Oxidative stress during acetaminophen hepatotoxicity: Sources, pathophysiological role and therapeutic potential. Redox Biol. 2016;10:148-156. [PMID: 27744120 PMCID: PMC5065645 DOI: 10.1016/j.redox.2016.10.001]

Multienzyme-like active MnO2 nanozyme with ROS scavenging for inflammatory injury therapy induced by avian flavivirus through antiviral function

Duck Tembusu virus (DTMUV) is an acute avian flavivirus that primarily infects poultry, mosquitoes, and some mammals including humans. The viral infection triggers reactive oxygen species (ROS) and inflammatory response that are crucial in mediating injury. Crafting multifunctional nanozymes that possess both ROS scavenging and anti-inflammatory activities presents formidable challenges. The study synthesized manganese dioxide cauliflowers (MnO2 Cfs) endowed with multiple enzyme-like activities (analogous to SOD, CAT, and GPX) that effectively alleviated the injury induced by DTMUV both in vitro and in vivo. Remarkably, MnO2 Cfs efficiently neutralized various ROS, encompassing hydrogen peroxide (H2O2), superoxide anion (O2·-) and hydroxyl radical (·OH). Our in vitro assessments showed that MnO2 Cfs could alleviate cytopathic effects and modulate the innate immune response during DTMUV infection through their ROS scavenging and anti-inflammatory properties. In vivo experiments supported these findings, demonstrating that ducklings therapied by MnO2 Cfs experienced alleviated injury during DTMUV infection. Importantly, MnO2 Cfs also effectively inhibited DTMUV replication in both laboratory and field conditions. This study presents a novel strategy for nanozyme design, promising significant therapeutic potential for treating viral inflammatory diseases.

Metabolic reprogramming of corn oligopeptide in regulating sodium nitrite-induced canine hepatocyte injury via TGF/NF-κB signaling pathways and aminoacyl-tRNA biosynthesis

Sodium nitrite (SN), a prevalent food preservative, is known to precipitate hepatotoxicity upon exposure. This study elucidates the hepatoprotective effects of corn oligopeptide (COP) and vitamin E (VE) against SN-induced hepatic injury in canine hepatocytes. Canine liver cells were subjected to SN to induce hepatotoxicity, followed by treatment with COP and VE. Evaluations included assays for cell viability, oxidative stress markers, apoptosis, and inflammatory cytokines. Additionally, transcriptomic and metabolomic analyses were performed to delineate the underlying molecular mechanisms. The findings demonstrated that COP and VE significantly ameliorated SN-induced cytotoxicity, oxidative stress, and apoptosis. It was evidenced by restored cell viability, enhanced antioxidant enzyme activity, reduced cytoplasmic enzyme leakage, and decreased levels of malondialdehyde and inflammatory cytokines, with COP showing superior efficacy. The RNA sequencing revealed that COP treatment suppressed the SN-activated aminoacyl-tRNA biosynthesis pathway and TGF-β/NF-κB signaling pathways, thereby mitigating amino acid depletion, apoptosis, and inflammation. Moreover, COP treatment upregulated genes associated with protein folding, bile acid synthesis, and DNA repair. Metabolomic analysis corroborated these results, showing that COP restored amino acid levels and enhanced bile acid metabolism, alleviating SN-induced metabolic disruptions. These findings offered significant insights into the protective mechanisms of COP underscoring its prospective application in treating liver injuries.

Oral administration of astilbin mitigates acetaminophen-induced acute liver injury in mice by modulating the gut microbiota

Acetaminophen (APAP) overdose-induced acute liver injury (ALI) is characterized by extensive oxidative stress, and the clinical interventions for this adverse effect remain limited. Astilbin is an active compound found in the rhizome of Smilax glabra Roxb. with anti-inflammatory and antioxidant activities. Due to its low oral bioavailability, astilbin can accumulate in the intestine, which provides a basis for the interaction between astilbin and gut microbiota (GM). In the present study we investigated the protective effects of astilbin against APAP-induced ALI by focusing on the interaction between astilbin and GM. Mice were treated with astilbin (50 mg·kg-1·d-1, i.g.) for 7 days. After the last administration of astilbin for 2 h, the mice received APAP (300 mg/kg, i.g.) to induce ALI. We showed that oral administration of astilbin significantly alleviated APAP-induced ALI by altering the composition of GM and enriching beneficial metabolites including hydroxytyrosol (HT). GM depletion using an "antibiotics cocktail" or paraoral administration of astilbin abolished the hepatoprotective effects of astilbin. On the other hand, administration of HT (10 mg/kg, i.g.) caused similar protective effects in APAP-induced ALI mice. Transcriptomic analysis of the liver tissue revealed that HT inhibited reactive oxygen species and inflammation-related signaling in APAP-induced ALI; HT promoted activation of the Nrf2 signaling pathway to combat oxidative stress following APAP challenge in a sirtuin-6-dependent manner. These results highlight that oral astilbin ameliorates APAP-induced ALI by manipulating the GM and metabolites towards a more favorable profile, and provide an alternative therapeutic strategy for alleviating APAP-induced ALI.

Theoretical insights into a turn-on fluorescence probe based on naphthalimide for peroxynitrite detection

Compared with other reactive oxygen species, peroxynitrite (ONOO-) has diversified reactions and transformations in organisms, and its specific action mechanism is not very clear. The study of reactive oxygen species is of great significance in the field of physiology and pathology. Recently an effective on/off fluorescent probe HCA-OH was designed by Liu et al. through tethering p-aminophenol to 1,8-naphthalimide directly. The probe HCA-OH could release the fluorophore HCA-NH2 with good photostability and high fluorescence quantum yield under oxidation of ONOO- via dearylation process. In this work, the sensing mechanism and spectrum character of probe HCA-OH were studied in detail under quantum chemistry calculation. The electronic structures, reaction sites and fluorescent properties of the probe were theoretically analyzed to benefit us for in-depth understanding the principle of detection on reactive oxygen species (ONOO-) with the fluorescent probe HCA-OH. These theoretical results could inspire the medical research community to design and synthesize highly efficient fluorescent probe for reactive oxygen species detection.

Drug-induced oxidative stress actively prevents caspase activation and hepatocyte apoptosis

Cell death is a fundamental process in health and disease. Emerging research shows the existence of numerous distinct cell death modalities with similar and intertwined signaling pathways, but resulting in different cellular outcomes, raising the need to understand the decision-making steps during cell death signaling. Paracetamol (Acetaminophen, APAP)-induced hepatocyte death includes several apoptotic processes but eventually is executed by oncotic necrosis without any caspase activation. Here, we studied this paradoxical form of cell death and revealed that APAP not only fails to activate caspases but also strongly impedes their activation upon classical apoptosis induction, thereby shifting apoptosis to necrosis. While APAP intoxication results in massive drop in mitochondrial respiration, low cellular ATP levels could be excluded as an underlying cause of missing apoptosome formation and caspase activation. In contrast, we identified oxidative stress as a key factor in APAP-induced caspase inhibition. Importantly, caspase inhibition and the associated switch from apoptotic to necrotic cell death was reversible through the administration of antioxidants. Thus, exemplified by APAP-induced cell death, our study stresses that cellular redox status is a critical component in the decision-making between apoptotic and necrotic cell death, as it directly affects caspase activity.

Phytochemical Analysis, and Antioxidant and Hepatoprotective Activities of Chamaerops humilis L. Leaves; A Focus on Xanthine Oxidase

Chamaerops humilis L. is clumping palm of the family Arecaceae with promising health-promoting effects. Parts of this species are utilized as food and employed in folk medicine to treat several disorders. This study investigated the phytochemical constituents of C. humilis leaves and their antioxidant and xanthine oxidase (XO) inhibitory activities in vitro and in vivo in acetaminophen (APAP)-induced hepatotoxicity in rats. The chemical structure of the isolated phytochemicals was determined using data obtained from UV, MS, IR, and 1H-, 13C-NMR spectroscopic tools as well as comparison with authentic markers. Eleven compounds, including tricin 7-O-β-rutinoside, vicenin, tricin, astragalin, borassoside D, pregnane-3,5,6,16-tetrol, oleanolic acid, β-sitosterol and campesterol were isolated from C. humilis ethanolic extract (CHEE). CHEE and the butanol, n-hexane, and dichloromethane fractions exhibited in vitro radical scavenging and XO inhibitory efficacies. The computational findings revealed the tendency of the isolated compounds towards the active site of XO. In vivo, CHEE ameliorated liver function markers and prevented tissue injury induced by APAP in rats. CHEE suppressed hepatic XO, decreased serum uric acid and liver malondialdehyde (MDA), and enhanced reduced glutathione (GSH), superoxide dismutase (SOD), and catalase in APAP-treated rats. CHEE ameliorated serum tumor necrosis factor alpha (TNF-α) and interleukin (IL)-1β in APAP-treated rats. Thus, C. humilis is rich in beneficial phytochemicals that possess binding affinity towards XO. C. humilis exhibited potent in vitro antioxidant and XO inhibitory activities, and prevented APAP hepatotoxicity by attenuating tissue injury, oxidative stress and inflammation.

Novel reduced heteropolyacid nanoparticles for effective treatment of drug-induced liver injury by manipulating reactive oxygen and nitrogen species and inflammatory signals

With the rapid advancements in biomedicine, the use of clinical drugs has surged sharply. However, potential hepatotoxicity limits drug exploitation and widespread usage, posing serious threats to patient health. Hepatotoxic drugs disrupt liver enzyme levels and cause refractory pathological damage, creating a challenge in the application of diverse first-line drugs. The activation and deterioration of reactive oxygen and nitrogen species (RONS) and inflammatory signals are key pathological mechanisms of drug-induced liver injury (DILI). Herein, a novel reduced heteropolyacid nanoparticle (RNP) has been developed, possessing high RONS-scavenging ability, strong anti-inflammatory activity, and excellent biosafety. These features enable it to swiftly restore the redox and immune balance of the liver. Intravenous administration of RNP effectively scavenged RONS storm, reversing liver oxidative stress and restoring normal mitochondrial membrane potential and function. Furthermore, by inhibiting c-Jun-N-terminal kinase phosphorylation, RNP facilitated the restoration of nuclear factor erythroid 2-related factor 2-mediated endogenous antioxidant signaling, ultimately rescuing the liver function and tissue morphology in acetaminophen-induced DILI mice. Crucially, the high biocompatible RNP exhibited superior efficacy in the DILI mouse model compared to the clinical antioxidant N-acetylcysteine. This targeted therapeutic approach, tailored to address the onset and progression of DILI, offers valuable new insights into controlling the condition and restoring liver structure and function.

Sirtuin 5-Mediated Desuccinylation of ALDH2 Alleviates Mitochondrial Oxidative Stress Following Acetaminophen-Induced Acute Liver Injury

Acetaminophen (APAP) overdose is a major cause of drug-induced liver injury. Sirtuins 5 (SIRT5) has been implicated in the development of various liver diseases. However, its involvement in APAP-induced acute liver injury (AILI) remains unclear. The present study aimed to explore the role of SIRT5 in AILI. SIRT5 expression is dramatically downregulated by APAP administration in mouse livers and AML12 hepatocytes. SIRT5 deficiency not only exacerbates liver injury and the inflammatory response, but also worsens mitochondrial oxidative stress. Conversely, the opposite pathological and biochemical changes are observed in mice with SIRT5 overexpression. Mechanistically, quantitative succinylome analysis and site mutation experiments revealed that SIRT5 desuccinylated aldehyde dehydrogenase 2 (ALDH2) at lysine 385 and maintained the enzymatic activity of ALDH2, resulting in the suppression of inflammation and mitochondrial oxidative stress. Furthermore, succinylation of ALDH2 at lysine 385 abolished its protective effect against AILI, and the protective effect of SIRT5 against AILI is dependent on the desuccinylation of ALDH2 at K385. Finally, virtual screening of natural compounds revealed that Puerarin promoted SIRT5 desuccinylase activity and further attenuated AILI. Collectively, the present study showed that the SIRT5-ALDH2 axis plays a critical role in AILI progression and might be a strategy for therapeutic intervention.

Isolation and characterization of a hepatoprotective polysaccharide from Lonicera caerulea L. var. edulis Turcz. ex Herd. fruit against APAP-induced acute liver injury mice

The structure and bioactivities of a novel polysaccharide from Lonicera caerulea L. var. edulis Turcz. ex Herd. fruit (THP-3) were investigated. The crude polysaccharides of Turcz. ex Herd. (THP) were extracted by hot water extraction. After purification, the chemical structure of polysaccharides was identified. Then, a mouse model of acute drug-induced liver injury was constructed using 4-acetamidophenol (APAP) and pretreated with THP. The number-average molecular weight of THP-3 was 48.89 kDa and the mass average molar mass was 97.87 kDa. THP-3 was mainly composed of arabinose (42.54 %), glucose (27.62 %), galacturonic acid and galactose (29.84 %). The main linkage types of THP-3 were 1-linked Araf, 1,4-linked Glcp, and 1,3,6-linked Galp. In addition, after THP treatment, serum Alanine aminotransferase (ALT), Aspartate aminotransferase (AST) and γ-glutamyl transpeptidase (γGT) in AILI mice were successfully down-regulated. The results showed that THP could prevent the characteristic morphological changes of hepatic lobular injury and lipid depletion caused by APAP, reduced the level of oxidative damage in mice, increased the expression of APAP-induced hypolipidemia and related inflammatory indicators, and improved the detoxification function of liver. In general, the newly extracted THP polysaccharide has a good liver protection effect and is an ideal natural medicine for the treatment of liver diseases.

Effect of ferroptosis inhibitors in a murine model of acetaminophen-induced liver injury

Liver injury caused by acetaminophen (APAP) overdose is the leading cause of acute liver failure in western countries. The mode of APAP-induced cell death has been controversially discussed with ferroptosis emerging as a more recent hypothesis. Ferroptosis is characterized by ferrous iron-catalyzed lipid peroxidation (LPO) causing cell death, which can be prevented by the lipophilic antioxidants ferrostatin-1 and UAMC-3203. To assess the efficacy of these ferroptosis inhibitors, we used two murine models of APAP hepatotoxicity, APAP overdose alone or in combination with FeSO4 in fasted male C57BL/6J mice. APAP triggered severe liver injury in the absence of LPO measured as hepatic malondialdehyde (MDA) levels. In contrast, ferrous iron co-treatment aggravated APAP-induced liver injury and caused extensive LPO. Standard doses of ferrostatin-1 did not affect MDA levels or the injury in both models. In contrast, UAMC-3203 partially protected in both models and reduced LPO in the presence of ferrous iron. However, UAMC-3203 attenuated the translocation of phospho-JNK through downregulation of the mitochondrial anchor protein Sab resulting in reduced mitochondrial dysfunction and liver injury. Thus, APAP toxicity does not involve ferroptosis under normal conditions. The lack of effects of ferroptosis inhibitors in the pathophysiology indicates that ferroptosis signaling pathways are not relevant therapeutic targets.

Adenosine kinase protects against acetaminophen-induced acute liver injury by activating autophagy in hepatocytes

Acute liver injury (ALI) is a common life-threatening condition with a high mortality rate due to liver disease-related death. However, current therapeutic interventions for ALI remain ineffective, and the development of effective novel therapies is urgently needed. Liver samples from patients with drug-induced ALI were collected to detect adenosine kinase (ADK) expression. Male C57BL/6 J mice, hepatocyte-specific ADK knockout (ADKHKO) mice, and their controls (ADKf/f) were exposed to acetaminophen (APAP) and other treatments to investigate the mechanisms of APAP-related ALI. ADK expression was significantly decreased in APAP-injured livers. Hepatocyte-specific ADK deficiency exacerbated APAP-induced ALI, while a gain-of-function approach delivering AAV-ADK, markedly alleviated APAP-induced ALI, as indicated by changes in alanine aminotransferases (ALT) levels, aspartate aminotransferase (AST) levels, neutrophil infiltration and hepatocyte death. This study showed that ADK played a critical role in ALI by activating autophagy through two signaling pathways, the adenosine monophosphate-activated protein kinase (AMPK)-mTOR pathway and the adenosine receptor A1 (ADORA1)-Akt-mTOR pathway. Furthermore, we found that metformin upregulated ADK expression in hepatocytes and protected against APAP-induced ALI. These results demonstrate that ADK is critical in protecting against APAP-induced ALI and that developing therapeutics targeting ADK-adenosine-ADORA1 is a new approach for ALI treatment. Metformin is a potential candidate for preventing ALI by upregulating ADK.

Central Mechanisms of Acetaminophen Hepatotoxicity: Mitochondrial Dysfunction by Protein Adducts and Oxidant Stress

Acetaminophen (APAP) is an analgesic and antipyretic drug used worldwide, which is safe at therapeutic doses. However, an overdose can induce liver injury and even liver failure. Mechanistic studies in mice beginning with the seminal papers published by B.B. Brodie's group in the 1970s have resulted in important insight into the pathophysiology. Although the metabolic activation of APAP with generation of a reactive metabolite, glutathione depletion, and protein adduct formation are critical initiating events, more recently, mitochondria have come into focus as an important target and decision point of cell death. This review provides a comprehensive overview of the induction of mitochondrial superoxide and peroxynitrite formation and its propagation through a mitogen-activated protein kinase cascade, the mitochondrial permeability transition pore opening caused by iron-catalyzed protein nitration, and the mitochondria-dependent nuclear DNA fragmentation. In addition, the role of adaptive mechanisms that can modulate the pathophysiology, including autophagy, mitophagy, nuclear erythroid 2 p45-related factor 2 activation, and mitochondrial biogenesis, are discussed. Importantly, it is outlined how the mechanisms elucidated in mice translate to human hepatocytes and APAP overdose patients, and how this mechanistic insight explains the mechanism of action of the clinically approved antidote N-acetylcysteine and led to the recent discovery of a novel compound, fomepizole, which is currently under clinical development. SIGNIFICANCE STATEMENT: Acetaminophen (APAP)-induced liver injury is the most frequent cause of acute liver failure in western countries. Extensive mechanistic research over the last several decades has revealed a central role of mitochondria in the pathophysiology of APAP hepatotoxicity. This review article provides a comprehensive discussion of a) mitochondrial protein adducts and oxidative/nitrosative stress, b) mitochondria-regulated nuclear DNA fragmentation, c) adaptive mechanisms to APAP-induced cellular stress, d) translation of cell death mechanisms to overdose patients, and e) mechanism-based antidotes against APAP-induced liver injury.

GPR116 alleviates acetaminophen-induced liver injury in mice by inhibiting endoplasmic reticulum stress

BACKGROUND

Acetaminophen (APAP) overdose is a significant contributor to drug-induced liver injury worldwide. G-protein-coupled receptor 116 (GPR116) is an important homeostatic maintenance molecule in the body, but little is known about its role in APAP-induced liver injury (AILI).

METHODS

GPR116 expression was determined in both human and mouse AILI models. Hepatic function and damage response were analyzed in hepatocyte-specific GPR116 deletion (GPR116△HC) mice undergoing APAP challenge. RNA-sequencing, immunofluorescence confocal, and co-immunoprecipitation (CO-IP) were employed to elucidate the impact and underlying mechanisms of GPR116 in AILI.

RESULTS

Intrahepatic GPR116 was upregulated in human and mice with AILI. GPR116△HC mice were vulnerable to AILI compared to wild-type mice. Overexpression of GPR116 effectively mitigated AILI in wild-type mice and counteracted the heightened susceptibility of GPR116△HC mice to APAP. Mechanistically, GPR116 inhibits the binding immunoglobulin protein (BiP), a critical regulator of ER function, through its interaction with β-arrestin1, thereby mitigating ER stress during the early stage of AILI. Additionally, the activation of GPR116 by ligand FNDC4 has been shown to confer a protective effect against early hepatotoxicity caused by APAP in murine model.

CONCLUSIONS

Upregulation of GPR116 on hepatocytes inhibits ER stress by binding to β-arrestin1, protecting mice from APAP-induced hepatotoxicity. GPR116 may serve as a promising therapeutic target for AILI.

Susceptibility to Hepatotoxic Drug-Induced Liver Injury Increased After Traumatic Brain Injury in Mice

The early stages of brain injury can induce acute liver injury, which can be recovered in the short term. Continued medication treatment during hospitalization for brain injury alleviates the prognosis and contributes to a high incidence of drug-induced liver injury (DILI). We hypothesize that there is an interaction between changes in the hepatic environment after brain injury and liver injury produced by intensive drug administration, leading to an upregulation of the organism's sensitivity to DILI. In this study, mice models of TBI were established by controlled cortical impact (CCI) and models of DILI were constructed by acetaminophen (APAP). All mice were divided into four groups: Sham, TBI, APAP, and TBI+APAP, and related liver injury indicators in liver and serum were detected by Western blot, Quantitative real-time PCR (qRT-PCR), and immunohistochemical staining. The results suggested that liver injury induced in the early stages of brain injury recovered in 3 days, but this state could still significantly aggravate DILI, represented by higher liver enzymes (aspartate aminotransferase [AST] and alanine aminotransferase [ALT]), oxidative stress (increase in malondialdehyde [MDA] concentration and deregulation of glutathione [GSH] and superoxide dismutase [SOD] activities), inflammatory response (activation of the HMGB1/TLR4/NF-κB signaling pathway, and increased messenger RNA [mRNA] and protein levels of pro-inflammatory cytokines including tumor necrosis factor alpha [TNF-α], interleukin [IL]-6, and IL-1β), and apoptosis (TUNEL assay, upregulation of Bax protein and deregulation of Bcl-2 protein). In summary, our results suggested that TBI is a potential susceptibility factor for DILI and exacerbates DILI.

Multi-omics reveals that 5-O-methylvisammioside prevention acute liver injury in mice by regulating the TNF/MAPK/NF-κB/arachidonic acid pathway

BACKGROUND

The pathogenesis of acute liver injury (ALI) has been a pressing issue in the medical scientific community. We previously found that 5-O-methylvisammioside (MeV) from Saposhnikovia divaricata (Turcz.) Schischk has excellent anti-inflammatory properties. However, the mechanism by which MeV protects against ALI still needs to be deeply investigated.

PURPOSE

In the present study, we established an acetaminophen (APAP) -induced ALI mouse model and pre-protected the mice with MeV.

METHODS & RESULTS

Our findings indicate that MeV (5 and 10 mg/kg) lowered the blood levels of alanine aminotransferase and aspartate aminotransferase and reduced the infiltration of inflammatory cells in the liver. MeV initially showed an inhibitory effect on ALI. We then analyzed the molecular mechanisms underlying the effects of MeV by transcriptomic and metabolomic analyzes. Through transcriptomic analysis, we identified 4675 differentially expressed genes between the APAP+MeV group and the APAP-induced ALI group, which were mainly enriched in the MAPK pathway, the TNF pathway, and the NF-κB pathway. Through metabolomic analysis, we found that 249 metabolites in the liver were differentially regulated between the APAP+MeV group and the APAP- induced ALI group, which were mainly enriched in the arachidonic acid pathway. The mRNA expression levels of key genes (encoding TNF-α, p38, AP-1, RelB, IL-1β, and Ptges), as determined by RT-PCR analysis, were consistent with the RNA-seq data. The ELISA results indicate that MeV markedly decreased the serum levels of TNF-α and IL-1β in mice. Finally, the key proteins in the NF-κB and MAPK pathways were examined using immunoblotting. The results showed that MeV decreased IκB-α phosphorylation and inhibited the nuclear translocation of NF-κB. In addition, MeV reduced the hepatic inflammatory burst mainly by inhibiting the phosphorylation of p38 and JNK in the MAPK pathway.

CONCLUSION

The present study demonstrated (i) that MeV could ameliorate APAP-induced ALI by inhibiting arachidonic acid metabolism and the TNF, MAPK, and NF-κB pathways, and (ii) that MeV is a promising drug candidate for the prevention of ALI.

Acetaminophen overdose-induced acute liver injury can be alleviated by static magnetic field

Acetaminophen (APAP), the most frequently used mild analgesic and antipyretic drug worldwide, is implicated in causing 46% of all acute liver failures in the USA and between 40% and 70% in Europe. The predominant pharmacological intervention approved for mitigating such overdose is the antioxidant N-acetylcysteine (NAC); however, its efficacy is limited in cases of advanced liver injury or when administered at a late stage. In the current study, we discovered that treatment with a moderate intensity static magnetic field (SMF) notably reduced the mortality rate in mice subjected to high-dose APAP from 40% to 0%, proving effective at both the initial liver injury stage and the subsequent recovery stage. During the early phase of liver injury, SMF markedly reduced APAP-induced oxidative stress, free radicals, and liver damage, resulting in a reduction in multiple oxidative stress markers and an increase in the antioxidant glutathione (GSH). During the later stage of liver recovery, application of vertically downward SMF increased DNA synthesis and hepatocyte proliferation. Moreover, the combination of NAC and SMF significantly mitigated liver damage induced by high-dose APAP and increased liver recovery, even 24 h post overdose, when the effectiveness of NAC alone substantially declines. Overall, this study provides a non-invasive non-pharmaceutical tool that offers dual benefits in the injury and repair stages following APAP overdose. Of note, this tool can work as an alternative to or in combination with NAC to prevent or minimize liver damage induced by APAP, and potentially other toxic overdoses.

Biological Functions and Potential Therapeutic Significance of O-GlcNAcylation in Hepatic Cellular Stress and Liver Diseases

O-linked-β-D-N-acetylglucosamine (O-GlcNAc) glycosylation (O-GlcNAcylation), which is dynamically regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA), is a post-translational modification involved in multiple cellular processes. O-GlcNAcylation of proteins can regulate their biological functions via crosstalk with other post-translational modifications, such as phosphorylation, ubiquitination, acetylation, and methylation. Liver diseases are a major cause of death worldwide; yet, key pathological features of the disease, such as inflammation, fibrosis, steatosis, and tumorigenesis, are not fully understood. The dysregulation of O-GlcNAcylation has been shown to be involved in some severe hepatic cellular stress, viral hepatitis, liver fibrosis, nonalcoholic fatty acid liver disease (NAFLD), malignant progression, and drug resistance of hepatocellular carcinoma (HCC) through multiple molecular signaling pathways. Here, we summarize the emerging link between O-GlcNAcylation and hepatic pathological processes and provide information about the development of therapeutic strategies for liver diseases.

Cynarin alleviates acetaminophen-induced acute liver injury through the activation of Keap1/Nrf2-mediated lipid peroxidation defense via the AMPK/SIRT3 signaling pathway

Overdose of Acetaminophen (APAP) is a major contributor to acute liver injury (ALI), a complex pathological process with limited effective treatments. Emerging evidence links lipid peroxidation to APAP-induced ALI. Cynarin (Cyn), a hydroxycinnamic acid derivative, exhibits liver protective effects, but whether it mitigates APAP-induced ALI is unclear. Our aim was to verify the protective impact of Cyn on APAP-induced ALI and elucidate the molecular mechanisms governing this process. Herein, the regulation of the Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) interaction was determined to be a novel mechanism underlying this protective impact of Cyn against APAP-induced ALI. Nrf2 deficiency increased the severity of APAP-induced ALI and lipid peroxidation and counteracted the protective effect of Cyn against this pathology. Additionally, Cyn promoted the dissociation of Nrf2 from Keap1, enhancing the nuclear translocation of Nrf2 and the transcription of downstream antioxidant proteins, thereby inhibiting lipid peroxidation. Molecular docking demonstrated that Cyn bound competitively to Keap1, and overexpression of Keap1 reversed Nrf2-activated anti-lipid peroxidation. Additionally, Cyn activated the adenosine monophosphate-activated protein kinase (AMPK)/sirtuin (SIRT)3 signaling pathway, which exhibits a protective effect on APAP-induced ALI. These findings propose that Cyn alleviates APAP-induced ALI by enhancing the Keap1/Nrf2-mediated lipid peroxidation defense via activation of the AMPK/SIRT3 signaling pathway.

Inhibition of ALK3-mediated signalling pathway protects against acetaminophen-induced liver injury

Acetaminophen (APAP)-induced liver injury is one of the most prevalent causes of acute liver failure (ALF). We assessed the role of the bone morphogenetic protein (BMP) type I receptors ALK2 and ALK3 in APAP-induced hepatotoxicity. The molecular mechanisms that regulate the balance between cell death and survival and the response to oxidative stress induced by APAP was assessed in cultured human hepatocyte-derived (Huh7) cells treated with pharmacological inhibitors of ALK receptors and with modulated expression of ALK2 or ALK3 by lentiviral infection, and in a mouse model of APAP-induced hepatotoxicity. Inhibition of ALK3 signalling with the pharmacological inhibitor DMH2, or by silencing of ALK3, showed a decreased cell death both by necrosis and apoptosis after APAP treatment. Also, upon APAP challenge, ROS generation was ameliorated and, thus, ROS-mediated JNK and P38 MAPK phosphorylation was reduced in ALK3-inhibited cells compared to control cells. These results were also observed in an experimental model of APAP-induced ALF in which post-treatment with DMH2 after APAP administration significantly reduced liver tissue damage, apoptosis and oxidative stress. This study shows the protective effect of ALK3 receptor inhibition against APAP-induced hepatotoxicity. Furthermore, findings obtained from the animal model suggest that BMP signalling might be a new pharmacological target for the treatment of ALF.

Hepatic Sirt6 activation abrogates acute liver failure

Acute liver failure (ALF) is a deadly illness due to insufficient detoxification in liver induced by drugs, toxins, and other etiologies, and the effective treatment for ALF is very limited. Among the drug-induced ALF, acetaminophen (APAP) overdose is the most common cause. However, the molecular mechanisms underlying APAP hepatoxicity remain incompletely understood. Sirtuin 6 (Sirt6) is a stress responsive protein deacetylase and plays an important role in regulation of DNA repair, genomic stability, oxidative stress, and inflammation. Here, we report that genetic and pharmacological activation of Sirt6 protects against ALF in mice. We first observed that Sirt6 expression was significantly reduced in the liver tissues of human patients with ALF and mice treated with an overdose of APAP. Then we developed an inducible Sirt6 transgenic mice for Cre-mediated overexpression of the human Sirt6 gene in systemic (Sirt6-Tg) and hepatic-specific (Sirt6-HepTg) manners. Both Sirt6-Tg mice and Sirt6-HepTg mice exhibited the significant protection against APAP hepatoxicity. In contrast, hepatic-specific Sirt6 knockout mice exaggerated APAP-induced liver damages. Mechanistically, Sirt6 attenuated APAP-induced hepatocyte necrosis and apoptosis through downregulation of oxidative stress, inflammation, the stress-activated kinase JNK activation, and apoptotic caspase activation. Moreover, Sirt6 negatively modulated the level and activity of poly (ADP-ribose) polymerase 1 (PARP1) in APAP-treated mouse liver tissues. Importantly, the specific Sirt6 activator MDL-800 exhibited better therapeutic potential for APAP hepatoxicity than the current drug acetylcysteine. Furthermore, in the model of bile duct ligation induced ALF, hepatic Sirt6-KO exacerbated, but Sirt6-HepTg mitigated liver damage. Collectively, our results demonstrate that Sirt6 protects against ALF and suggest that targeting Sirt6 activation could be a new therapeutic strategy to alleviate ALF.

Cardioprotective and Hepatoprotective Potential of Silymarin in Paracetamol-Induced Oxidative Stress

Silymarin, derived from Silybum marianum, has been used in traditional medicine for various ailments. In this study, the cardioprotective and hepatoprotective effects of silymarin against paracetamol-induced oxidative stress were examined in 28 male Swiss Webster mice, divided into four groups and treated for 7 days (via the oral route) with (a) saline 1 mL/kg (control group), (b) saline 1 mL/kg + single dose of paracetamol 110 mg/kg on the 7th day; (c) silymarin 50 mg/kg; and (d) silymarin 50 mg/kg + single dose of paracetamol 110 mg/kg on the 7th day. In vitro and in vivo antioxidant activity together with liver enzyme activity were evaluated. Histopathological and immunohistochemical assessment was performed. Silymarin mitigated paracetamol-induced liver injury by reducing oxidative stress markers such as lipid peroxidation and restoring antioxidant enzyme activity. Silymarin treatment resulted in a significant decrease in liver enzyme levels. Reduced necrosis and inflammatory infiltrate in liver tissues of silymarin-treated groups were detected as well. Immunohistochemical analysis demonstrated reduced expression of inflammatory markers (COX2, iNOS) and oxidative stress marker (SOD2) in the liver tissues of the silymarin-treated groups. Similar trends were observed in cardiac tissue. These results suggest that silymarin exerts potent hepatoprotective and cardioprotective effects against paracetamol-induced oxidative stress, making it a promising therapeutic agent for liver and heart diseases associated with oxidative damage.

NLRP3 deficiency protects against acetaminophen‑induced liver injury by inhibiting hepatocyte pyroptosis

Acetaminophen (APAP) overdose is the primary cause of drug‑induced acute liver failure in numerous Western countries. NLR family pyrin domain containing 3 (NLRP3) inflammasome activation serves a pivotal role in the pathogenesis of various forms of acute liver injury. However, the cellular source for NLRP3 induction and its involvement during APAP‑induced hepatotoxicity have not been thoroughly investigated. In the present study, hematoxylin and eosin staining was performed to assess histopathological changes of liver tissue. Immunohistochemistry staining(NLRP3, Caspase‑1, IL‑1β, GSDMD and Caspase‑3), western blotting (NLRP3, Caspase‑1, IL‑1β, GSDMD and Caspase‑3) and RT‑qPCR (NLRP3, Caspase‑1 and IL‑1β) were performed to assess the expression of NLRP3/GSDMD signaling pathway. TUNEL staining was performed to assess apoptosis of liver tissue. The serum expression levels of inflammatory factors (IL‑6, IL‑18, IL‑1β and TNF‑α) were assessed using ELISA and inflammation of liver tissue was assessed using immunohistochemistry (Ly6G and CD68) and RT‑qPCR (TNF‑α, Il‑6, Mcp‑1, Cxcl‑1, Cxcl‑2). A Cell Counting Kit‑8 was performed to assess cell viability and apoptosis. Protein and gene expression were analyzed by western blotting (PCNA, CCND1) and RT‑qPCR (CyclinA2, CyclinD1 and CyclinE1). Through investigation of an APAP‑induced acute liver injury model (AILI), the present study demonstrated that APAP overdose induced activation of NLRP3 and cleavage of gasdermin D (GSDMD) in hepatocytes, both in vivo and in vitro. Additionally, mice with hepatocyte‑specific knockout of Nlrp3 exhibited reduced liver injury and lower mortality following APAP intervention, accompanied by decreased infiltration of inflammatory cells and attenuated inflammatory response. Furthermore, pharmacological blockade of NLRP3/GSDMD signaling using MCC950 or disulfiram significantly ameliorated liver injury and reduced hepatocyte death. Notably, hepatocyte Nlrp3 deficiency promoted liver recovery by enhancing hepatocyte proliferation. Collectively, the present study demonstrated that inhibition of the NLRP3 inflammasome protects against APAP‑induced acute liver injury by reducing hepatocyte pyroptosis and suggests that targeting NLRP3 may hold therapeutic potential for treating AILI.

The protective effect of Thai rice bran on N-acetyl-ρ-aminophen-induced hepatotoxicity in mice

Background and purpose

N-acetyl-ρ-aminophen (APAP) is a widely used medication with analgesic and antipyretic characteristics. High paracetamol doses can damage the liver. Thai-pigmented rice may treat numerous liver disorders due to its antioxidant, anti-inflammatory, and glutathione-restoring capabilities. This study aimed to evaluate the phenolic components in three Thai rice bran extracts and their antioxidant and hepatoprotective activities in an animal model.

Experimental approach

Fifty male mice were randomly assigned to the control and APAP studies. Each study was divided into 5 groups (n = 5) treated with distilled water, Hom Mali, Hang-Ngok, and Hom Nil (HN) rice compared with N-acetylcysteine with/without 60 mg/kg/day of APAP orally once a day for two weeks. Blood and liver sampling were collected for analysis.

Findings/Results

HN rice bran exhibited higher contents of total phenolic, total flavonoid, total anthocyanin, ferric-reducing antioxidant, and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activities than Hom Mali and Hang-Ngok. Anthocyanin was merely detected in HN. Following APAP administration, mice exhibited significant increases in hepatic enzymes including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), pro-inflammatory cytokines (tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6)), and malondialdehyde (MDA), but lower levels of antioxidant enzymes and glutathione profiles. Amongst the three cultivars, HN rice was the only compound that decreased MDA, ALT, AST, TNF-α, and IL-6 while increasing antioxidant enzyme activity such as superoxide dismutase, catalase, and glutathione peroxidase that was very close to that of N-acetylcysteine groups.

Conclusion and implications

Given the hepatoprotective and antioxidant properties, HN has the potential to be used as a health supplement.

Multienzyme Active Manganese Oxide Alleviates Acute Liver Injury by Mimicking Redox Regulatory System and Inhibiting Ferroptosis

Drug-induced liver injury (DILI) is a severe condition characterized by impaired liver function and the excessive activation of ferroptosis. Unfortunately, there are limited options currently available for preventing or treating DILI. In this study, MnO2 nanoflowers (MnO2Nfs) with remarkable capabilities of mimicking essential antioxidant enzymes, including catalase, superoxide dismutase (SOD), and glutathione peroxidase are successfully synthesized, and SOD is the dominant enzyme among them by density functional theory. Notably, MnO2Nfs demonstrate high efficiency in effectively eliminating diverse reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), superoxide anion (O2 •-), and hydroxyl radical (•OH). Through in vitro experiments, it is demonstrated that MnO2Nfs significantly enhance the recovery of intracellular glutathione content, acting as a potent inhibitor of ferroptosis even in the presence of ferroptosis activators. Moreover, MnO2Nfs exhibit excellent liver accumulation properties, providing robust protection against oxidative damage. Specifically, they attenuate acetaminophen-induced ferroptosis by inhibiting ferritinophagy and activating the P62-NRF2-GPX4 antioxidation signaling pathways. These findings highlight the remarkable ROS scavenging ability of MnO2Nfs and hold great promise as an innovative and potential clinical therapy for DILI and other ROS-related liver diseases.

Deficiency of ASGR1 promotes liver injury by increasing GP73-mediated hepatic endoplasmic reticulum stress

Liver injury is a core pathological process in the majority of liver diseases, yet the genetic factors predisposing individuals to its initiation and progression remain poorly understood. Here we show that asialoglycoprotein receptor 1 (ASGR1), a lectin specifically expressed in the liver, is downregulated in patients with liver fibrosis or cirrhosis and male mice with liver injury. ASGR1 deficiency exacerbates while its overexpression mitigates acetaminophen-induced acute and CCl4-induced chronic liver injuries in male mice. Mechanistically, ASGR1 binds to an endoplasmic reticulum stress mediator GP73 and facilitates its lysosomal degradation. ASGR1 depletion increases circulating GP73 levels and promotes the interaction between GP73 and BIP to activate endoplasmic reticulum stress, leading to liver injury. Neutralization of GP73 not only attenuates ASGR1 deficiency-induced liver injuries but also improves survival in mice received a lethal dose of acetaminophen. Collectively, these findings identify ASGR1 as a potential genetic determinant of susceptibility to liver injury and propose it as a therapeutic target for the treatment of liver injury.

Design and discovery of a highly potent ultralong-acting GLP-1 and glucagon co-agonist for attenuating renal fibrosis

The role of co-agonists of glucagon-like peptide-1 receptor (GLP-1R) and glucagon receptor (GCGR) in chronic kidney disease (CKD) remains unclear. Herein we found that GLP-1R and GCGR expression levels were lower in the kidneys of mice with CKD compared to healthy mice and were correlated with disease severity. Interestingly, GLP-1R or GCGR knockdown aggravated the progression of kidney injury in both diabetic db/db mice and non-diabetic mice undergoing unilateral ureteral obstruction (UUO). Based on the importance of GLP-1R and GCGR in CKD, we reported a novel monomeric peptide, 1907-B, with dual-agonism on both GLP-1R and GCGR. The data confirmed that 1907-B had a longer half-life than long-acting semaglutide in rats or cynomolgus monkeys (∼2-3 fold) and exhibited better therapeutic contribution to CKD than best-in-class monoagonists, semaglutide, or glucagon, in db/db mice and UUO mice. Various lock-of-function models, including selective pharmacological activation and genetic knockdown, confirmed that 1907-B's effects on ameliorating diabetic nephropathy in db/db mice, as well as inhibiting kidney fibrosis in UUO mice, were mediated through GLP-1 and glucagon signaling. These findings highlight that 1907-B, a novel GLP-1R and GCGR co-agonist, exerts multifactorial improvement in kidney injuries and is an effective and promising therapeutic option for CKD treatment.

Translocation of Adenosine A2B Receptor to Mitochondria Influences Cytochrome P450 2E1 Activity after Acetaminophen Overdose

The adenosine A2B receptor (A2BAR) is a member of a family of G-protein coupled receptors (GPCRs), which has a low affinity for adenosine and is now implicated in several pathophysiological conditions. We have demonstrated the beneficial effects of A2BAR activation in enhancing recovery after acute liver injury induced by an acetaminophen (APAP) overdose. While receptor trafficking within the cell is recognized to play a role in GPCR signaling, its role in the mediation of A2BAR effects in the context of APAP-induced liver injury is not well understood. This was investigated here, where C57BL/6J mice were subjected to an APAP overdose (300 mg/kg), and the temporal course of A2BAR intracellular localization was examined. The impact of A2BAR activation or inhibition on trafficking was examined by utilizing the A2BAR agonist BAY 60-6583 or antagonist PSB 603. The modulation of A2BAR trafficking via APAP-induced cell signaling was explored by using 4-methylpyrazole (4MP), an inhibitor of Cyp2E1 and JNK activation. Our results indicate that APAP overdose induced the translocation of A2BAR to mitochondria, which was prevented via 4MP treatment. Furthermore, we demonstrated that A2BAR is localized on the mitochondrial outer membrane and interacts with progesterone receptor membrane component 1 (PGRMC1). While the activation of A2BAR enhanced mitochondrial localization, its inhibition decreased PGRMC1 mitochondria levels and blunted mitochondrial Cyp2E1 activity. Thus, our data reveal a hitherto unrecognized consequence of A2BAR trafficking to mitochondria and its interaction with PGRMC1, which regulates mitochondrial Cyp2E1 activity and modulates APAP-induced liver injury.

Developing a novel benzothiazole-based red-emitting probe for intravital imaging of superoxide anion

Superoxide anion (O2•-), the first generated reactive oxygen species (ROS), is a critical player in cellular signaling network and redox homeostasis. Imaging of O2•-, particularly in vivo, is of concern for further understanding its roles in pathophysiological and pharmacological events. Herein, we designed a novel probe, (E)-4-(5-(2-(benzo[d]thiazol-2-yl)-2-cyanovinyl)furan-2-yl)phenyl trifluoromethane-sulfonate (BFTF), by modifying hydroxyphenyl benzothiazole (a widely used dye scaffold) which includes insertion of both an acrylonitrile unit and a furan ring to extend the total π-conjugation system and to enhance push-pull intramolecular charge transfer process, and utilization of trifluoromethanesulfonate as the response unit. Toward O2•-, the probe features near-infrared fluorescent emission (685 nm), large Stokes shift (135 nm), and deep tissue penetration (300 μm). With its help, we successfully mapped preferential generation of O2•- in HepG2 cells over L02 cells, as well as in A549 over BEAS-2B cells by β-lapachone (an anticancer agent that generates O2•-), and more importantly, visualized overproduction of O2•- in living mice with liver injury induced by acetaminophen (a well-known analgesic and antipyretic drug).

The pharmacology activities of Angelica keiskei Koidzumi and its efficacy and safety in humans

Chronic exposure to elevated levels of pro-oxidant factors may cause structural failings at the mitochondrial DNA level and alteration of antioxidant enzymes (glutathione peroxidase, catalase, and superoxide dismutase). Oxidative stress is an imbalance between the capacity of endogenous non-enzymatic antioxidants (glutathione, alpha-lipoic acid, uric acid, ferritin, metallothionein, melatonin, and bilirubin) and the occurrence of pro-oxidant factors which may lead to the pathogenesis of various diseases that affects the kidneys, pancreas, central nervous system, and cardiovascular system. Therefore, the utilization of medicinal plants with antioxidant activity, e.g., Angelica keiskei Koidzumi which contains chalcones, is interesting to be explored. Chalcones exhibit direct and indirect antioxidant activity and prevent oxidative stress by decreasing ROS, RNS, and superoxide production. In this review, we discuss the pharmacology activities of A. keiskei Koidzumi and its efficacy in humans. The articles were explored on PubMed and Google Scholar databases and based on the titles and abstracts related to the topic of interest, and 55 articles were selected. Two main chalcones of this plant, 4-hydroxyderricin and xanthoangelol, have been reported for their various pharmacology activities. The efficacy of A. keiskei was confirmed in anti-obesity, hepatoprotective, anti-diabetes mellitus, and increasing plasma antioxidants in patients with metabolic syndrome. A keiskei is safe as proven by only mild or no adverse events reported, thus it is prospective to be further developed as an antioxidant nutraceutical.

Activatable fluorescent probes for early diagnosis and evaluation of liver injury

With the increase in people's living standards, the number of patients suffering from liver injury keeps on increasing. Traditional diagnostic methods can no longer meet the needs of early and accurate diagnosis due to their limitations in application. However, fluorescent probes based on different fluorophores and nanomaterials have been gradually lighting up medical research due to their unique properties, such as high specificity and non-invasiveness. In addition, accurate identification of the different types of liver injury biomarkers can significantly improve the level of early diagnosis. Therefore, this review reviews the fluorescent probes used in the detection of biomarkers of liver injury over recent years and briefly summarizes the corresponding biomarkers of different types of liver injury. Impressively, this review also lists the structures and the response mechanisms of the different probes, and concludes with an outlook, suggesting directions in which improvements can be made. Finally, we hope that this review will contribute to the further development of fluorescent probes for the early diagnosis and assessment of liver injury.

Screening of Multitarget Compounds against Acetaminophen Hepatic Toxicity Using In Silico, In Vitro, and In Vivo Approaches

Combination therapy and multitarget drugs have recently attracted much attention as promising tools to fight against many challenging diseases and, thus, represent a new research focus area. The aim of the current project was to screen multitarget compounds and to study their individual and combined effects on acetaminophen-induced liver injury. In this study, 2 of the best hepatoprotective multitargeting compounds were selected from a pool of 40 major compounds present in Curcuma longa and Cinnamomum zeylanicum by using molecular docking, ADMET profiling, and Pfizer's rule of five. The two selected compounds, quercetin and curcumin, showed a high binding affinity for the CYP2E1 enzyme, MAPK, and TLR4 receptors that contribute to liver injury. The candidates caused the decreased viability of cancer cell lines (HepG2 and Huh7) but showed no effect on a normal cell line (Vero). Examination of biochemical parameters (ALT, AST, ALP, and bilirubin) showed the hepatoprotective effect of the candidate drugs in comparison with the control group, which was confirmed by histological findings. Taken together, quercetin and curcumin not only satisfied the drug-like assessment criterion and proved to be multitargeting by preventing liver damage but also showed anticancer activities.

Contributing roles of mitochondrial dysfunction and hepatocyte apoptosis in liver diseases through oxidative stress, post-translational modifications, inflammation, and intestinal barrier dysfunction

This review provides an update on recent findings from basic, translational, and clinical studies on the molecular mechanisms of mitochondrial dysfunction and apoptosis of hepatocytes in multiple liver diseases, including but not limited to alcohol-associated liver disease (ALD), metabolic dysfunction-associated steatotic liver disease (MASLD), and drug-induced liver injury (DILI). While the ethanol-inducible cytochrome P450-2E1 (CYP2E1) is mainly responsible for oxidizing binge alcohol via the microsomal ethanol oxidizing system, it is also responsible for metabolizing many xenobiotics, including pollutants, chemicals, drugs, and specific diets abundant in n-6 fatty acids, into toxic metabolites in many organs, including the liver, causing pathological insults through organelles such as mitochondria and endoplasmic reticula. Oxidative imbalances (oxidative stress) in mitochondria promote the covalent modifications of lipids, proteins, and nucleic acids through enzymatic and non-enzymatic mechanisms. Excessive changes stimulate various post-translational modifications (PTMs) of mitochondrial proteins, transcription factors, and histones. Increased PTMs of mitochondrial proteins inactivate many enzymes involved in the reduction of oxidative species, fatty acid metabolism, and mitophagy pathways, leading to mitochondrial dysfunction, energy depletion, and apoptosis. Unique from other organelles, mitochondria control many signaling cascades involved in bioenergetics (fat metabolism), inflammation, and apoptosis/necrosis of hepatocytes. When mitochondrial homeostasis is shifted, these pathways become altered or shut down, likely contributing to the death of hepatocytes with activation of inflammation and hepatic stellate cells, causing liver fibrosis and cirrhosis. This review will encapsulate how mitochondrial dysfunction contributes to hepatocyte apoptosis in several types of liver diseases in order to provide recommendations for targeted therapeutics.

Protective effect of Tibetan medicine Qiwei Tiexie pills on liver injury induced by acetaminophen overdose: An integrated strategy of network pharmacology, metabolomics and transcriptomics

BACKGROUND

Drug-induced liver injury, particularly from acetaminophen (APAP), has emerged as a significant public health concern. Unfortunately, there is currently no effective treatment strategy available. Qiwei Tiexie pills (QWTX), a traditional Tibetan medicine, have demonstrated considerable clinical efficacy in treating various liver diseases. Nevertheless, the protective effect of QWTX against drug-induced liver injury and its underlying mechanism remains poorly understood.

PURPOSE

This study aimed to assess the therapeutic potential of QWTX, a Tibetan medicine, in an animal model of APAP-induced liver injury. Additionally, we sought to investigate the molecular mechanism through which QWTX exerts its effects.

METHODS

We employed LC-MS and network pharmacology to predict the potential targets of QWTX in drug-induced liver injury. Subsequently, we employed HE staining, transcriptomics, metabolomics, and qRT-PCR to analyze the mechanism underlying QWTX treatment in drug-induced liver injury.

RESULTS

Network pharmacology analysis revealed that the active components of QWTX are involved in inflammatory and drug metabolism-related pathways. In mouse models, pretreatment with QWTX effectively mitigated the elevated levels of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), and inflammatory factors (IL-1β, IL-6, and TNF-α) induced by APAP overdose. Moreover, APAP inhibited 1459 differentially expressed genes (DEGs) and 874 differential accumulation metabolites (DAMs), while QWTX promoted their expression. Conversely, APAP promoted 874 genes and 119 metabolites, which were inhibited by QWTX. Further analysis demonstrated that QWTX ameliorated the metabolic disorders induced by APAP overdose and potentially exerted a protective effect by inhibiting the expression of critical genes in crucial inflammatory pathways. QWTX also up-regulated antioxidant enzymes, thereby mitigating the oxidative stress resulting from APAP overdose.

CONCLUSION

QWTX treatment effectively protects against APAP-induced liver damage in mice. Transcriptomic and metabolomic analyses further revealed that QWTX ameliorated hepatic metabolic disorders induced by APAP overdose while significantly suppressing the inflammatory response and oxidative stress associated with drug-induced liver injury. This study provides a new insight into the treatment of drug-induced liver injury by the TCM system and provides a basis for the development of new therapies for drug-induced liver injury by QWTX and its active ingredients.

Phenelzine protects against acetaminophen induced apoptosis in HepG2 cells

Acetaminophen (APAP) overdosing is the most common cause of drug-induced liver failure. Despite extensive study, N-acetylcysteine is currently the only antidote utilized for treatment. The purpose of this study was to evaluate the effect and mechanisms of phenelzine, an FDA-approved antidepressant, on APAP-induced toxicity in HepG2 cells. The human liver hepatocellular cell line HepG2 was used to investigate APAP-induced cytotoxicity. The protective effects of phenelzine were determined by examining the cell viability, combination index calculation, Caspase 3/7 activation, Cytochrome c release, H2O2 levels, NO levels, GSH activity, PERK protein levels, and pathway enrichment analysis. Elevated H2O2 production and decreased glutathione (GSH) levels were indicators of APAP-induced oxidative stress. The combination index of 2.04 indicated that phenelzine had an antagonistic effect on APAP-induced toxicity. When compared to APAP alone, phenelzine treatment considerably reduced caspase 3/7 activation, cytochrome c release, and H2O2 generation. However, phenelzine had minimal effect on NO and GSH levels and did not alleviate ER stress. Pathway enrichment analysis revealed a potential connection between APAP toxicity and phenelzine metabolism. These findings suggested that phenelzine's protective effect against APAP-induced cytotoxicity could be attributed to the drug's capacity to reduce APAP-mediated apoptotic signaling.

Smart antioxidant function enhancing (SAFE) nucleic acid therapy for ROS-related chronic diseases and comorbidities

Reactive oxygen species (ROS)-mediated oxidative stress exacerbates chronic diseases such as organ damage and neurodegenerative disorders. The Keap1-Nrf2-ARE pathway is a widely distributed endogenous antioxidant system. However, ROS under redox homeostasis regulates a wide range of life activities. Therefore, smart scavenging of excess ROS under pathological conditions is essential to treat chronic diseases safely. This study reports a smart antioxidant function enhancement (SAFE) strategy. On-demand release of nucleic acid drugs in a pathological ROS environment smartly activates the endogenous antioxidant system, thereby smartly alleviating oxidative stress in an exogenous antioxidant-independent manner. Through structural modulation and ligand modification, we develop SAFE nanoparticles based on nanohybrid complexes (SAFE-complex) adapted to brain delivery of nucleic acid drugs. SAFE-complex with homogeneous monodisperse structure efficiently treat ROS-related neurodegenerative diseases while protecting the major organ from oxidative stress damage. Moreover, SAFE-complex can stabilize storage in the form of freeze-dried powder. These data indicate that SAFE nanoparticles hold promise for treating ROS-related chronic diseases and comorbidities through rational transformation.

Prospective Application of Tannic Acid in Acetaminophen (APAP)-Induced Acute Liver Failure

This study investigated the effect of tannic acid (TA), a natural plant-derived polyphenol, on hepatocyte viability and function, focusing on both hepatoprotective and hepatocurative aspects within liver failure models. In an in vitro prevention model, the TA-containing group exhibited 1.5-fold and 59-fold higher relative cell viability and albumin synthesis, respectively, in injured mature hepatocytes (MHs) and 1.14-fold and 1.10-fold higher values in injured small hepatocytes (SHs), compared with the TA-free group. In the in vitro curative model, the TA-containing group exhibited 3.25-fold and 113-fold higher relative cell viability and albumin synthesis, respectively, in injured MHs and 0.36-fold and 3.55-fold higher values in injured SHs, compared with the TA-free group. In the in vivo disease model, the administration of 300 μL of 1 μg/mL TA significantly mitigated acute liver failure damage and post-APAP toxicity in mice. This was evident in serum analysis, where the levels of alanine transaminase, aspartate aminotransferase, and total bilirubin notably decreased, in agreement with histological observations. The study findings reveal that TA can enhance hepatic function at specific additive concentrations. Furthermore, even when injured by APAP, hepatocytes could revert to their preinjury state after additional TA supplementation. Additionally, pretreating hepatocytes with TA can alleviate subsequent damage. Thus, TA holds clinical potential in the treatment of APAP-induced liver failure.

Hepatocyte-specific deletion of small heterodimer partner protects mice against acetaminophen-induced hepatotoxicity via activation of Nrf2

Acetaminophen (APAP) overdose stands as the primary cause of acute liver failure in the United States. APAP hepatotoxicity involves hepatic glutathione (GSH) depletion and mitochondrial damage. To counteract the toxicity of APAP, the nuclear factor erythroid 2 like 2 (Nrf2) activates the expression of genes responsible for drug detoxification and GSH synthesis. In this study, we present evidence that the elimination of hepatocyte small heterodimer partner, a critical transcriptional repressor for liver metabolism, results in Nrf2 activation and protects mice from APAP-induced acute liver injury. Initial investigations conducted on wildtype (WT) mice revealed a swift downregulation of Shp mRNA within the first 24 h after APAP administration. Subsequent treatment of hepatocyte-specific Shp knockout (ShpHep-/-) mice with 300 mg/kg APAP for 2 h exhibited comparable bioactivation of APAP with that observed in the WT controls. However, a significant reduction in liver injury was observed in ShpHep-/- after APAP treatment for 6 and 24 h. The decreased liver injury correlated with a faster recovery of GSH, attributable to heightened expression of Nrf2 target genes involved in APAP detoxification and GSH synthesis. Moreover, in vitro studies revealed that SHP protein interacted with NRF2 protein, inhibiting the transcription of Nrf2 target genes. These findings hold relevance for humans, as overexpression of SHP hindered APAP-induced NRF2 activation in primary human hepatocytes. In conclusion, our studies have unveiled a novel regulatory axis involving SHP and NRF2 in APAP-induced acute liver injury, emphasizing SHP as a promising therapeutic target in APAP overdose-induced hepatotoxicity.

Glutaredoxin-1 alleviates acetaminophen-induced liver injury by decreasing its toxic metabolites

Excessive N-acetyl-p-benzoquinone imine (NAPQI) formation is a starting event that triggers oxidative stress and subsequent hepatocyte necrosis in acetaminophen (APAP) overdose caused acute liver failure (ALF). S-glutathionylation is a reversible redox post-translational modification and a prospective mechanism of APAP hepatotoxicity. Glutaredoxin-1 (Glrx1), a glutathione-specific thioltransferase, is a primary enzyme to catalyze deglutathionylation. The objective of this study was to explored whether and how Glrx1 is associated with the development of ALF induced by APAP. The Glrx1 knockout mice (Glrx1-/-) and liver-specific overexpression of Glrx1 (AAV8-Glrx1) mice were produced and underwent APAP-induced ALF. Pirfenidone (PFD), a potential inducer of Glrx1, was administrated preceding APAP to assess its protective effects. Our results revealed that the hepatic total protein S-glutathionylation (PSSG) increased and the Glrx1 level reduced in mice after APAP toxicity. Glrx1-/- mice were more sensitive to APAP overdose, with higher oxidative stress and more toxic metabolites of APAP. This was attributed to Glrx1 deficiency increasing the total hepatic PSSG and the S-glutathionylation of cytochrome p450 3a11 (Cyp3a11), which likely increased the activity of Cyp3a11. Conversely, AAV8-Glrx1 mice were defended against liver damage caused by APAP overdose by inhibiting the S-glutathionylation and activity of Cyp3a11, which reduced the toxic metabolites of APAP and oxidative stress. PFD precede administration upregulated Glrx1 expression and alleviated APAP-induced ALF by decreasing oxidative stress. We have identified the function of Glrx1 mediated PSSG in liver injury caused by APAP overdose. Increasing Glrx1 expression may be investigated for the medical treatment of APAP-caused hepatic injury.

Targeting ferroptosis by poly(acrylic) acid coated Mn3O4 nanoparticles alleviates acute liver injury

Ferroptosis, a newly characterized form of regulated cell death, is induced by excessive accumulation of lipid peroxidation catalyzed by intracellular bioactive iron. Increasing evidence has suggested that ferroptosis is involved in the pathogenesis of several human diseases, including acute liver injury. Targeted inhibition of ferroptosis holds great promise for the clinical treatment of these diseases. Herein, we report a simple and one-pot synthesis of ultrasmall poly(acrylic) acid coated Mn3O4 nanoparticles (PAA@Mn3O4-NPs, PMO), which perform multiple antioxidant enzyme-mimicking activities and can scavenge broad-spectrum reactive oxygen species. PMO could potently suppress ferroptosis. Mechanistically, after being absorbed mainly through macropinocytosis, PMO are largely enriched in lysosomes, where PMO detoxify ROS, inhibit ferritinophagy-mediated iron mobilization and preserve mTOR activation, which collectively confer the prominent inhibition of ferroptosis. Additionally, PMO injection potently counteracts lipid peroxidation and alleviates acetaminophen- and ischaemia/reperfusion-induced acute liver injury in mice. Collectively, our results reveal that biocompatible PMO act as potent ferroptosis inhibitors through multifaceted mechanisms, which ensures that PMO have great translational potential for the clinical treatment of ferroptosis-related acute liver injury.

Antioxidative and Anti-Inflammatory Protective Effects of Fucoxanthin against Paracetamol-Induced Hepatotoxicity in Rats

Paracetamol or acetaminophen (PAC) is a commonly used analgesic and antipyretic drug. It has been shown that overdoses beyond the therapeutic range can cause hepatotoxicity and acute liver injury. The most common cause of drug-induced liver injury (DILI) in Saudi Arabia and worldwide is paracetamol overdose. Fucoxanthin (FUC) is an allenic carotenoid that is found in edible brown seaweeds, and it has antioxidant and anti-inflammatory effects. Several studies have shown the potential therapeutic effects of FUC in diabetes, cancers, and inflammatory disorders. This study aims to investigate the protective effect of FUC against PAC-induced acute liver injury in rats. FUC was administered (100, 200, and 500 mg/kg, p.o.) for 7 days, and then the liver injury was induced by the administration of PAC (2000 mg/kg, oral). Blood and liver tissue samples were collected from PAC-positive untreated, treated, and negative control rats. Biochemical and inflammatory parameters in the blood were measured. In addition, RT-PCR, Western blotting, and immunohistochemistry were performed for liver tissue. The serum levels of liver biomarkers (ALT, AST, and ALP) increased after PAC-induced liver toxicity; FUC-treated rats showed lower levels compared to the positive control. There was an increase in the expression of TNF-α, IL-1, IL-6, NF-kB, INF-γ, and iNOS and a decrease in IL-10, IL-22, and IL-10R expression after the FUC treatment of injured liver rats. For the hepatic inflammation and PAC-toxicity-induced oxidative stress genes and proteins, FUC-treated rats (100, 200, and 500 mg/kg) showed a reduction in the expression of oxidative stress genes. These results showed that FUC protected the liver against PAC-induced injury through antioxidant and anti-inflammatory actions. However, further clinical studies are required to confirm the findings.

Illumination of Hydroxyl Radical in Kidney Injury and High-Throughput Screening of Natural Protectants Using a Fluorescent/Photoacoustic Probe

The hydroxyl radical (•OH) is shown to play a crucial role in the occurrence and progression of acute kidney injury (AKI). Therefore, the development of a robust •OH probe holds great promise for the early diagnosis of AKI, high-throughput screening (HTS) of natural protectants, and elucidating the molecular mechanism of intervention in AKI. Herein, the design and synthesis of an activatable fluorescent/photoacoustic (PA) probe (CDIA) for sensitive and selective imaging of •OH in AKI is reported. CDIA has near-infrared fluorescence/PA channels and fast activation kinetics, enabling the detection of the onset of •OH in an AKI model. The positive detection time of 12 h using this probe is superior to the 48-hour detection time for typical clinical assays, such as blood urea nitrogen and serum creatinine detection. Furthermore, a method is established using CDIA for HTS of natural •OH inhibitors from herbal medicines. Puerarin is screened out by activating the Sirt1/Nrf2/Keap1 signaling pathway to protect renal cells in AKI. Overall, this work provides a versatile and dual-mode tool for illuminating the •OH-related pathological process in AKI and screening additional compounds to prevent and treat AKI.

A dual-channel fluorescence probe for simultaneously visualizing cysteine and viscosity during drug-induced hepatotoxicity

Cysteine (Cys), one of the important participants in protecting cells from oxidative stress, is closely associated with the occurrence and development of various diseases. Moreover, cell viscosity as a pivotal microenvironmental parameter has recently attracted increasing attention due to its dominant role in governing intracellular signal transduction and diffusion of reactive metabolites. Thus, simultaneous detection of Cys and viscosity is imperative for investigating their pathophysiological functions and cross-link. Herein we present a mitochondria-targetable dual-channel fluorescence probe ABDSP by grafting the acrylate modified pyridinium unit to dimethylaminobenzene. Whilst the probe is a seemingly simple, it could simultaneously discriminate Cys and viscosity in a fashion of distinguishable signals. Furthermore, the probe was successfully employed for visualizing mitochondrial Cys and viscosity, and probe into their cross-link during acetaminophen-induced hepatotoxicity.

Anti-microbial resistance and aging-A design for evolution

The emergence of resistance to anti-infective agents poses a significant threat to successfully treating infections caused by bacteria. Bacteria acquire random mutations due to exposure to environmental stresses, which may increase their fitness to other selection pressures. Interestingly, for bacteria, the frequency of anti-microbial resistance (AMR) seems to be increasing in tandem with the human lifespan. Based on evidence from previous literature, we speculate that increased levels of free radicals (Reactive Oxygen Species-ROS and Reactive Nitrosative Species-RNS), elevated inflammation, and the altered tissue microenvironment in aged individuals may drive pathogen mutagenesis. If these mutations result in the hyperactivation of efflux pumps or alteration in drug target binding sites, it could confer AMR, thus rendering antibiotic therapy ineffective while leading to the selection of novel drug-resistant variants. This article is categorized under: Immune System Diseases > Genetics/Genomics/Epigenetics Infectious Diseases > Environmental Factors Metabolic Diseases > Environmental Factors.

Fructose as a novel nutraceutical for acetaminophen (APAP)-induced hepatotoxicity

Acetaminophen (APAP) is the most widely used analgesic in the world. APAP overdose can cause severe hepatotoxicity and therefore is the most common cause of drug-induced liver injury. The only approved treatment for APAP overdose is N-acetyl-cysteine (NAC) supplementation. However, the narrow efficacy window of the drug severely limits its clinical use, prompting the search for other therapeutic options to counteract APAP toxicity. Recent research has pointed to fructose as a novel nutraceutical for APAP-induced liver injury. This review summarizes the current understanding of the molecular mechanisms underlying APAP-induced liver injury, introduces how fructose supplementation could prevent and treat APAP liver toxicity with a focus on the ChREBPα-FGF21 pathway, and proposes possible future directions of study.

Ethanol Extract of Rosa rugosa Ameliorates Acetaminophen-Induced Liver Injury via Upregulating Sirt1 and Subsequent Potentiation of LKB1/AMPK/Nrf2 Cascade in Hepatocytes

Acetaminophen (APAP)-induced liver injury is a common hepatic disease resulting from drug abuse. Few targeted treatments are available clinically nowadays. The flower bud of Rosa rugosa has a wide range of biological activities. However, it is unclear whether it alleviates liver injury caused by APAP. Here, we prepared an ethanol extract of Rosa rugosa (ERS) and analyzed its chemical profile. Furthermore, we revealed that ERS significantly ameliorated APAP-induced apoptosis and ferroptosis in AML-12 hepatocytes and dampened APAP-mediated cytotoxicity. In AML-12 cells, ERS elevated Sirt1 expression, boosted the LKB1/AMPK/Nrf2 axis, and thereby crippled APAP-induced intracellular oxidative stress. Both EX527 and NAM, which are chemically unrelated inhibitors of Sirt1, blocked ERS-induced activation of LKB1/AMPK/Nrf2 signaling. The protection of ERS against APAP-triggered toxicity in AML-12 cells was subsequently abolished. As expression of LKB1 was knocked down, ERS still upregulated Sirt1 but failed to activate AMPK/Nrf2 cascade or suppress cytotoxicity provoked by APAP. Results of in vivo experiments showed that ERS attenuated APAP-caused hepatocyte apoptosis and ferroptosis and improved liver injury and inflammation. Consistently, ERS boosted Sirt1 expression, increased phosphorylations of LKB1 and AMPK, and promoted Nrf2 nuclear translocation in the livers of APAP-intoxicated mice. Hepatic transcriptions of HO-1 and GCLC, which are downstream antioxidant genes of Nrf2, were also significantly increased in response to ERS. Our results collectively indicated that ERS effectively attenuates APAP-induced liver injury by activating LKB1/AMPK/Nrf2 cascade. Upregulated expression of Sirt1 plays a crucial role in ERS-mediated activation of LKB1.

Alleviation of acetaminophen-induced liver failure using silibinin nanoliposomes: An in vivo study

BACKGROUND

Acetaminophen (Act) overdose is a known inducer of liver failure in both children and adults. Cell annihilation ensues following acetaminophen overdose and its toxic metabolites by depleting cellular GSH storage and increasing ROS levels. Silymarin extract and its major compound silibinin (SLB) possess robust antioxidant properties by inducing ROS elimination; however, low bioavailability and rapid metabolism limit their applications. Herein, we aimed at using SLB liposomes to combat acetaminophen-induced acute liver toxicity.

METHODS

We have developed a SLB-lipid complex to improve SLB loading efficiency within nanoliposome by using the lipid film method. Liposomes were characterized by using DLS and TEM analysis, and the release pattern, and toxicity profile on the normal cells as well as histopathological and serum analysis were investigated to reveal relevant enzyme activities in an animal model.

RESULTS

Data demonstrated that negatively-charged SLB liposomes of 115 nm had homogeneous spherical morphology, and entrapped a considerable quantity of SLB of almost 40%. Liposomes shows a favorable release pattern and were not toxic against NIH3T3 mouse fibroblast cells. The animal study revealed that treatment of mice with SLB nanoliposomes could significantly preserve liver function as revealed by the reduced levels of ALT and AST hepatic enzymes as well as ALP in the serum. Our data indicated that intraperitoneal administration of SLB Lip could significantly reduce ALT enzyme levels (p < 0.05) compared to N-acetylcysteine, while i.v administration resulted in no significant difference compared to control animals with no treatment.

CONCLUSION

The results of this study support the significant hepatoprotective effect of SLB nanoliposomes against acetaminophen-induced toxicity depending on the route of administration.

Insight into the negative effect and lipid profile alterations in liver of mice exposed to methylimidazolium ionic liquids, a novel "green" solvent

Background

Ionic liquids (ILs) have been recognized as potential environmentally friendly solvents; however, their potential toxicity to living organisms warrants thorough investigation, particularly for novel-generation ILs in mammalian models.

Methods

In this study, we examined the hepatic effects and disruption of lipid metabolism in mice exposed to 1-heptyl-3-methylimidazolium chloride (C7[MIM]Cl), a novel ILs. After four weeks of oral administration at different dosages (2.38, 5.95, and 11.9 mg/kg b.w.), we conducted clinical chemistry analysis and histopathological examination of the liver to assess biochemical and structural changes.

Results

The low-dose C7[MIM]Cl group exhibited a significant increase in alanine aminotransferase (ALT) levels, while aspartate aminotransferase (AST) levels were elevated in both low-dose and high-dose groups without statistical significance. Histopathological examination showed inflammatory cell infiltration and red blood cell aggregation in the livers of mice exposed to C7[MIM]Cl, particularly in the high-dose group. Oxidative stress levels showed moderate changes in response to C7[MIM]Cl exposure. Notably, hepatic biochemical parameters revealed a dose-dependent increase in triglycerides (TG) levels with statistically significant differences compared to the control group (P ≤ 0.01). Targeted lipidomic analysis revealed notable alterations in liver lipids of mice exposed to C7[MIM]Cl, with lysophosphatidylethanolamine (18:0), phosphatidylcholines (18:0), and phosphatidylcholines (19:0) identified as critical lipids associated with C7[MIM]Cl exposure. Furthermore, metabolic pathway analyses demonstrated significant disturbances in the glycerophospholipid metabolic pathway.

Conclusion

These findings provide valuable insights into the hepatic effects of C7[MIM]Cl exposure and novel perspectives on the disruption of lipid metabolism underlying ILs toxicity.

Antioxidant, anti-inflammatory, hypoglycemic, and anti-hyperglycemic activity of chickpea protein hydrolysates evaluated in BALB-c mice

Chickpea (ICC3761) protein hydrolysates have shown high in vitro antioxidant activity (AoxA) and antidiabetic potential. The aim of this study was to evaluate the in vivo activities (i.e., antioxidant, anti-inflammatory, hypoglycemic, and anti-hyperglycemic) of chickpea albumin hydrolysates (CAH) obtained with alcalase and pepsin-pancreatin (fractions ≤ 10 kDa). The CAH were analyzed for degree of hydrolysis (DH), electrophoretic and chromatographic profiles, and in vitro AoxA (2,2'-azino-bis(3-ethylbenzothiazolin)-6-sulfonic acid [ABTS], 2,2-diphenyl-1-pycrilhydrazyl [DPPH]). They were also evaluated for AoxA, anti-inflammatory and hypo- and anti-hyperglycemic activities in BALB-c mice. The DH was 20% for the alcalase CAH and 50% for the pepsin-pancreatin CAH, while the AoxA by ABTS (1 mg/mL) was 64.8% and 64.9% and by DPPH (5 mg/mL) was 48.0% and 31.1%. In the in vivo AoxA assay, mice of non-damaged control and those treated with both CAH showed similar alkaline phosphatase values, control and pepsin-pancreatin treated groups had similar malondialdehyde levels, while treated and non-damaged control groups had higher glutathione levels than the damaged control. Liver histopathology revealed that the pepsin-pancreatin CAH mitigated most of the pathological changes associated with the induced oxidative damage. Both CAH (2 mg/ear) reduced croton oil-induced ear edema in mice. The α-glucosidase inhibition of CAH (100 mg/mL) was 31.1% (alcalase) and 52.4% (pepsin-pancreatin). Mice treated with alcalase CAH (100 mg/mL) and glibenclamide exhibited similar hypoglycemic activities, whereas only those treated with the pepsin-pancreatin CAH (200 mg/kg body weight) showed anti-hyperglycemic activity. The results indicate that CAH can be used as a source of bioactive peptides with antioxidant, anti-inflammatory, hypoglycemic, and anti-hyperglycemic activities.

A Comparative GC/MS Analysis of Citrus Essential Oils: Unveiling the Potential Benefits of Herb-Drug Interactions in Preventing Paracetamol-Induced Hepatotoxicity

Our study aimed to test the potential of Citrus oils in protecting against paracetamol (PAR)-induced hepatotoxicity. The essential oils of Pineapple sweet orange (OO), Murcott mandarin (MO), Red grapefruit (GO), and Oval kumquat (KO) were investigated using gas chromatography coupled with mass spectrometry (GC/MS). Twenty-seven compounds were identified, with monoterpene hydrocarbons being abundant class. d-Limonene had the highest percentage (92.98 %, 92.82 %, 89.75 %, and 94.46 % in OO, MO, GO, and KO, respectively). Hierarchical cluster analysis (HCA) and principal components analysis (PCA) revealed that octanal, linalool, germacrene D, and d-limonene were the principal discriminatory metabolites that segregated the samples into three distinct clusters. In vitro antioxidant capacities were ranged from 1.2-12.27, 1.79-5.91, and 235.05-585.28 μM Trolox eq/mg oil for 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic (ABTS), ferric-reducing antioxidant power (FRAP), and oxygen radical absorbance capacity (ORAC), respectively. In vivo, citrus oils exhibited a significant reduction in alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and nitric oxide (NO). Additionally, there was an increase in glutathione reductase (GSH), and the liver architecture was nearly normal. Molecular docking revealed that d-limonene exhibited a good inhibitory interaction with cytochrome P450 (CYP450) isoforms 1A2, 3A4, and 2E1, with binding energies of -6.17, -4.51, and -5.61 kcal/mol, respectively.

Advances in the understanding of acetaminophen toxicity mechanisms: a clinical toxicology perspective

INTRODUCTION

Acetaminophen (paracetamol) is a commonly used analgesic and antipyretic agent, which is safe in therapeutic doses. Acetaminophen poisoning due to self-harm or repeated supratherapeutic ingestion is a common cause of acute liver injury. Acetylcysteine has been a mainstay of treatment for acetaminophen poisoning for decades and is efficacious if administered early. However, treatment failures occur if administered late, in 'massive' overdoses or in high-risk patients.

AREAS COVERED

This review provides an overview of the mechanisms of toxicity of acetaminophen poisoning (metabolic and oxidative phase) and how this relates to the assessment and treatment of the acetaminophen poisoned patient. The review focuses on how these advances offer further insight into the utility of novel biomarkers and the role of proposed adjunct treatments.

EXPERT OPINION

Advances in our understanding of acetaminophen toxicity have allowed the development of novel biomarkers and a better understanding of how adjunct treatments may prevent acetaminophen toxicity. Newly proposed adjunct treatments like fomepizole are being increasingly used without robust clinical trials. Novel biomarkers (not yet clinically available) may provide better assessment of these newly proposed adjunct treatments, particularly in clinical trials. These advances in our understanding of acetaminophen toxicity and liver injury hold promise for improved diagnosis and treatment.