Acetaminophen-induced hepatotoxicity

Hepatoprotective effects of Gamisoyo-san against acetaminophen-induced liver injuries

Background

Acetaminophen (N-acetyl-p-aminophenol, APAP) is a safe and effective analgesic at therapeutic dosage. However, APAP overdose is a major cause of acute liver injury. Gamisoyo-san (GMSYS; Jiaweixiaoyao-san in Chinese, Kamishoyo-san in Japanese), a traditional herbal formula, is used to treat phlegm and cough in Korea. The purpose of this study was to investigate the hepatoprotective effect of GMSYS against APAP-induced liver injury in vitro and in vivo.

Methods

We evaluated the effect of GMSYS on APAP-induced hepatotoxicity by measuring cell viability in murine BNL CL.2 liver cells. Additionally, BALB/c mice were orally administered with GMSYS once daily for 7 days. Eighteen hours after the last administration, mice were intraperitoneally injected with 200 mg/kg APAP. Plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, hepatic antioxidants, and histological changes were examined.

Results

Pretreatment with GMSYS attenuated the decrease in cell viability induced by APAP in BNL CL.2 cells. In mice, pre-administration with GMSYS alleviated APAP-induced hepatotoxicity by decreasing plasma ALT and AST activities and hepatic malondialdehyde, and by increasing the total glutathione (GSH)/reduced GSH ratio and the activities of several antioxidants such as superoxide dismutase, catalase, GSH peroxidase, GSH reductase, GSH-S-transferase, and heme oxygenase-1.

Conclusion

GMSYS has a protective effect against APAP-induced acute liver injury by decreasing plasma transaminases and increasing antioxidants. GMSYS may be an effective candidate for the prevention of acute liver injury.

Paracetamol-induced metabolic and cardiovascular changes are prevented by exercise training

Paracetamol (PAR) is the most frequently consumed non-prescription drug, yet it is well known to induce toxicity. Here, we have evaluated the effects of exercise training on vascular dysfunction induced by PAR. Rats were distributed among four groups: (a) Sedentary; (b) Exercise; (c) Sedentary+PAR; and (d) Exercise+PAR. The exercise comprised swimming 50 min/d, 5 d/wk for 6 weeks (+PAR in the last 2 weeks, at 400 mg/kg/d/p.o.). After killing, the rats' blood and aortas were collected for biochemical analysis of hepatic transaminases, TBARs reaction, glutathione, glutathione reductase, SOD, and catalase. In vitro vascular relaxation was measured using acetylcholine and sodium nitroprusside in the presence or absence of tiron (an antioxidant). Vascular protein expression (eNOS and sGC) also were analysed. Increased transaminases after PAR treatment were found to be reduced by exercise. Vasodilation was impaired by PAR only in the sedentary group. Exercise prevented alterations in lipoperoxidation and glutathione levels after PAR exposure. Glutaathione reductase and SOD also were increased by PAR but were normalized in the exercised group. Catalase activity and protein expressions did not change in any group. PAR treatment caused impairment in both vasodilation and redox balance; however, exercise training prevented the vascular and redox system dysfunction induced by PAR treatment.

Dried blood microsamples: Suitable as an alternative matrix for the quantification of paracetamol-protein adducts?

Paracetamol (acetaminophen, APAP) is the most frequently used analgesic drug worldwide. However, patients in several specific populations can have an increased exposure to toxic APAP metabolites. Therefore, APAP-protein adducts have been proposed as an alternative marker for the assessment of APAP intoxications and as an effective tool to study and steer APAP treatment in patients with an increased risk of APAP-induced liver damage. These adducts have been determined in plasma or serum as a matrix. Blood microsampling allows the determination of a variety of analytes, including protein adducts, in a drop of blood, facilitating convenient follow-up of patients in a home-sampling context, as well as repeated sampling of pediatric patients. We therefore evaluated the use of blood-based volumetric microsamples for the quantification of APAP-protein adducts. Quantitative methods for the determination of APAP-protein adducts in dried blood and dried plasma volumetric absorptive microsamples were developed and validated. Also a preliminary evaluation of pediatric patient dried blood microsamples was conducted. Method validation encompassed the evaluation of selectivity, carry over, calibration model, accuracy and precision, matrix effect, recovery and the effect of the hematocrit on the recovery, dilution integrity, and stability. All pre-set acceptance criteria were met, except for stability. Spiking of blank blood with APAP revealed a concentration-dependent ex vivo formation of APAP-protein adducts, resulting in a response for the measurand APAP-Cys, with an apparent role for the red blood cell fraction. Analysis of authentic samples, following intake of APAP at therapeutic dosing, revealed much higher APAP-Cys concentrations in dried blood vs. dried plasma samples, making interpretation of the results in the context of published intervals difficult. In addition, in contrast to what was observed during method validation, the data obtained for the patient samples showed a high and unacceptable variation. We conclude that, for a combination of reasons, dried blood is not a suitable matrix for the quantification of APAP-protein adducts via the measurement of the APAP-Cys digestion product. The collection of plasma or serum, either in the form of a liquid sample or a dried microsample for this purpose is advised.

Acetaminophen Oxidation and Inflammatory Markers - A Review of Hepatic Molecular Mechanisms and Preclinical Studies

Acetaminophen is a widely used analgesic for pain management, especially useful in chronic diseases, such as rheumatoid arthritis. However, easy access to this medicine has increased the occurrence of episodes of poisoning. Patients often develop severe liver damage, which may quickly lead to death. Consequently, numerous studies have been conducted to identify new biomarkers that allow the prediction of the degree of acetaminophen intoxication and thus intervene in a timely manner to save patients' lives. This review highlights the main mechanisms of the induction and progression of liver damage arising from acetaminophen poisoning. In addition, we have discussed the possibility of using new clinical biomarkers for detecting acetaminophen poisoning.

Organ-Specific Screening for Protein Damage Using Magnetic Bead Bioreactors and LC-MS/MS

A new 96-well plate methodology for fast, enzyme-multiplexed screening for metabolite-protein adducts was developed. Magnetic beads coated with metabolic enzymes were used to make potentially reactive metabolites that can react with test protein in the wells, followed by sample workup in multiple 96-well filter plates for LC-MS/MS analysis. Incorporation of human microsomes from multiple organs and selected supersomes of single cytochrome P450 (cyt P450) enzymes on the magnetic beads provided a broad spectrum of metabolic enzymes. The reacted protein was then isolated, denatured, reduced, alkylated, and digested, and peptides were collected in a sequence of 96-well filter plates for analysis. Method performance was evaluated by trapping acetaminophen reactive metabolite N-acetyl-p-benzoquinoneimine (NAPQI) with human glutathione S-transferase pi (hGSTP), human serum albumin (HSA), and bovine serum albumin (BSA) as model target proteins. Relative amounts of acetaminophen metabolite and hGSTP adducts were compared with 10 different cyt P450 enzymes. Human liver microsomes and CYP1A2 supersomes showed the highest bioactivation rate for adduct formation, in which all four cysteines of hGSTP reacted with NAPQI. Eight cysteines of HSA and four cysteines of BSA have been detected to react with NAPQI. This method has the potential for fast multienzyme protein adduct screening with high efficiency and accuracy.

Suppression of iron mobilization from lysosomes to mitochondria attenuates liver injury after acetaminophen overdose in vivo in mice: Protection by minocycline

Acetaminophen (APAP) overdose causes hepatotoxicity involving mitochondrial dysfunction. Previous studies showed that translocation of Fe²⁺ from lysosomes into mitochondria by the mitochondrial Ca²⁺ uniporter (MCU) promotes the mitochondrial permeability transition (MPT) after APAP. Here, our Aim was to assess protection by iron chelation and MCU inhibition against APAP hepatotoxicity in mice. C57BL/6 mice and hepatocytes were administered toxic doses of APAP with and without starch-desferal (an iron chelator), minocycline (MCU inhibitor), or N-acetylcysteine (NAC). In mice, starch-desferal and minocycline pretreatment decreased ALT and liver necrosis after APAP by >60%. At 24 h after APAP, loss of fluorescence of mitochondrial rhodamine 123 occurred in pericentral hepatocytes often accompanied by propidium iodide labeling, indicating mitochondrial depolarization and cell death. Starch-desferal and minocycline pretreatment decreased mitochondrial depolarization and cell death by more than half. In cultured hepatocytes, cell killing at 10 h after APAP decreased from 83% to 49%, 35% and 27%, respectively, by 1 h posttreatment with minocycline, NAC, and minocycline plus NAC. With 4 h posttreatment in vivo, minocycline and minocycline plus NAC decreased ALT and necrosis by ~20% and ~50%, respectively, but NAC alone was not effective. In conclusion, minocycline and starch-desferal decrease mitochondrial dysfunction and severe liver injury after APAP overdose, suggesting that the MPT is likely triggered by iron uptake into mitochondria through MCU. In vivo, minocycline and minocycline plus NAC posttreatment after APAP protect at later time points than NAC alone, indicating that minocycline has a longer window of efficacy than NAC.

Hepatotoxicity and nephrotoxicity following long-term prenatal exposure of paracetamol in the neonatal rat: is betaine protective?

Background

Paracetamol is one of the widely used antipyretic and analgesic drug around the world. Many researchers showed that paracetamol caused to hepatotoxicity or nephrotoxicity.

Objective

In the present study, we aimed to determine whether betaine has protective effects on hepatotoxicity and nephrotoxicity in neonate rats, following to long term maternal paracetamol exposure.

Materials and methods

Randomly chosen neonates, from the neonate pools, were divided into three groups; Control (n=13), APAP (n=13), and APAP+Betaine (n=13). Physiological saline, paracetamol (30 mg/kg/day), and paracetamol (30 mg/kg/day)+betaine (800 mg/kg/day) were orally administered to the relevant groups during the pregnancy period (approximately 21 day). Following to the birth, neonates were decapitated under anaesthesia and tissue samples were taken for biochemical and histological analyses.

Results

The statistical analysis showed that, malondialdehyde and nitric oxide levels increase significantly in APAP group, while paraoxonase, arylesterase activity and glutathione levels decrease. After the betaine administration, glutathione levels, paraoxonase and arylesterase activities increased while malondialdehyde and nitric oxide levels decreased in APAP+betaine group. These biochemical findings also were supported by histological results.

Conclusion

In this study, our biochemical and histological findings indicate that betaine can protect the tissue injury caused by paracetamol.

Adverse drug reactions in dentistry

An adverse drug reaction (ADR) is an undesirable effect of a drug. ADRs are possible with any medication that is prescribed or administered in the dental office. While most pharmacological agents in use today have favourable drug profiles and are relatively safe, the prudent clinician must be aware of the potential ADRs that can occur and be prepared to manage any complications. Here we review the most commonly used agents in dentistry, namely local anaesthetics, sedatives, analgesics and antibiotics, and their ADRs and management.

Optimization extraction and characterization of Artemisia ordosica polysaccharide and its beneficial effects on antioxidant function and gut microbiota in rats

In this study, a novel polysaccharide was isolated from Artemisia ordosica by water-extraction-ethanol-precipitation method. The optimal extraction conditions of Artemisia ordosica polysaccharide (AOP) were determined by single factor investigation and response surface methodology optimization, and were shown as follows: a liquid–solid ratio of 15.4 : 1 mL g⁻¹, extraction time of 4.3 h, extraction temperature of 60 °C. Under the optimal conditions, the extraction yield and the sugar content of the AOP were 5.56% and 52.65%. Gel permeation chromatography coupled to multi-angle laser light scattering, a refractive index detection system and ion-exchange chromatography were used to determine the characterization of AOP. These results indicated that AOP, with a molecular weight of 2.1 kDa (62.6%) and 1.5 kDa (37.4%), had narrow polydispersity and rod conformations, and was composed of arabinose, galactose, glucose, xylose, mannose, galacturonic acid and glucuronic acid with molar ratio of 6.87 : 10.67 : 54.13 : 2.49 : 18.37 : 4.83 : 2.64 : 2.64. In addition, AOP exerted antioxidant ability in vitro and in vivo (rats). Moreover, AOP significantly modulated the composition of cecal microbiota population. Therefore, AOP is expected to be a functional ingredient for health improvement through improving antioxidant ability and modulating gut health.

Artemisia ordosica polysaccharide is expected to be functional ingredient for health improvement through improving antioxidant ability and modulating gut health.

Medicinal Thiols: Current Status and New Perspectives

The thiol (-SH) functional group is found in a number of drug compounds and confers a unique combination of useful properties. Thiol-containing drugs can reduce radicals and other toxic electrophiles, restore cellular thiol pools, and form stable complexes with heavy metals such as lead, arsenic, and copper. Thus, thiols can treat a variety of conditions by serving as radical scavengers, GSH prodrugs, or metal chelators. Many of the compounds discussed here have been in use for decades, yet continued exploration of their properties has yielded new understanding in recent years, which can be used to optimize their clinical application and provide insights into the development of new treatments. The purpose of this narrative review is to highlight the biochemistry of currently used thiol drugs within the context of developments reported in the last five years. More specifically, this review focuses on thiol drugs that represent the standard of care for their associated conditions, including N-acetylcysteine, 2,3-meso-dimercaptosuccinic acid, British anti-Lewisite, D-penicillamine, amifostine, and others. Reports of novel dosing regimens, delivery strategies, and clinical applications for these compounds were examined with an eye toward emerging approaches to address a wide range of medical conditions in the future.

PYP1-4 peptide from Pyropia yezoensis protects against acetaminophen-induced hepatotoxicity in HepG2 cells

Acetaminophen (APAP) is a widely used analgesic and antipyretic. It is safe at normal treatment doses; however, APAP overdose is a major cause of acute liver and kidney failure. A variety of methods to reduce the damage caused by APAP overdose have previously been evaluated. The protein-rich seaweed Pyropia yezoensis has antioxidant, antitumor and anti-inflammatory activities, and protects against cytotoxicity. However, little is known regarding the protective effects of P. yezoensis peptide against APAP-induced hepatotoxicity. The present study investigated the ability of P. yezoensis peptide (PYP1-4) to ameliorate the damage caused by APAP-induced hepatotoxicity using HepG2 as the model cell line in addition to the signaling pathways involved. Briefly, cell viability, nitric oxide, reactive oxygen species and apoptosis assays were performed in conjunction with western blot analysis and reverse transcription-quantitative PCR. First, the present study revealed the minimum toxic concentration of APAP (15 mM) and the resting concentration of PYP1-4 (0–500 ng/ml). Administration of PYP1-4 to APAP-induced cells decreased the nitric oxide and reactive oxygen species levels, and restored the levels of antioxidant-associated proteins (catalase, heme oxygenase 1, superoxide dismutase 2 and quinone oxidoreductase 1). PYP1-4 increased the translocation of nuclear factor, erythroid 2 like 2 to the nucleus and the activities of glycogen synthase kinase-3β, Akt and AMP-activated protein kinase. In addition, APAP induced apoptosis; however, PYP1-4 inhibited apoptosis by modulating the levels of pro-apoptotic markers (Bad), anti-apoptotic markers (Bcl-2 and BH3 interacting domain death agonist), caspases and poly (ADP-ribose) polymerase 1. Subsequently, the insulin-like growth factor 1 receptor signaling pathway was investigated to determine whether PYP1-4 treatment restored the levels of cell growth-associated factors during APAP-induced hepatotoxicity. PYP1-4 treatment impacted the levels of components of the insulin receptor substrate 1/PI3K/Akt and Ras/Raf/ERK signaling pathways, and promoted cell survival. Therefore, the P. yezoensis peptide PYP1-4 may be useful for preventing APAP-induced hepatotoxicity.

Population Pharmacokinetic Modeling of Acetaminophen Protein Adducts in Adults and Children

Acetaminophen protein adducts (adducts) are a well-established biomarker to diagnose acetaminophen toxicity. To date, the quantitative relationship between acetaminophen exposure, which drives adduct formation, and adduct exposure remains to be established. Our study characterized the adduct formation and disposition in adults using the approach of population parent-metabolite modeling. It demonstrated formation-limited pharmacokinetics (PK) for adducts in healthy subjects. This finding expands the existing knowledge on adduct PK that showed an apparent long elimination half-life. We then allometrically scaled the adduct PK model to children, simulated the adduct profiles, and compared these simulated profiles with those observed in an independent cohort of children. The scaled model significantly overpredicted the adduct concentrations in children early on in treatment and underpredicted concentrations following repeated acetaminophen doses. These results suggest that children demonstrate different adduct PK behavior from that of adults, most likely because of increased reactive metabolite detoxification in children. In summary, we described the first PK model linking acetaminophen and acetaminophen protein adduct concentrations, which provides a semimechanistic understanding of varying profiles of adduct exposure in adults and children.

Aged Citrus Peel (Chenpi) Prevents Acetaminophen-Induced Hepatotoxicity by Epigenetically Regulating Nrf2 Pathway

Excessive consumption of analgesic drug acetaminophen (APAP) can cause severe oxidative stress-mediated liver injury. Here, we investigated the protective effect and mechanism of aged citrus peel (Chenpi, CP), a Chinese herb usually used in foods in Asia, against APAP-induced hepatotoxicity. CP water (CP-WE), ethanolic (CP-EE), and water extraction residue ethanolic (CP-WREE) extracts were prepared. We found that CP-WREE contained higher content of bioactive flavonoids, including narirutin, nobiletin, and tangeretin, and more effectively enhanced the Nrf2 pathway in ARE-luciferase reporter gene transfected human HepG2-C8 cells. In mouse AML-12 hepatocytes, CP-WREE minimized APAP-induced damage and lipid peroxidation and increased mRNA and protein expressions of Nrf2 and its downstream defense enzymes (HO-1, NQO1, and UGT1A). CP-WREE also downregulated HDACs and DNMTs, upregulated KDMs, and increased the unmethylated Nrf2 promoter level. Additionally, CP-WREE blocked in vitro DNA methyltransferase activity. Taken together, CP-WREE might attenuate oxidative stress-induced hepatotoxicity through epigenetically regulating Nrf2-mediated cellular defense system.

Acetaminophen poisoning-induced heart injury: a case-based review

PURPOSE

Acetaminophen (Paracetamol, APAP) poisoning is frequently implicated in self-harm. Cases of acetaminophen-associated cardiotoxicity are rare in relation to the number of patients with acetaminophen poisoning. A review of acetaminophen cardiotoxicity in 1996 concluded that there was no decisive evidence demonstrating that acetaminophen overdose has a cardiotoxic effect. This review study aimed to determine whether acetaminophen could induce heart injury.

METHODS

We searched for keywords of acetaminophen, paracetamol, cardiotoxicity, heart injury, heart damage, myocarditis, pericarditis, myocardial infarction, and myocardial ischemia in Web of Science, PubMed, Scopus, Embase, Google Scholar, and Persian databases. The search included articles published from January 1950 to October 2018 with no language restrictions.

RESULTS

The search yielded 64 citations in English; 36 of the articles were excluded as they were not relevant; 5 articles were excluded since they were duplicates, leaving 23 articles. Full-text articles of the 23 citations were obtained and reviewed. Myocardial infarction, heart dysfunction and failure, cardiac arrhythmias, pericarditis, heart cell necrosis, and sudden cardiac death were reported in acetaminophen overdose.

CONCLUSIONS

Ddysrhythmias, heart failure, and various other cardiac effects could occur following acetaminophen induced hepatic failure. However, the evidence for direct injury on cardiac tissue is weak. Graphical abstract Potential mechanisms for cardiotoxicity of acetaminophen.

PGC-1β Induces Susceptibility To Acetaminophen-Driven Acute Liver Failure

Acetaminophen (APAP) is a worldwide commonly used painkiller drug. However, high doses of APAP can lead to acute hepatic failure and, in some cases, death. Previous studies indicated that different factors, including life-style and metabolic diseases, could predispose to the risk of APAP-induced liver failure. However, the molecular process that could favor APAP hepatotoxicity remains understood. Here, we reported that a short-term high fat-enriched diet worsens APAP-induced liver damage, by promoting liver accumulation of lipids that induces the activation of peroxisome proliferator-activated receptor gamma coactivator 1-beta (PGC-1β). Therefore, we challenged mice with hepatic-specific PGC-1β overexpression on a chow diet with a subtoxic dose of APAP and we found that PGC-1β overexpression renders the liver more sensitive to APAP damage, mainly due to intense oxidative stress, finally ending up with liver necrosis and mice death. Overall, our results indicated that during high fat feeding, PGC-1β adversely influences the ability of the liver to overcome APAP toxicity by orchestrating different metabolic pathways that finally lead to fatal outcome.

CXCL9 regulates acetaminophen-induced liver injury via CXCR3

Drug-induced liver injury has become a serious public health problem. Although the mechanism of acetaminophen (APAP)-induced liver injury has been studied for decades it has not been fully elucidated. In-depth study into the mechanisms underlying APAP-induced liver injury may provide useful information for more effective prevention and treatment. In the present study, the role of C-X-C motif chemokine ligand-9 (CXCL9) in APAP-induced liver injury was investigated thus providing a novel direction for the prevention and treatment of drug hepatitis. A total of 20 fasting male patients ingested APAP tablets at Nanjing First Hospital. In addition, wild type (WT) mice were treated with 250 mg/kg APAP or isodose PBS for 1, 3, 6 and 12 h, respectively. Results from reverse-transcription-quantitative polymerase chain reaction analyses demonstrated that CXCL9 mRNA levels were increased in the blood of patients who took APAP in a fasting state and in the livers of APAP-treated WT mice, compared with their respective controls. Hepatocyte apoptosis in the liver tissue of APAP-treated mice decreased following administration of a CXCL9 neutralizing antibody. Caspase-3, caspase-8 and phosphorylated-AKT (S437) were activated in primary hepatocytes isolated from WT mice following CXCL9 treatment. However, no significant differences in expression of caspase-3, caspase-8 and p-AKT (S437) were detected in hepatocytes isolated from C-X-C motif chemokine receptor 3 (CXCR3)^−/− mice following CXCL9 treatment. After CXCL9 administration, WT mice exhibited higher serum levels of aspartate transaminase and increased caspase-3 and caspase-8 activity in liver tissue compared with controls. The same trends were not observed in CXCR3^−/− mice. In conclusion, CXCL9 regulated APAP-induced liver injury through stimulation of hepatocyte apoptosis via binding to CXCR3. These findings provide a novel prevention and treatment strategy for DILI.

Suppression of acetaminophen-induced hepatocyte ultrastructural alterations in rats using a combination of resveratrol and quercetin

Ingestion of a toxic dose of the analgesic drug, acetaminophen (also called paracetamol or APAP), is among the most common causes of acute liver injury in humans. We tested the hypothesis that the combined polyphenolic compounds, resveratrol (RES) and quercetin (QUR), can substantially protect against hepatocyte ultrastructural damage induced by a toxic dose of APAP in a rat model of APAP-induced acute liver injury. The model group of rats received a single dose of APAP (2 g/kg), whereas the protective group of rats was pretreated for 7 days with combined doses of RES (30 mg/kg) and QUR (50 mg/kg) before being given a single dose of APAP. All rats were then sacrificed 24 hours post APAP ingestion. Harvested liver tissues were prepared for transmission electron microscopy (TEM) staining, and liver homogenates were assayed for biomarkers of inflammation, such as tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6), and oxidative stress, such as malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione peroxidase (GPx). In addition, blood samples were assayed for the liver injury enzyme alanine aminotransferase (ALT) as an indicator of liver damage. TEM images showed that APAP overdose induced acute liver injury as demonstrated by profound hepatocyte ultrastructural alterations, which were substantially protected by RES+QUR. In addition, APAP significantly (p < 0.05) modulated TNF-α, IL-6, MDA, SOD, GPx, and ALT biomarkers, which were completely protected by RES+QUR. Thus, RES+QUR effectively protects against APAP-induced acute liver injury in rats, possibly via the inhibition of inflammation and oxidative stress.

Histone methyltransferase G9a protects against acute liver injury through GSTP1

Acute liver injury is commonly caused by bacterial endotoxin/lipopolysaccharide (LPS), and by drug overdose such as acetaminophen (APAP). The exact role of epigenetic modification in acute liver injury remains elusive. Here, we investigated the role of histone methyltransferase G9a in LPS- or APAP overdose-induced acute liver injury. Under d-galactosamine sensitization, liver-specific G9a-deficient mice (L-G9a^−/−) exhibited 100% mortality after LPS injection, while the control and L-G9a^+/− littermates showed very mild mortality. Moreover, abrogation of hepatic G9a or inhibiting the methyltransferase activity of G9a aggravated LPS-induced liver damage. Similarly, under sublethal APAP overdose, L-G9a^−/− mice displayed more severe liver injury. Mechanistically, ablation of G9a inhibited H3K9me1 levels at the promoters of Gstp1/2, two liver detoxifying enzymes, and consequently suppressed their transcription. Notably, treating L-G9a^−/− mice with recombinant mouse GSTP1 reversed the LPS- or APAP overdose-induced liver damage. Taken together, we identify a novel beneficial role of G9a-GSTP1 axis in protecting against acute liver injury.

Precise Synthesis of GSH-Specific Fluorescent Probe for Hepatotoxicity Assessment Guided by Theoretical Calculation

Drug-induced hepatotoxicity is the main cause of acute liver injury, and its early diagnosis is indispensable in pharmacological and pathological studies. As a hepatotoxicity indicator, the GSH distribution in the liver could reflect the damage degree in situ. In this work, we have provided a theoretical design strategy to determine the generation of photo-induced electron transfer mechanism and achieve high selectivity for the target. After that, we precisely synthesized a novel near-infrared fluorescent probe BSR1 to specifically monitor endogenous GSH and hepatotoxicity in biosystem with a moderate fluorescent quantum yield (Φ = 0.394) and low detection limit (83 nM) under this strategy. Moreover, this mapping method for imaging GSH depletion in vivo to assay hepatotoxicity may provide a powerful molecular tool for early diagnosis of some diseases and contribute to assay hepatotoxicity for the development of new drugs. Importantly, this theoretical calculation-guided design strategy may provide an effective way for the precise synthesis of the target-specific fluorescent probe and change this research area from "trial-and-error" to concrete molecular engineering.

A computational model for hepatotoxicity by coupling drug transport and acetaminophen metabolism equations

The spatial distributions of cytochrome P450 (CYP450) and glutathione (GSH) in liver lobules determine the heterogeneous hepatotoxicity of acetaminophen (APAP). Their interplay in conjunction with blood flow is not well understood. In this paper, we integrate a cellular APAP metabolism model with a sinusoidal blood flow to simulate the temporal-spatial patterns of APAP-induced hepatotoxicity. The heterogeneous distribution of CYP450 and GSH is modeled by linearly varying their reaction rates along the portal triad to the central vein axis of a sinusoid. We found that the spatial distribution of GSH, glutathione S-transferases (GSTs), and CYP450 all contributes to the high acetaminophen protein adduct formation at zone 3 of the lobules. The reversed spatial gradients of CYP450 and GSH cause quick depletion of GSH, which is further accelerated by the distribution of GST. The hepatic flow congestion and hyperperfusion however do not seem to play a significant role in the zonal hepatotoxicity. The simulation results may be useful for understanding the APAP-induced hepatotoxicity and associated pharmaceutical treatment.

Evaluation of the hepatoprotective, anti-inflammatory, antinociceptive and antiepileptic activities of Chrysanthemum trifurcatum

Chrysanthemum trifurcatum is common to Mediterranean countries and widely-used in traditional medicine. Due to the scarcity of data about the pharmacological properties of C. trifurcatum, this present study was designed to determine the effects of C. trifurcatumethanolic extract (CEE) for its anti-nociceptive, anti-epileptic, anti-inflammatory, and hepatoprotective activities in mice and rat models. We demonstrate that CEE contains alkaloids, carbohydrates, and flavonoids, and in a dose-dependent (300 and 500 mg/kg) manner exhibited significant reductions in paracetamol (PCM; 500 mg/kg)-induced increased serum AST, ALT and ALP levels, similar to as seen by silymarin (25 mg/kg). Additionally, CEE (300 mg/kg) elicited inhibition in acetic acid-induced abdominal writhes, delayed latency time to paw's licking in hot plate tests, exerted an anti-convulsant effect by prolonging the onset of clonic and tonic convulsions, and reduced pentylenetetrazole (PTZ; 80 mg/kg)-induced mortality. Moreover, CEE (500 mg/kg) exhibited a prominent reduction in carrageenan-induced paw edema. These studies indicate that CEE possesses profound central and peripheral analgesic, anti-convulsant, anti-inflammatory, and hepatoprotective activities.

Liquid Chromatography-Tandem Mass Spectrometry Analysis of Acetaminophen Covalent Binding to Glutathione S-Transferases

Acetaminophen (APAP)-induced hepatotoxicity is the most common cause of acute liver failure in the Western world. APAP is bioactivated to N-acetyl p-benzoquinone imine (NAPQI), a reactive metabolite, which can subsequently covalently bind to glutathione and protein thiols. In this study, we have used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to characterize NAPQI binding to human glutathione S-transferases (GSTs) in vitro. GSTs play a crucial role in the detoxification of reactive metabolites and therefore are interesting target proteins to study in the context of APAP covalent binding. Recombinantly-expressed and purified GSTs were used to assess NAPQI binding in vitro. APAP biotransformation to NAPQI was achieved using rat liver microsomes or human cytochrome P450 Supersomes in the presence of GSTA1, M1, M2, or P1. Resulting adducts were analyzed using bottom-up proteomics, with or without LC fractionation prior to LC-MS/MS analysis on a quadrupole-time-of-flight instrument with data-dependent acquisition (DDA). Targeted methods using multiple reaction monitoring (MRM) on a triple quadrupole platform were also developed by quantitatively labeling all available cysteine residues with a labeling reagent yielding isomerically-modified peptides following enzymatic digestion. Seven modified cysteine sites were confirmed, including Cys112 in GSTA1, Cys78 in GSTM1, Cys115 and 174 in GSTM2, as well as Cys15, 48, and 170 in GSTP1. Most modified peptides could be detected using both untargeted (DDA) and targeted (MRM) approaches, however the latter yielded better detection sensitivity with higher signal-to-noise and two sites were uniquely found by MRM.

Hepatic Bioactivation of Skin-Sensitizing Drugs to Immunogenic Reactive Metabolites

The clinical use of some drugs, such as carbamazepine, phenytoin, and allopurinol, is often associated with adverse cutaneous reactions. The bioactivation of drugs into immunologically reactive metabolites by the liver is postulated to be the first step in initiating a downstream cascade of pathological immune responses. Current mechanistic understanding and the ability to predict such adverse drug cutaneous responses have been partly limited by the lack of appropriate cutaneous drug bioactivation experimental models. Although in vitro human liver models have been extensively investigated for predicting hepatotoxicity and drug-drug interactions, their ability to model the generation of antigenic reactive drug metabolites that are capable of eliciting immunological reactions is not well understood. Here, we employed a human progenitor cell (HepaRG)-derived hepatocyte model and established highly sensitive liquid chromatography-mass spectrometry analytical assays to generate and quantify different reactive metabolite species of three paradigm skin sensitizers, namely, carbamazepine, phenytoin, and allopurinol. We found that the generation of reactive drug metabolites by the HepaRG-hepatocytes was sensitive to the medium composition. In addition, a functional assay based on the activation of U937 myeloid cells into the antigen-presenting cell (APC) phenotype was established to evaluate the immunogenicity potential of the reactive drug metabolites produced by HepaRG-derived hepatocytes. We showed that the reactive drug metabolites of known skin sensitizers could significantly upregulate IL8, IL1β, and CD86 expressions in U937 cells compared to the metabolites from a nonskin sensitizer (i.e., acetaminophen). Thus, the extent of APC activation by HepaRG-hepatocytes conditioned medium containing reactive drug metabolites can potentially be used to predict their skin sensitization potential.

Epigallocatechin-3-Gallate Reduces Hepatic Oxidative Stress and Lowers CYP-Mediated Bioactivation and Toxicity of Acetaminophen in Rats

Epigallocatechin-3-gallate (EGCG) is the most abundant polyphenol in green tea. To investigate the effects of dietary EGCG on oxidative stress and the metabolism and toxicity of acetaminophen in the liver, rats were fed diets with (0.54%) or without EGCG supplementation for four weeks and were then injected intraperitoneally with acetaminophen (1 g/kg). The results showed that EGCG lowered hepatic oxidative stress and cytochrome P450 (CYP) 1A2, 2E1, and 3A, and UDP-glucurosyltransferase activities prior to acetaminophen injection. After acetaminophen challenge, the elevations in plasma alanine aminotransferase activity and histological changes in the liver were ameliorated by EGCG treatment. EGCG reduced acetaminophen-induced apoptosis by lowering the Bax/Bcl2 ratio in the liver. EGCG mildly increased autophagy by increasing the LC3B II/I ratio. Lower hepatic acetaminophen–glutathione and acetaminophen–protein adducts contents were observed after EGCG treatment. EGCG increased glutathione peroxidase and NAD(P)H quinone 1 oxidoreductase activities and reduced organic anion-transporting polypeptides 1a1 expression in the liver after acetaminophen treatment. Our results indicate that EGCG may reduce oxidative stress and lower the metabolism and toxicity of acetaminophen. The reductions in CYP-mediated acetaminophen bioactivation and uptake transporter, as well as enhanced antioxidant enzyme activity, may limit the accumulation of toxic products in the liver and thus lower hepatotoxicity.

A Review of Bioinformatics Tools to Understand Acetaminophen-Alcohol Interaction

Background: Drug-ethanol interaction can result in hepatotoxicity. The liver is capable of metabolizing both acetaminophen and ethanol; however, severe acute or moderate chronic simultaneous exposure can cause cell and tissue damage. Therapeutic doses can become harmful if gene activity is altered via competition for metabolic pathways. Simultaneous intake of ethanol and acetaminophen results in overactive CYP2E1 and depletion of glutathione, leaving NAPQI to build up in the liver. NAPQI is a hepatotoxic substance typically neutralized by glutathione. Methods: Bioinformatics tools including PharmGKB, Chemical Annotation Retrieval Toolkit, Transcriptome Analysis Console 4.0 (TAC), wikipathways, STRING, and Ingenuity Pathway Analysis (IPA) were used to explore interactive metabolic pathways of ethanol-acetaminophen exposure as a proof of concept for assessing drug-drug or drug-alcohol interactions. Results: As the ethanol-acetaminophen comparison indicates, bioinformatics tools may be used to understand interactive pathways following exposure to ethanol and acetaminophen, with potential extrapolation to other drug-drug/drug-ethanol interactions. Conclusions: Direct interactive effects were not able to be confirmed through this bioinformatics study due to the lack of existing ethanol-acetaminophen simultaneous exposure data. This work suggests that a battery of software applications should be used to assess interactive effects.

Intake of Molecular Hydrogen in Drinking Water Increases Membrane Transporters, p-Glycoprotein, and Multidrug Resistance-Associated Protein 2 without Affecting Xenobiotic-Metabolizing Enzymes in Rat Liver

Molecular hydrogen (H2) has been shown to have antioxidant and anti-inflammatory activities that may reduce the development and progression of many diseases. In this study, hydrogen-rich water (HRW) was obtained by reacting hybrid magnesium-carbon hydrogen storage materials with water. Then, the effects of intake of HRW on the activities of xenobiotic-metabolizing enzymes, membrane transporters, and oxidative stress in rats were investigated. Rats were given HRW ad libitum for four weeks. The results showed that intake of HRW had no significant effect on the activities of various cytochrome P450 (CYP) enzymes (CYP1A1, 1A2, 2B, 2C, 2D, 2E1, 3A, and 4A), glutathione-S-transferase, and Uridine 5'-diphospho (UDP)-glucuronosyltransferase. Except for a mild lower plasma glucose concentration, intake of HRW had no effect on other plasma biochemical parameters in rats. p-Glycoprotein and multidrug resistance-associated protein (Mrp) 2 protein expressions in liver were elevated after intake of HRW. However, HRW had no significant effects on glutathione, glutathione peroxidase, or lipid peroxidation in liver. The results from this study suggest that consumption of HRW may not affect xenobiotic metabolism or oxidative stress in liver. However, intake of HRW may increase the efflux of xenobiotics or toxic substances from the liver into bile by enhancing p-glycoprotein and Mrp2 protein expressions.

Hyperglycemia exacerbates acetaminophen-induced acute liver injury by promoting liver-resident macrophage proinflammatory response via AMPK/PI3K/AKT-mediated oxidative stress

Although diabetes mellitus/hyperglycemia is a risk factor for acute liver injury, the underlying mechanism remains largely unknown. Liver-resident macrophages (Kupffer cells, KCs) and oxidative stress play critical roles in the pathogenesis of toxin-induced liver injury. Here, we evaluated the role of oxidative stress in regulating KC polarization against acetaminophen (APAP)-mediated acute liver injury in a streptozotocin-induced hyperglycemic murine model. Compared to the controls, hyperglycemic mice exhibited a significant increase in liver injury and intrahepatic inflammation. KCs obtained from hyperglycemic mice secreted higher levels of the proinflammatory factors, such as TNF-α and IL-6, lower levels of the anti-inflammatory factor IL-10. Furthermore, enhanced oxidative stress was revealed by increased levels of reactive oxygen species (ROS) in KCs from hyperglycemic mice post APAP treatment. In addition, ROS inhibitor NAC resulted in a significant decrease of ROS production in hyperglycemic KCs from mice posttreated with APAP. We also analyzed the role of hyperglycemia in macrophage M1/M2 polarization. Interestingly, we found that hyperglycemia promoted M1 polarization, but inhibited M2 polarization of KCs obtained from APAP-exposed livers, as evidenced by increased MCP-1 and inducible NO synthase (iNOS) gene induction but decreased Arg-1 and CD206 gene induction accompanied by increased STAT1 activation and decreased STAT6 activation. NAC restored Arg-1, CD206 gene induction, and STAT6 activation. To explore the mechanism how hyperglycemia regulates KCs polarization against APAP-induced acute liver injury, we examined the AMPK/PI3K/AKT signaling pathway and found decreased AMPK activation and increased AKT activation in liver and KCs from hyperglycemic mice post APAP treatment. AMPK activation by its agonist AICAR or PI3K inhibition by its antagonist LY294002 inhibited ROS production in KCs from hyperglycemic mice post APAP treatment and significantly attenuated APAP-induced liver injury in the hyperglycemic mice, compared to the control mice. Our results demonstrated that hyperglycemia exacerbated APAP-induced acute liver injury by promoting liver-resident macrophage proinflammatory response via AMPK/PI3K/AKT-mediated oxidative stress.

Inactivation of Sirtuin2 protects mice from acetaminophen-induced liver injury: possible involvement of ER stress and S6K1 activation

Acetaminophen (APAP) overdose can cause hepatotoxicity by inducing mitochondrial damage and subsequent necrosis in hepatocytes. Sirtuin2 (Sirt2) is an NAD⁺-dependent deacetylase that regulates several biological processes, including hepatic gluconeogenesis, as well as inflammatory pathways. We show that APAP decreases the expression of Sirt2. Moreover, the ablation of Sirt2 attenuates APAP-induced liver injuries, such as oxidative stress and mitochondrial damage in hepatocytes. We found that Sirt2 deficiency alleviates the APAP-mediated endoplasmic reticulum (ER) stress and phosphorylation of the p70 ribosomal S6 kinase 1 (S6K1). Moreover, Sirt2 interacts with and deacetylates S6K1, followed by S6K1 phosphorylation induction. This study elucidates the molecular mechanisms underlying the protective role of Sirt2 inactivation in APAP-induced liver injuries.

Oxidative Stress Parameters after Abdominal Hysterectomy and Their Relationships with Quality of Recovery

Study aimed to investigate relationship between oxidative stress markers and postoperative recovery in woman after abdominal hysterectomy, as well as to test the hypothesis that different analgesics differently influence redox status.

The quality of recovery was evaluated with a QoR-40 questionnaire in fifty-one patients who underwent abdominal hysterectomy, preoperatively and on the 1st, 2nd, 3rd postoperative days (POD1,2,3). Blood samples were collected at baseline (T0), 3 (T1), 24 (T2), 48 (T3) and 72 (T4) hours after surgery. Oxidative stress markers concentrations (TBARS, NO2 −, H2O2, O2 − ) as well as antioxidative enzymes (SOD, CAT, and GSH) were analyzed.

QoR-40 total score significantly declined on POD1 and POD2 and returned to baseline levels on POD3 (p<0.001). H2O2 levels significantly decreased from T0 to T3 and then, increased at T4 (p=0,011). Changes of TBARS and H2O2 from T0 to T3 showed significant and negative correlation (r=−0.303, p=0.046). There was no significant correlation between QoR-40 total score and any parameter of oxidative stress response (p>0.05). Changes in TBARS levels from T0 to T3 were statistically significant between the study subgroups primarily due to increase of the concentrations in patients receiving paracetamol (p=0.031). Patients age, duration of surgery and cigarette smoking status showed significant influcences on and association with some oxidative stress response markers (TBARS, O2 −, CAT) (p<0.05).

Women who underwent hysterectomy had significant changes of H2O2 and TBARS activity however, those changes were not associated with changes of QoR-40 total scores during recovery.

Pharmacokinetic changes of tramadol in rats with hepatotoxicity induced by ethanol and acetaminophen in perfused rat liver model

Tramadol is an opioid agonist with activation monoaminergic properties. It can be administered orally, rectally, intravenously, or intramuscularly as a centrally acting analgesic. Liver injury can lead to changes in the metabolism of tramadol. In this study, the rate of tramadol metabolism in rats with damaged liver induced by ethanol and acetaminophen was assessed in a recirculation perfusion system. Acetaminophen is a mild analgesic and antipyretic agent, which can cause centrilobular hepatic necrosis in toxic doses, whereas alcohol causes death due to liver diseases. Alcoholic liver disease (ALD), such as alcoholic fatty liver, alcoholic hepatitis, and alcoholic fibrosis, is the most common liver disease. The aim of this study was to investigate the alteration in tramadol metabolism in different hepatotoxicity conditions in animal models. Male rats were randomly assigned to three groups. The control group received normal saline, group 2 received acetaminophen at the dose of 250 mg/kg/day, and group 3 received ethanol at the beginning dose of 3 g/kg/day, which was slowly increased to 6 g/kg/day. Tramadol was added to the perfusion solution at the concentration of 500 ng/mL. Samples were collected during 180 min, and analyte concentrations were determined by the High-Performance Liquid Chromatography (HPLC) method. The concentration of tramadol and its three main metabolites, O-desmethyltramadol (M1), N-desmethyltramadol (M2), and N,O-didesmethyltramadol (M5), were determined in perfusate samples. Ethanol and acetaminophen significantly affected the pattern of weight gain and liver weights before perfusion and caused a significant increase in enzyme activities. Moreover, histopathologic examination revealed that ethanol and acetaminophen caused liver damage. An increase in the elimination half-life and reduced clearance rate of tramadol were seen in the acetaminophen and ethanol groups, in comparison to the control group. Additionally, significant reductions in the Area Under the Curve (AUC) of metabolites of tramadol (M1, M2, and M5) were observed in the acetaminophen and ethanol groups in the perfused rat liver model. Liver damage caused by ethanol and acetaminophen during 45 days in animals leads to a significant reduction in the level of tramadol metabolites. Therefore, in patients with liver damage caused by ethanol and acetaminophen, caution needs to be considered when prescribing tramadol.

Hepatoprotective Actions of Ascorbic Acid, Alpha Lipoic Acid and Silymarin or Their Combination Against Acetaminophen-Induced Hepatotoxicity in Rats

Background and objectives: Ascorbic acid, alpha lipoic acid (ALA) and silymarin are well-known antioxidants that have hepatoprotective effects. This study aims to investigate the effects of these three compounds combined with attenuating drug-induced oxidative stress and cellular damage, taking acetaminophen (APAP)-induced toxicity in rats as a model both in vivo and in vitro. Materials and Methods: Freshly cultured primary rat hepatocytes were treated with ascorbic acid, ALA, silymarin and their combination, both with and without the addition of APAP to evaluate their in vitro impact on cell proliferation and mitochondrial activity. In vivo study was performed on rats supplemented with the test compounds or their combination for one week followed by two toxic doses of APAP. Results: Selected liver function tests and oxidative stress markers including superoxide dismutase (SOD), malondialdehyde (MDA) and oxidized glutathione (GSSG) were detected. The in vivo results showed that all three pretreatment compounds and their combination prevented elevation of SOD and GSSG serum levels indicating a diminished burden of oxidative stress. Moreover, ascorbic acid, ALA and silymarin in combination reduced serum levels of liver enzymes; however, silymarin markedly maintained levels of all parameters to normal ranges. Silymarin either alone or combined with ascorbic acid and ALA protected cultured rat hepatocytes and increased cellular metabolic activity. The subjected agents were capable of significantly inhibiting the presence of oxidative stress induced by APAP toxicity and the best result for protection was seen with the use of silymarin. Conclusions: The measured liver function tests may suggest an augmented hepatoprotection of the combination preparation than when compared individually.

Salvianolic Acid C against Acetaminophen-Induced Acute Liver Injury by Attenuating Inflammation, Oxidative Stress, and Apoptosis through Inhibition of the Keap1/Nrf2/HO-1 Signaling

Acetaminophen (APAP) overdose is one of the most common causes of drug-induced acute liver failure in humans. To investigate the hepatoprotective effect of salvianolic acid C (SAC) on APAP-induced hepatic damage, SAC was administered by daily intraperitoneal (i.p.) injection for 6 days before the APAP administration in mice. SAC prevented the elevation of serum biochemical parameters and lipid profile including aspartate aminotransferase (AST), alanine aminotransferase (ALT), total bilirubin (T-Bil), total cholesterol (TC), and triacylglycerol (TG) against acute liver failure. Additionally, SAC reduced the content of malondialdehyde (MDA), the cytochrome P450 2E1 (CYP2E1), and the histopathological alterations and inhibited the production of proinflammatory cytokines in APAP-induced hepatotoxicity. Importantly, SAC effectively diminished APAP-induced liver injury by inhibiting nuclear factor-kappa B (NF-κB), toll-like receptor 4 (TLR4), and mitogen-activated protein kinases (MAPKs) activation signaling pathway. Moreover, SAC enhanced the levels of hepatic activities of glutathione (GSH), superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, and Kelch-like ECH-associated protein 1 (Keap1)/erythroid 2–related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) pathway in APAP-induced mice. SAC mainly inhibited the activation of apoptotic pathways by reduction of cytochrome c, Bax, and caspase-3 protein expression. Taken together, we provide the molecular evidence that SAC protected the hepatocytes from APAP-induced damage by mitigating mitochondrial oxidative stress, inflammatory response, and caspase-mediated antiapoptotic effect through inhibition of the Keap1/Nrf2/HO-1 signaling axis.

Exposure to acetaminophen impairs vasodilation, increases oxidative stress and changes arterial morphology of rats

Acetaminophen (APAP) is one of the most widely consumed drugs in the world. Studies have shown renal and hepatic damage as the direct result of high oxidative stress induced by APAP. Since the cardiovascular system is sensitive to oxidative stress and literature describes increased cardiovascular dysfunction in APAP consumers, this work aimed to evaluate harmful effects of APAP on the vascular system. Rats were exposed to APAP (400 mg/kg/day in drinking water) for 14 days. Plasma and aortas were collected and stored in - 80 °C and a selection of arteries was prepared for isometric tension recordings, morphological, immunohistochemical and protein expression analysis. The APAP-treated group presented increased transaminases (ALT/AST) and malondialdehyde levels in the plasma compared to controls. Lipid peroxidation, glutathione reductase and superoxide dismutase levels were increased in the plasma and arteries of the APAP group. Nevertheless, glutathione level was reduced as compared to control group. The vasodilation response to acetylcholine and sodium nitroprusside (0.1 nM to 10 µM) was also impaired after APAP treatment; however, the vascular relaxation was restored after treatment with vitamin C (100 µM). Arteries from the APAP group presented reduced wall thickness, collagen deposition, elastic fibers and increased immunoreactivity to nitrotyrosine. eNOS and sGC protein expression remained unchanged and were at similar levels as controls. These findings showed higher oxidative stress and impaired vasodilation in rats exposed to APAP. Furthermore, arteries presented reduced cell layers, collagen, elastin deposition and significantly increased immunoreactivity to nitrotyrosine after APAP treatment.

Research Progress on the Animal Models of Drug-Induced Liver Injury: Current Status and Further Perspectives

Drug-induced liver injury (DILI) is a major concern in clinical studies as well as in postmarketing surveillance. It is necessary to establish an animal model of DILI for thorough investigation of mechanisms of DILI and searching for protective medications. This article reviews the current status and future perspective on establishment of DILI models based on different hepatotoxic drugs, as well as the underlying mechanisms of liver function damage induced by specific medicine. Therefore, information from this article can help researchers make a suitable selection of animal models for further study.

Mechanistic identification of biofluid metabolite changes as markers of acetaminophen-induced liver toxicity in rats

Acetaminophen (APAP) is the most commonly used analgesic and antipyretic drug in the world. Yet, it poses a major risk of liver injury when taken in excess of the therapeutic dose. Current clinical markers do not detect the early onset of liver injury associated with excess APAP-information that is vital to reverse injury progression through available therapeutic interventions. Hence, several studies have used transcriptomics, proteomics, and metabolomics technologies, both independently and in combination, in an attempt to discover potential early markers of liver injury. However, the casual relationship between these observations and their relation to the APAP mechanism of liver toxicity are not clearly understood. Here, we used Sprague-Dawley rats orally gavaged with a single dose of 2 g/kg of APAP to collect tissue samples from the liver and kidney for transcriptomic analysis and plasma and urine samples for metabolomic analysis. We developed and used a multi-tissue, metabolism-based modeling approach to integrate these data, characterize the effect of excess APAP levels on liver metabolism, and identify a panel of plasma and urine metabolites that are associated with APAP-induced liver toxicity. Our analyses, which indicated that pathways involved in nucleotide-, lipid-, and amino acid-related metabolism in the liver were most strongly affected within 10 h following APAP treatment, identified a list of potential metabolites in these pathways that could serve as plausible markers of APAP-induced liver injury. Our approach identifies toxicant-induced changes in endogenous metabolism, is applicable to other toxicants based on transcriptomic data, and provides a mechanistic framework for interpreting metabolite alterations.

Abnormal Liver Enzymes

Abnormal liver enzymes are frequently encountered in primary care offices and hospitals and may be caused by a wide variety of conditions, from mild and nonspecific to well-defined and life-threatening. Terms such as "abnormal liver chemistries" or "abnormal liver enzymes," also referred to as transaminitis, should be reserved to describe inflammatory processes characterized by elevated alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase. Although interchangeably used with abnormal liver enzymes, abnormal liver function tests specifically denote a loss of synthetic functions usually evaluated by serum albumin and prothrombin time. We discuss the entities that most commonly cause abnormal liver enzymes, specific patterns of enzyme abnormalities, diagnostic modalities, and the clinical scenarios that warrant referral to a hepatologist.

Improving Drug Discovery by Nucleic Acid Delivery in Engineered Human Microlivers

The liver plays a central role in metabolism; however, xenobiotic metabolism variations between human hepatocytes and those in model organisms create challenges in establishing functional test beds to detect the potential drug toxicity and efficacy of candidate small molecules. In the emerging areas of RNA interference, viral gene therapy, and genome editing, more robust, long-lasting, and predictive human liver models may accelerate progress. Here, we apply a new modality to a previously established, functionally stable, multi-well bioengineered microliver-fabricated from primary human hepatocytes and supportive stromal cells-in order to advance both small molecule and nucleic acid therapeutic pipelines. Specifically, we achieve robust and durable gene silencing in vitro to tune the human metabolism of small molecules, and demonstrate its capacity to query the potential efficacy and/or toxicity of candidate therapeutics. Additionally, we apply this engineered platform to test siRNAs designed to target hepatocytes and impact human liver genetic and infectious diseases.

Factors associated with self-medication in users of drugstores and pharmacies in Peru: an analysis of the National Survey on User Satisfaction of Health Services, ENSUSALUD 2015

Background: Irresponsible self-medication is a problem for health systems in developing countries. We aimed to estimate the frequency of self-medication and associated factors in users of drugstores and pharmacies in Peru.

Methods: We performed a secondary data analysis of the 2015 National Survey on User Satisfaction of Health Services (ENSUSALUD), a two-stage probabilistic sample of all regions of Peru. Non self-medication (NSM), responsible self-medication (RSM) and irresponsible self-medication (ISM) were defined as the outcome categories. Demographic, social, cultural and health system variables were included as covariates. We calculated relative prevalence ratios (RPR) with their 95% confidence intervals (95%CI) using crude and adjusted multinomial logistic regression models for complex samples with NSM as the referent category.

Results: 2582 participants were included. The average age was 41.4 years and the frequencies of NSM, RSM and ISM were 25.2%, 23.8% and 51.0%; respectively. The factors associated with RSM were male gender (RPR: 1.35; 95%CI: 1.06-1.72), being between 40 and 59 years old (RPR: 0.53; 95%IC: 0.39-0.72), being 60 or older (RPR: 0.39; 95%IC: 0.25-0.59), not having health insurance (RPR: 1.89; 95%CI: 1.31-2.71) and living in the Highlands region (RPR: 2.27; 95%CI: 1.23-4.21). The factors associated with ISM were male gender (RPR: 1.41; 95%CI: 1.16-1.72), being between 40 and 59 years old (RPR: 0.68; 95%IC: 0.53-0.88), being 60 or older (RPR: 0.65; 95%IC: 0.48-0.88) and not having health insurance (RPR: 2.03; 95%CI: 1.46-2.83).

Conclusion: Around half of the population practiced ISM, which was associated with demographic and health system factors. These outcomes are the preliminary evidence that could contribute to the development of health policies in Peru.

Factors associated with self-medication in users of drugstores and pharmacies in Peru: an analysis of the National Survey on User Satisfaction of Health Services, ENSUSALUD 2015

Background: Irresponsible self-medication is a problem for health systems in developing countries. We aimed to estimate the frequency of self-medication and associated factors in users of drugstores and pharmacies in Peru. Methods: We performed a secondary data analysis of the 2015 National Survey on User Satisfaction of Health Services (ENSUSALUD), a two-stage probabilistic sample of all regions of Peru. Non self-medication (NSM), responsible self-medication (RSM) and irresponsible self-medication (ISM) were defined as the outcome categories. Demographic, social, cultural and health system variables were included as covariates. We calculated relative prevalence ratios (RPR) with their 95% confidence intervals (95%CI) using crude and adjusted multinomial logistic regression models for complex samples with NSM as the referent category. Results: 2582 participants were included. The average age was 41.4 years and the frequencies of NSM, RSM and ISM were 25.2%, 23.8% and 51.0%; respectively. The factors associated with RSM were male gender (RPR: 1.35; 95%CI: 1.06-1.72), being between 40 and 59 years old (RPR: 0.53; 95%IC: 0.39-0.72), being 60 or older (RPR: 0.39; 95%IC: 0.25-0.59), not having health insurance (RPR: 1.89; 95%CI: 1.31-2.71) and living in the Highlands region (RPR: 2.27; 95%CI: 1.23-4.21). The factors associated with ISM were male gender (RPR: 1.41; 95%CI: 1.16-1.72), being between 40 and 59 years old (RPR: 0.68; 95%IC: 0.53-0.88), being 60 or older (RPR: 0.65; 95%IC: 0.48-0.88) and not having health insurance (RPR: 2.03; 95%CI: 1.46-2.83). Conclusion: Around half of the population practiced ISM, which was associated with demographic and health system factors. These outcomes are the preliminary evidence that could contribute to the development of health policies in Peru.

Transformation of acetaminophen in natural surface water and the change of aquatic microbes

The kinetics and transformation pathway of acetaminophen (APAP) in natural surface water (one sample from the Yangtze River and three others from different lakes), and the changes of aquatic microbes in surface water were revealed in this study. Both photochemical and microbial reactions contributed to the transformation of APAP under irradiance of 1.0-250 mW/cm². Microbial compositions were significantly different among surface water, and same microbial transformation product (1,4-bezoquinone) was detected as the predominant biotransformation intermediate in four studied surface water, but the lag phase (12-50-h) for the transformation was highly dependent on the aquatic microbial abundance and composition. The lag phase no longer existed with irradiance increased to 5.9 mW/cm². Aquatic microbial abundance and composition were influenced by the presence of APAP and radiation, and the influence extent was dependent on microbial species. The findings demonstrated that the individual contribution of biotic and abiotic process to the overall transformation of APAP and maybe other phenol in surface water varied as the background composition of surface water and the external environment changed, and biotransformation dominated (>73%) the overall transformation of APAP in surface water.