkloric usage of dodder. One of the bioactive compounds was kaempferol-3-O-rhamnoside, isolated and identified from the methanolic extract.

p53 attenuates acetaminophen-induced hepatotoxicity by regulating drug-metabolizing enzymes and transporter expression

Acetaminophen (APAP) overdose is the most frequent cause of drug-induced acute liver failure. Inhibition of APAP metabolic activation and promotion in APAP disposition are important to protect against APAP-induced liver injury. Tumor suppressor p53 is traditionally recognized as a surveillance molecule to preserve genome integrity. Recent studies have emerged on discovering its functions in metabolic regulation. Our previous study reported that p53 promoted bile acid disposition and alleviated cholestastic syndrome. Here, we examined the effect of doxorubicin (Dox)-mediated p53 activation on APAP-induced hepatotoxicity in mice and revealed a novel role of p53 in regulating APAP metabolism and disposition. Histopathological and biochemical assessments demonstrated that administration of Dox (10 mg/kg/d) before APAP treatment (400 mg/kg) significantly alleviated APAP-induced hepatotoxicity. Dox treatment prevented APAP-induced GSH depletion and lipid peroxidation. p53-null mice were more susceptible to APAP-induced liver injury. Further, we found that the expression of drug-metabolizing enzymes and transporters CYPs, SULTs and MRPs was regulated by p53. Dox treatment also promoted Nrf2 activation and increased the expression of Nrf2 target genes including GSTα/μ and NQO1, which contribute to APAP detoxification. Overall, this study is the first to demonstrate the protective role of p53 in regulating APAP metabolism and disposition, which provides a potential new therapeutic target for APAP-induced liver injury.

Biomimetic trapping cocktail to screen reactive metabolites: use of an amino acid and DNA motif mixture as light/heavy isotope pairs differing in mass shift

Candidate drugs that can be metabolically transformed into reactive electrophilic products, such as epoxides, quinones, and nitroso compounds, are of special concern because subsequent covalent binding to bio-macromolecules can cause adverse drug reactions, such as allergic reactions, hepatotoxicity, and genotoxicity. Several strategies have been reported for screening reactive metabolites, such as a covalent binding assay with radioisotope-labeled drugs and a trapping method followed by LC-MS/MS analyses. Of these, a trapping method using glutathione is the most common, especially at the early stage of drug development. However, the cysteine of glutathione is not the only nucleophilic site in vivo; lysine, histidine, arginine, and DNA bases are also nucleophilic. Indeed, the glutathione trapping method tends to overlook several types of reactive metabolites, such as aldehydes, acylglucuronides, and nitroso compounds. Here, we introduce an alternate way for screening reactive metabolites as follows: A mixture of the light and heavy isotopes of simplified amino acid motifs and a DNA motif is used as a biomimetic trapping cocktail. This mixture consists of [²H₀]/[²H₃]-1-methylguanidine (arginine motif, Δ 3 Da), [²H₀]/[²H₄]-2-mercaptoethanol (cysteine motif, Δ 4 Da), [²H₀]/[²H₅]-4-methylimidazole (histidine motif, Δ 5 Da), [²H₀]/[²H₉]-n-butylamine (lysine motif, Δ 9 Da), and [¹³C₀,¹⁵N₀]/[¹³C₁,¹⁵N₂]-2'-deoxyguanosine (DNA motif, Δ 3 Da). Mass tag triggered data-dependent acquisition is used to find the characteristic doublet peaks, followed by specific identification of the light isotope peak using MS/MS. Forty-two model drugs were examined using an in vitro microsome experiment to validate the strategy. Graphical abstract Biomimetic trapping cocktail to screen reactive metabolites.

Detoxifying effect of pyridoxine on acetaminophen-induced hepatotoxicity via suppressing oxidative stress injury

The detoxifying effect of pyridoxine against acetaminophen (APAP)-induced hepatotoxicity was investigated. HepG2 cells were co-treated with APAP and pyridoxine to compare with betaine or methionine for 24 h. LDH, ALT and AST activities were measured to determine direct cells damage in vitro and in vivo. Lipid peroxidation, antioxidant enzymes activity, and glutathione level were measured. Cytochrome c releaseand procaspase-3, cleaved caspase-3, Bcl-2, or Bax protein levels were measured to determine APAP-induced apoptotic cell death. Pyridoxine treatment significantly increased cell viability and decreased leakage of LDH activity against APAP-induced hepatotoxicity in HepG2 cells. ALT and AST activities were dose-dependently reduced by pyridoxine treatment compared to APAP-treated group. Significant increases in activities of GST and GPx were observed after co-treatment with APAP and pyridoxine. Although APAP-induced Nrf2 and HO-1 expression levels were gradually reduced in HepG2 cells by pyridoxine treatment, induction of antioxidant enzymes activities were dose-dependently increased. These protected effects of pyridoxine against APAP-induced hepatoxicity were closely associated with suppression of APAP-induced oxidative stress and apoptotic cell death in HepG2 cells. These data indicated that the protective action of pyridoxine against hepatic cell injuries was involved in the direct antioxidant activity which provides a pivotal mechanism for its potential hepatoprotective action.

Exogenous recombinant human thioredoxin-1 prevents acetaminophen-induced liver injury by scavenging oxidative stressors, restoring the thioredoxin-1 system and inhibiting receptor interacting protein-3 overexpression

Thioredoxin-1 (Trx-1) is a potent therapeutic agent against a variety of diseases because of its actions as an antioxidant and regulator of apoptosis. N-acetyl-p-aminophenol (APAP), commonly known as acetaminophen, generates excessive oxidative stress and triggers hepatocyte cell death, exemplified by regulated necrosis. In the present study, we investigated whether APAP-induced liver injury in a mouse model is associated with "necroptosis," and if pretreatment with recombinant Trx-1 prevents the hepatic injury caused by APAP overdose. We also explored the mechanism underlying the preventive action of Trx-1 against APAP-induced hepatic injury. In a prevention study, C3H/he mice received different doses (0, 10, 50 or 100 mg kg^-1 body weight) of recombinant human Trx-1 intraperitoneally, followed by a single oral dose of 300 mg kg^-1 of APAP. In this experimental paradigm, liver injury and lethality were markedly decreased in rhTrx-1-pretreated mice. In survival experiments, mice received rhTrx-1 followed by oral administration of a lethal dose of APAP. APAP overdose caused a series of liver toxicity-associated events, beginning with overexpression of c-fos, excessive production of reactive oxygen species and reactive nitrogen species (RNS) and leading to decreased endogenous Trx-1 expression and activation of JNK signaling pathways. Pretreatment with rhTrx-1 inhibited all of these toxicological manifestations of APAP. In addition, rhTrx-1 significantly reduced the expression of RIP-3, a critical necrosome component. Taken together, our findings indicate that rhTrx-1 prevents APAP-induced liver injury through multiple action mechanisms, including scavenging reactive oxygen species and reactive nitrogen species, restoring endogenous Trx-1 levels and inhibiting RIP-3 overexpression.

High-content imaging assays on a miniaturized 3D cell culture platform

The majority of high-content imaging (HCI) assays have been performed on two-dimensional (2D) cell monolayers for its convenience and throughput. However, 2D-cultured cell models often do not represent the in vivo characteristics accurately and therefore reduce the predictability of drug toxicity/efficacy in vivo. Recently, three-dimensional (3D) cell-based HCI assays have been demonstrated to improve predictability, but its use is limited due to difficulty in maneuverability and low throughput in cell imaging. To alleviate these issues, we have developed miniaturized 3D cell culture on a micropillar/microwell chip and demonstrated high-throughput HCI assays for mechanistic toxicity. Briefly, Hep3B human hepatoma cell line was encapsulated in a mixture of alginate and fibrin gel on the micropillar chip, cultured in 3D, and exposed to six model compounds in the microwell chip for rapidly assessing mechanistic hepatotoxicity. Several toxicity parameters, including DNA damage, mitochondrial impairment, intracellular glutathione level, and cell membrane integrity were measured on the chip, and the IC₅₀ values of the compounds at different readouts were determined to investigate the mechanism of toxicity. Overall, the Z' factors were between 0.6 and 0.8 for the HCI assays, and the coefficient of variation (CV) were below 20%. These results indicate high robustness and reproducibility of the HCI assays established on the miniaturized 3D cell culture chip. In addition, it was possible to determine the predominant mechanism of toxicity using the 3D HCI assays. Therefore, our miniaturized 3D cell culture coupled with HCI assays has great potential for high-throughput screening (HTS) of compounds and mechanistic toxicity profiling.

Ethyl pyruvate attenuates acetaminophen-induced liver injury and prevents cellular injury induced by N-acetyl-p-benzoquinone imine

Acetaminophen, a common analgesic/antipyretic, is a frequent cause of acute liver failure in Western countries. The development of an effective cure against acetaminophen hepatotoxicity is crucial. Ethyl pyruvate, an ethyl ester derivative of pyruvic acid, has been identified as a possible candidate against acetaminophen hepatotoxicity in animal experiments. However, the mode of the hepatoprotective action of ethyl pyruvate remains unclear. We examined the hepatoprotective effect of ethyl pyruvate against hepatocyte injury and oxidative stress in a mouse model of acetaminophen hepatotoxicity. In addition, to examine whether ethyl pyruvate has direct hepatocellular protection against acetaminophen hepatotoxicity to counteract the influence of inflammatory cells, such as macrophages, we examined the effects of ethyl pyruvate on cellular injury induced by N-acetyl-p-benzoquinone imine, a toxic metabolite of acetaminophen, in a human hepatocyte cell line, HepG2 cells. Treatment with ethyl pyruvate significantly prevented increases in serum transaminase levels and hepatic centrilobular necrosis induced with an acetaminophen overdose in mice in a dose-dependent manner. Although hepatic DNA fragmentation induced by acetaminophen was also attenuated with ethyl pyruvate, nitrotyrosine formation was not inhibited. Ehyl pyruvate significantly attenuated mitochondria dehydrogenase inactivity induced by N-acetyl-p-benzoquinone imine in HepG2 cells. The attenuating effect was also observed in a rat hepatocyte cell line. Increases in annexin V and propidium iodide-stained cells induced by N-acetyl-p-benzoquinone imine were prevented with ethyl pyruvate in HepG2 cells. Pyruvic acid, a parent compound of ethyl pyruvate, tended to attenuate these changes. The results indicate that ethyl pyruvate has direct hepatocellular protection against N-acetyl-p-benzoquinone imine induced injury observed in acetaminophen overdose. The in vivo and in vitro results suggest that ethyl pyruvate attenuates acetaminophen-induced liver injury via, at least in part, its cellular protective potential.

N-acetylcysteine and prednisolone treatment improved serum biochemistries in suspected flupirtine cases of severe idiosyncratic liver injury

BACKGROUND & AIMS

The analgesic flupirtine has been linked to cases of severe idiosyncratic drug-induced liver injury (sFILI). We therefore examined whether N-acetylcysteine (NAC) and glucocorticoid therapy is effective in the management of sFILI.

METHODS

In a retrospective cohort study efficacy of NAC-infusion and oral prednisolone treatments on liver-function-tests (LFTs) and clinical outcome of 21 sFILI cases was evaluated by comparing it to an external cohort of 30 sFILI cases not receiving the antidote. LFTs were also assayed in human hepatocyte cultures treated with flupirtine for 96 hours. Additionally, modulation of glutathione stores in cultures of human hepatocytes treated with 80 drugs was investigated.

RESULTS

Upon admission, patients presented Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and bilirubin elevations of up to 90-, 35- and 30-fold of upper limits of normal (ULN) respectively. The average INR was 2.2, and 50% of patients had a high Model for end-stage liver disease (MELD) score of ≥25 and included 5 cases of 28-32. The combined NAC/prednisolone treatment was well tolerated and led to significant ALT, AST and INR improvements within 2 weeks. However, the hyperbilirubinaemia resolved slowly. Two patients with late start of NAC/prednisolone treatment developed hepatic encephalopathy and required liver transplantation; the remaining patients recovered without long-term sequela. Based on serum biochemistries sFILI cases resolved more rapidly (P < .01) when compared to untreated sFILI patients and included a case with fatal outcome. Additionally, in vitro studies revealed glutathione depletion as a common culprit for drugs with liver liabilities.

CONCLUSIONS

Based on these initial findings a prospective randomized clinical trial (RCT) is needed to confirm safety and efficacy of NAC/prednisolone treatment in sFILI.

Co-ingestion of aspirin and acetaminophen promoting fulminant liver failure: A critical review of Reye syndrome in the current perspective at the dawn of the 21st century

In the paediatric population, there is some evidence of possible interaction, synergism, and co-toxicity of aspirin and acetaminophen. The toxicity of salicylates such as aspirin in this population is well known and documented, specifically in the form of Reye syndrome. The possible toxic synergism with aspirin and acetaminophen, however, is not previously described; though case reports suggest such co-toxicities with low levels of aspirin and other compounds can exist. In vitro studies into mechanistic processes of salicylate toxicity propose that there is a bi-directional link and potentiation with glutathione (GSH) depletion and salicylate toxicity. Data may suggest a plausible explanation for salicylate and acetaminophen toxic synergism. Further studies investigating this potential toxic synergism are warranted. Given the lack of awareness in the clinical community about potential toxic synergism between these relatively common medications, caution is advised in the co-administration of these drugs, particularly in communities using natural or alternative therapy.

Cell-based assay using glutathione-depleted HepaRG and HepG2 human liver cells for predicting drug-induced liver injury

Immortalized liver cells have been used for evaluating the toxicity of compounds; however, excessive glutathione is considered to lessen cytotoxicity. In this study, we compared the effects of glutathione depletion on cytotoxicities of drugs using HepaRG and HepG2 cells, which express and lack drug-metabolizing enzymes, respectively, for predicting drug-induced liver injury (DILI) risks. These cells were pre-incubated with L-buthionine-S,R-sulfoximine (BSO) and then exposed to 34 test compounds with various DILI risks for 24 h. ATP level exhibited the highest predictability of DILI among tested parameters. BSO treatment rendered cells susceptible to drug-induced cytotoxicity when evaluated by cell viability and caspase 3/7 activity with the sensitivity of cell viability from 50% in non-treated HepaRG cells to 71% in BSO-treated HepaRG cells. These results indicate that cytotoxicity assays using GSH-depleted HepaRG cells improve the predictability of DILI risks. However, HepaRG cells were not always superior to HepG2 cells when assessed by ATP level. The combination of HepG2 and HepaRG cells index produced the best prediction in the cases of caspase 3/7 acitivity and ATP level. In conclusions, the developed highly sensitive cell-based assay using GSH-reduced cells would be useful for predicting potential DILI risks at an early stage of drug development.

Increased risk of congestive heart failure in patients with acetaminophen poisoning: A nationwide cohort study

Acetaminophen poisoning increases cytochrome P450 2E1 expression and reactive oxygen species production, which may lead to maladaptive myocardial remodeling and congestive heart failure (CHF). We conducted a nationwide cohort study to investigate the incidence and risk of CHF in patients with acetaminophen poisoning. We identified a cohort of adult patients with newly diagnosed acetaminophen poisoning in the inpatient claims of the Taiwan National Health Insurance Research Database for the 1998-2011 period. A comparison cohort was frequency matched at a 4:1 ratio for sex, age and index year. All patients were followed up until the occurrence of CHF, withdrawal from the National Health Insurance program, or December 31, 2011. Cox proportional hazards models were employed to calculate the risk of CHF in the acetaminophen poisoning cohort compared with the comparison cohort, and the hazard ratios with 95% confidence intervals are presented. A total of 3546 and 14 184 patients with and without acetaminophen poisoning were followed up for a total of 25 856 and 102 119 person-years, respectively. The overall incidence of CHF was higher in the acetaminophen poisoning cohort than in the comparison cohort (8.12 vs. 5.19 per 10 000 person-years). After adjustment for covariates, the acetaminophen poisoning cohort exhibited a 1.59-fold higher risk of CHF (adjusted hazard ratio = 1.59; 95% confidence interval = 1.43-1.75) than did the comparison cohort. Patients with acetaminophen poisoning exhibited a significantly higher risk of CHF compared with the comparison cohort. Clinicians should follow up heart function in patients with acetaminophen poisoning.

Acetaminophen Poisoning May Increase Coronary Artery Disease Risk: A Nationwide Cohort Study

The purpose of this nationwide cohort study was to investigate the incidence and risk of coronary artery disease (CAD) in patients with acetaminophen (APAP) poisoning. We identified the patients with APAP poisoning and randomly selected comparison patients according to a 1:4 ratio, matching them by age, sex, and the index year using data from the National Health Insurance Research Database from 2000 to 2010. We traced both cohorts until a diagnosis of CAD, loss to follow-up, or the end of 2011. In total, 2723 patients with APAP poisoning and 10,892 comparison patients have followed. The incidence rate of CAD was higher in the APAP poisoning cohort than in the non-APAP poisoning cohort (1.53 vs 0.87 per 1000 patient-years). The APAP poisoning cohort exhibited a 1.85-fold higher risk of CAD than did the non-APAP poisoning cohort (adjusted hazard ratio [aHR] 1.85; 95% confidence interval [CI] 1.16-2.94). Male sex, advanced age, and hypertension were independently associated with CAD risk. The risk of CAD was considerably higher within 3 years following APAP poisoning (aHR 2.73; 95% CI 1.31-5.69). This study indicated that APAP poisoning may increase risk of CAD development.

Discovery of indolylpiperazinylpyrimidines with dual-target profiles at adenosine A2A and dopamine D2 receptors for Parkinson's disease treatment

Parkinson's disease (PD) is a neurodegenerative disorder characterized by progressive loss of dopaminergic neurons in the substantia nigra of the human brain, leading to depletion of dopamine production. Dopamine replacement therapy remains the mainstay for attenuation of PD symptoms. Nonetheless, the potential benefit of current pharmacotherapies is mostly limited by adverse side effects, such as drug-induced dyskinesia, motor fluctuations and psychosis. Non-dopaminergic receptors, such as human A2A adenosine receptors, have emerged as important therapeutic targets in potentiating therapeutic effects and reducing the unwanted side effects. In this study, new chemical entities targeting both human A2A adenosine receptor and dopamine D2 receptor were designed and evaluated. Two computational methods, namely support vector machine (SVM) models and Tanimoto similarity-based clustering analysis, were integrated for the identification of compounds containing indole-piperazine-pyrimidine (IPP) scaffold. Subsequent synthesis and testing resulted in compounds 5 and 6, which acted as human A2A adenosine receptor binders in the radioligand competition assay (Ki = 8.7-11.2 μM) as well as human dopamine D2 receptor binders in the artificial cell membrane assay (EC50 = 22.5-40.2 μM). Moreover, compound 5 showed improvement in movement and mitigation of the loss of dopaminergic neurons in Drosophila models of PD. Furthermore, in vitro toxicity studies on compounds 5 and 6 did not reveal any mutagenicity (up to 100 μM), hepatotoxicity (up to 30 μM) or cardiotoxicity (up to 30 μM).

Seabuckthorn berry polysaccharide extracts protect against acetaminophen induced hepatotoxicity in mice via activating the Nrf-2/HO-1-SOD-2 signaling pathway

BACKGROUND

Oxidative stress is concomitant with acetaminophen (APAP)-induced hepatotoxicity, which has been highlighted as therapeutic targets for such diseases. The berries of Seabuckthorn (Hippophae rhamnoides L.) have been traditionally used in Tibetan medicine for thousands of years. The effect of Seabuckthorn berry polysaccharide on drug- induced liver injury (DILI) has not yet been elucidated.

PURPOSE

This study aims to investigate the protective effects and mechanisms of Seabuckthorn polysaccharide (SP) against APAP-induced hepatotoxicity.

STUDY DESIGN

Sixty C57BL/6 mice were randomly divided into six groups (n = 10 per group), namely the control group (Ctrl), APAP-induced-liver injury group (APAP), NAC pretreated group (NAC), 100 mg/kg SP pretreated group (APAP/SP100), 200 mg/kg SP pretreated group (APAP/SP200) and 200 mg/kg SP pretreated group without APAP challenge (SP200). SP was given orally to mice for 30 consecutive days prior to APAP exposure (300 mg/kg). NAC (150 mg/kg) was administrated 1 h before APAP challenge.

METHODS

ALT and AST were detected 16 h after APAP treatment; Hepatic expression of GSH, SOD, NO, iNOS and GSH-Px were examined. The expression of p-JNK, Bcl-2/Bax, p62, Keap-1 and SOD-2 was detected by Western blotting. The expression of Nrf-2 and its target genes HO-1, GCLC and NQO-1 were analyzed by RT-PCR and Western blotting.

RESULTS

Pretreatment with SP led to decreased levels of ALT and AST in APAP mice, without affecting APAP metabolism. This was accompanied by diminished liver injuries, increased levels of GSH and GSH-Px, reduced NO and iNOS expression. SP increased the activity of SOD as well as SOD-2 expression in APAP mice. SP suppressed APAP-induced JNK phosphorylation and increased the ratio of Bcl-2/Bax. Furthermore, SP decreased the expression of Keap-1 and increased the nuclear expression of Nrf-2. The expression of Nrf-2 target gene HO-1 was increased by SP pretreatment in APAP mice.

CONCLUSION

SP alleviates APAP-induced hepatotoxicity. The protective effects of SP are associated with the activation of the Nrf-2/HO-1-SOD-2 signaling pathway.

A Review on Ethnopharmacological Applications, Pharmacological Activities, and Bioactive Compounds of Mangifera indica (Mango)

Mangifera indica (family Anacardiaceae), commonly known as mango, is a pharmacologically, ethnomedically, and phytochemically diverse plant. Various parts of M. indica tree have been used in traditional medicine for the treatment of different ailments, and a number of bioactive phytochemical constituents of M. indica have been reported, namely, polyphenols, terpenes, sterols, carotenoids, vitamins, and amino acids, and so forth. Several studies have proven the pharmacological potential of different parts of mango trees such as leaves, bark, fruit peel and flesh, roots, and flowers as anticancer, anti-inflammatory, antidiabetic, antioxidant, antibacterial, antifungal, anthelmintic, gastroprotective, hepatoprotective, immunomodulatory, antiplasmodial, and antihyperlipemic. In the present review, a comprehensive study on ethnopharmacological applications, pharmacological activities, and bioactive compounds of M. indica has been described.

Excess of dietary montmorillonite impairs growth performance, liver function, and antioxidant capacity in starter pigs

Montmorillonite (MMT) is widely used as a mycotoxin adsorbent in animal feeds, but its safety remains unclear. This study was conducted to investigate the safety of MMT supplementation in diets fed to starter pigs. A total of 120 32-d-old piglets (initial weight, 8.0 ± 0.9 kg) were randomly allotted into dietary treatments with graded MMT levels (0 [FS 0], 0.5% [FS 0.5], 1.0% [FS 1.0], 2.5% [FS 2.5], and 5.0% [FS 5.0]) with 6 replicate pens per treatment and 4 pigs per pen. All diets were fed for 28 d. As the MMT level increased, ADG and G:F changed in a linear and quadratic manner, while ADFI was linearly decreased ( > 0.05). Compared with FS 0, ADG, ADFI, and G:F of pigs in FS 1.0 increased ( < 0.05). However, the ADFI in pigs of FS 5.0 was lower than that in pigs of FS 0 ( < 0.05). The relative liver weight activities of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) changed in a linear and quadratic manner ( < 0.05). Compared with FS 0, pigs in FS 2.5 and FS 5.0 had a greater serum ALT ( < 0.05), while AST activity significantly increased in pigs of FS 5.0 ( < 0.05). Dietary MMT supplementation decreased serum Mg content in a linear and quadratic manner ( < 0.05), while Zn and Cu contents were linearly decreased ( < 0.05). Serum Zn and Cu contents of pigs in FS 0.5, FS 2.5, and FS 5.0 groups were lower than those in the control. Pigs fed with 2.5% and 5% MMT showed hepatic histopathological changes, including swelling, granular and vesicular degeneration, and apparent vacuolar degeneration. In addition, the content of serum total antioxidant capacity (T-AOC) and activity of glutathione peroxidase (GSH-PX) decreased in a linear and quadratic manner ( < 0.05). Compared to the control, 5.0% MMT significantly increased piglets' serum malondialdehyde (MDA) concentration and decreased GSH-PX activity ( < 0.05). T-AOC concentration in the pigs fed 2.5% and 5.0% MMT was lower than that in the control group ( < 0.05). Serum superoxide dismutase (SOD) activity changed in a quadratic manner ( < 0.05). Piglets in FS 1.0 showed a higher SOD activity when compared with the control ( < 0.05). These results indicate that supplementation of MMT higher than 1.0% can negatively affect liver structure and serum mineral content, and 5.0% MMT supplementation would also decrease feed intake, aggravate liver damage, and reduce the antioxidant capacity of starter pigs. Therefore, excess supplementation of MMT is not safe in starter pigs.

The Use of In Silico Models Within a Large Pharmaceutical Company

The present contribution describes how in silico models are applied at different stages of the drug discovery process in the pharmaceutical industry. A thorough description of the most relevant computational methods and tools is given along with an in-depth evaluation of their performance in the context of potential genotoxic impurities assessment.The challenges of predicting the outcome of highly complex studies are discussed followed by considerations on how novel ways to manage, store, share and analyze data may advance knowledge and facilitate modeling efforts.

GC-MS analysis and hepatoprotective activity of the n-hexane extract of Acrocarpus fraxinifolius leaves against paracetamol-induced hepatotoxicity in male albino rats

CONTEXT

In Egypt, the burden of liver diseases is exceptionally high.

OBJECTIVE

To investigate the components of the n-hexane extract of Acrocarpus fraxinifolius Arn. (Leguminosae) and its hepatoprotective activity against paracetamol (APAP)-induced hepatotoxicity in rats.

MATERIAL AND METHODS

TRACE GC ultra gas chromatogaphic spectrometry was used for extract analysis. Thirty albino rats were divided into six groups (five rats in each). Group 1 was the healthy control; Groups 2 and 3 were healthy treated groups (250 and 500 mg/kg b.w. of the extract, respectively) for seven days. Group 4 was hepatotoxicity control (APAP intoxicated group). Groups 5 and 6 received APAP + extract 250 and APAP + extract 500, respectively.

RESULTS

Chromatographic analysis revealed the presence of 36 components. Major compounds were α-tocopherol (18.23%), labda-8 (20)-13-dien-15-oic acid (13.15%), lupeol (11.93%), phytol (10.95%) and squalene (7.19%). In the acute oral toxicity study, the mortality rates and behavioural signs of toxicity were zero in all groups (doses from 0 to 5 g/kg b.w. of A. fraxinifolius). LD₅₀ was found to be greater than 5 g/kg of the extract. Only the high dose (500 mg/kg b.w.) of extract significantly alleviated the liver relative weight (4.01 ± 0.06) and biomarkers, as serum aspartate aminotransferase (62.87 ± 1.41), alanine aminotransferase (46.74 ± 1.45), alkaline phosphatase (65.96 ± 0.74), lipid profiles (180.39 ± 3.51), bilirubin profiles (2.30 ± 0.06) and hepatic lipid peroxidation (114.20 ± 2.06), and increased body weight (11.58 ± 0.20), serum protein profile (11.09 ± 0.46) and hepatic total antioxidant capacity (23.78 ± 0.66) in APAP-induced hepatotoxicity in rats.

CONCLUSION

Our study proves the antihepatotoxic/antioxidant efficacies of A. fraxinifolius hexane extract.