Three consecutive cases of acute liver failure in young women due to acetaminophen overdose: insights into Japanese social issues and transplantation landscape.

Acetaminophen (APAP) is an over-the-counter (OTC) drug known worldwide for its safety and efficacy. However, in Japan, OTC drug overdose has become a prominent social problem in recent years due to stricter regulations for other drugs, especially among young people, and APAP is an increasing cause of acute liver injury due to overdose. This report describes three consecutive cases of acute liver failure in young women (22, 22 and 19 years old) due to APAP overdose in December 2023. Despite severe liver injury, indicated by high ALT levels and coagulopathy, these cases recovered without requiring liver transplantation. This report discusses three cases of acute liver failure in young Japanese women following APAP overdose, reflecting a national increase in such cases due to increased misuse of OTC drugs and societal factors. Key findings include the need for early treatment with N-acetylcysteine (NAC) and the importance of mental health assessment in the management of overdose patients. The cases underscore the need for prompt team-based care to prevent serious outcomes and highlight the complexity of liver transplantation decisions in Japan, highlighting the need for comprehensive strategies to address the escalating problem of APAP overdose.

Assessment of high-dose acetylcysteine in acute high-risk paracetamol (acetaminophen) ingestion.

BACKGROUND: Prompt acetylcysteine treatment with standard doses (300 mg/kg over 21 h in divided doses) is almost universally effective in preventing hepatotoxicity after paracetamol (acetaminophen) overdose. However, hepatotoxicity is reported despite early treatment when paracetamol concentrations exceed 300 mg/L (1,985 µmol/L) at 4 h. Prior studies evaluating high-dose acetylcysteine to treat high-risk ingestions have shown mixed results. We compared outcomes in patients with high-risk ingestions receiving standard or high-dose acetylcysteine. METHODS: Records from a single poison center were reviewed from 1 January 2017 to 31 December 2022. We included cases of acute paracetamol ingestion treated with intravenous acetylcysteine with an initial paracetamol concentration above the "300 mg/L" (1,985 µmol/L) line on the Rumack-Matthew nomogram. We compared standard and high-dose acetylcysteine groups by odds ratios and multivariable logistic regression. We defined hepatotoxicity as aminotransferase activity >1,000 U/L. RESULTS: We included 190 cases. Fifty-six percent received standard-dose acetylcysteine while 44% received high-dose acetylcysteine. Treatment within 8 h yielded no difference in hepatotoxicity between groups (odds ratio 1.67, 95% CI 0.067-42.3). Among patients treated after 8 h, hepatoxicity was more common in the high-dose group (odds ratio 3.39, 95% CI 1.25-9.2) though odds of liver failure were similar (odds ratio 2.78, 95% CI 0.89-8.69). Eighty-eight percent of patients with hepatotoxicity had elevated aminotransferase activity at presentation. No patient died or received a liver transplant. DISCUSSION: Rates of hepatotoxicity were low in patients treated within 8 h regardless of acetylcysteine dose. Unexpectedly, high-dose acetylcysteine treatment was associated with an increased odds of hepatoxicity in those treated after 8 h, but most had abnormal aminotransferase activities at presentation and there was no difference in rates of liver failure. Limitations include the use of retrospective, voluntarily reported poison center data. CONCLUSIONS: Prompt treatment with acetylcysteine, regardless of dose, prevented hepatotoxicity in high-risk paracetamol ingestion.

Should high-dose N-acetylcysteine be given in cases of massive paracetamol overdoses: A narrative review.

N-acetylcysteine (NAC) is regarded as an effective treatment of paracetamol overdoses. However, in cases of "massive" paracetamol overdoses, recent studies indicate that patients may not be sufficiently treated with the standard dose of NAC (300 mg/kg over 20-21 h). The subject is further complicated because "massive overdoses" and "high-risk" are defined differently; some studies use the ingested amount (e.g., >40 g), and some studies use blood concentrations of paracetamol and transaminases. This narrative review investigates whether high-dose NAC significantly decreases the risk of hepatotoxicity in patients with massive paracetamol overdoses. Three observational studies were analysed; one study with 373 patients found no significant difference (odds ratio [OR]: 1.27, 95% confidence interval [CI]: 0.49-3.29). One study with 79 patients found a significant difference (OR: 0.27, 95% CI: 0.08-0.94). The third study with 89 patients found a significant difference in hepatoxicity between the groups (p = 0.043). There are no solid evidence to support that treatment with high-dose NAC significantly reduces the rate of hepatotoxicity in patients presenting with massive paracetamol overdoses. Differences in inclusion criteria in the included studies make the studies incomparable. This paper shows that standardized inclusion is needed to determine whether a high-dose NAC regimen should be included in clinical practice.

[Liver transplantation as treatment for acetaminophen poisoning]. / Trasplante hepático como tratamiento de intoxicación por paracetamol.

Acetaminophen is a commonly used analgesic and antipyretic drug, which has experienced an increase in its consumption in recent years in our environment. There has also been an increase in the number of accidental and intentional overdoses that were treated by the health system. Its toxicity is dose-dependent and can cause fulminant liver failure, becoming one of the main reasons for liver transplantation in English-speaking countries. The case of a 28-year-old woman with a history of major depression and five previous suicide attempts, who deliberately ingested a significant amount of paracetamol tablets, is here presented. She developed fulminant liver failure and metabolic acidosis, for which she underwent an emergency liver transplant due to the severity of her condition, from which she evolved favorably. The decision to perform a liver transplant in serious cases like this and under a condition of severe psychiatric vulnerability is challenging and must be carefully considered. This particular case illustrates the importance of multidisciplinary care including psychiatric evaluation in patients with acetaminophen poisoning.

El paracetamol es una droga analgésica y antipirética comúnmente utilizada, que ha experimentado un aumento en su consumo en los últimos años en nuestro medio. También se ha observado un incremento en el número de sobredosis accidentales e intencionales que fueron atendidas por el sistema de salud. Su toxicidad es dosis dependiente y puede causar falla hepática fulminante, convirtiéndose en una de las principales razones de trasplante hepático en países angloparlantes. Se presenta el caso de una mujer de 28 años con antecedentes de depresión mayor y cinco intentos de suicidio previos, quien ingirió deliberadamente una cantidad significativa de comprimidos de paracetamol. Desarrolló una falla hepática fulminante y acidosis metabólica, por lo que fue sometida a un trasplante hepático de emergencia debido a la gravedad de su condición evolucionando favorablemente. La decisión de realizar un trasplante hepático en casos graves como este y bajo una condición de vulnerabilidad psiquiátrica grave, es un desafío y debe considerarse cuidadosamente. Este caso en particular ilustra la importancia de la atención multidisciplinaria incluyendo la evaluación psiquiátrica en pacientes con intoxicación por paracetamol.

CYP2D6 inhibition by diphenhydramine leading to fatal hydrocodone overdose.

OBJECTIVES: Fatal drug overdoses often involve multiple co-intoxicants, including opioids. Hydrocodone, the most prescribed opioid for pain management, is metabolized to the active metabolite hydromorphone by hepatic CYP2D6. Inhibition of CYP2D6 by other compounds can disrupt the analgesic properties of hydrocodone and extend its half-life. Diphenhydramine is an over-the-counter cold medication and is known to inhibit CYP2D6 activity. CASE PRESENTATION: A woman in her late 50s was prescribed hydrocodone/acetaminophen (Norco® 10/325). Days before her death, she began taking diphenhydramine for cold symptoms. A post-mortem toxicology report detected the following compounds by High Performance Liquid Chromatography/Time of Flight-Mass Spectrometry (LC/TOF-MS) analysis: acetaminophen (14 µg/mL), hydrocodone (410 ng/mL), dihydrocodeine (24 ng/mL), and diphenhydramine (150 ng/mL). Hydromorphone was not detected (<2 ng/mL). All compounds were detected in therapeutic concentrations, except for hydrocodone, which was present at lethal concentrations. CONCLUSIONS: This case highlights a fatal drug-drug interaction between hydrocodone and diphenhydramine. The estimated total body burden of hydrocodone was 6- to 12-fold higher than acetaminophen, which is unexpected, as these two drugs were administered as a single formulation and have similar half-lives. Furthermore, hydromorphone was undetectable. Taken together, these findings are highly suggestive of a fatal opioid overdose precipitated by diphenhydramine.

The Insidious Enemy of the Liver: The Situation in Childhood Acetaminophen Poisoning and Early N-AC Treatment.

METHODS: This study was designed as a cross-sectional, observational, retrospective study. The variables of the study were paracetamol overdose, demographic information, poisoning mechanisms, clinical, laboratory findings, and clinical progression of the cases. The cases compared in whom treatment was initiated within the first 8 hours after poisoning and those in whom it was not. χ 2 , t test, and logistic regression analyses were conducted at appropriate facilities. RESULTS: Three hundred forty-eight cases were included in the study. N-AC treatment was initiated within the first 8 hours after poisoning in 322 cases (92.5%), and 26 cases received N-AC treatment after 8 hours after poisoning. Liver toxicity developed in 6 cases (1.7%), and indications for liver transplantation were met in 36 cases (10.3%). Among the 26 cases for which treatment was not initiated within the first 8 hours, 18 cases (69.2%) had indications for liver transplantation ( P < 0.01). It was found that N-AC within the first 8 hours reduced the risk by 43 times ( P = 0.02) and being older than 6 years, being admitted to the intensive care unit, and having alanine aminotransferase values above 1000 U/L increased the risk significantly ( P = 0.009, P = 0.005, P < 0.001). When a receiver operating characteristic curve was plotted for the 4th-hour blood acetaminophen level to predict liver transplantation, a value of 684.5 µg/mL emerged with 89% sensitivity and 93% specificity (area under the curve, 0.951). CONCLUSIONS: As a result, this study demonstrates the protective effect of early-initiated N-AC therapy on liver toxicity in pediatric acetaminophen poisoning cases. It also highlights a significant impact of gastrointestinal decontamination methods.

Paracetamol overdose in Danish children and adolescents during the Covid-19 restrictions.

INTRODUCTION: To assess the effect of long-term isolation on the mental state of Danish youth. This study aimed to investigate trends in paracetamol overdoses among people under 18 years of age in Denmark during Covid-19 restrictions as an indicator of mental health. METHODS: All patients under the age of 18 years presenting with paracetamol overdose at one of the 18 paediatric departments in Denmark from 2016 to 2021 were included. They were identified in all Danish hospital databases using specific diagnostic codes. RESULTS: From 2016 to 2021, a total of 3,217 people under 18 years of age were admitted for paracetamol overdose. Among these, 86% (n = 2,755) were girls and 14% (n = 462) were boys. During 2020, a slight (7%) decrease in admissions was observed among both boys and girls compared with the preceding four-year mean value. In 2021, the number of overdoses among girls exceeded by 35% the former all-time high from 2016. Furthermore, the number of overdoses among girls exceeded the pre-four-year period mean value by 43%. Among boys, an 8% increase was seen from the highest ever previous value recorded in 2019 and a 23% increase compared with the previous four-year mean value. CONCLUSIONS: During the first year of restrictions, a slight decrease in paracetamol overdoses was observed, possibly associated with limited accessibility. The second year showed a considerable increase in paracetamol overdoses, which may imply an affected mental state among youth during the prolonged lockdown restrictions as seen in previous epidemics. Therefore, further studies are warranted to develop a pandemic preparedness plan to protect general mental health. FUNDING: None. TRIAL REGISTRATION: Not relevant.

Acetaminophen overdose: analysis of 2018 US nationwide emergency database.

INTRODUCTION: Recognized risk factors for acetaminophen overdose include alcohol, opioids, and mood disorders. The aim of this study is to assess additional risk factors for acetaminophen overdose evaluated in the emergency department (ED). METHODS: A retrospective study was performed using the 2018 US Nationwide Emergency Department Sample (NEDS). All adult ED visits for acetaminophen overdose were included in the study group and those without it were taken as control. STATA, 16.1 was used to perform multivariable logistic regression analysis and adjusted odds ratios (ORadj) were reported. RESULTS: We identified 27,792 ED visits for acetaminophen overdose. Relative to non-acetaminophen ED visits, this group was younger (median age 32 vs 47 years; p < 0.0001), more often female (66.1% vs 57.0%; p < 0.0001), had higher ED charges ($3,506 vs $2,714; p < 0.0001), higher proportion of alcohol-related disorders (15.8% vs 3.5%; p < 0.0001), anxiety disorders (30.2% vs 8.3%; p < 0.0001), cannabis use (8.7% vs 1.4%; p < 0.0001), hematology/oncology diagnoses (13.3% vs 10.9%; p < 0.0001), mood disorders (52.4% vs 7.9%; p < 0.0001), opioid-related disorders (4.1% vs 1.0%; p < 0.0001), and suicide attempt/ideation (12.2% vs 1.1%; p < 0.0001). Multivariable analysis showed alcohol-related disorders (ORadj 2.67), anxiety disorders (ORadj 1.24), cannabis (ORadj 1.63), females (ORadj 1.45), Income Q3 (ORadj 1.09), hematology/oncology diagnoses (ORadj 1.40), mood disorders (ORadj 10.07), opioid-related disorders (ORadj 1.20), and suicide attempt/ideation (ORadj 1.68) were associated with acetaminophen overdose. CONCLUSION: In addition to previously recognized risks, our study demonstrated that cannabis use and hematologic/oncologic comorbidities were more common among acetaminophen-overdose ED visits. These new findings are concerning because of rapid legalization of cannabis and the increasing incidence of cancer worldwide. Additional investigation into these risks should be a priority for clinicians, policymakers, and researchers.

Has the rescheduling of modified-release paracetamol in Australia affected the frequency of overdoses?

OBJECTIVES: In June 2020, modified-release paracetamol (paracetamol-MR) preparations were up-scheduled from schedule-2 (available in pharmacy) to schedule-3 (available by request to a pharmacist only). The present study aims to ascertain whether up-scheduling affected the frequency of paracetamol-MR overdoses. METHODS: This is a retrospective cohort study of two data sets from 1 June 2017 to 31 May 2022. Monash Health data were extracted using the diagnosis of paracetamol overdose coding and electronic medical records data. Calls regarding paracetamol-MR overdoses to Victorian Poisons Information Centre (VPIC) were extracted from the Poisons centre call database. We used a quasi-experimental research design with interrupted time series analysis to evaluate the immediate impact and change in trend of poisoning-related calls and ED presentations before and after June 2020. The change in proportion of paracetamol-MR cases in both databases was analysed using the Χ2 test. RESULTS: The proportion of paracetamol-MR cases in both data sets did not change. From Monash Health, there was no level change in monthly paracetamol-MR overdose-related presentations following re-scheduling (rate ratio [RR] = 1.08, 95% confidence interval [CI] = 0.57-2.01). There was no change in monthly paracetamol-MR overdose-related calls to VPIC following re-scheduling (RR = 1.05, 95% CI = 0.96-1.14). CONCLUSION: The proportion of paracetamol-MR overdoses did not decrease after the up-scheduling to S3. Similarly, the frequency of overdoses by month remained similar. Further limitations on access to paracetamol products may need to be considered.

Assessing the impact of a new medical toxicology service on the treatment of paracetamol overdose at a large tertiary care hospital.

BACKGROUND: Paracetamol overdose is the most common cause of acute liver failure in the United States. Administration of acetylcysteine is the standard of care for this intoxication. Laboratory values and clinical criteria are used to guide treatment duration, but decision-making is nuanced and often complex and difficult. The purpose of this study was to evaluate the effect of the introduction of a medical toxicology service on the rate of errors in the management of paracetamol overdose. METHODS: This was a single center, retrospective, cohort evaluation. Patients with suspected paracetamol overdose were divided into two groups: those attending in the 1 year period before and those in the 1 year after the introduction of the medical toxicology service. The primary outcome was the frequency of deviations from the established management of paracetamol intoxication, using international guidelines as a reference. RESULTS: Fifty-four patients were eligible for the study (20 pre-toxicology-service, 34 post-toxicology-service). The frequency of incorrect therapeutic decisions was significantly lower in the post-toxicology service implementation versus the pre-implementation group (P = 0.005). DISCUSSION: Our study suggests that a medical toxicology service reduces the incidence of management errors, including the number of missed acetylcysteine doses in patients with paracetamol overdose. The limitations include the retrospective study design and that the study was conducted at a single center, which may limit generalizability. CONCLUSIONS: The implementation of a medical toxicology service was associated with a decrease in the number of errors in the management of paracetamol overdose.

Medication errors involving intravenous paracetamol in children: experience from enquiries to the National Poisons Information Service.

INTRODUCTION: Children are at higher risk of medication errors due to the complexity of drug prescribing and administration in this patient group. Intravenous (IV) paracetamol overdose differs from overdose by ingestion as there is no enteral absorptive buffering. We provide the first national UK data focusing on paediatric IV paracetamol poisoning. METHODS: All telephone enquiries to the National Poisons Information Service between 2008 and 2021 regarding children less than 18 years old in the UK concerning IV paracetamol overdose were extracted from the UK Poisons Information Database (UKPID). Data were analysed using descriptive statistics. RESULTS: Enquiries were made concerning 266 children, mostly involving children under the age of 1 year (n=145; 54.5%). Acute and staggered overdoses were the most frequent types of exposure. Common error themes included 10-fold overdose in 45 cases (16.9%) and inadvertent concomitant oral and IV dosing in 64 cases (24.1%). A high proportion of cases were asymptomatic (87.1%), with many calls regarding overdoses below the treatable dose of 60 mg/kg (41.4%). Treatment with the antidote acetylcysteine was advised in 113 cases (42.5%). CONCLUSIONS: Inadvertent IV paracetamol overdose appears to occur more frequently in young children. A significant proportion were calculation errors which were often 10-fold errors. While these errors have the potential for causing serious harm, thankfully most cases were asymptomatic. Errors with IV paracetamol might be reduced by electronic prescribing support systems, better communication regarding administration and consideration of whether other routes are more appropriate.

Intestinal injury in paracetamol overdose (ATOM-8).

BACKGROUND AND AIM: Paracetamol, a widely used medication, is known for its delayed hepatotoxicity in cases of overdose. However, the potential for intestinal toxicity resulting from very high paracetamol concentrations during absorption is not well explored. This study aims to investigate the presence of intestinal toxicity and its correlation with observations in early and late paracetamol toxicity. METHODS: Serial samples of 30 patients with acute paracetamol overdose (> 10 g or 200 mg/kg) were prospectively tested. Markers of enterocyte damage, including plasma intestinal fatty acid binding protein (IFABP) and selected gut-related microRNAs (miR-21, miR-122, miR-194, and miR-215), were analyzed. Sub-analysis was performed on patients presenting with hyperlactatemia defined as a lactate greater than 2 mmol/L within 12 h post ingestion. RESULTS: In paracetamol overdose patients, median plasma IFABP was significantly elevated compared with healthy controls (720 µg/L [interquartile range, IQR, 533-1644] vs 270 µg/L [IQR 153-558], P < 0.001). Four patients had early hyperlactatemia and had significantly higher median plasma IFABP compared with those without early hyperlactatemia (3028 µg/L [IQR 1399-3556] vs 574 µg/L [IQR 526-943], P = 0.007). Furthermore, two microRNAs (miR-122 and miR-215) were downregulated in early hyperlactatemia (P = 0.019 and P = 0.006, respectively). Plasma IFABP concentrations correlated with paracetamol concentration (Spearman's r = 0.55) and lactate (r = 0.60). CONCLUSIONS: Paracetamol overdose causes concentration-related intestinal toxicity, and this is a possible explanation for the early hyperlactatemia syndrome. Intestinal toxicity has potential impacts on pharmacokinetics of other agents ingested and on the evolution of hepatotoxicity. Further studies are required to explore the mechanisms and prognostic implications of intestinal toxicity.

Is Two Better Than Three? A Systematic Review of Two-bag Intravenous N-acetylcysteine Regimens for Acetaminophen Poisoning.

Introduction: Acetaminophen poisoning is commonly treated by emergency physicians. First-line therapy is N-acetylcysteine (NAC), traditionally administered intravenously via a US Food and Drug Administration (FDA)-approved three-bag protocol in which each bag has a unique concentration and infusion duration. Recently, simplified, off-label two-bag NAC infusion protocols have become more common. The purpose of this review is to summarize the effectiveness and safety of two-bag NAC. Methods: We undertook a comprehensive search of PubMed, EMBASE, and MEDLINE from inception to December 13, 2022, for articles describing human acetaminophen poisonings treated with two-bag NAC, defined as any regimen involving two discrete infusions in two separate bags. Outcomes included effectiveness (measured by incidence of liver injury); incidence of non-allergic anaphylactoid reactions (NAAR); gastrointestinal, cutaneous, and systemic reactions; treatments for NAARs; incidence of NAC-related medication errors; and delays or interruptions in NAC administration. Results: Twelve articles met final inclusion, 10 of which compared two-bag NAC to the three-bag regimen. Nine articles evaluated the two-bag/20-hour regimen, a simplified version of the FDA-approved three-bag regimen in which the traditional first and second bags are combined into a single four-hour infusion. Nine articles assessed comparative effectiveness of two-bag NAC in terms of liver injury, most commonly assessed for by incidence of hepatotoxicity (aspartate aminotransferase or alanine aminotransferase >1,000 international units per liter). No difference in liver injury was observed between two-bag and three-bag regimens. Of nine articles comparing incidence of NAARs, eight demonstrated statistically fewer NAARs with two-bag regimens, and one showed no difference. In seven articles evaluating treatment for NAARs (antihistamines, corticosteroids, epinephrine), all showed that patients received fewer medications for NAARs with two-bag NAC. Three articles evaluated NAC-related medication errors; two demonstrated no difference, while one study evaluating only children showed fewer errors with two-bag NAC. Two studies evaluated delays and/or interruptions in NAC infusions; both favored two-bag NAC. Conclusion: For patients with acetaminophen poisoning, two-bag NAC regimens appear to have similar outcomes to the traditional three-bag regimen in terms of liver injury. Two-bag NAC regimens are associated with fewer adverse events and fewer treatments for those events than the three-bag regimen and fewer interruptions in antidotal therapy.

Intoxicación intencional por paracetamol en adolescentes: un problema de salud creciente: a propósito de un caso / Intentional paracetamol poisoning in adolescents: a growing health problem: clinical case study / Intoxicação intencional por paracetamol em adolescentes: um problema de saúde crescente: relato de caso

La intoxicación por paracetamol de causa no intencional en niños pequeños, e intencional en adolescentes es un motivo de consulta cada vez más frecuente en los servicios de urgencia. La gravedad y el pronóstico de esta intoxicación están dados por el riesgo de falla hepática. Ante la sospecha de ingesta de paracetamol, se debe conocer el tiempo transcurrido, la cantidad de ingesta del fármaco, estimar la toxicidad de la dosis ingerida para predecir hepatotoxicidad, determinar las medidas de contaminación necesarias, dosificar paracetamol en sangre y evaluar la necesidad de administración de antídoto. Se describe el caso de una adolescente que con intención suicida presentó una intoxicación aguda por paracetamol con riesgo de daño hepático requiriendo decontaminación digestiva, administración de antídoto y abordaje interdisciplinario de sus problemas psicoemocionales.

Paracetamol intoxication due to an unintentional cause in young children, and intentional in adolescents, is an increasingly frequent cause for consultation in emergency services. The severity and prognosis of this poisoning is due to the risk of liver failure. Given the suspicion of paracetamol ingestion, the time passed since the ingestion, the amount of paracetamol ingested, the estimate of the dose ingested to predict hepatotoxicity, we must determine the necessary decontamination measures and the paracetamol dose in blood and evaluate the need to administer a paracetamol antidote. We describe the case of an adolescent who presented acute paracetamol poisoning with risk of liver damage resulting from a suicide attempt and who required digestive decontamination, antidote administration and an interdisciplinary approach to her psychological and emotional problems.

A intoxicação não intencional por paracetamol em crianças pequenas e a intoxicação intencional em adolescentes é um motivo cada vez mais comum de consulta em serviços de emergência. A gravidade e o prognóstico desse envenenamento são dados pelo risco de insuficiência hepática. Quando há suspeita de ingestão de paracetamol, o tempo decorrido desde que é ingerido, a quantidade de paracetamol ingerida, a estimação da dose ingerida para predizer hepatotoxicidade, utilizamse para determinar as medidas de contaminação necessárias, dosar paracetamol no sangue e avaliar a ne- cessidade de administração de antídoto. Descrevemos o caso de uma adolescente com intenção suicida que apresentou intoxicação aguda por paracetamol com risco de lesão hepática com necessidade de descontaminação digestiva, administração de antídoto e abordagem interdisciplinar de seus problemas psicoemocionais.

Metabolic Competency of Larval Zebrafish in Drug-Induced Liver Injury: A Case Study of Acetaminophen Poisoning.

Larval zebrafish is emerging as a new model organism for studying drug-induced liver injury (DILI) with superiorities in visual assessment, genetic engineering as well as high throughput. Metabolic bioactivation to form reactive intermediates is a common event that triggers DILI. This study first addressed the correlation between acetaminophen metabolism and hepatotoxicity in zebrafish larvae (3-day postfertilization) and demonstrated the occurrence of cytochrome P450 enzymes-mediated acetaminophen (APAP) bioactivation at early developmental stage through characterizing the dose-effect (0-1.6 mg/ml) and the time course (0-72 h) of liver injury and metabolism in the AB strain and LiPan transgenic line Tg(lfabp10a: DsRed; elaA:egfp) expressing the liver-specific fluorescent protein. APAP caused multiorgan developmental retardation and elicited dose- and time-dependent hepatotoxicity. Liver imaging revealed significant changes earlier than histological and biochemical measurements. APAP bioactivation in larval zebrafish was first confirmed by the detection of the glutathione conjugate of the reactive intermediate NAPQI (NAPQI-GSH) and subsequent mercapturate derivatives NAPQI-cysteine and NAPQI-N-acetylcysteine after even short (0.5-h postexposure) or low (0.2 mg/ml) APAP exposure. APAP overdose impaired metabolic function, in particular sulfation, whereas facilitated GSH depletion and APAP sulfate excretion. Meanwhile, APAP displayed triphasic accumulation in the larvae, agreeing with fluctuating metabolic capabilities with sulfation dominating the early larval developmental stage. Most importantly, the dose-response effects and time course of APAP accumulation and metabolism agree well with those of the liver injury development. Overall, larval zebrafish has developed mammalian-like metabolic function, enabling it an ideal model organism for high-throughput screening hepatotoxicity and mechanistic study of bioactivation-based DILI.

Coordinated activation of TGF-ß and BMP pathways promotes autophagy and limits liver injury after acetaminophen intoxication.

Ligands of the transforming growth factor-ß (TGF-ß) superfamily, including TGF-ßs, activins, and bone morphogenetic proteins (BMPs), have been implicated in hepatic development, homeostasis, and pathophysiology. We explored the mechanisms by which hepatocytes decode and integrate injury-induced signaling from TGF-ßs and activins (TGF-ß/Activin) and BMPs. We mapped the spatiotemporal patterns of pathway activation during liver injury induced by acetaminophen (APAP) in dual reporter mice carrying a fluorescent reporter of TGF-ß/Activin signaling and a fluorescent reporter of BMP signaling. APAP intoxication induced the expression of both reporters in a zone of cells near areas of tissue damage, which showed an increase in autophagy and demarcated the borders between healthy and injured tissues. Inhibition of TGF-ß superfamily signaling by overexpressing the inhibitor Smad7 exacerbated acute liver histopathology but eventually accelerated tissue recovery. Transcriptomic analysis identified autophagy as a process stimulated by TGF-ß1 and BMP4 in hepatocytes, with Trp53inp2, which encodes a rate-limiting factor for autophagy initiation, as the most highly induced autophagy-related gene. Collectively, these findings illustrate the functional interconnectivity of the TGF-ß superfamily signaling system, implicate the coordinated activation of TGF-ß/Activin and BMP pathways in balancing tissue reparatory and regenerative processes upon APAP-induced hepatotoxicity, and highlight opportunities and potential risks associated with targeting this signaling system for treating hepatic diseases.

Sensitivity of dose-estimations for acute acetaminophen overdose in predicting hepatotoxicity risk using the Rumack-Matthew Nomogram.

Timely assessment of acetaminophen concentration in overdose situations is not always available in resource-poor settings. The 150 mg/kg dose-estimate for acetaminophen is widely considered as criterion for acetaminophen overdose. Its sensitivity and specificity when compared to the 150 mg/L treatment line on the Rumack-Matthew Nomogram (150-treatment line) has rarely been evaluated. This is a retrospective chart review of acute acetaminophen overdose patients. We evaluated the sensitivity and specificity of the 150, 200 mg/kg and 8- and 10-g dose-estimates by plotting the serum acetaminophen levels and using 150-treatment line on the Nomogram as the treatment cut-off. A comparison of medical care costs was performed. We enrolled 784 cases for analysis. Median (IQR) age was 23 (20-28) years (81.9% female). There were 545 cases (69.5%) where the estimated ingested acetaminophen dose were ≥150 mg/kg and 406 cases (51.8%) with concentrations ≥150-treatment line. Hepatotoxicity and acute liver injury (ALI) occurred in 7.3% and 23.9%, respectively. The sensitivity and specificity of 150 mg/kg dose-estimate for the 150-treatment line were 92.6% (95% CI 89.6, 94.8) and 55.3% (95% CI 50.3, 60.2). Among patients with dose-estimate below150 mg/kg, none developed hepatotoxicity and 17 (7.1%) develop ALI. The administration of activated charcoal significantly decreased the risk of being above the 150-treatment line by half. In resource-poor setings, the use of 150 mg/kg dose-estimate as a stand-alone criteria for initiation of N-acetylcysteine therapy is satisfactory, especially when combined with decontamination with activated charcoal and follow up of aminotransferase at 24 h.