Alcohol exposure and paracetamol-induced hepatotoxicity

Potential deleterious effects of paracetamol dose regime used in Nigeria versus that of the United States of America

Paracetamol, also known as acetaminophen (N-acetyl-para-aminophenol, APAP) is the world's most used over-the-counter analgesic-antipyretic drug. Despite its good safety profile, acetaminophen can cause severe hepatotoxicity in overdose, and poisoning from paracetamol has become a major public health concern. Paracetamol is now the major cause of acute liver failure in the United States and Europe. This systematic review aims at examining the likelihood of paracetamol use in Nigeria causing more liver toxicity vis-à-vis the reduced maximum recommended daily adult dose of 3 g for the 500 mg tablet. Online searches were conducted in the databases of PubMed, Google Scholar and MEDLINE for publications using terms like "paracetamol toxicity," "acetaminophen and liver toxicity," "paracetamol and liver diseases in Nigeria," and other variants. Further search of related references in PubMed was carried out, and synthesis of all studies included in this review finalized. There were 94 studies that met the inclusion criteria. Evaluation of hepatic disorder was predicated mostly on a constellation of clinical features and limited clinical laboratory investigations. Determination of blood paracetamol concentration was rarely reported, thus excluding paracetamol poisoning as one of the likely causes of liver disorders in Nigeria. In Nigeria and elsewhere, several factors are known to increase paracetamol's predisposition to liver injury. They include: the over-the-counter status of paracetamol, use of fixed-dose combinations of paracetamol with other drugs, malnutrition, dose miscalculations, and chronic alcohol consumption. The tendency to exceed the new paracetamol maximum daily dose of 3 g in Nigeria may increase its risk for hepatotoxicity than observed in the United States of America known for emphasizing lower dose of the drug. In addition to recommending the new maximal daily paracetamol dose allowance, the historical maximum daily adult dose of 4 g should be de-emphasized in Nigeria.

In-vitro analysis on the potential use of dental pulp mesenchymal stem cells on arecoline-induced oral epithelial cells

To assess the protective role of the secretome of dental pulp mesenchymal stem cells on arecoline-induced epithelial-mesenchymal transition and senescence on epithelial cells of the oral mucosa. Effect of varying concentrations of arecoline extract and dental pulp mesenchymal stem cell condition media (DPSC-CM) were noted on oral mucosal epithelial cells. MTT assay, Annexin V-FITC/PI assay, and the quantitative gene expressions of BCL2, PUMA, BAD, BAX, CASP3, CASP9, CASP12, TGFB1, CST3, COL1A2, COL3A1, TIMP1, TIMP2, CDH1, and CDH2 were assessed. Oral mucosal epithelial cells exposed only to the arecoline were the control. 50% and 100% DPSC-CM decreased apoptosis-related gene expression in the cells exposed with 25 μM arecoline compared to the control. 50% DPSC-CM attenuated the expression of all fibrotic genes and EMT-related genes. 20% and 100% DPSC-CM showed differential effects on fibrotic and EMT-related genes. DPSC-CM inhibited apoptosis, and attenuated expression of fibrotic and EMT-related genes on arecoline treated human oral epithelial cells.

Selenium Status in Diet Affects Acetaminophen-Induced Hepatotoxicity via Interruption of Redox Environment

Aims: Drug-induced liver injury, especially acetaminophen (APAP)-induced liver injury, is a leading cause of liver failure worldwide. Mouse models were used to evaluate the effect of microelement selenium levels on the cellular redox environment and consequent hepatotoxicity of APAP. Results: APAP treatment affected mouse liver selenoprotein thioredoxin reductase (TrxR) activity and glutathione (GSH) level in a dose- and time-dependent manner. Decrease of mouse liver TrxR activity and glutathione level was an early event, and occurred concurrently with liver damage. The decreases in the GSH/glutathione disulfide form (GSSG) ratio and TrxR activity, and the increase of protein S-glutathionylation were correlated with the APAP-induced hepatotoxicity. Moreover, in APAP-treated mice both mild deprivation and excess supplementation with selenium increased the severity of liver injury compared with those observed in mice with normal dietary selenium levels. An increase in the oxidation state of the TrxR-mediated system, including cytosolic thioredoxin1 (Trx1) and peroxiredoxin1/2 (Prx1/2), and mitochondrial Trx2 and Prx3, was found in the livers from mice reared on selenium-deficient and excess selenium-supplemented diets upon APAP treatment. Innovation: This work demonstrates that both Trx and GSH systems are susceptible to APAP toxicity in vivo, and that the thiol-dependent redox environment is a key factor in determining the extent of APAP-induced hepatotoxicity. Dietary selenium and selenoproteins play critical roles in protecting mice against APAP overdose. Conclusion: APAP treatment in mice interrupts the function of the Trx and GSH systems, which are the main enzymatic antioxidant systems, in both the cytosol and mitochondria. Dietary selenium deficiency and excess supplementation both increase the risk of APAP-induced hepatotoxicity.

Ibuprofen Increases the Hepatotoxicity of Ethanol through Potentiating Oxidative Stress

Over 30 million prescriptions of NSAIDs (non-steroidal anti-inflammatory drugs) are issued every year. Considering that these drugs are available without a prescription as over the counter (OTC) drugs, their use will be astronomical. With the increasing use of NSAIDs, their adverse effects are drawing attention. Especially, stomach bleeding, kidney toxicity, liver toxicity, and neurological toxicity are reported as common. Ibuprofen, one of the extensively used NSAIDs along with aspirin, can also induce liver toxicity, but few studies are addressing this point. Here we examined the liver toxicity of ibuprofen and investigated whether co-exposure to ethanol can manifest synergistic effects. We employed 2D and 3D cultured human hepatoma cells, HepG2 to examine the synergistic hepatotoxicity of ibuprofen and alcohol concerning cell viability, morphology, and histology of 3D spheroids. As a result, ibuprofen and alcohol provoked synergistic hepatotoxicity against hepatocytes, and their toxicity increased prominently in 3D culture upon extended exposure. Oxidative stress appeared to be the mechanisms underlying the synergistic toxicity of ibuprofen and alcohol as evidenced by increased production of ROS and expression of the endogenous antioxidant system. Collectively, this study has demonstrated that ibuprofen and EtOH can induce synergistic hepatotoxicity, providing a line of evidence for caution against the use of ibuprofen in combination with alcohol.

Therapeutic Potential of Umbilical Cord Stem Cells for Liver Regeneration

The liver is a vital organ for life and the only internal organ that is capable of natural regeneration. Although the liver has high regeneration capacity, excessive hepatocyte death can lead to liver failure. Various factors can lead to liver damage including drug abuse, some natural products, alcohol, hepatitis, and autoimmunity. Some models for studying liver injury are APAP-based model, Fas ligand (FasL), D-galactosamine/endotoxin (Gal/ET), Concanavalin A, and carbon tetrachloride-based models. The regeneration of the liver can be carried out using umbilical cord blood stem cells which have various advantages over other stem cell types used in liver transplantation. UCB-derived stem cells lack tumorigenicity, have karyotype stability and high immunomodulatory, low risk of graft versus host disease (GVHD), low risk of transmitting somatic mutations or viral infections, and low immunogenicity. They are readily available and their collection is safe and painless. This review focuses on recent development and modern trends in the use of umbilical cord stem cells for the regeneration of liver fibrosis.

Are some people at increased risk of paracetamol-induced liver injury? A critical review of the literature

Purpose

Paracetamol is one of the world’s most commonly used drugs. In overdose, it is well established to be hepatotoxic. The aim of this review was to identify factors that have been, or actually are, associated with the development of liver injury after paracetamol exposure in humans.

Method

Google Scholar and PubMed were searched on various dates between December 2016 and March 2017. Papers identified had their references analysed for further studies that might be relevant.

Results

At the time of writing, there was little good quality clinical evidence—from studies of paracetamol overdose or therapeutic use—to suggest that any groups of people are relatively protected from, or are at greater risk of, liver injury. The factors that were historically used to indicate higher risk in the UK have no good quality clinical evidence to support their re-introduction into clinical practice. The safe (and still effective) oral dose of paracetamol in patients weighing less than 50 kg has not been established.

Conclusion

There is no patient group that is unequivocally at elevated risk of paracetamol-induced liver toxicity. We propose two clinical scenarios that warrant further research. Firstly, there is a need to establish whether the dose of paracetamol should be reduced in patients with low body weight. Secondly, if or when genomic information regarding individual patients becomes readily available to inform prescribing, we propose the contribution of the genome to paracetamol toxicity should be re-investigated with robustly designed studies. Such studies could enhance the safe use of one of the most frequently taken drugs.

Electronic supplementary material

The online version of this article (10.1007/s00228-017-2356-6) contains supplementary material, which is available to authorized users.

Clinical update on benefit versus risks of oral paracetamol alone or with codeine: still a good option?

BACKGROUND

After decades of worldwide use of paracetamol/acetaminophen as a popular and apparently safe prescription and over-the-counter medicine, the future role of this poorly understood analgesic has been seriously questioned by recent concerns about prenatal, cardiovascular (CV) and hepatic safety, and also about its analgesic efficacy. At the same time the usefulness of codeine in combination products has come under debate.

METHODS

Based on a PubMed database literature search on the terms efficacy, safety, paracetamol, acetaminophen, codeine and their combinations up to and including June 2016, this clinical update reviews the current evidence of the benefit and risks of oral paracetamol alone and with codeine for mild-to-moderate pain in adults, and compares the respective efficacy and safety profiles with those of nonsteroidal anti-inflammatory drugs (NSAIDs).

RESULTS

Whereas there is a clear strong association of NSAID use and gastrointestinal (GI) and CV morbidity and mortality, evidence for paracetamol with and without codeine supports the recommended use even in most vulnerable individuals, such as the elderly, pregnant women, alcoholics, and compromised GI and CV patients. The controversies and widespread misconceptions about the complex hepatic metabolism and potential hepatotoxicity have been corrected by recent reviews, and paracetamol remains the first-line nonopioid analgesic in patients with liver diseases if notes of caution are applied.

CONCLUSION

Due to its safety and tolerability profile paracetamol remained a first-line treatment in many international guidelines. Alone and with codeine it is a safe and effective option in adults, whilst NSAIDs are obviously less safe as alternatives, given the risk of potentially fatal GI and CV adverse effects.

Dihydroartemisinin alleviates bile duct ligation-induced liver fibrosis and hepatic stellate cell activation by interfering with the PDGF-βR/ERK signaling pathway

Liver fibrosis represents a frequent event following chronic insult to trigger wound healing responses in the liver. Activation of hepatic stellate cells (HSCs), which is a pivotal event during liver fibrogenesis, is accompanied by enhanced expressions of a series of marker proteins and pro-fibrogenic signaling molecules. Artemisinin, a powerful antimalarial medicine, is extracted from the Chinese herb Artemisia annua L., and can inhibit the proliferation of cancer cells. Dihydroartemisinin (DHA), the major active metabolite of artemisinin, is able to attenuate lung injury and fibrosis. However, the effect of DHA on liver fibrosis remains unclear. The aim of this study was to investigate the effect of DHA on bile duct ligation-induced injury and fibrosis in rats. DHA improved the liver histological architecture and attenuated collagen deposition in the fibrotic rat liver. Experiments in vitro showed that DHA inhibited the proliferation of HSCs and arrested the cell cycle at the S checkpoint by altering several cell-cycle regulatory proteins. Moreover, DHA reduced the protein expressions of a-SMA, α1 (I) collagen and fibronectin, being associated with interference of the platelet-derived growth factor β receptor (PDGF-βR)-mediated ERK pathway. These data collectively revealed that DHA relieved liver fibrosis possibly by targeting HSCs via the PDGF-βR/ERK pathway. DHA may be a therapeutic antifibrotic agent for the treatment of hepatic fibrosis.

Low Dose Acetaminophen Induces Reversible Mitochondrial Dysfunction Associated with Transient c-Jun N-Terminal Kinase Activation in Mouse Liver

Acetaminophen (APAP) overdose causes hepatotoxicity involving mitochondrial dysfunction and c-jun N-terminal kinase (JNK) activation. Because the safe limit of APAP dosing is controversial, our aim was to evaluate the role of the mitochondrial permeability transition (MPT) and JNK in mitochondrial dysfunction after APAP dosing considered nontoxic by criteria of serum alanine aminotransferase (ALT) release and histological necrosis in vivo. C57BL/6 mice were given APAP with and without the MPT inhibitor, N-methyl-4-isoleucine cyclosporin (NIM811), or the JNK inhibitor, SP600125. Fat droplet formation, cell viability, and mitochondrial function in vivo were monitored by intravital multiphoton microscopy. Serum ALT, liver histology, total JNK, and activated phospho(p)JNK were also assessed. High APAP (300 mg/kg) caused ALT release, necrosis, irreversible mitochondrial dysfunction, and hepatocellular death. By contrast, lower APAP (150 mg/kg) caused reversible mitochondrial dysfunction and fat droplet formation in hepatocytes without ALT release or necrosis. Mitochondrial protein N-acetyl-p-benzoquinone imine adducts correlated with early JNK activation, but irreversible mitochondrial depolarization and necrosis at high dose were associated with sustained JNK activation and translocation to mitochondria. NIM811 prevented cell death and/or mitochondrial depolarization after both high and low dose APAP. After low dose, SP600125 decreased mitochondrial depolarization. In conclusion, low dose APAP produces reversible MPT-dependent mitochondrial dysfunction and steatosis in hepatocytes without causing ALT release or necrosis, whereas high dose leads to irreversible mitochondrial dysfunction and cell death associated with sustained JNK activation. Thus, nontoxic APAP has the potential to cause transient mitochondrial dysfunction that may synergize with other stresses to promote liver damage and steatosis.

Inhibition of human alcohol and aldehyde dehydrogenases by acetaminophen: Assessment of the effects on first-pass metabolism of ethanol

Acetaminophen is one of the most widely used over-the-counter analgesic, antipyretic medications. Use of acetaminophen and alcohol are commonly associated. Previous studies showed that acetaminophen might affect bioavailability of ethanol by inhibiting gastric alcohol dehydrogenase (ADH). However, potential inhibitions by acetaminophen of first-pass metabolism (FPM) of ethanol, catalyzed by the human ADH family and by relevant aldehyde dehydrogenase (ALDH) isozymes, remain undefined. ADH and ALDH both exhibit racially distinct allozymes and tissue-specific distribution of isozymes, and are principal enzymes responsible for ethanol metabolism in humans. In this study, we investigated acetaminophen inhibition of ethanol oxidation with recombinant human ADH1A, ADH1B1, ADH1B2, ADH1B3, ADH1C1, ADH1C2, ADH2, and ADH4, and inhibition of acetaldehyde oxidation with recombinant human ALDH1A1 and ALDH2. The investigations were done at near physiological pH 7.5 and with a cytoplasmic coenzyme concentration of 0.5 mM NAD(+). Acetaminophen acted as a noncompetitive inhibitor for ADH enzymes, with the slope inhibition constants (Kis) ranging from 0.90 mM (ADH2) to 20 mM (ADH1A), and the intercept inhibition constants (Kii) ranging from 1.4 mM (ADH1C allozymes) to 19 mM (ADH1A). Acetaminophen exhibited noncompetitive inhibition for ALDH2 (Kis = 3.0 mM and Kii = 2.2 mM), but competitive inhibition for ALDH1A1 (Kis = 0.96 mM). The metabolic interactions between acetaminophen and ethanol/acetaldehyde were assessed by computer simulation using inhibition equations and the determined kinetic constants. At therapeutic to subtoxic plasma levels of acetaminophen (i.e., 0.2-0.5 mM) and physiologically relevant concentrations of ethanol (10 mM) and acetaldehyde (10 μm) in target tissues, acetaminophen could inhibit ADH1C allozymes (12-26%) and ADH2 (14-28%) in the liver and small intestine, ADH4 (15-31%) in the stomach, and ALDH1A1 (16-33%) and ALDH2 (8.3-19%) in all 3 tissues. The results suggest that inhibition by acetaminophen of hepatic and gastrointestinal FPM of ethanol through ADH and ALDH pathways might become significant at higher, subtoxic levels of acetaminophen.

Acetaminophen (paracetamol)

Therapeutic Reviews aim to provide essential independent information for health professionals about drugs used in palliative and hospice care. Additional content is available on www.palliativedrugs.com. Country-specific books (Hospice and Palliative Care Formulary USA, and Palliative Care Formulary, British and Canadian editions) are also available and can be ordered from www.palliativedrugs.com. The series editors welcome feedback on the articles (hq@palliativedrugs.com).

Hospitalizations for suicide-related drug poisonings and co-occurring alcohol overdoses in adolescents (ages 12-17) and young adults (ages 18-24) in the United States, 1999-2008: results from the Nationwide Inpatient Sample

Drug poisoning is the leading method of suicide-related deaths among females and third among males in the United States. Alcohol can increase the severity of drug poisonings, yet the prevalence of alcohol overdoses in suicide-related drug poisonings (SRDP) remains unclear. Data from the Nationwide Inpatient Sample was examined to determine rates of inpatient hospital stays for SRDP and co-occurring alcohol overdoses in adolescents (ages 12-17) and young adults (ages 18-24) between 1999 and 2008. Among adolescents, there were 14,615 hospitalizations for drug poisonings in 2008, of which 72% (10,462) were suicide-related at a cost of $43 million. Rates of SRDP in this age group decreased between 1999 and 2008. The prevalence of co-occurring alcohol overdoses increased from 5% in 1999 to 7% in 2008. Among young adults, there were 32,471 hospitalizations for drug poisonings in 2008, of which 64% (20,746) were suicide-related at a cost of $110 million. Rates of SRDP did not change significantly between 1999 and 2008. The prevalence of co-occurring alcohol overdoses increased from 14% in 1999 to 20% in 2008. Thus, while rates of SRDP decreased for adolescents and remained unchanged for young adults, the prevalence of co-occurring alcohol overdoses increased for both age groups. Such hospitalizations provide important opportunities to employ intervention techniques to prevent further suicide attempts.

Acetaminophen usage patterns and concentrations of glutathione and gamma-glutamyl transferase in alcoholic subjects

STUDY OBJECTIVES

To determine if subjects with chronic alcoholism are predisposed to acetaminophen-induced hepatotoxicity, and to determine the contributing factors.

DESIGN

Prospective cohort study.

SETTING

Community-based crisis intervention center.

SUBJECTS

One hundred eighty-eight subjects who answered "yes" to at least one of the four questions on the CAGE (Cut down-Annoyed-Guilty-Eye-opener) questionnaire for identifying alcoholism, and 10 healthy volunteers (controls).

INTERVENTION

A history, physical examination, urine toxicologic analysis, ethanol and drug therapy history, and venous blood samples were collected on all subjects.

MEASUREMENTS AND MAIN RESULTS

Venous blood was analyzed for a liver profile, prothrombin time, and total and oxidized glutathione concentrations. A significantly higher proportion of daily drinkers were regular daily users (29.2% [45/154] vs 11.8% [4/34], p=0.0497) as well as abusers (35.7% [55/154] vs 14.7% [5/34], p=0.0237) of acetaminophen compared with non daily drinkers. Alcoholic subjects with elevated gamma-glutamyl transferase (GGT >or= 51 U/L) levels had significantly lower median plasma glutathione concentrations (2.33 micromol/L, 95% confidence interval [CI] 1.74-2.69 micromol/L) compared with those of alcoholic subjects with normal GGT concentrations (5.97 micromol/L, 95% CI 4.39-7.03 micromol/L, p<0.0001) and healthy volunteers (6.59 micromol/L, 95% CI 4.79-9.65 micromol/L, p=0.0002). A significant inverse correlation was also noted between the GGT concentration and the plasma total glutathione concentration (r = -0.62, p<0.0001). None of the 188 subjects met all preset criteria for hepatotoxicity.

CONCLUSIONS

Daily drinkers were more than twice as likely as non daily drinkers to be regular daily acetaminophen users and abusers. Alcoholic subjects with elevated GGT concentrations had significantly lower plasma total glutathione concentrations, and plasma total glutathione concentrations inversely correlated with GGT concentrations. Elevated GGT concentrations may be a clinical marker of depleted glutathione in alcoholic subjects. Acetaminophen-induced hepatotoxicity appears to be uncommon in alcoholic subjects, despite the 31.9% (60/188 patients) who took doses that are potentially hepatotoxic.

Hepatoprotective and Antioxidant Activities ofVernonia amygdalinaon Acetaminophen-Induced Hepatic Damage in Mice

Vernonia amygdalina Del. (Family Compositae) is used in Nigerian folk medicine as a tonic and remedy against constipation, fever, high blood pressure, and many infectious diseases. We have evaluated the hepatoprotective and antioxidant effects of an aqueous extract of V. amygdalina leaves against acetaminophen-induced hepatotoxicity and oxidative stress in mice in vivo. Activities of liver marker enzymes in serum (glutamate-oxaloacetate transaminase, glutamate-pyruvate transaminase, lactate dehydrogenase, and alkaline phosphatase) and bilirubin levels were determined colorimetrically, while catalase activity, lipid peroxidation products, thiobarbituric acid-reactive substances (TBARS), iron, and total protein concentrations were measured in liver homogenate. Acetaminophen challenge (300 mg/kg, i.p) for 7 days caused significant (P < .01) increases in the levels of bilirubin, liver enzymes, TBARS, and iron, while catalase activity and total protein level were reduced significantly (P < .01). Preadministration of V. amygdalina resulted in a dose-dependent (50-100 mg/kg) reversal of acetaminophen-induced alterations of all the liver function parameters by 51.9-84.9%. Suppression of acetaminophen-induced lipid peroxidation and oxidative stress by the extract was also dose-dependent (50-100 mg/kg). The results of this study suggest that V. amygdalina elicits hepatoprotectivity through antioxidant activity on acetaminophen-induced hepatic damage in mice.

Ethanol binging exacerbates sinusoidal endothelial and parenchymal injury elicited by acetaminophen

BACKGROUND/AIMS

The pathophysiology of binge drinking of ethanol and its potentiation of acetaminophen (APAP) toxicity has received very little attention. To evaluate if ethanol binging sensitizes hepatic sinusoidal endothelial cells (SEC) and liver to APAP toxicity.

METHODS

The histopathological responses to APAP were evaluated in the livers of mice gavaged with APAP alone, following a single, week-end type ethanol binge (4 g/kg every 12 h x 5 doses) or three weekly binges.

RESULTS

Six hours after APAP, 600 mg/kg elicited severe centrilobular necrosis together with hemorrhagic congestion and infiltration of erythrocytes into the Space of Disse through large gaps that had formed in SEC. There was no evidence of parenchymal injury at 2 h, but gaps already were formed through the cytoplasm of the SEC by coalescence of fenestrae. A single binge followed by 300 mg/kg APAP elicited SEC and parenchymal injury equivalent to 600 mg/kg APAP alone at 2 and 6 h. The responses were exacerbated following three binges. Lower glutathione levels in the liver were shown in ethanol-binged animals.

CONCLUSIONS

Ethanol binging increases APAP hepatotoxicity. SEC are an early target for APAP-induced injury and ethanol binging enhances the SEC injury prior to evidence of parenchymal cell injury.

Drug-induced liver disease

The year 2002 saw a warning from the US Food and Drug Administration not to use the diet agent, Lipokinetix, and brought to light a few new agents as potential hepatotoxins. Numerous other reports confirmed the hepatotoxicity of several previously described agents. Refinements in causality assessment remain an important aspect in defining drug-induced liver disease and proposed new upper limits of normal for alanine aminotransferase that are lower than most laboratories currently report may require rethinking our definition of "normal liver function tests." Chronic viral hepatitis B and C remain important risk factors for antiretroviral-induced liver injury in patients co-infected with the human immunodeficiency virus and in patients receiving antituberculosis therapy. Acetaminophen retains its status as the most common cause of acute drug-induced liver failure in the United States and in many other countries. Several papers addressed the issue of accidental versus intentional overdoses, the role of alcohol consumption as a risk factor, and newer aspects of treating and preventing acetaminophen injury to the liver. Finally, the use of potentially hepatotoxic medications in patients with underlying liver disease continues to be a controversial topic and a rational approach to the use of such drugs in this setting is provided.