Intravenous acetylcysteine for the treatment of acetaminophen overdose

Indole-3-carboxaldehyde alleviates acetaminophen-induced liver injury via inhibition of oxidative stress and apoptosis

Drug-induced liver injury (DILI) occurs frequently and can be life-threatening. Increasing researches suggest that acetaminophen (APAP) overdose is a leading cause of drug-induced liver injury. Indole-3-carboxaldehyde (I3A) alleviates hepatic inflammation, fibrosis and atherosclerosis, suggesting a potential role in different disease development. However, the question of whether and how I3A protects against acetaminophen-induced liver injury remains unanswered. In this study, we demonstrated that I3A treatment effectively mitigates acetaminophen-induced liver injury. Serum alanine/aspartate aminotransferases (ALT/AST), liver malondialdehyde (MDA) activity, liver glutathione (GSH), and superoxide dismutase (SOD) levels confirmed the protective effect of I3A against APAP-induced liver injury. Liver histological examination provided further evidence of I3A-induced protection. Mechanistically, I3A reduced the expression of apoptosis-related factors and oxidative stress, alleviating disease symptoms. Finally, I3A treatment improved survival in mice receiving a lethal dose of APAP. In conclusion, our study demonstrates that I3A modulates hepatotoxicity and can be used as a potential therapeutic agent for DILI.

Goji Ferment Ameliorated Acetaminophen-Induced Liver Injury in vitro and in vivo

This study aimed to investigate the hepatoprotective effects of lyophilized powder of goji ferment (LPGF) against acetaminophen (APAP)-induced hepatic damage in Hep3B cells and in mice. Eleven strains of lactic acid bacteria (LAB) were selected and their hepatoprotection against APAP-induced cellular damage in Hep3B cell line was evaluated. Four strains of LAB, including BCRC11652 (Leuconostoc mesenteroides subsp. mesenteroides), BCRC14619 (Lactobacillus gasseri), KODA-1 (Pediococcus acidilactici), and KODA-2 (Limosilactobacillus fermentum), have hepatoprotective potential against APAP in vitro. Goji significantly stimulated the growth of individual and combined strains of LAB and the optimal fermented condition was the treatment of goji at 10% (w/w) for 24 h. The prepared lyophilized powder of goji ferment (LPGF) containing fifteen combinations of LAB strains was used to explore their hepatoprotection in vitro. LPGF containing all combinations of LAB strains, except for KODA-2, significantly restored APAP-reduced cell viability and improved APAP-increased cellular levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). In mice model, LPGF containing BCRC11652, BCRC14619, and KODA-2 was chosen to evaluate its hepatoprotection against APAP-induced liver injury. LPGF at diverse doses have a tendency but no significant improvement on APAP-reduced body weight gain and liver weight. LPGF significantly decreased APAP-increased serum ALT and AST levels in a dose-dependent manner. At the end of experiment, LPGF significantly and dose-dependently reversed APAP-reduced activities of GSH and antioxidant enzymes, including glutathione peroxidase, superoxide dismutase, and catalase in hepatic tissue. Overall, LPGF was demonstrated to exhibit hepatoprotection against APAP-induced liver injury in vitro and in vivo.

New-onset and relapsed liver diseases following COVID-19 vaccination: a systematic review

BACKGROUND

Liver diseases post-COVID-19 vaccination is extremely rare but can occur. A growing body of evidence has indicated that portal vein thrombosis, autoimmune hepatitis, raised liver enzymes and liver injuries, etc., may be potential consequence of COVID-19 vaccines.

OBJECTIVES

To describe the results of a systematic review for new-onset and relapsed liver disease following COVID-19 vaccination.

METHODS

For this systematic review, we searched Proquest, Medline, Embase, PubMed, CINAHL, Wiley online library, Scopus and Nature through the Preferred Reporting Items for Systematic Reviews and Meta Analyses PRISMA guideline for studies on the incidence of new onset or relapsed liver diseases post-COVID-19 vaccination, published from December 1, 2020 to July 31, 2022, with English language restriction.

RESULTS

Two hundred seventy-five cases from one hundred and eighteen articles were included in the qualitative synthesis of this systematic review. Autoimmune hepatitis (138 cases) was the most frequent pathology observed post-COVID-19 vaccination, followed by portal vein thrombosis (52 cases), raised liver enzymes (26 cases) and liver injury (21 cases). Other cases include splanchnic vein thrombosis, acute cellular rejection of the liver, jaundice, hepatomegaly, acute hepatic failure and hepatic porphyria. Mortality was reported in any of the included cases for acute hepatic failure (n = 4, 50%), portal vein thrombosis (n = 25, 48.1%), splanchnic vein thrombosis (n = 6, 42.8%), jaundice (n = 1, 12.5%), raised liver enzymes (n = 2, 7.7%), and autoimmune hepatitis (n = 3, 2.2%). Most patients were easily treated without any serious complications, recovered and did not require long-term hepatic therapy.

CONCLUSION

Reported evidence of liver diseases post-COIVD-19 vaccination should not discourage vaccination against this worldwide pandemic. The number of reported cases is relatively very small in relation to the hundreds of millions of vaccinations that have occurred and the protective benefits offered by COVID-19 vaccination far outweigh the risks.

Application of Melatonin with N-Acetylcysteine Exceeds Traditional Treatment for Acetaminophen-Induced Hepatotoxicity

Acetaminophen (APAP) overdose is one of the leading causes of acute liver damage. Given N-acetylcysteine (NAC) and melatonin (MLT) both have an attenuated value for APAP-induced liver toxification, where an optimized integrated treatment has not been well deciphered. Here, by giving a single dose of APAP (500 mg/kg) to wild-type male mice, combined with a single dose of 500 mg/kg NAC or 100 mg/kg MLT separately as the therapeutic method, this study aimed to investigate the effects of NAC and melatonin (MLT) alone or combined on acetaminophen (APAP)-induced liver injury. In this study, NAC and MLT both partially have an alleviated function in APAP-challenged liver injury. However, MLT's add-on role strengthens the hepatoprotective effect of NAC on APAP-induced liver damage and resolute the inflammatory infiltration. Meanwhile, the combination of two reagents attenuates the decreased glutathione (GSH) and activation of the p38/JNK pathway. The combination of MLT and NAC can further ameliorate APAP-induced liver injury, which provides a novel strategy for drug-induced liver injury (DILI).

Ficus exasperata Attenuates Acetaminophen-Induced Hepatic Damage via NF-κB Signaling Mechanism in Experimental Rat Model

Ficus exasperata has been used to treat ulcer, diabetes, fever, and a variety of stress-related disorders. Acetaminophen (APAP) overdose is the most common cause of drug-induced acute liver injury. In this study, we evaluated the hepatoprotective effect and antioxidant capacity of ethanolic extract of F. exasperata (EFE) on acetaminophen-induced hepatotoxicity in albino rats. Rats were pretreated with EFE (150, 250, 500 mg/kg) and thereafter received 250 mg/kg APA intraperitoneally (i.p.). The normal control group received distilled water, while the negative control group received 250 mg/kg APAP, respectively. Hepatotoxicity and oxidative stress-antioxidant parameters were then assessed. Flavonoids, saponins, steroids, and glycosides, but not phenolics were detected by EFE phytochemical analysis. No mortality was recorded on acute exposure of rats to varying concentrations of APAP after 24 h; however, a dose-dependent increase in severity of convulsion, urination, and hyperactivity was observed. APAP overdose induced high AST, ALT, ALP, and total bilirubin levels in the serum, invoked lipid peroxidation, depleted GSH, decreased CAT, SOD, and GST levels, respectively. Nitric oxide (NO) level, myeloperoxidase activity, TNF-α, IL-1β, NF-κB, COX-2, MCP-1, and IL-6 were also increased. Importantly, pretreatment of rats with EFE before acetaminophen ameliorated and restored cellular antioxidant status to levels comparable to the control group. Our results show and suggest the hepatoprotective effect of F. exasperata and its ability to modulate cellular antioxidant status supports its use in traditional medicine and renders it safe in treating an oxidative stress-induced hepatic injury.

Comparing N-acetylcysteine and 4-methylpyrazole as antidotes for acetaminophen overdose

Acetaminophen (APAP) overdose can cause hepatotoxicity and even liver failure. N-acetylcysteine (NAC) is still the only FDA-approved antidote against APAP overdose 40 years after its introduction. The standard oral or intravenous dosing regimen of NAC is highly effective for patients with moderate overdoses who present within 8 h of APAP ingestion. However, for late-presenting patients or after ingestion of very large overdoses, the efficacy of NAC is diminished. Thus, additional antidotes with an extended therapeutic window may be needed for these patients. Fomepizole (4-methylpyrazole), a clinically approved antidote against methanol and ethylene glycol poisoning, recently emerged as a promising candidate. In animal studies, fomepizole effectively prevented APAP-induced liver injury by inhibiting Cyp2E1 when treated early, and by inhibiting c-jun N-terminal kinase (JNK) and oxidant stress when treated after the metabolism phase. In addition, fomepizole treatment, unlike NAC, prevented APAP-induced kidney damage and promoted hepatic regeneration in mice. These mechanisms of protection (inhibition of Cyp2E1 and JNK) and an extended efficacy compared to NAC could be verified in primary human hepatocytes. Furthermore, the formation of oxidative metabolites was eliminated in healthy volunteers using the established treatment protocol for fomepizole in toxic alcohol and ethylene glycol poisoning. These mechanistic findings, together with the excellent safety profile after methanol and ethylene glycol poisoning and after an APAP overdose, suggest that fomepizole may be a promising antidote against APAP overdose that could be useful as adjunct treatment to NAC. Clinical trials to support this hypothesis are warranted.

Ameliorating effects of N-acetyl cysteine against early liver damage of radioiodine in rats

OBJECTIVE

The present study was aimed to explore the potential ameliorating effects of N-acetyl cysteine (NAC) against radioiodine (RAI)-induced early liver damage.

METHODS

Thirty Wistar Albino male rats were arbitrarily allocated into three groups each containing 10 rats: the control group (group 1); the RAI group (group 2), oral 111 MBq/kg radioiodine was administered to rats; the RAI + NAC group (group 3), 150 mg/kg/day intraperitoneal NAC treatment was initiated 3 days prior to the RAI administration and continued for 10 days. Liver samples were obtained 24 h after the last dose of NAC therapy for biochemical and histopathologic evaluation.

RESULTS

In the RAI + NAC group, the histopathologic damage was found significantly less than in the RAI group for whole parameters except inflammatory cell infiltration (P < 0.05). Unlike the RAI group which had marked histopathologic damage, the RAI + NAC group had only mild histologic activity index scores with no granuloma formation observed. Oxidative stress parameters were demonstrated that the NAC treatment significantly decreased the tissue malondialdehyde (MDA) and catalase levels and increased the total sulfhydryl (total sulfhydryl) levels when compared to the RAI group (P < 0.01).

CONCLUSION

The outcomes of the study exhibited that the NAC treatment improved RAI-induced early liver damage. This improving effect considered to be caused by its antioxidant, anti-inflammatory, and likely vasodilator properties of NAC. Having advantages such as inexpensive, easy access, and tolerability, the NAC can be used as a radioprotective agent, especially in patients with liver diseases and requiring RAI treatment.

An ultrasensitive electrochemical sensor for the detection of acetaminophen via a three-dimensional hierarchical nanoporous gold wire electrode

Acetaminophen is one of the most commonly used non-steroidal anti-inflammatory drugs worldwide. However, due to the increasing popularity of this drug, overdosing and the contamination of ambient waterways have emerged as major issues. Here, we report on a reliable, ultrasensitive, and easy-to-use sensor for the electrochemical detection of acetaminophen. This sensor employs a gold wire electrode with a unique three-dimensional hierachical nanoporous structure, fabricated using a dissolution, disproportion and deposition procedure. In consideration of optimal sensitivity and reproducibility, the most suitable nanoporous gold electrode was employed for the detection of acetamiophen among a set of nanoporous electrodes made under different reaction times. It was found that the pore size, film thickness, and electrochemically active surface area (ECSA) played major roles in the fouling resistance of the developed sensor. The ECSA of the selected sensor was increased by 15.8 times after the post-treatment. The 3D nanoporous electrode demonstrated excellent performance for the detection of acetaminophen with a low detection limit of 3.37 nM, and a strong anti-interference capability. The developed nanoporous Au electrode proved effective for the detection of acetaminophen in real sheep serum, which confirmed its promising application for medical diagnostics and pollutant surveilliance in source waters.

Massive acetaminophen overdose with metabolic acidosis refractory to N-acetylcysteine, fomepizole, and renal replacement therapy

Massive Acetaminophen (N-acetyl-p-aminophenol; APAP) overdose is a common presentation to emergency departments around the world. While N-acetylcysteine (NAC) remains the cornerstone of treatment for APAP overdose, extracorporeal treatment, in the form of renal replacement therapy with intermittent hemodialysis (IHD) or continuous renal replacement therapy (CRRT) may provide benefit in cases associated with altered mental status and metabolic acidosis. One treatment with IHD is typically sufficient for resolution of acidosis and global improvement clinically. We describe a case of massive APAP overdose presenting with altered mental status and lactic acidosis, refractory to multiple treatments of IHD as well as CRRT and high-dose NAC along with fomepizole. Despite these interventions, fulminant liver failure progressed with cerebral edema, coagulopathy and death. This is the first description of a fatal acetaminophen ingestion refractory to both IHD and prolonged CRRT. This case highlights the need for further investigation in the management of massive APAP overdose, including optimal method and timing of renal replacement therapy.

(+)-Clausenamide protects against drug-induced liver injury by inhibiting hepatocyte ferroptosis

Drug-induced liver injury is the major cause of acute liver failure. However, the underlying mechanisms seem to be multifaceted and remain poorly understood, resulting in few effective therapies. Here, we report a novel mechanism that contributes to acetaminophen-induced hepatotoxicity through the induction of ferroptosis, a distinctive form of programmed cell death. We subsequently identified therapies protective against acetaminophen-induced liver damage and found that (+)-clausenamide ((+)-CLA), an active alkaloid isolated from the leaves of Clausena lansium (Lour.) Skeels, inhibited acetaminophen-induced hepatocyte ferroptosis both in vivo and in vitro. Consistently, (+)-CLA significantly alleviated acetaminophen-induced or erastin-induced hepatic pathological damages, hepatic dysfunctions and excessive production of lipid peroxidation both in cultured hepatic cell lines and mouse liver. Furthermore, treatment with (+)-CLA reduced the mRNA level of prostaglandin endoperoxide synthase 2 while it increased the protein level of glutathione peroxidase 4 in hepatocytes and mouse liver, confirming that the inhibition of ferroptosis contributes to the protective effect of (+)-CLA on drug-induced liver damage. We further revealed that (+)-CLA specifically reacted with the Cys-151 residue of Keap1, which blocked Nrf2 ubiquitylation and resulted in an increased Nrf2 stability, thereby leading to the activation of the Keap1–Nrf2 pathway to prevent drug-induced hepatocyte ferroptosis. Our studies illustrate the innovative mechanisms of acetaminophen-induced liver damage and present a novel intervention strategy to treat drug overdose by using (+)-CLA.

Rapid SERS Detection of Thiol-Containing Natural Products in Culturing Complex

Thiol-containing natural products possess a wide range of bioactivities. The burst of synthetic biology technology facilitates the discovery of new thiol-containing active ingredients. Herein, we report a sensitive, quick, and robust surface-enhanced Raman scattering technology for specific and multiplex detection of thiol-containing compounds without purification requirements and also indicating the thiols with different chemical environments. Using this platform, we successfully demonstrated the simultaneous detection of thiol-containing compounds from as low as 1 μM of analytes spiked in complex culture matrices.

Limonin ameliorates acetaminophen-induced hepatotoxicity by activating Nrf2 antioxidative pathway and inhibiting NF-κB inflammatory response via upregulating Sirt1

BACKGROUND

Limonin, a bioactive compound from citrus plants, exerts antioxidant activities, however its therapeutic potential in acetaminophen (APAP)-induced hepatotoxicity remains unclear.

PURPOSE

Our study aims to investigate the protective effect of limonin on APAP-induced hepatotoxicity and illuminate the underlying mechanisms.

STUDY

design In vitro, we chose L-02 cells to establish in vitro APAP-induced liver injury model. L-02 cells were treated with APAP (7.5 mM) for 24 h after pre-incubation with limonin (10, 25, 50 μM) or NAC (250 μM) for 2 h. In vivo, we used C57BL/6 mice as an in vivo APAP-induced liver injury model. C57BL/6 mice with pre-treatment of limonin (40, 80 mg/kg) or NAC (150 mg/kg) for 1 h, were given with a single dose of APAP (300 mg/kg).

METHODS

After pre-incubation with limonin (10, 25, 50 μM) for 2 h, L-02 cells were treated with APAP (7.5 mM) for 24 h.The experiments in vitro included MTT assay, Annexin V/PI staining, measurement of reactive oxygen species (ROS), quantitative real-time PCR analysis, Western blot analysis, immunofluorescence microscopy and analysis of LDH activity. Transfection of Nrf2 or Sirt1 siRNA was also conducted in vitro. In vivo, C57BL/6 mice with pre-treatment of limonin (40, 80 mg/kg) or NAC (150 mg/kg) for 1 h, were given with a single dose of APAP (300 mg/kg). Mice were sacrificed at 4, 12 h after APAP poisoning, and analysis of ALT and AST in serum, GSH level in liver tissues, liver histological observation and immunohistochemistry were performed.

RESULTS

Limonin increased the cell viability and alleviated APAP-induced apoptosis in hepatocytes. Limonin also inhibited APAP-induced mitochondrial-mediated apoptosis by decreasing the ratio of Bax/Bcl-2, recovery of mitochondrial membrane potential (MMP), inhibiting ROS production and cleavage of caspase-3 in L-02 cells. Moreover, limonin induced activation of Nrf2 and increased protein expression and mRNA levels of its downstream targets, including HO-1, NQO1 and GCLC/GCLM. The inhibition of limonin on apoptosis and promotion on Nrf2 antioxidative pathway were lessened after the application of Nrf2 siRNA. In addition, limonin inhibited NF-κB transcriptional activation, NF-κB-regulated genes and protein expression of inflammatory related proteins iNOS and COX2. Furthermore, limonin increased the protein expression of Sirt1. Sirt1 siRNA transfection confirmed that limonin activated Nrf2 antioxidative pathway and inhibited NF-κB inflammatory response by upregulating Sirt1. Finally, we established APAP-induced liver injury in vivo and demonstrated that limonin alleviated APAP-induced hepatotoxicity by activating Nrf2 antioxidative signals and inhibiting NF-κB inflammatory response via upregulating Sirt1.

CONCLUSION

In summary, this study documented that limonin mitigated APAP-induced hepatotoxicity by activating Nrf2 antioxidative pathway and inhibiting NF-κB inflammatory response via upregulating Sirt1, and demonstrated that limonin had therapeutic promise in APAP-induced liver injury.

The impact of alcohol use disorders on pulmonary immune cell inflammatory responses to Streptococcus pneumoniae

Community-acquired pneumonia due to Streptococcus pneumoniae occurs commonly in alcohol use disorders (AUDs). Pneumonia in the AUD patient is associated with poorer outcomes, and specific therapies to mitigate disease severity in these patients do not exist. Numerous investigations have attributed increased severity of pneumonia in AUDs to aberrant function of the alveolar macrophage (AM), a lung immune cell critical in host defense initiation. No studies have examined the response of human AMs to S. pneumoniae in AUDs. We hypothesized that the inflammatory mediators released by AMs after S. pneumoniae stimulation would differ quantitatively in individuals with AUDs compared to non-AUD participants. We further postulated that AM inflammatory mediators would be diminished after exposure to the antioxidant, N-acetylcysteine (NAC). For comparison, responses of peripheral blood mononuclear cells (PBMCs) to pneumococcal protein were also examined. Otherwise healthy participants with AUDs and smoking-matched controls underwent bronchoalveolar lavage and peripheral blood sampling to obtain AMs and PBMCs, respectively. Freshly collected cells were cultured with increasing doses of heat-killed S. pneumoniae protein, with and without exposure to N-acetylcysteine. Cell culture supernatants were collected, and inflammatory mediators were measured, including interferon (IFN)-γ, interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. IFN-γ and IL-6 were significantly higher in unstimulated AM cell culture supernatants from subjects with AUDs. After stimulation with pneumococcal protein, a dose-response and time-dependent increase in pro-inflammatory cytokine production by both AMs and PBMCs was also observed; differences were not observed between AUD and non-AUD subjects. Addition of NAC to pneumococcal-stimulated AMs and PBMCs was generally associated with diminished cytokine production, with the exception of IL-1β that was elevated in AM culture supernatants from subjects with AUDs. Our observations suggest that AUDs contribute to basal alterations in AM pro-inflammatory cytokine elaboration, but did not support consistent differences in pneumococcal-stimulated AM or PBMC inflammatory mediator secretion that were referable to AUDs.

Designing around Structural Alerts in Drug Discovery

Cumulative research over several decades has implicated the involvement of reactive metabolites in many idiosyncratic adverse drug reactions (IADRs). Consequently, "avoidance" strategies have been inserted into drug discovery paradigms, which include the exclusion of structural alerts and possible termination of reactive metabolite-positive compounds. Several noteworthy examples where reactive metabolite-related liabilities have been resolved through structure-metabolism studies are presented herein. Considerable progress has also been made in addressing the limitations of the avoidance strategy and further refining the process of managing reactive metabolite issues in drug development. These efforts primarily stemmed from the observation that numerous drugs, which contain structural alerts and/or form reactive metabolites, are devoid of ADRs. The Perspective also dwells into an analysis of the structural alert/reactive metabolite concept with a discussion of risk mitigation tactics to support the progression of reactive metabolite-positive drug candidates.

Beneficial Effects of N-Acetyl-L-cysteine or Taurine Pre- or Post-treatments in the Heart, Spleen, Lung, and Testis of Hexavalent Chromium-Exposed Mice

Hexavalent chromium[Cr(VI)] compounds may induce toxic effects, possibly via reactive intermediates and radicals formed during Cr(VI) reduction. In this study, we probed the possible effects of N-acetyl-L-cysteine (NAC) and taurine pre- or post-treatments on Cr(VI)-induced changes in lipid peroxidation and nonprotein thiols (NPSH) in mice heart, lung, spleen, and testis tissues. The mice were randomly assigned to six groups, consisting of control, Cr(VI)-exposed (20 mg Cr/kg, intraperitoneal ,ip), NAC (200 mg/kg, ip) as pre-treatment and post-treatment, and taurine (1 g/kg, ip) pre-treatment and post-treatment groups. Lipid peroxidation and NPSH levels were determined and the results were compared with regard to tissue- and antioxidant-specific basis. Exposure to Cr(VI) significantly increased lipid peroxidation in all tissues as compared to the control (p < 0.05); and consistent with this data, NPSH levels were significantly decreased (p < 0.05). Notably, administration of NAC and taurine, either before or after Cr(VI) exposure, was able to ameliorate the lipid peroxidation (p < 0.05) in all tissues. In the case of NPSH content, while the decline could be alleviated by both NAC and taurine pre- and post-treatments in the spleen, diverging results were obtained in other tissues. The effects of Cr(VI) on the lung thiols were abolished by pre-treatment with NAC and taurine; however, post-treatments could not exert significant effect. While thiol depletion in the heart was totally replenished by NAC and taurine administrations, NAC pre-treatment was partially more effective than post-treatment. In contrast with lipid peroxidation data, NAC treatment could not provide a statistically significant beneficial effect on NPSH content of the testis, whereas the effect in this tissue by taurine was profound. Thus, these data highlight the importance of tissue-specific factors and the critical role of administration time. Overall, our data suggest that NAC and taurine may have potential in prevention of Cr(VI)-induced toxicity in the heart, lung, spleen, and testis tissues.

The Role of Acetyl Cysteine in Cocaethylene (Non-Acetaminophen) Acute Liver Failure

Background

Acute liver failure can result from acetaminophen overdose, viral infection, toxins, and other disease conditions. Liver transplant is available in limited fashion and the criteria are strict as to who should get an available liver. N- Acetyl Cysteine (NAC) has been used in non-acetaminophen induced liver failure with success. Here we report a case of acute liver failure from cocaethylene that was reversed with NAC along with other medical therapy.

Case Presentation

A 50-year-old female patient presented to the Emergency Department (ED) with a two-day history of coffee ground vomiting and hematemesis. She reported occasional substance abuse and heavy alcoholism. She reported shortness of breath and chest pain from the recurrent forceful vomiting. The rest of the review of systems was unremarkable except a fall from intoxication. Physical examination revealed anicteric conjunctiva and nontender abdomen and her vital signs were within normal limits. Initial blood work revealed acute liver and renal failure. The patient was started with general medical management and liver transplant service rejected the case due to active substance abuse. She underwent brief hemodialysis and was started on NAC. Over the course of her hospital stay her liver function and kidney function improved significantly and patient was discharged to home.

Conclusion

In cases where liver transplant is not an option for various reasons including active substance abuse, a trial of N-Acetyl Cysteine may be beneficial and should be considered in the Emergency Department.

Nrf2-mediated liver protection by esculentoside A against acetaminophen toxicity through the AMPK/Akt/GSK3β pathway

Acetaminophen (APAP) overdose accounts for the majority of acute liver failure cases, and oxidative stress plays a key role in its toxic effects. Esculentoside A (EsA) has anti-oxidant activities, but its therapeutic potential for APAP hepatotoxicity remains unknown. This study aimed to assess the protective effects and mechanism of EsA against APAP-induced hepatotoxicity in vitro and in vivo. In vitro, EsA treatment inhibited APAP- or H2O2-induced cytotoxicity, H2O2 and O2- production, glutathione (GSH) depletion and apoptosis dependent on nuclear factor erythroid-2-related factor 2 (Nrf2) activation in HepG2 cells. Moreover, EsA significantly increased the phosphorylation of AMP-activated protein kinase (AMPK) and serine/threonine kinase (Akt), as well as glycogen synthase kinase 3 beta (GSK-3β) inhibitory phosphorylation at Ser9. Furthermore, an AMPK inhibitor (compound c) abolished the effects of EsA on AKT phosphorylation, GSK-3β inactivation, Nrf2 nuclear translocation and cytoprotection. With regard to APAP-induced acute liver injury, EsA attenuated the APAP-stimulated increases in the serum ALT and AST levels, as well as centrilobular necrosis and GSH depletion in the mice. In addition, it decreased the GSSG level, GSSG-to-GSH ratio, and the phosphorylation and mitochondrial translocation of c-Jun N-terminal kinase (JNK). Further, the protective potential of EsA against mitochondrial dysfunction was exhibited not only by inhibiting Bax mitochondrial translocation and the release of mitochondrial inter-membrane proteins, such as apoptosis-inducing factor (AIF), but also by activating Nrf2/HO-1. Collectively, our findings suggest that EsA has protective potential against APAP toxicity by potentiating the Nrf2-regulated survival mechanism through the AMPK/Akt/GSK3β pathway.

Effervescent N-Acetylcysteine Tablets versus Oral Solution N-Acetylcysteine in Fasting Healthy Adults: An Open-Label, Randomized, Single-Dose, Crossover, Relative Bioavailability Study

BACKGROUND

Oral solution N-acetylcysteine (NAC) is an antidote for acetaminophen overdose, but its unpleasant taste and aroma can impede delivery even after the coadministration of antiemetic medications. Flavored effervescent NAC tablets dissolved in water might be a more palatable formulation than oral solution NAC diluted with soft drink.

OBJECTIVES

To evaluate the relative bioavailability of these 2 formulations and assess subjective preferences between them.

METHODS

Thirty healthy adult volunteers (mean [SD] = 35.2 [9.14] years) were enrolled in this open-label, randomized, single-dose, crossover study, with a 7-day washout period. Volunteers were randomized to receive 11 g effervescent test formulation or the reference product under fasting conditions, after which 19 serial blood samples were collected over 48 hours. Total plasma NAC concentrations were evaluated by LC-MS, and pharmacokinetic parameters were calculated. The 2 formulations were considered bioequivalent if the 90% CIs of log-transformed ratios of pharmacokinetic parameters were within the predetermined bioequivalence range (80%-125%) established by the US Food and Drug Administration. Within 15 minutes of dosing, subjects were also asked to rank formulation attributes on a 5-point hedonic scale, with mean group differences analyzed by Wilcoxon signed rank test. Safety-profile assessment included treatment-emergent adverse events, physical examination, chemistry, and hematology parameters.

RESULTS

The concentration-versus-time profiles were similar for the 2 formulations, with mean Cmax of 26.5 μg/mL for effervescent NAC tablets and 28.4 μg/mL for oral solution NAC. The 90% CIs for the pharmacokinetic parameters met the criteria for concluding bioequivalence, and subjects preferred effervescent NAC tablets in terms of taste (P = 0.0247), flavor (P = 0.0082), texture (P = 0.009), and overall likeability (P = 0.0012), but there was no difference for smell (P = 0.0533). All treatment-emergent adverse events were mild, with no differences between the treatment groups.

CONCLUSIONS

Data from this study of a single dose of 11 g oral NAC demonstrated that effervescent NAC tablets and oral solution NAC met the regulatory criteria for bioequivalence in fasting healthy adult subjects. Effervescent NAC tablets appear to be a more palatable alternative for treatment of acetaminophen overdose. ClinicalTrials.gov identifier: NCT02723669. (Curr Ther Res Clin Exp. 2016; 83C:1-7) © 2016 Elsevier HS Journals, Inc.

Caffeic acid prevents acetaminophen-induced liver injury by activating the Keap1-Nrf2 antioxidative defense system

Acute liver failure induced by acetaminophen (APAP) overdose is the main cause of drug-induced liver injury (DILI). Caffeic acid (CA) is a phenolic compound from many natural products. This study aims to investigate the protective mechanism of CA in APAP-induced liver injury. The results of serum alanine/aspartate aminotransferases (ALT/AST), liver myeloperoxidase (MPO) activity, liver glutathione (GSH) and reactive oxygen species (ROS) levels demonstrated the protection of CA against APAP-induced liver injury. Liver histological observation provided further evidences of CA-induced protection. CA was found to reverse the APAP-induced decreased cell viability in human normal liver L-02 cells and HepG2 cells. CA also reduced the increased cellular ROS level induced by APAP in hepatocytes. The results of luciferase assay and Western-blot analysis showed that CA increased the transcriptional activation of nuclear factor erythroid 2-related factor 2 (Nrf2) in the presence of APAP. Nrf2 siRNA reduced the protection of CA against APAP-induced hepatotoxicity. CA also reversed the APAP-induced decreased mRNA and protein expression of heme oxygenase 1 (HO-1) and

NAD(P)H

quinone oxidoreductase 1(NQO1). In addition, HO-1 inhibitor zinc protoporphyrin (ZnPP) and NQO1 inhibitor diminutol (Dim) reduced the protection of CA against APAP-induced hepatotoxicity. CA also decreased the expression of kelch-like ECH-associated protein-1(Keap1). Molecular docking indicated the potential interacting of CA with Nrf2 binding site in the Keap1 protein. CA had little effect on the enzymatic activity of cytochrome P450 (CYP) 3A4 and CYP2E1 in vitro. In conclusion, we demonstrated that CA prevented APAP-induced hepatotoxicity by decreasing Keap1 expression, inhibiting binding of Keap1 to Nrf2, and thus activating Nrf2 and leading to increased expression of antioxidative signals including HO-1 and NQO1.

Global research productivity of N-acetylcysteine use in paracetamol overdose: A bibliometric analysis (1976-2012)

PURPOSE

The main objective of this study was to examine the publication pattern of N-acetylcysteine (NAC) research output for paracetamol overdose at the global level.

METHODS

Data were searched for documents that contained specific words regarding NAC and paracetamol as keywords in the title and/or abstract and/or keywords. Scientific output was evaluated based on a methodology developed and used in other bibliometric studies. Research productivity was adjusted to the national population and nominal gross domestic product per capita.

RESULTS

The criteria were met by 367 publications from 33 countries. The highest number of articles associated with the use of NAC in paracetamol overdose was from the United States of America (USA; 39.78%), followed by the United Kingdom (UK; 11.99%). After adjusting for economy and population power, USA (2.822), Iran (1.784) and UK (1.125) had the highest research productivity. The total number of citations at the time of data analysis (14 March 2014) was 8785 with an average of 23.9 citations per document and a median (interquartile range) of 6 (1-22). The h-index of the retrieved documents was 48. The highest h-index was 32 for USA, followed by 20 for UK. Furthermore, the highest number of collaborations with international authors for each country was held by USA with 11 countries, followed by Canada with 7 countries.

CONCLUSION

The amount of NAC-based research activity was low in some countries, and more effort is needed to bridge this gap and to promote better evaluation of NAC use worldwide. Our findings demonstrate that NAC use for paracetamol overdose remains a hot issue in scientific research and may have a larger audience compared with other toxicological aspects. Editors and authors in the field of toxicology might usefully promote the submission of work on NAC in future to improve their journal's impact.

Antidote removal during haemodialysis for massive acetaminophen overdose

CONTEXT

Haemodialysis is sometimes used for patients with massive acetaminophen overdose when signs of "mitochondrial paralysis" (lactic acidosis, altered mental status, hypothermia and hyperglycaemia) are present. The role of haemodialysis is debated, in part because the evidence base is weak and the endogenous clearance of acetaminophen is high. There is also concern because the antidote acetylcysteine is also dialyzable. We prospectively measured serum acetylcysteine concentrations during haemodialysis in three such cases.

CASE DETAILS

Three adults each presented comatose and acidemic 10 to ~18 h after ingesting > 1000mg/kg of acetaminophen. Two were hypothermic and hyperglycaemic. Serum lactate concentrations ranged from 7 mM to 12.5 mM. All three were intubated, and initial acetaminophen concentrations were as high as 5980 μM (900 μg/mL). An intravenous loading dose of 150 mg/kg acetylcysteine was initiated between 10.8 and ~18 h post ingestion, and additional doses were empirically administered during haemodialysis to compensate for possible antidote removal. A single run of 3-4 h of haemodialysis removed 10-20 g of acetaminophen (48-80% of remaining body burden), reduced serum acetaminophen concentrations by 56-84% (total clearance 3.4-7.8 mL/kg/min), accelerated native acetaminophen clearance (mean elimination half-life 580 min pre-dialysis, 120 min during and 340 min post-dialysis) and corrected acidemia. Extraction ratios of acetylcysteine across the dialysis circuit ranged from 73% to 87% (dialysance 3.0 to 5.3 mL/kg/min). All three patients recovered fully, and none developed coagulopathy or other signs of liver failure.

DISCUSSION

When massive acetaminophen ingestion is accompanied by coma and lactic acidosis, emergency haemodialysis can result in rapid biochemical improvement. As expected, haemodialysis more than doubles the clearance of both acetaminophen and acetylcysteine. Because acetylcysteine dosing is largely empirical, we recommend doubling the dose during haemodialysis, with an additional half-load when dialysis exceeds 6 h.

Cisplatin otoprotection using transtympanic L-N-acetylcysteine: a pilot randomized study in head and neck cancer patients

OBJECTIVES/HYPOTHESIS

To evaluate the feasibility and efficacy of transtympanic L-N-Acetylcysteine (L-NAC) administration in patients receiving cisplatin chemotherapy for head and neck cancer.

STUDY DESIGN

Prospective randomized nonblinded open-label clinical trial.

METHODS

Transtympanic 2% L-NAC was administered to one randomly selected ear with the other ear as control in each patient. Primary outcome parameter was the difference in the loss of pure tone averages (PTA) at 2, 4, and 8 kHz between the L-NAC and control ear at 1 to 2 months following chemotherapy.

RESULTS

Eleven patients completed the study, with two patients demonstrating significantly better hearing in the L-NAC treated ear (18.2%). However, for the overall group, the difference in hearing preservation did not reach significance. Two percent L-NAC administration was well tolerated in this patient population. There were no adverse effects associated with L-NAC.

CONCLUSION

Although the study did not demonstrate a significant benefit overall, transtympanic L-NAC was associated with significantly better hearing in two patients. Better delivery methods may improve the efficacy of this treatment. L-NAC remains a promising drug in preventing cisplatin-induced ototoxicity.

N-acetylcysteine induced quenching of red fluorescent oligonucleotide-stabilized silver nanoclusters and the application in pharmaceutical detection

In this work, we reported a new, simple and sensitive method for determination of N-acetylcysteine (NAC) based on quenching of the red fluorescence of oligonuleotide-protected silver nanoculsters (Ag NCs) with the quantum yield of 68.3±0.3%. This method was successfully used for the assay of NAC granules presenting a linear range from 100 nM to 1200 nM (LOD of 50 nM) with minimal interferences from potential coexisting substances. It is for the first time that quenching performance of the thiol-containing compound was found to follow a non-linear Stern-Volmer profile, indicative of a complicated quenching mechanism with static quenching dominating, in which DNA-template of Ag NCs was partly replaced by NAC, as elucidated by spectral investigations. This study extended the analytical application of silver nanoclusters as well as provided a more insightful understanding of the quenching mechanism of thiol-compounds on the fluorescence of Ag NCs.

Therapeutic effect of liposomal-N-acetylcysteine against acetaminophen-induced hepatotoxicity

BACKGROUND

Acetaminophen (APAP) is an antipyretic analgesic drug that when taken in overdose causes depletion of glutathione (GSH) and hepatotoxicity. N-acetylcysteine (NAC) is the antidote of choice for the treatment of APAP toxicity; however, due to its short-half-life repeated dosing of NAC is required.

PURPOSE

To determine whether a NAC-loaded liposomal formulation (Lipo-NAC) is more effective than the conventional NAC in protecting against acute APAP-induced hepatotoxicity.

METHODS

Male Sprague-Dawley rats were challenged with an intragastric dose of APAP (850 mg/kg b.wt.); 4 h later, animals were administered saline, NAC, Lipo-NAC or empty liposomes and sacrificed 24 h post-APAP treatment.

RESULTS

APAP administration resulted in hepatic injury as evidenced by increases in plasma bilirubin, alanine (AST) and aspartate (ALT) aminotransferase levels and tissue levels of lipid peroxidation and myeloperoxidase as well as decreases in hepatic levels of reduced GSH, GSH peroxidase and GSH reductase. Treatment of animals with Lipo-NAC was significantly more effective than free NAC in reducing APAP-induced hepatotoxicity. Histological evaluation showed that APAP caused periacinar hepatocellular apoptosis and/or necrosis of hepatocytes around the terminal hepatic venules which was reduced by NAC treatment, the degree of reduction being greater for Lipo-NAC.

CONCLUSION

These data suggest that administration of Lipo-NAC ameliorated the APAP-induced hepatotoxicity.

Prenatal tolerability of acetaminophen and other over-the-counter non-selective cyclooxygenase inhibitors

Over-the-counter cyclooxygenase inhibitors are used to relief fever and various types of acute pain like headache, toothache, earache, sore throat, as well as postoperative and menstrual ones. They are also major ingredients in cold and flu mixtures. Unlike well-known organ toxicological profile, their prenatal toxicity was not fully established. For a long time, acetaminophen was considered as a relatively safe antipyretic and analgesic drug during pregnancy. However, a new data indicate that it may increase the risk of cryptorchidism and asthma during childhood as well as preeclampsia, preterm birth, maternal phlebothrombosis and pulmonary embolism. Contrary to acetaminophen, non-selective cyclooxygenase inhibitors (non-steroidal anti-inflammatory drugs - NSAID; i.e., diclofenac, ibuprofen, naproxen) may induce intrauterine growth retardation, ductus arteriosus constriction with secondary persistent pulmonary hypertension, reduced fetal renal perfusion that led to oligohydramion, prolonged pregnancy as well as increase prevalence of intracranial bleeding in newborns. Furthermore, a higher risk of miscarriage, stillbirth and some congenital malformations (cardiac and diaphragmatic defects, celosomy - gastroschisis and umbilical hernia) was reported for non-selective inhibitors, in particular high doses of acetylsalicylic acid (aspirin).

Effect of mitochondrial aldehyde dehydrogenase-2 genotype on cardioprotection in patients with congenital heart disease

AIMS

About 40% of East Asians carry an aldehyde dehydrogenase-2*2 (ALDH2*2) allele, and the influence of the ALDH2*2 allele on human cardioprotection has not been studied. This study was designed to evaluate the effect of ALDH2*2 allele on cardioprotection of patients with congenital heart diseases after open-heart surgery.

METHODS AND RESULTS

The right atrial appendage was harvested before performing cardiopulmonary bypass in cyanotic and acyanotic congenital heart disease groups (n = 20 per group). Tissues were assayed to determine the impact of cyanosis on metabolic remodelling. A prospective cohort of Tetralogy of Fallot (TOF) patients (n = 118) was recruited to investigate the influence of the ALDH2*2 allele on cardioprotection after surgical repair. Myocardium samples were dissected after cardioplegia. ALDH2 activity, oxidative stress and glutathione (GSH) levels, and activating transcription factor-4 (ATF4) were analysed. After genotyping and grouping, all of the experimental and clinical results were compared between ALDH2*2 carriers and non-carriers. Cyanosis inhibited ALDH2 activity and led to aldehyde accumulation in ALDH2*2 carriers. This accumulation in turn increased expression of ATF4 and resulted in larger myocardium GSH pools. The differences in ALDH2 activity and GSH level between carriers and non-carriers disappeared during cardioplegic arrest, and more aldehydes accumulated in the non-carriers. Consequently, ALDH2*2 carriers showed lower postoperative troponin I, inotrope score, and shorter postoperative length of ICU and hospital stay.

CONCLUSIONS

ALDH2*2 carriers with cyanotic congenital heart disease were associated with an induced metabolic remodelling phenotype and a compensatory myocardium GSH pool. When ALDH2 activity was impaired during open-heart surgery, this larger GSH pool could lead to unexpectedly better cardioprotection. This may aid in the prediction of cardioprotection outcomes and identification of individualized cardioprotective strategies.